sysdeps/unix/sysv/linux/futimes.c

   1 /* futimes -- change access and modification times of open file.  Linux version.
   2    Copyright (C) 2002,2003,2005,2006 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <errno.h>
  21 #include <sysdep.h>
  22 #include <string.h>
  23 #include <utime.h>
  24 #include <sys/time.h>
  25 #include <stdio-common/_itoa.h>
  26 #include <fcntl.h>
  27
  28 #include <kernel-features.h>
  29
  30 /* Change the access time of FILE to TVP[0] and
  31    the modification time of FILE to TVP[1], but do not follow symlinks.
  32
  33    The Linux kernel has no futimes() syscall so we use the /proc
  34    filesystem.  */
  35 int
  36 __futimes (int fd, const struct timeval tvp[2])
  37 {
  38   static const char selffd[] = "/proc/self/fd/";
  39   char fname[sizeof (selffd) + 3 * sizeof (int)];
  40   fname[sizeof (fname) - 1] = '\0';
  41   char *cp = _itoa_word ((unsigned int) fd, fname + sizeof (fname) - 1, 10, 0);
  42   cp = memcpy (cp - sizeof (selffd) + 1, selffd, sizeof (selffd) - 1);
  43
  44   int result;
  45 #ifdef __NR_utimes
  46   result = INLINE_SYSCALL (utimes, 2, cp, tvp);
  47 # ifndef __ASSUME_UTIMES
  48   if (result == -1 && errno == ENOSYS)
  49 # endif
  50 #endif
  51     {
  52       /* The utimes() syscall does not exist or is not available in the
  53          used kernel.  Use utime().  For this we have to convert to the
  54          data format utime() expects.  */
  55 #ifndef __ASSUME_UTIMES
  56       struct utimbuf buf;
  57       struct utimbuf *times;
  58
  59       if (tvp != NULL)
  60         {
  61           times = &buf;
  62           buf.actime = tvp[0].tv_sec + (tvp[0].tv_usec + 500000) / 1000000;
  63           buf.modtime = tvp[1].tv_sec + (tvp[1].tv_usec + 500000) / 1000000;
  64         }
  65       else
  66         times = NULL;
  67
  68       result = INLINE_SYSCALL (utime, 2, cp, times);
  69 #endif
  70     }
  71
  72   if (result == -1)
  73     /* Check for errors that result from failing to find /proc.
  74        This means we can't do futimes at all, so return ENOSYS
  75        rather than some confusing error.  */
  76     switch (errno)
  77       {
  78       case EACCES:
  79         if (tvp == NULL)  /* Could be a path problem or a file problem.  */
  80           break;
  81         /*FALLTHROUGH*/
  82       case ELOOP:
  83       case ENAMETOOLONG:
  84       case ENOTDIR:
  85         __set_errno (ENOSYS);
  86         break;
  87
  88       case ENOENT:
  89         /* Validate the file descriptor by letting fcntl set errno to
  90            EBADF if it's bogus.  Otherwise it's a /proc issue.  */
  91 #if !defined __NR_fcntl && defined __NR_fcntl64
  92 # define __NR_fcntl __NR_fcntl64
  93 #endif
  94         if (INLINE_SYSCALL (fcntl, 3, fd, F_GETFD, 0) != -1)
  95           __set_errno (ENOSYS);
  96         break;
  97       }
  98
  99   return result;
 100 }
 101 weak_alias (__futimes, futimes)