gdbstub.c

   1 /*
   2  * gdb server stub
   3  *
   4  * Copyright (c) 2003-2005 Fabrice Bellard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #ifdef CONFIG_USER_ONLY
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <stdarg.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <unistd.h>
  27
  28 #include "qemu.h"
  29 #else
  30 #include "vl.h"
  31 #endif
  32
  33 #include <sys/socket.h>
  34 #include <netinet/in.h>
  35 #include <netinet/tcp.h>
  36 #include <signal.h>
  37
  38 //#define DEBUG_GDB
  39
  40 enum RSState {
  41     RS_IDLE,
  42     RS_GETLINE,
  43     RS_CHKSUM1,
  44     RS_CHKSUM2,
  45 };
  46 /* XXX: This is not thread safe.  Do we care?  */
  47 static int gdbserver_fd = -1;
  48
  49 typedef struct GDBState {
  50     CPUState *env; /* current CPU */
  51     enum RSState state; /* parsing state */
  52     int fd;
  53     char line_buf[4096];
  54     int line_buf_index;
  55     int line_csum;
  56 #ifdef CONFIG_USER_ONLY
  57     int running_state;
  58 #endif
  59 } GDBState;
  60
  61 #ifdef CONFIG_USER_ONLY
  62 /* XXX: remove this hack.  */
  63 static GDBState gdbserver_state;
  64 #endif
  65
  66 static int get_char(GDBState *s)
  67 {
  68     uint8_t ch;
  69     int ret;
  70
  71     for(;;) {
  72         ret = read(s->fd, &ch, 1);
  73         if (ret < 0) {
  74             if (errno != EINTR && errno != EAGAIN)
  75                 return -1;
  76         } else if (ret == 0) {
  77             return -1;
  78         } else {
  79             break;
  80         }
  81     }
  82     return ch;
  83 }
  84
  85 static void put_buffer(GDBState *s, const uint8_t *buf, int len)
  86 {
  87     int ret;
  88
  89     while (len > 0) {
  90         ret = write(s->fd, buf, len);
  91         if (ret < 0) {
  92             if (errno != EINTR && errno != EAGAIN)
  93                 return;
  94         } else {
  95             buf += ret;
  96             len -= ret;
  97         }
  98     }
  99 }
 100
 101 static inline int fromhex(int v)
 102 {
 103     if (v >= '0' && v <= '9')
 104         return v - '0';
 105     else if (v >= 'A' && v <= 'F')
 106         return v - 'A' + 10;
 107     else if (v >= 'a' && v <= 'f')
 108         return v - 'a' + 10;
 109     else
 110         return 0;
 111 }
 112
 113 static inline int tohex(int v)
 114 {
 115     if (v < 10)
 116         return v + '0';
 117     else
 118         return v - 10 + 'a';
 119 }
 120
 121 static void memtohex(char *buf, const uint8_t *mem, int len)
 122 {
 123     int i, c;
 124     char *q;
 125     q = buf;
 126     for(i = 0; i < len; i++) {
 127         c = mem[i];
 128         *q++ = tohex(c >> 4);
 129         *q++ = tohex(c & 0xf);
 130     }
 131     *q = '\0';
 132 }
 133
 134 static void hextomem(uint8_t *mem, const char *buf, int len)
 135 {
 136     int i;
 137
 138     for(i = 0; i < len; i++) {
 139         mem[i] = (fromhex(buf[0]) << 4) | fromhex(buf[1]);
 140         buf += 2;
 141     }
 142 }
 143
 144 /* return -1 if error, 0 if OK */
 145 static int put_packet(GDBState *s, char *buf)
 146 {
 147     char buf1[3];
 148     int len, csum, ch, i;
 149
 150 #ifdef DEBUG_GDB
 151     printf("reply='%s'\n", buf);
 152 #endif
 153
 154     for(;;) {
 155         buf1[0] = '$';
 156         put_buffer(s, buf1, 1);
 157         len = strlen(buf);
 158         put_buffer(s, buf, len);
 159         csum = 0;
 160         for(i = 0; i < len; i++) {
 161             csum += buf[i];
 162         }
 163         buf1[0] = '#';
 164         buf1[1] = tohex((csum >> 4) & 0xf);
 165         buf1[2] = tohex((csum) & 0xf);
 166
 167         put_buffer(s, buf1, 3);
 168
 169         ch = get_char(s);
 170         if (ch < 0)
 171             return -1;
 172         if (ch == '+')
 173             break;
 174     }
 175     return 0;
 176 }
 177
