sys/gdb/gdb_main.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2004 Marcel Moolenaar
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __FBSDID("$FreeBSD$");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/kdb.h>
  35 #include <sys/kernel.h>
  36 #include <sys/pcpu.h>
  37 #include <sys/proc.h>
  38 #include <sys/reboot.h>
  39
  40 #include <machine/gdb_machdep.h>
  41 #include <machine/kdb.h>
  42
  43 #include <gdb/gdb.h>
  44 #include <gdb/gdb_int.h>
  45
  46 static dbbe_init_f gdb_init;
  47 static dbbe_trap_f gdb_trap;
  48
  49 KDB_BACKEND(gdb, gdb_init, NULL, NULL, gdb_trap);
  50
  51 static struct gdb_dbgport null_gdb_dbgport;
  52 DATA_SET(gdb_dbgport_set, null_gdb_dbgport);
  53 SET_DECLARE(gdb_dbgport_set, struct gdb_dbgport);
  54
  55 struct gdb_dbgport *gdb_cur = NULL;
  56 int gdb_listening = 0;
  57
  58 static unsigned char gdb_bindata[64];
  59
  60 static int
  61 gdb_init(void)
  62 {
  63         struct gdb_dbgport *dp, **iter;
  64         int cur_pri, pri;
  65
  66         gdb_cur = NULL;
  67         cur_pri = -1;
  68         SET_FOREACH(iter, gdb_dbgport_set) {
  69                 dp = *iter;
  70                 pri = (dp->gdb_probe != NULL) ? dp->gdb_probe() : -1;
  71                 dp->gdb_active = (pri >= 0) ? 0 : -1;
  72                 if (pri > cur_pri) {
  73                         cur_pri = pri;
  74                         gdb_cur = dp;
  75                 }
  76         }
  77         if (gdb_cur != NULL) {
  78                 printf("GDB: debug ports:");
  79                 SET_FOREACH(iter, gdb_dbgport_set) {
  80                         dp = *iter;
  81                         if (dp->gdb_active == 0)
  82                                 printf(" %s", dp->gdb_name);
  83                 }
  84                 printf("\n");
  85         } else
  86                 printf("GDB: no debug ports present\n");
  87         if (gdb_cur != NULL) {
  88                 gdb_cur->gdb_init();
  89                 printf("GDB: current port: %s\n", gdb_cur->gdb_name);
  90         }
  91         if (gdb_cur != NULL) {
  92                 cur_pri = (boothowto & RB_GDB) ? 2 : 0;
  93                 gdb_consinit();
  94         } else
  95                 cur_pri = -1;
  96         return (cur_pri);
  97 }
  98
  99 static void
 100 gdb_do_mem_search(void)
 101 {
 102         size_t patlen;
 103         intmax_t addr, size;
 104         const unsigned char *found;
 105
 106         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ';' ||
 107             gdb_rx_varhex(&size) || gdb_rx_char() != ';' ||
 108             gdb_rx_bindata(gdb_bindata, sizeof(gdb_bindata), &patlen)) {
 109                 gdb_tx_err(EINVAL);
 110                 return;
 111         }
 112         if (gdb_search_mem((char *)(uintptr_t)addr, size, gdb_bindata,
 113             patlen, &found)) {
 114                 if (found == 0ULL)
 115                         gdb_tx_begin('0');
 116                 else {
 117                         gdb_tx_begin('1');
 118                         gdb_tx_char(',');
 119                         gdb_tx_hex((intmax_t)(uintptr_t)found, 8);
 120                 }
 121                 gdb_tx_end();
 122         } else
 123                 gdb_tx_err(EIO);
 124 }
 125
 126 static void
 127 gdb_do_threadinfo(struct thread **thr_iter)
 128 {
 129         static struct thread * const done_sentinel = (void *)(uintptr_t)1;
 130         static const size_t tidsz_hex = sizeof(lwpid_t) * 2;
 131         size_t tds_sent;
 132
 133         if (*thr_iter == NULL) {
 134                 gdb_tx_err(ENXIO);
 135                 return;
 136         }
 137
 138         if (*thr_iter == done_sentinel) {
 139                 gdb_tx_begin('l');
 140                 *thr_iter = NULL;
 141                 goto sendit;
 142         }
 143
 144         gdb_tx_begin('m');
 145
 146         for (tds_sent = 0;
 147             *thr_iter != NULL && gdb_txbuf_has_capacity(tidsz_hex + 1);
 148             *thr_iter = kdb_thr_next(*thr_iter), tds_sent++) {
 149                 if (tds_sent > 0)
 150                         gdb_tx_char(',');
 151                 gdb_tx_varhex((*thr_iter)->td_tid);
 152         }
 153
 154         /*
 155          * Can't send EOF and "some" in same packet, so set a sentinel to send
 156          * EOF when GDB asks us next.
