1: /* rename.c -- rename a file, preserving symlinks.
    2:    Copyright 1999, 2002, 2003, 2007 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: #include <sys/stat.h>
   26: 
   27: #ifdef HAVE_GOOD_UTIME_H
   28: #include <utime.h>
   29: #else /* ! HAVE_GOOD_UTIME_H */
   30: #ifdef HAVE_UTIMES
   31: #include <sys/time.h>
   32: #endif /* HAVE_UTIMES */
   33: #endif /* ! HAVE_GOOD_UTIME_H */
   34: 
   35: /* We need to open the file in binary modes on system where that makes
   36:    a difference.  */
   37: #ifndef O_BINARY
   38: #define O_BINARY 0
   39: #endif
   40: 
   41: #if ! defined (_WIN32) || defined (__CYGWIN32__)
   42: static int simple_copy (const char *, const char *);
   43: 
   44: /* The number of bytes to copy at once.  */
   45: #define COPY_BUF 8192
   46: 
   47: /* Copy file FROM to file TO, performing no translations.
   48:    Return 0 if ok, -1 if error.  */
   49: 
   50: static int
   51: simple_copy (const char *from, const char *to)
   52: {
   53:   int fromfd, tofd, nread;
   54:   int saved;
   55:   char buf[COPY_BUF];
   56: 
   57:   fromfd = open (from, O_RDONLY | O_BINARY);
   58:   if (fromfd < 0)
   59:     return -1;
   60: #ifdef O_CREAT
   61:   tofd = open (to, O_CREAT | O_WRONLY | O_TRUNC | O_BINARY, 0777);
   62: #else
   63:   tofd = creat (to, 0777);
   64: #endif
   65:   if (tofd < 0)
   66:     {
   67:       saved = errno;
   68:       close (fromfd);
   69:       errno = saved;
   70:       return -1;
   71:     }
   72:   while ((nread = read (fromfd, buf, sizeof buf)) > 0)
   73:     {
   74:       if (write (tofd, buf, nread) != nread)
   75:         {
   76:           saved = errno;
   77:           close (fromfd);
   78:           close (tofd);
   79:           errno = saved;
   80:           return -1;
   81:         }
   82:     }
   83:   saved = errno;
   84:   close (fromfd);
   85:   close (tofd);
   86:   if (nread < 0)
   87:     {
   88:       errno = saved;
   89:       return -1;
   90:     }
   91:   return 0;
   92: }
   93: #endif /* __CYGWIN32__ or not _WIN32 */
   94: 
   95: /* Set the times of the file DESTINATION to be the same as those in
   96:    STATBUF.  */
   97: 
   98: void
   99: set_times (const char *destination, const struct stat *statbuf)
  100: {
  101:   int result;
  102: 
  103:   {
  104: #ifdef HAVE_GOOD_UTIME_H
  105:     struct utimbuf tb;
  106: 
  107:     tb.actime = statbuf->st_atime;
  108:     tb.modtime = statbuf->st_mtime;
  109:     result = utime (destination, &tb);
  110: #else /* ! HAVE_GOOD_UTIME_H */
  111: #ifndef HAVE_UTIMES
  112:     long tb[2];
  113: 
  114:     tb[0] = statbuf->st_atime;
  115:     tb[1] = statbuf->st_mtime;
  116:     result = utime (destination, tb);
  117: #else /* HAVE_UTIMES */
  118:     struct timeval tv[2];
  119: 
  120:     tv[0].tv_sec = statbuf->st_atime;
  121:     tv[0].tv_usec = 0;
  122:     tv[1].tv_sec = statbuf->st_mtime;
  123:     tv[1].tv_usec = 0;
  124:     result = utimes (destination, tv);
  125: #endif /* HAVE_UTIMES */
  126: #endif /* ! HAVE_GOOD_UTIME_H */
  127:   }
  128: 
  129:   if (result != 0)
  130:     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
  131: }
  132: 
  133: #ifndef S_ISLNK
  134: #ifdef S_IFLNK
  135: #define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
  136: #else
  137: #define S_ISLNK(m) 0
  138: #define lstat stat
  139: #endif
  140: #endif
  141: 
  142: /* Rename FROM to TO, copying if TO is a link.
  143:    Return 0 if ok, -1 if error.  */
  144: 
  145: int
  146: smart_rename (const char *from, const char *to, int preserve_dates ATTRIBUTE_UNUSED)
  147: {
  148:   bfd_boolean exists;
  149:   struct stat s;
  150:   int ret = 0;
  151: 
  152:   exists = lstat (to, &s) == 0;
  153: 
  154: #if defined (_WIN32) && !defined (__CYGWIN32__)
  155:   /* Win32, unlike unix, will not erase `to' in `rename(from, to)' but
  156:      fail instead.  Also, chown is not present.  */
  157: 
  158:   if (exists)
  159:     remove (to);
  160: 
  161:   ret = rename (from, to);
  162:   if (ret != 0)
  163:     {
  164:       /* We have to clean up here.  */
  165:       non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
  166:       unlink (from);
  167:     }
  168: #else
  169:   /* Use rename only if TO is not a symbolic link and has
  170:      only one hard link, and we have permission to write to it.  */
  171:   if (! exists
  172:       || (!S_ISLNK (s.st_mode)
  173:           && S_ISREG (s.st_mode)
  174:           && (s.st_mode & S_IWUSR)
  175:           && s.st_nlink == 1)
  176:       )
  177:     {
  178:       ret = rename (from, to);
  179:       if (ret == 0)
  180:         {
  181:           if (exists)
  182:             {
  183:               /* Try to preserve the permission bits and ownership of
  184:                  TO.  First get the mode right except for the setuid
  185:                  bit.  Then change the ownership.  Then fix the setuid
  186:                  bit.  We do the chmod before the chown because if the
  187:                  chown succeeds, and we are a normal user, we won't be
  188:                  able to do the chmod afterward.  We don't bother to
  189:                  fix the setuid bit first because that might introduce
  190:                  a fleeting security problem, and because the chown
  191:                  will clear the setuid bit anyhow.  We only fix the
  192:                  setuid bit if the chown succeeds, because we don't
  193:                  want to introduce an unexpected setuid file owned by
  194:                  the user running objcopy.  */
  195:               chmod (to, s.st_mode & 0777);
  196:               if (chown (to, s.st_uid, s.st_gid) >= 0)
  197:                 chmod (to, s.st_mode & 07777);
  198:             }
  199:         }
  200:       else
  201:         {
  202:           /* We have to clean up here.  */
  203:           non_fatal (_("unable to rename '%s' reason: %s"), to, strerror (errno));
  204:           unlink (from);
  205:         }
  206:     }
  207:   else
  208:     {
  209:       ret = simple_copy (from, to);
  210:       if (ret != 0)
  211:         non_fatal (_("unable to copy file '%s' reason: %s"), to, strerror (errno));
  212: 
  213:       if (preserve_dates)
  214:         set_times (to, &s);
  215:       unlink (from);
  216:     }
  217: #endif /* _WIN32 && !__CYGWIN32__ */
  218: 
  219:   return ret;
  220: }