 178 #if defined(TARGET_I386)
 179
 180 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 181 {
 182     uint32_t *registers = (uint32_t *)mem_buf;
 183     int i, fpus;
 184
 185     for(i = 0; i < 8; i++) {
 186         registers[i] = env->regs[i];
 187     }
 188     registers[8] = env->eip;
 189     registers[9] = env->eflags;
 190     registers[10] = env->segs[R_CS].selector;
 191     registers[11] = env->segs[R_SS].selector;
 192     registers[12] = env->segs[R_DS].selector;
 193     registers[13] = env->segs[R_ES].selector;
 194     registers[14] = env->segs[R_FS].selector;
 195     registers[15] = env->segs[R_GS].selector;
 196     /* XXX: convert floats */
 197     for(i = 0; i < 8; i++) {
 198         memcpy(mem_buf + 16 * 4 + i * 10, &env->fpregs[i], 10);
 199     }
 200     registers[36] = env->fpuc;
 201     fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;
 202     registers[37] = fpus;
 203     registers[38] = 0; /* XXX: convert tags */
 204     registers[39] = 0; /* fiseg */
 205     registers[40] = 0; /* fioff */
 206     registers[41] = 0; /* foseg */
 207     registers[42] = 0; /* fooff */
 208     registers[43] = 0; /* fop */
 209
 210     for(i = 0; i < 16; i++)
 211         tswapls(&registers[i]);
 212     for(i = 36; i < 44; i++)
 213         tswapls(&registers[i]);
 214     return 44 * 4;
 215 }
 216
 217 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 218 {
 219     uint32_t *registers = (uint32_t *)mem_buf;
 220     int i;
 221
 222     for(i = 0; i < 8; i++) {
 223         env->regs[i] = tswapl(registers[i]);
 224     }
 225     env->eip = tswapl(registers[8]);
 226     env->eflags = tswapl(registers[9]);
 227 #if defined(CONFIG_USER_ONLY)
 228 #define LOAD_SEG(index, sreg)\
 229             if (tswapl(registers[index]) != env->segs[sreg].selector)\
 230                 cpu_x86_load_seg(env, sreg, tswapl(registers[index]));
 231             LOAD_SEG(10, R_CS);
 232             LOAD_SEG(11, R_SS);
 233             LOAD_SEG(12, R_DS);
 234             LOAD_SEG(13, R_ES);
 235             LOAD_SEG(14, R_FS);
 236             LOAD_SEG(15, R_GS);
 237 #endif
 238 }
 239
 240 #elif defined (TARGET_PPC)
 241 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 242 {
 243     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 244     int i;
 245
 246     /* fill in gprs */
 247     for(i = 0; i < 32; i++) {
 248         registers[i] = tswapl(env->gpr[i]);
 249     }
 250     /* fill in fprs */
 251     for (i = 0; i < 32; i++) {
 252         registers[(i * 2) + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 253         registers[(i * 2) + 33] = tswapl(*((uint32_t *)&env->fpr[i] + 1));
 254     }
 255     /* nip, msr, ccr, lnk, ctr, xer, mq */
 256     registers[96] = tswapl(env->nip);
 257     registers[97] = tswapl(do_load_msr(env));
 258     tmp = 0;
 259     for (i = 0; i < 8; i++)
 260         tmp |= env->crf[i] << (32 - ((i + 1) * 4));
 261     registers[98] = tswapl(tmp);
 262     registers[99] = tswapl(env->lr);
 263     registers[100] = tswapl(env->ctr);
 264     registers[101] = tswapl(do_load_xer(env));
 265     registers[102] = 0;
 266
 267     return 103 * 4;
 268 }
 269
 270 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 271 {
 272     uint32_t *registers = (uint32_t *)mem_buf;
 273     int i;
 274
 275     /* fill in gprs */
 276     for (i = 0; i < 32; i++) {
 277         env->gpr[i] = tswapl(registers[i]);
 278     }
 279     /* fill in fprs */
 280     for (i = 0; i < 32; i++) {
 281         *((uint32_t *)&env->fpr[i]) = tswapl(registers[(i * 2) + 32]);
 282         *((uint32_t *)&env->fpr[i] + 1) = tswapl(registers[(i * 2) + 33]);
 283     }
 284     /* nip, msr, ccr, lnk, ctr, xer, mq */
 285     env->nip = tswapl(registers[96]);
 286     do_store_msr(env, tswapl(registers[97]));
