backup.c

   1 /*
   2  * Backup handling code.
   3  *
   4  * Copyright (C) 1999 Andrew Tridgell
   5  * Copyright (C) 2003-2008 Wayne Davison
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, visit the http://fsf.org website.
  19  */
  20
  21 #include "rsync.h"
  22
  23 extern int verbose;
  24 extern int am_root;
  25 extern int preserve_acls;
  26 extern int preserve_xattrs;
  27 extern int preserve_devices;
  28 extern int preserve_specials;
  29 extern int preserve_links;
  30 extern int safe_symlinks;
  31 extern int backup_dir_len;
  32 extern unsigned int backup_dir_remainder;
  33 extern char backup_dir_buf[MAXPATHLEN];
  34 extern char *backup_suffix;
  35 extern char *backup_dir;
  36
  37 /* make a complete pathname for backup file */
  38 char *get_backup_name(const char *fname)
  39 {
  40         if (backup_dir) {
  41                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  42                                fname, backup_suffix, NULL) < backup_dir_remainder)
  43                         return backup_dir_buf;
  44         } else {
  45                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  46                                fname, backup_suffix, NULL) < MAXPATHLEN)
  47                         return backup_dir_buf;
  48         }
  49
  50         rprintf(FERROR, "backup filename too long\n");
  51         return NULL;
  52 }
  53
  54 /* simple backup creates a backup with a suffix in the same directory */
  55 static int make_simple_backup(const char *fname)
  56 {
  57         int rename_errno;
  58         const char *fnamebak = get_backup_name(fname);
  59
  60         if (!fnamebak)
  61                 return 0;
  62
  63         while (1) {
  64                 if (do_rename(fname, fnamebak) == 0) {
  65                         if (verbose > 1) {
  66                                 rprintf(FINFO, "backed up %s to %s\n",
  67                                         fname, fnamebak);
  68                         }
  69                         break;
  70                 }
  71                 /* cygwin (at least version b19) reports EINVAL */
  72                 if (errno == ENOENT || errno == EINVAL)
  73                         break;
  74
  75                 rename_errno = errno;
  76                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  77                         continue;
  78                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  79                         continue;
  80
  81                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  82                         fname, fnamebak);
  83                 errno = rename_errno;
  84                 return 0;
  85         }
  86
  87         return 1;
  88 }
  89
  90
  91 /****************************************************************************
  92 Create a directory given an absolute path, perms based upon another directory
  93 path
  94 ****************************************************************************/
  95 int make_bak_dir(const char *fullpath)
  96 {
  97         char fbuf[MAXPATHLEN], *rel, *end, *p;
  98         struct file_struct *file;
  99         int len = backup_dir_len;
 100         stat_x sx;
 101
 102         while (*fullpath == '.' && fullpath[1] == '/') {
 103                 fullpath += 2;
 104                 len -= 2;
 105         }
 106
 107         if (strlcpy(fbuf, fullpath, sizeof fbuf) >= sizeof fbuf)
 108                 return -1;
 109
 110         rel = fbuf + len;
 111         end = p = rel + strlen(rel);
 112
 113         /* Try to find an existing dir, starting from the deepest dir. */
 114         while (1) {
 115                 if (--p == fbuf)
 116                         return -1;
 117                 if (*p == '/') {
 118                         *p = '\0';
 119                         if (mkdir_defmode(fbuf) == 0)
 120                                 break;
 121                         if (errno != ENOENT) {
 122                                 rsyserr(FERROR, errno,
 123                                         "make_bak_dir mkdir %s failed",
 124                                         full_fname(fbuf));
 125                                 return -1;
 126                         }
 127                 }
 128         }
 129
 130         /* Make all the dirs that we didn't find on the way here. */
 131         while (1) {
 132                 if (p >= rel) {
 133                         /* Try to transfer the directory settings of the
 134                          * actual dir that the files are coming from. */
 135                         if (x_stat(rel, &sx.st, NULL) < 0) {
 136                                 rsyserr(FERROR, errno,
 137                                         "make_bak_dir stat %s failed",
 138                                         full_fname(rel));
 139                         } else {
 140 #ifdef SUPPORT_ACLS
 141                                 sx.acc_acl = sx.def_acl = NULL;
 142 #endif
 143 #ifdef SUPPORT_XATTRS
 144                                 sx.xattr = NULL;
 145 #endif
 146                                 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
 147                                         continue;
 148 #ifdef SUPPORT_ACLS
 149                                 if (preserve_acls && !S_ISLNK(file->mode)) {
 150                                         get_acl(rel, &sx);
 151                                         cache_acl(file, &sx);
 152                                         free_acl(&sx);
 153                                 }
 154 #endif
 155 #ifdef SUPPORT_XATTRS
 156                                 if (preserve_xattrs) {
 157                                         get_xattr(rel, &sx);
 158                                         cache_xattr(file, &sx);
 159                                         free_xattr(&sx);
 160                                 }
 161 #endif
 162                                 set_file_attrs(fbuf, file, NULL, NULL, 0);
 163                                 unmake_file(file);
 164                         }
 165                 }
 166                 *p = '/';
 167                 p += strlen(p);
 168                 if (p == end)
 169                         break;
 170                 if (mkdir_defmode(fbuf) < 0) {
 171                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 172                                 full_fname(fbuf));
 173                         return -1;
 174                 }
 175         }
 176
 177         return 0;
 178 }
 179
 180 /* robustly move a file, creating new directory structures if necessary */
 181 static int robust_move(const char *src, char *dst)
 182 {
 183         if (robust_rename(src, dst, NULL, 0755) < 0) {
 184                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 185                 if (errno == ENOENT && make_bak_dir(dst) == 0) {
 186                         if (robust_rename(src, dst, NULL, 0755) < 0)
 187                                 save_errno = errno ? errno : save_errno;
 188                         else
 189                                 save_errno = 0;
 190                 }
 191                 if (save_errno) {
 192                         errno = save_errno;
 193                         return -1;
 194                 }
 195         }
 196         return 0;
 197 }
 198
 199
 200 /* If we have a --backup-dir, then we get here from make_backup().
