gdbstub.c

   1 /*
   2  * gdb server stub
   3  *
   4  * Copyright (c) 2003 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 #include "vl.h"
  21
  22 #include <sys/socket.h>
  23 #include <netinet/in.h>
  24 #include <netinet/tcp.h>
  25 #include <signal.h>
  26
  27 //#define DEBUG_GDB
  28
  29 enum RSState {
  30     RS_IDLE,
  31     RS_GETLINE,
  32     RS_CHKSUM1,
  33     RS_CHKSUM2,
  34 };
  35
  36 static int gdbserver_fd;
  37
  38 typedef struct GDBState {
  39     enum RSState state;
  40     int fd;
  41     char line_buf[4096];
  42     int line_buf_index;
  43     int line_csum;
  44 } GDBState;
  45
  46 static int get_char(GDBState *s)
  47 {
  48     uint8_t ch;
  49     int ret;
  50
  51     for(;;) {
  52         ret = read(s->fd, &ch, 1);
  53         if (ret < 0) {
  54             if (errno != EINTR && errno != EAGAIN)
  55                 return -1;
  56         } else if (ret == 0) {
  57             return -1;
  58         } else {
  59             break;
  60         }
  61     }
  62     return ch;
  63 }
  64
  65 static void put_buffer(GDBState *s, const uint8_t *buf, int len)
  66 {
  67     int ret;
  68
  69     while (len > 0) {
  70         ret = write(s->fd, buf, len);
  71         if (ret < 0) {
  72             if (errno != EINTR && errno != EAGAIN)
  73                 return;
  74         } else {
  75             buf += ret;
  76             len -= ret;
  77         }
  78     }
  79 }
  80
  81 static inline int fromhex(int v)
  82 {
  83     if (v >= '0' && v <= '9')
  84         return v - '0';
  85     else if (v >= 'A' && v <= 'F')
  86         return v - 'A' + 10;
  87     else if (v >= 'a' && v <= 'f')
  88         return v - 'a' + 10;
  89     else
  90         return 0;
  91 }
  92
  93 static inline int tohex(int v)
  94 {
  95     if (v < 10)
  96         return v + '0';
  97     else
  98         return v - 10 + 'a';
  99 }
 100
 101 static void memtohex(char *buf, const uint8_t *mem, int len)
 102 {
 103     int i, c;
 104     char *q;
 105     q = buf;
 106     for(i = 0; i < len; i++) {
 107         c = mem[i];
 108         *q++ = tohex(c >> 4);
 109         *q++ = tohex(c & 0xf);
 110     }
 111     *q = '\0';
 112 }
 113
 114 static void hextomem(uint8_t *mem, const char *buf, int len)
 115 {
 116     int i;
 117
 118     for(i = 0; i < len; i++) {
 119         mem[i] = (fromhex(buf[0]) << 4) | fromhex(buf[1]);
 120         buf += 2;
 121     }
 122 }
 123
 124 /* return -1 if error, 0 if OK */
 125 static int put_packet(GDBState *s, char *buf)
 126 {
 127     char buf1[3];
 128     int len, csum, ch, i;
 129
 130 #ifdef DEBUG_GDB
 131     printf("reply='%s'\n", buf);
 132 #endif
 133
 134     for(;;) {
 135         buf1[0] = '$';
 136         put_buffer(s, buf1, 1);
 137         len = strlen(buf);
 138         put_buffer(s, buf, len);
 139         csum = 0;
 140         for(i = 0; i < len; i++) {
 141             csum += buf[i];
 142         }
 143         buf1[0] = '#';
 144         buf1[1] = tohex((csum >> 4) & 0xf);
 145         buf1[2] = tohex((csum) & 0xf);
 146
 147         put_buffer(s, buf1, 3);
 148
 149         ch = get_char(s);
 150         if (ch < 0)
 151             return -1;
 152         if (ch == '+')
 153             break;
 154     }
 155     return 0;
 156 }
 157
 158 #if defined(TARGET_I386)
 159
 160 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 161 {
 162     uint32_t *registers = (uint32_t *)mem_buf;
 163     int i, fpus;
 164
 165     for(i = 0; i < 8; i++) {
 166         registers[i] = env->regs[i];
 167     }
 168     registers[8] = env->eip;
 169     registers[9] = env->eflags;
 170     registers[10] = env->segs[R_CS].selector;
 171     registers[11] = env->segs[R_SS].selector;
