11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * linux/fs/namei.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Copyright (C) 1991, 1992 Linus Torvalds 51da177e4SLinus Torvalds */ 61da177e4SLinus Torvalds 71da177e4SLinus Torvalds /* 81da177e4SLinus Torvalds * Some corrections by tytso. 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 111da177e4SLinus Torvalds /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname 121da177e4SLinus Torvalds * lookup logic. 131da177e4SLinus Torvalds */ 141da177e4SLinus Torvalds /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. 151da177e4SLinus Torvalds */ 161da177e4SLinus Torvalds 171da177e4SLinus Torvalds #include <linux/init.h> 181da177e4SLinus Torvalds #include <linux/module.h> 191da177e4SLinus Torvalds #include <linux/slab.h> 201da177e4SLinus Torvalds #include <linux/fs.h> 211da177e4SLinus Torvalds #include <linux/namei.h> 221da177e4SLinus Torvalds #include <linux/quotaops.h> 231da177e4SLinus Torvalds #include <linux/pagemap.h> 240eeca283SRobert Love #include <linux/fsnotify.h> 251da177e4SLinus Torvalds #include <linux/personality.h> 261da177e4SLinus Torvalds #include <linux/security.h> 276146f0d5SMimi Zohar #include <linux/ima.h> 281da177e4SLinus Torvalds #include <linux/syscalls.h> 291da177e4SLinus Torvalds #include <linux/mount.h> 301da177e4SLinus Torvalds #include <linux/audit.h> 3116f7e0feSRandy Dunlap #include <linux/capability.h> 32834f2a4aSTrond Myklebust #include <linux/file.h> 335590ff0dSUlrich Drepper #include <linux/fcntl.h> 3408ce5f16SSerge E. Hallyn #include <linux/device_cgroup.h> 355ad4e53bSAl Viro #include <linux/fs_struct.h> 361da177e4SLinus Torvalds #include <asm/uaccess.h> 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds /* [Feb-1997 T. Schoebel-Theuer] 411da177e4SLinus Torvalds * Fundamental changes in the pathname lookup mechanisms (namei) 421da177e4SLinus Torvalds * were necessary because of omirr. The reason is that omirr needs 431da177e4SLinus Torvalds * to know the _real_ pathname, not the user-supplied one, in case 441da177e4SLinus Torvalds * of symlinks (and also when transname replacements occur). 451da177e4SLinus Torvalds * 461da177e4SLinus Torvalds * The new code replaces the old recursive symlink resolution with 471da177e4SLinus Torvalds * an iterative one (in case of non-nested symlink chains). It does 481da177e4SLinus Torvalds * this with calls to <fs>_follow_link(). 491da177e4SLinus Torvalds * As a side effect, dir_namei(), _namei() and follow_link() are now 501da177e4SLinus Torvalds * replaced with a single function lookup_dentry() that can handle all 511da177e4SLinus Torvalds * the special cases of the former code. 521da177e4SLinus Torvalds * 531da177e4SLinus Torvalds * With the new dcache, the pathname is stored at each inode, at least as 541da177e4SLinus Torvalds * long as the refcount of the inode is positive. As a side effect, the 551da177e4SLinus Torvalds * size of the dcache depends on the inode cache and thus is dynamic. 561da177e4SLinus Torvalds * 571da177e4SLinus Torvalds * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink 581da177e4SLinus Torvalds * resolution to correspond with current state of the code. 591da177e4SLinus Torvalds * 601da177e4SLinus Torvalds * Note that the symlink resolution is not *completely* iterative. 611da177e4SLinus Torvalds * There is still a significant amount of tail- and mid- recursion in 621da177e4SLinus Torvalds * the algorithm. Also, note that <fs>_readlink() is not used in 631da177e4SLinus Torvalds * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() 641da177e4SLinus Torvalds * may return different results than <fs>_follow_link(). Many virtual 651da177e4SLinus Torvalds * filesystems (including /proc) exhibit this behavior. 661da177e4SLinus Torvalds */ 671da177e4SLinus Torvalds 681da177e4SLinus Torvalds /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: 691da177e4SLinus Torvalds * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL 701da177e4SLinus Torvalds * and the name already exists in form of a symlink, try to create the new 711da177e4SLinus Torvalds * name indicated by the symlink. The old code always complained that the 721da177e4SLinus Torvalds * name already exists, due to not following the symlink even if its target 731da177e4SLinus Torvalds * is nonexistent. The new semantics affects also mknod() and link() when 741da177e4SLinus Torvalds * the name is a symlink pointing to a non-existant name. 751da177e4SLinus Torvalds * 761da177e4SLinus Torvalds * I don't know which semantics is the right one, since I have no access 771da177e4SLinus Torvalds * to standards. But I found by trial that HP-UX 9.0 has the full "new" 781da177e4SLinus Torvalds * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the 791da177e4SLinus Torvalds * "old" one. Personally, I think the new semantics is much more logical. 801da177e4SLinus Torvalds * Note that "ln old new" where "new" is a symlink pointing to a non-existing 811da177e4SLinus Torvalds * file does succeed in both HP-UX and SunOs, but not in Solaris 821da177e4SLinus Torvalds * and in the old Linux semantics. 831da177e4SLinus Torvalds */ 841da177e4SLinus Torvalds 851da177e4SLinus Torvalds /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink 861da177e4SLinus Torvalds * semantics. See the comments in "open_namei" and "do_link" below. 871da177e4SLinus Torvalds * 881da177e4SLinus Torvalds * [10-Sep-98 Alan Modra] Another symlink change. 891da177e4SLinus Torvalds */ 901da177e4SLinus Torvalds 911da177e4SLinus Torvalds /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: 921da177e4SLinus Torvalds * inside the path - always follow. 931da177e4SLinus Torvalds * in the last component in creation/removal/renaming - never follow. 941da177e4SLinus Torvalds * if LOOKUP_FOLLOW passed - follow. 951da177e4SLinus Torvalds * if the pathname has trailing slashes - follow. 961da177e4SLinus Torvalds * otherwise - don't follow. 971da177e4SLinus Torvalds * (applied in that order). 981da177e4SLinus Torvalds * 991da177e4SLinus Torvalds * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT 1001da177e4SLinus Torvalds * restored for 2.4. This is the last surviving part of old 4.2BSD bug. 1011da177e4SLinus Torvalds * During the 2.4 we need to fix the userland stuff depending on it - 1021da177e4SLinus Torvalds * hopefully we will be able to get rid of that wart in 2.5. So far only 1031da177e4SLinus Torvalds * XEmacs seems to be relying on it... 1041da177e4SLinus Torvalds */ 1051da177e4SLinus Torvalds /* 1061da177e4SLinus Torvalds * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) 107a11f3a05SArjan van de Ven * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives 1081da177e4SLinus Torvalds * any extra contention... 1091da177e4SLinus Torvalds */ 1101da177e4SLinus Torvalds 1111da177e4SLinus Torvalds /* In order to reduce some races, while at the same time doing additional 1121da177e4SLinus Torvalds * checking and hopefully speeding things up, we copy filenames to the 1131da177e4SLinus Torvalds * kernel data space before using them.. 1141da177e4SLinus Torvalds * 1151da177e4SLinus Torvalds * POSIX.1 2.4: an empty pathname is invalid (ENOENT). 1161da177e4SLinus Torvalds * PATH_MAX includes the nul terminator --RR. 1171da177e4SLinus Torvalds */ 118858119e1SArjan van de Ven static int do_getname(const char __user *filename, char *page) 1191da177e4SLinus Torvalds { 1201da177e4SLinus Torvalds int retval; 1211da177e4SLinus Torvalds unsigned long len = PATH_MAX; 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds if (!segment_eq(get_fs(), KERNEL_DS)) { 1241da177e4SLinus Torvalds if ((unsigned long) filename >= TASK_SIZE) 1251da177e4SLinus Torvalds return -EFAULT; 1261da177e4SLinus Torvalds if (TASK_SIZE - (unsigned long) filename < PATH_MAX) 1271da177e4SLinus Torvalds len = TASK_SIZE - (unsigned long) filename; 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds 1301da177e4SLinus Torvalds retval = strncpy_from_user(page, filename, len); 1311da177e4SLinus Torvalds if (retval > 0) { 1321da177e4SLinus Torvalds if (retval < len) 1331da177e4SLinus Torvalds return 0; 1341da177e4SLinus Torvalds return -ENAMETOOLONG; 1351da177e4SLinus Torvalds } else if (!retval) 1361da177e4SLinus Torvalds retval = -ENOENT; 1371da177e4SLinus Torvalds return retval; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds char * getname(const char __user * filename) 1411da177e4SLinus Torvalds { 1421da177e4SLinus Torvalds char *tmp, *result; 1431da177e4SLinus Torvalds 1441da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 1451da177e4SLinus Torvalds tmp = __getname(); 1461da177e4SLinus Torvalds if (tmp) { 1471da177e4SLinus Torvalds int retval = do_getname(filename, tmp); 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds result = tmp; 1501da177e4SLinus Torvalds if (retval < 0) { 1511da177e4SLinus Torvalds __putname(tmp); 1521da177e4SLinus Torvalds result = ERR_PTR(retval); 1531da177e4SLinus Torvalds } 1541da177e4SLinus Torvalds } 1551da177e4SLinus Torvalds audit_getname(result); 1561da177e4SLinus Torvalds return result; 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds #ifdef CONFIG_AUDITSYSCALL 1601da177e4SLinus Torvalds void putname(const char *name) 1611da177e4SLinus Torvalds { 1625ac3a9c2SAl Viro if (unlikely(!audit_dummy_context())) 1631da177e4SLinus Torvalds audit_putname(name); 1641da177e4SLinus Torvalds else 1651da177e4SLinus Torvalds __putname(name); 1661da177e4SLinus Torvalds } 1671da177e4SLinus Torvalds EXPORT_SYMBOL(putname); 1681da177e4SLinus Torvalds #endif 1691da177e4SLinus Torvalds 1705909ccaaSLinus Torvalds /* 1715909ccaaSLinus Torvalds * This does basic POSIX ACL permission checking 1725909ccaaSLinus Torvalds */ 1735909ccaaSLinus Torvalds static int acl_permission_check(struct inode *inode, int mask, 1745909ccaaSLinus Torvalds int (*check_acl)(struct inode *inode, int mask)) 1755909ccaaSLinus Torvalds { 1765909ccaaSLinus Torvalds umode_t mode = inode->i_mode; 1775909ccaaSLinus Torvalds 1785909ccaaSLinus Torvalds mask &= MAY_READ | MAY_WRITE | MAY_EXEC; 1795909ccaaSLinus Torvalds 1805909ccaaSLinus Torvalds if (current_fsuid() == inode->i_uid) 1815909ccaaSLinus Torvalds mode >>= 6; 1825909ccaaSLinus Torvalds else { 1835909ccaaSLinus Torvalds if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { 1845909ccaaSLinus Torvalds int error = check_acl(inode, mask); 1855909ccaaSLinus Torvalds if (error != -EAGAIN) 1865909ccaaSLinus Torvalds return error; 1875909ccaaSLinus Torvalds } 1885909ccaaSLinus Torvalds 1895909ccaaSLinus Torvalds if (in_group_p(inode->i_gid)) 1905909ccaaSLinus Torvalds mode >>= 3; 1915909ccaaSLinus Torvalds } 1925909ccaaSLinus Torvalds 1935909ccaaSLinus Torvalds /* 1945909ccaaSLinus Torvalds * If the DACs are ok we don't need any capability check. 1955909ccaaSLinus Torvalds */ 1965909ccaaSLinus Torvalds if ((mask & ~mode) == 0) 1975909ccaaSLinus Torvalds return 0; 1985909ccaaSLinus Torvalds return -EACCES; 1995909ccaaSLinus Torvalds } 2001da177e4SLinus Torvalds 2011da177e4SLinus Torvalds /** 2021da177e4SLinus Torvalds * generic_permission - check for access rights on a Posix-like filesystem 2031da177e4SLinus Torvalds * @inode: inode to check access rights for 2041da177e4SLinus Torvalds * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 2051da177e4SLinus Torvalds * @check_acl: optional callback to check for Posix ACLs 2061da177e4SLinus Torvalds * 2071da177e4SLinus Torvalds * Used to check for read/write/execute permissions on a file. 2081da177e4SLinus Torvalds * We use "fsuid" for this, letting us set arbitrary permissions 2091da177e4SLinus Torvalds * for filesystem access without changing the "normal" uids which 2101da177e4SLinus Torvalds * are used for other things.. 2111da177e4SLinus Torvalds */ 2121da177e4SLinus Torvalds int generic_permission(struct inode *inode, int mask, 2131da177e4SLinus Torvalds int (*check_acl)(struct inode *inode, int mask)) 2141da177e4SLinus Torvalds { 2155909ccaaSLinus Torvalds int ret; 2161da177e4SLinus Torvalds 2171da177e4SLinus Torvalds /* 2185909ccaaSLinus Torvalds * Do the basic POSIX ACL permission checks. 2191da177e4SLinus Torvalds */ 2205909ccaaSLinus Torvalds ret = acl_permission_check(inode, mask, check_acl); 2215909ccaaSLinus Torvalds if (ret != -EACCES) 2225909ccaaSLinus Torvalds return ret; 2231da177e4SLinus Torvalds 2241da177e4SLinus Torvalds /* 2251da177e4SLinus Torvalds * Read/write DACs are always overridable. 2261da177e4SLinus Torvalds * Executable DACs are overridable if at least one exec bit is set. 2271da177e4SLinus Torvalds */ 228f696a365SMiklos Szeredi if (!(mask & MAY_EXEC) || execute_ok(inode)) 2291da177e4SLinus Torvalds if (capable(CAP_DAC_OVERRIDE)) 2301da177e4SLinus Torvalds return 0; 2311da177e4SLinus Torvalds 2321da177e4SLinus Torvalds /* 2331da177e4SLinus Torvalds * Searching includes executable on directories, else just read. 2341da177e4SLinus Torvalds */ 2351da177e4SLinus Torvalds if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) 2361da177e4SLinus Torvalds if (capable(CAP_DAC_READ_SEARCH)) 2371da177e4SLinus Torvalds return 0; 2381da177e4SLinus Torvalds 2391da177e4SLinus Torvalds return -EACCES; 2401da177e4SLinus Torvalds } 2411da177e4SLinus Torvalds 242cb23beb5SChristoph Hellwig /** 243cb23beb5SChristoph Hellwig * inode_permission - check for access rights to a given inode 244cb23beb5SChristoph Hellwig * @inode: inode to check permission on 245cb23beb5SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 246cb23beb5SChristoph Hellwig * 247cb23beb5SChristoph Hellwig * Used to check for read/write/execute permissions on an inode. 248cb23beb5SChristoph Hellwig * We use "fsuid" for this, letting us set arbitrary permissions 249cb23beb5SChristoph Hellwig * for filesystem access without changing the "normal" uids which 250cb23beb5SChristoph Hellwig * are used for other things. 251cb23beb5SChristoph Hellwig */ 252f419a2e3SAl Viro int inode_permission(struct inode *inode, int mask) 2531da177e4SLinus Torvalds { 254e6305c43SAl Viro int retval; 2551da177e4SLinus Torvalds 2561da177e4SLinus Torvalds if (mask & MAY_WRITE) { 25722590e41SMiklos Szeredi umode_t mode = inode->i_mode; 2581da177e4SLinus Torvalds 2591da177e4SLinus Torvalds /* 2601da177e4SLinus Torvalds * Nobody gets write access to a read-only fs. 2611da177e4SLinus Torvalds */ 2621da177e4SLinus Torvalds if (IS_RDONLY(inode) && 2631da177e4SLinus Torvalds (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) 2641da177e4SLinus Torvalds return -EROFS; 2651da177e4SLinus Torvalds 2661da177e4SLinus Torvalds /* 2671da177e4SLinus Torvalds * Nobody gets write access to an immutable file. 2681da177e4SLinus Torvalds */ 2691da177e4SLinus Torvalds if (IS_IMMUTABLE(inode)) 2701da177e4SLinus Torvalds return -EACCES; 2711da177e4SLinus Torvalds } 2721da177e4SLinus Torvalds 273acfa4380SAl Viro if (inode->i_op->permission) 274b77b0646SAl Viro retval = inode->i_op->permission(inode, mask); 275f696a365SMiklos Szeredi else 2765909ccaaSLinus Torvalds retval = generic_permission(inode, mask, inode->i_op->check_acl); 277f696a365SMiklos Szeredi 2781da177e4SLinus Torvalds if (retval) 2791da177e4SLinus Torvalds return retval; 2801da177e4SLinus Torvalds 28108ce5f16SSerge E. Hallyn retval = devcgroup_inode_permission(inode, mask); 28208ce5f16SSerge E. Hallyn if (retval) 28308ce5f16SSerge E. Hallyn return retval; 28408ce5f16SSerge E. Hallyn 285e6305c43SAl Viro return security_inode_permission(inode, 286f418b006SStephen Smalley mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)); 2871da177e4SLinus Torvalds } 2881da177e4SLinus Torvalds 289e4543eddSChristoph Hellwig /** 2908c744fb8SChristoph Hellwig * file_permission - check for additional access rights to a given file 2918c744fb8SChristoph Hellwig * @file: file to check access rights for 2928c744fb8SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 2938c744fb8SChristoph Hellwig * 2948c744fb8SChristoph Hellwig * Used to check for read/write/execute permissions on an already opened 2958c744fb8SChristoph Hellwig * file. 2968c744fb8SChristoph Hellwig * 2978c744fb8SChristoph Hellwig * Note: 2988c744fb8SChristoph Hellwig * Do not use this function in new code. All access checks should 299cb23beb5SChristoph Hellwig * be done using inode_permission(). 3008c744fb8SChristoph Hellwig */ 3018c744fb8SChristoph Hellwig int file_permission(struct file *file, int mask) 3028c744fb8SChristoph Hellwig { 303f419a2e3SAl Viro return inode_permission(file->f_path.dentry->d_inode, mask); 3048c744fb8SChristoph Hellwig } 3058c744fb8SChristoph Hellwig 3061da177e4SLinus Torvalds /* 3071da177e4SLinus Torvalds * get_write_access() gets write permission for a file. 3081da177e4SLinus Torvalds * put_write_access() releases this write permission. 3091da177e4SLinus Torvalds * This is used for regular files. 3101da177e4SLinus Torvalds * We cannot support write (and maybe mmap read-write shared) accesses and 3111da177e4SLinus Torvalds * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode 3121da177e4SLinus Torvalds * can have the following values: 3131da177e4SLinus Torvalds * 0: no writers, no VM_DENYWRITE mappings 3141da177e4SLinus Torvalds * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist 3151da177e4SLinus Torvalds * > 0: (i_writecount) users are writing to the file. 3161da177e4SLinus Torvalds * 3171da177e4SLinus Torvalds * Normally we operate on that counter with atomic_{inc,dec} and it's safe 3181da177e4SLinus Torvalds * except for the cases where we don't hold i_writecount yet. Then we need to 3191da177e4SLinus Torvalds * use {get,deny}_write_access() - these functions check the sign and refuse 3201da177e4SLinus Torvalds * to do the change if sign is wrong. Exclusion between them is provided by 3211da177e4SLinus Torvalds * the inode->i_lock spinlock. 