source: MondoRescue/branches/2.2.9/mindi-busybox/archival/libunarchive/get_header_tar.c@ 3320

Last change on this file since 3320 was 3320, checked in by Bruno Cornec, 9 years ago
  • Re-add (thanks git BTW) the 2.2.9 branch which had been destroyed in the move to 3.0
  • Property svn:eol-style set to native
File size: 8.8 KB
Line 
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#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
18static char *longname;
19static char *linkname;
20#else
21enum {
22 longname = 0,
23 linkname = 0,
24};
25#endif
26
27/* NB: _DESTROYS_ str[len] character! */
28static unsigned long long getOctal(char *str, int len)
29{
30 unsigned long long v;
31 /* Actually, tar header allows leading spaces also.
32 * Oh well, we will be liberal and skip this...
33 * The only downside probably is that we allow "-123" too :)
34 if (*str < '0' || *str > '7')
35 bb_error_msg_and_die("corrupted octal value in tar header");
36 */
37 str[len] = '\0';
38 v = strtoull(str, &str, 8);
39 if (*str && (!ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY || *str != ' '))
40 bb_error_msg_and_die("corrupted octal value in tar header");
41 return v;
42}
43#define GET_OCTAL(a) getOctal((a), sizeof(a))
44
45void BUG_tar_header_size(void);
46char get_header_tar(archive_handle_t *archive_handle)
47{
48 static smallint end;
49
50 file_header_t *file_header = archive_handle->file_header;
51 struct {
52 /* ustar header, Posix 1003.1 */
53 char name[100]; /* 0-99 */
54 char mode[8]; /* 100-107 */
55 char uid[8]; /* 108-115 */
56 char gid[8]; /* 116-123 */
57 char size[12]; /* 124-135 */
58 char mtime[12]; /* 136-147 */
59 char chksum[8]; /* 148-155 */
60 char typeflag; /* 156-156 */
61 char linkname[100]; /* 157-256 */
62 char magic[6]; /* 257-262 */
63 char version[2]; /* 263-264 */
64 char uname[32]; /* 265-296 */
65 char gname[32]; /* 297-328 */
66 char devmajor[8]; /* 329-336 */
67 char devminor[8]; /* 337-344 */
68 char prefix[155]; /* 345-499 */
69 char padding[12]; /* 500-512 */
70 } tar;
71 char *cp;
72 int i, sum_u, sum;
73#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
74 int sum_s;
75#endif
76 int parse_names;
77
78 if (sizeof(tar) != 512)
79 BUG_tar_header_size();
80
81#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
82 again:
83#endif
84 /* Align header */
85 data_align(archive_handle, 512);
86
87 again_after_align:
88
89 xread(archive_handle->src_fd, &tar, 512);
90 archive_handle->offset += 512;
91
92 /* If there is no filename its an empty header */
93 if (tar.name[0] == 0) {
94 if (end) {
95 /* This is the second consecutive empty header! End of archive!
96 * Read until the end to empty the pipe from gz or bz2
97 */
98 while (full_read(archive_handle->src_fd, &tar, 512) == 512)
99 /* repeat */;
100 return EXIT_FAILURE;
101 }
102 end = 1;
103 return EXIT_SUCCESS;
104 }
105 end = 0;
106
107 /* Check header has valid magic, "ustar" is for the proper tar
108 * 0's are for the old tar format
109 */
110 if (strncmp(tar.magic, "ustar", 5) != 0) {
111#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
112 if (memcmp(tar.magic, "\0\0\0\0", 5) != 0)
113#endif
114 bb_error_msg_and_die("invalid tar magic");
115 }
116
117 /* Do checksum on headers.
118 * POSIX says that checksum is done on unsigned bytes, but
119 * Sun and HP-UX gets it wrong... more details in
120 * GNU tar source. */
121#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
122 sum_s = ' ' * sizeof(tar.chksum);
123#endif
124 sum_u = ' ' * sizeof(tar.chksum);
125 for (i = 0; i < 148; i++) {
126 sum_u += ((unsigned char*)&tar)[i];
127#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
128 sum_s += ((signed char*)&tar)[i];
129#endif
130 }
131 for (i = 156; i < 512; i++) {
132 sum_u += ((unsigned char*)&tar)[i];
133#if ENABLE_FEATURE_TAR_OLDSUN_COMPATIBILITY
134 sum_s += ((signed char*)&tar)[i];
135#endif
136 }
137#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
138 sum = strtoul(tar.chksum, &cp, 8);
139 if ((*cp && *cp != ' ')
140 || (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum))
141 ) {
142 bb_error_msg_and_die("invalid tar header checksum");
143 }
144#else
145 /* This field does not need special treatment (getOctal) */
146 sum = xstrtoul(tar.chksum, 8);
147 if (sum_u != sum USE_FEATURE_TAR_OLDSUN_COMPATIBILITY(&& sum_s != sum)) {
148 bb_error_msg_and_die("invalid tar header checksum");
149 }
150#endif
151
152 /* 0 is reserved for high perf file, treat as normal file */
153 if (!tar.typeflag) tar.typeflag = '0';
154 parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');
155
156 /* getOctal trashes subsequent field, therefore we call it
157 * on fields in reverse order */
158 if (tar.devmajor[0]) {
159 unsigned minor = GET_OCTAL(tar.devminor);
160 unsigned major = GET_OCTAL(tar.devmajor);
161 file_header->device = makedev(major, minor);
