osloader.c

linux下从网卡远程启动

/**************************************************************************
OS loader

Author: Markus Gutschke ([e-mail])
  Date: Sep/95
Modifications: Ken Yap (for Etherboot/16)
  Doug Ambrisko (ELF and a.out support)
  Klaus Espenlaub (rewrote ELF and a.out (did it really work before?) support,
      added ELF Multiboot images).  Someone should merge the ELF and a.out
      loaders, as most of the code is now identical.  Maybe even NBI could be
      rewritten and merged into the generic loading framework.  This should
      save quite a few bytes of code if you have selected more than one format.
  Ken Yap (Jan 2001)
      Added support for linear entry addresses in tagged images,
      which allows a more efficient protected mode call instead of
      going to real mode and back. Also means entry addresses > 1 MB can
      be called.  Conditional on the LINEAR_EXEC_ADDR bit.
      Added support for Etherboot extension calls. Conditional on the
      TAGGED_PROGRAM_RETURNS bit. Implies LINEAR_EXEC_ADDR.
      Added support for non-MULTIBOOT ELF which also supports Etherboot
      extension calls. Conditional on the ELF_PROGRAM_RETURNS bit.

**************************************************************************/

/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2, or (at
 * your option) any later version.
 */

#include "etherboot.h"

struct os_entry_regs os_regs;

static struct ebinfo		loaderinfo = {
	VERSION_MAJOR, VERSION_MINOR,
	0
};

#define LOAD_DEBUG 0

static int prep_segment(unsigned long start, unsigned long mid, unsigned long end,
	unsigned long istart, unsigned long iend);
static void done(void);

#if defined(IMAGE_FREEBSD) && defined(ELF_IMAGE)
static void elf_freebsd_probe(void);
static void elf_freebsd_fixup_segment(void);
static void elf_freebsd_find_segment_end(void);
static int elf_freebsd_debug_loader(unsigned int offset);
static void elf_freebsd_boot(unsigned long entry);
#else
#define elf_freebsd_probe() do {} while(0)
#define elf_freebsd_fixup_segment()  do {} while(0)
#define elf_freebsd_find_segment_end() do {} while(0)
#define elf_freebsd_debug_loader(off) (0)
#define elf_freebsd_boot(entry) do {} while(0)
#endif
#if defined(IMAGE_FREEBSD) && defined(AOUT_IMAGE)
static void aout_freebsd_probe(void);
static void aout_freebsd_boot(void);
#else
#define aout_freebsd_probe() do {} while(0)
#define aout_freebsd_boot() do {} while(0)
#endif

#ifdef	IMAGE_MULTIBOOT
#include "../arch/i386/core/multiboot_loader.c"
#else
#define multiboot_probe(data, len) do {} while(0)
#define multiboot_boot(entry) do {} while(0)
#endif


#ifdef WINCE_IMAGE
#include "../arch/i386/core/wince_loader.c"
#endif

#ifdef AOUT_IMAGE
#include "../arch/i386/core/aout_loader.c"
#endif

#ifdef TAGGED_IMAGE
#include "../arch/i386/core/tagged_loader.c"
#endif

#if defined(ELF_IMAGE) || defined(ELF64_IMAGE)
#include "elf_loader.c"
#endif

#if defined(COFF_IMAGE) 
#include "../arch/e1/core/coff_loader.c"
#endif

#ifdef IMAGE_FREEBSD
#include "../arch/i386/core/freebsd_loader.c"
#endif

#ifdef SAFEBOOTMODE
extern void md5_put(unsigned int ch);
extern void md5_done(char * buf);
#include "rsaeuro.h"
#include "safeboot_key.h"
R_RSA_PUBLIC_KEY publicKey;
char encryptedString[MAX_RSA_MODULUS_LEN+2];
#endif

