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 char *backup_suffix;
  27 extern char *backup_dir;
  28
  29 extern int am_root;
  30 extern int preserve_devices;
  31 extern int preserve_links;
  32 extern int preserve_hard_links;
  33
  34 /* simple backup creates a backup with a suffix in the same directory */
  35 static int make_simple_backup(char *fname)
  36 {
  37         char fnamebak[MAXPATHLEN];
  38         if (strlen(fname) + backup_suffix_len > MAXPATHLEN-1) {
  39                 rprintf(FERROR, "backup filename too long\n");
  40                 return 0;
  41         }
  42
  43         snprintf(fnamebak, sizeof(fnamebak), "%s%s", fname, backup_suffix);
  44         if (do_rename(fname, fnamebak) != 0) {
  45                 /* cygwin (at least version b19) reports EINVAL */
  46                 if (errno != ENOENT && errno != EINVAL) {
  47                         rsyserr(FERROR, errno, "rename %s to backup %s", fname, fnamebak);
  48                         return 0;
  49                 }
  50         } else if (verbose > 1) {
  51                 rprintf(FINFO, "backed up %s to %s\n", fname, fnamebak);
  52         }
  53         return 1;
  54 }
  55
  56
  57 /* recursively make a directory path */
  58 static int make_dir(char *name, int mask)
  59 {
  60         char newdir [MAXPATHLEN];
  61         char *p, *d;
  62
  63         /* copy pathname over, look for last '/' */
  64         for (p = d = newdir; *name; *d++ = *name++)
  65                 if (*name == '/')
  66                         p = d;
  67         if (p == newdir)
  68                 return 0;
  69         *p = 0;
  70
  71         /* make the new directory, if that fails then make its parent */
  72         while (do_mkdir(newdir, mask) != 0) {
  73                 if (errno != ENOENT || !make_dir(newdir, mask))
  74                         return 0;
  75         }
  76
  77         return 1;
  78 } /* make_dir */
  79
  80
  81 /****************************************************************************
  82 Create a directory given an absolute path, perms based upon another directory
  83 path
  84 ****************************************************************************/
  85 static int make_bak_dir(char *fname, char *bak_path)
  86 {
  87         STRUCT_STAT st;
  88         STRUCT_STAT *st2;
  89         char fullpath[MAXPATHLEN];
  90         extern int orig_umask;
  91         char *p;
  92         char *q;
  93
  94         while(strncmp(bak_path, "./", 2) == 0) bak_path += 2;
  95
  96         if (bak_path[strlen(bak_path)-1] != '/') {
  97                 snprintf(fullpath, sizeof(fullpath), "%s/", bak_path);
  98         } else {
  99                 snprintf(fullpath, sizeof(fullpath), "%s", bak_path);
 100         }
 101         p = fullpath;
 102         q = &fullpath[strlen(fullpath)];  /* End of bak_path string */
 103         strcat(fullpath, fname);
 104
 105         /* Make the directories */
 106         while ((p = strchr(p, '/')) != NULL) {
 107                 *p = 0;
 108                 if (do_lstat(fullpath, &st) != 0) {
 109                         do_mkdir(fullpath, 0777 & ~orig_umask);
 110                         if (p > q) {
 111                                 if (do_lstat(q, &st) != 0) {
 112                                         rprintf(FERROR, "make_bak_dir stat %s failed: %s\n",
 113                                                 full_fname(fullpath), strerror(errno));
 114                                 } else {
 115                                         st2 = &st;
 116                                         set_modtime(fullpath, st2->st_mtime);
 117                                         if (do_lchown(fullpath, st2->st_uid, st2->st_gid) != 0) {
 118                                                 rprintf(FERROR, "make_bak_dir chown %s failed: %s\n",
 119                                                         full_fname(fullpath), strerror(errno));
 120                                         }
 121                                         if (do_chmod(fullpath, st2->st_mode) != 0) {
 122                                                 rprintf(FERROR, "make_bak_dir failed to set permissions on %s: %s\n",
 123                                                         full_fname(fullpath), strerror(errno));
 124                                         }
 125                                 }
 126                         }
 127                 }
 128                 *p = '/';
 129                 p++;
 130         }
 131         return 0;
 132 }
 133
 134 /* robustly move a file, creating new directory structures if necessary */
 135 static int robust_move(char *src, char *dst)
 136 {
 137         int keep_trying = 4;
 138         int keep_path_extfs = 0;
 139         int failed;
 140
 141         while (keep_trying) {
 142                 if (keep_path_extfs) {
 143                         failed = copy_file(src, dst, 0755);
 144                         if (!failed)
 145                                 do_unlink(src);
 146                 } else
 147                         failed = robust_rename(src, dst);
 148
 149                 if (failed) {
 150                         if (verbose > 2) {
 151                                 rprintf(FERROR, "robust_move failed: %s(%d)\n",
 152                                         strerror(errno), errno);
 153                         }
 154                         switch (errno) {
 155                         case EXDEV:     /* external filesystem */
 156                                 keep_path_extfs = 1;
 157                                 keep_trying--;
 158                                 break;
 159                         case ENOENT:    /* no directory to write to */
 160                                 make_dir(dst, 0700);
 161                                 keep_trying--;
 162                                 break;
 163                         default:
 164                                 keep_trying = 0;
 165                                 break;
 166                         }
 167                 } else
 168                         keep_trying = 0;
 169         } /* while */
 170         return !failed;
 171 } /* robust_move */
 172
 173
 174 /* if we have a backup_dir, then we get here from make_backup().
