Handle simultaneous arrival of multiple connections.
[rsync/rsync.git] / backup.c
CommitLineData
addf0c4a 1/*
0f78b815
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2 * Backup handling code.
3 *
4 * Copyright (C) 1999 Andrew Tridgell
b3bf9b9d 5 * Copyright (C) 2003-2009 Wayne Davison
0f78b815
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6 *
7 * This program is free software; you can redistribute it and/or modify
8e41b68e
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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.
0f78b815
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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 *
e7c67065 17 * You should have received a copy of the GNU General Public License along
4fd842f9 18 * with this program; if not, visit the http://fsf.org website.
0f78b815 19 */
3d19b4c8
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20
21#include "rsync.h"
09ca0d15 22#include "ifuncs.h"
3d19b4c8 23
378a074c 24extern int am_root;
1c3344a1 25extern int preserve_acls;
16edf865 26extern int preserve_xattrs;
378a074c 27extern int preserve_devices;
b5c6a6ae 28extern int preserve_specials;
378a074c 29extern int preserve_links;
377dbd20 30extern int safe_symlinks;
6b2a3d5d 31extern int backup_dir_len;
82ad07c4
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32extern unsigned int backup_dir_remainder;
33extern char backup_dir_buf[MAXPATHLEN];
34extern char *backup_suffix;
35extern char *backup_dir;
378a074c 36
c94e4afb 37/* make a complete pathname for backup file */
45d8bfe0 38char *get_backup_name(const char *fname)
c94e4afb 39{
c94e4afb
WD
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 {
fb22c277
WD
45 if (stringjoin(backup_dir_buf, MAXPATHLEN,
46 fname, backup_suffix, NULL) < MAXPATHLEN)
47 return backup_dir_buf;
c94e4afb
WD
48 }
49
50 rprintf(FERROR, "backup filename too long\n");
51 return NULL;
52}
53
378a074c
AT
54/****************************************************************************
55Create a directory given an absolute path, perms based upon another directory
56path
57****************************************************************************/
e1ac7791 58int make_bak_dir(const char *fullpath)
378a074c 59{
e1ac7791 60 char fbuf[MAXPATHLEN], *rel, *end, *p;
1c3344a1 61 struct file_struct *file;
e1ac7791 62 int len = backup_dir_len;
13710874 63 stat_x sx;
de0e2250 64
e1ac7791 65 while (*fullpath == '.' && fullpath[1] == '/') {
de0e2250 66 fullpath += 2;
e1ac7791
WD
67 len -= 2;
68 }
69
70 if (strlcpy(fbuf, fullpath, sizeof fbuf) >= sizeof fbuf)
71 return -1;
72
73 rel = fbuf + len;
74 end = p = rel + strlen(rel);
de0e2250
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75
76 /* Try to find an existing dir, starting from the deepest dir. */
77 while (1) {
e1ac7791
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78 if (--p == fbuf)
79 return -1;
de0e2250
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80 if (*p == '/') {
81 *p = '\0';
e1ac7791 82 if (mkdir_defmode(fbuf) == 0)
de0e2250
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83 break;
84 if (errno != ENOENT) {
d62bcc17
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85 rsyserr(FERROR, errno,
86 "make_bak_dir mkdir %s failed",
e1ac7791
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87 full_fname(fbuf));
88 return -1;
de0e2250
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89 }
90 }
47d6a60c 91 }
de0e2250
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92
93 /* Make all the dirs that we didn't find on the way here. */
94 while (1) {
95 if (p >= rel) {
96 /* Try to transfer the directory settings of the
97 * actual dir that the files are coming from. */
09ca0d15 98 init_stat_x(&sx);
9439c0cb 99 if (x_stat(rel, &sx.st, NULL) < 0) {
d62bcc17
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100 rsyserr(FERROR, errno,
101 "make_bak_dir stat %s failed",
102 full_fname(rel));
de0e2250 103 } else {
1c3344a1
