The magic code to uncompress a kernel.

Reviewed by:	phk
Obtained from:	Linux via 386BSD.

8 files changed, 923 insertions, 0 deletions

diff --git a/sys/i386/boot/kzipboot/Makefile b/sys/i386/boot/kzipboot/Makefile
new file mode 100644
index 0000000..3ed6f52
--- /dev/null
+++ b/sys/i386/boot/kzipboot/Makefile
@@ -0,0 +1,23 @@
+# $Id$
+
+PROG= kzip.o
+SRCS= head.S boot.c unzip.c misc.c malloc.c inflate.c
+BINDIR= /usr/lib
+.PATH:	${.CURDIR}/../../../kern
+NOMAN= toobad
+
+# Where to load the kernel
+KADDR   = 0x100000
+
+# What segment our code lives in
+CSEG    = 0x8
+
+STRIP=	#  very important!! don't let kzip.o be stripped
+
+CFLAGS+= -DKADDR=$(KADDR) -DCSEG=$(CSEG)
+CFLAGS+= -DUSE_KERNEL_INFLATE -DKZIP -DCOMCONSOLE=0x3F8
+
+kzip.o:  ${OBJS}
+	$(LD) -r -x -o kzip.o $(OBJS)
+
+.include <bsd.prog.mk>
diff --git a/sys/i386/boot/kzipboot/README b/sys/i386/boot/kzipboot/README
new file mode 100644
index 0000000..2845cbe
--- /dev/null
+++ b/sys/i386/boot/kzipboot/README
@@ -0,0 +1,49 @@
+/* Beware: mostly obsolete info */
+
+This is the first (alpha) release of kernel packer/unpacker
+for FreeBSD.  It is based on xBoot from Linux, but
+hardly rewritten.
+
+It assumes that:
+1) The kernel should be loaded at 0x100000 phys address.
+2) The CS selector is equal to 8, which is OK for all
+   current secondary boot programs.
+
+Run "make install" to install it.  It will place
+"kzip" shell script into /usr/sbin, and several files
+into /usr/libexec/kzip directory.
+
+Then try to zip your kernel, for example:
+
+	% kzip /kernel
+	System size is 462848
+	Compressed size 247027
+
+It will create file /kernel.kz:
+
+	% ls -l /kernel /kernel.kz
+	-rwxr-xr-x    1 root       497297 Oct  8 12:41 /386bsd
+	-rwxrwxr-x    1 root       262144 Oct  8 13:37 /386bsd.kz
+
+Then rename /kernel.kz to /kernel and reboot.
+
+	% mv /kernel /o3kernel
+	% mv /kernel.kz /kernel
+	% sync
+	% reboot
+
+During booting, you will see the message:
+
+	Uncompressing kernel...done
+	Booting the kernel
+
+The packed kernel should load and run.
+
+The main problem with packed kernel is the lack of symbol table,
+so all commands that require it, will not run.
+Among them: ps, savecore, *stat, etc.
+
+Packed kernels are good for install and fixit floppies.
+
+Serge Vakulenko, <vak@zebub.msk.su>
+Opdated for FreeBSD 2.1 by Gary Jennejohn 12FEB95
diff --git a/sys/i386/boot/kzipboot/boot.c b/sys/i386/boot/kzipboot/boot.c
new file mode 100644
index 0000000..16ccefd
--- /dev/null
+++ b/sys/i386/boot/kzipboot/boot.c
@@ -0,0 +1,142 @@
+/* 
+ * FreeBSD kernel unpacker.
