blob: 23c0f8320b86f19f5d1a478368843340bd1bf51b
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> |
6 | * SELinux support by Yuichi Nakamura <ynakam@hitachisoft.jp> |
7 | * |
8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
9 | */ |
10 | #include "libbb.h" |
11 | |
12 | // FEATURE_NON_POSIX_CP: |
13 | // |
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: |
18 | // If dest is a (sym)link, we overwrite link destination! |
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 | |
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 */ |
26 | static int ask_and_unlink(const char *dest, int flags) |
27 | { |
28 | int e = errno; |
29 | |
30 | #if !ENABLE_FEATURE_NON_POSIX_CP |
31 | if (!(flags & (FILEUTILS_FORCE|FILEUTILS_INTERACTIVE))) { |
32 | /* Either it exists, or the *path* doesnt exist */ |
33 | bb_perror_msg("can't create '%s'", dest); |
34 | return -1; |
35 | } |
36 | #endif |
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. |
43 | |
44 | /* TODO: maybe we should do it only if ctty is present? */ |
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()) |
52 | return 0; /* not allowed to overwrite */ |
53 | } |
54 | if (unlink(dest) < 0) { |
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 */ |
66 | } |
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 |
72 | return 1; /* ok (to try again) */ |
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 | */ |
80 | int FAST_FUNC copy_file(const char *source, const char *dest, int flags) |
81 | { |
82 | /* This is a recursive function, try to minimize stack usage */ |
83 | /* NB: each struct stat is ~100 bytes */ |
84 | struct stat source_stat; |
85 | struct stat dest_stat; |
86 | smallint retval = 0; |
87 | smallint dest_exists = 0; |
88 | smallint ovr; |
89 | |
90 | /* Inverse of cp -d ("cp without -d") */ |
91 | #define FLAGS_DEREF (flags & (FILEUTILS_DEREFERENCE + FILEUTILS_DEREFERENCE_L0)) |
92 | |
93 | if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) { |
94 | /* This may be a dangling symlink. |
95 | * Making [sym]links to dangling symlinks works, so... */ |
96 | if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) |
97 | goto make_links; |
98 | bb_perror_msg("can't stat '%s'", source); |
99 | return -1; |
100 | } |
101 | |
102 | if (lstat(dest, &dest_stat) < 0) { |
103 | if (errno != ENOENT) { |
104 | bb_perror_msg("can't stat '%s'", dest); |
105 | return -1; |
106 | } |
107 | } else { |
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); |
112 | return -1; |
113 | } |
114 | dest_exists = 1; |
115 | } |
116 | |
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) { |
122 | bb_perror_msg("can't set setfscreatecon %s", con); |
123 | freecon(con); |
124 | return -1; |
125 | } |
126 | } else if (errno == ENOTSUP || errno == ENODATA) { |
127 | setfscreatecon_or_die(NULL); |
128 | } else { |
129 | bb_perror_msg("can't lgetfilecon %s", source); |
130 | return -1; |
131 | } |
132 | } |
133 | #endif |
134 | |
135 | if (S_ISDIR(source_stat.st_mode)) { |
136 | DIR *dp; |
137 | const char *tp; |
138 | struct dirent *d; |
139 | mode_t saved_umask = 0; |
140 | |
141 | if (!(flags & FILEUTILS_RECUR)) { |
142 | bb_error_msg("omitting directory '%s'", source); |
143 | return -1; |
144 | } |
145 | |
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 | |
155 | if (dest_exists) { |
156 | if (!S_ISDIR(dest_stat.st_mode)) { |
157 | bb_error_msg("target '%s' is not a directory", dest); |
158 | return -1; |
159 | } |
160 | /* race here: user can substitute a symlink between |
161 | * this check and actual creation of files inside dest */ |
162 | } else { |
