1 /* vi: set sw=4 ts=4: */
2 /* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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
9 * GNU tar and star man pages,
10 * Opengroup's ustar interchange format,
11 * http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
15 #include "unarchive.h"
17 #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
18 static char *longname;
19 static char *linkname;
27 /* NB: _DESTROYS_ str[len] character! */
28 static unsigned long long getOctal(char *str, int len)
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");
38 v = strtoull(str, &str, 8);
40 bb_error_msg_and_die("corrupted octal value in tar header");
43 #define GET_OCTAL(a) getOctal((a), sizeof(a))
45 void BUG_tar_header_size(void);
46 char get_header_tar(archive_handle_t *archive_handle)
50 file_header_t *file_header = archive_handle->file_header;
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 */
75 if (sizeof(tar) != 512)
76 BUG_tar_header_size();
80 data_align(archive_handle, 512);
84 xread(archive_handle->src_fd, &tar, 512);
85 archive_handle->offset += 512;
87 /* If there is no filename its an empty header */
88 if (tar.name[0] == 0) {
90 /* This is the second consecutive empty header! End of archive!
91 * Read until the end to empty the pipe from gz or bz2
93 while (full_read(archive_handle->src_fd, &tar, 512) == 512)
102 /* Check header has valid magic, "ustar" is for the proper tar
103 * 0's are for the old tar format
105 if (strncmp(tar.magic, "ustar", 5) != 0) {
106 #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
107 if (memcmp(tar.magic, "\0\0\0\0", 5) != 0)
109 bb_error_msg_and_die("invalid tar magic");
111 /* Do checksum on headers */
112 sum = ' ' * sizeof(tar.chksum);
113 for (i = 0; i < 148 ; i++) {
114 sum += ((char*)&tar)[i];
116 for (i = 156; i < 512 ; i++) {
117 sum += ((char*)&tar)[i];
119 /* This field does not need special treatment (getOctal) */
120 if (sum != xstrtoul(tar.chksum, 8)) {
121 bb_error_msg_and_die("invalid tar header checksum");
124 /* 0 is reserved for high perf file, treat as normal file */
125 if (!tar.typeflag) tar.typeflag = '0';
126 parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7');
128 /* getOctal trashes subsequent field, therefore we call it
129 * on fields in reverse order */
130 if (tar.devmajor[0]) {
131 unsigned minor = GET_OCTAL(tar.devminor);
132 unsigned major = GET_OCTAL(tar.devmajor);
133 file_header->device = makedev(major, minor);
135 file_header->link_name = NULL;
136 if (!linkname && parse_names && tar.linkname[0]) {
137 /* we trash magic[0] here, it's ok */
138 tar.linkname[sizeof(tar.linkname)] = '\0';
139 file_header->link_name = xstrdup(tar.linkname);
140 /* FIXME: what if we have non-link object with link_name? */
141 /* Will link_name be free()ed? */
143 file_header->mtime = GET_OCTAL(tar.mtime);
144 file_header->size = GET_OCTAL(tar.size);
145 file_header->gid = GET_OCTAL(tar.gid);
146 file_header->uid = GET_OCTAL(tar.uid);
147 /* Set bits 0-11 of the files mode */
148 file_header->mode = 07777 & GET_OCTAL(tar.mode);
150 file_header->name = NULL;
151 if (!longname && parse_names) {
152 /* we trash mode[0] here, it's ok */
153 tar.name[sizeof(tar.name)] = '\0';
156 tar.prefix[sizeof(tar.prefix)] = '\0';
157 file_header->name = concat_path_file(tar.prefix, tar.name);
159 file_header->name = xstrdup(tar.name);
162 /* Set bits 12-15 of the files mode */
163 /* (typeflag was not trashed because chksum does not use getOctal) */
164 switch (tar.typeflag) {
165 /* busybox identifies hard links as being regular files with 0 size and a link name */
167 file_header->mode |= S_IFREG;
172 #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY
173 if (last_char_is(file_header->name, '/')) {
174 file_header->mode |= S_IFDIR;
177 file_header->mode |= S_IFREG;
180 file_header->mode |= S_IFLNK;
183 file_header->mode |= S_IFCHR;
186 file_header->mode |= S_IFBLK;
189 file_header->mode |= S_IFDIR;
192 file_header->mode |= S_IFIFO;
194 #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
196 /* free: paranoia: tar with several consecutive longnames */
198 /* For paranoia reasons we allocate extra NUL char */
199 longname = xzalloc(file_header->size + 1);
200 /* We read ASCIZ string, including NUL */
201 xread(archive_handle->src_fd, longname, file_header->size);
202 archive_handle->offset += file_header->size;
203 /* return get_header_tar(archive_handle); */
204 /* gcc 4.1.1 didn't optimize it into jump */
205 /* so we will do it ourself, this also saves stack */
209 linkname = xzalloc(file_header->size + 1);
210 xread(archive_handle->src_fd, linkname, file_header->size);
211 archive_handle->offset += file_header->size;
212 /* return get_header_tar(archive_handle); */
214 case 'D': /* GNU dump dir */
215 case 'M': /* Continuation of multi volume archive */
216 case 'N': /* Old GNU for names > 100 characters */
217 case 'S': /* Sparse file */
218 case 'V': /* Volume header */
220 case 'g': /* pax global header */
221 case 'x': { /* pax extended header */
223 bb_error_msg("warning: skipping header '%c'", tar.typeflag);
224 sz = (file_header->size + 511) & ~(off_t)511;
225 archive_handle->offset += sz;
226 sz >>= 9; /* sz /= 512 but w/o contortions for signed div */
228 xread(archive_handle->src_fd, &tar, 512);
229 /* return get_header_tar(archive_handle); */
230 goto again_after_align;
233 bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag);
236 #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS
238 file_header->name = longname;
242 file_header->link_name = linkname;
246 if (!strncmp(file_header->name, "/../"+1, 3)
247 || strstr(file_header->name, "/../")
249 bb_error_msg_and_die("name with '..' encountered: '%s'",
253 /* Strip trailing '/' in directories */
254 /* Must be done after mode is set as '/' is used to check if it's a directory */
255 cp = last_char_is(file_header->name, '/');
257 if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) {
258 archive_handle->action_header(archive_handle->file_header);
259 /* Note that we kill the '/' only after action_header() */
260 /* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */
262 archive_handle->flags |= ARCHIVE_EXTRACT_QUIET;
263 archive_handle->action_data(archive_handle);
264 llist_add_to(&(archive_handle->passed), file_header->name);
266 data_skip(archive_handle);
267 free(file_header->name);
269 archive_handle->offset += file_header->size;
271 free(file_header->link_name);
272 /* Do not free(file_header->name)! */