File:  [Qemu by Fabrice Bellard] / qemu / tests / qruncom.c
Revision 1.1.1.6 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 18:25:22 2018 UTC (3 years, 5 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu1000, qemu0151, qemu0150, qemu0141, qemu0140, qemu0130, HEAD
qemu 0.13.0

    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: int cpu_get_pic_interrupt(CPUState *env)
   20: {
   21:     return -1;
   22: }
   23: 
   24: uint64_t cpu_get_tsc(CPUState *env)
   25: {
   26:     return 0;
   27: }
   28: 
   29: static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
   30:                      unsigned long addr, unsigned int sel)
   31: {
   32:     unsigned int e1, e2;
   33:     e1 = (addr & 0xffff) | (sel << 16);
   34:     e2 = (addr & 0xffff0000) | 0x8000 | (dpl << 13) | (type << 8);
   35:     stl((uint8_t *)ptr, e1);
   36:     stl((uint8_t *)ptr + 4, e2);
   37: }
   38: 
   39: uint64_t idt_table[256];
   40: 
   41: /* only dpl matters as we do only user space emulation */
   42: static void set_idt(int n, unsigned int dpl)
   43: {
   44:     set_gate(idt_table + n, 0, dpl, 0, 0);
   45: }
   46: 
   47: void qemu_free(void *ptr)
   48: {
   49:     free(ptr);
   50: }
   51: 
   52: void *qemu_malloc(size_t size)
   53: {
   54:     return malloc(size);
   55: }
   56: 
   57: void *qemu_mallocz(size_t size)
   58: {
   59:     void *ptr;
   60:     ptr = qemu_malloc(size);
   61:     if (!ptr)
   62:         return NULL;
   63:     memset(ptr, 0, size);
   64:     return ptr;
   65: }
   66: 
   67: void *qemu_vmalloc(size_t size)
   68: {
   69:     return memalign(4096, size);
   70: }
   71: 
   72: void qemu_vfree(void *ptr)
   73: {
   74:     free(ptr);
   75: }
   76: 
   77: void qemu_printf(const char *fmt, ...)
   78: {
   79:     va_list ap;
   80:     va_start(ap, fmt);
   81:     vprintf(fmt, ap);
   82:     va_end(ap);
   83: }
   84: 
   85: /* XXX: this is a bug in helper2.c */
   86: int errno;
   87: 
   88: /**********************************************/
   89: 
   90: #define COM_BASE_ADDR    0x10100
   91: 
   92: static void usage(void)
   93: {
   94:     printf("qruncom version 0.1 (c) 2003 Fabrice Bellard\n"
   95:            "usage: qruncom file.com\n"
   96:            "user mode libqemu demo: run simple .com DOS executables\n");
   97:     exit(1);
   98: }
   99: 
  100: static inline uint8_t *seg_to_linear(unsigned int seg, unsigned int reg)
  101: {
  102:     return (uint8_t *)((seg << 4) + (reg & 0xffff));
  103: }
  104: 
  105: static inline void pushw(CPUState *env, int val)
  106: {
  107:     env->regs[R_ESP] = (env->regs[R_ESP] & ~0xffff) | ((env->regs[R_ESP] - 2) & 0xffff);
  108:     *(uint16_t *)seg_to_linear(env->segs[R_SS].selector, env->regs[R_ESP]) = val;
  109: }
  110: 
  111: static void host_segv_handler(int host_signum, siginfo_t *info,
  112:                               void *puc)
  113: {
  114:     if (cpu_signal_handler(host_signum, info, puc)) {
  115:         return;
  116:     }
  117:     abort();
  118: }
  119: 
  120: int main(int argc, char **argv)
  121: {
  122:     uint8_t *vm86_mem;
  123:     const char *filename;
  124:     int fd, ret, seg;
  125:     CPUState *env;
  126: 
  127:     if (argc != 2)
  128:         usage();
  129:     filename = argv[1];
  130: 
  131:     vm86_mem = mmap((void *)0x00000000, 0x110000,
  132:                     PROT_WRITE | PROT_READ | PROT_EXEC,
  133:                     MAP_FIXED | MAP_ANON | MAP_PRIVATE, -1, 0);
  134:     if (vm86_mem == MAP_FAILED) {
  135:         perror("mmap");
  136:         exit(1);
  137:     }
  138: 
  139:     /* load the MSDOS .com executable */
  140:     fd = open(filename, O_RDONLY);
  141:     if (fd < 0) {
  142:         perror(filename);
  143:         exit(1);
  144:     }
  145:     ret = read(fd, vm86_mem + COM_BASE_ADDR, 65536 - 256);
  146:     if (ret < 0) {
  147:         perror("read");
  148:         exit(1);
  149:     }
  150:     close(fd);
  151: 
  152:     /* install exception handler for CPU emulator */
  153:     {
  154:         struct sigaction act;
  155: 
  156:         sigfillset(&act.sa_mask);
  157:         act.sa_flags = SA_SIGINFO;
  158:         //        act.sa_flags |= SA_ONSTACK;
  159: 
  160:         act.sa_sigaction = host_segv_handler;
  161:         sigaction(SIGSEGV, &act, NULL);
  162:         sigaction(SIGBUS, &act, NULL);
  163:     }
  164: 
  165:     //    cpu_set_log(CPU_LOG_TB_IN_ASM | CPU_LOG_TB_OUT_ASM | CPU_LOG_EXEC);
  166: 
  167:     env = cpu_init("qemu32");
  168: 
  169:     cpu_x86_set_cpl(env, 3);
  170: 
  171:     env->cr[0] = CR0_PG_MASK | CR0_WP_MASK | CR0_PE_MASK;