3221da177e4SLinus Torvalds */ 3231da177e4SLinus Torvalds 3241da177e4SLinus Torvalds int get_write_access(struct inode * inode) 3251da177e4SLinus Torvalds { 3261da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3271da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) < 0) { 3281da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3291da177e4SLinus Torvalds return -ETXTBSY; 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 3321da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3331da177e4SLinus Torvalds 3341da177e4SLinus Torvalds return 0; 3351da177e4SLinus Torvalds } 3361da177e4SLinus Torvalds 3371da177e4SLinus Torvalds int deny_write_access(struct file * file) 3381da177e4SLinus Torvalds { 3390f7fc9e4SJosef "Jeff" Sipek struct inode *inode = file->f_path.dentry->d_inode; 3401da177e4SLinus Torvalds 3411da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3421da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) > 0) { 3431da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3441da177e4SLinus Torvalds return -ETXTBSY; 3451da177e4SLinus Torvalds } 3461da177e4SLinus Torvalds atomic_dec(&inode->i_writecount); 3471da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3481da177e4SLinus Torvalds 3491da177e4SLinus Torvalds return 0; 3501da177e4SLinus Torvalds } 3511da177e4SLinus Torvalds 3521d957f9bSJan Blunck /** 3535dd784d0SJan Blunck * path_get - get a reference to a path 3545dd784d0SJan Blunck * @path: path to get the reference to 3555dd784d0SJan Blunck * 3565dd784d0SJan Blunck * Given a path increment the reference count to the dentry and the vfsmount. 3575dd784d0SJan Blunck */ 3585dd784d0SJan Blunck void path_get(struct path *path) 3595dd784d0SJan Blunck { 3605dd784d0SJan Blunck mntget(path->mnt); 3615dd784d0SJan Blunck dget(path->dentry); 3625dd784d0SJan Blunck } 3635dd784d0SJan Blunck EXPORT_SYMBOL(path_get); 3645dd784d0SJan Blunck 3655dd784d0SJan Blunck /** 3661d957f9bSJan Blunck * path_put - put a reference to a path 3671d957f9bSJan Blunck * @path: path to put the reference to 3681d957f9bSJan Blunck * 3691d957f9bSJan Blunck * Given a path decrement the reference count to the dentry and the vfsmount. 3701d957f9bSJan Blunck */ 3711d957f9bSJan Blunck void path_put(struct path *path) 3721da177e4SLinus Torvalds { 3731d957f9bSJan Blunck dput(path->dentry); 3741d957f9bSJan Blunck mntput(path->mnt); 3751da177e4SLinus Torvalds } 3761d957f9bSJan Blunck EXPORT_SYMBOL(path_put); 3771da177e4SLinus Torvalds 378834f2a4aSTrond Myklebust /** 379834f2a4aSTrond Myklebust * release_open_intent - free up open intent resources 380834f2a4aSTrond Myklebust * @nd: pointer to nameidata 381834f2a4aSTrond Myklebust */ 382834f2a4aSTrond Myklebust void release_open_intent(struct nameidata *nd) 383834f2a4aSTrond Myklebust { 3840f7fc9e4SJosef "Jeff" Sipek if (nd->intent.open.file->f_path.dentry == NULL) 385834f2a4aSTrond Myklebust put_filp(nd->intent.open.file); 386834f2a4aSTrond Myklebust else 387834f2a4aSTrond Myklebust fput(nd->intent.open.file); 388834f2a4aSTrond Myklebust } 389834f2a4aSTrond Myklebust 390bcdc5e01SIan Kent static inline struct dentry * 391bcdc5e01SIan Kent do_revalidate(struct dentry *dentry, struct nameidata *nd) 392bcdc5e01SIan Kent { 393bcdc5e01SIan Kent int status = dentry->d_op->d_revalidate(dentry, nd); 394bcdc5e01SIan Kent if (unlikely(status <= 0)) { 395bcdc5e01SIan Kent /* 396bcdc5e01SIan Kent * The dentry failed validation. 397bcdc5e01SIan Kent * If d_revalidate returned 0 attempt to invalidate 398bcdc5e01SIan Kent * the dentry otherwise d_revalidate is asking us 399bcdc5e01SIan Kent * to return a fail status. 400bcdc5e01SIan Kent */ 401bcdc5e01SIan Kent if (!status) { 402bcdc5e01SIan Kent if (!d_invalidate(dentry)) { 403bcdc5e01SIan Kent dput(dentry); 404bcdc5e01SIan Kent dentry = NULL; 405bcdc5e01SIan Kent } 406bcdc5e01SIan Kent } else { 407bcdc5e01SIan Kent dput(dentry); 408bcdc5e01SIan Kent dentry = ERR_PTR(status); 409bcdc5e01SIan Kent } 410bcdc5e01SIan Kent } 411bcdc5e01SIan Kent return dentry; 412bcdc5e01SIan Kent } 413bcdc5e01SIan Kent 4141da177e4SLinus Torvalds /* 4151da177e4SLinus Torvalds * Internal lookup() using the new generic dcache. 4161da177e4SLinus Torvalds * SMP-safe 4171da177e4SLinus Torvalds */ 4181da177e4SLinus Torvalds static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4191da177e4SLinus Torvalds { 4201da177e4SLinus Torvalds struct dentry * dentry = __d_lookup(parent, name); 4211da177e4SLinus Torvalds 4221da177e4SLinus Torvalds /* lockess __d_lookup may fail due to concurrent d_move() 4231da177e4SLinus Torvalds * in some unrelated directory, so try with d_lookup 4241da177e4SLinus Torvalds */ 4251da177e4SLinus Torvalds if (!dentry) 4261da177e4SLinus Torvalds dentry = d_lookup(parent, name); 4271da177e4SLinus Torvalds 428bcdc5e01SIan Kent if (dentry && dentry->d_op && dentry->d_op->d_revalidate) 429bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 430bcdc5e01SIan Kent 4311da177e4SLinus Torvalds return dentry; 4321da177e4SLinus Torvalds } 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds /* 4351da177e4SLinus Torvalds * Short-cut version of permission(), for calling by 4361da177e4SLinus Torvalds * path_walk(), when dcache lock is held. Combines parts 4371da177e4SLinus Torvalds * of permission() and generic_permission(), and tests ONLY for 4381da177e4SLinus Torvalds * MAY_EXEC permission. 4391da177e4SLinus Torvalds * 4401da177e4SLinus Torvalds * If appropriate, check DAC only. If not appropriate, or 4411da177e4SLinus Torvalds * short-cut DAC fails, then call permission() to do more 4421da177e4SLinus Torvalds * complete permission check. 4431da177e4SLinus Torvalds */ 444672b16b2SAl Viro static int exec_permission_lite(struct inode *inode) 4451da177e4SLinus Torvalds { 4465909ccaaSLinus Torvalds int ret; 4471da177e4SLinus Torvalds 448cb9179eaSLinus Torvalds if (inode->i_op->permission) { 4495909ccaaSLinus Torvalds ret = inode->i_op->permission(inode, MAY_EXEC); 450cb9179eaSLinus Torvalds if (!ret) 451cb9179eaSLinus Torvalds goto ok; 452cb9179eaSLinus Torvalds return ret; 453cb9179eaSLinus Torvalds } 4545909ccaaSLinus Torvalds ret = acl_permission_check(inode, MAY_EXEC, inode->i_op->check_acl); 4555909ccaaSLinus Torvalds if (!ret) 4561da177e4SLinus Torvalds goto ok; 4571da177e4SLinus Torvalds 458f1ac9f6bSLinus Torvalds if (capable(CAP_DAC_OVERRIDE) || capable(CAP_DAC_READ_SEARCH)) 4591da177e4SLinus Torvalds goto ok; 4601da177e4SLinus Torvalds 4615909ccaaSLinus Torvalds return ret; 4621da177e4SLinus Torvalds ok: 463b77b0646SAl Viro return security_inode_permission(inode, MAY_EXEC); 4641da177e4SLinus Torvalds } 4651da177e4SLinus Torvalds 4661da177e4SLinus Torvalds /* 4671da177e4SLinus Torvalds * This is called when everything else fails, and we actually have 4681da177e4SLinus Torvalds * to go to the low-level filesystem to find out what we should do.. 4691da177e4SLinus Torvalds * 4701da177e4SLinus Torvalds * We get the directory semaphore, and after getting that we also 4711da177e4SLinus Torvalds * make sure that nobody added the entry to the dcache in the meantime.. 4721da177e4SLinus Torvalds * SMP-safe 4731da177e4SLinus Torvalds */ 4741da177e4SLinus Torvalds static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4751da177e4SLinus Torvalds { 4761da177e4SLinus Torvalds struct dentry * result; 4771da177e4SLinus Torvalds struct inode *dir = parent->d_inode; 4781da177e4SLinus Torvalds 4791b1dcc1bSJes Sorensen mutex_lock(&dir->i_mutex); 4801da177e4SLinus Torvalds /* 4811da177e4SLinus Torvalds * First re-do the cached lookup just in case it was created 4821da177e4SLinus Torvalds * while we waited for the directory semaphore.. 4831da177e4SLinus Torvalds * 4841da177e4SLinus Torvalds * FIXME! This could use version numbering or similar to 4851da177e4SLinus Torvalds * avoid unnecessary cache lookups. 4861da177e4SLinus Torvalds * 4871da177e4SLinus Torvalds * The "dcache_lock" is purely to protect the RCU list walker 4881da177e4SLinus Torvalds * from concurrent renames at this point (we mustn't get false 4891da177e4SLinus Torvalds * negatives from the RCU list walk here, unlike the optimistic 4901da177e4SLinus Torvalds * fast walk). 4911da177e4SLinus Torvalds * 4921da177e4SLinus Torvalds * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup 4931da177e4SLinus Torvalds */ 4941da177e4SLinus Torvalds result = d_lookup(parent, name); 4951da177e4SLinus Torvalds if (!result) { 496d70b67c8SMiklos Szeredi struct dentry *dentry; 497d70b67c8SMiklos Szeredi 498d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 499d70b67c8SMiklos Szeredi result = ERR_PTR(-ENOENT); 500d70b67c8SMiklos Szeredi if (IS_DEADDIR(dir)) 501d70b67c8SMiklos Szeredi goto out_unlock; 502d70b67c8SMiklos Szeredi 503d70b67c8SMiklos Szeredi dentry = d_alloc(parent, name); 5041da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 5051da177e4SLinus Torvalds if (dentry) { 5061da177e4SLinus Torvalds result = dir->i_op->lookup(dir, dentry, nd); 5071da177e4SLinus Torvalds if (result) 5081da177e4SLinus Torvalds dput(dentry); 5091da177e4SLinus Torvalds else 5101da177e4SLinus Torvalds result = dentry; 5111da177e4SLinus Torvalds } 512d70b67c8SMiklos Szeredi out_unlock: 5131b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5141da177e4SLinus Torvalds return result; 5151da177e4SLinus Torvalds } 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds /* 5181da177e4SLinus Torvalds * Uhhuh! Nasty case: the cache was re-populated while 5191da177e4SLinus Torvalds * we waited on the semaphore. Need to revalidate. 5201da177e4SLinus Torvalds */ 5211b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5221da177e4SLinus Torvalds if (result->d_op && result->d_op->d_revalidate) { 523bcdc5e01SIan Kent result = do_revalidate(result, nd); 524bcdc5e01SIan Kent if (!result) 5251da177e4SLinus Torvalds result = ERR_PTR(-ENOENT); 5261da177e4SLinus Torvalds } 5271da177e4SLinus Torvalds return result; 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds 5302a737871SAl Viro static __always_inline void set_root(struct nameidata *nd) 5312a737871SAl Viro { 5322a737871SAl Viro if (!nd->root.mnt) { 5332a737871SAl Viro struct fs_struct *fs = current->fs; 5342a737871SAl Viro read_lock(&fs->lock); 5352a737871SAl Viro nd->root = fs->root; 5362a737871SAl Viro path_get(&nd->root); 5372a737871SAl Viro read_unlock(&fs->lock); 5382a737871SAl Viro } 5392a737871SAl Viro } 5402a737871SAl Viro 5416de88d72SAl Viro static int link_path_walk(const char *, struct nameidata *); 5426de88d72SAl Viro 543f1662356SArjan van de Ven static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) 5441da177e4SLinus Torvalds { 5451da177e4SLinus Torvalds int res = 0; 5461da177e4SLinus Torvalds char *name; 5471da177e4SLinus Torvalds if (IS_ERR(link)) 5481da177e4SLinus Torvalds goto fail; 5491da177e4SLinus Torvalds 5501da177e4SLinus Torvalds if (*link == '/') { 5512a737871SAl Viro set_root(nd); 5521d957f9bSJan Blunck path_put(&nd->path); 5532a737871SAl Viro nd->path = nd->root; 5542a737871SAl Viro path_get(&nd->root); 5551da177e4SLinus Torvalds } 556b4091d5fSChristoph Hellwig 5571da177e4SLinus Torvalds res = link_path_walk(link, nd); 5581da177e4SLinus Torvalds if (nd->depth || res || nd->last_type!=LAST_NORM) 5591da177e4SLinus Torvalds return res; 5601da177e4SLinus Torvalds /* 5611da177e4SLinus Torvalds * If it is an iterative symlinks resolution in open_namei() we 5621da177e4SLinus Torvalds * have to copy the last component. And all that crap because of 5631da177e4SLinus Torvalds * bloody create() on broken symlinks. Furrfu... 5641da177e4SLinus Torvalds */ 5651da177e4SLinus Torvalds name = __getname(); 5661da177e4SLinus Torvalds if (unlikely(!name)) { 5671d957f9bSJan Blunck path_put(&nd->path); 5681da177e4SLinus Torvalds return -ENOMEM; 5691da177e4SLinus Torvalds } 5701da177e4SLinus Torvalds strcpy(name, nd->last.name); 5711da177e4SLinus Torvalds nd->last.name = name; 5721da177e4SLinus Torvalds return 0; 5731da177e4SLinus Torvalds fail: 5741d957f9bSJan Blunck path_put(&nd->path); 5751da177e4SLinus Torvalds return PTR_ERR(link); 5761da177e4SLinus Torvalds } 5771da177e4SLinus Torvalds 5781d957f9bSJan Blunck static void path_put_conditional(struct path *path, struct nameidata *nd) 579051d3812SIan Kent { 580051d3812SIan Kent dput(path->dentry); 5814ac91378SJan Blunck if (path->mnt != nd->path.mnt) 582051d3812SIan Kent mntput(path->mnt); 583051d3812SIan Kent } 584051d3812SIan Kent 585051d3812SIan Kent static inline void path_to_nameidata(struct path *path, struct nameidata *nd) 586051d3812SIan Kent { 5874ac91378SJan Blunck dput(nd->path.dentry); 5884ac91378SJan Blunck if (nd->path.mnt != path->mnt) 5894ac91378SJan Blunck mntput(nd->path.mnt); 5904ac91378SJan Blunck nd->path.mnt = path->mnt; 5914ac91378SJan Blunck nd->path.dentry = path->dentry; 592051d3812SIan Kent } 593051d3812SIan Kent 594f1662356SArjan van de Ven static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) 5951da177e4SLinus Torvalds { 5961da177e4SLinus Torvalds int error; 597cc314eefSLinus Torvalds void *cookie; 598cd4e91d3SAl Viro struct dentry *dentry = path->dentry; 5991da177e4SLinus Torvalds 600d671a1cbSAl Viro touch_atime(path->mnt, dentry); 6011da177e4SLinus Torvalds nd_set_link(nd, NULL); 602cd4e91d3SAl Viro 6034ac91378SJan Blunck if (path->mnt != nd->path.mnt) { 604051d3812SIan Kent path_to_nameidata(path, nd); 605051d3812SIan Kent dget(dentry); 606051d3812SIan Kent } 607cd4e91d3SAl Viro mntget(path->mnt); 608cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, nd); 609cc314eefSLinus Torvalds error = PTR_ERR(cookie); 610cc314eefSLinus Torvalds if (!IS_ERR(cookie)) { 6111da177e4SLinus Torvalds char *s = nd_get_link(nd); 612cc314eefSLinus Torvalds error = 0; 6131da177e4SLinus Torvalds if (s) 6141da177e4SLinus Torvalds error = __vfs_follow_link(nd, s); 6151da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 616cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, nd, cookie); 6171da177e4SLinus Torvalds } 6181da177e4SLinus Torvalds return error; 6191da177e4SLinus Torvalds } 6201da177e4SLinus Torvalds 6211da177e4SLinus Torvalds /* 6221da177e4SLinus Torvalds * This limits recursive symlink follows to 8, while 6231da177e4SLinus Torvalds * limiting consecutive symlinks to 40. 6241da177e4SLinus Torvalds * 6251da177e4SLinus Torvalds * Without that kind of total limit, nasty chains of consecutive 6261da177e4SLinus Torvalds * symlinks can cause almost arbitrarily long lookups. 6271da177e4SLinus Torvalds */ 62890ebe565SAl Viro static inline int do_follow_link(struct path *path, struct nameidata *nd) 6291da177e4SLinus Torvalds { 6301da177e4SLinus Torvalds int err = -ELOOP; 6311da177e4SLinus Torvalds if (current->link_count >= MAX_NESTED_LINKS) 6321da177e4SLinus Torvalds goto loop; 6331da177e4SLinus Torvalds if (current->total_link_count >= 40) 6341da177e4SLinus Torvalds goto loop; 6351da177e4SLinus Torvalds BUG_ON(nd->depth >= MAX_NESTED_LINKS); 6361da177e4SLinus Torvalds cond_resched(); 63790ebe565SAl Viro err = security_inode_follow_link(path->dentry, nd); 6381da177e4SLinus Torvalds if (err) 6391da177e4SLinus Torvalds goto loop; 6401da177e4SLinus Torvalds current->link_count++; 6411da177e4SLinus Torvalds current->total_link_count++; 6421da177e4SLinus Torvalds nd->depth++; 643cd4e91d3SAl Viro err = __do_follow_link(path, nd); 644258fa999SAl Viro path_put(path); 6451da177e4SLinus Torvalds current->link_count--; 6461da177e4SLinus Torvalds nd->depth--; 6471da177e4SLinus Torvalds return err; 6481da177e4SLinus Torvalds loop: 6491d957f9bSJan Blunck path_put_conditional(path, nd); 6501d957f9bSJan Blunck path_put(&nd->path); 6511da177e4SLinus Torvalds return err; 6521da177e4SLinus Torvalds } 6531da177e4SLinus Torvalds 654bab77ebfSAl Viro int follow_up(struct path *path) 6551da177e4SLinus Torvalds { 6561da177e4SLinus Torvalds struct vfsmount *parent; 6571da177e4SLinus Torvalds struct dentry *mountpoint; 6581da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 659bab77ebfSAl Viro parent = path->mnt->mnt_parent; 660bab77ebfSAl Viro if (parent == path->mnt) { 6611da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6621da177e4SLinus Torvalds return 0; 6631da177e4SLinus Torvalds } 6641da177e4SLinus Torvalds mntget(parent); 665bab77ebfSAl Viro mountpoint = dget(path->mnt->mnt_mountpoint); 6661da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 667bab77ebfSAl Viro dput(path->dentry); 668bab77ebfSAl Viro path->dentry = mountpoint; 669bab77ebfSAl Viro mntput(path->mnt); 670bab77ebfSAl Viro path->mnt = parent; 6711da177e4SLinus Torvalds return 1; 6721da177e4SLinus Torvalds } 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 6751da177e4SLinus Torvalds * namespace.c 6761da177e4SLinus Torvalds */ 677463ffb2eSAl Viro static int __follow_mount(struct path *path) 678463ffb2eSAl Viro { 679463ffb2eSAl Viro int res = 0; 680463ffb2eSAl Viro while (d_mountpoint(path->dentry)) { 6811c755af4SAl Viro struct vfsmount *mounted = lookup_mnt(path); 682463ffb2eSAl Viro if (!mounted) 683463ffb2eSAl Viro break; 684463ffb2eSAl Viro dput(path->dentry); 685463ffb2eSAl Viro if (res) 686463ffb2eSAl Viro mntput(path->mnt); 687463ffb2eSAl Viro path->mnt = mounted; 688463ffb2eSAl Viro path->dentry = dget(mounted->mnt_root); 689463ffb2eSAl Viro res = 1; 690463ffb2eSAl Viro } 691463ffb2eSAl Viro return res; 692463ffb2eSAl Viro } 693463ffb2eSAl Viro 69479ed0226SAl Viro static void follow_mount(struct path *path) 6951da177e4SLinus Torvalds { 69679ed0226SAl Viro while (d_mountpoint(path->dentry)) { 6971c755af4SAl Viro struct vfsmount *mounted = lookup_mnt(path); 6981da177e4SLinus Torvalds if (!mounted) 6991da177e4SLinus Torvalds break; 70079ed0226SAl Viro dput(path->dentry); 70179ed0226SAl Viro mntput(path->mnt); 70279ed0226SAl Viro path->mnt = mounted; 70379ed0226SAl Viro path->dentry = dget(mounted->mnt_root); 7041da177e4SLinus Torvalds } 7051da177e4SLinus Torvalds } 7061da177e4SLinus Torvalds 7071da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 7081da177e4SLinus Torvalds * namespace.c 7091da177e4SLinus Torvalds */ 7109393bd07SAl Viro int follow_down(struct path *path) 7111da177e4SLinus Torvalds { 7121da177e4SLinus Torvalds struct vfsmount *mounted; 7131da177e4SLinus Torvalds 7141c755af4SAl Viro mounted = lookup_mnt(path); 7151da177e4SLinus Torvalds if (mounted) { 7169393bd07SAl Viro dput(path->dentry); 7179393bd07SAl Viro mntput(path->mnt); 7189393bd07SAl Viro path->mnt = mounted; 7199393bd07SAl Viro path->dentry = dget(mounted->mnt_root); 7201da177e4SLinus Torvalds return 1; 7211da177e4SLinus Torvalds } 7221da177e4SLinus Torvalds return 0; 7231da177e4SLinus Torvalds } 7241da177e4SLinus Torvalds 725f1662356SArjan van de Ven static __always_inline void follow_dotdot(struct nameidata *nd) 7261da177e4SLinus Torvalds { 7272a737871SAl Viro set_root(nd); 728e518ddb7SAndreas Mohr 7291da177e4SLinus Torvalds while(1) { 7301da177e4SLinus Torvalds struct vfsmount *parent; 7314ac91378SJan Blunck struct dentry *old = nd->path.dentry; 7321da177e4SLinus Torvalds 7332a737871SAl Viro if (nd->path.dentry == nd->root.dentry && 7342a737871SAl Viro nd->path.mnt == nd->root.mnt) { 7351da177e4SLinus Torvalds break; 7361da177e4SLinus Torvalds } 7371da177e4SLinus Torvalds spin_lock(&dcache_lock); 7384ac91378SJan Blunck if (nd->path.dentry != nd->path.mnt->mnt_root) { 7394ac91378SJan Blunck nd->path.dentry = dget(nd->path.dentry->d_parent); 7401da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7411da177e4SLinus Torvalds dput(old); 7421da177e4SLinus Torvalds break; 7431da177e4SLinus Torvalds } 7441da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7451da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 7464ac91378SJan Blunck parent = nd->path.mnt->mnt_parent; 7474ac91378SJan Blunck if (parent == nd->path.mnt) { 7481da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7491da177e4SLinus Torvalds break; 7501da177e4SLinus Torvalds } 7511da177e4SLinus Torvalds mntget(parent); 7524ac91378SJan Blunck nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); 7531da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7541da177e4SLinus Torvalds dput(old); 7554ac91378SJan Blunck mntput(nd->path.mnt); 7564ac91378SJan Blunck nd->path.mnt = parent; 7571da177e4SLinus Torvalds } 75879ed0226SAl Viro follow_mount(&nd->path); 7591da177e4SLinus Torvalds } 7601da177e4SLinus Torvalds 7611da177e4SLinus Torvalds /* 7621da177e4SLinus Torvalds * It's more convoluted than I'd like it to be, but... it's still fairly 7631da177e4SLinus Torvalds * small and for now I'd prefer to have fast path as straight as possible. 