contrib/tar/lib/utime.c

   1 /* Copyright (C) 1998, 2001 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 "full-write.h"
  31 #include "safe-read.h"
  32
  33 /* Some systems (even some that do have <utime.h>) don't declare this
  34    structure anywhere.  */
  35 #ifndef HAVE_STRUCT_UTIMBUF
  36 struct utimbuf
  37 {
  38   long actime;
  39   long modtime;
  40 };
  41 #endif
  42
  43 /* Emulate utime (file, NULL) for systems (like 4.3BSD) that do not
  44    interpret it to set the access and modification times of FILE to
  45    the current time.  Return 0 if successful, -1 if not. */
  46
  47 static int
  48 utime_null (const char *file)
  49 {
  50 #if HAVE_UTIMES_NULL
  51   return utimes (file, 0);
  52 #else
  53   int fd;
  54   char c;
  55   int status = 0;
  56   struct stat sb;
  57
  58   fd = open (file, O_RDWR);
  59   if (fd < 0
  60       || fstat (fd, &sb) < 0
  61       || safe_read (fd, &c, sizeof c) < 0
  62       || lseek (fd, (off_t) 0, SEEK_SET) < 0
  63       || full_write (fd, &c, sizeof c) != sizeof c
  64       /* Maybe do this -- it's necessary on SunOS4.1.3 with some combination
  65          of patches, but that system doesn't use this code: it has utimes.
  66          || fsync (fd) < 0
  67       */
  68       || ftruncate (fd, st.st_size) < 0
  69       || close (fd) < 0)
  70     status = -1;
  71   return status;
  72 #endif
  73 }
  74
  75 int
  76 rpl_utime (const char *file, const struct utimbuf *times)
  77 {
  78   if (times)
  79     return utime (file, times);
  80
  81   return utime_null (file);
  82 }