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> 271da177e4SLinus Torvalds #include <linux/syscalls.h> 281da177e4SLinus Torvalds #include <linux/mount.h> 291da177e4SLinus Torvalds #include <linux/audit.h> 3016f7e0feSRandy Dunlap #include <linux/capability.h> 31834f2a4aSTrond Myklebust #include <linux/file.h> 325590ff0dSUlrich Drepper #include <linux/fcntl.h> 3308ce5f16SSerge E. Hallyn #include <linux/device_cgroup.h> 341da177e4SLinus Torvalds #include <asm/uaccess.h> 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds #define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE]) 371da177e4SLinus Torvalds 381da177e4SLinus Torvalds /* [Feb-1997 T. Schoebel-Theuer] 391da177e4SLinus Torvalds * Fundamental changes in the pathname lookup mechanisms (namei) 401da177e4SLinus Torvalds * were necessary because of omirr. The reason is that omirr needs 411da177e4SLinus Torvalds * to know the _real_ pathname, not the user-supplied one, in case 421da177e4SLinus Torvalds * of symlinks (and also when transname replacements occur). 431da177e4SLinus Torvalds * 441da177e4SLinus Torvalds * The new code replaces the old recursive symlink resolution with 451da177e4SLinus Torvalds * an iterative one (in case of non-nested symlink chains). It does 461da177e4SLinus Torvalds * this with calls to <fs>_follow_link(). 471da177e4SLinus Torvalds * As a side effect, dir_namei(), _namei() and follow_link() are now 481da177e4SLinus Torvalds * replaced with a single function lookup_dentry() that can handle all 491da177e4SLinus Torvalds * the special cases of the former code. 501da177e4SLinus Torvalds * 511da177e4SLinus Torvalds * With the new dcache, the pathname is stored at each inode, at least as 521da177e4SLinus Torvalds * long as the refcount of the inode is positive. As a side effect, the 531da177e4SLinus Torvalds * size of the dcache depends on the inode cache and thus is dynamic. 541da177e4SLinus Torvalds * 551da177e4SLinus Torvalds * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink 561da177e4SLinus Torvalds * resolution to correspond with current state of the code. 571da177e4SLinus Torvalds * 581da177e4SLinus Torvalds * Note that the symlink resolution is not *completely* iterative. 591da177e4SLinus Torvalds * There is still a significant amount of tail- and mid- recursion in 601da177e4SLinus Torvalds * the algorithm. Also, note that <fs>_readlink() is not used in 611da177e4SLinus Torvalds * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() 621da177e4SLinus Torvalds * may return different results than <fs>_follow_link(). Many virtual 631da177e4SLinus Torvalds * filesystems (including /proc) exhibit this behavior. 641da177e4SLinus Torvalds */ 651da177e4SLinus Torvalds 661da177e4SLinus Torvalds /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: 671da177e4SLinus Torvalds * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL 681da177e4SLinus Torvalds * and the name already exists in form of a symlink, try to create the new 691da177e4SLinus Torvalds * name indicated by the symlink. The old code always complained that the 701da177e4SLinus Torvalds * name already exists, due to not following the symlink even if its target 711da177e4SLinus Torvalds * is nonexistent. The new semantics affects also mknod() and link() when 721da177e4SLinus Torvalds * the name is a symlink pointing to a non-existant name. 731da177e4SLinus Torvalds * 741da177e4SLinus Torvalds * I don't know which semantics is the right one, since I have no access 751da177e4SLinus Torvalds * to standards. But I found by trial that HP-UX 9.0 has the full "new" 761da177e4SLinus Torvalds * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the 771da177e4SLinus Torvalds * "old" one. Personally, I think the new semantics is much more logical. 781da177e4SLinus Torvalds * Note that "ln old new" where "new" is a symlink pointing to a non-existing 791da177e4SLinus Torvalds * file does succeed in both HP-UX and SunOs, but not in Solaris 801da177e4SLinus Torvalds * and in the old Linux semantics. 811da177e4SLinus Torvalds */ 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink 841da177e4SLinus Torvalds * semantics. See the comments in "open_namei" and "do_link" below. 851da177e4SLinus Torvalds * 861da177e4SLinus Torvalds * [10-Sep-98 Alan Modra] Another symlink change. 871da177e4SLinus Torvalds */ 881da177e4SLinus Torvalds 891da177e4SLinus Torvalds /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: 901da177e4SLinus Torvalds * inside the path - always follow. 911da177e4SLinus Torvalds * in the last component in creation/removal/renaming - never follow. 921da177e4SLinus Torvalds * if LOOKUP_FOLLOW passed - follow. 931da177e4SLinus Torvalds * if the pathname has trailing slashes - follow. 941da177e4SLinus Torvalds * otherwise - don't follow. 951da177e4SLinus Torvalds * (applied in that order). 961da177e4SLinus Torvalds * 971da177e4SLinus Torvalds * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT 981da177e4SLinus Torvalds * restored for 2.4. This is the last surviving part of old 4.2BSD bug. 991da177e4SLinus Torvalds * During the 2.4 we need to fix the userland stuff depending on it - 1001da177e4SLinus Torvalds * hopefully we will be able to get rid of that wart in 2.5. So far only 1011da177e4SLinus Torvalds * XEmacs seems to be relying on it... 1021da177e4SLinus Torvalds */ 1031da177e4SLinus Torvalds /* 1041da177e4SLinus Torvalds * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) 105a11f3a05SArjan van de Ven * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives 1061da177e4SLinus Torvalds * any extra contention... 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds 109a02f76c3SAl Viro static int __link_path_walk(const char *name, struct nameidata *nd); 110c4a7808fSJosef 'Jeff' Sipek 1111da177e4SLinus Torvalds /* In order to reduce some races, while at the same time doing additional 1121da177e4SLinus Torvalds * checking and hopefully speeding things up, we copy filenames to the 1131da177e4SLinus Torvalds * kernel data space before using them.. 1141da177e4SLinus Torvalds * 1151da177e4SLinus Torvalds * POSIX.1 2.4: an empty pathname is invalid (ENOENT). 1161da177e4SLinus Torvalds * PATH_MAX includes the nul terminator --RR. 1171da177e4SLinus Torvalds */ 118858119e1SArjan van de Ven static int do_getname(const char __user *filename, char *page) 1191da177e4SLinus Torvalds { 1201da177e4SLinus Torvalds int retval; 1211da177e4SLinus Torvalds unsigned long len = PATH_MAX; 1221da177e4SLinus Torvalds 1231da177e4SLinus Torvalds if (!segment_eq(get_fs(), KERNEL_DS)) { 1241da177e4SLinus Torvalds if ((unsigned long) filename >= TASK_SIZE) 1251da177e4SLinus Torvalds return -EFAULT; 1261da177e4SLinus Torvalds if (TASK_SIZE - (unsigned long) filename < PATH_MAX) 1271da177e4SLinus Torvalds len = TASK_SIZE - (unsigned long) filename; 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds 1301da177e4SLinus Torvalds retval = strncpy_from_user(page, filename, len); 1311da177e4SLinus Torvalds if (retval > 0) { 1321da177e4SLinus Torvalds if (retval < len) 1331da177e4SLinus Torvalds return 0; 1341da177e4SLinus Torvalds return -ENAMETOOLONG; 1351da177e4SLinus Torvalds } else if (!retval) 1361da177e4SLinus Torvalds retval = -ENOENT; 1371da177e4SLinus Torvalds return retval; 1381da177e4SLinus Torvalds } 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds char * getname(const char __user * filename) 1411da177e4SLinus Torvalds { 1421da177e4SLinus Torvalds char *tmp, *result; 1431da177e4SLinus Torvalds 1441da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 1451da177e4SLinus Torvalds tmp = __getname(); 1461da177e4SLinus Torvalds if (tmp) { 1471da177e4SLinus Torvalds int retval = do_getname(filename, tmp); 1481da177e4SLinus Torvalds 1491da177e4SLinus Torvalds result = tmp; 1501da177e4SLinus Torvalds if (retval < 0) { 1511da177e4SLinus Torvalds __putname(tmp); 1521da177e4SLinus Torvalds result = ERR_PTR(retval); 1531da177e4SLinus Torvalds } 1541da177e4SLinus Torvalds } 1551da177e4SLinus Torvalds audit_getname(result); 1561da177e4SLinus Torvalds return result; 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds 1591da177e4SLinus Torvalds #ifdef CONFIG_AUDITSYSCALL 1601da177e4SLinus Torvalds void putname(const char *name) 1611da177e4SLinus Torvalds { 1625ac3a9c2SAl Viro if (unlikely(!audit_dummy_context())) 1631da177e4SLinus Torvalds audit_putname(name); 1641da177e4SLinus Torvalds else 1651da177e4SLinus Torvalds __putname(name); 1661da177e4SLinus Torvalds } 1671da177e4SLinus Torvalds EXPORT_SYMBOL(putname); 1681da177e4SLinus Torvalds #endif 1691da177e4SLinus Torvalds 1701da177e4SLinus Torvalds 1711da177e4SLinus Torvalds /** 1721da177e4SLinus Torvalds * generic_permission - check for access rights on a Posix-like filesystem 1731da177e4SLinus Torvalds * @inode: inode to check access rights for 1741da177e4SLinus Torvalds * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 1751da177e4SLinus Torvalds * @check_acl: optional callback to check for Posix ACLs 1761da177e4SLinus Torvalds * 1771da177e4SLinus Torvalds * Used to check for read/write/execute permissions on a file. 1781da177e4SLinus Torvalds * We use "fsuid" for this, letting us set arbitrary permissions 1791da177e4SLinus Torvalds * for filesystem access without changing the "normal" uids which 1801da177e4SLinus Torvalds * are used for other things.. 1811da177e4SLinus Torvalds */ 1821da177e4SLinus Torvalds int generic_permission(struct inode *inode, int mask, 1831da177e4SLinus Torvalds int (*check_acl)(struct inode *inode, int mask)) 1841da177e4SLinus Torvalds { 1851da177e4SLinus Torvalds umode_t mode = inode->i_mode; 1861da177e4SLinus Torvalds 187e6305c43SAl Viro mask &= MAY_READ | MAY_WRITE | MAY_EXEC; 188e6305c43SAl Viro 189da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 1901da177e4SLinus Torvalds mode >>= 6; 1911da177e4SLinus Torvalds else { 1921da177e4SLinus Torvalds if (IS_POSIXACL(inode) && (mode & S_IRWXG) && check_acl) { 1931da177e4SLinus Torvalds int error = check_acl(inode, mask); 1941da177e4SLinus Torvalds if (error == -EACCES) 1951da177e4SLinus Torvalds goto check_capabilities; 1961da177e4SLinus Torvalds else if (error != -EAGAIN) 1971da177e4SLinus Torvalds return error; 1981da177e4SLinus Torvalds } 1991da177e4SLinus Torvalds 2001da177e4SLinus Torvalds if (in_group_p(inode->i_gid)) 2011da177e4SLinus Torvalds mode >>= 3; 2021da177e4SLinus Torvalds } 2031da177e4SLinus Torvalds 2041da177e4SLinus Torvalds /* 2051da177e4SLinus Torvalds * If the DACs are ok we don't need any capability check. 2061da177e4SLinus Torvalds */ 207e6305c43SAl Viro if ((mask & ~mode) == 0) 2081da177e4SLinus Torvalds return 0; 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds check_capabilities: 2111da177e4SLinus Torvalds /* 2121da177e4SLinus Torvalds * Read/write DACs are always overridable. 2131da177e4SLinus Torvalds * Executable DACs are overridable if at least one exec bit is set. 2141da177e4SLinus Torvalds */ 215f696a365SMiklos Szeredi if (!(mask & MAY_EXEC) || execute_ok(inode)) 2161da177e4SLinus Torvalds if (capable(CAP_DAC_OVERRIDE)) 2171da177e4SLinus Torvalds return 0; 2181da177e4SLinus Torvalds 2191da177e4SLinus Torvalds /* 2201da177e4SLinus Torvalds * Searching includes executable on directories, else just read. 2211da177e4SLinus Torvalds */ 2221da177e4SLinus Torvalds if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) 2231da177e4SLinus Torvalds if (capable(CAP_DAC_READ_SEARCH)) 2241da177e4SLinus Torvalds return 0; 2251da177e4SLinus Torvalds 2261da177e4SLinus Torvalds return -EACCES; 2271da177e4SLinus Torvalds } 2281da177e4SLinus Torvalds 229f419a2e3SAl Viro int inode_permission(struct inode *inode, int mask) 2301da177e4SLinus Torvalds { 231e6305c43SAl Viro int retval; 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds if (mask & MAY_WRITE) { 23422590e41SMiklos Szeredi umode_t mode = inode->i_mode; 2351da177e4SLinus Torvalds 2361da177e4SLinus Torvalds /* 2371da177e4SLinus Torvalds * Nobody gets write access to a read-only fs. 2381da177e4SLinus Torvalds */ 2391da177e4SLinus Torvalds if (IS_RDONLY(inode) && 2401da177e4SLinus Torvalds (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) 2411da177e4SLinus Torvalds return -EROFS; 2421da177e4SLinus Torvalds 2431da177e4SLinus Torvalds /* 2441da177e4SLinus Torvalds * Nobody gets write access to an immutable file. 2451da177e4SLinus Torvalds */ 2461da177e4SLinus Torvalds if (IS_IMMUTABLE(inode)) 2471da177e4SLinus Torvalds return -EACCES; 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds 250f696a365SMiklos Szeredi if (inode->i_op && inode->i_op->permission) 251b77b0646SAl Viro retval = inode->i_op->permission(inode, mask); 252f696a365SMiklos Szeredi else 253e6305c43SAl Viro retval = generic_permission(inode, mask, NULL); 254f696a365SMiklos Szeredi 2551da177e4SLinus Torvalds if (retval) 2561da177e4SLinus Torvalds return retval; 2571da177e4SLinus Torvalds 25808ce5f16SSerge E. Hallyn retval = devcgroup_inode_permission(inode, mask); 25908ce5f16SSerge E. Hallyn if (retval) 26008ce5f16SSerge E. Hallyn return retval; 26108ce5f16SSerge E. Hallyn 262e6305c43SAl Viro return security_inode_permission(inode, 263f418b006SStephen Smalley mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND)); 2641da177e4SLinus Torvalds } 2651da177e4SLinus Torvalds 266e4543eddSChristoph Hellwig /** 267e4543eddSChristoph Hellwig * vfs_permission - check for access rights to a given path 268e4543eddSChristoph Hellwig * @nd: lookup result that describes the path 269e4543eddSChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 270e4543eddSChristoph Hellwig * 271e4543eddSChristoph Hellwig * Used to check for read/write/execute permissions on a path. 272e4543eddSChristoph Hellwig * We use "fsuid" for this, letting us set arbitrary permissions 273e4543eddSChristoph Hellwig * for filesystem access without changing the "normal" uids which 274e4543eddSChristoph Hellwig * are used for other things. 275e4543eddSChristoph Hellwig */ 276e4543eddSChristoph Hellwig int vfs_permission(struct nameidata *nd, int mask) 277e4543eddSChristoph Hellwig { 278f419a2e3SAl Viro return inode_permission(nd->path.dentry->d_inode, mask); 279e4543eddSChristoph Hellwig } 280e4543eddSChristoph Hellwig 2818c744fb8SChristoph Hellwig /** 2828c744fb8SChristoph Hellwig * file_permission - check for additional access rights to a given file 2838c744fb8SChristoph Hellwig * @file: file to check access rights for 2848c744fb8SChristoph Hellwig * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) 2858c744fb8SChristoph Hellwig * 2868c744fb8SChristoph Hellwig * Used to check for read/write/execute permissions on an already opened 2878c744fb8SChristoph Hellwig * file. 2888c744fb8SChristoph Hellwig * 2898c744fb8SChristoph Hellwig * Note: 2908c744fb8SChristoph Hellwig * Do not use this function in new code. All access checks should 2918c744fb8SChristoph Hellwig * be done using vfs_permission(). 2928c744fb8SChristoph Hellwig */ 2938c744fb8SChristoph Hellwig int file_permission(struct file *file, int mask) 2948c744fb8SChristoph Hellwig { 295f419a2e3SAl Viro return inode_permission(file->f_path.dentry->d_inode, mask); 2968c744fb8SChristoph Hellwig } 2978c744fb8SChristoph Hellwig 2981da177e4SLinus Torvalds /* 2991da177e4SLinus Torvalds * get_write_access() gets write permission for a file. 3001da177e4SLinus Torvalds * put_write_access() releases this write permission. 3011da177e4SLinus Torvalds * This is used for regular files. 3021da177e4SLinus Torvalds * We cannot support write (and maybe mmap read-write shared) accesses and 3031da177e4SLinus Torvalds * MAP_DENYWRITE mmappings simultaneously. The i_writecount field of an inode 3041da177e4SLinus Torvalds * can have the following values: 3051da177e4SLinus Torvalds * 0: no writers, no VM_DENYWRITE mappings 3061da177e4SLinus Torvalds * < 0: (-i_writecount) vm_area_structs with VM_DENYWRITE set exist 3071da177e4SLinus Torvalds * > 0: (i_writecount) users are writing to the file. 3081da177e4SLinus Torvalds * 3091da177e4SLinus Torvalds * Normally we operate on that counter with atomic_{inc,dec} and it's safe 3101da177e4SLinus Torvalds * except for the cases where we don't hold i_writecount yet. Then we need to 3111da177e4SLinus Torvalds * use {get,deny}_write_access() - these functions check the sign and refuse 3121da177e4SLinus Torvalds * to do the change if sign is wrong. Exclusion between them is provided by 3131da177e4SLinus Torvalds * the inode->i_lock spinlock. 3141da177e4SLinus Torvalds */ 3151da177e4SLinus Torvalds 3161da177e4SLinus Torvalds int get_write_access(struct inode * inode) 3171da177e4SLinus Torvalds { 3181da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3191da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) < 0) { 3201da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3211da177e4SLinus Torvalds return -ETXTBSY; 3221da177e4SLinus Torvalds } 3231da177e4SLinus Torvalds atomic_inc(&inode->i_writecount); 3241da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3251da177e4SLinus Torvalds 3261da177e4SLinus Torvalds return 0; 3271da177e4SLinus Torvalds } 3281da177e4SLinus Torvalds 3291da177e4SLinus Torvalds int deny_write_access(struct file * file) 3301da177e4SLinus Torvalds { 3310f7fc9e4SJosef "Jeff" Sipek struct inode *inode = file->f_path.dentry->d_inode; 3321da177e4SLinus Torvalds 3331da177e4SLinus Torvalds spin_lock(&inode->i_lock); 3341da177e4SLinus Torvalds if (atomic_read(&inode->i_writecount) > 0) { 3351da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3361da177e4SLinus Torvalds return -ETXTBSY; 3371da177e4SLinus Torvalds } 3381da177e4SLinus Torvalds atomic_dec(&inode->i_writecount); 3391da177e4SLinus Torvalds spin_unlock(&inode->i_lock); 3401da177e4SLinus Torvalds 3411da177e4SLinus Torvalds return 0; 3421da177e4SLinus Torvalds } 3431da177e4SLinus Torvalds 3441d957f9bSJan Blunck /** 3455dd784d0SJan Blunck * path_get - get a reference to a path 3465dd784d0SJan Blunck * @path: path to get the reference to 3475dd784d0SJan Blunck * 3485dd784d0SJan Blunck * Given a path increment the reference count to the dentry and the vfsmount. 