backup.c

   1 /*
   2    Copyright (C) Andrew Tridgell 1999
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17 */
  18
  19 /* backup handling code */
  20
  21 #include "rsync.h"
  22
  23 extern int verbose;
  24 extern int backup_dir_len;
  25 extern unsigned int backup_dir_remainder;
  26 extern char backup_dir_buf[MAXPATHLEN];
  27 extern char *backup_suffix;
  28 extern char *backup_dir;
  29
  30 extern int am_root;
  31 extern int preserve_devices;
  32 extern int preserve_specials;
  33 extern int preserve_links;
  34 extern int safe_symlinks;
  35
  36 /* make a complete pathname for backup file */
  37 char *get_backup_name(char *fname)
  38 {
  39         if (backup_dir) {
  40                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  41                                fname, backup_suffix, NULL) < backup_dir_remainder)
  42                         return backup_dir_buf;
  43         } else {
  44                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  45                                fname, backup_suffix, NULL) < MAXPATHLEN)
  46                         return backup_dir_buf;
  47         }
  48
  49         rprintf(FERROR, "backup filename too long\n");
  50         return NULL;
  51 }
  52
  53 /* simple backup creates a backup with a suffix in the same directory */
  54 static int make_simple_backup(char *fname)
  55 {
  56         int rename_errno;
  57         char *fnamebak = get_backup_name(fname);
  58
  59         if (!fnamebak)
  60                 return 0;
  61
  62         while (1) {
  63                 if (do_rename(fname, fnamebak) == 0) {
  64                         if (verbose > 1) {
  65                                 rprintf(FINFO, "backed up %s to %s\n",
  66                                         fname, fnamebak);
  67                         }
  68                         break;
  69                 }
  70                 /* cygwin (at least version b19) reports EINVAL */
  71                 if (errno == ENOENT || errno == EINVAL)
  72                         break;
  73
  74                 rename_errno = errno;
  75                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  76                         continue;
  77                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  78                         continue;
  79
  80                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  81                         fname, fnamebak);
  82                 errno = rename_errno;
  83                 return 0;
  84         }
  85
  86         return 1;
  87 }
  88
  89
  90 /****************************************************************************
  91 Create a directory given an absolute path, perms based upon another directory
  92 path
  93 ****************************************************************************/
  94 static int make_bak_dir(char *fullpath)
  95 {
  96         STRUCT_STAT st;
  97         char *rel = fullpath + backup_dir_len;
  98         char *end = rel + strlen(rel);
  99         char *p = end;
 100
 101         while (strncmp(fullpath, "./", 2) == 0)
 102                 fullpath += 2;
 103
 104         /* Try to find an existing dir, starting from the deepest dir. */
 105         while (1) {
 106                 if (--p == fullpath) {
 107                         p += strlen(p);
 108                         goto failure;
 109                 }
 110                 if (*p == '/') {
 111                         *p = '\0';
 112                         if (mkdir_defmode(fullpath) == 0)
 113                                 break;
 114                         if (errno != ENOENT) {
 115                                 rsyserr(FERROR, errno,
 116                                         "make_bak_dir mkdir %s failed",
 117                                         full_fname(fullpath));
 118                                 goto failure;
 119                         }
 120                 }
 121         }
 122
 123         /* Make all the dirs that we didn't find on the way here. */
 124         while (1) {
 125                 if (p >= rel) {
 126                         /* Try to transfer the directory settings of the
 127                          * actual dir that the files are coming from. */
 128                         if (do_stat(rel, &st) < 0) {
 129                                 rsyserr(FERROR, errno,
 130                                         "make_bak_dir stat %s failed",
 131                                         full_fname(rel));
 132                         } else {
 133                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 134                                 do_chmod(fullpath, st.st_mode);
 135                         }
 136                 }
 137                 *p = '/';
 138                 p += strlen(p);
 139                 if (p == end)
 140                         break;
 141                 if (mkdir_defmode(fullpath) < 0) {
 142                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 143                                 full_fname(fullpath));
 144                         goto failure;
 145                 }
 146         }
 147         return 0;
 148
 149   failure:
 150         while (p != end) {
 151                 *p = '/';
 152                 p += strlen(p);
 153         }
 154         return -1;
 155 }
 156
 157 /* robustly move a file, creating new directory structures if necessary */
 158 static int robust_move(char *src, char *dst)
 159 {
 160         if (robust_rename(src, dst, NULL, 0755) < 0
 161          && (errno != ENOENT || make_bak_dir(dst) < 0
 162           || robust_rename(src, dst, NULL, 0755) < 0))
 163                 return -1;
 164         return 0;
 165 }
 166
 167
 168 /* If we have a --backup-dir, then we get here from make_backup().
