sysdeps/unix/sysv/linux/futimesat.c

   1 /* Copyright (C) 2005-2014 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <fcntl.h>
  20 #include <stddef.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <utime.h>
  24 #include <sys/time.h>
  25 #include <sysdep.h>
  26 #include <kernel-features.h>
  27
  28
  29 /* Change the access time of FILE relative to FD to TVP[0] and
  30    the modification time of FILE to TVP[1].  */
  31 int
  32 futimesat (fd, file, tvp)
  33      int fd;
  34      const char *file;
  35      const struct timeval tvp[2];
  36 {
  37   int result;
  38
  39 #ifdef __NR_futimesat
  40 # ifndef __ASSUME_ATFCTS
  41   if (__have_atfcts >= 0)
  42 # endif
  43     {
  44       if (file == NULL)
  45         return __futimes (fd, tvp);
  46
  47       result = INLINE_SYSCALL (futimesat, 3, fd, file, tvp);
  48 # ifndef __ASSUME_ATFCTS
  49       if (result == -1 && errno == ENOSYS)
  50         __have_atfcts = -1;
  51       else
  52 # endif
  53         return result;
  54     }
  55 #endif
  56
  57 #ifndef __ASSUME_ATFCTS
  58   char *buf = NULL;
  59
  60   if (file == NULL)
  61     {
  62       static const char procfd[] = "/proc/self/fd/%d";
  63       /* Buffer for the path name we are going to use.  It consists of
  64          - the string /proc/self/fd/
  65          - the file descriptor number.
  66          The final NUL is included in the sizeof.   A bit of overhead
  67          due to the format elements compensates for possible negative
  68          numbers.  */
  69       size_t buflen = sizeof (procfd) + sizeof (int) * 3;
  70       buf = alloca (buflen);
  71
  72       __snprintf (buf, buflen, procfd, fd);
  73       file = buf;
  74     }
  75   else if (fd != AT_FDCWD && file[0] != '/')
  76     {
  77       size_t filelen = strlen (file);
  78       if (__builtin_expect (filelen == 0, 0))
  79         {
  80           __set_errno (ENOENT);
  81           return -1;
  82         }
  83
  84       static const char procfd[] = "/proc/self/fd/%d/%s";
  85       /* Buffer for the path name we are going to use.  It consists of
  86          - the string /proc/self/fd/
  87          - the file descriptor number
  88          - the file name provided.
  89          The final NUL is included in the sizeof.   A bit of overhead
  90          due to the format elements compensates for possible negative
  91          numbers.  */
  92       size_t buflen = sizeof (procfd) + sizeof (int) * 3 + filelen;
  93       buf = alloca (buflen);
  94
  95       __snprintf (buf, buflen, procfd, fd, file);
  96       file = buf;
  97     }
  98
  99   INTERNAL_SYSCALL_DECL (err);
 100
 101 # ifdef __NR_utimes
 102   result = INTERNAL_SYSCALL (utimes, err, 2, file, tvp);
 103   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 104     return result;
 105
 106 #  ifndef __ASSUME_UTIMES
 107   if (INTERNAL_SYSCALL_ERRNO (result, err) != ENOSYS)
 108     goto fail;
 109 #  endif
 110 # endif
 111
 112   /* The utimes() syscall does not exist or is not available in the
 113      used kernel.  Use utime().  For this we have to convert to the
 114      data format utime() expects.  */
 115 # ifndef __ASSUME_UTIMES
 116   struct utimbuf tmp;
 117   struct utimbuf *times;
 118
 119   if (tvp != NULL)
 120     {
 121       times = &tmp;
 122       tmp.actime = tvp[0].tv_sec + tvp[0].tv_usec / 1000000;
 123       tmp.modtime = tvp[1].tv_sec + tvp[1].tv_usec / 1000000;
 124     }
 125   else
 126     times = NULL;
 127
 128   result = INTERNAL_SYSCALL (utime, err, 2, file, times);
 129   if (__builtin_expect (!INTERNAL_SYSCALL_ERROR_P (result, err), 1))
 130     return result;
 131
 132  fail:
 133 # endif
 134
 135   __atfct_seterrno (INTERNAL_SYSCALL_ERRNO (result, err), fd, buf);
 136
 137   return -1;
 138 #endif
 139 }