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 #include <malloc.h>
  14
  15 #include "cpu.h"
  16
  17 //#define SIGTEST
  18
  19 void cpu_outb(CPUState *env, int addr, int val)
  20 {
  21     fprintf(stderr, "outb: port=0x%04x, data=%02x\n", addr, val);
  22 }
  23
  24 void cpu_outw(CPUState *env, int addr, int val)
  25 {
  26     fprintf(stderr, "outw: port=0x%04x, data=%04x\n", addr, val);
  27 }
  28
  29 void cpu_outl(CPUState *env, int addr, int val)
  30 {
  31     fprintf(stderr, "outl: port=0x%04x, data=%08x\n", addr, val);
  32 }
  33
  34 int cpu_inb(CPUState *env, int addr)
  35 {
  36     fprintf(stderr, "inb: port=0x%04x\n", addr);
  37     return 0;
  38 }
  39
  40 int cpu_inw(CPUState *env, int addr)
  41 {
  42     fprintf(stderr, "inw: port=0x%04x\n", addr);
  43     return 0;
  44 }
  45
  46 int cpu_inl(CPUState *env, int addr)
  47 {
  48     fprintf(stderr, "inl: port=0x%04x\n", addr);
  49     return 0;
  50 }
  51
  52 int cpu_get_pic_interrupt(CPUState *env)
  53 {
  54     return -1;
  55 }
  56
  57 uint64_t cpu_get_tsc(CPUState *env)
  58 {
  59     return 0;
  60 }
  61
  62 static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
  63                      unsigned long addr, unsigned int sel)
  64 {
  65     unsigned int e1, e2;
  66     e1 = (addr & 0xffff) | (sel << 16);
  67     e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
  68     stl((uint8_t *)ptr, e1);
  69     stl((uint8_t *)ptr + 4, e2);
  70 }
  71
  72 uint64_t idt_table[256];
  73
  74 /* only dpl matters as we do only user space emulation */
  75 static void set_idt(int n, unsigned int dpl)
  76 {
  77     set_gate(idt_table + n, 0, dpl, 0, 0);
  78 }
  79
  80 void qemu_free(void *ptr)
  81 {
  82     free(ptr);
  83 }
  84
  85 void *qemu_malloc(size_t size)
  86 {
  87     return malloc(size);
  88 }
  89
  90 void *qemu_mallocz(size_t size)
  91 {
  92     void *ptr;
  93     ptr = qemu_malloc(size);
  94     if (!ptr)
  95         return NULL;
  96     memset(ptr, 0, size);
  97     return ptr;
  98 }
  99
 100 void *qemu_vmalloc(size_t size)
 101 {
 102     return memalign(4096, size);
 103 }
 104
 105 void qemu_vfree(void *ptr)
 106 {
 107     free(ptr);
 108 }
 109
 110 void qemu_printf(const char *fmt, ...)
 111 {
 112     va_list ap;
 113     va_start(ap, fmt);
 114     vprintf(fmt, ap);
 115     va_end(ap);
 116 }
 117
 118 /* XXX: this is a bug in helper2.c */
 119 int errno;
 120
 121 /**********************************************/
 122
 123 #define COM_BASE_ADDR    0x10100
 124
 125 void usage(void)
 126 {
 127     printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
 128            "usage: qruncom file.com\n"
 129            "user mode libqemu demo: run simple .com DOS executables\n");
 130     exit(1);
 131 }
 132
 133 static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
 134 {
 135     return (uint8_t *)((seg << 4) + (reg & 0xffff));
 136 }
 137
 138 static inline void pushw(CPUState *env, int val)
 139 {
 140     env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
 141     *(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
 142 }
 143
 144 static void host_segv_handler(int host_signum, siginfo_t *info,
 145                               void *puc)
 146 {
 147     if (cpu_signal_handler(host_signum, info, puc)) {
 148         return;
 149     }
 150     abort();
 151 }
 152
 153 int main(int argc, char **argv)
 154 {
 155     uint8_t *vm86_mem;
 156     const char *filename;
 157     int fd, ret, seg;
 158     CPUState *env;
 159
 160     if (argc != 2)
 161         usage();
 162     filename = argv[1];
 163
 164     vm86_mem = mmap((void *)0x00000000, 0x110000,
 165                     PROT_WRITE | PROT_READ | PROT_EXEC,
 166                     MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
 167     if (vm86_mem == MAP_FAILED) {
 168         perror("mmap");
 169         exit(1);
 170     }
 171
 172     /* load the MSDOS .com executable */
 173     fd = open(filename, O_RDONLY);
 174     if (fd < 0) {
 175         perror(filename);
 176         exit(1);
 177     }
 178     ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256);
 179     if (ret < 0) {
 180         perror("read");
 181         exit(1);
 182     }
 183     close(fd);
 184
 185     /* install exception handler for CPU emulator */
 186     {
 187         struct sigaction act;
 188
 189         sigfillset(&act.sa_mask);
 190         act.sa_flags = SA_SIGINFO;
 191         //        act.sa_flags |= SA_ONSTACK;
 192
 193         act.sa_sigaction = host_segv_handler;
 194         sigaction(SIGSEGV, &act, NULL);
 195         sigaction(SIGBUS, &act, NULL);
 196 #if defined (TARGET_I386) && defined(USE_CODE_COPY)
 197         sigaction(SIGFPE, &act, NULL);
 198 #endif
