backup.c

   1 /*
   2  * Backup handling code.
   3  *
   4  * Copyright (C) 1999 Andrew Tridgell
   5  * Copyright (C) 2003, 2004, 2005, 2006 Wayne Davison
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  20  */
  21
  22 #include "rsync.h"
  23
  24 extern int verbose;
  25 extern int backup_dir_len;
  26 extern unsigned int backup_dir_remainder;
  27 extern char backup_dir_buf[MAXPATHLEN];
  28 extern char *backup_suffix;
  29 extern char *backup_dir;
  30
  31 extern int am_root;
  32 extern int preserve_devices;
  33 extern int preserve_specials;
  34 extern int preserve_links;
  35 extern int safe_symlinks;
  36
  37 /* make a complete pathname for backup file */
  38 char *get_backup_name(char *fname)
  39 {
  40         if (backup_dir) {
  41                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  42                                fname, backup_suffix, NULL) < backup_dir_remainder)
  43                         return backup_dir_buf;
  44         } else {
  45                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  46                                fname, backup_suffix, NULL) < MAXPATHLEN)
  47                         return backup_dir_buf;
  48         }
  49
  50         rprintf(FERROR, "backup filename too long\n");
  51         return NULL;
  52 }
  53
  54 /* simple backup creates a backup with a suffix in the same directory */
  55 static int make_simple_backup(char *fname)
  56 {
  57         int rename_errno;
  58         char *fnamebak = get_backup_name(fname);
  59
  60         if (!fnamebak)
  61                 return 0;
  62
  63         while (1) {
  64                 if (do_rename(fname, fnamebak) == 0) {
  65                         if (verbose > 1) {
  66                                 rprintf(FINFO, "backed up %s to %s\n",
  67                                         fname, fnamebak);
  68                         }
  69                         break;
  70                 }
  71                 /* cygwin (at least version b19) reports EINVAL */
  72                 if (errno == ENOENT || errno == EINVAL)
  73                         break;
  74
  75                 rename_errno = errno;
  76                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  77                         continue;
  78                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  79                         continue;
  80
  81                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  82                         fname, fnamebak);
  83                 errno = rename_errno;
  84                 return 0;
  85         }
  86
  87         return 1;
  88 }
  89
  90
  91 /****************************************************************************
  92 Create a directory given an absolute path, perms based upon another directory
  93 path
  94 ****************************************************************************/
  95 static int make_bak_dir(char *fullpath)
  96 {
  97         STRUCT_STAT st;
  98         char *rel = fullpath + backup_dir_len;
  99         char *end = rel + strlen(rel);
 100         char *p = end;
 101
 102         while (strncmp(fullpath, "./", 2) == 0)
 103                 fullpath += 2;
 104
 105         /* Try to find an existing dir, starting from the deepest dir. */
 106         while (1) {
 107                 if (--p == fullpath) {
 108                         p += strlen(p);
 109                         goto failure;
 110                 }
 111                 if (*p == '/') {
 112                         *p = '\0';
 113                         if (mkdir_defmode(fullpath) == 0)
 114                                 break;
 115                         if (errno != ENOENT) {
 116                                 rsyserr(FERROR, errno,
 117                                         "make_bak_dir mkdir %s failed",
 118                                         full_fname(fullpath));
 119                                 goto failure;
 120                         }
 121                 }
 122         }
 123
 124         /* Make all the dirs that we didn't find on the way here. */
 125         while (1) {
 126                 if (p >= rel) {
 127                         /* Try to transfer the directory settings of the
 128                          * actual dir that the files are coming from. */
 129                         if (do_stat(rel, &st) < 0) {
 130                                 rsyserr(FERROR, errno,
 131                                         "make_bak_dir stat %s failed",
 132                                         full_fname(rel));
 133                         } else {
 134                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 135                                 do_chmod(fullpath, st.st_mode);
 136                         }
 137                 }
 138                 *p = '/';
 139                 p += strlen(p);
 140                 if (p == end)
 141                         break;
 142                 if (mkdir_defmode(fullpath) < 0) {
 143                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 144                                 full_fname(fullpath));
 145                         goto failure;
 146                 }
 147         }
 148         return 0;
 149
 150   failure:
 151         while (p != end) {
 152                 *p = '/';
 153                 p += strlen(p);
 154         }
 155         return -1;
 156 }
 157
 158 /* robustly move a file, creating new directory structures if necessary */
 159 static int robust_move(char *src, char *dst)
 160 {
 161         if (robust_rename(src, dst, NULL, 0755) < 0
 162          && (errno != ENOENT || make_bak_dir(dst) < 0
 163           || robust_rename(src, dst, NULL, 0755) < 0))
 164                 return -1;
 165         return 0;
 166 }
 167
 168
 169 /* If we have a --backup-dir, then we get here from make_backup().
