From: Eric Blake <ebb9@byu.net>
Date: Thu, 31 Dec 2009 19:28:35 +0000 (-0700)
Subject: utimens: avoid shadowing warning
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f32ad11f3c49f708a37d6d6f0327bc8444df2dcd;p=pspp

utimens: avoid shadowing warning

lutimens declared struct stat st in two scopes.  Worse, on Linux
kernels between 2.6.18 and 2.6.22 (when utimensat existed, but
rejected AT_SYMLINK_NOFOLLOW) or before 2.6.18 (if the glibc
headers have utimensat, but the kernel does not), it would
result in redundant [fl]stat calls.

* lib/utimens.c (fdutimens, lutimens): Consolidate separate stat
buffers into one, to avoid shadowing, as well as avoiding a
redundant stat.
Reported by Jim Meyering.

Signed-off-by: Eric Blake <ebb9@byu.net>
---

diff --git a/ChangeLog b/ChangeLog
index 8d890808ee..9fc2aef733 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2009-12-31  Eric Blake  <ebb9@byu.net>
 
+	utimens: avoid shadowing warning
+	* lib/utimens.c (fdutimens, lutimens): Consolidate separate stat
+	buffers into one, to avoid shadowing, as well as avoiding a
+	redundant stat.
+	Reported by Jim Meyering.
+
 	test-dup2: avoid compiler warning
 	* tests/test-dup2.c (is_inheritable): Only define if used.
 
diff --git a/lib/utimens.c b/lib/utimens.c
index cc0d1e8f20..b3a9a4a5fe 100644
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -169,6 +169,7 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
   struct timespec adjusted_timespec[2];
   struct timespec *ts = timespec ? adjusted_timespec : NULL;
   int adjustment_needed = 0;
+  struct stat st;
 
   if (ts)
     {
@@ -220,7 +221,6 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
     {
       int result;
 # if __linux__
-      struct stat st;
       /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
          systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
          but work if both times are either explicitly specified or
@@ -237,6 +237,8 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
             ts[0] = get_stat_atime (&st);
           else if (ts[1].tv_nsec == UTIME_OMIT)
             ts[1] = get_stat_mtime (&st);
+          /* Note that st is good, in case utimensat gives ENOSYS.  */
+          adjustment_needed++;
         }
 # endif /* __linux__ */
 # if HAVE_UTIMENSAT
@@ -287,8 +289,8 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
 
   if (adjustment_needed || (REPLACE_FUNC_STAT_FILE && fd < 0))
     {
-      struct stat st;
-      if (fd < 0 ? stat (file, &st) : fstat (fd, &st))
+      if (adjustment_needed != 3
+          && (fd < 0 ? stat (file, &st) : fstat (fd, &st)))
         return -1;
       if (ts && update_timespec (&st, &ts))
         return 0;
@@ -422,7 +424,6 @@ lutimens (char const *file, struct timespec const timespec[2])
     {
       int result;
 # if __linux__
-      struct stat st;
       /* As recently as Linux kernel 2.6.32 (Dec 2009), several file
          systems (xfs, ntfs-3g) have bugs with a single UTIME_OMIT,
          but work if both times are either explicitly specified or
@@ -439,6 +440,8 @@ lutimens (char const *file, struct timespec const timespec[2])
             ts[0] = get_stat_atime (&st);
           else if (ts[1].tv_nsec == UTIME_OMIT)
             ts[1] = get_stat_mtime (&st);
+          /* Note that st is good, in case utimensat gives ENOSYS.  */
+          adjustment_needed++;
         }
 # endif /* __linux__ */
       result = utimensat (AT_FDCWD, file, ts, AT_SYMLINK_NOFOLLOW);
@@ -469,7 +472,7 @@ lutimens (char const *file, struct timespec const timespec[2])
 
   if (adjustment_needed || REPLACE_FUNC_STAT_FILE)
     {
-      if (lstat (file, &st))
+      if (adjustment_needed != 3 && lstat (file, &st))
         return -1;
       if (ts && update_timespec (&st, &ts))
         return 0;