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_devices;
  26 extern int preserve_specials;
  27 extern int preserve_links;
  28 extern int safe_symlinks;
  29 extern int backup_dir_len;
  30 extern unsigned int backup_dir_remainder;
  31 extern char backup_dir_buf[MAXPATHLEN];
  32 extern char *backup_suffix;
  33 extern char *backup_dir;
  34
  35 /* make a complete pathname for backup file */
  36 char *get_backup_name(const char *fname)
  37 {
  38         if (backup_dir) {
  39                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
  40                                fname, backup_suffix, NULL) < backup_dir_remainder)
  41                         return backup_dir_buf;
  42         } else {
  43                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
  44                                fname, backup_suffix, NULL) < MAXPATHLEN)
  45                         return backup_dir_buf;
  46         }
  47
  48         rprintf(FERROR, "backup filename too long\n");
  49         return NULL;
  50 }
  51
  52 /* simple backup creates a backup with a suffix in the same directory */
  53 static int make_simple_backup(const char *fname)
  54 {
  55         int rename_errno;
  56         const char *fnamebak = get_backup_name(fname);
  57
  58         if (!fnamebak)
  59                 return 0;
  60
  61         while (1) {
  62                 if (do_rename(fname, fnamebak) == 0) {
  63                         if (verbose > 1) {
  64                                 rprintf(FINFO, "backed up %s to %s\n",
  65                                         fname, fnamebak);
  66                         }
  67                         break;
  68                 }
  69                 /* cygwin (at least version b19) reports EINVAL */
  70                 if (errno == ENOENT || errno == EINVAL)
  71                         break;
  72
  73                 rename_errno = errno;
  74                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
  75                         continue;
  76                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
  77                         continue;
  78
  79                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
  80                         fname, fnamebak);
  81                 errno = rename_errno;
  82                 return 0;
  83         }
  84
  85         return 1;
  86 }
  87
  88
  89 /****************************************************************************
  90 Create a directory given an absolute path, perms based upon another directory
  91 path
  92 ****************************************************************************/
  93 static int make_bak_dir(char *fullpath)
  94 {
  95         STRUCT_STAT st;
  96         char *rel = fullpath + backup_dir_len;
  97         char *end = rel + strlen(rel);
  98         char *p = end;
  99
 100         while (strncmp(fullpath, "./", 2) == 0)
 101                 fullpath += 2;
 102
 103         /* Try to find an existing dir, starting from the deepest dir. */
 104         while (1) {
 105                 if (--p == fullpath) {
 106                         p += strlen(p);
 107                         goto failure;
 108                 }
 109                 if (*p == '/') {
 110                         *p = '\0';
 111                         if (mkdir_defmode(fullpath) == 0)
 112                                 break;
 113                         if (errno != ENOENT) {
 114                                 rsyserr(FERROR, errno,
 115                                         "make_bak_dir mkdir %s failed",
 116                                         full_fname(fullpath));
 117                                 goto failure;
 118                         }
 119                 }
 120         }
 121
 122         /* Make all the dirs that we didn't find on the way here. */
 123         while (1) {
 124                 if (p >= rel) {
 125                         /* Try to transfer the directory settings of the
 126                          * actual dir that the files are coming from. */
 127                         if (do_stat(rel, &st) < 0) {
 128                                 rsyserr(FERROR, errno,
 129                                         "make_bak_dir stat %s failed",
 130                                         full_fname(rel));
 131                         } else {
 132                                 do_lchown(fullpath, st.st_uid, st.st_gid);
 133 #ifdef HAVE_CHMOD
 134                                 do_chmod(fullpath, st.st_mode);
 135 #endif
 136                         }
 137                 }
 138                 *p = '/';
 139                 p += strlen(p);
 140                 if (p == end)
 141                         break;
 142                 if (mkdir_defmode(fullpath) < 0) {
 143                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
 144                                 full_fname(fullpath));
 145                         goto failure;
 146                 }
 147         }
 148         return 0;
 149
 150   failure:
 151         while (p != end) {
 152                 *p = '/';
 153                 p += strlen(p);
 154         }
 155         return -1;
 156 }
 157
 158 /* robustly move a file, creating new directory structures if necessary */
 159 static int robust_move(const char *src, char *dst)
 160 {
 161         if (robust_rename(src, dst, NULL, 0755) < 0
 162          && (errno != ENOENT || make_bak_dir(dst) < 0
 163           || robust_rename(src, dst, NULL, 0755) < 0))
 164                 return -1;
 165         return 0;
 166 }
 167
 168
 169 /* If we have a --backup-dir, then we get here from make_backup().
