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 111a02f76c3SAl Viro static int __link_path_walk(const char *name, struct nameidata *nd); 112c4a7808fSJosef 'Jeff' Sipek 1131da177e4SLinus Torvalds /* In order to reduce some races, while at the same time doing additional 1141da177e4SLinus Torvalds * checking and hopefully speeding things up, we copy filenames to the 1151da177e4SLinus Torvalds * kernel data space before using them.. 1161da177e4SLinus Torvalds * 1171da177e4SLinus Torvalds * POSIX.1 2.4: an empty pathname is invalid (ENOENT). 1181da177e4SLinus Torvalds * PATH_MAX includes the nul terminator --RR. 1191da177e4SLinus Torvalds */ 120858119e1SArjan van de Ven static int do_getname(const char __user *filename, char *page) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds int retval; 1231da177e4SLinus Torvalds unsigned long len = PATH_MAX; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds if (!segment_eq(get_fs(), KERNEL_DS)) { 1261da177e4SLinus Torvalds if ((unsigned long) filename >= TASK_SIZE) 1271da177e4SLinus Torvalds return -EFAULT; 1281da177e4SLinus Torvalds if (TASK_SIZE - (unsigned long) filename < PATH_MAX) 1291da177e4SLinus Torvalds len = TASK_SIZE - (unsigned long) filename; 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds 1321da177e4SLinus Torvalds retval = strncpy_from_user(page, filename, len); 1331da177e4SLinus Torvalds if (retval > 0) { 1341da177e4SLinus Torvalds if (retval < len) 1351da177e4SLinus Torvalds return 0; 1361da177e4SLinus Torvalds return -ENAMETOOLONG; 1371da177e4SLinus Torvalds } else if (!retval) 1381da177e4SLinus Torvalds retval = -ENOENT; 1391da177e4SLinus Torvalds return retval; 1401da177e4SLinus Torvalds } 1411da177e4SLinus Torvalds 1421da177e4SLinus Torvalds char * getname(const char __user * filename) 1431da177e4SLinus Torvalds { 1441da177e4SLinus Torvalds char *tmp, *result; 1451da177e4SLinus Torvalds 1461da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 1471da177e4SLinus Torvalds tmp = __getname(); 1481da177e4SLinus Torvalds if (tmp) { 1491da177e4SLinus Torvalds int retval = do_getname(filename, tmp); 1501da177e4SLinus Torvalds 1511da177e4SLinus Torvalds result = tmp; 1521da177e4SLinus Torvalds if (retval < 0) { 1531da177e4SLinus Torvalds __putname(tmp); 1541da177e4SLinus Torvalds result = ERR_PTR(retval); 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds } 1571da177e4SLinus Torvalds audit_getname(result); 1581da177e4SLinus Torvalds return result; 1591da177e4SLinus Torvalds } 1601da177e4SLinus Torvalds 1611da177e4SLinus Torvalds #ifdef CONFIG_AUDITSYSCALL 1621da177e4SLinus Torvalds void putname(const char *name) 1631da177e4SLinus Torvalds { 1645ac3a9c2SAl Viro if (unlikely(!audit_dummy_context())) 1651da177e4SLinus Torvalds audit_putname(name); 1661da177e4SLinus Torvalds else 1671da177e4SLinus Torvalds __putname(name); 1681da177e4SLinus Torvalds } 1691da177e4SLinus Torvalds EXPORT_SYMBOL(putname); 1701da177e4SLinus Torvalds #endif 1711da177e4SLinus Torvalds 1721da177e4SLinus Torvalds 1731da177e4SLinus Torvalds /** 1741da177e4SLinus Torvalds * generic_permission - check for access rights on a Posix-like filesystem 1751da177e4SLinus Torvalds * @inode: inode to check access rights for 1761da177e4SLinus Torvalds * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 1771da177e4SLinus Torvalds * @check_acl: optional callback to check for Posix ACLs 1781da177e4SLinus Torvalds * 1791da177e4SLinus Torvalds * Used to check for read/write/execute permissions on a file. 1801da177e4SLinus Torvalds * We use "fsuid" for this, letting us set arbitrary permissions 1811da177e4SLinus Torvalds * for filesystem access without changing the "normal" uids which 1821da177e4SLinus Torvalds * are used for other things.. 1831da177e4SLinus Torvalds */ 1841da177e4SLinus Torvalds int generic_permission(struct inode *inode, int mask, 1851da177e4SLinus Torvalds int (*check_acl)(struct inode *inode, int mask)) 1861da177e4SLinus Torvalds { 1871da177e4SLinus Torvalds umode_t mode = inode->i_mode; 1881da177e4SLinus Torvalds 189e6305c43SAl Viro mask &= MAY_READ | MAY_WRITE | MAY_EXEC; 190e6305c43SAl Viro 191da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 1921da177e4SLinus Torvalds mode >>= 6; 1931da177e4SLinus Torvalds else { 1941da177e4SLinus Torvalds if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { 1951da177e4SLinus Torvalds int error = check_acl(inode, mask); 1961da177e4SLinus Torvalds if (error == -EACCES) 1971da177e4SLinus Torvalds goto check_capabilities; 1981da177e4SLinus Torvalds else if (error != -EAGAIN) 1991da177e4SLinus Torvalds return error; 2001da177e4SLinus Torvalds } 2011da177e4SLinus Torvalds 2021da177e4SLinus Torvalds if (in_group_p(inode->i_gid)) 2031da177e4SLinus Torvalds mode >>= 3; 2041da177e4SLinus Torvalds } 2051da177e4SLinus Torvalds 2061da177e4SLinus Torvalds /* 2071da177e4SLinus Torvalds * If the DACs are ok we don't need any capability check. 2081da177e4SLinus Torvalds */ 209e6305c43SAl Viro if ((mask & ~mode) == 0) 2101da177e4SLinus Torvalds return 0; 2111da177e4SLinus Torvalds 2121da177e4SLinus Torvalds check_capabilities: 2131da177e4SLinus Torvalds /* 2141da177e4SLinus Torvalds * Read/write DACs are always overridable. 2151da177e4SLinus Torvalds * Executable DACs are overridable if at least one exec bit is set. 2161da177e4SLinus Torvalds */ 217f696a365SMiklos Szeredi if (!(mask & MAY_EXEC) || execute_ok(inode)) 2181da177e4SLinus Torvalds if (capable(CAP_DAC_OVERRIDE)) 2191da177e4SLinus Torvalds return 0; 2201da177e4SLinus Torvalds 2211da177e4SLinus Torvalds /* 2221da177e4SLinus Torvalds * Searching includes executable on directories, else just read. 2231da177e4SLinus Torvalds */ 2241da177e4SLinus Torvalds if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) 2251da177e4SLinus Torvalds if (capable(CAP_DAC_READ_SEARCH)) 2261da177e4SLinus Torvalds return 0; 2271da177e4SLinus Torvalds 2281da177e4SLinus Torvalds return -EACCES; 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 231cb23beb5SChristoph Hellwig /** 232cb23beb5SChristoph Hellwig * inode_permission - check for access rights to a given inode 233cb23beb5SChristoph Hellwig * @inode: inode to check permission on 234cb23beb5SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 235cb23beb5SChristoph Hellwig * 236cb23beb5SChristoph Hellwig * Used to check for read/write/execute permissions on an inode. 237cb23beb5SChristoph Hellwig * We use "fsuid" for this, letting us set arbitrary permissions 238cb23beb5SChristoph Hellwig * for filesystem access without changing the "normal" uids which 239cb23beb5SChristoph Hellwig * are used for other things. 240cb23beb5SChristoph Hellwig */ 241f419a2e3SAl Viro int inode_permission(struct inode *inode, int mask) 2421da177e4SLinus Torvalds { 243e6305c43SAl Viro int retval; 2441da177e4SLinus Torvalds 2451da177e4SLinus Torvalds if (mask & MAY_WRITE) { 24622590e41SMiklos Szeredi umode_t mode = inode->i_mode; 2471da177e4SLinus Torvalds 2481da177e4SLinus Torvalds /* 2491da177e4SLinus Torvalds * Nobody gets write access to a read-only fs. 2501da177e4SLinus Torvalds */ 2511da177e4SLinus Torvalds if (IS_RDONLY(inode) && 2521da177e4SLinus Torvalds (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) 2531da177e4SLinus Torvalds return -EROFS; 2541da177e4SLinus Torvalds 2551da177e4SLinus Torvalds /* 2561da177e4SLinus Torvalds * Nobody gets write access to an immutable file. 2571da177e4SLinus Torvalds */ 2581da177e4SLinus Torvalds if (IS_IMMUTABLE(inode)) 2591da177e4SLinus Torvalds return -EACCES; 2601da177e4SLinus Torvalds } 2611da177e4SLinus Torvalds 262acfa4380SAl Viro if (inode->i_op->permission) 263b77b0646SAl Viro retval = inode->i_op->permission(inode, mask); 264f696a365SMiklos Szeredi else 265e6305c43SAl Viro retval = generic_permission(inode, mask, NULL); 266f696a365SMiklos Szeredi 2671da177e4SLinus Torvalds if (retval) 2681da177e4SLinus Torvalds return retval; 2691da177e4SLinus Torvalds 27008ce5f16SSerge E. Hallyn retval = devcgroup_inode_permission(inode, mask); 27108ce5f16SSerge E. Hallyn if (retval) 27208ce5f16SSerge E. Hallyn return retval; 27308ce5f16SSerge E. Hallyn 274e6305c43SAl Viro return security_inode_permission(inode, 275f418b006SStephen Smalley mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)); 2761da177e4SLinus Torvalds } 2771da177e4SLinus Torvalds 278e4543eddSChristoph Hellwig /** 2798c744fb8SChristoph Hellwig * file_permission - check for additional access rights to a given file 2808c744fb8SChristoph Hellwig * @file: file to check access rights for 2818c744fb8SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 2828c744fb8SChristoph Hellwig * 2838c744fb8SChristoph Hellwig * Used to check for read/write/execute permissions on an already opened 2848c744fb8SChristoph Hellwig * file. 2858c744fb8SChristoph Hellwig * 2868c744fb8SChristoph Hellwig * Note: 2878c744fb8SChristoph Hellwig * Do not use this function in new code. All access checks should 288cb23beb5SChristoph Hellwig * be done using inode_permission(). 2898c744fb8SChristoph Hellwig */ 2908c744fb8SChristoph Hellwig int file_permission(struct file *file, int mask) 2918c744fb8SChristoph Hellwig { 292f419a2e3SAl Viro return inode_permission(file->f_path.dentry->d_inode, mask); 2938c744fb8SChristoph Hellwig } 2948c744fb8SChristoph Hellwig 2951da177e4SLinus Torvalds /* 2961da177e4SLinus Torvalds * get_write_access() gets write permission for a file. 2971da177e4SLinus Torvalds * put_write_access() releases this write permission. 2981da177e4SLinus Torvalds * This is used for regular files. 2991da177e4SLinus Torvalds * We cannot support write (and maybe mmap read-write shared) accesses and 3001da177e4SLinus Torvalds * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode 3011da177e4SLinus Torvalds * can have the following values: 3021da177e4SLinus Torvalds * 0: no writers, no VM_DENYWRITE mappings 3031da177e4SLinus Torvalds * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist 3041da177e4SLinus Torvalds * > 0: (i_writecount) users are writing to the file. 3051da177e4SLinus Torvalds * 3061da177e4SLinus Torvalds * Normally we operate on that counter with atomic_{inc,dec} and it's safe 3071da177e4SLinus Torvalds * except for the cases where we don't hold i_writecount yet. Then we need to 3081da177e4SLinus Torvalds * use {get,deny}_write_access() - these functions check the sign and refuse 3091da177e4SLinus Torvalds * to do the change if sign is wrong. Exclusion between them is provided by 3101da177e4SLinus Torvalds * the inode->i_lock spinlock. 3111da177e4SLinus Torvalds */ 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds int get_write_access(struct inode * inode) 3141da177e4SLinus Torvalds { 3151da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3161da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) < 0) { 3171da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3181da177e4SLinus Torvalds return -ETXTBSY; 3191da177e4SLinus Torvalds } 3201da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 3211da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3221da177e4SLinus Torvalds 3231da177e4SLinus Torvalds return 0; 3241da177e4SLinus Torvalds } 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds int deny_write_access(struct file * file) 3271da177e4SLinus Torvalds { 3280f7fc9e4SJosef "Jeff" Sipek struct inode *inode = file->f_path.dentry->d_inode; 3291da177e4SLinus Torvalds 3301da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3311da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) > 0) { 3321da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3331da177e4SLinus Torvalds return -ETXTBSY; 3341da177e4SLinus Torvalds } 3351da177e4SLinus Torvalds atomic_dec(&inode->i_writecount); 3361da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3371da177e4SLinus Torvalds 3381da177e4SLinus Torvalds return 0; 3391da177e4SLinus Torvalds } 3401da177e4SLinus Torvalds 3411d957f9bSJan Blunck /** 3425dd784d0SJan Blunck * path_get - get a reference to a path 3435dd784d0SJan Blunck * @path: path to get the reference to 3445dd784d0SJan Blunck * 3455dd784d0SJan Blunck * Given a path increment the reference count to the dentry and the vfsmount. 3465dd784d0SJan Blunck */ 3475dd784d0SJan Blunck void path_get(struct path *path) 3485dd784d0SJan Blunck { 3495dd784d0SJan Blunck mntget(path->mnt); 3505dd784d0SJan Blunck dget(path->dentry); 3515dd784d0SJan Blunck } 3525dd784d0SJan Blunck EXPORT_SYMBOL(path_get); 3535dd784d0SJan Blunck 3545dd784d0SJan Blunck /** 3551d957f9bSJan Blunck * path_put - put a reference to a path 3561d957f9bSJan Blunck * @path: path to put the reference to 3571d957f9bSJan Blunck * 3581d957f9bSJan Blunck * Given a path decrement the reference count to the dentry and the vfsmount. 3591d957f9bSJan Blunck */ 3601d957f9bSJan Blunck void path_put(struct path *path) 3611da177e4SLinus Torvalds { 3621d957f9bSJan Blunck dput(path->dentry); 3631d957f9bSJan Blunck mntput(path->mnt); 3641da177e4SLinus Torvalds } 3651d957f9bSJan Blunck EXPORT_SYMBOL(path_put); 3661da177e4SLinus Torvalds 367834f2a4aSTrond Myklebust /** 368834f2a4aSTrond Myklebust * release_open_intent - free up open intent resources 369834f2a4aSTrond Myklebust * @nd: pointer to nameidata 370834f2a4aSTrond Myklebust */ 371834f2a4aSTrond Myklebust void release_open_intent(struct nameidata *nd) 372834f2a4aSTrond Myklebust { 3730f7fc9e4SJosef "Jeff" Sipek if (nd->intent.open.file->f_path.dentry == NULL) 374834f2a4aSTrond Myklebust put_filp(nd->intent.open.file); 375834f2a4aSTrond Myklebust else 376834f2a4aSTrond Myklebust fput(nd->intent.open.file); 377834f2a4aSTrond Myklebust } 378834f2a4aSTrond Myklebust 379bcdc5e01SIan Kent static inline struct dentry * 380bcdc5e01SIan Kent do_revalidate(struct dentry *dentry, struct nameidata *nd) 381bcdc5e01SIan Kent { 382bcdc5e01SIan Kent int status = dentry->d_op->d_revalidate(dentry, nd); 383bcdc5e01SIan Kent if (unlikely(status <= 0)) { 384bcdc5e01SIan Kent /* 385bcdc5e01SIan Kent * The dentry failed validation. 386bcdc5e01SIan Kent * If d_revalidate returned 0 attempt to invalidate 387bcdc5e01SIan Kent * the dentry otherwise d_revalidate is asking us 388bcdc5e01SIan Kent * to return a fail status. 389bcdc5e01SIan Kent */ 390bcdc5e01SIan Kent if (!status) { 391bcdc5e01SIan Kent if (!d_invalidate(dentry)) { 392bcdc5e01SIan Kent dput(dentry); 393bcdc5e01SIan Kent dentry = NULL; 394bcdc5e01SIan Kent } 395bcdc5e01SIan Kent } else { 396bcdc5e01SIan Kent dput(dentry); 397bcdc5e01SIan Kent dentry = ERR_PTR(status); 398bcdc5e01SIan Kent } 399bcdc5e01SIan Kent } 400bcdc5e01SIan Kent return dentry; 401bcdc5e01SIan Kent } 402bcdc5e01SIan Kent 4031da177e4SLinus Torvalds /* 4041da177e4SLinus Torvalds * Internal lookup() using the new generic dcache. 4051da177e4SLinus Torvalds * SMP-safe 4061da177e4SLinus Torvalds */ 4071da177e4SLinus Torvalds static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4081da177e4SLinus Torvalds { 4091da177e4SLinus Torvalds struct dentry * dentry = __d_lookup(parent, name); 4101da177e4SLinus Torvalds 4111da177e4SLinus Torvalds /* lockess __d_lookup may fail due to concurrent d_move() 4121da177e4SLinus Torvalds * in some unrelated directory, so try with d_lookup 4131da177e4SLinus Torvalds */ 4141da177e4SLinus Torvalds if (!dentry) 4151da177e4SLinus Torvalds dentry = d_lookup(parent, name); 4161da177e4SLinus Torvalds 417bcdc5e01SIan Kent if (dentry && dentry->d_op && dentry->d_op->d_revalidate) 418bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 419bcdc5e01SIan Kent 4201da177e4SLinus Torvalds return dentry; 4211da177e4SLinus Torvalds } 4221da177e4SLinus Torvalds 4231da177e4SLinus Torvalds /* 4241da177e4SLinus Torvalds * Short-cut version of permission(), for calling by 4251da177e4SLinus Torvalds * path_walk(), when dcache lock is held. Combines parts 4261da177e4SLinus Torvalds * of permission() and generic_permission(), and tests ONLY for 4271da177e4SLinus Torvalds * MAY_EXEC permission. 4281da177e4SLinus Torvalds * 4291da177e4SLinus Torvalds * If appropriate, check DAC only. If not appropriate, or 4301da177e4SLinus Torvalds * short-cut DAC fails, then call permission() to do more 4311da177e4SLinus Torvalds * complete permission check. 4321da177e4SLinus Torvalds */ 433672b16b2SAl Viro static int exec_permission_lite(struct inode *inode) 4341da177e4SLinus Torvalds { 4351da177e4SLinus Torvalds umode_t mode = inode->i_mode; 4361da177e4SLinus Torvalds 437acfa4380SAl Viro if (inode->i_op->permission) 4381da177e4SLinus Torvalds return -EAGAIN; 4391da177e4SLinus Torvalds 440da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 4411da177e4SLinus Torvalds mode >>= 6; 4421da177e4SLinus Torvalds else if (in_group_p(inode->i_gid)) 4431da177e4SLinus Torvalds mode >>= 3; 4441da177e4SLinus Torvalds 4451da177e4SLinus Torvalds if (mode & MAY_EXEC) 4461da177e4SLinus Torvalds goto ok; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE)) 4491da177e4SLinus Torvalds goto ok; 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE)) 4521da177e4SLinus Torvalds goto ok; 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH)) 4551da177e4SLinus Torvalds goto ok; 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds return -EACCES; 4581da177e4SLinus Torvalds ok: 459b77b0646SAl Viro return security_inode_permission(inode, MAY_EXEC); 4601da177e4SLinus Torvalds } 4611da177e4SLinus Torvalds 4621da177e4SLinus Torvalds /* 4631da177e4SLinus Torvalds * This is called when everything else fails, and we actually have 4641da177e4SLinus Torvalds * to go to the low-level filesystem to find out what we should do.. 4651da177e4SLinus Torvalds * 4661da177e4SLinus Torvalds * We get the directory semaphore, and after getting that we also 4671da177e4SLinus Torvalds * make sure that nobody added the entry to the dcache in the meantime.. 