Contents of /trunk/mkinitrd-magellan/busybox/archival/libunarchive/get_header_tar.c
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Fri Apr 24 18:33:46 2009 UTC (15 years ago) by niro
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File size: 11857 byte(s)
Fri Apr 24 18:33:46 2009 UTC (15 years ago) by niro
File MIME type: text/plain
File size: 11857 byte(s)
-updated to busybox-1.13.4
1 | /* vi: set sw=4 ts=4: */ |
2 | /* Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
3 | * |
4 | * FIXME: |
5 | * In privileged mode if uname and gname map to a uid and gid then use the |
6 | * mapped value instead of the uid/gid values in tar header |
7 | * |
8 | * References: |
9 | * GNU tar and star man pages, |
10 | * Opengroup's ustar interchange format, |
11 | * http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html |
12 | */ |
13 | |
14 | #include "libbb.h" |
15 | #include "unarchive.h" |
16 | |
17 | /* NB: _DESTROYS_ str[len] character! */ |
18 | static unsigned long long getOctal(char *str, int len) |
19 | { |
20 | unsigned long long v; |
21 | /* NB: leading spaces are allowed. Using strtoull to handle that. |
22 | * The downside is that we accept e.g. "-123" too :) |
23 | */ |
24 | str[len] = '\0'; |
25 | v = strtoull(str, &str, 8); |
26 | if (*str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY || *str != ' ')) |
27 | bb_error_msg_and_die("corrupted octal value in tar header"); |
28 | return v; |
29 | } |
30 | #define GET_OCTAL(a) getOctal((a), sizeof(a)) |
31 | |
32 | void BUG_tar_header_size(void); |
33 | char FAST_FUNC get_header_tar(archive_handle_t *archive_handle) |
34 | { |
35 | file_header_t *file_header = archive_handle->file_header; |
36 | struct { |
37 | /* ustar header, Posix 1003.1 */ |
38 | char name[100]; /* 0-99 */ |
39 | char mode[8]; /* 100-107 */ |
40 | char uid[8]; /* 108-115 */ |
41 | char gid[8]; /* 116-123 */ |
42 | char size[12]; /* 124-135 */ |
43 | char mtime[12]; /* 136-147 */ |
44 | char chksum[8]; /* 148-155 */ |
45 | char typeflag; /* 156-156 */ |
46 | char linkname[100]; /* 157-256 */ |
47 | /* POSIX: "ustar" NUL "00" */ |
48 | /* GNU tar: "ustar " NUL */ |
49 | /* Normally it's defined as magic[6] followed by |
50 | * version[2], but we put them together to simplify code |
51 | */ |
52 | char magic[8]; /* 257-264 */ |
53 | char uname[32]; /* 265-296 */ |
54 | char gname[32]; /* 297-328 */ |
55 | char devmajor[8]; /* 329-336 */ |
56 | char devminor[8]; /* 337-344 */ |
57 | char prefix[155]; /* 345-499 */ |
58 | char padding[12]; /* 500-512 */ |
59 | } tar; |
60 | char *cp; |
61 | int i, sum_u, sum; |
62 | #if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY |
63 | int sum_s; |
64 | #endif |
65 | int parse_names; |
66 | |
67 | /* Our "private data" */ |
68 | #define p_end (*(smallint *)(&archive_handle->ah_priv[0])) |
69 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
70 | #define p_longname (*(char* *)(&archive_handle->ah_priv[1])) |
71 | #define p_linkname (*(char* *)(&archive_handle->ah_priv[2])) |
72 | #else |
73 | #define p_longname 0 |
74 | #define p_linkname 0 |
75 | #endif |
76 | // if (!archive_handle->ah_priv_inited) { |
77 | // archive_handle->ah_priv_inited = 1; |
78 | // p_end = 0; |
79 | // USE_FEATURE_TAR_GNU_EXTENSIONS(p_longname = NULL;) |
80 | // USE_FEATURE_TAR_GNU_EXTENSIONS(p_linkname = NULL;) |
81 | // } |
82 | |
83 | if (sizeof(tar) != 512) |
84 | BUG_tar_header_size(); |
85 | |
86 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
87 | again: |
88 | #endif |
89 | /* Align header */ |
90 | data_align(archive_handle, 512); |
91 | |
92 | again_after_align: |
93 | |
94 | #if ENABLE_DESKTOP || ENABLE_FEATURE_TAR_AUTODETECT |