 157          */
 158         if (*thr_iter == NULL && tds_sent > 0)
 159                 *thr_iter = done_sentinel;
 160
 161 sendit:
 162         gdb_tx_end();
 163 }
 164
 165 static int
 166 gdb_trap(int type, int code)
 167 {
 168         jmp_buf jb;
 169         struct thread *thr_iter;
 170         void *prev_jb;
 171
 172         prev_jb = kdb_jmpbuf(jb);
 173         if (setjmp(jb) != 0) {
 174                 printf("%s bailing, hopefully back to ddb!\n", __func__);
 175                 gdb_listening = 0;
 176                 (void)kdb_jmpbuf(prev_jb);
 177                 return (1);
 178         }
 179
 180         gdb_listening = 0;
 181         /*
 182          * Send a T packet. We currently do not support watchpoints (the
 183          * awatch, rwatch or watch elements).
 184          */
 185         gdb_tx_begin('T');
 186         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 187         gdb_tx_varhex(GDB_REG_PC);
 188         gdb_tx_char(':');
 189         gdb_tx_reg(GDB_REG_PC);
 190         gdb_tx_char(';');
 191         gdb_tx_str("thread:");
 192         gdb_tx_varhex((long)kdb_thread->td_tid);
 193         gdb_tx_char(';');
 194         gdb_tx_end();                   /* XXX check error condition. */
 195
 196         thr_iter = NULL;
 197         while (gdb_rx_begin() == 0) {
 198                 /* printf("GDB: got '%s'\n", gdb_rxp); */
 199                 switch (gdb_rx_char()) {
 200                 case '?':       /* Last signal. */
 201                         gdb_tx_begin('S');
 202                         gdb_tx_hex(gdb_cpu_signal(type, code), 2);
 203                         gdb_tx_end();
 204                         break;
 205                 case 'c': {     /* Continue. */
 206                         uintmax_t addr;
 207                         register_t pc;
 208                         if (!gdb_rx_varhex(&addr)) {
 209                                 pc = addr;
 210                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 211                         }
 212                         kdb_cpu_clear_singlestep();
 213                         gdb_listening = 1;
 214                         return (1);
 215                 }
 216                 case 'C': {     /* Continue with signal. */
 217                         uintmax_t addr, sig;
 218                         register_t pc;
 219                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 220                             !gdb_rx_varhex(&addr)) {
 221                                 pc = addr;
 222                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 223                         }
 224                         kdb_cpu_clear_singlestep();
 225                         gdb_listening = 1;
 226                         return (1);
 227                 }
 228                 case 'D': {     /* Detach */
 229                         gdb_tx_ok();
 230                         kdb_cpu_clear_singlestep();
 231                         return (1);
 232                 }
 233                 case 'g': {     /* Read registers. */
 234                         size_t r;
 235                         gdb_tx_begin(0);
 236                         for (r = 0; r < GDB_NREGS; r++)
 237                                 gdb_tx_reg(r);
 238                         gdb_tx_end();
 239                         break;
 240                 }
 241                 case 'G':       /* Write registers. */
 242                         gdb_tx_err(0);
 243                         break;
 244                 case 'H': {     /* Set thread. */
 245                         intmax_t tid;
 246                         struct thread *thr;
 247                         gdb_rx_char();
 248                         if (gdb_rx_varhex(&tid)) {
 249                                 gdb_tx_err(EINVAL);
 250                                 break;
 251                         }
 252                         if (tid > 0) {
 253                                 thr = kdb_thr_lookup(tid);
 254                                 if (thr == NULL) {
 255                                         gdb_tx_err(ENOENT);
 256                                         break;
 257                                 }
 258                                 kdb_thr_select(thr);
 259                         }
 260                         gdb_tx_ok();
 261                         break;
 262                 }
 263                 case 'k':       /* Kill request. */
 264                         kdb_cpu_clear_singlestep();
 265                         gdb_listening = 1;
 266                         return (1);
 267                 case 'm': {     /* Read memory. */
 268                         uintmax_t addr, size;
 269                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 270                             gdb_rx_varhex(&size)) {