 287     registers[98] = tswapl(registers[98]);
 288     for (i = 0; i < 8; i++)
 289         env->crf[i] = (registers[98] >> (32 - ((i + 1) * 4))) & 0xF;
 290     env->lr = tswapl(registers[99]);
 291     env->ctr = tswapl(registers[100]);
 292     do_store_xer(env, tswapl(registers[101]));
 293 }
 294 #elif defined (TARGET_SPARC)
 295 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 296 {
 297     target_ulong *registers = (target_ulong *)mem_buf;
 298     int i;
 299
 300     /* fill in g0..g7 */
 301     for(i = 0; i < 8; i++) {
 302         registers[i] = tswapl(env->gregs[i]);
 303     }
 304     /* fill in register window */
 305     for(i = 0; i < 24; i++) {
 306         registers[i + 8] = tswapl(env->regwptr[i]);
 307     }
 308     /* fill in fprs */
 309     for (i = 0; i < 32; i++) {
 310         registers[i + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 311     }
 312 #ifndef TARGET_SPARC64
 313     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 314     registers[64] = tswapl(env->y);
 315     {
 316         target_ulong tmp;
 317
 318         tmp = GET_PSR(env);
 319         registers[65] = tswapl(tmp);
 320     }
 321     registers[66] = tswapl(env->wim);
 322     registers[67] = tswapl(env->tbr);
 323     registers[68] = tswapl(env->pc);
 324     registers[69] = tswapl(env->npc);
 325     registers[70] = tswapl(env->fsr);
 326     registers[71] = 0; /* csr */
 327     registers[72] = 0;
 328     return 73 * sizeof(target_ulong);
 329 #else
 330     for (i = 0; i < 32; i += 2) {
 331         registers[i/2 + 64] = tswapl(*((uint64_t *)&env->fpr[i]));
 332     }
 333     registers[81] = tswapl(env->pc);
 334     registers[82] = tswapl(env->npc);
 335     registers[83] = tswapl(env->tstate[env->tl]);
 336     registers[84] = tswapl(env->fsr);
 337     registers[85] = tswapl(env->fprs);
 338     registers[86] = tswapl(env->y);
 339     return 87 * sizeof(target_ulong);
 340 #endif
 341 }
 342
 343 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 344 {
 345     target_ulong *registers = (target_ulong *)mem_buf;
 346     int i;
 347
 348     /* fill in g0..g7 */
 349     for(i = 0; i < 7; i++) {
 350         env->gregs[i] = tswapl(registers[i]);
 351     }
 352     /* fill in register window */
 353     for(i = 0; i < 24; i++) {
 354         env->regwptr[i] = tswapl(registers[i + 8]);
 355     }
 356     /* fill in fprs */
 357     for (i = 0; i < 32; i++) {
 358         *((uint32_t *)&env->fpr[i]) = tswapl(registers[i + 32]);
 359     }
 360 #ifndef TARGET_SPARC64
 361     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 362     env->y = tswapl(registers[64]);
 363     PUT_PSR(env, tswapl(registers[65]));
 364     env->wim = tswapl(registers[66]);
 365     env->tbr = tswapl(registers[67]);
 366     env->pc = tswapl(registers[68]);
 367     env->npc = tswapl(registers[69]);
 368     env->fsr = tswapl(registers[70]);
 369 #else
 370     for (i = 0; i < 32; i += 2) {
 371         uint64_t tmp;
 372         tmp = tswapl(registers[i/2 + 64]) << 32;
 373         tmp |= tswapl(registers[i/2 + 64 + 1]);
 374         *((uint64_t *)&env->fpr[i]) = tmp;
 375     }
 376     env->pc = tswapl(registers[81]);
 377     env->npc = tswapl(registers[82]);
 378     env->tstate[env->tl] = tswapl(registers[83]);
 379     env->fsr = tswapl(registers[84]);
 380     env->fprs = tswapl(registers[85]);
 381     env->y = tswapl(registers[86]);
 382 #endif
 383 }
 384 #elif defined (TARGET_ARM)
 385 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 386 {
 387     int i;
 388     uint8_t *ptr;
 389
 390     ptr = mem_buf;
 391     /* 16 core integer registers (4 bytes each).  */
 392     for (i = 0; i < 16; i++)
 393       {
 394         *(uint32_t *)ptr = tswapl(env->regs[i]);
 395         ptr += 4;
 396       }
 397     /* 8 FPA registers (12 bytes each), FPS (4 bytes).
