1: /*
2: * Backup handling code.
3: *
4: * Copyright (C) 1999 Andrew Tridgell
5: * Copyright (C) 2003-2013 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: #include "ifuncs.h"
23:
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: /* Returns -1 on error, 0 on missing dir, and 1 on present dir. */
38: static int validate_backup_dir(void)
39: {
40: STRUCT_STAT st;
41:
42: if (do_lstat(backup_dir_buf, &st) < 0) {
43: if (errno == ENOENT)
44: return 0;
45: rsyserr(FERROR, errno, "backup lstat %s failed", backup_dir_buf);
46: return -1;
47: }
48: if (!S_ISDIR(st.st_mode)) {
49: int flags = get_del_for_flag(st.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
50: if (delete_item(backup_dir_buf, st.st_mode, flags) == 0)
51: return 0;
52: return -1;
53: }
54: return 1;
55: }
56:
57: /* Create a backup path from the given fname, putting the result into
58: * backup_dir_buf. Any new directories (compared to the prior backup
59: * path) are ensured to exist as directories, replacing anything else
60: * that may be in the way (e.g. a symlink). */
61: static BOOL copy_valid_path(const char *fname)
62: {
63: const char *f;
64: int val;
65: BOOL ret = True;
66: stat_x sx;
67: char *b, *rel = backup_dir_buf + backup_dir_len, *name = rel;
68:
69: for (f = fname, b = rel; *f && *f == *b; f++, b++) {
70: if (*b == '/')
71: name = b + 1;
72: }
73:
74: if (stringjoin(rel, backup_dir_remainder, fname, backup_suffix, NULL) >= backup_dir_remainder) {
75: rprintf(FERROR, "backup filename too long\n");
76: *name = '\0';
77: return False;
78: }
79:
80: for ( ; ; name = b + 1) {
81: if ((b = strchr(name, '/')) == NULL)
82: return True;
83: *b = '\0';
84:
85: val = validate_backup_dir();
86: if (val == 0)
87: break;
88: if (val < 0) {
89: *name = '\0';
90: return False;
91: }
92:
93: *b = '/';
94: }
95:
96: init_stat_x(&sx);
97:
98: for ( ; b; name = b + 1, b = strchr(name, '/')) {
99: *b = '\0';
100:
101: while (do_mkdir(backup_dir_buf, ACCESSPERMS) < 0) {
102: if (errno == EEXIST) {
103: val = validate_backup_dir();
104: if (val > 0)
105: break;
106: if (val == 0)
107: continue;
108: } else
109: rsyserr(FERROR, errno, "backup mkdir %s failed", backup_dir_buf);
110: *name = '\0';
111: ret = False;
112: goto cleanup;
113: }
114:
115: /* Try to transfer the directory settings of the actual dir
116: * that the files are coming from. */
117: if (x_stat(rel, &sx.st, NULL) < 0)
118: rsyserr(FERROR, errno, "backup stat %s failed", full_fname(rel));
119: else {
120: struct file_struct *file;
121: if (!(file = make_file(rel, NULL, NULL, 0, NO_FILTERS)))
122: continue;
123: #ifdef SUPPORT_ACLS
124: if (preserve_acls && !S_ISLNK(file->mode)) {
125: get_acl(rel, &sx);
126: cache_tmp_acl(file, &sx);
127: free_acl(&sx);
128: }
129: #endif
130: #ifdef SUPPORT_XATTRS
131: if (preserve_xattrs) {
132: get_xattr(rel, &sx);
133: cache_tmp_xattr(file, &sx);
134: free_xattr(&sx);
135: }
136: #endif
137: set_file_attrs(backup_dir_buf, file, NULL, NULL, 0);
138: unmake_file(file);
139: }
140:
141: *b = '/';
142: }
143:
144: cleanup:
145:
146: #ifdef SUPPORT_ACLS
147: uncache_tmp_acls();
148: #endif
149: #ifdef SUPPORT_XATTRS
150: uncache_tmp_xattrs();
151: #endif
152:
153: return ret;
154: }
155:
156: /* Make a complete pathname for backup file and verify any new path elements. */
157: char *get_backup_name(const char *fname)
158: {
159: if (backup_dir) {
160: /* copy fname into backup_dir_buf while validating the dirs. */
161: if (copy_valid_path(fname))
162: return backup_dir_buf;
163: /* copy_valid_path() has printed an error message. */
164: return NULL;
165: }
166:
167: if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
168: return backup_dir_buf;
169:
170: rprintf(FERROR, "backup filename too long\n");
171: return NULL;
172: }
173:
174: /* Has same return codes as make_backup(). */
175: static inline int link_or_rename(const char *from, const char *to,
176: BOOL prefer_rename, STRUCT_STAT *stp)
177: {
178: #ifdef SUPPORT_HARD_LINKS
179: if (!prefer_rename) {
180: #ifndef CAN_HARDLINK_SYMLINK
181: if (S_ISLNK(stp->st_mode))
182: return 0; /* Use copy code. */
183: #endif
184: #ifndef CAN_HARDLINK_SPECIAL
185: if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode))
186: return 0; /* Use copy code. */
187: #endif
188: if (do_link(from, to) == 0) {
189: if (DEBUG_GTE(BACKUP, 1))
190: rprintf(FINFO, "make_backup: HLINK %s successful.\n", from);
191: return 2;
192: }
193: /* We prefer to rename a regular file rather than copy it. */
