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gerrit.nordix.org / codeaurora / busybox / 87ac7028e01cdc4f504ea558a6ae3d086ed1bf2b / . / archival / libunarchive / get_header_zip.c
blob: 84f2a54f2f554e531bf1dbd63087485aec30b3c2 [file] [log] [blame]
Glenn L McGrath87ac7022002-01-02 13:52:26 +0000[diff] [blame^]1/* vi: set sw=4 ts=4: */
2/*
3 * get_header_zip for busybox
4 *
5 * Copyright (C) 2001 by Laurence Anderson
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include "unarchive.h"
26#include "libbb.h"
27
28#define ZIP_FILEHEADER_MAGIC 0x04034b50
29#define ZIP_CDS_MAGIC 0x02014b50
30#define ZIP_CDS_END_MAGIC 0x06054b50
31#define ZIP_DD_MAGIC 0x8074b50
32
33file_header_t *get_header_zip(FILE *zip_stream)
34{
35 struct {
36 short version __attribute__ ((packed));
37 short flags __attribute__ ((packed));
38 short method __attribute__ ((packed));
39 short modtime __attribute__ ((packed));
40 short moddate __attribute__ ((packed));
41 int crc32 __attribute__ ((packed));
42 int cmpsize __attribute__ ((packed));
43 int ucmpsize __attribute__ ((packed));
44 short filename_len __attribute__ ((packed));
45 short extra_len __attribute__ ((packed));
46 } zip_header;
47 file_header_t *zip_entry = NULL;
48 int magic;
49 static int dd_ahead = 0; // If this is true, the we didn't know how long the last extraced file was
50
51 fread (&magic, 4, 1, zip_stream);
52 archive_offset += 4;
53
54 if (feof(zip_stream)) return(NULL);
55checkmagic:
56 switch (magic) {
57 case ZIP_FILEHEADER_MAGIC:
58 zip_entry = xcalloc(1, sizeof(file_header_t));
59 fread (&zip_header, sizeof(zip_header), 1, zip_stream);
60 archive_offset += sizeof(zip_header);
61 if (!(zip_header.method == 8 || zip_header.method == 0)) { printf("Unsupported compression method %d\n", zip_header.method); return(NULL); }
62 zip_entry->name = calloc(zip_header.filename_len + 1, sizeof(char));
63 fread (zip_entry->name, sizeof(char), zip_header.filename_len, zip_stream);
64 archive_offset += zip_header.filename_len;
65 seek_sub_file(zip_stream, zip_header.extra_len);
66 zip_entry->size = zip_header.cmpsize;
67 if (zip_header.method == 8) zip_entry->extract_func = &inflate;
68 zip_entry->mode = S_IFREG | 0777;
69 // Time/Date?
70 if (*(zip_entry->name + strlen(zip_entry->name) - 1) == '/') { // Files that end in a / are directories
71 zip_entry->mode ^= S_IFREG;
72 zip_entry->mode |= S_IFDIR;
73 *(zip_entry->name + strlen(zip_entry->name) - 1) = '\0'; // Remove trailing / so unarchive doesn't get confused
74 }
75 //printf("cmpsize: %d, ucmpsize: %d, method: %d\n", zip_header.cmpsize, zip_header.ucmpsize, zip_header.method);
76 if (zip_header.flags & 0x8) { // crc32, and sizes are in the data description _after_ the file
77 if (zip_header.cmpsize == 0) dd_ahead = 1; // As we don't know how long this file it is difficult to skip! but it is compressed, so normally its ok
78 if (zip_header.ucmpsize != 0) dd_ahead = 2; // Humm... we would otherwise skip this twice - not good!
79 }
80 break;
81 case ZIP_CDS_MAGIC: /* FALLTHRU */
82 case ZIP_CDS_END_MAGIC:
83 return(NULL);
84 break;
85 case ZIP_DD_MAGIC: {
86 int cmpsize;
87 seek_sub_file(zip_stream, 4); // Skip crc32
88 fread(&cmpsize, 4, 1, zip_stream);
89 archive_offset += 4;
90 if (dd_ahead == 1) archive_offset += cmpsize;
91 seek_sub_file(zip_stream, 4); // Skip uncompressed size
92 dd_ahead = 0;
93 return (get_header_zip(zip_stream));
94 break; }
95 default:
96 if (!dd_ahead) error_msg("Invalid magic (%#x): Trying to skip junk", magic);
97 dd_ahead = 0;
98 while (!feof(zip_stream)) {
99 int tmpmagic;
100 tmpmagic = fgetc(zip_stream);
101 archive_offset++;
102 magic = ((magic >> 8) & 0x00ffffff) | ((tmpmagic << 24) & 0xff000000);
103 if (magic == ZIP_FILEHEADER_MAGIC || magic == ZIP_CDS_MAGIC || magic == ZIP_CDS_END_MAGIC) goto checkmagic;
104 }
105 error_msg("End of archive reached: Bad archive");
106 return(NULL);
107 }
108 //if (archive_offset != ftell(zip_stream)) printf("Archive offset out of sync (%d,%d)\n", (int) archive_offset, (int) ftell(zip_stream));
109 return(zip_entry);
110}