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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 08:46:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-21 08:46:08 -0700
commit7e5cb5e151c5474b4a468f437f5038ba9f67ef4d (patch)
tree899f42e88f926fb4501402cf4ee4aa0903421ef5 /fs/namei.c
parent8c12fec90c54cfabdd57b2726a1defbc07c19a55 (diff)
parente994defb7b6813ba6fa7a2a36e86d2455ad1dc35 (diff)
Merge branch 'vfs-cleanups' (random vfs cleanups)
This teaches vfs_fstat() to use the appropriate f[get|put]_light functions, allowing it to avoid some unnecessary locking for the common case. More noticeably, it also cleans up and simplifies the "getname_flags()" function, which now relies on the architecture strncpy_from_user() doing all the user access checks properly, instead of hacking around the fact that on x86 it didn't use to do it right (see commit 92ae03f2ef99: "x86: merge 32/64-bit versions of 'strncpy_from_user()' and speed it up"). * vfs-cleanups: VFS: make vfs_fstat() use f[get|put]_light() VFS: clean up and simplify getname_flags() x86: make word-at-a-time strncpy_from_user clear bytes at the end
Diffstat (limited to 'fs/namei.c')
-rw-r--r--fs/namei.c58
1 files changed, 24 insertions, 34 deletions
diff --git a/fs/namei.c b/fs/namei.c
index c42791914f82..709fb2c17b5f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -116,47 +116,37 @@
* POSIX.1 2.4: an empty pathname is invalid (ENOENT).
* PATH_MAX includes the nul terminator --RR.
*/
-static int do_getname(const char __user *filename, char *page)
-{
- int retval;
- unsigned long len = PATH_MAX;
-
- if (!segment_eq(get_fs(), KERNEL_DS)) {
- if ((unsigned long) filename >= TASK_SIZE)
- return -EFAULT;
- if (TASK_SIZE - (unsigned long) filename < PATH_MAX)
- len = TASK_SIZE - (unsigned long) filename;
- }
-
- retval = strncpy_from_user(page, filename, len);
- if (retval > 0) {
- if (retval < len)
- return 0;
- return -ENAMETOOLONG;
- } else if (!retval)
- retval = -ENOENT;
- return retval;
-}
-
static char *getname_flags(const char __user *filename, int flags, int *empty)
{
- char *result = __getname();
- int retval;
+ char *result = __getname(), *err;
+ int len;
- if (!result)
+ if (unlikely(!result))
return ERR_PTR(-ENOMEM);
- retval = do_getname(filename, result);
- if (retval < 0) {
- if (retval == -ENOENT && empty)
+ len = strncpy_from_user(result, filename, PATH_MAX);
+ err = ERR_PTR(len);
+ if (unlikely(len < 0))
+ goto error;
+
+ /* The empty path is special. */
+ if (unlikely(!len)) {
+ if (empty)
*empty = 1;
- if (retval != -ENOENT || !(flags & LOOKUP_EMPTY)) {
- __putname(result);
- return ERR_PTR(retval);
- }
+ err = ERR_PTR(-ENOENT);
+ if (!(flags & LOOKUP_EMPTY))
+ goto error;
}
- audit_getname(result);
- return result;
+
+ err = ERR_PTR(-ENAMETOOLONG);
+ if (likely(len < PATH_MAX)) {
+ audit_getname(result);
+ return result;
+ }
+
+error:
+ __putname(result);
+ return err;
}
char *getname(const char __user * filename)