| 1 | /* |
| 2 | * Backup handling code. |
| 3 | * |
| 4 | * Copyright (C) 1999 Andrew Tridgell |
| 5 | * Copyright (C) 2003-2009 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 | #include "ifuncs.h" |
| 23 | |
| 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 | /* Returns -1 on error, 0 on missing dir, and 1 on present dir. */ |
| 38 | static int validate_backup_dir(void) |
| 39 | { |
| 40 | STRUCT_STAT st; |
| 41 | |
| 42 | if (do_lstat(backup_dir_buf, &st) < 0) { |
| 43 | if (errno == ENOENT) |
| 44 | return 0; |
| 45 | rsyserr(FERROR, errno, "backup lstat %s failed", backup_dir_buf); |
| 46 | return -1; |
| 47 | } |
| 48 | if (!S_ISDIR(st.st_mode)) { |
| 49 | int flags = get_del_for_flag(st.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE; |
| 50 | if (delete_item(backup_dir_buf, st.st_mode, flags) == 0) |
| 51 | return 0; |
| 52 | return -1; |
| 53 | } |
| 54 | return 1; |
| 55 | } |
| 56 | |
| 57 | /* Create a backup path from the given fname, putting the result into |
| 58 | * backup_dir_buf. Any new directories (compared to the prior backup |
| 59 | * path) are ensured to exist as directories, replacing anything else |
| 60 | * that may be in the way (e.g. a symlink). */ |
| 61 | static BOOL copy_valid_path(const char *fname) |
| 62 | { |
| 63 | const char *f; |
| 64 | int val; |
| 65 | BOOL ret = True; |
| 66 | stat_x sx; |
| 67 | char *b, *rel = backup_dir_buf + backup_dir_len, *name = rel; |
| 68 | |
| 69 | for (f = fname, b = rel; *f && *f == *b; f++, b++) { |
| 70 | if (*b == '/') |
| 71 | name = b + 1; |
| 72 | } |
| 73 | |
| 74 | if (stringjoin(rel, backup_dir_remainder, fname, backup_suffix, NULL) >= backup_dir_remainder) { |
| 75 | rprintf(FERROR, "backup filename too long\n"); |
| 76 | *name = '\0'; |
| 77 | return False; |
| 78 | } |
| 79 | |
| 80 | for ( ; ; name = b + 1) { |
| 81 | if ((b = strchr(name, '/')) == NULL) |
| 82 | return True; |
| 83 | *b = '\0'; |
| 84 | |
| 85 | val = validate_backup_dir(); |
| 86 | if (val == 0) |
| 87 | break; |
| 88 | if (val < 0) { |
| 89 | *name = '\0'; |
| 90 | return False; |
| 91 | } |
| 92 | |
| 93 | *b = '/'; |
| 94 | } |
| 95 | |
| 96 | init_stat_x(&sx); |
| 97 | |
| 98 | for ( ; b; name = b + 1, b = strchr(name, '/')) { |
| 99 | *b = '\0'; |
| 100 | |
| 101 | while (do_mkdir(backup_dir_buf, ACCESSPERMS) < 0) { |
| 102 | if (errno == EEXIST) { |
| 103 | val = validate_backup_dir(); |
| 104 | if (val > 0) |
| 105 | break; |
| 106 | if (val == 0) |
| 107 | continue; |
| 108 | } else |
| 109 | rsyserr(FERROR, errno, "backup mkdir %s failed", backup_dir_buf); |
| 110 | *name = '\0'; |
| 111 | ret = False; |
| 112 | goto cleanup; |
| 113 | } |
| 114 | |
| 115 | /* Try to transfer the directory settings of the actual dir |
| 116 | * that the files are coming from. */ |
| 117 | if (x_stat(rel, &sx.st, NULL) < 0) |
| 118 | rsyserr(FERROR, errno, "backup stat %s failed", full_fname(rel)); |
| 119 | else { |
| 120 | struct file_struct *file; |
| 121 | if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS))) |
| 122 | continue; |
| 123 | #ifdef SUPPORT_ACLS |
| 124 | if (preserve_acls && !S_ISLNK(file->mode)) { |
| 125 | get_acl(rel, &sx); |
| 126 | cache_tmp_acl(file, &sx); |
| 127 | free_acl(&sx); |
| 128 | } |
| 129 | #endif |
| 130 | #ifdef SUPPORT_XATTRS |
| 131 | if (preserve_xattrs) { |
| 132 | get_xattr(rel, &sx); |
| 133 | cache_tmp_xattr(file, &sx); |
| 134 | free_xattr(&sx); |
| 135 | } |
| 136 | #endif |
| 137 | set_file_attrs(backup_dir_buf, file, NULL, NULL, 0); |
