285 lines
7.2 KiB
C
285 lines
7.2 KiB
C
/*
|
|
* Example of use of user mode libqemu: launch a basic .com DOS
|
|
* executable
|
|
*/
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <inttypes.h>
|
|
#include <unistd.h>
|
|
#include <fcntl.h>
|
|
#include <sys/mman.h>
|
|
#include <signal.h>
|
|
#include <malloc.h>
|
|
|
|
#include "cpu.h"
|
|
|
|
//#define SIGTEST
|
|
|
|
int cpu_get_pic_interrupt(CPUState *env)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
uint64_t cpu_get_tsc(CPUState *env)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
|
|
unsigned long addr, unsigned int sel)
|
|
{
|
|
unsigned int e1, e2;
|
|
e1 = (addr & 0xffff) | (sel << 16);
|
|
e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
|
|
stl((uint8_t *)ptr, e1);
|
|
stl((uint8_t *)ptr + 4, e2);
|
|
}
|
|
|
|
uint64_t idt_table[256];
|
|
|
|
/* only dpl matters as we do only user space emulation */
|
|
static void set_idt(int n, unsigned int dpl)
|
|
{
|
|
set_gate(idt_table + n, 0, dpl, 0, 0);
|
|
}
|
|
|
|
void qemu_free(void *ptr)
|
|
{
|
|
free(ptr);
|
|
}
|
|
|
|
void *qemu_malloc(size_t size)
|
|
{
|
|
return malloc(size);
|
|
}
|
|
|
|
void *qemu_mallocz(size_t size)
|
|
{
|
|
void *ptr;
|
|
ptr = qemu_malloc(size);
|
|
if (!ptr)
|
|
return NULL;
|
|
memset(ptr, 0, size);
|
|
return ptr;
|
|
}
|
|
|
|
void *qemu_vmalloc(size_t size)
|
|
{
|
|
return memalign(4096, size);
|
|
}
|
|
|
|
void qemu_vfree(void *ptr)
|
|
{
|
|
free(ptr);
|
|
}
|
|
|
|
void qemu_printf(const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
va_start(ap, fmt);
|
|
vprintf(fmt, ap);
|
|
va_end(ap);
|
|
}
|
|
|
|
/* XXX: this is a bug in helper2.c */
|
|
int errno;
|
|
|
|
/**********************************************/
|
|
|
|
#define COM_BASE_ADDR 0x10100
|
|
|
|
void usage(void)
|
|
{
|
|
printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
|
|
"usage: qruncom file.com\n"
|
|
"user mode libqemu demo: run simple .com DOS executables\n");
|
|
exit(1);
|
|
}
|
|
|
|
static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
|
|
{
|
|
return (uint8_t *)((seg << 4) + (reg & 0xffff));
|
|
}
|
|
|
|
static inline void pushw(CPUState *env, int val)
|
|
{
|
|
env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
|
|
*(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
|
|
}
|
|
|
|
static void host_segv_handler(int host_signum, siginfo_t *info,
|
|
void *puc)
|
|
{
|
|
if (cpu_signal_handler(host_signum, info, puc)) {
|
|
return;
|
|
}
|
|
abort();
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
uint8_t *vm86_mem;
|
|
const char *filename;
|
|
int fd, ret, seg;
|
|
CPUState *env;
|
|
|
|
if (argc != 2)
|
|
usage();
|
|
filename = argv[1];
|
|
|
|
vm86_mem = mmap((void *)0x00000000, 0x110000,
|
|
PROT_WRITE | PROT_READ | PROT_EXEC,
|
|
MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
|
|
if (vm86_mem == MAP_FAILED) {
|
|
perror("mmap");
|
|
exit(1);
|
|
}
|
|
|
|
/* load the MSDOS .com executable */
|
|
fd = open(filename, O_RDONLY);
|
|
if (fd < 0) {
|
|
perror(filename);
|
|
exit(1);
|
|
}
|
|
ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256);
|
|
if (ret < 0) {
|
|
perror("read");
|
|
exit(1);
|
|
}
|
|
close(fd);
|
|
|
|
/* install exception handler for CPU emulator */
|
|
{
|
|
struct sigaction act;
|
|
|
|
sigfillset(&act.sa_mask);
|
|
act.sa_flags = SA_SIGINFO;
|
|
// act.sa_flags |= SA_ONSTACK;
|
|
|
|
act.sa_sigaction = host_segv_handler;
