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 uint32_t from_le32 (uint32_t *buf)
 222 {
 223     uint8_t *p = (uint8_t *)buf;
 224
 225     return p[0] | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
 226 }
 227
 228 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 229 {
 230     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 231     int i;
 232
 233     /* fill in gprs */
 234     for(i = 0; i < 32; i++) {
 235         registers[i] = tswapl(env->gpr[i]);
 236     }
 237     /* fill in fprs */
 238     for (i = 0; i < 32; i++) {
 239         registers[(i * 2) + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 240         registers[(i * 2) + 33] = tswapl(*((uint32_t *)&env->fpr[i] + 1));
 241     }
 242     /* nip, msr, ccr, lnk, ctr, xer, mq */
 243     registers[96] = tswapl(env->nip);
 244     registers[97] = tswapl(_load_msr(env));
 245     tmp = 0;
 246     for (i = 0; i < 8; i++)
 247         tmp |= env->crf[i] << (32 - ((i + 1) * 4));
 248     registers[98] = tswapl(tmp);
 249     registers[99] = tswapl(env->lr);
 250     registers[100] = tswapl(env->ctr);
 251     registers[101] = tswapl(_load_xer(env));
 252     registers[102] = 0;
 253
 254     return 103 * 4;
 255 }
 256
 257 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 258 {
 259     uint32_t *registers = (uint32_t *)mem_buf;
 260     int i;
 261
 262     /* fill in gprs */
 263     for (i = 0; i < 32; i++) {
 264         env->gpr[i] = tswapl(registers[i]);
 265     }
 266     /* fill in fprs */
 267     for (i = 0; i < 32; i++) {
 268         *((uint32_t *)&env->fpr[i]) = tswapl(registers[(i * 2) + 32]);
 269         *((uint32_t *)&env->fpr[i] + 1) = tswapl(registers[(i * 2) + 33]);
 270     }
 271     /* nip, msr, ccr, lnk, ctr, xer, mq */
 272     env->nip = tswapl(registers[96]);
 273     _store_msr(env, tswapl(registers[97]));
 274     registers[98] = tswapl(registers[98]);
 275     for (i = 0; i < 8; i++)
 276         env->crf[i] = (registers[98] >> (32 - ((i + 1) * 4))) & 0xF;
 277     env->lr = tswapl(registers[99]);
 278     env->ctr = tswapl(registers[100]);
 279     _store_xer(env, tswapl(registers[101]));
 280 }
 281 #elif defined (TARGET_SPARC)
 282 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 283 {
 284     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 285     int i;
 286
 287     /* fill in g0..g7 */
 288     for(i = 0; i < 7; i++) {
 289         registers[i] = tswapl(env->gregs[i]);
 290     }
 291     /* fill in register window */
 292     for(i = 0; i < 24; i++) {
 293         registers[i + 8] = tswapl(env->regwptr[i]);
 294     }
 295     /* fill in fprs */
 296     for (i = 0; i < 32; i++) {
 297         registers[i + 32] = tswapl(*((uint32_t *)&env->fpr[i]));
 298     }
 299     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 300     registers[64] = tswapl(env->y);
 301     tmp = GET_PSR(env);
 302     registers[65] = tswapl(tmp);
 303     registers[66] = tswapl(env->wim);
 304     registers[67] = tswapl(env->tbr);
 305     registers[68] = tswapl(env->pc);
 306     registers[69] = tswapl(env->npc);
 307     registers[70] = tswapl(env->fsr);
 308     registers[71] = 0; /* csr */
 309     registers[72] = 0;
 310
 311     return 73 * 4;
 312 }
 313
 314 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 315 {
 316     uint32_t *registers = (uint32_t *)mem_buf;
 317     int i;
 318
 319     /* fill in g0..g7 */
 320     for(i = 0; i < 7; i++) {
 321         env->gregs[i] = tswapl(registers[i]);
 322     }
 323     /* fill in register window */
 324     for(i = 0; i < 24; i++) {
 325         env->regwptr[i] = tswapl(registers[i]);
 326     }
 327     /* fill in fprs */
 328     for (i = 0; i < 32; i++) {
 329         *((uint32_t *)&env->fpr[i]) = tswapl(registers[i + 32]);
 330     }
 331     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 332     env->y = tswapl(registers[64]);
 333     PUT_PSR(env, tswapl(registers[65]));
 334     env->wim = tswapl(registers[66]);
 335     env->tbr = tswapl(registers[67]);
 336     env->pc = tswapl(registers[68]);
 337     env->npc = tswapl(registers[69]);
 338     env->fsr = tswapl(registers[70]);
 339 }
 340 #else
 341
 342 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 343 {
 344     return 0;
 345 }
 346
 347 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 348 {
 349 }
 350
 351 #endif
 352
 353 /* port = 0 means default port */
 354 static int gdb_handle_packet(GDBState *s, const char *line_buf)