| 138 | unmake_file(file); |
| 139 | } |
| 140 | |
| 141 | *b = '/'; |
| 142 | } |
| 143 | |
| 144 | cleanup: |
| 145 | |
| 146 | #ifdef SUPPORT_ACLS |
| 147 | uncache_tmp_acls(); |
| 148 | #endif |
| 149 | #ifdef SUPPORT_XATTRS |
| 150 | uncache_tmp_xattrs(); |
| 151 | #endif |
| 152 | |
| 153 | return ret; |
| 154 | } |
| 155 | |
| 156 | /* Make a complete pathname for backup file and verify any new path elements. */ |
| 157 | char *get_backup_name(const char *fname) |
| 158 | { |
| 159 | if (backup_dir) { |
| 160 | /* copy fname into backup_dir_buf while validating the dirs. */ |
| 161 | if (copy_valid_path(fname)) |
| 162 | return backup_dir_buf; |
| 163 | /* copy_valid_path() has printed an error message. */ |
| 164 | return NULL; |
| 165 | } |
| 166 | |
| 167 | if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN) |
| 168 | return backup_dir_buf; |
| 169 | |
| 170 | rprintf(FERROR, "backup filename too long\n"); |
| 171 | return NULL; |
| 172 | } |
| 173 | |
| 174 | /* Has same return codes as make_backup(). */ |
| 175 | static inline int link_or_rename(const char *from, const char *to, |
| 176 | BOOL prefer_rename, STRUCT_STAT *stp) |
| 177 | { |
| 178 | #ifdef SUPPORT_HARD_LINKS |
| 179 | if (!prefer_rename) { |
| 180 | #ifndef CAN_HARDLINK_SYMLINK |
| 181 | if (S_ISLNK(stp->st_mode)) |
| 182 | return 0; /* Use copy code. */ |
| 183 | #endif |
| 184 | #ifndef CAN_HARDLINK_SPECIAL |
| 185 | if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode)) |
| 186 | return 0; /* Use copy code. */ |
| 187 | #endif |
| 188 | if (do_link(from, to) == 0) { |
| 189 | if (DEBUG_GTE(BACKUP, 1)) |
| 190 | rprintf(FINFO, "make_backup: HLINK %s successful.\n", from); |
| 191 | return 2; |
| 192 | } |
| 193 | /* We prefer to rename a regular file rather than copy it. */ |
| 194 | if (!S_ISREG(stp->st_mode) || errno == EEXIST || errno == EISDIR) |
| 195 | return 0; |
| 196 | } |
| 197 | #endif |
| 198 | if (do_rename(from, to) == 0) { |
| 199 | if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) { |
| 200 | /* If someone has hard-linked the file into the backup |
| 201 | * dir, rename() might return success but do nothing! */ |
| 202 | robust_unlink(from); /* Just in case... */ |
| 203 | } |
| 204 | if (DEBUG_GTE(BACKUP, 1)) |
| 205 | rprintf(FINFO, "make_backup: RENAME %s successful.\n", from); |
| 206 | return 1; |
| 207 | } |
| 208 | return 0; |
| 209 | } |
| 210 | |
| 211 | /* Hard-link, rename, or copy an item to the backup name. Returns 2 if item |
| 212 | * was duplicated into backup area, 1 if item was moved, or 0 for failure.*/ |
| 213 | int make_backup(const char *fname, BOOL prefer_rename) |
| 214 | { |
| 215 | stat_x sx; |
| 216 | struct file_struct *file; |
| 217 | int save_preserve_xattrs; |
| 218 | char *buf = get_backup_name(fname); |
| 219 | int ret = 0; |
| 220 | |
| 221 | if (!buf) |
| 222 | return 0; |
| 223 | |
| 224 | init_stat_x(&sx); |
| 225 | /* Return success if no file to keep. */ |
| 226 | if (x_lstat(fname, &sx.st, NULL) < 0) |
| 227 | return 1; |
| 228 | |
| 229 | /* Try a hard-link or a rename first. Using rename is not atomic, but |
| 230 | * is more efficient than forcing a copy for larger files when no hard- |
| 231 | * linking is possible. */ |
| 232 | if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0) |
| 233 | goto success; |
| 234 | if (errno == EEXIST || errno == EISDIR) { |
| 235 | STRUCT_STAT bakst; |
| 236 | if (do_lstat(buf, &bakst) == 0) { |
