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 #else
 425 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 426 {
 427     return 0;
 428 }
 429
 430 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 431 {
 432 }
 433
 434 #endif
 435
 436 static int gdb_handle_packet(GDBState *s, CPUState *env, const char *line_buf)
 437 {
 438     const char *p;
 439     int ch, reg_size, type;
 440     char buf[4096];
 441     uint8_t mem_buf[2000];
 442     uint32_t *registers;
 443     uint32_t addr, len;
 444
 445 #ifdef DEBUG_GDB
 446     printf("command='%s'\n", line_buf);
 447 #endif
 448     p = line_buf;
 449     ch = *p++;
 450     switch(ch) {
 451     case '?':
 452         /* TODO: Make this return the correct value for user-mode.  */
 453         snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
 454         put_packet(s, buf);
 455         break;
 456     case 'c':
 457         if (*p != '\0') {
 458             addr = strtoul(p, (char **)&p, 16);
 459 #if defined(TARGET_I386)
 460             env->eip = addr;
 461 #elif defined (TARGET_PPC)
 462             env->nip = addr;
 463 #elif defined (TARGET_SPARC)
 464             env->pc = addr;
 465             env->npc = addr + 4;
 466 #elif defined (TARGET_ARM)
 467             env->regs[15] = addr;
 468 #endif
 469         }
 470 #ifdef CONFIG_USER_ONLY
 471         s->running_state = 1;
 472 #else
 473         vm_start();
 474 #endif
 475         return RS_IDLE;
 476     case 's':
 477         if (*p != '\0') {
 478             addr = strtoul(p, (char **)&p, 16);
 479 #if defined(TARGET_I386)
 480             env->eip = addr;
 481 #elif defined (TARGET_PPC)
 482             env->nip = addr;
 483 #elif defined (TARGET_SPARC)
 484             env->pc = addr;
 485             env->npc = addr + 4;
 486 #elif defined (TARGET_ARM)
 487             env->regs[15] = addr;
 488 #endif
 489         }
 490         cpu_single_step(env, 1);
 491 #ifdef CONFIG_USER_ONLY
 492         s->running_state = 1;
 493 #else
 494         vm_start();
 495 #endif
 496         return RS_IDLE;
 497     case 'g':
 498         reg_size = cpu_gdb_read_registers(env, mem_buf);
 499         memtohex(buf, mem_buf, reg_size);
 500         put_packet(s, buf);
 501         break;
 502     case 'G':
 503         registers = (void *)mem_buf;
 504         len = strlen(p) / 2;
 505         hextomem((uint8_t *)registers, p, len);
 506         cpu_gdb_write_registers(env, mem_buf, len);
 507         put_packet(s, "OK");
 508         break;
 509     case 'm':
 510         addr = strtoul(p, (char **)&p, 16);
 511         if (*p == ',')
 512             p++;
 513         len = strtoul(p, NULL, 16);
 514         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0)
 515             memset(mem_buf, 0, len);
 516         memtohex(buf, mem_buf, len);
 517         put_packet(s, buf);
 518         break;
 519     case 'M':
 520         addr = strtoul(p, (char **)&p, 16);
 521         if (*p == ',')
 522             p++;
 523         len = strtoul(p, (char **)&p, 16);
 524         if (*p == ':')
 525             p++;
 526         hextomem(mem_buf, p, len);
 527         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
 528             put_packet(s, "E14");
 529         else
 530             put_packet(s, "OK");
 531         break;
 532     case 'Z':
 533         type = strtoul(p, (char **)&p, 16);
 534         if (*p == ',')
 535             p++;
 536         addr = strtoul(p, (char **)&p, 16);
 537         if (*p == ',')
 538             p++;
 539         len = strtoul(p, (char **)&p, 16);
 540         if (type == 0 || type == 1) {
 541             if (cpu_breakpoint_insert(env, addr) < 0)
 542                 goto breakpoint_error;
 543             put_packet(s, "OK");
 544         } else {
 545         breakpoint_error:
 546             put_packet(s, "E22");
