1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/kdb.h>
33 #include <sys/kernel.h>
34 #include <sys/pcpu.h>
35 #include <sys/proc.h>
36 #include <sys/reboot.h>
37 #include <sys/sbuf.h>
38
39 #include <machine/gdb_machdep.h>
40 #include <machine/kdb.h>
41
42 #include <gdb/gdb.h>
43 #include <gdb/gdb_int.h>
44
45 SYSCTL_NODE(_debug, OID_AUTO, gdb, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
46 "GDB settings");
47
48 static dbbe_init_f gdb_init;
49 static dbbe_trap_f gdb_trap;
50
51 KDB_BACKEND(gdb, gdb_init, NULL, NULL, gdb_trap);
52
53 static struct gdb_dbgport null_gdb_dbgport;
54 DATA_SET(gdb_dbgport_set, null_gdb_dbgport);
55 SET_DECLARE(gdb_dbgport_set, struct gdb_dbgport);
56
57 struct gdb_dbgport *gdb_cur = NULL;
58 int gdb_listening = 0;
59 bool gdb_ackmode = true;
60
61 static unsigned char gdb_bindata[64];
62
63 #ifdef DDB
64 bool gdb_return_to_ddb = false;
65 #endif
66
67 static int
gdb_init(void)68 gdb_init(void)
69 {
70 struct gdb_dbgport *dp, **iter;
71 int cur_pri, pri;
72
73 gdb_cur = NULL;
74 cur_pri = -1;
75 SET_FOREACH(iter, gdb_dbgport_set) {
76 dp = *iter;
77 pri = (dp->gdb_probe != NULL) ? dp->gdb_probe() : -1;
78 dp->gdb_active = (pri >= 0) ? 0 : -1;
79 if (pri > cur_pri) {
80 cur_pri = pri;
81 gdb_cur = dp;
82 }
83 }
84 if (gdb_cur != NULL) {
85 printf("GDB: debug ports:");
86 SET_FOREACH(iter, gdb_dbgport_set) {
87 dp = *iter;
88 if (dp->gdb_active == 0)
89 printf(" %s", dp->gdb_name);
90 }
91 printf("\n");
92 } else
93 printf("GDB: no debug ports present\n");
94 if (gdb_cur != NULL) {
95 gdb_cur->gdb_init();
96 printf("GDB: current port: %s\n", gdb_cur->gdb_name);
97 }
98 if (gdb_cur != NULL) {
99 cur_pri = (boothowto & RB_GDB) ? 2 : 0;
100 gdb_consinit();
101 } else
102 cur_pri = -1;
103 return (cur_pri);
104 }
105
106 static void
gdb_do_mem_search(void)107 gdb_do_mem_search(void)
108 {
109 size_t patlen;
110 intmax_t addr, size;
111 const unsigned char *found;
112
113 if (gdb_rx_varhex(&addr) || gdb_rx_char() != ';' ||
114 gdb_rx_varhex(&size) || gdb_rx_char() != ';' ||
115 gdb_rx_bindata(gdb_bindata, sizeof(gdb_bindata), &patlen)) {
116 gdb_tx_err(EINVAL);
117 return;
118 }
119 if (gdb_search_mem((char *)(uintptr_t)addr, size, gdb_bindata,
120 patlen, &found)) {
121 if (found == 0ULL)
122 gdb_tx_begin('0');
123 else {
124 gdb_tx_begin('1');
125 gdb_tx_char(',');
126 gdb_tx_hex((intmax_t)(uintptr_t)found, 8);
127 }
128 gdb_tx_end();
129 } else
130 gdb_tx_err(EIO);
131 }
132
133 static void
gdb_do_threadinfo(struct thread ** thr_iter)134 gdb_do_threadinfo(struct thread **thr_iter)
135 {
136 static struct thread * const done_sentinel = (void *)(uintptr_t)1;
137 static const size_t tidsz_hex = sizeof(lwpid_t) * 2;
138 size_t tds_sent;
139
140 if (*thr_iter == NULL) {
141 gdb_tx_err(ENXIO);
142 return;
143 }
144
145 if (*thr_iter == done_sentinel) {
146 gdb_tx_begin('l');
147 *thr_iter = NULL;
148 goto sendit;
149 }
150
151 gdb_tx_begin('m');
152
153 for (tds_sent = 0;
154 *thr_iter != NULL && gdb_txbuf_has_capacity(tidsz_hex + 1);
155 *thr_iter = kdb_thr_next(*thr_iter), tds_sent++) {
156 if (tds_sent > 0)
157 gdb_tx_char(',');
158 gdb_tx_varhex((*thr_iter)->td_tid);
159 }
160
161 /*
162 * Can't send EOF and "some" in same packet, so set a sentinel to send
163 * EOF when GDB asks us next.
