| /* 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); |
| } |