 547         }
 548         break;
 549     case 'z':
 550         type = strtoul(p, (char **)&p, 16);
 551         if (*p == ',')
 552             p++;
 553         addr = strtoul(p, (char **)&p, 16);
 554         if (*p == ',')
 555             p++;
 556         len = strtoul(p, (char **)&p, 16);
 557         if (type == 0 || type == 1) {
 558             cpu_breakpoint_remove(env, addr);
 559             put_packet(s, "OK");
 560         } else {
 561             goto breakpoint_error;
 562         }
 563         break;
 564     default:
 565         //        unknown_command:
 566         /* put empty packet */
 567         buf[0] = '\0';
 568         put_packet(s, buf);
 569         break;
 570     }
 571     return RS_IDLE;
 572 }
 573
 574 extern void tb_flush(CPUState *env);
 575
 576 #ifndef CONFIG_USER_ONLY
 577 static void gdb_vm_stopped(void *opaque, int reason)
 578 {
 579     GDBState *s = opaque;
 580     char buf[256];
 581     int ret;
 582
 583     /* disable single step if it was enable */
 584     cpu_single_step(s->env, 0);
 585
 586     if (reason == EXCP_DEBUG) {
 587         tb_flush(s->env);
 588         ret = SIGTRAP;
 589     }
 590     else
 591         ret = 0;
 592     snprintf(buf, sizeof(buf), "S%02x", ret);
 593     put_packet(s, buf);
 594 }
 595 #endif
 596
 597 static void gdb_read_byte(GDBState *s, int ch)
 598 {
 599     CPUState *env = s->env;
 600     int i, csum;
 601     char reply[1];
 602
 603 #ifndef CONFIG_USER_ONLY
 604     if (vm_running) {
 605         /* when the CPU is running, we cannot do anything except stop
 606            it when receiving a char */
 607         vm_stop(EXCP_INTERRUPT);
 608     } else
 609 #endif
 610     {
 611         switch(s->state) {
 612         case RS_IDLE:
 613             if (ch == '$') {
 614                 s->line_buf_index = 0;
 615                 s->state = RS_GETLINE;
 616             }
 617             break;
 618         case RS_GETLINE:
 619             if (ch == '#') {
 620             s->state = RS_CHKSUM1;
 621             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
 622                 s->state = RS_IDLE;
 623             } else {
 624             s->line_buf[s->line_buf_index++] = ch;
 625             }
 626             break;
 627         case RS_CHKSUM1:
 628             s->line_buf[s->line_buf_index] = '\0';
 629             s->line_csum = fromhex(ch) << 4;
 630             s->state = RS_CHKSUM2;
 631             break;
 632         case RS_CHKSUM2:
 633             s->line_csum |= fromhex(ch);
 634             csum = 0;
 635             for(i = 0; i < s->line_buf_index; i++) {
 636                 csum += s->line_buf[i];
 637             }
 638             if (s->line_csum != (csum & 0xff)) {
 639                 reply[0] = '-';
 640                 put_buffer(s, reply, 1);
 641                 s->state = RS_IDLE;
 642             } else {
 643                 reply[0] = '+';
 644                 put_buffer(s, reply, 1);
 645                 s->state = gdb_handle_packet(s, env, s->line_buf);
 646             }
 647             break;
 648         }
 649     }
 650 }
 651
 652 #ifdef CONFIG_USER_ONLY
 653 int
 654 gdb_handlesig (CPUState *env, int sig)
 655 {
 656   GDBState *s;
 657   char buf[256];
 658   int n;
 659
 660   if (gdbserver_fd < 0)
 661     return sig;
 662
 663   s = &gdbserver_state;
 664
 665   /* disable single step if it was enabled */
 666   cpu_single_step(env, 0);
 667   tb_flush(env);
 668
 669   if (sig != 0)
 670     {
 671       snprintf(buf, sizeof(buf), "S%02x", sig);
 672       put_packet(s, buf);
 673     }
 674
 675   sig = 0;
 676   s->state = RS_IDLE;
 677   s->running_state = 0;
 678   while (s->running_state == 0) {
 679       n = read (s->fd, buf, 256);
 680       if (n > 0)
 681         {
 682           int i;
 683