163 | /* Create DEST */ |
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; |
170 | /* Allow owner to access new dir (at least for now) */ |
171 | mode |= S_IRWXU; |
172 | if (mkdir(dest, mode) < 0) { |
173 | umask(saved_umask); |
174 | bb_perror_msg("can't create directory '%s'", dest); |
175 | return -1; |
176 | } |
177 | umask(saved_umask); |
178 | /* need stat info for add_to_ino_dev_hashtable */ |
179 | if (lstat(dest, &dest_stat) < 0) { |
180 | bb_perror_msg("can't stat '%s'", dest); |
181 | return -1; |
182 | } |
183 | } |
184 | /* remember (dev,inode) of each created dir. |
185 | * NULL: name is not remembered */ |
186 | add_to_ino_dev_hashtable(&dest_stat, NULL); |
187 | |
188 | /* Recursively copy files in SOURCE */ |
189 | dp = opendir(source); |
190 | if (dp == NULL) { |
191 | retval = -1; |
192 | goto preserve_mode_ugid_time; |
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); |
199 | if (new_source == NULL) |
200 | continue; |
201 | new_dest = concat_path_file(dest, d->d_name); |
202 | if (copy_file(new_source, new_dest, flags & ~FILEUTILS_DEREFERENCE_L0) < 0) |
203 | retval = -1; |
204 | free(new_source); |
205 | free(new_dest); |
206 | } |
207 | closedir(dp); |
208 | |
209 | if (!dest_exists |
210 | && chmod(dest, source_stat.st_mode & ~saved_umask) < 0 |
211 | ) { |
212 | bb_perror_msg("can't preserve %s of '%s'", "permissions", dest); |
213 | /* retval = -1; - WRONG! copy *WAS* made */ |
214 | } |
215 | goto preserve_mode_ugid_time; |
216 | } |
217 | |
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 | |
234 | if (flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) { |
235 | int (*lf)(const char *oldpath, const char *newpath); |
236 | make_links: |
237 | /* Hmm... maybe |
238 | * if (DEREF && MAKE_SOFTLINK) source = realpath(source) ? |
239 | * (but realpath returns NULL on dangling symlinks...) */ |
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) { |
246 | bb_perror_msg("can't create link '%s'", dest); |
247 | return -1; |
248 | } |
249 | } |
250 | /* _Not_ jumping to preserve_mode_ugid_time: |
251 | * (sym)links don't have those */ |
252 | return 0; |
253 | } |
254 | |
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: */ |
261 | /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */ |
262 | ) { |
263 | int src_fd; |
264 | int dst_fd; |
265 | mode_t new_mode; |
266 | |
267 | if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) { |
268 | /* "cp -d symlink dst": create a link */ |
269 | goto dont_cat; |
270 | } |
271 | |
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) { |
281 | bb_perror_msg("can't create link '%s'", dest); |
282 | return -1; |
283 | } |
284 | } |
285 | return 0; |
286 | } |
287 | add_to_ino_dev_hashtable(&source_stat, dest); |
288 | } |
289 | |
290 | src_fd = open_or_warn(source, O_RDONLY); |
291 | if (src_fd < 0) |
292 | return -1; |
293 | |
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 | if (ENABLE_FEATURE_NON_POSIX_CP || (flags & FILEUTILS_INTERACTIVE)) { |
300 | /* |
301 | * O_CREAT|O_EXCL: require that file did not exist before creation |
302 | */ |
303 | dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode); |
304 | } else { /* POSIX, and not "cp -i" */ |
305 | /* |
306 | * O_CREAT|O_TRUNC: create, or truncate (security problem versus (sym)link attacks) |
307 | */ |
308 | dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode); |
309 | } |
310 | if (dst_fd == -1) { |
311 | ovr = ask_and_unlink(dest, flags); |
312 | if (ovr <= 0) { |
313 | close(src_fd); |
314 | return ovr; |
315 | } |
316 | /* It shouldn't exist. If it exists, do not open (symlink attack?) */ |
