X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=fs%2Fnamei.c;h=33fb5bd34a8111c73768cfac883fd4ea49ea07b8;hb=af8c85bb6d4e5352551277edd8448c4dfb2328ab;hp=b3f8a1966c9cafe0113370bb5843a9b91b96758f;hpb=a892acacd3a8546ac161526522f13b5174f2c471;p=linux-2.6 diff --git a/fs/namei.c b/fs/namei.c index b3f8a1966c..33fb5bd34a 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -28,6 +28,7 @@ #include #include #include +#include #include #include #include @@ -112,7 +113,7 @@ * POSIX.1 2.4: an empty pathname is invalid (ENOENT). * PATH_MAX includes the nul terminator --RR. */ -static inline int do_getname(const char __user *filename, char *page) +static int do_getname(const char __user *filename, char *page) { int retval; unsigned long len = PATH_MAX; @@ -256,6 +257,38 @@ int permission(struct inode *inode, int mask, struct nameidata *nd) return security_inode_permission(inode, mask, nd); } +/** + * vfs_permission - check for access rights to a given path + * @nd: lookup result that describes the path + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * + * Used to check for read/write/execute permissions on a path. + * We use "fsuid" for this, letting us set arbitrary permissions + * for filesystem access without changing the "normal" uids which + * are used for other things. + */ +int vfs_permission(struct nameidata *nd, int mask) +{ + return permission(nd->dentry->d_inode, mask, nd); +} + +/** + * file_permission - check for additional access rights to a given file + * @file: file to check access rights for + * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) + * + * Used to check for read/write/execute permissions on an already opened + * file. + * + * Note: + * Do not use this function in new code. All access checks should + * be done using vfs_permission(). + */ +int file_permission(struct file *file, int mask) +{ + return permission(file->f_dentry->d_inode, mask, NULL); +} + /* * get_write_access() gets write permission for a file. * put_write_access() releases this write permission. @@ -363,7 +396,7 @@ static struct dentry * cached_lookup(struct dentry * parent, struct qstr * name, * short-cut DAC fails, then call permission() to do more * complete permission check. */ -static inline int exec_permission_lite(struct inode *inode, +static int exec_permission_lite(struct inode *inode, struct nameidata *nd) { umode_t mode = inode->i_mode; @@ -406,7 +439,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s struct dentry * result; struct inode *dir = parent->d_inode; - down(&dir->i_sem); + mutex_lock(&dir->i_mutex); /* * First re-do the cached lookup just in case it was created * while we waited for the directory semaphore.. @@ -432,7 +465,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s else result = dentry; } - up(&dir->i_sem); + mutex_unlock(&dir->i_mutex); return result; } @@ -440,7 +473,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s * Uhhuh! Nasty case: the cache was re-populated while * we waited on the semaphore. Need to revalidate. */ - up(&dir->i_sem); + mutex_unlock(&dir->i_mutex); if (result->d_op && result->d_op->d_revalidate) { if (!result->d_op->d_revalidate(result, nd) && !d_invalidate(result)) { dput(result); @@ -453,7 +486,7 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s static int __emul_lookup_dentry(const char *, struct nameidata *); /* SMP-safe */ -static inline int +static __always_inline int walk_init_root(const char *name, struct nameidata *nd) { read_lock(¤t->fs->lock); @@ -471,7 +504,7 @@ walk_init_root(const char *name, struct nameidata *nd) return 1; } -static inline int __vfs_follow_link(struct nameidata *nd, const char *link) +static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) { int res = 0; char *name; @@ -511,7 +544,7 @@ struct path { struct dentry *dentry; }; -static inline int __do_follow_link(struct path *path, struct nameidata *nd) +static __always_inline int __do_follow_link(struct path *path, struct nameidata *nd) { int error; void *cookie; @@ -657,7 +690,7 @@ int follow_down(struct vfsmount **mnt, struct dentry **dentry) return 0; } -static inline void follow_dotdot(struct nameidata *nd) +static __always_inline