Contents of /trunk/mkinitrd-magellan/busybox/archival/libunarchive/get_header_tar.c
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Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
File MIME type: text/plain
File size: 8090 byte(s)
Sat Sep 1 22:45:15 2007 UTC (17 years ago) by niro
File MIME type: text/plain
File size: 8090 byte(s)
-import if magellan mkinitrd; it is a fork of redhats mkinitrd-5.0.8 with all magellan patches and features; deprecates magellan-src/mkinitrd
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 |
18 | static char *longname; |
19 | static char *linkname; |
20 | #else |
21 | enum { |
22 | longname = 0, |
23 | linkname = 0, |
24 | }; |
25 | #endif |
26 | |
27 | /* NB: _DESTROYS_ str[len] character! */ |
28 | static 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) |
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 | |
45 | void BUG_tar_header_size(void); |
46 | char get_header_tar(archive_handle_t *archive_handle) |
47 | { |
48 | static int 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 sum, i; |
73 | int parse_names; |
74 | |
75 | if (sizeof(tar) != 512) |
76 | BUG_tar_header_size(); |
77 | |
78 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
79 | again: |
80 | #endif |
81 | /* Align header */ |
82 | data_align(archive_handle, 512); |
83 | |
84 | again_after_align: |
85 | |
86 | xread(archive_handle->src_fd, &tar, 512); |
87 | archive_handle->offset += 512; |
88 | |
89 | /* If there is no filename its an empty header */ |
90 | if (tar.name[0] == 0) { |
91 | if (end) { |
92 | /* This is the second consecutive empty header! End of archive! |
93 | * Read until the end to empty the pipe from gz or bz2 |
94 | */ |
95 | while (full_read(archive_handle->src_fd, &tar, 512) == 512) |
96 | /* repeat */; |
97 | return EXIT_FAILURE; |
98 | } |
99 | end = 1; |
100 | return EXIT_SUCCESS; |
101 | } |
102 | end = 0; |
103 | |
104 | /* Check header has valid magic, "ustar" is for the proper tar |
105 | * 0's are for the old tar format |
106 | */ |
107 | if (strncmp(tar.magic, "ustar", 5) != 0) { |
108 | #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY |
109 | if (memcmp(tar.magic, "\0\0\0\0", 5) != 0) |
110 | #endif |
111 | bb_error_msg_and_die("invalid tar magic"); |
112 | } |
113 | /* Do checksum on headers */ |
114 | sum = ' ' * sizeof(tar.chksum); |
115 | for (i = 0; i < 148 ; i++) { |
116 | sum += ((char*)&tar)[i]; |
117 | } |
118 | for (i = 156; i < 512 ; i++) { |
119 | sum += ((char*)&tar)[i]; |
120 | } |
121 | /* This field does not need special treatment (getOctal) */ |
122 | if (sum != xstrtoul(tar.chksum, 8)) { |
123 | bb_error_msg_and_die("invalid tar header checksum"); |
124 | } |
125 | |
126 | /* 0 is reserved for high perf file, treat as normal file */ |
127 | if (!tar.typeflag) tar.typeflag = '0'; |
128 | parse_names = (tar.typeflag >= '0' && tar.typeflag <= '7'); |
129 | |
130 | /* getOctal trashes subsequent field, therefore we call it |
131 | * on fields in reverse order */ |
132 | if (tar.devmajor[0]) { |
133 | unsigned minor = GET_OCTAL(tar.devminor); |
134 | unsigned major = GET_OCTAL(tar.devmajor); |
135 | file_header->device = makedev(major, minor); |
136 | } |
137 | file_header->link_name = NULL; |
138 | if (!linkname && parse_names && tar.linkname[0]) { |
139 | /* we trash magic[0] here, it's ok */ |
140 | tar.linkname[sizeof(tar.linkname)] = '\0'; |
141 | file_header->link_name = xstrdup(tar.linkname); |
142 | /* FIXME: what if we have non-link object with link_name? */ |
143 | /* Will link_name be free()ed? */ |
144 | } |
145 | file_header->mtime = GET_OCTAL(tar.mtime); |
146 | file_header->size = GET_OCTAL(tar.size); |
147 | file_header->gid = GET_OCTAL(tar.gid); |
148 | file_header->uid = GET_OCTAL(tar.uid); |
149 | /* Set bits 0-11 of the files mode */ |
150 | file_header->mode = 07777 & GET_OCTAL(tar.mode); |
151 | |
152 | file_header->name = NULL; |
153 | if (!longname && parse_names) { |
154 | /* we trash mode[0] here, it's ok */ |
155 | tar.name[sizeof(tar.name)] = '\0'; |
156 | if (tar.prefix[0]) { |
157 | /* and padding[0] */ |
158 | tar.prefix[sizeof(tar.prefix)] = '\0'; |
159 | file_header->name = concat_path_file(tar.prefix, tar.name); |
160 | } else |