95 | /* to prevent misdetection of bz2 sig */ |
96 | *(uint32_t*)(&tar) = 0; |
97 | i = full_read(archive_handle->src_fd, &tar, 512); |
98 | /* If GNU tar sees EOF in above read, it says: |
99 | * "tar: A lone zero block at N", where N = kilobyte |
100 | * where EOF was met (not EOF block, actual EOF!), |
101 | * and exits with EXIT_SUCCESS. |
102 | * We will mimic exit(EXIT_SUCCESS), although we will not mimic |
103 | * the message and we don't check whether we indeed |
104 | * saw zero block directly before this. */ |
105 | if (i == 0) { |
106 | xfunc_error_retval = 0; |
107 | short_read: |
108 | bb_error_msg_and_die("short read"); |
109 | } |
110 | if (i != 512) { |
111 | USE_FEATURE_TAR_AUTODETECT(goto autodetect;) |
112 | goto short_read; |
113 | } |
114 | |
115 | #else |
116 | i = 512; |
117 | xread(archive_handle->src_fd, &tar, i); |
118 | #endif |
119 | archive_handle->offset += i; |
120 | |
121 | /* If there is no filename its an empty header */ |
122 | if (tar.name[0] == 0 && tar.prefix[0] == 0) { |
123 | if (p_end) { |
124 | /* Second consecutive empty header - end of archive. |
125 | * Read until the end to empty the pipe from gz or bz2 |
126 | */ |
127 | while (full_read(archive_handle->src_fd, &tar, 512) == 512) |
128 | continue; |
129 | return EXIT_FAILURE; |
130 | } |
131 | p_end = 1; |
132 | return EXIT_SUCCESS; |
133 | } |
134 | p_end = 0; |
135 | |
136 | /* Check header has valid magic, "ustar" is for the proper tar, |
137 | * five NULs are for the old tar format */ |
138 | if (strncmp(tar.magic, "ustar", 5) != 0 |
139 | && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY |
140 | || memcmp(tar.magic, "\0\0\0\0", 5) != 0) |
141 | ) { |
142 | #if ENABLE_FEATURE_TAR_AUTODETECT |
143 | char FAST_FUNC (*get_header_ptr)(archive_handle_t *); |
144 | |
145 | autodetect: |
146 | /* tar gz/bz autodetect: check for gz/bz2 magic. |
147 | * If we see the magic, and it is the very first block, |
148 | * we can switch to get_header_tar_gz/bz2/lzma(). |
149 | * Needs seekable fd. I wish recv(MSG_PEEK) works |
150 | * on any fd... */ |
151 | #if ENABLE_FEATURE_SEAMLESS_GZ |
152 | if (tar.name[0] == 0x1f && tar.name[1] == (char)0x8b) { /* gzip */ |
153 | get_header_ptr = get_header_tar_gz; |
154 | } else |
155 | #endif |
156 | #if ENABLE_FEATURE_SEAMLESS_BZ2 |
157 | if (tar.name[0] == 'B' && tar.name[1] == 'Z' |
158 | && tar.name[2] == 'h' && isdigit(tar.name[3]) |
159 | ) { /* bzip2 */ |
160 | get_header_ptr = get_header_tar_bz2; |
161 | } else |
162 | #endif |
163 | goto err; |
164 | /* Two different causes for lseek() != 0: |
165 | * unseekable fd (would like to support that too, but...), |
166 | * or not first block (false positive, it's not .gz/.bz2!) */ |
167 | if (lseek(archive_handle->src_fd, -i, SEEK_CUR) != 0) |
168 | goto err; |
169 | while (get_header_ptr(archive_handle) == EXIT_SUCCESS) |
170 | continue; |
171 | return EXIT_FAILURE; |
172 | err: |
173 | #endif /* FEATURE_TAR_AUTODETECT */ |
174 | bb_error_msg_and_die("invalid tar magic"); |
175 | } |
176 | |
177 | /* Do checksum on headers. |
178 | * POSIX says that checksum is done on unsigned bytes, but |
179 | * Sun and HP-UX gets it wrong... more details in |
180 | * GNU tar source. */ |
181 | #if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY |
182 | sum_s = ' ' * sizeof(tar.chksum); |
183 | #endif |
184 | sum_u = ' ' * sizeof(tar.chksum); |
185 | for (i = 0; i < 148; i++) { |
186 | sum_u += ((unsigned char*)&tar)[i]; |
187 | #if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY |
188 | sum_s += ((signed char*)&tar)[i]; |
189 | #endif |
190 | } |
191 | for (i = 156; i < 512; i++) { |
