diff options
| -rw-r--r-- | fs/dcache.c | 54 | ||||
| -rw-r--r-- | fs/proc/base.c | 2 | ||||
| -rw-r--r-- | include/linux/dcache.h | 1 | ||||
| -rw-r--r-- | include/linux/path.h | 5 |
4 files changed, 57 insertions, 5 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 7fccb00f498d..166d35d56868 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2019,6 +2019,11 @@ static int path_with_deleted(const struct path *path, struct path *root, return prepend_path(path, root, buf, buflen); } +static int prepend_unreachable(char **buffer, int *buflen) +{ + return prepend(buffer, buflen, "(unreachable)", 13); +} + /** * d_path - return the path of a dentry * @path: path to report @@ -2064,6 +2069,39 @@ char *d_path(const struct path *path, char *buf, int buflen) } EXPORT_SYMBOL(d_path); +/** + * d_path_with_unreachable - return the path of a dentry + * @path: path to report + * @buf: buffer to return value in + * @buflen: buffer length + * + * The difference from d_path() is that this prepends "(unreachable)" + * to paths which are unreachable from the current process' root. + */ +char *d_path_with_unreachable(const struct path *path, char *buf, int buflen) +{ + char *res = buf + buflen; + struct path root; + struct path tmp; + int error; + + if (path->dentry->d_op && path->dentry->d_op->d_dname) + return path->dentry->d_op->d_dname(path->dentry, buf, buflen); + + get_fs_root(current->fs, &root); + spin_lock(&dcache_lock); + tmp = root; + error = path_with_deleted(path, &tmp, &res, &buflen); + if (!error && !path_equal(&tmp, &root)) + error = prepend_unreachable(&res, &buflen); + spin_unlock(&dcache_lock); + path_put(&root); + if (error) + res = ERR_PTR(error); + + return res; +} + /* * Helper function for dentry_operations.d_dname() members */ @@ -2173,15 +2211,23 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) if (!d_unlinked(pwd.dentry)) { unsigned long len; struct path tmp = root; - char * cwd; + char *cwd = page + PAGE_SIZE; + int buflen = PAGE_SIZE; - cwd = __d_path(&pwd, &tmp, page, PAGE_SIZE); + prepend(&cwd, &buflen, "\0", 1); + error = prepend_path(&pwd, &tmp, &cwd, &buflen); spin_unlock(&dcache_lock); - error = PTR_ERR(cwd); - if (IS_ERR(cwd)) + if (error) goto out; + /* Unreachable from current root */ + if (!path_equal(&tmp, &root)) { + error = prepend_unreachable(&cwd, &buflen); + if (error) + goto out; + } + error = -ERANGE; len = PAGE_SIZE + page - cwd; if (len <= size) { diff --git a/fs/proc/base.c b/fs/proc/base.c index 4cf5abf77ddf..a1c43e7c8a7b 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1526,7 +1526,7 @@ static int do_proc_readlink(struct path *path, char __user *buffer, int buflen) if (!tmp) return -ENOMEM; - pathname = d_path(path, tmp, PAGE_SIZE); + pathname = d_path_with_unreachable(path, tmp, PAGE_SIZE); len = PTR_ERR(pathname); if (IS_ERR(pathname)) goto out; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index d23be0386e2d..6a4aea30aa09 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -315,6 +315,7 @@ extern char *dynamic_dname(struct dentry *, char *, int, const char *, ...); extern char *__d_path(const struct path *path, struct path *root, char *, int); extern char *d_path(const struct path *, char *, int); +extern char *d_path_with_unreachable(const struct path *, char *, int); extern char *__dentry_path(struct dentry *, char *, int); extern char *dentry_path(struct dentry *, char *, int); diff --git a/include/linux/path.h b/include/linux/path.h index 915e0c382a51..edc98dec6266 100644 --- a/include/linux/path.h +++ b/include/linux/path.h @@ -12,4 +12,9 @@ struct path { extern void path_get(struct path *); extern void path_put(struct path *); +static inline int path_equal(const struct path *path1, const struct path *path2) +{ + return path1->mnt == path2->mnt && path1->dentry == path2->dentry; +} + #endif /* _LINUX_PATH_H */ |