Adding more calls to safe_fname().
[rsync/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         char *fnamebak = get_backup_name(fname);
59
60         if (!fnamebak)
61                 return 0;
62
63         if (do_rename(fname, fnamebak) != 0) {
64                 /* cygwin (at least version b19) reports EINVAL */
65                 if (errno != ENOENT && errno != EINVAL) {
66                         rsyserr(FERROR, errno,
67                                 "rename %s to backup %s",
68                                 safe_fname(fname), safe_fname(fnamebak));
69                         return 0;
70                 }
71         } else if (verbose > 1) {
72                 rprintf(FINFO, "backed up %s to %s\n",
73                         safe_fname(fname), safe_fname(fnamebak));
74         }
75         return 1;
76 }
77
78
79 /****************************************************************************
80 Create a directory given an absolute path, perms based upon another directory
81 path
82 ****************************************************************************/
83 static int make_bak_dir(char *fullpath)
84 {
85         STRUCT_STAT st;
86         char *rel = fullpath + backup_dir_len;
87         char *end = rel + strlen(rel);
88         char *p = end;
89
90         while (strncmp(fullpath, "./", 2) == 0)
91                 fullpath += 2;
92
93         /* Try to find an existing dir, starting from the deepest dir. */
94         while (1) {
95                 if (--p == fullpath) {
96                         p += strlen(p);
97                         goto failure;
98                 }
99                 if (*p == '/') {
100                         *p = '\0';
101                         if (do_mkdir(fullpath, 0777 & ~orig_umask) == 0)
102                                 break;
103                         if (errno != ENOENT) {
104                                 rsyserr(FERROR, errno,
105                                         "make_bak_dir mkdir %s failed",
106                                         full_fname(fullpath));
107                                 goto failure;
108                         }
109                 }
110         }
111
112         /* Make all the dirs that we didn't find on the way here. */
113         while (1) {
114                 if (p >= rel) {
115                         /* Try to transfer the directory settings of the
116                          * actual dir that the files are coming from. */
117                         if (do_stat(rel, &st) < 0) {
118                                 rsyserr(FERROR, errno,
119                                         "make_bak_dir stat %s failed",
120                                         full_fname(rel));
121                         } else {
122                                 do_lchown(fullpath, st.st_uid, st.st_gid);
123                                 do_chmod(fullpath, st.st_mode);
124                         }
125                 }
126                 *p = '/';
127                 p += strlen(p);
128                 if (p == end)
129                         break;
130                 if (do_mkdir(fullpath, 0777 & ~orig_umask) < 0) {
131                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
132                                 full_fname(fullpath));
133                         goto failure;
134                 }
135         }
136         return 0;
137
138 failure:
139         while (p != end) {
140                 *p = '/';
141                 p += strlen(p);
142         }
143         return -1;
144 }
145
146 /* robustly move a file, creating new directory structures if necessary */
147 static int robust_move(char *src, char *dst)
148 {
149         if (robust_rename(src, dst, 0755) < 0 && (errno != ENOENT
150             || make_bak_dir(dst) < 0 || robust_rename(src, dst, 0755) < 0))
151                 return -1;
152         return 0;
153 }
154
155
156 /* If we have a --backup-dir, then we get here from make_backup().
157  * We will move the file to be deleted into a parallel directory tree. */
158 static int keep_backup(char *fname)
159 {
160         STRUCT_STAT st;
161         struct file_struct *file;
162         char *buf;
163         int kept = 0;
164         int ret_code;
165
166         /* return if no file to keep */
167         if (do_lstat(fname, &st) < 0)
168                 return 1;
169
170         if (!(file = make_file(fname, NULL, NO_FILTERS)))
171                 return 1; /* the file could have disappeared */
172
173         if (!(buf = get_backup_name(fname)))
174                 return 0;
175
176         /* Check to see if this is a device file, or link */
177         if (IS_DEVICE(file->mode)) {
178                 if (am_root && preserve_devices) {
179                         if (do_mknod(buf, file->mode, file->u.rdev) < 0
180                             && (errno != ENOENT || make_bak_dir(buf) < 0
181                              || do_mknod(buf, file->mode, file->u.rdev) < 0)) {
182                                 rsyserr(FERROR, errno, "mknod %s failed",
183                                         full_fname(buf));
184                         } else if (verbose > 2) {
185                                 rprintf(FINFO,
186                                         "make_backup: DEVICE %s successful.\n",
187                                         safe_fname(fname));
188                         }
189                 }
190                 kept = 1;
191                 do_unlink(fname);
192         }
193
194         if (!kept && S_ISDIR(file->mode)) {
195                 /* make an empty directory */
196                 if (do_mkdir(buf, file->mode) < 0
197                     && (errno != ENOENT || make_bak_dir(buf) < 0
198                      || do_mkdir(buf, file->mode) < 0)) {
199                         rsyserr(FINFO, errno, "mkdir %s failed",
200                                 full_fname(buf));
201                 }
202
203                 ret_code = do_rmdir(fname);
204                 if (verbose > 2) {
205                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
206                                 full_fname(fname), ret_code);
207                 }
208                 kept = 1;
209         }
210
211 #if SUPPORT_LINKS
212         if (!kept && preserve_links && S_ISLNK(file->mode)) {
213                 if (safe_symlinks && unsafe_symlink(file->u.link, buf)) {
214                         if (verbose) {
215                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
216                                         full_fname(buf), file->u.link);
217                         }
218                         kept = 1;
219                 }
220                 if (do_symlink(file->u.link, buf) < 0
221                     && (errno != ENOENT || make_bak_dir(buf) < 0
222                      || do_symlink(file->u.link, buf) < 0)) {
223                         rsyserr(FERROR, errno, "link %s -> \"%s\"",
224                                 full_fname(buf), safe_fname(file->u.link));
225                 }
226                 do_unlink(fname);
227                 kept = 1;
228         }
229 #endif
230
231         if (!kept && !S_ISREG(file->mode)) {
232                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
233                         safe_fname(fname));
234                 return 1;
235         }
236
237         /* move to keep tree if a file */
238         if (!kept) {
239                 if (robust_move(fname, buf) != 0) {
240                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
241                                 full_fname(fname), safe_fname(buf));
242                 } else if (st.st_nlink > 1) {
243                         /* If someone has hard-linked the file into the backup
244                          * dir, rename() might return success but do nothing! */
245                         robust_unlink(fname); /* Just in case... */
246                 }
247         }
248         set_perms(buf, file, NULL, 0);
249         free(file);
250
251         if (verbose > 1) {
252                 rprintf(FINFO, "backed up %s to %s\n",
253                         safe_fname(fname), safe_fname(buf));
254         }
255         return 1;
256 }
257
258
259 /* main backup switch routine */
260 int make_backup(char *fname)
261 {
262         if (backup_dir)
263                 return keep_backup(fname);
264         return make_simple_backup(fname);
265 }