(2006-08-06) rescue-bootcd
This commit is contained in:
594
extra/syslinux-3.09/dos/syslinux.c
Normal file
594
extra/syslinux-3.09/dos/syslinux.c
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@@ -0,0 +1,594 @@
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#ident "$Id: syslinux.c,v 1.13 2004/12/28 22:51:44 hpa Exp $"
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/* ----------------------------------------------------------------------- *
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*
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* Copyright 1998-2004 H. Peter Anvin - All Rights Reserved
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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, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* syslinux.c - Linux installer program for SYSLINUX
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*
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* Hacked up for DOS.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include "mystuff.h"
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#include "syslinux.h"
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#include "libfat.h"
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const char *program = "syslinux"; /* Name of program */
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uint16_t dos_version;
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#ifdef DEBUG
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# define dprintf printf
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#else
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# define dprintf(...) ((void)0)
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#endif
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void __attribute__((noreturn)) usage(void)
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{
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puts("Usage: syslinux [-sfma] <drive>: [bootsecfile]\n");
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exit(1);
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}
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void unlock_device(int);
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void __attribute__((noreturn)) die(const char *msg)
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{
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unlock_device(0);
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puts("syslinux: ");
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puts(msg);
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putchar('\n');
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exit(1);
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}
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/*
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* read/write wrapper functions
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*/
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int creat(const char *filename, int mode)
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{
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uint16_t rv;
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uint8_t err;
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dprintf("creat(\"%s\", 0x%x)\n", filename, mode);
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rv = 0x3C00;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "c" (mode), "d" (filename));
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if ( err ) {
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dprintf("rv = %d\n", rv);
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die("cannot open ldlinux.sys");
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}
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return rv;
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}
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void close(int fd)
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{
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uint16_t rv = 0x3E00;
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dprintf("close(%d)\n", fd);
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asm volatile("int $0x21"
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: "+a" (rv)
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: "b" (fd));
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/* The only error MS-DOS returns for close is EBADF,
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and we really don't care... */
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}
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ssize_t write_file(int fd, const void *buf, size_t count)
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{
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uint16_t rv;
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ssize_t done = 0;
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uint8_t err;
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dprintf("write_file(%d,%p,%u)\n", fd, buf, count);
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while ( count ) {
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rv = 0x4000;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "b" (fd), "c" (count), "d" (buf));
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if ( err || rv == 0 )
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die("file write error");
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done += rv;
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count -= rv;
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}
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return done;
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}
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struct diskio {
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uint32_t startsector;
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uint16_t sectors;
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uint16_t bufoffs, bufseg;
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} __attribute__((packed));
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void write_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
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{
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uint8_t err;
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struct diskio dio;
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dprintf("write_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
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dio.startsector = sector;
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dio.sectors = nsecs;
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dio.bufoffs = (uintptr_t)buf;
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asm("movw %%ds,%0" : "=m" (dio.bufseg));
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asm volatile("int $0x26 ; setc %0 ; popfw"
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: "=abcdm" (err)
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: "a" (drive-1), "b" (&dio), "c" (-1), "d" (buf));
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if ( err )
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die("sector write error");
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}
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void read_device(int drive, const void *buf, size_t nsecs, unsigned int sector)
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{
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uint8_t err;
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struct diskio dio;
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dprintf("read_device(%d,%p,%u,%u)\n", drive, buf, nsecs, sector);
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dio.startsector = sector;
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dio.sectors = nsecs;
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dio.bufoffs = (uintptr_t)buf;
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asm("movw %%ds,%0" : "=m" (dio.bufseg));
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asm volatile("int $0x25 ; setc %0 ; popfw"
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: "=abcdm" (err)
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: "a" (drive-1), "b" (&dio), "c" (-1), "d" (buf));
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if ( err )
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die("sector read error");
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}
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/* Both traditional DOS and FAT32 DOS return this structure, but
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FAT32 return a lot more data, so make sure we have plenty of space */
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struct deviceparams {
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uint8_t specfunc;
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uint8_t devtype;
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uint16_t devattr;
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uint16_t cylinders;
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uint8_t mediatype;
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uint16_t bytespersec;
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uint8_t secperclust;
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uint16_t ressectors;
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uint8_t fats;
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uint16_t rootdirents;
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uint16_t sectors;
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uint8_t media;
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uint16_t fatsecs;
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uint16_t secpertrack;
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uint16_t heads;
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uint32_t hiddensecs;
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uint32_t hugesectors;
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uint8_t lotsofpadding[224];
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} __attribute__((packed));
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uint32_t get_partition_offset(int drive)
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{
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uint8_t err;
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uint16_t rv;
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struct deviceparams dp;
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dp.specfunc = 1; /* Get current information */