static void done(void)
{
#ifdef SAFEBOOTMODE
	unsigned char buf[16];
	unsigned char i;
	char decryptedString[256];
	int decryptedLength;
#endif
#ifdef	SIZEINDICATOR
	printf("K ");
#endif
	printf("done\n");
#ifdef SAFEBOOTMODE
	md5_done ( buf );
	//printf ( "MD5 checksum for downloaded image is: [" );
	//for ( i = 0; i < 16; ++i ) printf("%hhx", buf[i] );
	//printf ( "]\n" );
	// Now, decrypt the block from the file header
	for ( i = 0; i < 128; ++i ) {
		publicKey.exponent[i] = safemode_pubkey_d[i];
		publicKey.modulus[i]  = safemode_pubkey_m[i];
	}
	i = RSAPublicDecrypt(decryptedString, &decryptedLength, encryptedString,
	   64, &publicKey);
	if ( ( i != 0 ) || ( decryptedLength != 16 ) ) {
		  printf ( "\n\n*****************************************************\n" \
			     "*****  SafeBoot: RSA Crypto Algorithm Failure  ******\n" \
			     "***** (e.g. Signature does not match checksum) ******\n" \
			     "*****************************************************\n\n" \
			"This should be an alarm to the SysAdmin that something's\n" \
			"going extremely wrong in his/her ethernet!\n\n" \
			"To continue anyway, press >> C <<\n\n" );
			while ( ( 'C' & 0x1f ) != ( getchar () & 0x1f ) ) { ; }
	} else {
		decryptedLength = 0;
		for ( i = 0; i < 16; ++i ) {
			// printf ( " %hhx:%hhx", buf[i], decryptedString[i] );
			if ( buf[i] != *(unsigned char *)(decryptedString + i) ) decryptedLength = 1;
		}
		if ( decryptedLength != 0 ) {
		  printf ( "\n\n*****************************************************\n" \
			     "**** SafeBoot: VERIFICATION OF BOOT-IMAGE FAILED ****\n" \
			     "**** (e.g. image has been manipulated / changed) ****\n" \
			     "*****************************************************\n\n" \
			"This should be an alarm to the SysAdmin that something's\n" \
			"going extremely wrong in his/her ethernet!\n\n" \
			"To continue anyway, press >> C <<\n\n" );
			while ( ( 'C' & 0x1f ) != ( getchar () & 0x1f ) ) { ; }
		} else {
		  printf ( "\n\n****** SafeBoot Image-Verification SUCCESSFUL, Integrity established ******\n\n" );
		}
	}
		
#endif
	cleanup();
}

static int prep_segment(unsigned long start, unsigned long mid, unsigned long end,
	unsigned long istart __unused, unsigned long iend __unused)
{
	int fit, i;

#if LOAD_DEBUG
	printf ( "\nAbout to prepare segment [%lX,%lX)\n", start, end );
	sleep ( 3 );
#endif