 170  * We will move the file to be deleted into a parallel directory tree. */
 171 static int keep_backup(const char *fname)
 172 {
 173         STRUCT_STAT st;
 174         struct file_struct *file;
 175         char *buf;
 176         int kept = 0;
 177         int ret_code;
 178
 179         /* return if no file to keep */
 180         if (do_lstat(fname, &st) < 0)
 181                 return 1;
 182
 183         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
 184                 return 1; /* the file could have disappeared */
 185
 186         if (!(buf = get_backup_name(fname))) {
 187                 unmake_file(file);
 188                 return 0;
 189         }
 190
 191         /* Check to see if this is a device file, or link */
 192         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
 193          || (preserve_specials && IS_SPECIAL(file->mode))) {
 194                 uint32 *devp = F_RDEV_P(file);
 195                 dev_t rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
 196                 do_unlink(buf);
 197                 if (do_mknod(buf, file->mode, rdev) < 0
 198                     && (errno != ENOENT || make_bak_dir(buf) < 0
 199                      || do_mknod(buf, file->mode, rdev) < 0)) {
 200                         rsyserr(FERROR, errno, "mknod %s failed",
 201                                 full_fname(buf));
 202                 } else if (verbose > 2) {
 203                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
 204                                 fname);
 205                 }
 206                 kept = 1;
 207                 do_unlink(fname);
 208         }
 209
 210         if (!kept && S_ISDIR(file->mode)) {
 211                 /* make an empty directory */
 212                 if (do_mkdir(buf, file->mode) < 0
 213                     && (errno != ENOENT || make_bak_dir(buf) < 0
 214                      || do_mkdir(buf, file->mode) < 0)) {
 215                         rsyserr(FINFO, errno, "mkdir %s failed",
 216                                 full_fname(buf));
 217                 }
 218
 219                 ret_code = do_rmdir(fname);
 220                 if (verbose > 2) {
 221                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
 222                                 full_fname(fname), ret_code);
 223                 }
 224                 kept = 1;
 225         }
 226
 227 #ifdef SUPPORT_LINKS
 228         if (!kept && preserve_links && S_ISLNK(file->mode)) {
 229                 const char *sl = F_SYMLINK(file);
 230                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
 231                         if (verbose) {
 232                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
 233                                         full_fname(buf), sl);
 234                         }
 235                         kept = 1;
 236                 } else {
 237                         do_unlink(buf);
 238                         if (do_symlink(sl, buf) < 0
 239                             && (errno != ENOENT || make_bak_dir(buf) < 0
 240                              || do_symlink(sl, buf) < 0)) {
 241                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
 242                                         full_fname(buf), sl);
 243                         }
 244                         do_unlink(fname);
 245                         kept = 1;
 246                 }
 247         }
 248 #endif
 249
 250         if (!kept && !S_ISREG(file->mode)) {
 251                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
 252                         fname);
 253                 unmake_file(file);
 254                 return 1;
 255         }
 256
 257         /* move to keep tree if a file */
 258         if (!kept) {
 259                 if (robust_move(fname, buf) != 0) {
 260                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
 261                                 full_fname(fname), buf);
 262                 } else if (st.st_nlink > 1) {
 263                         /* If someone has hard-linked the file into the backup
 264                          * dir, rename() might return success but do nothing! */
 265                         robust_unlink(fname); /* Just in case... */
 266                 }
 267         }
 268         set_file_attrs(buf, file, NULL, 0);
 269         unmake_file(file);
 270
 271         if (verbose > 1) {
 272                 rprintf(FINFO, "backed up %s to %s\n",
 273                         fname, buf);
 274         }
 275         return 1;
 276 }
 277
 278
 279 /* main backup switch routine */
 280 int make_backup(const char *fname)
 281 {
 282         if (backup_dir)
 283                 return keep_backup(fname);
 284         return make_simple_backup(fname);
 285 }