lib/copy-file.c

   1 /* Copying of files.
   2    Copyright (C) 2001-2003, 2006-2007, 2009-2017 Free Software Foundation, Inc.
   3    Written by Bruno Haible <haible@clisp.cons.org>, 2001.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #include "copy-file.h"
  23
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28 #include <sys/stat.h>
  29 #include <unistd.h>
  30
  31 #include "error.h"
  32 #include "ignore-value.h"
  33 #include "safe-read.h"
  34 #include "full-write.h"
  35 #include "stat-time.h"
  36 #include "utimens.h"
  37 #include "acl.h"
  38 #include "binary-io.h"
  39 #include "quote.h"
  40 #include "gettext.h"
  41 #include "xalloc.h"
  42
  43 #define _(str) gettext (str)
  44
  45 enum { IO_SIZE = 32 * 1024 };
  46
  47 int
  48 qcopy_file_preserving (const char *src_filename, const char *dest_filename)
  49 {
  50   int err = 0;
  51   int src_fd;
  52   struct stat statbuf;
  53   int mode;
  54   int dest_fd;
  55   char *buf = xmalloc (IO_SIZE);
  56
  57   src_fd = open (src_filename, O_RDONLY | O_BINARY);
  58   if (src_fd < 0)
  59     {
  60       err = GL_COPY_ERR_OPEN_READ;
  61       goto error;
  62     }
  63   if (fstat (src_fd, &statbuf) < 0)
  64     {
  65       err = GL_COPY_ERR_OPEN_READ;
  66       goto error_src;
  67     }
  68
  69   mode = statbuf.st_mode & 07777;
  70
  71   dest_fd = open (dest_filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0600);
  72   if (dest_fd < 0)
  73     {
  74       err = GL_COPY_ERR_OPEN_BACKUP_WRITE;
  75       goto error_src;
  76     }
  77
  78   /* Copy the file contents.  */
  79   for (;;)
  80     {
  81       size_t n_read = safe_read (src_fd, buf, IO_SIZE);
  82       if (n_read == SAFE_READ_ERROR)
  83         {
  84           err = GL_COPY_ERR_READ;
  85           goto error_src_dest;
  86         }
  87       if (n_read == 0)
  88         break;
  89
  90       if (full_write (dest_fd, buf, n_read) < n_read)
  91         {
  92           err = GL_COPY_ERR_WRITE;
  93           goto error_src_dest;
  94         }
  95     }
  96
  97   free (buf);
  98   buf = NULL; /* To avoid double free in error case.  */
  99
 100 #if !USE_ACL
 101   if (close (dest_fd) < 0)
 102     {
 103       err = GL_COPY_ERR_WRITE;
 104       goto error_src;
 105     }
 106   if (close (src_fd) < 0)
 107     {
 108       err = GL_COPY_ERR_AFTER_READ;
 109       goto error;
 110     }
 111 #endif
 112
 113   /* Preserve the access and modification times.  */
 114   {
 115     struct timespec ts[2];
 116
 117     ts[0] = get_stat_atime (&statbuf);
 118     ts[1] = get_stat_mtime (&statbuf);
 119     utimens (dest_filename, ts);
 120   }
 121
 122 #if HAVE_CHOWN
 123   /* Preserve the owner and group.  */
 124   ignore_value (chown (dest_filename, statbuf.st_uid, statbuf.st_gid));
 125 #endif
 126
 127   /* Preserve the access permissions.  */
 128 #if USE_ACL
 129   switch (qcopy_acl (src_filename, src_fd, dest_filename, dest_fd, mode))
 130     {
 131     case -2:
 132       err = GL_COPY_ERR_GET_ACL;
 133       goto error_src_dest;
 134     case -1:
 135       err = GL_COPY_ERR_SET_ACL;
 136       goto error_src_dest;
 137     }
 138 #else
 139   chmod (dest_filename, mode);
 140 #endif
 141
 142 #if USE_ACL
 143   if (close (dest_fd) < 0)
 144     {
 145       err = GL_COPY_ERR_WRITE;
 146       goto error_src;
 147     }
 148   if (close (src_fd) < 0)
 149     {
 150       err = GL_COPY_ERR_AFTER_READ;
 151       goto error;
 152     }
 153 #endif
 154
 155   return 0;
 156
 157  error_src_dest:
 158   close (dest_fd);
 159  error_src:
 160   close (src_fd);
 161  error:
 162   free (buf);
 163   return err;
 164 }
 165
 166 void
 167 copy_file_preserving (const char *src_filename, const char *dest_filename)
 168 {
 169   switch (qcopy_file_preserving (src_filename, dest_filename))
 170     {
 171     case 0:
 172       return;
 173
 174     case GL_COPY_ERR_OPEN_READ:
 175       error (EXIT_FAILURE, errno, _("error while opening %s for reading"),
 176              quote (src_filename));
 177
 178     case GL_COPY_ERR_OPEN_BACKUP_WRITE:
 179       error (EXIT_FAILURE, errno, _("cannot open backup file %s for writing"),
 180              quote (dest_filename));
 181
 182     case GL_COPY_ERR_READ:
 183       error (EXIT_FAILURE, errno, _("error reading %s"),
 184              quote (src_filename));
 185
 186     case GL_COPY_ERR_WRITE:
 187       error (EXIT_FAILURE, errno, _("error writing %s"),
 188              quote (dest_filename));
 189
 190     case GL_COPY_ERR_AFTER_READ:
 191       error (EXIT_FAILURE, errno, _("error after reading %s"),
 192              quote (src_filename));
 193
 194     case GL_COPY_ERR_GET_ACL:
 195       error (EXIT_FAILURE, errno, "%s", quote (src_filename));
 196
 197     case GL_COPY_ERR_SET_ACL:
 198       error (EXIT_FAILURE, errno, _("preserving permissions for %s"),
 199              quote (dest_filename));
 200
 201     default:
 202       abort ();
 203     }
 204 }