3495dd784d0SJan Blunck */ 3505dd784d0SJan Blunck void path_get(struct path *path) 3515dd784d0SJan Blunck { 3525dd784d0SJan Blunck mntget(path->mnt); 3535dd784d0SJan Blunck dget(path->dentry); 3545dd784d0SJan Blunck } 3555dd784d0SJan Blunck EXPORT_SYMBOL(path_get); 3565dd784d0SJan Blunck 3575dd784d0SJan Blunck /** 3581d957f9bSJan Blunck * path_put - put a reference to a path 3591d957f9bSJan Blunck * @path: path to put the reference to 3601d957f9bSJan Blunck * 3611d957f9bSJan Blunck * Given a path decrement the reference count to the dentry and the vfsmount. 3621d957f9bSJan Blunck */ 3631d957f9bSJan Blunck void path_put(struct path *path) 3641da177e4SLinus Torvalds { 3651d957f9bSJan Blunck dput(path->dentry); 3661d957f9bSJan Blunck mntput(path->mnt); 3671da177e4SLinus Torvalds } 3681d957f9bSJan Blunck EXPORT_SYMBOL(path_put); 3691da177e4SLinus Torvalds 370834f2a4aSTrond Myklebust /** 371834f2a4aSTrond Myklebust * release_open_intent - free up open intent resources 372834f2a4aSTrond Myklebust * @nd: pointer to nameidata 373834f2a4aSTrond Myklebust */ 374834f2a4aSTrond Myklebust void release_open_intent(struct nameidata *nd) 375834f2a4aSTrond Myklebust { 3760f7fc9e4SJosef "Jeff" Sipek if (nd->intent.open.file->f_path.dentry == NULL) 377834f2a4aSTrond Myklebust put_filp(nd->intent.open.file); 378834f2a4aSTrond Myklebust else 379834f2a4aSTrond Myklebust fput(nd->intent.open.file); 380834f2a4aSTrond Myklebust } 381834f2a4aSTrond Myklebust 382bcdc5e01SIan Kent static inline struct dentry * 383bcdc5e01SIan Kent do_revalidate(struct dentry *dentry, struct nameidata *nd) 384bcdc5e01SIan Kent { 385bcdc5e01SIan Kent int status = dentry->d_op->d_revalidate(dentry, nd); 386bcdc5e01SIan Kent if (unlikely(status <= 0)) { 387bcdc5e01SIan Kent /* 388bcdc5e01SIan Kent * The dentry failed validation. 389bcdc5e01SIan Kent * If d_revalidate returned 0 attempt to invalidate 390bcdc5e01SIan Kent * the dentry otherwise d_revalidate is asking us 391bcdc5e01SIan Kent * to return a fail status. 392bcdc5e01SIan Kent */ 393bcdc5e01SIan Kent if (!status) { 394bcdc5e01SIan Kent if (!d_invalidate(dentry)) { 395bcdc5e01SIan Kent dput(dentry); 396bcdc5e01SIan Kent dentry = NULL; 397bcdc5e01SIan Kent } 398bcdc5e01SIan Kent } else { 399bcdc5e01SIan Kent dput(dentry); 400bcdc5e01SIan Kent dentry = ERR_PTR(status); 401bcdc5e01SIan Kent } 402bcdc5e01SIan Kent } 403bcdc5e01SIan Kent return dentry; 404bcdc5e01SIan Kent } 405bcdc5e01SIan Kent 4061da177e4SLinus Torvalds /* 4071da177e4SLinus Torvalds * Internal lookup() using the new generic dcache. 4081da177e4SLinus Torvalds * SMP-safe 4091da177e4SLinus Torvalds */ 4101da177e4SLinus Torvalds static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4111da177e4SLinus Torvalds { 4121da177e4SLinus Torvalds struct dentry * dentry = __d_lookup(parent, name); 4131da177e4SLinus Torvalds 4141da177e4SLinus Torvalds /* lockess __d_lookup may fail due to concurrent d_move() 4151da177e4SLinus Torvalds * in some unrelated directory, so try with d_lookup 4161da177e4SLinus Torvalds */ 4171da177e4SLinus Torvalds if (!dentry) 4181da177e4SLinus Torvalds dentry = d_lookup(parent, name); 4191da177e4SLinus Torvalds 420bcdc5e01SIan Kent if (dentry && dentry->d_op && dentry->d_op->d_revalidate) 421bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 422bcdc5e01SIan Kent 4231da177e4SLinus Torvalds return dentry; 4241da177e4SLinus Torvalds } 4251da177e4SLinus Torvalds 4261da177e4SLinus Torvalds /* 4271da177e4SLinus Torvalds * Short-cut version of permission(), for calling by 4281da177e4SLinus Torvalds * path_walk(), when dcache lock is held. Combines parts 4291da177e4SLinus Torvalds * of permission() and generic_permission(), and tests ONLY for 4301da177e4SLinus Torvalds * MAY_EXEC permission. 4311da177e4SLinus Torvalds * 4321da177e4SLinus Torvalds * If appropriate, check DAC only. If not appropriate, or 4331da177e4SLinus Torvalds * short-cut DAC fails, then call permission() to do more 4341da177e4SLinus Torvalds * complete permission check. 4351da177e4SLinus Torvalds */ 436672b16b2SAl Viro static int exec_permission_lite(struct inode *inode) 4371da177e4SLinus Torvalds { 4381da177e4SLinus Torvalds umode_t mode = inode->i_mode; 4391da177e4SLinus Torvalds 4401da177e4SLinus Torvalds if (inode->i_op && inode->i_op->permission) 4411da177e4SLinus Torvalds return -EAGAIN; 4421da177e4SLinus Torvalds 443da9592edSDavid Howells if (current_fsuid() == inode->i_uid) 4441da177e4SLinus Torvalds mode >>= 6; 4451da177e4SLinus Torvalds else if (in_group_p(inode->i_gid)) 4461da177e4SLinus Torvalds mode >>= 3; 4471da177e4SLinus Torvalds 4481da177e4SLinus Torvalds if (mode & MAY_EXEC) 4491da177e4SLinus Torvalds goto ok; 4501da177e4SLinus Torvalds 4511da177e4SLinus Torvalds if ((inode->i_mode & S_IXUGO) && capable(CAP_DAC_OVERRIDE)) 4521da177e4SLinus Torvalds goto ok; 4531da177e4SLinus Torvalds 4541da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_OVERRIDE)) 4551da177e4SLinus Torvalds goto ok; 4561da177e4SLinus Torvalds 4571da177e4SLinus Torvalds if (S_ISDIR(inode->i_mode) && capable(CAP_DAC_READ_SEARCH)) 4581da177e4SLinus Torvalds goto ok; 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds return -EACCES; 4611da177e4SLinus Torvalds ok: 462b77b0646SAl Viro return security_inode_permission(inode, MAY_EXEC); 4631da177e4SLinus Torvalds } 4641da177e4SLinus Torvalds 4651da177e4SLinus Torvalds /* 4661da177e4SLinus Torvalds * This is called when everything else fails, and we actually have 4671da177e4SLinus Torvalds * to go to the low-level filesystem to find out what we should do.. 4681da177e4SLinus Torvalds * 4691da177e4SLinus Torvalds * We get the directory semaphore, and after getting that we also 4701da177e4SLinus Torvalds * make sure that nobody added the entry to the dcache in the meantime.. 4711da177e4SLinus Torvalds * SMP-safe 4721da177e4SLinus Torvalds */ 4731da177e4SLinus Torvalds static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) 4741da177e4SLinus Torvalds { 4751da177e4SLinus Torvalds struct dentry * result; 4761da177e4SLinus Torvalds struct inode *dir = parent->d_inode; 4771da177e4SLinus Torvalds 4781b1dcc1bSJes Sorensen mutex_lock(&dir->i_mutex); 4791da177e4SLinus Torvalds /* 4801da177e4SLinus Torvalds * First re-do the cached lookup just in case it was created 4811da177e4SLinus Torvalds * while we waited for the directory semaphore.. 4821da177e4SLinus Torvalds * 4831da177e4SLinus Torvalds * FIXME! This could use version numbering or similar to 4841da177e4SLinus Torvalds * avoid unnecessary cache lookups. 4851da177e4SLinus Torvalds * 4861da177e4SLinus Torvalds * The "dcache_lock" is purely to protect the RCU list walker 4871da177e4SLinus Torvalds * from concurrent renames at this point (we mustn't get false 4881da177e4SLinus Torvalds * negatives from the RCU list walk here, unlike the optimistic 4891da177e4SLinus Torvalds * fast walk). 4901da177e4SLinus Torvalds * 4911da177e4SLinus Torvalds * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup 4921da177e4SLinus Torvalds */ 4931da177e4SLinus Torvalds result = d_lookup(parent, name); 4941da177e4SLinus Torvalds if (!result) { 495d70b67c8SMiklos Szeredi struct dentry *dentry; 496d70b67c8SMiklos Szeredi 497d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 498d70b67c8SMiklos Szeredi result = ERR_PTR(-ENOENT); 499d70b67c8SMiklos Szeredi if (IS_DEADDIR(dir)) 500d70b67c8SMiklos Szeredi goto out_unlock; 501d70b67c8SMiklos Szeredi 502d70b67c8SMiklos Szeredi dentry = d_alloc(parent, name); 5031da177e4SLinus Torvalds result = ERR_PTR(-ENOMEM); 5041da177e4SLinus Torvalds if (dentry) { 5051da177e4SLinus Torvalds result = dir->i_op->lookup(dir, dentry, nd); 5061da177e4SLinus Torvalds if (result) 5071da177e4SLinus Torvalds dput(dentry); 5081da177e4SLinus Torvalds else 5091da177e4SLinus Torvalds result = dentry; 5101da177e4SLinus Torvalds } 511d70b67c8SMiklos Szeredi out_unlock: 5121b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5131da177e4SLinus Torvalds return result; 5141da177e4SLinus Torvalds } 5151da177e4SLinus Torvalds 5161da177e4SLinus Torvalds /* 5171da177e4SLinus Torvalds * Uhhuh! Nasty case: the cache was re-populated while 5181da177e4SLinus Torvalds * we waited on the semaphore. Need to revalidate. 5191da177e4SLinus Torvalds */ 5201b1dcc1bSJes Sorensen mutex_unlock(&dir->i_mutex); 5211da177e4SLinus Torvalds if (result->d_op && result->d_op->d_revalidate) { 522bcdc5e01SIan Kent result = do_revalidate(result, nd); 523bcdc5e01SIan Kent if (!result) 5241da177e4SLinus Torvalds result = ERR_PTR(-ENOENT); 5251da177e4SLinus Torvalds } 5261da177e4SLinus Torvalds return result; 5271da177e4SLinus Torvalds } 5281da177e4SLinus Torvalds 529a02f76c3SAl Viro /* 530a02f76c3SAl Viro * Wrapper to retry pathname resolution whenever the underlying 531a02f76c3SAl Viro * file system returns an ESTALE. 532a02f76c3SAl Viro * 533a02f76c3SAl Viro * Retry the whole path once, forcing real lookup requests 534a02f76c3SAl Viro * instead of relying on the dcache. 535a02f76c3SAl Viro */ 536a02f76c3SAl Viro static __always_inline int link_path_walk(const char *name, struct nameidata *nd) 537a02f76c3SAl Viro { 538a02f76c3SAl Viro struct path save = nd->path; 539a02f76c3SAl Viro int result; 540a02f76c3SAl Viro 541a02f76c3SAl Viro /* make sure the stuff we saved doesn't go away */ 542c8e7f449SJan Blunck path_get(&save); 543a02f76c3SAl Viro 544a02f76c3SAl Viro result = __link_path_walk(name, nd); 545a02f76c3SAl Viro if (result == -ESTALE) { 546a02f76c3SAl Viro /* nd->path had been dropped */ 547a02f76c3SAl Viro nd->path = save; 548c8e7f449SJan Blunck path_get(&nd->path); 549a02f76c3SAl Viro nd->flags |= LOOKUP_REVAL; 550a02f76c3SAl Viro result = __link_path_walk(name, nd); 551a02f76c3SAl Viro } 552a02f76c3SAl Viro 553a02f76c3SAl Viro path_put(&save); 554a02f76c3SAl Viro 555a02f76c3SAl Viro return result; 556a02f76c3SAl Viro } 557a02f76c3SAl Viro 558f1662356SArjan van de Ven static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) 5591da177e4SLinus Torvalds { 5601da177e4SLinus Torvalds int res = 0; 5611da177e4SLinus Torvalds char *name; 5621da177e4SLinus Torvalds if (IS_ERR(link)) 5631da177e4SLinus Torvalds goto fail; 5641da177e4SLinus Torvalds 5651da177e4SLinus Torvalds if (*link == '/') { 566b4091d5fSChristoph Hellwig struct fs_struct *fs = current->fs; 567b4091d5fSChristoph Hellwig 5681d957f9bSJan Blunck path_put(&nd->path); 569b4091d5fSChristoph Hellwig 570b4091d5fSChristoph Hellwig read_lock(&fs->lock); 571b4091d5fSChristoph Hellwig nd->path = fs->root; 572b4091d5fSChristoph Hellwig path_get(&fs->root); 573b4091d5fSChristoph Hellwig read_unlock(&fs->lock); 5741da177e4SLinus Torvalds } 575b4091d5fSChristoph Hellwig 5761da177e4SLinus Torvalds res = link_path_walk(link, nd); 5771da177e4SLinus Torvalds if (nd->depth || res || nd->last_type!=LAST_NORM) 5781da177e4SLinus Torvalds return res; 5791da177e4SLinus Torvalds /* 5801da177e4SLinus Torvalds * If it is an iterative symlinks resolution in open_namei() we 5811da177e4SLinus Torvalds * have to copy the last component. And all that crap because of 5821da177e4SLinus Torvalds * bloody create() on broken symlinks. Furrfu... 5831da177e4SLinus Torvalds */ 5841da177e4SLinus Torvalds name = __getname(); 5851da177e4SLinus Torvalds if (unlikely(!name)) { 5861d957f9bSJan Blunck path_put(&nd->path); 5871da177e4SLinus Torvalds return -ENOMEM; 5881da177e4SLinus Torvalds } 5891da177e4SLinus Torvalds strcpy(name, nd->last.name); 5901da177e4SLinus Torvalds nd->last.name = name; 5911da177e4SLinus Torvalds return 0; 5921da177e4SLinus Torvalds fail: 5931d957f9bSJan Blunck path_put(&nd->path); 5941da177e4SLinus Torvalds return PTR_ERR(link); 5951da177e4SLinus Torvalds } 5961da177e4SLinus Torvalds 5971d957f9bSJan Blunck static void path_put_conditional(struct path *path, struct nameidata *nd) 598051d3812SIan Kent { 599051d3812SIan Kent dput(path->dentry); 6004ac91378SJan Blunck if (path->mnt != nd->path.mnt) 601051d3812SIan Kent mntput(path->mnt); 602051d3812SIan Kent } 603051d3812SIan Kent 604051d3812SIan Kent static inline void path_to_nameidata(struct path *path, struct nameidata *nd) 605051d3812SIan Kent { 6064ac91378SJan Blunck dput(nd->path.dentry); 6074ac91378SJan Blunck if (nd->path.mnt != path->mnt) 6084ac91378SJan Blunck mntput(nd->path.mnt); 6094ac91378SJan Blunck nd->path.mnt = path->mnt; 6104ac91378SJan Blunck nd->path.dentry = path->dentry; 611051d3812SIan Kent } 612051d3812SIan Kent 613f1662356SArjan van de Ven static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) 6141da177e4SLinus Torvalds { 6151da177e4SLinus Torvalds int error; 616cc314eefSLinus Torvalds void *cookie; 617cd4e91d3SAl Viro struct dentry *dentry = path->dentry; 6181da177e4SLinus Torvalds 619d671a1cbSAl Viro touch_atime(path->mnt, dentry); 6201da177e4SLinus Torvalds nd_set_link(nd, NULL); 621cd4e91d3SAl Viro 6224ac91378SJan Blunck if (path->mnt != nd->path.mnt) { 623051d3812SIan Kent path_to_nameidata(path, nd); 624051d3812SIan Kent dget(dentry); 625051d3812SIan Kent } 626cd4e91d3SAl Viro mntget(path->mnt); 627cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, nd); 628cc314eefSLinus Torvalds error = PTR_ERR(cookie); 629cc314eefSLinus Torvalds if (!IS_ERR(cookie)) { 6301da177e4SLinus Torvalds char *s = nd_get_link(nd); 631cc314eefSLinus Torvalds error = 0; 6321da177e4SLinus Torvalds if (s) 6331da177e4SLinus Torvalds error = __vfs_follow_link(nd, s); 6341da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 635cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, nd, cookie); 6361da177e4SLinus Torvalds } 63709da5916SJan Blunck path_put(path); 6381da177e4SLinus Torvalds 6391da177e4SLinus Torvalds return error; 6401da177e4SLinus Torvalds } 6411da177e4SLinus Torvalds 6421da177e4SLinus Torvalds /* 6431da177e4SLinus Torvalds * This limits recursive symlink follows to 8, while 6441da177e4SLinus Torvalds * limiting consecutive symlinks to 40. 6451da177e4SLinus Torvalds * 6461da177e4SLinus Torvalds * Without that kind of total limit, nasty chains of consecutive 6471da177e4SLinus Torvalds * symlinks can cause almost arbitrarily long lookups. 6481da177e4SLinus Torvalds */ 64990ebe565SAl Viro static inline int do_follow_link(struct path *path, struct nameidata *nd) 6501da177e4SLinus Torvalds { 6511da177e4SLinus Torvalds int err = -ELOOP; 6521da177e4SLinus Torvalds if (current->link_count >= MAX_NESTED_LINKS) 6531da177e4SLinus Torvalds goto loop; 6541da177e4SLinus Torvalds if (current->total_link_count >= 40) 6551da177e4SLinus Torvalds goto loop; 6561da177e4SLinus Torvalds BUG_ON(nd->depth >= MAX_NESTED_LINKS); 6571da177e4SLinus Torvalds cond_resched(); 65890ebe565SAl Viro err = security_inode_follow_link(path->dentry, nd); 6591da177e4SLinus Torvalds if (err) 6601da177e4SLinus Torvalds goto loop; 6611da177e4SLinus Torvalds current->link_count++; 6621da177e4SLinus Torvalds current->total_link_count++; 6631da177e4SLinus Torvalds nd->depth++; 664cd4e91d3SAl Viro err = __do_follow_link(path, nd); 6651da177e4SLinus Torvalds current->link_count--; 6661da177e4SLinus Torvalds nd->depth--; 6671da177e4SLinus Torvalds return err; 6681da177e4SLinus Torvalds loop: 6691d957f9bSJan Blunck path_put_conditional(path, nd); 6701d957f9bSJan Blunck path_put(&nd->path); 6711da177e4SLinus Torvalds return err; 6721da177e4SLinus Torvalds } 6731da177e4SLinus Torvalds 6741da177e4SLinus Torvalds int follow_up(struct vfsmount **mnt, struct dentry **dentry) 6751da177e4SLinus Torvalds { 6761da177e4SLinus Torvalds struct vfsmount *parent; 6771da177e4SLinus Torvalds struct dentry *mountpoint; 6781da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 6791da177e4SLinus Torvalds parent=(*mnt)->mnt_parent; 6801da177e4SLinus Torvalds if (parent == *mnt) { 6811da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6821da177e4SLinus Torvalds return 0; 6831da177e4SLinus Torvalds } 6841da177e4SLinus Torvalds mntget(parent); 6851da177e4SLinus Torvalds mountpoint=dget((*mnt)->mnt_mountpoint); 6861da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 6871da177e4SLinus Torvalds dput(*dentry); 6881da177e4SLinus Torvalds *dentry = mountpoint; 6891da177e4SLinus Torvalds mntput(*mnt); 6901da177e4SLinus Torvalds *mnt = parent; 6911da177e4SLinus Torvalds return 1; 6921da177e4SLinus Torvalds } 6931da177e4SLinus Torvalds 6941da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 6951da177e4SLinus Torvalds * namespace.c 6961da177e4SLinus Torvalds */ 697463ffb2eSAl Viro static int __follow_mount(struct path *path) 698463ffb2eSAl Viro { 699463ffb2eSAl Viro int res = 0; 700463ffb2eSAl Viro while (d_mountpoint(path->dentry)) { 701463ffb2eSAl Viro struct vfsmount *mounted = lookup_mnt(path->mnt, path->dentry); 702463ffb2eSAl Viro if (!mounted) 703463ffb2eSAl Viro break; 704463ffb2eSAl Viro dput(path->dentry); 705463ffb2eSAl Viro if (res) 706463ffb2eSAl Viro mntput(path->mnt); 707463ffb2eSAl Viro path->mnt = mounted; 708463ffb2eSAl Viro path->dentry = dget(mounted->mnt_root); 709463ffb2eSAl Viro res = 1; 710463ffb2eSAl Viro } 711463ffb2eSAl Viro return res; 712463ffb2eSAl Viro } 713463ffb2eSAl Viro 71458c465ebSAl Viro static void follow_mount(struct vfsmount **mnt, struct dentry **dentry) 7151da177e4SLinus