164 */
165 if (*thr_iter == NULL && tds_sent > 0)
166 *thr_iter = done_sentinel;
167
168 sendit:
169 gdb_tx_end();
170 }
171
172 #define BIT(n) (1ull << (n))
173 enum {
174 GDB_MULTIPROCESS,
175 GDB_SWBREAK,
176 GDB_HWBREAK,
177 GDB_QRELOCINSN,
178 GDB_FORK_EVENTS,
179 GDB_VFORK_EVENTS,
180 GDB_EXEC_EVENTS,
181 GDB_VCONT_SUPPORTED,
182 GDB_QTHREADEVENTS,
183 GDB_NO_RESUMED,
184 };
185 static const char * const gdb_feature_names[] = {
186 [GDB_MULTIPROCESS] = "multiprocess",
187 [GDB_SWBREAK] = "swbreak",
188 [GDB_HWBREAK] = "hwbreak",
189 [GDB_QRELOCINSN] = "qRelocInsn",
190 [GDB_FORK_EVENTS] = "fork-events",
191 [GDB_VFORK_EVENTS] = "vfork-events",
192 [GDB_EXEC_EVENTS] = "exec-events",
193 [GDB_VCONT_SUPPORTED] = "vContSupported",
194 [GDB_QTHREADEVENTS] = "QThreadEvents",
195 [GDB_NO_RESUMED] = "no-resumed",
196 };
197 static void
gdb_do_qsupported(uint32_t * feat)198 gdb_do_qsupported(uint32_t *feat)
199 {
200 char *tok, *delim, ok;
201 size_t i, toklen;
202
203 /* Parse supported host features */
204 *feat = 0;
205 switch (gdb_rx_char()) {
206 case ':':
207 break;
208 case EOF:
209 goto nofeatures;
210 default:
211 goto error;
212 }
213
214 while (gdb_rxsz > 0) {
215 tok = gdb_rxp;
216 delim = strchrnul(gdb_rxp, ';');
217 toklen = (delim - tok);
218
219 gdb_rxp += toklen;
220 gdb_rxsz -= toklen;
221 if (*delim != '\0') {
222 *delim = '\0';
223 gdb_rxp += 1;
224 gdb_rxsz -= 1;
225 }
226
227 if (toklen < 2)
228 goto error;
229
230 ok = tok[toklen - 1];
231 if (ok != '-' && ok != '+') {
232 /*
233 * GDB only has one KV-pair feature, and we don't
234 * support it, so ignore and move on.
235 */
236 if (strchr(tok, '=') != NULL)
237 continue;
238 /* Not a KV-pair, and not a +/- flag? Malformed. */
239 goto error;
240 }
241 if (ok != '+')
242 continue;
243 tok[toklen - 1] = '\0';
244
245 for (i = 0; i < nitems(gdb_feature_names); i++)
246 if (strcmp(gdb_feature_names[i], tok) == 0)
247 break;
248
249 if (i == nitems(gdb_feature_names)) {
250 /* Unknown GDB feature. */
251 continue;
252 }
253
254 *feat |= BIT(i);
255 }
256
257 nofeatures:
258 /* Send a supported feature list back */
259 gdb_tx_begin(0);
260
261 gdb_tx_str("PacketSize");
262 gdb_tx_char('=');
263 /*
264 * We don't buffer framing bytes, but we do need to retain a byte for a
265 * trailing nul.
