binutils/rename.c

   1 /* rename.c -- rename a file, preserving symlinks.
   2    Copyright 1999, 2002 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 2 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., 59 Temple Place - Suite 330, Boston, MA
  19    02111-1307, USA.  */
  20
  21 #include "bfd.h"
  22 #include "bucomm.h"
  23
  24 #include <sys/stat.h>
  25
  26 #ifdef HAVE_GOOD_UTIME_H
  27 #include <utime.h>
  28 #else /* ! HAVE_GOOD_UTIME_H */
  29 #ifdef HAVE_UTIMES
  30 #include <sys/time.h>
  31 #endif /* HAVE_UTIMES */
  32 #endif /* ! HAVE_GOOD_UTIME_H */
  33
  34 /* We need to open the file in binary modes on system where that makes
  35    a difference.  */
  36 #ifndef O_BINARY
  37 #define O_BINARY 0
  38 #endif
  39
  40 static int simple_copy
  41   PARAMS ((const char *, const char *));
  42
  43 /* The number of bytes to copy at once.  */
  44 #define COPY_BUF 8192
  45
  46 /* Copy file FROM to file TO, performing no translations.
  47    Return 0 if ok, -1 if error.  */
  48
  49 static int
  50 simple_copy (from, to)
  51      const char *from;
  52      const char *to;
  53 {
  54   int fromfd, tofd, nread;
  55   int saved;
  56   char buf[COPY_BUF];
  57
  58   fromfd = open (from, O_RDONLY | O_BINARY);
  59   if (fromfd < 0)
  60     return -1;
  61 #ifdef O_CREAT
  62   tofd = open (to, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0777);
  63 #else
  64   tofd = creat (to, 0777);
  65 #endif
  66   if (tofd < 0)
  67     {
  68       saved = errno;
  69       close (fromfd);
  70       errno = saved;
  71       return -1;
  72     }
  73   while ((nread = read (fromfd, buf, sizeof buf)) > 0)
  74     {
  75       if (write (tofd, buf, nread) != nread)
  76         {
  77           saved = errno;
  78           close (fromfd);
  79           close (tofd);
  80           errno = saved;
  81           return -1;
  82         }
  83     }
  84   saved = errno;
  85   close (fromfd);
  86   close (tofd);
  87   if (nread < 0)
  88     {
  89       errno = saved;
  90       return -1;
  91     }
  92   return 0;
  93 }
  94
  95 /* Set the times of the file DESTINATION to be the same as those in
  96    STATBUF.  */
  97
  98 void
  99 set_times (destination, statbuf)
 100      const char *destination;
 101      const struct stat *statbuf;
 102 {
 103   int result;
 104
 105   {
 106 #ifdef HAVE_GOOD_UTIME_H
 107     struct utimbuf tb;
 108
 109     tb.actime = statbuf->st_atime;
 110     tb.modtime = statbuf->st_mtime;
 111     result = utime (destination, &tb);
 112 #else /* ! HAVE_GOOD_UTIME_H */
 113 #ifndef HAVE_UTIMES
 114     long tb[2];
 115
 116     tb[0] = statbuf->st_atime;
 117     tb[1] = statbuf->st_mtime;
 118     result = utime (destination, tb);
 119 #else /* HAVE_UTIMES */
 120     struct timeval tv[2];
 121
 122     tv[0].tv_sec = statbuf->st_atime;
 123     tv[0].tv_usec = 0;
 124     tv[1].tv_sec = statbuf->st_mtime;
 125     tv[1].tv_usec = 0;
 126     result = utimes (destination, tv);
 127 #endif /* HAVE_UTIMES */
 128 #endif /* ! HAVE_GOOD_UTIME_H */
 129   }
 130
 131   if (result != 0)
 132     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
 133 }
 134
 135 #ifndef S_ISLNK
 136 #ifdef S_IFLNK
 137 #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
 138 #else
 139 #define S_ISLNK(m) 0
 140 #define lstat stat
 141 #endif
 142 #endif
 143
 144 /* Rename FROM to TO, copying if TO is a link.
 145    Return 0 if ok, -1 if error.  */
 146
 147 int
 148 smart_rename (from, to, preserve_dates)
 149      const char *from;
 150      const char *to;
 151      int preserve_dates;
 152 {
 153   bfd_boolean exists;
 154   struct stat s;
 155   int ret = 0;
 156
 157   exists = lstat (to, &s) == 0;
 158
 159 #if defined (_WIN32) && !defined (__CYGWIN32__)
 160   /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
 161      fail instead.  Also, chown is not present.  */
 162
 163   if (exists)
 164     remove (to);
 165
 166   ret = rename (from, to);
 167   if (ret != 0)
 168     {
 169       /* We have to clean up here.  */
 170
 171       non_fatal (_("%s: rename: %s"), to, strerror (errno));
 172       unlink (from);
 173     }
 174 #else
 175   /* Use rename only if TO is not a symbolic link and has
 176      only one hard link.  */
 177   if (! exists || (!S_ISLNK (s.st_mode) && s.st_nlink == 1))
 178     {
 179       ret = rename (from, to);
 180       if (ret == 0)
 181         {
 182           if (exists)
 183             {
 184               /* Try to preserve the permission bits and ownership of
 185                  TO.  First get the mode right except for the setuid
 186                  bit.  Then change the ownership.  Then fix the setuid
 187                  bit.  We do the chmod before the chown because if the
 188                  chown succeeds, and we are a normal user, we won't be
 189                  able to do the chmod afterward.  We don't bother to
 190                  fix the setuid bit first because that might introduce
 191                  a fleeting security problem, and because the chown
 192                  will clear the setuid bit anyhow.  We only fix the
 193                  setuid bit if the chown succeeds, because we don't
 194                  want to introduce an unexpected setuid file owned by
 195                  the user running objcopy.  */
 196               chmod (to, s.st_mode & 0777);
 197               if (chown (to, s.st_uid, s.st_gid) >= 0)
 198                 chmod (to, s.st_mode & 07777);
 199             }
 200         }
 201       else
 202         {
 203           /* We have to clean up here.  */
 204           non_fatal (_("%s: rename: %s"), to, strerror (errno));
 205           unlink (from);
 206         }
 207     }
 208   else
 209     {
 210       ret = simple_copy (from, to);
 211       if (ret != 0)
 212         non_fatal (_("%s: simple_copy: %s"), to, strerror (errno));
 213
 214       if (preserve_dates)
 215         set_times (to, &s);
 216       unlink (from);
 217     }
 218 #endif /* _WIN32 && !__CYGWIN32__ */
 219
 220   return ret;
 221 }