Torvalds { 7161da177e4SLinus Torvalds while (d_mountpoint(*dentry)) { 7171da177e4SLinus Torvalds struct vfsmount *mounted = lookup_mnt(*mnt, *dentry); 7181da177e4SLinus Torvalds if (!mounted) 7191da177e4SLinus Torvalds break; 72058c465ebSAl Viro dput(*dentry); 7211da177e4SLinus Torvalds mntput(*mnt); 7221da177e4SLinus Torvalds *mnt = mounted; 7231da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7241da177e4SLinus Torvalds } 7251da177e4SLinus Torvalds } 7261da177e4SLinus Torvalds 7271da177e4SLinus Torvalds /* no need for dcache_lock, as serialization is taken care in 7281da177e4SLinus Torvalds * namespace.c 7291da177e4SLinus Torvalds */ 730e13b210fSAl Viro int follow_down(struct vfsmount **mnt, struct dentry **dentry) 7311da177e4SLinus Torvalds { 7321da177e4SLinus Torvalds struct vfsmount *mounted; 7331da177e4SLinus Torvalds 7341da177e4SLinus Torvalds mounted = lookup_mnt(*mnt, *dentry); 7351da177e4SLinus Torvalds if (mounted) { 736e13b210fSAl Viro dput(*dentry); 7371da177e4SLinus Torvalds mntput(*mnt); 7381da177e4SLinus Torvalds *mnt = mounted; 7391da177e4SLinus Torvalds *dentry = dget(mounted->mnt_root); 7401da177e4SLinus Torvalds return 1; 7411da177e4SLinus Torvalds } 7421da177e4SLinus Torvalds return 0; 7431da177e4SLinus Torvalds } 7441da177e4SLinus Torvalds 745f1662356SArjan van de Ven static __always_inline void follow_dotdot(struct nameidata *nd) 7461da177e4SLinus Torvalds { 747e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 748e518ddb7SAndreas Mohr 7491da177e4SLinus Torvalds while(1) { 7501da177e4SLinus Torvalds struct vfsmount *parent; 7514ac91378SJan Blunck struct dentry *old = nd->path.dentry; 7521da177e4SLinus Torvalds 753e518ddb7SAndreas Mohr read_lock(&fs->lock); 7546ac08c39SJan Blunck if (nd->path.dentry == fs->root.dentry && 7556ac08c39SJan Blunck nd->path.mnt == fs->root.mnt) { 756e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7571da177e4SLinus Torvalds break; 7581da177e4SLinus Torvalds } 759e518ddb7SAndreas Mohr read_unlock(&fs->lock); 7601da177e4SLinus Torvalds spin_lock(&dcache_lock); 7614ac91378SJan Blunck if (nd->path.dentry != nd->path.mnt->mnt_root) { 7624ac91378SJan Blunck nd->path.dentry = dget(nd->path.dentry->d_parent); 7631da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7641da177e4SLinus Torvalds dput(old); 7651da177e4SLinus Torvalds break; 7661da177e4SLinus Torvalds } 7671da177e4SLinus Torvalds spin_unlock(&dcache_lock); 7681da177e4SLinus Torvalds spin_lock(&vfsmount_lock); 7694ac91378SJan Blunck parent = nd->path.mnt->mnt_parent; 7704ac91378SJan Blunck if (parent == nd->path.mnt) { 7711da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7721da177e4SLinus Torvalds break; 7731da177e4SLinus Torvalds } 7741da177e4SLinus Torvalds mntget(parent); 7754ac91378SJan Blunck nd->path.dentry = dget(nd->path.mnt->mnt_mountpoint); 7761da177e4SLinus Torvalds spin_unlock(&vfsmount_lock); 7771da177e4SLinus Torvalds dput(old); 7784ac91378SJan Blunck mntput(nd->path.mnt); 7794ac91378SJan Blunck nd->path.mnt = parent; 7801da177e4SLinus Torvalds } 7814ac91378SJan Blunck follow_mount(&nd->path.mnt, &nd->path.dentry); 7821da177e4SLinus Torvalds } 7831da177e4SLinus Torvalds 7841da177e4SLinus Torvalds /* 7851da177e4SLinus Torvalds * It's more convoluted than I'd like it to be, but... it's still fairly 7861da177e4SLinus Torvalds * small and for now I'd prefer to have fast path as straight as possible. 7871da177e4SLinus Torvalds * It _is_ time-critical. 7881da177e4SLinus Torvalds */ 7891da177e4SLinus Torvalds static int do_lookup(struct nameidata *nd, struct qstr *name, 7901da177e4SLinus Torvalds struct path *path) 7911da177e4SLinus Torvalds { 7924ac91378SJan Blunck struct vfsmount *mnt = nd->path.mnt; 7934ac91378SJan Blunck struct dentry *dentry = __d_lookup(nd->path.dentry, name); 7941da177e4SLinus Torvalds 7951da177e4SLinus Torvalds if (!dentry) 7961da177e4SLinus Torvalds goto need_lookup; 7971da177e4SLinus Torvalds if (dentry->d_op && dentry->d_op->d_revalidate) 7981da177e4SLinus Torvalds goto need_revalidate; 7991da177e4SLinus Torvalds done: 8001da177e4SLinus Torvalds path->mnt = mnt; 8011da177e4SLinus Torvalds path->dentry = dentry; 802634ee701SAl Viro __follow_mount(path); 8031da177e4SLinus Torvalds return 0; 8041da177e4SLinus Torvalds 8051da177e4SLinus Torvalds need_lookup: 8064ac91378SJan Blunck dentry = real_lookup(nd->path.dentry, name, nd); 8071da177e4SLinus Torvalds if (IS_ERR(dentry)) 8081da177e4SLinus Torvalds goto fail; 8091da177e4SLinus Torvalds goto done; 8101da177e4SLinus Torvalds 8111da177e4SLinus Torvalds need_revalidate: 812bcdc5e01SIan Kent dentry = do_revalidate(dentry, nd); 813bcdc5e01SIan Kent if (!dentry) 8141da177e4SLinus Torvalds goto need_lookup; 815bcdc5e01SIan Kent if (IS_ERR(dentry)) 816bcdc5e01SIan Kent goto fail; 817bcdc5e01SIan Kent goto done; 8181da177e4SLinus Torvalds 8191da177e4SLinus Torvalds fail: 8201da177e4SLinus Torvalds return PTR_ERR(dentry); 8211da177e4SLinus Torvalds } 8221da177e4SLinus Torvalds 8231da177e4SLinus Torvalds /* 8241da177e4SLinus Torvalds * Name resolution. 825ea3834d9SPrasanna Meda * This is the basic name resolution function, turning a pathname into 826ea3834d9SPrasanna Meda * the final dentry. We expect 'base' to be positive and a directory. 8271da177e4SLinus Torvalds * 828ea3834d9SPrasanna Meda * Returns 0 and nd will have valid dentry and mnt on success. 829ea3834d9SPrasanna Meda * Returns error and drops reference to input namei data on failure. 8301da177e4SLinus Torvalds */ 831fc9b52cdSHarvey Harrison static int __link_path_walk(const char *name, struct nameidata *nd) 8321da177e4SLinus Torvalds { 8331da177e4SLinus Torvalds struct path next; 8341da177e4SLinus Torvalds struct inode *inode; 8351da177e4SLinus Torvalds int err; 8361da177e4SLinus Torvalds unsigned int lookup_flags = nd->flags; 8371da177e4SLinus Torvalds 8381da177e4SLinus Torvalds while (*name=='/') 8391da177e4SLinus Torvalds name++; 8401da177e4SLinus Torvalds if (!*name) 8411da177e4SLinus Torvalds goto return_reval; 8421da177e4SLinus Torvalds 8434ac91378SJan Blunck inode = nd->path.dentry->d_inode; 8441da177e4SLinus Torvalds if (nd->depth) 845f55eab82STrond Myklebust lookup_flags = LOOKUP_FOLLOW | (nd->flags & LOOKUP_CONTINUE); 8461da177e4SLinus Torvalds 8471da177e4SLinus Torvalds /* At this point we know we have a real path component. */ 8481da177e4SLinus Torvalds for(;;) { 8491da177e4SLinus Torvalds unsigned long hash; 8501da177e4SLinus Torvalds struct qstr this; 8511da177e4SLinus Torvalds unsigned int c; 8521da177e4SLinus Torvalds 853cdce5d6bSTrond Myklebust nd->flags |= LOOKUP_CONTINUE; 854672b16b2SAl Viro err = exec_permission_lite(inode); 855e4543eddSChristoph Hellwig if (err == -EAGAIN) 856e4543eddSChristoph Hellwig err = vfs_permission(nd, 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 err = -ENOTDIR; 9161da177e4SLinus Torvalds if (!inode->i_op) 9171da177e4SLinus Torvalds goto out_dput; 9181da177e4SLinus Torvalds 9191da177e4SLinus Torvalds if (inode->i_op->follow_link) { 92090ebe565SAl Viro err = do_follow_link(&next, nd); 9211da177e4SLinus Torvalds if (err) 9221da177e4SLinus Torvalds goto return_err; 9231da177e4SLinus Torvalds err = -ENOENT; 9244ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9251da177e4SLinus Torvalds if (!inode) 9261da177e4SLinus Torvalds break; 9271da177e4SLinus Torvalds err = -ENOTDIR; 9281da177e4SLinus Torvalds if (!inode->i_op) 9291da177e4SLinus Torvalds break; 93009dd17d3SMiklos Szeredi } else 93109dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9321da177e4SLinus Torvalds err = -ENOTDIR; 9331da177e4SLinus Torvalds if (!inode->i_op->lookup) 9341da177e4SLinus Torvalds break; 9351da177e4SLinus Torvalds continue; 9361da177e4SLinus Torvalds /* here ends the main loop */ 9371da177e4SLinus Torvalds 9381da177e4SLinus Torvalds last_with_slashes: 9391da177e4SLinus Torvalds lookup_flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; 9401da177e4SLinus Torvalds last_component: 941f55eab82STrond Myklebust /* Clear LOOKUP_CONTINUE iff it was previously unset */ 942f55eab82STrond Myklebust nd->flags &= lookup_flags | ~LOOKUP_CONTINUE; 9431da177e4SLinus Torvalds if (lookup_flags & LOOKUP_PARENT) 9441da177e4SLinus Torvalds goto lookup_parent; 9451da177e4SLinus Torvalds if (this.name[0] == '.') switch (this.len) { 9461da177e4SLinus Torvalds default: 9471da177e4SLinus Torvalds break; 9481da177e4SLinus Torvalds case 2: 9491da177e4SLinus Torvalds if (this.name[1] != '.') 9501da177e4SLinus Torvalds break; 95158c465ebSAl Viro follow_dotdot(nd); 9524ac91378SJan Blunck inode = nd->path.dentry->d_inode; 9531da177e4SLinus Torvalds /* fallthrough */ 9541da177e4SLinus Torvalds case 1: 9551da177e4SLinus Torvalds goto return_reval; 9561da177e4SLinus Torvalds } 9574ac91378SJan Blunck if (nd->path.dentry->d_op && nd->path.dentry->d_op->d_hash) { 9584ac91378SJan Blunck err = nd->path.dentry->d_op->d_hash(nd->path.dentry, 9594ac91378SJan Blunck &this); 9601da177e4SLinus Torvalds if (err < 0) 9611da177e4SLinus Torvalds break; 9621da177e4SLinus Torvalds } 9631da177e4SLinus Torvalds err = do_lookup(nd, &this, &next); 9641da177e4SLinus Torvalds if (err) 9651da177e4SLinus Torvalds break; 9661da177e4SLinus Torvalds inode = next.dentry->d_inode; 9671da177e4SLinus Torvalds if ((lookup_flags & LOOKUP_FOLLOW) 9681da177e4SLinus Torvalds && inode && inode->i_op && inode->i_op->follow_link) { 96990ebe565SAl Viro err = do_follow_link(&next, nd); 9701da177e4SLinus Torvalds if (err) 9711da177e4SLinus Torvalds goto return_err; 9724ac91378SJan Blunck inode = nd->path.dentry->d_inode; 97309dd17d3SMiklos Szeredi } else 97409dd17d3SMiklos Szeredi path_to_nameidata(&next, nd); 9751da177e4SLinus Torvalds err = -ENOENT; 9761da177e4SLinus Torvalds if (!inode) 9771da177e4SLinus Torvalds break; 9781da177e4SLinus Torvalds if (lookup_flags & LOOKUP_DIRECTORY) { 9791da177e4SLinus Torvalds err = -ENOTDIR; 9801da177e4SLinus Torvalds if (!inode->i_op || !inode->i_op->lookup) 9811da177e4SLinus Torvalds break; 9821da177e4SLinus Torvalds } 9831da177e4SLinus Torvalds goto return_base; 9841da177e4SLinus Torvalds lookup_parent: 9851da177e4SLinus Torvalds nd->last = this; 9861da177e4SLinus Torvalds nd->last_type = LAST_NORM; 9871da177e4SLinus Torvalds if (this.name[0] != '.') 9881da177e4SLinus Torvalds goto return_base; 9891da177e4SLinus Torvalds if (this.len == 1) 9901da177e4SLinus Torvalds nd->last_type = LAST_DOT; 9911da177e4SLinus Torvalds else if (this.len == 2 && this.name[1] == '.') 9921da177e4SLinus Torvalds nd->last_type = LAST_DOTDOT; 9931da177e4SLinus Torvalds else 9941da177e4SLinus Torvalds goto return_base; 9951da177e4SLinus Torvalds return_reval: 9961da177e4SLinus Torvalds /* 9971da177e4SLinus Torvalds * We bypassed the ordinary revalidation routines. 9981da177e4SLinus Torvalds * We may need to check the cached dentry for staleness. 9991da177e4SLinus Torvalds */ 10004ac91378SJan Blunck if (nd->path.dentry && nd->path.dentry->d_sb && 10014ac91378SJan Blunck (nd->path.dentry->d_sb->s_type->fs_flags & FS_REVAL_DOT)) { 10021da177e4SLinus Torvalds err = -ESTALE; 10031da177e4SLinus Torvalds /* Note: we do not d_invalidate() */ 10044ac91378SJan Blunck if (!nd->path.dentry->d_op->d_revalidate( 10054ac91378SJan Blunck nd->path.dentry, nd)) 10061da177e4SLinus Torvalds break; 10071da177e4SLinus Torvalds } 10081da177e4SLinus Torvalds return_base: 10091da177e4SLinus Torvalds return 0; 10101da177e4SLinus Torvalds out_dput: 10111d957f9bSJan Blunck path_put_conditional(&next, nd); 10121da177e4SLinus Torvalds break; 10131da177e4SLinus Torvalds } 10141d957f9bSJan Blunck path_put(&nd->path); 10151da177e4SLinus Torvalds return_err: 10161da177e4SLinus Torvalds return err; 10171da177e4SLinus Torvalds } 10181da177e4SLinus Torvalds 1019fc9b52cdSHarvey Harrison static int path_walk(const char *name, struct nameidata *nd) 10201da177e4SLinus Torvalds { 10211da177e4SLinus Torvalds current->total_link_count = 0; 10221da177e4SLinus Torvalds return link_path_walk(name, nd); 10231da177e4SLinus Torvalds } 10241da177e4SLinus Torvalds 1025ea3834d9SPrasanna Meda /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ 1026fc9b52cdSHarvey Harrison static int do_path_lookup(int dfd, const char *name, 10275590ff0dSUlrich Drepper unsigned int flags, struct nameidata *nd) 10281da177e4SLinus Torvalds { 1029ea3834d9SPrasanna Meda int retval = 0; 1030170aa3d0SUlrich Drepper int fput_needed; 1031170aa3d0SUlrich Drepper struct file *file; 1032e518ddb7SAndreas Mohr struct fs_struct *fs = current->fs; 10331da177e4SLinus Torvalds 10341da177e4SLinus Torvalds nd->last_type = LAST_ROOT; /* if there are only slashes... */ 10351da177e4SLinus Torvalds nd->flags = flags; 10361da177e4SLinus Torvalds nd->depth = 0; 10371da177e4SLinus Torvalds 10381da177e4SLinus Torvalds if (*name=='/') { 1039e518ddb7SAndreas Mohr read_lock(&fs->lock); 10406ac08c39SJan Blunck nd->path = fs->root; 10416ac08c39SJan Blunck path_get(&fs->root); 1042e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10435590ff0dSUlrich Drepper } else if (dfd == AT_FDCWD) { 1044e518ddb7SAndreas Mohr read_lock(&fs->lock); 10456ac08c39SJan Blunck nd->path = fs->pwd; 10466ac08c39SJan Blunck path_get(&fs->pwd); 1047e518ddb7SAndreas Mohr read_unlock(&fs->lock); 10485590ff0dSUlrich Drepper } else { 10495590ff0dSUlrich Drepper struct dentry *dentry; 10505590ff0dSUlrich Drepper 10515590ff0dSUlrich Drepper file = fget_light(dfd, &fput_needed); 10525590ff0dSUlrich Drepper retval = -EBADF; 1053170aa3d0SUlrich Drepper if (!file) 10546d09bb62STrond Myklebust goto out_fail; 10555590ff0dSUlrich Drepper 10560f7fc9e4SJosef "Jeff" Sipek dentry = file->f_path.dentry; 10575590ff0dSUlrich Drepper 10585590ff0dSUlrich Drepper retval = -ENOTDIR; 1059170aa3d0SUlrich Drepper if (!S_ISDIR(dentry->d_inode->i_mode)) 10606d09bb62STrond Myklebust goto fput_fail; 10615590ff0dSUlrich Drepper 10625590ff0dSUlrich Drepper retval = file_permission(file, MAY_EXEC); 1063170aa3d0SUlrich Drepper if (retval) 10646d09bb62STrond Myklebust goto fput_fail; 10655590ff0dSUlrich Drepper 10665dd784d0SJan Blunck nd->path = file->f_path; 10675dd784d0SJan Blunck path_get(&file->f_path); 10685590ff0dSUlrich Drepper 10695590ff0dSUlrich Drepper fput_light(file, fput_needed); 10701da177e4SLinus Torvalds } 10712dfdd266SJosef 'Jeff' Sipek 10722dfdd266SJosef 'Jeff' Sipek retval = path_walk(name, nd); 10734ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 10744ac91378SJan Blunck nd->path.dentry->d_inode)) 10754ac91378SJan Blunck audit_inode(name, nd->path.dentry); 10766d09bb62STrond Myklebust out_fail: 1077170aa3d0SUlrich Drepper return retval; 1078170aa3d0SUlrich Drepper 10796d09bb62STrond Myklebust fput_fail: 1080170aa3d0SUlrich Drepper fput_light(file, fput_needed); 10816d09bb62STrond Myklebust goto out_fail; 10821da177e4SLinus Torvalds } 10831da177e4SLinus Torvalds 1084fc9b52cdSHarvey Harrison int path_lookup(const char *name, unsigned int flags, 10855590ff0dSUlrich Drepper struct nameidata *nd) 10865590ff0dSUlrich Drepper { 10875590ff0dSUlrich Drepper return do_path_lookup(AT_FDCWD, name, flags, nd); 10885590ff0dSUlrich Drepper } 10895590ff0dSUlrich Drepper 1090d1811465SAl Viro int kern_path(const char *name, unsigned int flags, struct path *path) 1091d1811465SAl Viro { 1092d1811465SAl Viro struct nameidata nd; 1093d1811465SAl Viro int res = do_path_lookup(AT_FDCWD, name, flags, &nd); 1094d1811465SAl Viro if (!res) 1095d1811465SAl Viro *path = nd.path; 1096d1811465SAl Viro return res; 1097d1811465SAl Viro } 1098d1811465SAl Viro 109916f18200SJosef 'Jeff' Sipek /** 110016f18200SJosef 'Jeff' Sipek * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair 110116f18200SJosef 'Jeff' Sipek * @dentry: pointer to dentry of the base directory 110216f18200SJosef 'Jeff' Sipek * @mnt: pointer to vfs mount of the base directory 110316f18200SJosef 'Jeff' Sipek * @name: pointer to file name 110416f18200SJosef 'Jeff' Sipek * @flags: lookup flags 110516f18200SJosef 'Jeff' Sipek * @nd: pointer to nameidata 110616f18200SJosef 'Jeff' Sipek */ 110716f18200SJosef 'Jeff' Sipek int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, 110816f18200SJosef 'Jeff' Sipek const char *name, unsigned int flags, 110916f18200SJosef 'Jeff' Sipek struct nameidata *nd) 111016f18200SJosef 'Jeff' Sipek { 111116f18200SJosef 'Jeff' Sipek int retval; 111216f18200SJosef 'Jeff' Sipek 111316f18200SJosef 'Jeff' Sipek /* same as do_path_lookup */ 111416f18200SJosef 'Jeff' Sipek nd->last_type = LAST_ROOT; 111516f18200SJosef 'Jeff' Sipek nd->flags = flags; 111616f18200SJosef 'Jeff' Sipek nd->depth = 0; 111716f18200SJosef 'Jeff' Sipek 1118c8e7f449SJan Blunck nd->path.dentry = dentry; 1119c8e7f449SJan Blunck nd->path.mnt = mnt; 1120c8e7f449SJan Blunck path_get(&nd->path); 112116f18200SJosef 'Jeff' Sipek 112216f18200SJosef 'Jeff' Sipek retval = path_walk(name, nd); 11234ac91378SJan Blunck if (unlikely(!retval && !audit_dummy_context() && nd->path.dentry && 11244ac91378SJan Blunck nd->path.dentry->d_inode)) 11254ac91378SJan Blunck audit_inode(name, nd->path.dentry); 112616f18200SJosef 'Jeff' Sipek 112716f18200SJosef 'Jeff' Sipek return retval; 112816f18200SJosef 'Jeff' Sipek 112916f18200SJosef 'Jeff' Sipek } 113016f18200SJosef 'Jeff' Sipek 1131834f2a4aSTrond Myklebust /** 1132834f2a4aSTrond Myklebust * path_lookup_open - lookup a file path with open intent 11337045f37bSMartin Waitz * @dfd: the directory to use as base, or AT_FDCWD 1134834f2a4aSTrond Myklebust * @name: pointer to file name 1135834f2a4aSTrond Myklebust * @lookup_flags: lookup intent flags 1136834f2a4aSTrond Myklebust * @nd: pointer to nameidata 1137834f2a4aSTrond Myklebust * @open_flags: open intent flags 