7641da177e4SLinus Torvalds * It _is_ time-critical. 7651da177e4SLinus Torvalds */ 7661da177e4SLinus Torvalds static int do_lookup(struct nameidata *nd, struct qstr *name, 7671da177e4SLinus Torvalds struct path *path) 7681da177e4SLinus Torvalds { 7694ac91378SJan Blunck struct vfsmount *mnt = nd->path.mnt; 7703cac260aSAl Viro struct dentry *dentry; 7713cac260aSAl Viro /* 7723cac260aSAl Viro * See if the low-level filesystem might want 7733cac260aSAl Viro * to use its own hash.. 7743cac260aSAl Viro */ 7753cac260aSAl Viro if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 7763cac260aSAl Viro int err = nd->path.dentry->d_op->d_hash(nd->path.dentry, name); 7773cac260aSAl Viro if (err < 0) 7783cac260aSAl Viro return err; 7793cac260aSAl Viro } 7801da177e4SLinus Torvalds 7813cac260aSAl Viro dentry = __d_lookup(nd->path.dentry, name); 7821da177e4SLinus Torvalds if (!dentry) 7831da177e4SLinus Torvalds goto need_lookup; 7841da177e4SLinus Torvalds if (dentry->d_op && dentry->d_op->d_revalidate) 7851da177e4SLinus Torvalds goto need_revalidate; 7861da177e4SLinus Torvalds done: 7871da177e4SLinus Torvalds path->mnt = mnt; 7881da177e4SLinus Torvalds path->dentry = dentry; 789634ee701SAl Viro __follow_mount(path); 7901da177e4SLinus Torvalds return 0; 7911da177e4SLinus Torvalds 7921da177e4SLinus Torvalds need_lookup: 7934ac91378SJan Blunck dentry = real_lookup(nd->path.dentry, name, nd); 7941da177e4SLinus Torvalds if (IS_ERR(dentry)) 7951da177e4SLinus Torvalds goto fail; 7961da177e4SLinus Torvalds goto done; 7971da177e4SLinus Torvalds 7981da177e4SLinus Torvalds need_revalidate: 799bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 800bcdc5e01SIan Kent if (!dentry) 8011da177e4SLinus Torvalds goto need_lookup; 802bcdc5e01SIan Kent if (IS_ERR(dentry)) 803bcdc5e01SIan Kent goto fail; 804bcdc5e01SIan Kent goto done; 8051da177e4SLinus Torvalds 8061da177e4SLinus Torvalds fail: 8071da177e4SLinus Torvalds return PTR_ERR(dentry); 8081da177e4SLinus Torvalds } 8091da177e4SLinus Torvalds 8101da177e4SLinus Torvalds /* 8111da177e4SLinus Torvalds * Name resolution. 812ea3834d9SPrasanna Meda * This is the basic name resolution function, turning a pathname into 813ea3834d9SPrasanna Meda * the final dentry. We expect 'base' to be positive and a directory. 8141da177e4SLinus Torvalds * 815ea3834d9SPrasanna Meda * Returns 0 and nd will have valid dentry and mnt on success. 816ea3834d9SPrasanna Meda * Returns error and drops reference to input namei data on failure. 8171da177e4SLinus Torvalds */ 8186de88d72SAl Viro static int link_path_walk(const char *name, struct nameidata *nd) 8191da177e4SLinus Torvalds { 8201da177e4SLinus Torvalds struct path next; 8211da177e4SLinus Torvalds struct inode *inode; 8221da177e4SLinus Torvalds int err; 8231da177e4SLinus Torvalds unsigned int lookup_flags = nd->flags; 8241da177e4SLinus Torvalds 8251da177e4SLinus Torvalds while (*name=='/') 8261da177e4SLinus Torvalds name++; 8271da177e4SLinus Torvalds if (!*name) 8281da177e4SLinus Torvalds goto return_reval; 8291da177e4SLinus Torvalds 8304ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8311da177e4SLinus Torvalds if (nd->depth) 832f55eab82STrond Myklebust lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); 8331da177e4SLinus Torvalds 8341da177e4SLinus Torvalds /* At this point we know we have a real path component. */ 8351da177e4SLinus Torvalds for(;;) { 8361da177e4SLinus Torvalds unsigned long hash; 8371da177e4SLinus Torvalds struct qstr this; 8381da177e4SLinus Torvalds unsigned int c; 8391da177e4SLinus Torvalds 840cdce5d6bSTrond Myklebust nd->flags |= LOOKUP_CONTINUE; 841672b16b2SAl Viro err = exec_permission_lite(inode); 8421da177e4SLinus Torvalds if (err) 8431da177e4SLinus Torvalds break; 8441da177e4SLinus Torvalds 8451da177e4SLinus Torvalds this.name = name; 8461da177e4SLinus Torvalds c = *(const unsigned char *)name; 8471da177e4SLinus Torvalds 8481da177e4SLinus Torvalds hash = init_name_hash(); 8491da177e4SLinus Torvalds do { 8501da177e4SLinus Torvalds name++; 8511da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 8521da177e4SLinus Torvalds c = *(const unsigned char *)name; 8531da177e4SLinus Torvalds } while (c && (c != '/')); 8541da177e4SLinus Torvalds this.len = name - (const char *) this.name; 8551da177e4SLinus Torvalds this.hash = end_name_hash(hash); 8561da177e4SLinus Torvalds 8571da177e4SLinus Torvalds /* remove trailing slashes? */ 8581da177e4SLinus Torvalds if (!c) 8591da177e4SLinus Torvalds goto last_component; 8601da177e4SLinus Torvalds while (*++name == '/'); 8611da177e4SLinus Torvalds if (!*name) 8621da177e4SLinus Torvalds goto last_with_slashes; 8631da177e4SLinus Torvalds 8641da177e4SLinus Torvalds /* 8651da177e4SLinus Torvalds * "." and ".." are special - ".." especially so because it has 8661da177e4SLinus Torvalds * to be able to know about the current root directory and 8671da177e4SLinus Torvalds * parent relationships. 8681da177e4SLinus Torvalds */ 8691da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 8701da177e4SLinus Torvalds default: 8711da177e4SLinus Torvalds break; 8721da177e4SLinus Torvalds case 2: 8731da177e4SLinus Torvalds if (this.name[1] != '.') 8741da177e4SLinus Torvalds break; 87558c465ebSAl Viro follow_dotdot(nd); 8764ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8771da177e4SLinus Torvalds /* fallthrough */ 8781da177e4SLinus Torvalds case 1: 8791da177e4SLinus Torvalds continue; 8801da177e4SLinus Torvalds } 8811da177e4SLinus Torvalds /* This does the actual lookups.. */ 8821da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 8831da177e4SLinus Torvalds if (err) 8841da177e4SLinus Torvalds break; 8851da177e4SLinus Torvalds 8861da177e4SLinus Torvalds err = -ENOENT; 8871da177e4SLinus Torvalds inode = next.dentry->d_inode; 8881da177e4SLinus Torvalds if (!inode) 8891da177e4SLinus Torvalds goto out_dput; 8901da177e4SLinus Torvalds 8911da177e4SLinus Torvalds if (inode->i_op->follow_link) { 89290ebe565SAl Viro err = do_follow_link(&next, nd); 8931da177e4SLinus Torvalds if (err) 8941da177e4SLinus Torvalds goto return_err; 8951da177e4SLinus Torvalds err = -ENOENT; 8964ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8971da177e4SLinus Torvalds if (!inode) 8981da177e4SLinus Torvalds break; 89909dd17d3SMiklos Szeredi } else 90009dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9011da177e4SLinus Torvalds err = -ENOTDIR; 9021da177e4SLinus Torvalds if (!inode->i_op->lookup) 9031da177e4SLinus Torvalds break; 9041da177e4SLinus Torvalds continue; 9051da177e4SLinus Torvalds /* here ends the main loop */ 9061da177e4SLinus Torvalds 9071da177e4SLinus Torvalds last_with_slashes: 9081da177e4SLinus Torvalds lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 9091da177e4SLinus Torvalds last_component: 910f55eab82STrond Myklebust /* Clear LOOKUP_CONTINUE iff it was previously unset */ 911f55eab82STrond Myklebust nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; 9121da177e4SLinus Torvalds if (lookup_flags & LOOKUP_PARENT) 9131da177e4SLinus Torvalds goto lookup_parent; 9141da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 9151da177e4SLinus Torvalds default: 9161da177e4SLinus Torvalds break; 9171da177e4SLinus Torvalds case 2: 9181da177e4SLinus Torvalds if (this.name[1] != '.') 9191da177e4SLinus Torvalds break; 92058c465ebSAl Viro follow_dotdot(nd); 9214ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9221da177e4SLinus Torvalds /* fallthrough */ 9231da177e4SLinus Torvalds case 1: 9241da177e4SLinus Torvalds goto return_reval; 9251da177e4SLinus Torvalds } 9261da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9271da177e4SLinus Torvalds if (err) 9281da177e4SLinus Torvalds break; 9291da177e4SLinus Torvalds inode = next.dentry->d_inode; 9301da177e4SLinus Torvalds if ((lookup_flags & LOOKUP_FOLLOW) 931acfa4380SAl Viro && inode && inode->i_op->follow_link) { 93290ebe565SAl Viro err = do_follow_link(&next, nd); 9331da177e4SLinus Torvalds if (err) 9341da177e4SLinus Torvalds goto return_err; 9354ac91378SJan Blunck inode = nd->path.dentry->d_inode; 93609dd17d3SMiklos Szeredi } else 93709dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9381da177e4SLinus Torvalds err = -ENOENT; 9391da177e4SLinus Torvalds if (!inode) 9401da177e4SLinus Torvalds break; 9411da177e4SLinus Torvalds if (lookup_flags & LOOKUP_DIRECTORY) { 9421da177e4SLinus Torvalds err = -ENOTDIR; 943acfa4380SAl Viro if (!inode->i_op->lookup) 9441da177e4SLinus Torvalds break; 9451da177e4SLinus Torvalds } 9461da177e4SLinus Torvalds goto return_base; 9471da177e4SLinus Torvalds lookup_parent: 9481da177e4SLinus Torvalds nd->last = this; 9491da177e4SLinus Torvalds nd->last_type = LAST_NORM; 9501da177e4SLinus Torvalds if (this.name[0] != '.') 9511da177e4SLinus Torvalds goto return_base; 9521da177e4SLinus Torvalds if (this.len == 1) 9531da177e4SLinus Torvalds nd->last_type = LAST_DOT; 9541da177e4SLinus Torvalds else if (this.len == 2 && this.name[1] == '.') 9551da177e4SLinus Torvalds nd->last_type = LAST_DOTDOT; 9561da177e4SLinus Torvalds else 9571da177e4SLinus Torvalds goto return_base; 9581da177e4SLinus Torvalds return_reval: 9591da177e4SLinus Torvalds /* 9601da177e4SLinus Torvalds * We bypassed the ordinary revalidation routines. 9611da177e4SLinus Torvalds * We may need to check the cached dentry for staleness. 9621da177e4SLinus Torvalds */ 9634ac91378SJan Blunck if (nd->path.dentry && nd->path.dentry->d_sb && 9644ac91378SJan Blunck (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { 9651da177e4SLinus Torvalds err = -ESTALE; 9661da177e4SLinus Torvalds /* Note: we do not d_invalidate() */ 9674ac91378SJan Blunck if (!nd->path.dentry->d_op->d_revalidate( 9684ac91378SJan Blunck nd->path.dentry, nd)) 9691da177e4SLinus Torvalds break; 9701da177e4SLinus Torvalds } 9711da177e4SLinus Torvalds return_base: 9721da177e4SLinus Torvalds return 0; 9731da177e4SLinus Torvalds out_dput: 9741d957f9bSJan Blunck path_put_conditional(&next, nd); 9751da177e4SLinus Torvalds break; 9761da177e4SLinus Torvalds } 9771d957f9bSJan Blunck path_put(&nd->path); 9781da177e4SLinus Torvalds return_err: 9791da177e4SLinus Torvalds return err; 9801da177e4SLinus Torvalds } 9811da177e4SLinus Torvalds 982fc9b52cdSHarvey Harrison static int path_walk(const char *name, struct nameidata *nd) 9831da177e4SLinus Torvalds { 9846de88d72SAl Viro struct path save = nd->path; 9856de88d72SAl Viro int result; 9866de88d72SAl Viro 9871da177e4SLinus Torvalds current->total_link_count = 0; 9886de88d72SAl Viro 9896de88d72SAl Viro /* make sure the stuff we saved doesn't go away */ 9906de88d72SAl Viro path_get(&save); 9916de88d72SAl Viro 9926de88d72SAl Viro result = link_path_walk(name, nd); 9936de88d72SAl Viro if (result == -ESTALE) { 9946de88d72SAl Viro /* nd->path had been dropped */ 9956de88d72SAl Viro current->total_link_count = 0; 9966de88d72SAl Viro nd->path = save; 9976de88d72SAl Viro path_get(&nd->path); 9986de88d72SAl Viro nd->flags |= LOOKUP_REVAL; 9996de88d72SAl Viro result = link_path_walk(name, nd); 10006de88d72SAl Viro } 10016de88d72SAl Viro 10026de88d72SAl Viro path_put(&save); 10036de88d72SAl Viro 10046de88d72SAl Viro return result; 10051da177e4SLinus Torvalds } 10061da177e4SLinus Torvalds 10079b4a9b14SAl Viro static int path_init(int dfd, const char *name, unsigned int flags, struct nameidata *nd) 10081da177e4SLinus Torvalds { 1009ea3834d9SPrasanna Meda int retval = 0; 1010170aa3d0SUlrich Drepper int fput_needed; 1011170aa3d0SUlrich Drepper struct file *file; 10121da177e4SLinus Torvalds 10131da177e4SLinus Torvalds nd->last_type = LAST_ROOT; /* if there are only slashes... */ 10141da177e4SLinus Torvalds nd->flags = flags; 10151da177e4SLinus Torvalds nd->depth = 0; 10162a737871SAl Viro nd->root.mnt = NULL; 10171da177e4SLinus Torvalds 10181da177e4SLinus Torvalds if (*name=='/') { 10192a737871SAl Viro set_root(nd); 10202a737871SAl Viro nd->path = nd->root; 10212a737871SAl Viro path_get(&nd->root); 10225590ff0dSUlrich Drepper } else if (dfd == AT_FDCWD) { 10232a737871SAl Viro struct fs_struct *fs = current->fs; 1024e518ddb7SAndreas Mohr read_lock(&fs->lock); 10256ac08c39SJan Blunck nd->path = fs->pwd; 10266ac08c39SJan Blunck path_get(&fs->pwd); 1027e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10285590ff0dSUlrich Drepper } else { 10295590ff0dSUlrich Drepper struct dentry *dentry; 10305590ff0dSUlrich Drepper 10315590ff0dSUlrich Drepper file = fget_light(dfd, &fput_needed); 10325590ff0dSUlrich Drepper retval = -EBADF; 1033170aa3d0SUlrich Drepper if (!file) 10346d09bb62STrond Myklebust goto out_fail; 10355590ff0dSUlrich Drepper 10360f7fc9e4SJosef "Jeff" Sipek dentry = file->f_path.dentry; 10375590ff0dSUlrich Drepper 10385590ff0dSUlrich Drepper retval = -ENOTDIR; 1039170aa3d0SUlrich Drepper if (!S_ISDIR(dentry->d_inode->i_mode)) 10406d09bb62STrond Myklebust goto fput_fail; 10415590ff0dSUlrich Drepper 10425590ff0dSUlrich Drepper retval = file_permission(file, MAY_EXEC); 1043170aa3d0SUlrich Drepper if (retval) 10446d09bb62STrond Myklebust goto fput_fail; 10455590ff0dSUlrich Drepper 10465dd784d0SJan Blunck nd->path = file->f_path; 10475dd784d0SJan Blunck path_get(&file->f_path); 10485590ff0dSUlrich Drepper 10495590ff0dSUlrich Drepper fput_light(file, fput_needed); 10501da177e4SLinus Torvalds } 10519b4a9b14SAl Viro return 0; 10522dfdd266SJosef 'Jeff' Sipek 10539b4a9b14SAl Viro fput_fail: 10549b4a9b14SAl Viro fput_light(file, fput_needed); 10559b4a9b14SAl Viro out_fail: 10569b4a9b14SAl Viro return retval; 10579b4a9b14SAl Viro } 10589b4a9b14SAl Viro 10599b4a9b14SAl Viro /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ 10609b4a9b14SAl Viro static int do_path_lookup(int dfd, const char *name, 10619b4a9b14SAl Viro unsigned int flags, struct nameidata *nd) 10629b4a9b14SAl Viro { 10639b4a9b14SAl Viro int retval = path_init(dfd, name, flags, nd); 10649b4a9b14SAl Viro if (!retval) 10652dfdd266SJosef 'Jeff' Sipek retval = path_walk(name, nd); 10664ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 10674ac91378SJan Blunck nd->path.dentry->d_inode)) 10684ac91378SJan Blunck audit_inode(name, nd->path.dentry); 10692a737871SAl Viro if (nd->root.mnt) { 10702a737871SAl Viro path_put(&nd->root); 10712a737871SAl Viro nd->root.mnt = NULL; 10722a737871SAl Viro } 1073170aa3d0SUlrich Drepper return retval; 10741da177e4SLinus Torvalds } 10751da177e4SLinus Torvalds 1076fc9b52cdSHarvey Harrison int path_lookup(const char *name, unsigned int flags, 10775590ff0dSUlrich Drepper struct nameidata *nd) 10785590ff0dSUlrich Drepper { 10795590ff0dSUlrich Drepper return do_path_lookup(AT_FDCWD, name, flags, nd); 10805590ff0dSUlrich Drepper } 10815590ff0dSUlrich Drepper 1082d1811465SAl Viro int kern_path(const char *name, unsigned int flags, struct path *path) 1083d1811465SAl Viro { 1084d1811465SAl Viro struct nameidata nd; 1085d1811465SAl Viro int res = do_path_lookup(AT_FDCWD, name, flags, &nd); 1086d1811465SAl Viro if (!res) 1087d1811465SAl Viro *path = nd.path; 1088d1811465SAl Viro return res; 1089d1811465SAl Viro } 1090d1811465SAl Viro 109116f18200SJosef 'Jeff' Sipek /** 109216f18200SJosef 'Jeff' Sipek * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair 109316f18200SJosef 'Jeff' Sipek * @dentry: pointer to dentry of the base directory 109416f18200SJosef 'Jeff' Sipek * @mnt: pointer to vfs mount of the base directory 109516f18200SJosef 'Jeff' Sipek * @name: pointer to file name 109616f18200SJosef 'Jeff' Sipek * @flags: lookup flags 109716f18200SJosef 'Jeff' Sipek * @nd: pointer to nameidata 109816f18200SJosef 'Jeff' Sipek */ 109916f18200SJosef 'Jeff' Sipek int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, 110016f18200SJosef 'Jeff' Sipek const char *name, unsigned int flags, 110116f18200SJosef 'Jeff' Sipek struct nameidata *nd) 110216f18200SJosef 'Jeff' Sipek { 110316f18200SJosef 'Jeff' Sipek int retval; 110416f18200SJosef 'Jeff' Sipek 110516f18200SJosef 'Jeff' Sipek /* same as do_path_lookup */ 110616f18200SJosef 'Jeff' Sipek nd->last_type = LAST_ROOT; 110716f18200SJosef 'Jeff' Sipek