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         return 1;
  77 } /* make_dir */
  78
  79
  80 /****************************************************************************
  81 Create a directory given an absolute path, perms based upon another directory
  82 path
  83 ****************************************************************************/
  84 static int make_bak_dir(char *fname, char *bak_path)
  85 {
  86         STRUCT_STAT st;
  87         STRUCT_STAT *st2;
  88         char fullpath[MAXPATHLEN];
  89         extern int orig_umask;
  90         char *p;
  91         char *q;
  92
  93         while(strncmp(bak_path, "./", 2) == 0) bak_path += 2;
  94
  95         if(bak_path[strlen(bak_path)-1] != '/') {
  96                 snprintf(fullpath, sizeof(fullpath), "%s/", bak_path);
  97         } else {
  98                 snprintf(fullpath, sizeof(fullpath), "%s", bak_path);
  99         }
 100         p = fullpath;
 101         q = &fullpath[strlen(fullpath)];  /* End of bak_path string */
 102         strcat(fullpath, fname);
 103
 104         /* Make the directories */
 105         while ((p = strchr(p, '/'))) {
 106                 *p = 0;
 107                 if(do_lstat(fullpath, &st) != 0) {
 108                         do_mkdir(fullpath, 0777 & ~orig_umask);
 109                         if(p>q) {
 110                                 if(do_lstat(q, &st) != 0) {
 111                                         rprintf(FERROR, "make_bak_dir stat %s failed: %s\n",
 112                                                 full_fname(fullpath), strerror(errno));
 113                                 } else {
 114                                         st2 = &st;
 115                                         set_modtime(fullpath, st2->st_mtime);
 116                                         if(do_lchown(fullpath, st2->st_uid, st2->st_gid) != 0) {
 117                                                 rprintf(FERROR, "make_bak_dir chown %s failed: %s\n",
 118                                                         full_fname(fullpath), strerror(errno));
 119                                         }
 120                                         if(do_chmod(fullpath, st2->st_mode) != 0) {
 121                                                 rprintf(FERROR, "make_bak_dir failed to set permissions on %s: %s\n",
 122                                                         full_fname(fullpath), strerror(errno));
 123                                         }
 124                                 }
 125                         }
 126                 }
 127                 *p = '/';
 128                 p++;
 129         }
 130         return 0;
 131 }
 132
 133 /* robustly move a file, creating new directory structures if necessary */
 134 static int robust_move(char *src, char *dst)
 135 {
 136         int keep_trying = 4;
 137         int keep_path_extfs = 0;
 138         int failed;
 139
 140         while (keep_trying) {
 141                 if (keep_path_extfs) {
 142                         failed = copy_file(src, dst, 0755);
 143                         if (!failed) {
 144                                 do_unlink(src);
 145                         }
 146                 } else {
 147                         failed = robust_rename (src, dst);
 148                 }
 149
 150                 if (failed) {
 151                         if (verbose > 2)
 152                                 rprintf (FERROR, "robust_move failed: %s(%d)\n",
 153                                     strerror (errno), errno);
 154                         switch (errno) {
 155                                 /* external filesystem */
 156                                 case EXDEV:
 157                                         keep_path_extfs = 1;
 158                                         keep_trying--;
 159                                         break;
 160                                 /* no directory to write to */
 161                                 case ENOENT:
 162                                         make_dir(dst, 0700);
 163                                         keep_trying--;
 164                                         break;
 165                                 default:
 166                                         keep_trying = 0;
 167                         } /* switch */
 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
 180         static int initialised;
 181
 182         char keep_name [MAXPATHLEN];
 183         STRUCT_STAT st;
 184         struct file_struct *file;
 185
 186         int kept = 0;