 169  * We will move the file to be deleted into a parallel directory tree. */
 170 static int keep_backup(char *fname)
 171 {
 172         STRUCT_STAT st;
 173         struct file_struct *file;
 174         char *buf;
 175         int kept = 0;
 176         int ret_code;
 177
 178         /* return if no file to keep */
 179         if (do_lstat(fname, &st) < 0)
 180                 return 1;
 181
 182         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 183                 return 1; /* the file could have disappeared */
 184
 185         if (!(buf = get_backup_name(fname)))
 186                 return 0;
 187
 188         /* Check to see if this is a device file, or link */
 189         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 190          || (preserve_specials && IS_SPECIAL(file->mode))) {
 191                 do_unlink(buf);
 192                 if (do_mknod(buf, file->mode, file->u.rdev) < 0
 193                     && (errno != ENOENT || make_bak_dir(buf) < 0
 194                      || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
 195                         rsyserr(FERROR, errno, "mknod %s failed",
 196                                 full_fname(buf));
 197                 } else if (verbose > 2) {
 198                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 199                                 fname);
 200                 }
 201                 kept = 1;
 202                 do_unlink(fname);
 203         }
 204
 205         if (!kept && S_ISDIR(file->mode)) {
 206                 /* make an empty directory */
 207                 if (do_mkdir(buf, file->mode) < 0
 208                     && (errno != ENOENT || make_bak_dir(buf) < 0
 209                      || do_mkdir(buf, file->mode) < 0)) {
 210                         rsyserr(FINFO, errno, "mkdir %s failed",
 211                                 full_fname(buf));
 212                 }
 213
 214                 ret_code = do_rmdir(fname);
 215                 if (verbose > 2) {
 216                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 217                                 full_fname(fname), ret_code);
 218                 }
 219                 kept = 1;
 220         }
 221
 222 #ifdef SUPPORT_LINKS
 223         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 224                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
 225                         if (verbose) {
 226                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 227                                         full_fname(buf), file->u.link);
 228                         }
 229                         kept = 1;
 230                 } else {
 231                         do_unlink(buf);
 232                         if (do_symlink(file->u.link, buf) < 0
 233                             && (errno != ENOENT || make_bak_dir(buf) < 0
 234                              || do_symlink(file->u.link, buf) < 0)) {
 235                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 236                                         full_fname(buf),
 237                                         file->u.link);
 238                         }
 239                         do_unlink(fname);
 240                         kept = 1;
 241                 }
 242         }
 243 #endif
 244
 245         if (!kept && !S_ISREG(file->mode)) {
 246                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 247                         fname);
 248                 return 1;
 249         }
 250
 251         /* move to keep tree if a file */
 252         if (!kept) {
 253                 if (robust_move(fname, buf) != 0) {
 254                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 255                                 full_fname(fname), buf);
 256                 } else if (st.st_nlink > 1) {
 257                         /* If someone has hard-linked the file into the backup
 258                          * dir, rename() might return success but do nothing! */
 259                         robust_unlink(fname); /* Just in case... */
 260                 }
 261         }
 262         set_file_attrs(buf, file, NULL, 0);
 263         free(file);
 264
 265         if (verbose > 1) {
 266                 rprintf(FINFO, "backed up %s to %s\n",
 267                         fname, buf);
 268         }
 269         return 1;
 270 }
 271
 272
 273 /* main backup switch routine */
 274 int make_backup(char *fname)
 275 {
 276         if (backup_dir)
 277                 return keep_backup(fname);
 278         return make_simple_backup(fname);
 279 }