preparing for release of 2.5.7
[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 char *backup_suffix;
27 extern char *backup_dir;
28
29 extern int am_root;
30 extern int preserve_devices;
31 extern int preserve_links;
32 extern int preserve_hard_links;
33
34 /* simple backup creates a backup with a suffix in the same directory */
35 static int make_simple_backup(char *fname)
36 {
37         char fnamebak[MAXPATHLEN];
38         if (strlen(fname) + backup_suffix_len > MAXPATHLEN-1) {
39                 rprintf(FERROR, "backup filename too long\n");
40                 return 0;
41         }
42
43         snprintf(fnamebak, sizeof(fnamebak), "%s%s", fname, backup_suffix);
44         if (do_rename(fname, fnamebak) != 0) {
45                 /* cygwin (at least version b19) reports EINVAL */
46                 if (errno != ENOENT && errno != EINVAL) {
47                         rsyserr(FERROR, errno, "rename %s to backup %s", fname, fnamebak);
48                         return 0;
49                 }
50         } else if (verbose > 1) {
51                 rprintf(FINFO, "backed up %s to %s\n", fname, fnamebak);
52         }
53         return 1;
54 }
55
56
57 /* recursively make a directory path */
58 static int make_dir(char *name, int mask)
59 {
60         char newdir [MAXPATHLEN];
61         char *p, *d;
62
63         /* copy pathname over, look for last '/' */
64         for (p = d = newdir; *name; *d++ = *name++)
65                 if (*name == '/')
66                         p = d;
67         if (p == newdir)
68                 return 0;
69         *p = 0;
70
71         /* make the new directory, if that fails then make its parent */
72         while (do_mkdir (newdir, mask) != 0)
73                 if ((errno != ENOENT) || !make_dir (newdir, mask))
74                         return 0;
75
76         return 1;
77 } /* make_dir */
78
79
80 /****************************************************************************
81 Create a directory given an absolute path, perms based upon another directory
82 path
83 ****************************************************************************/
84 static int make_bak_dir(char *fname, char *bak_path)
85 {
86         STRUCT_STAT st;
87         STRUCT_STAT *st2;
88         char fullpath[MAXPATHLEN];
89         extern int orig_umask;
90         char *p;
91         char *q;
92
93         while(strncmp(bak_path, "./", 2) == 0) bak_path += 2;
94
95         if(bak_path[strlen(bak_path)-1] != '/') {
96                 snprintf(fullpath, sizeof(fullpath), "%s/", bak_path);
97         } else {
98                 snprintf(fullpath, sizeof(fullpath), "%s", bak_path);
99         }
100         p = fullpath;
101         q = &fullpath[strlen(fullpath)];  /* End of bak_path string */
102         strcat(fullpath, fname);
103
104         /* Make the directories */
105         while ((p = strchr(p, '/'))) {
106                 *p = 0;
107                 if(do_lstat(fullpath, &st) != 0) {
108                         do_mkdir(fullpath, 0777 & ~orig_umask);
109                         if(p>q) {
110                                 if(do_lstat(q, &st) != 0) {
111                                         rprintf(FERROR, "make_bak_dir stat %s failed: %s\n",
112                                                 full_fname(fullpath), strerror(errno));
113                                 } else {
114                                         st2 = &st;
115                                         set_modtime(fullpath, st2->st_mtime);
116                                         if(do_lchown(fullpath, st2->st_uid, st2->st_gid) != 0) {
117                                                 rprintf(FERROR, "make_bak_dir chown %s failed: %s\n",
118                                                         full_fname(fullpath), strerror(errno));
119                                         }
120                                         if(do_chmod(fullpath, st2->st_mode) != 0) {
121                                                 rprintf(FERROR, "make_bak_dir failed to set permissions on %s: %s\n",
122                                                         full_fname(fullpath), strerror(errno));
123                                         }
124                                 }
125                         }
126                 }
127                 *p = '/';
128                 p++;
129         }
130         return 0;
131 }
132
133 /* robustly move a file, creating new directory structures if necessary */
134 static int robust_move(char *src, char *dst)
135 {
136         int keep_trying = 4;
137         int keep_path_extfs = 0;
138         int failed;
139
140         while (keep_trying) {
141                 if (keep_path_extfs) {
142                         failed = copy_file(src, dst, 0755);
143                         if (!failed) {
144                                 do_unlink(src);
145                         }
146                 } else {
147                         failed = robust_rename (src, dst);
148                 }
149
150                 if (failed) {
151                         if (verbose > 2)
152                                 rprintf (FERROR, "robust_move failed: %s(%d)\n",
153                                     strerror (errno), errno);
154                         switch (errno) {
155                                 /* external filesystem */
156                                 case EXDEV:
157                                         keep_path_extfs = 1;
158                                         keep_trying--;
159                                         break;
160                                 /* no directory to write to */
161                                 case ENOENT:
162                                         make_dir(dst, 0700);
163                                         keep_trying--;
164                                         break;
165                                 default:
166                                         keep_trying = 0;
167                         } /* switch */
168                 } else
169                         keep_trying = 0;
170         } /* while */
171         return (!failed);
172 } /* robust_move */
173
174
175 /* if we have a backup_dir, then we get here from make_backup().
