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_specials;
  34 extern int preserve_links;
  35 extern int preserve_hard_links;
  36 extern int orig_umask;
  37 extern int safe_symlinks;
  38
  39 /* make a complete pathname for backup file */
  40 char *get_backup_name(char *fname)
  41 {
  42         if (backup_dir) {
  43                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  44                                fname, backup_suffix, NULL) < backup_dir_remainder)
  45                         return backup_dir_buf;
  46         } else {
  47                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  48                                fname, backup_suffix, NULL) < MAXPATHLEN)
  49                         return backup_dir_buf;
  50         }
  51
  52         rprintf(FERROR, "backup filename too long\n");
  53         return NULL;
  54 }
  55
  56 /* simple backup creates a backup with a suffix in the same directory */
  57 static int make_simple_backup(char *fname)
  58 {
  59         int rename_errno;
  60         char *fnamebak = get_backup_name(fname);
  61
  62         if (!fnamebak)
  63                 return 0;
  64
  65         while (1) {
  66                 if (do_rename(fname, fnamebak) == 0) {
  67                         if (verbose > 1) {
  68                                 rprintf(FINFO, "backed up %s to %s\n",
  69                                         fname, fnamebak);
  70                         }
  71                         break;
  72                 }
  73                 /* cygwin (at least version b19) reports EINVAL */
  74                 if (errno == ENOENT || errno == EINVAL)
  75                         break;
  76
  77                 rename_errno = errno;
  78                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  79                         continue;
  80                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  81                         continue;
  82
  83                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  84                         fname, fnamebak);
  85                 errno = rename_errno;
  86                 return 0;
  87         }
  88
  89         return 1;
  90 }
  91
  92
  93 /****************************************************************************
  94 Create a directory given an absolute path, perms based upon another directory
  95 path
  96 ****************************************************************************/
  97 static int make_bak_dir(char *fullpath)
  98 {
  99         STRUCT_STAT st;
 100         char *rel = fullpath + backup_dir_len;
 101         char *end = rel + strlen(rel);
 102         char *p = end;
 103
 104         while (strncmp(fullpath, "./", 2) == 0)
 105                 fullpath += 2;
 106
 107         /* Try to find an existing dir, starting from the deepest dir. */
 108         while (1) {
 109                 if (--p == fullpath) {
 110                         p += strlen(p);
 111                         goto failure;
 112                 }
 113                 if (*p == '/') {
 114                         *p = '\0';
 115                         if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
 116                                 break;
 117                         if (errno != ENOENT) {
 118                                 rsyserr(FERROR, errno,
 119                                         "make_bak_dir mkdir %s failed",
 120                                         full_fname(fullpath));
 121                                 goto failure;
 122                         }
 123                 }
 124         }
 125
 126         /* Make all the dirs that we didn't find on the way here. */
 127         while (1) {
 128                 if (p >= rel) {
 129                         /* Try to transfer the directory settings of the
 130                          * actual dir that the files are coming from. */
 131                         if (do_stat(rel, &st) < 0) {
 132                                 rsyserr(FERROR, errno,
 133                                         "make_bak_dir stat %s failed",
 134                                         full_fname(rel));
 135                         } else {
 136                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 137                                 do_chmod(fullpath, st.st_mode);
 138                         }
 139                 }
 140                 *p = '/';
 141                 p += strlen(p);
 142                 if (p == end)
 143                         break;
 144                 if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
 145                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 146                                 full_fname(fullpath));
 147                         goto failure;
 148                 }
 149         }
 150         return 0;
 151
 152   failure:
 153         while (p != end) {
 154                 *p = '/';
 155                 p += strlen(p);
 156         }
 157         return -1;
 158 }
 159
 160 /* robustly move a file, creating new directory structures if necessary */
 161 static int robust_move(char *src, char *dst)
 162 {
 163         if (robust_rename(src, dst, 0755) < 0 && (errno != ENOENT
 164             || make_bak_dir(dst) < 0 || robust_rename(src, dst, 0755) < 0))
 165                 return -1;
 166         return 0;
 167 }
 168
 169
 170 /* If we have a --backup-dir, then we get here from make_backup().
 171  * We will move the file to be deleted into a parallel directory tree. */
 172 static int keep_backup(char *fname)
 173 {
 174         STRUCT_STAT st;
 175         struct file_struct *file;
 176         char *buf;
 177         int kept = 0;
 178         int ret_code;
 179
 180         /* return if no file to keep */
 181         if (do_lstat(fname, &st) < 0)
 182                 return 1;
 183
 184         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 185                 return 1; /* the file could have disappeared */
 186
 187         if (!(buf = get_backup_name(fname)))
 188                 return 0;
 189
 190         /* Check to see if this is a device file, or link */
 191         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 192          || (preserve_specials && IS_SPECIAL(file->mode))) {
 193                 do_unlink(buf);
 194                 if (do_mknod(buf, file->mode, file->u.rdev) < 0
 195                     && (errno != ENOENT || make_bak_dir(buf) < 0
 196                      || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
 197                         rsyserr(FERROR, errno, "mknod %s failed",
 198                                 full_fname(buf));
 199                 } else if (verbose > 2) {
 200                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 201                                 fname);
 202                 }
 203                 kept = 1;
 204                 do_unlink(fname);
 205         }
 206
 207         if (!kept && S_ISDIR(file->mode)) {
 208                 /* make an empty directory */
 209                 if (do_mkdir(buf, file->mode) < 0
 210                     && (errno != ENOENT || make_bak_dir(buf) < 0
 211                      || do_mkdir(buf, file->mode) < 0)) {
 212                         rsyserr(FINFO, errno, "mkdir %s failed",
 213                                 full_fname(buf));
 214                 }
 215
 216                 ret_code = do_rmdir(fname);
 217                 if (verbose > 2) {
 218                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 219                                 full_fname(fname), ret_code);
 220                 }
 221                 kept = 1;
 222         }
 223
 224 #ifdef SUPPORT_LINKS
 225         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 226                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
 227                         if (verbose) {
 228                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 229                                         full_fname(buf), file->u.link);
 230                         }
 231                         kept = 1;
 232                 } else {
 233                         do_unlink(buf);
 234                         if (do_symlink(file->u.link, buf) < 0
 235                             && (errno != ENOENT || make_bak_dir(buf) < 0
 236                              || do_symlink(file->u.link, buf) < 0)) {
 237                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 238                                         full_fname(buf),
 239                                         file->u.link);
 240                         }
 241                         do_unlink(fname);
 242                         kept = 1;
 243                 }
 244         }
 245 #endif
 246
 247         if (!kept && !S_ISREG(file->mode)) {
 248                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 249                         fname);
 250                 return 1;
 251         }
 252
 253         /* move to keep tree if a file */
 254         if (!kept) {
 255                 if (robust_move(fname, buf) != 0) {
 256                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 257                                 full_fname(fname), buf);
 258                 } else if (st.st_nlink > 1) {
 259                         /* If someone has hard-linked the file into the backup
 260                          * dir, rename() might return success but do nothing! */
 261                         robust_unlink(fname); /* Just in case... */
 262                 }
 263         }
 264         set_perms(buf, file, NULL, 0);
 265         free(file);
 266
 267         if (verbose > 1) {
 268                 rprintf(FINFO, "backed up %s to %s\n",
 269                         fname, buf);
 270         }
 271         return 1;
 272 }
 273
 274
 275 /* main backup switch routine */
 276 int make_backup(char *fname)
 277 {
 278         if (backup_dir)
 279                 return keep_backup(fname);
 280         return make_simple_backup(fname);
 281 }