111 lines
4.3 KiB
C
111 lines
4.3 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* get_header_zip for busybox
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*
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* Copyright (C) 2001 by Laurence Anderson
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*
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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 GNU
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* 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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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "unarchive.h"
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#include "libbb.h"
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#define ZIP_FILEHEADER_MAGIC 0x04034b50
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#define ZIP_CDS_MAGIC 0x02014b50
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#define ZIP_CDS_END_MAGIC 0x06054b50
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#define ZIP_DD_MAGIC 0x8074b50
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file_header_t *get_header_zip(FILE *zip_stream)
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{
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struct {
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short version __attribute__ ((packed));
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short flags __attribute__ ((packed));
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short method __attribute__ ((packed));
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short modtime __attribute__ ((packed));
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short moddate __attribute__ ((packed));
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int crc32 __attribute__ ((packed));
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int cmpsize __attribute__ ((packed));
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int ucmpsize __attribute__ ((packed));
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short filename_len __attribute__ ((packed));
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short extra_len __attribute__ ((packed));
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} zip_header;
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file_header_t *zip_entry = NULL;
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int magic;
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static int dd_ahead = 0; // If this is true, the we didn't know how long the last extraced file was
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fread (&magic, 4, 1, zip_stream);
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archive_offset += 4;
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if (feof(zip_stream)) return(NULL);
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checkmagic:
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switch (magic) {
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case ZIP_FILEHEADER_MAGIC:
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zip_entry = xcalloc(1, sizeof(file_header_t));
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fread (&zip_header, sizeof(zip_header), 1, zip_stream);
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archive_offset += sizeof(zip_header);
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if (!(zip_header.method == 8 || zip_header.method == 0)) { printf("Unsupported compression method %d\n", zip_header.method); return(NULL); }
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zip_entry->name = calloc(zip_header.filename_len + 1, sizeof(char));
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fread (zip_entry->name, sizeof(char), zip_header.filename_len, zip_stream);
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archive_offset += zip_header.filename_len;
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seek_sub_file(zip_stream, zip_header.extra_len);
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zip_entry->size = zip_header.cmpsize;
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if (zip_header.method == 8) zip_entry->extract_func = &inflate;
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zip_entry->mode = S_IFREG | 0777;
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// Time/Date?
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if (*(zip_entry->name + strlen(zip_entry->name) - 1) == '/') { // Files that end in a / are directories
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zip_entry->mode ^= S_IFREG;
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zip_entry->mode |= S_IFDIR;
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*(zip_entry->name + strlen(zip_entry->name) - 1) = '\0'; // Remove trailing / so unarchive doesn't get confused
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}
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//printf("cmpsize: %d, ucmpsize: %d, method: %d\n", zip_header.cmpsize, zip_header.ucmpsize, zip_header.method);
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if (zip_header.flags & 0x8) { // crc32, and sizes are in the data description _after_ the file
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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
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if (zip_header.ucmpsize != 0) dd_ahead = 2; // Humm... we would otherwise skip this twice - not good!
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}
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break;
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case ZIP_CDS_MAGIC: /* FALLTHRU */
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case ZIP_CDS_END_MAGIC:
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return(NULL);
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break;
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case ZIP_DD_MAGIC: {
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int cmpsize;
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seek_sub_file(zip_stream, 4); // Skip crc32
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fread(&cmpsize, 4, 1, zip_stream);
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archive_offset += 4;
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if (dd_ahead == 1) archive_offset += cmpsize;
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seek_sub_file(zip_stream, 4); // Skip uncompressed size
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dd_ahead = 0;
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return (get_header_zip(zip_stream));
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break; }
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default:
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if (!dd_ahead) error_msg("Invalid magic (%#x): Trying to skip junk", magic);
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dd_ahead = 0;
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while (!feof(zip_stream)) {
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int tmpmagic;
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tmpmagic = fgetc(zip_stream);
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archive_offset++;
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magic = ((magic >> 8) & 0x00ffffff) | ((tmpmagic << 24) & 0xff000000);
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if (magic == ZIP_FILEHEADER_MAGIC || magic == ZIP_CDS_MAGIC || magic == ZIP_CDS_END_MAGIC) goto checkmagic;
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}
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error_msg("End of archive reached: Bad archive");
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return(NULL);
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}
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//if (archive_offset != ftell(zip_stream)) printf("Archive offset out of sync (%d,%d)\n", (int) archive_offset, (int) ftell(zip_stream));
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return(zip_entry);
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}
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