 355 {
 356     CPUState *env = cpu_single_env;
 357     const char *p;
 358     int ch, reg_size, type;
 359     char buf[4096];
 360     uint8_t mem_buf[2000];
 361     uint32_t *registers;
 362     uint32_t addr, len;
 363
 364 #ifdef DEBUG_GDB
 365     printf("command='%s'\n", line_buf);
 366 #endif
 367     p = line_buf;
 368     ch = *p++;
 369     switch(ch) {
 370     case '?':
 371         snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
 372         put_packet(s, buf);
 373         break;
 374     case 'c':
 375         if (*p != '\0') {
 376             addr = strtoul(p, (char **)&p, 16);
 377 #if defined(TARGET_I386)
 378             env->eip = addr;
 379 #elif defined (TARGET_PPC)
 380             env->nip = addr;
 381 #elif defined (TARGET_SPARC)
 382             env->pc = addr;
 383             env->npc = addr + 4;
 384 #endif
 385         }
 386         vm_start();
 387         break;
 388     case 's':
 389         if (*p != '\0') {
 390             addr = strtoul(p, (char **)&p, 16);
 391 #if defined(TARGET_I386)
 392             env->eip = addr;
 393 #elif defined (TARGET_PPC)
 394             env->nip = addr;
 395 #elif defined (TARGET_SPARC)
 396             env->pc = addr;
 397             env->npc = addr + 4;
 398 #endif
 399         }
 400         cpu_single_step(env, 1);
 401         vm_start();
 402         break;
 403     case 'g':
 404         reg_size = cpu_gdb_read_registers(env, mem_buf);
 405         memtohex(buf, mem_buf, reg_size);
 406         put_packet(s, buf);
 407         break;
 408     case 'G':
 409         registers = (void *)mem_buf;
 410         len = strlen(p) / 2;
 411         hextomem((uint8_t *)registers, p, len);
 412         cpu_gdb_write_registers(env, mem_buf, len);
 413         put_packet(s, "OK");
 414         break;
 415     case 'm':
 416         addr = strtoul(p, (char **)&p, 16);
 417         if (*p == ',')
 418             p++;
 419         len = strtoul(p, NULL, 16);
 420         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0)
 421             memset(mem_buf, 0, len);
 422         memtohex(buf, mem_buf, len);
 423         put_packet(s, buf);
 424         break;
 425     case 'M':
 426         addr = strtoul(p, (char **)&p, 16);
 427         if (*p == ',')
 428             p++;
 429         len = strtoul(p, (char **)&p, 16);
 430         if (*p == ',')
 431             p++;
 432         hextomem(mem_buf, p, len);
 433         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
 434             put_packet(s, "ENN");
 435         else
 436             put_packet(s, "OK");
 437         break;
 438     case 'Z':
 439         type = strtoul(p, (char **)&p, 16);
 440         if (*p == ',')
 441             p++;
 442         addr = strtoul(p, (char **)&p, 16);
 443         if (*p == ',')
 444             p++;
 445         len = strtoul(p, (char **)&p, 16);
 446         if (type == 0 || type == 1) {
 447             if (cpu_breakpoint_insert(env, addr) < 0)
 448                 goto breakpoint_error;
 449             put_packet(s, "OK");
 450         } else {
 451         breakpoint_error:
 452             put_packet(s, "ENN");
 453         }
 454         break;
 455     case 'z':
 456         type = strtoul(p, (char **)&p, 16);
 457         if (*p == ',')
 458             p++;
 459         addr = strtoul(p, (char **)&p, 16);
 460         if (*p == ',')
 461             p++;
 462         len = strtoul(p, (char **)&p, 16);
 463         if (type == 0 || type == 1) {
 464             cpu_breakpoint_remove(env, addr);
 465             put_packet(s, "OK");
 466         } else {
 467             goto breakpoint_error;
 468         }
 469         break;
 470     default:
 471         //        unknown_command:
 472         /* put empty packet */
 473         buf[0] = '\0';
 474         put_packet(s, buf);
 475         break;
 476     }
 477     return RS_IDLE;
 478 }
 479
 480 static void gdb_vm_stopped(void *opaque, int reason)
 481 {
 482     GDBState *s = opaque;
 483     char buf[256];
 484     int ret;
 485
 486     /* disable single step if it was enable */
 487     cpu_single_step(cpu_single_env, 0);
 488
 489     if (reason == EXCP_DEBUG) {
 490         tb_flush(cpu_single_env);
 491         ret = SIGTRAP;
 492     }
 493     else
 494         ret = 0;
 495     snprintf(buf, sizeof(buf), "S%02x", ret);
 496     put_packet(s, buf);
 497 }
 498
 499 static void gdb_read_byte(GDBState *s, int ch)
 500 {
