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 version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  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_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 (verbose > 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 static int make_bak_dir(char *fullpath)
  95 {
  96         statx sx;
  97         struct file_struct *file;
  98         char *rel = fullpath + backup_dir_len;
  99         char *end = rel + strlen(rel);
 100         char *p = end;
 101
 102         while (strncmp(fullpath, "./", 2) == 0)
 103                 fullpath += 2;
 104
 105         /* Try to find an existing dir, starting from the deepest dir. */
 106         while (1) {
 107                 if (--p == fullpath) {
 108                         p += strlen(p);
 109                         goto failure;
 110                 }
 111                 if (*p == '/') {
 112                         *p = '\0';
 113                         if (mkdir_defmode(fullpath) == 0)
 114                                 break;
 115                         if (errno != ENOENT) {
 116                                 rsyserr(FERROR, errno,
 117                                         "make_bak_dir mkdir %s failed",
 118                                         full_fname(fullpath));
 119                                 goto failure;
 120                         }
 121                 }
 122         }
 123
 124         /* Make all the dirs that we didn't find on the way here. */
 125         while (1) {
 126                 if (p >= rel) {
 127                         /* Try to transfer the directory settings of the
 128                          * actual dir that the files are coming from. */
 129                         if (do_stat(rel, &sx.st) < 0) {
 130                                 rsyserr(FERROR, errno,
 131                                         "make_bak_dir stat %s failed",
 132                                         full_fname(rel));
 133                         } else {
 134 #ifdef SUPPORT_ACLS
 135                                 sx.acc_acl = sx.def_acl = NULL;
 136 #endif
 137                                 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
 138                                         continue;
 139 #ifdef SUPPORT_ACLS
 140                                 if (preserve_acls && !S_ISLNK(file->mode)) {
 141                                         get_acl(rel, &sx);
 142                                         cache_acl(file, &sx);
 143                                         free_acl(&sx);
 144                                 }
 145 #endif
 146                                 set_file_attrs(fullpath, file, NULL, 0);
 147                                 free(file);
 148                         }
 149                 }
 150                 *p = '/';
 151                 p += strlen(p);
 152                 if (p == end)
 153                         break;
 154                 if (mkdir_defmode(fullpath) < 0) {
 155                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 156                                 full_fname(fullpath));
 157                         goto failure;
 158                 }
 159         }
 160         return 0;
 161
 162   failure:
 163         while (p != end) {
 164                 *p = '/';
 165                 p += strlen(p);
 166         }
 167         return -1;
 168 }
 169
 170 /* robustly move a file, creating new directory structures if necessary */
 171 static int robust_move(const char *src, char *dst)
 172 {
 173         if (robust_rename(src, dst, NULL, 0755) < 0
 174          && (errno != ENOENT || make_bak_dir(dst) < 0
 175           || robust_rename(src, dst, NULL, 0755) < 0))
 176                 return -1;
 177         return 0;
 178 }
 179
 180
 181 /* If we have a --backup-dir, then we get here from make_backup().
 182  * We will move the file to be deleted into a parallel directory tree. */
 183 static int keep_backup(const char *fname)
 184 {
 185         statx sx;
 186         struct file_struct *file;
 187         char *buf;
 188         int kept = 0;
 189         int ret_code;
 190
 191         /* return if no file to keep */
 192         if (do_lstat(fname, &sx.st) < 0)
 193                 return 1;
 194 #ifdef SUPPORT_ACLS
 195         sx.acc_acl = sx.def_acl = NULL;
 196 #endif
 197
 198         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 199                 return 1; /* the file could have disappeared */
 200
 201         if (!(buf = get_backup_name(fname))) {
 202                 unmake_file(file);
 203                 return 0;
 204         }
 205
 206 #ifdef SUPPORT_ACLS
 207         if (preserve_acls && !S_ISLNK(file->mode)) {
 208                 get_acl(fname, &sx);
 209                 cache_acl(file, &sx);
 210                 free_acl(&sx);
 211         }
 212 #endif
 213
 214         /* Check to see if this is a device file, or link */
 215         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 216          || (preserve_specials && IS_SPECIAL(file->mode))) {
 217                 uint32 *devp = F_RDEV_P(file);
 218                 dev_t rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 219                 do_unlink(buf);
 220                 if (do_mknod(buf, file->mode, rdev) < 0
 221                     && (errno != ENOENT || make_bak_dir(buf) < 0
 222                      || do_mknod(buf, file->mode, rdev) < 0)) {
 223                         rsyserr(FERROR, errno, "mknod %s failed",
 224                                 full_fname(buf));
 225                 } else if (verbose > 2) {
 226                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 227                                 fname);
 228                 }
 229                 kept = 1;
 230                 do_unlink(fname);
 231         }
 232
 233         if (!kept && S_ISDIR(file->mode)) {
 234                 /* make an empty directory */
 235                 if (do_mkdir(buf, file->mode) < 0
 236                     && (errno != ENOENT || make_bak_dir(buf) < 0
 237                      || do_mkdir(buf, file->mode) < 0)) {
 238                         rsyserr(FINFO, errno, "mkdir %s failed",
 239                                 full_fname(buf));
 240                 }
 241
 242                 ret_code = do_rmdir(fname);
 243                 if (verbose > 2) {
 244                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 245                                 full_fname(fname), ret_code);
 246                 }
 247                 kept = 1;
 248         }
 249
 250 #ifdef SUPPORT_LINKS
 251         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 252                 const char *sl = F_SYMLINK(file);
 253                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 254                         if (verbose) {
 255                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 256                                         full_fname(buf), sl);
 257                         }
 258                         kept = 1;
 259                 } else {
 260                         do_unlink(buf);
 261                         if (do_symlink(sl, buf) < 0
 262                             && (errno != ENOENT || make_bak_dir(buf) < 0
 263                              || do_symlink(sl, buf) < 0)) {
 264                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 265                                         full_fname(buf), sl);
 266                         }
 267                         do_unlink(fname);
 268                         kept = 1;
 269                 }
 270         }
 271 #endif
 272
 273         if (!kept && !S_ISREG(file->mode)) {
 274                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 275                         fname);
 276                 unmake_file(file);
 277                 return 1;
 278         }
 279
 280         /* move to keep tree if a file */
 281         if (!kept) {
 282                 if (robust_move(fname, buf) != 0) {
 283                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 284                                 full_fname(fname), buf);
 285                 } else if (sx.st.st_nlink > 1) {
 286                         /* If someone has hard-linked the file into the backup
 287                          * dir, rename() might return success but do nothing! */
 288                         robust_unlink(fname); /* Just in case... */
 289                 }
 290         }
 291         set_file_attrs(buf, file, NULL, 0);
 292         unmake_file(file);
 293
 294         if (verbose > 1) {
 295                 rprintf(FINFO, "backed up %s to %s\n",
 296                         fname, buf);
 297         }
 298         return 1;
 299 }
 300
 301
 302 /* main backup switch routine */
 303 int make_backup(const char *fname)
 304 {
 305         if (backup_dir)
 306                 return keep_backup(fname);
 307         return make_simple_backup(fname);
 308 }