	if (mid > end) {
		printf("filesz > memsz\n");
		return 0;
	}
	if ((end > virt_to_phys(_text)) && 
		(start < virt_to_phys(_end))) {
		printf("segment [%lX, %lX) overlaps etherboot [%lX, %lX)\n",
			start, end,
			virt_to_phys(_text), virt_to_phys(_end)
			);
		return 0;
	}
	if ((end > heap_ptr) && (start < heap_bot)) {
		printf("segment [%lX, %lX) overlaps heap [%lX, %lX)\n",
			start, end,
			heap_ptr, heap_bot
			);
		return 0;
	}
#ifdef PCBIOS
	if ((end > get_free_base_memory()) && (start < 0xa0000)) {
		printf("segment [%lX, %lX) overlaps used basemem [%lX, %lX)\n",
		       start, end, get_free_base_memory(), 0xa0000 );
		return 0;
	}
#endif
	fit = 0;
	for(i = 0; i < meminfo.map_count; i++) {
		unsigned long long r_start, r_end;
		if (meminfo.map[i].type != E820_RAM)
			continue;
		r_start = meminfo.map[i].addr;
		r_end = r_start + meminfo.map[i].size;
		if ((start >= r_start) && (end <= r_end)) {
			fit = 1;
			break;
		}
	}
	if (!fit) {
		printf("\nsegment [%lX,%lX) does not fit in any memory region\n",
			start, end);
#if LOAD_DEBUG
		printf("Memory regions(%d):\n", meminfo.map_count);
		for(i = 0; i < meminfo.map_count; i++) {
			unsigned long long r_start, r_end;
			if (meminfo.map[i].type != E820_RAM)
				continue;
			r_start = meminfo.map[i].addr;
			r_end = r_start + meminfo.map[i].size;
			printf("[%X%X, %X%X) type %d\n", 
				(unsigned long)(r_start >> 32),
				(unsigned long)r_start,
				(unsigned long)(r_end >> 32),
				(unsigned long)r_end,
				meminfo.map[i].type);
		}
#endif
		return 0;
	}
#if LOAD_DEBUG
	/* Zap the whole lot.  Do this so that if we're treading on
	 * anything, it shows up now, when the debug message is
	 * visible, rather than when we're partway through downloading
	 * the file.
	 *
	 * If you see an entire screen full of exclamation marks, then
	 * you've almost certainly written all over the display RAM.
	 * This is likely to happen if the status of the A20 line gets
	 * screwed up.  Of course, if this happens, it's a good bet
	 * that you've also trashed the whole of low memory, so expect
	 * interesting things to happen...
	 */
	memset(phys_to_virt(start), '!', mid - start);
#endif
	/* Zero the bss */
	if (end > mid) {
		memset(phys_to_virt(mid), 0, end - mid);
	}
	return 1;
}


#ifdef RAW_IMAGE
#warning "image_raw only works for x86 disks currently"
int bios_disk_dev = 0;
unsigned long raw_load_addr;
stattic unsigned long raw_download(
	unsinged char *data, unsinged int len, int eof);
static os_download_t raw_probe(unsigned char *data, unsigned int len)
{
	printf("(RAW)");
#warning "image_raw not complete"
	printf("FIXME image_raw not complete");
	raw_load_addr = 0x7c00; /* FIXME this varies by platform */
	return raw_download;
}
static unsigned long raw_download(
	unsigned char *data, unsigned int len, int eof)
{
	memcpy(phys_to_virt(raw_load_addr), data, len);
	raw_load_addr += len;
	if (!eof) {
		return 1;
	}
	done();
	gateA20_unset();
	/* FIXME merge the PXE loader && the X86_BOOTSECTOR_IMAGE
	 * loader.  They may need a little BIOS context information
	 * telling them how they booted, but otherwise they
	 * are essentially the same code.
	 */
	/* WARNING I need pxe parameter support... */
#warning "image_raw needs to pass pxe parameters"
	/* Set %edx to device number to emulate BIOS
	   Fortunately %edx is not used after this */
	__asm__("movl %0,%%edx" : : "g" (bios_disk_dev));
	xstart16(BOOTSECT, 0, 0);
	printf("Bootsector returned?");
	longjmp(restart_etherboot, -2);
	return 0;
}
#endif

/**************************************************************************
PROBE_IMAGE - Detect image file type
**************************************************************************/
os_download_t probe_image(unsigned char *data, unsigned int len)
{
	os_download_t os_download = 0;
#ifdef AOUT_IMAGE
	if (!os_download) os_download = aout_probe(data, len);
#endif
#ifdef ELF_IMAGE
	if (!os_download) os_download = elf32_probe(data, len);
#endif
#ifdef ELF64_IMAGE
	if (!os_download) os_download = elf64_probe(data, len);
#endif
#ifdef COFF_IMAGE
    if (!os_download) os_download = coff_probe(data, len);
#endif
#ifdef WINCE_IMAGE
	if (!os_download) os_download = wince_probe(data, len);
#endif
#ifdef TAGGED_IMAGE
	if (!os_download) os_download = tagged_probe(data, len);
#endif
#ifdef RAW_IMAGE
	if (!os_download) os_download = raw_probe(data, len);
#endif
	return os_download;
}

