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 #if defined HAVE_UTIMES
  26 #include <sys/time.h>
  27 #elif defined HAVE_GOOD_UTIME_H
  28 #include <utime.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 /* The following defines and inline functions are copied from gnulib.
  90    FIXME: Use a gnulib import and stat-time.h instead.  */
  91 #if defined HAVE_STRUCT_STAT_ST_ATIM_TV_NSEC
  92 # if defined TYPEOF_STRUCT_STAT_ST_ATIM_IS_STRUCT_TIMESPEC
  93 #  define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim)
  94 # else
  95 #  define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.tv_nsec)
  96 # endif
  97 #elif defined HAVE_STRUCT_STAT_ST_ATIMESPEC_TV_NSEC
  98 # define STAT_TIMESPEC(st, st_xtim) ((st)->st_xtim##espec)
  99 #elif defined HAVE_STRUCT_STAT_ST_ATIMENSEC
 100 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim##ensec)
 101 #elif defined HAVE_STRUCT_STAT_ST_ATIM_ST__TIM_TV_NSEC
 102 # define STAT_TIMESPEC_NS(st, st_xtim) ((st)->st_xtim.st__tim.tv_nsec)
 103 #endif
 104
 105 static inline long int get_stat_atime_ns (struct stat const *) ATTRIBUTE_UNUSED;
 106 static inline long int get_stat_mtime_ns (struct stat const *) ATTRIBUTE_UNUSED;
 107
 108 /* Return the nanosecond component of *ST's access time.  */
 109 static inline long int
 110 get_stat_atime_ns (struct stat const *st ATTRIBUTE_UNUSED)
 111 {
 112 # if defined STAT_TIMESPEC
 113   return STAT_TIMESPEC (st, st_atim).tv_nsec;
 114 # elif defined STAT_TIMESPEC_NS
 115   return STAT_TIMESPEC_NS (st, st_atim);
 116 # else
 117   return 0;
 118 # endif
 119 }
 120
 121 /* Return the nanosecond component of *ST's data modification time.  */
 122 static inline long int
 123 get_stat_mtime_ns (struct stat const *st ATTRIBUTE_UNUSED)
 124 {
 125 # if defined STAT_TIMESPEC
 126   return STAT_TIMESPEC (st, st_mtim).tv_nsec;
 127 # elif defined STAT_TIMESPEC_NS
 128   return STAT_TIMESPEC_NS (st, st_mtim);
 129 # else
 130   return 0;
 131 # endif
 132 }
 133
 134 /* Return *ST's access time.  */
 135 static inline struct timespec
 136 get_stat_atime (struct stat const *st)
 137 {
 138 #ifdef STAT_TIMESPEC
 139   return STAT_TIMESPEC (st, st_atim);
 140 #else
 141   struct timespec t;
 142   t.tv_sec = st->st_atime;
 143   t.tv_nsec = get_stat_atime_ns (st);
 144   return t;
 145 #endif
 146 }
 147
 148 /* Return *ST's data modification time.  */
 149 static inline struct timespec
 150 get_stat_mtime (struct stat const *st)
 151 {
 152 #ifdef STAT_TIMESPEC
 153   return STAT_TIMESPEC (st, st_mtim);
 154 #else
 155   struct timespec t;
 156   t.tv_sec = st->st_mtime;
 157   t.tv_nsec = get_stat_mtime_ns (st);
 158   return t;
 159 #endif
 160 }
 161 /* End FIXME.  */
 162
 163 /* Set the times of the file DESTINATION to be the same as those in
 164    STATBUF.  */
 165
 166 void
 167 set_times (const char *destination, const struct stat *statbuf)
 168 {
 169   int result;
 170 #if defined HAVE_UTIMENSAT
 171   struct timespec times[2];
 172   times[0] = get_stat_atime (statbuf);
 173   times[1] = get_stat_mtime (statbuf);
 174   result = utimensat (AT_FDCWD, destination, times, 0);
 175 #elif defined HAVE_UTIMES
 176   struct timeval tv[2];
 177
 178   tv[0].tv_sec = statbuf->st_atime;
 179   tv[0].tv_usec = get_stat_atime_ns (statbuf) / 1000;
 180   tv[1].tv_sec = statbuf->st_mtime;
 181   tv[1].tv_usec = get_stat_mtime_ns (statbuf) / 1000;
 182   result = utimes (destination, tv);
 183 #elif defined HAVE_GOOD_UTIME_H
 184   struct utimbuf tb;
 185
 186   tb.actime = statbuf->st_atime;
 187   tb.modtime = statbuf->st_mtime;
 188   result = utime (destination, &tb);
 189 #else
 190   long tb[2];
 191
 192   tb[0] = statbuf->st_atime;
 193   tb[1] = statbuf->st_mtime;
 194   result = utime (destination, tb);
 195 #endif
 196
 197   if (result != 0)
 198     non_fatal (_("%s: cannot set time: %s"), destination, strerror (errno));
 199 }
 200
 201 /* Copy FROM to TO.  TARGET_STAT has the file status that, if non-NULL,
 202    is used to fix up timestamps.  Return 0 if ok, -1 if error.
 203    At one time this function renamed files, but file permissions are
 204    tricky to update given the number of different schemes used by
 205    various systems.  So now we just copy.  */
 206
 207 int
 208 smart_rename (const char *from, const char *to, int fromfd,
 209               struct stat *target_stat, bool preserve_dates)
 210 {
 211   int ret = 0;
 212
 213   if (to != from)
 214     {
 215       ret = simple_copy (fromfd, to, target_stat);
 216       if (ret != 0)
 217         non_fatal (_("unable to copy file '%s'; reason: %s"),
 218                    to, strerror (errno));
 219       unlink (from);
 220     }
 221
 222   if (preserve_dates)
 223     set_times (to, target_stat);
 224
 225   return ret;
 226 }