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104 if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
105 continue;
106#ifdef SUPPORT_ACLS
107 if (preserve_acls && !S_ISLNK(file->mode)) {
108 get_acl(rel, &sx);
109 cache_acl(file, &sx);
110 free_acl(&sx);
111 }
1e999f9f 112#endif
16edf865
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113#ifdef SUPPORT_XATTRS
114 if (preserve_xattrs) {
115 get_xattr(rel, &sx);
116 cache_xattr(file, &sx);
117 free_xattr(&sx);
118 }
119#endif
e1ac7791 120 set_file_attrs(fbuf, file, NULL, NULL, 0);
b13505da 121 unmake_file(file);
47d6a60c
S
122 }
123 }
de0e2250
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124 *p = '/';
125 p += strlen(p);
126 if (p == end)
127 break;
e1ac7791 128 if (mkdir_defmode(fbuf) < 0) {
d62bcc17 129 rsyserr(FERROR, errno, "make_bak_dir mkdir %s failed",
e1ac7791
WD
130 full_fname(fbuf));
131 return -1;
de0e2250 132 }
47d6a60c 133 }
de0e2250 134
e1ac7791 135 return 0;
378a074c
AT
136}
137
21cddef2
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138/* Has same return codes as make_backup(). */
139static inline int link_or_rename(const char *from, const char *to,
140 BOOL prefer_rename, STRUCT_STAT *stp)
66203a98 141{
21cddef2
WD
142 if (S_ISLNK(stp->st_mode)) {
143 if (prefer_rename)
144 goto do_rename;
145#ifndef CAN_HARDLINK_SYMLINK
146 return 0; /* Use copy code. */
147#endif
148 }
149 if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode)) {
150 if (prefer_rename)
151 goto do_rename;
152#ifndef CAN_HARDLINK_SPECIAL
153 return 0; /* Use copy code. */
154#endif
155 }
156#ifdef SUPPORT_HARD_LINKS
157 if (!S_ISDIR(stp->st_mode)) {
158 if (do_link(from, to) == 0)
159 return 2;
160 return 0;
161 }
162#endif
163 do_rename:
164 if (do_rename(from, to) == 0) {
165 if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) {
166 /* If someone has hard-linked the file into the backup
167 * dir, rename() might return success but do nothing! */
168 robust_unlink(to); /* Just in case... */
f1ca7c44 169 }
21cddef2 170 return 1;
f1ca7c44 171 }
62c9e6b3 172 return 0;
de0e2250 173}
66203a98 174
21cddef2
WD
175/* Hard-link, rename, or copy an item to the backup name. Returns 2 if item
176 * was duplicated into backup area, 1 if item was moved, or 0 for failure.*/
177int make_backup(const char *fname, BOOL prefer_rename)
66203a98 178{
13710874 179 stat_x sx;
66203a98 180 struct file_struct *file;
21cddef2
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181 int save_preserve_xattrs;
182 char *buf = get_backup_name(fname);
183 int ret = 0;
184
185 if (!buf)
186 return 0;
378a074c 187
09ca0d15
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188 init_stat_x(&sx);
189 /* Return success if no file to keep. */
9439c0cb 190 if (x_lstat(fname, &sx.st, NULL) < 0)
9fd62d15 191 return 1;
66203a98 192
21cddef2
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193 /* Try a hard-link or a rename first. Using rename is not atomic, but
194 * is more efficient than forcing a copy for larger files when no hard-
195 * linking is possible. */
196 if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
197 goto success;
198 if (errno == EEXIST) {
199 STRUCT_STAT bakst;
200 if (do_lstat(buf, &bakst) == 0) {
201 int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
202 if (delete_item(buf, bakst.st_mode, flags) != 0)
203 return 0;
204 }
205 if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
206 goto success;
207 } else if (backup_dir && errno == ENOENT) {
208 /* If the backup dir is missing, try again after making it. */
209 if (make_bak_dir(buf) != 0)
210 return 0;
211 if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
212 goto success;
82ad07c4 213 }
378a074c 214
21cddef2
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215 /* Fall back to making a copy. */
216 if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
217 return 1; /* the file could have disappeared */
218
1c3344a1
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219#ifdef SUPPORT_ACLS
