From 3f9f0aa687d45cbc8e7bb3cfd3aab555dcc8872e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 28 Apr 2012 14:38:32 -0700 Subject: VFS: clean up and simplify getname_flags() This removes a number of silly games around strncpy_from_user() in do_getname(), and removes that helper function entirely. We instead make getname_flags() just use strncpy_from_user() properly directly. Removing the wrapper function simplifies things noticeably, mostly because we no longer play the unnecessary games with segments (x86 strncpy_from_user() no longer needs the hack), but also because the empty path handling is just much more obvious. The return value of "strncpy_to_user()" is much more obvious than checking an odd error return case from do_getname(). [ non-x86 architectures were notified of this change several weeks ago, since it is possible that they have copied the old broken x86 strncpy_from_user. But nobody reacted, so .. See http://www.spinics.net/lists/linux-arch/msg17313.html for details ] Cc: linux-arch@vger.kernel.org Signed-off-by: Linus Torvalds --- fs/namei.c | 58 ++++++++++++++++++++++++---------------------------------- 1 file changed, 24 insertions(+), 34 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 0062dd17eb55..494b1caa25f8 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) -- cgit v1.2.3