Fixed a thinko and a typo in the --append option.
[rsync.git] / backup.c
1 /*
2  * Backup handling code.
3  *
4  * Copyright (C) 1999 Andrew Tridgell
5  * Copyright (C) 2003-2008 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
23 extern int verbose;
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 /* make a complete pathname for backup file */
38 char *get_backup_name(const char *fname)
39 {
40         if (backup_dir) {
41                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
42                                fname, backup_suffix, NULL) < backup_dir_remainder)
43                         return backup_dir_buf;
44         } else {
45                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
46                                fname, backup_suffix, NULL) < MAXPATHLEN)
47                         return backup_dir_buf;
48         }
49
50         rprintf(FERROR, "backup filename too long\n");
51         return NULL;
52 }
53
54 /* simple backup creates a backup with a suffix in the same directory */
55 static int make_simple_backup(const char *fname)
56 {
57         int rename_errno;
58         const char *fnamebak = get_backup_name(fname);
59
60         if (!fnamebak)
61                 return 0;
62
63         while (1) {
64                 if (do_rename(fname, fnamebak) == 0) {
65                         if (verbose > 1) {
66                                 rprintf(FINFO, "backed up %s to %s\n",
67                                         fname, fnamebak);
68                         }
69                         break;
70                 }
71                 /* cygwin (at least version b19) reports EINVAL */
72                 if (errno == ENOENT || errno == EINVAL)
73                         break;
74
75                 rename_errno = errno;
76                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
77                         continue;
78                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
79                         continue;
80
81                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
82                         fname, fnamebak);
83                 errno = rename_errno;
84                 return 0;
85         }
86
87         return 1;
88 }
89
90
91 /****************************************************************************
92 Create a directory given an absolute path, perms based upon another directory
93 path
94 ****************************************************************************/
95 int make_bak_dir(const char *fullpath)
96 {
97         char fbuf[MAXPATHLEN], *rel, *end, *p;
98         struct file_struct *file;
99         int len = backup_dir_len;
100         stat_x sx;
101
102         while (*fullpath == '.' && fullpath[1] == '/') {
103                 fullpath += 2;
104                 len -= 2;
105         }
106
107         if (strlcpy(fbuf, fullpath, sizeof fbuf) >= sizeof fbuf)
108                 return -1;
109
110         rel = fbuf + len;
111         end = p = rel + strlen(rel);
112
113         /* Try to find an existing dir, starting from the deepest dir. */
114         while (1) {
115                 if (--p == fbuf)
116                         return -1;
117                 if (*p == '/') {
118                         *p = '\0';
119                         if (mkdir_defmode(fbuf) == 0)
120                                 break;
121                         if (errno != ENOENT) {
122                                 rsyserr(FERROR, errno,
123                                         "make_bak_dir mkdir %s failed",
124                                         full_fname(fbuf));
125                                 return -1;
126                         }
127                 }
128         }
129
130         /* Make all the dirs that we didn't find on the way here. */
131         while (1) {
132                 if (p >= rel) {
133                         /* Try to transfer the directory settings of the
134                          * actual dir that the files are coming from. */
135                         if (x_stat(rel, &sx.st, NULL) < 0) {
136                                 rsyserr(FERROR, errno,
137                                         "make_bak_dir stat %s failed",
138                                         full_fname(rel));
139                         } else {
140 #ifdef SUPPORT_ACLS
141                                 sx.acc_acl = sx.def_acl = NULL;
142 #endif
143 #ifdef SUPPORT_XATTRS
144                                 sx.xattr = NULL;
145 #endif
146                                 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
147                                         continue;
148 #ifdef SUPPORT_ACLS
149                                 if (preserve_acls && !S_ISLNK(file->mode)) {
150                                         get_acl(rel, &sx);
151                                         cache_acl(file, &sx);
152                                         free_acl(&sx);
153                                 }
154 #endif
155 #ifdef SUPPORT_XATTRS
156                                 if (preserve_xattrs) {
157                                         get_xattr(rel, &sx);
158                                         cache_xattr(file, &sx);
159                                         free_xattr(&sx);
160                                 }
161 #endif
162                                 set_file_attrs(fbuf, file, NULL, NULL, 0);
163                                 unmake_file(file);
164                         }
165                 }
166                 *p = '/';
167                 p += strlen(p);
168                 if (p == end)
169                         break;
170                 if (mkdir_defmode(fbuf) < 0) {
171                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
172                                 full_fname(fbuf));
173                         return -1;
174                 }
175         }
176
177         return 0;
178 }
179
180 /* robustly move a file, creating new directory structures if necessary */
181 static int robust_move(const char *src, char *dst)
182 {
183         if (robust_rename(src, dst, NULL, 0755) < 0
184          && (errno != ENOENT || make_bak_dir(dst) < 0
185           || robust_rename(src, dst, NULL, 0755) < 0))
186                 return -1;
187         return 0;
188 }
189
190
191 /* If we have a --backup-dir, then we get here from make_backup().