266 */
267 gdb_tx_varhex(GDB_BUFSZ + strlen("$#nn") - 1);
268
269 gdb_tx_str(";qXfer:threads:read+");
270
271 /*
272 * If the debugport is a reliable transport, request No Ack mode from
273 * the server. The server may or may not choose to enter No Ack mode.
274 * https://sourceware.org/gdb/onlinedocs/gdb/Packet-Acknowledgment.html
275 */
276 if (gdb_cur->gdb_dbfeatures & GDB_DBGP_FEAT_RELIABLE)
277 gdb_tx_str(";QStartNoAckMode+");
278
279 /*
280 * Future consideration:
281 * - vCont
282 * - multiprocess
283 */
284 gdb_tx_end();
285 return;
286
287 error:
288 *feat = 0;
289 gdb_tx_err(EINVAL);
290 }
291
292 /*
293 * A qXfer_context provides a vaguely generic way to generate a multi-packet
294 * response on the fly, making some assumptions about the size of sbuf writes
295 * vs actual packet length constraints. A non-byzantine gdb host should allow
296 * hundreds of bytes per packet or more.
297 *
298 * Upper layers are considered responsible for escaping the four forbidden
299 * characters '# $ } *'.
300 */
301 struct qXfer_context {
302 struct sbuf sb;
303 size_t last_offset;
304 bool flushed;
305 bool lastmessage;
306 char xfer_buf[GDB_BUFSZ];
307 };
308
309 static int
qXfer_drain(void * v,const char * buf,int len)310 qXfer_drain(void *v, const char *buf, int len)
311 {
312 struct qXfer_context *qx;
313
314 if (len < 0)
315 return (-EINVAL);
316
317 qx = v;
318 if (qx->flushed) {
319 /*
320 * Overflow. We lost some message. Maybe the packet size is
321 * ridiculously small.
322 */
323 printf("%s: Overflow in qXfer detected.\n", __func__);
324 return (-ENOBUFS);
325 }
326
327 qx->last_offset += len;
328 qx->flushed = true;
329
330 if (qx->lastmessage)
331 gdb_tx_begin('l');
332 else
333 gdb_tx_begin('m');
334
335 memcpy(gdb_txp, buf, len);
336 gdb_txp += len;
337
338 gdb_tx_end();
339 return (len);
340 }
341
342 static int
init_qXfer_ctx(struct qXfer_context * qx,uintmax_t len)343 init_qXfer_ctx(struct qXfer_context *qx, uintmax_t len)
344 {
345
346 /* Protocol (max) length field includes framing overhead. */
347 if (len < sizeof("$m#nn"))
348 return (ENOSPC);
349
350 len -= 4;
351 len = ummin(len, GDB_BUFSZ - 1);
352
353 qx->last_offset = 0;
354 qx->flushed = false;
355 qx->lastmessage = false;
356 sbuf_new(&qx->sb, qx->xfer_buf, len, SBUF_FIXEDLEN);
357 sbuf_set_drain(&qx->sb, qXfer_drain, qx);
358 return (0);
359 }
360
361 /*
362 * Squashes special XML and GDB characters down to _. Sorry.
363 */
364 static void
qXfer_escape_xmlattr_str(char * dst,size_t dstlen,const char * src)365 qXfer_escape_xmlattr_str(char *dst, size_t dstlen, const char *src)
366 {
367 static const char *forbidden = "#$}*";
368
369 size_t i;
370 char c;
371
372 for (i = 0; i < dstlen - 1 && *src != 0; src++, i++) {
373 c = *src;
374 /* XML attr filter */
375 if (c < 32)
376 c = '_';
377 /* We assume attributes will be "" quoted. */
378 if (c == '<' || c == '&' || c == '"')
379 c = '_';
380
381 /* GDB escape. */
382 if (strchr(forbidden, c) != NULL) {
383 /*
384 * It would be nice to escape these properly, but to do
385 * it correctly we need to escape them in the transmit
386 * layer, potentially doubling our buffer requirements.
387 * For now, avoid breaking the protocol by squashing
388 * them to underscore.
