backup.c

   1 /*
   2  * Backup handling code.
   3  *
   4  * Copyright (C) 1999 Andrew Tridgell
   5  * Copyright (C) 2003-2009 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 #include "ifuncs.h"
  23
  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 (INFO_GTE(BACKUP, 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                         init_stat_x(&sx);
 136                         if (x_stat(rel, &sx.st, NULL) < 0) {
 137                                 rsyserr(FERROR, errno,
 138                                         "make_bak_dir stat %s failed",
 139                                         full_fname(rel));
 140                         } else {
 141                                 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
 142                                         continue;
 143 #ifdef SUPPORT_ACLS
 144                                 if (preserve_acls && !S_ISLNK(file->mode)) {
 145                                         get_acl(rel, &sx);
 146                                         cache_acl(file, &sx);
 147                                         free_acl(&sx);
 148                                 }
 149 #endif
 150 #ifdef SUPPORT_XATTRS
 151                                 if (preserve_xattrs) {
 152                                         get_xattr(rel, &sx);
 153                                         cache_xattr(file, &sx);
 154                                         free_xattr(&sx);
 155                                 }
 156 #endif
 157                                 set_file_attrs(fbuf, file, NULL, NULL, 0);
 158                                 unmake_file(file);
 159                         }
 160                 }
 161                 *p = '/';
 162                 p += strlen(p);
 163                 if (p == end)
 164                         break;
 165                 if (mkdir_defmode(fbuf) < 0) {
 166                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 167                                 full_fname(fbuf));
 168                         return -1;
 169                 }
 170         }
 171
 172         return 0;
 173 }
 174
 175 /* robustly move a file, creating new directory structures if necessary */
 176 static int robust_move(const char *src, char *dst)
 177 {
 178         if (robust_rename(src, dst, NULL, 0755) < 0) {
 179                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 180                 if (errno == ENOENT && make_bak_dir(dst) == 0) {
 181                         if (robust_rename(src, dst, NULL, 0755) < 0)
 182                                 save_errno = errno ? errno : save_errno;
 183                         else
 184                                 save_errno = 0;
 185                 }
 186                 if (save_errno) {
 187                         errno = save_errno;
 188                         return -1;
 189                 }
 190         }
 191         return 0;
 192 }
 193
 194
 195 /* If we have a --backup-dir, then we get here from make_backup().
 196  * We will move the file to be deleted into a parallel directory tree. */
 197 static int keep_backup(const char *fname)
 198 {
 199         stat_x sx;
 200         struct file_struct *file;
 201         char *buf;
 202         int save_preserve_xattrs = preserve_xattrs;
 203         int kept = 0;
 204         int ret_code;
 205
 206         init_stat_x(&sx);
 207         /* Return success if no file to keep. */
 208         if (x_lstat(fname, &sx.st, NULL) < 0)
 209                 return 1;
 210
 211         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 212                 return 1; /* the file could have disappeared */
 213
 214         if (!(buf = get_backup_name(fname))) {
 215                 unmake_file(file);
 216                 return 0;
 217         }
 218
 219 #ifdef SUPPORT_ACLS
 220         if (preserve_acls && !S_ISLNK(file->mode)) {
 221                 get_acl(fname, &sx);
 222                 cache_acl(file, &sx);
 223                 free_acl(&sx);
 224         }
 225 #endif
 226 #ifdef SUPPORT_XATTRS
 227         if (preserve_xattrs) {
 228                 get_xattr(fname, &sx);
 229                 cache_xattr(file, &sx);
 230                 free_xattr(&sx);
 231         }
 232 #endif
 233
 234         /* Check to see if this is a device file, or link */
 235         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 236          || (preserve_specials && IS_SPECIAL(file->mode))) {
 237                 int save_errno;
 238                 do_unlink(buf);
 239                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0) {
 240                         save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 241                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
 242                                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
 243                                         save_errno = errno ? errno : save_errno;
 244                                 else
 245                                         save_errno = 0;
 246                         }
 247                         if (save_errno) {
 248                                 rsyserr(FERROR, save_errno, "mknod %s failed",
 249                                         full_fname(buf));
 250                         }
 251                 } else
 252                         save_errno = 0;
 253                 if (DEBUG_GTE(BACKUP, 1) && save_errno == 0) {
 254                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 255                                 fname);
 256                 }
 257                 kept = 1;
 258                 do_unlink(fname);
 259         }
 260
 261         if (!kept && S_ISDIR(file->mode)) {
 262                 /* make an empty directory */
 263                 if (do_mkdir(buf, file->mode) < 0) {
 264                         int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 265                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
 266                                 if (do_mkdir(buf, file->mode) < 0)
 267                                         save_errno = errno ? errno : save_errno;
 268                                 else
 269                                         save_errno = 0;
 270                         }
 271                         if (save_errno) {
 272                                 rsyserr(FINFO, save_errno, "mkdir %s failed",
 273                                         full_fname(buf));
 274                         }
 275                 }
 276
 277                 ret_code = do_rmdir(fname);
 278                 if (DEBUG_GTE(BACKUP, 1)) {
 279                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 280                                 full_fname(fname), ret_code);
 281                 }
 282                 kept = 1;
 283         }
 284
 285 #ifdef SUPPORT_LINKS
 286         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 287                 const char *sl = F_SYMLINK(file);
 288                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 289                         if (INFO_GTE(SYMSAFE, 1)) {
 290                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 291                                         full_fname(buf), sl);
 292                         }
 293                         kept = 1;
 294                 } else {
 295                         do_unlink(buf);
 296                         if (do_symlink(sl, buf) < 0) {
 297                                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
 298                                 if (errno == ENOENT && make_bak_dir(buf) == 0) {
 299                                         if (do_symlink(sl, buf) < 0)
 300                                                 save_errno = errno ? errno : save_errno;
 301                                         else
 302                                                 save_errno = 0;
 303                                 }
 304                                 if (save_errno) {
 305                                         rsyserr(FERROR, save_errno, "link %s -> \"%s\"",
 306                                                 full_fname(buf), sl);
 307                                 }
 308                         }
 309                         do_unlink(fname);
 310                         kept = 1;
 311                 }
 312         }
 313 #endif
 314
 315         if (!kept && !S_ISREG(file->mode)) {
 316                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 317                         fname);
 318                 unmake_file(file);
 319                 return 1;
 320         }
 321
 322         /* move to keep tree if a file */
 323         if (!kept) {
 324                 if (robust_move(fname, buf) != 0) {
 325                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 326                                 full_fname(fname), buf);
 327                 } else if (sx.st.st_nlink > 1) {
 328                         /* If someone has hard-linked the file into the backup
 329                          * dir, rename() might return success but do nothing! */
 330                         robust_unlink(fname); /* Just in case... */
 331                 }
 332         }
 333         preserve_xattrs = 0;
 334         set_file_attrs(buf, file, NULL, fname, 0);
 335         preserve_xattrs = save_preserve_xattrs;
 336         unmake_file(file);
 337
 338         if (INFO_GTE(BACKUP, 1)) {
 339                 rprintf(FINFO, "backed up %s to %s\n",
 340                         fname, buf);
 341         }
 342         return 1;
 343 }
 344
 345
 346 /* main backup switch routine */
 347 int make_backup(const char *fname)
 348 {
 349         if (backup_dir)
 350                 return keep_backup(fname);
 351         return make_simple_backup(fname);
 352 }