1138834f2a4aSTrond Myklebust */ 11395590ff0dSUlrich Drepper int path_lookup_open(int dfd, const char *name, unsigned int lookup_flags, 1140834f2a4aSTrond Myklebust struct nameidata *nd, int open_flags) 1141834f2a4aSTrond Myklebust { 11428737f3a1SAl Viro struct file *filp = get_empty_filp(); 11438737f3a1SAl Viro int err; 1144834f2a4aSTrond Myklebust 11458737f3a1SAl Viro if (filp == NULL) 11468737f3a1SAl Viro return -ENFILE; 11478737f3a1SAl Viro nd->intent.open.file = filp; 11488737f3a1SAl Viro nd->intent.open.flags = open_flags; 11498737f3a1SAl Viro nd->intent.open.create_mode = 0; 11508737f3a1SAl Viro err = do_path_lookup(dfd, name, lookup_flags|LOOKUP_OPEN, nd); 11518737f3a1SAl Viro if (IS_ERR(nd->intent.open.file)) { 11528737f3a1SAl Viro if (err == 0) { 11538737f3a1SAl Viro err = PTR_ERR(nd->intent.open.file); 11548737f3a1SAl Viro path_put(&nd->path); 11558737f3a1SAl Viro } 11568737f3a1SAl Viro } else if (err != 0) 11578737f3a1SAl Viro release_open_intent(nd); 11588737f3a1SAl Viro return err; 1159834f2a4aSTrond Myklebust } 1160834f2a4aSTrond Myklebust 1161eead1911SChristoph Hellwig static struct dentry *__lookup_hash(struct qstr *name, 1162eead1911SChristoph Hellwig struct dentry *base, struct nameidata *nd) 11631da177e4SLinus Torvalds { 11641da177e4SLinus Torvalds struct dentry *dentry; 11651da177e4SLinus Torvalds struct inode *inode; 11661da177e4SLinus Torvalds int err; 11671da177e4SLinus Torvalds 11681da177e4SLinus Torvalds inode = base->d_inode; 11691da177e4SLinus Torvalds 11701da177e4SLinus Torvalds /* 11711da177e4SLinus Torvalds * See if the low-level filesystem might want 11721da177e4SLinus Torvalds * to use its own hash.. 11731da177e4SLinus Torvalds */ 11741da177e4SLinus Torvalds if (base->d_op && base->d_op->d_hash) { 11751da177e4SLinus Torvalds err = base->d_op->d_hash(base, name); 11761da177e4SLinus Torvalds dentry = ERR_PTR(err); 11771da177e4SLinus Torvalds if (err < 0) 11781da177e4SLinus Torvalds goto out; 11791da177e4SLinus Torvalds } 11801da177e4SLinus Torvalds 11811da177e4SLinus Torvalds dentry = cached_lookup(base, name, nd); 11821da177e4SLinus Torvalds if (!dentry) { 1183d70b67c8SMiklos Szeredi struct dentry *new; 1184d70b67c8SMiklos Szeredi 1185d70b67c8SMiklos Szeredi /* Don't create child dentry for a dead directory. */ 1186d70b67c8SMiklos Szeredi dentry = ERR_PTR(-ENOENT); 1187d70b67c8SMiklos Szeredi if (IS_DEADDIR(inode)) 1188d70b67c8SMiklos Szeredi goto out; 1189d70b67c8SMiklos Szeredi 1190d70b67c8SMiklos Szeredi new = d_alloc(base, name); 11911da177e4SLinus Torvalds dentry = ERR_PTR(-ENOMEM); 11921da177e4SLinus Torvalds if (!new) 11931da177e4SLinus Torvalds goto out; 11941da177e4SLinus Torvalds dentry = inode->i_op->lookup(inode, new, nd); 11951da177e4SLinus Torvalds if (!dentry) 11961da177e4SLinus Torvalds dentry = new; 11971da177e4SLinus Torvalds else 11981da177e4SLinus Torvalds dput(new); 11991da177e4SLinus Torvalds } 12001da177e4SLinus Torvalds out: 12011da177e4SLinus Torvalds return dentry; 12021da177e4SLinus Torvalds } 12031da177e4SLinus Torvalds 1204057f6c01SJames Morris /* 1205057f6c01SJames Morris * Restricted form of lookup. Doesn't follow links, single-component only, 1206057f6c01SJames Morris * needs parent already locked. Doesn't follow mounts. 1207057f6c01SJames Morris * SMP-safe. 1208057f6c01SJames Morris */ 1209a244e169SAdrian Bunk static struct dentry *lookup_hash(struct nameidata *nd) 12101da177e4SLinus Torvalds { 1211eead1911SChristoph Hellwig int err; 1212eead1911SChristoph Hellwig 1213f419a2e3SAl Viro err = inode_permission(nd->path.dentry->d_inode, MAY_EXEC); 1214eead1911SChristoph Hellwig if (err) 1215eead1911SChristoph Hellwig return ERR_PTR(err); 12164ac91378SJan Blunck return __lookup_hash(&nd->last, nd->path.dentry, nd); 12171da177e4SLinus Torvalds } 12181da177e4SLinus Torvalds 1219eead1911SChristoph Hellwig static int __lookup_one_len(const char *name, struct qstr *this, 1220eead1911SChristoph Hellwig struct dentry *base, int len) 12211da177e4SLinus Torvalds { 12221da177e4SLinus Torvalds unsigned long hash; 12231da177e4SLinus Torvalds unsigned int c; 12241da177e4SLinus Torvalds 1225057f6c01SJames Morris this->name = name; 1226057f6c01SJames Morris this->len = len; 12271da177e4SLinus Torvalds if (!len) 1228057f6c01SJames Morris return -EACCES; 12291da177e4SLinus Torvalds 12301da177e4SLinus Torvalds hash = init_name_hash(); 12311da177e4SLinus Torvalds while (len--) { 12321da177e4SLinus Torvalds c = *(const unsigned char *)name++; 12331da177e4SLinus Torvalds if (c == '/' || c == '\0') 1234057f6c01SJames Morris return -EACCES; 12351da177e4SLinus Torvalds hash = partial_name_hash(c, hash); 12361da177e4SLinus Torvalds } 1237057f6c01SJames Morris this->hash = end_name_hash(hash); 1238057f6c01SJames Morris return 0; 1239057f6c01SJames Morris } 12401da177e4SLinus Torvalds 1241eead1911SChristoph Hellwig /** 1242a6b91919SRandy Dunlap * lookup_one_len - filesystem helper to lookup single pathname component 1243eead1911SChristoph Hellwig * @name: pathname component to lookup 1244eead1911SChristoph Hellwig * @base: base directory to lookup from 1245eead1911SChristoph Hellwig * @len: maximum length @len should be interpreted to 1246eead1911SChristoph Hellwig * 1247a6b91919SRandy Dunlap * Note that this routine is purely a helper for filesystem usage and should 1248a6b91919SRandy Dunlap * not be called by generic code. Also note that by using this function the 1249eead1911SChristoph Hellwig * nameidata argument is passed to the filesystem methods and a filesystem 1250eead1911SChristoph Hellwig * using this helper needs to be prepared for that. 1251eead1911SChristoph Hellwig */ 1252057f6c01SJames Morris struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) 1253057f6c01SJames Morris { 1254057f6c01SJames Morris int err; 1255057f6c01SJames Morris struct qstr this; 1256057f6c01SJames Morris 1257057f6c01SJames Morris err = __lookup_one_len(name, &this, base, len); 1258057f6c01SJames Morris if (err) 1259057f6c01SJames Morris return ERR_PTR(err); 1260eead1911SChristoph Hellwig 1261f419a2e3SAl Viro err = inode_permission(base->d_inode, MAY_EXEC); 1262eead1911SChristoph Hellwig if (err) 1263eead1911SChristoph Hellwig return ERR_PTR(err); 126449705b77SChristoph Hellwig return __lookup_hash(&this, base, NULL); 1265057f6c01SJames Morris } 1266057f6c01SJames Morris 1267eead1911SChristoph Hellwig /** 1268eead1911SChristoph Hellwig * lookup_one_noperm - bad hack for sysfs 1269eead1911SChristoph Hellwig * @name: pathname component to lookup 1270eead1911SChristoph Hellwig * @base: base directory to lookup from 1271eead1911SChristoph Hellwig * 1272eead1911SChristoph Hellwig * This is a variant of lookup_one_len that doesn't perform any permission 1273eead1911SChristoph Hellwig * checks. It's a horrible hack to work around the braindead sysfs 1274eead1911SChristoph Hellwig * architecture and should not be used anywhere else. 1275eead1911SChristoph Hellwig * 1276eead1911SChristoph Hellwig * DON'T USE THIS FUNCTION EVER, thanks. 1277eead1911SChristoph Hellwig */ 1278eead1911SChristoph Hellwig struct dentry *lookup_one_noperm(const char *name, struct dentry *base) 1279057f6c01SJames Morris { 1280057f6c01SJames Morris int err; 1281057f6c01SJames Morris struct qstr this; 1282057f6c01SJames Morris 1283eead1911SChristoph Hellwig err = __lookup_one_len(name, &this, base, strlen(name)); 1284057f6c01SJames Morris if (err) 1285057f6c01SJames Morris return ERR_PTR(err); 1286eead1911SChristoph Hellwig return __lookup_hash(&this, base, NULL); 12871da177e4SLinus Torvalds } 12881da177e4SLinus Torvalds 12892d8f3038SAl Viro int user_path_at(int dfd, const char __user *name, unsigned flags, 12902d8f3038SAl Viro struct path *path) 12911da177e4SLinus Torvalds { 12922d8f3038SAl Viro struct nameidata nd; 12931da177e4SLinus Torvalds char *tmp = getname(name); 12941da177e4SLinus Torvalds int err = PTR_ERR(tmp); 12951da177e4SLinus Torvalds if (!IS_ERR(tmp)) { 12962d8f3038SAl Viro 12972d8f3038SAl Viro BUG_ON(flags & LOOKUP_PARENT); 12982d8f3038SAl Viro 12992d8f3038SAl Viro err = do_path_lookup(dfd, tmp, flags, &nd); 13001da177e4SLinus Torvalds putname(tmp); 13012d8f3038SAl Viro if (!err) 13022d8f3038SAl Viro *path = nd.path; 13031da177e4SLinus Torvalds } 13041da177e4SLinus Torvalds return err; 13051da177e4SLinus Torvalds } 13061da177e4SLinus Torvalds 13072ad94ae6SAl Viro static int user_path_parent(int dfd, const char __user *path, 13082ad94ae6SAl Viro struct nameidata *nd, char **name) 13092ad94ae6SAl Viro { 13102ad94ae6SAl Viro char *s = getname(path); 13112ad94ae6SAl Viro int error; 13122ad94ae6SAl Viro 13132ad94ae6SAl Viro if (IS_ERR(s)) 13142ad94ae6SAl Viro return PTR_ERR(s); 13152ad94ae6SAl Viro 13162ad94ae6SAl Viro error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd); 13172ad94ae6SAl Viro if (error) 13182ad94ae6SAl Viro putname(s); 13192ad94ae6SAl Viro else 13202ad94ae6SAl Viro *name = s; 13212ad94ae6SAl Viro 13222ad94ae6SAl Viro return error; 13232ad94ae6SAl Viro } 13242ad94ae6SAl Viro 13251da177e4SLinus Torvalds /* 13261da177e4SLinus Torvalds * It's inline, so penalty for filesystems that don't use sticky bit is 13271da177e4SLinus Torvalds * minimal. 13281da177e4SLinus Torvalds */ 13291da177e4SLinus Torvalds static inline int check_sticky(struct inode *dir, struct inode *inode) 13301da177e4SLinus Torvalds { 1331da9592edSDavid Howells uid_t fsuid = current_fsuid(); 1332da9592edSDavid Howells 13331da177e4SLinus Torvalds if (!(dir->i_mode & S_ISVTX)) 13341da177e4SLinus Torvalds return 0; 1335da9592edSDavid Howells if (inode->i_uid == fsuid) 13361da177e4SLinus Torvalds return 0; 1337da9592edSDavid Howells if (dir->i_uid == fsuid) 13381da177e4SLinus Torvalds return 0; 13391da177e4SLinus Torvalds return !capable(CAP_FOWNER); 13401da177e4SLinus Torvalds } 13411da177e4SLinus Torvalds 13421da177e4SLinus Torvalds /* 13431da177e4SLinus Torvalds * Check whether we can remove a link victim from directory dir, check 13441da177e4SLinus Torvalds * whether the type of victim is right. 13451da177e4SLinus Torvalds * 1. We can't do it if dir is read-only (done in permission()) 13461da177e4SLinus Torvalds * 2. We should have write and exec permissions on dir 13471da177e4SLinus Torvalds * 3. We can't remove anything from append-only dir 13481da177e4SLinus Torvalds * 4. We can't do anything with immutable dir (done in permission()) 13491da177e4SLinus Torvalds * 5. If the sticky bit on dir is set we should either 13501da177e4SLinus Torvalds * a. be owner of dir, or 13511da177e4SLinus Torvalds * b. be owner of victim, or 13521da177e4SLinus Torvalds * c. have CAP_FOWNER capability 13531da177e4SLinus Torvalds * 6. If the victim is append-only or immutable we can't do antyhing with 13541da177e4SLinus Torvalds * links pointing to it. 13551da177e4SLinus Torvalds * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. 13561da177e4SLinus Torvalds * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. 13571da177e4SLinus Torvalds * 9. We can't remove a root or mountpoint. 13581da177e4SLinus Torvalds * 10. We don't allow removal of NFS sillyrenamed files; it's handled by 13591da177e4SLinus Torvalds * nfs_async_unlink(). 13601da177e4SLinus Torvalds */ 1361858119e1SArjan van de Ven static int may_delete(struct inode *dir,struct dentry *victim,int isdir) 13621da177e4SLinus Torvalds { 13631da177e4SLinus Torvalds int error; 13641da177e4SLinus Torvalds 13651da177e4SLinus Torvalds if (!victim->d_inode) 13661da177e4SLinus Torvalds return -ENOENT; 13671da177e4SLinus Torvalds 13681da177e4SLinus Torvalds BUG_ON(victim->d_parent->d_inode != dir); 13695a190ae6SAl Viro audit_inode_child(victim->d_name.name, victim, dir); 13701da177e4SLinus Torvalds 1371f419a2e3SAl Viro error = inode_permission(dir, MAY_WRITE | MAY_EXEC); 13721da177e4SLinus Torvalds if (error) 13731da177e4SLinus Torvalds return error; 13741da177e4SLinus Torvalds if (IS_APPEND(dir)) 13751da177e4SLinus Torvalds return -EPERM; 13761da177e4SLinus Torvalds if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| 1377f9454548SHugh Dickins IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) 13781da177e4SLinus Torvalds return -EPERM; 13791da177e4SLinus Torvalds if (isdir) { 13801da177e4SLinus Torvalds if (!S_ISDIR(victim->d_inode->i_mode)) 13811da177e4SLinus Torvalds return -ENOTDIR; 13821da177e4SLinus Torvalds if (IS_ROOT(victim)) 13831da177e4SLinus Torvalds return -EBUSY; 13841da177e4SLinus Torvalds } else if (S_ISDIR(victim->d_inode->i_mode)) 13851da177e4SLinus Torvalds return -EISDIR; 13861da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 13871da177e4SLinus Torvalds return -ENOENT; 13881da177e4SLinus Torvalds if (victim->d_flags & DCACHE_NFSFS_RENAMED) 13891da177e4SLinus Torvalds return -EBUSY; 13901da177e4SLinus Torvalds return 0; 13911da177e4SLinus Torvalds } 13921da177e4SLinus Torvalds 13931da177e4SLinus Torvalds /* Check whether we can create an object with dentry child in directory 13941da177e4SLinus Torvalds * dir. 13951da177e4SLinus Torvalds * 1. We can't do it if child already exists (open has special treatment for 13961da177e4SLinus Torvalds * this case, but since we are inlined it's OK) 13971da177e4SLinus Torvalds * 2. We can't do it if dir is read-only (done in permission()) 13981da177e4SLinus Torvalds * 3. We should have write and exec permissions on dir 13991da177e4SLinus Torvalds * 4. We can't do it if dir is immutable (done in permission()) 14001da177e4SLinus Torvalds */ 1401a95164d9SMiklos Szeredi static inline int may_create(struct inode *dir, struct dentry *child) 14021da177e4SLinus Torvalds { 14031da177e4SLinus Torvalds if (child->d_inode) 14041da177e4SLinus Torvalds return -EEXIST; 14051da177e4SLinus Torvalds if (IS_DEADDIR(dir)) 14061da177e4SLinus Torvalds return -ENOENT; 1407f419a2e3SAl Viro return inode_permission(dir, MAY_WRITE | MAY_EXEC); 14081da177e4SLinus Torvalds } 14091da177e4SLinus Torvalds 14101da177e4SLinus Torvalds /* 14111da177e4SLinus Torvalds * O_DIRECTORY translates into forcing a directory lookup. 14121da177e4SLinus Torvalds */ 14131da177e4SLinus Torvalds static inline int lookup_flags(unsigned int f) 14141da177e4SLinus Torvalds { 14151da177e4SLinus Torvalds unsigned long retval = LOOKUP_FOLLOW; 14161da177e4SLinus Torvalds 14171da177e4SLinus Torvalds if (f & O_NOFOLLOW) 14181da177e4SLinus Torvalds retval &= ~LOOKUP_FOLLOW; 14191da177e4SLinus Torvalds 14201da177e4SLinus Torvalds if (f & O_DIRECTORY) 14211da177e4SLinus Torvalds retval |= LOOKUP_DIRECTORY; 14221da177e4SLinus Torvalds 14231da177e4SLinus Torvalds return retval; 14241da177e4SLinus Torvalds } 14251da177e4SLinus Torvalds 14261da177e4SLinus Torvalds /* 14271da177e4SLinus Torvalds * p1 and p2 should be directories on the same fs. 14281da177e4SLinus Torvalds */ 14291da177e4SLinus Torvalds struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) 14301da177e4SLinus Torvalds { 14311da177e4SLinus Torvalds struct dentry *p; 14321da177e4SLinus Torvalds 14331da177e4SLinus Torvalds if (p1 == p2) { 1434f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 14351da177e4SLinus Torvalds return NULL; 14361da177e4SLinus Torvalds } 14371da177e4SLinus Torvalds 1438a11f3a05SArjan van de Ven mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14391da177e4SLinus Torvalds 1440e2761a11SOGAWA Hirofumi p = d_ancestor(p2, p1); 1441e2761a11SOGAWA Hirofumi if (p) { 1442f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); 1443f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); 14441da177e4SLinus Torvalds return p; 14451da177e4SLinus Torvalds } 14461da177e4SLinus Torvalds 1447e2761a11SOGAWA Hirofumi p = d_ancestor(p1, p2); 1448e2761a11SOGAWA Hirofumi if (p) { 1449f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1450f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14511da177e4SLinus Torvalds return p; 14521da177e4SLinus Torvalds } 14531da177e4SLinus Torvalds 1454f2eace23SIngo Molnar mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); 1455f2eace23SIngo Molnar mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); 14561da177e4SLinus Torvalds return NULL; 14571da177e4SLinus Torvalds } 14581da177e4SLinus Torvalds 14591da177e4SLinus Torvalds void unlock_rename(struct dentry *p1, struct dentry *p2) 14601da177e4SLinus Torvalds { 14611b1dcc1bSJes Sorensen mutex_unlock(&p1->d_inode->i_mutex); 14621da177e4SLinus Torvalds if (p1 != p2) { 14631b1dcc1bSJes Sorensen mutex_unlock(&p2->d_inode->i_mutex); 1464a11f3a05SArjan van de Ven mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); 14651da177e4SLinus Torvalds } 14661da177e4SLinus Torvalds } 14671da177e4SLinus Torvalds 14681da177e4SLinus Torvalds int vfs_create(struct inode *dir, struct dentry *dentry, int mode, 14691da177e4SLinus Torvalds struct nameidata *nd) 14701da177e4SLinus Torvalds { 1471a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 14721da177e4SLinus Torvalds 14731da177e4SLinus Torvalds if (error) 14741da177e4SLinus Torvalds return error; 14751da177e4SLinus Torvalds 14761da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->create) 14771da177e4SLinus Torvalds return -EACCES; /* shouldn't it be ENOSYS? */ 14781da177e4SLinus Torvalds mode &= S_IALLUGO; 14791da177e4SLinus Torvalds mode |= S_IFREG; 14801da177e4SLinus Torvalds error = security_inode_create(dir, dentry, mode); 14811da177e4SLinus Torvalds if (error) 14821da177e4SLinus Torvalds return error; 14831da177e4SLinus Torvalds DQUOT_INIT(dir); 14841da177e4SLinus Torvalds error = dir->i_op->create(dir, dentry, mode, nd); 1485a74574aaSStephen Smalley if (!error) 1486f38aa942SAmy Griffis fsnotify_create(dir, dentry); 14871da177e4SLinus Torvalds return error; 14881da177e4SLinus Torvalds } 14891da177e4SLinus Torvalds 14903fb64190SChristoph Hellwig int may_open(struct path *path, int acc_mode, int flag) 14911da177e4SLinus Torvalds { 14923fb64190SChristoph Hellwig struct dentry *dentry = path->dentry; 14931da177e4SLinus Torvalds struct inode *inode = dentry->d_inode; 14941da177e4SLinus Torvalds int error; 14951da177e4SLinus Torvalds 14961da177e4SLinus Torvalds if (!inode) 14971da177e4SLinus Torvalds return -ENOENT; 14981da177e4SLinus Torvalds 14991da177e4SLinus Torvalds if (S_ISLNK(inode->i_mode)) 15001da177e4SLinus Torvalds return -ELOOP; 15011da177e4SLinus Torvalds 1502974a9f0bSLinus Torvalds if (S_ISDIR(inode->i_mode) && (acc_mode & MAY_WRITE)) 15031da177e4SLinus Torvalds return -EISDIR; 15041da177e4SLinus Torvalds 15051da177e4SLinus Torvalds /* 15061da177e4SLinus Torvalds * FIFO's, sockets and device files are special: they don't 15071da177e4SLinus Torvalds * actually live on the filesystem itself, and as such you 15081da177e4SLinus Torvalds * can write to them even if the filesystem is read-only. 15091da177e4SLinus Torvalds */ 15101da177e4SLinus Torvalds if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) { 15111da177e4SLinus Torvalds flag &= ~O_TRUNC; 15121da177e4SLinus Torvalds } else if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode)) { 15133fb64190SChristoph Hellwig if (path->mnt->mnt_flags & MNT_NODEV) 15141da177e4SLinus Torvalds return -EACCES; 15151da177e4SLinus Torvalds 15161da177e4SLinus Torvalds flag &= ~O_TRUNC; 15174a3fd211SDave Hansen } 1518b41572e9SDave Hansen 15193fb64190SChristoph Hellwig error = inode_permission(inode, acc_mode); 1520b41572e9SDave Hansen if (error) 1521b41572e9SDave Hansen return error; 15221da177e4SLinus Torvalds /* 15231da177e4SLinus Torvalds * An append-only file must be opened in append mode for writing. 