 398        Not yet implemented.  */
 399     memset (ptr, 0, 8 * 12 + 4);
 400     ptr += 8 * 12 + 4;
 401     /* CPSR (4 bytes).  */
 402     *(uint32_t *)ptr = tswapl (cpsr_read(env));
 403     ptr += 4;
 404
 405     return ptr - mem_buf;
 406 }
 407
 408 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 409 {
 410     int i;
 411     uint8_t *ptr;
 412
 413     ptr = mem_buf;
 414     /* Core integer registers.  */
 415     for (i = 0; i < 16; i++)
 416       {
 417         env->regs[i] = tswapl(*(uint32_t *)ptr);
 418         ptr += 4;
 419       }
 420     /* Ignore FPA regs and scr.  */
 421     ptr += 8 * 12 + 4;
 422     cpsr_write (env, tswapl(*(uint32_t *)ptr), 0xffffffff);
 423 }
 424 #elif defined (TARGET_MIPS)
 425 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 426 {
 427     int i;
 428     uint8_t *ptr;
 429
 430     ptr = mem_buf;
 431     for (i = 0; i < 32; i++)
 432       {
 433         *(uint32_t *)ptr = tswapl(env->gpr[i]);
 434         ptr += 4;
 435       }
 436
 437     *(uint32_t *)ptr = tswapl(env->CP0_Status);
 438     ptr += 4;
 439
 440     *(uint32_t *)ptr = tswapl(env->LO);
 441     ptr += 4;
 442
 443     *(uint32_t *)ptr = tswapl(env->HI);
 444     ptr += 4;
 445
 446     *(uint32_t *)ptr = tswapl(env->CP0_BadVAddr);
 447     ptr += 4;
 448
 449     *(uint32_t *)ptr = tswapl(env->CP0_Cause);
 450     ptr += 4;
 451
 452     *(uint32_t *)ptr = tswapl(env->PC);
 453     ptr += 4;
 454
 455     /* 32 FP registers, fsr, fir, fp.  Not yet implemented.  */
 456
 457     return ptr - mem_buf;
 458 }
 459
 460 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 461 {
 462     int i;
 463     uint8_t *ptr;
 464
 465     ptr = mem_buf;
 466     for (i = 0; i < 32; i++)
 467       {
 468         env->gpr[i] = tswapl(*(uint32_t *)ptr);
 469         ptr += 4;
 470       }
 471
 472     env->CP0_Status = tswapl(*(uint32_t *)ptr);
 473     ptr += 4;
 474
 475     env->LO = tswapl(*(uint32_t *)ptr);
 476     ptr += 4;
 477
 478     env->HI = tswapl(*(uint32_t *)ptr);
 479     ptr += 4;
 480
 481     env->CP0_BadVAddr = tswapl(*(uint32_t *)ptr);
 482     ptr += 4;
 483
 484     env->CP0_Cause = tswapl(*(uint32_t *)ptr);
 485     ptr += 4;
 486
 487     env->PC = tswapl(*(uint32_t *)ptr);
 488     ptr += 4;
 489 }
 490 #else
 491 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 492 {
 493     return 0;
 494 }
 495
 496 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 497 {
 498 }
 499
 500 #endif
 501
 502 static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
 503 {
 504     const char *p;
 505     int ch, reg_size, type;
 506     char buf[4096];
 507     uint8_t mem_buf[2000];
 508     uint32_t *registers;
 509     uint32_t addr, len;
 510
 511 #ifdef DEBUG_GDB
 512     printf("command='%s'\n", line_buf);
 513 #endif
 514     p = line_buf;
 515     ch = *p++;
 516     switch(ch) {
 517     case '?':
 518         /* TODO: Make this return the correct value for user-mode.  */
 519         snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
 520         put_packet(s, buf);
 521         break;
 522     case 'c':
 523         if (*p != '\0') {
 524             addr = strtoul(p, (char **)&p, 16);
 525 #if defined(TARGET_I386)
 526             env->eip = addr;
 527 #elif defined (TARGET_PPC)
 528             env->nip = addr;
 529 #elif defined (TARGET_SPARC)
 530             env->pc = addr;
 531             env->npc = addr + 4;
 532 #elif defined (TARGET_ARM)