194: if (!S_ISREG(stp->st_mode) || errno == EEXIST || errno == EISDIR)
195: return 0;
196: }
197: #endif
198: if (do_rename(from, to) == 0) {
199: if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) {
200: /* If someone has hard-linked the file into the backup
201: * dir, rename() might return success but do nothing! */
202: robust_unlink(from); /* Just in case... */
203: }
204: if (DEBUG_GTE(BACKUP, 1))
205: rprintf(FINFO, "make_backup: RENAME %s successful.\n", from);
206: return 1;
207: }
208: return 0;
209: }
210:
211: /* Hard-link, rename, or copy an item to the backup name. Returns 2 if item
212: * was duplicated into backup area, 1 if item was moved, or 0 for failure.*/
213: int make_backup(const char *fname, BOOL prefer_rename)
214: {
215: stat_x sx;
216: struct file_struct *file;
217: int save_preserve_xattrs;
218: char *buf = get_backup_name(fname);
219: int ret = 0;
220:
221: if (!buf)
222: return 0;
223:
224: init_stat_x(&sx);
225: /* Return success if no file to keep. */
226: if (x_lstat(fname, &sx.st, NULL) < 0)
227: return 1;
228:
229: /* Try a hard-link or a rename first. Using rename is not atomic, but
230: * is more efficient than forcing a copy for larger files when no hard-
231: * linking is possible. */
232: if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
233: goto success;
234: if (errno == EEXIST || errno == EISDIR) {
235: STRUCT_STAT bakst;
236: if (do_lstat(buf, &bakst) == 0) {
237: int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
238: if (delete_item(buf, bakst.st_mode, flags) != 0)
239: return 0;
240: }
241: if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
242: goto success;
243: }
244:
245: /* Fall back to making a copy. */
246: if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
247: return 1; /* the file could have disappeared */
248:
249: #ifdef SUPPORT_ACLS
250: if (preserve_acls && !S_ISLNK(file->mode)) {
251: get_acl(fname, &sx);
252: cache_tmp_acl(file, &sx);
253: free_acl(&sx);
254: }
255: #endif
256: #ifdef SUPPORT_XATTRS
257: if (preserve_xattrs) {
258: get_xattr(fname, &sx);
259: cache_tmp_xattr(file, &sx);
260: free_xattr(&sx);
261: }
262: #endif
263:
264: /* Check to see if this is a device file, or link */
265: if ((am_root && preserve_devices && IS_DEVICE(file->mode))
266: || (preserve_specials && IS_SPECIAL(file->mode))) {
267: if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
268: rsyserr(FERROR, errno, "mknod %s failed", full_fname(buf));
269: else if (DEBUG_GTE(BACKUP, 1))
270: rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
271: ret = 2;
272: }
273:
274: #ifdef SUPPORT_LINKS
275: if (!ret && preserve_links && S_ISLNK(file->mode)) {
276: const char *sl = F_SYMLINK(file);
277: if (safe_symlinks && unsafe_symlink(sl, fname)) {
278: if (INFO_GTE(SYMSAFE, 1)) {
279: rprintf(FINFO, "not backing up unsafe symlink \"%s\" -> \"%s\"\n",
280: fname, sl);
281: }
282: ret = 2;
283: } else {
284: if (do_symlink(sl, buf) < 0)
285: rsyserr(FERROR, errno, "link %s -> \"%s\"", full_fname(buf), sl);
286: else if (DEBUG_GTE(BACKUP, 1))
287: rprintf(FINFO, "make_backup: SYMLINK %s successful.\n", fname);
288: ret = 2;
289: }
290: }
291: #endif
292:
293: if (!ret && !S_ISREG(file->mode)) {
294: rprintf(FINFO, "make_bak: skipping non-regular file %s\n", fname);
295: unmake_file(file);
296: #ifdef SUPPORT_ACLS
297: uncache_tmp_acls();
298: #endif
299: #ifdef SUPPORT_XATTRS
300: uncache_tmp_xattrs();
301: #endif
302: return 2;
303: }
304:
305: /* Copy to backup tree if a file. */
306: if (!ret) {
307: if (copy_file(fname, buf, -1, file->mode) < 0) {
308: rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
309: full_fname(fname), buf);
310: unmake_file(file);
311: #ifdef SUPPORT_ACLS
312: uncache_tmp_acls();
313: #endif
314: #ifdef SUPPORT_XATTRS
315: uncache_tmp_xattrs();
316: #endif
317: return 0;
318: }
319: if (DEBUG_GTE(BACKUP, 1))
320: rprintf(FINFO, "make_backup: COPY %s successful.\n", fname);
321: ret = 2;
322: }
323:
324: save_preserve_xattrs = preserve_xattrs;
325: preserve_xattrs = 0;
326: set_file_attrs(buf, file, NULL, fname, 0);
327: preserve_xattrs = save_preserve_xattrs;
328:
329: unmake_file(file);
330: #ifdef SUPPORT_ACLS
331: uncache_tmp_acls();
332: #endif
333: #ifdef SUPPORT_XATTRS
334: uncache_tmp_xattrs();
335: #endif
336:
337: success:
338: if (INFO_GTE(BACKUP, 1))
339: rprintf(FINFO, "backed up %s to %s\n", fname, buf);
340: return ret;
341: }
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