source: MondoRescue/branches/3.3/mindi-busybox/libbb/copy_file.c@ 3621

Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
File size: 11.8 KB
RevLine 
[821]1/* vi: set sw=4 ts=4: */
2/*
3 * Mini copy_file implementation for busybox
4 *
5 * Copyright (C) 2001 by Matt Kraai <kraai@alumni.carnegiemellon.edu>
[1765]6 * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp>
[821]7 *
[2725]8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
[821]9 */
10#include "libbb.h"
11
[2725]12// FEATURE_NON_POSIX_CP:
13//
[1765]14// POSIX: if exists and -i, ask (w/o -i assume yes).
15// Then open w/o EXCL (yes, not unlink!).
16// If open still fails and -f, try unlink, then try open again.
17// Result: a mess:
[2725]18// If dest is a (sym)link, we overwrite link destination!
[1765]19// (or fail, if it points to dir/nonexistent location/etc).
20// This is strange, but POSIX-correct.
21// coreutils cp has --remove-destination to override this...
22
[2725]23/* Called if open of destination, link creation etc fails.
24 * errno must be set to relevant value ("why we cannot create dest?")
25 * to give reasonable error message */
[1765]26static int ask_and_unlink(const char *dest, int flags)
27{
[2725]28 int e = errno;
29
30#if !ENABLE_FEATURE_NON_POSIX_CP
[1765]31 if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) {
[2725]32 /* Either it exists, or the *path* doesnt exist */
33 bb_perror_msg("can't create '%s'", dest);
[1765]34 return -1;
35 }
36#endif
[2725]37 // else: act as if -f is always in effect.
38 // We don't want "can't create" msg, we want unlink to be done
39 // (silently unless -i). Why? POSIX cp usually succeeds with
40 // O_TRUNC open of existing file, and user is left ignorantly happy.
41 // With above block unconditionally enabled, non-POSIX cp
42 // will complain a lot more than POSIX one.
[1765]43
[2725]44 /* TODO: maybe we should do it only if ctty is present? */
[1765]45 if (flags & FILEUTILS_INTERACTIVE) {
46 // We would not do POSIX insanity. -i asks,
47 // then _unlinks_ the offender. Presto.
48 // (No "opening without O_EXCL", no "unlink only if -f")
49 // Or else we will end up having 3 open()s!
50 fprintf(stderr, "%s: overwrite '%s'? ", applet_name, dest);
51 if (!bb_ask_confirmation())
[2725]52 return 0; /* not allowed to overwrite */
[1765]53 }
54 if (unlink(dest) < 0) {
[2725]55#if ENABLE_FEATURE_VERBOSE_CP_MESSAGE
56 if (e == errno && e == ENOENT) {
57 /* e == ENOTDIR is similar: path has non-dir component,
58 * but in this case we don't even reach copy_file() */
59 bb_error_msg("can't create '%s': Path does not exist", dest);
60 return -1; /* error */
61 }
62#endif
63 errno = e; /* do not use errno from unlink */
64 bb_perror_msg("can't create '%s'", dest);
65 return -1; /* error */
[1765]66 }
[3621]67#if ENABLE_FEATURE_CP_LONG_OPTIONS
68 if (flags & FILEUTILS_RMDEST)
69 if (flags & FILEUTILS_VERBOSE)
70 printf("removed '%s'\n", dest);
71#endif
[2725]72 return 1; /* ok (to try again) */
[1765]73}
74
75/* Return:
76 * -1 error, copy not made
77 * 0 copy is made or user answered "no" in interactive mode
78 * (failures to preserve mode/owner/times are not reported in exit code)
79 */
[2725]80int FAST_FUNC copy_file(const char *source, const char *dest, int flags)
[821]81{
[1765]82 /* This is a recursive function, try to minimize stack usage */
83 /* NB: each struct stat is ~100 bytes */
[821]84 struct stat source_stat;
85 struct stat dest_stat;
[3232]86 smallint retval = 0;
87 smallint dest_exists = 0;
88 smallint ovr;
[821]89
[2725]90/* Inverse of cp -d ("cp without -d") */
91#define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0))
[1765]92
93 if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
[2725]94 /* This may be a dangling symlink.