389 */
390 #if 0
391 *dst++ = '}';
392 c ^= 0x20;
393 #endif
394 c = '_';
395 }
396 *dst++ = c;
397 }
398 if (*src != 0)
399 printf("XXX%s: overflow; API misuse\n", __func__);
400
401 *dst = 0;
402 }
403
404 /*
405 * Dynamically generate qXfer:threads document, one packet at a time.
406 *
407 * The format is loosely described[0], although it does not seem that the
408 * <?xml?> mentioned on that page is required.
409 *
410 * [0]: https://sourceware.org/gdb/current/onlinedocs/gdb/Thread-List-Format.html
411 */
412 static void
do_qXfer_threads_read(void)413 do_qXfer_threads_read(void)
414 {
415 /* Kludgy context */
416 static struct {
417 struct qXfer_context qXfer;
418 /* Kludgy state machine */
419 struct thread *iter;
420 enum {
421 XML_START_THREAD, /* '<thread' */
422 XML_THREAD_ID, /* ' id="xxx"' */
423 XML_THREAD_CORE, /* ' core="yyy"' */
424 XML_THREAD_NAME, /* ' name="zzz"' */
425 XML_THREAD_EXTRA, /* '> ...' */
426 XML_END_THREAD, /* '</thread>' */
427 XML_SENT_END_THREADS, /* '</threads>' */
428 } next_step;
429 } ctx;
430 static char td_name_escape[MAXCOMLEN * 2 + 1];
431
432 const char *name_src;
433 uintmax_t offset, len;
434 int error;
435
436 /* Annex part must be empty. */
437 if (gdb_rx_char() != ':')
438 goto misformed_request;
439
440 if (gdb_rx_varhex(&offset) != 0 ||
441 gdb_rx_char() != ',' ||
442 gdb_rx_varhex(&len) != 0)
443 goto misformed_request;
444
445 /*
446 * Validate resume xfers.
447 */
448 if (offset != 0) {
449 if (offset != ctx.qXfer.last_offset) {
450 printf("%s: Resumed offset %ju != expected %zu\n",
451 __func__, offset, ctx.qXfer.last_offset);
452 error = ESPIPE;
453 goto request_error;
454 }
455 ctx.qXfer.flushed = false;
456 }
457
458 if (offset == 0) {
459 ctx.iter = kdb_thr_first();
460 ctx.next_step = XML_START_THREAD;
461 error = init_qXfer_ctx(&ctx.qXfer, len);
462 if (error != 0)
463 goto request_error;
464
465 sbuf_cat(&ctx.qXfer.sb, "<threads>");
466 }
467
468 while (!ctx.qXfer.flushed && ctx.iter != NULL) {
469 switch (ctx.next_step) {
470 case XML_START_THREAD:
471 ctx.next_step = XML_THREAD_ID;
472 sbuf_cat(&ctx.qXfer.sb, "<thread");
473 continue;
474
475 case XML_THREAD_ID:
476 ctx.next_step = XML_THREAD_CORE;
477 sbuf_printf(&ctx.qXfer.sb, " id=\"%jx\"",
478 (uintmax_t)ctx.iter->td_tid);
479 continue;
480
481 case XML_THREAD_CORE:
482 ctx.next_step = XML_THREAD_NAME;
483 if (ctx.iter->td_oncpu != NOCPU) {
484 sbuf_printf(&ctx.qXfer.sb, " core=\"%d\"",
485 ctx.iter->td_oncpu);
486 }
487 continue;
488
489 case XML_THREAD_NAME:
490 ctx.next_step = XML_THREAD_EXTRA;
491
492 if (ctx.iter->td_name[0] != 0)
493 name_src = ctx.iter->td_name;
494 else if (ctx.iter->td_proc != NULL &&
495 ctx.iter->td_proc->p_comm[0] != 0)
496 name_src = ctx.iter->td_proc->p_comm;
497 else
498 continue;
499
500 qXfer_escape_xmlattr_str(td_name_escape,
501 sizeof(td_name_escape), name_src);
502 sbuf_printf(&ctx.qXfer.sb, " name=\"%s\"",
503 td_name_escape);
504 continue;
