Archipelago » qemu

/*

 *  gemu main

 * 

 *  Copyright (c) 2003 Fabrice Bellard

 *

 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.

 */

#include <stdlib.h>

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <unistd.h>

#include "gemu.h"

#include "cpu-i386.h"

#define DEBUG_LOGFILE "/tmp/gemu.log"

FILE *logfile = NULL;

int loglevel;

unsigned long x86_stack_size;

unsigned long stktop;

void gemu_log(const char *fmt, ...)

{

    va_list ap;

    va_start(ap, fmt);

    vfprintf(stderr, fmt, ap);

    va_end(ap);

}

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

/* CPUX86 core interface */

void cpu_x86_outb(int addr, int val)

{

    fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);

}

void cpu_x86_outw(int addr, int val)

{

    fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);

}

void cpu_x86_outl(int addr, int val)

{

    fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);

}

int cpu_x86_inb(int addr)

{

    fprintf(stderr, "inb: port=0x%04x\n", addr);

    return 0;

}

int cpu_x86_inw(int addr)

{

    fprintf(stderr, "inw: port=0x%04x\n", addr);

    return 0;

}

int cpu_x86_inl(int addr)

{

    fprintf(stderr, "inl: port=0x%04x\n", addr);

    return 0;

}

/* default linux values for the selectors */

#define __USER_CS        (0x23)

#define __USER_DS        (0x2B)

void write_dt(void *ptr, unsigned long addr, unsigned long limit, 

              int seg32_bit)

{

    unsigned int e1, e2, limit_in_pages;

    limit_in_pages = 0;

    if (limit > 0xffff) {

        limit = limit >> 12;

        limit_in_pages = 1;

    }

    e1 = (addr << 16) | (limit & 0xffff);

    e2 = ((addr >> 16) & 0xff) | (addr & 0xff000000) | (limit & 0x000f0000);

    e2 |= limit_in_pages << 23; /* byte granularity */

    e2 |= seg32_bit << 22; /* 32 bit segment */

    stl((uint8_t *)ptr, e1);

    stl((uint8_t *)ptr + 4, e2);

}

uint64_t gdt_table[6];

void usage(void)

{

    printf("gemu version " GEMU_VERSION ", Copyright (c) 2003 Fabrice Bellard\n"

           "usage: gemu [-d] program [arguments...]\n"

           "Linux x86 emulator\n"

           );

    exit(1);

}

int main(int argc, char **argv)

{

    const char *filename;

    struct target_pt_regs regs1, *regs = &regs1;

    struct image_info info1, *info = &info1;

    CPUX86State *env;

    int optind;

    if (argc <= 1)

        usage();

    loglevel = 0;

    optind = 1;

    if (argv[optind] && !strcmp(argv[optind], "-d")) {

        loglevel = 1;

        optind++;

    }

    filename = argv[optind];

    /* init debug */

    if (loglevel) {

        logfile = fopen(DEBUG_LOGFILE, "w");

        if (!logfile) {

            perror(DEBUG_LOGFILE);

            exit(1);

        }

        setvbuf(logfile, NULL, _IOLBF, 0);

    }

    /* Zero out regs */

    memset(regs, 0, sizeof(struct target_pt_regs));

    /* Zero out image_info */

    memset(info, 0, sizeof(struct image_info));

    if(elf_exec(filename, argv+optind, environ, regs, info) != 0) {

        printf("Error loading %s\n", filename);

        exit(1);

    }

    if (loglevel) {

        fprintf(logfile, "start_brk   0x%08lx\n" , info->start_brk);

        fprintf(logfile, "end_code    0x%08lx\n" , info->end_code);

        fprintf(logfile, "start_code  0x%08lx\n" , info->start_code);

        fprintf(logfile, "end_data    0x%08lx\n" , info->end_data);

        fprintf(logfile, "start_stack 0x%08lx\n" , info->start_stack);

        fprintf(logfile, "brk         0x%08lx\n" , info->brk);

        fprintf(logfile, "esp         0x%08lx\n" , regs->esp);

        fprintf(logfile, "eip         0x%08lx\n" , regs->eip);

    }

    target_set_brk((char *)info->brk);

    syscall_init();

    env = cpu_x86_init();

    /* linux register setup */

    env->regs[R_EAX] = regs->eax;

    env->regs[R_EBX] = regs->ebx;

    env->regs[R_ECX] = regs->ecx;

    env->regs[R_EDX] = regs->edx;

    env->regs[R_ESI] = regs->esi;

    env->regs[R_EDI] = regs->edi;

    env->regs[R_EBP] = regs->ebp;

    env->regs[R_ESP] = regs->esp;

    env->eip = regs->eip;

    /* linux segment setup */

    env->gdt.base = (void *)gdt_table;

    env->gdt.limit = sizeof(gdt_table) - 1;

    write_dt(&gdt_table[__USER_CS >> 3], 0, 0xffffffff, 1);

    write_dt(&gdt_table[__USER_DS >> 3], 0, 0xffffffff, 1);

    cpu_x86_load_seg(env, R_CS, __USER_CS);

    cpu_x86_load_seg(env, R_DS, __USER_DS);

    cpu_x86_load_seg(env, R_ES, __USER_DS);

    cpu_x86_load_seg(env, R_SS, __USER_DS);

    cpu_x86_load_seg(env, R_FS, __USER_DS);

    cpu_x86_load_seg(env, R_GS, __USER_DS);

    for(;;) {

        int err;

        uint8_t *pc;

        err = cpu_x86_exec(env);

        pc = env->seg_cache[R_CS].base + env->eip;

        switch(err) {

        case EXCP0D_GPF:

            if (pc[0] == 0xcd && pc[1] == 0x80) {

                /* syscall */

                env->eip += 2;

                env->regs[R_EAX] = do_syscall(env, 

                                              env->regs[R_EAX], 

                                              env->regs[R_EBX],

                                              env->regs[R_ECX],

                                              env->regs[R_EDX],

                                              env->regs[R_ESI],

                                              env->regs[R_EDI],

                                              env->regs[R_EBP]);

            } else {

                goto trap_error;

            }

            break;

        default:

        trap_error:

            fprintf(stderr, "0x%08lx: Unknown exception %d, aborting\n", 

                    (long)pc, err);

            abort();

        }

    }

    return 0;

}