4681da177e4SLinus Torvalds * SMP-safe 4691da177e4SLinus Torvalds */ 4701da177e4SLinus Torvalds static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4711da177e4SLinus Torvalds { 4721da177e4SLinus Torvalds struct dentry * result; 4731da177e4SLinus Torvalds struct inode *dir = parent->d_inode; 4741da177e4SLinus Torvalds 4751b1dcc1bSJes Sorensen mutex_lock(&dir->i_mutex); 4761da177e4SLinus Torvalds /* 4771da177e4SLinus Torvalds * First re-do the cached lookup just in case it was created 4781da177e4SLinus Torvalds * while we waited for the directory semaphore.. 4791da177e4SLinus Torvalds * 4801da177e4SLinus Torvalds * FIXME! This could use version numbering or similar to 4811da177e4SLinus Torvalds * avoid unnecessary cache lookups. 4821da177e4SLinus Torvalds * 4831da177e4SLinus Torvalds * The "dcache_lock" is purely to protect the RCU list walker 4841da177e4SLinus Torvalds * from concurrent renames at this point (we mustn't get false 4851da177e4SLinus Torvalds * negatives from the RCU list walk here, unlike the optimistic 4861da177e4SLinus Torvalds * fast walk). 4871da177e4SLinus Torvalds * 4881da177e4SLinus Torvalds * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup 4891da177e4SLinus Torvalds */ 4901da177e4SLinus Torvalds result = d_lookup(parent, name); 4911da177e4SLinus Torvalds if (!result) { 492d70b67c8SMiklos Szeredi struct dentry *dentry; 493d70b67c8SMiklos Szeredi 494d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 495d70b67c8SMiklos Szeredi result = ERR_PTR(-ENOENT); 496d70b67c8SMiklos Szeredi if (IS_DEADDIR(dir)) 497d70b67c8SMiklos Szeredi goto out_unlock; 498d70b67c8SMiklos Szeredi 499d70b67c8SMiklos Szeredi dentry = d_alloc(parent, name); 5001da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 5011da177e4SLinus Torvalds if (dentry) { 5021da177e4SLinus Torvalds result = dir->i_op->lookup(dir, dentry, nd); 5031da177e4SLinus Torvalds if (result) 5041da177e4SLinus Torvalds dput(dentry); 5051da177e4SLinus Torvalds else 5061da177e4SLinus Torvalds result = dentry; 5071da177e4SLinus Torvalds } 508d70b67c8SMiklos Szeredi out_unlock: 5091b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5101da177e4SLinus Torvalds return result; 5111da177e4SLinus Torvalds } 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds /* 5141da177e4SLinus Torvalds * Uhhuh! Nasty case: the cache was re-populated while 5151da177e4SLinus Torvalds * we waited on the semaphore. Need to revalidate. 5161da177e4SLinus Torvalds */ 5171b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5181da177e4SLinus Torvalds if (result->d_op && result->d_op->d_revalidate) { 519bcdc5e01SIan Kent result = do_revalidate(result, nd); 520bcdc5e01SIan Kent if (!result) 5211da177e4SLinus Torvalds result = ERR_PTR(-ENOENT); 5221da177e4SLinus Torvalds } 5231da177e4SLinus Torvalds return result; 5241da177e4SLinus Torvalds } 5251da177e4SLinus Torvalds 526a02f76c3SAl Viro /* 527a02f76c3SAl Viro * Wrapper to retry pathname resolution whenever the underlying 528a02f76c3SAl Viro * file system returns an ESTALE. 529a02f76c3SAl Viro * 530a02f76c3SAl Viro * Retry the whole path once, forcing real lookup requests 531a02f76c3SAl Viro * instead of relying on the dcache. 532a02f76c3SAl Viro */ 533a02f76c3SAl Viro static __always_inline int link_path_walk(const char *name, struct nameidata *nd) 534a02f76c3SAl Viro { 535a02f76c3SAl Viro struct path save = nd->path; 536a02f76c3SAl Viro int result; 537a02f76c3SAl Viro 538a02f76c3SAl Viro /* make sure the stuff we saved doesn't go away */ 539c8e7f449SJan Blunck path_get(&save); 540a02f76c3SAl Viro 541a02f76c3SAl Viro result = __link_path_walk(name, nd); 542a02f76c3SAl Viro if (result == -ESTALE) { 543a02f76c3SAl Viro /* nd->path had been dropped */ 544a02f76c3SAl Viro nd->path = save; 545c8e7f449SJan Blunck path_get(&nd->path); 546a02f76c3SAl Viro nd->flags |= LOOKUP_REVAL; 547a02f76c3SAl Viro result = __link_path_walk(name, nd); 548a02f76c3SAl Viro } 549a02f76c3SAl Viro 550a02f76c3SAl Viro path_put(&save); 551a02f76c3SAl Viro 552a02f76c3SAl Viro return result; 553a02f76c3SAl Viro } 554a02f76c3SAl Viro 555f1662356SArjan van de Ven static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) 5561da177e4SLinus Torvalds { 5571da177e4SLinus Torvalds int res = 0; 5581da177e4SLinus Torvalds char *name; 5591da177e4SLinus Torvalds if (IS_ERR(link)) 5601da177e4SLinus Torvalds goto fail; 5611da177e4SLinus Torvalds 5621da177e4SLinus Torvalds if (*link == '/') { 563b4091d5fSChristoph Hellwig struct fs_struct *fs = current->fs; 564b4091d5fSChristoph Hellwig 5651d957f9bSJan Blunck path_put(&nd->path); 566b4091d5fSChristoph Hellwig 567b4091d5fSChristoph Hellwig read_lock(&fs->lock); 568b4091d5fSChristoph Hellwig nd->path = fs->root; 569b4091d5fSChristoph Hellwig path_get(&fs->root); 570b4091d5fSChristoph Hellwig read_unlock(&fs->lock); 5711da177e4SLinus Torvalds } 572b4091d5fSChristoph Hellwig 5731da177e4SLinus Torvalds res = link_path_walk(link, nd); 5741da177e4SLinus Torvalds if (nd->depth || res || nd->last_type!=LAST_NORM) 5751da177e4SLinus Torvalds return res; 5761da177e4SLinus Torvalds /* 5771da177e4SLinus Torvalds * If it is an iterative symlinks resolution in open_namei() we 5781da177e4SLinus Torvalds * have to copy the last component. And all that crap because of 5791da177e4SLinus Torvalds * bloody create() on broken symlinks. Furrfu... 5801da177e4SLinus Torvalds */ 5811da177e4SLinus Torvalds name = __getname(); 5821da177e4SLinus Torvalds if (unlikely(!name)) { 5831d957f9bSJan Blunck path_put(&nd->path); 5841da177e4SLinus Torvalds return -ENOMEM; 5851da177e4SLinus Torvalds } 5861da177e4SLinus Torvalds strcpy(name, nd->last.name); 5871da177e4SLinus Torvalds nd->last.name = name; 5881da177e4SLinus Torvalds return 0; 5891da177e4SLinus Torvalds fail: 5901d957f9bSJan Blunck path_put(&nd->path); 5911da177e4SLinus Torvalds return PTR_ERR(link); 5921da177e4SLinus Torvalds } 5931da177e4SLinus Torvalds 5941d957f9bSJan Blunck static void path_put_conditional(struct path *path, struct nameidata *nd) 595051d3812SIan Kent { 596051d3812SIan Kent dput(path->dentry); 5974ac91378SJan Blunck if (path->mnt != nd->path.mnt) 598051d3812SIan Kent mntput(path->mnt); 599051d3812SIan Kent } 600051d3812SIan Kent 601051d3812SIan Kent static inline void path_to_nameidata(struct path *path, struct nameidata *nd) 602051d3812SIan Kent { 6034ac91378SJan Blunck dput(nd->path.dentry); 6044ac91378SJan Blunck if (nd->path.mnt != path->mnt) 6054ac91378SJan Blunck mntput(nd->path.mnt); 6064ac91378SJan Blunck nd->path.mnt = path->mnt; 6074ac91378SJan Blunck nd->path.dentry = path->dentry; 608051d3812SIan Kent } 609051d3812SIan Kent 610f1662356SArjan van de Ven static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) 6111da177e4SLinus Torvalds { 6121da177e4SLinus Torvalds int error; 613cc314eefSLinus Torvalds void *cookie; 614cd4e91d3SAl Viro struct dentry *dentry = path->dentry; 6151da177e4SLinus Torvalds 616d671a1cbSAl Viro touch_atime(path->mnt, dentry); 6171da177e4SLinus Torvalds nd_set_link(nd, NULL); 618cd4e91d3SAl Viro 6194ac91378SJan Blunck if (path->mnt != nd->path.mnt) { 620051d3812SIan Kent path_to_nameidata(path, nd); 621051d3812SIan Kent dget(dentry); 622051d3812SIan Kent } 623cd4e91d3SAl Viro mntget(path->mnt); 624cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, nd); 625cc314eefSLinus Torvalds error = PTR_ERR(cookie); 626cc314eefSLinus Torvalds if (!IS_ERR(cookie)) { 6271da177e4SLinus Torvalds char *s = nd_get_link(nd); 628cc314eefSLinus Torvalds error = 0; 6291da177e4SLinus Torvalds if (s) 6301da177e4SLinus Torvalds error = __vfs_follow_link(nd, s); 6311da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 632cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, nd, cookie); 6331da177e4SLinus Torvalds } 63409da5916SJan Blunck path_put(path); 6351da177e4SLinus Torvalds 6361da177e4SLinus Torvalds return error; 6371da177e4SLinus Torvalds } 6381da177e4SLinus Torvalds 6391da177e4SLinus Torvalds /* 6401da177e4SLinus Torvalds * This limits recursive symlink follows to 8, while 6411da177e4SLinus Torvalds * limiting consecutive symlinks to 40. 6421da177e4SLinus Torvalds * 6431da177e4SLinus Torvalds * Without that kind of total limit, nasty chains of consecutive 6441da177e4SLinus Torvalds * symlinks can cause almost arbitrarily long lookups. 6451da177e4SLinus Torvalds */ 64690ebe565SAl Viro static inline int do_follow_link(struct path *path, struct nameidata *nd) 6471da177e4SLinus Torvalds { 6481da177e4SLinus Torvalds int err = -ELOOP; 6491da177e4SLinus Torvalds if (current->link_count >= MAX_NESTED_LINKS) 6501da177e4SLinus Torvalds goto loop; 6511da177e4SLinus Torvalds if (current->total_link_count >= 40) 6521da177e4SLinus Torvalds goto loop; 6531da177e4SLinus Torvalds BUG_ON(nd->depth >= MAX_NESTED_LINKS); 6541da177e4SLinus Torvalds cond_resched(); 65590ebe565SAl Viro err = security_inode_follow_link(path->dentry, nd); 6561da177e4SLinus Torvalds if (err) 6571da177e4SLinus Torvalds goto loop; 6581da177e4SLinus Torvalds current->link_count++; 6591da177e4SLinus Torvalds current->total_link_count++; 6601da177e4SLinus Torvalds nd->depth++; 661cd4e91d3SAl Viro err = __do_follow_link(path, nd); 6621da177e4SLinus Torvalds current->link_count--; 6631da177e4SLinus Torvalds nd->depth--; 6641da177e4SLinus Torvalds return err; 6651da177e4SLinus Torvalds loop: 6661d957f9bSJan Blunck path_put_conditional(path, nd); 6671d957f9bSJan Blunck path_put(&nd->path); 6681da177e4SLinus Torvalds return err; 6691da177e4SLinus Torvalds } 6701da177e4SLinus Torvalds 6711da177e4SLinus Torvalds int follow_up(struct vfsmount **mnt, struct dentry **dentry) 6721da177e4SLinus Torvalds { 6731da177e4SLinus Torvalds struct vfsmount *parent; 6741da177e4SLinus Torvalds struct dentry *mountpoint; 6751da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 6761da177e4SLinus Torvalds parent=(*mnt)->mnt_parent; 6771da177e4SLinus Torvalds if (parent == *mnt) { 6781da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6791da177e4SLinus Torvalds return 0; 6801da177e4SLinus Torvalds } 6811da177e4SLinus Torvalds mntget(parent); 6821da177e4SLinus Torvalds mountpoint=dget((*mnt)->mnt_mountpoint); 6831da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6841da177e4SLinus Torvalds dput(*dentry); 6851da177e4SLinus Torvalds *dentry = mountpoint; 6861da177e4SLinus Torvalds mntput(*mnt); 6871da177e4SLinus Torvalds *mnt = parent; 6881da177e4SLinus Torvalds return 1; 6891da177e4SLinus Torvalds } 6901da177e4SLinus Torvalds 6911da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 6921da177e4SLinus Torvalds * namespace.c 6931da177e4SLinus Torvalds */ 694463ffb2eSAl Viro static int __follow_mount(struct path *path) 695463ffb2eSAl Viro { 696463ffb2eSAl Viro int res = 0; 697463ffb2eSAl Viro while (d_mountpoint(path->dentry)) { 698463ffb2eSAl Viro struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry); 699463ffb2eSAl Viro if (!mounted) 700463ffb2eSAl Viro break; 701463ffb2eSAl Viro dput(path->dentry); 702463ffb2eSAl Viro if (res) 703463ffb2eSAl Viro mntput(path->mnt); 704463ffb2eSAl Viro path->mnt = mounted; 705463ffb2eSAl Viro path->dentry = dget(mounted->mnt_root); 706463ffb2eSAl Viro res = 1; 707463ffb2eSAl Viro } 708463ffb2eSAl Viro return res; 709463ffb2eSAl Viro } 710463ffb2eSAl Viro 71158c465ebSAl Viro static void follow_mount(struct vfsmount **mnt, struct dentry **dentry) 7121da177e4SLinus Torvalds { 7131da177e4SLinus Torvalds while (d_mountpoint(*dentry)) { 7141da177e4SLinus Torvalds struct vfsmount *mounted = lookup_mnt(*mnt, *dentry); 7151da177e4SLinus Torvalds if (!mounted) 7161da177e4SLinus Torvalds break; 71758c465ebSAl Viro dput(*dentry); 7181da177e4SLinus Torvalds mntput(*mnt); 7191da177e4SLinus Torvalds *mnt = mounted; 7201da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7211da177e4SLinus Torvalds } 7221da177e4SLinus Torvalds } 7231da177e4SLinus Torvalds 7241da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 7251da177e4SLinus Torvalds * namespace.c 7261da177e4SLinus Torvalds */ 727e13b210fSAl Viro int follow_down(struct vfsmount **mnt, struct dentry **dentry) 7281da177e4SLinus Torvalds { 7291da177e4SLinus Torvalds struct vfsmount *mounted; 7301da177e4SLinus Torvalds 7311da177e4SLinus Torvalds mounted = lookup_mnt(*mnt, *dentry); 7321da177e4SLinus Torvalds if (mounted) { 733e13b210fSAl Viro dput(*dentry); 7341da177e4SLinus Torvalds mntput(*mnt); 7351da177e4SLinus Torvalds *mnt = mounted; 7361da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7371da177e4SLinus Torvalds return 1; 7381da177e4SLinus Torvalds } 7391da177e4SLinus Torvalds return 0; 7401da177e4SLinus Torvalds } 7411da177e4SLinus Torvalds 742f1662356SArjan van de Ven static __always_inline void follow_dotdot(struct nameidata *nd) 7431da177e4SLinus Torvalds { 744e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 745e518ddb7SAndreas Mohr 7461da177e4SLinus Torvalds while(1) { 7471da177e4SLinus Torvalds struct vfsmount *parent; 7484ac91378SJan Blunck struct dentry *old = nd->path.dentry; 7491da177e4SLinus Torvalds 750e518ddb7SAndreas Mohr read_lock(&fs->lock); 7516ac08c39SJan Blunck if (nd->path.dentry == fs->root.dentry && 7526ac08c39SJan Blunck nd->path.mnt == fs->root.mnt) { 753e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7541da177e4SLinus Torvalds break; 7551da177e4SLinus Torvalds } 756e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7571da177e4SLinus Torvalds spin_lock(&dcache_lock); 7584ac91378SJan Blunck if (nd->path.dentry != nd->path.mnt->mnt_root) { 7594ac91378SJan Blunck nd->path.dentry = dget(nd->path.dentry->d_parent); 7601da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7611da177e4SLinus Torvalds dput(old); 7621da177e4SLinus Torvalds break; 7631da177e4SLinus Torvalds } 7641da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7651da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 7664ac91378SJan Blunck parent = nd->path.mnt->mnt_parent; 7674ac91378SJan Blunck if (parent == nd->path.mnt) { 7681da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7691da177e4SLinus Torvalds break; 7701da177e4SLinus Torvalds } 7711da177e4SLinus Torvalds mntget(parent); 7724ac91378SJan Blunck nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); 7731da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7741da177e4SLinus Torvalds dput(old); 7754ac91378SJan Blunck mntput(nd->path.mnt); 7764ac91378SJan Blunck nd->path.mnt = parent; 7771da177e4SLinus Torvalds } 7784ac91378SJan Blunck follow_mount(&nd->path.mnt, &nd->path.dentry); 7791da177e4SLinus Torvalds } 7801da177e4SLinus Torvalds 7811da177e4SLinus Torvalds /* 7821da177e4SLinus Torvalds * It's more convoluted than I'd like it to be, but... it's still fairly 7831da177e4SLinus Torvalds * small and for now I'd prefer to have fast path as straight as possible. 7841da177e4SLinus Torvalds * It _is_ time-critical. 7851da177e4SLinus Torvalds */ 7861da177e4SLinus Torvalds static int do_lookup(struct nameidata *nd, struct qstr *name, 7871da177e4SLinus Torvalds struct path *path) 7881da177e4SLinus Torvalds { 7894ac91378SJan Blunck struct vfsmount *mnt = nd->path.mnt; 7904ac91378SJan Blunck struct dentry *dentry = __d_lookup(nd->path.dentry, name); 7911da177e4SLinus Torvalds 7921da177e4SLinus Torvalds if (!dentry) 7931da177e4SLinus Torvalds goto need_lookup; 7941da177e4SLinus Torvalds if (dentry->d_op && dentry->d_op->d_revalidate) 7951da177e4SLinus Torvalds goto need_revalidate; 7961da177e4SLinus Torvalds done: 7971da177e4SLinus Torvalds path->mnt = mnt; 7981da177e4SLinus Torvalds path->dentry = dentry; 799634ee701SAl Viro __follow_mount(path); 8001da177e4SLinus Torvalds return 0; 8011da177e4SLinus Torvalds 8021da177e4SLinus Torvalds need_lookup: 8034ac91378SJan Blunck dentry = real_lookup(nd->path.dentry, name, nd); 8041da177e4SLinus Torvalds if (IS_ERR(dentry)) 8051da177e4SLinus Torvalds goto fail; 8061da177e4SLinus Torvalds goto done; 8071da177e4SLinus Torvalds 8081da177e4SLinus Torvalds need_revalidate: 809bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 810bcdc5e01SIan Kent if (!dentry) 8111da177e4SLinus Torvalds goto need_lookup; 812bcdc5e01SIan Kent if (IS_ERR(dentry)) 813bcdc5e01SIan Kent goto fail; 814bcdc5e01SIan Kent goto done; 8151da177e4SLinus Torvalds 8161da177e4SLinus Torvalds fail: 8171da177e4SLinus Torvalds return PTR_ERR(dentry); 8181da177e4SLinus Torvalds } 8191da177e4SLinus Torvalds 8201da177e4SLinus Torvalds /* 8211da177e4SLinus Torvalds * Name resolution. 