2 * Backup handling code.
4 * Copyright (C) 1999 Andrew Tridgell
5 * Copyright (C) 2003-2022 Wayne Davison
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.
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.
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.
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;
37 /* Returns -1 on error, 0 on missing dir, and 1 on present dir. */
38 static int validate_backup_dir(void)
42 if (do_lstat(backup_dir_buf, &st) < 0) {
45 rsyserr(FERROR, errno, "backup lstat %s failed", backup_dir_buf);
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)
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)
67 char *b, *rel = backup_dir_buf + backup_dir_len, *name = rel;
69 for (f = fname, b = rel; *f && *f == *b; f++, b++) {
74 if (stringjoin(rel, backup_dir_remainder, fname, backup_suffix, NULL) >= backup_dir_remainder) {
75 rprintf(FERROR, "backup filename too long\n");
80 for ( ; ; name = b + 1) {
81 if ((b = strchr(name, '/')) == NULL)
85 val = validate_backup_dir();
98 for ( ; b; name = b + 1, b = strchr(name, '/')) {
101 while (do_mkdir(backup_dir_buf, ACCESSPERMS) < 0) {
102 if (errno == EEXIST) {
103 val = validate_backup_dir();
109 rsyserr(FERROR, errno, "backup mkdir %s failed", backup_dir_buf);
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));
120 struct file_struct *file;
121 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
124 if (preserve_acls && !S_ISLNK(file->mode)) {
126 cache_tmp_acl(file, &sx);
130 #ifdef SUPPORT_XATTRS
131 if (preserve_xattrs) {
133 cache_tmp_xattr(file, &sx);
137 set_file_attrs(backup_dir_buf, file, NULL, NULL, 0);
149 #ifdef SUPPORT_XATTRS
150 uncache_tmp_xattrs();
156 /* Make a complete pathname for backup file and verify any new path elements. */
157 char *get_backup_name(const char *fname)
160 static int initialized = 0;
163 if (backup_dir_len > 1)
164 backup_dir_buf[backup_dir_len-1] = '\0';
165 ret = make_path(backup_dir_buf, 0);
166 if (backup_dir_len > 1)
167 backup_dir_buf[backup_dir_len-1] = '/';
172 /* copy fname into backup_dir_buf while validating the dirs. */
173 if (copy_valid_path(fname))
174 return backup_dir_buf;
175 /* copy_valid_path() has printed an error message. */
179 if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
180 return backup_dir_buf;
182 rprintf(FERROR, "backup filename too long\n");
186 /* Has same return codes as make_backup(). */
187 static inline int link_or_rename(const char *from, const char *to,
188 BOOL prefer_rename, STRUCT_STAT *stp)
190 #ifdef SUPPORT_HARD_LINKS
191 if (!prefer_rename) {
192 #ifndef CAN_HARDLINK_SYMLINK
193 if (S_ISLNK(stp->st_mode))
194 return 0; /* Use copy code. */
196 #ifndef CAN_HARDLINK_SPECIAL
197 if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode))
198 return 0; /* Use copy code. */
200 if (do_link(from, to) == 0) {
201 if (DEBUG_GTE(BACKUP, 1))
202 rprintf(FINFO, "make_backup: HLINK %s successful.\n", from);
205 /* We prefer to rename a regular file rather than copy it. */
206 if (!S_ISREG(stp->st_mode) || errno == EEXIST || errno == EISDIR)
210 if (do_rename(from, to) == 0) {
211 if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) {
212 /* If someone has hard-linked the file into the backup
213 * dir, rename() might return success but do nothing! */
214 robust_unlink(from); /* Just in case... */
216 if (DEBUG_GTE(BACKUP, 1))
217 rprintf(FINFO, "make_backup: RENAME %s successful.\n", from);
223 /* Hard-link, rename, or copy an item to the backup name. Returns 0 for
224 * failure, 1 if item was moved, 2 if item was duplicated or hard linked
225 * into backup area, or 3 if item doesn't exist or isn't a regular file. */
226 int make_backup(const char *fname, BOOL prefer_rename)
229 struct file_struct *file;
230 int save_preserve_xattrs;
235 /* Return success if no file to keep. */
236 if (x_lstat(fname, &sx.st, NULL) < 0)
239 if (!(buf = get_backup_name(fname)))
242 /* Try a hard-link or a rename first. Using rename is not atomic, but
243 * is more efficient than forcing a copy for larger files when no hard-
244 * linking is possible. */
245 if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
247 if (errno == EEXIST || errno == EISDIR) {
249 if (do_lstat(buf, &bakst) == 0) {
250 int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
251 if (delete_item(buf, bakst.st_mode, flags) != 0)
254 if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
258 /* Fall back to making a copy. */
259 if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
260 return 3; /* the file could have disappeared */
263 if (preserve_acls && !S_ISLNK(file->mode)) {
265 cache_tmp_acl(file, &sx);
269 #ifdef SUPPORT_XATTRS
270 if (preserve_xattrs) {
271 get_xattr(fname, &sx);
272 cache_tmp_xattr(file, &sx);
277 /* Check to see if this is a device file, or link */
278 if ((am_root && preserve_devices && IS_DEVICE(file->mode))
279 || (preserve_specials && IS_SPECIAL(file->mode))) {
280 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
281 rsyserr(FERROR, errno, "mknod %s failed", full_fname(buf));
282 else if (DEBUG_GTE(BACKUP, 1))
283 rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
288 if (!ret && preserve_links && S_ISLNK(file->mode)) {
289 const char *sl = F_SYMLINK(file);
290 if (safe_symlinks && unsafe_symlink(sl, fname)) {
291 if (INFO_GTE(SYMSAFE, 1)) {
292 rprintf(FINFO, "not backing up unsafe symlink \"%s\" -> \"%s\"\n",
297 if (do_symlink(sl, buf) < 0)
298 rsyserr(FERROR, errno, "link %s -> \"%s\"", full_fname(buf), sl);
299 else if (DEBUG_GTE(BACKUP, 1))
300 rprintf(FINFO, "make_backup: SYMLINK %s successful.\n", fname);
306 if (!ret && !S_ISREG(file->mode)) {
307 if (INFO_GTE(NONREG, 1))
308 rprintf(FINFO, "make_bak: skipping non-regular file %s\n", fname);
313 #ifdef SUPPORT_XATTRS
314 uncache_tmp_xattrs();
319 /* Copy to backup tree if a file. */
321 if (copy_file(fname, buf, -1, file->mode) < 0) {
322 rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
323 full_fname(fname), buf);
328 #ifdef SUPPORT_XATTRS
329 uncache_tmp_xattrs();
333 if (DEBUG_GTE(BACKUP, 1))
334 rprintf(FINFO, "make_backup: COPY %s successful.\n", fname);
338 save_preserve_xattrs = preserve_xattrs;
340 set_file_attrs(buf, file, NULL, fname, ATTRS_ACCURATE_TIME);
341 preserve_xattrs = save_preserve_xattrs;
347 #ifdef SUPPORT_XATTRS
348 uncache_tmp_xattrs();
352 if (INFO_GTE(BACKUP, 1))
353 rprintf(FINFO, "backed up %s to %s\n", fname, buf);