+ * 1993 by Serge Vakulenko
+ * modified for FreeBSD 2.1 by Gary Jennejohn - 12FEB95
+ */
+
+#include <machine/cpufunc.h> /* for inb/outb */
+#include <sys/reboot.h> /* for RB_SERIAL */
+
+short *videomem;
+int curs;
+int cols;
+int lines;
+unsigned int port;
+
+unsigned char bios[0x100];
+
+extern int end, edata;
+
+void decompress_kernel (void *dest);
+
+#if 0
+inline void outb (unsigned short x, unsigned char y)
+{
+	asm volatile ("outb %0, %1" : : "a" (y) , "d" (x));
+}
+
+inline unsigned char inb (unsigned short x, unsigned char y)
+{
+	asm volatile ("inb %0, %1" : : "a" (y) , "d" (x));
+}
+#endif
+
+int memcmp (const void *arg1, const void *arg2, unsigned len)
+{
+	unsigned char *a = (unsigned char*) arg1;
+	unsigned char *b = (unsigned char*) arg2;
+
+	for (; len-- > 0; ++a, ++b)
+		if (*a < *b)
+			return (-1);
+		else if (*a > *b)
+			return (1);
+	return (0);
+}
+
+void *memcpy (void *to, const void *from, unsigned len)
+{
+	char *f = (char*) from;
+	char *t = (char*) to;
+
+	while (len-- > 0)
+		*t++ = *f++;
+	return (to);
+}
+
+void serial_putchar (unsigned char c)
+{
+	unsigned char stat;
+
+	do {
+		 stat = inb (COMCONSOLE+5);
+	} while (stat & 0x20);
+
+	outb (COMCONSOLE, c);
+}
+
+void putchar (unsigned char c)
+{
+	switch (c) {
+	case '\n':      curs = (curs + cols) / cols * cols;     break;
+	default:        videomem[curs++] = 0x0700 | c;          break;
+	}
+	while (curs >= cols*lines) {
+		memcpy (videomem, videomem+cols, (lines-1) * cols * 2);
+		curs -= cols;
+	}
+	/* set cursor position */
+	outb (port, 0x0e); outb (port+1, curs>>8);
+	outb (port, 0x0f); outb (port+1, curs);
+}
+
+int use_serial;
+
+void putstr (char *s)
+{
+	while (*s) {
+		if (use_serial)
+			serial_putchar (*s++);
+		else
+			putchar (*s++);
+	}
+}
+
+void error (char *s)
+{
+	putstr ("\n\n");
+	putstr (s);
+	putstr ("\n\n -- System halted");
+	while (1);                      /* Halt */
+}
+
+void boot (int howto)
+{
+	int l, c, *p;
+
+	/* clear bss */
+	for (p = &edata; p < &end; ++p)
+		*p = 0;
+
+	if (!(use_serial = (howto & RB_SERIAL))) {
+		/* Test for monochrome video adapter */
+		if ((*((unsigned char*) 0x410) & 0x30) == 0x30)
+			videomem = (void*) 0xb0000;     /* monochrome */
+		else
+			videomem = (void*) 0xb8000;     /* color */
+
+		port = *(unsigned short*) 0x463;
+		cols = *(unsigned short*) 0x44a;
+		lines = 1 + *(unsigned char*) 0x484;
+		c = *(unsigned char*) 0x450;
+		l = *(unsigned char*) 0x451;
+
+		if (lines < 25)
+			lines = 25;
+		curs = l*cols + c;
+		if (curs > lines*cols)
+			curs = (lines-1) * cols;
+	}
+
+	/* save bios area */
+	memcpy (bios, (void*) 0x400, sizeof (bios));
+
+	putstr ("Uncompressing kernel...");
+	decompress_kernel ((void*) KADDR);
+	putstr ("done\n");
+
+	/* restore bios area */
+	memcpy ((void*) 0x400, bios, sizeof (bios));
+
+	putstr ("Booting the kernel\n");
+}
diff --git a/sys/i386/boot/kzipboot/gzip.h b/sys/i386/boot/kzipboot/gzip.h
new file mode 100644
index 0000000..0ad5ce35
--- /dev/null
+++ b/sys/i386/boot/kzipboot/gzip.h
@@ -0,0 +1,84 @@
+/*
+ * gzip.h -- common declarations for all gzip modules
+ * Copyright (C) 1992-1993 Jean-loup Gailly.
+ * Adapted for FreeBSD boot unpacker 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.
