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