95 * Making [sym]links to dangling symlinks works, so... */
[1765]96 if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK))
97 goto make_links;
[2725]98 bb_perror_msg("can't stat '%s'", source);
[821]99 return -1;
100 }
101
102 if (lstat(dest, &dest_stat) < 0) {
103 if (errno != ENOENT) {
[2725]104 bb_perror_msg("can't stat '%s'", dest);
[821]105 return -1;
106 }
107 } else {
[1765]108 if (source_stat.st_dev == dest_stat.st_dev
109 && source_stat.st_ino == dest_stat.st_ino
110 ) {
111 bb_error_msg("'%s' and '%s' are the same file", source, dest);
[821]112 return -1;
113 }
114 dest_exists = 1;
115 }
116
[1765]117#if ENABLE_SELINUX
118 if ((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT) && is_selinux_enabled() > 0) {
119 security_context_t con;
120 if (lgetfilecon(source, &con) >= 0) {
121 if (setfscreatecon(con) < 0) {
[2725]122 bb_perror_msg("can't set setfscreatecon %s", con);
[1765]123 freecon(con);
124 return -1;
125 }
126 } else if (errno == ENOTSUP || errno == ENODATA) {
127 setfscreatecon_or_die(NULL);
128 } else {
[2725]129 bb_perror_msg("can't lgetfilecon %s", source);
[1765]130 return -1;
131 }
132 }
133#endif
134
[821]135 if (S_ISDIR(source_stat.st_mode)) {
136 DIR *dp;
[1765]137 const char *tp;
[821]138 struct dirent *d;
139 mode_t saved_umask = 0;
140
141 if (!(flags & FILEUTILS_RECUR)) {
[1765]142 bb_error_msg("omitting directory '%s'", source);
[821]143 return -1;
144 }
145
[1765]146 /* Did we ever create source ourself before? */
147 tp = is_in_ino_dev_hashtable(&source_stat);
148 if (tp) {
149 /* We did! it's a recursion! man the lifeboats... */
150 bb_error_msg("recursion detected, omitting directory '%s'",
151 source);
152 return -1;
153 }
154
[821]155 if (dest_exists) {
156 if (!S_ISDIR(dest_stat.st_mode)) {
[1765]157 bb_error_msg("target '%s' is not a directory", dest);
[821]158 return -1;
159 }
[1765]160 /* race here: user can substitute a symlink between
161 * this check and actual creation of files inside dest */
[821]162 } else {
[3232]163 /* Create DEST */
[821]164 mode_t mode;
165 saved_umask = umask(0);
166
167 mode = source_stat.st_mode;
168 if (!(flags & FILEUTILS_PRESERVE_STATUS))
169 mode = source_stat.st_mode & ~saved_umask;
[1765]170 /* Allow owner to access new dir (at least for now) */
[821]171 mode |= S_IRWXU;
172 if (mkdir(dest, mode) < 0) {
173 umask(saved_umask);
[2725]174 bb_perror_msg("can't create directory '%s'", dest);
[821]175 return -1;
176 }
177 umask(saved_umask);
[1765]178 /* need stat info for add_to_ino_dev_hashtable */
179 if (lstat(dest, &dest_stat) < 0) {
[2725]180 bb_perror_msg("can't stat '%s'", dest);
[1765]181 return -1;
182 }
[821]183 }
[1765]184 /* remember (dev,inode) of each created dir.