 533             env->regs[15] = addr;
 534 #endif
 535         }
 536 #ifdef CONFIG_USER_ONLY
 537         s->running_state = 1;
 538 #else
 539         vm_start();
 540 #endif
 541         return RS_IDLE;
 542     case 's':
 543         if (*p != '\0') {
 544             addr = strtoul(p, (char **)&p, 16);
 545 #if defined(TARGET_I386)
 546             env->eip = addr;
 547 #elif defined (TARGET_PPC)
 548             env->nip = addr;
 549 #elif defined (TARGET_SPARC)
 550             env->pc = addr;
 551             env->npc = addr + 4;
 552 #elif defined (TARGET_ARM)
 553             env->regs[15] = addr;
 554 #endif
 555         }
 556         cpu_single_step(env, 1);
 557 #ifdef CONFIG_USER_ONLY
 558         s->running_state = 1;
 559 #else
 560         vm_start();
 561 #endif
 562         return RS_IDLE;
 563     case 'g':
 564         reg_size = cpu_gdb_read_registers(env, mem_buf);
 565         memtohex(buf, mem_buf, reg_size);
 566         put_packet(s, buf);
 567         break;
 568     case 'G':
 569         registers = (void *)mem_buf;
 570         len = strlen(p) / 2;
 571         hextomem((uint8_t *)registers, p, len);
 572         cpu_gdb_write_registers(env, mem_buf, len);
 573         put_packet(s, "OK");
 574         break;
 575     case 'm':
 576         addr = strtoul(p, (char **)&p, 16);
 577         if (*p == ',')
 578             p++;
 579         len = strtoul(p, NULL, 16);
 580         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0) {
 581             put_packet (s, "E14");
 582         } else {
 583             memtohex(buf, mem_buf, len);
 584             put_packet(s, buf);
 585         }
 586         break;
 587     case 'M':
 588         addr = strtoul(p, (char **)&p, 16);
 589         if (*p == ',')
 590             p++;
 591         len = strtoul(p, (char **)&p, 16);
 592         if (*p == ':')
 593             p++;
 594         hextomem(mem_buf, p, len);
 595         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
 596             put_packet(s, "E14");
 597         else
 598             put_packet(s, "OK");
 599         break;
 600     case 'Z':
 601         type = strtoul(p, (char **)&p, 16);
 602         if (*p == ',')
 603             p++;
 604         addr = strtoul(p, (char **)&p, 16);
 605         if (*p == ',')
 606             p++;
 607         len = strtoul(p, (char **)&p, 16);
 608         if (type == 0 || type == 1) {
 609             if (cpu_breakpoint_insert(env, addr) < 0)
 610                 goto breakpoint_error;
 611             put_packet(s, "OK");
 612         } else {
 613         breakpoint_error:
 614             put_packet(s, "E22");
 615         }
 616         break;
 617     case 'z':
 618         type = strtoul(p, (char **)&p, 16);
 619         if (*p == ',')
 620             p++;
 621         addr = strtoul(p, (char **)&p, 16);
 622         if (*p == ',')
 623             p++;
 624         len = strtoul(p, (char **)&p, 16);
 625         if (type == 0 || type == 1) {
 626             cpu_breakpoint_remove(env, addr);
 627             put_packet(s, "OK");
 628         } else {
 629             goto breakpoint_error;
 630         }
 631         break;
 632     default:
 633         //        unknown_command:
 634         /* put empty packet */
 635         buf[0] = '\0';
 636         put_packet(s, buf);
 637         break;
 638     }
 639     return RS_IDLE;
 640 }
 641
 642 extern void tb_flush(CPUState *env);
