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_suffix_len;
  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_links;
  34 extern int preserve_hard_links;
  35 extern int orig_umask;
  36
  37 /* simple backup creates a backup with a suffix in the same directory */
  38 static int make_simple_backup(char *fname)
  39 {
  40         char fnamebak[MAXPATHLEN];
  41
  42         if (stringjoin(fnamebak, sizeof fnamebak, fname, backup_suffix, NULL)
  43             >= sizeof fnamebak) {
  44                 rprintf(FERROR, "backup filename too long\n");
  45                 return 0;
  46         }
  47
  48         if (do_rename(fname, fnamebak) != 0) {
  49                 /* cygwin (at least version b19) reports EINVAL */
  50                 if (errno != ENOENT && errno != EINVAL) {
  51                         rsyserr(FERROR, errno, "rename %s to backup %s", fname, fnamebak);
  52                         return 0;
  53                 }
  54         } else if (verbose > 1) {
  55                 rprintf(FINFO, "backed up %s to %s\n", fname, fnamebak);
  56         }
  57         return 1;
  58 }
  59
  60
  61 /****************************************************************************
  62 Create a directory given an absolute path, perms based upon another directory
  63 path
  64 ****************************************************************************/
  65 static int make_bak_dir(char *fullpath)
  66 {
  67         STRUCT_STAT st;
  68         char *rel = fullpath + backup_dir_len;
  69         char *end = rel + strlen(rel);
  70         char *p = end;
  71
  72         while (strncmp(fullpath, "./", 2) == 0)
  73                 fullpath += 2;
  74
  75         /* Try to find an existing dir, starting from the deepest dir. */
  76         while (1) {
  77                 if (--p == fullpath) {
  78                         p += strlen(p);
  79                         goto failure;
  80                 }
  81                 if (*p == '/') {
  82                         *p = '\0';
  83                         if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
  84                                 break;
  85                         if (errno != ENOENT) {
  86                                 rprintf(FERROR,
  87                                     "make_bak_dir mkdir %s failed: %s\n",
  88                                     full_fname(fullpath), strerror(errno));
  89                                 goto failure;
  90                         }
  91                 }
  92         }
  93
  94         /* Make all the dirs that we didn't find on the way here. */
  95         while (1) {
  96                 if (p >= rel) {
  97                         /* Try to transfer the directory settings of the
  98                          * actual dir that the files are coming from. */
  99                         if (do_lstat(rel, &st) != 0) {
 100                                 rprintf(FERROR,
 101                                     "make_bak_dir stat %s failed: %s\n",
 102                                     full_fname(rel), strerror(errno));
 103                         } else {
 104                                 set_modtime(fullpath, st.st_mtime);
 105                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 106                                 do_chmod(fullpath, st.st_mode);
 107                         }
 108                 }
 109                 *p = '/';
 110                 p += strlen(p);
 111                 if (p == end)
 112                         break;
 113                 if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
 114                         rprintf(FERROR,
 115                             "make_bak_dir mkdir %s failed: %s\n",
 116                             full_fname(fullpath), strerror(errno));
 117                         goto failure;
 118                 }
 119         }
 120         return 0;
 121
 122 failure:
 123         while (p != end) {
 124                 *p = '/';
 125                 p += strlen(p);
 126         }
 127         return -1;
 128 }
 129
 130 /* robustly move a file, creating new directory structures if necessary */
 131 static int robust_move(char *src, char *dst)
 132 {
 133         int keep_trying = 4;
 134         int keep_path_extfs = 0;
 135         int failed;
 136
 137         while (keep_trying) {
 138                 if (keep_path_extfs) {
 139                         failed = copy_file(src, dst, 0755);
 140                         if (!failed)
 141                                 do_unlink(src);
 142                 } else
 143                         failed = robust_rename(src, dst);
 144
 145                 if (failed) {
 146                         if (verbose > 2) {
 147                                 rprintf(FERROR, "robust_move failed: %s(%d)\n",
 148                                         strerror(errno), errno);
 149                         }
 150                         switch (errno) {
 151                         case EXDEV:     /* external filesystem */
 152                                 keep_path_extfs = 1;
 153                                 keep_trying--;
 154                                 break;
 155                         case ENOENT:    /* no directory to write to */
 156                                 if (make_bak_dir(dst) < 0)
 157                                         keep_trying = 0;
 158                                 else
 159                                         keep_trying--;
 160                                 break;
 161                         default:
 162                                 keep_trying = 0;
 163                                 break;
 164                         }
 165                 } else
 166                         keep_trying = 0;
 167         }
 168         return !failed;
 169 }
 170
 171
 172 /* If we have a --backup-dir, then we get here from make_backup().
