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 : %s\n", fullpath, strerror(errno));
 112                                 } else {
 113                                         st2 = &st;
 114                                         set_modtime(fullpath, st2->st_mtime);
 115                                         if(do_lchown(fullpath, st2->st_uid, st2->st_gid) != 0) {
 116                                                 rprintf(FERROR, "make_bak_dir chown %s : %s\n", fullpath, strerror(errno));
 117                                         }
 118                                         if(do_chmod(fullpath, st2->st_mode) != 0) {
 119                                                 rprintf(FERROR, "make_bak_dir failed to set permissions on %s : %s\n", fullpath, strerror(errno));
 120                                         }
 121                                 }
 122                         }
 123                 }
 124                 *p = '/';
 125                 p++;
 126         }
 127         return 0;
 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                         }
 143                 } else {
 144                         failed = robust_rename (src, dst);
 145                 }
 146
 147                 if (failed) {
 148                         if (verbose > 2)
 149                                 rprintf (FERROR, "robust_move failed: %s(%d)\n",
 150                                     strerror (errno), errno);
 151                         switch (errno) {
 152                                 /* external filesystem */
 153                                 case EXDEV:
 154                                         keep_path_extfs = 1;
 155                                         keep_trying--;
 156                                         break;
 157                                 /* no directory to write to */
 158                                 case ENOENT:
 159                                         make_dir (dst, 0755);
 160                                         keep_trying--;
 161                                         break;
 162                                 default:
 163                                         keep_trying = 0;
 164                         } /* switch */
 165                 } else
 166                         keep_trying = 0;
 167         } /* while */
 168         return (!failed);
 169 } /* robust_move */
 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
 177         static int initialised;
 178
 179         char keep_name [MAXPATHLEN];
 180         STRUCT_STAT st;
 181         struct file_struct *file;
 182
 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 (backup_dir_len+strlen(fname)+backup_suffix_len > MAXPATHLEN-1) {
 208                 rprintf (FERROR, "keep_backup filename too long\n");
 209                 return 0;
 210         }
 211
 212         snprintf(keep_name, sizeof (keep_name), "%s/%s%s",
 213             backup_dir, fname, backup_suffix);
 214
 215 #ifdef HAVE_MKNOD
 216         /* Check to see if this is a device file, or link */
 217         if(IS_DEVICE(file->mode)) {
 218                 if(am_root && preserve_devices) {
 219                         make_bak_dir(fname, backup_dir);
 220                         if(do_mknod(keep_name, file->mode, file->rdev) != 0) {
 221                                 rprintf(FERROR, "mknod %s : %s\n",
 222                                     keep_name, strerror(errno));
 223                         } else if(verbose>2) {
 224                                 rprintf(FINFO, "make_backup : DEVICE %s successful.\n", fname);
 225                         }
 226                 }
 227                 kept = 1;
 228                 do_unlink(fname);
 229         }
 230 #endif
 231
 232         if(!kept && S_ISDIR(file->mode)) {
 233                 /* make an empty directory */
 234                 make_bak_dir(fname, backup_dir);
 235                 do_mkdir(keep_name, file->mode);
 236                 ret_code = do_rmdir(fname);
 237
 238                 if(verbose>2) {
 239                         rprintf(FINFO, "make_backup : RMDIR %s returns %i\n",
 240                             fname, ret_code);
 241                 }
 242                 kept = 1;
 243         }
 244
 245 #if SUPPORT_LINKS
 246         if(!kept && preserve_links && S_ISLNK(file->mode)) {
 247                 extern int safe_symlinks;
 248                 if (safe_symlinks && unsafe_symlink(file->link, keep_name)) {
 249                         if (verbose) {
 250                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 251                                         keep_name, file->link);
 252                         }
 253                         kept = 1;
 254                 }
 255                 make_bak_dir(fname, backup_dir);
 256                 if(do_symlink(file->link, keep_name) != 0) {
 257                         rprintf(FERROR, "link %s -> %s : %s\n",
 258                             keep_name, file->link, strerror(errno));
 259                 }
 260                 do_unlink(fname);
 261                 kept = 1;
 262         }
 263 #endif
 264         if(!kept && preserve_hard_links && check_hard_link(file)) {
 265                 if(verbose > 1)
 266                         rprintf(FINFO, "%s is a hard link\n", f_name(file));
 267         }
 268
 269         if(!kept && !S_ISREG(file->mode)) {
 270                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 271                     fname);
 272         }
 273
 274         /* move to keep tree if a file */
 275         if(!kept) {
 276                 if (!robust_move (fname, keep_name)) {
 277                         rprintf(FERROR, "keep_backup failed %s -> %s : %s\n",
 278                             fname, keep_name, strerror(errno));
 279                 }
 280         }
 281         set_perms (keep_name, file, NULL, 0);
 282         free_file (file);
 283         free (file);
 284
 285         if (verbose > 1)
 286                 rprintf (FINFO, "keep_backup %s -> %s\n", fname, keep_name);
 287         return 1;
 288 } /* keep_backup */
 289
 290
 291 /* main backup switch routine */
 292 int make_backup(char *fname)
 293 {
 294         if (backup_dir)
 295                 return (keep_backup(fname));
 296         else
 297                 return (make_simple_backup(fname));
 298 }