nd->flags = flags; 110816f18200SJosef 'Jeff' Sipek nd->depth = 0; 110916f18200SJosef 'Jeff' Sipek 1110c8e7f449SJan Blunck nd->path.dentry = dentry; 1111c8e7f449SJan Blunck nd->path.mnt = mnt; 1112c8e7f449SJan Blunck path_get(&nd->path); 11135b857119SAl Viro nd->root = nd->path; 11145b857119SAl Viro path_get(&nd->root); 111516f18200SJosef 'Jeff' Sipek 111616f18200SJosef 'Jeff' Sipek retval = path_walk(name, nd); 11174ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 11184ac91378SJan Blunck nd->path.dentry->d_inode)) 11194ac91378SJan Blunck audit_inode(name, nd->path.dentry); 112016f18200SJosef 'Jeff' Sipek 11212a737871SAl Viro path_put(&nd->root); 11222a737871SAl Viro nd->root.mnt = NULL; 112316f18200SJosef 'Jeff' Sipek 11242a737871SAl Viro return retval; 112516f18200SJosef 'Jeff' Sipek } 112616f18200SJosef 'Jeff' Sipek 1127834f2a4aSTrond Myklebust /** 1128834f2a4aSTrond Myklebust * path_lookup_open - lookup a file path with open intent 11297045f37bSMartin Waitz * @dfd: the directory to use as base, or AT_FDCWD 1130834f2a4aSTrond Myklebust * @name: pointer to file name 1131834f2a4aSTrond Myklebust * @lookup_flags: lookup intent flags 1132834f2a4aSTrond Myklebust * @nd: pointer to nameidata 1133834f2a4aSTrond Myklebust * @open_flags: open intent flags 1134834f2a4aSTrond Myklebust */ 11356e8341a1SAl Viro static int path_lookup_open(int dfd, const char *name, 11366e8341a1SAl Viro unsigned int lookup_flags, struct nameidata *nd, int open_flags) 1137834f2a4aSTrond Myklebust { 11388737f3a1SAl Viro struct file *filp = get_empty_filp(); 11398737f3a1SAl Viro int err; 1140834f2a4aSTrond Myklebust 11418737f3a1SAl Viro if (filp == NULL) 11428737f3a1SAl Viro return -ENFILE; 11438737f3a1SAl Viro nd->intent.open.file = filp; 11448737f3a1SAl Viro nd->intent.open.flags = open_flags; 11458737f3a1SAl Viro nd->intent.open.create_mode = 0; 11468737f3a1SAl Viro err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); 11478737f3a1SAl Viro if (IS_ERR(nd->intent.open.file)) { 11488737f3a1SAl Viro if (err == 0) { 11498737f3a1SAl Viro err = PTR_ERR(nd->intent.open.file); 11508737f3a1SAl Viro path_put(&nd->path); 11518737f3a1SAl Viro } 11528737f3a1SAl Viro } else if (err != 0) 11538737f3a1SAl Viro release_open_intent(nd); 11548737f3a1SAl Viro return err; 1155834f2a4aSTrond Myklebust } 1156834f2a4aSTrond Myklebust 1157eead1911SChristoph Hellwig static struct dentry *__lookup_hash(struct qstr *name, 1158eead1911SChristoph Hellwig struct dentry *base, struct nameidata *nd) 11591da177e4SLinus Torvalds { 11601da177e4SLinus Torvalds struct dentry *dentry; 11611da177e4SLinus Torvalds struct inode *inode; 11621da177e4SLinus Torvalds int err; 11631da177e4SLinus Torvalds 11641da177e4SLinus Torvalds inode = base->d_inode; 11651da177e4SLinus Torvalds 11661da177e4SLinus Torvalds /* 11671da177e4SLinus Torvalds * See if the low-level filesystem might want 11681da177e4SLinus Torvalds * to use its own hash.. 11691da177e4SLinus Torvalds */ 11701da177e4SLinus Torvalds if (base->d_op && base->d_op->d_hash) { 11711da177e4SLinus Torvalds err = base->d_op->d_hash(base, name); 11721da177e4SLinus Torvalds dentry = ERR_PTR(err); 11731da177e4SLinus Torvalds if (err < 0) 11741da177e4SLinus Torvalds goto out; 11751da177e4SLinus Torvalds } 11761da177e4SLinus Torvalds 11771da177e4SLinus Torvalds dentry = cached_lookup(base, name, nd); 11781da177e4SLinus Torvalds if (!dentry) { 1179d70b67c8SMiklos Szeredi struct dentry *new; 1180d70b67c8SMiklos Szeredi 1181d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 1182d70b67c8SMiklos Szeredi dentry = ERR_PTR(-ENOENT); 1183d70b67c8SMiklos Szeredi if (IS_DEADDIR(inode)) 1184d70b67c8SMiklos Szeredi goto out; 1185d70b67c8SMiklos Szeredi 1186d70b67c8SMiklos Szeredi new = d_alloc(base, name); 11871da177e4SLinus Torvalds dentry = ERR_PTR(-ENOMEM); 11881da177e4SLinus Torvalds if (!new) 11891da177e4SLinus Torvalds goto out; 11901da177e4SLinus Torvalds dentry = inode->i_op->lookup(inode, new, nd); 11911da177e4SLinus Torvalds if (!dentry) 11921da177e4SLinus Torvalds dentry = new; 11931da177e4SLinus Torvalds else 11941da177e4SLinus Torvalds dput(new); 11951da177e4SLinus Torvalds } 11961da177e4SLinus Torvalds out: 11971da177e4SLinus Torvalds return dentry; 11981da177e4SLinus Torvalds } 11991da177e4SLinus Torvalds 1200057f6c01SJames Morris /* 1201057f6c01SJames Morris * Restricted form of lookup. Doesn't follow links, single-component only, 1202057f6c01SJames Morris * needs parent already locked. Doesn't follow mounts. 1203057f6c01SJames Morris * SMP-safe. 1204057f6c01SJames Morris */ 1205a244e169SAdrian Bunk static struct dentry *lookup_hash(struct nameidata *nd) 12061da177e4SLinus Torvalds { 1207eead1911SChristoph Hellwig int err; 1208eead1911SChristoph Hellwig 1209f419a2e3SAl Viro err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); 1210eead1911SChristoph Hellwig if (err) 1211eead1911SChristoph Hellwig return ERR_PTR(err); 12124ac91378SJan Blunck return __lookup_hash(&nd->last, nd->path.dentry, nd); 12131da177e4SLinus Torvalds } 12141da177e4SLinus Torvalds 1215eead1911SChristoph Hellwig static int __lookup_one_len(const char *name, struct qstr *this, 1216eead1911SChristoph Hellwig struct dentry *base, int len) 12171da177e4SLinus Torvalds { 12181da177e4SLinus Torvalds unsigned long hash; 12191da177e4SLinus Torvalds unsigned int c; 12201da177e4SLinus Torvalds 1221057f6c01SJames Morris this->name = name; 1222057f6c01SJames Morris this->len = len; 12231da177e4SLinus Torvalds if (!len) 1224057f6c01SJames Morris return -EACCES; 12251da177e4SLinus Torvalds 12261da177e4SLinus Torvalds hash = init_name_hash(); 12271da177e4SLinus Torvalds while (len--) { 12281da177e4SLinus Torvalds c = *(const unsigned char *)name++; 12291da177e4SLinus Torvalds if (c == '/' || c == '\0') 1230057f6c01SJames Morris return -EACCES; 12311da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 12321da177e4SLinus Torvalds } 1233057f6c01SJames Morris this->hash = end_name_hash(hash); 1234057f6c01SJames Morris return 0; 1235057f6c01SJames Morris } 12361da177e4SLinus Torvalds 1237eead1911SChristoph Hellwig /** 1238a6b91919SRandy Dunlap * lookup_one_len - filesystem helper to lookup single pathname component 1239eead1911SChristoph Hellwig * @name: pathname component to lookup 1240eead1911SChristoph Hellwig * @base: base directory to lookup from 1241eead1911SChristoph Hellwig * @len: maximum length @len should be interpreted to 1242eead1911SChristoph Hellwig * 1243a6b91919SRandy Dunlap * Note that this routine is purely a helper for filesystem usage and should 1244a6b91919SRandy Dunlap * not be called by generic code. Also note that by using this function the 1245eead1911SChristoph Hellwig * nameidata argument is passed to the filesystem methods and a filesystem 1246eead1911SChristoph Hellwig * using this helper needs to be prepared for that. 1247eead1911SChristoph Hellwig */ 1248057f6c01SJames Morris struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) 1249057f6c01SJames Morris { 1250057f6c01SJames Morris int err; 1251057f6c01SJames Morris struct qstr this; 1252057f6c01SJames Morris 12532f9092e1SDavid Woodhouse WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); 12542f9092e1SDavid Woodhouse 1255057f6c01SJames Morris err = __lookup_one_len(name, &this, base, len); 1256057f6c01SJames Morris if (err) 1257057f6c01SJames Morris return ERR_PTR(err); 1258eead1911SChristoph Hellwig 1259f419a2e3SAl Viro err = inode_permission(base->d_inode, MAY_EXEC); 1260eead1911SChristoph Hellwig if (err) 1261eead1911SChristoph Hellwig return ERR_PTR(err); 126249705b77SChristoph Hellwig return __lookup_hash(&this, base, NULL); 1263057f6c01SJames Morris } 1264057f6c01SJames Morris 12652d8f3038SAl Viro int user_path_at(int dfd, const char __user *name, unsigned flags, 12662d8f3038SAl Viro struct path *path) 12671da177e4SLinus Torvalds { 12682d8f3038SAl Viro struct nameidata nd; 12691da177e4SLinus Torvalds char *tmp = getname(name); 12701da177e4SLinus Torvalds int err = PTR_ERR(tmp); 12711da177e4SLinus Torvalds if (!IS_ERR(tmp)) { 12722d8f3038SAl Viro 12732d8f3038SAl Viro BUG_ON(flags & LOOKUP_PARENT); 12742d8f3038SAl Viro 12752d8f3038SAl Viro err = do_path_lookup(dfd, tmp, flags, &nd); 12761da177e4SLinus Torvalds putname(tmp); 12772d8f3038SAl Viro if (!err) 12782d8f3038SAl Viro *path = nd.path; 12791da177e4SLinus Torvalds } 12801da177e4SLinus Torvalds return err; 12811da177e4SLinus Torvalds } 12821da177e4SLinus Torvalds 12832ad94ae6SAl Viro static int user_path_parent(int dfd, const char __user *path, 12842ad94ae6SAl Viro struct nameidata *nd, char **name) 12852ad94ae6SAl Viro { 12862ad94ae6SAl Viro char *s = getname(path); 12872ad94ae6SAl Viro int error; 12882ad94ae6SAl Viro 12892ad94ae6SAl Viro if (IS_ERR(s)) 12902ad94ae6SAl Viro return PTR_ERR(s); 12912ad94ae6SAl Viro 12922ad94ae6SAl Viro error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); 12932ad94ae6SAl Viro if (error) 12942ad94ae6SAl Viro putname(s); 12952ad94ae6SAl Viro else 12962ad94ae6SAl Viro *name = s; 12972ad94ae6SAl Viro 12982ad94ae6SAl Viro return error; 12992ad94ae6SAl Viro } 13002ad94ae6SAl Viro 13011da177e4SLinus Torvalds /* 13021da177e4SLinus Torvalds * It's inline, so penalty for filesystems that don't use sticky bit is 13031da177e4SLinus Torvalds * minimal. 13041da177e4SLinus Torvalds */ 13051da177e4SLinus Torvalds static inline int check_sticky(struct inode *dir, struct inode *inode) 13061da177e4SLinus Torvalds { 1307da9592edSDavid Howells uid_t fsuid = current_fsuid(); 1308da9592edSDavid Howells 13091da177e4SLinus Torvalds if (!(dir->i_mode & S_ISVTX)) 13101da177e4SLinus Torvalds return 0; 1311da9592edSDavid Howells if (inode->i_uid == fsuid) 13121da177e4SLinus Torvalds return 0; 1313da9592edSDavid Howells if (dir->i_uid == fsuid) 13141da177e4SLinus Torvalds return 0; 13151da177e4SLinus Torvalds return !capable(CAP_FOWNER); 13161da177e4SLinus Torvalds } 13171da177e4SLinus Torvalds 13181da177e4SLinus Torvalds /* 13191da177e4SLinus Torvalds * Check whether we can remove a link victim from directory dir, check 13201da177e4SLinus Torvalds * whether the type of victim is right. 13211da177e4SLinus Torvalds * 1. We can't do it if dir is read-only (done in permission()) 13221da177e4SLinus Torvalds * 2. We should have write and exec permissions on dir 13231da177e4SLinus Torvalds * 3. We can't remove anything from append-only dir 13241da177e4SLinus Torvalds * 4. We can't do anything with immutable dir (done in permission()) 13251da177e4SLinus Torvalds * 5. If the sticky bit on dir is set we should either 13261da177e4SLinus Torvalds * a. be owner of dir, or 13271da177e4SLinus Torvalds * b. be owner of victim, or 13281da177e4SLinus Torvalds * c. have CAP_FOWNER capability 13291da177e4SLinus Torvalds * 6. If the victim is append-only or immutable we can't do antyhing with 13301da177e4SLinus Torvalds * links pointing to it. 13311da177e4SLinus Torvalds * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. 13321da177e4SLinus Torvalds * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. 13331da177e4SLinus Torvalds * 9. We can't remove a root or mountpoint. 13341da177e4SLinus Torvalds * 10. We don't allow removal of NFS sillyrenamed files; it's handled by 13351da177e4SLinus Torvalds * nfs_async_unlink(). 13361da177e4SLinus Torvalds */ 1337858119e1SArjan van de Ven static int may_delete(struct inode *dir,struct dentry *victim,int isdir) 13381da177e4SLinus Torvalds { 13391da177e4SLinus Torvalds int error; 13401da177e4SLinus Torvalds 13411da177e4SLinus Torvalds if (!victim->d_inode) 13421da177e4SLinus Torvalds return -ENOENT; 13431da177e4SLinus Torvalds 13441da177e4SLinus Torvalds BUG_ON(victim->d_parent->d_inode != dir); 13455a190ae6SAl Viro audit_inode_child(victim->d_name.name, victim, dir); 13461da177e4SLinus Torvalds 1347f419a2e3SAl Viro error = inode_permission(dir, MAY_WRITE | MAY_EXEC); 13481da177e4SLinus Torvalds if (error) 13491da177e4SLinus Torvalds return error; 13501da177e4SLinus Torvalds if (IS_APPEND(dir)) 13511da177e4SLinus Torvalds return -EPERM; 13521da177e4SLinus Torvalds if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| 1353f9454548SHugh Dickins IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) 13541da177e4SLinus Torvalds return -EPERM; 13551da177e4SLinus Torvalds if (isdir) { 13561da177e4SLinus Torvalds if (!S_ISDIR(victim->d_inode->i_mode)) 13571da177e4SLinus Torvalds return -ENOTDIR; 13581da177e4SLinus Torvalds if (IS_ROOT(victim)) 13591da177e4SLinus Torvalds return -EBUSY; 13601da177e4SLinus Torvalds } else if (S_ISDIR(victim->d_inode->i_mode)) 13611da177e4SLinus Torvalds return -EISDIR; 13621da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 13631da177e4SLinus Torvalds return -ENOENT; 13641da177e4SLinus Torvalds if (victim->d_flags & DCACHE_NFSFS_RENAMED) 13651da177e4SLinus Torvalds return -EBUSY; 13661da177e4SLinus Torvalds return 0; 13671da177e4SLinus Torvalds } 13681da177e4SLinus Torvalds 13691da177e4SLinus Torvalds /* Check whether we can create an object with dentry child in directory 13701da177e4SLinus Torvalds * dir. 13711da177e4SLinus Torvalds * 1. We can't do it if child already exists (open has special treatment for 13721da177e4SLinus Torvalds * this case, but since we are inlined it's OK) 13731da177e4SLinus Torvalds * 2. We can't do it if dir is read-only (done in permission()) 13741da177e4SLinus Torvalds * 3. We should have write and exec permissions on dir 13751da177e4SLinus Torvalds * 4. We can't do it if dir is immutable (done in permission()) 13761da177e4SLinus Torvalds */ 1377a95164d9SMiklos Szeredi static inline int may_create(struct inode *dir, struct dentry *child) 13781da177e4SLinus Torvalds { 13791da177e4SLinus Torvalds if (child->d_inode) 13801da177e4SLinus Torvalds return -EEXIST; 13811da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 13821da177e4SLinus Torvalds return -ENOENT; 1383f419a2e3SAl Viro return inode_permission(dir, MAY_WRITE | MAY_EXEC); 13841da177e4SLinus Torvalds } 13851da177e4SLinus Torvalds 13861da177e4SLinus Torvalds /* 13871da177e4SLinus Torvalds * O_DIRECTORY translates into forcing a directory lookup. 13881da177e4SLinus Torvalds */ 13891da177e4SLinus Torvalds static inline int lookup_flags(unsigned int f) 13901da177e4SLinus Torvalds { 13911da177e4SLinus Torvalds unsigned long retval = LOOKUP_FOLLOW; 13921da177e4SLinus Torvalds 13931da177e4SLinus Torvalds if (f & O_NOFOLLOW) 13941da177e4SLinus Torvalds retval &= ~LOOKUP_FOLLOW; 13951da177e4SLinus Torvalds 13961da177e4SLinus Torvalds if (f & O_DIRECTORY) 13971da177e4SLinus Torvalds retval |= LOOKUP_DIRECTORY; 13981da177e4SLinus Torvalds 13991da177e4SLinus Torvalds return retval; 14001da177e4SLinus Torvalds } 14011da177e4SLinus Torvalds 14021da177e4SLinus Torvalds /* 14031da177e4SLinus Torvalds * p1 and p2 should be directories on the same fs. 14041da177e4SLinus Torvalds */ 14051da177e4SLinus Torvalds struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) 14061da177e4SLinus Torvalds { 14071da177e4SLinus Torvalds struct dentry *p; 14081da177e4SLinus Torvalds 14091da177e4SLinus Torvalds if (p1 == p2) { 1410f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 14111da177e4SLinus Torvalds return NULL; 14121da177e4SLinus Torvalds } 14131da177e4SLinus Torvalds 1414a11f3a05SArjan van de Ven mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14151da177e4SLinus Torvalds 1416e2761a11SOGAWA Hirofumi p = d_ancestor(p2, p1); 1417e2761a11SOGAWA Hirofumi if (p) { 1418f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); 1419f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); 14201da177e4SLinus Torvalds return p; 14211da177e4SLinus Torvalds } 14221da177e4SLinus Torvalds 1423e2761a11SOGAWA Hirofumi p = d_ancestor(p1, p2); 1424e2761a11SOGAWA Hirofumi if (p) { 1425f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1426f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14271da177e4SLinus Torvalds return p; 14281da177e4SLinus Torvalds } 14291da177e4SLinus Torvalds 1430f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1431f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14321da177e4SLinus Torvalds return NULL; 14331da177e4SLinus Torvalds } 14341da177e4SLinus Torvalds 14351da177e4SLinus Torvalds void unlock_rename(struct dentry *p1, struct dentry *p2) 14361da177e4SLinus Torvalds { 14371b1dcc1bSJes Sorensen mutex_unlock(&p1->d_inode->i_mutex); 14381da177e4SLinus Torvalds if (p1 != p2) { 14391b1dcc1bSJes Sorensen mutex_unlock(&p2->d_inode->i_mutex); 1440a11f3a05SArjan van de Ven mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14411da177e4SLinus Torvalds } 14421da177e4SLinus Torvalds } 14431da177e4SLinus Torvalds 14441da177e4SLinus Torvalds int vfs_create(struct inode *dir, struct dentry *dentry, int mode, 14451da177e4SLinus Torvalds struct nameidata *nd) 14461da177e4SLinus Torvalds { 1447a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 14481da177e4SLinus Torvalds 14491da177e4SLinus Torvalds if (error) 14501da177e4SLinus Torvalds return error; 14511da177e4SLinus Torvalds 1452acfa4380SAl Viro if (!dir->i_op->create) 14531da177e4SLinus Torvalds return -EACCES; /* shouldn't it be ENOSYS? */ 14541da177e4SLinus Torvalds mode &= S_IALLUGO; 14551da177e4SLinus Torvalds mode |= S_IFREG; 14561da177e4SLinus Torvalds error = security_inode_create(dir, dentry, mode); 14571da177e4SLinus Torvalds if (error) 14581da177e4SLinus Torvalds return error; 14599e3509e2SJan Kara vfs_dq_init(dir); 14601da177e4SLinus Torvalds error = dir->i_op->create(dir, dentry, mode, nd); 1461a74574aaSStephen Smalley if (!error) 1462f38aa942SAmy Griffis fsnotify_create(dir, dentry); 14631da177e4SLinus Torvalds return error; 14641da177e4SLinus Torvalds } 14651da177e4SLinus Torvalds 14663fb64190SChristoph Hellwig int may_open(struct path *path, int acc_mode, int flag) 14671da177e4SLinus Torvalds { 14683fb64190SChristoph Hellwig struct dentry *dentry = path->dentry; 14691da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 14701da177e4SLinus Torvalds int error; 14711da177e4SLinus Torvalds 14721da177e4SLinus Torvalds if (!inode) 14731da177e4SLinus Torvalds return -ENOENT; 14741da177e4SLinus Torvalds 1475c8fe8f30SChristoph Hellwig switch (inode->i_mode & S_IFMT) { 1476c8fe8f30SChristoph Hellwig case S_IFLNK: 14771da177e4SLinus Torvalds return -ELOOP; 1478c8fe8f30SChristoph Hellwig case S_IFDIR: 1479c8fe8f30SChristoph Hellwig if (acc_mode & MAY_WRITE) 14801da177e4SLinus Torvalds return -EISDIR; 1481c8fe8f30SChristoph Hellwig break; 1482c8fe8f30SChristoph Hellwig case S_IFBLK: 1483c8fe8f30SChristoph Hellwig case S_IFCHR: 14843fb64190SChristoph Hellwig if (path->mnt->mnt_flags & MNT_NODEV) 14851da177e4SLinus Torvalds return -EACCES; 1486c8fe8f30SChristoph Hellwig /*FALLTHRU*/ 1487c8fe8f30SChristoph Hellwig case S_IFIFO: 1488c8fe8f30SChristoph Hellwig case S_IFSOCK: 14891da177e4SLinus Torvalds flag &= ~O_TRUNC; 1490c8fe8f30SChristoph Hellwig break; 14914a3fd211SDave Hansen } 1492b41572e9SDave Hansen 14933fb64190SChristoph Hellwig error = inode_permission(inode, acc_mode); 1494b41572e9SDave Hansen if (error) 1495b41572e9SDave Hansen return error; 14966146f0d5SMimi Zohar 14976c1488fdSMimi Zohar error = ima_path_check(path, acc_mode ? 