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