822ea3834d9SPrasanna Meda * This is the basic name resolution function, turning a pathname into 823ea3834d9SPrasanna Meda * the final dentry. We expect 'base' to be positive and a directory. 8241da177e4SLinus Torvalds * 825ea3834d9SPrasanna Meda * Returns 0 and nd will have valid dentry and mnt on success. 826ea3834d9SPrasanna Meda * Returns error and drops reference to input namei data on failure. 8271da177e4SLinus Torvalds */ 828fc9b52cdSHarvey Harrison static int __link_path_walk(const char *name, struct nameidata *nd) 8291da177e4SLinus Torvalds { 8301da177e4SLinus Torvalds struct path next; 8311da177e4SLinus Torvalds struct inode *inode; 8321da177e4SLinus Torvalds int err; 8331da177e4SLinus Torvalds unsigned int lookup_flags = nd->flags; 8341da177e4SLinus Torvalds 8351da177e4SLinus Torvalds while (*name=='/') 8361da177e4SLinus Torvalds name++; 8371da177e4SLinus Torvalds if (!*name) 8381da177e4SLinus Torvalds goto return_reval; 8391da177e4SLinus Torvalds 8404ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8411da177e4SLinus Torvalds if (nd->depth) 842f55eab82STrond Myklebust lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); 8431da177e4SLinus Torvalds 8441da177e4SLinus Torvalds /* At this point we know we have a real path component. */ 8451da177e4SLinus Torvalds for(;;) { 8461da177e4SLinus Torvalds unsigned long hash; 8471da177e4SLinus Torvalds struct qstr this; 8481da177e4SLinus Torvalds unsigned int c; 8491da177e4SLinus Torvalds 850cdce5d6bSTrond Myklebust nd->flags |= LOOKUP_CONTINUE; 851672b16b2SAl Viro err = exec_permission_lite(inode); 852e4543eddSChristoph Hellwig if (err == -EAGAIN) 853cb23beb5SChristoph Hellwig err = inode_permission(nd->path.dentry->d_inode, 854cb23beb5SChristoph Hellwig MAY_EXEC); 8556146f0d5SMimi Zohar if (!err) 8566146f0d5SMimi Zohar err = ima_path_check(&nd->path, MAY_EXEC); 8571da177e4SLinus Torvalds if (err) 8581da177e4SLinus Torvalds break; 8591da177e4SLinus Torvalds 8601da177e4SLinus Torvalds this.name = name; 8611da177e4SLinus Torvalds c = *(const unsigned char *)name; 8621da177e4SLinus Torvalds 8631da177e4SLinus Torvalds hash = init_name_hash(); 8641da177e4SLinus Torvalds do { 8651da177e4SLinus Torvalds name++; 8661da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 8671da177e4SLinus Torvalds c = *(const unsigned char *)name; 8681da177e4SLinus Torvalds } while (c && (c != '/')); 8691da177e4SLinus Torvalds this.len = name - (const char *) this.name; 8701da177e4SLinus Torvalds this.hash = end_name_hash(hash); 8711da177e4SLinus Torvalds 8721da177e4SLinus Torvalds /* remove trailing slashes? */ 8731da177e4SLinus Torvalds if (!c) 8741da177e4SLinus Torvalds goto last_component; 8751da177e4SLinus Torvalds while (*++name == '/'); 8761da177e4SLinus Torvalds if (!*name) 8771da177e4SLinus Torvalds goto last_with_slashes; 8781da177e4SLinus Torvalds 8791da177e4SLinus Torvalds /* 8801da177e4SLinus Torvalds * "." and ".." are special - ".." especially so because it has 8811da177e4SLinus Torvalds * to be able to know about the current root directory and 8821da177e4SLinus Torvalds * parent relationships. 8831da177e4SLinus Torvalds */ 8841da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 8851da177e4SLinus Torvalds default: 8861da177e4SLinus Torvalds break; 8871da177e4SLinus Torvalds case 2: 8881da177e4SLinus Torvalds if (this.name[1] != '.') 8891da177e4SLinus Torvalds break; 89058c465ebSAl Viro follow_dotdot(nd); 8914ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8921da177e4SLinus Torvalds /* fallthrough */ 8931da177e4SLinus Torvalds case 1: 8941da177e4SLinus Torvalds continue; 8951da177e4SLinus Torvalds } 8961da177e4SLinus Torvalds /* 8971da177e4SLinus Torvalds * See if the low-level filesystem might want 8981da177e4SLinus Torvalds * to use its own hash.. 8991da177e4SLinus Torvalds */ 9004ac91378SJan Blunck if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 9014ac91378SJan Blunck err = nd->path.dentry->d_op->d_hash(nd->path.dentry, 9024ac91378SJan Blunck &this); 9031da177e4SLinus Torvalds if (err < 0) 9041da177e4SLinus Torvalds break; 9051da177e4SLinus Torvalds } 9061da177e4SLinus Torvalds /* This does the actual lookups.. */ 9071da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9081da177e4SLinus Torvalds if (err) 9091da177e4SLinus Torvalds break; 9101da177e4SLinus Torvalds 9111da177e4SLinus Torvalds err = -ENOENT; 9121da177e4SLinus Torvalds inode = next.dentry->d_inode; 9131da177e4SLinus Torvalds if (!inode) 9141da177e4SLinus Torvalds goto out_dput; 9151da177e4SLinus Torvalds 9161da177e4SLinus Torvalds if (inode->i_op->follow_link) { 91790ebe565SAl Viro err = do_follow_link(&next, nd); 9181da177e4SLinus Torvalds if (err) 9191da177e4SLinus Torvalds goto return_err; 9201da177e4SLinus Torvalds err = -ENOENT; 9214ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9221da177e4SLinus Torvalds if (!inode) 9231da177e4SLinus Torvalds break; 92409dd17d3SMiklos Szeredi } else 92509dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9261da177e4SLinus Torvalds err = -ENOTDIR; 9271da177e4SLinus Torvalds if (!inode->i_op->lookup) 9281da177e4SLinus Torvalds break; 9291da177e4SLinus Torvalds continue; 9301da177e4SLinus Torvalds /* here ends the main loop */ 9311da177e4SLinus Torvalds 9321da177e4SLinus Torvalds last_with_slashes: 9331da177e4SLinus Torvalds lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 9341da177e4SLinus Torvalds last_component: 935f55eab82STrond Myklebust /* Clear LOOKUP_CONTINUE iff it was previously unset */ 936f55eab82STrond Myklebust nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; 9371da177e4SLinus Torvalds if (lookup_flags & LOOKUP_PARENT) 9381da177e4SLinus Torvalds goto lookup_parent; 9391da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 9401da177e4SLinus Torvalds default: 9411da177e4SLinus Torvalds break; 9421da177e4SLinus Torvalds case 2: 9431da177e4SLinus Torvalds if (this.name[1] != '.') 9441da177e4SLinus Torvalds break; 94558c465ebSAl Viro follow_dotdot(nd); 9464ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9471da177e4SLinus Torvalds /* fallthrough */ 9481da177e4SLinus Torvalds case 1: 9491da177e4SLinus Torvalds goto return_reval; 9501da177e4SLinus Torvalds } 9514ac91378SJan Blunck if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 9524ac91378SJan Blunck err = nd->path.dentry->d_op->d_hash(nd->path.dentry, 9534ac91378SJan Blunck &this); 9541da177e4SLinus Torvalds if (err < 0) 9551da177e4SLinus Torvalds break; 9561da177e4SLinus Torvalds } 9571da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9581da177e4SLinus Torvalds if (err) 9591da177e4SLinus Torvalds break; 9601da177e4SLinus Torvalds inode = next.dentry->d_inode; 9611da177e4SLinus Torvalds if ((lookup_flags & LOOKUP_FOLLOW) 962acfa4380SAl Viro && inode && inode->i_op->follow_link) { 96390ebe565SAl Viro err = do_follow_link(&next, nd); 9641da177e4SLinus Torvalds if (err) 9651da177e4SLinus Torvalds goto return_err; 9664ac91378SJan Blunck inode = nd->path.dentry->d_inode; 96709dd17d3SMiklos Szeredi } else 96809dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9691da177e4SLinus Torvalds err = -ENOENT; 9701da177e4SLinus Torvalds if (!inode) 9711da177e4SLinus Torvalds break; 9721da177e4SLinus Torvalds if (lookup_flags & LOOKUP_DIRECTORY) { 9731da177e4SLinus Torvalds err = -ENOTDIR; 974acfa4380SAl Viro if (!inode->i_op->lookup) 9751da177e4SLinus Torvalds break; 9761da177e4SLinus Torvalds } 9771da177e4SLinus Torvalds goto return_base; 9781da177e4SLinus Torvalds lookup_parent: 9791da177e4SLinus Torvalds nd->last = this; 9801da177e4SLinus Torvalds nd->last_type = LAST_NORM; 9811da177e4SLinus Torvalds if (this.name[0] != '.') 9821da177e4SLinus Torvalds goto return_base; 9831da177e4SLinus Torvalds if (this.len == 1) 9841da177e4SLinus Torvalds nd->last_type = LAST_DOT; 9851da177e4SLinus Torvalds else if (this.len == 2 && this.name[1] == '.') 9861da177e4SLinus Torvalds nd->last_type = LAST_DOTDOT; 9871da177e4SLinus Torvalds else 9881da177e4SLinus Torvalds goto return_base; 9891da177e4SLinus Torvalds return_reval: 9901da177e4SLinus Torvalds /* 9911da177e4SLinus Torvalds * We bypassed the ordinary revalidation routines. 9921da177e4SLinus Torvalds * We may need to check the cached dentry for staleness. 9931da177e4SLinus Torvalds */ 9944ac91378SJan Blunck if (nd->path.dentry && nd->path.dentry->d_sb && 9954ac91378SJan Blunck (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { 9961da177e4SLinus Torvalds err = -ESTALE; 9971da177e4SLinus Torvalds /* Note: we do not d_invalidate() */ 9984ac91378SJan Blunck if (!nd->path.dentry->d_op->d_revalidate( 9994ac91378SJan Blunck nd->path.dentry, nd)) 10001da177e4SLinus Torvalds break; 10011da177e4SLinus Torvalds } 10021da177e4SLinus Torvalds return_base: 10031da177e4SLinus Torvalds return 0; 10041da177e4SLinus Torvalds out_dput: 10051d957f9bSJan Blunck path_put_conditional(&next, nd); 10061da177e4SLinus Torvalds break; 10071da177e4SLinus Torvalds } 10081d957f9bSJan Blunck path_put(&nd->path); 10091da177e4SLinus Torvalds return_err: 10101da177e4SLinus Torvalds return err; 10111da177e4SLinus Torvalds } 10121da177e4SLinus Torvalds 1013fc9b52cdSHarvey Harrison static int path_walk(const char *name, struct nameidata *nd) 10141da177e4SLinus Torvalds { 10151da177e4SLinus Torvalds current->total_link_count = 0; 10161da177e4SLinus Torvalds return link_path_walk(name, nd); 10171da177e4SLinus Torvalds } 10181da177e4SLinus Torvalds 1019ea3834d9SPrasanna Meda /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ 1020fc9b52cdSHarvey Harrison static int do_path_lookup(int dfd, const char *name, 10215590ff0dSUlrich Drepper unsigned int flags, struct nameidata *nd) 10221da177e4SLinus Torvalds { 1023ea3834d9SPrasanna Meda int retval = 0; 1024170aa3d0SUlrich Drepper int fput_needed; 1025170aa3d0SUlrich Drepper struct file *file; 1026e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 10271da177e4SLinus Torvalds 10281da177e4SLinus Torvalds nd->last_type = LAST_ROOT; /* if there are only slashes... */ 10291da177e4SLinus Torvalds nd->flags = flags; 10301da177e4SLinus Torvalds nd->depth = 0; 10311da177e4SLinus Torvalds 10321da177e4SLinus Torvalds if (*name=='/') { 1033e518ddb7SAndreas Mohr read_lock(&fs->lock); 10346ac08c39SJan Blunck nd->path = fs->root; 10356ac08c39SJan Blunck path_get(&fs->root); 1036e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10375590ff0dSUlrich Drepper } else if (dfd == AT_FDCWD) { 1038e518ddb7SAndreas Mohr read_lock(&fs->lock); 10396ac08c39SJan Blunck nd->path = fs->pwd; 10406ac08c39SJan Blunck path_get(&fs->pwd); 1041e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10425590ff0dSUlrich Drepper } else { 10435590ff0dSUlrich Drepper struct dentry *dentry; 10445590ff0dSUlrich Drepper 10455590ff0dSUlrich Drepper file = fget_light(dfd, &fput_needed); 10465590ff0dSUlrich Drepper retval = -EBADF; 1047170aa3d0SUlrich Drepper if (!file) 10486d09bb62STrond Myklebust goto out_fail; 10495590ff0dSUlrich Drepper 10500f7fc9e4SJosef "Jeff" Sipek dentry = file->f_path.dentry; 10515590ff0dSUlrich Drepper 10525590ff0dSUlrich Drepper retval = -ENOTDIR; 1053170aa3d0SUlrich Drepper if (!S_ISDIR(dentry->d_inode->i_mode)) 10546d09bb62STrond Myklebust goto fput_fail; 10555590ff0dSUlrich Drepper 10565590ff0dSUlrich Drepper retval = file_permission(file, MAY_EXEC); 1057170aa3d0SUlrich Drepper if (retval) 10586d09bb62STrond Myklebust goto fput_fail; 10595590ff0dSUlrich Drepper 10605dd784d0SJan Blunck nd->path = file->f_path; 10615dd784d0SJan Blunck path_get(&file->f_path); 10625590ff0dSUlrich Drepper 10635590ff0dSUlrich Drepper fput_light(file, fput_needed); 10641da177e4SLinus Torvalds } 10652dfdd266SJosef 'Jeff' Sipek 10662dfdd266SJosef 'Jeff' Sipek retval = path_walk(name, nd); 10674ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 10684ac91378SJan Blunck nd->path.dentry->d_inode)) 10694ac91378SJan Blunck audit_inode(name, nd->path.dentry); 10706d09bb62STrond Myklebust out_fail: 1071170aa3d0SUlrich Drepper return retval; 1072170aa3d0SUlrich Drepper 10736d09bb62STrond Myklebust fput_fail: 1074170aa3d0SUlrich Drepper fput_light(file, fput_needed); 10756d09bb62STrond Myklebust goto out_fail; 10761da177e4SLinus Torvalds } 10771da177e4SLinus Torvalds 1078fc9b52cdSHarvey Harrison int path_lookup(const char *name, unsigned int flags, 10795590ff0dSUlrich Drepper struct nameidata *nd) 10805590ff0dSUlrich Drepper { 10815590ff0dSUlrich Drepper return do_path_lookup(AT_FDCWD, name, flags, nd); 10825590ff0dSUlrich Drepper } 10835590ff0dSUlrich Drepper 1084d1811465SAl Viro int kern_path(const char *name, unsigned int flags, struct path *path) 1085d1811465SAl Viro { 1086d1811465SAl Viro struct nameidata nd; 1087d1811465SAl Viro int res = do_path_lookup(AT_FDCWD, name, flags, &nd); 1088d1811465SAl Viro if (!res) 1089d1811465SAl Viro *path = nd.path; 1090d1811465SAl Viro return res; 1091d1811465SAl Viro } 1092d1811465SAl Viro 109316f18200SJosef 'Jeff' Sipek /** 109416f18200SJosef 'Jeff' Sipek * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair 109516f18200SJosef 'Jeff' Sipek * @dentry: pointer to dentry of the base directory 109616f18200SJosef 'Jeff' Sipek * @mnt: pointer to vfs mount of the base directory 109716f18200SJosef 'Jeff' Sipek * @name: pointer to file name 109816f18200SJosef 'Jeff' Sipek * @flags: lookup flags 109916f18200SJosef 'Jeff' Sipek * @nd: pointer to nameidata 110016f18200SJosef 'Jeff' Sipek */ 110116f18200SJosef 'Jeff' Sipek int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, 110216f18200SJosef 'Jeff' Sipek const char *name, unsigned int flags, 110316f18200SJosef 'Jeff' Sipek struct nameidata *nd) 110416f18200SJosef 'Jeff' Sipek { 110516f18200SJosef 'Jeff' Sipek int retval; 110616f18200SJosef 'Jeff' Sipek 110716f18200SJosef 'Jeff' Sipek /* same as do_path_lookup */ 110816f18200SJosef 'Jeff' Sipek nd->last_type = LAST_ROOT; 110916f18200SJosef 'Jeff' Sipek nd->flags = flags; 111016f18200SJosef 'Jeff' Sipek nd->depth = 0; 111116f18200SJosef 'Jeff' Sipek 1112c8e7f449SJan Blunck nd->path.dentry = dentry; 1113c8e7f449SJan Blunck nd->path.mnt = mnt; 1114c8e7f449SJan Blunck path_get(&nd->path); 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 112116f18200SJosef 'Jeff' Sipek return retval; 112216f18200SJosef 'Jeff' Sipek 112316f18200SJosef 'Jeff' Sipek } 112416f18200SJosef 'Jeff' Sipek 1125834f2a4aSTrond Myklebust /** 1126834f2a4aSTrond Myklebust * path_lookup_open - lookup a file path with open intent 11277045f37bSMartin Waitz * @dfd: the directory to use as base, or AT_FDCWD 1128834f2a4aSTrond Myklebust * @name: pointer to file name 1129834f2a4aSTrond Myklebust * @lookup_flags: lookup intent flags 1130834f2a4aSTrond Myklebust * @nd: pointer to nameidata 1131834f2a4aSTrond Myklebust * @open_flags: open intent flags 1132834f2a4aSTrond Myklebust */ 11335590ff0dSUlrich Drepper int path_lookup_open(int dfd, const char *name, unsigned int lookup_flags, 1134834f2a4aSTrond Myklebust struct nameidata *nd, int open_flags) 1135834f2a4aSTrond Myklebust { 11368737f3a1SAl Viro struct file *filp = get_empty_filp(); 11378737f3a1SAl Viro int err; 1138834f2a4aSTrond Myklebust 11398737f3a1SAl Viro if (filp == NULL) 11408737f3a1SAl Viro return -ENFILE; 11418737f3a1SAl Viro nd->intent.open.file = filp; 11428737f3a1SAl Viro nd->intent.open.flags = open_flags; 11438737f3a1SAl Viro nd->intent.open.create_mode = 0; 11448737f3a1SAl Viro err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); 11458737f3a1SAl Viro if (IS_ERR(nd->intent.open.file)) { 11468737f3a1SAl Viro if (err == 0) { 11478737f3a1SAl Viro err = PTR_ERR(nd->intent.open.file); 11488737f3a1SAl Viro path_put(&nd->path); 11498737f3a1SAl Viro } 11508737f3a1SAl Viro } else if (err != 0) 11518737f3a1SAl Viro release_open_intent(nd); 11528737f3a1SAl Viro return err; 1153834f2a4aSTrond Myklebust } 1154834f2a4aSTrond Myklebust 1155eead1911SChristoph Hellwig static struct dentry *__lookup_hash(struct qstr *name, 1156eead1911SChristoph Hellwig struct dentry *base, struct nameidata *nd) 11571da177e4SLinus Torvalds { 11581da177e4SLinus Torvalds struct dentry *dentry; 11591da177e4SLinus Torvalds struct inode *inode; 11601da177e4SLinus Torvalds int err; 11611da177e4SLinus Torvalds 11621da177e4SLinus Torvalds inode = base->d_inode; 11631da177e4SLinus Torvalds 11641da177e4SLinus Torvalds /* 11651da177e4SLinus Torvalds * See if the low-level filesystem might want 11661da177e4SLinus Torvalds * to use its own hash.. 11671da177e4SLinus Torvalds */ 11681da177e4SLinus Torvalds if (base->d_op && base->d_op->d_hash) { 11691da177e4SLinus Torvalds err = base->d_op->d_hash(base, name); 11701da177e4SLinus Torvalds dentry = ERR_PTR(err); 11711da177e4SLinus Torvalds if (err < 0) 11721da177e4SLinus Torvalds goto out; 11731da177e4SLinus Torvalds } 11741da177e4SLinus Torvalds 11751da177e4SLinus Torvalds dentry = cached_lookup(base, name, nd); 11761da177e4SLinus Torvalds if (!dentry) { 1177d70b67c8SMiklos Szeredi struct dentry *new; 1178d70b67c8SMiklos Szeredi 1179d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 1180d70b67c8SMiklos Szeredi dentry = ERR_PTR(-ENOENT); 1181d70b67c8SMiklos Szeredi if (IS_DEADDIR(inode)) 1182d70b67c8SMiklos Szeredi goto out; 1183d70b67c8SMiklos Szeredi 1184d70b67c8SMiklos Szeredi new = d_alloc(base, name); 11851da177e4SLinus Torvalds dentry = ERR_PTR(-ENOMEM); 11861da177e4SLinus Torvalds if (!new) 11871da177e4SLinus Torvalds goto out; 11881da177e4SLinus Torvalds dentry = inode->i_op->lookup(inode, new, nd); 11891da177e4SLinus Torvalds if (!dentry) 11901da177e4SLinus Torvalds dentry = new; 11911da177e4SLinus Torvalds else 11921da177e4SLinus Torvalds dput(new); 11931da177e4SLinus Torvalds } 11941da177e4SLinus Torvalds out: 11951da177e4SLinus Torvalds return dentry; 11961da177e4SLinus Torvalds } 11971da177e4SLinus Torvalds 1198057f6c01SJames Morris /* 1199057f6c01SJames Morris * Restricted form of lookup. Doesn't follow links, single-component only, 1200057f6c01SJames Morris * needs parent already locked. Doesn't follow mounts. 