 172     registers[12] = env->segs[R_DS].selector;
 173     registers[13] = env->segs[R_ES].selector;
 174     registers[14] = env->segs[R_FS].selector;
 175     registers[15] = env->segs[R_GS].selector;
 176     /* XXX: convert floats */
 177     for(i = 0; i < 8; i++) {
 178         memcpy(mem_buf + 16 * 4 + i * 10, &env->fpregs[i], 10);
 179     }
 180     registers[36] = env->fpuc;
 181     fpus = (env->fpus & ~0x3800) | (env->fpstt & 0x7) << 11;
 182     registers[37] = fpus;
 183     registers[38] = 0; /* XXX: convert tags */
 184     registers[39] = 0; /* fiseg */
 185     registers[40] = 0; /* fioff */
 186     registers[41] = 0; /* foseg */
 187     registers[42] = 0; /* fooff */
 188     registers[43] = 0; /* fop */
 189
 190     for(i = 0; i < 16; i++)
 191         tswapls(&registers[i]);
 192     for(i = 36; i < 44; i++)
 193         tswapls(&registers[i]);
 194     return 44 * 4;
 195 }
 196
 197 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 198 {
 199     uint32_t *registers = (uint32_t *)mem_buf;
 200     int i;
 201
 202     for(i = 0; i < 8; i++) {
 203         env->regs[i] = tswapl(registers[i]);
 204     }
 205     env->eip = tswapl(registers[8]);
 206     env->eflags = tswapl(registers[9]);
 207 #if defined(CONFIG_USER_ONLY)
 208 #define LOAD_SEG(index, sreg)\
 209             if (tswapl(registers[index]) != env->segs[sreg].selector)\
 210                 cpu_x86_load_seg(env, sreg, tswapl(registers[index]));
 211             LOAD_SEG(10, R_CS);
 212             LOAD_SEG(11, R_SS);
 213             LOAD_SEG(12, R_DS);
 214             LOAD_SEG(13, R_ES);
 215             LOAD_SEG(14, R_FS);
 216             LOAD_SEG(15, R_GS);
 217 #endif
 218 }
 219
 220 #elif defined (TARGET_PPC)
 221 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 222 {
 223     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 224     int i;
 225
 226     /* fill in gprs */
 227     for(i = 0; i < 32; i++) {
 228         registers[i] = tswapl(env->gpr[i]);
 229     }
 230     /* fill in fprs */
 231     for (i = 0; i < 32; i++) {
 232         registers[(i * 2) + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 233         registers[(i * 2) + 33] = tswapl(*((uint32_t *)&env->fpr[i] + 1));
 234     }
 235     /* nip, msr, ccr, lnk, ctr, xer, mq */
 236     registers[96] = tswapl(env->nip);
 237     registers[97] = tswapl(_load_msr(env));
 238     tmp = 0;
 239     for (i = 0; i < 8; i++)
 240         tmp |= env->crf[i] << (32 - ((i + 1) * 4));
 241     registers[98] = tswapl(tmp);
 242     registers[99] = tswapl(env->lr);
 243     registers[100] = tswapl(env->ctr);
 244     registers[101] = tswapl(_load_xer(env));
 245     registers[102] = 0;
 246
 247     return 103 * 4;
 248 }
 249
 250 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 251 {
 252     uint32_t *registers = (uint32_t *)mem_buf;
 253     int i;
 254
 255     /* fill in gprs */
 256     for (i = 0; i < 32; i++) {
 257         env->gpr[i] = tswapl(registers[i]);
 258     }
 259     /* fill in fprs */
 260     for (i = 0; i < 32; i++) {
 261         *((uint32_t *)&env->fpr[i]) = tswapl(registers[(i * 2) + 32]);
 262         *((uint32_t *)&env->fpr[i] + 1) = tswapl(registers[(i * 2) + 33]);
 263     }
 264     /* nip, msr, ccr, lnk, ctr, xer, mq */
 265     env->nip = tswapl(registers[96]);
 266     _store_msr(env, tswapl(registers[97]));
 267     registers[98] = tswapl(registers[98]);
 268     for (i = 0; i < 8; i++)
 269         env->crf[i] = (registers[98] >> (32 - ((i + 1) * 4))) & 0xF;
 270     env->lr = tswapl(registers[99]);
 271     env->ctr = tswapl(registers[100]);
 272     _store_xer(env, tswapl(registers[101]));
 273 }
 274 #elif defined (TARGET_SPARC)
