1: /*
2: * Backup handling code.
3: *
4: * Copyright (C) 1999 Andrew Tridgell
5: * Copyright (C) 2003-2015 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: static int initialized = 0;
161: if (!initialized) {
162: int ret;
163: if (backup_dir_len > 1)
164: backup_dir_buf[backup_dir_len-1] = '\0';
165: ret = make_path(backup_dir_buf, 0);
166: if (backup_dir_len > 1)
167: backup_dir_buf[backup_dir_len-1] = '/';
168: if (ret < 0)
169: return NULL;
170: initialized = 1;
171: }
172: /* copy fname into backup_dir_buf while validating the dirs. */
173: if (copy_valid_path(fname))
174: return backup_dir_buf;
175: /* copy_valid_path() has printed an error message. */
176: return NULL;
177: }
178:
179: if (stringjoin(backup_dir_buf, MAXPATHLEN, fname, backup_suffix, NULL) < MAXPATHLEN)
180: return backup_dir_buf;
181:
182: rprintf(FERROR, "backup filename too long\n");
183: return NULL;
184: }
185:
186: /* Has same return codes as make_backup(). */
187: static inline int link_or_rename(const char *from, const char *to,
188: BOOL prefer_rename, STRUCT_STAT *stp)
189: {
190: #ifdef SUPPORT_HARD_LINKS
191: if (!prefer_rename) {
192: #ifndef CAN_HARDLINK_SYMLINK
193: if (S_ISLNK(stp->st_mode))
194: return 0; /* Use copy code. */
195: #endif
196: #ifndef CAN_HARDLINK_SPECIAL
197: if (IS_SPECIAL(stp->st_mode) || IS_DEVICE(stp->st_mode))
198: return 0; /* Use copy code. */
199: #endif
200: if (do_link(from, to) == 0) {
201: if (DEBUG_GTE(BACKUP, 1))
202: rprintf(FINFO, "make_backup: HLINK %s successful.\n", from);
203: return 2;
204: }
205: /* We prefer to rename a regular file rather than copy it. */
206: if (!S_ISREG(stp->st_mode) || errno == EEXIST || errno == EISDIR)
207: return 0;
208: }
209: #endif
210: if (do_rename(from, to) == 0) {
211: if (stp->st_nlink > 1 && !S_ISDIR(stp->st_mode)) {
212: /* If someone has hard-linked the file into the backup
213: * dir, rename() might return success but do nothing! */
214: robust_unlink(from); /* Just in case... */
215: }
216: if (DEBUG_GTE(BACKUP, 1))
217: rprintf(FINFO, "make_backup: RENAME %s successful.\n", from);
218: return 1;
219: }
220: return 0;
221: }
222:
223: /* Hard-link, rename, or copy an item to the backup name. Returns 0 for
224: * failure, 1 if item was moved, 2 if item was duplicated or hard linked
225: * into backup area, or 3 if item doesn't exist or isn't a regular file. */
226: int make_backup(const char *fname, BOOL prefer_rename)
227: {
228: stat_x sx;
229: struct file_struct *file;
230: int save_preserve_xattrs;
231: char *buf;
232: int ret = 0;
233:
234: init_stat_x(&sx);
235: /* Return success if no file to keep. */
236: if (x_lstat(fname, &sx.st, NULL) < 0)
237: return 3;
238:
239: if (!(buf = get_backup_name(fname)))
240: return 0;
241:
242: /* Try a hard-link or a rename first. Using rename is not atomic, but
243: * is more efficient than forcing a copy for larger files when no hard-
244: * linking is possible. */
245: if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
246: goto success;
247: if (errno == EEXIST || errno == EISDIR) {
248: STRUCT_STAT bakst;