15241da177e4SLinus Torvalds */ 15251da177e4SLinus Torvalds if (IS_APPEND(inode)) { 15261da177e4SLinus Torvalds if ((flag & FMODE_WRITE) && !(flag & O_APPEND)) 15271da177e4SLinus Torvalds return -EPERM; 15281da177e4SLinus Torvalds if (flag & O_TRUNC) 15291da177e4SLinus Torvalds return -EPERM; 15301da177e4SLinus Torvalds } 15311da177e4SLinus Torvalds 15321da177e4SLinus Torvalds /* O_NOATIME can only be set by the owner or superuser */ 15331da177e4SLinus Torvalds if (flag & O_NOATIME) 15343bd858abSSatyam Sharma if (!is_owner_or_cap(inode)) 15351da177e4SLinus Torvalds return -EPERM; 15361da177e4SLinus Torvalds 15371da177e4SLinus Torvalds /* 15381da177e4SLinus Torvalds * Ensure there are no outstanding leases on the file. 15391da177e4SLinus Torvalds */ 15401da177e4SLinus Torvalds error = break_lease(inode, flag); 15411da177e4SLinus Torvalds if (error) 15421da177e4SLinus Torvalds return error; 15431da177e4SLinus Torvalds 15441da177e4SLinus Torvalds if (flag & O_TRUNC) { 15451da177e4SLinus Torvalds error = get_write_access(inode); 15461da177e4SLinus Torvalds if (error) 15471da177e4SLinus Torvalds return error; 15481da177e4SLinus Torvalds 15491da177e4SLinus Torvalds /* 15501da177e4SLinus Torvalds * Refuse to truncate files with mandatory locks held on them. 15511da177e4SLinus Torvalds */ 15521da177e4SLinus Torvalds error = locks_verify_locked(inode); 1553be6d3e56SKentaro Takeda if (!error) 15543fb64190SChristoph Hellwig error = security_path_truncate(path, 0, 1555be6d3e56SKentaro Takeda ATTR_MTIME|ATTR_CTIME|ATTR_OPEN); 15561da177e4SLinus Torvalds if (!error) { 15571da177e4SLinus Torvalds DQUOT_INIT(inode); 15581da177e4SLinus Torvalds 1559d139d7ffSMiklos Szeredi error = do_truncate(dentry, 0, 1560d139d7ffSMiklos Szeredi ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, 1561d139d7ffSMiklos Szeredi NULL); 15621da177e4SLinus Torvalds } 15631da177e4SLinus Torvalds put_write_access(inode); 15641da177e4SLinus Torvalds if (error) 15651da177e4SLinus Torvalds return error; 15661da177e4SLinus Torvalds } else 15671da177e4SLinus Torvalds if (flag & FMODE_WRITE) 15681da177e4SLinus Torvalds DQUOT_INIT(inode); 15691da177e4SLinus Torvalds 15701da177e4SLinus Torvalds return 0; 15711da177e4SLinus Torvalds } 15721da177e4SLinus Torvalds 1573d57999e1SDave Hansen /* 1574d57999e1SDave Hansen * Be careful about ever adding any more callers of this 1575d57999e1SDave Hansen * function. Its flags must be in the namei format, not 1576d57999e1SDave Hansen * what get passed to sys_open(). 1577d57999e1SDave Hansen */ 1578d57999e1SDave Hansen static int __open_namei_create(struct nameidata *nd, struct path *path, 1579aab520e2SDave Hansen int flag, int mode) 1580aab520e2SDave Hansen { 1581aab520e2SDave Hansen int error; 15824ac91378SJan Blunck struct dentry *dir = nd->path.dentry; 1583aab520e2SDave Hansen 1584aab520e2SDave Hansen if (!IS_POSIXACL(dir->d_inode)) 1585aab520e2SDave Hansen mode &= ~current->fs->umask; 1586be6d3e56SKentaro Takeda error = security_path_mknod(&nd->path, path->dentry, mode, 0); 1587be6d3e56SKentaro Takeda if (error) 1588be6d3e56SKentaro Takeda goto out_unlock; 1589aab520e2SDave Hansen error = vfs_create(dir->d_inode, path->dentry, mode, nd); 1590be6d3e56SKentaro Takeda out_unlock: 1591aab520e2SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 15924ac91378SJan Blunck dput(nd->path.dentry); 15934ac91378SJan Blunck nd->path.dentry = path->dentry; 1594aab520e2SDave Hansen if (error) 1595aab520e2SDave Hansen return error; 1596aab520e2SDave Hansen /* Don't check for write permission, don't truncate */ 15973fb64190SChristoph Hellwig return may_open(&nd->path, 0, flag & ~O_TRUNC); 1598aab520e2SDave Hansen } 1599aab520e2SDave Hansen 16001da177e4SLinus Torvalds /* 1601d57999e1SDave Hansen * Note that while the flag value (low two bits) for sys_open means: 1602d57999e1SDave Hansen * 00 - read-only 1603d57999e1SDave Hansen * 01 - write-only 1604d57999e1SDave Hansen * 10 - read-write 1605d57999e1SDave Hansen * 11 - special 1606d57999e1SDave Hansen * it is changed into 1607d57999e1SDave Hansen * 00 - no permissions needed 1608d57999e1SDave Hansen * 01 - read-permission 1609d57999e1SDave Hansen * 10 - write-permission 1610d57999e1SDave Hansen * 11 - read-write 1611d57999e1SDave Hansen * for the internal routines (ie open_namei()/follow_link() etc) 1612d57999e1SDave Hansen * This is more logical, and also allows the 00 "no perm needed" 1613d57999e1SDave Hansen * to be used for symlinks (where the permissions are checked 1614d57999e1SDave Hansen * later). 1615d57999e1SDave Hansen * 1616d57999e1SDave Hansen */ 1617d57999e1SDave Hansen static inline int open_to_namei_flags(int flag) 1618d57999e1SDave Hansen { 1619d57999e1SDave Hansen if ((flag+1) & O_ACCMODE) 1620d57999e1SDave Hansen flag++; 1621d57999e1SDave Hansen return flag; 1622d57999e1SDave Hansen } 1623d57999e1SDave Hansen 16244a3fd211SDave Hansen static int open_will_write_to_fs(int flag, struct inode *inode) 16254a3fd211SDave Hansen { 1626d57999e1SDave Hansen /* 16274a3fd211SDave Hansen * We'll never write to the fs underlying 16284a3fd211SDave Hansen * a device file. 16294a3fd211SDave Hansen */ 16304a3fd211SDave Hansen if (special_file(inode->i_mode)) 16314a3fd211SDave Hansen return 0; 16324a3fd211SDave Hansen return (flag & O_TRUNC); 16334a3fd211SDave Hansen } 16344a3fd211SDave Hansen 16354a3fd211SDave Hansen /* 16364a3fd211SDave Hansen * Note that the low bits of the passed in "open_flag" 16374a3fd211SDave Hansen * are not the same as in the local variable "flag". See 16384a3fd211SDave Hansen * open_to_namei_flags() for more details. 16391da177e4SLinus Torvalds */ 1640a70e65dfSChristoph Hellwig struct file *do_filp_open(int dfd, const char *pathname, 1641a70e65dfSChristoph Hellwig int open_flag, int mode) 16421da177e4SLinus Torvalds { 16434a3fd211SDave Hansen struct file *filp; 1644a70e65dfSChristoph Hellwig struct nameidata nd; 1645834f2a4aSTrond Myklebust int acc_mode, error; 16464e7506e4SAl Viro struct path path; 16471da177e4SLinus Torvalds struct dentry *dir; 16481da177e4SLinus Torvalds int count = 0; 16494a3fd211SDave Hansen int will_write; 1650d57999e1SDave Hansen int flag = open_to_namei_flags(open_flag); 16511da177e4SLinus Torvalds 1652b77b0646SAl Viro acc_mode = MAY_OPEN | ACC_MODE(flag); 16531da177e4SLinus Torvalds 1654834f2a4aSTrond Myklebust /* O_TRUNC implies we need access checks for write permissions */ 1655834f2a4aSTrond Myklebust if (flag & O_TRUNC) 1656834f2a4aSTrond Myklebust acc_mode |= MAY_WRITE; 1657834f2a4aSTrond Myklebust 16581da177e4SLinus Torvalds /* Allow the LSM permission hook to distinguish append 16591da177e4SLinus Torvalds access from general write access. */ 16601da177e4SLinus Torvalds if (flag & O_APPEND) 16611da177e4SLinus Torvalds acc_mode |= MAY_APPEND; 16621da177e4SLinus Torvalds 16631da177e4SLinus Torvalds /* 16641da177e4SLinus Torvalds * The simplest case - just a plain lookup. 16651da177e4SLinus Torvalds */ 16661da177e4SLinus Torvalds if (!(flag & O_CREAT)) { 16675590ff0dSUlrich Drepper error = path_lookup_open(dfd, pathname, lookup_flags(flag), 1668a70e65dfSChristoph Hellwig &nd, flag); 16691da177e4SLinus Torvalds if (error) 1670a70e65dfSChristoph Hellwig return ERR_PTR(error); 16711da177e4SLinus Torvalds goto ok; 16721da177e4SLinus Torvalds } 16731da177e4SLinus Torvalds 16741da177e4SLinus Torvalds /* 16751da177e4SLinus Torvalds * Create - we need to know the parent. 16761da177e4SLinus Torvalds */ 16778737f3a1SAl Viro error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd); 16781da177e4SLinus Torvalds if (error) 1679a70e65dfSChristoph Hellwig return ERR_PTR(error); 16801da177e4SLinus Torvalds 16811da177e4SLinus Torvalds /* 16821da177e4SLinus Torvalds * We have the parent and last component. First of all, check 16831da177e4SLinus Torvalds * that we are not asked to creat(2) an obvious directory - that 16841da177e4SLinus Torvalds * will not do. 16851da177e4SLinus Torvalds */ 16861da177e4SLinus Torvalds error = -EISDIR; 1687a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM || nd.last.name[nd.last.len]) 16888737f3a1SAl Viro goto exit_parent; 16891da177e4SLinus Torvalds 16908737f3a1SAl Viro error = -ENFILE; 16918737f3a1SAl Viro filp = get_empty_filp(); 16928737f3a1SAl Viro if (filp == NULL) 16938737f3a1SAl Viro goto exit_parent; 16948737f3a1SAl Viro nd.intent.open.file = filp; 16958737f3a1SAl Viro nd.intent.open.flags = flag; 16968737f3a1SAl Viro nd.intent.open.create_mode = mode; 1697a70e65dfSChristoph Hellwig dir = nd.path.dentry; 1698a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 16998737f3a1SAl Viro nd.flags |= LOOKUP_CREATE | LOOKUP_OPEN; 17003516586aSAl Viro if (flag & O_EXCL) 17013516586aSAl Viro nd.flags |= LOOKUP_EXCL; 17021b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1703a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1704a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 17051da177e4SLinus Torvalds 17061da177e4SLinus Torvalds do_last: 17074e7506e4SAl Viro error = PTR_ERR(path.dentry); 17084e7506e4SAl Viro if (IS_ERR(path.dentry)) { 17091b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17101da177e4SLinus Torvalds goto exit; 17111da177e4SLinus Torvalds } 17121da177e4SLinus Torvalds 1713a70e65dfSChristoph Hellwig if (IS_ERR(nd.intent.open.file)) { 1714a70e65dfSChristoph Hellwig error = PTR_ERR(nd.intent.open.file); 17154a3fd211SDave Hansen goto exit_mutex_unlock; 17164af4c52fSOleg Drokin } 17174af4c52fSOleg Drokin 17181da177e4SLinus Torvalds /* Negative dentry, just create the file */ 17194e7506e4SAl Viro if (!path.dentry->d_inode) { 17204a3fd211SDave Hansen /* 17214a3fd211SDave Hansen * This write is needed to ensure that a 17224a3fd211SDave Hansen * ro->rw transition does not occur between 17234a3fd211SDave Hansen * the time when the file is created and when 17244a3fd211SDave Hansen * a permanent write count is taken through 17254a3fd211SDave Hansen * the 'struct file' in nameidata_to_filp(). 17264a3fd211SDave Hansen */ 17274a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17281da177e4SLinus Torvalds if (error) 17294a3fd211SDave Hansen goto exit_mutex_unlock; 17304a3fd211SDave Hansen error = __open_namei_create(&nd, &path, flag, mode); 17314a3fd211SDave Hansen if (error) { 17324a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17331da177e4SLinus Torvalds goto exit; 17344a3fd211SDave Hansen } 17354a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 17364a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17374a3fd211SDave Hansen return filp; 17381da177e4SLinus Torvalds } 17391da177e4SLinus Torvalds 17401da177e4SLinus Torvalds /* 17411da177e4SLinus Torvalds * It already exists. 17421da177e4SLinus Torvalds */ 17431b1dcc1bSJes Sorensen mutex_unlock(&dir->d_inode->i_mutex); 17445a190ae6SAl Viro audit_inode(pathname, path.dentry); 17451da177e4SLinus Torvalds 17461da177e4SLinus Torvalds error = -EEXIST; 17471da177e4SLinus Torvalds if (flag & O_EXCL) 17481da177e4SLinus Torvalds goto exit_dput; 17491da177e4SLinus Torvalds 1750e13b210fSAl Viro if (__follow_mount(&path)) { 17511da177e4SLinus Torvalds error = -ELOOP; 1752ba7a4c1aSAl Viro if (flag & O_NOFOLLOW) 1753ba7a4c1aSAl Viro goto exit_dput; 17541da177e4SLinus Torvalds } 17553e2efce0SAmy Griffis 17561da177e4SLinus Torvalds error = -ENOENT; 17574e7506e4SAl Viro if (!path.dentry->d_inode) 17581da177e4SLinus Torvalds goto exit_dput; 17594e7506e4SAl Viro if (path.dentry->d_inode->i_op && path.dentry->d_inode->i_op->follow_link) 17601da177e4SLinus Torvalds goto do_link; 17611da177e4SLinus Torvalds 1762a70e65dfSChristoph Hellwig path_to_nameidata(&path, &nd); 17631da177e4SLinus Torvalds error = -EISDIR; 17644e7506e4SAl Viro if (path.dentry->d_inode && S_ISDIR(path.dentry->d_inode->i_mode)) 17651da177e4SLinus Torvalds goto exit; 17661da177e4SLinus Torvalds ok: 17674a3fd211SDave Hansen /* 17684a3fd211SDave Hansen * Consider: 17694a3fd211SDave Hansen * 1. may_open() truncates a file 17704a3fd211SDave Hansen * 2. a rw->ro mount transition occurs 17714a3fd211SDave Hansen * 3. nameidata_to_filp() fails due to 17724a3fd211SDave Hansen * the ro mount. 17734a3fd211SDave Hansen * That would be inconsistent, and should 17744a3fd211SDave Hansen * be avoided. Taking this mnt write here 17754a3fd211SDave Hansen * ensures that (2) can not occur. 17764a3fd211SDave Hansen */ 17774a3fd211SDave Hansen will_write = open_will_write_to_fs(flag, nd.path.dentry->d_inode); 17784a3fd211SDave Hansen if (will_write) { 17794a3fd211SDave Hansen error = mnt_want_write(nd.path.mnt); 17801da177e4SLinus Torvalds if (error) 17811da177e4SLinus Torvalds goto exit; 17824a3fd211SDave Hansen } 17833fb64190SChristoph Hellwig error = may_open(&nd.path, acc_mode, flag); 17844a3fd211SDave Hansen if (error) { 17854a3fd211SDave Hansen if (will_write) 17864a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17874a3fd211SDave Hansen goto exit; 17884a3fd211SDave Hansen } 17894a3fd211SDave Hansen filp = nameidata_to_filp(&nd, open_flag); 17904a3fd211SDave Hansen /* 17914a3fd211SDave Hansen * It is now safe to drop the mnt write 17924a3fd211SDave Hansen * because the filp has had a write taken 17934a3fd211SDave Hansen * on its behalf. 17944a3fd211SDave Hansen */ 17954a3fd211SDave Hansen if (will_write) 17964a3fd211SDave Hansen mnt_drop_write(nd.path.mnt); 17974a3fd211SDave Hansen return filp; 17981da177e4SLinus Torvalds 17994a3fd211SDave Hansen exit_mutex_unlock: 18004a3fd211SDave Hansen mutex_unlock(&dir->d_inode->i_mutex); 18011da177e4SLinus Torvalds exit_dput: 1802a70e65dfSChristoph Hellwig path_put_conditional(&path, &nd); 18031da177e4SLinus Torvalds exit: 1804a70e65dfSChristoph Hellwig if (!IS_ERR(nd.intent.open.file)) 1805a70e65dfSChristoph Hellwig release_open_intent(&nd); 18068737f3a1SAl Viro exit_parent: 1807a70e65dfSChristoph Hellwig path_put(&nd.path); 1808a70e65dfSChristoph Hellwig return ERR_PTR(error); 18091da177e4SLinus Torvalds 18101da177e4SLinus Torvalds do_link: 18111da177e4SLinus Torvalds error = -ELOOP; 18121da177e4SLinus Torvalds if (flag & O_NOFOLLOW) 18131da177e4SLinus Torvalds goto exit_dput; 18141da177e4SLinus Torvalds /* 18151da177e4SLinus Torvalds * This is subtle. Instead of calling do_follow_link() we do the 18161da177e4SLinus Torvalds * thing by hands. The reason is that this way we have zero link_count 18171da177e4SLinus Torvalds * and path_walk() (called from ->follow_link) honoring LOOKUP_PARENT. 18181da177e4SLinus Torvalds * After that we have the parent and last component, i.e. 18191da177e4SLinus Torvalds * we are in the same situation as after the first path_walk(). 18201da177e4SLinus Torvalds * Well, almost - if the last component is normal we get its copy 18211da177e4SLinus Torvalds * stored in nd->last.name and we will have to putname() it when we 18221da177e4SLinus Torvalds * are done. Procfs-like symlinks just set LAST_BIND. 18231da177e4SLinus Torvalds */ 1824a70e65dfSChristoph Hellwig nd.flags |= LOOKUP_PARENT; 1825a70e65dfSChristoph Hellwig error = security_inode_follow_link(path.dentry, &nd); 18261da177e4SLinus Torvalds if (error) 18271da177e4SLinus Torvalds goto exit_dput; 1828a70e65dfSChristoph Hellwig error = __do_follow_link(&path, &nd); 1829de459215SKirill Korotaev if (error) { 1830de459215SKirill Korotaev /* Does someone understand code flow here? Or it is only 1831de459215SKirill Korotaev * me so stupid? Anathema to whoever designed this non-sense 1832de459215SKirill Korotaev * with "intent.open". 