161 | file_header->name = xstrdup(tar.name); |
162 | } |
163 | |
164 | /* Set bits 12-15 of the files mode */ |
165 | /* (typeflag was not trashed because chksum does not use getOctal) */ |
166 | switch (tar.typeflag) { |
167 | /* busybox identifies hard links as being regular files with 0 size and a link name */ |
168 | case '1': |
169 | file_header->mode |= S_IFREG; |
170 | break; |
171 | case '7': |
172 | /* case 0: */ |
173 | case '0': |
174 | #if ENABLE_FEATURE_TAR_OLDGNU_COMPATIBILITY |
175 | if (last_char_is(file_header->name, '/')) { |
176 | file_header->mode |= S_IFDIR; |
177 | } else |
178 | #endif |
179 | file_header->mode |= S_IFREG; |
180 | break; |
181 | case '2': |
182 | file_header->mode |= S_IFLNK; |
183 | break; |
184 | case '3': |
185 | file_header->mode |= S_IFCHR; |
186 | break; |
187 | case '4': |
188 | file_header->mode |= S_IFBLK; |
189 | break; |
190 | case '5': |
191 | file_header->mode |= S_IFDIR; |
192 | break; |
193 | case '6': |
194 | file_header->mode |= S_IFIFO; |
195 | break; |
196 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
197 | case 'L': |
198 | /* free: paranoia: tar with several consecutive longnames */ |
199 | free(longname); |
200 | /* For paranoia reasons we allocate extra NUL char */ |
201 | longname = xzalloc(file_header->size + 1); |
202 | /* We read ASCIZ string, including NUL */ |
203 | xread(archive_handle->src_fd, longname, file_header->size); |
204 | archive_handle->offset += file_header->size; |
205 | /* return get_header_tar(archive_handle); */ |
206 | /* gcc 4.1.1 didn't optimize it into jump */ |
207 | /* so we will do it ourself, this also saves stack */ |
208 | goto again; |
209 | case 'K': |
210 | free(linkname); |
211 | linkname = xzalloc(file_header->size + 1); |
212 | xread(archive_handle->src_fd, linkname, file_header->size); |
213 | archive_handle->offset += file_header->size; |
214 | /* return get_header_tar(archive_handle); */ |
215 | goto again; |
216 | case 'D': /* GNU dump dir */ |
217 | case 'M': /* Continuation of multi volume archive */ |
218 | case 'N': /* Old GNU for names > 100 characters */ |
219 | case 'S': /* Sparse file */ |
220 | case 'V': /* Volume header */ |
221 | #endif |
222 | case 'g': /* pax global header */ |
223 | case 'x': { /* pax extended header */ |
224 | off_t sz; |
225 | bb_error_msg("warning: skipping header '%c'", tar.typeflag); |
226 | sz = (file_header->size + 511) & ~(off_t)511; |
227 | archive_handle->offset += sz; |
228 | sz >>= 9; /* sz /= 512 but w/o contortions for signed div */ |
229 | while (sz--) |
230 | xread(archive_handle->src_fd, &tar, 512); |
231 | /* return get_header_tar(archive_handle); */ |
232 | goto again_after_align; |
233 | } |
234 | default: |
235 | bb_error_msg_and_die("unknown typeflag: 0x%x", tar.typeflag); |
236 | } |
237 | |
238 | #if ENABLE_FEATURE_TAR_GNU_EXTENSIONS |
239 | if (longname) { |
240 | file_header->name = longname; |
241 | longname = NULL; |
242 | } |
243 | if (linkname) { |
244 | file_header->link_name = linkname; |
245 | linkname = NULL; |
246 | } |
247 | #endif |
248 | if (!strncmp(file_header->name, "/../"+1, 3) |
249 | || strstr(file_header->name, "/../") |
250 | ) { |
251 | bb_error_msg_and_die("name with '..' encountered: '%s'", |
252 | file_header->name); |
253 | } |
254 | |
255 | /* Strip trailing '/' in directories */ |
256 | /* Must be done after mode is set as '/' is used to check if it's a directory */ |
257 | cp = last_char_is(file_header->name, '/'); |
258 | |
259 | if (archive_handle->filter(archive_handle) == EXIT_SUCCESS) { |
260 | archive_handle->action_header(archive_handle->file_header); |
261 | /* Note that we kill the '/' only after action_header() */ |
262 | /* (like GNU tar 1.15.1: verbose mode outputs "dir/dir/") */ |
263 | if (cp) *cp = '\0'; |
264 | archive_handle->flags |= ARCHIVE_EXTRACT_QUIET; |
265 | archive_handle->action_data(archive_handle); |
266 | llist_add_to(&(archive_handle->passed), file_header->name); |
267 | } else { |
268 | data_skip(archive_handle); |
269 | free(file_header->name); |
270 | } |
271 | archive_handle->offset += file_header->size; |
272 | |
273 | free(file_header->link_name); |
274 | /* Do not free(file_header->name)! */ |
275 | |
276 | return EXIT_SUCCESS; |
277 | } |