454 lines
15 KiB
C
454 lines
15 KiB
C
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#ifdef HAVE_CONFIG_H
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#include "../config.h"
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#endif
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#include <ctype.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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/* for gettimeofday() */
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#include <sys/time.h>
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/* This code stems from syslinux-3.72/utils/isohybrid, a perl script
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under GPL which is Copyright 2002-2008 H. Peter Anvin.
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Line numbers in comments refer to the lines of that script.
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It has been analyzed and re-written in C language 2008 by Thomas Schmitt,
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and is now under the licenses to which H.Peter Anvin agreed:
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http://syslinux.zytor.com/archives/2008-November/011105.html
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Date: Mon, 10 Nov 2008 08:36:46 -0800
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From: H. Peter Anvin <hpa@zytor.com>
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I hereby give permission for this code, translated to the C language, to
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be released under either the LGPL or the MIT/ISC/2-clause BSD licenses
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or both, at your option.
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Sincerely, H. Peter Anvin
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In the context of GNU xorriso, this code is under GPLv3+ derived from LGPL.
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In the context of libisofs this code derives its matching free software
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license from above stem licenses, typically from LGPL.
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In case its generosity is needed, here is the 2-clause BSD license:
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make_isohybrid_mbr.c is copyright 2002-2008 H. Peter Anvin
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and 2008-2010 Thomas Schmitt
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED `AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
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AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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THE PROVIDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* A helper function. One could replace it by one or two macros. */
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static int lsb_to_buf(char **wpt, uint32_t value, int bits, int flag)
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{
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int b;
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for (b = 0; b < bits; b += 8)
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*((unsigned char *) ((*wpt)++)) = (value >> b) & 0xff;
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return (1);
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}
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/* ====================================================================== */
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/* Deprecated Function */
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/* ====================================================================== */
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/*
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* Create a MBR for an isohybrid enabled ISOLINUX boot image.
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*
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* It is assumed that the caller has verified the readiness of the boot image
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* by checking for 0xfb 0xc0 0x78 0x70 at bytes 0x40 to 0x43 of isolinux.bin.
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*
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* @param bin_lba The predicted LBA of isolinux.bin within the emerging ISO.
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* @param img_blocks The predicted number of 2048 byte blocks in the ISO.
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* It will get rounded up to full MBs and that many blocks
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* must really be written as ISO 9660 image.
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* @param mbr A buffer of at least 512 bytes to take the result which is
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* to be written as the very beginning of the ISO.
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* @param flag unused yet, submit 0
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* @return <0 = fatal, 0 = failed , 1 = ok , 2 = ok with size warning
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*/
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int make_isohybrid_mbr(int bin_lba, int *img_blocks, char *mbr, int flag)
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{
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/* According to H. Peter Anvin this binary code stems from
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syslinux-3.72/mbr/isohdpfx.S
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*/
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static int mbr_code_size = 271;
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static unsigned char mbr_code[271] = { 0xfa, 0x31, 0xc0, 0x8e, 0xd8, 0x8e,
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0xd0, 0xbc, 0x00, 0x7c, 0x89, 0xe6, 0x06, 0x57, 0x52, 0x8e, 0xc0,
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0xfb, 0xfc, 0xbf, 0x00, 0x06, 0xb9, 0x00, 0x01, 0xf3, 0xa5, 0xea,
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0x20, 0x06, 0x00, 0x00, 0x52, 0xb4, 0x41, 0xbb, 0xaa, 0x55, 0x31,
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0xc9, 0x30, 0xf6, 0xf9, 0xcd, 0x13, 0x72, 0x14, 0x81, 0xfb, 0x55,
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0xaa, 0x75, 0x0e, 0x83, 0xe1, 0x01, 0x74, 0x09, 0x66, 0xc7, 0x06,
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0xb4, 0x06, 0xb4, 0x42, 0xeb, 0x15, 0x5a, 0x51, 0xb4, 0x08, 0xcd,
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0x13, 0x83, 0xe1, 0x3f, 0x51, 0x0f, 0xb6, 0xc6,