192 | sum_u += ((unsigned char*)&tar)[i]; |
193 | #if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY |
194 | sum_s += ((signed char*)&tar)[i]; |
195 | #endif |
196 | } |
197 | #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY |
198 | sum = strtoul(tar.chksum, &cp, 8); |
199 | if ((*cp && *cp != ' ') |
200 | || (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) |
201 | ) { |
202 | bb_error_msg_and_die("invalid tar header checksum"); |
203 | } |
204 | #else |
205 | /* This field does not need special treatment (getOctal) */ |
206 | sum = xstrtoul(tar.chksum, 8); |
207 | if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) { |
208 | bb_error_msg_and_die("invalid tar header checksum"); |
209 | } |
210 | #endif |
211 | |
212 | /* 0 is reserved for high perf file, treat as normal file */ |
213 | if (!tar.typeflag) tar.typeflag = '0'; |
214 | parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7'); |
215 | |
216 | /* getOctal trashes subsequent field, therefore we call it |
217 | * on fields in reverse order */ |
218 | if (tar.devmajor[0]) { |
219 | char t = tar.prefix[0]; |
220 | /* we trash prefix[0] here, but we DO need it later! */ |
221 | unsigned minor = GET_OCTAL(tar.devminor); |
222 | unsigned major = GET_OCTAL(tar.devmajor); |
223 | file_header->device = makedev(major, minor); |
224 | tar.prefix[0] = t; |
225 | } |
226 | file_header->link_target = NULL; |
227 | if (!p_linkname && parse_names && tar.linkname[0]) { |
228 | file_header->link_target = xstrndup(tar.linkname, sizeof(tar.linkname)); |
229 | /* FIXME: what if we have non-link object with link_target? */ |
230 | /* Will link_target be free()ed? */ |
231 | } |
232 | #if ENABLE_FEATURE_TAR_UNAME_GNAME |
233 | file_header->uname = tar.uname[0] ? xstrndup(tar.uname, sizeof(tar.uname)) : NULL; |
234 | file_header->gname = tar.gname[0] ? xstrndup(tar.gname, sizeof(tar.gname)) : NULL; |
235 | #endif |
236 | file_header->mtime = GET_OCTAL(tar.mtime); |
237 | file_header->size = GET_OCTAL(tar.size); |
238 | file_header->gid = GET_OCTAL(tar.gid); |
239 | file_header->uid = GET_OCTAL(tar.uid); |
240 | /* Set bits 0-11 of the files mode */ |
241 | file_header->mode = 07777 & GET_OCTAL(tar.mode); |
242 | |
243 | file_header->name = NULL; |
244 | if (!p_longname && parse_names) { |
245 | /* we trash mode[0] here, it's ok */ |
246 | //tar.name[sizeof(tar.name)] = '\0'; - gcc 4.3.0 would complain |
247 | tar.mode[0] = '\0'; |
248 | if (tar.prefix[0]) { |
249 | /* and padding[0] */ |
250 | //tar.prefix[sizeof(tar.prefix)] = '\0'; - gcc 4.3.0 would complain |
251 | tar.padding[0] = '\0'; |
252 | file_header->name = concat_path_file(tar.prefix, tar.name); |
253 | } else |
254 | file_header->name = xstrdup(tar.name); |
255 | } |
256 | |
257 | /* Set bits 12-15 of the files mode */ |
258 | /* (typeflag was not trashed because chksum does not use getOctal) */ |
259 | switch (tar.typeflag) { |
260 | /* busybox identifies hard links as being regular files with 0 size and a link name */ |
261 | case '1': |
262 | file_header->mode |= S_IFREG; |
263 | break; |
264 | case '7': |
265 | /* case 0: */ |
266 | case '0': |
267 | #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY |
268 | if (last_char_is(file_header->name, '/')) { |
269 | goto set_dir; |
270 | } |
271 | #endif |
272 | file_header->mode |= S_IFREG; |
273 | break; |
274 | case '2': |
275 | file_header->mode |= S_IFLNK; |
276 | /* have seen tarballs with size field containing |
277 | * the size of the link target's name */ |
278 | size0: |
279 | file_header->size = 0; |
280 | break; |
281 | case '3': |
282 | file_header->mode |= S_IFCHR; |
283 | goto size0; /* paranoia */ |
284 | case '4': |
