'trap' portability trapped me...

[gnulib.git] / lib / utimens.c

diff --git a/lib/utimens.c b/lib/utimens.c
index 0b2f3e4..8d8bef4 100644 (file)
--- a/lib/utimens.c
+++ b/lib/utimens.c
@@ -26,6 +26,7 @@
 
 #include <errno.h>
 #include <fcntl.h>
+#include <unistd.h>
 
 #if HAVE_UTIME_H
 # include <utime.h>
@@ -41,6 +42,16 @@ struct utimbuf
 };
 #endif
 
+/* Some systems don't have ENOSYS.  */
+#ifndef ENOSYS
+# ifdef ENOTSUP
+#  define ENOSYS ENOTSUP
+# else
+/* Some systems don't have ENOTSUP either.  */
+#  define ENOSYS EINVAL
+# endif
+#endif
+
 #if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 8) || __STRICT_ANSI__
 # define __attribute__(x)
 #endif
@@ -53,7 +64,11 @@ struct utimbuf
    TIMESPEC[0] and TIMESPEC[1], respectively.
    FD must be either negative -- in which case it is ignored --
    or a file descriptor that is open on FILE.
-   If TIMESPEC is null, set the time stamps to the current time.  */
+   If FD is nonnegative, then FILE can be NULL, which means
+   use just futimes (or equivalent) instead of utimes (or equivalent),
+   and fail if on an old system without futimes (or equivalent).
+   If TIMESPEC is null, set the time stamps to the current time.
+   Return 0 on success, -1 (setting errno) on failure.  */
 
 int
 futimens (int fd ATTRIBUTE_UNUSED,
@@ -78,42 +93,64 @@ futimens (int fd ATTRIBUTE_UNUSED,
 
 # if HAVE_FUTIMESAT
   return fd < 0 ? futimesat (AT_FDCWD, file, t) : futimesat (fd, NULL, t);
-# else
-#  if HAVE_FUTIMES
+# elif HAVE_FUTIMES
   if (0 <= fd)
     {
       if (futimes (fd, t) == 0)
        return 0;
 
-      /* On GNU/Linux without the futimes syscall and without /proc
-        mounted, glibc futimes fails with errno == ENOENT.  Fall back
-        on utimes if we get a weird error number like that.  */
-      switch (errno)
-       {
-       case EACCES:
-       case EIO:
-       case EPERM:
-       case EROFS:
-         return -1;
-       }
+      /* Don't worry about trying to speed things up by returning right
+        away here.  glibc futimes 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 futimes incorrectly fails with errno == EACCES.  If futimes
+        fails with errno == EIO, EPERM, or EROFS, it's probably safe to
+        fail right away, but these cases are rare enough that they're not
+        worth optimizing, and who knows what other messed-up systems are
+        out there?  So play it safe and fall back on the code below.  */
     }
-#  endif
-  return utimes (file, t);
 # endif
+#endif
 
-#else
+#if ! HAVE_FUTIMESAT
 
-  struct utimbuf utimbuf;
-  struct utimbuf const *t;
-  if (timespec)
+  if (!file)
     {
-      utimbuf.actime = timespec[0].tv_sec;
-      utimbuf.modtime = timespec[1].tv_sec;
-      t = &utimbuf;
+# if ! (HAVE_WORKING_UTIMES && HAVE_FUTIMES)
+      errno = ENOSYS;
+# endif
+
+      /* Prefer EBADF to ENOSYS if both error numbers apply.  */
+      if (errno == ENOSYS)
+       {
+         int fd2 = dup (fd);
+         int dup_errno = errno;
+         if (0 <= fd2)
+           close (fd2);
+         errno = (fd2 < 0 && dup_errno == EBADF ? EBADF : ENOSYS);
+       }
+
+      return -1;
     }
-  else
-    t = NULL;
-  return utime (file, t);
+
+# if HAVE_WORKING_UTIMES
+  return utimes (file, t);
+# else
+  {
+    struct utimbuf utimbuf;
+    struct utimbuf const *ut;
+    if (timespec)
+      {
+       utimbuf.actime = timespec[0].tv_sec;
+       utimbuf.modtime = timespec[1].tv_sec;
+       ut = &utimbuf;
+      }
+    else
+      ut = NULL;
+
+    return utime (file, ut);
+  }
+# endif
 
 #endif
 }