14986c1488fdSMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) : 14996c1488fdSMimi Zohar ACC_MODE(flag) & (MAY_READ | MAY_WRITE), 1500b9fc745dSMimi Zohar IMA_COUNT_UPDATE); 15016c1488fdSMimi Zohar 15026146f0d5SMimi Zohar if (error) 15036146f0d5SMimi Zohar return error; 15041da177e4SLinus Torvalds /* 15051da177e4SLinus Torvalds * An append-only file must be opened in append mode for writing. 15061da177e4SLinus Torvalds */ 15071da177e4SLinus Torvalds if (IS_APPEND(inode)) { 1508acd0c935SMimi Zohar error = -EPERM; 15091da177e4SLinus Torvalds if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) 1510acd0c935SMimi Zohar goto err_out; 15111da177e4SLinus Torvalds if (flag & O_TRUNC) 1512acd0c935SMimi Zohar goto err_out; 15131da177e4SLinus Torvalds } 15141da177e4SLinus Torvalds 15151da177e4SLinus Torvalds /* O_NOATIME can only be set by the owner or superuser */ 15161da177e4SLinus Torvalds if (flag & O_NOATIME) 1517acd0c935SMimi Zohar if (!is_owner_or_cap(inode)) { 1518acd0c935SMimi Zohar error = -EPERM; 1519acd0c935SMimi Zohar goto err_out; 1520acd0c935SMimi Zohar } 15211da177e4SLinus Torvalds 15221da177e4SLinus Torvalds /* 15231da177e4SLinus Torvalds * Ensure there are no outstanding leases on the file. 15241da177e4SLinus Torvalds */ 15251da177e4SLinus Torvalds error = break_lease(inode, flag); 15261da177e4SLinus Torvalds if (error) 1527acd0c935SMimi Zohar goto err_out; 15281da177e4SLinus Torvalds 15291da177e4SLinus Torvalds if (flag & O_TRUNC) { 15301da177e4SLinus Torvalds error = get_write_access(inode); 15311da177e4SLinus Torvalds if (error) 1532acd0c935SMimi Zohar goto err_out; 15331da177e4SLinus Torvalds 15341da177e4SLinus Torvalds /* 15351da177e4SLinus Torvalds * Refuse to truncate files with mandatory locks held on them. 15361da177e4SLinus Torvalds */ 15371da177e4SLinus Torvalds error = locks_verify_locked(inode); 1538be6d3e56SKentaro Takeda if (!error) 15393fb64190SChristoph Hellwig error = security_path_truncate(path, 0, 1540be6d3e56SKentaro Takeda ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); 15411da177e4SLinus Torvalds if (!error) { 15429e3509e2SJan Kara vfs_dq_init(inode); 15431da177e4SLinus Torvalds 1544d139d7ffSMiklos Szeredi error = do_truncate(dentry, 0, 1545d139d7ffSMiklos Szeredi ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, 1546d139d7ffSMiklos Szeredi NULL); 15471da177e4SLinus Torvalds } 15481da177e4SLinus Torvalds put_write_access(inode); 15491da177e4SLinus Torvalds if (error) 1550acd0c935SMimi Zohar goto err_out; 15511da177e4SLinus Torvalds } else 15521da177e4SLinus Torvalds if (flag & FMODE_WRITE) 15539e3509e2SJan Kara vfs_dq_init(inode); 15541da177e4SLinus Torvalds 15551da177e4SLinus Torvalds return 0; 1556acd0c935SMimi Zohar err_out: 1557acd0c935SMimi Zohar ima_counts_put(path, acc_mode ? 1558acd0c935SMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC) : 1559acd0c935SMimi Zohar ACC_MODE(flag) & (MAY_READ | MAY_WRITE)); 1560acd0c935SMimi Zohar return error; 15611da177e4SLinus Torvalds } 15621da177e4SLinus Torvalds 1563d57999e1SDave Hansen /* 1564d57999e1SDave Hansen * Be careful about ever adding any more callers of this 1565d57999e1SDave Hansen * function. Its flags must be in the namei format, not 1566d57999e1SDave Hansen * what get passed to sys_open(). 1567d57999e1SDave Hansen */ 1568d57999e1SDave Hansen static int __open_namei_create(struct nameidata *nd, struct path *path, 1569aab520e2SDave Hansen int flag, int mode) 1570aab520e2SDave Hansen { 1571aab520e2SDave Hansen int error; 15724ac91378SJan Blunck struct dentry *dir = nd->path.dentry; 1573aab520e2SDave Hansen 1574aab520e2SDave Hansen if (!IS_POSIXACL(dir->d_inode)) 1575ce3b0f8dSAl Viro mode &= ~current_umask(); 1576be6d3e56SKentaro Takeda error = security_path_mknod(&nd->path, path->dentry, mode, 0); 1577be6d3e56SKentaro Takeda if (error) 1578be6d3e56SKentaro Takeda goto out_unlock; 1579aab520e2SDave Hansen error = vfs_create(dir->d_inode, path->dentry, mode, nd); 1580be6d3e56SKentaro Takeda out_unlock: 1581aab520e2SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 15824ac91378SJan Blunck dput(nd->path.dentry); 15834ac91378SJan Blunck nd->path.dentry = path->dentry; 1584aab520e2SDave Hansen if (error) 1585aab520e2SDave Hansen return error; 1586aab520e2SDave Hansen /* Don't check for write permission, don't truncate */ 15873fb64190SChristoph Hellwig return may_open(&nd->path, 0, flag & ~O_TRUNC); 1588aab520e2SDave Hansen } 1589aab520e2SDave Hansen 15901da177e4SLinus Torvalds /* 1591d57999e1SDave Hansen * Note that while the flag value (low two bits) for sys_open means: 1592d57999e1SDave Hansen * 00 - read-only 1593d57999e1SDave Hansen * 01 - write-only 1594d57999e1SDave Hansen * 10 - read-write 1595d57999e1SDave Hansen * 11 - special 1596d57999e1SDave Hansen * it is changed into 1597d57999e1SDave Hansen * 00 - no permissions needed 1598d57999e1SDave Hansen * 01 - read-permission 1599d57999e1SDave Hansen * 10 - write-permission 1600d57999e1SDave Hansen * 11 - read-write 1601d57999e1SDave Hansen * for the internal routines (ie open_namei()/follow_link() etc) 1602d57999e1SDave Hansen * This is more logical, and also allows the 00 "no perm needed" 1603d57999e1SDave Hansen * to be used for symlinks (where the permissions are checked 1604d57999e1SDave Hansen * later). 1605d57999e1SDave Hansen * 1606d57999e1SDave Hansen */ 1607d57999e1SDave Hansen static inline int open_to_namei_flags(int flag) 1608d57999e1SDave Hansen { 1609d57999e1SDave Hansen if ((flag+1) & O_ACCMODE) 1610d57999e1SDave Hansen flag++; 1611d57999e1SDave Hansen return flag; 1612d57999e1SDave Hansen } 1613d57999e1SDave Hansen 16144a3fd211SDave Hansen static int open_will_write_to_fs(int flag, struct inode *inode) 16154a3fd211SDave Hansen { 1616d57999e1SDave Hansen /* 16174a3fd211SDave Hansen * We'll never write to the fs underlying 16184a3fd211SDave Hansen * a device file. 16194a3fd211SDave Hansen */ 16204a3fd211SDave Hansen if (special_file(inode->i_mode)) 16214a3fd211SDave Hansen return 0; 16224a3fd211SDave Hansen return (flag & O_TRUNC); 16234a3fd211SDave Hansen } 16244a3fd211SDave Hansen 16254a3fd211SDave Hansen /* 16264a3fd211SDave Hansen * Note that the low bits of the passed in "open_flag" 16274a3fd211SDave Hansen * are not the same as in the local variable "flag". See 16284a3fd211SDave Hansen * open_to_namei_flags() for more details. 16291da177e4SLinus Torvalds */ 1630a70e65dfSChristoph Hellwig struct file *do_filp_open(int dfd, const char *pathname, 16316e8341a1SAl Viro int open_flag, int mode, int acc_mode) 16321da177e4SLinus Torvalds { 16334a3fd211SDave Hansen struct file *filp; 1634a70e65dfSChristoph Hellwig struct nameidata nd; 16356e8341a1SAl Viro int error; 16366de88d72SAl Viro struct path path, save; 16371da177e4SLinus Torvalds struct dentry *dir; 16381da177e4SLinus Torvalds int count = 0; 16394a3fd211SDave Hansen int will_write; 1640d57999e1SDave Hansen int flag = open_to_namei_flags(open_flag); 16411da177e4SLinus Torvalds 16426b2f3d1fSChristoph Hellwig /* 16436b2f3d1fSChristoph Hellwig * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only 16446b2f3d1fSChristoph Hellwig * check for O_DSYNC if the need any syncing at all we enforce it's 16456b2f3d1fSChristoph Hellwig * always set instead of having to deal with possibly weird behaviour 16466b2f3d1fSChristoph Hellwig * for malicious applications setting only __O_SYNC. 16476b2f3d1fSChristoph Hellwig */ 16486b2f3d1fSChristoph Hellwig if (open_flag & __O_SYNC) 16496b2f3d1fSChristoph Hellwig open_flag |= O_DSYNC; 16506b2f3d1fSChristoph Hellwig 16516e8341a1SAl Viro if (!acc_mode) 1652b77b0646SAl Viro acc_mode = MAY_OPEN | ACC_MODE(flag); 16531da177e4SLinus Torvalds 1654834f2a4aSTrond Myklebust /* O_TRUNC implies we need access checks for write permissions */ 1655834f2a4aSTrond Myklebust if (flag & O_TRUNC) 1656834f2a4aSTrond Myklebust acc_mode |= MAY_WRITE; 1657834f2a4aSTrond Myklebust 16581da177e4SLinus Torvalds /* Allow the LSM permission hook to distinguish append 16591da177e4SLinus Torvalds access from general write access. */ 16601da177e4SLinus Torvalds if (flag & O_APPEND) 16611da177e4SLinus Torvalds acc_mode |= MAY_APPEND; 16621da177e4SLinus Torvalds 16631da177e4SLinus Torvalds /* 16641da177e4SLinus Torvalds * The simplest case - just a plain lookup. 16651da177e4SLinus Torvalds */ 16661da177e4SLinus Torvalds if (!(flag & O_CREAT)) { 16675590ff0dSUlrich Drepper error = path_lookup_open(dfd, pathname, lookup_flags(flag), 1668a70e65dfSChristoph Hellwig &nd, flag); 16691da177e4SLinus Torvalds if (error) 1670a70e65dfSChristoph Hellwig return ERR_PTR(error); 16711da177e4SLinus Torvalds goto ok; 16721da177e4SLinus Torvalds } 16731da177e4SLinus Torvalds 16741da177e4SLinus Torvalds /* 16751da177e4SLinus Torvalds * Create - we need to know the parent. 16761da177e4SLinus Torvalds */ 16779b4a9b14SAl Viro error = path_init(dfd, pathname, LOOKUP_PARENT, &nd); 16781da177e4SLinus Torvalds if (error) 1679a70e65dfSChristoph Hellwig return ERR_PTR(error); 16809b4a9b14SAl Viro error = path_walk(pathname, &nd); 1681654f562cSJ. R. Okajima if (error) { 1682654f562cSJ. R. Okajima if (nd.root.mnt) 1683654f562cSJ. R. Okajima path_put(&nd.root); 16849b4a9b14SAl Viro return ERR_PTR(error); 1685654f562cSJ. R. Okajima } 16869b4a9b14SAl Viro if (unlikely(!audit_dummy_context())) 16879b4a9b14SAl Viro audit_inode(pathname, nd.path.dentry); 16881da177e4SLinus Torvalds 16891da177e4SLinus Torvalds /* 16901da177e4SLinus Torvalds * We have the parent and last component. First of all, check 16911da177e4SLinus Torvalds * that we are not asked to creat(2) an obvious directory - that 16921da177e4SLinus Torvalds * will not do. 16931da177e4SLinus Torvalds */ 16941da177e4SLinus Torvalds error = -EISDIR; 1695a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) 16968737f3a1SAl Viro goto exit_parent; 16971da177e4SLinus Torvalds 16988737f3a1SAl Viro error = -ENFILE; 16998737f3a1SAl Viro filp = get_empty_filp(); 17008737f3a1SAl Viro if (filp == NULL) 17018737f3a1SAl Viro goto exit_parent; 17028737f3a1SAl Viro nd.intent.open.file = filp; 17038737f3a1SAl Viro nd.intent.open.flags = flag; 17048737f3a1SAl Viro nd.intent.open.create_mode = mode; 1705a70e65dfSChristoph Hellwig dir = nd.path.dentry; 1706a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 17078737f3a1SAl Viro nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; 17083516586aSAl Viro if (flag & O_EXCL) 17093516586aSAl Viro nd.flags |= LOOKUP_EXCL; 17101b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1711a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1712a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 17131da177e4SLinus Torvalds 17141da177e4SLinus Torvalds do_last: 17154e7506e4SAl Viro error = PTR_ERR(path.dentry); 17164e7506e4SAl Viro if (IS_ERR(path.dentry)) { 17171b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17181da177e4SLinus Torvalds goto exit; 17191da177e4SLinus Torvalds } 17201da177e4SLinus Torvalds 1721a70e65dfSChristoph Hellwig if (IS_ERR(nd.intent.open.file)) { 1722a70e65dfSChristoph Hellwig error = PTR_ERR(nd.intent.open.file); 17234a3fd211SDave Hansen goto exit_mutex_unlock; 17244af4c52fSOleg Drokin } 17254af4c52fSOleg Drokin 17261da177e4SLinus Torvalds /* Negative dentry, just create the file */ 17274e7506e4SAl Viro if (!path.dentry->d_inode) { 17284a3fd211SDave Hansen /* 17294a3fd211SDave Hansen * This write is needed to ensure that a 17304a3fd211SDave Hansen * ro->rw transition does not occur between 17314a3fd211SDave Hansen * the time when the file is created and when 17324a3fd211SDave Hansen * a permanent write count is taken through 17334a3fd211SDave Hansen * the 'struct file' in nameidata_to_filp(). 17344a3fd211SDave Hansen */ 17354a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17361da177e4SLinus Torvalds if (error) 17374a3fd211SDave Hansen goto exit_mutex_unlock; 17384a3fd211SDave Hansen error = __open_namei_create(&nd, &path, flag, mode); 17394a3fd211SDave Hansen if (error) { 17404a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17411da177e4SLinus Torvalds goto exit; 17424a3fd211SDave Hansen } 17434a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 174494e5d714SMimi Zohar if (IS_ERR(filp)) 174594e5d714SMimi Zohar ima_counts_put(&nd.path, 174694e5d714SMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | 174794e5d714SMimi Zohar MAY_EXEC)); 17484a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 1749654f562cSJ. R. Okajima if (nd.root.mnt) 1750654f562cSJ. R. Okajima path_put(&nd.root); 17514a3fd211SDave Hansen return filp; 17521da177e4SLinus Torvalds } 17531da177e4SLinus Torvalds 17541da177e4SLinus Torvalds /* 17551da177e4SLinus Torvalds * It already exists. 17561da177e4SLinus Torvalds */ 17571b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17585a190ae6SAl Viro audit_inode(pathname, path.dentry); 17591da177e4SLinus Torvalds 17601da177e4SLinus Torvalds error = -EEXIST; 17611da177e4SLinus Torvalds if (flag & O_EXCL) 17621da177e4SLinus Torvalds goto exit_dput; 17631da177e4SLinus Torvalds 1764e13b210fSAl Viro if (__follow_mount(&path)) { 17651da177e4SLinus Torvalds error = -ELOOP; 1766ba7a4c1aSAl Viro if (flag & O_NOFOLLOW) 1767ba7a4c1aSAl Viro goto exit_dput; 17681da177e4SLinus Torvalds } 17693e2efce0SAmy Griffis 17701da177e4SLinus Torvalds error = -ENOENT; 17714e7506e4SAl Viro if (!path.dentry->d_inode) 17721da177e4SLinus Torvalds goto exit_dput; 1773acfa4380SAl Viro if (path.dentry->d_inode->i_op->follow_link) 17741da177e4SLinus Torvalds goto do_link; 17751da177e4SLinus Torvalds 1776a70e65dfSChristoph Hellwig path_to_nameidata(&path, &nd); 17771da177e4SLinus Torvalds error = -EISDIR; 17784e7506e4SAl Viro if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) 17791da177e4SLinus Torvalds goto exit; 17801da177e4SLinus Torvalds ok: 17814a3fd211SDave Hansen /* 17824a3fd211SDave Hansen * Consider: 17834a3fd211SDave Hansen * 1. may_open() truncates a file 17844a3fd211SDave Hansen * 2. a rw->ro mount transition occurs 17854a3fd211SDave Hansen * 3. nameidata_to_filp() fails due to 17864a3fd211SDave Hansen * the ro mount. 17874a3fd211SDave Hansen * That would be inconsistent, and should 17884a3fd211SDave Hansen * be avoided. Taking this mnt write here 17894a3fd211SDave Hansen * ensures that (2) can not occur. 17904a3fd211SDave Hansen */ 17914a3fd211SDave Hansen will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); 17924a3fd211SDave Hansen if (will_write) { 17934a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17941da177e4SLinus Torvalds if (error) 17951da177e4SLinus Torvalds goto exit; 17964a3fd211SDave Hansen } 17973fb64190SChristoph Hellwig error = may_open(&nd.path, acc_mode, flag); 17984a3fd211SDave Hansen if (error) { 17994a3fd211SDave Hansen if (will_write) 18004a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 18014a3fd211SDave Hansen goto exit; 18024a3fd211SDave Hansen } 18034a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 180494e5d714SMimi Zohar if (IS_ERR(filp)) 180594e5d714SMimi Zohar ima_counts_put(&nd.path, 180694e5d714SMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); 18074a3fd211SDave Hansen /* 18084a3fd211SDave Hansen * It is now safe to drop the mnt write 18094a3fd211SDave Hansen * because the filp has had a write taken 18104a3fd211SDave Hansen * on its behalf. 18114a3fd211SDave Hansen */ 18124a3fd211SDave Hansen if (will_write) 18134a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 1814654f562cSJ. R. Okajima if (nd.root.mnt) 1815654f562cSJ. R. Okajima path_put(&nd.root); 18164a3fd211SDave Hansen return filp; 18171da177e4SLinus Torvalds 18184a3fd211SDave Hansen exit_mutex_unlock: 18194a3fd211SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 18201da177e4SLinus Torvalds exit_dput: 1821a70e65dfSChristoph Hellwig path_put_conditional(&path, &nd); 18221da177e4SLinus Torvalds exit: 1823a70e65dfSChristoph Hellwig if (!IS_ERR(nd.intent.open.file)) 1824a70e65dfSChristoph Hellwig release_open_intent(&nd); 18258737f3a1SAl Viro exit_parent: 18262a737871SAl Viro if (nd.root.mnt) 18272a737871SAl Viro path_put(&nd.root); 1828a70e65dfSChristoph Hellwig path_put(&nd.path); 1829a70e65dfSChristoph Hellwig return ERR_PTR(error); 18301da177e4SLinus Torvalds 18311da177e4SLinus Torvalds do_link: 18321da177e4SLinus Torvalds error = -ELOOP; 18331da177e4SLinus Torvalds if (flag & O_NOFOLLOW) 18341da177e4SLinus Torvalds goto exit_dput; 18351da177e4SLinus Torvalds /* 18361da177e4SLinus Torvalds * This is subtle. Instead of calling do_follow_link() we do the 18371da177e4SLinus Torvalds * thing by hands. The reason is that this way we have zero link_count 18381da177e4SLinus Torvalds * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. 18391da177e4SLinus Torvalds * After that we have the parent and last component, i.e. 18401da177e4SLinus Torvalds * we are in the same situation as after the first path_walk(). 