 643
 644 #ifndef CONFIG_USER_ONLY
 645 static void gdb_vm_stopped(void *opaque, int reason)
 646 {
 647     GDBState *s = opaque;
 648     char buf[256];
 649     int ret;
 650
 651     /* disable single step if it was enable */
 652     cpu_single_step(s->env, 0);
 653
 654     if (reason == EXCP_DEBUG) {
 655         tb_flush(s->env);
 656         ret = SIGTRAP;
 657     }
 658     else
 659         ret = 0;
 660     snprintf(buf, sizeof(buf), "S%02x", ret);
 661     put_packet(s, buf);
 662 }
 663 #endif
 664
 665 static void gdb_read_byte(GDBState *s, int ch)
 666 {
 667     CPUState *env = s->env;
 668     int i, csum;
 669     char reply[1];
 670
 671 #ifndef CONFIG_USER_ONLY
 672     if (vm_running) {
 673         /* when the CPU is running, we cannot do anything except stop
 674            it when receiving a char */
 675         vm_stop(EXCP_INTERRUPT);
 676     } else
 677 #endif
 678     {
 679         switch(s->state) {
 680         case RS_IDLE:
 681             if (ch == '$') {
 682                 s->line_buf_index = 0;
 683                 s->state = RS_GETLINE;
 684             }
 685             break;
 686         case RS_GETLINE:
 687             if (ch == '#') {
 688             s->state = RS_CHKSUM1;
 689             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
 690                 s->state = RS_IDLE;
 691             } else {
 692             s->line_buf[s->line_buf_index++] = ch;
 693             }
 694             break;
 695         case RS_CHKSUM1:
 696             s->line_buf[s->line_buf_index] = '\0';
 697             s->line_csum = fromhex(ch) << 4;
 698             s->state = RS_CHKSUM2;
 699             break;
 700         case RS_CHKSUM2:
 701             s->line_csum |= fromhex(ch);
 702             csum = 0;
 703             for(i = 0; i < s->line_buf_index; i++) {
 704                 csum += s->line_buf[i];
 705             }
 706             if (s->line_csum != (csum & 0xff)) {
 707                 reply[0] = '-';
 708                 put_buffer(s, reply, 1);
 709                 s->state = RS_IDLE;
 710             } else {
 711                 reply[0] = '+';
 712                 put_buffer(s, reply, 1);
 713                 s->state = gdb_handle_packet(s, env, s->line_buf);
 714             }
 715             break;
 716         }
 717     }
 718 }
 719
 720 #ifdef CONFIG_USER_ONLY
 721 int
 722 gdb_handlesig (CPUState *env, int sig)
 723 {
 724   GDBState *s;
 725   char buf[256];
 726   int n;
 727
 728   if (gdbserver_fd < 0)
 729     return sig;
 730
 731   s = &gdbserver_state;
 732
 733   /* disable single step if it was enabled */
 734   cpu_single_step(env, 0);
 735   tb_flush(env);
 736
 737   if (sig != 0)
 738     {
 739       snprintf(buf, sizeof(buf), "S%02x", sig);
 740       put_packet(s, buf);
 741     }
 742
 743   sig = 0;
 744   s->state = RS_IDLE;
 745   s->running_state = 0;
 746   while (s->running_state == 0) {
 747       n = read (s->fd, buf, 256);
 748       if (n > 0)
 749         {
 750           int i;
 751
 752           for (i = 0; i < n; i++)
 753             gdb_read_byte (s, buf[i]);
 754         }
 755       else if (n == 0 || errno != EAGAIN)
 756         {
 757           /* XXX: Connection closed.  Should probably wait for annother
 758              connection before continuing.  */
 759           return sig;
 760         }
 761   }
 762   return sig;
 763 }
 764
 765 /* Tell the remote gdb that the process has exited.  */