 271                                 gdb_tx_err(EINVAL);
 272                                 break;
 273                         }
 274                         gdb_tx_begin(0);
 275                         if (gdb_tx_mem((char *)(uintptr_t)addr, size))
 276                                 gdb_tx_end();
 277                         else
 278                                 gdb_tx_err(EIO);
 279                         break;
 280                 }
 281                 case 'M': {     /* Write memory. */
 282                         uintmax_t addr, size;
 283                         if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
 284                             gdb_rx_varhex(&size) || gdb_rx_char() != ':') {
 285                                 gdb_tx_err(EINVAL);
 286                                 break;
 287                         }
 288                         if (gdb_rx_mem((char *)(uintptr_t)addr, size) == 0)
 289                                 gdb_tx_err(EIO);
 290                         else
 291                                 gdb_tx_ok();
 292                         break;
 293                 }
 294                 case 'P': {     /* Write register. */
 295                         char *val;
 296                         uintmax_t reg;
 297                         val = gdb_rxp;
 298                         if (gdb_rx_varhex(&reg) || gdb_rx_char() != '=' ||
 299                             !gdb_rx_mem(val, gdb_cpu_regsz(reg))) {
 300                                 gdb_tx_err(EINVAL);
 301                                 break;
 302                         }
 303                         gdb_cpu_setreg(reg, val);
 304                         gdb_tx_ok();
 305                         break;
 306                 }
 307                 case 'q':       /* General query. */
 308                         if (gdb_rx_equal("C")) {
 309                                 gdb_tx_begin('Q');
 310                                 gdb_tx_char('C');
 311                                 gdb_tx_varhex((long)kdb_thread->td_tid);
 312                                 gdb_tx_end();
 313                         } else if (gdb_rx_equal("fThreadInfo")) {
 314                                 thr_iter = kdb_thr_first();
 315                                 gdb_do_threadinfo(&thr_iter);
 316                         } else if (gdb_rx_equal("sThreadInfo")) {
 317                                 gdb_do_threadinfo(&thr_iter);
 318                         } else if (gdb_rx_equal("Search:memory:")) {
 319                                 gdb_do_mem_search();
 320                         } else if (!gdb_cpu_query())
 321                                 gdb_tx_empty();
 322                         break;
 323                 case 's': {     /* Step. */
 324                         uintmax_t addr;
 325                         register_t pc;
 326                         if (!gdb_rx_varhex(&addr)) {
 327                                 pc = addr;
 328                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 329                         }
 330                         kdb_cpu_set_singlestep();
 331                         gdb_listening = 1;
 332                         return (1);
 333                 }
 334                 case 'S': {     /* Step with signal. */
 335                         uintmax_t addr, sig;
 336                         register_t pc;
 337                         if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
 338                             !gdb_rx_varhex(&addr)) {
 339                                 pc = addr;
 340                                 gdb_cpu_setreg(GDB_REG_PC, &pc);
 341                         }
 342                         kdb_cpu_set_singlestep();
 343                         gdb_listening = 1;
 344                         return (1);
 345                 }
 346                 case 'T': {     /* Thread alive. */
 347                         intmax_t tid;
 348                         if (gdb_rx_varhex(&tid)) {
 349                                 gdb_tx_err(EINVAL);
 350                                 break;
 351                         }
 352                         if (kdb_thr_lookup(tid) != NULL)
 353                                 gdb_tx_ok();
 354                         else
 355                                 gdb_tx_err(ENOENT);
 356                         break;
 357                 }
 358                 case -1:
 359                         /* Empty command. Treat as unknown command. */
 360                         /* FALLTHROUGH */
 361                 default:
 362                         /* Unknown command. Send empty response. */
 363                         gdb_tx_empty();
 364                         break;
 365                 }
 366         }
 367         (void)kdb_jmpbuf(prev_jb);
 368         return (0);
 369 }