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "b" (drive), "c" (0x0860), "d" (&dp));
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if ( !err )
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return dp.hiddensecs;
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "b" (drive), "c" (0x4860), "d" (&dp));
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if ( !err )
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return dp.hiddensecs;
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die("could not find partition start offset");
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}
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struct rwblock {
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uint8_t special;
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uint16_t head;
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uint16_t cylinder;
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uint16_t firstsector;
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uint16_t sectors;
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uint16_t bufferoffset;
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uint16_t bufferseg;
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} __attribute__((packed));
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static struct rwblock mbr = {
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.special = 0,
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.head = 0,
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.cylinder = 0,
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.firstsector = 0, /* MS-DOS, unlike the BIOS, zero-base sectors */
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.sectors = 1,
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.bufferoffset = 0,
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.bufferseg = 0
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};
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void write_mbr(int drive, const void *buf)
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{
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uint16_t rv;
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uint8_t err;
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dprintf("write_mbr(%d,%p)\n", drive, buf);
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mbr.bufferoffset = (uintptr_t)buf;
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asm("movw %%ds,%0" : "=m" (mbr.bufferseg));
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "c" (0x0841), "d" (&mbr), "b" (drive));
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if ( !err )
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return;
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "c" (0x4841), "d" (&mbr), "b" (drive));
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if ( err )
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die("mbr write error");
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}
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void read_mbr(int drive, const void *buf)
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{
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uint16_t rv;
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uint8_t err;
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dprintf("read_mbr(%d,%p)\n", drive, buf);
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mbr.bufferoffset = (uintptr_t)buf;
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asm("movw %%ds,%0" : "=m" (mbr.bufferseg));
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "c" (0x0861), "d" (&mbr), "b" (drive));
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if ( !err )
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return;
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "c" (0x4861), "d" (&mbr), "b" (drive));
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if ( err )
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die("mbr read error");
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}
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/* This call can legitimately fail, and we don't care, so ignore error return */
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void set_attributes(const char *file, int attributes)
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{
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uint16_t rv = 0x4301;
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dprintf("set_attributes(\"%s\", 0x%02x)\n", file, attributes);
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asm volatile("int $0x21"
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: "+a" (rv)
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: "c" (attributes), "d" (file));
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}
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/*
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* Version of the read_device function suitable for libfat
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*/
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int libfat_xpread(intptr_t pp, void *buf, size_t secsize, libfat_sector_t sector)
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{
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read_device(pp, buf, 1, sector);
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return secsize;
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}
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static inline void get_dos_version(void)
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{
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uint16_t ver = 0x3001;
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asm("int $0x21 ; xchgb %%ah,%%al" : "+a" (ver) : : "ebx", "ecx");
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dos_version = ver;
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dprintf("DOS version %d.%d\n", (dos_version >> 8), dos_version & 0xff);
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}
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/* The locking interface relies on static variables. A massive hack :( */
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static uint16_t lock_level;
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static inline void set_lock_device(uint8_t device)
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{
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lock_level = device;
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}
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void lock_device(int level)
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{
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uint16_t rv;
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uint8_t err;
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uint16_t lock_call;
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if ( dos_version < 0x0700 )
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return; /* Win9x/NT only */
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#if 0
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/* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
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lock_call = (dos_version >= 0x0710) ? 0x484A : 0x084A;
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#else
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lock_call = 0x084A; /* MSDN says this is OK for all filesystems */
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#endif
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while ( (lock_level >> 8) < level ) {
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uint16_t new_level = lock_level + 0x0100;
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dprintf("Trying lock %04x...\n", new_level);
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rv = 0x444d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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: "b" (new_level), "c" (lock_call), "d"(0x0001));
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if ( err ) {
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/* rv == 0x0001 means this call is not supported, if so we
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assume locking isn't needed (e.g. Win9x in DOS-only mode) */
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if ( rv == 0x0001 )
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return;
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else
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die("could not lock device");
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}
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lock_level = new_level;
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}
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return;
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}
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||||
|
||||
void unlock_device(int level)
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||||
{
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uint16_t rv;
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uint8_t err;
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uint16_t unlock_call;
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||||
|
||||
if ( dos_version < 0x0700 )
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return; /* Win9x/NT only */
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|
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#if 0
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/* DOS 7.10 = Win95 OSR2 = first version with FAT32 */
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unlock_call = (dos_version >= 0x0710) ? 0x486A : 0x086A;
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||||
#else
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unlock_call = 0x086A; /* MSDN says this is OK for all filesystems */
|
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#endif
|
||||
|
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while ( (lock_level >> 8) > level ) {
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||||
uint16_t new_level = lock_level - 0x0100;
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rv = 0x440d;
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asm volatile("int $0x21 ; setc %0"
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: "=abcdm" (err), "+a" (rv)
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||||
: "b" (new_level), "c" (unlock_call));
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||||
lock_level = new_level;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
* This function does any desired MBR manipulation; called with the device lock held.