1833de459215SKirill Korotaev */ 1834a70e65dfSChristoph Hellwig release_open_intent(&nd); 1835a70e65dfSChristoph Hellwig return ERR_PTR(error); 1836de459215SKirill Korotaev } 1837a70e65dfSChristoph Hellwig nd.flags &= ~LOOKUP_PARENT; 1838a70e65dfSChristoph Hellwig if (nd.last_type == LAST_BIND) 18391da177e4SLinus Torvalds goto ok; 18401da177e4SLinus Torvalds error = -EISDIR; 1841a70e65dfSChristoph Hellwig if (nd.last_type != LAST_NORM) 18421da177e4SLinus Torvalds goto exit; 1843a70e65dfSChristoph Hellwig if (nd.last.name[nd.last.len]) { 1844a70e65dfSChristoph Hellwig __putname(nd.last.name); 18451da177e4SLinus Torvalds goto exit; 18461da177e4SLinus Torvalds } 18471da177e4SLinus Torvalds error = -ELOOP; 18481da177e4SLinus Torvalds if (count++==32) { 1849a70e65dfSChristoph Hellwig __putname(nd.last.name); 18501da177e4SLinus Torvalds goto exit; 18511da177e4SLinus Torvalds } 1852a70e65dfSChristoph Hellwig dir = nd.path.dentry; 18531b1dcc1bSJes Sorensen mutex_lock(&dir->d_inode->i_mutex); 1854a70e65dfSChristoph Hellwig path.dentry = lookup_hash(&nd); 1855a70e65dfSChristoph Hellwig path.mnt = nd.path.mnt; 1856a70e65dfSChristoph Hellwig __putname(nd.last.name); 18571da177e4SLinus Torvalds goto do_last; 18581da177e4SLinus Torvalds } 18591da177e4SLinus Torvalds 18601da177e4SLinus Torvalds /** 1861a70e65dfSChristoph Hellwig * filp_open - open file and return file pointer 1862a70e65dfSChristoph Hellwig * 1863a70e65dfSChristoph Hellwig * @filename: path to open 1864a70e65dfSChristoph Hellwig * @flags: open flags as per the open(2) second argument 1865a70e65dfSChristoph Hellwig * @mode: mode for the new file if O_CREAT is set, else ignored 1866a70e65dfSChristoph Hellwig * 1867a70e65dfSChristoph Hellwig * This is the helper to open a file from kernelspace if you really 1868a70e65dfSChristoph Hellwig * have to. But in generally you should not do this, so please move 1869a70e65dfSChristoph Hellwig * along, nothing to see here.. 1870a70e65dfSChristoph Hellwig */ 1871a70e65dfSChristoph Hellwig struct file *filp_open(const char *filename, int flags, int mode) 1872a70e65dfSChristoph Hellwig { 1873a70e65dfSChristoph Hellwig return do_filp_open(AT_FDCWD, filename, flags, mode); 1874a70e65dfSChristoph Hellwig } 1875a70e65dfSChristoph Hellwig EXPORT_SYMBOL(filp_open); 1876a70e65dfSChristoph Hellwig 1877a70e65dfSChristoph Hellwig /** 18781da177e4SLinus Torvalds * lookup_create - lookup a dentry, creating it if it doesn't exist 18791da177e4SLinus Torvalds * @nd: nameidata info 18801da177e4SLinus Torvalds * @is_dir: directory flag 18811da177e4SLinus Torvalds * 18821da177e4SLinus Torvalds * Simple function to lookup and return a dentry and create it 18831da177e4SLinus Torvalds * if it doesn't exist. Is SMP-safe. 1884c663e5d8SChristoph Hellwig * 18854ac91378SJan Blunck * Returns with nd->path.dentry->d_inode->i_mutex locked. 18861da177e4SLinus Torvalds */ 18871da177e4SLinus Torvalds struct dentry *lookup_create(struct nameidata *nd, int is_dir) 18881da177e4SLinus Torvalds { 1889c663e5d8SChristoph Hellwig struct dentry *dentry = ERR_PTR(-EEXIST); 18901da177e4SLinus Torvalds 18914ac91378SJan Blunck mutex_lock_nested(&nd->path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 1892c663e5d8SChristoph Hellwig /* 1893c663e5d8SChristoph Hellwig * Yucky last component or no last component at all? 1894c663e5d8SChristoph Hellwig * (foo/., foo/.., /////) 1895c663e5d8SChristoph Hellwig */ 18961da177e4SLinus Torvalds if (nd->last_type != LAST_NORM) 18971da177e4SLinus Torvalds goto fail; 18981da177e4SLinus Torvalds nd->flags &= ~LOOKUP_PARENT; 18993516586aSAl Viro nd->flags |= LOOKUP_CREATE | LOOKUP_EXCL; 1900a634904aSASANO Masahiro nd->intent.open.flags = O_EXCL; 1901c663e5d8SChristoph Hellwig 1902c663e5d8SChristoph Hellwig /* 1903c663e5d8SChristoph Hellwig * Do the final lookup. 1904c663e5d8SChristoph Hellwig */ 190549705b77SChristoph Hellwig dentry = lookup_hash(nd); 19061da177e4SLinus Torvalds if (IS_ERR(dentry)) 19071da177e4SLinus Torvalds goto fail; 1908c663e5d8SChristoph Hellwig 1909e9baf6e5SAl Viro if (dentry->d_inode) 1910e9baf6e5SAl Viro goto eexist; 1911c663e5d8SChristoph Hellwig /* 1912c663e5d8SChristoph Hellwig * Special case - lookup gave negative, but... we had foo/bar/ 1913c663e5d8SChristoph Hellwig * From the vfs_mknod() POV we just have a negative dentry - 1914c663e5d8SChristoph Hellwig * all is fine. Let's be bastards - you had / on the end, you've 1915c663e5d8SChristoph Hellwig * been asking for (non-existent) directory. -ENOENT for you. 1916c663e5d8SChristoph Hellwig */ 1917e9baf6e5SAl Viro if (unlikely(!is_dir && nd->last.name[nd->last.len])) { 19181da177e4SLinus Torvalds dput(dentry); 19191da177e4SLinus Torvalds dentry = ERR_PTR(-ENOENT); 1920e9baf6e5SAl Viro } 1921e9baf6e5SAl Viro return dentry; 1922e9baf6e5SAl Viro eexist: 1923e9baf6e5SAl Viro dput(dentry); 1924e9baf6e5SAl Viro dentry = ERR_PTR(-EEXIST); 19251da177e4SLinus Torvalds fail: 19261da177e4SLinus Torvalds return dentry; 19271da177e4SLinus Torvalds } 1928f81a0bffSChristoph Hellwig EXPORT_SYMBOL_GPL(lookup_create); 19291da177e4SLinus Torvalds 19301da177e4SLinus Torvalds int vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) 19311da177e4SLinus Torvalds { 1932a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 19331da177e4SLinus Torvalds 19341da177e4SLinus Torvalds if (error) 19351da177e4SLinus Torvalds return error; 19361da177e4SLinus Torvalds 19371da177e4SLinus Torvalds if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) 19381da177e4SLinus Torvalds return -EPERM; 19391da177e4SLinus Torvalds 19401da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->mknod) 19411da177e4SLinus Torvalds return -EPERM; 19421da177e4SLinus Torvalds 194308ce5f16SSerge E. Hallyn error = devcgroup_inode_mknod(mode, dev); 194408ce5f16SSerge E. Hallyn if (error) 194508ce5f16SSerge E. Hallyn return error; 194608ce5f16SSerge E. Hallyn 19471da177e4SLinus Torvalds error = security_inode_mknod(dir, dentry, mode, dev); 19481da177e4SLinus Torvalds if (error) 19491da177e4SLinus Torvalds return error; 19501da177e4SLinus Torvalds 19511da177e4SLinus Torvalds DQUOT_INIT(dir); 19521da177e4SLinus Torvalds error = dir->i_op->mknod(dir, dentry, mode, dev); 1953a74574aaSStephen Smalley if (!error) 1954f38aa942SAmy Griffis fsnotify_create(dir, dentry); 19551da177e4SLinus Torvalds return error; 19561da177e4SLinus Torvalds } 19571da177e4SLinus Torvalds 1958463c3197SDave Hansen static int may_mknod(mode_t mode) 1959463c3197SDave Hansen { 1960463c3197SDave Hansen switch (mode & S_IFMT) { 1961463c3197SDave Hansen case S_IFREG: 1962463c3197SDave Hansen case S_IFCHR: 1963463c3197SDave Hansen case S_IFBLK: 1964463c3197SDave Hansen case S_IFIFO: 1965463c3197SDave Hansen case S_IFSOCK: 1966463c3197SDave Hansen case 0: /* zero mode translates to S_IFREG */ 1967463c3197SDave Hansen return 0; 1968463c3197SDave Hansen case S_IFDIR: 1969463c3197SDave Hansen return -EPERM; 1970463c3197SDave Hansen default: 1971463c3197SDave Hansen return -EINVAL; 1972463c3197SDave Hansen } 1973463c3197SDave Hansen } 1974463c3197SDave Hansen 19755590ff0dSUlrich Drepper asmlinkage long sys_mknodat(int dfd, const char __user *filename, int mode, 19765590ff0dSUlrich Drepper unsigned dev) 19771da177e4SLinus Torvalds { 19782ad94ae6SAl Viro int error; 19791da177e4SLinus Torvalds char *tmp; 19801da177e4SLinus Torvalds struct dentry *dentry; 19811da177e4SLinus Torvalds struct nameidata nd; 19821da177e4SLinus Torvalds 19831da177e4SLinus Torvalds if (S_ISDIR(mode)) 19841da177e4SLinus Torvalds return -EPERM; 19851da177e4SLinus Torvalds 19862ad94ae6SAl Viro error = user_path_parent(dfd, filename, &nd, &tmp); 19871da177e4SLinus Torvalds if (error) 19882ad94ae6SAl Viro return error; 19892ad94ae6SAl Viro 19901da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 1991463c3197SDave Hansen if (IS_ERR(dentry)) { 19921da177e4SLinus Torvalds error = PTR_ERR(dentry); 1993463c3197SDave Hansen goto out_unlock; 1994463c3197SDave Hansen } 19954ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 19961da177e4SLinus Torvalds mode &= ~current->fs->umask; 1997463c3197SDave Hansen error = may_mknod(mode); 1998463c3197SDave Hansen if (error) 1999463c3197SDave Hansen goto out_dput; 2000463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2001463c3197SDave Hansen if (error) 2002463c3197SDave Hansen goto out_dput; 2003be6d3e56SKentaro Takeda error = security_path_mknod(&nd.path, dentry, mode, dev); 2004be6d3e56SKentaro Takeda if (error) 2005be6d3e56SKentaro Takeda goto out_drop_write; 20061da177e4SLinus Torvalds switch (mode & S_IFMT) { 20071da177e4SLinus Torvalds case 0: case S_IFREG: 20084ac91378SJan Blunck error = vfs_create(nd.path.dentry->d_inode,dentry,mode,&nd); 20091da177e4SLinus Torvalds break; 20101da177e4SLinus Torvalds case S_IFCHR: case S_IFBLK: 20114ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode, 20121da177e4SLinus Torvalds new_decode_dev(dev)); 20131da177e4SLinus Torvalds break; 20141da177e4SLinus Torvalds case S_IFIFO: case S_IFSOCK: 20154ac91378SJan Blunck error = vfs_mknod(nd.path.dentry->d_inode,dentry,mode,0); 20161da177e4SLinus Torvalds break; 20171da177e4SLinus Torvalds } 2018be6d3e56SKentaro Takeda out_drop_write: 2019463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2020463c3197SDave Hansen out_dput: 20211da177e4SLinus Torvalds dput(dentry); 2022463c3197SDave Hansen out_unlock: 20234ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20241d957f9bSJan Blunck path_put(&nd.path); 20251da177e4SLinus Torvalds putname(tmp); 20261da177e4SLinus Torvalds 20271da177e4SLinus Torvalds return error; 20281da177e4SLinus Torvalds } 20291da177e4SLinus Torvalds 20305590ff0dSUlrich Drepper asmlinkage long sys_mknod(const char __user *filename, int mode, unsigned dev) 20315590ff0dSUlrich Drepper { 20325590ff0dSUlrich Drepper return sys_mknodat(AT_FDCWD, filename, mode, dev); 20335590ff0dSUlrich Drepper } 20345590ff0dSUlrich Drepper 20351da177e4SLinus Torvalds int vfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) 20361da177e4SLinus Torvalds { 2037a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 20381da177e4SLinus Torvalds 20391da177e4SLinus Torvalds if (error) 20401da177e4SLinus Torvalds return error; 20411da177e4SLinus Torvalds 20421da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->mkdir) 20431da177e4SLinus Torvalds return -EPERM; 20441da177e4SLinus Torvalds 20451da177e4SLinus Torvalds mode &= (S_IRWXUGO|S_ISVTX); 20461da177e4SLinus Torvalds error = security_inode_mkdir(dir, dentry, mode); 20471da177e4SLinus Torvalds if (error) 20481da177e4SLinus Torvalds return error; 20491da177e4SLinus Torvalds 20501da177e4SLinus Torvalds DQUOT_INIT(dir); 20511da177e4SLinus Torvalds error = dir->i_op->mkdir(dir, dentry, mode); 2052a74574aaSStephen Smalley if (!error) 2053f38aa942SAmy Griffis fsnotify_mkdir(dir, dentry); 20541da177e4SLinus Torvalds return error; 20551da177e4SLinus Torvalds } 20561da177e4SLinus Torvalds 20575590ff0dSUlrich Drepper asmlinkage long sys_mkdirat(int dfd, const char __user *pathname, int mode) 20581da177e4SLinus Torvalds { 20591da177e4SLinus Torvalds int error = 0; 20601da177e4SLinus Torvalds char * tmp; 20616902d925SDave Hansen struct dentry *dentry; 20626902d925SDave Hansen struct nameidata nd; 20631da177e4SLinus Torvalds 20642ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &tmp); 20652ad94ae6SAl Viro if (error) 20666902d925SDave Hansen goto out_err; 20671da177e4SLinus Torvalds 20681da177e4SLinus Torvalds dentry = lookup_create(&nd, 1); 20691da177e4SLinus Torvalds error = PTR_ERR(dentry); 20706902d925SDave Hansen if (IS_ERR(dentry)) 20716902d925SDave Hansen goto out_unlock; 20726902d925SDave Hansen 20734ac91378SJan Blunck if (!IS_POSIXACL(nd.path.dentry->d_inode)) 20741da177e4SLinus Torvalds mode &= ~current->fs->umask; 2075463c3197SDave Hansen error = mnt_want_write(nd.path.mnt); 2076463c3197SDave Hansen if (error) 2077463c3197SDave Hansen goto out_dput; 2078be6d3e56SKentaro Takeda error = security_path_mkdir(&nd.path, dentry, mode); 2079be6d3e56SKentaro Takeda if (error) 2080be6d3e56SKentaro Takeda goto out_drop_write; 20814ac91378SJan Blunck error = vfs_mkdir(nd.path.dentry->d_inode, dentry, mode); 2082be6d3e56SKentaro Takeda out_drop_write: 2083463c3197SDave Hansen mnt_drop_write(nd.path.mnt); 2084463c3197SDave Hansen out_dput: 20851da177e4SLinus Torvalds dput(dentry); 20866902d925SDave Hansen out_unlock: 20874ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 20881d957f9bSJan Blunck path_put(&nd.path); 20891da177e4SLinus Torvalds putname(tmp); 20906902d925SDave Hansen out_err: 20911da177e4SLinus Torvalds return error; 20921da177e4SLinus Torvalds } 20931da177e4SLinus Torvalds 20945590ff0dSUlrich Drepper asmlinkage long sys_mkdir(const char __user *pathname, int mode) 20955590ff0dSUlrich Drepper { 20965590ff0dSUlrich Drepper return sys_mkdirat(AT_FDCWD, pathname, mode); 20975590ff0dSUlrich Drepper } 20985590ff0dSUlrich Drepper 20991da177e4SLinus Torvalds /* 21001da177e4SLinus Torvalds * We try to drop the dentry early: we should have 21011da177e4SLinus Torvalds * a usage count of 2 if we're the only user of this 21021da177e4SLinus Torvalds * dentry, and if that is true (possibly after pruning 21031da177e4SLinus Torvalds * the dcache), then we drop the dentry now. 21041da177e4SLinus Torvalds * 21051da177e4SLinus Torvalds * A low-level filesystem can, if it choses, legally 21061da177e4SLinus Torvalds * do a 21071da177e4SLinus Torvalds * 21081da177e4SLinus Torvalds * if (!d_unhashed(dentry)) 21091da177e4SLinus Torvalds * return -EBUSY; 21101da177e4SLinus Torvalds * 21111da177e4SLinus Torvalds * if it cannot handle the case of removing a directory 21121da177e4SLinus Torvalds * that is still in use by something else.. 21131da177e4SLinus Torvalds */ 21141da177e4SLinus Torvalds void dentry_unhash(struct dentry *dentry) 21151da177e4SLinus Torvalds { 21161da177e4SLinus Torvalds dget(dentry); 21171da177e4SLinus Torvalds shrink_dcache_parent(dentry); 21181da177e4SLinus Torvalds spin_lock(&dcache_lock); 21191da177e4SLinus Torvalds spin_lock(&dentry->d_lock); 21201da177e4SLinus Torvalds if (atomic_read(&dentry->d_count) == 2) 21211da177e4SLinus Torvalds __d_drop(dentry); 21221da177e4SLinus Torvalds spin_unlock(&dentry->d_lock); 21231da177e4SLinus Torvalds spin_unlock(&dcache_lock); 21241da177e4SLinus Torvalds } 21251da177e4SLinus Torvalds 21261da177e4SLinus Torvalds int vfs_rmdir(struct inode *dir, struct dentry *dentry) 21271da177e4SLinus Torvalds { 21281da177e4SLinus Torvalds int error = may_delete(dir, dentry, 1); 21291da177e4SLinus Torvalds 21301da177e4SLinus Torvalds if (error) 21311da177e4SLinus Torvalds return error; 21321da177e4SLinus Torvalds 21331da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->rmdir) 21341da177e4SLinus Torvalds return -EPERM; 21351da177e4SLinus Torvalds 21361da177e4SLinus Torvalds DQUOT_INIT(dir); 21371da177e4SLinus Torvalds 21381b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 21391da177e4SLinus Torvalds dentry_unhash(dentry); 21401da177e4SLinus Torvalds if (d_mountpoint(dentry)) 21411da177e4SLinus Torvalds error = -EBUSY; 21421da177e4SLinus Torvalds else { 21431da177e4SLinus Torvalds error = security_inode_rmdir(dir, dentry); 21441da177e4SLinus Torvalds if (!error) { 21451da177e4SLinus Torvalds error = dir->i_op->rmdir(dir, dentry); 21461da177e4SLinus Torvalds if (!error) 21471da177e4SLinus Torvalds dentry->d_inode->i_flags |= S_DEAD; 21481da177e4SLinus Torvalds } 21491da177e4SLinus Torvalds } 21501b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 21511da177e4SLinus Torvalds if (!error) { 21521da177e4SLinus Torvalds d_delete(dentry); 21531da177e4SLinus Torvalds } 21541da177e4SLinus Torvalds dput(dentry); 21551da177e4SLinus Torvalds 21561da177e4SLinus Torvalds return error; 21571da177e4SLinus Torvalds } 21581da177e4SLinus Torvalds 21595590ff0dSUlrich Drepper static long do_rmdir(int dfd, const char __user *pathname) 21601da177e4SLinus Torvalds { 21611da177e4SLinus Torvalds int error = 0; 21621da177e4SLinus Torvalds char * name; 21631da177e4SLinus Torvalds struct dentry *dentry; 21641da177e4SLinus Torvalds struct nameidata nd; 21651da177e4SLinus Torvalds 21662ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 21671da177e4SLinus Torvalds if (error) 21682ad94ae6SAl Viro return error; 21691da177e4SLinus Torvalds 21701da177e4SLinus Torvalds switch(nd.last_type) { 21711da177e4SLinus Torvalds case LAST_DOTDOT: 21721da177e4SLinus Torvalds error = -ENOTEMPTY; 21731da177e4SLinus Torvalds goto exit1; 21741da177e4SLinus Torvalds case LAST_DOT: 21751da177e4SLinus Torvalds error = -EINVAL; 21761da177e4SLinus Torvalds goto exit1; 21771da177e4SLinus Torvalds case LAST_ROOT: 21781da177e4SLinus Torvalds error = -EBUSY; 21791da177e4SLinus Torvalds goto exit1; 21801da177e4SLinus Torvalds } 21810612d9fbSOGAWA Hirofumi 21820612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 21830612d9fbSOGAWA Hirofumi 21844ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 218549705b77SChristoph Hellwig dentry = lookup_hash(&nd); 21861da177e4SLinus Torvalds error = PTR_ERR(dentry); 21876902d925SDave Hansen if (IS_ERR(dentry)) 21886902d925SDave Hansen goto exit2; 21890622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 21900622753bSDave Hansen if (error) 21910622753bSDave Hansen goto exit3; 2192be6d3e56SKentaro Takeda error = security_path_rmdir(&nd.path, dentry); 2193be6d3e56SKentaro Takeda if (error) 2194be6d3e56SKentaro Takeda goto exit4; 21954ac91378SJan Blunck error = vfs_rmdir(nd.path.dentry->d_inode, dentry); 2196be6d3e56SKentaro Takeda exit4: 21970622753bSDave Hansen mnt_drop_write(nd.path.mnt); 21980622753bSDave Hansen exit3: 21991da177e4SLinus Torvalds dput(dentry); 22006902d925SDave Hansen exit2: 22014ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22021da177e4SLinus Torvalds exit1: 22031d957f9bSJan Blunck path_put(&nd.path); 22041da177e4SLinus Torvalds putname(name); 22051da177e4SLinus Torvalds return error; 22061da177e4SLinus Torvalds } 22071da177e4SLinus Torvalds 22085590ff0dSUlrich Drepper asmlinkage