| 237 | int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE; |
| 238 | if (delete_item(buf, bakst.st_mode, flags) != 0) |
| 239 | return 0; |
| 240 | } |
| 241 | if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0) |
| 242 | goto success; |
| 243 | } |
| 244 | |
| 245 | /* Fall back to making a copy. */ |
| 246 | if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS))) |
| 247 | return 1; /* the file could have disappeared */ |
| 248 | |
| 249 | #ifdef SUPPORT_ACLS |
| 250 | if (preserve_acls && !S_ISLNK(file->mode)) { |
| 251 | get_acl(fname, &sx); |
| 252 | cache_tmp_acl(file, &sx); |
| 253 | free_acl(&sx); |
| 254 | } |
| 255 | #endif |
| 256 | #ifdef SUPPORT_XATTRS |
| 257 | if (preserve_xattrs) { |
| 258 | get_xattr(fname, &sx); |
| 259 | cache_tmp_xattr(file, &sx); |
| 260 | free_xattr(&sx); |
| 261 | } |
| 262 | #endif |
| 263 | |
| 264 | /* Check to see if this is a device file, or link */ |
| 265 | if ((am_root && preserve_devices && IS_DEVICE(file->mode)) |
| 266 | || (preserve_specials && IS_SPECIAL(file->mode))) { |
| 267 | if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0) |
| 268 | rsyserr(FERROR, errno, "mknod %s failed", full_fname(buf)); |
| 269 | else if (DEBUG_GTE(BACKUP, 1)) |
| 270 | rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname); |
| 271 | ret = 2; |
| 272 | } |
| 273 | |
| 274 | #ifdef SUPPORT_LINKS |
| 275 | if (!ret && preserve_links && S_ISLNK(file->mode)) { |
| 276 | const char *sl = F_SYMLINK(file); |
| 277 | if (safe_symlinks && unsafe_symlink(sl, fname)) { |
| 278 | if (INFO_GTE(SYMSAFE, 1)) { |
| 279 | rprintf(FINFO, "not backing up unsafe symlink \"%s\" -> \"%s\"\n", |
| 280 | fname, sl); |
| 281 | } |
| 282 | ret = 2; |
| 283 | } else { |
| 284 | if (do_symlink(sl, buf) < 0) |
| 285 | rsyserr(FERROR, errno, "link %s -> \"%s\"", full_fname(buf), sl); |
| 286 | else if (DEBUG_GTE(BACKUP, 1)) |
| 287 | rprintf(FINFO, "make_backup: SYMLINK %s successful.\n", fname); |
| 288 | ret = 2; |
| 289 | } |
| 290 | } |
| 291 | #endif |
| 292 | |
| 293 | if (!ret && !S_ISREG(file->mode)) { |
| 294 | rprintf(FINFO, "make_bak: skipping non-regular file %s\n", fname); |
| 295 | unmake_file(file); |
| 296 | #ifdef SUPPORT_ACLS |
| 297 | uncache_tmp_acls(); |
| 298 | #endif |
| 299 | #ifdef SUPPORT_XATTRS |
| 300 | uncache_tmp_xattrs(); |
| 301 | #endif |
| 302 | return 2; |
| 303 | } |
| 304 | |
| 305 | /* Copy to backup tree if a file. */ |
| 306 | if (!ret) { |
| 307 | if (copy_file(fname, buf, -1, file->mode) < 0) { |
| 308 | rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"", |
| 309 | full_fname(fname), buf); |
| 310 | unmake_file(file); |
| 311 | #ifdef SUPPORT_ACLS |
| 312 | uncache_tmp_acls(); |
| 313 | #endif |
| 314 | #ifdef SUPPORT_XATTRS |
| 315 | uncache_tmp_xattrs(); |
| 316 | #endif |
| 317 | return 0; |
| 318 | } |
| 319 | if (DEBUG_GTE(BACKUP, 1)) |
| 320 | rprintf(FINFO, "make_backup: COPY %s successful.\n", fname); |
| 321 | ret = 2; |
| 322 | } |
| 323 | |
| 324 | save_preserve_xattrs = preserve_xattrs; |
| 325 | preserve_xattrs = 0; |
| 326 | set_file_attrs(buf, file, NULL, fname, 0); |
| 327 | preserve_xattrs = save_preserve_xattrs; |
| 328 | |
| 329 | unmake_file(file); |
| 330 | #ifdef SUPPORT_ACLS |
| 331 | uncache_tmp_acls(); |
| 332 | #endif |
| 333 | #ifdef SUPPORT_XATTRS |
| 334 | uncache_tmp_xattrs(); |
| 335 | #endif |
| 336 | |
| 337 | success: |
| 338 | if (INFO_GTE(BACKUP, 1)) |
| 339 | rprintf(FINFO, "backed up %s to %s\n", fname, buf); |
| 340 | return ret; |
| 341 | } |