diff options
Diffstat (limited to 'sys/pc98/boot/kzipboot/unzip.c')
| -rw-r--r-- | sys/pc98/boot/kzipboot/unzip.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/sys/pc98/boot/kzipboot/unzip.c b/sys/pc98/boot/kzipboot/unzip.c new file mode 100644 index 0000000..93a2c8b --- /dev/null +++ b/sys/pc98/boot/kzipboot/unzip.c @@ -0,0 +1,155 @@ +/* + * unzip.c -- decompress files in gzip or pkzip format. + * Copyright (C) 1992-1993 Jean-loup Gailly + * + * Adapted for Linux booting by Hannu Savolainen 1993 + * Adapted for FreeBSD booting by Serge Vakulenko + * + * This is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License, see the file COPYING. + * + * The code in this file is derived from the file funzip.c written + * and put in the public domain by Mark Adler. + */ + +/* + * This version can extract files in gzip or pkzip format. + * For the latter, only the first entry is extracted, and it has to be + * either deflated or stored. + */ + +#include "gzip.h" + +#include <sys/types.h> +#include <sys/inflate.h> + +/* PKZIP header definitions */ +#define LOCSIG 0x04034b50L /* four-byte lead-in (lsb first) */ +#define LOCFLG 6 /* offset of bit flag */ +#define CRPFLG 1 /* bit for encrypted entry */ +#define EXTFLG 8 /* bit for extended local header */ +#define LOCHOW 8 /* offset of compression method */ +#define LOCTIM 10 /* file mod time (for decryption) */ +#define LOCCRC 14 /* offset of crc */ +#define LOCSIZ 18 /* offset of compressed size */ +#define LOCLEN 22 /* offset of uncompressed length */ +#define LOCFIL 26 /* offset of file name field length */ +#define LOCEXT 28 /* offset of extra field length */ +#define LOCHDR 30 /* size of local header, including sig */ +#define EXTHDR 16 /* size of extended local header, inc sig */ + +int pkzip; /* set for a pkzip file */ +int extended; /* set if extended local header */ + +/* Macros for getting two-byte and four-byte header values */ +#define SH(p) ((ushort)(uchar)((p)[0]) | ((ushort)(uchar)((p)[1]) << 8)) +#define LG(p) ((ulong)(SH(p)) | ((ulong)(SH((p)+2)) << 16)) + +/* + * Check zip file and advance inptr to the start of the compressed data. + * Get ofname from the local header if necessary. + */ +void check_zipfile() +{ + uchar *h = inbuf + inptr; /* first local header */ + + /* Check validity of local header, and skip name and extra fields */ + inptr += LOCHDR + SH(h + LOCFIL) + SH(h + LOCEXT); + + if (inptr > insize || LG(h) != LOCSIG) + error("input not a zip"); + + method = h[LOCHOW]; + if (method != STORED && method != DEFLATED) + error("first entry not deflated or stored--can't extract"); + + /* If entry encrypted, decrypt and validate encryption header */ + if (h[LOCFLG] & CRPFLG) + error("encrypted file"); + + /* Save flags for unzip() */ + extended = (h[LOCFLG] & EXTFLG) != 0; + pkzip = 1; +} + +int +Flush (void *nu, u_char *buf, u_long cnt) +{ + outcnt = cnt; + flush_window(); + return 0; +} + +int +NextByte (void *nu) +{ + return ((int) get_byte ()); +} + +struct inflate infl; /* put it into the BSS */ + +/* + * Unzip in to out. This routine works on both gzip and pkzip files. + * + * IN assertions: the buffer inbuf contains already the beginning of + * the compressed data, from offsets inptr to insize-1 included. + * The magic header has already been checked. The output buffer is cleared. + */ + +void unzip() +{ + ulong orig_crc = 0; /* original crc */ + ulong orig_len = 0; /* original uncompressed length */ + uchar buf[EXTHDR]; /* extended local header */ + int n, res; + + crc = 0xffffffffL; /* initialize crc */ + + if (pkzip && !extended) { /* crc and length at the end otherwise */ + orig_crc = LG(inbuf + LOCCRC); + orig_len = LG(inbuf + LOCLEN); + } + + if (method != DEFLATED) + error("internal error, invalid method"); + infl.gz_input = NextByte; + infl.gz_output = Flush; + infl.gz_slide = window; + res = inflate (&infl); + if (res == 3) + error("out of memory"); + else if (res != 0) + error("invalid compressed format"); + + /* Get the crc and original length */ + if (!pkzip) { + /* crc32 (see algorithm.doc) + * uncompressed input size modulo 2^32 + */ + for (n = 0; n < 8; n++) + buf[n] = get_byte(); /* may cause an error if EOF */ + orig_crc = LG(buf); + orig_len = LG(buf+4); + + } else if (extended) { /* If extended header, check it */ + /* signature - 4bytes: 0x50 0x4b 0x07 0x08 + * CRC-32 value + * compressed size 4-bytes + * uncompressed size 4-bytes + */ + for (n = 0; n < EXTHDR; n++) + buf[n] = get_byte(); /* may cause an error if EOF */ + orig_crc = LG(buf+4); + orig_len = LG(buf+12); + } + + /* Validate decompression */ + if (orig_crc != (crc ^ 0xffffffffL)) + error("crc error"); + if (orig_len != output_ptr) + error("length error"); + + /* Check if there are more entries in a pkzip file */ + if (pkzip && inptr+4 < insize && LG(inbuf+inptr) == LOCSIG) + error("zip file has more than one entry"); +} |