 275 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 276 {
 277     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 278     int i;
 279
 280     /* fill in g0..g7 */
 281     for(i = 0; i < 7; i++) {
 282         registers[i] = tswapl(env->gregs[i]);
 283     }
 284     /* fill in register window */
 285     for(i = 0; i < 24; i++) {
 286         registers[i + 8] = tswapl(env->regwptr[i]);
 287     }
 288     /* fill in fprs */
 289     for (i = 0; i < 32; i++) {
 290         registers[i + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 291     }
 292     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 293     registers[64] = tswapl(env->y);
 294     tmp = GET_PSR(env);
 295     registers[65] = tswapl(tmp);
 296     registers[66] = tswapl(env->wim);
 297     registers[67] = tswapl(env->tbr);
 298     registers[68] = tswapl(env->pc);
 299     registers[69] = tswapl(env->npc);
 300     registers[70] = tswapl(env->fsr);
 301     registers[71] = 0; /* csr */
 302     registers[72] = 0;
 303
 304     return 73 * 4;
 305 }
 306
 307 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 308 {
 309     uint32_t *registers = (uint32_t *)mem_buf;
 310     int i;
 311
 312     /* fill in g0..g7 */
 313     for(i = 0; i < 7; i++) {
 314         env->gregs[i] = tswapl(registers[i]);
 315     }
 316     /* fill in register window */
 317     for(i = 0; i < 24; i++) {
 318         env->regwptr[i] = tswapl(registers[i]);
 319     }
 320     /* fill in fprs */
 321     for (i = 0; i < 32; i++) {
 322         *((uint32_t *)&env->fpr[i]) = tswapl(registers[i + 32]);
 323     }
 324     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 325     env->y = tswapl(registers[64]);
 326     PUT_PSR(env, tswapl(registers[65]));
 327     env->wim = tswapl(registers[66]);
 328     env->tbr = tswapl(registers[67]);
 329     env->pc = tswapl(registers[68]);
 330     env->npc = tswapl(registers[69]);
 331     env->fsr = tswapl(registers[70]);
 332 }
 333 #else
 334
 335 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 336 {
 337     return 0;
 338 }
 339
 340 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 341 {
 342 }
 343
 344 #endif
 345
 346 /* port = 0 means default port */
 347 static int gdb_handle_packet(GDBState *s, const char *line_buf)
 348 {
 349     CPUState *env = cpu_single_env;
 350     const char *p;
 351     int ch, reg_size, type;
 352     char buf[4096];
 353     uint8_t mem_buf[2000];
 354     uint32_t *registers;
 355     uint32_t addr, len;
 356
 357 #ifdef DEBUG_GDB
 358     printf("command='%s'\n", line_buf);
 359 #endif
 360     p = line_buf;
 361     ch = *p++;
 362     switch(ch) {
 363     case '?':
 364         snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
 365         put_packet(s, buf);
 366         break;
 367     case 'c':
 368         if (*p != '\0') {
 369             addr = strtoul(p, (char **)&p, 16);
 370 #if defined(TARGET_I386)
 371             env->eip = addr;
 372 #elif defined (TARGET_PPC)
 373             env->nip = addr;
 374 #elif defined (TARGET_SPARC)
 375             env->pc = addr;
 376             env->npc = addr + 4;
 377 #endif
 378         }
 379         vm_start();
 380         break;
 381     case 's':
 382         if (*p != '\0') {
 383             addr = strtoul(p, (char **)&p, 16);
 384 #if defined(TARGET_I386)
 385             env->eip = addr;
 386 #elif defined (TARGET_PPC)
 387             env->nip = addr;
 388 #elif defined (TARGET_SPARC)
 389             env->pc = addr;
 390             env->npc = addr + 4;
 391 #endif
 392         }
 393         cpu_single_step(env, 1);
 394         vm_start();
 395         break;
 396     case 'g':
 397         reg_size = cpu_gdb_read_registers(env, mem_buf);
 398         memtohex(buf, mem_buf, reg_size);
