backup.c

   1 /*
   2  * Backup handling code.
   3  *
   4  * Copyright (C) 1999 Andrew Tridgell
   5  * Copyright (C) 2003-2007 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 static int make_bak_dir(char *fullpath)
  96 {
  97         statx sx;
  98         struct file_struct *file;
  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 (mkdir_defmode(fullpath) == 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 (x_stat(rel, &sx.st, NULL) < 0) {
 131                                 rsyserr(FERROR, errno,
 132                                         "make_bak_dir stat %s failed",
 133                                         full_fname(rel));
 134                         } else {
 135 #ifdef SUPPORT_ACLS
 136                                 sx.acc_acl = sx.def_acl = NULL;
 137 #endif
 138 #ifdef SUPPORT_XATTRS
 139                                 sx.xattr = NULL;
 140 #endif
 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(fullpath, 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(fullpath) < 0) {
 166                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 167                                 full_fname(fullpath));
 168                         goto failure;
 169                 }
 170         }
 171         return 0;
 172
 173   failure:
 174         while (p != end) {
 175                 *p = '/';
 176                 p += strlen(p);
 177         }
 178         return -1;
 179 }
 180
 181 /* robustly move a file, creating new directory structures if necessary */
 182 static int robust_move(const char *src, char *dst)
 183 {
 184         if (robust_rename(src, dst, NULL, 0755) < 0
 185          && (errno != ENOENT || make_bak_dir(dst) < 0
 186           || robust_rename(src, dst, NULL, 0755) < 0))
 187                 return -1;
 188         return 0;
 189 }
 190
 191
 192 /* If we have a --backup-dir, then we get here from make_backup().
 193  * We will move the file to be deleted into a parallel directory tree. */
 194 static int keep_backup(const char *fname)
 195 {
 196         statx sx;
 197         struct file_struct *file;
 198         char *buf;
 199         int kept = 0;
 200         int ret_code;
 201
 202         /* return if no file to keep */
 203         if (x_lstat(fname, &sx.st, NULL) < 0)
 204                 return 1;
 205 #ifdef SUPPORT_ACLS
 206         sx.acc_acl = sx.def_acl = NULL;
 207 #endif
 208 #ifdef SUPPORT_XATTRS
 209         sx.xattr = NULL;
 210 #endif
 211
 212         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 213                 return 1; /* the file could have disappeared */
 214
 215         if (!(buf = get_backup_name(fname))) {
 216                 unmake_file(file);
 217                 return 0;
 218         }
 219
 220 #ifdef SUPPORT_ACLS
 221         if (preserve_acls && !S_ISLNK(file->mode)) {
 222                 get_acl(fname, &sx);
 223                 cache_acl(file, &sx);
 224                 free_acl(&sx);
 225         }
 226 #endif
 227 #ifdef SUPPORT_XATTRS
 228         if (preserve_xattrs) {
 229                 get_xattr(fname, &sx);
 230                 cache_xattr(file, &sx);
 231                 free_xattr(&sx);
 232         }
 233 #endif
 234
 235         /* Check to see if this is a device file, or link */
 236         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 237          || (preserve_specials && IS_SPECIAL(file->mode))) {
 238                 uint32 *devp = F_RDEV_P(file);
 239                 dev_t rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 240                 do_unlink(buf);
 241                 if (do_mknod(buf, file->mode, rdev) < 0
 242                     && (errno != ENOENT || make_bak_dir(buf) < 0
 243                      || do_mknod(buf, file->mode, rdev) < 0)) {
 244                         rsyserr(FERROR, errno, "mknod %s failed",
 245                                 full_fname(buf));
 246                 } else if (verbose > 2) {
 247                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 248                                 fname);
 249                 }
 250                 kept = 1;
 251                 do_unlink(fname);
 252         }
 253
 254         if (!kept && S_ISDIR(file->mode)) {
 255                 /* make an empty directory */
 256                 if (do_mkdir(buf, file->mode) < 0
 257                     && (errno != ENOENT || make_bak_dir(buf) < 0
 258                      || do_mkdir(buf, file->mode) < 0)) {
 259                         rsyserr(FINFO, errno, "mkdir %s failed",
 260                                 full_fname(buf));
 261                 }
 262
 263                 ret_code = do_rmdir(fname);
 264                 if (verbose > 2) {
 265                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 266                                 full_fname(fname), ret_code);
 267                 }
 268                 kept = 1;
 269         }
 270
 271 #ifdef SUPPORT_LINKS
 272         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 273                 const char *sl = F_SYMLINK(file);
 274                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 275                         if (verbose) {
 276                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 277                                         full_fname(buf), sl);
 278                         }
 279                         kept = 1;
 280                 } else {
 281                         do_unlink(buf);
 282                         if (do_symlink(sl, buf) < 0
 283                             && (errno != ENOENT || make_bak_dir(buf) < 0
 284                              || do_symlink(sl, buf) < 0)) {
 285                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 286                                         full_fname(buf), sl);
 287                         }
 288                         do_unlink(fname);
 289                         kept = 1;
 290                 }
 291         }
 292 #endif
 293
 294         if (!kept && !S_ISREG(file->mode)) {
 295                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 296                         fname);
 297                 unmake_file(file);
 298                 return 1;
 299         }
 300
 301         /* move to keep tree if a file */
 302         if (!kept) {
 303                 if (robust_move(fname, buf) != 0) {
 304                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 305                                 full_fname(fname), buf);
 306                 } else if (sx.st.st_nlink > 1) {
 307                         /* If someone has hard-linked the file into the backup
 308                          * dir, rename() might return success but do nothing! */
 309                         robust_unlink(fname); /* Just in case... */
 310                 }
 311         }
 312         set_file_attrs(buf, file, NULL, fname, 0);
 313         unmake_file(file);
 314
 315         if (verbose > 1) {
 316                 rprintf(FINFO, "backed up %s to %s\n",
 317                         fname, buf);
 318         }
 319         return 1;
 320 }
 321
 322
 323 /* main backup switch routine */
 324 int make_backup(const char *fname)
 325 {
 326         if (backup_dir)
 327                 return keep_backup(fname);
 328         return make_simple_backup(fname);
 329 }