249: if (do_lstat(buf, &bakst) == 0) {
250: int flags = get_del_for_flag(bakst.st_mode) | DEL_FOR_BACKUP | DEL_RECURSE;
251: if (delete_item(buf, bakst.st_mode, flags) != 0)
252: return 0;
253: }
254: if ((ret = link_or_rename(fname, buf, prefer_rename, &sx.st)) != 0)
255: goto success;
256: }
257:
258: /* Fall back to making a copy. */
259: if (!(file = make_file(fname, NULL, &sx.st, 0, NO_FILTERS)))
260: return 3; /* the file could have disappeared */
261:
262: #ifdef SUPPORT_ACLS
263: if (preserve_acls && !S_ISLNK(file->mode)) {
264: get_acl(fname, &sx);
265: cache_tmp_acl(file, &sx);
266: free_acl(&sx);
267: }
268: #endif
269: #ifdef SUPPORT_XATTRS
270: if (preserve_xattrs) {
271: get_xattr(fname, &sx);
272: cache_tmp_xattr(file, &sx);
273: free_xattr(&sx);
274: }
275: #endif
276:
277: /* Check to see if this is a device file, or link */
278: if ((am_root && preserve_devices && IS_DEVICE(file->mode))
279: || (preserve_specials && IS_SPECIAL(file->mode))) {
280: if (do_mknod(buf, file->mode, sx.st.st_rdev) < 0)
281: rsyserr(FERROR, errno, "mknod %s failed", full_fname(buf));
282: else if (DEBUG_GTE(BACKUP, 1))
283: rprintf(FINFO, "make_backup: DEVICE %s successful.\n", fname);
284: ret = 2;
285: }
286:
287: #ifdef SUPPORT_LINKS
288: if (!ret && preserve_links && S_ISLNK(file->mode)) {
289: const char *sl = F_SYMLINK(file);
290: if (safe_symlinks && unsafe_symlink(sl, fname)) {
291: if (INFO_GTE(SYMSAFE, 1)) {
292: rprintf(FINFO, "not backing up unsafe symlink \"%s\" -> \"%s\"\n",
293: fname, sl);
294: }
295: ret = 2;
296: } else {
297: if (do_symlink(sl, buf) < 0)
298: rsyserr(FERROR, errno, "link %s -> \"%s\"", full_fname(buf), sl);
299: else if (DEBUG_GTE(BACKUP, 1))
300: rprintf(FINFO, "make_backup: SYMLINK %s successful.\n", fname);
301: ret = 2;
302: }
303: }
304: #endif
305:
306: if (!ret && !S_ISREG(file->mode)) {
307: rprintf(FINFO, "make_bak: skipping non-regular file %s\n", fname);
308: unmake_file(file);
309: #ifdef SUPPORT_ACLS
310: uncache_tmp_acls();
311: #endif
312: #ifdef SUPPORT_XATTRS
313: uncache_tmp_xattrs();
314: #endif
315: return 3;
316: }
317:
318: /* Copy to backup tree if a file. */
319: if (!ret) {
320: if (copy_file(fname, buf, -1, file->mode) < 0) {
321: rsyserr(FERROR, errno, "keep_backup failed: %s -> \"%s\"",
322: full_fname(fname), buf);
323: unmake_file(file);
324: #ifdef SUPPORT_ACLS
325: uncache_tmp_acls();
326: #endif
327: #ifdef SUPPORT_XATTRS
328: uncache_tmp_xattrs();
329: #endif
330: return 0;
331: }
332: if (DEBUG_GTE(BACKUP, 1))
333: rprintf(FINFO, "make_backup: COPY %s successful.\n", fname);
334: ret = 2;
335: }
336:
337: save_preserve_xattrs = preserve_xattrs;
338: preserve_xattrs = 0;
339: set_file_attrs(buf, file, NULL, fname, 0);
340: preserve_xattrs = save_preserve_xattrs;
341:
342: unmake_file(file);
343: #ifdef SUPPORT_ACLS
344: uncache_tmp_acls();
345: #endif
346: #ifdef SUPPORT_XATTRS
347: uncache_tmp_xattrs();
348: #endif
349:
350: success:
351: if (INFO_GTE(BACKUP, 1))
352: rprintf(FINFO, "backed up %s to %s\n", fname, buf);
353: return ret;
354: }
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