1201057f6c01SJames Morris * SMP-safe. 1202057f6c01SJames Morris */ 1203a244e169SAdrian Bunk static struct dentry *lookup_hash(struct nameidata *nd) 12041da177e4SLinus Torvalds { 1205eead1911SChristoph Hellwig int err; 1206eead1911SChristoph Hellwig 1207f419a2e3SAl Viro err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); 1208eead1911SChristoph Hellwig if (err) 1209eead1911SChristoph Hellwig return ERR_PTR(err); 12104ac91378SJan Blunck return __lookup_hash(&nd->last, nd->path.dentry, nd); 12111da177e4SLinus Torvalds } 12121da177e4SLinus Torvalds 1213eead1911SChristoph Hellwig static int __lookup_one_len(const char *name, struct qstr *this, 1214eead1911SChristoph Hellwig struct dentry *base, int len) 12151da177e4SLinus Torvalds { 12161da177e4SLinus Torvalds unsigned long hash; 12171da177e4SLinus Torvalds unsigned int c; 12181da177e4SLinus Torvalds 1219057f6c01SJames Morris this->name = name; 1220057f6c01SJames Morris this->len = len; 12211da177e4SLinus Torvalds if (!len) 1222057f6c01SJames Morris return -EACCES; 12231da177e4SLinus Torvalds 12241da177e4SLinus Torvalds hash = init_name_hash(); 12251da177e4SLinus Torvalds while (len--) { 12261da177e4SLinus Torvalds c = *(const unsigned char *)name++; 12271da177e4SLinus Torvalds if (c == '/' || c == '\0') 1228057f6c01SJames Morris return -EACCES; 12291da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 12301da177e4SLinus Torvalds } 1231057f6c01SJames Morris this->hash = end_name_hash(hash); 1232057f6c01SJames Morris return 0; 1233057f6c01SJames Morris } 12341da177e4SLinus Torvalds 1235eead1911SChristoph Hellwig /** 1236a6b91919SRandy Dunlap * lookup_one_len - filesystem helper to lookup single pathname component 1237eead1911SChristoph Hellwig * @name: pathname component to lookup 1238eead1911SChristoph Hellwig * @base: base directory to lookup from 1239eead1911SChristoph Hellwig * @len: maximum length @len should be interpreted to 1240eead1911SChristoph Hellwig * 1241a6b91919SRandy Dunlap * Note that this routine is purely a helper for filesystem usage and should 1242a6b91919SRandy Dunlap * not be called by generic code. Also note that by using this function the 1243eead1911SChristoph Hellwig * nameidata argument is passed to the filesystem methods and a filesystem 1244eead1911SChristoph Hellwig * using this helper needs to be prepared for that. 1245eead1911SChristoph Hellwig */ 1246057f6c01SJames Morris struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) 1247057f6c01SJames Morris { 1248057f6c01SJames Morris int err; 1249057f6c01SJames Morris struct qstr this; 1250057f6c01SJames Morris 12512f9092e1SDavid Woodhouse WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); 12522f9092e1SDavid Woodhouse 1253057f6c01SJames Morris err = __lookup_one_len(name, &this, base, len); 1254057f6c01SJames Morris if (err) 1255057f6c01SJames Morris return ERR_PTR(err); 1256eead1911SChristoph Hellwig 1257f419a2e3SAl Viro err = inode_permission(base->d_inode, MAY_EXEC); 1258eead1911SChristoph Hellwig if (err) 1259eead1911SChristoph Hellwig return ERR_PTR(err); 126049705b77SChristoph Hellwig return __lookup_hash(&this, base, NULL); 1261057f6c01SJames Morris } 1262057f6c01SJames Morris 1263eead1911SChristoph Hellwig /** 1264eead1911SChristoph Hellwig * lookup_one_noperm - bad hack for sysfs 1265eead1911SChristoph Hellwig * @name: pathname component to lookup 1266eead1911SChristoph Hellwig * @base: base directory to lookup from 1267eead1911SChristoph Hellwig * 1268eead1911SChristoph Hellwig * This is a variant of lookup_one_len that doesn't perform any permission 1269eead1911SChristoph Hellwig * checks. It's a horrible hack to work around the braindead sysfs 1270eead1911SChristoph Hellwig * architecture and should not be used anywhere else. 1271eead1911SChristoph Hellwig * 1272eead1911SChristoph Hellwig * DON'T USE THIS FUNCTION EVER, thanks. 1273eead1911SChristoph Hellwig */ 1274eead1911SChristoph Hellwig struct dentry *lookup_one_noperm(const char *name, struct dentry *base) 1275057f6c01SJames Morris { 1276057f6c01SJames Morris int err; 1277057f6c01SJames Morris struct qstr this; 1278057f6c01SJames Morris 1279eead1911SChristoph Hellwig err = __lookup_one_len(name, &this, base, strlen(name)); 1280057f6c01SJames Morris if (err) 1281057f6c01SJames Morris return ERR_PTR(err); 1282eead1911SChristoph Hellwig return __lookup_hash(&this, base, NULL); 12831da177e4SLinus Torvalds } 12841da177e4SLinus Torvalds 12852d8f3038SAl Viro int user_path_at(int dfd, const char __user *name, unsigned flags, 12862d8f3038SAl Viro struct path *path) 12871da177e4SLinus Torvalds { 12882d8f3038SAl Viro struct nameidata nd; 12891da177e4SLinus Torvalds char *tmp = getname(name); 12901da177e4SLinus Torvalds int err = PTR_ERR(tmp); 12911da177e4SLinus Torvalds if (!IS_ERR(tmp)) { 12922d8f3038SAl Viro 12932d8f3038SAl Viro BUG_ON(flags & LOOKUP_PARENT); 12942d8f3038SAl Viro 12952d8f3038SAl Viro err = do_path_lookup(dfd, tmp, flags, &nd); 12961da177e4SLinus Torvalds putname(tmp); 12972d8f3038SAl Viro if (!err) 12982d8f3038SAl Viro *path = nd.path; 12991da177e4SLinus Torvalds } 13001da177e4SLinus Torvalds return err; 13011da177e4SLinus Torvalds } 13021da177e4SLinus Torvalds 13032ad94ae6SAl Viro static int user_path_parent(int dfd, const char __user *path, 13042ad94ae6SAl Viro struct nameidata *nd, char **name) 13052ad94ae6SAl Viro { 13062ad94ae6SAl Viro char *s = getname(path); 13072ad94ae6SAl Viro int error; 13082ad94ae6SAl Viro 13092ad94ae6SAl Viro if (IS_ERR(s)) 13102ad94ae6SAl Viro return PTR_ERR(s); 13112ad94ae6SAl Viro 13122ad94ae6SAl Viro error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); 13132ad94ae6SAl Viro if (error) 13142ad94ae6SAl Viro putname(s); 13152ad94ae6SAl Viro else 13162ad94ae6SAl Viro *name = s; 13172ad94ae6SAl Viro 13182ad94ae6SAl Viro return error; 13192ad94ae6SAl Viro } 13202ad94ae6SAl Viro 13211da177e4SLinus Torvalds /* 13221da177e4SLinus Torvalds * It's inline, so penalty for filesystems that don't use sticky bit is 13231da177e4SLinus Torvalds * minimal. 13241da177e4SLinus Torvalds */ 13251da177e4SLinus Torvalds static inline int check_sticky(struct inode *dir, struct inode *inode) 13261da177e4SLinus Torvalds { 1327da9592edSDavid Howells uid_t fsuid = current_fsuid(); 1328da9592edSDavid Howells 13291da177e4SLinus Torvalds if (!(dir->i_mode & S_ISVTX)) 13301da177e4SLinus Torvalds return 0; 1331da9592edSDavid Howells if (inode->i_uid == fsuid) 13321da177e4SLinus Torvalds return 0; 1333da9592edSDavid Howells if (dir->i_uid == fsuid) 13341da177e4SLinus Torvalds return 0; 13351da177e4SLinus Torvalds return !capable(CAP_FOWNER); 13361da177e4SLinus Torvalds } 13371da177e4SLinus Torvalds 13381da177e4SLinus Torvalds /* 13391da177e4SLinus Torvalds * Check whether we can remove a link victim from directory dir, check 13401da177e4SLinus Torvalds * whether the type of victim is right. 13411da177e4SLinus Torvalds * 1. We can't do it if dir is read-only (done in permission()) 13421da177e4SLinus Torvalds * 2. We should have write and exec permissions on dir 13431da177e4SLinus Torvalds * 3. We can't remove anything from append-only dir 13441da177e4SLinus Torvalds * 4. We can't do anything with immutable dir (done in permission()) 13451da177e4SLinus Torvalds * 5. If the sticky bit on dir is set we should either 13461da177e4SLinus Torvalds * a. be owner of dir, or 13471da177e4SLinus Torvalds * b. be owner of victim, or 13481da177e4SLinus Torvalds * c. have CAP_FOWNER capability 13491da177e4SLinus Torvalds * 6. If the victim is append-only or immutable we can't do antyhing with 13501da177e4SLinus Torvalds * links pointing to it. 13511da177e4SLinus Torvalds * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. 13521da177e4SLinus Torvalds * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. 13531da177e4SLinus Torvalds * 9. We can't remove a root or mountpoint. 13541da177e4SLinus Torvalds * 10. We don't allow removal of NFS sillyrenamed files; it's handled by 13551da177e4SLinus Torvalds * nfs_async_unlink(). 13561da177e4SLinus Torvalds */ 1357858119e1SArjan van de Ven static int may_delete(struct inode *dir,struct dentry *victim,int isdir) 13581da177e4SLinus Torvalds { 13591da177e4SLinus Torvalds int error; 13601da177e4SLinus Torvalds 13611da177e4SLinus Torvalds if (!victim->d_inode) 13621da177e4SLinus Torvalds return -ENOENT; 13631da177e4SLinus Torvalds 13641da177e4SLinus Torvalds BUG_ON(victim->d_parent->d_inode != dir); 13655a190ae6SAl Viro audit_inode_child(victim->d_name.name, victim, dir); 13661da177e4SLinus Torvalds 1367f419a2e3SAl Viro error = inode_permission(dir, MAY_WRITE | MAY_EXEC); 13681da177e4SLinus Torvalds if (error) 13691da177e4SLinus Torvalds return error; 13701da177e4SLinus Torvalds if (IS_APPEND(dir)) 13711da177e4SLinus Torvalds return -EPERM; 13721da177e4SLinus Torvalds if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| 1373f9454548SHugh Dickins IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) 13741da177e4SLinus Torvalds return -EPERM; 13751da177e4SLinus Torvalds if (isdir) { 13761da177e4SLinus Torvalds if (!S_ISDIR(victim->d_inode->i_mode)) 13771da177e4SLinus Torvalds return -ENOTDIR; 13781da177e4SLinus Torvalds if (IS_ROOT(victim)) 13791da177e4SLinus Torvalds return -EBUSY; 13801da177e4SLinus Torvalds } else if (S_ISDIR(victim->d_inode->i_mode)) 13811da177e4SLinus Torvalds return -EISDIR; 13821da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 13831da177e4SLinus Torvalds return -ENOENT; 13841da177e4SLinus Torvalds if (victim->d_flags & DCACHE_NFSFS_RENAMED) 13851da177e4SLinus Torvalds return -EBUSY; 13861da177e4SLinus Torvalds return 0; 13871da177e4SLinus Torvalds } 13881da177e4SLinus Torvalds 13891da177e4SLinus Torvalds /* Check whether we can create an object with dentry child in directory 13901da177e4SLinus Torvalds * dir. 13911da177e4SLinus Torvalds * 1. We can't do it if child already exists (open has special treatment for 13921da177e4SLinus Torvalds * this case, but since we are inlined it's OK) 13931da177e4SLinus Torvalds * 2. We can't do it if dir is read-only (done in permission()) 13941da177e4SLinus Torvalds * 3. We should have write and exec permissions on dir 13951da177e4SLinus Torvalds * 4. We can't do it if dir is immutable (done in permission()) 13961da177e4SLinus Torvalds */ 1397a95164d9SMiklos Szeredi static inline int may_create(struct inode *dir, struct dentry *child) 13981da177e4SLinus Torvalds { 13991da177e4SLinus Torvalds if (child->d_inode) 14001da177e4SLinus Torvalds return -EEXIST; 14011da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 14021da177e4SLinus Torvalds return -ENOENT; 1403f419a2e3SAl Viro return inode_permission(dir, MAY_WRITE | MAY_EXEC); 14041da177e4SLinus Torvalds } 14051da177e4SLinus Torvalds 14061da177e4SLinus Torvalds /* 14071da177e4SLinus Torvalds * O_DIRECTORY translates into forcing a directory lookup. 14081da177e4SLinus Torvalds */ 14091da177e4SLinus Torvalds static inline int lookup_flags(unsigned int f) 14101da177e4SLinus Torvalds { 14111da177e4SLinus Torvalds unsigned long retval = LOOKUP_FOLLOW; 14121da177e4SLinus Torvalds 14131da177e4SLinus Torvalds if (f & O_NOFOLLOW) 14141da177e4SLinus Torvalds retval &= ~LOOKUP_FOLLOW; 14151da177e4SLinus Torvalds 14161da177e4SLinus Torvalds if (f & O_DIRECTORY) 14171da177e4SLinus Torvalds retval |= LOOKUP_DIRECTORY; 14181da177e4SLinus Torvalds 14191da177e4SLinus Torvalds return retval; 14201da177e4SLinus Torvalds } 14211da177e4SLinus Torvalds 14221da177e4SLinus Torvalds /* 14231da177e4SLinus Torvalds * p1 and p2 should be directories on the same fs. 14241da177e4SLinus Torvalds */ 14251da177e4SLinus Torvalds struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) 14261da177e4SLinus Torvalds { 14271da177e4SLinus Torvalds struct dentry *p; 14281da177e4SLinus Torvalds 14291da177e4SLinus Torvalds if (p1 == p2) { 1430f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 14311da177e4SLinus Torvalds return NULL; 14321da177e4SLinus Torvalds } 14331da177e4SLinus Torvalds 1434a11f3a05SArjan van de Ven mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14351da177e4SLinus Torvalds 1436e2761a11SOGAWA Hirofumi p = d_ancestor(p2, p1); 1437e2761a11SOGAWA Hirofumi if (p) { 1438f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); 1439f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); 14401da177e4SLinus Torvalds return p; 14411da177e4SLinus Torvalds } 14421da177e4SLinus Torvalds 1443e2761a11SOGAWA Hirofumi p = d_ancestor(p1, p2); 1444e2761a11SOGAWA Hirofumi if (p) { 1445f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1446f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14471da177e4SLinus Torvalds return p; 14481da177e4SLinus Torvalds } 14491da177e4SLinus Torvalds 1450f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1451f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14521da177e4SLinus Torvalds return NULL; 14531da177e4SLinus Torvalds } 14541da177e4SLinus Torvalds 14551da177e4SLinus Torvalds void unlock_rename(struct dentry *p1, struct dentry *p2) 14561da177e4SLinus Torvalds { 14571b1dcc1bSJes Sorensen mutex_unlock(&p1->d_inode->i_mutex); 14581da177e4SLinus Torvalds if (p1 != p2) { 14591b1dcc1bSJes Sorensen mutex_unlock(&p2->d_inode->i_mutex); 1460a11f3a05SArjan van de Ven mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14611da177e4SLinus Torvalds } 14621da177e4SLinus Torvalds } 14631da177e4SLinus Torvalds 14641da177e4SLinus Torvalds int vfs_create(struct inode *dir, struct dentry *dentry, int mode, 14651da177e4SLinus Torvalds struct nameidata *nd) 14661da177e4SLinus Torvalds { 1467a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 14681da177e4SLinus Torvalds 14691da177e4SLinus Torvalds if (error) 14701da177e4SLinus Torvalds return error; 14711da177e4SLinus Torvalds 1472acfa4380SAl Viro if (!dir->i_op->create) 14731da177e4SLinus Torvalds return -EACCES; /* shouldn't it be ENOSYS? */ 14741da177e4SLinus Torvalds mode &= S_IALLUGO; 14751da177e4SLinus Torvalds mode |= S_IFREG; 14761da177e4SLinus Torvalds error = security_inode_create(dir, dentry, mode); 14771da177e4SLinus Torvalds if (error) 14781da177e4SLinus Torvalds return error; 14799e3509e2SJan Kara vfs_dq_init(dir); 14801da177e4SLinus Torvalds error = dir->i_op->create(dir, dentry, mode, nd); 1481a74574aaSStephen Smalley if (!error) 1482f38aa942SAmy Griffis fsnotify_create(dir, dentry); 14831da177e4SLinus Torvalds return error; 14841da177e4SLinus Torvalds } 14851da177e4SLinus Torvalds 14863fb64190SChristoph Hellwig int may_open(struct path *path, int acc_mode, int flag) 14871da177e4SLinus Torvalds { 14883fb64190SChristoph Hellwig struct dentry *dentry = path->dentry; 14891da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 14901da177e4SLinus Torvalds int error; 14911da177e4SLinus Torvalds 14921da177e4SLinus Torvalds if (!inode) 14931da177e4SLinus Torvalds return -ENOENT; 14941da177e4SLinus Torvalds 1495c8fe8f30SChristoph Hellwig switch (inode->i_mode & S_IFMT) { 1496c8fe8f30SChristoph Hellwig case S_IFLNK: 14971da177e4SLinus Torvalds return -ELOOP; 1498c8fe8f30SChristoph Hellwig case S_IFDIR: 1499c8fe8f30SChristoph Hellwig if (acc_mode & MAY_WRITE) 15001da177e4SLinus Torvalds return -EISDIR; 1501c8fe8f30SChristoph Hellwig break; 1502c8fe8f30SChristoph Hellwig case S_IFBLK: 1503c8fe8f30SChristoph Hellwig case S_IFCHR: 15043fb64190SChristoph Hellwig if (path->mnt->mnt_flags & MNT_NODEV) 15051da177e4SLinus Torvalds return -EACCES; 1506c8fe8f30SChristoph Hellwig /*FALLTHRU*/ 1507c8fe8f30SChristoph Hellwig case S_IFIFO: 1508c8fe8f30SChristoph Hellwig case S_IFSOCK: 15091da177e4SLinus Torvalds flag &= ~O_TRUNC; 1510c8fe8f30SChristoph Hellwig break; 15114a3fd211SDave Hansen } 1512b41572e9SDave Hansen 15133fb64190SChristoph Hellwig error = inode_permission(inode, acc_mode); 1514b41572e9SDave Hansen if (error) 1515b41572e9SDave Hansen return error; 15166146f0d5SMimi Zohar 1517cb5629b1SJames Morris error = ima_path_check(path, 15186146f0d5SMimi Zohar acc_mode & (MAY_READ | MAY_WRITE | MAY_EXEC)); 15196146f0d5SMimi Zohar if (error) 15206146f0d5SMimi Zohar return error; 15211da177e4SLinus Torvalds /* 15221da177e4SLinus Torvalds * An append-only file must be opened in append mode for writing. 