505
506 case XML_THREAD_EXTRA:
507 ctx.next_step = XML_END_THREAD;
508
509 sbuf_putc(&ctx.qXfer.sb, '>');
510
511 if (TD_GET_STATE(ctx.iter) == TDS_RUNNING)
512 sbuf_cat(&ctx.qXfer.sb, "Running");
513 else if (TD_GET_STATE(ctx.iter) == TDS_RUNQ)
514 sbuf_cat(&ctx.qXfer.sb, "RunQ");
515 else if (TD_GET_STATE(ctx.iter) == TDS_CAN_RUN)
516 sbuf_cat(&ctx.qXfer.sb, "CanRun");
517 else if (TD_ON_LOCK(ctx.iter))
518 sbuf_cat(&ctx.qXfer.sb, "Blocked");
519 else if (TD_IS_SLEEPING(ctx.iter))
520 sbuf_cat(&ctx.qXfer.sb, "Sleeping");
521 else if (TD_IS_SWAPPED(ctx.iter))
522 sbuf_cat(&ctx.qXfer.sb, "Swapped");
523 else if (TD_AWAITING_INTR(ctx.iter))
524 sbuf_cat(&ctx.qXfer.sb, "IthreadWait");
525 else if (TD_IS_SUSPENDED(ctx.iter))
526 sbuf_cat(&ctx.qXfer.sb, "Suspended");
527 else
528 sbuf_cat(&ctx.qXfer.sb, "???");
529 continue;
530
531 case XML_END_THREAD:
532 ctx.next_step = XML_START_THREAD;
533 sbuf_cat(&ctx.qXfer.sb, "</thread>");
534 ctx.iter = kdb_thr_next(ctx.iter);
535 continue;
536
537 /*
538 * This one isn't part of the looping state machine,
539 * but GCC complains if you leave an enum value out of the
540 * select.
541 */
542 case XML_SENT_END_THREADS:
543 /* NOTREACHED */
544 break;
545 }
546 }
547 if (ctx.qXfer.flushed)
548 return;
549
550 if (ctx.next_step != XML_SENT_END_THREADS) {
551 ctx.next_step = XML_SENT_END_THREADS;
552 sbuf_cat(&ctx.qXfer.sb, "</threads>");
553 }
554 if (ctx.qXfer.flushed)
555 return;
556
557 ctx.qXfer.lastmessage = true;
558 sbuf_finish(&ctx.qXfer.sb);
559 sbuf_delete(&ctx.qXfer.sb);
560 ctx.qXfer.last_offset = 0;
561 return;
562
563 misformed_request:
564 /*
565 * GDB "General-Query-Packets.html" qXfer-read anchor specifically
566 * documents an E00 code for malformed requests or invalid annex.
567 * Non-zero codes indicate invalid offset or "error reading the data."
568 */
569 error = 0;
570 request_error:
571 gdb_tx_err(error);
572 return;
573 }
574
575 /*
576 * A set of standardized transfers from "special data areas."
577 *
578 * We've already matched on "qXfer:" and advanced the rx packet buffer past
579 * that bit. Parse out the rest of the packet and generate an appropriate
580 * response.
581 */
582 static void
do_qXfer(void)583 do_qXfer(void)
584 {
585 if (!gdb_rx_equal("threads:"))
586 goto unrecognized;
587
588 if (!gdb_rx_equal("read:"))
589 goto unrecognized;
590
591 do_qXfer_threads_read();
592 return;
593
594 unrecognized:
595 gdb_tx_empty();
596 return;
597 }
598
599 static void
gdb_handle_detach(void)600 gdb_handle_detach(void)
601 {
602 kdb_cpu_clear_singlestep();
603 gdb_listening = 0;
604
605 if (gdb_cur->gdb_dbfeatures & GDB_DBGP_FEAT_WANTTERM)
606 gdb_cur->gdb_term();
607
608 #ifdef DDB
609 if (!gdb_return_to_ddb)
610 return;
611
612 gdb_return_to_ddb = false;
613
614 if (kdb_dbbe_select("ddb") != 0)
615 printf("The ddb backend could not be selected.\n");
616 #endif
617 }
618
619 /*
620 * Handle a 'Z' packet: set a breakpoint or watchpoint.
