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   char *buf = NULL;
  39
  40   if (file == NULL)
  41     {
  42       static const char procfd[] = "/proc/self/fd/%d";
  43       /* Buffer for the path name we are going to use.  It consists of
  44          - the string /proc/self/fd/
  45          - the file descriptor number.
  46          The final NUL is included in the sizeof.   A bit of overhead
  47          due to the format elements compensates for possible negative
  48          numbers.  */
  49       size_t buflen = sizeof (procfd) + sizeof (int) * 3;
  50       buf = alloca (buflen);
  51
  52       __snprintf (buf, buflen, procfd, fd);
  53       file = buf;
  54     }
  55   else if (fd != AT_FDCWD && file[0] != '/')
  56     {
  57       size_t filelen = strlen (file);
  58       static const char procfd[] = "/proc/self/fd/%d/%s";
  59       /* Buffer for the path name we are going to use.  It consists of
  60          - the string /proc/self/fd/
  61          - the file descriptor number
  62          - the file name provided.
  63          The final NUL is included in the sizeof.   A bit of overhead
  64          due to the format elements compensates for possible negative
  65          numbers.  */
  66       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  67       buf = alloca (buflen);
  68
  69       __snprintf (buf, buflen, procfd, fd, file);
  70       file = buf;
  71     }
  72
  73   int result;
  74   INTERNAL_SYSCALL_DECL (err);
  75
  76 #ifdef __NR_utimes
  77   result = INTERNAL_SYSCALL (utimes, err, 2, file, tvp);
  78   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
  79     return result;
  80
  81 # ifndef __ASSUME_UTIMES
  82   if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
  83     goto fail;
  84 # endif
  85 #endif
  86
  87   /* The utimes() syscall does not exist or is not available in the
  88      used kernel.  Use utime().  For this we have to convert to the
  89      data format utime() expects.  */
  90 #ifndef __ASSUME_UTIMES
  91   struct utimbuf tmp;
  92   struct utimbuf *times;
  93
  94   if (tvp != NULL)
  95     {
  96       times = &tmp;
  97       tmp.actime = tvp[0].tv_sec + tvp[0].tv_usec / 1000000;
  98       tmp.modtime = tvp[1].tv_sec + tvp[1].tv_usec / 1000000;
  99     }
 100   else
 101     times = NULL;
 102
 103   result = INTERNAL_SYSCALL (utime, err, 2, file, times);
 104   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 105     return result;
 106
 107  fail:
 108 #endif
 109
 110   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 111
 112   return -1;
 113 }