tests/qruncom.c

   1 /*
   2  * Example of use of user mode libqemu: launch a basic .com DOS
   3  * executable
   4  */
   5 #include <stdlib.h>
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <inttypes.h>
   9 #include <unistd.h>
  10 #include <fcntl.h>
  11 #include <sys/mman.h>
  12 #include <signal.h>
  13
  14 #include "cpu.h"
  15
  16 //#define SIGTEST
  17
  18 CPUState *cpu_single_env = NULL;
  19
  20 void cpu_outb(CPUState *env, int addr, int val)
  21 {
  22     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  23 }
  24
  25 void cpu_outw(CPUState *env, int addr, int val)
  26 {
  27     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  28 }
  29
  30 void cpu_outl(CPUState *env, int addr, int val)
  31 {
  32     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  33 }
  34
  35 int cpu_inb(CPUState *env, int addr)
  36 {
  37     fprintf(stderr, "inb: port=0x%04x\n", addr);
  38     return 0;
  39 }
  40
  41 int cpu_inw(CPUState *env, int addr)
  42 {
  43     fprintf(stderr, "inw: port=0x%04x\n", addr);
  44     return 0;
  45 }
  46
  47 int cpu_inl(CPUState *env, int addr)
  48 {
  49     fprintf(stderr, "inl: port=0x%04x\n", addr);
  50     return 0;
  51 }
  52
  53 int cpu_get_pic_interrupt(CPUState *env)
  54 {
  55     return -1;
  56 }
  57
  58 uint64_t cpu_get_tsc(CPUState *env)
  59 {
  60     return 0;
  61 }
  62
  63 static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
  64                      unsigned long addr, unsigned int sel)
  65 {
  66     unsigned int e1, e2;
  67     e1 = (addr & 0xffff) | (sel << 16);
  68     e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
  69     stl((uint8_t *)ptr, e1);
  70     stl((uint8_t *)ptr + 4, e2);
  71 }
  72
  73 uint64_t idt_table[256];
  74
  75 /* only dpl matters as we do only user space emulation */
  76 static void set_idt(int n, unsigned int dpl)
  77 {
  78     set_gate(idt_table + n, 0, dpl, 0, 0);
  79 }
  80
  81 void qemu_free(void *ptr)
  82 {
  83     free(ptr);
  84 }
  85
  86 void *qemu_malloc(size_t size)
  87 {
  88     return malloc(size);
  89 }
  90
  91 void qemu_printf(const char *fmt, ...)
  92 {
  93     va_list ap;
  94     va_start(ap, fmt);
  95     vprintf(fmt, ap);
  96     va_end(ap);
  97 }
  98
  99 /* XXX: this is a bug in helper2.c */
 100 int errno;
 101
 102 /**********************************************/
 103
 104 #define COM_BASE_ADDR    0x10100
 105
 106 void usage(void)
 107 {
 108     printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
 109            "usage: qruncom file.com\n"
 110            "user mode libqemu demo: run simple .com DOS executables\n");
 111     exit(1);
 112 }
 113
 114 static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
 115 {
 116     return (uint8_t *)((seg << 4) + (reg & 0xffff));
 117 }
 118
 119 static inline void pushw(CPUState *env, int val)
 120 {
 121     env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
 122     *(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
 123 }
 124
 125 static void host_segv_handler(int host_signum, siginfo_t *info,
 126                               void *puc)
 127 {
 128     if (cpu_signal_handler(host_signum, info, puc)) {
 129         return;
 130     }
 131     abort();
 132 }
 133
 134 int main(int argc, char **argv)
 135 {
 136     uint8_t *vm86_mem;
 137     const char *filename;
 138     int fd, ret, seg;
 139     CPUState *env;
 140
 141     if (argc != 2)
 142         usage();
 143     filename = argv[1];
 144
 145     vm86_mem = mmap((void *)0x00000000, 0x110000,
 146                     PROT_WRITE | PROT_READ | PROT_EXEC,
 147                     MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
 148     if (vm86_mem == MAP_FAILED) {
 149         perror("mmap");
 150         exit(1);
 151     }
 152
 153     /* load the MSDOS .com executable */
 154     fd = open(filename, O_RDONLY);
 155     if (fd < 0) {
 156         perror(filename);
 157         exit(1);
 158     }
 159     ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256);
 160     if (ret < 0) {
 161         perror("read");
 162         exit(1);
 163     }
 164     close(fd);
 165
 166     /* install exception handler for CPU emulator */
 167     {
 168         struct sigaction act;
 169
 170         sigfillset(&act.sa_mask);
 171         act.sa_flags = SA_SIGINFO;
 172         //        act.sa_flags |= SA_ONSTACK;
 173
 174         act.sa_sigaction = host_segv_handler;
 175         sigaction(SIGSEGV, &act, NULL);
 176         sigaction(SIGBUS, &act, NULL);
 177 #if defined (TARGET_I386) && defined(USE_CODE_COPY)
 178         sigaction(SIGFPE, &act, NULL);
 179 #endif
 180     }
 181
 182     //    cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