 501     int i, csum;
 502     char reply[1];
 503
 504     if (vm_running) {
 505         /* when the CPU is running, we cannot do anything except stop
 506            it when receiving a char */
 507         vm_stop(EXCP_INTERRUPT);
 508     } else {
 509         switch(s->state) {
 510         case RS_IDLE:
 511             if (ch == '$') {
 512                 s->line_buf_index = 0;
 513                 s->state = RS_GETLINE;
 514             }
 515             break;
 516         case RS_GETLINE:
 517             if (ch == '#') {
 518             s->state = RS_CHKSUM1;
 519             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
 520                 s->state = RS_IDLE;
 521             } else {
 522             s->line_buf[s->line_buf_index++] = ch;
 523             }
 524             break;
 525         case RS_CHKSUM1:
 526             s->line_buf[s->line_buf_index] = '\0';
 527             s->line_csum = fromhex(ch) << 4;
 528             s->state = RS_CHKSUM2;
 529             break;
 530         case RS_CHKSUM2:
 531             s->line_csum |= fromhex(ch);
 532             csum = 0;
 533             for(i = 0; i < s->line_buf_index; i++) {
 534                 csum += s->line_buf[i];
 535             }
 536             if (s->line_csum != (csum & 0xff)) {
 537                 reply[0] = '-';
 538                 put_buffer(s, reply, 1);
 539                 s->state = RS_IDLE;
 540             } else {
 541                 reply[0] = '+';
 542                 put_buffer(s, reply, 1);
 543                 s->state = gdb_handle_packet(s, s->line_buf);
 544             }
 545             break;
 546         }
 547     }
 548 }
 549
 550 static int gdb_can_read(void *opaque)
 551 {
 552     return 256;
 553 }
 554
 555 static void gdb_read(void *opaque, const uint8_t *buf, int size)
 556 {
 557     GDBState *s = opaque;
 558     int i;
 559     if (size == 0) {
 560         /* end of connection */
 561         qemu_del_vm_stop_handler(gdb_vm_stopped, s);
 562         qemu_del_fd_read_handler(s->fd);
 563         qemu_free(s);
 564         vm_start();
 565     } else {
 566         for(i = 0; i < size; i++)
 567             gdb_read_byte(s, buf[i]);
 568     }
 569 }
 570
 571 static void gdb_accept(void *opaque, const uint8_t *buf, int size)
 572 {
 573     GDBState *s;
 574     struct sockaddr_in sockaddr;
 575     socklen_t len;
 576     int val, fd;
 577
 578     for(;;) {
 579         len = sizeof(sockaddr);
 580         fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
 581         if (fd < 0 && errno != EINTR) {
 582             perror("accept");
 583             return;
 584         } else if (fd >= 0) {
 585             break;
 586         }
 587     }
 588
 589     /* set short latency */
 590     val = 1;
 591     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
 592
 593     s = qemu_mallocz(sizeof(GDBState));
 594     if (!s) {
 595         close(fd);
 596         return;
 597     }
 598     s->fd = fd;
 599
 600     fcntl(fd, F_SETFL, O_NONBLOCK);
 601
 602     /* stop the VM */
 603     vm_stop(EXCP_INTERRUPT);
 604
 605     /* start handling I/O */
 606     qemu_add_fd_read_handler(s->fd, gdb_can_read, gdb_read, s);
 607     /* when the VM is stopped, the following callback is called */
 608     qemu_add_vm_stop_handler(gdb_vm_stopped, s);
 609 }
 610
 611 static int gdbserver_open(int port)
 612 {
 613     struct sockaddr_in sockaddr;
 614     int fd, val, ret;
 615
 616     fd = socket(PF_INET, SOCK_STREAM, 0);
 617     if (fd < 0) {
 618         perror("socket");
 619         return -1;
 620     }
 621
 622     /* allow fast reuse */
 623     val = 1;
 624     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 625
 626     sockaddr.sin_family = AF_INET;
 627     sockaddr.sin_port = htons(port);
 628     sockaddr.sin_addr.s_addr = 0;
 629     ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 630     if (ret < 0) {
 631         perror("bind");
 632         return -1;
 633     }
 634     ret = listen(fd, 0);
 635     if (ret < 0) {
 636         perror("listen");
 637         return -1;
 638     }
 639     fcntl(fd, F_SETFL, O_NONBLOCK);
 640     return fd;
 641 }
 642
 643 int gdbserver_start(int port)
 644 {
 645     gdbserver_fd = gdbserver_open(port);
 646     if (gdbserver_fd < 0)
 647         return -1;
 648     /* accept connections */
 649     qemu_add_fd_read_handler(gdbserver_fd, NULL, gdb_accept, NULL);
 650     return 0;
 651 }