 201  * We will move the file to be deleted into a parallel directory tree. */
 202 static int keep_backup(const char *fname)
 203 {
 204         stat_x sx;
 205         struct file_struct *file;
 206         char *buf;
 207         int save_preserve_xattrs = preserve_xattrs;
 208         int kept = 0;
 209         int ret_code;
 210
 211         /* return if no file to keep */
 212         if (x_lstat(fname, &sx.st, NULL) < 0)
 213                 return 1;
 214 #ifdef SUPPORT_ACLS
 215         sx.acc_acl = sx.def_acl = NULL;
 216 #endif
 217 #ifdef SUPPORT_XATTRS
 218         sx.xattr = NULL;
 219 #endif
 220
 221         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 222                 return 1; /* the file could have disappeared */
 223
 224         if (!(buf = get_backup_name(fname))) {
 225                 unmake_file(file);
 226                 return 0;
 227         }
 228
 229 #ifdef SUPPORT_ACLS
 230         if (preserve_acls && !S_ISLNK(file->mode)) {
 231                 get_acl(fname, &sx);
 232                 cache_acl(file, &sx);
 233                 free_acl(&sx);
 234         }
 235 #endif
 236 #ifdef SUPPORT_XATTRS
 237         if (preserve_xattrs) {
 238                 get_xattr(fname, &sx);
 239                 cache_xattr(file, &sx);
 240                 free_xattr(&sx);
 241         }
 242 #endif
 243
 244         /* Check to see if this is a device file, or link */
 245         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 246          || (preserve_specials && IS_SPECIAL(file->mode))) {
 247                 int save_errno;
 248                 do_unlink(buf);
 249                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0) {
 250                         save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 251                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
 252                                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
 253                                         save_errno = errno ? errno : save_errno;
 254                                 else
 255                                         save_errno = 0;
 256                         }
 257                         if (save_errno) {
 258                                 rsyserr(FERROR, save_errno, "mknod %s failed",
 259                                         full_fname(buf));
 260                         }
 261                 } else
 262                         save_errno = 0;
 263                 if (verbose > 2 && save_errno == 0) {
 264                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 265                                 fname);
 266                 }
 267                 kept = 1;
 268                 do_unlink(fname);
 269         }
 270
 271         if (!kept && S_ISDIR(file->mode)) {
 272                 /* make an empty directory */
 273                 if (do_mkdir(buf, file->mode) < 0) {
 274                         int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 275                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
 276                                 if (do_mkdir(buf, file->mode) < 0)
 277                                         save_errno = errno ? errno : save_errno;
 278                                 else
 279                                         save_errno = 0;
 280                         }
 281                         if (save_errno) {
 282                                 rsyserr(FINFO, save_errno, "mkdir %s failed",
 283                                         full_fname(buf));
 284                         }
 285                 }
 286
 287                 ret_code = do_rmdir(fname);
 288                 if (verbose > 2) {
 289                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 290                                 full_fname(fname), ret_code);
 291                 }
 292                 kept = 1;
 293         }
 294
 295 #ifdef SUPPORT_LINKS
 296         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 297                 const char *sl = F_SYMLINK(file);
 298                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 299                         if (verbose) {
 300                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 301                                         full_fname(buf), sl);
 302                         }
 303                         kept = 1;
 304                 } else {
 305                         do_unlink(buf);
 306                         if (do_symlink(sl, buf) < 0) {
 307                                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 308                                 if (errno == ENOENT && make_bak_dir(buf) == 0) {
 309                                         if (do_symlink(sl, buf) < 0)
 310                                                 save_errno = errno ? errno : save_errno;
 311                                         else
 312                                                 save_errno = 0;
 313                                 }
 314                                 if (save_errno) {
 315                                         rsyserr(FERROR, save_errno, "link %s -> \"%s\"",
 316                                                 full_fname(buf), sl);
 317                                 }
 318                         }
 319                         do_unlink(fname);
 320                         kept = 1;
 321                 }
 322         }
 323 #endif
 324
 325         if (!kept && !S_ISREG(file->mode)) {
 326                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 327                         fname);
 328                 unmake_file(file);
 329                 return 1;
 330         }
 331
 332         /* move to keep tree if a file */
 333         if (!kept) {
 334                 if (robust_move(fname, buf) != 0) {
 335                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 336                                 full_fname(fname), buf);
 337                 } else if (sx.st.st_nlink > 1) {
 338                         /* If someone has hard-linked the file into the backup
 339                          * dir, rename() might return success but do nothing! */
 340                         robust_unlink(fname); /* Just in case... */
 341                 }
 342         }
 343         preserve_xattrs = 0;
 344         set_file_attrs(buf, file, NULL, fname, 0);
 345         preserve_xattrs = save_preserve_xattrs;
 346         unmake_file(file);
 347
 348         if (verbose > 1) {
 349                 rprintf(FINFO, "backed up %s to %s\n",
 350                         fname, buf);
 351         }
 352         return 1;
 353 }
 354
 355
 356 /* main backup switch routine */
 357 int make_backup(const char *fname)
 358 {
 359         if (backup_dir)
 360                 return keep_backup(fname);
 361         return make_simple_backup(fname);
 362 }