utimens: fix regression on Solaris

Revert commit 26c5fd742f.  Solaris lacks futimens and futimes, so
futimesat is the only way to change fd timestamps.  But since
FreeBSD futimesat can't change fd timestamps, we need a configure
check to avoid the crash there.

* m4/utimens.m4 (gl_UTIMENS): Check for BSD bug.
* lib/utimens.c (fdutimens): Revert 2009-11-08 change; Solaris 10
can only change fd timestamps via futimesat.  Instead, use an
additional witness macro to avoid BSD bug.
Reported by Jim Meyering.

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

diff --git a/ChangeLog b/ChangeLog
index 62b5423ac242b8f95a7c1ba0ae5de3b0979eaa4b..649834bf25fb1a1d18bc0e8b0df23b53afc43d01 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2009-11-18  Eric Blake  <ebb9@byu.net>
+
+       utimens: fix regression on Solaris
+       * m4/utimens.m4 (gl_UTIMENS): Check for BSD bug.
+       * lib/utimens.c (fdutimens): Revert 2009-11-08 change; Solaris 10
+       can only change fd timestamps via futimesat.  Instead, use an
+       additional witness macro to avoid BSD bug.
+       Reported by Jim Meyering.
+
 2009-11-17  Eric Blake  <ebb9@byu.net>
 
        usleep: use it to simplify tests

diff --git a/lib/utimens.c b/lib/utimens.c
index bd482d7d01a48f0113801a8dc89d8c6eefe43007..eb63487c439d1606af41ca6b22159ca12790d199 100644 (file)
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -280,9 +280,9 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
       }
     else
       {
-        /* If futimesat (above) or futimes fails here, don't try to speed
-           things up by returning right away.  glibc can incorrectly fail
-           with errno == ENOENT if /proc isn't mounted.  Also, Mandrake 10.0
+        /* If futimesat or futimes fails here, don't try to speed things
+           up by returning right away.  glibc can incorrectly fail with
+           errno == ENOENT if /proc isn't mounted.  Also, Mandrake 10.0
            in high security mode doesn't allow ordinary users to read
            /proc/self, so glibc incorrectly fails with errno == EACCES.
            If errno == EIO, EPERM, or EROFS, it's probably safe to fail
@@ -290,7 +290,10 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
            worth optimizing, and who knows what other messed-up systems
            are out there?  So play it safe and fall back on the code
            below.  */
-# if HAVE_FUTIMES
+# if HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG
+        if (futimesat (fd, NULL, t) == 0)
+          return 0;
+# elif HAVE_FUTIMES
         if (futimes (fd, t) == 0)
           return 0;
 # endif
@@ -299,7 +302,8 @@ fdutimens (char const *file, int fd, struct timespec const timespec[2])
 
     if (!file)
       {
-#if ! (HAVE_FUTIMESAT || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
+#if ! ((HAVE_FUTIMESAT && !FUTIMESAT_NULL_BUG)          \
+        || (HAVE_WORKING_UTIMES && HAVE_FUTIMES))
         errno = ENOSYS;
 #endif
         return -1;

diff --git a/m4/utimens.m4 b/m4/utimens.m4
index 381d087d280e86067684c69efaa7288bd63daba0..35ef9490a22fa66b819b04544f408b3f52b5a32c 100644 (file)
--- a/m4/utimens.m4
+++ b/m4/utimens.m4
@@ -4,7 +4,7 @@ dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
 
-dnl serial 3
+dnl serial 4
 
 AC_DEFUN([gl_UTIMENS],
 [
@@ -15,4 +15,28 @@ AC_DEFUN([gl_UTIMENS],
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_TIMESPEC])
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_UTIMBUF])
   AC_CHECK_FUNCS_ONCE([futimes futimesat futimens utimensat lutimes])
+
+  if test $ac_cv_func_futimens = no && test $ac_cv_func_futimesat = yes; then
+    dnl FreeBSD 8.0-rc2 mishandles futimesat(fd,NULL,time).  It is not
+    dnl standardized, but Solaris implemented it first and uses it as
+    dnl its only means to set fd time.
+    AC_CACHE_CHECK([whether futimesat handles NULL file],
+      [gl_cv_func_futimesat_works],
+      [touch conftest.file
+       AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <stddef.h>
+#include <sys/times.h>
+]], [[    int fd = open ("conftest.file", O_RDWR);
+          if (fd < 0) return 1;
+          if (futimesat (fd, NULL, NULL)) return 2;
+        ]])],
+        [gl_cv_func_futimesat_works=yes],
+        [gl_cv_func_futimesat_works=no],
+        [gl_cv_func_futimesat_works="guessing no"])
+      rm -f conftest.file])
+    if test "$gl_cv_func_futimesat_works" != yes; then
+      AC_DEFINE([FUTIMESAT_NULL_BUG], [1],
+        [Define to 1 if futimesat mishandles a NULL file name.])
+    fi
+  fi
 ])