317 | dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode); |
318 | if (dst_fd < 0) { |
319 | close(src_fd); |
320 | return -1; |
321 | } |
322 | } |
323 | |
324 | #if ENABLE_SELINUX |
325 | if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT)) |
326 | && is_selinux_enabled() > 0 |
327 | ) { |
328 | security_context_t con; |
329 | if (getfscreatecon(&con) == -1) { |
330 | bb_perror_msg("getfscreatecon"); |
331 | return -1; |
332 | } |
333 | if (con) { |
334 | if (setfilecon(dest, con) == -1) { |
335 | bb_perror_msg("setfilecon:%s,%s", dest, con); |
336 | freecon(con); |
337 | return -1; |
338 | } |
339 | freecon(con); |
340 | } |
341 | } |
342 | #endif |
343 | if (bb_copyfd_eof(src_fd, dst_fd) == -1) |
344 | retval = -1; |
345 | /* Careful with writing... */ |
346 | if (close(dst_fd) < 0) { |
347 | bb_perror_msg("error writing to '%s'", dest); |
348 | retval = -1; |
349 | } |
350 | /* ...but read size is already checked by bb_copyfd_eof */ |
351 | close(src_fd); |
352 | /* "cp /dev/something new_file" should not |
353 | * copy mode of /dev/something */ |
354 | if (!S_ISREG(source_stat.st_mode)) |
355 | return retval; |
356 | goto preserve_mode_ugid_time; |
357 | } |
358 | dont_cat: |
359 | |
360 | /* Source is a symlink or a special file */ |
361 | /* We are lazy here, a bit lax with races... */ |
362 | if (dest_exists) { |
363 | errno = EEXIST; |
364 | ovr = ask_and_unlink(dest, flags); |
365 | if (ovr <= 0) |
366 | return ovr; |
367 | } |
368 | if (S_ISLNK(source_stat.st_mode)) { |
369 | char *lpath = xmalloc_readlink_or_warn(source); |
370 | if (lpath) { |
371 | int r = symlink(lpath, dest); |
372 | free(lpath); |
373 | if (r < 0) { |
374 | bb_perror_msg("can't create symlink '%s'", dest); |
375 | return -1; |
376 | } |
377 | if (flags & FILEUTILS_PRESERVE_STATUS) |
378 | if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0) |
379 | bb_perror_msg("can't preserve %s of '%s'", "ownership", dest); |
380 | } |
381 | /* _Not_ jumping to preserve_mode_ugid_time: |
382 | * symlinks don't have those */ |
383 | goto verb_and_exit; |
384 | } |
385 | if (S_ISBLK(source_stat.st_mode) || S_ISCHR(source_stat.st_mode) |
386 | || S_ISSOCK(source_stat.st_mode) || S_ISFIFO(source_stat.st_mode) |
387 | ) { |
388 | if (mknod(dest, source_stat.st_mode, source_stat.st_rdev) < 0) { |
389 | bb_perror_msg("can't create '%s'", dest); |
390 | return -1; |
391 | } |
392 | } else { |
393 | bb_error_msg("unrecognized file '%s' with mode %x", source, source_stat.st_mode); |
394 | return -1; |
395 | } |
396 | |
397 | preserve_mode_ugid_time: |
398 | |
399 | if (flags & FILEUTILS_PRESERVE_STATUS |
400 | /* Cannot happen: */ |
401 | /* && !(flags & (FILEUTILS_MAKE_SOFTLINK|FILEUTILS_MAKE_HARDLINK)) */ |
402 | ) { |
403 | struct timeval times[2]; |
404 | |
405 | times[1].tv_sec = times[0].tv_sec = source_stat.st_mtime; |
406 | times[1].tv_usec = times[0].tv_usec = 0; |
407 | /* BTW, utimes sets usec-precision time - just FYI */ |
408 | if (utimes(dest, times) < 0) |
409 | bb_perror_msg("can't preserve %s of '%s'", "times", dest); |
410 | if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) { |
411 | source_stat.st_mode &= ~(S_ISUID | S_ISGID); |
412 | bb_perror_msg("can't preserve %s of '%s'", "ownership", dest); |
413 | } |
414 | if (chmod(dest, source_stat.st_mode) < 0) |
415 | bb_perror_msg("can't preserve %s of '%s'", "permissions", dest); |
416 | } |
417 | |
418 | verb_and_exit: |
419 | if (flags & FILEUTILS_VERBOSE) { |
420 | printf("'%s' -> '%s'\n", source, dest); |
421 | } |
422 | |
423 | return retval; |
424 | } |
425 |