+ */
+
+typedef unsigned char  uchar;
+#ifndef USE_KERNEL_INFLATE
+typedef unsigned short ushort;
+#endif
+typedef unsigned long  ulong;
+
+#define NULL 0
+
+#define STORED          0               /* Compression methods */
+#define COMPRESSED      1
+#define PACKED          2
+#define DEFLATED        8               /* methods 3 to 7 reserved */
+
+#define INBUFSIZ        0x8000          /* input buffer size */
+
+#define OUTBUFSIZ       16384           /* output buffer size */
+#define OUTBUF_EXTRA    2048            /* required by unlzw() */
+
+#define GZIP_MAGIC      "\037\213"      /* gzip files, 1F 8B */
+#define OLD_GZIP_MAGIC  "\037\236"      /* gzip 0.5 = freeze 1.x */
+#define PKZIP_MAGIC     "PK\003\004"    /* pkzip files */
+#define PACK_MAGIC      "\037\036"      /* packed files */
+#define LZW_MAGIC       "\037\235"      /* lzw files, 1F 9D */
+
+/* gzip flag byte */
+#define ASCII_FLAG      0x01            /* file probably ascii text */
+#define CONTINUATION    0x02            /* cont. of multi-part gzip file */
+#define EXTRA_FIELD     0x04            /* extra field present */
+#define ORIG_NAME       0x08            /* original file name present */
+#define COMMENT         0x10            /* file comment present */
+#define ENCRYPTED       0x20            /* file is encrypted */
+#define RESERVED        0xC0            /* reserved */
+
+/* window size--must be a power of two, and */
+/* at least 32K for zip's deflate method */
+#define WSIZE           0x8000
+
+extern int method;      /* compression method */
+
+extern uchar inbuf[];   /* input buffer */
+extern uchar outbuf[];  /* output buffer */
+extern uchar window[];  /* Sliding window and suffix table (unlzw) */
+
+extern unsigned insize; /* valid bytes in inbuf */
+extern unsigned inptr;  /* index of next byte to be processed in inbuf */
+extern unsigned outcnt; /* bytes in output buffer */
+
+extern int pkzip;               /* set for a pkzip file */
+extern int extended;            /* set if extended local header */
+extern ulong crc;               /* shift register contents */
+extern ulong output_ptr;        /* total output bytes */
+
+extern void unzip (void);
+extern void check_zipfile (void);
+extern void updcrc (uchar *s, unsigned n);
+extern void clear_bufs (void);
+extern void fill_inbuf (void);
+extern void flush_window (void);
+extern void error (char *m);
+#ifndef USE_KERNEL_INFLATE
+extern int inflate (void);
+#endif
+
+static inline uchar get_byte ()
+{
+	if (inptr >= insize)
+		fill_inbuf ();
+	return (inbuf[inptr++]);
+}
+
+static inline void put_char (uchar c)
+{
+	window[outcnt++] = c;
+	if (outcnt == WSIZE)
+		flush_window();
+}
diff --git a/sys/i386/boot/kzipboot/head.S b/sys/i386/boot/kzipboot/head.S
new file mode 100644
index 0000000..a3e8e6d
--- /dev/null
+++ b/sys/i386/boot/kzipboot/head.S
@@ -0,0 +1,10 @@
+/*
+ * Boot unpacker startup routine.
+ * Copyright (C) Serge Vakulenko
+ */
+	.text
+start:
+	cli                             # disable interrupts
+	call    _boot                   # unpack the kernel image
+	ljmp    $CSEG, $KADDR           # jump to unpacked kernel
+	. = start + 0x500               # skip over warm boot shit
diff --git a/sys/i386/boot/kzipboot/malloc.c b/sys/i386/boot/kzipboot/malloc.c
new file mode 100644
index 0000000..ef57458
--- /dev/null
+++ b/sys/i386/boot/kzipboot/malloc.c
@@ -0,0 +1,229 @@
+/*
+ * Copyright (c) 1983, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * malloc.c (Caltech) 2/21/82
+ * Chris Kingsley, kingsley@cit-20.
+ *
+ * This is a very fast storage allocator.  It allocates blocks of a small 
+ * number of different sizes, and keeps free lists of each size.  Blocks that
+ * don't exactly fit are passed up to the next larger size.  In this 
+ * implementation, the available sizes are 2^n-4 (or 2^n-10) bytes long.
+ * This is designed for use in a virtual memory environment.
+ *
+ * Modified for stand-alone use (for kzip) by Gary Jennejohn - 12FEB95
+ */
+#ifdef USE_KERNEL_INFLATE
+
+#include <sys/types.h>
+
+#define	NULL 0
+
+/*
+ * The overhead on a block is at least 4 bytes.  When free, this space
+ * contains a pointer to the next free block, and the bottom two bits must
+ * be zero.  When in use, the first byte is set to MAGIC, and the second
+ * byte is the size index.  The remaining bytes are for alignment.
+ * If range checking is enabled then a second word holds the size of the
+ * requested block, less 1, rounded up to a multiple of sizeof(RMAGIC).
+ * The order of elements is critical: ov_magic must overlay the low order
+ * bits of ov_next, and ov_magic can not be a valid ov_next bit pattern.
