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 = (0<<28) | (4<<24) | env->psr          \
 302         | (env->psrs? PSR_S : 0)                \
 303         | (env->psrs? PSR_PS : 0)               \
 304         | (env->psret? PSR_ET : 0)              \
 305         | env->cwp;
 306     registers[65] = tswapl(tmp);
 307     registers[66] = tswapl(env->wim);
 308     registers[67] = tswapl(env->tbr);
 309     registers[68] = tswapl(env->pc);
 310     registers[69] = tswapl(env->npc);
 311     registers[70] = tswapl(env->fsr);
 312     registers[71] = 0; /* csr */
 313     registers[72] = 0;
 314
 315     return 73 * 4;
 316 }
 317
 318 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 319 {
 320     uint32_t *registers = (uint32_t *)mem_buf, tmp;
 321     int i;
 322
 323     /* fill in g0..g7 */
 324     for(i = 0; i < 7; i++) {
 325         env->gregs[i] = tswapl(registers[i]);
 326     }
 327     /* fill in register window */
 328     for(i = 0; i < 24; i++) {
 329         env->regwptr[i] = tswapl(registers[i]);
 330     }
 331     /* fill in fprs */
 332     for (i = 0; i < 32; i++) {
 333         *((uint32_t *)&env->fpr[i]) = tswapl(registers[i + 32]);
 334     }
 335     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
 336     env->y = tswapl(registers[64]);
 337     tmp = tswapl(registers[65]);
 338     env->psr = tmp & ~PSR_ICC;
 339     env->psrs = (tmp & PSR_S)? 1 : 0;
 340     env->psrps = (tmp & PSR_PS)? 1 : 0;
 341     env->psret = (tmp & PSR_ET)? 1 : 0;
 342     env->cwp = (tmp & PSR_CWP);
 343     env->wim = tswapl(registers[66]);
 344     env->tbr = tswapl(registers[67]);
 345     env->pc = tswapl(registers[68]);
 346     env->npc = tswapl(registers[69]);
 347     env->fsr = tswapl(registers[70]);
 348 }
 349 #else
 350
 351 static int cpu_gdb_read_registers(CPUState *env, uint8_t *mem_buf)
 352 {
 353     return 0;
 354 }
 355
 356 static void cpu_gdb_write_registers(CPUState *env, uint8_t *mem_buf, int size)
 357 {
 358 }
 359
 360 #endif
 361
 362 /* port = 0 means default port */
 363 static int gdb_handle_packet(GDBState *s, const char *line_buf)
 364 {
 365     CPUState *env = cpu_single_env;
 366     const char *p;
 367     int ch, reg_size, type;
 368     char buf[4096];
 369     uint8_t mem_buf[2000];
 370     uint32_t *registers;
 371     uint32_t addr, len;
 372
 373 #ifdef DEBUG_GDB
 374     printf("command='%s'\n", line_buf);
 375 #endif
 376     p = line_buf;
 377     ch = *p++;
 378     switch(ch) {
 379     case '?':
 380         snprintf(buf, sizeof(buf), "S%02x", SIGTRAP);
 381         put_packet(s, buf);
 382         break;
 383     case 'c':
 384         if (*p != '\0') {
 385             addr = strtoul(p, (char **)&p, 16);
 386 #if defined(TARGET_I386)
 387             env->eip = addr;
 388 #elif defined (TARGET_PPC)
 389             env->nip = addr;
 390 #endif
 391         }
 392         vm_start();
 393         break;
 394     case 's':
 395         if (*p != '\0') {
 396             addr = strtoul(p, (char **)&p, 16);
 397 #if defined(TARGET_I386)
 398             env->eip = addr;
 399 #elif defined (TARGET_PPC)
 400             env->nip = addr;
 401 #endif
 402         }
 403         cpu_single_step(env, 1);
 404         vm_start();
 405         break;
 406     case 'g':
 407         reg_size = cpu_gdb_read_registers(env, mem_buf);
 408         memtohex(buf, mem_buf, reg_size);
 409         put_packet(s, buf);
 410         break;
 411     case 'G':
 412         registers = (void *)mem_buf;
 413         len = strlen(p) / 2;
 414         hextomem((uint8_t *)registers, p, len);