void follow_dotdot(struct nameidata *nd) { while(1) { struct vfsmount *parent; @@ -765,9 +798,8 @@ static fastcall int __link_path_walk(const char * name, struct nameidata *nd) nd->flags |= LOOKUP_CONTINUE; err = exec_permission_lite(inode, nd); - if (err == -EAGAIN) { - err = permission(inode, MAY_EXEC, nd); - } + if (err == -EAGAIN) + err = vfs_permission(nd, MAY_EXEC); if (err) break; @@ -1109,8 +1141,9 @@ int path_lookup_open(const char *name, unsigned int lookup_flags, * @open_flags: open intent flags * @create_mode: create intent flags */ -int path_lookup_create(const char *name, unsigned int lookup_flags, - struct nameidata *nd, int open_flags, int create_mode) +static int path_lookup_create(const char *name, unsigned int lookup_flags, + struct nameidata *nd, int open_flags, + int create_mode) { return __path_lookup_intent_open(name, lookup_flags|LOOKUP_CREATE, nd, open_flags, create_mode); @@ -1173,9 +1206,9 @@ out: return dentry; } -struct dentry * lookup_hash(struct qstr *name, struct dentry * base) +struct dentry * lookup_hash(struct nameidata *nd) { - return __lookup_hash(name, base, NULL); + return __lookup_hash(&nd->last, nd->dentry, nd); } /* SMP-safe */ @@ -1199,7 +1232,7 @@ struct dentry * lookup_one_len(const char * name, struct dentry * base, int len) } this.hash = end_name_hash(hash); - return lookup_hash(&this, base); + return __lookup_hash(&this, base, NULL); access: return ERR_PTR(-EACCES); } @@ -1261,7 +1294,7 @@ static inline int check_sticky(struct inode *dir, struct inode *inode) * 10. We don't allow removal of NFS sillyrenamed files; it's handled by * nfs_async_unlink(). */ -static inline int may_delete(struct inode *dir,struct dentry *victim,int isdir) +static int may_delete(struct inode *dir,struct dentry *victim,int isdir) { int error; @@ -1334,7 +1367,7 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) struct dentry *p; if (p1 == p2) { - down(&p1->d_inode->i_sem); + mutex_lock(&p1->d_inode->i_mutex); return NULL; } @@ -1342,30 +1375,30 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) for (p = p1; p->d_parent != p; p = p->d_parent) { if (p->d_parent == p2) { - down(&p2->d_inode->i_sem); - down(&p1->d_inode->i_sem); + mutex_lock(&p2->d_inode->i_mutex); + mutex_lock(&p1->d_inode->i_mutex); return p; } } for (p = p2; p->d_parent != p; p = p->d_parent) { if (p->d_parent == p1) { - down(&p1->d_inode->i_sem); - down(&p2->d_inode->i_sem); + mutex_lock(&p1->d_inode->i_mutex); + mutex_lock(&p2->d_inode->i_mutex); return p; } } - down(&p1->d_inode->i_sem); - down(&p2->d_inode->i_sem); + mutex_lock(&p1->d_inode->i_mutex); + mutex_lock(&p2->d_inode->i_mutex); return NULL; } void unlock_rename(struct dentry *p1, struct dentry *p2) { - up(&p1->d_inode->i_sem); + mutex_unlock(&p1->d_inode->i_mutex); if (p1 != p2) { - up(&p2->d_inode->i_sem); + mutex_unlock(&p2->d_inode->i_mutex); up(&p1->d_inode->i_sb->s_vfs_rename_sem); } } @@ -1407,7 +1440,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) if (S_ISDIR(inode->i_mode) && (flag & FMODE_WRITE)) return -EISDIR; - error = permission(inode, acc_mode, nd); + error = vfs_permission(nd, acc_mode); if (error) return error; @@ -1459,7 +1492,7 @@ int may_open(struct nameidata *nd, int acc_mode, int flag) if (!error) { DQUOT_INIT(inode); - error = do_truncate(dentry, 0, NULL); + error = do_truncate(dentry, 0, ATTR_MTIME|ATTR_CTIME, NULL); } put_write_access(inode); if (error) @@ -1531,14 +1564,14 @@ int open_namei(const char * pathname, int flag, int mode, struct nameidata *nd) dir = nd->dentry; nd->flags &= ~LOOKUP_PARENT; - down(&dir->d_inode->i_sem); - path.dentry = __lookup_hash(&nd->last, nd->dentry, nd); + mutex_lock(&dir->d_inode->i_mutex); + path.dentry = lookup_hash(nd); path.mnt = nd->mnt; do_last: error = PTR_ERR(path.dentry); if (IS_ERR(path.dentry)) { - up(&dir->d_inode->i_sem); + mutex_unlock(&dir->d_inode->i_mutex); goto exit; } @@ -1547,7 +1580,7 @@ do_last: if (!IS_POSIXACL(dir->d_inode)) mode &= ~current->fs->umask; error = vfs_create(dir->d_inode, path.dentry, mode, nd); - up(&dir->d_inode->i_sem); + mutex_unlock(&dir->d_inode->i_mutex); dput(nd->dentry); nd->dentry = path.dentry; if (error) @@ -1561,7 +1594,7 @@ do_last: /* * It already exists. */ - up(&dir->d_inode->i_sem); + mutex_unlock(&dir->d_inode->i_mutex); error = -EEXIST; if (flag & O_EXCL) @@ -1633,8 +1666,8 @@ do_link: goto exit; } dir = nd->dentry; - down(&dir->d_inode->i_sem); - path.dentry = __lookup_hash(&nd->last, nd->dentry, nd); + mutex_lock(&dir->d_inode->i_mutex); + path.dentry = lookup_hash(nd); path.mnt = nd->mnt; __putname(nd->last.name); goto do_last; @@ -1648,13 +1681,13 @@ do_link: * Simple function to lookup and return a dentry and create it * if it doesn't exist. Is SMP-safe. * - * Returns with nd->dentry->d_inode->i_sem locked. + * Returns with nd->dentry->d_inode->i_mutex locked. */ struct dentry *lookup_create(struct nameidata *nd, int is_dir) { struct dentry *dentry = ERR_PTR(-EEXIST); - down(&nd->dentry->d_inode->i_sem); + mutex_lock(&nd->dentry->d_inode->i_mutex); /* * Yucky last component or no last component at all? * (foo/., foo/.., /////) @@ -1666,7 +1699,7 @@ struct dentry *lookup_create(struct nameidata *nd, int is_dir) /* * Do the final lookup. */ - dentry = lookup_hash(&nd->last, nd->dentry); + dentry = lookup_hash(nd); if (IS_ERR(dentry)) goto fail; @@ -1752,7 +1785,7 @@ asmlinkage long sys_mknod(const char __user * filename, int mode, unsigned dev) } dput(dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); path_release(&nd); out: putname(tmp); @@ -1804,7 +1837,7 @@ asmlinkage long sys_mkdir(const char __user * pathname, int mode) error = vfs_mkdir(nd.dentry->d_inode, dentry, mode); dput(dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); path_release(&nd); out: putname(tmp); @@ -1853,7 +1886,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) DQUOT_INIT(dir); - down(&dentry->d_inode->i_sem); + mutex_lock(&dentry->d_inode->i_mutex); dentry_unhash(dentry); if (d_mountpoint(dentry)) error = -EBUSY; @@ -1865,7 +1898,7 @@ int vfs_rmdir(struct inode *dir, struct dentry *dentry) dentry->d_inode->i_flags |= S_DEAD; } } - up(&dentry->d_inode->i_sem); + mutex_unlock(&dentry->d_inode->i_mutex); if (!error) { d_delete(dentry); } @@ -1900,14 +1933,14 @@ asmlinkage long sys_rmdir(const char __user * pathname) error = -EBUSY; goto exit1; } - down(&nd.dentry->d_inode->i_sem); - dentry = lookup_hash(&nd.last, nd.dentry); + mutex_lock(&nd.dentry->d_inode->i_mutex); + dentry = lookup_hash(&nd); error = PTR_ERR(dentry); if (!IS_ERR(dentry)) { error = vfs_rmdir(nd.dentry->d_inode, dentry); dput(dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); exit1: path_release(&nd); exit: @@ -1927,7 +1960,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) DQUOT_INIT(dir); - down(&dentry->d_inode->i_sem); + mutex_lock(&dentry->d_inode->i_mutex); if (d_mountpoint(dentry)) error = -EBUSY; else { @@ -1935,7 +1968,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) if (!error) error = dir->i_op->unlink(dir, dentry); } - up(&dentry->d_inode->i_sem); + mutex_unlock(&dentry->d_inode->i_mutex); /* We don't d_delete() NFS sillyrenamed files--they still exist. */ if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { @@ -1947,7 +1980,7 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry) /* * Make sure that the actual truncation of the file will occur outside its - * directory's i_sem. Truncate can take a long time if there is a lot of + * directory's i_mutex. Truncate can take a long time if there is a lot of * writeout happening, and we don't want to prevent access to the directory * while waiting on the I/O. */ @@ -1969,8 +2002,8 @@ asmlinkage long sys_unlink(const char __user * pathname) error = -EISDIR; if (nd.last_type != LAST_NORM) goto exit1; - down(&nd.dentry->d_inode->i_sem); - dentry = lookup_hash(&nd.last, nd.dentry); + mutex_lock(&nd.dentry->d_inode->i_mutex); + dentry = lookup_hash(&nd); error = PTR_ERR(dentry); if (!IS_ERR(dentry)) { /* Why not before? Because we want correct error value */ @@ -1983,7 +2016,7 @@ asmlinkage long sys_unlink(const char __user * pathname) exit2: dput(dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); if (inode) iput(inode); /* truncate the inode here */ exit1: @@ -2043,7 +2076,7 @@ asmlinkage long sys_symlink(const char __user * oldname, const char __user * new error = vfs_symlink(nd.dentry->d_inode, dentry, from, S_IALLUGO); dput(dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); path_release(&nd); out: putname(to); @@ -2081,10 +2114,10 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de if (error) return error; - down(&old_dentry->d_inode->i_sem); + mutex_lock(&old_dentry->d_inode->i_mutex); DQUOT_INIT(dir); error = dir->i_op->link(old_dentry, dir, new_dentry); - up(&old_dentry->d_inode->i_sem); + mutex_unlock(&old_dentry->d_inode->i_mutex); if (!error) fsnotify_create(dir, new_dentry->d_name.name); return error; @@ -2125,7 +2158,7 @@ asmlinkage long sys_link(const char __user * oldname, const char __user * newnam error = vfs_link(old_nd.dentry, nd.dentry->d_inode, new_dentry); dput(new_dentry); } - up(&nd.dentry->d_inode->i_sem); + mutex_unlock(&nd.dentry->d_inode->i_mutex); out_release: path_release(&nd); out: @@ -2146,7 +2179,7 @@ exit: * sb->s_vfs_rename_sem. We might be more accurate, but that's another * story. * c) we have to lock _three_ objects - parents and victim (if it exists). - * And that - after we got ->i_sem on parents (until then we don't know + * And that - after we got ->i_mutex on parents (until then we don't know * whether the target exists). Solution: try to be smart with locking * order for inodes. We rely on the fact that tree topology may change * only under ->s_vfs_rename_sem _and_ that parent of the object we @@ -2163,9 +2196,9 @@ exit: * stuff into VFS), but the former is not going away. Solution: the same * trick as in rmdir(). * e) conversion from fhandle to dentry may come in the wrong moment - when - * we are removing the target. Solution: we will have to grab ->i_sem + * we are removing the target. Solution: we will have to grab ->i_mutex * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on - * ->i_sem on parents, which works but leads to some truely excessive + * ->i_mutex on parents, which works but leads to some truely excessive * locking]. */ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, @@ -2190,7 +2223,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, target = new_dentry->d_inode; if (target) { - down(&target->i_sem); + mutex_lock(&target->i_mutex); dentry_unhash(new_dentry); } if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) @@ -2200,7 +2233,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, if (target) { if (!error) target->i_flags |= S_DEAD; - up(&target->i_sem); + mutex_unlock(&target->i_mutex); if (d_unhashed(new_dentry)) d_rehash(new_dentry); dput(new_dentry); @@ -2223,7 +2256,7 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, dget(new_dentry); target = new_dentry->d_inode; if (target) - down(&target->i_sem); + mutex_lock(&target->i_mutex); if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) error = -EBUSY; else @@ -2234,7 +2267,7 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, d_move(old_dentry, new_dentry); } if (target) - up(&target->i_sem); + mutex_unlock(&target->i_mutex); dput(new_dentry); return error; } @@ -2282,7 +2315,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, return error; } -static inline int do_rename(const char * oldname, const char * newname) +static int do_rename(const char * oldname, const char * newname) { int error = 0; struct dentry * old_dir, * new_dir; @@ -2313,7 +2346,7 @@ static inline int do_rename(const char * oldname, const char * newname) trap = lock_rename(new_dir, old_dir); - old_dentry = lookup_hash(&oldnd.last, old_dir); + old_dentry = lookup_hash(&oldnd); error = PTR_ERR(old_dentry); if (IS_ERR(old_dentry)) goto exit3; @@ -2333,7 +2366,7 @@ static inline int do_rename(const char * oldname, const char * newname) error = -EINVAL; if (old_dentry == trap) goto exit4; - new_dentry = lookup_hash(&newnd.last, new_dir); + new_dentry = lookup_hash(&newnd); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) goto exit4; @@ -2536,6 +2569,8 @@ EXPORT_SYMBOL(path_lookup); EXPORT_SYMBOL(path_release); EXPORT_SYMBOL(path_walk); EXPORT_SYMBOL(permission); +EXPORT_SYMBOL(vfs_permission); +EXPORT_SYMBOL(file_permission); EXPORT_SYMBOL(unlock_rename); EXPORT_SYMBOL(vfs_create); EXPORT_SYMBOL(vfs_follow_link);