192  * We will move the file to be deleted into a parallel directory tree. */
193 static int keep_backup(const char *fname)
194 {
195         stat_x sx;
196         struct file_struct *file;
197         char *buf;
198         int kept = 0;
199         int ret_code;
200
201         /* return if no file to keep */
202         if (x_lstat(fname, &sx.st, NULL) < 0)
203                 return 1;
204 #ifdef SUPPORT_ACLS
205         sx.acc_acl = sx.def_acl = NULL;
206 #endif
207 #ifdef SUPPORT_XATTRS
208         sx.xattr = NULL;
209 #endif
210
211         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
212                 return 1; /* the file could have disappeared */
213
214         if (!(buf = get_backup_name(fname))) {
215                 unmake_file(file);
216                 return 0;
217         }
218
219 #ifdef SUPPORT_ACLS
220         if (preserve_acls && !S_ISLNK(file->mode)) {
221                 get_acl(fname, &sx);
222                 cache_acl(file, &sx);
223                 free_acl(&sx);
224         }
225 #endif
226 #ifdef SUPPORT_XATTRS
227         if (preserve_xattrs) {
228                 get_xattr(fname, &sx);
229                 cache_xattr(file, &sx);
230                 free_xattr(&sx);
231         }
232 #endif
233
234         /* Check to see if this is a device file, or link */
235         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
236          || (preserve_specials && IS_SPECIAL(file->mode))) {
237                 uint32 *devp = F_RDEV_P(file);
238                 dev_t rdev = MAKEDEV(DEV_MAJOR(devp), DEV_MINOR(devp));
239                 do_unlink(buf);
240                 if (do_mknod(buf, file->mode, rdev) < 0
241                     && (errno != ENOENT || make_bak_dir(buf) < 0
242                      || do_mknod(buf, file->mode, rdev) < 0)) {
243                         rsyserr(FERROR, errno, "mknod %s failed",
244                                 full_fname(buf));
245                 } else if (verbose > 2) {
246                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
247                                 fname);
248                 }
249                 kept = 1;
250                 do_unlink(fname);
251         }
252
253         if (!kept && S_ISDIR(file->mode)) {
254                 /* make an empty directory */
255                 if (do_mkdir(buf, file->mode) < 0
256                     && (errno != ENOENT || make_bak_dir(buf) < 0
257                      || do_mkdir(buf, file->mode) < 0)) {
258                         rsyserr(FINFO, errno, "mkdir %s failed",
259                                 full_fname(buf));
260                 }
261
262                 ret_code = do_rmdir(fname);
263                 if (verbose > 2) {
264                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
265                                 full_fname(fname), ret_code);
266                 }
267                 kept = 1;
268         }
269
270 #ifdef SUPPORT_LINKS
271         if (!kept && preserve_links && S_ISLNK(file->mode)) {
272                 const char *sl = F_SYMLINK(file);
273                 if (safe_symlinks && unsafe_symlink(sl, buf)) {
274                         if (verbose) {
275                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
276                                         full_fname(buf), sl);
277                         }
278                         kept = 1;
279                 } else {
280                         do_unlink(buf);
281                         if (do_symlink(sl, buf) < 0
282                             && (errno != ENOENT || make_bak_dir(buf) < 0
283                              || do_symlink(sl, buf) < 0)) {
284                                 rsyserr(FERROR, errno, "link %s -> \"%s\"",
285                                         full_fname(buf), sl);
286                         }
287                         do_unlink(fname);
288                         kept = 1;
289                 }
290         }
291 #endif
292
293         if (!kept && !S_ISREG(file->mode)) {
294                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
295                         fname);
296                 unmake_file(file);
297                 return 1;
298         }
299
300         /* move to keep tree if a file */
301         if (!kept) {
302                 if (robust_move(fname, buf) != 0) {
303                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
304                                 full_fname(fname), buf);
305                 } else if (sx.st.st_nlink > 1) {
306                         /* If someone has hard-linked the file into the backup
307                          * dir, rename() might return success but do nothing! */
308                         robust_unlink(fname); /* Just in case... */
309                 }
310         }
311         set_file_attrs(buf, file, NULL, fname, 0);
312         unmake_file(file);
313
314         if (verbose > 1) {
315                 rprintf(FINFO, "backed up %s to %s\n",
316                         fname, buf);
317         }
318         return 1;
319 }
320
321
322 /* main backup switch routine */
323 int make_backup(const char *fname)
324 {
325         if (backup_dir)
326                 return keep_backup(fname);
327         return make_simple_backup(fname);
328 }