 415         cpu_gdb_write_registers(env, mem_buf, len);
 416         put_packet(s, "OK");
 417         break;
 418     case 'm':
 419         addr = strtoul(p, (char **)&p, 16);
 420         if (*p == ',')
 421             p++;
 422         len = strtoul(p, NULL, 16);
 423         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 0) != 0)
 424             memset(mem_buf, 0, len);
 425         memtohex(buf, mem_buf, len);
 426         put_packet(s, buf);
 427         break;
 428     case 'M':
 429         addr = strtoul(p, (char **)&p, 16);
 430         if (*p == ',')
 431             p++;
 432         len = strtoul(p, (char **)&p, 16);
 433         if (*p == ',')
 434             p++;
 435         hextomem(mem_buf, p, len);
 436         if (cpu_memory_rw_debug(env, addr, mem_buf, len, 1) != 0)
 437             put_packet(s, "ENN");
 438         else
 439             put_packet(s, "OK");
 440         break;
 441     case 'Z':
 442         type = strtoul(p, (char **)&p, 16);
 443         if (*p == ',')
 444             p++;
 445         addr = strtoul(p, (char **)&p, 16);
 446         if (*p == ',')
 447             p++;
 448         len = strtoul(p, (char **)&p, 16);
 449         if (type == 0 || type == 1) {
 450             if (cpu_breakpoint_insert(env, addr) < 0)
 451                 goto breakpoint_error;
 452             put_packet(s, "OK");
 453         } else {
 454         breakpoint_error:
 455             put_packet(s, "ENN");
 456         }
 457         break;
 458     case 'z':
 459         type = strtoul(p, (char **)&p, 16);
 460         if (*p == ',')
 461             p++;
 462         addr = strtoul(p, (char **)&p, 16);
 463         if (*p == ',')
 464             p++;
 465         len = strtoul(p, (char **)&p, 16);
 466         if (type == 0 || type == 1) {
 467             cpu_breakpoint_remove(env, addr);
 468             put_packet(s, "OK");
 469         } else {
 470             goto breakpoint_error;
 471         }
 472         break;
 473     default:
 474         //        unknown_command:
 475         /* put empty packet */
 476         buf[0] = '\0';
 477         put_packet(s, buf);
 478         break;
 479     }
 480     return RS_IDLE;
 481 }
 482
 483 static void gdb_vm_stopped(void *opaque, int reason)
 484 {
 485     GDBState *s = opaque;
 486     char buf[256];
 487     int ret;
 488
 489     /* disable single step if it was enable */
 490     cpu_single_step(cpu_single_env, 0);
 491
 492     if (reason == EXCP_DEBUG)
 493         ret = SIGTRAP;
 494     else
 495         ret = 0;
 496     snprintf(buf, sizeof(buf), "S%02x", ret);
 497     put_packet(s, buf);
 498 }
 499
 500 static void gdb_read_byte(GDBState *s, int ch)
 501 {
 502     int i, csum;
 503     char reply[1];
 504
 505     if (vm_running) {
 506         /* when the CPU is running, we cannot do anything except stop
 507            it when receiving a char */
 508         vm_stop(EXCP_INTERRUPT);
 509     } else {
 510         switch(s->state) {
 511         case RS_IDLE:
 512             if (ch == '$') {
 513                 s->line_buf_index = 0;
 514                 s->state = RS_GETLINE;
 515             }
 516             break;
 517         case RS_GETLINE:
 518             if (ch == '#') {
 519             s->state = RS_CHKSUM1;
 520             } else if (s->line_buf_index >= sizeof(s->line_buf) - 1) {
 521                 s->state = RS_IDLE;
 522             } else {
 523             s->line_buf[s->line_buf_index++] = ch;
 524             }
 525             break;
 526         case RS_CHKSUM1:
 527             s->line_buf[s->line_buf_index] = '\0';
