backup.c

   1 /*
   2  * Backup handling code.
   3  *
   4  * Copyright (C) 1999 Andrew Tridgell
   5  * Copyright (C) 2003, 2004, 2005, 2006 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 2 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, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.
  20  */
  21
  22 #include "rsync.h"
  23
  24 extern int verbose;
  25 extern int am_root;
  26 extern int preserve_devices;
  27 extern int preserve_specials;
  28 extern int preserve_links;
  29 extern int safe_symlinks;
  30 extern int flist_extra_ndx;
  31 extern int file_struct_len;
  32 extern int backup_dir_len;
  33 extern unsigned int backup_dir_remainder;
  34 extern char backup_dir_buf[MAXPATHLEN];
  35 extern char *backup_suffix;
  36 extern char *backup_dir;
  37
  38 /* make a complete pathname for backup file */
  39 char *get_backup_name(const char *fname)
  40 {
  41         if (backup_dir) {
  42                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  43                                fname, backup_suffix, NULL) < backup_dir_remainder)
  44                         return backup_dir_buf;
  45         } else {
  46                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  47                                fname, backup_suffix, NULL) < MAXPATHLEN)
  48                         return backup_dir_buf;
  49         }
  50
  51         rprintf(FERROR, "backup filename too long\n");
  52         return NULL;
  53 }
  54
  55 /* simple backup creates a backup with a suffix in the same directory */
  56 static int make_simple_backup(const char *fname)
  57 {
  58         int rename_errno;
  59         const char *fnamebak = get_backup_name(fname);
  60
  61         if (!fnamebak)
  62                 return 0;
  63
  64         while (1) {
  65                 if (do_rename(fname, fnamebak) == 0) {
  66                         if (verbose > 1) {
  67                                 rprintf(FINFO, "backed up %s to %s\n",
  68                                         fname, fnamebak);
  69                         }
  70                         break;
  71                 }
  72                 /* cygwin (at least version b19) reports EINVAL */
  73                 if (errno == ENOENT || errno == EINVAL)
  74                         break;
  75
  76                 rename_errno = errno;
  77                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  78                         continue;
  79                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  80                         continue;
  81
  82                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  83                         fname, fnamebak);
  84                 errno = rename_errno;
  85                 return 0;
  86         }
  87
  88         return 1;
  89 }
  90
  91
  92 /****************************************************************************
  93 Create a directory given an absolute path, perms based upon another directory
  94 path
  95 ****************************************************************************/
  96 static int make_bak_dir(char *fullpath)
  97 {
  98         STRUCT_STAT st;
  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 (do_stat(rel, &st) < 0) {
 131                                 rsyserr(FERROR, errno,
 132                                         "make_bak_dir stat %s failed",
 133                                         full_fname(rel));
 134                         } else {
 135                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 136 #ifdef HAVE_CHMOD
 137                                 do_chmod(fullpath, st.st_mode);
 138 #endif
 139                         }
 140                 }
 141                 *p = '/';
 142                 p += strlen(p);
 143                 if (p == end)
 144                         break;
 145                 if (mkdir_defmode(fullpath) < 0) {
 146                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 147                                 full_fname(fullpath));
 148                         goto failure;
 149                 }
 150         }
 151         return 0;
 152
 153   failure:
 154         while (p != end) {
 155                 *p = '/';
 156                 p += strlen(p);
 157         }
 158         return -1;
 159 }
 160
 161 /* robustly move a file, creating new directory structures if necessary */
 162 static int robust_move(const char *src, char *dst)
 163 {
 164         if (robust_rename(src, dst, NULL, 0755) < 0
 165          && (errno != ENOENT || make_bak_dir(dst) < 0
 166           || robust_rename(src, dst, NULL, 0755) < 0))
 167                 return -1;
 168         return 0;
 169 }
 170
 171
 172 /* If we have a --backup-dir, then we get here from make_backup().
 173  * We will move the file to be deleted into a parallel directory tree. */
 174 static int keep_backup(const char *fname)
 175 {
 176         STRUCT_STAT st;
 177         struct file_struct *file;
 178         char *buf;
 179         int kept = 0;
 180         int ret_code;
 181
 182         /* return if no file to keep */
 183         if (do_lstat(fname, &st) < 0)
 184                 return 1;
 185
 186         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 187                 return 1; /* the file could have disappeared */
 188
 189         if (!(buf = get_backup_name(fname))) {
 190                 unmake_file(file);
 191                 return 0;
 192         }
 193
 194         /* Check to see if this is a device file, or link */
 195         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 196          || (preserve_specials && IS_SPECIAL(file->mode))) {
 197                 dev_t rdev = MAKEDEV(F_DMAJOR(file), F_DMINOR(file));
 198                 do_unlink(buf);
 199                 if (do_mknod(buf, file->mode, rdev) < 0
 200                     && (errno != ENOENT || make_bak_dir(buf) < 0
 201                      || do_mknod(buf, file->mode, rdev) < 0)) {
 202                         rsyserr(FERROR, errno, "mknod %s failed",
 203                                 full_fname(buf));
 204                 } else if (verbose > 2) {
 205                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 206                                 fname);
 207                 }
 208                 kept = 1;
 209                 do_unlink(fname);
 210         }
 211
 212         if (!kept && S_ISDIR(file->mode)) {
 213                 /* make an empty directory */
 214                 if (do_mkdir(buf, file->mode) < 0
 215                     && (errno != ENOENT || make_bak_dir(buf) < 0
 216                      || do_mkdir(buf, file->mode) < 0)) {
 217                         rsyserr(FINFO, errno, "mkdir %s failed",
 218                                 full_fname(buf));
 219                 }
 220
 221                 ret_code = do_rmdir(fname);
 222                 if (verbose > 2) {
 223                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 224                                 full_fname(fname), ret_code);
 225                 }
 226                 kept = 1;
 227         }
 228
 229 #ifdef SUPPORT_LINKS
 230         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 231                 const char *sl = F_SYMLINK(file);
 232                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 233                         if (verbose) {
 234                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 235                                         full_fname(buf), sl);
 236                         }
 237                         kept = 1;
 238                 } else {
 239                         do_unlink(buf);
 240                         if (do_symlink(sl, buf) < 0
 241                             && (errno != ENOENT || make_bak_dir(buf) < 0
 242                              || do_symlink(sl, buf) < 0)) {
 243                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 244                                         full_fname(buf), sl);
 245                         }
 246                         do_unlink(fname);
 247                         kept = 1;
 248                 }
 249         }
 250 #endif
 251
 252         if (!kept && !S_ISREG(file->mode)) {
 253                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 254                         fname);
 255                 unmake_file(file);
 256                 return 1;
 257         }
 258
 259         /* move to keep tree if a file */
 260         if (!kept) {
 261                 if (robust_move(fname, buf) != 0) {
 262                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 263                                 full_fname(fname), buf);
 264                 } else if (st.st_nlink > 1) {
 265                         /* If someone has hard-linked the file into the backup
 266                          * dir, rename() might return success but do nothing! */
 267                         robust_unlink(fname); /* Just in case... */
 268                 }
 269         }
 270         set_file_attrs(buf, file, NULL, 0);
 271         unmake_file(file);
 272
 273         if (verbose > 1) {
 274                 rprintf(FINFO, "backed up %s to %s\n",
 275                         fname, buf);
 276         }
 277         return 1;
 278 }
 279
 280
 281 /* main backup switch routine */
 282 int make_backup(const char *fname)
 283 {
 284         if (backup_dir)
 285                 return keep_backup(fname);
 286         return make_simple_backup(fname);
 287 }