sysdeps/unix/sysv/linux/futimesat.c

   1 /* Copyright (C) 2005, 2006 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <utime.h>
  25 #include <sys/time.h>
  26 #include <sysdep.h>
  27 #include <kernel-features.h>
  28
  29
  30 /* Change the access time of FILE relative to FD to TVP[0] and
  31    the modification time of FILE to TVP[1].  */
  32 int
  33 futimesat (fd, file, tvp)
  34      int fd;
  35      const char *file;
  36      const struct timeval tvp[2];
  37 {
  38   int result;
  39
  40   if (file == NULL)
  41     return __futimes (fd, tvp);
  42
  43 #ifdef __NR_futimesat
  44 # ifndef __ASSUME_ATFCTS
  45   if (__have_atfcts >= 0)
  46 # endif
  47     {
  48       result = INLINE_SYSCALL (futimesat, 3, fd, file, tvp);
  49 # ifndef __ASSUME_ATFCTS
  50       if (result == -1 && errno == ENOSYS)
  51         __have_atfcts = -1;
  52       else
  53 # endif
  54         return result;
  55     }
  56 #endif
  57
  58 #ifndef __ASSUME_ATFCTS
  59   char *buf = NULL;
  60
  61   if (fd != AT_FDCWD && file[0] != '/')
  62     {
  63       size_t filelen = strlen (file);
  64       static const char procfd[] = "/proc/self/fd/%d/%s";
  65       /* Buffer for the path name we are going to use.  It consists of
  66          - the string /proc/self/fd/
  67          - the file descriptor number
  68          - the file name provided.
  69          The final NUL is included in the sizeof.   A bit of overhead
  70          due to the format elements compensates for possible negative
  71          numbers.  */
  72       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  73       buf = alloca (buflen);
  74
  75       __snprintf (buf, buflen, procfd, fd, file);
  76       file = buf;
  77     }
  78
  79   INTERNAL_SYSCALL_DECL (err);
  80
  81 # ifdef __NR_utimes
  82   result = INTERNAL_SYSCALL (utimes, err, 2, file, tvp);
  83   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  84     return result;
  85
  86 #  ifndef __ASSUME_UTIMES
  87   if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
  88     goto fail;
  89 #  endif
  90 # endif
  91
  92   /* The utimes() syscall does not exist or is not available in the
  93      used kernel.  Use utime().  For this we have to convert to the
  94      data format utime() expects.  */
  95 # ifndef __ASSUME_UTIMES
  96   struct utimbuf tmp;
  97   struct utimbuf *times;
  98
  99   if (tvp != NULL)
 100     {
 101       times = &tmp;
 102       tmp.actime = tvp[0].tv_sec + tvp[0].tv_usec / 1000000;
 103       tmp.modtime = tvp[1].tv_sec + tvp[1].tv_usec / 1000000;
 104     }
 105   else
 106     times = NULL;
 107
 108   result = INTERNAL_SYSCALL (utime, err, 2, file, times);
 109   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 110     return result;
 111
 112  fail:
 113 # endif
 114
 115   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 116
 117   return -1;
 118 #endif
 119 }