+ */
+union	overhead {
+	union	overhead *ov_next;	/* when free */
+	struct {
+		u_char	ovu_magic;	/* magic number */
+		u_char	ovu_index;	/* bucket # */
+	} ovu;
+#define	ov_magic	ovu.ovu_magic
+#define	ov_index	ovu.ovu_index
+#define	ov_rmagic	ovu.ovu_rmagic
+#define	ov_size		ovu.ovu_size
+};
+
+#define	MAGIC		0xef		/* magic # on accounting info */
+#define RMAGIC		0x5555		/* magic # on range info */
+
+#define	RSLOP		0
+
+/*
+ * nextf[i] is the pointer to the next free block of size 2^(i+3).  The
+ * smallest allocatable block is 8 bytes.  The overhead information
+ * precedes the data area returned to the user.
+ */
+#define	NBUCKETS 30
+static	union overhead *nextf[NBUCKETS];
+
+static	int pagesz;			/* page size */
+static	int pagebucket;			/* page size bucket */
+
+#define STORAGE 40960 /* must be at least this big to handle GENERIC */
+unsigned char storage [STORAGE];
+int next_free; /* need this to emulate sbrk() */
+
+#define	ASSERT(p)
+
+static void morecore (int);
+
+void *
+malloc(nbytes, junk1, junk2) /* junk? not used */
+	size_t nbytes;
+	int junk1, junk2;
+{
+  	register union overhead *op;
+  	register int bucket, n;
+	register unsigned amt;
+
+	/*
+	 * First time malloc is called, setup page size and
+	 * align break pointer so all data will be page aligned.
+	 */
+	if (pagesz == 0) {
+		pagesz = n = 4096;
+		op = (union overhead *)storage;
+  		n = n - sizeof (*op) - ((int)op & (n - 1));
+		if (n < 0)
+			n += pagesz;
+  		if (n > STORAGE)
+				return (NULL);
+
+		next_free = n;
+
+		bucket = 0;
+		amt = 8;
+		while (pagesz > amt) {
+			amt <<= 1;
+			bucket++;
+		}
+		pagebucket = bucket;
+	}
+	/*
+	 * Convert amount of memory requested into closest block size
+	 * stored in hash buckets which satisfies request.
+	 * Account for space used per block for accounting.
+	 */
+	if (nbytes <= (n = pagesz - sizeof (*op) - RSLOP)) {
+		amt = 8;	/* size of first bucket */
+		bucket = 0;
+		n = -(sizeof (*op) + RSLOP);
+	} else {
+		amt = pagesz;
+		bucket = pagebucket;
+	}
+	while (nbytes > amt + n) {
+		amt <<= 1;
+		if (amt == 0)
+			return (NULL);
+		bucket++;
+	}
+	/*
+	 * If nothing in hash bucket right now,
+	 * request more memory from the system.
+	 */
+ 	if ((op = nextf[bucket]) == NULL) {
+  		morecore(bucket);
+  		if ((op = nextf[bucket]) == NULL)
+  			return (NULL);
+	}
+
+	/* remove from linked list */
+  	nextf[bucket] = op->ov_next;
+	op->ov_magic = MAGIC;
+	op->ov_index = bucket;
+  	return ((char *)(op + 1));
+}
+
+/*
+ * Allocate more memory to the indicated bucket.
+ */
+static void
+morecore(bucket)
+	int bucket;
+{
+  	register union overhead *op;
+	register int sz;		/* size of desired block */
+  	int amt;			/* amount to allocate */
+  	int nblks;			/* how many blocks we get */
+
+	/*
+	 * sbrk_size <= 0 only for big, FLUFFY, requests (about
+	 * 2^30 bytes on a VAX, I think) or for a negative arg.
+	 */
+	sz = 1 << (bucket + 3);
+
+	if (sz <= 0)
+		return;
+
+	if (sz < pagesz) {
+		amt = pagesz;
+  		nblks = amt / sz;
+	} else {
+		amt = sz + pagesz;
+		nblks = 1;
+	}
+	/* no more room! */
+	if (amt > (STORAGE - next_free))
+		return;
+	op = (union overhead *)&storage [next_free];
+	next_free += amt;
+	/*
+	 * Add new memory allocated to that on
+	 * free list for this hash bucket.