 183
 184     env = cpu_init();
 185
 186     /* disable code copy to simplify debugging */
 187     code_copy_enabled = 0;
 188
 189     /* set user mode state (XXX: should be done automatically by
 190        cpu_init ?) */
 191     env->user_mode_only = 1;
 192
 193     cpu_x86_set_cpl(env, 3);
 194
 195     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
 196     /* NOTE: hflags duplicates some of the virtual CPU state */
 197     env->hflags |= HF_PE_MASK | VM_MASK;
 198
 199     /* flags setup : we activate the IRQs by default as in user
 200        mode. We also activate the VM86 flag to run DOS code */
 201     env->eflags |= IF_MASK | VM_MASK;
 202
 203     /* init basic registers */
 204     env->eip = 0x100;
 205     env->regs[R_ESP] = 0xfffe;
 206     seg = (COM_BASE_ADDR - 0x100) >> 4;
 207
 208     cpu_x86_load_seg_cache(env, R_CS, seg,
 209                            (uint8_t *)(seg << 4), 0xffff, 0);
 210     cpu_x86_load_seg_cache(env, R_SS, seg,
 211                            (uint8_t *)(seg << 4), 0xffff, 0);
 212     cpu_x86_load_seg_cache(env, R_DS, seg,
 213                            (uint8_t *)(seg << 4), 0xffff, 0);
 214     cpu_x86_load_seg_cache(env, R_ES, seg,
 215                            (uint8_t *)(seg << 4), 0xffff, 0);
 216     cpu_x86_load_seg_cache(env, R_FS, seg,
 217                            (uint8_t *)(seg << 4), 0xffff, 0);
 218     cpu_x86_load_seg_cache(env, R_GS, seg,
 219                            (uint8_t *)(seg << 4), 0xffff, 0);
 220
 221     /* exception support */
 222     env->idt.base = (void *)idt_table;
 223     env->idt.limit = sizeof(idt_table) - 1;
 224     set_idt(0, 0);
 225     set_idt(1, 0);
 226     set_idt(2, 0);
 227     set_idt(3, 3);
 228     set_idt(4, 3);
 229     set_idt(5, 3);
 230     set_idt(6, 0);
 231     set_idt(7, 0);
 232     set_idt(8, 0);
 233     set_idt(9, 0);
 234     set_idt(10, 0);
 235     set_idt(11, 0);
 236     set_idt(12, 0);
 237     set_idt(13, 0);
 238     set_idt(14, 0);
 239     set_idt(15, 0);
 240     set_idt(16, 0);
 241     set_idt(17, 0);
 242     set_idt(18, 0);
 243     set_idt(19, 0);
 244
 245     /* put return code */
 246     *seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
 247     *seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
 248     *seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
 249     *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
 250     pushw(env, 0x0000);
 251
 252     /* the value of these registers seem to be assumed by pi_10.com */
 253     env->regs[R_ESI] = 0x100;
 254     env->regs[R_ECX] = 0xff;
 255     env->regs[R_EBP] = 0x0900;
 256     env->regs[R_EDI] = 0xfffe;
 257
 258     /* inform the emulator of the mmaped memory */
 259     page_set_flags(0x00000000, 0x110000,
 260                    PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
 261
 262     for(;;) {
 263         ret = cpu_x86_exec(env);
 264         switch(ret) {
 265         case EXCP0D_GPF:
 266             {
 267                 int int_num, ah;
 268                 int_num = *(env->segs[R_CS].base + env->eip + 1);
 269                 if (int_num != 0x21)
 270                     goto unknown_int;
 271                 ah = (env->regs[R_EAX] >> 8) & 0xff;
 272                 switch(ah) {
 273                 case 0x00: /* exit */
 274                     exit(0);
 275                 case 0x02: /* write char */
 276                     {
 277                         uint8_t c = env->regs[R_EDX];
 278                         write(1, &c, 1);
 279                     }
 280                     break;
 281                 case 0x09: /* write string */
 282                     {
 283                         uint8_t c;
 284                         for(;;) {
 285                             c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
 286                             if (c == '$')
 287                                 break;
 288                             write(1, &c, 1);
 289                         }
 290                         env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
 291                     }
 292                     break;
 293                 default:
 294                 unknown_int:
 295                     fprintf(stderr, "unsupported int 0x%02x\n", int_num);
 296                     cpu_dump_state(env, stderr, 0);
 297                     //                    exit(1);
 298                 }
 299                 env->eip += 2;
 300             }
 301             break;
 302         default:
 303             fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
 304             cpu_dump_state(env, stderr, 0);
 305             exit(1);
 306         }
 307     }
 308 }