15231da177e4SLinus Torvalds */ 15241da177e4SLinus Torvalds if (IS_APPEND(inode)) { 15251da177e4SLinus Torvalds if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) 15261da177e4SLinus Torvalds return -EPERM; 15271da177e4SLinus Torvalds if (flag & O_TRUNC) 15281da177e4SLinus Torvalds return -EPERM; 15291da177e4SLinus Torvalds } 15301da177e4SLinus Torvalds 15311da177e4SLinus Torvalds /* O_NOATIME can only be set by the owner or superuser */ 15321da177e4SLinus Torvalds if (flag & O_NOATIME) 15333bd858abSSatyam Sharma if (!is_owner_or_cap(inode)) 15341da177e4SLinus Torvalds return -EPERM; 15351da177e4SLinus Torvalds 15361da177e4SLinus Torvalds /* 15371da177e4SLinus Torvalds * Ensure there are no outstanding leases on the file. 15381da177e4SLinus Torvalds */ 15391da177e4SLinus Torvalds error = break_lease(inode, flag); 15401da177e4SLinus Torvalds if (error) 15411da177e4SLinus Torvalds return error; 15421da177e4SLinus Torvalds 15431da177e4SLinus Torvalds if (flag & O_TRUNC) { 15441da177e4SLinus Torvalds error = get_write_access(inode); 15451da177e4SLinus Torvalds if (error) 15461da177e4SLinus Torvalds return error; 15471da177e4SLinus Torvalds 15481da177e4SLinus Torvalds /* 15491da177e4SLinus Torvalds * Refuse to truncate files with mandatory locks held on them. 15501da177e4SLinus Torvalds */ 15511da177e4SLinus Torvalds error = locks_verify_locked(inode); 1552be6d3e56SKentaro Takeda if (!error) 15533fb64190SChristoph Hellwig error = security_path_truncate(path, 0, 1554be6d3e56SKentaro Takeda ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); 15551da177e4SLinus Torvalds if (!error) { 15569e3509e2SJan Kara vfs_dq_init(inode); 15571da177e4SLinus Torvalds 1558d139d7ffSMiklos Szeredi error = do_truncate(dentry, 0, 1559d139d7ffSMiklos Szeredi ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, 1560d139d7ffSMiklos Szeredi NULL); 15611da177e4SLinus Torvalds } 15621da177e4SLinus Torvalds put_write_access(inode); 15631da177e4SLinus Torvalds if (error) 15641da177e4SLinus Torvalds return error; 15651da177e4SLinus Torvalds } else 15661da177e4SLinus Torvalds if (flag & FMODE_WRITE) 15679e3509e2SJan Kara vfs_dq_init(inode); 15681da177e4SLinus Torvalds 15691da177e4SLinus Torvalds return 0; 15701da177e4SLinus Torvalds } 15711da177e4SLinus Torvalds 1572d57999e1SDave Hansen /* 1573d57999e1SDave Hansen * Be careful about ever adding any more callers of this 1574d57999e1SDave Hansen * function. Its flags must be in the namei format, not 1575d57999e1SDave Hansen * what get passed to sys_open(). 1576d57999e1SDave Hansen */ 1577d57999e1SDave Hansen static int __open_namei_create(struct nameidata *nd, struct path *path, 1578aab520e2SDave Hansen int flag, int mode) 1579aab520e2SDave Hansen { 1580aab520e2SDave Hansen int error; 15814ac91378SJan Blunck struct dentry *dir = nd->path.dentry; 1582aab520e2SDave Hansen 1583aab520e2SDave Hansen if (!IS_POSIXACL(dir->d_inode)) 1584ce3b0f8dSAl Viro mode &= ~current_umask(); 1585be6d3e56SKentaro Takeda error = security_path_mknod(&nd->path, path->dentry, mode, 0); 1586be6d3e56SKentaro Takeda if (error) 1587be6d3e56SKentaro Takeda goto out_unlock; 1588aab520e2SDave Hansen error = vfs_create(dir->d_inode, path->dentry, mode, nd); 1589be6d3e56SKentaro Takeda out_unlock: 1590aab520e2SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 15914ac91378SJan Blunck dput(nd->path.dentry); 15924ac91378SJan Blunck nd->path.dentry = path->dentry; 1593aab520e2SDave Hansen if (error) 1594aab520e2SDave Hansen return error; 1595aab520e2SDave Hansen /* Don't check for write permission, don't truncate */ 15963fb64190SChristoph Hellwig return may_open(&nd->path, 0, flag & ~O_TRUNC); 1597aab520e2SDave Hansen } 1598aab520e2SDave Hansen 15991da177e4SLinus Torvalds /* 1600d57999e1SDave Hansen * Note that while the flag value (low two bits) for sys_open means: 1601d57999e1SDave Hansen * 00 - read-only 1602d57999e1SDave Hansen * 01 - write-only 1603d57999e1SDave Hansen * 10 - read-write 1604d57999e1SDave Hansen * 11 - special 1605d57999e1SDave Hansen * it is changed into 1606d57999e1SDave Hansen * 00 - no permissions needed 1607d57999e1SDave Hansen * 01 - read-permission 1608d57999e1SDave Hansen * 10 - write-permission 1609d57999e1SDave Hansen * 11 - read-write 1610d57999e1SDave Hansen * for the internal routines (ie open_namei()/follow_link() etc) 1611d57999e1SDave Hansen * This is more logical, and also allows the 00 "no perm needed" 1612d57999e1SDave Hansen * to be used for symlinks (where the permissions are checked 1613d57999e1SDave Hansen * later). 1614d57999e1SDave Hansen * 1615d57999e1SDave Hansen */ 1616d57999e1SDave Hansen static inline int open_to_namei_flags(int flag) 1617d57999e1SDave Hansen { 1618d57999e1SDave Hansen if ((flag+1) & O_ACCMODE) 1619d57999e1SDave Hansen flag++; 1620d57999e1SDave Hansen return flag; 1621d57999e1SDave Hansen } 1622d57999e1SDave Hansen 16234a3fd211SDave Hansen static int open_will_write_to_fs(int flag, struct inode *inode) 16244a3fd211SDave Hansen { 1625d57999e1SDave Hansen /* 16264a3fd211SDave Hansen * We'll never write to the fs underlying 16274a3fd211SDave Hansen * a device file. 16284a3fd211SDave Hansen */ 16294a3fd211SDave Hansen if (special_file(inode->i_mode)) 16304a3fd211SDave Hansen return 0; 16314a3fd211SDave Hansen return (flag & O_TRUNC); 16324a3fd211SDave Hansen } 16334a3fd211SDave Hansen 16344a3fd211SDave Hansen /* 16354a3fd211SDave Hansen * Note that the low bits of the passed in "open_flag" 16364a3fd211SDave Hansen * are not the same as in the local variable "flag". See 16374a3fd211SDave Hansen * open_to_namei_flags() for more details. 16381da177e4SLinus Torvalds */ 1639a70e65dfSChristoph Hellwig struct file *do_filp_open(int dfd, const char *pathname, 1640a70e65dfSChristoph Hellwig int open_flag, int mode) 16411da177e4SLinus Torvalds { 16424a3fd211SDave Hansen struct file *filp; 1643a70e65dfSChristoph Hellwig struct nameidata nd; 1644834f2a4aSTrond Myklebust int acc_mode, error; 16454e7506e4SAl Viro struct path path; 16461da177e4SLinus Torvalds struct dentry *dir; 16471da177e4SLinus Torvalds int count = 0; 16484a3fd211SDave Hansen int will_write; 1649d57999e1SDave Hansen int flag = open_to_namei_flags(open_flag); 16501da177e4SLinus Torvalds 1651b77b0646SAl Viro acc_mode = MAY_OPEN | ACC_MODE(flag); 16521da177e4SLinus Torvalds 1653834f2a4aSTrond Myklebust /* O_TRUNC implies we need access checks for write permissions */ 1654834f2a4aSTrond Myklebust if (flag & O_TRUNC) 1655834f2a4aSTrond Myklebust acc_mode |= MAY_WRITE; 1656834f2a4aSTrond Myklebust 16571da177e4SLinus Torvalds /* Allow the LSM permission hook to distinguish append 16581da177e4SLinus Torvalds access from general write access. */ 16591da177e4SLinus Torvalds if (flag & O_APPEND) 16601da177e4SLinus Torvalds acc_mode |= MAY_APPEND; 16611da177e4SLinus Torvalds 16621da177e4SLinus Torvalds /* 16631da177e4SLinus Torvalds * The simplest case - just a plain lookup. 16641da177e4SLinus Torvalds */ 16651da177e4SLinus Torvalds if (!(flag & O_CREAT)) { 16665590ff0dSUlrich Drepper error = path_lookup_open(dfd, pathname, lookup_flags(flag), 1667a70e65dfSChristoph Hellwig &nd, flag); 16681da177e4SLinus Torvalds if (error) 1669a70e65dfSChristoph Hellwig return ERR_PTR(error); 16701da177e4SLinus Torvalds goto ok; 16711da177e4SLinus Torvalds } 16721da177e4SLinus Torvalds 16731da177e4SLinus Torvalds /* 16741da177e4SLinus Torvalds * Create - we need to know the parent. 16751da177e4SLinus Torvalds */ 16768737f3a1SAl Viro error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); 16771da177e4SLinus Torvalds if (error) 1678a70e65dfSChristoph Hellwig return ERR_PTR(error); 16791da177e4SLinus Torvalds 16801da177e4SLinus Torvalds /* 16811da177e4SLinus Torvalds * We have the parent and last component. First of all, check 16821da177e4SLinus Torvalds * that we are not asked to creat(2) an obvious directory - that 16831da177e4SLinus Torvalds * will not do. 16841da177e4SLinus Torvalds */ 16851da177e4SLinus Torvalds error = -EISDIR; 1686a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) 16878737f3a1SAl Viro goto exit_parent; 16881da177e4SLinus Torvalds 16898737f3a1SAl Viro error = -ENFILE; 16908737f3a1SAl Viro filp = get_empty_filp(); 16918737f3a1SAl Viro if (filp == NULL) 16928737f3a1SAl Viro goto exit_parent; 16938737f3a1SAl Viro nd.intent.open.file = filp; 16948737f3a1SAl Viro nd.intent.open.flags = flag; 16958737f3a1SAl Viro nd.intent.open.create_mode = mode; 1696a70e65dfSChristoph Hellwig dir = nd.path.dentry; 1697a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 16988737f3a1SAl Viro nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; 16993516586aSAl Viro if (flag & O_EXCL) 17003516586aSAl Viro nd.flags |= LOOKUP_EXCL; 17011b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1702a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1703a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 17041da177e4SLinus Torvalds 17051da177e4SLinus Torvalds do_last: 17064e7506e4SAl Viro error = PTR_ERR(path.dentry); 17074e7506e4SAl Viro if (IS_ERR(path.dentry)) { 17081b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17091da177e4SLinus Torvalds goto exit; 17101da177e4SLinus Torvalds } 17111da177e4SLinus Torvalds 1712a70e65dfSChristoph Hellwig if (IS_ERR(nd.intent.open.file)) { 1713a70e65dfSChristoph Hellwig error = PTR_ERR(nd.intent.open.file); 17144a3fd211SDave Hansen goto exit_mutex_unlock; 17154af4c52fSOleg Drokin } 17164af4c52fSOleg Drokin 17171da177e4SLinus Torvalds /* Negative dentry, just create the file */ 17184e7506e4SAl Viro if (!path.dentry->d_inode) { 17194a3fd211SDave Hansen /* 17204a3fd211SDave Hansen * This write is needed to ensure that a 17214a3fd211SDave Hansen * ro->rw transition does not occur between 17224a3fd211SDave Hansen * the time when the file is created and when 17234a3fd211SDave Hansen * a permanent write count is taken through 17244a3fd211SDave Hansen * the 'struct file' in nameidata_to_filp(). 17254a3fd211SDave Hansen */ 17264a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17271da177e4SLinus Torvalds if (error) 17284a3fd211SDave Hansen goto exit_mutex_unlock; 17294a3fd211SDave Hansen error = __open_namei_create(&nd, &path, flag, mode); 17304a3fd211SDave Hansen if (error) { 17314a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17321da177e4SLinus Torvalds goto exit; 17334a3fd211SDave Hansen } 17344a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 17354a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17364a3fd211SDave Hansen return filp; 17371da177e4SLinus Torvalds } 17381da177e4SLinus Torvalds 17391da177e4SLinus Torvalds /* 17401da177e4SLinus Torvalds * It already exists. 17411da177e4SLinus Torvalds */ 17421b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17435a190ae6SAl Viro audit_inode(pathname, path.dentry); 17441da177e4SLinus Torvalds 17451da177e4SLinus Torvalds error = -EEXIST; 17461da177e4SLinus Torvalds if (flag & O_EXCL) 17471da177e4SLinus Torvalds goto exit_dput; 17481da177e4SLinus Torvalds 1749e13b210fSAl Viro if (__follow_mount(&path)) { 17501da177e4SLinus Torvalds error = -ELOOP; 1751ba7a4c1aSAl Viro if (flag & O_NOFOLLOW) 1752ba7a4c1aSAl Viro goto exit_dput; 17531da177e4SLinus Torvalds } 17543e2efce0SAmy Griffis 17551da177e4SLinus Torvalds error = -ENOENT; 17564e7506e4SAl Viro if (!path.dentry->d_inode) 17571da177e4SLinus Torvalds goto exit_dput; 1758acfa4380SAl Viro if (path.dentry->d_inode->i_op->follow_link) 17591da177e4SLinus Torvalds goto do_link; 17601da177e4SLinus Torvalds 1761a70e65dfSChristoph Hellwig path_to_nameidata(&path, &nd); 17621da177e4SLinus Torvalds error = -EISDIR; 17634e7506e4SAl Viro if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) 17641da177e4SLinus Torvalds goto exit; 17651da177e4SLinus Torvalds ok: 17664a3fd211SDave Hansen /* 17674a3fd211SDave Hansen * Consider: 17684a3fd211SDave Hansen * 1. may_open() truncates a file 17694a3fd211SDave Hansen * 2. a rw->ro mount transition occurs 17704a3fd211SDave Hansen * 3. nameidata_to_filp() fails due to 17714a3fd211SDave Hansen * the ro mount. 17724a3fd211SDave Hansen * That would be inconsistent, and should 17734a3fd211SDave Hansen * be avoided. Taking this mnt write here 17744a3fd211SDave Hansen * ensures that (2) can not occur. 17754a3fd211SDave Hansen */ 17764a3fd211SDave Hansen will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); 17774a3fd211SDave Hansen if (will_write) { 17784a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17791da177e4SLinus Torvalds if (error) 17801da177e4SLinus Torvalds goto exit; 17814a3fd211SDave Hansen } 17823fb64190SChristoph Hellwig error = may_open(&nd.path, acc_mode, flag); 17834a3fd211SDave Hansen if (error) { 17844a3fd211SDave Hansen if (will_write) 17854a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17864a3fd211SDave Hansen goto exit; 17874a3fd211SDave Hansen } 17884a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 17894a3fd211SDave Hansen /* 17904a3fd211SDave Hansen * It is now safe to drop the mnt write 17914a3fd211SDave Hansen * because the filp has had a write taken 17924a3fd211SDave Hansen * on its behalf. 17934a3fd211SDave Hansen */ 17944a3fd211SDave Hansen if (will_write) 17954a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17964a3fd211SDave Hansen return filp; 17971da177e4SLinus Torvalds 17984a3fd211SDave Hansen exit_mutex_unlock: 17994a3fd211SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 18001da177e4SLinus Torvalds exit_dput: 1801a70e65dfSChristoph Hellwig path_put_conditional(&path, &nd); 18021da177e4SLinus Torvalds exit: 1803a70e65dfSChristoph Hellwig if (!IS_ERR(nd.intent.open.file)) 1804a70e65dfSChristoph Hellwig release_open_intent(&nd); 18058737f3a1SAl Viro exit_parent: 1806a70e65dfSChristoph Hellwig path_put(&nd.path); 1807a70e65dfSChristoph Hellwig return ERR_PTR(error); 18081da177e4SLinus Torvalds 18091da177e4SLinus Torvalds do_link: 18101da177e4SLinus Torvalds error = -ELOOP; 18111da177e4SLinus Torvalds if (flag & O_NOFOLLOW) 18121da177e4SLinus Torvalds goto exit_dput; 18131da177e4SLinus Torvalds /* 18141da177e4SLinus Torvalds * This is subtle. Instead of calling do_follow_link() we do the 18151da177e4SLinus Torvalds * thing by hands. The reason is that this way we have zero link_count 18161da177e4SLinus Torvalds * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. 18171da177e4SLinus Torvalds * After that we have the parent and last component, i.e. 18181da177e4SLinus Torvalds * we are in the same situation as after the first path_walk(). 18191da177e4SLinus Torvalds * Well, almost - if the last component is normal we get its copy 18201da177e4SLinus Torvalds * stored in nd->last.name and we will have to putname() it when we 18211da177e4SLinus Torvalds * are done. Procfs-like symlinks just set LAST_BIND. 18221da177e4SLinus Torvalds */ 1823a70e65dfSChristoph Hellwig nd.flags |= LOOKUP_PARENT; 1824a70e65dfSChristoph Hellwig error = security_inode_follow_link(path.dentry, &nd); 18251da177e4SLinus Torvalds if (error) 18261da177e4SLinus Torvalds goto exit_dput; 1827a70e65dfSChristoph Hellwig error = __do_follow_link(&path, &nd); 1828de459215SKirill Korotaev if (error) { 1829de459215SKirill Korotaev /* Does someone understand code flow here? Or it is only 1830de459215SKirill Korotaev * me so stupid? Anathema to whoever designed this non-sense 1831de459215SKirill Korotaev * with "intent.open". 1832de459215SKirill Korotaev */ 1833a70e65dfSChristoph Hellwig release_open_intent(&nd); 1834a70e65dfSChristoph Hellwig return ERR_PTR(error); 1835de459215SKirill Korotaev } 1836a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 1837a70e65dfSChristoph Hellwig if (nd.last_type == LAST_BIND) 18381da177e4SLinus Torvalds goto ok; 18391da177e4SLinus Torvalds error = -EISDIR; 1840a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM) 18411da177e4SLinus Torvalds goto exit; 1842a70e65dfSChristoph Hellwig if (nd.last.name[nd.last.len]) { 1843a70e65dfSChristoph Hellwig __putname(nd.last.name); 18441da177e4SLinus Torvalds goto exit; 18451da177e4SLinus Torvalds } 18461da177e4SLinus Torvalds error = -ELOOP; 18471da177e4SLinus Torvalds if (count++==32) { 1848a70e65dfSChristoph Hellwig __putname(nd.last.name); 18491da177e4SLinus Torvalds goto exit; 18501da177e4SLinus Torvalds } 1851a70e65dfSChristoph Hellwig dir = nd.path.dentry; 18521b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1853a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1854a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 1855a70e65dfSChristoph Hellwig __putname(nd.last.name); 18561da177e4SLinus Torvalds goto do_last; 18571da177e4SLinus Torvalds } 18581da177e4SLinus Torvalds 18591da177e4SLinus Torvalds /** 1860a70e65dfSChristoph Hellwig * filp_open - open file and return file pointer 1861a70e65dfSChristoph Hellwig * 1862a70e65dfSChristoph Hellwig * @filename: path to open 1863a70e65dfSChristoph Hellwig * @flags: open flags as per the open(2) second argument 1864a70e65dfSChristoph Hellwig * @mode: mode for the new file if O_CREAT is set, else ignored 1865a70e65dfSChristoph Hellwig * 1866a70e65dfSChristoph Hellwig * This is the helper to open a file from kernelspace if you really 1867a70e65dfSChristoph Hellwig * have to. But in generally you should not do this, so please move 1868a70e65dfSChristoph Hellwig * along, nothing to see here.. 1869a70e65dfSChristoph Hellwig */ 1870a70e65dfSChristoph Hellwig struct file *filp_open(const char *filename, int flags, int mode) 1871a70e65dfSChristoph Hellwig { 1872a70e65dfSChristoph Hellwig return do_filp_open(AT_FDCWD, filename, flags, mode); 1873a70e65dfSChristoph Hellwig } 1874a70e65dfSChristoph Hellwig EXPORT_SYMBOL(filp_open); 1875a70e65dfSChristoph Hellwig 1876a70e65dfSChristoph Hellwig /** 18771da177e4SLinus Torvalds * lookup_create - lookup a dentry, creating it if it doesn't exist 18781da177e4SLinus Torvalds * @nd: nameidata info 18791da177e4SLinus Torvalds * @is_dir: directory flag 18801da177e4SLinus Torvalds * 18811da177e4SLinus Torvalds * Simple function to lookup and return a dentry and create it 18821da177e4SLinus Torvalds * if it doesn't exist. Is SMP-safe. 1883c663e5d8SChristoph Hellwig * 18844ac91378SJan Blunck * Returns with nd->path.dentry->d_inode->i_mutex locked. 