|
|
sigaction(SIGSEGV, &act, NULL);
|
|
sigaction(SIGBUS, &act, NULL);
|
|
}
|
|
|
|
// cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
|
|
|
|
env = cpu_init("qemu32");
|
|
|
|
cpu_x86_set_cpl(env, 3);
|
|
|
|
env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
|
|
/* NOTE: hflags duplicates some of the virtual CPU state */
|
|
env->hflags |= HF_PE_MASK | VM_MASK;
|
|
|
|
/* flags setup : we activate the IRQs by default as in user
|
|
mode. We also activate the VM86 flag to run DOS code */
|
|
env->eflags |= IF_MASK | VM_MASK;
|
|
|
|
/* init basic registers */
|
|
env->eip = 0x100;
|
|
env->regs[R_ESP] = 0xfffe;
|
|
seg = (COM_BASE_ADDR - 0x100) >> 4;
|
|
|
|
cpu_x86_load_seg_cache(env, R_CS, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
cpu_x86_load_seg_cache(env, R_SS, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
cpu_x86_load_seg_cache(env, R_DS, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
cpu_x86_load_seg_cache(env, R_ES, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
cpu_x86_load_seg_cache(env, R_FS, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
cpu_x86_load_seg_cache(env, R_GS, seg,
|
|
(seg << 4), 0xffff, 0);
|
|
|
|
/* exception support */
|
|
env->idt.base = (unsigned long)idt_table;
|
|
env->idt.limit = sizeof(idt_table) - 1;
|
|
set_idt(0, 0);
|
|
set_idt(1, 0);
|
|
set_idt(2, 0);
|
|
set_idt(3, 3);
|
|
set_idt(4, 3);
|
|
set_idt(5, 3);
|
|
set_idt(6, 0);
|
|
set_idt(7, 0);
|
|
set_idt(8, 0);
|
|
set_idt(9, 0);
|
|
set_idt(10, 0);
|
|
set_idt(11, 0);
|
|
set_idt(12, 0);
|
|
set_idt(13, 0);
|
|
set_idt(14, 0);
|
|
set_idt(15, 0);
|
|
set_idt(16, 0);
|
|
set_idt(17, 0);
|
|
set_idt(18, 0);
|
|
set_idt(19, 0);
|
|
|
|
/* put return code */
|
|
*seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
|
|
*seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
|
|
*seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
|
|
*seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
|
|
pushw(env, 0x0000);
|
|
|
|
/* the value of these registers seem to be assumed by pi_10.com */
|
|
env->regs[R_ESI] = 0x100;
|
|
env->regs[R_ECX] = 0xff;
|
|
env->regs[R_EBP] = 0x0900;
|
|
env->regs[R_EDI] = 0xfffe;
|
|
|
|
/* inform the emulator of the mmaped memory */
|
|
page_set_flags(0x00000000, 0x110000,
|
|
PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
|
|
|
|
for(;;) {
|
|
ret = cpu_x86_exec(env);
|
|
switch(ret) {
|
|
case EXCP0D_GPF:
|
|
{
|
|
int int_num, ah;
|
|
int_num = *(uint8_t *)(env->segs[R_CS].base + env->eip + 1);
|
|
if (int_num != 0x21)
|
|
goto unknown_int;
|
|
ah = (env->regs[R_EAX] >> 8) & 0xff;
|
|
switch(ah) {
|
|
case 0x00: /* exit */
|
|
exit(0);
|
|
case 0x02: /* write char */
|
|
{
|
|
uint8_t c = env->regs[R_EDX];
|
|
write(1, &c, 1);
|
|
}
|
|
break;
|
|
case 0x09: /* write string */
|
|
{
|
|
uint8_t c;
|
|
for(;;) {
|
|
c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
|
|
if (c == '$')
|
|
break;
|
|
write(1, &c, 1);
|
|
}
|
|
env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
|
|
}
|
|
break;
|
|
default:
|
|
unknown_int:
|
|
fprintf(stderr, "unsupported int 0x%02x\n", int_num);
|
|
cpu_dump_state(env, stderr, fprintf, 0);
|
|
// exit(1);
|
|
}
|
|
env->eip += 2;
|
|
}
|
|
break;
|
|
default:
|
|
fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
|
|
cpu_dump_state(env, stderr, fprintf, 0);
|
|
exit(1);
|
|
}
|
|
}
|
|
}
|