18411da177e4SLinus Torvalds * Well, almost - if the last component is normal we get its copy 18421da177e4SLinus Torvalds * stored in nd->last.name and we will have to putname() it when we 18431da177e4SLinus Torvalds * are done. Procfs-like symlinks just set LAST_BIND. 18441da177e4SLinus Torvalds */ 1845a70e65dfSChristoph Hellwig nd.flags |= LOOKUP_PARENT; 1846a70e65dfSChristoph Hellwig error = security_inode_follow_link(path.dentry, &nd); 18471da177e4SLinus Torvalds if (error) 18481da177e4SLinus Torvalds goto exit_dput; 18496de88d72SAl Viro save = nd.path; 18506de88d72SAl Viro path_get(&save); 1851a70e65dfSChristoph Hellwig error = __do_follow_link(&path, &nd); 18526de88d72SAl Viro if (error == -ESTALE) { 18536de88d72SAl Viro /* nd.path had been dropped */ 18546de88d72SAl Viro nd.path = save; 18556de88d72SAl Viro path_get(&nd.path); 18566de88d72SAl Viro nd.flags |= LOOKUP_REVAL; 18576de88d72SAl Viro error = __do_follow_link(&path, &nd); 18586de88d72SAl Viro } 18596de88d72SAl Viro path_put(&save); 1860258fa999SAl Viro path_put(&path); 1861de459215SKirill Korotaev if (error) { 1862de459215SKirill Korotaev /* Does someone understand code flow here? Or it is only 1863de459215SKirill Korotaev * me so stupid? Anathema to whoever designed this non-sense 1864de459215SKirill Korotaev * with "intent.open". 1865de459215SKirill Korotaev */ 1866a70e65dfSChristoph Hellwig release_open_intent(&nd); 1867654f562cSJ. R. Okajima if (nd.root.mnt) 1868654f562cSJ. R. Okajima path_put(&nd.root); 1869a70e65dfSChristoph Hellwig return ERR_PTR(error); 1870de459215SKirill Korotaev } 1871a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 1872a70e65dfSChristoph Hellwig if (nd.last_type == LAST_BIND) 18731da177e4SLinus Torvalds goto ok; 18741da177e4SLinus Torvalds error = -EISDIR; 1875a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM) 18761da177e4SLinus Torvalds goto exit; 1877a70e65dfSChristoph Hellwig if (nd.last.name[nd.last.len]) { 1878a70e65dfSChristoph Hellwig __putname(nd.last.name); 18791da177e4SLinus Torvalds goto exit; 18801da177e4SLinus Torvalds } 18811da177e4SLinus Torvalds error = -ELOOP; 18821da177e4SLinus Torvalds if (count++==32) { 1883a70e65dfSChristoph Hellwig __putname(nd.last.name); 18841da177e4SLinus Torvalds goto exit; 18851da177e4SLinus Torvalds } 1886a70e65dfSChristoph Hellwig dir = nd.path.dentry; 18871b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1888a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1889a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 1890a70e65dfSChristoph Hellwig __putname(nd.last.name); 18911da177e4SLinus Torvalds goto do_last; 18921da177e4SLinus Torvalds } 18931da177e4SLinus Torvalds 18941da177e4SLinus Torvalds /** 1895a70e65dfSChristoph Hellwig * filp_open - open file and return file pointer 1896a70e65dfSChristoph Hellwig * 1897a70e65dfSChristoph Hellwig * @filename: path to open 1898a70e65dfSChristoph Hellwig * @flags: open flags as per the open(2) second argument 1899a70e65dfSChristoph Hellwig * @mode: mode for the new file if O_CREAT is set, else ignored 1900a70e65dfSChristoph Hellwig * 1901a70e65dfSChristoph Hellwig * This is the helper to open a file from kernelspace if you really 1902a70e65dfSChristoph Hellwig * have to. But in generally you should not do this, so please move 1903a70e65dfSChristoph Hellwig * along, nothing to see here.. 1904a70e65dfSChristoph Hellwig */ 1905a70e65dfSChristoph Hellwig struct file *filp_open(const char *filename, int flags, int mode) 1906a70e65dfSChristoph Hellwig { 19076e8341a1SAl Viro return do_filp_open(AT_FDCWD, filename, flags, mode, 0); 1908a70e65dfSChristoph Hellwig } 1909a70e65dfSChristoph Hellwig EXPORT_SYMBOL(filp_open); 1910a70e65dfSChristoph Hellwig 1911a70e65dfSChristoph Hellwig /** 19121da177e4SLinus Torvalds * lookup_create - lookup a dentry, creating it if it doesn't exist 19131da177e4SLinus Torvalds * @nd: nameidata info 19141da177e4SLinus Torvalds * @is_dir: directory flag 19151da177e4SLinus Torvalds * 19161da177e4SLinus Torvalds * Simple function to lookup and return a dentry and create it 19171da177e4SLinus Torvalds * if it doesn't exist. Is SMP-safe. 1918c663e5d8SChristoph Hellwig * 19194ac91378SJan Blunck * Returns with nd->path.dentry->d_inode->i_mutex locked. 19201da177e4SLinus Torvalds */ 19211da177e4SLinus Torvalds struct dentry *lookup_create(struct nameidata *nd, int is_dir) 19221da177e4SLinus Torvalds { 1923c663e5d8SChristoph Hellwig struct dentry *dentry = ERR_PTR(-EEXIST); 19241da177e4SLinus Torvalds 19254ac91378SJan Blunck mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 1926c663e5d8SChristoph Hellwig /* 1927c663e5d8SChristoph Hellwig * Yucky last component or no last component at all? 1928c663e5d8SChristoph Hellwig * (foo/., foo/.., /////) 1929c663e5d8SChristoph Hellwig */ 19301da177e4SLinus Torvalds if (nd->last_type != LAST_NORM) 19311da177e4SLinus Torvalds goto fail; 19321da177e4SLinus Torvalds nd->flags &= ~LOOKUP_PARENT; 19333516586aSAl Viro nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; 1934a634904aSASANO Masahiro nd->intent.open.flags = O_EXCL; 1935c663e5d8SChristoph Hellwig 1936c663e5d8SChristoph Hellwig /* 1937c663e5d8SChristoph Hellwig * Do the final lookup. 1938c663e5d8SChristoph Hellwig */ 193949705b77SChristoph Hellwig dentry = lookup_hash(nd); 19401da177e4SLinus Torvalds if (IS_ERR(dentry)) 19411da177e4SLinus Torvalds goto fail; 1942c663e5d8SChristoph Hellwig 1943e9baf6e5SAl Viro if (dentry->d_inode) 1944e9baf6e5SAl Viro goto eexist; 1945c663e5d8SChristoph Hellwig /* 1946c663e5d8SChristoph Hellwig * Special case - lookup gave negative, but... we had foo/bar/ 1947c663e5d8SChristoph Hellwig * From the vfs_mknod() POV we just have a negative dentry - 1948c663e5d8SChristoph Hellwig * all is fine. Let's be bastards - you had / on the end, you've 1949c663e5d8SChristoph Hellwig * been asking for (non-existent) directory. -ENOENT for you. 1950c663e5d8SChristoph Hellwig */ 1951e9baf6e5SAl Viro if (unlikely(!is_dir && nd->last.name[nd->last.len])) { 19521da177e4SLinus Torvalds dput(dentry); 19531da177e4SLinus Torvalds dentry = ERR_PTR(-ENOENT); 1954e9baf6e5SAl Viro } 1955e9baf6e5SAl Viro return dentry; 1956e9baf6e5SAl Viro eexist: 1957e9baf6e5SAl Viro dput(dentry); 1958e9baf6e5SAl Viro dentry = ERR_PTR(-EEXIST); 19591da177e4SLinus Torvalds fail: 19601da177e4SLinus Torvalds return dentry; 19611da177e4SLinus Torvalds } 1962f81a0bffSChristoph Hellwig EXPORT_SYMBOL_GPL(lookup_create); 19631da177e4SLinus Torvalds 19641da177e4SLinus Torvalds int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 19651da177e4SLinus Torvalds { 1966a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 19671da177e4SLinus Torvalds 19681da177e4SLinus Torvalds if (error) 19691da177e4SLinus Torvalds return error; 19701da177e4SLinus Torvalds 19711da177e4SLinus Torvalds if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) 19721da177e4SLinus Torvalds return -EPERM; 19731da177e4SLinus Torvalds 1974acfa4380SAl Viro if (!dir->i_op->mknod) 19751da177e4SLinus Torvalds return -EPERM; 19761da177e4SLinus Torvalds 197708ce5f16SSerge E. Hallyn error = devcgroup_inode_mknod(mode, dev); 197808ce5f16SSerge E. Hallyn if (error) 197908ce5f16SSerge E. Hallyn return error; 198008ce5f16SSerge E. Hallyn 19811da177e4SLinus Torvalds error = security_inode_mknod(dir, dentry, mode, dev); 19821da177e4SLinus Torvalds if (error) 19831da177e4SLinus Torvalds return error; 19841da177e4SLinus Torvalds 19859e3509e2SJan Kara vfs_dq_init(dir); 19861da177e4SLinus Torvalds error = dir->i_op->mknod(dir, dentry, mode, dev); 1987a74574aaSStephen Smalley if (!error) 1988f38aa942SAmy Griffis fsnotify_create(dir, dentry); 19891da177e4SLinus Torvalds return error; 19901da177e4SLinus Torvalds } 19911da177e4SLinus Torvalds 1992463c3197SDave Hansen static int may_mknod(mode_t mode) 1993463c3197SDave Hansen { 1994463c3197SDave Hansen switch (mode & S_IFMT) { 1995463c3197SDave Hansen case S_IFREG: 1996463c3197SDave Hansen case S_IFCHR: 1997463c3197SDave Hansen case S_IFBLK: 1998463c3197SDave Hansen case S_IFIFO: 1999463c3197SDave Hansen case S_IFSOCK: 2000463c3197SDave Hansen case 0: /* zero mode translates to S_IFREG */ 2001463c3197SDave Hansen return 0; 2002463c3197SDave Hansen case S_IFDIR: 2003463c3197SDave Hansen return -EPERM; 2004463c3197SDave Hansen default: 2005463c3197SDave Hansen return -EINVAL; 2006463c3197SDave Hansen } 2007463c3197SDave Hansen } 2008463c3197SDave Hansen 20092e4d0924SHeiko Carstens SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, 20102e4d0924SHeiko Carstens unsigned, dev) 20111da177e4SLinus Torvalds { 20122ad94ae6SAl Viro int error; 20131da177e4SLinus Torvalds char *tmp; 20141da177e4SLinus Torvalds struct dentry *dentry; 20151da177e4SLinus Torvalds struct nameidata nd; 20161da177e4SLinus Torvalds 20171da177e4SLinus Torvalds if (S_ISDIR(mode)) 20181da177e4SLinus Torvalds return -EPERM; 20191da177e4SLinus Torvalds 20202ad94ae6SAl Viro error = user_path_parent(dfd, filename, &nd, &tmp); 20211da177e4SLinus Torvalds if (error) 20222ad94ae6SAl Viro return error; 20232ad94ae6SAl Viro 20241da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 2025463c3197SDave Hansen if (IS_ERR(dentry)) { 20261da177e4SLinus Torvalds error = PTR_ERR(dentry); 2027463c3197SDave Hansen goto out_unlock; 2028463c3197SDave Hansen } 20294ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 2030ce3b0f8dSAl Viro mode &= ~current_umask(); 2031463c3197SDave Hansen error = may_mknod(mode); 2032463c3197SDave Hansen if (error) 2033463c3197SDave Hansen goto out_dput; 2034463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2035463c3197SDave Hansen if (error) 2036463c3197SDave Hansen goto out_dput; 2037be6d3e56SKentaro Takeda error = security_path_mknod(&nd.path, dentry, mode, dev); 2038be6d3e56SKentaro Takeda if (error) 2039be6d3e56SKentaro Takeda goto out_drop_write; 20401da177e4SLinus Torvalds switch (mode & S_IFMT) { 20411da177e4SLinus Torvalds case 0: case S_IFREG: 20424ac91378SJan Blunck error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); 20431da177e4SLinus Torvalds break; 20441da177e4SLinus Torvalds case S_IFCHR: case S_IFBLK: 20454ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, 20461da177e4SLinus Torvalds new_decode_dev(dev)); 20471da177e4SLinus Torvalds break; 20481da177e4SLinus Torvalds case S_IFIFO: case S_IFSOCK: 20494ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); 20501da177e4SLinus Torvalds break; 20511da177e4SLinus Torvalds } 2052be6d3e56SKentaro Takeda out_drop_write: 2053463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2054463c3197SDave Hansen out_dput: 20551da177e4SLinus Torvalds dput(dentry); 2056463c3197SDave Hansen out_unlock: 20574ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20581d957f9bSJan Blunck path_put(&nd.path); 20591da177e4SLinus Torvalds putname(tmp); 20601da177e4SLinus Torvalds 20611da177e4SLinus Torvalds return error; 20621da177e4SLinus Torvalds } 20631da177e4SLinus Torvalds 20643480b257SHeiko Carstens SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) 20655590ff0dSUlrich Drepper { 20665590ff0dSUlrich Drepper return sys_mknodat(AT_FDCWD, filename, mode, dev); 20675590ff0dSUlrich Drepper } 20685590ff0dSUlrich Drepper 20691da177e4SLinus Torvalds int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 20701da177e4SLinus Torvalds { 2071a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 20721da177e4SLinus Torvalds 20731da177e4SLinus Torvalds if (error) 20741da177e4SLinus Torvalds return error; 20751da177e4SLinus Torvalds 2076acfa4380SAl Viro if (!dir->i_op->mkdir) 20771da177e4SLinus Torvalds return -EPERM; 20781da177e4SLinus Torvalds 20791da177e4SLinus Torvalds mode &= (S_IRWXUGO|S_ISVTX); 20801da177e4SLinus Torvalds error = security_inode_mkdir(dir, dentry, mode); 20811da177e4SLinus Torvalds if (error) 20821da177e4SLinus Torvalds return error; 20831da177e4SLinus Torvalds 20849e3509e2SJan Kara vfs_dq_init(dir); 20851da177e4SLinus Torvalds error = dir->i_op->mkdir(dir, dentry, mode); 2086a74574aaSStephen Smalley if (!error) 2087f38aa942SAmy Griffis fsnotify_mkdir(dir, dentry); 20881da177e4SLinus Torvalds return error; 20891da177e4SLinus Torvalds } 20901da177e4SLinus Torvalds 20912e4d0924SHeiko Carstens SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) 20921da177e4SLinus Torvalds { 20931da177e4SLinus Torvalds int error = 0; 20941da177e4SLinus Torvalds char * tmp; 20956902d925SDave Hansen struct dentry *dentry; 20966902d925SDave Hansen struct nameidata nd; 20971da177e4SLinus Torvalds 20982ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &tmp); 20992ad94ae6SAl Viro if (error) 21006902d925SDave Hansen goto out_err; 21011da177e4SLinus Torvalds 21021da177e4SLinus Torvalds dentry = lookup_create(&nd, 1); 21031da177e4SLinus Torvalds error = PTR_ERR(dentry); 21046902d925SDave Hansen if (IS_ERR(dentry)) 21056902d925SDave Hansen goto out_unlock; 21066902d925SDave Hansen 21074ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 2108ce3b0f8dSAl Viro mode &= ~current_umask(); 2109463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2110463c3197SDave Hansen if (error) 2111463c3197SDave Hansen goto out_dput; 2112be6d3e56SKentaro Takeda error = security_path_mkdir(&nd.path, dentry, mode); 2113be6d3e56SKentaro Takeda if (error) 2114be6d3e56SKentaro Takeda goto out_drop_write; 21154ac91378SJan Blunck error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); 2116be6d3e56SKentaro Takeda out_drop_write: 2117463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2118463c3197SDave Hansen out_dput: 21191da177e4SLinus Torvalds dput(dentry); 21206902d925SDave Hansen out_unlock: 21214ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 21221d957f9bSJan Blunck path_put(&nd.path); 21231da177e4SLinus Torvalds putname(tmp); 21246902d925SDave Hansen out_err: 21251da177e4SLinus Torvalds return error; 21261da177e4SLinus Torvalds } 21271da177e4SLinus Torvalds 21283cdad428SHeiko Carstens SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) 21295590ff0dSUlrich Drepper { 21305590ff0dSUlrich Drepper return sys_mkdirat(AT_FDCWD, pathname, mode); 21315590ff0dSUlrich Drepper } 21325590ff0dSUlrich Drepper 21331da177e4SLinus Torvalds /* 21341da177e4SLinus Torvalds * We try to drop the dentry early: we should have 21351da177e4SLinus Torvalds * a usage count of 2 if we're the only user of this 21361da177e4SLinus Torvalds * dentry, and if that is true (possibly after pruning 21371da177e4SLinus Torvalds * the dcache), then we drop the dentry now. 21381da177e4SLinus Torvalds * 21391da177e4SLinus Torvalds * A low-level filesystem can, if it choses, legally 21401da177e4SLinus Torvalds * do a 21411da177e4SLinus Torvalds * 21421da177e4SLinus Torvalds * if (!d_unhashed(dentry)) 21431da177e4SLinus Torvalds * return -EBUSY; 21441da177e4SLinus Torvalds * 21451da177e4SLinus Torvalds * if it cannot handle the case of removing a directory 21461da177e4SLinus Torvalds * that is still in use by something else.. 21471da177e4SLinus Torvalds */ 21481da177e4SLinus Torvalds void dentry_unhash(struct dentry *dentry) 21491da177e4SLinus Torvalds { 21501da177e4SLinus Torvalds dget(dentry); 21511da177e4SLinus Torvalds shrink_dcache_parent(dentry); 21521da177e4SLinus Torvalds spin_lock(&dcache_lock); 21531da177e4SLinus Torvalds spin_lock(&dentry->d_lock); 21541da177e4SLinus Torvalds if (atomic_read(&dentry->d_count) == 2) 21551da177e4SLinus Torvalds __d_drop(dentry); 21561da177e4SLinus Torvalds spin_unlock(&dentry->d_lock); 21571da177e4SLinus Torvalds spin_unlock(&dcache_lock); 21581da177e4SLinus Torvalds } 21591da177e4SLinus Torvalds 21601da177e4SLinus Torvalds int vfs_rmdir(struct inode *dir, struct dentry *dentry) 21611da177e4SLinus Torvalds { 21621da177e4SLinus Torvalds int error = may_delete(dir, dentry, 1); 21631da177e4SLinus Torvalds 21641da177e4SLinus Torvalds if (error) 21651da177e4SLinus Torvalds return error; 21661da177e4SLinus Torvalds 2167acfa4380SAl Viro if (!dir->i_op->rmdir) 21681da177e4SLinus Torvalds return -EPERM; 21691da177e4SLinus Torvalds 21709e3509e2SJan Kara vfs_dq_init(dir); 21711da177e4SLinus Torvalds 21721b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 21731da177e4SLinus Torvalds dentry_unhash(dentry); 21741da177e4SLinus Torvalds if (d_mountpoint(dentry)) 21751da177e4SLinus Torvalds error = -EBUSY; 21761da177e4SLinus Torvalds else { 21771da177e4SLinus Torvalds error = security_inode_rmdir(dir, dentry); 21781da177e4SLinus Torvalds if (!error) { 21791da177e4SLinus Torvalds error = dir->i_op->rmdir(dir, dentry); 21801da177e4SLinus Torvalds if (!error) 21811da177e4SLinus Torvalds dentry->d_inode->i_flags |= S_DEAD; 21821da177e4SLinus Torvalds } 21831da177e4SLinus Torvalds } 21841b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 21851da177e4SLinus Torvalds if (!error) { 21861da177e4SLinus Torvalds d_delete(dentry); 21871da177e4SLinus Torvalds } 21881da177e4SLinus Torvalds dput(dentry); 21891da177e4SLinus Torvalds 21901da177e4SLinus Torvalds return error; 21911da177e4SLinus Torvalds } 21921da177e4SLinus Torvalds 21935590ff0dSUlrich Drepper static long do_rmdir(int dfd, const char __user *pathname) 21941da177e4SLinus Torvalds { 21951da177e4SLinus Torvalds int error = 0; 21961da177e4SLinus Torvalds char * name; 21971da177e4SLinus Torvalds struct dentry *dentry; 21981da177e4SLinus Torvalds struct nameidata nd; 21991da177e4SLinus Torvalds 22002ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 22011da177e4SLinus Torvalds if (error) 22022ad94ae6SAl Viro return error; 22031da177e4SLinus Torvalds 22041da177e4SLinus Torvalds switch(nd.last_type) { 22051da177e4SLinus Torvalds case LAST_DOTDOT: 22061da177e4SLinus Torvalds error = -ENOTEMPTY; 22071da177e4SLinus Torvalds goto exit1; 22081da177e4SLinus Torvalds case LAST_DOT: 22091da177e4SLinus Torvalds error = -EINVAL; 22101da177e4SLinus Torvalds goto exit1; 22111da177e4SLinus Torvalds case LAST_ROOT: 22121da177e4SLinus Torvalds error = -EBUSY; 22131da177e4SLinus Torvalds goto exit1; 22141da177e4SLinus Torvalds } 22150612d9fbSOGAWA Hirofumi 22160612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 22170612d9fbSOGAWA Hirofumi 22184ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 221949705b77SChristoph Hellwig dentry = lookup_hash(&nd); 22201da177e4SLinus