 199     }
 200
 201     //    cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
 202
 203     env = cpu_init();
 204
 205     /* disable code copy to simplify debugging */
 206     code_copy_enabled = 0;
 207
 208     /* set user mode state (XXX: should be done automatically by
 209        cpu_init ?) */
 210     env->user_mode_only = 1;
 211
 212     cpu_x86_set_cpl(env, 3);
 213
 214     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
 215     /* NOTE: hflags duplicates some of the virtual CPU state */
 216     env->hflags |= HF_PE_MASK | VM_MASK;
 217
 218     /* flags setup : we activate the IRQs by default as in user
 219        mode. We also activate the VM86 flag to run DOS code */
 220     env->eflags |= IF_MASK | VM_MASK;
 221
 222     /* init basic registers */
 223     env->eip = 0x100;
 224     env->regs[R_ESP] = 0xfffe;
 225     seg = (COM_BASE_ADDR - 0x100) >> 4;
 226
 227     cpu_x86_load_seg_cache(env, R_CS, seg,
 228                            (seg << 4), 0xffff, 0);
 229     cpu_x86_load_seg_cache(env, R_SS, seg,
 230                            (seg << 4), 0xffff, 0);
 231     cpu_x86_load_seg_cache(env, R_DS, seg,
 232                            (seg << 4), 0xffff, 0);
 233     cpu_x86_load_seg_cache(env, R_ES, seg,
 234                            (seg << 4), 0xffff, 0);
 235     cpu_x86_load_seg_cache(env, R_FS, seg,
 236                            (seg << 4), 0xffff, 0);
 237     cpu_x86_load_seg_cache(env, R_GS, seg,
 238                            (seg << 4), 0xffff, 0);
 239
 240     /* exception support */
 241     env->idt.base = (unsigned long)idt_table;
 242     env->idt.limit = sizeof(idt_table) - 1;
 243     set_idt(0, 0);
 244     set_idt(1, 0);
 245     set_idt(2, 0);
 246     set_idt(3, 3);
 247     set_idt(4, 3);
 248     set_idt(5, 3);
 249     set_idt(6, 0);
 250     set_idt(7, 0);
 251     set_idt(8, 0);
 252     set_idt(9, 0);
 253     set_idt(10, 0);
 254     set_idt(11, 0);
 255     set_idt(12, 0);
 256     set_idt(13, 0);
 257     set_idt(14, 0);
 258     set_idt(15, 0);
 259     set_idt(16, 0);
 260     set_idt(17, 0);
 261     set_idt(18, 0);
 262     set_idt(19, 0);
 263
 264     /* put return code */
 265     *seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
 266     *seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
 267     *seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
 268     *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
 269     pushw(env, 0x0000);
 270
 271     /* the value of these registers seem to be assumed by pi_10.com */
 272     env->regs[R_ESI] = 0x100;
 273     env->regs[R_ECX] = 0xff;
 274     env->regs[R_EBP] = 0x0900;
 275     env->regs[R_EDI] = 0xfffe;
 276
 277     /* inform the emulator of the mmaped memory */
 278     page_set_flags(0x00000000, 0x110000,
 279                    PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
 280
 281     for(;;) {
 282         ret = cpu_x86_exec(env);
 283         switch(ret) {
 284         case EXCP0D_GPF:
 285             {
 286                 int int_num, ah;
 287                 int_num = *(uint8_t *)(env->segs[R_CS].base + env->eip + 1);
 288                 if (int_num != 0x21)
 289                     goto unknown_int;
 290                 ah = (env->regs[R_EAX] >> 8) & 0xff;
 291                 switch(ah) {
 292                 case 0x00: /* exit */
 293                     exit(0);
 294                 case 0x02: /* write char */
 295                     {
 296                         uint8_t c = env->regs[R_EDX];
 297                         write(1, &c, 1);
 298                     }
 299                     break;
 300                 case 0x09: /* write string */
 301                     {
 302                         uint8_t c;
 303                         for(;;) {
 304                             c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
 305                             if (c == '$')
 306                                 break;
 307                             write(1, &c, 1);
 308                         }
 309                         env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
 310                     }
 311                     break;
 312                 default:
 313                 unknown_int:
 314                     fprintf(stderr, "unsupported int 0x%02x\n", int_num);
 315                     cpu_dump_state(env, stderr, fprintf, 0);
 316                     //                    exit(1);
 317                 }
 318                 env->eip += 2;
 319             }
 320             break;
 321         default:
 322             fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
 323             cpu_dump_state(env, stderr, fprintf, 0);
 324             exit(1);
 325         }
 326     }
 327 }