+	 */
+  	nextf[bucket] = op;
+  	while (--nblks > 0) {
+		op->ov_next = (union overhead *)((caddr_t)op + sz);
+		op = (union overhead *)((caddr_t)op + sz);
+  	}
+}
+
+void
+free(cp, junk) /* junk not used */
+	void *cp;
+	int junk;
+{   
+  	register int size;
+	register union overhead *op;
+
+  	if (cp == NULL)
+  		return;
+	op = (union overhead *)((caddr_t)cp - sizeof (union overhead));
+	if (op->ov_magic != MAGIC)
+		return;				/* sanity */
+  	size = op->ov_index;
+  	ASSERT(size < NBUCKETS);
+	op->ov_next = nextf[size];	/* also clobbers ov_magic */
+  	nextf[size] = op;
+}
+
+#endif /* USE_KERNEL_INFLATE */
diff --git a/sys/i386/boot/kzipboot/misc.c b/sys/i386/boot/kzipboot/misc.c
new file mode 100644
index 0000000..13396f4
--- /dev/null
+++ b/sys/i386/boot/kzipboot/misc.c
@@ -0,0 +1,211 @@
+/*
+ * misc.c
+ * 
+ * This is a collection of several routines from gzip-1.0.3 
+ * adapted for Linux.
+ *
+ * Ported to 386bsd by Serge Vakulenko
+ */
+
+#include "gzip.h"
+
+uchar inbuf [INBUFSIZ];
+uchar outbuf [OUTBUFSIZ+OUTBUF_EXTRA];
+uchar window [WSIZE];
+
+unsigned outcnt;
+unsigned insize;
+unsigned inptr;
+
+extern const char input_data[];
+extern const int input_len;
+
+int input_ptr;
+
+int method;
+
+char *output_data;
+ulong output_ptr;
+
+void makecrc (void);
+void putstr (char *c);
+void *memcpy (void *to, const void *from, unsigned len);
+int memcmp (const void *arg1, const void *arg2, unsigned len);
+
+ulong crc;                              /* shift register contents */
+ulong crc_32_tab[256];                  /* crc table, defined below */
+
+/*
+ * Run a set of bytes through the crc shift register.  If s is a NULL
+ * pointer, then initialize the crc shift register contents instead.
+ * Return the current crc in either case.
+ */
+void updcrc(s, n)
+uchar *s;                       /* pointer to bytes to pump through */
+unsigned n;                     /* number of bytes in s[] */
+{
+	while (n--)
+		crc = crc_32_tab[(uchar)crc ^ (*s++)] ^ (crc >> 8);
+}
+
+/*
+ * Clear input and output buffers
+ */
+void clear_bufs()
+{
+	outcnt = 0;
+	insize = inptr = 0;
+}
+
+/*
+ * Fill the input buffer. This is called only when the buffer is empty
+ * and at least one byte is really needed.
+ */
+void fill_inbuf ()
+{
+	int len, i;
+
+	/* Read as much as possible */
+	insize = 0;
+	do {
+		len = INBUFSIZ - insize;
+		if (len > input_len - input_ptr + 1)
+			len = input_len-input_ptr+1;
+		if (len <= 0)
+			break;
+		for (i=0; i<len; i++)
+			inbuf[insize+i] = input_data[input_ptr+i];
+		insize += len;
+		input_ptr += len;
+	} while (insize < INBUFSIZ);
+	if (insize == 0)
+		error("unable to fill buffer");
+	inptr = 0;
+}
+
+/*
+ * Write the output window window[0..outcnt-1] and update crc and bytes_out.
+ * (Used for the decompressed data only.)
+ */
+void flush_window()
+{
+	if (outcnt == 0) return;
+	updcrc(window, outcnt);
+
+	memcpy(&output_data[output_ptr], (char *)window, outcnt);
+
+	output_ptr += outcnt;
+	outcnt = 0;
+}
+
+/*
+ * Code to compute the CRC-32 table. Borrowed from 
+ * gzip-1.0.3/makecrc.c.
+ * Not copyrighted 1990 Mark Adler
+ */
+void makecrc(void)
+{
+	ulong c;        /* crc shift register */
+	ulong e;        /* polynomial exclusive-or pattern */
+	int i;          /* counter for all possible eight bit values */
+	int k;          /* byte being shifted into crc apparatus */
+
+	/* terms of polynomial defining this crc (except x^32): */
+	static const uchar poly[] = { 0,1,2,4,5,7,8,10,11,12,16,22,23,26, };
+
+	/* Make exclusive-or pattern from polynomial */
+	e = 0;
+	for (i = 0; i < sizeof(poly)/sizeof(*poly); i++)
+		e |= 1L << (31 - poly[i]);
+
+	crc_32_tab[0] = 0;
+
+	for (i = 1; i < 256; i++) {
+		c = 0;
+		for (k = i | 256; k != 1; k >>= 1) {
+			c = c & 1 ? (c >> 1) ^ e : c >> 1;
+			if (k & 1)
+				c ^= e;
+		}
+		crc_32_tab[i] = c;
+	}
+}
+
+/*
+ * Check the magic number of the input file and update ofname if an
+ * original name was given and to_stdout is not set.
