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,
  39              struct stat *target_stat ATTRIBUTE_UNUSED)
  40 {
  41   int tofd, nread;
  42   int saved;
  43   char buf[COPY_BUF];
  44
  45   if (fromfd < 0
  46       || lseek (fromfd, 0, SEEK_SET) != 0)
  47     return -1;
  48
  49   tofd = open (to, O_WRONLY | O_TRUNC | O_BINARY);
  50   if (tofd < 0)
  51     {
  52       saved = errno;
  53       close (fromfd);
  54       errno = saved;
  55       return -1;
  56     }
  57
  58   while ((nread = read (fromfd, buf, sizeof buf)) > 0)
  59     {
  60       if (write (tofd, buf, nread) != nread)
  61         {
  62           saved = errno;
  63           close (fromfd);
  64           close (tofd);
  65           errno = saved;
  66           return -1;
  67         }
  68     }
  69
  70   saved = errno;
  71
  72 #if !defined (_WIN32) || defined (__CYGWIN32__)
  73   /* Writing to a setuid/setgid file may clear S_ISUID and S_ISGID.
  74      Try to restore them, ignoring failure.  */
  75   if (target_stat != NULL)
  76     fchmod (tofd, target_stat->st_mode);
  77 #endif
  78
  79   close (fromfd);
  80   close (tofd);
  81   if (nread < 0)
  82     {
  83       errno = saved;
  84       return -1;
  85     }
  86   return 0;
  87 }
  88
  89 /* Set the times of the file DESTINATION to be the same as those in
  90    STATBUF.  */
  91
  92 void
  93 set_times (const char *destination, const struct stat *statbuf)
  94 {
  95   int result;
  96 #ifdef HAVE_GOOD_UTIME_H
  97   struct utimbuf tb;
  98
  99   tb.actime = statbuf->st_atime;
 100   tb.modtime = statbuf->st_mtime;
 101   result = utime (destination, &tb);
 102 #elif defined HAVE_UTIMES
 103   struct timeval tv[2];
 104
 105   tv[0].tv_sec = statbuf->st_atime;
 106   tv[0].tv_usec = 0;
 107   tv[1].tv_sec = statbuf->st_mtime;
 108   tv[1].tv_usec = 0;
 109   result = utimes (destination, tv);
 110 #else
 111   long tb[2];
 112
 113   tb[0] = statbuf->st_atime;
 114   tb[1] = statbuf->st_mtime;
 115   result = utime (destination, tb);
 116 #endif
 117
 118   if (result != 0)
 119     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
 120 }
 121
 122 /* Copy FROM to TO.  TARGET_STAT has the file status that, if non-NULL,
 123    is used to fix up timestamps.  Return 0 if ok, -1 if error.
 124    At one time this function renamed files, but file permissions are
 125    tricky to update given the number of different schemes used by
 126    various systems.  So now we just copy.  */
 127
 128 int
 129 smart_rename (const char *from, const char *to, int fromfd,
 130               struct stat *target_stat, bfd_boolean preserve_dates)
 131 {
 132   int ret;
 133
 134   ret = simple_copy (fromfd, to, target_stat);
 135   if (ret != 0)
 136     non_fatal (_("unable to copy file '%s'; reason: %s"),
 137                to, strerror (errno));
 138
 139   if (preserve_dates)
 140     set_times (to, target_stat);
 141   unlink (from);
 142
 143   return ret;
 144 }