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1.1 root 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>
1.1.1.2 ! root 13: #include <malloc.h>
1.1 root 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:
1.1.1.2 ! root 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:
1.1 root 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,
1.1.1.2 ! root 228: (seg << 4), 0xffff, 0);
1.1 root 229: cpu_x86_load_seg_cache(env, R_SS, seg,
1.1.1.2 ! root 230: (seg << 4), 0xffff, 0);
1.1 root 231: cpu_x86_load_seg_cache(env, R_DS, seg,
1.1.1.2 ! root 232: (seg << 4), 0xffff, 0);
1.1 root 233: cpu_x86_load_seg_cache(env, R_ES, seg,
1.1.1.2 ! root 234: (seg << 4), 0xffff, 0);
1.1 root 235: cpu_x86_load_seg_cache(env, R_FS, seg,
1.1.1.2 ! root 236: (seg << 4), 0xffff, 0);
1.1 root 237: cpu_x86_load_seg_cache(env, R_GS, seg,
1.1.1.2 ! root 238: (seg << 4), 0xffff, 0);
1.1 root 239:
240: /* exception support */
1.1.1.2 ! root 241: env->idt.base = (unsigned long)idt_table;
1.1 root 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 $0x21 */
268: *seg_to_linear(env->segs[R_CS].selector, 3) = 0x21;
269: pushw(env, 0x0000);
270:
271: /* the value of these registers seem to be assumed by pi_10.com */
272: env->regs[R_ESI] = 0x100;
273: env->regs[R_ECX] = 0xff;
274: env->regs[R_EBP] = 0x0900;
275: env->regs[R_EDI] = 0xfffe;
276:
277: /* inform the emulator of the mmaped memory */
278: page_set_flags(0x00000000, 0x110000,
279: PAGE_WRITE | PAGE_READ | PAGE_EXEC | PAGE_VALID);
280:
281: for(;;) {
282: ret = cpu_x86_exec(env);
283: switch(ret) {
284: case EXCP0D_GPF:
285: {
286: int int_num, ah;
1.1.1.2 ! root 287: int_num = *(uint8_t *)(env->segs[R_CS].base + env->eip + 1);
1.1 root 288: if (int_num != 0x21)
289: goto unknown_int;
290: ah = (env->regs[R_EAX] >> 8) & 0xff;
291: switch(ah) {
292: case 0x00: /* exit */
293: exit(0);
294: case 0x02: /* write char */
295: {
296: uint8_t c = env->regs[R_EDX];
297: write(1, &c, 1);
298: }
299: break;
300: case 0x09: /* write string */
301: {
302: uint8_t c;
303: for(;;) {
304: c = *seg_to_linear(env->segs[R_DS].selector, env->regs[R_EAX]);
305: if (c == '$')
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);
1.1.1.2 ! root 315: cpu_dump_state(env, stderr, fprintf, 0);
1.1 root 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);
1.1.1.2 ! root 323: cpu_dump_state(env, stderr, fprintf, 0);
1.1 root 324: exit(1);
325: }
326: }
327: }
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