 399         put_packet(s, buf);
 400         break;
 401     case 'G':
 402         registers = (void *)mem_buf;
 403         len = strlen(p) / 2;
 404         hextomem((uint8_t *)registers, p, len);
 405         cpu_gdb_write_registers(env, mem_buf, len);
 406         put_packet(s, "OK");
 407         break;
 408     case 'm':
 409         addr = strtoul(p, (char **)&p, 16);
 410         if (*p == ',')
 411             p++;
 412         len = strtoul(p, NULL, 16);
 413         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0)
 414             memset(mem_buf, 0, len);
 415         memtohex(buf, mem_buf, len);
 416         put_packet(s, buf);
 417         break;
 418     case 'M':
 419         addr = strtoul(p, (char **)&p, 16);
 420         if (*p == ',')
 421             p++;
 422         len = strtoul(p, (char **)&p, 16);
 423         if (*p == ',')
 424             p++;
 425         hextomem(mem_buf, p, len);
 426         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
 427             put_packet(s, "ENN");
 428         else
 429             put_packet(s, "OK");
 430         break;
 431     case 'Z':
 432         type = strtoul(p, (char **)&p, 16);
 433         if (*p == ',')
 434             p++;
 435         addr = strtoul(p, (char **)&p, 16);
 436         if (*p == ',')
 437             p++;
 438         len = strtoul(p, (char **)&p, 16);
 439         if (type == 0 || type == 1) {
 440             if (cpu_breakpoint_insert(env, addr) < 0)
 441                 goto breakpoint_error;
 442             put_packet(s, "OK");
 443         } else {
 444         breakpoint_error:
 445             put_packet(s, "ENN");
 446         }
 447         break;
 448     case 'z':
 449         type = strtoul(p, (char **)&p, 16);
 450         if (*p == ',')
 451             p++;
 452         addr = strtoul(p, (char **)&p, 16);
 453         if (*p == ',')
 454             p++;
 455         len = strtoul(p, (char **)&p, 16);
 456         if (type == 0 || type == 1) {
 457             cpu_breakpoint_remove(env, addr);
 458             put_packet(s, "OK");
 459         } else {
 460             goto breakpoint_error;
 461         }
 462         break;
 463     default:
 464         //        unknown_command:
 465         /* put empty packet */
 466         buf[0] = '\0';
 467         put_packet(s, buf);
 468         break;
 469     }
 470     return RS_IDLE;
 471 }
 472
 473 extern void tb_flush(CPUState *env);
 474
 475 static void gdb_vm_stopped(void *opaque, int reason)
 476 {
 477     GDBState *s = opaque;
 478     char buf[256];
 479     int ret;
 480
 481     /* disable single step if it was enable */
 482     cpu_single_step(cpu_single_env, 0);
 483
 484     if (reason == EXCP_DEBUG) {
 485         tb_flush(cpu_single_env);
 486         ret = SIGTRAP;
 487     }
 488     else
 489         ret = 0;
 490     snprintf(buf, sizeof(buf), "S%02x", ret);
 491     put_packet(s, buf);
 492 }
 493
 494 static void gdb_read_byte(GDBState *s, int ch)
 495 {
 496     int i, csum;
 497     char reply[1];
 498
 499     if (vm_running) {
 500         /* when the CPU is running, we cannot do anything except stop
 501            it when receiving a char */
 502         vm_stop(EXCP_INTERRUPT);
 503     } else {
 504         switch(s->state) {
 505         case RS_IDLE:
 506             if (ch == '$') {
 507                 s->line_buf_index = 0;
 508                 s->state = RS_GETLINE;
 509             }
 510             break;
 511         case RS_GETLINE:
 512             if (ch == '#') {
 513             s->state = RS_CHKSUM1;
 514             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
 515                 s->state = RS_IDLE;
 516             } else {