 170  * We will move the file to be deleted into a parallel directory tree. */
 171 static int keep_backup(char *fname)
 172 {
 173         STRUCT_STAT st;
 174         struct file_struct *file;
 175         char *buf;
 176         int kept = 0;
 177         int ret_code;
 178
 179         /* return if no file to keep */
 180         if (do_lstat(fname, &st) < 0)
 181                 return 1;
 182
 183         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 184                 return 1; /* the file could have disappeared */
 185
 186         if (!(buf = get_backup_name(fname)))
 187                 return 0;
 188
 189         /* Check to see if this is a device file, or link */
 190         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 191          || (preserve_specials && IS_SPECIAL(file->mode))) {
 192                 do_unlink(buf);
 193                 if (do_mknod(buf, file->mode, file->u.rdev) < 0
 194                     && (errno != ENOENT || make_bak_dir(buf) < 0
 195                      || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
 196                         rsyserr(FERROR, errno, "mknod %s failed",
 197                                 full_fname(buf));
 198                 } else if (verbose > 2) {
 199                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 200                                 fname);
 201                 }
 202                 kept = 1;
 203                 do_unlink(fname);
 204         }
 205
 206         if (!kept && S_ISDIR(file->mode)) {
 207                 /* make an empty directory */
 208                 if (do_mkdir(buf, file->mode) < 0
 209                     && (errno != ENOENT || make_bak_dir(buf) < 0
 210                      || do_mkdir(buf, file->mode) < 0)) {
 211                         rsyserr(FINFO, errno, "mkdir %s failed",
 212                                 full_fname(buf));
 213                 }
 214
 215                 ret_code = do_rmdir(fname);
 216                 if (verbose > 2) {
 217                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 218                                 full_fname(fname), ret_code);
 219                 }
 220                 kept = 1;
 221         }
 222
 223 #ifdef SUPPORT_LINKS
 224         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 225                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
 226                         if (verbose) {
 227                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 228                                         full_fname(buf), file->u.link);
 229                         }
 230                         kept = 1;
 231                 } else {
 232                         do_unlink(buf);
 233                         if (do_symlink(file->u.link, buf) < 0
 234                             && (errno != ENOENT || make_bak_dir(buf) < 0
 235                              || do_symlink(file->u.link, buf) < 0)) {
 236                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 237                                         full_fname(buf),
 238                                         file->u.link);
 239                         }
 240                         do_unlink(fname);
 241                         kept = 1;
 242                 }
 243         }
 244 #endif
 245
 246         if (!kept && !S_ISREG(file->mode)) {
 247                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 248                         fname);
 249                 return 1;
 250         }
 251
 252         /* move to keep tree if a file */
 253         if (!kept) {
 254                 if (robust_move(fname, buf) != 0) {
 255                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 256                                 full_fname(fname), buf);
 257                 } else if (st.st_nlink > 1) {
 258                         /* If someone has hard-linked the file into the backup
 259                          * dir, rename() might return success but do nothing! */
 260                         robust_unlink(fname); /* Just in case... */
 261                 }
 262         }
 263         set_file_attrs(buf, file, NULL, 0);
 264         free(file);
 265
 266         if (verbose > 1) {
 267                 rprintf(FINFO, "backed up %s to %s\n",
 268                         fname, buf);
 269         }
 270         return 1;
 271 }
 272
 273
 274 /* main backup switch routine */
 275 int make_backup(char *fname)
 276 {
 277         if (backup_dir)
 278                 return keep_backup(fname);
 279         return make_simple_backup(fname);
 280 }