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0x40, 0x50, 0xf7, 0xe1, 0x52, 0x50, 0xbb, 0x00, 0x7c, 0xb9, 0x04,
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0x00, 0x66, 0xa1, 0xb0, 0x07, 0xe8, 0x40, 0x00, 0x72, 0x74, 0x66,
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0x40, 0x80, 0xc7, 0x02, 0xe2, 0xf4, 0x66, 0x81, 0x3e, 0x40, 0x7c,
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0xfb, 0xc0, 0x78, 0x70, 0x75, 0x07, 0xfa, 0xbc, 0xf4, 0x7b, 0xe9,
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0xc6, 0x75, 0xe8, 0x79, 0x00, 0x69, 0x73, 0x6f, 0x6c, 0x69, 0x6e,
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0x75, 0x78, 0x2e, 0x62, 0x69, 0x6e, 0x20, 0x6d, 0x69, 0x73, 0x73,
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0x69, 0x6e, 0x67, 0x20, 0x6f, 0x72, 0x20, 0x63, 0x6f, 0x72, 0x72,
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0x75, 0x70, 0x74,
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0x2e, 0x0d, 0x0a, 0x66, 0x60, 0x66, 0x31, 0xd2, 0x66, 0x52, 0x66,
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0x50, 0x06, 0x53, 0x6a, 0x01, 0x6a, 0x10, 0x89, 0xe6, 0x66, 0xf7,
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0x36, 0xf0, 0x7b, 0xc0, 0xe4, 0x06, 0x88, 0xe1, 0x88, 0xc5, 0x92,
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0xf6, 0x36, 0xf6, 0x7b, 0x88, 0xc6, 0x08, 0xe1, 0x41, 0xb8, 0x01,
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0x02, 0x8a, 0x16, 0xfa, 0x7b, 0xcd, 0x13, 0x8d, 0x64, 0x10, 0x66,
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0x61, 0xc3, 0xe8, 0x1e, 0x00, 0x4f, 0x70, 0x65, 0x72, 0x61, 0x74,
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0x69, 0x6e, 0x67, 0x20, 0x73, 0x79, 0x73, 0x74, 0x65, 0x6d, 0x20,
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0x6c, 0x6f, 0x61,
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0x64, 0x20, 0x65, 0x72, 0x72, 0x6f, 0x72, 0x2e, 0x0d, 0x0a, 0x5e,
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0xac, 0xb4, 0x0e, 0x8a, 0x3e, 0x62, 0x04, 0xb3, 0x07, 0xcd, 0x10,
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0x3c, 0x0a, 0x75, 0xf1, 0xcd, 0x18, 0xf4, 0xeb, 0xfd };
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static int h = 64, s = 32;
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int i, warn_size = 0, id;
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char *wpt;
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off_t imgsize, cylsize, frac, padding, c, cc;
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/* For generating a weak random number */
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struct timeval tv;
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struct timezone tz;
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if (bin_lba < 0 || bin_lba >= (1 << 29))
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return (0); /* 1 TB limit of signed 32 bit addressing of 512 byte blocks */
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/*
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84: Gets size of image in bytes.
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89:
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*/
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imgsize = ((off_t) *img_blocks) * (off_t) 2048;
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/*
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90: Computes $padding, size of padded image and number $c of
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pseudo-cylinders ($h and $s are constants set in line 24).
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102: $cc is $c curbed to 1024.
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*/
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cylsize = h * s * 512;
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frac = imgsize % cylsize;
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padding = (frac > 0 ? cylsize - frac : 0);
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imgsize += padding;
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*img_blocks = imgsize / (off_t) 2048;
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c = imgsize / cylsize;
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if (c > 1024) {
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warn_size = 1;
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cc = 1024;
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} else
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cc = c;
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/*
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107: Brings the hex-encoded bytes from the file __END__ into
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113: the MBR buffer. (This function holds them in mbr_code[].)
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*/
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for (i = 0; i < mbr_code_size; i++)
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mbr[i] = mbr_code[i];
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/*
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118: Pads up to 432
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*/
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for (i = mbr_code_size; i < 432; i++)
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mbr[i] = 0;
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/* From here on use write cursor wpt */
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wpt = mbr + 432;
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/*
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120: Converts LBA of isolinux.bin to blocksize 512 and writes
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to buffer. Appends 4 zero bytes.
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*/
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lsb_to_buf(&wpt, bin_lba * 4, 32, 0);
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lsb_to_buf(&wpt, 0, 32, 0);
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/*
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121: I do not understand where $id should eventually come
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from. An environment variable ?
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125: Whatever, i use some 32-bit random value with no crypto strength.
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*/
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gettimeofday(&tv, &tz);
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id = 0xffffffff & (tv.tv_sec ^ (tv.tv_usec * 2000));
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/*
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126: Adds 4 id bytes and 2 zero bytes.