176    We will move the file to be deleted into a parallel directory tree */
177 static int keep_backup(char *fname)
178 {
179
180         static int initialised;
181
182         char keep_name [MAXPATHLEN];
183         STRUCT_STAT st;
184         struct file_struct *file;
185
186         int kept = 0;
187         int ret_code;
188
189         if (!initialised) {
190                 if (backup_dir_len && backup_dir[backup_dir_len - 1] == '/')
191                         backup_dir[--backup_dir_len] = '\0';
192                 if (verbose > 0)
193                         rprintf (FINFO, "backup_dir is %s\n", backup_dir);
194                 initialised = 1;
195         }
196
197         /* return if no file to keep */
198 #if SUPPORT_LINKS
199         if (do_lstat (fname, &st)) return 1;
200 #else
201         if (do_stat (fname, &st)) return 1;
202 #endif
203
204         file = make_file(fname, NULL, NO_EXCLUDES);
205
206         /* the file could have disappeared */
207         if (!file) return 1;
208
209         /* make a complete pathname for backup file */
210         if (backup_dir_len+strlen(fname)+backup_suffix_len > MAXPATHLEN-1) {
211                 rprintf (FERROR, "keep_backup filename too long\n");
212                 return 0;
213         }
214
215         snprintf(keep_name, sizeof (keep_name), "%s/%s%s",
216             backup_dir, fname, backup_suffix);
217
218 #ifdef HAVE_MKNOD
219         /* Check to see if this is a device file, or link */
220         if(IS_DEVICE(file->mode)) {
221                 if(am_root && preserve_devices) {
222                         make_bak_dir(fname, backup_dir);
223                         if(do_mknod(keep_name, file->mode, file->rdev) != 0) {
224                                 rprintf(FERROR, "mknod %s failed: %s\n",
225                                         full_fname(keep_name), strerror(errno));
226                         } else if(verbose>2) {
227                                 rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
228                         }
229                 }
230                 kept = 1;
231                 do_unlink(fname);
232         }
233 #endif
234
235         if(!kept && S_ISDIR(file->mode)) {
236                 /* make an empty directory */
237                 make_bak_dir(fname, backup_dir);
238                 do_mkdir(keep_name, file->mode);
239                 ret_code = do_rmdir(fname);
240
241                 if(verbose>2) {
242                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
243                                 full_fname(fname), ret_code);
244                 }
245                 kept = 1;
246         }
247
248 #if SUPPORT_LINKS
249         if(!kept && preserve_links && S_ISLNK(file->mode)) {
250                 extern int safe_symlinks;
251                 if (safe_symlinks && unsafe_symlink(file->link, keep_name)) {
252                         if (verbose) {
253                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
254                                         full_fname(keep_name), file->link);
255                         }
256                         kept = 1;
257                 }
258                 make_bak_dir(fname, backup_dir);
259                 if(do_symlink(file->link, keep_name) != 0) {
260                         rprintf(FERROR, "link %s -> %s : %s\n",
261                                 full_fname(keep_name), file->link, strerror(errno));
262                 }
263                 do_unlink(fname);
264                 kept = 1;
265         }
266 #endif
267         if(!kept && preserve_hard_links && check_hard_link(file)) {
268                 if(verbose > 1)
269                         rprintf(FINFO, "%s is a hard link\n", f_name(file));
270         }
271
272         if(!kept && !S_ISREG(file->mode)) {
273                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
274                     fname);
275         }
276
277         /* move to keep tree if a file */
278         if(!kept) {
279                 if (!robust_move (fname, keep_name)) {
280                         rprintf(FERROR, "keep_backup failed: %s -> \"%s\": %s\n",
281                                 full_fname(fname), keep_name, strerror(errno));
282                 }
283         }
284         set_perms (keep_name, file, NULL, 0);
285         free_file (file);
286         free (file);
287
288         if (verbose > 1)
289                 rprintf (FINFO, "keep_backup %s -> %s\n", fname, keep_name);
290         return 1;
291 } /* keep_backup */
292
293
294 /* main backup switch routine */
295 int make_backup(char *fname)
296 {
297         if (backup_dir)
298                 return (keep_backup(fname));
299         else
300                 return (make_simple_backup(fname));
301 }