185 * NULL: name is not remembered */
186 add_to_ino_dev_hashtable(&dest_stat, NULL);
[821]187
[1765]188 /* Recursively copy files in SOURCE */
189 dp = opendir(source);
190 if (dp == NULL) {
191 retval = -1;
192 goto preserve_mode_ugid_time;
[821]193 }
194
195 while ((d = readdir(dp)) != NULL) {
196 char *new_source, *new_dest;
197
198 new_source = concat_subpath_file(source, d->d_name);
[1765]199 if (new_source == NULL)
[821]200 continue;
201 new_dest = concat_path_file(dest, d->d_name);
[2725]202 if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0)
[1765]203 retval = -1;
[821]204 free(new_source);
205 free(new_dest);
206 }
207 closedir(dp);
208
[1765]209 if (!dest_exists
210 && chmod(dest, source_stat.st_mode & ~saved_umask) < 0
211 ) {
[2725]212 bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
[1765]213 /* retval = -1; - WRONG! copy *WAS* made */
[821]214 }
[1765]215 goto preserve_mode_ugid_time;
216 }
217
[3621]218 if (dest_exists) {
219 if (flags & FILEUTILS_UPDATE) {
220 if (source_stat.st_mtime <= dest_stat.st_mtime) {
221 return 0; /* source file must be newer */
222 }
223 }
224#if ENABLE_FEATURE_CP_LONG_OPTIONS
225 if (flags & FILEUTILS_RMDEST) {
226 ovr = ask_and_unlink(dest, flags);
227 if (ovr <= 0)
228 return ovr;
229 dest_exists = 0;
230 }
231#endif
232 }
233
[1765]234 if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) {
235 int (*lf)(const char *oldpath, const char *newpath);
236 make_links:
[2725]237 /* Hmm... maybe
238 * if (DEREF && MAKE_SOFTLINK) source = realpath(source) ?
239 * (but realpath returns NULL on dangling symlinks...) */
[1765]240 lf = (flags & FILEUTILS_MAKE_SOFTLINK) ? symlink : link;
241 if (lf(source, dest) < 0) {
242 ovr = ask_and_unlink(dest, flags);
243 if (ovr <= 0)
244 return ovr;
245 if (lf(source, dest) < 0) {
[2725]246 bb_perror_msg("can't create link '%s'", dest);
[1765]247 return -1;
248 }
249 }
250 /* _Not_ jumping to preserve_mode_ugid_time:
[2725]251 * (sym)links don't have those */
[1765]252 return 0;
253 }
254
[2725]255 if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
256 !(flags & FILEUTILS_RECUR)
257 /* "cp [-opts] regular_file thing2" */
258 || S_ISREG(source_stat.st_mode)
259 /* DEREF uses stat, which never returns S_ISLNK() == true.
260 * So the below is never true: */
[1765]261 /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
262 ) {
[821]263 int src_fd;
264 int dst_fd;
[2725]265 mode_t new_mode;
[821]266
[2725]267 if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
268 /* "cp -d symlink dst": create a link */
269 goto dont_cat;
270 }
271
[1765]272 if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
273 const char *link_target;
274 link_target = is_in_ino_dev_hashtable(&source_stat);
275 if (link_target) {
276 if (link(link_target, dest) < 0) {
277 ovr = ask_and_unlink(dest, flags);
278 if (ovr <= 0)
279 return ovr;
280 if (link(link_target, dest) < 0) {
[2725]281 bb_perror_msg("can't create link '%s'", dest);
[1765]282 return -1;
283 }
[821]284 }
285 return 0;
286 }
287 add_to_ino_dev_hashtable(&source_stat, dest);
288 }
289
[1765]290 src_fd = open_or_warn(source, O_RDONLY);
291 if (src_fd < 0)
292 return -1;
[821]293
[2725]294 /* Do not try to open with weird mode fields */
295 new_mode = source_stat.st_mode;
296 if (!S_ISREG(source_stat.st_mode))
297 new_mode = 0666;
298
299 // POSIX way is a security problem versus (sym)link attacks
300 if (!ENABLE_FEATURE_NON_POSIX_CP) {
301 dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
302 } else { /* safe way: */
303 dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
304 }