18851da177e4SLinus Torvalds */ 18861da177e4SLinus Torvalds struct dentry *lookup_create(struct nameidata *nd, int is_dir) 18871da177e4SLinus Torvalds { 1888c663e5d8SChristoph Hellwig struct dentry *dentry = ERR_PTR(-EEXIST); 18891da177e4SLinus Torvalds 18904ac91378SJan Blunck mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 1891c663e5d8SChristoph Hellwig /* 1892c663e5d8SChristoph Hellwig * Yucky last component or no last component at all? 1893c663e5d8SChristoph Hellwig * (foo/., foo/.., /////) 1894c663e5d8SChristoph Hellwig */ 18951da177e4SLinus Torvalds if (nd->last_type != LAST_NORM) 18961da177e4SLinus Torvalds goto fail; 18971da177e4SLinus Torvalds nd->flags &= ~LOOKUP_PARENT; 18983516586aSAl Viro nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; 1899a634904aSASANO Masahiro nd->intent.open.flags = O_EXCL; 1900c663e5d8SChristoph Hellwig 1901c663e5d8SChristoph Hellwig /* 1902c663e5d8SChristoph Hellwig * Do the final lookup. 1903c663e5d8SChristoph Hellwig */ 190449705b77SChristoph Hellwig dentry = lookup_hash(nd); 19051da177e4SLinus Torvalds if (IS_ERR(dentry)) 19061da177e4SLinus Torvalds goto fail; 1907c663e5d8SChristoph Hellwig 1908e9baf6e5SAl Viro if (dentry->d_inode) 1909e9baf6e5SAl Viro goto eexist; 1910c663e5d8SChristoph Hellwig /* 1911c663e5d8SChristoph Hellwig * Special case - lookup gave negative, but... we had foo/bar/ 1912c663e5d8SChristoph Hellwig * From the vfs_mknod() POV we just have a negative dentry - 1913c663e5d8SChristoph Hellwig * all is fine. Let's be bastards - you had / on the end, you've 1914c663e5d8SChristoph Hellwig * been asking for (non-existent) directory. -ENOENT for you. 1915c663e5d8SChristoph Hellwig */ 1916e9baf6e5SAl Viro if (unlikely(!is_dir && nd->last.name[nd->last.len])) { 19171da177e4SLinus Torvalds dput(dentry); 19181da177e4SLinus Torvalds dentry = ERR_PTR(-ENOENT); 1919e9baf6e5SAl Viro } 1920e9baf6e5SAl Viro return dentry; 1921e9baf6e5SAl Viro eexist: 1922e9baf6e5SAl Viro dput(dentry); 1923e9baf6e5SAl Viro dentry = ERR_PTR(-EEXIST); 19241da177e4SLinus Torvalds fail: 19251da177e4SLinus Torvalds return dentry; 19261da177e4SLinus Torvalds } 1927f81a0bffSChristoph Hellwig EXPORT_SYMBOL_GPL(lookup_create); 19281da177e4SLinus Torvalds 19291da177e4SLinus Torvalds int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 19301da177e4SLinus Torvalds { 1931a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 19321da177e4SLinus Torvalds 19331da177e4SLinus Torvalds if (error) 19341da177e4SLinus Torvalds return error; 19351da177e4SLinus Torvalds 19361da177e4SLinus Torvalds if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) 19371da177e4SLinus Torvalds return -EPERM; 19381da177e4SLinus Torvalds 1939acfa4380SAl Viro if (!dir->i_op->mknod) 19401da177e4SLinus Torvalds return -EPERM; 19411da177e4SLinus Torvalds 194208ce5f16SSerge E. Hallyn error = devcgroup_inode_mknod(mode, dev); 194308ce5f16SSerge E. Hallyn if (error) 194408ce5f16SSerge E. Hallyn return error; 194508ce5f16SSerge E. Hallyn 19461da177e4SLinus Torvalds error = security_inode_mknod(dir, dentry, mode, dev); 19471da177e4SLinus Torvalds if (error) 19481da177e4SLinus Torvalds return error; 19491da177e4SLinus Torvalds 19509e3509e2SJan Kara vfs_dq_init(dir); 19511da177e4SLinus Torvalds error = dir->i_op->mknod(dir, dentry, mode, dev); 1952a74574aaSStephen Smalley if (!error) 1953f38aa942SAmy Griffis fsnotify_create(dir, dentry); 19541da177e4SLinus Torvalds return error; 19551da177e4SLinus Torvalds } 19561da177e4SLinus Torvalds 1957463c3197SDave Hansen static int may_mknod(mode_t mode) 1958463c3197SDave Hansen { 1959463c3197SDave Hansen switch (mode & S_IFMT) { 1960463c3197SDave Hansen case S_IFREG: 1961463c3197SDave Hansen case S_IFCHR: 1962463c3197SDave Hansen case S_IFBLK: 1963463c3197SDave Hansen case S_IFIFO: 1964463c3197SDave Hansen case S_IFSOCK: 1965463c3197SDave Hansen case 0: /* zero mode translates to S_IFREG */ 1966463c3197SDave Hansen return 0; 1967463c3197SDave Hansen case S_IFDIR: 1968463c3197SDave Hansen return -EPERM; 1969463c3197SDave Hansen default: 1970463c3197SDave Hansen return -EINVAL; 1971463c3197SDave Hansen } 1972463c3197SDave Hansen } 1973463c3197SDave Hansen 19742e4d0924SHeiko Carstens SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, int, mode, 19752e4d0924SHeiko Carstens unsigned, dev) 19761da177e4SLinus Torvalds { 19772ad94ae6SAl Viro int error; 19781da177e4SLinus Torvalds char *tmp; 19791da177e4SLinus Torvalds struct dentry *dentry; 19801da177e4SLinus Torvalds struct nameidata nd; 19811da177e4SLinus Torvalds 19821da177e4SLinus Torvalds if (S_ISDIR(mode)) 19831da177e4SLinus Torvalds return -EPERM; 19841da177e4SLinus Torvalds 19852ad94ae6SAl Viro error = user_path_parent(dfd, filename, &nd, &tmp); 19861da177e4SLinus Torvalds if (error) 19872ad94ae6SAl Viro return error; 19882ad94ae6SAl Viro 19891da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 1990463c3197SDave Hansen if (IS_ERR(dentry)) { 19911da177e4SLinus Torvalds error = PTR_ERR(dentry); 1992463c3197SDave Hansen goto out_unlock; 1993463c3197SDave Hansen } 19944ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 1995ce3b0f8dSAl Viro mode &= ~current_umask(); 1996463c3197SDave Hansen error = may_mknod(mode); 1997463c3197SDave Hansen if (error) 1998463c3197SDave Hansen goto out_dput; 1999463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2000463c3197SDave Hansen if (error) 2001463c3197SDave Hansen goto out_dput; 2002be6d3e56SKentaro Takeda error = security_path_mknod(&nd.path, dentry, mode, dev); 2003be6d3e56SKentaro Takeda if (error) 2004be6d3e56SKentaro Takeda goto out_drop_write; 20051da177e4SLinus Torvalds switch (mode & S_IFMT) { 20061da177e4SLinus Torvalds case 0: case S_IFREG: 20074ac91378SJan Blunck error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); 20081da177e4SLinus Torvalds break; 20091da177e4SLinus Torvalds case S_IFCHR: case S_IFBLK: 20104ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, 20111da177e4SLinus Torvalds new_decode_dev(dev)); 20121da177e4SLinus Torvalds break; 20131da177e4SLinus Torvalds case S_IFIFO: case S_IFSOCK: 20144ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); 20151da177e4SLinus Torvalds break; 20161da177e4SLinus Torvalds } 2017be6d3e56SKentaro Takeda out_drop_write: 2018463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2019463c3197SDave Hansen out_dput: 20201da177e4SLinus Torvalds dput(dentry); 2021463c3197SDave Hansen out_unlock: 20224ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20231d957f9bSJan Blunck path_put(&nd.path); 20241da177e4SLinus Torvalds putname(tmp); 20251da177e4SLinus Torvalds 20261da177e4SLinus Torvalds return error; 20271da177e4SLinus Torvalds } 20281da177e4SLinus Torvalds 20293480b257SHeiko Carstens SYSCALL_DEFINE3(mknod, const char __user *, filename, int, mode, unsigned, dev) 20305590ff0dSUlrich Drepper { 20315590ff0dSUlrich Drepper return sys_mknodat(AT_FDCWD, filename, mode, dev); 20325590ff0dSUlrich Drepper } 20335590ff0dSUlrich Drepper 20341da177e4SLinus Torvalds int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 20351da177e4SLinus Torvalds { 2036a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 20371da177e4SLinus Torvalds 20381da177e4SLinus Torvalds if (error) 20391da177e4SLinus Torvalds return error; 20401da177e4SLinus Torvalds 2041acfa4380SAl Viro if (!dir->i_op->mkdir) 20421da177e4SLinus Torvalds return -EPERM; 20431da177e4SLinus Torvalds 20441da177e4SLinus Torvalds mode &= (S_IRWXUGO|S_ISVTX); 20451da177e4SLinus Torvalds error = security_inode_mkdir(dir, dentry, mode); 20461da177e4SLinus Torvalds if (error) 20471da177e4SLinus Torvalds return error; 20481da177e4SLinus Torvalds 20499e3509e2SJan Kara vfs_dq_init(dir); 20501da177e4SLinus Torvalds error = dir->i_op->mkdir(dir, dentry, mode); 2051a74574aaSStephen Smalley if (!error) 2052f38aa942SAmy Griffis fsnotify_mkdir(dir, dentry); 20531da177e4SLinus Torvalds return error; 20541da177e4SLinus Torvalds } 20551da177e4SLinus Torvalds 20562e4d0924SHeiko Carstens SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, int, mode) 20571da177e4SLinus Torvalds { 20581da177e4SLinus Torvalds int error = 0; 20591da177e4SLinus Torvalds char * tmp; 20606902d925SDave Hansen struct dentry *dentry; 20616902d925SDave Hansen struct nameidata nd; 20621da177e4SLinus Torvalds 20632ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &tmp); 20642ad94ae6SAl Viro if (error) 20656902d925SDave Hansen goto out_err; 20661da177e4SLinus Torvalds 20671da177e4SLinus Torvalds dentry = lookup_create(&nd, 1); 20681da177e4SLinus Torvalds error = PTR_ERR(dentry); 20696902d925SDave Hansen if (IS_ERR(dentry)) 20706902d925SDave Hansen goto out_unlock; 20716902d925SDave Hansen 20724ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 2073ce3b0f8dSAl Viro mode &= ~current_umask(); 2074463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2075463c3197SDave Hansen if (error) 2076463c3197SDave Hansen goto out_dput; 2077be6d3e56SKentaro Takeda error = security_path_mkdir(&nd.path, dentry, mode); 2078be6d3e56SKentaro Takeda if (error) 2079be6d3e56SKentaro Takeda goto out_drop_write; 20804ac91378SJan Blunck error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); 2081be6d3e56SKentaro Takeda out_drop_write: 2082463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2083463c3197SDave Hansen out_dput: 20841da177e4SLinus Torvalds dput(dentry); 20856902d925SDave Hansen out_unlock: 20864ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20871d957f9bSJan Blunck path_put(&nd.path); 20881da177e4SLinus Torvalds putname(tmp); 20896902d925SDave Hansen out_err: 20901da177e4SLinus Torvalds return error; 20911da177e4SLinus Torvalds } 20921da177e4SLinus Torvalds 20933cdad428SHeiko Carstens SYSCALL_DEFINE2(mkdir, const char __user *, pathname, int, mode) 20945590ff0dSUlrich Drepper { 20955590ff0dSUlrich Drepper return sys_mkdirat(AT_FDCWD, pathname, mode); 20965590ff0dSUlrich Drepper } 20975590ff0dSUlrich Drepper 20981da177e4SLinus Torvalds /* 20991da177e4SLinus Torvalds * We try to drop the dentry early: we should have 21001da177e4SLinus Torvalds * a usage count of 2 if we're the only user of this 21011da177e4SLinus Torvalds * dentry, and if that is true (possibly after pruning 21021da177e4SLinus Torvalds * the dcache), then we drop the dentry now. 21031da177e4SLinus Torvalds * 21041da177e4SLinus Torvalds * A low-level filesystem can, if it choses, legally 21051da177e4SLinus Torvalds * do a 21061da177e4SLinus Torvalds * 21071da177e4SLinus Torvalds * if (!d_unhashed(dentry)) 21081da177e4SLinus Torvalds * return -EBUSY; 21091da177e4SLinus Torvalds * 21101da177e4SLinus Torvalds * if it cannot handle the case of removing a directory 21111da177e4SLinus Torvalds * that is still in use by something else.. 21121da177e4SLinus Torvalds */ 21131da177e4SLinus Torvalds void dentry_unhash(struct dentry *dentry) 21141da177e4SLinus Torvalds { 21151da177e4SLinus Torvalds dget(dentry); 21161da177e4SLinus Torvalds shrink_dcache_parent(dentry); 21171da177e4SLinus Torvalds spin_lock(&dcache_lock); 21181da177e4SLinus Torvalds spin_lock(&dentry->d_lock); 21191da177e4SLinus Torvalds if (atomic_read(&dentry->d_count) == 2) 21201da177e4SLinus Torvalds __d_drop(dentry); 21211da177e4SLinus Torvalds spin_unlock(&dentry->d_lock); 21221da177e4SLinus Torvalds spin_unlock(&dcache_lock); 21231da177e4SLinus Torvalds } 21241da177e4SLinus Torvalds 21251da177e4SLinus Torvalds int vfs_rmdir(struct inode *dir, struct dentry *dentry) 21261da177e4SLinus Torvalds { 21271da177e4SLinus Torvalds int error = may_delete(dir, dentry, 1); 21281da177e4SLinus Torvalds 21291da177e4SLinus Torvalds if (error) 21301da177e4SLinus Torvalds return error; 21311da177e4SLinus Torvalds 2132acfa4380SAl Viro if (!dir->i_op->rmdir) 21331da177e4SLinus Torvalds return -EPERM; 21341da177e4SLinus Torvalds 21359e3509e2SJan Kara vfs_dq_init(dir); 21361da177e4SLinus Torvalds 21371b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 21381da177e4SLinus Torvalds dentry_unhash(dentry); 21391da177e4SLinus Torvalds if (d_mountpoint(dentry)) 21401da177e4SLinus Torvalds error = -EBUSY; 21411da177e4SLinus Torvalds else { 21421da177e4SLinus Torvalds error = security_inode_rmdir(dir, dentry); 21431da177e4SLinus Torvalds if (!error) { 21441da177e4SLinus Torvalds error = dir->i_op->rmdir(dir, dentry); 21451da177e4SLinus Torvalds if (!error) 21461da177e4SLinus Torvalds dentry->d_inode->i_flags |= S_DEAD; 21471da177e4SLinus Torvalds } 21481da177e4SLinus Torvalds } 21491b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 21501da177e4SLinus Torvalds if (!error) { 21511da177e4SLinus Torvalds d_delete(dentry); 21521da177e4SLinus Torvalds } 21531da177e4SLinus Torvalds dput(dentry); 21541da177e4SLinus Torvalds 21551da177e4SLinus Torvalds return error; 21561da177e4SLinus Torvalds } 21571da177e4SLinus Torvalds 21585590ff0dSUlrich Drepper static long do_rmdir(int dfd, const char __user *pathname) 21591da177e4SLinus Torvalds { 21601da177e4SLinus Torvalds int error = 0; 21611da177e4SLinus Torvalds char * name; 21621da177e4SLinus Torvalds struct dentry *dentry; 21631da177e4SLinus Torvalds struct nameidata nd; 21641da177e4SLinus Torvalds 21652ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 21661da177e4SLinus Torvalds if (error) 21672ad94ae6SAl Viro return error; 21681da177e4SLinus Torvalds 21691da177e4SLinus Torvalds switch(nd.last_type) { 21701da177e4SLinus Torvalds case LAST_DOTDOT: 21711da177e4SLinus Torvalds error = -ENOTEMPTY; 21721da177e4SLinus Torvalds goto exit1; 21731da177e4SLinus Torvalds case LAST_DOT: 21741da177e4SLinus Torvalds error = -EINVAL; 21751da177e4SLinus Torvalds goto exit1; 21761da177e4SLinus Torvalds case LAST_ROOT: 21771da177e4SLinus Torvalds error = -EBUSY; 21781da177e4SLinus Torvalds goto exit1; 21791da177e4SLinus Torvalds } 21800612d9fbSOGAWA Hirofumi 21810612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 21820612d9fbSOGAWA Hirofumi 21834ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 218449705b77SChristoph Hellwig dentry = lookup_hash(&nd); 21851da177e4SLinus Torvalds error = PTR_ERR(dentry); 21866902d925SDave Hansen if (IS_ERR(dentry)) 21876902d925SDave Hansen goto exit2; 21880622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 21890622753bSDave Hansen if (error) 21900622753bSDave Hansen goto exit3; 2191be6d3e56SKentaro Takeda error = security_path_rmdir(&nd.path, dentry); 2192be6d3e56SKentaro Takeda if (error) 2193be6d3e56SKentaro Takeda goto exit4; 21944ac91378SJan Blunck error = vfs_rmdir(nd.path.dentry->d_inode, dentry); 2195be6d3e56SKentaro Takeda exit4: 21960622753bSDave Hansen mnt_drop_write(nd.path.mnt); 21970622753bSDave Hansen exit3: 21981da177e4SLinus Torvalds dput(dentry); 21996902d925SDave Hansen exit2: 22004ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22011da177e4SLinus Torvalds exit1: 22021d957f9bSJan Blunck path_put(&nd.path); 22031da177e4SLinus Torvalds putname(name); 22041da177e4SLinus Torvalds return error; 22051da177e4SLinus Torvalds } 22061da177e4SLinus Torvalds 22073cdad428SHeiko Carstens SYSCALL_DEFINE1(rmdir, const char __user *, pathname) 22085590ff0dSUlrich Drepper { 22095590ff0dSUlrich Drepper return do_rmdir(AT_FDCWD, pathname); 22105590ff0dSUlrich Drepper } 22115590ff0dSUlrich Drepper 22121da177e4SLinus Torvalds int vfs_unlink(struct inode *dir, struct dentry *dentry) 22131da177e4SLinus Torvalds { 22141da177e4SLinus Torvalds int error = may_delete(dir, dentry, 0); 22151da177e4SLinus Torvalds 22161da177e4SLinus Torvalds if (error) 22171da177e4SLinus Torvalds return error; 22181da177e4SLinus Torvalds 2219acfa4380SAl Viro if (!dir->i_op->unlink) 22201da177e4SLinus Torvalds return -EPERM; 22211da177e4SLinus Torvalds 22229e3509e2SJan Kara vfs_dq_init(dir); 22231da177e4SLinus Torvalds 22241b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 22251da177e4SLinus Torvalds if (d_mountpoint(dentry)) 22261da177e4SLinus Torvalds error = -EBUSY; 22271da177e4SLinus Torvalds else { 22281da177e4SLinus Torvalds error = security_inode_unlink(dir, dentry); 22291da177e4SLinus