Torvalds error = PTR_ERR(dentry); 22216902d925SDave Hansen if (IS_ERR(dentry)) 22226902d925SDave Hansen goto exit2; 22230622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 22240622753bSDave Hansen if (error) 22250622753bSDave Hansen goto exit3; 2226be6d3e56SKentaro Takeda error = security_path_rmdir(&nd.path, dentry); 2227be6d3e56SKentaro Takeda if (error) 2228be6d3e56SKentaro Takeda goto exit4; 22294ac91378SJan Blunck error = vfs_rmdir(nd.path.dentry->d_inode, dentry); 2230be6d3e56SKentaro Takeda exit4: 22310622753bSDave Hansen mnt_drop_write(nd.path.mnt); 22320622753bSDave Hansen exit3: 22331da177e4SLinus Torvalds dput(dentry); 22346902d925SDave Hansen exit2: 22354ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22361da177e4SLinus Torvalds exit1: 22371d957f9bSJan Blunck path_put(&nd.path); 22381da177e4SLinus Torvalds putname(name); 22391da177e4SLinus Torvalds return error; 22401da177e4SLinus Torvalds } 22411da177e4SLinus Torvalds 22423cdad428SHeiko Carstens SYSCALL_DEFINE1(rmdir, const char __user *, pathname) 22435590ff0dSUlrich Drepper { 22445590ff0dSUlrich Drepper return do_rmdir(AT_FDCWD, pathname); 22455590ff0dSUlrich Drepper } 22465590ff0dSUlrich Drepper 22471da177e4SLinus Torvalds int vfs_unlink(struct inode *dir, struct dentry *dentry) 22481da177e4SLinus Torvalds { 22491da177e4SLinus Torvalds int error = may_delete(dir, dentry, 0); 22501da177e4SLinus Torvalds 22511da177e4SLinus Torvalds if (error) 22521da177e4SLinus Torvalds return error; 22531da177e4SLinus Torvalds 2254acfa4380SAl Viro if (!dir->i_op->unlink) 22551da177e4SLinus Torvalds return -EPERM; 22561da177e4SLinus Torvalds 22579e3509e2SJan Kara vfs_dq_init(dir); 22581da177e4SLinus Torvalds 22591b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 22601da177e4SLinus Torvalds if (d_mountpoint(dentry)) 22611da177e4SLinus Torvalds error = -EBUSY; 22621da177e4SLinus Torvalds else { 22631da177e4SLinus Torvalds error = security_inode_unlink(dir, dentry); 22641da177e4SLinus Torvalds if (!error) 22651da177e4SLinus Torvalds error = dir->i_op->unlink(dir, dentry); 22661da177e4SLinus Torvalds } 22671b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 22681da177e4SLinus Torvalds 22691da177e4SLinus Torvalds /* We don't d_delete() NFS sillyrenamed files--they still exist. */ 22701da177e4SLinus Torvalds if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { 2271ece95912SJan Kara fsnotify_link_count(dentry->d_inode); 22721da177e4SLinus Torvalds d_delete(dentry); 22731da177e4SLinus Torvalds } 22740eeca283SRobert Love 22751da177e4SLinus Torvalds return error; 22761da177e4SLinus Torvalds } 22771da177e4SLinus Torvalds 22781da177e4SLinus Torvalds /* 22791da177e4SLinus Torvalds * Make sure that the actual truncation of the file will occur outside its 22801b1dcc1bSJes Sorensen * directory's i_mutex. Truncate can take a long time if there is a lot of 22811da177e4SLinus Torvalds * writeout happening, and we don't want to prevent access to the directory 22821da177e4SLinus Torvalds * while waiting on the I/O. 22831da177e4SLinus Torvalds */ 22845590ff0dSUlrich Drepper static long do_unlinkat(int dfd, const char __user *pathname) 22851da177e4SLinus Torvalds { 22862ad94ae6SAl Viro int error; 22871da177e4SLinus Torvalds char *name; 22881da177e4SLinus Torvalds struct dentry *dentry; 22891da177e4SLinus Torvalds struct nameidata nd; 22901da177e4SLinus Torvalds struct inode *inode = NULL; 22911da177e4SLinus Torvalds 22922ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 22931da177e4SLinus Torvalds if (error) 22942ad94ae6SAl Viro return error; 22952ad94ae6SAl Viro 22961da177e4SLinus Torvalds error = -EISDIR; 22971da177e4SLinus Torvalds if (nd.last_type != LAST_NORM) 22981da177e4SLinus Torvalds goto exit1; 22990612d9fbSOGAWA Hirofumi 23000612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 23010612d9fbSOGAWA Hirofumi 23024ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 230349705b77SChristoph Hellwig dentry = lookup_hash(&nd); 23041da177e4SLinus Torvalds error = PTR_ERR(dentry); 23051da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 23061da177e4SLinus Torvalds /* Why not before? Because we want correct error value */ 23071da177e4SLinus Torvalds if (nd.last.name[nd.last.len]) 23081da177e4SLinus Torvalds goto slashes; 23091da177e4SLinus Torvalds inode = dentry->d_inode; 23101da177e4SLinus Torvalds if (inode) 23111da177e4SLinus Torvalds atomic_inc(&inode->i_count); 23120622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 23130622753bSDave Hansen if (error) 23140622753bSDave Hansen goto exit2; 2315be6d3e56SKentaro Takeda error = security_path_unlink(&nd.path, dentry); 2316be6d3e56SKentaro Takeda if (error) 2317be6d3e56SKentaro Takeda goto exit3; 23184ac91378SJan Blunck error = vfs_unlink(nd.path.dentry->d_inode, dentry); 2319be6d3e56SKentaro Takeda exit3: 23200622753bSDave Hansen mnt_drop_write(nd.path.mnt); 23211da177e4SLinus Torvalds exit2: 23221da177e4SLinus Torvalds dput(dentry); 23231da177e4SLinus Torvalds } 23244ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 23251da177e4SLinus Torvalds if (inode) 23261da177e4SLinus Torvalds iput(inode); /* truncate the inode here */ 23271da177e4SLinus Torvalds exit1: 23281d957f9bSJan Blunck path_put(&nd.path); 23291da177e4SLinus Torvalds putname(name); 23301da177e4SLinus Torvalds return error; 23311da177e4SLinus Torvalds 23321da177e4SLinus Torvalds slashes: 23331da177e4SLinus Torvalds error = !dentry->d_inode ? -ENOENT : 23341da177e4SLinus Torvalds S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; 23351da177e4SLinus Torvalds goto exit2; 23361da177e4SLinus Torvalds } 23371da177e4SLinus Torvalds 23382e4d0924SHeiko Carstens SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) 23395590ff0dSUlrich Drepper { 23405590ff0dSUlrich Drepper if ((flag & ~AT_REMOVEDIR) != 0) 23415590ff0dSUlrich Drepper return -EINVAL; 23425590ff0dSUlrich Drepper 23435590ff0dSUlrich Drepper if (flag & AT_REMOVEDIR) 23445590ff0dSUlrich Drepper return do_rmdir(dfd, pathname); 23455590ff0dSUlrich Drepper 23465590ff0dSUlrich Drepper return do_unlinkat(dfd, pathname); 23475590ff0dSUlrich Drepper } 23485590ff0dSUlrich Drepper 23493480b257SHeiko Carstens SYSCALL_DEFINE1(unlink, const char __user *, pathname) 23505590ff0dSUlrich Drepper { 23515590ff0dSUlrich Drepper return do_unlinkat(AT_FDCWD, pathname); 23525590ff0dSUlrich Drepper } 23535590ff0dSUlrich Drepper 2354db2e747bSMiklos Szeredi int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) 23551da177e4SLinus Torvalds { 2356a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 23571da177e4SLinus Torvalds 23581da177e4SLinus Torvalds if (error) 23591da177e4SLinus Torvalds return error; 23601da177e4SLinus Torvalds 2361acfa4380SAl Viro if (!dir->i_op->symlink) 23621da177e4SLinus Torvalds return -EPERM; 23631da177e4SLinus Torvalds 23641da177e4SLinus Torvalds error = security_inode_symlink(dir, dentry, oldname); 23651da177e4SLinus Torvalds if (error) 23661da177e4SLinus Torvalds return error; 23671da177e4SLinus Torvalds 23689e3509e2SJan Kara vfs_dq_init(dir); 23691da177e4SLinus Torvalds error = dir->i_op->symlink(dir, dentry, oldname); 2370a74574aaSStephen Smalley if (!error) 2371f38aa942SAmy Griffis fsnotify_create(dir, dentry); 23721da177e4SLinus Torvalds return error; 23731da177e4SLinus Torvalds } 23741da177e4SLinus Torvalds 23752e4d0924SHeiko Carstens SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, 23762e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 23771da177e4SLinus Torvalds { 23782ad94ae6SAl Viro int error; 23791da177e4SLinus Torvalds char *from; 23801da177e4SLinus Torvalds char *to; 23816902d925SDave Hansen struct dentry *dentry; 23826902d925SDave Hansen struct nameidata nd; 23831da177e4SLinus Torvalds 23841da177e4SLinus Torvalds from = getname(oldname); 23851da177e4SLinus Torvalds if (IS_ERR(from)) 23861da177e4SLinus Torvalds return PTR_ERR(from); 23872ad94ae6SAl Viro 23882ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 23892ad94ae6SAl Viro if (error) 23906902d925SDave Hansen goto out_putname; 23911da177e4SLinus Torvalds 23921da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 23931da177e4SLinus Torvalds error = PTR_ERR(dentry); 23946902d925SDave Hansen if (IS_ERR(dentry)) 23956902d925SDave Hansen goto out_unlock; 23966902d925SDave Hansen 239775c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 239875c3f29dSDave Hansen if (error) 239975c3f29dSDave Hansen goto out_dput; 2400be6d3e56SKentaro Takeda error = security_path_symlink(&nd.path, dentry, from); 2401be6d3e56SKentaro Takeda if (error) 2402be6d3e56SKentaro Takeda goto out_drop_write; 2403db2e747bSMiklos Szeredi error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); 2404be6d3e56SKentaro Takeda out_drop_write: 240575c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 240675c3f29dSDave Hansen out_dput: 24071da177e4SLinus Torvalds dput(dentry); 24086902d925SDave Hansen out_unlock: 24094ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 24101d957f9bSJan Blunck path_put(&nd.path); 24111da177e4SLinus Torvalds putname(to); 24126902d925SDave Hansen out_putname: 24131da177e4SLinus Torvalds putname(from); 24141da177e4SLinus Torvalds return error; 24151da177e4SLinus Torvalds } 24161da177e4SLinus Torvalds 24173480b257SHeiko Carstens SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) 24185590ff0dSUlrich Drepper { 24195590ff0dSUlrich Drepper return sys_symlinkat(oldname, AT_FDCWD, newname); 24205590ff0dSUlrich Drepper } 24215590ff0dSUlrich Drepper 24221da177e4SLinus Torvalds int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) 24231da177e4SLinus Torvalds { 24241da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 24251da177e4SLinus Torvalds int error; 24261da177e4SLinus Torvalds 24271da177e4SLinus Torvalds if (!inode) 24281da177e4SLinus Torvalds return -ENOENT; 24291da177e4SLinus Torvalds 2430a95164d9SMiklos Szeredi error = may_create(dir, new_dentry); 24311da177e4SLinus Torvalds if (error) 24321da177e4SLinus Torvalds return error; 24331da177e4SLinus Torvalds 24341da177e4SLinus Torvalds if (dir->i_sb != inode->i_sb) 24351da177e4SLinus Torvalds return -EXDEV; 24361da177e4SLinus Torvalds 24371da177e4SLinus Torvalds /* 24381da177e4SLinus Torvalds * A link to an append-only or immutable file cannot be created. 24391da177e4SLinus Torvalds */ 24401da177e4SLinus Torvalds if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) 24411da177e4SLinus Torvalds return -EPERM; 2442acfa4380SAl Viro if (!dir->i_op->link) 24431da177e4SLinus Torvalds return -EPERM; 24447e79eedbSTetsuo Handa if (S_ISDIR(inode->i_mode)) 24451da177e4SLinus Torvalds return -EPERM; 24461da177e4SLinus Torvalds 24471da177e4SLinus Torvalds error = security_inode_link(old_dentry, dir, new_dentry); 24481da177e4SLinus Torvalds if (error) 24491da177e4SLinus Torvalds return error; 24501da177e4SLinus Torvalds 24517e79eedbSTetsuo Handa mutex_lock(&inode->i_mutex); 24529e3509e2SJan Kara vfs_dq_init(dir); 24531da177e4SLinus Torvalds error = dir->i_op->link(old_dentry, dir, new_dentry); 24547e79eedbSTetsuo Handa mutex_unlock(&inode->i_mutex); 2455e31e14ecSStephen Smalley if (!error) 24567e79eedbSTetsuo Handa fsnotify_link(dir, inode, new_dentry); 24571da177e4SLinus Torvalds return error; 24581da177e4SLinus Torvalds } 24591da177e4SLinus Torvalds 24601da177e4SLinus Torvalds /* 24611da177e4SLinus Torvalds * Hardlinks are often used in delicate situations. We avoid 24621da177e4SLinus Torvalds * security-related surprises by not following symlinks on the 24631da177e4SLinus Torvalds * newname. --KAB 24641da177e4SLinus Torvalds * 24651da177e4SLinus Torvalds * We don't follow them on the oldname either to be compatible 24661da177e4SLinus Torvalds * with linux 2.0, and to avoid hard-linking to directories 24671da177e4SLinus Torvalds * and other special files. --ADM 24681da177e4SLinus Torvalds */ 24692e4d0924SHeiko Carstens SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, 24702e4d0924SHeiko Carstens int, newdfd, const char __user *, newname, int, flags) 24711da177e4SLinus Torvalds { 24721da177e4SLinus Torvalds struct dentry *new_dentry; 24732d8f3038SAl Viro struct nameidata nd; 24742d8f3038SAl Viro struct path old_path; 24751da177e4SLinus Torvalds int error; 24761da177e4SLinus Torvalds char *to; 24771da177e4SLinus Torvalds 247845c9b11aSUlrich Drepper if ((flags & ~AT_SYMLINK_FOLLOW) != 0) 2479c04030e1SUlrich Drepper return -EINVAL; 2480c04030e1SUlrich Drepper 24812d8f3038SAl Viro error = user_path_at(olddfd, oldname, 248245c9b11aSUlrich Drepper flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, 24832d8f3038SAl Viro &old_path); 24841da177e4SLinus Torvalds if (error) 24852ad94ae6SAl Viro return error; 24862ad94ae6SAl Viro 24872ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 24881da177e4SLinus Torvalds if (error) 24891da177e4SLinus Torvalds goto out; 24901da177e4SLinus Torvalds error = -EXDEV; 24912d8f3038SAl Viro if (old_path.mnt != nd.path.mnt) 24921da177e4SLinus Torvalds goto out_release; 24931da177e4SLinus Torvalds new_dentry = lookup_create(&nd, 0); 24941da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 24956902d925SDave Hansen if (IS_ERR(new_dentry)) 24966902d925SDave Hansen goto out_unlock; 249775c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 249875c3f29dSDave Hansen if (error) 249975c3f29dSDave Hansen goto out_dput; 2500be6d3e56SKentaro Takeda error = security_path_link(old_path.dentry, &nd.path, new_dentry); 2501be6d3e56SKentaro Takeda if (error) 2502be6d3e56SKentaro Takeda goto out_drop_write; 25032d8f3038SAl Viro error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); 2504be6d3e56SKentaro Takeda out_drop_write: 250575c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 250675c3f29dSDave Hansen out_dput: 25071da177e4SLinus Torvalds dput(new_dentry); 25086902d925SDave Hansen out_unlock: 25094ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 25101da177e4SLinus Torvalds out_release: 25111d957f9bSJan Blunck path_put(&nd.path); 25122ad94ae6SAl Viro putname(to); 25131da177e4SLinus Torvalds out: 25142d8f3038SAl Viro path_put(&old_path); 25151da177e4SLinus Torvalds 25161da177e4SLinus Torvalds return error; 25171da177e4SLinus Torvalds } 25181da177e4SLinus Torvalds 25193480b257SHeiko Carstens SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) 25205590ff0dSUlrich Drepper { 2521c04030e1SUlrich Drepper return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); 25225590ff0dSUlrich Drepper } 25235590ff0dSUlrich Drepper 25241da177e4SLinus Torvalds /* 25251da177e4SLinus Torvalds * The worst of all namespace operations - renaming directory. "Perverted" 25261da177e4SLinus Torvalds * doesn't even start to describe it. Somebody in UCB had a heck of a trip... 25271da177e4SLinus Torvalds * Problems: 25281da177e4SLinus Torvalds * a) we can get into loop creation. Check is done in is_subdir(). 25291da177e4SLinus Torvalds * b) race potential - two innocent renames can create a loop together. 25301da177e4SLinus Torvalds * That's where 4.4 screws up. Current fix: serialization on 2531a11f3a05SArjan van de Ven * sb->s_vfs_rename_mutex. We might be more accurate, but that's another 25321da177e4SLinus Torvalds * story. 25331da177e4SLinus Torvalds * c) we have to lock _three_ objects - parents and victim (if it exists). 25341b1dcc1bSJes Sorensen * And that - after we got ->i_mutex on parents (until then we don't know 25351da177e4SLinus Torvalds * whether the target exists). Solution: try to be smart with locking 25361da177e4SLinus Torvalds * order for inodes. We rely on the fact that tree topology may change 2537a11f3a05SArjan van de Ven * only under ->s_vfs_rename_mutex _and_ that parent of the object we 25381da177e4SLinus Torvalds * move will be locked. Thus we can rank directories by the tree 25391da177e4SLinus Torvalds * (ancestors first) and rank all non-directories after them. 25401da177e4SLinus Torvalds * That works since everybody except rename does "lock parent, lookup, 2541a11f3a05SArjan van de Ven * lock child" and rename is under ->s_vfs_rename_mutex. 25421da177e4SLinus Torvalds * HOWEVER, it relies on the assumption that any object with ->lookup() 25431da177e4SLinus Torvalds * has no more than 1 dentry. If "hybrid" objects will ever appear, 25441da177e4SLinus Torvalds * we'd better make sure that there's no link(2) for them. 25451da177e4SLinus Torvalds * d) some filesystems don't support opened-but-unlinked directories, 25461da177e4SLinus Torvalds * either because of layout or because they are not ready to deal with 25471da177e4SLinus Torvalds * all cases correctly. The latter will be fixed (taking this sort of 25481da177e4SLinus Torvalds * stuff into VFS), but the former is not going away. Solution: the same 25491da177e4SLinus Torvalds * trick as in rmdir(). 25501da177e4SLinus Torvalds * e) conversion from fhandle to dentry may come in the wrong moment - when 25511b1dcc1bSJes Sorensen * we are removing the target. Solution: we will have to grab ->i_mutex 25521da177e4SLinus Torvalds * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on 25531b1dcc1bSJes Sorensen * ->i_mutex on parents, which works but leads to some truely excessive 25541da177e4SLinus Torvalds * locking]. 25551da177e4SLinus Torvalds */ 255675c96f85SAdrian Bunk static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, 25571da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25581da177e4SLinus Torvalds { 25591da177e4SLinus Torvalds int error = 0; 25601da177e4SLinus Torvalds struct inode *target; 25611da177e4SLinus Torvalds 25621da177e4SLinus Torvalds /* 25631da177e4SLinus Torvalds * If we are going to change the parent - check write permissions, 25641da177e4SLinus Torvalds * we'll need to flip '..'. 