[1765]305 if (dst_fd == -1) {
306 ovr = ask_and_unlink(dest, flags);
307 if (ovr <= 0) {
308 close(src_fd);
309 return ovr;
[821]310 }
[1765]311 /* It shouldn't exist. If it exists, do not open (symlink attack?) */
[2725]312 dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
[1765]313 if (dst_fd < 0) {
[821]314 close(src_fd);
[1765]315 return -1;
[821]316 }
317 }
318
[1765]319#if ENABLE_SELINUX
[2725]320 if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
[1765]321 && is_selinux_enabled() > 0
322 ) {
323 security_context_t con;
324 if (getfscreatecon(&con) == -1) {
325 bb_perror_msg("getfscreatecon");
[821]326 return -1;
327 }
[1765]328 if (con) {
329 if (setfilecon(dest, con) == -1) {
330 bb_perror_msg("setfilecon:%s,%s", dest, con);
331 freecon(con);
332 return -1;
333 }
334 freecon(con);
[821]335 }
336 }
[1765]337#endif
338 if (bb_copyfd_eof(src_fd, dst_fd) == -1)
339 retval = -1;
[2725]340 /* Careful with writing... */
[1765]341 if (close(dst_fd) < 0) {
[2725]342 bb_perror_msg("error writing to '%s'", dest);
[1765]343 retval = -1;
344 }
345 /* ...but read size is already checked by bb_copyfd_eof */
346 close(src_fd);
[2725]347 /* "cp /dev/something new_file" should not
348 * copy mode of /dev/something */
349 if (!S_ISREG(source_stat.st_mode))
350 return retval;
[1765]351 goto preserve_mode_ugid_time;
352 }
[2725]353 dont_cat:
[821]354
[1765]355 /* Source is a symlink or a special file */
356 /* We are lazy here, a bit lax with races... */
357 if (dest_exists) {
358 errno = EEXIST;
359 ovr = ask_and_unlink(dest, flags);
360 if (ovr <= 0)
361 return ovr;
362 }
363 if (S_ISLNK(source_stat.st_mode)) {
364 char *lpath = xmalloc_readlink_or_warn(source);
365 if (lpath) {
366 int r = symlink(lpath, dest);
367 free(lpath);
368 if (r < 0) {
[2725]369 bb_perror_msg("can't create symlink '%s'", dest);
[821]370 return -1;
371 }
372 if (flags & FILEUTILS_PRESERVE_STATUS)
373 if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0)
[2725]374 bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
[821]375 }
[1765]376 /* _Not_ jumping to preserve_mode_ugid_time:
377 * symlinks don't have those */
378 return 0;
379 }
380 if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode)
381 || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode)
382 ) {
383 if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) {
[2725]384 bb_perror_msg("can't create '%s'", dest);
[1765]385 return -1;
386 }
[821]387 } else {
[1765]388 bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode);
[821]389 return -1;
390 }
391
[1765]392 preserve_mode_ugid_time:
[821]393
[1765]394 if (flags & FILEUTILS_PRESERVE_STATUS
395 /* Cannot happen: */
396 /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */
397 ) {
[2725]398 struct timeval times[2];
[821]399
[2725]400 times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime;
401 times[1].tv_usec = times[0].tv_usec = 0;
[1765]402 /* BTW, utimes sets usec-precision time - just FYI */
[2725]403 if (utimes(dest, times) < 0)
404 bb_perror_msg("can't preserve %s of '%s'", "times", dest);
[821]405 if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) {
406 source_stat.st_mode &= ~(S_ISUID | S_ISGID);
[2725]407 bb_perror_msg("can't preserve %s of '%s'", "ownership", dest);
[821]408 }
409 if (chmod(dest, source_stat.st_mode) < 0)
[2725]410 bb_perror_msg("can't preserve %s of '%s'", "permissions", dest);
[821]411 }
412
[3621]413 if (flags & FILEUTILS_VERBOSE) {
414 printf("'%s' -> '%s'\n", source, dest);
415 }
416
[1765]417 return retval;
[821]418}
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