 684           for (i = 0; i < n; i++)
 685             gdb_read_byte (s, buf[i]);
 686         }
 687       else if (n == 0 || errno != EAGAIN)
 688         {
 689           /* XXX: Connection closed.  Should probably wait for annother
 690              connection before continuing.  */
 691           return sig;
 692         }
 693   }
 694   return sig;
 695 }
 696
 697 /* Tell the remote gdb that the process has exited.  */
 698 void gdb_exit(CPUState *env, int code)
 699 {
 700   GDBState *s;
 701   char buf[4];
 702
 703   if (gdbserver_fd < 0)
 704     return;
 705
 706   s = &gdbserver_state;
 707
 708   snprintf(buf, sizeof(buf), "W%02x", code);
 709   put_packet(s, buf);
 710 }
 711
 712 #else
 713 static void gdb_read(void *opaque)
 714 {
 715     GDBState *s = opaque;
 716     int i, size;
 717     uint8_t buf[4096];
 718
 719     size = read(s->fd, buf, sizeof(buf));
 720     if (size < 0)
 721         return;
 722     if (size == 0) {
 723         /* end of connection */
 724         qemu_del_vm_stop_handler(gdb_vm_stopped, s);
 725         qemu_set_fd_handler(s->fd, NULL, NULL, NULL);
 726         qemu_free(s);
 727         vm_start();
 728     } else {
 729         for(i = 0; i < size; i++)
 730             gdb_read_byte(s, buf[i]);
 731     }
 732 }
 733
 734 #endif
 735
 736 static void gdb_accept(void *opaque)
 737 {
 738     GDBState *s;
 739     struct sockaddr_in sockaddr;
 740     socklen_t len;
 741     int val, fd;
 742
 743     for(;;) {
 744         len = sizeof(sockaddr);
 745         fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
 746         if (fd < 0 && errno != EINTR) {
 747             perror("accept");
 748             return;
 749         } else if (fd >= 0) {
 750             break;
 751         }
 752     }
 753
 754     /* set short latency */
 755     val = 1;
 756     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
 757
 758 #ifdef CONFIG_USER_ONLY
 759     s = &gdbserver_state;
 760     memset (s, 0, sizeof (GDBState));
 761 #else
 762     s = qemu_mallocz(sizeof(GDBState));
 763     if (!s) {
 764         close(fd);
 765         return;
 766     }
 767 #endif
 768     s->env = first_cpu; /* XXX: allow to change CPU */
 769     s->fd = fd;
 770
 771     fcntl(fd, F_SETFL, O_NONBLOCK);
 772
 773 #ifndef CONFIG_USER_ONLY
 774     /* stop the VM */
 775     vm_stop(EXCP_INTERRUPT);
 776
 777     /* start handling I/O */
 778     qemu_set_fd_handler(s->fd, gdb_read, NULL, s);
 779     /* when the VM is stopped, the following callback is called */
 780     qemu_add_vm_stop_handler(gdb_vm_stopped, s);
 781 #endif
 782 }
 783
 784 static int gdbserver_open(int port)
 785 {
 786     struct sockaddr_in sockaddr;
 787     int fd, val, ret;
 788
 789     fd = socket(PF_INET, SOCK_STREAM, 0);
 790     if (fd < 0) {
 791         perror("socket");
 792         return -1;
 793     }
 794
 795     /* allow fast reuse */
 796     val = 1;
 797     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 798
 799     sockaddr.sin_family = AF_INET;
 800     sockaddr.sin_port = htons(port);
 801     sockaddr.sin_addr.s_addr = 0;
 802     ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 803     if (ret < 0) {
 804         perror("bind");
 805         return -1;
 806     }
 807     ret = listen(fd, 0);
 808     if (ret < 0) {
 809         perror("listen");
 810         return -1;
 811     }
 812 #ifndef CONFIG_USER_ONLY
 813     fcntl(fd, F_SETFL, O_NONBLOCK);
 814 #endif
 815     return fd;
 816 }
 817
 818 int gdbserver_start(int port)
 819 {
 820     gdbserver_fd = gdbserver_open(port);
 821     if (gdbserver_fd < 0)
 822         return -1;
 823     /* accept connections */
 824 #ifdef CONFIG_USER_ONLY
 825     gdb_accept (NULL);
 826 #else
 827     qemu_set_fd_handler(gdbserver_fd, gdb_accept, NULL, NULL);
 828 #endif
 829     return 0;
 830 }