mirror of
https://github.com/sheumann/hush.git
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226 lines
7.1 KiB
C
226 lines
7.1 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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* NOTE: This is used by deb_extract to avoid calling the whole tar applet.
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* Its functionality should be merged with tar to avoid duplication
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*/
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "libbb.h"
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/*
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* stdout can be redircted to FILE *output
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* If const char *file_prefix isnt NULL is prepended to all the extracted filenames.
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* The purpose of const char *argument depends on the value of const int untar_function
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*/
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extern char *untar(FILE *src_tar_file, FILE *output, const int untar_function,
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const char *argument, const char *file_prefix)
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{
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typedef struct raw_tar_header {
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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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} raw_tar_header_t;
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raw_tar_header_t raw_tar_header;
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unsigned char *temp = (unsigned char *) &raw_tar_header;
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long i;
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long next_header_offset = 0;
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long uncompressed_count = 0;
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size_t size;
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mode_t mode;
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while (fread((char *) &raw_tar_header, 1, 512, src_tar_file) == 512) {
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long sum = 0;
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if (ferror(src_tar_file) || feof(src_tar_file)) {
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perror_msg("untar: ");
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break;
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}
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uncompressed_count += 512;
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/* Check header has valid magic */
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if (strncmp(raw_tar_header.magic, "ustar", 5) != 0) {
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/*
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* FIXME, Need HELP with this
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*
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* This has to fail silently or it incorrectly reports errors when called from
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* deb_extract.
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* The problem is deb_extract decompresses the .gz file in a child process and
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* untar reads from the child proccess. The child process finishes and exits,
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* but fread reads 0's from the src_tar_file even though the child
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* closed its handle.
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*/
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// error_msg("Invalid tar magic");
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break;
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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 += temp[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 += temp[i];
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}
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if (sum != strtol(raw_tar_header.chksum, NULL, 8)) {
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error_msg("Invalid tar header checksum");
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break;
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}
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/* convert to type'ed variables */
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size = strtol(raw_tar_header.size, NULL, 8);
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parse_mode(raw_tar_header.mode, &mode);
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/* start of next header is at */
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next_header_offset = uncompressed_count + size;
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if (size % 512 != 0) {
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next_header_offset += (512 - size % 512);
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}
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/* If an exclude list is specified check current file against list */
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#if 0
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if (*exclude_list != NULL) {
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i = 0;
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while (exclude_list[i] != 0) {
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if (strncmp(exclude_list[i], raw_tar_header.name, strlen(raw_tar_header.name)) == 0) {
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break;
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}
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i++;
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}
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if (exclude_list[i] != 0) {
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continue;
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}
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}
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#endif
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if (untar_function & (extract_contents | extract_verbose_extract | extract_contents_to_file)) {
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fprintf(output, "%s\n", raw_tar_header.name);
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}
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switch (raw_tar_header.typeflag ) {
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case '0':
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case '\0': {
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/* If the name ends in a '/' then assume it is
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* supposed to be a directory, and fall through
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*/
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int name_length = strlen(raw_tar_header.name);
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if (raw_tar_header.name[name_length - 1] != '/') {
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switch (untar_function) {
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case (extract_extract):
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case (extract_verbose_extract):
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case (extract_control): {
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FILE *dst_file = NULL;
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char *full_name;
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if (file_prefix != NULL) {
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full_name = xmalloc(strlen(argument) + strlen(file_prefix) + name_length + 3);
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sprintf(full_name, "%s/%s.%s", argument, file_prefix, strrchr(raw_tar_header.name, '/') + 1);
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} else {
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full_name = concat_path_file(argument, raw_tar_header.name);
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}
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dst_file = wfopen(full_name, "w");
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copy_file_chunk(src_tar_file, dst_file, (unsigned long long) size);
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uncompressed_count += size;
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fclose(dst_file);
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chmod(full_name, mode);
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free(full_name);
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}
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break;
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case (extract_info):
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if (strstr(raw_tar_header.name, argument) != NULL) {
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copy_file_chunk(src_tar_file, stdout, (unsigned long long) size);
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uncompressed_count += size;
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}
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break;
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case (extract_field):
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if (strstr(raw_tar_header.name, "./control") != NULL) {
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return(read_text_file_to_buffer(src_tar_file));
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}
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break;
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}
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break;
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}
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}
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case '5':
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if (untar_function & (extract_extract | extract_verbose_extract | extract_control)) {
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int ret;
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char *dir;
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dir = concat_path_file(argument, raw_tar_header.name);
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ret = create_path(dir, mode);
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free(dir);
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if (ret == FALSE) {
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perror_msg("%s: Cannot mkdir", raw_tar_header.name);
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return NULL;
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}
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chmod(dir, mode);
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}
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break;
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case '1':
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if (untar_function & (extract_extract | extract_verbose_extract | extract_control)) {
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if (link(raw_tar_header.linkname, raw_tar_header.name) < 0) {
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perror_msg("%s: Cannot create hard link to '%s'", raw_tar_header.name, raw_tar_header.linkname);
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return NULL;
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}
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}
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break;
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case '2':
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if (untar_function & (extract_extract | extract_verbose_extract | extract_control)) {
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if (symlink(raw_tar_header.linkname, raw_tar_header.name) < 0) {
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perror_msg("%s: Cannot create symlink to '%s'", raw_tar_header.name, raw_tar_header.linkname);
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return NULL;
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}
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}
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break;
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case '3':
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case '4':
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case '6':
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// if (tarExtractSpecial( &header, extractFlag, tostdoutFlag)==FALSE)
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// errorFlag=TRUE;
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// break;
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default:
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error_msg("Unknown file type '%c' in tar file", raw_tar_header.typeflag);
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return NULL;
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}
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/*
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* Seek to start of next block, cant use fseek as unzip() does support it
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*/
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while (uncompressed_count < next_header_offset) {
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if (fgetc(src_tar_file) == EOF) {
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break;
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}
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uncompressed_count++;
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}
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}
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return NULL;
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}
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