Torvalds if (!error) 22301da177e4SLinus Torvalds error = dir->i_op->unlink(dir, dentry); 22311da177e4SLinus Torvalds } 22321b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 22331da177e4SLinus Torvalds 22341da177e4SLinus Torvalds /* We don't d_delete() NFS sillyrenamed files--they still exist. */ 22351da177e4SLinus Torvalds if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { 2236ece95912SJan Kara fsnotify_link_count(dentry->d_inode); 22371da177e4SLinus Torvalds d_delete(dentry); 22381da177e4SLinus Torvalds } 22390eeca283SRobert Love 22401da177e4SLinus Torvalds return error; 22411da177e4SLinus Torvalds } 22421da177e4SLinus Torvalds 22431da177e4SLinus Torvalds /* 22441da177e4SLinus Torvalds * Make sure that the actual truncation of the file will occur outside its 22451b1dcc1bSJes Sorensen * directory's i_mutex. Truncate can take a long time if there is a lot of 22461da177e4SLinus Torvalds * writeout happening, and we don't want to prevent access to the directory 22471da177e4SLinus Torvalds * while waiting on the I/O. 22481da177e4SLinus Torvalds */ 22495590ff0dSUlrich Drepper static long do_unlinkat(int dfd, const char __user *pathname) 22501da177e4SLinus Torvalds { 22512ad94ae6SAl Viro int error; 22521da177e4SLinus Torvalds char *name; 22531da177e4SLinus Torvalds struct dentry *dentry; 22541da177e4SLinus Torvalds struct nameidata nd; 22551da177e4SLinus Torvalds struct inode *inode = NULL; 22561da177e4SLinus Torvalds 22572ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 22581da177e4SLinus Torvalds if (error) 22592ad94ae6SAl Viro return error; 22602ad94ae6SAl Viro 22611da177e4SLinus Torvalds error = -EISDIR; 22621da177e4SLinus Torvalds if (nd.last_type != LAST_NORM) 22631da177e4SLinus Torvalds goto exit1; 22640612d9fbSOGAWA Hirofumi 22650612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 22660612d9fbSOGAWA Hirofumi 22674ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 226849705b77SChristoph Hellwig dentry = lookup_hash(&nd); 22691da177e4SLinus Torvalds error = PTR_ERR(dentry); 22701da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 22711da177e4SLinus Torvalds /* Why not before? Because we want correct error value */ 22721da177e4SLinus Torvalds if (nd.last.name[nd.last.len]) 22731da177e4SLinus Torvalds goto slashes; 22741da177e4SLinus Torvalds inode = dentry->d_inode; 22751da177e4SLinus Torvalds if (inode) 22761da177e4SLinus Torvalds atomic_inc(&inode->i_count); 22770622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 22780622753bSDave Hansen if (error) 22790622753bSDave Hansen goto exit2; 2280be6d3e56SKentaro Takeda error = security_path_unlink(&nd.path, dentry); 2281be6d3e56SKentaro Takeda if (error) 2282be6d3e56SKentaro Takeda goto exit3; 22834ac91378SJan Blunck error = vfs_unlink(nd.path.dentry->d_inode, dentry); 2284be6d3e56SKentaro Takeda exit3: 22850622753bSDave Hansen mnt_drop_write(nd.path.mnt); 22861da177e4SLinus Torvalds exit2: 22871da177e4SLinus Torvalds dput(dentry); 22881da177e4SLinus Torvalds } 22894ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22901da177e4SLinus Torvalds if (inode) 22911da177e4SLinus Torvalds iput(inode); /* truncate the inode here */ 22921da177e4SLinus Torvalds exit1: 22931d957f9bSJan Blunck path_put(&nd.path); 22941da177e4SLinus Torvalds putname(name); 22951da177e4SLinus Torvalds return error; 22961da177e4SLinus Torvalds 22971da177e4SLinus Torvalds slashes: 22981da177e4SLinus Torvalds error = !dentry->d_inode ? -ENOENT : 22991da177e4SLinus Torvalds S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; 23001da177e4SLinus Torvalds goto exit2; 23011da177e4SLinus Torvalds } 23021da177e4SLinus Torvalds 23032e4d0924SHeiko Carstens SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) 23045590ff0dSUlrich Drepper { 23055590ff0dSUlrich Drepper if ((flag & ~AT_REMOVEDIR) != 0) 23065590ff0dSUlrich Drepper return -EINVAL; 23075590ff0dSUlrich Drepper 23085590ff0dSUlrich Drepper if (flag & AT_REMOVEDIR) 23095590ff0dSUlrich Drepper return do_rmdir(dfd, pathname); 23105590ff0dSUlrich Drepper 23115590ff0dSUlrich Drepper return do_unlinkat(dfd, pathname); 23125590ff0dSUlrich Drepper } 23135590ff0dSUlrich Drepper 23143480b257SHeiko Carstens SYSCALL_DEFINE1(unlink, const char __user *, pathname) 23155590ff0dSUlrich Drepper { 23165590ff0dSUlrich Drepper return do_unlinkat(AT_FDCWD, pathname); 23175590ff0dSUlrich Drepper } 23185590ff0dSUlrich Drepper 2319db2e747bSMiklos Szeredi int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) 23201da177e4SLinus Torvalds { 2321a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 23221da177e4SLinus Torvalds 23231da177e4SLinus Torvalds if (error) 23241da177e4SLinus Torvalds return error; 23251da177e4SLinus Torvalds 2326acfa4380SAl Viro if (!dir->i_op->symlink) 23271da177e4SLinus Torvalds return -EPERM; 23281da177e4SLinus Torvalds 23291da177e4SLinus Torvalds error = security_inode_symlink(dir, dentry, oldname); 23301da177e4SLinus Torvalds if (error) 23311da177e4SLinus Torvalds return error; 23321da177e4SLinus Torvalds 23339e3509e2SJan Kara vfs_dq_init(dir); 23341da177e4SLinus Torvalds error = dir->i_op->symlink(dir, dentry, oldname); 2335a74574aaSStephen Smalley if (!error) 2336f38aa942SAmy Griffis fsnotify_create(dir, dentry); 23371da177e4SLinus Torvalds return error; 23381da177e4SLinus Torvalds } 23391da177e4SLinus Torvalds 23402e4d0924SHeiko Carstens SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, 23412e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 23421da177e4SLinus Torvalds { 23432ad94ae6SAl Viro int error; 23441da177e4SLinus Torvalds char *from; 23451da177e4SLinus Torvalds char *to; 23466902d925SDave Hansen struct dentry *dentry; 23476902d925SDave Hansen struct nameidata nd; 23481da177e4SLinus Torvalds 23491da177e4SLinus Torvalds from = getname(oldname); 23501da177e4SLinus Torvalds if (IS_ERR(from)) 23511da177e4SLinus Torvalds return PTR_ERR(from); 23522ad94ae6SAl Viro 23532ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 23542ad94ae6SAl Viro if (error) 23556902d925SDave Hansen goto out_putname; 23561da177e4SLinus Torvalds 23571da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 23581da177e4SLinus Torvalds error = PTR_ERR(dentry); 23596902d925SDave Hansen if (IS_ERR(dentry)) 23606902d925SDave Hansen goto out_unlock; 23616902d925SDave Hansen 236275c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 236375c3f29dSDave Hansen if (error) 236475c3f29dSDave Hansen goto out_dput; 2365be6d3e56SKentaro Takeda error = security_path_symlink(&nd.path, dentry, from); 2366be6d3e56SKentaro Takeda if (error) 2367be6d3e56SKentaro Takeda goto out_drop_write; 2368db2e747bSMiklos Szeredi error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); 2369be6d3e56SKentaro Takeda out_drop_write: 237075c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 237175c3f29dSDave Hansen out_dput: 23721da177e4SLinus Torvalds dput(dentry); 23736902d925SDave Hansen out_unlock: 23744ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 23751d957f9bSJan Blunck path_put(&nd.path); 23761da177e4SLinus Torvalds putname(to); 23776902d925SDave Hansen out_putname: 23781da177e4SLinus Torvalds putname(from); 23791da177e4SLinus Torvalds return error; 23801da177e4SLinus Torvalds } 23811da177e4SLinus Torvalds 23823480b257SHeiko Carstens SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) 23835590ff0dSUlrich Drepper { 23845590ff0dSUlrich Drepper return sys_symlinkat(oldname, AT_FDCWD, newname); 23855590ff0dSUlrich Drepper } 23865590ff0dSUlrich Drepper 23871da177e4SLinus Torvalds int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) 23881da177e4SLinus Torvalds { 23891da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 23901da177e4SLinus Torvalds int error; 23911da177e4SLinus Torvalds 23921da177e4SLinus Torvalds if (!inode) 23931da177e4SLinus Torvalds return -ENOENT; 23941da177e4SLinus Torvalds 2395a95164d9SMiklos Szeredi error = may_create(dir, new_dentry); 23961da177e4SLinus Torvalds if (error) 23971da177e4SLinus Torvalds return error; 23981da177e4SLinus Torvalds 23991da177e4SLinus Torvalds if (dir->i_sb != inode->i_sb) 24001da177e4SLinus Torvalds return -EXDEV; 24011da177e4SLinus Torvalds 24021da177e4SLinus Torvalds /* 24031da177e4SLinus Torvalds * A link to an append-only or immutable file cannot be created. 24041da177e4SLinus Torvalds */ 24051da177e4SLinus Torvalds if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) 24061da177e4SLinus Torvalds return -EPERM; 2407acfa4380SAl Viro if (!dir->i_op->link) 24081da177e4SLinus Torvalds return -EPERM; 24097e79eedbSTetsuo Handa if (S_ISDIR(inode->i_mode)) 24101da177e4SLinus Torvalds return -EPERM; 24111da177e4SLinus Torvalds 24121da177e4SLinus Torvalds error = security_inode_link(old_dentry, dir, new_dentry); 24131da177e4SLinus Torvalds if (error) 24141da177e4SLinus Torvalds return error; 24151da177e4SLinus Torvalds 24167e79eedbSTetsuo Handa mutex_lock(&inode->i_mutex); 24179e3509e2SJan Kara vfs_dq_init(dir); 24181da177e4SLinus Torvalds error = dir->i_op->link(old_dentry, dir, new_dentry); 24197e79eedbSTetsuo Handa mutex_unlock(&inode->i_mutex); 2420e31e14ecSStephen Smalley if (!error) 24217e79eedbSTetsuo Handa fsnotify_link(dir, inode, new_dentry); 24221da177e4SLinus Torvalds return error; 24231da177e4SLinus Torvalds } 24241da177e4SLinus Torvalds 24251da177e4SLinus Torvalds /* 24261da177e4SLinus Torvalds * Hardlinks are often used in delicate situations. We avoid 24271da177e4SLinus Torvalds * security-related surprises by not following symlinks on the 24281da177e4SLinus Torvalds * newname. --KAB 24291da177e4SLinus Torvalds * 24301da177e4SLinus Torvalds * We don't follow them on the oldname either to be compatible 24311da177e4SLinus Torvalds * with linux 2.0, and to avoid hard-linking to directories 24321da177e4SLinus Torvalds * and other special files. --ADM 24331da177e4SLinus Torvalds */ 24342e4d0924SHeiko Carstens SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, 24352e4d0924SHeiko Carstens int, newdfd, const char __user *, newname, int, flags) 24361da177e4SLinus Torvalds { 24371da177e4SLinus Torvalds struct dentry *new_dentry; 24382d8f3038SAl Viro struct nameidata nd; 24392d8f3038SAl Viro struct path old_path; 24401da177e4SLinus Torvalds int error; 24411da177e4SLinus Torvalds char *to; 24421da177e4SLinus Torvalds 244345c9b11aSUlrich Drepper if ((flags & ~AT_SYMLINK_FOLLOW) != 0) 2444c04030e1SUlrich Drepper return -EINVAL; 2445c04030e1SUlrich Drepper 24462d8f3038SAl Viro error = user_path_at(olddfd, oldname, 244745c9b11aSUlrich Drepper flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, 24482d8f3038SAl Viro &old_path); 24491da177e4SLinus Torvalds if (error) 24502ad94ae6SAl Viro return error; 24512ad94ae6SAl Viro 24522ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 24531da177e4SLinus Torvalds if (error) 24541da177e4SLinus Torvalds goto out; 24551da177e4SLinus Torvalds error = -EXDEV; 24562d8f3038SAl Viro if (old_path.mnt != nd.path.mnt) 24571da177e4SLinus Torvalds goto out_release; 24581da177e4SLinus Torvalds new_dentry = lookup_create(&nd, 0); 24591da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 24606902d925SDave Hansen if (IS_ERR(new_dentry)) 24616902d925SDave Hansen goto out_unlock; 246275c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 246375c3f29dSDave Hansen if (error) 246475c3f29dSDave Hansen goto out_dput; 2465be6d3e56SKentaro Takeda error = security_path_link(old_path.dentry, &nd.path, new_dentry); 2466be6d3e56SKentaro Takeda if (error) 2467be6d3e56SKentaro Takeda goto out_drop_write; 24682d8f3038SAl Viro error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); 2469be6d3e56SKentaro Takeda out_drop_write: 247075c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 247175c3f29dSDave Hansen out_dput: 24721da177e4SLinus Torvalds dput(new_dentry); 24736902d925SDave Hansen out_unlock: 24744ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 24751da177e4SLinus Torvalds out_release: 24761d957f9bSJan Blunck path_put(&nd.path); 24772ad94ae6SAl Viro putname(to); 24781da177e4SLinus Torvalds out: 24792d8f3038SAl Viro path_put(&old_path); 24801da177e4SLinus Torvalds 24811da177e4SLinus Torvalds return error; 24821da177e4SLinus Torvalds } 24831da177e4SLinus Torvalds 24843480b257SHeiko Carstens SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) 24855590ff0dSUlrich Drepper { 2486c04030e1SUlrich Drepper return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); 24875590ff0dSUlrich Drepper } 24885590ff0dSUlrich Drepper 24891da177e4SLinus Torvalds /* 24901da177e4SLinus Torvalds * The worst of all namespace operations - renaming directory. "Perverted" 24911da177e4SLinus Torvalds * doesn't even start to describe it. Somebody in UCB had a heck of a trip... 24921da177e4SLinus Torvalds * Problems: 24931da177e4SLinus Torvalds * a) we can get into loop creation. Check is done in is_subdir(). 24941da177e4SLinus Torvalds * b) race potential - two innocent renames can create a loop together. 24951da177e4SLinus Torvalds * That's where 4.4 screws up. Current fix: serialization on 2496a11f3a05SArjan van de Ven * sb->s_vfs_rename_mutex. We might be more accurate, but that's another 24971da177e4SLinus Torvalds * story. 24981da177e4SLinus Torvalds * c) we have to lock _three_ objects - parents and victim (if it exists). 24991b1dcc1bSJes Sorensen * And that - after we got ->i_mutex on parents (until then we don't know 25001da177e4SLinus Torvalds * whether the target exists). Solution: try to be smart with locking 25011da177e4SLinus Torvalds * order for inodes. We rely on the fact that tree topology may change 2502a11f3a05SArjan van de Ven * only under ->s_vfs_rename_mutex _and_ that parent of the object we 25031da177e4SLinus Torvalds * move will be locked. Thus we can rank directories by the tree 25041da177e4SLinus Torvalds * (ancestors first) and rank all non-directories after them. 25051da177e4SLinus Torvalds * That works since everybody except rename does "lock parent, lookup, 2506a11f3a05SArjan van de Ven * lock child" and rename is under ->s_vfs_rename_mutex. 25071da177e4SLinus Torvalds * HOWEVER, it relies on the assumption that any object with ->lookup() 25081da177e4SLinus Torvalds * has no more than 1 dentry. If "hybrid" objects will ever appear, 25091da177e4SLinus Torvalds * we'd better make sure that there's no link(2) for them. 25101da177e4SLinus Torvalds * d) some filesystems don't support opened-but-unlinked directories, 25111da177e4SLinus Torvalds * either because of layout or because they are not ready to deal with 25121da177e4SLinus Torvalds * all cases correctly. The latter will be fixed (taking this sort of 25131da177e4SLinus Torvalds * stuff into VFS), but the former is not going away. Solution: the same 25141da177e4SLinus Torvalds * trick as in rmdir(). 25151da177e4SLinus Torvalds * e) conversion from fhandle to dentry may come in the wrong moment - when 25161b1dcc1bSJes Sorensen * we are removing the target. Solution: we will have to grab ->i_mutex 25171da177e4SLinus Torvalds * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on 25181b1dcc1bSJes Sorensen * ->i_mutex on parents, which works but leads to some truely excessive 25191da177e4SLinus Torvalds * locking]. 25201da177e4SLinus Torvalds */ 252175c96f85SAdrian Bunk static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, 25221da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25231da177e4SLinus Torvalds { 25241da177e4SLinus Torvalds int error = 0; 25251da177e4SLinus Torvalds struct inode *target; 25261da177e4SLinus Torvalds 25271da177e4SLinus Torvalds /* 25281da177e4SLinus Torvalds * If we are going to change the parent - check write permissions, 25291da177e4SLinus Torvalds * we'll need to flip '..'. 