Ensure that the generator gets notified about an I/O error for the dir
[rsync.git] / backup.c
1 /*
2  * Backup handling code.
3  *
4  * Copyright (C) 1999 Andrew Tridgell
5  * Copyright (C) 2003-2009 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_tmp_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_tmp_xattr(file, &sx);
159                                         free_xattr(&sx);
160                                 }
161 #endif
162                                 set_file_attrs(fbuf, file, NULL, NULL, 0);
163                                 unmake_file(file);
164 #ifdef SUPPORT_ACLS
165                                 uncache_tmp_acls();
166 #endif
167 #ifdef SUPPORT_XATTRS
168                                 uncache_tmp_xattrs();
169 #endif
170                         }
171                 }
172                 *p = '/';
173                 p += strlen(p);
174                 if (p == end)
175                         break;
176                 if (mkdir_defmode(fbuf) < 0) {
177                         rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
178                                 full_fname(fbuf));
179                         return -1;
180                 }
181         }
182
183         return 0;
184 }
185
186 /* robustly move a file, creating new directory structures if necessary */
187 static int robust_move(const char *src, char *dst)
188 {
189         if (robust_rename(src, dst, NULL, 0755) < 0) {
190                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
191                 if (errno == ENOENT && make_bak_dir(dst) == 0) {
192                         if (robust_rename(src, dst, NULL, 0755) < 0)
193                                 save_errno = errno ? errno : save_errno;
194                         else
195                                 save_errno = 0;
196                 }
197                 if (save_errno) {
198                         errno = save_errno;
199                         return -1;
200                 }
201         }
202         return 0;
203 }
204
205
206 /* If we have a --backup-dir, then we get here from make_backup().
207  * We will move the file to be deleted into a parallel directory tree. */
208 static int keep_backup(const char *fname)
209 {
210         stat_x sx;
211         struct file_struct *file;
212         char *buf;
213         int save_preserve_xattrs = preserve_xattrs;
214         int kept = 0;
215         int ret_code;
216
217         /* return if no file to keep */
218         if (x_lstat(fname, &sx.st, NULL) < 0)
219                 return 1;
220 #ifdef SUPPORT_ACLS
221         sx.acc_acl = sx.def_acl = NULL;
222 #endif
223 #ifdef SUPPORT_XATTRS
224         sx.xattr = NULL;
225 #endif
226
227         if (!(file = make_file(fname, NULL, NULL, 0, NO_FILTERS)))
228                 return 1; /* the file could have disappeared */
229
230         if (!(buf = get_backup_name(fname))) {
231                 unmake_file(file);
232 #ifdef SUPPORT_ACLS
233                 uncache_tmp_acls();
234 #endif
235 #ifdef SUPPORT_XATTRS
236                 uncache_tmp_xattrs();
237 #endif
238                 return 0;
239         }
240
241 #ifdef SUPPORT_ACLS
242         if (preserve_acls && !S_ISLNK(file->mode)) {
243                 get_acl(fname, &sx);
244                 cache_tmp_acl(file, &sx);
245                 free_acl(&sx);
246         }
247 #endif
248 #ifdef SUPPORT_XATTRS
249         if (preserve_xattrs) {
250                 get_xattr(fname, &sx);
251                 cache_tmp_xattr(file, &sx);
252                 free_xattr(&sx);
253         }
254 #endif
255
256         /* Check to see if this is a device file, or link */
257         if ((am_root && preserve_devices && IS_DEVICE(file->mode))
258          || (preserve_specials && IS_SPECIAL(file->mode))) {
259                 int save_errno;
260                 do_unlink(buf);
261                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0) {
262                         save_errno = errno ? errno : EINVAL; /* 0 paranoia */
263                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
264                                 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
265                                         save_errno = errno ? errno : save_errno;
266                                 else
267                                         save_errno = 0;
268                         }
269                         if (save_errno) {
270                                 rsyserr(FERROR, save_errno, "mknod %s failed",
271                                         full_fname(buf));
272                         }
273                 } else
274                         save_errno = 0;
275                 if (verbose > 2 && save_errno == 0) {
276                         rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
277                                 fname);
278                 }
279                 kept = 1;
280                 do_unlink(fname);
281         }
282
283         if (!kept && S_ISDIR(file->mode)) {
284                 /* make an empty directory */
285                 if (do_mkdir(buf, file->mode) < 0) {
286                         int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
287                         if (errno == ENOENT && make_bak_dir(buf) == 0) {
288                                 if (do_mkdir(buf, file->mode) < 0)
289                                         save_errno = errno ? errno : save_errno;
290                                 else
291                                         save_errno = 0;
292                         }
293                         if (save_errno) {
294                                 rsyserr(FINFO, save_errno, "mkdir %s failed",
295                                         full_fname(buf));
296                         }
297                 }
298
299                 ret_code = do_rmdir(fname);
300                 if (verbose > 2) {
301                         rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
302                                 full_fname(fname), ret_code);
303                 }
304                 kept = 1;
305         }
306
307 #ifdef SUPPORT_LINKS
308         if (!kept && preserve_links && S_ISLNK(file->mode)) {
309                 const char *sl = F_SYMLINK(file);
310                 if (safe_symlinks && unsafe_symlink(sl, fname)) {
311                         if (verbose) {
312                                 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
313                                         full_fname(buf), sl);
314                         }
315                         kept = 1;
316                 } else {
317                         do_unlink(buf);
318                         if (do_symlink(sl, buf) < 0) {
319                                 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
320                                 if (errno == ENOENT && make_bak_dir(buf) == 0) {
321                                         if (do_symlink(sl, buf) < 0)
322                                                 save_errno = errno ? errno : save_errno;
323                                         else
324                                                 save_errno = 0;
325                                 }
326                                 if (save_errno) {
327                                         rsyserr(FERROR, save_errno, "link %s -> \"%s\"",
328                                                 full_fname(buf), sl);
329                                 }
330                         }
331                         do_unlink(fname);
332                         kept = 1;
333                 }
334         }
335 #endif
336
337         if (!kept && !S_ISREG(file->mode)) {
338                 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
339                         fname);
340                 unmake_file(file);
341 #ifdef SUPPORT_ACLS
342                 uncache_tmp_acls();
343 #endif
344 #ifdef SUPPORT_XATTRS
345                 uncache_tmp_xattrs();
346 #endif
347                 return 1;
348         }
349
350         /* move to keep tree if a file */
351         if (!kept) {
352                 if (robust_move(fname, buf) != 0) {
353                         rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
354                                 full_fname(fname), buf);
355                 } else if (sx.st.st_nlink > 1) {
356                         /* If someone has hard-linked the file into the backup
357                          * dir, rename() might return success but do nothing! */
358                         robust_unlink(fname); /* Just in case... */
359                 }
360         }
361         preserve_xattrs = 0;
362         set_file_attrs(buf, file, NULL, fname, 0);
363         preserve_xattrs = save_preserve_xattrs;
364         unmake_file(file);
365 #ifdef SUPPORT_ACLS
366         uncache_tmp_acls();
367 #endif
368 #ifdef SUPPORT_XATTRS
369         uncache_tmp_xattrs();
370 #endif
371
372         if (verbose > 1) {
373                 rprintf(FINFO, "backed up %s to %s\n",
374                         fname, buf);
375         }
376         return 1;
377 }
378
379
380 /* main backup switch routine */
381 int make_backup(const char *fname)
382 {
383         if (backup_dir)
384                 return keep_backup(fname);
385         return make_simple_backup(fname);
386 }