 175    We will move the file to be deleted into a parallel directory tree */
 176 static int keep_backup(char *fname)
 177 {
 178
 179         static int initialised;
 180
 181         char keep_name [MAXPATHLEN];
 182         STRUCT_STAT st;
 183         struct file_struct *file;
 184
 185         int kept = 0;
 186         int ret_code;
 187
 188         if (!initialised) {
 189                 if (backup_dir_len && backup_dir[backup_dir_len - 1] == '/')
 190                         backup_dir[--backup_dir_len] = '\0';
 191                 if (verbose > 0)
 192                         rprintf(FINFO, "backup_dir is %s\n", backup_dir);
 193                 initialised = 1;
 194         }
 195
 196         /* return if no file to keep */
 197 #if SUPPORT_LINKS
 198         if (do_lstat(fname, &st)) return 1;
 199 #else
 200         if (do_stat(fname, &st)) return 1;
 201 #endif
 202
 203         file = make_file(fname, NULL, NO_EXCLUDES);
 204
 205         /* the file could have disappeared */
 206         if (!file) return 1;
 207
 208         /* make a complete pathname for backup file */
 209         if (backup_dir_len+strlen(fname)+backup_suffix_len > MAXPATHLEN-1) {
 210                 rprintf(FERROR, "keep_backup filename too long\n");
 211                 return 0;
 212         }
 213
 214         snprintf(keep_name, sizeof (keep_name), "%s/%s%s",
 215             backup_dir, fname, backup_suffix);
 216
 217 #ifdef HAVE_MKNOD
 218         /* Check to see if this is a device file, or link */
 219         if (IS_DEVICE(file->mode)) {
 220                 if (am_root && preserve_devices) {
 221                         make_bak_dir(fname, backup_dir);
 222                         if (do_mknod(keep_name, file->mode, file->u.rdev) != 0) {
 223                                 rprintf(FERROR, "mknod %s failed: %s\n",
 224                                         full_fname(keep_name), strerror(errno));
 225                         } else if (verbose > 2) {
 226                                 rprintf(FINFO,
 227                                         "make_backup: DEVICE %s successful.\n",
 228                                         fname);
 229                         }
 230                 }
 231                 kept = 1;
 232                 do_unlink(fname);
 233         }
 234 #endif
 235
 236         if (!kept && S_ISDIR(file->mode)) {
 237                 /* make an empty directory */
 238                 make_bak_dir(fname, backup_dir);
 239                 do_mkdir(keep_name, file->mode);
 240                 ret_code = do_rmdir(fname);
 241
 242                 if (verbose > 2) {
 243                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 244                                 full_fname(fname), ret_code);
 245                 }
 246                 kept = 1;
 247         }
 248
 249 #if SUPPORT_LINKS
 250         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 251                 extern int safe_symlinks;
 252                 if (safe_symlinks && unsafe_symlink(file->u.link, keep_name)) {
 253                         if (verbose) {
 254                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 255                                         full_fname(keep_name), file->u.link);
 256                         }
 257                         kept = 1;
 258                 }
 259                 make_bak_dir(fname, backup_dir);
 260                 if (do_symlink(file->u.link, keep_name) != 0) {
 261                         rprintf(FERROR, "link %s -> %s : %s\n",
 262                                 full_fname(keep_name), file->u.link, strerror(errno));
 263                 }
 264                 do_unlink(fname);
 265                 kept = 1;
 266         }
 267 #endif
 268         if (!kept && preserve_hard_links && file->link_u.links
 269             && file->F_HEAD != file) {
 270                 if (verbose > 1)
 271                         rprintf(FINFO, "%s is a hard link\n", f_name(file));
 272         }
 273
 274         if (!kept && !S_ISREG(file->mode)) {
 275                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 276                         fname);
 277         }
 278
 279         /* move to keep tree if a file */
 280         if (!kept) {
 281                 if (!robust_move(fname, keep_name)) {
 282                         rprintf(FERROR, "keep_backup failed: %s -> \"%s\": %s\n",
 283                                 full_fname(fname), keep_name, strerror(errno));
 284                 }
 285         }
 286         set_perms(keep_name, file, NULL, 0);
 287         free_file(file);
 288         free(file);
 289
 290         if (verbose > 1)
 291                 rprintf(FINFO, "keep_backup %s -> %s\n", fname, keep_name);
 292         return 1;
 293 } /* keep_backup */
 294
 295
 296 /* main backup switch routine */
 297 int make_backup(char *fname)
 298 {
 299         if (backup_dir)
 300                 return keep_backup(fname);
 301         return make_simple_backup(fname);
 302 }