/**************************************************************************
LOAD_BLOCK - Try to load file
**************************************************************************/
int load_block(unsigned char *data, unsigned int block, unsigned int len, int eof)
{
	static os_download_t os_download;
	static sector_t skip_sectors;
	static unsigned int skip_bytes;
#ifdef SAFEBOOTMODE
	unsigned int i, j;
#endif
#ifdef	SIZEINDICATOR
	static int rlen = 0;

	if (block == 1)
	{
		rlen=len;
		printf("XXXX");
	}
	if (!(block % 4) || eof) {
		int size;
		size = ((block-1) * rlen + len) / 1024;

		putchar('\b');
		putchar('\b');
		putchar('\b');
		putchar('\b');

		putchar('0' + (size/1000)%10);
		putchar('0' + (size/100)%10);
		putchar('0' + (size/10)%10);
		putchar('0' + (size/1)%10);
	}
#endif
	if (block == 1)
	{
		skip_sectors = 0;
		skip_bytes = 0;
		os_download = probe_image(data, len);
		if (!os_download) {
			printf("error: not a valid image\n");
#if 0
			printf("block: %d len: %d\n", block, len);
			printf("%hhx %hhx %hhx %hhx %hhx %hhx %hhx %hhx %hhx\n",
				data[0], data[1], data[2], data[3],
				data[4], data[5], data[6], data[7]);
#endif
			return 0;
		}
#ifdef SAFEBOOTMODE
		if ( ( SAFEBOOTMODE & 0xf0 ) == 0 ) {
			if ( os_download != tagged_download ) {
		  	  printf ( "\n\n*****************************************************\n" \
			     "***** SafeBoot: LOADING UNSUPPORTED FILE FORMAT *****\n" \
			     "*****************************************************\n\n" \
			  "SafeBoot has been activated to only support NBI - Net\n" \
			  "Boot Images. You are downloading another filetype\n" \
			  "for which integrity check is not possible.\n\n" \
			  "To continue anyway, press >> C <<\n\n" );
			  while ( ( 'C' & 0x1f ) != ( getchar () & 0x1f ) ) { ; }
			}
		}
#endif
	} /* end of block zero processing */

	/* Either len is greater or the skip is greater */
	if ((skip_sectors > (len >> 9)) ||
		((skip_sectors == (len >> 9)) && (skip_bytes >= (len & 0x1ff)))) {
		/* If I don't have enough bytes borrow them from skip_sectors */
		if (skip_bytes < len) {
			skip_sectors -= (len - skip_bytes + 511) >> 9;
			skip_bytes += (len - skip_bytes + 511) & ~0x1ff;
		}
		skip_bytes -= len;
	}
	else {
		len -= (skip_sectors << 9) + skip_bytes;
		data += (skip_sectors << 9) + skip_bytes;
#ifdef SAFEBOOTMODE
		if ( ( SAFEBOOTMODE & 0xf0 ) == 0 ) {
			if ( ( block == 1 ) && ( len >= 446 ) ) j = 446; else j = len;
			for ( i = 0; i < j; ++i ) md5_put(*(unsigned char *)(data+i));
			if ( block == 1 ) {
				for ( i = 446; i < 510; ++i ) md5_put ( (unsigned char) 0 );
				for ( i = 510; i < len; ++i ) md5_put(*(unsigned char *)(data+i));
				for ( i = 0; i < 64; ++i ) encryptedString[i] = *(unsigned char*)(data+446+i);
			}
		}
#endif
		  skip_sectors = os_download(data, len, eof);
		skip_bytes = 0;
	}
	return 1;
}

/*
 * Local variables:
 *  c-basic-offset: 8
 * End:
 */