 517             s->line_buf[s->line_buf_index++] = ch;
 518             }
 519             break;
 520         case RS_CHKSUM1:
 521             s->line_buf[s->line_buf_index] = '\0';
 522             s->line_csum = fromhex(ch) << 4;
 523             s->state = RS_CHKSUM2;
 524             break;
 525         case RS_CHKSUM2:
 526             s->line_csum |= fromhex(ch);
 527             csum = 0;
 528             for(i = 0; i < s->line_buf_index; i++) {
 529                 csum += s->line_buf[i];
 530             }
 531             if (s->line_csum != (csum & 0xff)) {
 532                 reply[0] = '-';
 533                 put_buffer(s, reply, 1);
 534                 s->state = RS_IDLE;
 535             } else {
 536                 reply[0] = '+';
 537                 put_buffer(s, reply, 1);
 538                 s->state = gdb_handle_packet(s, s->line_buf);
 539             }
 540             break;
 541         }
 542     }
 543 }
 544
 545 static int gdb_can_read(void *opaque)
 546 {
 547     return 256;
 548 }
 549
 550 static void gdb_read(void *opaque, const uint8_t *buf, int size)
 551 {
 552     GDBState *s = opaque;
 553     int i;
 554     if (size == 0) {
 555         /* end of connection */
 556         qemu_del_vm_stop_handler(gdb_vm_stopped, s);
 557         qemu_del_fd_read_handler(s->fd);
 558         qemu_free(s);
 559         vm_start();
 560     } else {
 561         for(i = 0; i < size; i++)
 562             gdb_read_byte(s, buf[i]);
 563     }
 564 }
 565
 566 static void gdb_accept(void *opaque, const uint8_t *buf, int size)
 567 {
 568     GDBState *s;
 569     struct sockaddr_in sockaddr;
 570     socklen_t len;
 571     int val, fd;
 572
 573     for(;;) {
 574         len = sizeof(sockaddr);
 575         fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
 576         if (fd < 0 && errno != EINTR) {
 577             perror("accept");
 578             return;
 579         } else if (fd >= 0) {
 580             break;
 581         }
 582     }
 583
 584     /* set short latency */
 585     val = 1;
 586     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
 587
 588     s = qemu_mallocz(sizeof(GDBState));
 589     if (!s) {
 590         close(fd);
 591         return;
 592     }
 593     s->fd = fd;
 594
 595     fcntl(fd, F_SETFL, O_NONBLOCK);
 596
 597     /* stop the VM */
 598     vm_stop(EXCP_INTERRUPT);
 599
 600     /* start handling I/O */
 601     qemu_add_fd_read_handler(s->fd, gdb_can_read, gdb_read, s);
 602     /* when the VM is stopped, the following callback is called */
 603     qemu_add_vm_stop_handler(gdb_vm_stopped, s);
 604 }
 605
 606 static int gdbserver_open(int port)
 607 {
 608     struct sockaddr_in sockaddr;
 609     int fd, val, ret;
 610
 611     fd = socket(PF_INET, SOCK_STREAM, 0);
 612     if (fd < 0) {
 613         perror("socket");
 614         return -1;
 615     }
 616
 617     /* allow fast reuse */
 618     val = 1;
 619     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 620
 621     sockaddr.sin_family = AF_INET;
 622     sockaddr.sin_port = htons(port);
 623     sockaddr.sin_addr.s_addr = 0;
 624     ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 625     if (ret < 0) {
 626         perror("bind");
 627         return -1;
 628     }
 629     ret = listen(fd, 0);
 630     if (ret < 0) {
 631         perror("listen");
 632         return -1;
 633     }
 634     fcntl(fd, F_SETFL, O_NONBLOCK);
 635     return fd;
 636 }
 637
 638 int gdbserver_start(int port)
 639 {
 640     gdbserver_fd = gdbserver_open(port);
 641     if (gdbserver_fd < 0)
 642         return -1;
 643     /* accept connections */
 644     qemu_add_fd_read_handler(gdbserver_fd, NULL, gdb_accept, NULL);
 645     return 0;
 646 }