 766 void gdb_exit(CPUState *env, int code)
 767 {
 768   GDBState *s;
 769   char buf[4];
 770
 771   if (gdbserver_fd < 0)
 772     return;
 773
 774   s = &gdbserver_state;
 775
 776   snprintf(buf, sizeof(buf), "W%02x", code);
 777   put_packet(s, buf);
 778 }
 779
 780 #else
 781 static void gdb_read(void *opaque)
 782 {
 783     GDBState *s = opaque;
 784     int i, size;
 785     uint8_t buf[4096];
 786
 787     size = read(s->fd, buf, sizeof(buf));
 788     if (size < 0)
 789         return;
 790     if (size == 0) {
 791         /* end of connection */
 792         qemu_del_vm_stop_handler(gdb_vm_stopped, s);
 793         qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
 794         qemu_free(s);
 795         vm_start();
 796     } else {
 797         for(i = 0; i < size; i++)
 798             gdb_read_byte(s, buf[i]);
 799     }
 800 }
 801
 802 #endif
 803
 804 static void gdb_accept(void *opaque)
 805 {
 806     GDBState *s;
 807     struct sockaddr_in sockaddr;
 808     socklen_t len;
 809     int val, fd;
 810
 811     for(;;) {
 812         len = sizeof(sockaddr);
 813         fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
 814         if (fd < 0 && errno != EINTR) {
 815             perror("accept");
 816             return;
 817         } else if (fd >= 0) {
 818             break;
 819         }
 820     }
 821
 822     /* set short latency */
 823     val = 1;
 824     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
 825
 826 #ifdef CONFIG_USER_ONLY
 827     s = &gdbserver_state;
 828     memset (s, 0, sizeof (GDBState));
 829 #else
 830     s = qemu_mallocz(sizeof(GDBState));
 831     if (!s) {
 832         close(fd);
 833         return;
 834     }
 835 #endif
 836     s->env = first_cpu; /* XXX: allow to change CPU */
 837     s->fd = fd;
 838
 839     fcntl(fd, F_SETFL, O_NONBLOCK);
 840
 841 #ifndef CONFIG_USER_ONLY
 842     /* stop the VM */
 843     vm_stop(EXCP_INTERRUPT);
 844
 845     /* start handling I/O */
 846     qemu_set_fd_handler(s->fd, gdb_read, NULL, s);
 847     /* when the VM is stopped, the following callback is called */
 848     qemu_add_vm_stop_handler(gdb_vm_stopped, s);
 849 #endif
 850 }
 851
 852 static int gdbserver_open(int port)
 853 {
 854     struct sockaddr_in sockaddr;
 855     int fd, val, ret;
 856
 857     fd = socket(PF_INET, SOCK_STREAM, 0);
 858     if (fd < 0) {
 859         perror("socket");
 860         return -1;
 861     }
 862
 863     /* allow fast reuse */
 864     val = 1;
 865     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 866
 867     sockaddr.sin_family = AF_INET;
 868     sockaddr.sin_port = htons(port);
 869     sockaddr.sin_addr.s_addr = 0;
 870     ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 871     if (ret < 0) {
 872         perror("bind");
 873         return -1;
 874     }
 875     ret = listen(fd, 0);
 876     if (ret < 0) {
 877         perror("listen");
 878         return -1;
 879     }
 880 #ifndef CONFIG_USER_ONLY
 881     fcntl(fd, F_SETFL, O_NONBLOCK);
 882 #endif
 883     return fd;
 884 }
 885
 886 int gdbserver_start(int port)
 887 {
 888     gdbserver_fd = gdbserver_open(port);
 889     if (gdbserver_fd < 0)
 890         return -1;
 891     /* accept connections */
 892 #ifdef CONFIG_USER_ONLY
 893     gdb_accept (NULL);
 894 #else
 895     qemu_set_fd_handler(gdbserver_fd, gdb_accept, NULL, NULL);
 896 #endif
 897     return 0;
 898 }