lib/utime.c

   1 /* Copyright (C) 1998 Free Software Foundation, Inc.
   2
   3    This program is free software; you can redistribute it and/or modify it
   4    under the terms of the GNU General Public License as published by the
   5    Free Software Foundation; either version 2, or (at your option) any
   6    later version.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program; if not, write to the Free Software Foundation,
  15    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  16
  17 /* derived from a function in touch.c */
  18
  19 #ifdef HAVE_CONFIG_H
  20 # include <config.h>
  21 #endif
  22 #undef utime
  23
  24 #include <sys/types.h>
  25
  26 #ifdef HAVE_UTIME_H
  27 # include <utime.h>
  28 #endif
  29
  30 #include "safe-read.h"
  31
  32 /* Some systems (even some that do have <utime.h>) don't declare this
  33    structure anywhere.  */
  34 #ifndef HAVE_STRUCT_UTIMBUF
  35 struct utimbuf
  36 {
  37   long actime;
  38   long modtime;
  39 };
  40 #endif
  41
  42 /* Emulate utime (file, NULL) for systems (like 4.3BSD) that do not
  43    interpret it to set the access and modification times of FILE to
  44    the current time.  Return 0 if successful, -1 if not. */
  45
  46 static int
  47 utime_null (const char *file)
  48 {
  49 #if HAVE_UTIMES_NULL
  50   return utimes (file, 0);
  51 #else
  52   int fd;
  53   char c;
  54   int status = 0;
  55   struct stat sb;
  56
  57   fd = open (file, O_RDWR);
  58   if (fd < 0
  59       || fstat (fd, &sb) < 0
  60       || safe_read (fd, &c, sizeof (char)) < 0
  61       || lseek (fd, (off_t) 0, SEEK_SET) < 0
  62       || full_write (fd, &c, sizeof (char)) < 0
  63       /* Maybe do this -- it's necessary on SunOS4.1.3 with some combination
  64          of patches, but that system doesn't use this code: it has utimes.
  65          || fsync (fd) < 0
  66       */
  67       || ftruncate (fd, st.st_size) < 0
  68       || close (fd) < 0)
  69     status = -1;
  70   return status;
  71 #endif
  72 }
  73
  74 int
  75 rpl_utime (const char *file, const struct utimbuf *times)
  76 {
  77   if (times)
  78     return utime (file, times);
  79
  80   return utime_null (file);
  81 }