285 | file_header->mode |= S_IFBLK; |
286 | goto size0; |
287 | case '5': |
288 | USE_FEATURE_TAR_OLDGNU_COMPATIBILITY(set_dir:) |
289 | file_header->mode |= S_IFDIR; |
290 | goto size0; |
291 | case '6': |
292 | file_header->mode |= S_IFIFO; |
293 | goto size0; |
294 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
295 | case 'L': |
296 | /* free: paranoia: tar with several consecutive longnames */ |
297 | free(p_longname); |
298 | /* For paranoia reasons we allocate extra NUL char */ |
299 | p_longname = xzalloc(file_header->size + 1); |
300 | /* We read ASCIZ string, including NUL */ |
301 | xread(archive_handle->src_fd, p_longname, file_header->size); |
302 | archive_handle->offset += file_header->size; |
303 | /* return get_header_tar(archive_handle); */ |
304 | /* gcc 4.1.1 didn't optimize it into jump */ |
305 | /* so we will do it ourself, this also saves stack */ |
306 | goto again; |
307 | case 'K': |
308 | free(p_linkname); |
309 | p_linkname = xzalloc(file_header->size + 1); |
310 | xread(archive_handle->src_fd, p_linkname, file_header->size); |
311 | archive_handle->offset += file_header->size; |
312 | /* return get_header_tar(archive_handle); */ |
313 | goto again; |
314 | case 'D': /* GNU dump dir */ |
315 | case 'M': /* Continuation of multi volume archive */ |
316 | case 'N': /* Old GNU for names > 100 characters */ |
317 | case 'S': /* Sparse file */ |
318 | case 'V': /* Volume header */ |
319 | #endif |
320 | case 'g': /* pax global header */ |
321 | case 'x': { /* pax extended header */ |
322 | off_t sz; |
323 | bb_error_msg("warning: skipping header '%c'", tar.typeflag); |
324 | sz = (file_header->size + 511) & ~(off_t)511; |
325 | archive_handle->offset += sz; |
326 | sz >>= 9; /* sz /= 512 but w/o contortions for signed div */ |
327 | while (sz--) |
328 | xread(archive_handle->src_fd, &tar, 512); |
329 | /* return get_header_tar(archive_handle); */ |
330 | goto again_after_align; |
331 | } |
332 | default: |
333 | bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag); |
334 | } |
335 | |
336 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
337 | if (p_longname) { |
338 | file_header->name = p_longname; |
339 | p_longname = NULL; |
340 | } |
341 | if (p_linkname) { |
342 | file_header->link_target = p_linkname; |
343 | p_linkname = NULL; |
344 | } |
345 | #endif |
346 | if (strncmp(file_header->name, "/../"+1, 3) == 0 |
347 | || strstr(file_header->name, "/../") |
348 | ) { |
349 | bb_error_msg_and_die("name with '..' encountered: '%s'", |
350 | file_header->name); |
351 | } |
352 | |
353 | /* Strip trailing '/' in directories */ |
354 | /* Must be done after mode is set as '/' is used to check if it's a directory */ |
355 | cp = last_char_is(file_header->name, '/'); |
356 | |
357 | if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) { |
358 | archive_handle->action_header(/*archive_handle->*/ file_header); |
359 | /* Note that we kill the '/' only after action_header() */ |
360 | /* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */ |
361 | if (cp) *cp = '\0'; |
362 | archive_handle->ah_flags |= ARCHIVE_EXTRACT_QUIET; |
363 | archive_handle->action_data(archive_handle); |
364 | llist_add_to(&(archive_handle->passed), file_header->name); |
365 | } else { |
366 | data_skip(archive_handle); |
367 | free(file_header->name); |
368 | } |
369 | archive_handle->offset += file_header->size; |
370 | |
371 | free(file_header->link_target); |
372 | /* Do not free(file_header->name)! (why?) */ |
373 | #if ENABLE_FEATURE_TAR_UNAME_GNAME |
374 | free(file_header->uname); |
375 | free(file_header->gname); |
376 | #endif |
377 | return EXIT_SUCCESS; |
378 | } |