 173  * We will move the file to be deleted into a parallel directory tree. */
 174 static int keep_backup(char *fname)
 175 {
 176         STRUCT_STAT st;
 177         struct file_struct *file;
 178         int kept = 0;
 179         int ret_code;
 180
 181         /* return if no file to keep */
 182 #if SUPPORT_LINKS
 183         if (do_lstat(fname, &st)) return 1;
 184 #else
 185         if (do_stat(fname, &st)) return 1;
 186 #endif
 187
 188         file = make_file(fname, NULL, NO_EXCLUDES);
 189
 190         /* the file could have disappeared */
 191         if (!file) return 1;
 192
 193         /* make a complete pathname for backup file */
 194         if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
 195             fname, backup_suffix, NULL) >= backup_dir_remainder) {
 196                 rprintf(FERROR, "keep_backup filename too long\n");
 197                 return 0;
 198         }
 199
 200 #ifdef HAVE_MKNOD
 201         /* Check to see if this is a device file, or link */
 202         if (IS_DEVICE(file->mode)) {
 203                 if (am_root && preserve_devices) {
 204                         make_bak_dir(backup_dir_buf);
 205                         if (do_mknod(backup_dir_buf, file->mode, file->u.rdev) != 0) {
 206                                 rprintf(FERROR, "mknod %s failed: %s\n",
 207                                         full_fname(backup_dir_buf), strerror(errno));
 208                         } else if (verbose > 2) {
 209                                 rprintf(FINFO,
 210                                         "make_backup: DEVICE %s successful.\n",
 211                                         fname);
 212                         }
 213                 }
 214                 kept = 1;
 215                 do_unlink(fname);
 216         }
 217 #endif
 218
 219         if (!kept && S_ISDIR(file->mode)) {
 220                 /* make an empty directory */
 221                 make_bak_dir(backup_dir_buf);
 222                 do_mkdir(backup_dir_buf, file->mode);
 223                 ret_code = do_rmdir(fname);
 224
 225                 if (verbose > 2) {
 226                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 227                                 full_fname(fname), ret_code);
 228                 }
 229                 kept = 1;
 230         }
 231
 232 #if SUPPORT_LINKS
 233         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 234                 extern int safe_symlinks;
 235                 if (safe_symlinks && unsafe_symlink(file->u.link, backup_dir_buf)) {
 236                         if (verbose) {
 237                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 238                                         full_fname(backup_dir_buf), file->u.link);
 239                         }
 240                         kept = 1;
 241                 }
 242                 make_bak_dir(backup_dir_buf);
 243                 if (do_symlink(file->u.link, backup_dir_buf) != 0) {
 244                         rprintf(FERROR, "link %s -> %s : %s\n",
 245                                 full_fname(backup_dir_buf), file->u.link, strerror(errno));
 246                 }
 247                 do_unlink(fname);
 248                 kept = 1;
 249         }
 250 #endif
 251
 252         if (!kept && !S_ISREG(file->mode)) {
 253                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 254                         fname);
 255         }
 256
 257         /* move to keep tree if a file */
 258         if (!kept) {
 259                 if (!robust_move(fname, backup_dir_buf)) {
 260                         rprintf(FERROR, "keep_backup failed: %s -> \"%s\": %s\n",
 261                                 full_fname(fname), backup_dir_buf, strerror(errno));
 262                 }
 263         }
 264         set_perms(backup_dir_buf, file, NULL, 0);
 265         free(file);
 266
 267         if (verbose > 1)
 268                 rprintf(FINFO, "keep_backup %s -> %s\n", fname, backup_dir_buf);
 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 }