|
||||
*/
|
||||
struct mbr_entry {
|
||||
uint8_t active; /* Active flag */
|
||||
uint8_t bhead; /* Begin head */
|
||||
uint8_t bsector; /* Begin sector */
|
||||
uint8_t bcylinder; /* Begin cylinder */
|
||||
uint8_t filesystem; /* Filesystem value */
|
||||
uint8_t ehead; /* End head */
|
||||
uint8_t esector; /* End sector */
|
||||
uint8_t ecylinder; /* End cylinder */
|
||||
uint32_t startlba; /* Start sector LBA */
|
||||
uint32_t sectors; /* Length in sectors */
|
||||
} __attribute__((packed));
|
||||
|
||||
static void adjust_mbr(int device, int writembr, int set_active)
|
||||
{
|
||||
static unsigned char sectbuf[512];
|
||||
int i;
|
||||
|
||||
if ( !writembr && !set_active )
|
||||
return; /* Nothing to do */
|
||||
|
||||
read_mbr(device, sectbuf);
|
||||
|
||||
if ( writembr ) {
|
||||
memcpy(sectbuf, syslinux_mbr, syslinux_mbr_len);
|
||||
*(uint16_t *)(sectbuf+510) = 0xaa55;
|
||||
}
|
||||
|
||||
if ( set_active ) {
|
||||
uint32_t offset = get_partition_offset(device);
|
||||
struct mbr_entry *me = (struct mbr_entry *)(sectbuf+446);
|
||||
int found = 0;
|
||||
|
||||
for ( i = 0 ; i < 4 ; i++ ) {
|
||||
if ( me->startlba == offset ) {
|
||||
me->active = 0x80;
|
||||
found++;
|
||||
} else {
|
||||
me->active = 0;
|
||||
}
|
||||
me++;
|
||||
}
|
||||
|
||||
if ( found < 1 ) {
|
||||
die("partition not found");
|
||||
} else if ( found > 1 ) {
|
||||
die("multiple aliased partitions found");
|
||||
}
|
||||
}
|
||||
|
||||
write_mbr(device, sectbuf);
|
||||
}
|
||||
|
||||
int main(int argc, char *argv[])
|
||||
{
|
||||
static unsigned char sectbuf[512];
|
||||
int dev_fd, fd;
|
||||
static char ldlinux_name[] = "@:\\LDLINUX.SYS";
|
||||
char **argp, *opt;
|
||||
int force = 0; /* -f (force) option */
|
||||
struct libfat_filesystem *fs;
|
||||
libfat_sector_t s, *secp, sectors[65]; /* 65 is maximum possible */
|
||||
int32_t ldlinux_cluster;
|
||||
int nsectors;
|
||||
const char *device = NULL, *bootsecfile = NULL;
|
||||
const char *errmsg;
|
||||
int i;
|
||||
int writembr = 0; /* -m (write MBR) option */
|
||||
int set_active = 0; /* -a (set partition active) option */
|
||||
|
||||
dprintf("argv = %p\n", argv);
|
||||
for ( i = 0 ; i <= argc ; i++ )
|
||||
dprintf("argv[%d] = %p = \"%s\"\n", i, argv[i], argv[i]);
|
||||
|
||||
(void)argc; /* Unused */
|
||||
|
||||
get_dos_version();
|
||||
|
||||
for ( argp = argv+1 ; *argp ; argp++ ) {
|
||||
if ( **argp == '-' ) {
|
||||
opt = *argp + 1;
|
||||
if ( !*opt )
|
||||
usage();
|
||||
|
||||
while ( *opt ) {
|
||||
switch ( *opt ) {
|
||||
case 's': /* Use "safe, slow and stupid" code */
|
||||
syslinux_make_stupid();
|
||||
break;
|
||||
case 'f': /* Force install */
|
||||
force = 1;
|
||||
break;
|
||||
case 'm': /* Write MBR */
|
||||
writembr = 1;
|
||||
break;
|
||||
case 'a': /* Set partition active */
|
||||
set_active = 1;
|
||||
break;
|
||||
default:
