- Added set_io_timeout(), which sets all the timeout-dependent
[rsync.git] / backup.c
1 /*
2    Copyright (C) Andrew Tridgell 1999
3
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 2 of the License, or
7    (at your option) any later version.
8
9    This program is distributed in the hope that it will be useful,
10    but WITHOUT ANY WARRANTY; without even the implied warranty of
11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12    GNU General Public License for more details.
13
14    You should have received a copy of the GNU General Public License
15    along with this program; if not, write to the Free Software
16    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 /* backup handling code */
20
21 #include "rsync.h"
22
23 extern int verbose;
24 extern int backup_suffix_len;
25 extern int backup_dir_len;
26 extern unsigned int backup_dir_remainder;
27 extern char backup_dir_buf[MAXPATHLEN];
28 extern char *backup_suffix;
29 extern char *backup_dir;
30
31 extern int am_root;
32 extern int preserve_devices;
33 extern int preserve_links;
34 extern int preserve_hard_links;
35 extern int orig_umask;
36 extern int safe_symlinks;
37
38 /* make a complete pathname for backup file */
39 char *get_backup_name(char *fname)
40 {
41         if (backup_dir) {
42                 if (stringjoin(backup_dir_buf + backup_dir_len, backup_dir_remainder,
43                                fname, backup_suffix, NULL) < backup_dir_remainder)
44                         return backup_dir_buf;
45         } else {
46                 if (stringjoin(backup_dir_buf, MAXPATHLEN,
47                                fname, backup_suffix, NULL) < MAXPATHLEN)
48                         return backup_dir_buf;
49         }
50
51         rprintf(FERROR, "backup filename too long\n");
52         return NULL;
53 }
54
55 /* simple backup creates a backup with a suffix in the same directory */
56 static int make_simple_backup(char *fname)
57 {
58         int rename_errno;
59         char *fnamebak = get_backup_name(fname);
60
61         if (!fnamebak)
62                 return 0;
63
64         while (1) {
65                 if (do_rename(fname, fnamebak) == 0) {
66                         if (verbose > 1) {
67                                 rprintf(FINFO, "backed up %s to %s\n",
68                                         safe_fname(fname),
69                                         safe_fname(fnamebak));
70                         }
71                         break;
72                 }
73                 /* cygwin (at least version b19) reports EINVAL */
74                 if (errno == ENOENT || errno == EINVAL)
75                         break;
76
77                 rename_errno = errno;
78                 if (errno == EISDIR && do_rmdir(fnamebak) == 0)
79                         continue;
80                 if (errno == ENOTDIR && do_unlink(fnamebak) == 0)
81                         continue;
82
83                 rsyserr(FERROR, rename_errno, "rename %s to backup %s",
84                         safe_fname(fname), safe_fname(fnamebak));
85                 errno = rename_errno;
86                 return 0;
87         }
88
89         return 1;
90 }
91
92
93 /****************************************************************************
94 Create a directory given an absolute path, perms based upon another directory
95 path
96 ****************************************************************************/
97 static int make_bak_dir(char *fullpath)
98 {
99         STRUCT_STAT st;
100         char *rel = fullpath + backup_dir_len;
101         char *end = rel + strlen(rel);
102         char *p = end;
103
104         while (strncmp(fullpath, "./", 2) == 0)
105                 fullpath += 2;
106
107         /* Try to find an existing dir, starting from the deepest dir. */
108         while (1) {
109                 if (--p == fullpath) {
110                         p += strlen(p);
111                         goto failure;
112                 }
113                 if (*p == '/') {
114                         *p = '\0';
115                         if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
116                                 break;
117                         if (errno != ENOENT) {
118                                 rsyserr(FERROR, errno,
119                                         "make_bak_dir mkdir %s failed",
120                                         full_fname(fullpath));
121                                 goto failure;
122                         }
123                 }
124         }
125
126         /* Make all the dirs that we didn't find on the way here. */
127         while (1) {
128                 if (p >= rel) {
129                         /* Try to transfer the directory settings of the
130                          * actual dir that the files are coming from. */
131                         if (do_stat(rel, &st) < 0) {
132                                 rsyserr(FERROR, errno,
133                                         "make_bak_dir stat %s failed",
134                                         full_fname(rel));
135                         } else {
136                                 do_lchown(fullpath, st.st_uid, st.st_gid);