220 if (preserve_acls && !S_ISLNK(file->mode)) {
221 get_acl(fname, &sx);
222 cache_acl(file, &sx);
223 free_acl(&sx);
224 }
225#endif
16edf865
WD
226#ifdef SUPPORT_XATTRS
227 if (preserve_xattrs) {
228 get_xattr(fname, &sx);
229 cache_xattr(file, &sx);
230 free_xattr(&sx);
231 }
232#endif
1c3344a1 233
378a074c 234 /* Check to see if this is a device file, or link */
b5c6a6ae
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235 if ((am_root && preserve_devices && IS_DEVICE(file->mode))
236 || (preserve_specials && IS_SPECIAL(file->mode))) {
88e05f84 237 int save_errno;
a64f19e2 238 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0) {
88e05f84 239 save_errno = errno ? errno : EINVAL; /* 0 paranoia */
f1ca7c44 240 if (errno == ENOENT && make_bak_dir(buf) == 0) {
a64f19e2 241 if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
f1ca7c44
WD
242 save_errno = errno ? errno : save_errno;
243 else
244 save_errno = 0;
245 }
246 if (save_errno) {
247 rsyserr(FERROR, save_errno, "mknod %s failed",
248 full_fname(buf));
249 }
88e05f84
WD
250 } else
251 save_errno = 0;
951e826b 252 if (DEBUG_GTE(BACKUP, 1) && save_errno == 0) {
93e28fbd 253 rprintf(FINFO, "make_backup: DEVICE %s successful.\n",
45c49b52 254 fname);
47d6a60c 255 }
21cddef2 256 ret = 2;
47d6a60c 257 }
378a074c 258
21cddef2
WD
259 if (!ret && S_ISDIR(file->mode)) {
260 int ret_code;
378a074c 261 /* make an empty directory */
f1ca7c44
WD
262 if (do_mkdir(buf, file->mode) < 0) {
263 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
264 if (errno == ENOENT && make_bak_dir(buf) == 0) {
265 if (do_mkdir(buf, file->mode) < 0)
266 save_errno = errno ? errno : save_errno;
267 else
268 save_errno = 0;
269 }
270 if (save_errno) {
271 rsyserr(FINFO, save_errno, "mkdir %s failed",
272 full_fname(buf));
273 }
377dbd20 274 }
47d6a60c 275
377dbd20 276 ret_code = do_rmdir(fname);
951e826b 277 if (DEBUG_GTE(BACKUP, 1)) {
ea42541f
WD
278 rprintf(FINFO, "make_backup: RMDIR %s returns %i\n",
279 full_fname(fname), ret_code);
47d6a60c 280 }
21cddef2 281 ret = 2;
47d6a60c 282 }
378a074c 283
4f5b0756 284#ifdef SUPPORT_LINKS
21cddef2 285 if (!ret && preserve_links && S_ISLNK(file->mode)) {
82ad07c4
WD
286 const char *sl = F_SYMLINK(file);
287 if (safe_symlinks && unsafe_symlink(sl, buf)) {
951e826b 288 if (INFO_GTE(SYMSAFE, 1)) {
47d6a60c 289 rprintf(FINFO, "ignoring unsafe symlink %s -> %s\n",
82ad07c4 290 full_fname(buf), sl);
47d6a60c 291 }
21cddef2 292 ret = 2;
93e28fbd 293 } else {
f1ca7c44
WD
294 if (do_symlink(sl, buf) < 0) {
295 int save_errno = errno ? errno : EINVAL; /* 0 paranoia */
296 if (errno == ENOENT && make_bak_dir(buf) == 0) {
297 if (do_symlink(sl, buf) < 0)
298 save_errno = errno ? errno : save_errno;
299 else
300 save_errno = 0;
301 }
302 if (save_errno) {
303 rsyserr(FERROR, save_errno, "link %s -> \"%s\"",
304 full_fname(buf), sl);
305 }
93e28fbd 306 }
21cddef2 307 ret = 2;
47d6a60c 308 }
47d6a60c 309 }
378a074c 310#endif
378a074c 311
21cddef2 312 if (!ret && !S_ISREG(file->mode)) {
47d6a60c 313 rprintf(FINFO, "make_bak: skipping non-regular file %s\n",
45c49b52 314 fname);
82ad07c4 315 unmake_file(file);
21cddef2 316 return 2;
47d6a60c 317 }
66203a98 318
21cddef2
WD
319 /* Copy to backup tree if a file. */
320 if (!ret) {
321 if (copy_file(fname, buf, -1, file->mode, 1) < 0) {
d62bcc17 322 rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
45c49b52 323 full_fname(fname), buf);
21cddef2
WD
324 unmake_file(file);
325 return 0;
47d6a60c 326 }
21cddef2 327 ret = 2;
47d6a60c 328 }
21cddef2
WD
329
330 save_preserve_xattrs = preserve_xattrs;
e9489cd6 331 preserve_xattrs = 0;
16edf865 332 set_file_attrs(buf, file, NULL, fname, 0);
e9489cd6 333 preserve_xattrs = save_preserve_xattrs;
21cddef2 334
82ad07c4 335 unmake_file(file);
378a074c 336
21cddef2 337 success:
951e826b 338 if (INFO_GTE(BACKUP, 1)) {
4875d6b6 339 rprintf(FINFO, "backed up %s to %s\n",
45c49b52 340 fname, buf);
4875d6b6 341 }
21cddef2 342 return ret;
66203a98 343}