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