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