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*/
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lsb_to_buf(&wpt, id, 32, 0);
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lsb_to_buf(&wpt, 0, 16, 0);
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/*
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129: Composes 16 byte record from the parameters determined
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147: so far. Appends it to buffer and add 48 zero bytes.
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*/
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/* There are 4 "partition slots". Only the first is non-zero here.
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In the perl script, the fields are set in variables and then
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written to buffer. I omit the variables.
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*/
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/* 0x80 */
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lsb_to_buf(&wpt, 0x80, 8, 0);
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/* bhead */
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lsb_to_buf(&wpt, 0, 8, 0);
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/* bsect */
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lsb_to_buf(&wpt, 1, 8, 0);
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/* bcyl */
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lsb_to_buf(&wpt, 0, 8, 0);
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/* fstype */
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lsb_to_buf(&wpt, 0x83, 8, 0);
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/* ehead */
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lsb_to_buf(&wpt, h - 1, 8, 0);
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/* esect */
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lsb_to_buf(&wpt, s + (((cc - 1) & 0x300) >> 2), 8, 0);
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/* ecyl */
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lsb_to_buf(&wpt, (cc - 1) & 0xff, 8, 0);
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/* 0 */
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lsb_to_buf(&wpt, 0, 32, 0);
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/* psize */
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lsb_to_buf(&wpt, c * h * s, 32, 0);
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/* Fill the other three slots with zeros */
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for (i = 0; i < 3 * 4; i++)
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lsb_to_buf(&wpt, 0, 32, 0);
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/*
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148: Appends bytes 0x55 , 0xAA.
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*/
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lsb_to_buf(&wpt, 0x55, 8, 0);
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lsb_to_buf(&wpt, 0xaa, 8, 0);
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return (1);
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}
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/* ====================================================================== */
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/* The New MBR Producer */
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/* ====================================================================== */
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/* The new MBR producer for isohybrid is a slightly generalized version of
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the deprecated function make_isohybrid_mbr(). It complies to the urge
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of H.Peter Anvin not to hardcode MBR templates but rather to read a
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file from the Syslinux tree, and to patch it as was done with the old
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MBR producer.
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The old algorithm was clarified publicly by the following mail.
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Changes towards the old algorithm:
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- 512-byte LBA of boot image is extended to 64 bit (we stay with 32)
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- check for a magic number is now gone
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The new implementation tries to use similar terms as the mail in order
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to facilitate its future discussion with Syslinux developers.
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From hpa@zytor.com Thu Apr 1 08:32:52 2010
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Date: Wed, 31 Mar 2010 14:53:51 -0700
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From: H. Peter Anvin <hpa@zytor.com>
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To: For discussion of Syslinux and tftp-hpa <syslinux@zytor.com>
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Cc: Thomas Schmitt <scdbackup@gmx.net>
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Subject: Re: [syslinux] port syslinux isohybrid perl script to C
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[...]
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[me:]
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> Currently i lack of blob and prescriptions.
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The blobs are available in the Syslinux build tree under the names:
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mbr/isohdp[fp]x*.bin
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The default probably should be mbr/isohdppx.bin, but it's ultimately up
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to the user.
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User definable parameters:
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-> MBR ID (default random 32-bit number,
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or preserved from previous instance)
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-> Sector count (default 32, range 1-63)
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-> Head count (default 64, range 1-256)
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-> Partition offset (default 0, range 0-64)
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-> Partition number (default 1, range 1-4)
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-> Filesystem type (default 0x17, range 1-255)
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Note: the filesystem type is largely arbitrary, in theory it can be any
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value other than 0x00, 0x05, 0x0f, 0x85, 0xee, or 0xef. 0x17 ("Windows
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IFS Hidden") seems safeish, some people believe 0x83 (Linux) is better.
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Here is the prescriptions for how to install it:
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All numbers are littleendian. "word" means 16 bits, "dword" means 32
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bits, "qword" means 64 bits.