137                                 do_chmod(fullpath, st.st_mode);
138                         }
139                 }
140                 *p = '/';
141                 p += strlen(p);
142                 if (p == end)
143                         break;
144                 if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
145                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
146                                 full_fname(fullpath));
147                         goto failure;
148                 }
149         }
150         return 0;
151
152 failure:
153         while (p != end) {
154                 *p = '/';
155                 p += strlen(p);
156         }
157         return -1;
158 }
159
160 /* robustly move a file, creating new directory structures if necessary */
161 static int robust_move(char *src, char *dst)
162 {
163         if (robust_rename(src, dst, 0755) < 0 && (errno != ENOENT
164             || make_bak_dir(dst) < 0 || robust_rename(src, dst, 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(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, NO_FILTERS)))
185                 return 1; /* the file could have disappeared */
186
187         if (!(buf = get_backup_name(fname)))
188                 return 0;
189
190         /* Check to see if this is a device file, or link */
191         if (IS_DEVICE(file->mode)) {
192                 if (am_root && preserve_devices) {
193                         if (do_mknod(buf, file->mode, file->u.rdev) < 0
194                             && (errno != ENOENT || make_bak_dir(buf) < 0
195                              || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
196                                 rsyserr(FERROR, errno, "mknod %s failed",
197                                         full_fname(buf));
198                         } else if (verbose > 2) {
199                                 rprintf(FINFO,
200                                         "make_backup: DEVICE %s successful.\n",
201                                         safe_fname(fname));
202                         }
203                 }
204                 kept = 1;
205                 do_unlink(fname);
206         }
207
208         if (!kept && S_ISDIR(file->mode)) {
209                 /* make an empty directory */
210                 if (do_mkdir(buf, file->mode) < 0
211                     && (errno != ENOENT || make_bak_dir(buf) < 0
212                      || do_mkdir(buf, file->mode) < 0)) {
213                         rsyserr(FINFO, errno, "mkdir %s failed",
214                                 full_fname(buf));
215                 }
216
217                 ret_code = do_rmdir(fname);
218                 if (verbose > 2) {
219                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
220                                 full_fname(fname), ret_code);
221                 }
222                 kept = 1;
223         }
224
225 #ifdef SUPPORT_LINKS
226         if (!kept && preserve_links && S_ISLNK(file->mode)) {
227                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
228                         if (verbose) {
229                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
230                                         full_fname(buf), file->u.link);
231                         }
232                         kept = 1;
233                 }
234                 if (do_symlink(file->u.link, buf) < 0
235                     && (errno != ENOENT || make_bak_dir(buf) < 0
236                      || do_symlink(file->u.link, buf) < 0)) {
237                         rsyserr(FERROR, errno, "link %s -> \"%s\"",
238                                 full_fname(buf), safe_fname(file->u.link));
239                 }
240                 do_unlink(fname);
241                 kept = 1;
242         }
243 #endif
244
245         if (!kept && !S_ISREG(file->mode)) {
246                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
247                         safe_fname(fname));
248                 return 1;
249         }
250
251         /* move to keep tree if a file */
252         if (!kept) {
253                 if (robust_move(fname, buf) != 0) {
254                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
255                                 full_fname(fname), safe_fname(buf));
256                 } else if (st.st_nlink > 1) {
257                         /* If someone has hard-linked the file into the backup
258                          * dir, rename() might return success but do nothing! */
259                         robust_unlink(fname); /* Just in case... */
260                 }
261         }
262         set_perms(buf, file, NULL, 0);
263         free(file);
264
265         if (verbose > 1) {
266                 rprintf(FINFO, "backed up %s to %s\n",
267                         safe_fname(fname), safe_fname(buf));
268         }
269         return 1;
270 }
271
272
273 /* main backup switch routine */
274 int make_backup(char *fname)
275 {
276         if (backup_dir)
277                 return keep_backup(fname);
278         return make_simple_backup(fname);
279 }