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 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         STRUCT_STAT st;
  97         char *rel = fullpath + backup_dir_len;
  98         char *end = rel + strlen(rel);
  99         char *p = end;
 100
 101         while (strncmp(fullpath, "./", 2) == 0)
 102                 fullpath += 2;
 103
 104         /* Try to find an existing dir, starting from the deepest dir. */
 105         while (1) {
 106                 if (--p == fullpath) {
 107                         p += strlen(p);
 108                         goto failure;
 109                 }
 110                 if (*p == '/') {
 111                         *p = '\0';
 112                         if (mkdir_defmode(fullpath) == 0)
 113                                 break;
 114                         if (errno != ENOENT) {
 115                                 rsyserr(FERROR, errno,
 116                                         "make_bak_dir mkdir %s failed",
 117                                         full_fname(fullpath));
 118                                 goto failure;
 119                         }
 120                 }
 121         }
 122
 123         /* Make all the dirs that we didn't find on the way here. */
 124         while (1) {
 125                 if (p >= rel) {
 126                         /* Try to transfer the directory settings of the
 127                          * actual dir that the files are coming from. */
 128                         if (do_stat(rel, &st) < 0) {
 129                                 rsyserr(FERROR, errno,
 130                                         "make_bak_dir stat %s failed",
 131                                         full_fname(rel));
 132                         } else {
 133                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 134 #ifdef HAVE_CHMOD
 135                                 do_chmod(fullpath, st.st_mode);
 136 #endif
 137                         }
 138                 }
 139                 *p = '/';
 140                 p += strlen(p);
 141                 if (p == end)
 142                         break;
 143                 if (mkdir_defmode(fullpath) < 0) {
 144                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 145                                 full_fname(fullpath));
 146                         goto failure;
 147                 }
 148         }
 149         return 0;
 150
 151   failure:
 152         while (p != end) {
 153                 *p = '/';
 154                 p += strlen(p);
 155         }
 156         return -1;
 157 }
 158
 159 /* robustly move a file, creating new directory structures if necessary */
 160 static int robust_move(const char *src, char *dst)
 161 {
 162         if (robust_rename(src, dst, NULL, 0755) < 0
 163          && (errno != ENOENT || make_bak_dir(dst) < 0
 164           || robust_rename(src, dst, NULL, 0755) < 0))
 165                 return -1;
 166         return 0;
 167 }
 168
 169
 170 /* If we have a --backup-dir, then we get here from make_backup().
 171  * We will move the file to be deleted into a parallel directory tree. */
 172 static int keep_backup(const char *fname)
 173 {
 174         STRUCT_STAT st;
 175         struct file_struct *file;
 176         char *buf;
 177         int kept = 0;
 178         int ret_code;
 179
 180         /* return if no file to keep */
 181         if (do_lstat(fname, &st) < 0)
 182                 return 1;
 183
 184         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 185                 return 1; /* the file could have disappeared */
 186
 187         if (!(buf = get_backup_name(fname))) {
 188                 unmake_file(file);
 189                 return 0;
 190         }
 191
 192         /* Check to see if this is a device file, or link */
 193         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 194          || (preserve_specials && IS_SPECIAL(file->mode))) {
 195                 uint32 *devp = F_RDEV_P(file);
 196                 dev_t rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 197                 do_unlink(buf);
 198                 if (do_mknod(buf, file->mode, rdev) < 0
 199                     && (errno != ENOENT || make_bak_dir(buf) < 0
 200                      || do_mknod(buf, file->mode, rdev) < 0)) {
 201                         rsyserr(FERROR, errno, "mknod %s failed",
 202                                 full_fname(buf));
 203                 } else if (verbose > 2) {
 204                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 205                                 fname);
 206                 }
 207                 kept = 1;
 208                 do_unlink(fname);
 209         }
 210
 211         if (!kept && S_ISDIR(file->mode)) {
 212                 /* make an empty directory */
 213                 if (do_mkdir(buf, file->mode) < 0
 214                     && (errno != ENOENT || make_bak_dir(buf) < 0
 215                      || do_mkdir(buf, file->mode) < 0)) {
 216                         rsyserr(FINFO, errno, "mkdir %s failed",
 217                                 full_fname(buf));
 218                 }
 219
 220                 ret_code = do_rmdir(fname);
 221                 if (verbose > 2) {
 222                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 223                                 full_fname(fname), ret_code);
 224                 }
 225                 kept = 1;
 226         }
 227
 228 #ifdef SUPPORT_LINKS
 229         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 230                 const char *sl = F_SYMLINK(file);
 231                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 232                         if (verbose) {
 233                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 234                                         full_fname(buf), sl);
 235                         }
 236                         kept = 1;
 237                 } else {
 238                         do_unlink(buf);
 239                         if (do_symlink(sl, buf) < 0
 240                             && (errno != ENOENT || make_bak_dir(buf) < 0
 241                              || do_symlink(sl, buf) < 0)) {
 242                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 243                                         full_fname(buf), sl);
 244                         }
 245                         do_unlink(fname);
 246                         kept = 1;
 247                 }
 248         }
 249 #endif
 250
 251         if (!kept && !S_ISREG(file->mode)) {
 252                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 253                         fname);
 254                 unmake_file(file);
 255                 return 1;
 256         }
 257
 258         /* move to keep tree if a file */
 259         if (!kept) {
 260                 if (robust_move(fname, buf) != 0) {
 261                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 262                                 full_fname(fname), buf);
 263                 } else if (st.st_nlink > 1) {
 264                         /* If someone has hard-linked the file into the backup
 265                          * dir, rename() might return success but do nothing! */
 266                         robust_unlink(fname); /* Just in case... */
 267                 }
 268         }
 269         set_file_attrs(buf, file, NULL, 0);
 270         unmake_file(file);
 271
 272         if (verbose > 1) {
 273                 rprintf(FINFO, "backed up %s to %s\n",
 274                         fname, buf);
 275         }
 276         return 1;
 277 }
 278
 279
 280 /* main backup switch routine */
 281 int make_backup(const char *fname)
 282 {
 283         if (backup_dir)
 284                 return keep_backup(fname);
 285         return make_simple_backup(fname);
 286 }