162 }
163 file_header->link_target = NULL;
164 if (!linkname && parse_names && tar.linkname[0]) {
165 /* we trash magic[0] here, it's ok */
166 tar.linkname[sizeof(tar.linkname)] = '\0';
167 file_header->link_target = xstrdup(tar.linkname);
168 /* FIXME: what if we have non-link object with link_target? */
169 /* Will link_target be free()ed? */
170 }
171 file_header->mtime = GET_OCTAL(tar.mtime);
172 file_header->size = GET_OCTAL(tar.size);
173 file_header->gid = GET_OCTAL(tar.gid);
174 file_header->uid = GET_OCTAL(tar.uid);
175 /* Set bits 0-11 of the files mode */
176 file_header->mode = 07777 & GET_OCTAL(tar.mode);
177
178 file_header->name = NULL;
179 if (!longname && parse_names) {
180 /* we trash mode[0] here, it's ok */
181 tar.name[sizeof(tar.name)] = '\0';
182 if (tar.prefix[0]) {
183 /* and padding[0] */
184 tar.prefix[sizeof(tar.prefix)] = '\0';
185 file_header->name = concat_path_file(tar.prefix, tar.name);
186 } else
187 file_header->name = xstrdup(tar.name);
188 }
189
190 /* Set bits 12-15 of the files mode */
191 /* (typeflag was not trashed because chksum does not use getOctal) */
192 switch (tar.typeflag) {
193 /* busybox identifies hard links as being regular files with 0 size and a link name */
194 case '1':
195 file_header->mode |= S_IFREG;
196 break;
197 case '7':
198 /* case 0: */
199 case '0':
200#if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
201 if (last_char_is(file_header->name, '/')) {
202 file_header->mode |= S_IFDIR;
203 } else
204#endif
205 file_header->mode |= S_IFREG;
206 break;
207 case '2':
208 file_header->mode |= S_IFLNK;
209 break;
210 case '3':
211 file_header->mode |= S_IFCHR;
212 break;
213 case '4':
214 file_header->mode |= S_IFBLK;
215 break;
216 case '5':
217 file_header->mode |= S_IFDIR;
218 break;
219 case '6':
220 file_header->mode |= S_IFIFO;
221 break;
222#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
223 case 'L':
224 /* free: paranoia: tar with several consecutive longnames */
225 free(longname);
226 /* For paranoia reasons we allocate extra NUL char */
227 longname = xzalloc(file_header->size + 1);
228 /* We read ASCIZ string, including NUL */
229 xread(archive_handle->src_fd, longname, file_header->size);
230 archive_handle->offset += file_header->size;
231 /* return get_header_tar(archive_handle); */
232 /* gcc 4.1.1 didn't optimize it into jump */
233 /* so we will do it ourself, this also saves stack */
234 goto again;
235 case 'K':
236 free(linkname);
237 linkname = xzalloc(file_header->size + 1);
238 xread(archive_handle->src_fd, linkname, file_header->size);
239 archive_handle->offset += file_header->size;
240 /* return get_header_tar(archive_handle); */
241 goto again;
242 case 'D': /* GNU dump dir */
243 case 'M': /* Continuation of multi volume archive */
244 case 'N': /* Old GNU for names > 100 characters */
245 case 'S': /* Sparse file */
246 case 'V': /* Volume header */
247#endif
248 case 'g': /* pax global header */
249 case 'x': { /* pax extended header */
250 off_t sz;
251 bb_error_msg("warning: skipping header '%c'", tar.typeflag);
252 sz = (file_header->size + 511) & ~(off_t)511;
253 archive_handle->offset += sz;
254 sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
255 while (sz--)
256 xread(archive_handle->src_fd, &tar, 512);
257 /* return get_header_tar(archive_handle); */
258 goto again_after_align;
259 }
260 default:
261 bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
262 }
263
264#if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
265 if (longname) {
266 file_header->name = longname;
267 longname = NULL;
268 }
269 if (linkname) {
270 file_header->link_target = linkname;
271 linkname = NULL;
272 }
273#endif
274 if (!strncmp(file_header->name, "/../"+1, 3)
275 || strstr(file_header->name, "/../")
276 ) {
277 bb_error_msg_and_die("name with '..' encountered: '%s'",
278 file_header->name);
279 }
280
281 /* Strip trailing '/' in directories */
282 /* Must be done after mode is set as '/' is used to check if it's a directory */
283 cp = last_char_is(file_header->name, '/');
284
285 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
286 archive_handle->action_header(archive_handle->file_header);
287 /* Note that we kill the '/' only after action_header() */
288 /* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
289 if (cp) *cp = '\0';
290 archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
291 archive_handle->action_data(archive_handle);
292 llist_add_to(&(archive_handle->passed), file_header->name);
293 } else {
294 data_skip(archive_handle);
295 free(file_header->name);
296 }
297 archive_handle->offset += file_header->size;
298
299 free(file_header->link_target);
300 /* Do not free(file_header->name)! */
301
302 return EXIT_SUCCESS;
303}
Note: See TracBrowser for help on using the repository browser.