99 lines
3.0 KiB
C
99 lines
3.0 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "unarchive.h"
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#include "libbb.h"
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file_header_t *get_header_tar(FILE *tar_stream)
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{
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union {
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unsigned char raw[512];
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struct {
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char name[100]; /* 0-99 */
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char mode[8]; /* 100-107 */
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char uid[8]; /* 108-115 */
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char gid[8]; /* 116-123 */
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char size[12]; /* 124-135 */
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char mtime[12]; /* 136-147 */
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char chksum[8]; /* 148-155 */
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char typeflag; /* 156-156 */
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char linkname[100]; /* 157-256 */
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char magic[6]; /* 257-262 */
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char version[2]; /* 263-264 */
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char uname[32]; /* 265-296 */
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char gname[32]; /* 297-328 */
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char devmajor[8]; /* 329-336 */
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char devminor[8]; /* 337-344 */
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char prefix[155]; /* 345-499 */
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char padding[12]; /* 500-512 */
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} formated;
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} tar;
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file_header_t *tar_entry = NULL;
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long sum = 0;
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long i;
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if (archive_offset % 512 != 0) {
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seek_sub_file(tar_stream, 512 - (archive_offset % 512));
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}
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if (fread(tar.raw, 1, 512, tar_stream) != 512) {
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/* Unfortunatly its common for tar files to have all sorts of
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* trailing garbage, fail silently */
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// error_msg("Couldnt read header");
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return(NULL);
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}
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archive_offset += 512;
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/* Check header has valid magic, unfortunately some tar files
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* have empty (0'ed) tar entries at the end, which will
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* cause this to fail, so fail silently for now
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*/
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if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
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return(NULL);
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}
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/* Do checksum on headers */
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for (i = 0; i < 148 ; i++) {
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sum += tar.raw[i];
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}
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sum += ' ' * 8;
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for (i = 156; i < 512 ; i++) {
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sum += tar.raw[i];
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}
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if (sum != strtol(tar.formated.chksum, NULL, 8)) {
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error_msg("Invalid tar header checksum");
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return(NULL);
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}
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/* convert to type'ed variables */
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tar_entry = xcalloc(1, sizeof(file_header_t));
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tar_entry->name = xstrdup(tar.formated.name);
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parse_mode(tar.formated.mode, &tar_entry->mode);
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tar_entry->uid = strtol(tar.formated.uid, NULL, 8);
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tar_entry->gid = strtol(tar.formated.gid, NULL, 8);
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tar_entry->size = strtol(tar.formated.size, NULL, 8);
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tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
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tar_entry->link_name = strlen(tar.formated.linkname) ?
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xstrdup(tar.formated.linkname) : NULL;
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tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
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strtol(tar.formated.devminor, NULL, 8);
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return(tar_entry);
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} |