diff options
| -rw-r--r-- | fs/dcache.c | 150 |
1 files changed, 80 insertions, 70 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index d68631f18df1..b5f613932912 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -1739,45 +1739,41 @@ shouldnt_be_hashed: * @rootmnt: vfsmnt to which the root dentry belongs * @buffer: buffer to return value in * @buflen: buffer length + * @fail_deleted: what to return for deleted files * - * Convert a dentry into an ASCII path name. If the entry has been deleted - * the string " (deleted)" is appended. Note that this is ambiguous. + * Convert a dentry into an ASCII path name. If the entry has been deleted, + * then if @fail_deleted is true, ERR_PTR(-ENOENT) is returned. Otherwise, + * the the string " (deleted)" is appended. Note that this is ambiguous. * - * Returns the buffer or an error code if the path was too long. - * - * "buflen" should be positive. Caller holds the dcache_lock. + * Returns the buffer or an error code. */ -static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt, - struct dentry *root, struct vfsmount *rootmnt, - char *buffer, int buflen) +static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt, + struct dentry *root, struct vfsmount *rootmnt, + char *buffer, int buflen, int fail_deleted) { - char * end = buffer+buflen; - char * retval; - int namelen; + int namelen, is_slash; + + if (buflen < 2) + return ERR_PTR(-ENAMETOOLONG); + buffer += --buflen; + *buffer = '\0'; - *--end = '\0'; - buflen--; + spin_lock(&dcache_lock); if (!IS_ROOT(dentry) && d_unhashed(dentry)) { - buflen -= 10; - end -= 10; - if (buflen < 0) + if (fail_deleted) { + buffer = ERR_PTR(-ENOENT); + goto out; + } + if (buflen < 10) goto Elong; - memcpy(end, " (deleted)", 10); + buflen -= 10; + buffer -= 10; + memcpy(buffer, " (deleted)", 10); } - - if (buflen < 1) - goto Elong; - /* Get '/' right */ - retval = end-1; - *retval = '/'; - - for (;;) { + while (dentry != root || vfsmnt != rootmnt) { struct dentry * parent; - if (dentry == root && vfsmnt == rootmnt) - break; if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) { - /* Global root? */ spin_lock(&vfsmount_lock); if (vfsmnt->mnt_parent == vfsmnt) { spin_unlock(&vfsmount_lock); @@ -1791,33 +1787,60 @@ static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt, parent = dentry->d_parent; prefetch(parent); namelen = dentry->d_name.len; - buflen -= namelen + 1; - if (buflen < 0) + if (buflen <= namelen) goto Elong; - end -= namelen; - memcpy(end, dentry->d_name.name, namelen); - *--end = '/'; - retval = end; + buflen -= namelen + 1; + buffer -= namelen; + memcpy(buffer, dentry->d_name.name, namelen); + *--buffer = '/'; dentry = parent; } + /* Get '/' right */ + if (*buffer != '/') + *--buffer = '/'; - return retval; +out: + spin_unlock(&dcache_lock); + return buffer; global_root: + /* + * We went past the (vfsmount, dentry) we were looking for and have + * either hit a root dentry, a lazily unmounted dentry, an + * unconnected dentry, or the file is on a pseudo filesystem. + */ namelen = dentry->d_name.len; - buflen -= namelen; - if (buflen < 0) + is_slash = (namelen == 1 && *dentry->d_name.name == '/'); + if (is_slash || (dentry->d_sb->s_flags & MS_NOUSER)) { + /* + * Make sure we won't return a pathname starting with '/'. + * + * Historically, we also glue together the root dentry and + * remaining name for pseudo filesystems like pipefs, which + * have the MS_NOUSER flag set. This results in pathnames + * like "pipe:[439336]". + */ + if (*buffer == '/') { + buffer++; + buflen++; + } + if (is_slash) + goto out; + } + if (buflen < namelen) goto Elong; - retval -= namelen-1; /* hit the slash */ - memcpy(retval, dentry->d_name.name, namelen); - return retval; + buffer -= namelen; + memcpy(buffer, dentry->d_name.name, namelen); + goto out; + Elong: - return ERR_PTR(-ENAMETOOLONG); + buffer = ERR_PTR(-ENAMETOOLONG); + goto out; } /* write full pathname into buffer and return start of pathname */ -char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, - char *buf, int buflen) +char *d_path(struct dentry *dentry, struct vfsmount *vfsmnt, char *buf, + int buflen) { char *res; struct vfsmount *rootmnt; @@ -1827,9 +1850,7 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, rootmnt = mntget(current->fs->rootmnt); root = dget(current->fs->root); read_unlock(¤t->fs->lock); - spin_lock(&dcache_lock); - res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen); - spin_unlock(&dcache_lock); + res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen, 0); dput(root); mntput(rootmnt); return res; @@ -1855,10 +1876,10 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt, */ asmlinkage long sys_getcwd(char __user *buf, unsigned long size) { - int error; + int error, len; struct vfsmount *pwdmnt, *rootmnt; struct dentry *pwd, *root; - char *page = (char *) __get_free_page(GFP_USER); + char *page = (char *) __get_free_page(GFP_USER), *cwd; if (!page) return -ENOMEM; @@ -1870,29 +1891,18 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size) root = dget(current->fs->root); read_unlock(¤t->fs->lock); - error = -ENOENT; - /* Has the current directory has been unlinked? */ - spin_lock(&dcache_lock); - if (pwd->d_parent == pwd || !d_unhashed(pwd)) { - unsigned long len; - char * cwd; - - cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE); - spin_unlock(&dcache_lock); - - error = PTR_ERR(cwd); - if (IS_ERR(cwd)) - goto out; + cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE, 1); + error = PTR_ERR(cwd); + if (IS_ERR(cwd)) + goto out; - error = -ERANGE; - len = PAGE_SIZE + page - cwd; - if (len <= size) { - error = len; - if (copy_to_user(buf, cwd, len)) - error = -EFAULT; - } - } else - spin_unlock(&dcache_lock); + error = -ERANGE; + len = PAGE_SIZE + page - cwd; + if (len <= size) { + error = len; + if (copy_to_user(buf, cwd, len)) + error = -EFAULT; + } out: dput(pwd); |