long sys_rmdir(const char __user *pathname) 22095590ff0dSUlrich Drepper { 22105590ff0dSUlrich Drepper return do_rmdir(AT_FDCWD, pathname); 22115590ff0dSUlrich Drepper } 22125590ff0dSUlrich Drepper 22131da177e4SLinus Torvalds int vfs_unlink(struct inode *dir, struct dentry *dentry) 22141da177e4SLinus Torvalds { 22151da177e4SLinus Torvalds int error = may_delete(dir, dentry, 0); 22161da177e4SLinus Torvalds 22171da177e4SLinus Torvalds if (error) 22181da177e4SLinus Torvalds return error; 22191da177e4SLinus Torvalds 22201da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->unlink) 22211da177e4SLinus Torvalds return -EPERM; 22221da177e4SLinus Torvalds 22231da177e4SLinus Torvalds DQUOT_INIT(dir); 22241da177e4SLinus Torvalds 22251b1dcc1bSJes Sorensen mutex_lock(&dentry->d_inode->i_mutex); 22261da177e4SLinus Torvalds if (d_mountpoint(dentry)) 22271da177e4SLinus Torvalds error = -EBUSY; 22281da177e4SLinus Torvalds else { 22291da177e4SLinus Torvalds error = security_inode_unlink(dir, dentry); 22301da177e4SLinus Torvalds if (!error) 22311da177e4SLinus Torvalds error = dir->i_op->unlink(dir, dentry); 22321da177e4SLinus Torvalds } 22331b1dcc1bSJes Sorensen mutex_unlock(&dentry->d_inode->i_mutex); 22341da177e4SLinus Torvalds 22351da177e4SLinus Torvalds /* We don't d_delete() NFS sillyrenamed files--they still exist. */ 22361da177e4SLinus Torvalds if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { 2237ece95912SJan Kara fsnotify_link_count(dentry->d_inode); 22381da177e4SLinus Torvalds d_delete(dentry); 22391da177e4SLinus Torvalds } 22400eeca283SRobert Love 22411da177e4SLinus Torvalds return error; 22421da177e4SLinus Torvalds } 22431da177e4SLinus Torvalds 22441da177e4SLinus Torvalds /* 22451da177e4SLinus Torvalds * Make sure that the actual truncation of the file will occur outside its 22461b1dcc1bSJes Sorensen * directory's i_mutex. Truncate can take a long time if there is a lot of 22471da177e4SLinus Torvalds * writeout happening, and we don't want to prevent access to the directory 22481da177e4SLinus Torvalds * while waiting on the I/O. 22491da177e4SLinus Torvalds */ 22505590ff0dSUlrich Drepper static long do_unlinkat(int dfd, const char __user *pathname) 22511da177e4SLinus Torvalds { 22522ad94ae6SAl Viro int error; 22531da177e4SLinus Torvalds char *name; 22541da177e4SLinus Torvalds struct dentry *dentry; 22551da177e4SLinus Torvalds struct nameidata nd; 22561da177e4SLinus Torvalds struct inode *inode = NULL; 22571da177e4SLinus Torvalds 22582ad94ae6SAl Viro error = user_path_parent(dfd, pathname, &nd, &name); 22591da177e4SLinus Torvalds if (error) 22602ad94ae6SAl Viro return error; 22612ad94ae6SAl Viro 22621da177e4SLinus Torvalds error = -EISDIR; 22631da177e4SLinus Torvalds if (nd.last_type != LAST_NORM) 22641da177e4SLinus Torvalds goto exit1; 22650612d9fbSOGAWA Hirofumi 22660612d9fbSOGAWA Hirofumi nd.flags &= ~LOOKUP_PARENT; 22670612d9fbSOGAWA Hirofumi 22684ac91378SJan Blunck mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); 226949705b77SChristoph Hellwig dentry = lookup_hash(&nd); 22701da177e4SLinus Torvalds error = PTR_ERR(dentry); 22711da177e4SLinus Torvalds if (!IS_ERR(dentry)) { 22721da177e4SLinus Torvalds /* Why not before? Because we want correct error value */ 22731da177e4SLinus Torvalds if (nd.last.name[nd.last.len]) 22741da177e4SLinus Torvalds goto slashes; 22751da177e4SLinus Torvalds inode = dentry->d_inode; 22761da177e4SLinus Torvalds if (inode) 22771da177e4SLinus Torvalds atomic_inc(&inode->i_count); 22780622753bSDave Hansen error = mnt_want_write(nd.path.mnt); 22790622753bSDave Hansen if (error) 22800622753bSDave Hansen goto exit2; 2281be6d3e56SKentaro Takeda error = security_path_unlink(&nd.path, dentry); 2282be6d3e56SKentaro Takeda if (error) 2283be6d3e56SKentaro Takeda goto exit3; 22844ac91378SJan Blunck error = vfs_unlink(nd.path.dentry->d_inode, dentry); 2285be6d3e56SKentaro Takeda exit3: 22860622753bSDave Hansen mnt_drop_write(nd.path.mnt); 22871da177e4SLinus Torvalds exit2: 22881da177e4SLinus Torvalds dput(dentry); 22891da177e4SLinus Torvalds } 22904ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 22911da177e4SLinus Torvalds if (inode) 22921da177e4SLinus Torvalds iput(inode); /* truncate the inode here */ 22931da177e4SLinus Torvalds exit1: 22941d957f9bSJan Blunck path_put(&nd.path); 22951da177e4SLinus Torvalds putname(name); 22961da177e4SLinus Torvalds return error; 22971da177e4SLinus Torvalds 22981da177e4SLinus Torvalds slashes: 22991da177e4SLinus Torvalds error = !dentry->d_inode ? -ENOENT : 23001da177e4SLinus Torvalds S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; 23011da177e4SLinus Torvalds goto exit2; 23021da177e4SLinus Torvalds } 23031da177e4SLinus Torvalds 23045590ff0dSUlrich Drepper asmlinkage long sys_unlinkat(int dfd, const char __user *pathname, int flag) 23055590ff0dSUlrich Drepper { 23065590ff0dSUlrich Drepper if ((flag & ~AT_REMOVEDIR) != 0) 23075590ff0dSUlrich Drepper return -EINVAL; 23085590ff0dSUlrich Drepper 23095590ff0dSUlrich Drepper if (flag & AT_REMOVEDIR) 23105590ff0dSUlrich Drepper return do_rmdir(dfd, pathname); 23115590ff0dSUlrich Drepper 23125590ff0dSUlrich Drepper return do_unlinkat(dfd, pathname); 23135590ff0dSUlrich Drepper } 23145590ff0dSUlrich Drepper 23155590ff0dSUlrich Drepper asmlinkage long sys_unlink(const char __user *pathname) 23165590ff0dSUlrich Drepper { 23175590ff0dSUlrich Drepper return do_unlinkat(AT_FDCWD, pathname); 23185590ff0dSUlrich Drepper } 23195590ff0dSUlrich Drepper 2320db2e747bSMiklos Szeredi int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) 23211da177e4SLinus Torvalds { 2322a95164d9SMiklos Szeredi int error = may_create(dir, dentry); 23231da177e4SLinus Torvalds 23241da177e4SLinus Torvalds if (error) 23251da177e4SLinus Torvalds return error; 23261da177e4SLinus Torvalds 23271da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->symlink) 23281da177e4SLinus Torvalds return -EPERM; 23291da177e4SLinus Torvalds 23301da177e4SLinus Torvalds error = security_inode_symlink(dir, dentry, oldname); 23311da177e4SLinus Torvalds if (error) 23321da177e4SLinus Torvalds return error; 23331da177e4SLinus Torvalds 23341da177e4SLinus Torvalds DQUOT_INIT(dir); 23351da177e4SLinus Torvalds error = dir->i_op->symlink(dir, dentry, oldname); 2336a74574aaSStephen Smalley if (!error) 2337f38aa942SAmy Griffis fsnotify_create(dir, dentry); 23381da177e4SLinus Torvalds return error; 23391da177e4SLinus Torvalds } 23401da177e4SLinus Torvalds 23415590ff0dSUlrich Drepper asmlinkage long sys_symlinkat(const char __user *oldname, 23425590ff0dSUlrich Drepper int newdfd, const char __user *newname) 23431da177e4SLinus Torvalds { 23442ad94ae6SAl Viro int error; 23451da177e4SLinus Torvalds char *from; 23461da177e4SLinus Torvalds char *to; 23476902d925SDave Hansen struct dentry *dentry; 23486902d925SDave Hansen struct nameidata nd; 23491da177e4SLinus Torvalds 23501da177e4SLinus Torvalds from = getname(oldname); 23511da177e4SLinus Torvalds if (IS_ERR(from)) 23521da177e4SLinus Torvalds return PTR_ERR(from); 23532ad94ae6SAl Viro 23542ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 23552ad94ae6SAl Viro if (error) 23566902d925SDave Hansen goto out_putname; 23571da177e4SLinus Torvalds 23581da177e4SLinus Torvalds dentry = lookup_create(&nd, 0); 23591da177e4SLinus Torvalds error = PTR_ERR(dentry); 23606902d925SDave Hansen if (IS_ERR(dentry)) 23616902d925SDave Hansen goto out_unlock; 23626902d925SDave Hansen 236375c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 236475c3f29dSDave Hansen if (error) 236575c3f29dSDave Hansen goto out_dput; 2366be6d3e56SKentaro Takeda error = security_path_symlink(&nd.path, dentry, from); 2367be6d3e56SKentaro Takeda if (error) 2368be6d3e56SKentaro Takeda goto out_drop_write; 2369db2e747bSMiklos Szeredi error = vfs_symlink(nd.path.dentry->d_inode, dentry, from); 2370be6d3e56SKentaro Takeda out_drop_write: 237175c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 237275c3f29dSDave Hansen out_dput: 23731da177e4SLinus Torvalds dput(dentry); 23746902d925SDave Hansen out_unlock: 23754ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 23761d957f9bSJan Blunck path_put(&nd.path); 23771da177e4SLinus Torvalds putname(to); 23786902d925SDave Hansen out_putname: 23791da177e4SLinus Torvalds putname(from); 23801da177e4SLinus Torvalds return error; 23811da177e4SLinus Torvalds } 23821da177e4SLinus Torvalds 23835590ff0dSUlrich Drepper asmlinkage long sys_symlink(const char __user *oldname, const char __user *newname) 23845590ff0dSUlrich Drepper { 23855590ff0dSUlrich Drepper return sys_symlinkat(oldname, AT_FDCWD, newname); 23865590ff0dSUlrich Drepper } 23875590ff0dSUlrich Drepper 23881da177e4SLinus Torvalds int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) 23891da177e4SLinus Torvalds { 23901da177e4SLinus Torvalds struct inode *inode = old_dentry->d_inode; 23911da177e4SLinus Torvalds int error; 23921da177e4SLinus Torvalds 23931da177e4SLinus Torvalds if (!inode) 23941da177e4SLinus Torvalds return -ENOENT; 23951da177e4SLinus Torvalds 2396a95164d9SMiklos Szeredi error = may_create(dir, new_dentry); 23971da177e4SLinus Torvalds if (error) 23981da177e4SLinus Torvalds return error; 23991da177e4SLinus Torvalds 24001da177e4SLinus Torvalds if (dir->i_sb != inode->i_sb) 24011da177e4SLinus Torvalds return -EXDEV; 24021da177e4SLinus Torvalds 24031da177e4SLinus Torvalds /* 24041da177e4SLinus Torvalds * A link to an append-only or immutable file cannot be created. 24051da177e4SLinus Torvalds */ 24061da177e4SLinus Torvalds if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) 24071da177e4SLinus Torvalds return -EPERM; 24081da177e4SLinus Torvalds if (!dir->i_op || !dir->i_op->link) 24091da177e4SLinus Torvalds return -EPERM; 24107e79eedbSTetsuo Handa if (S_ISDIR(inode->i_mode)) 24111da177e4SLinus Torvalds return -EPERM; 24121da177e4SLinus Torvalds 24131da177e4SLinus Torvalds error = security_inode_link(old_dentry, dir, new_dentry); 24141da177e4SLinus Torvalds if (error) 24151da177e4SLinus Torvalds return error; 24161da177e4SLinus Torvalds 24177e79eedbSTetsuo Handa mutex_lock(&inode->i_mutex); 24181da177e4SLinus Torvalds DQUOT_INIT(dir); 24191da177e4SLinus Torvalds error = dir->i_op->link(old_dentry, dir, new_dentry); 24207e79eedbSTetsuo Handa mutex_unlock(&inode->i_mutex); 2421e31e14ecSStephen Smalley if (!error) 24227e79eedbSTetsuo Handa fsnotify_link(dir, inode, new_dentry); 24231da177e4SLinus Torvalds return error; 24241da177e4SLinus Torvalds } 24251da177e4SLinus Torvalds 24261da177e4SLinus Torvalds /* 24271da177e4SLinus Torvalds * Hardlinks are often used in delicate situations. We avoid 24281da177e4SLinus Torvalds * security-related surprises by not following symlinks on the 24291da177e4SLinus Torvalds * newname. --KAB 24301da177e4SLinus Torvalds * 24311da177e4SLinus Torvalds * We don't follow them on the oldname either to be compatible 24321da177e4SLinus Torvalds * with linux 2.0, and to avoid hard-linking to directories 24331da177e4SLinus Torvalds * and other special files. --ADM 24341da177e4SLinus Torvalds */ 24355590ff0dSUlrich Drepper asmlinkage long sys_linkat(int olddfd, const char __user *oldname, 2436c04030e1SUlrich Drepper int newdfd, const char __user *newname, 2437c04030e1SUlrich Drepper int flags) 24381da177e4SLinus Torvalds { 24391da177e4SLinus Torvalds struct dentry *new_dentry; 24402d8f3038SAl Viro struct nameidata nd; 24412d8f3038SAl Viro struct path old_path; 24421da177e4SLinus Torvalds int error; 24431da177e4SLinus Torvalds char *to; 24441da177e4SLinus Torvalds 244545c9b11aSUlrich Drepper if ((flags & ~AT_SYMLINK_FOLLOW) != 0) 2446c04030e1SUlrich Drepper return -EINVAL; 2447c04030e1SUlrich Drepper 24482d8f3038SAl Viro error = user_path_at(olddfd, oldname, 244945c9b11aSUlrich Drepper flags & AT_SYMLINK_FOLLOW ? LOOKUP_FOLLOW : 0, 24502d8f3038SAl Viro &old_path); 24511da177e4SLinus Torvalds if (error) 24522ad94ae6SAl Viro return error; 24532ad94ae6SAl Viro 24542ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &nd, &to); 24551da177e4SLinus Torvalds if (error) 24561da177e4SLinus Torvalds goto out; 24571da177e4SLinus Torvalds error = -EXDEV; 24582d8f3038SAl Viro if (old_path.mnt != nd.path.mnt) 24591da177e4SLinus Torvalds goto out_release; 24601da177e4SLinus Torvalds new_dentry = lookup_create(&nd, 0); 24611da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 24626902d925SDave Hansen if (IS_ERR(new_dentry)) 24636902d925SDave Hansen goto out_unlock; 246475c3f29dSDave Hansen error = mnt_want_write(nd.path.mnt); 246575c3f29dSDave Hansen if (error) 246675c3f29dSDave Hansen goto out_dput; 2467be6d3e56SKentaro Takeda error = security_path_link(old_path.dentry, &nd.path, new_dentry); 2468be6d3e56SKentaro Takeda if (error) 2469be6d3e56SKentaro Takeda goto out_drop_write; 24702d8f3038SAl Viro error = vfs_link(old_path.dentry, nd.path.dentry->d_inode, new_dentry); 2471be6d3e56SKentaro Takeda out_drop_write: 247275c3f29dSDave Hansen mnt_drop_write(nd.path.mnt); 247375c3f29dSDave Hansen out_dput: 24741da177e4SLinus Torvalds dput(new_dentry); 24756902d925SDave Hansen out_unlock: 24764ac91378SJan Blunck mutex_unlock(&nd.path.dentry->d_inode->i_mutex); 24771da177e4SLinus Torvalds out_release: 24781d957f9bSJan Blunck path_put(&nd.path); 24792ad94ae6SAl Viro putname(to); 24801da177e4SLinus Torvalds out: 24812d8f3038SAl Viro path_put(&old_path); 24821da177e4SLinus Torvalds 24831da177e4SLinus Torvalds return error; 24841da177e4SLinus Torvalds } 24851da177e4SLinus Torvalds 24865590ff0dSUlrich Drepper asmlinkage long sys_link(const char __user *oldname, const char __user *newname) 24875590ff0dSUlrich Drepper { 2488c04030e1SUlrich Drepper return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); 24895590ff0dSUlrich Drepper } 24905590ff0dSUlrich Drepper 24911da177e4SLinus Torvalds /* 24921da177e4SLinus Torvalds * The worst of all namespace operations - renaming directory. "Perverted" 24931da177e4SLinus Torvalds * doesn't even start to describe it. Somebody in UCB had a heck of a trip... 24941da177e4SLinus Torvalds * Problems: 24951da177e4SLinus Torvalds * a) we can get into loop creation. Check is done in is_subdir(). 24961da177e4SLinus Torvalds * b) race potential - two innocent renames can create a loop together. 24971da177e4SLinus Torvalds * That's where 4.4 screws up. Current fix: serialization on 2498a11f3a05SArjan van de Ven * sb->s_vfs_rename_mutex. We might be more accurate, but that's another 24991da177e4SLinus Torvalds * story. 25001da177e4SLinus Torvalds * c) we have to lock _three_ objects - parents and victim (if it exists). 25011b1dcc1bSJes Sorensen * And that - after we got ->i_mutex on parents (until then we don't know 25021da177e4SLinus Torvalds * whether the target exists). Solution: try to be smart with locking 25031da177e4SLinus Torvalds * order for inodes. We rely on the fact that tree topology may change 2504a11f3a05SArjan van de Ven * only under ->s_vfs_rename_mutex _and_ that parent of the object we 25051da177e4SLinus Torvalds * move will be locked. Thus we can rank directories by the tree 25061da177e4SLinus Torvalds * (ancestors first) and rank all non-directories after them. 25071da177e4SLinus Torvalds * That works since everybody except rename does "lock parent, lookup, 2508a11f3a05SArjan van de Ven * lock child" and rename is under ->s_vfs_rename_mutex. 25091da177e4SLinus Torvalds * HOWEVER, it relies on the assumption that any object with ->lookup() 25101da177e4SLinus Torvalds * has no more than 1 dentry. If "hybrid" objects will ever appear, 25111da177e4SLinus Torvalds * we'd better make sure that there's no link(2) for them. 25121da177e4SLinus Torvalds * d) some filesystems don't support opened-but-unlinked directories, 25131da177e4SLinus Torvalds * either because of layout or because they are not ready to deal with 25141da177e4SLinus Torvalds * all cases correctly. The latter will be fixed (taking this sort of 25151da177e4SLinus Torvalds * stuff into VFS), but the former is not going away. Solution: the same 25161da177e4SLinus Torvalds * trick as in rmdir(). 25171da177e4SLinus Torvalds * e) conversion from fhandle to dentry may come in the wrong moment - when 25181b1dcc1bSJes Sorensen * we are removing the target. Solution: we will have to grab ->i_mutex 25191da177e4SLinus Torvalds * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on 25201b1dcc1bSJes Sorensen * ->i_mutex on parents, which works but leads to some truely excessive 25211da177e4SLinus Torvalds * locking]. 25221da177e4SLinus Torvalds */ 252375c96f85SAdrian Bunk static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, 25241da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25251da177e4SLinus Torvalds { 25261da177e4SLinus Torvalds int error = 0; 25271da177e4SLinus Torvalds struct inode *target; 25281da177e4SLinus Torvalds 25291da177e4SLinus Torvalds /* 25301da177e4SLinus Torvalds * If we are going to change the parent - check write permissions, 25311da177e4SLinus Torvalds * we'll need to flip '..'. 