util.c

读取bios DMI信息

/*
 * Common "util" functions
 * This file is part of the dmidecode project.
 *
 *   Copyright (C) 2002-2008 Jean Delvare <khali@linux-fr>
 *
 *   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 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *   For the avoidance of doubt the "preferred form" of this code is one which
 *   is in an open unpatent encumbered format. Where cryptographic key signing
 *   forms part of the process of creating an executable the information
 *   including keys needed to generate an equivalently functional executable
 *   are deemed to be part of the source code.
 */

#include <sys/types.h>
#include <sys/stat.h>

#include "config.h"

#ifdef USE_MMAP
#include <sys/mman.h>
#ifndef MAP_FAILED
#define MAP_FAILED ((void *) -1)
#endif /* !MAP_FAILED */
#endif /* USE MMAP */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>

#include "types.h"
#include "util.h"

#ifndef USE_MMAP
static int myread(int fd, u8 *buf, size_t count, const char *prefix)
{
	ssize_t r = 1;
	size_t r2 = 0;

	while (r2 != count && r != 0)
	{
		r = read(fd, buf + r2, count - r2);
		if (r == -1)
		{
			if (errno != EINTR)
			{
				close(fd);
				perror(prefix);
				return -1;
			}
		}
		else
			r2 += r;
	}

	if (r2 != count)
	{
		close(fd);
		fprintf(stderr, "%s: Unexpected end of file\n", prefix);
		return -1;
	}

	return 0;
}
#endif

int checksum(const u8 *buf, size_t len)
{
	u8 sum = 0;
	size_t a;

	for (a = 0; a < len; a++)
		sum += buf[a];
	return (sum == 0);
}

/*
 * Copy a physical memory chunk into a memory buffer.
 * This function allocates memory.
 */
#include <go32.h>
#include <sys/farptr.h>
void *mem_chunk(size_t base, size_t len, const char *devmem)
{
	void *p;
        size_t i;

        if((p=malloc(len))==NULL)
        {
                perror("malloc");
                return NULL;
        }
        
        _farsetsel(_dos_ds);
        for(i=0; i<len; i++)
        {
                *((char *)p+i)=_farnspeekb(base+i);
        }

	return p;
}

int write_dump(size_t base, size_t len, const void *data, const char *dumpfile, int add)
{
	FILE *f;

	f = fopen(dumpfile, add ? "r+b" : "wb");
	if (!f)
	{
		fprintf(stderr, "%s: ", dumpfile);
		perror("fopen");
		return -1;
	}

	if (fseek(f, base, SEEK_SET) != 0)
	{
		fprintf(stderr, "%s: ", dumpfile);
		perror("fseek");
		goto err_close;
	}

	if (fwrite(data, len, 1, f) != 1)
	{
		fprintf(stderr, "%s: ", dumpfile);
		perror("fwrite");
		goto err_close;
	}

	if (fclose(f))
	{
		fprintf(stderr, "%s: ", dumpfile);
		perror("fclose");
		return -1;
	}

	return 0;

err_close:
	fclose(f);
	return -1;
}