binutils/rename.c

   1 /* rename.c -- rename a file, preserving symlinks.
   2    Copyright (C) 1999-2021 Free Software Foundation, Inc.
   3
   4    This file is part of GNU Binutils.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23 #include "bucomm.h"
  24
  25 #ifdef HAVE_GOOD_UTIME_H
  26 #include <utime.h>
  27 #elif defined HAVE_UTIMES
  28 #include <sys/time.h>
  29 #endif
  30
  31 /* The number of bytes to copy at once.  */
  32 #define COPY_BUF 8192
  33
  34 /* Copy file FROMFD to file TO, performing no translations.
  35    Return 0 if ok, -1 if error.  */
  36
  37 static int
  38 simple_copy (int fromfd, const char *to, struct stat *target_stat)
  39 {
  40   int tofd, nread;
  41   int saved;
  42   char buf[COPY_BUF];
  43
  44   if (fromfd < 0
  45       || lseek (fromfd, 0, SEEK_SET) != 0)
  46     return -1;
  47
  48   tofd = open (to, O_WRONLY | O_TRUNC | O_BINARY);
  49   if (tofd < 0)
  50     {
  51       saved = errno;
  52       close (fromfd);
  53       errno = saved;
  54       return -1;
  55     }
  56
  57   while ((nread = read (fromfd, buf, sizeof buf)) > 0)
  58     {
  59       if (write (tofd, buf, nread) != nread)
  60         {
  61           saved = errno;
  62           close (fromfd);
  63           close (tofd);
  64           errno = saved;
  65           return -1;
  66         }
  67     }
  68
  69   saved = errno;
  70
  71 #if !defined (_WIN32) || defined (__CYGWIN32__)
  72   /* Writing to a setuid/setgid file may clear S_ISUID and S_ISGID.
  73      Try to restore them, ignoring failure.  */
  74   if (target_stat != NULL)
  75     fchmod (tofd, target_stat->st_mode);
  76 #endif
  77
  78   close (fromfd);
  79   close (tofd);
  80   if (nread < 0)
  81     {
  82       errno = saved;
  83       return -1;
  84     }
  85   return 0;
  86 }
  87
  88 /* Set the times of the file DESTINATION to be the same as those in
  89    STATBUF.  */
  90
  91 void
  92 set_times (const char *destination, const struct stat *statbuf)
  93 {
  94   int result;
  95 #ifdef HAVE_GOOD_UTIME_H
  96   struct utimbuf tb;
  97
  98   tb.actime = statbuf->st_atime;
  99   tb.modtime = statbuf->st_mtime;
 100   result = utime (destination, &tb);
 101 #elif defined HAVE_UTIMES
 102   struct timeval tv[2];
 103
 104   tv[0].tv_sec = statbuf->st_atime;
 105   tv[0].tv_usec = 0;
 106   tv[1].tv_sec = statbuf->st_mtime;
 107   tv[1].tv_usec = 0;
 108   result = utimes (destination, tv);
 109 #else
 110   long tb[2];
 111
 112   tb[0] = statbuf->st_atime;
 113   tb[1] = statbuf->st_mtime;
 114   result = utime (destination, tb);
 115 #endif
 116
 117   if (result != 0)
 118     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
 119 }
 120
 121 /* Copy FROM to TO.  TARGET_STAT has the file status that, if non-NULL,
 122    is used to fix up timestamps.  Return 0 if ok, -1 if error.
 123    At one time this function renamed files, but file permissions are
 124    tricky to update given the number of different schemes used by
 125    various systems.  So now we just copy.  */
 126
 127 int
 128 smart_rename (const char *from, const char *to, int fromfd,
 129               struct stat *target_stat, bfd_boolean preserve_dates)
 130 {
 131   int ret;
 132
 133   ret = simple_copy (fromfd, to, target_stat);
 134   if (ret != 0)
 135     non_fatal (_("unable to copy file '%s'; reason: %s"),
 136                to, strerror (errno));
 137
 138   if (preserve_dates)
 139     set_times (to, target_stat);
 140   unlink (from);
 141
 142   return ret;
 143 }