  172:     /* NOTE: hflags duplicates some of the virtual CPU state */
  173:     env->hflags |= HF_PE_MASK | VM_MASK;
  174: 
  175:     /* flags setup : we activate the IRQs by default as in user
  176:        mode. We also activate the VM86 flag to run DOS code */
  177:     env->eflags |= IF_MASK | VM_MASK;
  178: 
  179:     /* init basic registers */
  180:     env->eip = 0x100;
  181:     env->regs[R_ESP] = 0xfffe;
  182:     seg = (COM_BASE_ADDR - 0x100) >> 4;
  183: 
  184:     cpu_x86_load_seg_cache(env, R_CS, seg,
  185:                            (seg << 4), 0xffff, 0);
  186:     cpu_x86_load_seg_cache(env, R_SS, seg,
  187:                            (seg << 4), 0xffff, 0);
  188:     cpu_x86_load_seg_cache(env, R_DS, seg,
  189:                            (seg << 4), 0xffff, 0);
  190:     cpu_x86_load_seg_cache(env, R_ES, seg,
  191:                            (seg << 4), 0xffff, 0);
  192:     cpu_x86_load_seg_cache(env, R_FS, seg,
  193:                            (seg << 4), 0xffff, 0);
  194:     cpu_x86_load_seg_cache(env, R_GS, seg,
  195:                            (seg << 4), 0xffff, 0);
  196: 
  197:     /* exception support */
  198:     env->idt.base = (unsigned long)idt_table;
  199:     env->idt.limit = sizeof(idt_table) - 1;
  200:     set_idt(0, 0);
  201:     set_idt(1, 0);
  202:     set_idt(2, 0);
  203:     set_idt(3, 3);
  204:     set_idt(4, 3);
  205:     set_idt(5, 3);
  206:     set_idt(6, 0);
  207:     set_idt(7, 0);
  208:     set_idt(8, 0);
  209:     set_idt(9, 0);
  210:     set_idt(10, 0);
  211:     set_idt(11, 0);
  212:     set_idt(12, 0);
  213:     set_idt(13, 0);
  214:     set_idt(14, 0);
  215:     set_idt(15, 0);
  216:     set_idt(16, 0);
  217:     set_idt(17, 0);
  218:     set_idt(18, 0);
  219:     set_idt(19, 0);
  220: 
  221:     /* put return code */
  222:     *seg_to_linear(env->segs[R_CS].selector, 0) = 0xb4; /* mov ah, $0 */
  223:     *seg_to_linear(env->segs[R_CS].selector, 1) = 0x00;
  224:     *seg_to_linear(env->segs[R_CS].selector, 2) = 0xcd; /* int $0x21 */
  225:     *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
  226:     pushw(env, 0x0000);
  227: 
  228:     /* the value of these registers seem to be assumed by pi_10.com */
  229:     env->regs[R_ESI] = 0x100;
  230:     env->regs[R_ECX] = 0xff;
  231:     env->regs[R_EBP] = 0x0900;
  232:     env->regs[R_EDI] = 0xfffe;
  233: 
  234:     /* inform the emulator of the mmaped memory */
  235:     page_set_flags(0x00000000, 0x110000,
  236:                    PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
  237: 
  238:     for(;;) {
  239:         ret = cpu_x86_exec(env);
  240:         switch(ret) {
  241:         case EXCP0D_GPF:
  242:             {
  243:                 int int_num, ah;
  244:                 int_num = *(uint8_t *)(env->segs[R_CS].base + env->eip + 1);
  245:                 if (int_num != 0x21)
  246:                     goto unknown_int;
  247:                 ah = (env->regs[R_EAX] >> 8) & 0xff;
  248:                 switch(ah) {
  249:                 case 0x00: /* exit */
  250:                     exit(0);
  251:                 case 0x02: /* write char */
  252:                     {
  253:                         uint8_t c = env->regs[R_EDX];
  254:                         write(1, &c, 1);
  255:                     }
  256:                     break;
  257:                 case 0x09: /* write string */
  258:                     {
  259:                         uint8_t c;
  260:                         for(;;) {
  261:                             c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
  262:                             if (c == '$')
  263:                                 break;
  264:                             write(1, &c, 1);
  265:                         }
  266:                         env->regs[R_EAX] = (env->regs[R_EAX] & ~0xff) | '$';
  267:                     }
  268:                     break;
  269:                 default:
  270:                 unknown_int:
  271:                     fprintf(stderr, "unsupported int 0x%02x\n", int_num);
  272:                     cpu_dump_state(env, stderr, fprintf, 0);
  273:                     //                    exit(1);
  274:                 }
  275:                 env->eip += 2;
  276:             }
  277:             break;
  278:         default:
  279:             fprintf(stderr, "unhandled cpu_exec return code (0x%x)\n", ret);
  280:             cpu_dump_state(env, stderr, fprintf, 0);
  281:             exit(1);
  282:         }
  283:     }
  284: }

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