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Common subroutine LBA_to_CHS():
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s = (lba % sector_count) + 1
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t = (lba / sector_count)
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h = (t % head_count)
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c = (t / head_count)
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if (c >= 1024):
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c = 1023
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h = head_count
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s = sector_count
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s = s | ((c & 0x300) >> 2)
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c = c & 0xff
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write byte h
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write byte s
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write byte c
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Main:
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Pad image_size to a multiple of sector_count*head_count
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Use the input file unmodified for bytes 0..431
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write qword boot_lba # Offset 432
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write dword mbr_id # Offset 440
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write word 0 # Offset 444
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# Offset 446
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For each partition entry 1..4:
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if this_partition != partition_number:
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write 16 zero bytes
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else:
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write byte 0x80
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write LBA_to_CHS(partition_offset)
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write byte filesystem_type
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write LBA_to_CHS(image_size-1)
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write dword partition_offset
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write dword image_size
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# Offset 510
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write word 0xaa55
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Use the input file unmodified for bytes 512..32767
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(pad with zero as necessary)
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[...]
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-hpa
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*/
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static
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int lba512chs_to_buf(char **wpt, off_t lba, int head_count, int sector_count)
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{
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int s, t, h, c;
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s = (lba % sector_count) + 1;
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t = (lba / sector_count);
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h = (t % head_count);
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c = (t / head_count);
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if (c >= 1024) {
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c = 1023;
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h = head_count; /* >>> not -1 ? Limits head_count to 255 */
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s = sector_count;
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}
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s = s | ((c & 0x300) >> 2);
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c = c & 0xff;
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(*((unsigned char **) wpt))[0] = h;
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(*((unsigned char **) wpt))[1] = s;
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(*((unsigned char **) wpt))[2] = c;
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(*wpt)+= 3;
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return(1);
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}
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/*
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* @param flag bit0= make own random MBR Id from current time
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*/
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int make_isolinux_mbr(int32_t *img_blocks, uint32_t boot_lba,
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uint32_t mbr_id, int head_count, int sector_count,
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int part_offset, int part_number, int fs_type,
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uint8_t *buf, int flag)
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{
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uint32_t spc, id, part, nominal_part_size;
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off_t hd_img_blocks, hd_boot_lba;
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char *wpt;
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/* For generating a weak random number */
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struct timeval tv;
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struct timezone tz;
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/* Pad image_size to a multiple of sector_count*head_count
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*/
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spc = head_count * sector_count;
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hd_img_blocks = ((off_t) *img_blocks) * (off_t) 4;
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if (hd_img_blocks % spc) {
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hd_img_blocks += spc - (hd_img_blocks % spc);
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*img_blocks = hd_img_blocks / 4 + !!(hd_img_blocks % 4);
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}
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wpt = (char *) buf + 432;
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/* write qword boot_lba # Offset 432
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*/
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hd_boot_lba = ((off_t) boot_lba) * (off_t) 4;
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lsb_to_buf(&wpt, hd_boot_lba & 0xffffffff, 32, 0);
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lsb_to_buf(&wpt, hd_boot_lba >> 32, 32, 0);
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/* write dword mbr_id # Offset 440
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(here some 32-bit random value with no crypto strength)
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*/
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if (flag & 1) {
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gettimeofday(&tv, &tz);
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id = 0xffffffff & (tv.tv_sec ^ (tv.tv_usec * 2000));
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lsb_to_buf(&wpt, id, 32, 0);
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}
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/* write word 0 # Offset 444
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*/
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lsb_to_buf(&wpt, 0, 16, 0);
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/* # Offset 446
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*/
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for (part = 1 ; part <= 4; part++) {
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if (part != part_number) {
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/* if this_partition != partition_number: write 16 zero bytes */
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memset(wpt, 0, 16);
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wpt+= 16;
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continue;
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}
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/* write byte 0x80
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write LBA_to_CHS(partition_offset)
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write byte filesystem_type
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write LBA_to_CHS(image_size-1)
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write dword partition_offset
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write dword image_size
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*/
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lsb_to_buf(&wpt, 0x80, 8, 0);
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lba512chs_to_buf(&wpt, part_offset, head_count, sector_count);
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lsb_to_buf(&wpt, fs_type, 8, 0);
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lba512chs_to_buf(&wpt, hd_img_blocks - 1, head_count, sector_count);
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lsb_to_buf(&wpt, part_offset, 32, 0);
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if (hd_img_blocks - (off_t) part_offset > (off_t) 0xffffffff)
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nominal_part_size = 0xffffffff;
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else
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nominal_part_size = hd_img_blocks - (off_t) part_offset;
|
|
lsb_to_buf(&wpt, nominal_part_size, 32, 0);
|
|
}
|
|
|
|
/* write word 0xaa55 # Offset 510
|
|
*/
|
|
lsb_to_buf(&wpt, 0xaa55, 16, 0);
|
|
|
|
return(1);
|
|
}
|
|
|
|
|