 187         int ret_code;
 188
 189         if (!initialised) {
 190                 if (backup_dir_len && backup_dir[backup_dir_len - 1] == '/')
 191                         backup_dir[--backup_dir_len] = '\0';
 192                 if (verbose > 0)
 193                         rprintf (FINFO, "backup_dir is %s\n", backup_dir);
 194                 initialised = 1;
 195         }
 196
 197         /* return if no file to keep */
 198 #if SUPPORT_LINKS
 199         if (do_lstat (fname, &st)) return 1;
 200 #else
 201         if (do_stat (fname, &st)) return 1;
 202 #endif
 203
 204         file = make_file(fname, NULL, NO_EXCLUDES);
 205
 206         /* the file could have disappeared */
 207         if (!file) return 1;
 208
 209         /* make a complete pathname for backup file */
 210         if (backup_dir_len+strlen(fname)+backup_suffix_len > MAXPATHLEN-1) {
 211                 rprintf (FERROR, "keep_backup filename too long\n");
 212                 return 0;
 213         }
 214
 215         snprintf(keep_name, sizeof (keep_name), "%s/%s%s",
 216             backup_dir, fname, backup_suffix);
 217
 218 #ifdef HAVE_MKNOD
 219         /* Check to see if this is a device file, or link */
 220         if(IS_DEVICE(file->mode)) {
 221                 if(am_root && preserve_devices) {
 222                         make_bak_dir(fname, backup_dir);
 223                         if(do_mknod(keep_name, file->mode, file->rdev) != 0) {
 224                                 rprintf(FERROR, "mknod %s failed: %s\n",
 225                                         full_fname(keep_name), strerror(errno));
 226                         } else if(verbose>2) {
 227                                 rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
 228                         }
 229                 }
 230                 kept = 1;
 231                 do_unlink(fname);
 232         }
 233 #endif
 234
 235         if(!kept && S_ISDIR(file->mode)) {
 236                 /* make an empty directory */
 237                 make_bak_dir(fname, backup_dir);
 238                 do_mkdir(keep_name, file->mode);
 239                 ret_code = do_rmdir(fname);
 240
 241                 if(verbose>2) {
 242                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 243                                 full_fname(fname), ret_code);
 244                 }
 245                 kept = 1;
 246         }
 247
 248 #if SUPPORT_LINKS
 249         if(!kept && preserve_links && S_ISLNK(file->mode)) {
 250                 extern int safe_symlinks;
 251                 if (safe_symlinks && unsafe_symlink(file->link, keep_name)) {
 252                         if (verbose) {
 253                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 254                                         full_fname(keep_name), file->link);
 255                         }
 256                         kept = 1;
 257                 }
 258                 make_bak_dir(fname, backup_dir);
 259                 if(do_symlink(file->link, keep_name) != 0) {
 260                         rprintf(FERROR, "link %s -> %s : %s\n",
 261                                 full_fname(keep_name), file->link, strerror(errno));
 262                 }
 263                 do_unlink(fname);
 264                 kept = 1;
 265         }
 266 #endif
 267         if(!kept && preserve_hard_links && check_hard_link(file)) {
 268                 if(verbose > 1)
 269                         rprintf(FINFO, "%s is a hard link\n", f_name(file));
 270         }
 271
 272         if(!kept && !S_ISREG(file->mode)) {
 273                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 274                     fname);
 275         }
 276
 277         /* move to keep tree if a file */
 278         if(!kept) {
 279                 if (!robust_move (fname, keep_name)) {
 280                         rprintf(FERROR, "keep_backup failed: %s -> \"%s\": %s\n",
 281                                 full_fname(fname), keep_name, strerror(errno));
 282                 }
 283         }
 284         set_perms (keep_name, file, NULL, 0);
 285         free_file (file);
 286         free (file);
 287
 288         if (verbose > 1)
 289                 rprintf (FINFO, "keep_backup %s -> %s\n", fname, keep_name);
 290         return 1;
 291 } /* keep_backup */
 292
 293
 294 /* main backup switch routine */
 295 int make_backup(char *fname)
 296 {
 297         if (backup_dir)
 298                 return (keep_backup(fname));
 299         else
 300                 return (make_simple_backup(fname));
 301 }