25651da177e4SLinus Torvalds */ 25661da177e4SLinus Torvalds if (new_dir != old_dir) { 2567f419a2e3SAl Viro error = inode_permission(old_dentry->d_inode, MAY_WRITE); 25681da177e4SLinus Torvalds if (error) 25691da177e4SLinus Torvalds return error; 25701da177e4SLinus Torvalds } 25711da177e4SLinus Torvalds 25721da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25731da177e4SLinus Torvalds if (error) 25741da177e4SLinus Torvalds return error; 25751da177e4SLinus Torvalds 25761da177e4SLinus Torvalds target = new_dentry->d_inode; 25771da177e4SLinus Torvalds if (target) { 25781b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25791da177e4SLinus Torvalds dentry_unhash(new_dentry); 25801da177e4SLinus Torvalds } 25811da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25821da177e4SLinus Torvalds error = -EBUSY; 25831da177e4SLinus Torvalds else 25841da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25851da177e4SLinus Torvalds if (target) { 25861da177e4SLinus Torvalds if (!error) 25871da177e4SLinus Torvalds target->i_flags |= S_DEAD; 25881b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25891da177e4SLinus Torvalds if (d_unhashed(new_dentry)) 25901da177e4SLinus Torvalds d_rehash(new_dentry); 25911da177e4SLinus Torvalds dput(new_dentry); 25921da177e4SLinus Torvalds } 2593e31e14ecSStephen Smalley if (!error) 2594349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25951da177e4SLinus Torvalds d_move(old_dentry,new_dentry); 25961da177e4SLinus Torvalds return error; 25971da177e4SLinus Torvalds } 25981da177e4SLinus Torvalds 259975c96f85SAdrian Bunk static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, 26001da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 26011da177e4SLinus Torvalds { 26021da177e4SLinus Torvalds struct inode *target; 26031da177e4SLinus Torvalds int error; 26041da177e4SLinus Torvalds 26051da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 26061da177e4SLinus Torvalds if (error) 26071da177e4SLinus Torvalds return error; 26081da177e4SLinus Torvalds 26091da177e4SLinus Torvalds dget(new_dentry); 26101da177e4SLinus Torvalds target = new_dentry->d_inode; 26111da177e4SLinus Torvalds if (target) 26121b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 26131da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 26141da177e4SLinus Torvalds error = -EBUSY; 26151da177e4SLinus Torvalds else 26161da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 26171da177e4SLinus Torvalds if (!error) { 2618349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 26191da177e4SLinus Torvalds d_move(old_dentry, new_dentry); 26201da177e4SLinus Torvalds } 26211da177e4SLinus Torvalds if (target) 26221b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 26231da177e4SLinus Torvalds dput(new_dentry); 26241da177e4SLinus Torvalds return error; 26251da177e4SLinus Torvalds } 26261da177e4SLinus Torvalds 26271da177e4SLinus Torvalds int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 26281da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 26291da177e4SLinus Torvalds { 26301da177e4SLinus Torvalds int error; 26311da177e4SLinus Torvalds int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); 26320eeca283SRobert Love const char *old_name; 26331da177e4SLinus Torvalds 26341da177e4SLinus Torvalds if (old_dentry->d_inode == new_dentry->d_inode) 26351da177e4SLinus Torvalds return 0; 26361da177e4SLinus Torvalds 26371da177e4SLinus Torvalds error = may_delete(old_dir, old_dentry, is_dir); 26381da177e4SLinus Torvalds if (error) 26391da177e4SLinus Torvalds return error; 26401da177e4SLinus Torvalds 26411da177e4SLinus Torvalds if (!new_dentry->d_inode) 2642a95164d9SMiklos Szeredi error = may_create(new_dir, new_dentry); 26431da177e4SLinus Torvalds else 26441da177e4SLinus Torvalds error = may_delete(new_dir, new_dentry, is_dir); 26451da177e4SLinus Torvalds if (error) 26461da177e4SLinus Torvalds return error; 26471da177e4SLinus Torvalds 2648acfa4380SAl Viro if (!old_dir->i_op->rename) 26491da177e4SLinus Torvalds return -EPERM; 26501da177e4SLinus Torvalds 26519e3509e2SJan Kara vfs_dq_init(old_dir); 26529e3509e2SJan Kara vfs_dq_init(new_dir); 26531da177e4SLinus Torvalds 26540eeca283SRobert Love old_name = fsnotify_oldname_init(old_dentry->d_name.name); 26550eeca283SRobert Love 26561da177e4SLinus Torvalds if (is_dir) 26571da177e4SLinus Torvalds error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); 26581da177e4SLinus Torvalds else 26591da177e4SLinus Torvalds error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); 26601da177e4SLinus Torvalds if (!error) { 26610eeca283SRobert Love const char *new_name = old_dentry->d_name.name; 266289204c40SJohn McCutchan fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, 26635a190ae6SAl Viro new_dentry->d_inode, old_dentry); 26641da177e4SLinus Torvalds } 26650eeca283SRobert Love fsnotify_oldname_free(old_name); 26660eeca283SRobert Love 26671da177e4SLinus Torvalds return error; 26681da177e4SLinus Torvalds } 26691da177e4SLinus Torvalds 26702e4d0924SHeiko Carstens SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, 26712e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 26721da177e4SLinus Torvalds { 26731da177e4SLinus Torvalds struct dentry *old_dir, *new_dir; 26741da177e4SLinus Torvalds struct dentry *old_dentry, *new_dentry; 26751da177e4SLinus Torvalds struct dentry *trap; 26761da177e4SLinus Torvalds struct nameidata oldnd, newnd; 26772ad94ae6SAl Viro char *from; 26782ad94ae6SAl Viro char *to; 26792ad94ae6SAl Viro int error; 26801da177e4SLinus Torvalds 26812ad94ae6SAl Viro error = user_path_parent(olddfd, oldname, &oldnd, &from); 26821da177e4SLinus Torvalds if (error) 26831da177e4SLinus Torvalds goto exit; 26841da177e4SLinus Torvalds 26852ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &newnd, &to); 26861da177e4SLinus Torvalds if (error) 26871da177e4SLinus Torvalds goto exit1; 26881da177e4SLinus Torvalds 26891da177e4SLinus Torvalds error = -EXDEV; 26904ac91378SJan Blunck if (oldnd.path.mnt != newnd.path.mnt) 26911da177e4SLinus Torvalds goto exit2; 26921da177e4SLinus Torvalds 26934ac91378SJan Blunck old_dir = oldnd.path.dentry; 26941da177e4SLinus Torvalds error = -EBUSY; 26951da177e4SLinus Torvalds if (oldnd.last_type != LAST_NORM) 26961da177e4SLinus Torvalds goto exit2; 26971da177e4SLinus Torvalds 26984ac91378SJan Blunck new_dir = newnd.path.dentry; 26991da177e4SLinus Torvalds if (newnd.last_type != LAST_NORM) 27001da177e4SLinus Torvalds goto exit2; 27011da177e4SLinus Torvalds 27020612d9fbSOGAWA Hirofumi oldnd.flags &= ~LOOKUP_PARENT; 27030612d9fbSOGAWA Hirofumi newnd.flags &= ~LOOKUP_PARENT; 27044e9ed2f8SOGAWA Hirofumi newnd.flags |= LOOKUP_RENAME_TARGET; 27050612d9fbSOGAWA Hirofumi 27061da177e4SLinus Torvalds trap = lock_rename(new_dir, old_dir); 27071da177e4SLinus Torvalds 270849705b77SChristoph Hellwig old_dentry = lookup_hash(&oldnd); 27091da177e4SLinus Torvalds error = PTR_ERR(old_dentry); 27101da177e4SLinus Torvalds if (IS_ERR(old_dentry)) 27111da177e4SLinus Torvalds goto exit3; 27121da177e4SLinus Torvalds /* source must exist */ 27131da177e4SLinus Torvalds error = -ENOENT; 27141da177e4SLinus Torvalds if (!old_dentry->d_inode) 27151da177e4SLinus Torvalds goto exit4; 27161da177e4SLinus Torvalds /* unless the source is a directory trailing slashes give -ENOTDIR */ 27171da177e4SLinus Torvalds if (!S_ISDIR(old_dentry->d_inode->i_mode)) { 27181da177e4SLinus Torvalds error = -ENOTDIR; 27191da177e4SLinus Torvalds if (oldnd.last.name[oldnd.last.len]) 27201da177e4SLinus Torvalds goto exit4; 27211da177e4SLinus Torvalds if (newnd.last.name[newnd.last.len]) 27221da177e4SLinus Torvalds goto exit4; 27231da177e4SLinus Torvalds } 27241da177e4SLinus Torvalds /* source should not be ancestor of target */ 27251da177e4SLinus Torvalds error = -EINVAL; 27261da177e4SLinus Torvalds if (old_dentry == trap) 27271da177e4SLinus Torvalds goto exit4; 272849705b77SChristoph Hellwig new_dentry = lookup_hash(&newnd); 27291da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 27301da177e4SLinus Torvalds if (IS_ERR(new_dentry)) 27311da177e4SLinus Torvalds goto exit4; 27321da177e4SLinus Torvalds /* target should not be an ancestor of source */ 27331da177e4SLinus Torvalds error = -ENOTEMPTY; 27341da177e4SLinus Torvalds if (new_dentry == trap) 27351da177e4SLinus Torvalds goto exit5; 27361da177e4SLinus Torvalds 27379079b1ebSDave Hansen error = mnt_want_write(oldnd.path.mnt); 27389079b1ebSDave Hansen if (error) 27399079b1ebSDave Hansen goto exit5; 2740be6d3e56SKentaro Takeda error = security_path_rename(&oldnd.path, old_dentry, 2741be6d3e56SKentaro Takeda &newnd.path, new_dentry); 2742be6d3e56SKentaro Takeda if (error) 2743be6d3e56SKentaro Takeda goto exit6; 27441da177e4SLinus Torvalds error = vfs_rename(old_dir->d_inode, old_dentry, 27451da177e4SLinus Torvalds new_dir->d_inode, new_dentry); 2746be6d3e56SKentaro Takeda exit6: 27479079b1ebSDave Hansen mnt_drop_write(oldnd.path.mnt); 27481da177e4SLinus Torvalds exit5: 27491da177e4SLinus Torvalds dput(new_dentry); 27501da177e4SLinus Torvalds exit4: 27511da177e4SLinus Torvalds dput(old_dentry); 27521da177e4SLinus Torvalds exit3: 27531da177e4SLinus Torvalds unlock_rename(new_dir, old_dir); 27541da177e4SLinus Torvalds exit2: 27551d957f9bSJan Blunck path_put(&newnd.path); 27562ad94ae6SAl Viro putname(to); 27571da177e4SLinus Torvalds exit1: 27581d957f9bSJan Blunck path_put(&oldnd.path); 27591da177e4SLinus Torvalds putname(from); 27602ad94ae6SAl Viro exit: 27611da177e4SLinus Torvalds return error; 27621da177e4SLinus Torvalds } 27631da177e4SLinus Torvalds 2764a26eab24SHeiko Carstens SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) 27655590ff0dSUlrich Drepper { 27665590ff0dSUlrich Drepper return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); 27675590ff0dSUlrich Drepper } 27685590ff0dSUlrich Drepper 27691da177e4SLinus Torvalds int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) 27701da177e4SLinus Torvalds { 27711da177e4SLinus Torvalds int len; 27721da177e4SLinus Torvalds 27731da177e4SLinus Torvalds len = PTR_ERR(link); 27741da177e4SLinus Torvalds if (IS_ERR(link)) 27751da177e4SLinus Torvalds goto out; 27761da177e4SLinus Torvalds 27771da177e4SLinus Torvalds len = strlen(link); 27781da177e4SLinus Torvalds if (len > (unsigned) buflen) 27791da177e4SLinus Torvalds len = buflen; 27801da177e4SLinus Torvalds if (copy_to_user(buffer, link, len)) 27811da177e4SLinus Torvalds len = -EFAULT; 27821da177e4SLinus Torvalds out: 27831da177e4SLinus Torvalds return len; 27841da177e4SLinus Torvalds } 27851da177e4SLinus Torvalds 27861da177e4SLinus Torvalds /* 27871da177e4SLinus Torvalds * A helper for ->readlink(). This should be used *ONLY* for symlinks that 27881da177e4SLinus Torvalds * have ->follow_link() touching nd only in nd_set_link(). Using (or not 27891da177e4SLinus Torvalds * using) it for any given inode is up to filesystem. 27901da177e4SLinus Torvalds */ 27911da177e4SLinus Torvalds int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27921da177e4SLinus Torvalds { 27931da177e4SLinus Torvalds struct nameidata nd; 2794cc314eefSLinus Torvalds void *cookie; 2795694a1764SMarcin Slusarz int res; 2796cc314eefSLinus Torvalds 27971da177e4SLinus Torvalds nd.depth = 0; 2798cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); 2799694a1764SMarcin Slusarz if (IS_ERR(cookie)) 2800694a1764SMarcin Slusarz return PTR_ERR(cookie); 2801694a1764SMarcin Slusarz 2802694a1764SMarcin Slusarz res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); 28031da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 2804cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, &nd, cookie); 2805694a1764SMarcin Slusarz return res; 28061da177e4SLinus Torvalds } 28071da177e4SLinus Torvalds 28081da177e4SLinus Torvalds int vfs_follow_link(struct nameidata *nd, const char *link) 28091da177e4SLinus Torvalds { 28101da177e4SLinus Torvalds return __vfs_follow_link(nd, link); 28111da177e4SLinus Torvalds } 28121da177e4SLinus Torvalds 28131da177e4SLinus Torvalds /* get the link contents into pagecache */ 28141da177e4SLinus Torvalds static char *page_getlink(struct dentry * dentry, struct page **ppage) 28151da177e4SLinus Torvalds { 2816ebd09abbSDuane Griffin char *kaddr; 28171da177e4SLinus Torvalds struct page *page; 28181da177e4SLinus Torvalds struct address_space *mapping = dentry->d_inode->i_mapping; 2819090d2b18SPekka Enberg page = read_mapping_page(mapping, 0, NULL); 28201da177e4SLinus Torvalds if (IS_ERR(page)) 28216fe6900eSNick Piggin return (char*)page; 28221da177e4SLinus Torvalds *ppage = page; 2823ebd09abbSDuane Griffin kaddr = kmap(page); 2824ebd09abbSDuane Griffin nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); 2825ebd09abbSDuane Griffin return kaddr; 28261da177e4SLinus Torvalds } 28271da177e4SLinus Torvalds 28281da177e4SLinus Torvalds int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) 28291da177e4SLinus Torvalds { 28301da177e4SLinus Torvalds struct page *page = NULL; 28311da177e4SLinus Torvalds char *s = page_getlink(dentry, &page); 28321da177e4SLinus Torvalds int res = vfs_readlink(dentry,buffer,buflen,s); 28331da177e4SLinus Torvalds if (page) { 28341da177e4SLinus Torvalds kunmap(page); 28351da177e4SLinus Torvalds page_cache_release(page); 28361da177e4SLinus Torvalds } 28371da177e4SLinus Torvalds return res; 28381da177e4SLinus Torvalds } 28391da177e4SLinus Torvalds 2840cc314eefSLinus Torvalds void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) 28411da177e4SLinus Torvalds { 2842cc314eefSLinus Torvalds struct page *page = NULL; 28431da177e4SLinus Torvalds nd_set_link(nd, page_getlink(dentry, &page)); 2844cc314eefSLinus Torvalds return page; 28451da177e4SLinus Torvalds } 28461da177e4SLinus Torvalds 2847cc314eefSLinus Torvalds void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 28481da177e4SLinus Torvalds { 2849cc314eefSLinus Torvalds struct page *page = cookie; 2850cc314eefSLinus Torvalds 2851cc314eefSLinus Torvalds if (page) { 28521da177e4SLinus Torvalds kunmap(page); 28531da177e4SLinus Torvalds page_cache_release(page); 28541da177e4SLinus Torvalds } 28551da177e4SLinus Torvalds } 28561da177e4SLinus Torvalds 285754566b2cSNick Piggin /* 285854566b2cSNick Piggin * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS 285954566b2cSNick Piggin */ 286054566b2cSNick Piggin int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) 28611da177e4SLinus Torvalds { 28621da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 28630adb25d2SKirill Korotaev struct page *page; 2864afddba49SNick Piggin void *fsdata; 2865beb497abSDmitriy Monakhov int err; 28661da177e4SLinus Torvalds char *kaddr; 286754566b2cSNick Piggin unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; 286854566b2cSNick Piggin if (nofs) 286954566b2cSNick Piggin flags |= AOP_FLAG_NOFS; 28701da177e4SLinus Torvalds 28717e53cac4SNeilBrown retry: 2872afddba49SNick Piggin err = pagecache_write_begin(NULL, mapping, 0, len-1, 287354566b2cSNick Piggin flags, &page, &fsdata); 28741da177e4SLinus Torvalds if (err) 2875afddba49SNick Piggin goto fail; 2876afddba49SNick Piggin 28771da177e4SLinus Torvalds kaddr = kmap_atomic(page, KM_USER0); 28781da177e4SLinus Torvalds memcpy(kaddr, symname, len-1); 28791da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 2880afddba49SNick Piggin 2881afddba49SNick Piggin err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, 2882afddba49SNick Piggin page, fsdata); 28831da177e4SLinus Torvalds if (err < 0) 28841da177e4SLinus Torvalds goto fail; 2885afddba49SNick Piggin if (err < len-1) 2886afddba49SNick Piggin goto retry; 2887afddba49SNick Piggin 28881da177e4SLinus Torvalds mark_inode_dirty(inode); 28891da177e4SLinus Torvalds return 0; 28901da177e4SLinus Torvalds fail: 28911da177e4SLinus Torvalds return err; 28921da177e4SLinus Torvalds } 28931da177e4SLinus Torvalds 28940adb25d2SKirill Korotaev int page_symlink(struct inode *inode, const char *symname, int len) 28950adb25d2SKirill Korotaev { 28960adb25d2SKirill Korotaev return __page_symlink(inode, symname, len, 289754566b2cSNick Piggin !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); 28980adb25d2SKirill Korotaev } 28990adb25d2SKirill Korotaev 290092e1d5beSArjan van de Ven const struct inode_operations page_symlink_inode_operations = { 29011da177e4SLinus Torvalds .readlink = generic_readlink, 29021da177e4SLinus Torvalds .follow_link = page_follow_link_light, 29031da177e4SLinus Torvalds .put_link = page_put_link, 29041da177e4SLinus Torvalds }; 29051da177e4SLinus Torvalds 29062d8f3038SAl Viro EXPORT_SYMBOL(user_path_at); 29071da177e4SLinus Torvalds EXPORT_SYMBOL(follow_down); 29081da177e4SLinus Torvalds EXPORT_SYMBOL(follow_up); 29091da177e4SLinus Torvalds EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ 29101da177e4SLinus Torvalds EXPORT_SYMBOL(getname); 29111da177e4SLinus Torvalds EXPORT_SYMBOL(lock_rename); 29121da177e4SLinus Torvalds EXPORT_SYMBOL(lookup_one_len); 29131da177e4SLinus Torvalds EXPORT_SYMBOL(page_follow_link_light); 29141da177e4SLinus Torvalds EXPORT_SYMBOL(page_put_link); 29151da177e4SLinus Torvalds EXPORT_SYMBOL(page_readlink); 29160adb25d2SKirill Korotaev EXPORT_SYMBOL(__page_symlink); 29171da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink); 29181da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink_inode_operations); 29191da177e4SLinus Torvalds EXPORT_SYMBOL(path_lookup); 2920d1811465SAl Viro EXPORT_SYMBOL(kern_path); 292116f18200SJosef 'Jeff' Sipek EXPORT_SYMBOL(vfs_path_lookup); 2922f419a2e3SAl Viro EXPORT_SYMBOL(inode_permission); 29238c744fb8SChristoph Hellwig EXPORT_SYMBOL(file_permission); 29241da177e4SLinus Torvalds EXPORT_SYMBOL(unlock_rename); 29251da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_create); 29261da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_follow_link); 29271da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_link); 29281da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mkdir); 29291da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mknod); 29301da177e4SLinus Torvalds EXPORT_SYMBOL(generic_permission); 29311da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_readlink); 29321da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rename); 29331da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rmdir); 29341da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_symlink); 29351da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_unlink); 29361da177e4SLinus Torvalds EXPORT_SYMBOL(dentry_unhash); 29371da177e4SLinus Torvalds EXPORT_SYMBOL(generic_readlink); 2938