|
||||
usage();
|
||||
}
|
||||
opt++;
|
||||
}
|
||||
} else {
|
||||
if ( bootsecfile )
|
||||
usage();
|
||||
else if ( device )
|
||||
bootsecfile = *argp;
|
||||
else
|
||||
device = *argp;
|
||||
}
|
||||
}
|
||||
|
||||
if ( !device )
|
||||
usage();
|
||||
|
||||
/*
|
||||
* Figure out which drive we're talking to
|
||||
*/
|
||||
dev_fd = (device[0] & ~0x20) - 0x40;
|
||||
if ( dev_fd < 1 || dev_fd > 26 || device[1] != ':' || device[2] )
|
||||
usage();
|
||||
|
||||
set_lock_device(dev_fd);
|
||||
|
||||
lock_device(2); /* Make sure we can lock the device */
|
||||
read_device(dev_fd, sectbuf, 1, 0);
|
||||
unlock_device(1);
|
||||
|
||||
/*
|
||||
* Check to see that what we got was indeed an MS-DOS boot sector/superblock
|
||||
*/
|
||||
if( (errmsg = syslinux_check_bootsect(sectbuf)) ) {
|
||||
unlock_device(0);
|
||||
puts(errmsg);
|
||||
putchar('\n');
|
||||
exit(1);
|
||||
}
|
||||
|
||||
ldlinux_name[0] = dev_fd | 0x40;
|
||||
|
||||
set_attributes(ldlinux_name, 0);
|
||||
fd = creat(ldlinux_name, 0x07); /* SYSTEM HIDDEN READONLY */
|
||||
write_file(fd, syslinux_ldlinux, syslinux_ldlinux_len);
|
||||
close(fd);
|
||||
|
||||
/*
|
||||
* Now, use libfat to create a block map. This probably
|
||||
* should be changed to use ioctl(...,FIBMAP,...) since
|
||||
* this is supposed to be a simple, privileged version
|
||||
* of the installer.
|
||||
*/
|
||||
lock_device(2);
|
||||
fs = libfat_open(libfat_xpread, dev_fd);
|
||||
ldlinux_cluster = libfat_searchdir(fs, 0, "LDLINUX SYS", NULL);
|
||||
secp = sectors;
|
||||
nsectors = 0;
|
||||
s = libfat_clustertosector(fs, ldlinux_cluster);
|
||||
while ( s && nsectors < 65 ) {
|
||||
*secp++ = s;
|
||||
nsectors++;
|
||||
s = libfat_nextsector(fs, s);
|
||||
}
|
||||
libfat_close(fs);
|
||||
|
||||
/*
|
||||
* Patch ldlinux.sys and the boot sector
|
||||
*/
|
||||
syslinux_patch(sectors, nsectors);
|
||||
|
||||
/*
|
||||
* Write the now-patched first sector of ldlinux.sys
|
||||
*/
|
||||
lock_device(3);
|
||||
write_device(dev_fd, syslinux_ldlinux, 1, sectors[0]);
|
||||
|
||||
/*
|
||||
* Muck with the MBR, if desired, while we hold the lock
|
||||
*/
|
||||
adjust_mbr(dev_fd, writembr, set_active);
|
||||
|
||||
/*
|
||||
* To finish up, write the boot sector
|
||||
*/
|
||||
|
||||
/* Read the superblock again since it might have changed while mounted */
|
||||
read_device(dev_fd, sectbuf, 1, 0);
|
||||
|
||||
/* Copy the syslinux code into the boot sector */
|
||||
syslinux_make_bootsect(sectbuf);
|
||||
|
||||
/* Write new boot sector */
|
||||
if ( bootsecfile ) {
|
||||
unlock_device(0);
|
||||
fd = creat(bootsecfile, 0x20); /* ARCHIVE */
|
||||
write_file(fd, sectbuf, 512);
|
||||
close(fd);
|
||||
} else {
|
||||
write_device(dev_fd, sectbuf, 1, 0);
|
||||
unlock_device(0);
|
||||
}
|
||||
|
||||
/* Done! */
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user