 528             s->line_csum = fromhex(ch) << 4;
 529             s->state = RS_CHKSUM2;
 530             break;
 531         case RS_CHKSUM2:
 532             s->line_csum |= fromhex(ch);
 533             csum = 0;
 534             for(i = 0; i < s->line_buf_index; i++) {
 535                 csum += s->line_buf[i];
 536             }
 537             if (s->line_csum != (csum & 0xff)) {
 538                 reply[0] = '-';
 539                 put_buffer(s, reply, 1);
 540                 s->state = RS_IDLE;
 541             } else {
 542                 reply[0] = '+';
 543                 put_buffer(s, reply, 1);
 544                 s->state = gdb_handle_packet(s, s->line_buf);
 545             }
 546             break;
 547         }
 548     }
 549 }
 550
 551 static int gdb_can_read(void *opaque)
 552 {
 553     return 256;
 554 }
 555
 556 static void gdb_read(void *opaque, const uint8_t *buf, int size)
 557 {
 558     GDBState *s = opaque;
 559     int i;
 560     if (size == 0) {
 561         /* end of connection */
 562         qemu_del_vm_stop_handler(gdb_vm_stopped, s);
 563         qemu_del_fd_read_handler(s->fd);
 564         qemu_free(s);
 565         vm_start();
 566     } else {
 567         for(i = 0; i < size; i++)
 568             gdb_read_byte(s, buf[i]);
 569     }
 570 }
 571
 572 static void gdb_accept(void *opaque, const uint8_t *buf, int size)
 573 {
 574     GDBState *s;
 575     struct sockaddr_in sockaddr;
 576     socklen_t len;
 577     int val, fd;
 578
 579     for(;;) {
 580         len = sizeof(sockaddr);
 581         fd = accept(gdbserver_fd, (struct sockaddr *)&sockaddr, &len);
 582         if (fd < 0 && errno != EINTR) {
 583             perror("accept");
 584             return;
 585         } else if (fd >= 0) {
 586             break;
 587         }
 588     }
 589
 590     /* set short latency */
 591     val = 1;
 592     setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &val, sizeof(val));
 593
 594     s = qemu_mallocz(sizeof(GDBState));
 595     if (!s) {
 596         close(fd);
 597         return;
 598     }
 599     s->fd = fd;
 600
 601     fcntl(fd, F_SETFL, O_NONBLOCK);
 602
 603     /* stop the VM */
 604     vm_stop(EXCP_INTERRUPT);
 605
 606     /* start handling I/O */
 607     qemu_add_fd_read_handler(s->fd, gdb_can_read, gdb_read, s);
 608     /* when the VM is stopped, the following callback is called */
 609     qemu_add_vm_stop_handler(gdb_vm_stopped, s);
 610 }
 611
 612 static int gdbserver_open(int port)
 613 {
 614     struct sockaddr_in sockaddr;
 615     int fd, val, ret;
 616
 617     fd = socket(PF_INET, SOCK_STREAM, 0);
 618     if (fd < 0) {
 619         perror("socket");
 620         return -1;
 621     }
 622
 623     /* allow fast reuse */
 624     val = 1;
 625     setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
 626
 627     sockaddr.sin_family = AF_INET;
 628     sockaddr.sin_port = htons(port);
 629     sockaddr.sin_addr.s_addr = 0;
 630     ret = bind(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 631     if (ret < 0) {
 632         perror("bind");
 633         return -1;
 634     }
 635     ret = listen(fd, 0);
 636     if (ret < 0) {
 637         perror("listen");
 638         return -1;
 639     }
 640     fcntl(fd, F_SETFL, O_NONBLOCK);
 641     return fd;
 642 }
 643
 644 int gdbserver_start(int port)
 645 {
 646     gdbserver_fd = gdbserver_open(port);
 647     if (gdbserver_fd < 0)
 648         return -1;
 649     /* accept connections */
 650     qemu_add_fd_read_handler(gdbserver_fd, NULL, gdb_accept, NULL);
 651     return 0;
 652 }