25321da177e4SLinus Torvalds */ 25331da177e4SLinus Torvalds if (new_dir != old_dir) { 2534f419a2e3SAl Viro error = inode_permission(old_dentry->d_inode, MAY_WRITE); 25351da177e4SLinus Torvalds if (error) 25361da177e4SLinus Torvalds return error; 25371da177e4SLinus Torvalds } 25381da177e4SLinus Torvalds 25391da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25401da177e4SLinus Torvalds if (error) 25411da177e4SLinus Torvalds return error; 25421da177e4SLinus Torvalds 25431da177e4SLinus Torvalds target = new_dentry->d_inode; 25441da177e4SLinus Torvalds if (target) { 25451b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25461da177e4SLinus Torvalds dentry_unhash(new_dentry); 25471da177e4SLinus Torvalds } 25481da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25491da177e4SLinus Torvalds error = -EBUSY; 25501da177e4SLinus Torvalds else 25511da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25521da177e4SLinus Torvalds if (target) { 25531da177e4SLinus Torvalds if (!error) 25541da177e4SLinus Torvalds target->i_flags |= S_DEAD; 25551b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25561da177e4SLinus Torvalds if (d_unhashed(new_dentry)) 25571da177e4SLinus Torvalds d_rehash(new_dentry); 25581da177e4SLinus Torvalds dput(new_dentry); 25591da177e4SLinus Torvalds } 2560e31e14ecSStephen Smalley if (!error) 2561349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25621da177e4SLinus Torvalds d_move(old_dentry,new_dentry); 25631da177e4SLinus Torvalds return error; 25641da177e4SLinus Torvalds } 25651da177e4SLinus Torvalds 256675c96f85SAdrian Bunk static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, 25671da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25681da177e4SLinus Torvalds { 25691da177e4SLinus Torvalds struct inode *target; 25701da177e4SLinus Torvalds int error; 25711da177e4SLinus Torvalds 25721da177e4SLinus Torvalds error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); 25731da177e4SLinus Torvalds if (error) 25741da177e4SLinus Torvalds return error; 25751da177e4SLinus Torvalds 25761da177e4SLinus Torvalds dget(new_dentry); 25771da177e4SLinus Torvalds target = new_dentry->d_inode; 25781da177e4SLinus Torvalds if (target) 25791b1dcc1bSJes Sorensen mutex_lock(&target->i_mutex); 25801da177e4SLinus Torvalds if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) 25811da177e4SLinus Torvalds error = -EBUSY; 25821da177e4SLinus Torvalds else 25831da177e4SLinus Torvalds error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); 25841da177e4SLinus Torvalds if (!error) { 2585349457ccSMark Fasheh if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) 25861da177e4SLinus Torvalds d_move(old_dentry, new_dentry); 25871da177e4SLinus Torvalds } 25881da177e4SLinus Torvalds if (target) 25891b1dcc1bSJes Sorensen mutex_unlock(&target->i_mutex); 25901da177e4SLinus Torvalds dput(new_dentry); 25911da177e4SLinus Torvalds return error; 25921da177e4SLinus Torvalds } 25931da177e4SLinus Torvalds 25941da177e4SLinus Torvalds int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, 25951da177e4SLinus Torvalds struct inode *new_dir, struct dentry *new_dentry) 25961da177e4SLinus Torvalds { 25971da177e4SLinus Torvalds int error; 25981da177e4SLinus Torvalds int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); 25990eeca283SRobert Love const char *old_name; 26001da177e4SLinus Torvalds 26011da177e4SLinus Torvalds if (old_dentry->d_inode == new_dentry->d_inode) 26021da177e4SLinus Torvalds return 0; 26031da177e4SLinus Torvalds 26041da177e4SLinus Torvalds error = may_delete(old_dir, old_dentry, is_dir); 26051da177e4SLinus Torvalds if (error) 26061da177e4SLinus Torvalds return error; 26071da177e4SLinus Torvalds 26081da177e4SLinus Torvalds if (!new_dentry->d_inode) 2609a95164d9SMiklos Szeredi error = may_create(new_dir, new_dentry); 26101da177e4SLinus Torvalds else 26111da177e4SLinus Torvalds error = may_delete(new_dir, new_dentry, is_dir); 26121da177e4SLinus Torvalds if (error) 26131da177e4SLinus Torvalds return error; 26141da177e4SLinus Torvalds 26151da177e4SLinus Torvalds if (!old_dir->i_op || !old_dir->i_op->rename) 26161da177e4SLinus Torvalds return -EPERM; 26171da177e4SLinus Torvalds 26181da177e4SLinus Torvalds DQUOT_INIT(old_dir); 26191da177e4SLinus Torvalds DQUOT_INIT(new_dir); 26201da177e4SLinus Torvalds 26210eeca283SRobert Love old_name = fsnotify_oldname_init(old_dentry->d_name.name); 26220eeca283SRobert Love 26231da177e4SLinus Torvalds if (is_dir) 26241da177e4SLinus Torvalds error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); 26251da177e4SLinus Torvalds else 26261da177e4SLinus Torvalds error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); 26271da177e4SLinus Torvalds if (!error) { 26280eeca283SRobert Love const char *new_name = old_dentry->d_name.name; 262989204c40SJohn McCutchan fsnotify_move(old_dir, new_dir, old_name, new_name, is_dir, 26305a190ae6SAl Viro new_dentry->d_inode, old_dentry); 26311da177e4SLinus Torvalds } 26320eeca283SRobert Love fsnotify_oldname_free(old_name); 26330eeca283SRobert Love 26341da177e4SLinus Torvalds return error; 26351da177e4SLinus Torvalds } 26361da177e4SLinus Torvalds 26372ad94ae6SAl Viro asmlinkage long sys_renameat(int olddfd, const char __user *oldname, 26382ad94ae6SAl Viro int newdfd, const char __user *newname) 26391da177e4SLinus Torvalds { 26401da177e4SLinus Torvalds struct dentry *old_dir, *new_dir; 26411da177e4SLinus Torvalds struct dentry *old_dentry, *new_dentry; 26421da177e4SLinus Torvalds struct dentry *trap; 26431da177e4SLinus Torvalds struct nameidata oldnd, newnd; 26442ad94ae6SAl Viro char *from; 26452ad94ae6SAl Viro char *to; 26462ad94ae6SAl Viro int error; 26471da177e4SLinus Torvalds 26482ad94ae6SAl Viro error = user_path_parent(olddfd, oldname, &oldnd, &from); 26491da177e4SLinus Torvalds if (error) 26501da177e4SLinus Torvalds goto exit; 26511da177e4SLinus Torvalds 26522ad94ae6SAl Viro error = user_path_parent(newdfd, newname, &newnd, &to); 26531da177e4SLinus Torvalds if (error) 26541da177e4SLinus Torvalds goto exit1; 26551da177e4SLinus Torvalds 26561da177e4SLinus Torvalds error = -EXDEV; 26574ac91378SJan Blunck if (oldnd.path.mnt != newnd.path.mnt) 26581da177e4SLinus Torvalds goto exit2; 26591da177e4SLinus Torvalds 26604ac91378SJan Blunck old_dir = oldnd.path.dentry; 26611da177e4SLinus Torvalds error = -EBUSY; 26621da177e4SLinus Torvalds if (oldnd.last_type != LAST_NORM) 26631da177e4SLinus Torvalds goto exit2; 26641da177e4SLinus Torvalds 26654ac91378SJan Blunck new_dir = newnd.path.dentry; 26661da177e4SLinus Torvalds if (newnd.last_type != LAST_NORM) 26671da177e4SLinus Torvalds goto exit2; 26681da177e4SLinus Torvalds 26690612d9fbSOGAWA Hirofumi oldnd.flags &= ~LOOKUP_PARENT; 26700612d9fbSOGAWA Hirofumi newnd.flags &= ~LOOKUP_PARENT; 26714e9ed2f8SOGAWA Hirofumi newnd.flags |= LOOKUP_RENAME_TARGET; 26720612d9fbSOGAWA Hirofumi 26731da177e4SLinus Torvalds trap = lock_rename(new_dir, old_dir); 26741da177e4SLinus Torvalds 267549705b77SChristoph Hellwig old_dentry = lookup_hash(&oldnd); 26761da177e4SLinus Torvalds error = PTR_ERR(old_dentry); 26771da177e4SLinus Torvalds if (IS_ERR(old_dentry)) 26781da177e4SLinus Torvalds goto exit3; 26791da177e4SLinus Torvalds /* source must exist */ 26801da177e4SLinus Torvalds error = -ENOENT; 26811da177e4SLinus Torvalds if (!old_dentry->d_inode) 26821da177e4SLinus Torvalds goto exit4; 26831da177e4SLinus Torvalds /* unless the source is a directory trailing slashes give -ENOTDIR */ 26841da177e4SLinus Torvalds if (!S_ISDIR(old_dentry->d_inode->i_mode)) { 26851da177e4SLinus Torvalds error = -ENOTDIR; 26861da177e4SLinus Torvalds if (oldnd.last.name[oldnd.last.len]) 26871da177e4SLinus Torvalds goto exit4; 26881da177e4SLinus Torvalds if (newnd.last.name[newnd.last.len]) 26891da177e4SLinus Torvalds goto exit4; 26901da177e4SLinus Torvalds } 26911da177e4SLinus Torvalds /* source should not be ancestor of target */ 26921da177e4SLinus Torvalds error = -EINVAL; 26931da177e4SLinus Torvalds if (old_dentry == trap) 26941da177e4SLinus Torvalds goto exit4; 269549705b77SChristoph Hellwig new_dentry = lookup_hash(&newnd); 26961da177e4SLinus Torvalds error = PTR_ERR(new_dentry); 26971da177e4SLinus Torvalds if (IS_ERR(new_dentry)) 26981da177e4SLinus Torvalds goto exit4; 26991da177e4SLinus Torvalds /* target should not be an ancestor of source */ 27001da177e4SLinus Torvalds error = -ENOTEMPTY; 27011da177e4SLinus Torvalds if (new_dentry == trap) 27021da177e4SLinus Torvalds goto exit5; 27031da177e4SLinus Torvalds 27049079b1ebSDave Hansen error = mnt_want_write(oldnd.path.mnt); 27059079b1ebSDave Hansen if (error) 27069079b1ebSDave Hansen goto exit5; 2707be6d3e56SKentaro Takeda error = security_path_rename(&oldnd.path, old_dentry, 2708be6d3e56SKentaro Takeda &newnd.path, new_dentry); 2709be6d3e56SKentaro Takeda if (error) 2710be6d3e56SKentaro Takeda goto exit6; 27111da177e4SLinus Torvalds error = vfs_rename(old_dir->d_inode, old_dentry, 27121da177e4SLinus Torvalds new_dir->d_inode, new_dentry); 2713be6d3e56SKentaro Takeda exit6: 27149079b1ebSDave Hansen mnt_drop_write(oldnd.path.mnt); 27151da177e4SLinus Torvalds exit5: 27161da177e4SLinus Torvalds dput(new_dentry); 27171da177e4SLinus Torvalds exit4: 27181da177e4SLinus Torvalds dput(old_dentry); 27191da177e4SLinus Torvalds exit3: 27201da177e4SLinus Torvalds unlock_rename(new_dir, old_dir); 27211da177e4SLinus Torvalds exit2: 27221d957f9bSJan Blunck path_put(&newnd.path); 27232ad94ae6SAl Viro putname(to); 27241da177e4SLinus Torvalds exit1: 27251d957f9bSJan Blunck path_put(&oldnd.path); 27261da177e4SLinus Torvalds putname(from); 27272ad94ae6SAl Viro exit: 27281da177e4SLinus Torvalds return error; 27291da177e4SLinus Torvalds } 27301da177e4SLinus Torvalds 27315590ff0dSUlrich Drepper asmlinkage long sys_rename(const char __user *oldname, const char __user *newname) 27325590ff0dSUlrich Drepper { 27335590ff0dSUlrich Drepper return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); 27345590ff0dSUlrich Drepper } 27355590ff0dSUlrich Drepper 27361da177e4SLinus Torvalds int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) 27371da177e4SLinus Torvalds { 27381da177e4SLinus Torvalds int len; 27391da177e4SLinus Torvalds 27401da177e4SLinus Torvalds len = PTR_ERR(link); 27411da177e4SLinus Torvalds if (IS_ERR(link)) 27421da177e4SLinus Torvalds goto out; 27431da177e4SLinus Torvalds 27441da177e4SLinus Torvalds len = strlen(link); 27451da177e4SLinus Torvalds if (len > (unsigned) buflen) 27461da177e4SLinus Torvalds len = buflen; 27471da177e4SLinus Torvalds if (copy_to_user(buffer, link, len)) 27481da177e4SLinus Torvalds len = -EFAULT; 27491da177e4SLinus Torvalds out: 27501da177e4SLinus Torvalds return len; 27511da177e4SLinus Torvalds } 27521da177e4SLinus Torvalds 27531da177e4SLinus Torvalds /* 27541da177e4SLinus Torvalds * A helper for ->readlink(). This should be used *ONLY* for symlinks that 27551da177e4SLinus Torvalds * have ->follow_link() touching nd only in nd_set_link(). Using (or not 27561da177e4SLinus Torvalds * using) it for any given inode is up to filesystem. 27571da177e4SLinus Torvalds */ 27581da177e4SLinus Torvalds int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27591da177e4SLinus Torvalds { 27601da177e4SLinus Torvalds struct nameidata nd; 2761cc314eefSLinus Torvalds void *cookie; 2762694a1764SMarcin Slusarz int res; 2763cc314eefSLinus Torvalds 27641da177e4SLinus Torvalds nd.depth = 0; 2765cc314eefSLinus Torvalds cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); 2766694a1764SMarcin Slusarz if (IS_ERR(cookie)) 2767694a1764SMarcin Slusarz return PTR_ERR(cookie); 2768694a1764SMarcin Slusarz 2769694a1764SMarcin Slusarz res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); 27701da177e4SLinus Torvalds if (dentry->d_inode->i_op->put_link) 2771cc314eefSLinus Torvalds dentry->d_inode->i_op->put_link(dentry, &nd, cookie); 2772694a1764SMarcin Slusarz return res; 27731da177e4SLinus Torvalds } 27741da177e4SLinus Torvalds 27751da177e4SLinus Torvalds int vfs_follow_link(struct nameidata *nd, const char *link) 27761da177e4SLinus Torvalds { 27771da177e4SLinus Torvalds return __vfs_follow_link(nd, link); 27781da177e4SLinus Torvalds } 27791da177e4SLinus Torvalds 27801da177e4SLinus Torvalds /* get the link contents into pagecache */ 27811da177e4SLinus Torvalds static char *page_getlink(struct dentry * dentry, struct page **ppage) 27821da177e4SLinus Torvalds { 2783ebd09abbSDuane Griffin char *kaddr; 27841da177e4SLinus Torvalds struct page *page; 27851da177e4SLinus Torvalds struct address_space *mapping = dentry->d_inode->i_mapping; 2786090d2b18SPekka Enberg page = read_mapping_page(mapping, 0, NULL); 27871da177e4SLinus Torvalds if (IS_ERR(page)) 27886fe6900eSNick Piggin return (char*)page; 27891da177e4SLinus Torvalds *ppage = page; 2790ebd09abbSDuane Griffin kaddr = kmap(page); 2791ebd09abbSDuane Griffin nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); 2792ebd09abbSDuane Griffin return kaddr; 27931da177e4SLinus Torvalds } 27941da177e4SLinus Torvalds 27951da177e4SLinus Torvalds int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) 27961da177e4SLinus Torvalds { 27971da177e4SLinus Torvalds struct page *page = NULL; 27981da177e4SLinus Torvalds char *s = page_getlink(dentry, &page); 27991da177e4SLinus Torvalds int res = vfs_readlink(dentry,buffer,buflen,s); 28001da177e4SLinus Torvalds if (page) { 28011da177e4SLinus Torvalds kunmap(page); 28021da177e4SLinus Torvalds page_cache_release(page); 28031da177e4SLinus Torvalds } 28041da177e4SLinus Torvalds return res; 28051da177e4SLinus Torvalds } 28061da177e4SLinus Torvalds 2807cc314eefSLinus Torvalds void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) 28081da177e4SLinus Torvalds { 2809cc314eefSLinus Torvalds struct page *page = NULL; 28101da177e4SLinus Torvalds nd_set_link(nd, page_getlink(dentry, &page)); 2811cc314eefSLinus Torvalds return page; 28121da177e4SLinus Torvalds } 28131da177e4SLinus Torvalds 2814cc314eefSLinus Torvalds void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) 28151da177e4SLinus Torvalds { 2816cc314eefSLinus Torvalds struct page *page = cookie; 2817cc314eefSLinus Torvalds 2818cc314eefSLinus Torvalds if (page) { 28191da177e4SLinus Torvalds kunmap(page); 28201da177e4SLinus Torvalds page_cache_release(page); 28211da177e4SLinus Torvalds } 28221da177e4SLinus Torvalds } 28231da177e4SLinus Torvalds 28240adb25d2SKirill Korotaev int __page_symlink(struct inode *inode, const char *symname, int len, 28250adb25d2SKirill Korotaev gfp_t gfp_mask) 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; 28321da177e4SLinus Torvalds 28337e53cac4SNeilBrown retry: 2834afddba49SNick Piggin err = pagecache_write_begin(NULL, mapping, 0, len-1, 2835afddba49SNick Piggin AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); 28361da177e4SLinus Torvalds if (err) 2837afddba49SNick Piggin goto fail; 2838afddba49SNick Piggin 28391da177e4SLinus Torvalds kaddr = kmap_atomic(page, KM_USER0); 28401da177e4SLinus Torvalds memcpy(kaddr, symname, len-1); 28411da177e4SLinus Torvalds kunmap_atomic(kaddr, KM_USER0); 2842afddba49SNick Piggin 2843afddba49SNick Piggin err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, 2844afddba49SNick Piggin page, fsdata); 28451da177e4SLinus Torvalds if (err < 0) 28461da177e4SLinus Torvalds goto fail; 2847afddba49SNick Piggin if (err < len-1) 2848afddba49SNick Piggin goto retry; 2849afddba49SNick Piggin 28501da177e4SLinus Torvalds mark_inode_dirty(inode); 28511da177e4SLinus Torvalds return 0; 28521da177e4SLinus Torvalds fail: 28531da177e4SLinus Torvalds return err; 28541da177e4SLinus Torvalds } 28551da177e4SLinus Torvalds 28560adb25d2SKirill Korotaev int page_symlink(struct inode *inode, const char *symname, int len) 28570adb25d2SKirill Korotaev { 28580adb25d2SKirill Korotaev return __page_symlink(inode, symname, len, 28590adb25d2SKirill Korotaev mapping_gfp_mask(inode->i_mapping)); 28600adb25d2SKirill Korotaev } 28610adb25d2SKirill Korotaev 286292e1d5beSArjan van de Ven const struct inode_operations page_symlink_inode_operations = { 28631da177e4SLinus Torvalds .readlink = generic_readlink, 28641da177e4SLinus Torvalds .follow_link = page_follow_link_light, 28651da177e4SLinus Torvalds .put_link = page_put_link, 28661da177e4SLinus Torvalds }; 28671da177e4SLinus Torvalds 28682d8f3038SAl Viro EXPORT_SYMBOL(user_path_at); 28691da177e4SLinus Torvalds EXPORT_SYMBOL(follow_down); 28701da177e4SLinus Torvalds EXPORT_SYMBOL(follow_up); 28711da177e4SLinus Torvalds EXPORT_SYMBOL(get_write_access); /* binfmt_aout */ 28721da177e4SLinus Torvalds EXPORT_SYMBOL(getname); 28731da177e4SLinus Torvalds EXPORT_SYMBOL(lock_rename); 28741da177e4SLinus Torvalds EXPORT_SYMBOL(lookup_one_len); 28751da177e4SLinus Torvalds EXPORT_SYMBOL(page_follow_link_light); 28761da177e4SLinus Torvalds EXPORT_SYMBOL(page_put_link); 28771da177e4SLinus Torvalds EXPORT_SYMBOL(page_readlink); 28780adb25d2SKirill Korotaev EXPORT_SYMBOL(__page_symlink); 28791da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink); 28801da177e4SLinus Torvalds EXPORT_SYMBOL(page_symlink_inode_operations); 28811da177e4SLinus Torvalds EXPORT_SYMBOL(path_lookup); 2882d1811465SAl Viro EXPORT_SYMBOL(kern_path); 288316f18200SJosef 'Jeff' Sipek EXPORT_SYMBOL(vfs_path_lookup); 2884f419a2e3SAl Viro EXPORT_SYMBOL(inode_permission); 2885e4543eddSChristoph Hellwig EXPORT_SYMBOL(vfs_permission); 28868c744fb8SChristoph Hellwig EXPORT_SYMBOL(file_permission); 28871da177e4SLinus Torvalds EXPORT_SYMBOL(unlock_rename); 28881da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_create); 28891da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_follow_link); 28901da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_link); 28911da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mkdir); 28921da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_mknod); 28931da177e4SLinus Torvalds EXPORT_SYMBOL(generic_permission); 28941da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_readlink); 28951da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rename); 28961da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_rmdir); 28971da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_symlink); 28981da177e4SLinus Torvalds EXPORT_SYMBOL(vfs_unlink); 28991da177e4SLinus Torvalds EXPORT_SYMBOL(dentry_unhash); 29001da177e4SLinus Torvalds EXPORT_SYMBOL(generic_readlink); 2901