25301da177e4SLinus Torvalds */ 25311da177e4SLinus Torvalds if (new_dir != old_dir) { 2532f419a2e3SAl Viro error = inode_permission(old_dentry->d_inode, MAY_WRITE); 25331da177e4SLinus Torvalds if (error) 25341da177e4SLinus Torvalds return error; 25351da177e4SLinus Torvalds } 25361da177e4SLinus Torvalds 25371da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25381da177e4SLinus Torvalds if (error) 25391da177e4SLinus Torvalds return error; 25401da177e4SLinus Torvalds 25411da177e4SLinus Torvalds target = new_dentry->d_inode; 25421da177e4SLinus Torvalds if (target) { 25431b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25441da177e4SLinus Torvalds dentry_unhash(new_dentry); 25451da177e4SLinus Torvalds } 25461da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25471da177e4SLinus Torvalds error = -EBUSY; 25481da177e4SLinus Torvalds else 25491da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25501da177e4SLinus Torvalds if (target) { 25511da177e4SLinus Torvalds if (!error) 25521da177e4SLinus Torvalds target->i_flags |= S_DEAD; 25531b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25541da177e4SLinus Torvalds if (d_unhashed(new_dentry)) 25551da177e4SLinus Torvalds d_rehash(new_dentry); 25561da177e4SLinus Torvalds dput(new_dentry); 25571da177e4SLinus Torvalds } 2558e31e14ecSStephen Smalley if (!error) 2559349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25601da177e4SLinus Torvalds d_move(old_dentry,new_dentry); 25611da177e4SLinus Torvalds return error; 25621da177e4SLinus Torvalds } 25631da177e4SLinus Torvalds 256475c96f85SAdrian Bunk static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, 25651da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25661da177e4SLinus Torvalds { 25671da177e4SLinus Torvalds struct inode *target; 25681da177e4SLinus Torvalds int error; 25691da177e4SLinus Torvalds 25701da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25711da177e4SLinus Torvalds if (error) 25721da177e4SLinus Torvalds return error; 25731da177e4SLinus Torvalds 25741da177e4SLinus Torvalds dget(new_dentry); 25751da177e4SLinus Torvalds target = new_dentry->d_inode; 25761da177e4SLinus Torvalds if (target) 25771b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25781da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25791da177e4SLinus Torvalds error = -EBUSY; 25801da177e4SLinus Torvalds else 25811da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25821da177e4SLinus Torvalds if (!error) { 2583349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25841da177e4SLinus Torvalds d_move(old_dentry, new_dentry); 25851da177e4SLinus Torvalds } 25861da177e4SLinus Torvalds if (target) 25871b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25881da177e4SLinus Torvalds dput(new_dentry); 25891da177e4SLinus Torvalds return error; 25901da177e4SLinus Torvalds } 25911da177e4SLinus Torvalds 25921da177e4SLinus Torvalds int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 25931da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25941da177e4SLinus Torvalds { 25951da177e4SLinus Torvalds int error; 25961da177e4SLinus Torvalds int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); 25970eeca283SRobert Love const char *old_name; 25981da177e4SLinus Torvalds 25991da177e4SLinus Torvalds if (old_dentry->d_inode == new_dentry->d_inode) 26001da177e4SLinus Torvalds return 0; 26011da177e4SLinus Torvalds 26021da177e4SLinus Torvalds error = may_delete(old_dir, old_dentry, is_dir); 26031da177e4SLinus Torvalds if (error) 26041da177e4SLinus Torvalds return error; 26051da177e4SLinus Torvalds 26061da177e4SLinus Torvalds if (!new_dentry->d_inode) 2607a95164d9SMiklos Szeredi error = may_create(new_dir, new_dentry); 26081da177e4SLinus Torvalds else 26091da177e4SLinus Torvalds error = may_delete(new_dir, new_dentry, is_dir); 26101da177e4SLinus Torvalds if (error) 26111da177e4SLinus Torvalds return error; 26121da177e4SLinus Torvalds 2613acfa4380SAl Viro if (!old_dir->i_op->rename) 26141da177e4SLinus Torvalds return -EPERM; 26151da177e4SLinus Torvalds 26169e3509e2SJan Kara vfs_dq_init(old_dir); 26179e3509e2SJan Kara vfs_dq_init(new_dir); 26181da177e4SLinus Torvalds 26190eeca283SRobert Love old_name = fsnotify_oldname_init(old_dentry->d_name.name); 26200eeca283SRobert Love 26211da177e4SLinus Torvalds if (is_dir) 26221da177e4SLinus Torvalds error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); 26231da177e4SLinus Torvalds else 26241da177e4SLinus Torvalds error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); 26251da177e4SLinus Torvalds if (!error) { 26260eeca283SRobert Love const char *new_name = old_dentry->d_name.name; 262789204c40SJohn McCutchan fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, 26285a190ae6SAl Viro new_dentry->d_inode, old_dentry); 26291da177e4SLinus Torvalds } 26300eeca283SRobert Love fsnotify_oldname_free(old_name); 26310eeca283SRobert Love 26321da177e4SLinus Torvalds return error; 26331da177e4SLinus Torvalds } 26341da177e4SLinus Torvalds 26352e4d0924SHeiko Carstens SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, 26362e4d0924SHeiko Carstens int, newdfd, const char __user *, newname) 26371da177e4SLinus Torvalds { 26381da177e4SLinus Torvalds struct dentry *old_dir, *new_dir; 26391da177e4SLinus Torvalds struct dentry *old_dentry, *new_dentry; 26401da177e4SLinus Torvalds struct dentry *trap; 26411da177e4SLinus Torvalds struct nameidata oldnd, newnd; 26422ad94ae6SAl Viro char *from; 26432ad94ae6SAl Viro char *to; 26442ad94ae6SAl Viro int error; 26451da177e4SLinus Torvalds 26462ad94ae6SAl Viro error = user_path_parent(olddfd, oldname, &oldnd, &from); 26471da177e4SLinus Torvalds if (error) 26481da177e4SLinus Torvalds goto exit; 26491da177e4SLinus Torvalds 26502ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &newnd, &to); 26511da177e4SLinus Torvalds if (error) 26521da177e4SLinus Torvalds goto exit1; 26531da177e4SLinus Torvalds 26541da177e4SLinus Torvalds error = -EXDEV; 26554ac91378SJan Blunck if (oldnd.path.mnt != newnd.path.mnt) 26561da177e4SLinus Torvalds goto exit2; 26571da177e4SLinus Torvalds 26584ac91378SJan Blunck old_dir = oldnd.path.dentry; 26591da177e4SLinus Torvalds error = -EBUSY; 26601da177e4SLinus Torvalds if (oldnd.last_type != LAST_NORM) 26611da177e4SLinus Torvalds goto exit2; 26621da177e4SLinus Torvalds 26634ac91378SJan Blunck new_dir = newnd.path.dentry; 26641da177e4SLinus Torvalds if (newnd.last_type != LAST_NORM) 26651da177e4SLinus Torvalds goto exit2; 26661da177e4SLinus Torvalds 26670612d9fbSOGAWA Hirofumi oldnd.flags &= ~LOOKUP_PARENT; 26680612d9fbSOGAWA Hirofumi newnd.flags &= ~LOOKUP_PARENT; 26694e9ed2f8SOGAWA Hirofumi newnd.flags |= LOOKUP_RENAME_TARGET; 26700612d9fbSOGAWA Hirofumi 26711da177e4SLinus Torvalds trap = lock_rename(new_dir, old_dir); 26721da177e4SLinus Torvalds 267349705b77SChristoph Hellwig old_dentry = lookup_hash(&oldnd); 26741da177e4SLinus Torvalds error = PTR_ERR(old_dentry); 26751da177e4SLinus Torvalds if (IS_ERR(old_dentry)) 26761da177e4SLinus Torvalds goto exit3; 26771da177e4SLinus Torvalds /* source must exist */ 26781da177e4SLinus Torvalds error = -ENOENT; 26791da177e4SLinus Torvalds if (!old_dentry->d_inode) 26801da177e4SLinus Torvalds goto exit4; 26811da177e4SLinus Torvalds /* unless the source is a directory trailing slashes give -ENOTDIR */ 26821da177e4SLinus Torvalds if (!S_ISDIR(old_dentry->d_inode->i_mode)) { 26831da177e4SLinus Torvalds error = -ENOTDIR; 26841da177e4SLinus Torvalds if (oldnd.last.name[oldnd.last.len]) 26851da177e4SLinus Torvalds goto exit4; 26861da177e4SLinus Torvalds if (newnd.last.name[newnd.last.len]) 26871da177e4SLinus Torvalds goto exit4; 26881da177e4SLinus Torvalds } 26891da177e4SLinus Torvalds /* source should not be ancestor of target */ 26901da177e4SLinus Torvalds error = -EINVAL; 26911da177e4SLinus Torvalds if (old_dentry == trap) 26921da177e4SLinus Torvalds goto exit4; 269349705b77SChristoph Hellwig new_dentry = lookup_hash(&newnd); 26941da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 26951da177e4SLinus Torvalds if (IS_ERR(new_dentry)) 26961da177e4SLinus Torvalds goto exit4; 26971da177e4SLinus Torvalds /* target should not be an ancestor of source */ 26981da177e4SLinus Torvalds error = -ENOTEMPTY; 26991da177e4SLinus Torvalds if (new_dentry == trap) 27001da177e4SLinus Torvalds goto exit5; 27011da177e4SLinus Torvalds 27029079b1ebSDave Hansen error = mnt_want_write(oldnd.path.mnt); 27039079b1ebSDave Hansen if (error) 27049079b1ebSDave Hansen goto exit5; 2705be6d3e56SKentaro Takeda error = security_path_rename(&oldnd.path, old_dentry, 2706be6d3e56SKentaro Takeda &newnd.path, new_dentry); 2707be6d3e56SKentaro Takeda if (error) 2708be6d3e56SKentaro Takeda goto exit6; 27091da177e4SLinus Torvalds error = vfs_rename(old_dir->d_inode, old_dentry, 27101da177e4SLinus Torvalds new_dir->d_inode, new_dentry); 2711be6d3e56SKentaro Takeda exit6: 27129079b1ebSDave Hansen mnt_drop_write(oldnd.path.mnt); 27131da177e4SLinus Torvalds exit5: 27141da177e4SLinus Torvalds dput(new_dentry); 27151da177e4SLinus Torvalds exit4: 27161da177e4SLinus Torvalds dput(old_dentry); 27171da177e4SLinus Torvalds exit3: 27181da177e4SLinus Torvalds unlock_rename(new_dir, old_dir); 27191da177e4SLinus Torvalds exit2: 27201d957f9bSJan Blunck path_put(&newnd.path); 27212ad94ae6SAl Viro putname(to); 27221da177e4SLinus Torvalds exit1: 27231d957f9bSJan Blunck path_put(&oldnd.path); 27241da177e4SLinus Torvalds putname(from); 27252ad94ae6SAl Viro exit: 27261da177e4SLinus Torvalds return error; 27271da177e4SLinus Torvalds } 27281da177e4SLinus Torvalds 2729a26eab24SHeiko Carstens SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) 27305590ff0dSUlrich Drepper { 27315590ff0dSUlrich Drepper return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); 27325590ff0dSUlrich Drepper } 27335590ff0dSUlrich Drepper 27341da177e4SLinus Torvalds int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) 27351da177e4SLinus Torvalds { 27361da177e4SLinus Torvalds int len; 27371da177e4SLinus Torvalds 27381da177e4SLinus Torvalds len = PTR_ERR(link); 27391da177e4SLinus Torvalds if (IS_ERR(link)) 27401da177e4SLinus Torvalds goto out; 27411da177e4SLinus Torvalds 27421da177e4SLinus Torvalds len = strlen(link); 27431da177e4SLinus Torvalds if (len > (unsigned) buflen) 27441da177e4SLinus Torvalds len = buflen; 27451da177e4SLinus Torvalds if (copy_to_user(buffer, link, len)) 27461da177e4SLinus Torvalds len = -EFAULT; 27471da177e4SLinus Torvalds out: 27481da177e4SLinus Torvalds return len; 27491da177e4SLinus Torvalds } 27501da177e4SLinus Torvalds 27511da177e4SLinus Torvalds /* 27521da177e4SLinus Torvalds * A helper for ->readlink(). This should be used *ONLY* for symlinks that 27531da177e4SLinus Torvalds * have ->follow_link() touching nd only in nd_set_link(). Using (or not 27541da177e4SLinus Torvalds * using) it for any given inode is up to filesystem. 27551da177e4SLinus Torvalds */ 27561da177e4SLinus Torvalds int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27571da177e4SLinus Torvalds { 27581da177e4SLinus Torvalds struct nameidata nd; 2759cc314eefSLinus Torvalds void *cookie; 2760694a1764SMarcin Slusarz int res; 2761cc314eefSLinus Torvalds 27621da177e4SLinus Torvalds nd.depth = 0; 2763cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); 2764694a1764SMarcin Slusarz if (IS_ERR(cookie)) 2765694a1764SMarcin Slusarz return PTR_ERR(cookie); 2766694a1764SMarcin Slusarz 2767694a1764SMarcin Slusarz res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); 27681da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 2769cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, &nd, cookie); 2770694a1764SMarcin Slusarz return res; 27711da177e4SLinus Torvalds } 27721da177e4SLinus Torvalds 27731da177e4SLinus Torvalds int vfs_follow_link(struct nameidata *nd, const char *link) 27741da177e4SLinus Torvalds { 27751da177e4SLinus Torvalds return __vfs_follow_link(nd, link); 27761da177e4SLinus Torvalds } 27771da177e4SLinus Torvalds 27781da177e4SLinus Torvalds /* get the link contents into pagecache */ 27791da177e4SLinus Torvalds static char *page_getlink(struct dentry * dentry, struct page **ppage) 27801da177e4SLinus Torvalds { 2781ebd09abbSDuane Griffin char *kaddr; 27821da177e4SLinus Torvalds struct page *page; 27831da177e4SLinus Torvalds struct address_space *mapping = dentry->d_inode->i_mapping; 2784090d2b18SPekka Enberg page = read_mapping_page(mapping, 0, NULL); 27851da177e4SLinus Torvalds if (IS_ERR(page)) 27866fe6900eSNick Piggin return (char*)page; 27871da177e4SLinus Torvalds *ppage = page; 2788ebd09abbSDuane Griffin kaddr = kmap(page); 2789ebd09abbSDuane Griffin nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); 2790ebd09abbSDuane Griffin return kaddr; 27911da177e4SLinus Torvalds } 27921da177e4SLinus Torvalds 27931da177e4SLinus Torvalds int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27941da177e4SLinus Torvalds { 27951da177e4SLinus Torvalds struct page *page = NULL; 27961da177e4SLinus Torvalds char *s = page_getlink(dentry, &page); 27971da177e4SLinus Torvalds int res = vfs_readlink(dentry,buffer,buflen,s); 27981da177e4SLinus Torvalds if (page) { 27991da177e4SLinus Torvalds kunmap(page); 28001da177e4SLinus Torvalds page_cache_release(page); 28011da177e4SLinus Torvalds } 28021da177e4SLinus Torvalds return res; 28031da177e4SLinus Torvalds } 28041da177e4SLinus Torvalds 2805cc314eefSLinus Torvalds void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) 28061da177e4SLinus Torvalds { 2807cc314eefSLinus Torvalds struct page *page = NULL; 28081da177e4SLinus Torvalds nd_set_link(nd, page_getlink(dentry, &page)); 2809cc314eefSLinus Torvalds return page; 28101da177e4SLinus Torvalds } 28111da177e4SLinus Torvalds 2812cc314eefSLinus Torvalds void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 28131da177e4SLinus Torvalds { 2814cc314eefSLinus Torvalds struct page *page = cookie; 2815cc314eefSLinus Torvalds 2816cc314eefSLinus Torvalds if (page) { 28171da177e4SLinus Torvalds kunmap(page); 28181da177e4SLinus Torvalds page_cache_release(page); 28191da177e4SLinus Torvalds } 28201da177e4SLinus Torvalds } 28211da177e4SLinus Torvalds 282254566b2cSNick Piggin /* 282354566b2cSNick Piggin * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS 282454566b2cSNick Piggin */ 282554566b2cSNick Piggin int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) 28261da177e4SLinus Torvalds { 28271da177e4SLinus Torvalds struct address_space *mapping = inode->i_mapping; 28280adb25d2SKirill Korotaev struct page *page; 2829afddba49SNick Piggin void *fsdata; 2830beb497abSDmitriy Monakhov int err; 28311da177e4SLinus Torvalds char *kaddr; 283254566b2cSNick Piggin unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; 283354566b2cSNick Piggin if (nofs) 283454566b2cSNick Piggin flags |= AOP_FLAG_NOFS; 28351da177e4SLinus Torvalds 28367e53cac4SNeilBrown retry: 2837afddba49SNick Piggin err = pagecache_write_begin(NULL, mapping, 0, len-1, 283854566b2cSNick Piggin flags, &page, &fsdata); 28391da177e4SLinus Torvalds if (err) 2840afddba49SNick Piggin goto fail; 2841afddba49SNick Piggin 28421da177e4SLinus Torvalds kaddr = kmap_atomic(page, KM_USER0); 28431da177e4SLinus Torvalds memcpy(kaddr, symname, len-1); 28441da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 2845afddba49SNick Piggin 2846afddba49SNick Piggin err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, 2847afddba49SNick Piggin page, fsdata); 28481da177e4SLinus Torvalds if (err < 0) 28491da177e4SLinus Torvalds goto fail; 2850afddba49SNick Piggin if (err < len-1) 2851afddba49SNick Piggin goto retry; 2852afddba49SNick Piggin 28531da177e4SLinus Torvalds mark_inode_dirty(inode); 28541da177e4SLinus Torvalds return 0; 28551da177e4SLinus Torvalds fail: 28561da177e4SLinus Torvalds return err; 28571da177e4SLinus Torvalds } 28581da177e4SLinus Torvalds 28590adb25d2SKirill Korotaev int page_symlink(struct inode *inode, const char *symname, int len) 28600adb25d2SKirill Korotaev { 28610adb25d2SKirill Korotaev return __page_symlink(inode, symname, len, 286254566b2cSNick Piggin !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); 28630adb25d2SKirill Korotaev } 28640adb25d2SKirill Korotaev 286592e1d5beSArjan van de Ven const struct inode_operations page_symlink_inode_operations = { 28661da177e4SLinus Torvalds .readlink = generic_readlink, 28671da177e4SLinus Torvalds .follow_link = page_follow_link_light, 28681da177e4SLinus Torvalds .put_link = page_put_link, 28691da177e4SLinus Torvalds }; 28701da177e4SLinus Torvalds 28712d8f3038SAl Viro EXPORT_SYMBOL(user_path_at); 28721da177e4SLinus Torvalds EXPORT_SYMBOL(follow_down); 28731da177e4SLinus Torvalds EXPORT_SYMBOL(follow_up); 28741da177e4SLinus Torvalds EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ 28751da177e4SLinus Torvalds EXPORT_SYMBOL(getname); 28761da177e4SLinus Torvalds EXPORT_SYMBOL(lock_rename); 28771da177e4SLinus Torvalds EXPORT_SYMBOL(lookup_one_len); 28781da177e4SLinus Torvalds EXPORT_SYMBOL(page_follow_link_light); 28791da177e4SLinus Torvalds EXPORT_SYMBOL(page_put_link); 28801da177e4SLinus Torvalds EXPORT_SYMBOL(page_readlink); 28810adb25d2SKirill Korotaev EXPORT_SYMBOL(__page_symlink); 28821da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink); 28831da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink_inode_operations); 28841da177e4SLinus Torvalds EXPORT_SYMBOL(path_lookup); 2885d1811465SAl Viro EXPORT_SYMBOL(kern_path); 288616f18200SJosef 'Jeff' Sipek EXPORT_SYMBOL(vfs_path_lookup); 2887f419a2e3SAl Viro EXPORT_SYMBOL(inode_permission); 28888c744fb8SChristoph Hellwig EXPORT_SYMBOL(file_permission); 28891da177e4SLinus Torvalds EXPORT_SYMBOL(unlock_rename); 28901da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_create); 28911da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_follow_link); 28921da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_link); 28931da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mkdir); 28941da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mknod); 28951da177e4SLinus Torvalds EXPORT_SYMBOL(generic_permission); 28961da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_readlink); 28971da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rename); 28981da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rmdir); 28991da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_symlink); 29001da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_unlink); 29011da177e4SLinus Torvalds EXPORT_SYMBOL(dentry_unhash); 29021da177e4SLinus Torvalds EXPORT_SYMBOL(generic_readlink); 2903