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 extern int safe_symlinks;
  37
  38 /* make a complete pathname for backup file */
  39 char *get_backup_name(char *fname)
  40 {
  41         if (backup_dir) {
  42                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  43                                fname, backup_suffix, NULL) < backup_dir_remainder)
  44                         return backup_dir_buf;
  45         } else {
  46                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  47                                fname, backup_suffix, NULL) < MAXPATHLEN)
  48                         return backup_dir_buf;
  49         }
  50
  51         rprintf(FERROR, "backup filename too long\n");
  52         return NULL;
  53 }
  54
  55 /* simple backup creates a backup with a suffix in the same directory */
  56 static int make_simple_backup(char *fname)
  57 {
  58         int rename_errno;
  59         char *fnamebak = get_backup_name(fname);
  60
  61         if (!fnamebak)
  62                 return 0;
  63
  64         while (1) {
  65                 if (do_rename(fname, fnamebak) == 0) {
  66                         if (verbose > 1) {
  67                                 rprintf(FINFO, "backed up %s to %s\n",
  68                                         fname, fnamebak);
  69                         }
  70                         break;
  71                 }
  72                 /* cygwin (at least version b19) reports EINVAL */
  73                 if (errno == ENOENT || errno == EINVAL)
  74                         break;
  75
  76                 rename_errno = errno;
  77                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  78                         continue;
  79                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  80                         continue;
  81
  82                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  83                         fname, fnamebak);
  84                 errno = rename_errno;
  85                 return 0;
  86         }
  87
  88         return 1;
  89 }
  90
  91
  92 /****************************************************************************
  93 Create a directory given an absolute path, perms based upon another directory
  94 path
  95 ****************************************************************************/
  96 static int make_bak_dir(char *fullpath)
  97 {
  98         STRUCT_STAT st;
  99         char *rel = fullpath + backup_dir_len;
 100         char *end = rel + strlen(rel);
 101         char *p = end;
 102
 103         while (strncmp(fullpath, "./", 2) == 0)
 104                 fullpath += 2;
 105
 106         /* Try to find an existing dir, starting from the deepest dir. */
 107         while (1) {
 108                 if (--p == fullpath) {
 109                         p += strlen(p);
 110                         goto failure;
 111                 }
 112                 if (*p == '/') {
 113                         *p = '\0';
 114                         if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
 115                                 break;
 116                         if (errno != ENOENT) {
 117                                 rsyserr(FERROR, errno,
 118                                         "make_bak_dir mkdir %s failed",
 119                                         full_fname(fullpath));
 120                                 goto failure;
 121                         }
 122                 }
 123         }
 124
 125         /* Make all the dirs that we didn't find on the way here. */
 126         while (1) {
 127                 if (p >= rel) {
 128                         /* Try to transfer the directory settings of the
 129                          * actual dir that the files are coming from. */
 130                         if (do_stat(rel, &st) < 0) {
 131                                 rsyserr(FERROR, errno,
 132                                         "make_bak_dir stat %s failed",
 133                                         full_fname(rel));
 134                         } else {
 135                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 136                                 do_chmod(fullpath, st.st_mode);
 137                         }
 138                 }
 139                 *p = '/';
 140                 p += strlen(p);
 141                 if (p == end)
 142                         break;
 143                 if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
 144                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 145                                 full_fname(fullpath));
 146                         goto failure;
 147                 }
 148         }
 149         return 0;
 150
 151   failure:
 152         while (p != end) {
 153                 *p = '/';
 154                 p += strlen(p);
 155         }
 156         return -1;
 157 }
 158
 159 /* robustly move a file, creating new directory structures if necessary */
 160 static int robust_move(char *src, char *dst)
 161 {
 162         if (robust_rename(src, dst, 0755) < 0 && (errno != ENOENT
 163             || make_bak_dir(dst) < 0 || robust_rename(src, dst, 0755) < 0))
 164                 return -1;
 165         return 0;
 166 }
 167
 168
 169 /* If we have a --backup-dir, then we get here from make_backup().
 170  * We will move the file to be deleted into a parallel directory tree. */
 171 static int keep_backup(char *fname)
 172 {
 173         STRUCT_STAT st;
 174         struct file_struct *file;
 175         char *buf;
 176         int kept = 0;
 177         int ret_code;
 178
 179         /* return if no file to keep */
 180         if (do_lstat(fname, &st) < 0)
 181                 return 1;
 182
 183         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 184                 return 1; /* the file could have disappeared */
 185
 186         if (!(buf = get_backup_name(fname)))
 187                 return 0;
 188
 189         /* Check to see if this is a device file, or link */
 190         if (IS_DEVICE(file->mode) && am_root && preserve_devices) {
 191                 do_unlink(buf);
 192                 if (do_mknod(buf, file->mode, file->u.rdev) < 0
 193                     && (errno != ENOENT || make_bak_dir(buf) < 0
 194                      || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
 195                         rsyserr(FERROR, errno, "mknod %s failed",
 196                                 full_fname(buf));
 197                 } else if (verbose > 2) {
 198                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 199                                 fname);
 200                 }
 201                 kept = 1;
 202                 do_unlink(fname);
 203         }
 204
 205         if (!kept && S_ISDIR(file->mode)) {
 206                 /* make an empty directory */
 207                 if (do_mkdir(buf, file->mode) < 0
 208                     && (errno != ENOENT || make_bak_dir(buf) < 0
 209                      || do_mkdir(buf, file->mode) < 0)) {
 210                         rsyserr(FINFO, errno, "mkdir %s failed",
 211                                 full_fname(buf));
 212                 }
 213
 214                 ret_code = do_rmdir(fname);
 215                 if (verbose > 2) {
 216                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 217                                 full_fname(fname), ret_code);
 218                 }
 219                 kept = 1;
 220         }
 221
 222 #ifdef SUPPORT_LINKS
 223         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 224                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
 225                         if (verbose) {
 226                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 227                                         full_fname(buf), file->u.link);
 228                         }
 229                         kept = 1;
 230                 } else {
 231                         do_unlink(buf);
 232                         if (do_symlink(file->u.link, buf) < 0
 233                             && (errno != ENOENT || make_bak_dir(buf) < 0
 234                              || do_symlink(file->u.link, buf) < 0)) {
 235                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 236                                         full_fname(buf),
 237                                         file->u.link);
 238                         }
 239                         do_unlink(fname);
 240                         kept = 1;
 241                 }
 242         }
 243 #endif
 244
 245         if (!kept && !S_ISREG(file->mode)) {
 246                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 247                         fname);
 248                 return 1;
 249         }
 250
 251         /* move to keep tree if a file */
 252         if (!kept) {
 253                 if (robust_move(fname, buf) != 0) {
 254                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 255                                 full_fname(fname), buf);
 256                 } else if (st.st_nlink > 1) {
 257                         /* If someone has hard-linked the file into the backup
 258                          * dir, rename() might return success but do nothing! */
 259                         robust_unlink(fname); /* Just in case... */
 260                 }
 261         }
 262         set_perms(buf, file, NULL, 0);
 263         free(file);
 264
 265         if (verbose > 1) {
 266                 rprintf(FINFO, "backed up %s to %s\n",
 267                         fname, buf);
 268         }
 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 }