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/* vi: set sw=4 ts=4: */
/*
* get_header_zip for busybox
*
* Copyright (C) 2001 by Laurence Anderson
*
* 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
* 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 <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "unarchive.h"
#include "libbb.h"
#define ZIP_FILEHEADER_MAGIC 0x04034b50
#define ZIP_CDS_MAGIC 0x02014b50
#define ZIP_CDS_END_MAGIC 0x06054b50
#define ZIP_DD_MAGIC 0x08074b50
enum {
zh_version,
zh_flags,
zh_method,
zh_modtime,
zh_moddate,
zh_crc32,
zh_cmpsize,
zh_ucmpsize,
zh_filename_len,
zh_extra_len
};
static const char fail_msg[] = "Invalid file or read error";
static int le_read_int(FILE *fp, int n)
{
int r = 0;
int s = 1;
int c;
archive_offset += n;
do {
if ((c = fgetc(fp)) == EOF) {
error_msg_and_die(fail_msg);
}
r += s * c;
s <<= 8;
} while (--n);
return r;
}
static void read_header(FILE *fp, int *zh)
{
static const char s[] = { 2, 2, 2, 2, 2, 4, 4, 4, 2, 2, 0 };
int i = 0;
do {
zh[i] = le_read_int(fp, s[i]);
} while (s[++i]);
}
file_header_t *get_header_zip(FILE *zip_stream)
{
int zip_header[10];
file_header_t *zip_entry = NULL;
int magic, tmpmagic;
/* If dd_ahead is true, we didn't know the last extracted file's length. */
static int dd_ahead = 0;
magic = le_read_int(zip_stream, 4);
checkmagic:
switch (magic) {
case ZIP_FILEHEADER_MAGIC:
zip_entry = xcalloc(1, sizeof(file_header_t));
read_header(zip_stream, zip_header);
if (zip_header[zh_method] == 8) {
zip_entry->extract_func = &inflate;
} else if (zip_header[zh_method] != 0) {
error_msg_and_die("Unsupported compression method %d\n",
zip_header[zh_method]);
}
zip_entry->name = xmalloc(zip_header[zh_filename_len] + 1);
if (!fread(zip_entry->name, zip_header[zh_filename_len], 1, zip_stream)) {
error_msg_and_die(fail_msg);
}
archive_offset += zip_header[zh_filename_len];
seek_sub_file(zip_stream, zip_header[zh_extra_len]);
zip_entry->size = zip_header[zh_cmpsize];
zip_entry->mode = S_IFREG | 0777;
/* Time/Date? */
zip_entry->name[zip_header[zh_filename_len]] = 0;
if (*(zip_entry->name + zip_header[zh_filename_len] - 1) == '/') {
/* Files that end in a / are directories */
/* Remove trailing / so unarchive doesn't get confused */
*(zip_entry->name + zip_header[zh_filename_len] - 1) = '\0';
zip_entry->mode ^= S_IFREG;
zip_entry->mode |= S_IFDIR;
}
if (zip_header[zh_flags] & 0x8) {
/* crc32, and sizes are in the data description _after_ the file */
if (zip_header[zh_cmpsize] == 0) {
/* As we don't know how long this file it is difficult to skip!
* but it is compressed, so normally its ok */
dd_ahead = 1;
}
if (zip_header[zh_ucmpsize] != 0) {
/* Humm... we would otherwise skip this twice - not good! */
dd_ahead = 2;
}
}
break;
case ZIP_CDS_MAGIC: /* FALLTHRU */
case ZIP_CDS_END_MAGIC:
return(NULL);
break;
case ZIP_DD_MAGIC: {
int cmpsize;
seek_sub_file(zip_stream, 4); // Skip crc32
cmpsize = le_read_int(zip_stream, 4);
if (dd_ahead == 1) archive_offset += cmpsize;
seek_sub_file(zip_stream, 4); // Skip uncompressed size
dd_ahead = 0;
return (get_header_zip(zip_stream));
break; }
default:
if (!dd_ahead) error_msg("Invalid magic (%#x): Trying to skip junk", magic);
dd_ahead = 0;
while ((tmpmagic = fgetc(zip_stream)) != EOF) {
archive_offset++;
magic = ((magic >> 8) & 0x00ffffff) | ((tmpmagic << 24) & 0xff000000);
if (magic == ZIP_FILEHEADER_MAGIC
|| magic == ZIP_CDS_MAGIC
|| magic == ZIP_CDS_END_MAGIC) {
goto checkmagic;
}
}
error_msg_and_die(fail_msg);
}
return(zip_entry);
}
|