+ * Set inptr to the offset of the next byte to be processed.
+ */
+static void get_method()
+{
+	uchar flags;
+	char magic[2];  /* magic header */
+
+	magic[0] = get_byte();
+	magic[1] = get_byte();
+
+	method = -1;            /* unknown yet */
+	extended = pkzip = 0;
+	/* assume multiple members in gzip file except for record oriented I/O */
+
+	if (memcmp(magic, GZIP_MAGIC, 2) == 0
+	    || memcmp(magic, OLD_GZIP_MAGIC, 2) == 0) {
+		method = get_byte();
+		flags  = get_byte();
+		if (flags & ENCRYPTED)
+			error("Input is encrypted");
+		if (flags & CONTINUATION)
+			error("Multi part input");
+		if (flags & RESERVED)
+			error("Input has invalid flags");
+
+		(void) get_byte();      /* Get timestamp */
+		(void) get_byte();
+		(void) get_byte();
+		(void) get_byte();
+
+		(void) get_byte();      /* Ignore extra flags for the moment */
+		(void) get_byte();      /* Ignore OS type for the moment */
+
+		if (flags & EXTRA_FIELD) {
+			unsigned len = get_byte();
+			len |= get_byte() << 8;
+			while (len--)
+				(void) get_byte();
+		}
+
+		/* Discard file comment if any */
+		if (flags & COMMENT)
+			while (get_byte())
+				continue;
+
+	} else if (memcmp(magic, PKZIP_MAGIC, 2) == 0 && inptr == 2
+	    && memcmp(inbuf, PKZIP_MAGIC, 4) == 0) {
+		/*
+		 * To simplify the code, we support a zip file when alone only.
+		 * We are thus guaranteed that the entire local header fits in inbuf.
+		 */
+		inptr = 0;
+		check_zipfile();
+
+	} else if (memcmp(magic, PACK_MAGIC, 2) == 0)
+		error("packed input");
+	else if (memcmp(magic, LZW_MAGIC, 2) == 0)
+		error("compressed input");
+	if (method == -1)
+		error("Corrupted input");
+}
+
+void 
+decompress_kernel (void *dest)
+{
+	output_data = dest;
+	output_ptr = 0;
+
+	input_ptr = 0;
+
+	clear_bufs ();
+	makecrc ();
+	get_method ();
+	unzip ();
+}
diff --git a/sys/i386/boot/kzipboot/unzip.c b/sys/i386/boot/kzipboot/unzip.c
new file mode 100644
index 0000000..b3a9b5a
--- /dev/null
+++ b/sys/i386/boot/kzipboot/unzip.c
@@ -0,0 +1,175 @@
+/*
+ * 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"
+
+#ifdef USE_KERNEL_INFLATE
+#include <sys/types.h>
+#include <sys/inflate.h>
+#endif
+
+/* 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;
+}
+
+#ifdef USE_KERNEL_INFLATE
+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 */
+
+#endif
+
+/*
+ * 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;
+
+	crc = 0xffffffffL;      /* initialize crc */
+
+	if (pkzip && !extended) { /* crc and length at the end otherwise */
+		orig_crc = LG(inbuf + LOCCRC);
+		orig_len = LG(inbuf + LOCLEN);
+	}
+
+	/* Decompress */
+	if (method == DEFLATED)  {
+#ifdef USE_KERNEL_INFLATE
+		int res;
+		infl.gz_input = NextByte;
+		infl.gz_output = Flush;
+		infl.gz_slide = window;
+		res = inflate (&infl);
+#else
+		int res = inflate();
+#endif
+		if (res == 3)
+			error("out of memory");
+		else if (res != 0)
+			error("invalid compressed format");
+
+	} else if (pkzip && method == STORED) {
+		register ulong n = LG(inbuf + LOCLEN);
+
+		if (n != LG(inbuf + LOCSIZ))
+			error("length mismatch");
+		while (n--)
+			put_char(get_byte());
+	} else
+		error("internal error, invalid method");
+
+	/* 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");
+}