621 *
622 * Currently, only watchpoints are supported.
623 */
624 static void
gdb_z_insert(void)625 gdb_z_insert(void)
626 {
627 intmax_t addr, length;
628 char ztype;
629 int error;
630
631 ztype = gdb_rx_char();
632 if (gdb_rx_char() != ',' || gdb_rx_varhex(&addr) ||
633 gdb_rx_char() != ',' || gdb_rx_varhex(&length)) {
634 error = EINVAL;
635 goto fail;
636 }
637
638 switch (ztype) {
639 case '2': /* write watchpoint */
640 error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
641 (vm_size_t)length, KDB_DBG_ACCESS_W);
642 break;
643 case '3': /* read watchpoint */
644 error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
645 (vm_size_t)length, KDB_DBG_ACCESS_R);
646 break;
647 case '4': /* access (RW) watchpoint */
648 error = kdb_cpu_set_watchpoint((vm_offset_t)addr,
649 (vm_size_t)length, KDB_DBG_ACCESS_RW);
650 break;
651 case '1': /* hardware breakpoint */
652 case '0': /* software breakpoint */
653 /* Not implemented. */
654 gdb_tx_empty();
655 return;
656 default:
657 error = EINVAL;
658 break;
659 }
660 if (error != 0)
661 goto fail;
662 gdb_tx_ok();
663 return;
664 fail:
665 gdb_tx_err(error);
666 return;
667 }
668
669 /*
670 * Handle a 'z' packet; clear a breakpoint or watchpoint.
671 *
672 * Currently, only watchpoints are supported.
673 */
674 static void
gdb_z_remove(void)675 gdb_z_remove(void)
676 {
677 intmax_t addr, length;
678 char ztype;
679 int error;
680
681 ztype = gdb_rx_char();
682 if (gdb_rx_char() != ',' || gdb_rx_varhex(&addr) ||
683 gdb_rx_char() != ',' || gdb_rx_varhex(&length)) {
684 error = EINVAL;
685 goto fail;
686 }
687
688 switch (ztype) {
689 case '2': /* write watchpoint */
690 case '3': /* read watchpoint */
691 case '4': /* access (RW) watchpoint */
692 error = kdb_cpu_clr_watchpoint((vm_offset_t)addr,
693 (vm_size_t)length);
694 break;
695 case '1': /* hardware breakpoint */
696 case '0': /* software breakpoint */
697 /* Not implemented. */
698 gdb_tx_empty();
699 return;
700 default:
701 error = EINVAL;
702 break;
703 }
704 if (error != 0)
705 goto fail;
706 gdb_tx_ok();
707 return;
708 fail:
709 gdb_tx_err(error);
710 return;
711 }
712
713 static int
gdb_trap(int type,int code)714 gdb_trap(int type, int code)
715 {
716 jmp_buf jb;
717 struct thread *thr_iter;
718 void *prev_jb;
719 uint32_t host_features;
720
721 prev_jb = kdb_jmpbuf(jb);
722 if (setjmp(jb) != 0) {
723 printf("%s bailing, hopefully back to ddb!\n", __func__);
724 gdb_listening = 0;
725 (void)kdb_jmpbuf(prev_jb);
726 return (1);
727 }
728
729 gdb_listening = 0;
730 gdb_ackmode = true;
731
732 /*
733 * Send a T packet. We currently do not support watchpoints (the
734 * awatch, rwatch or watch elements).
735 */
736 gdb_tx_begin('T');
737 gdb_tx_hex(gdb_cpu_signal(type, code), 2);
738 gdb_tx_varhex(GDB_REG_PC);
739 gdb_tx_char(':');
740 gdb_tx_reg(GDB_REG_PC);
741 gdb_tx_char(';');
742 gdb_cpu_stop_reason(type, code);
743 gdb_tx_str("thread:");
744 gdb_tx_varhex((uintmax_t)kdb_thread->td_tid);
745 gdb_tx_char(';');
746 gdb_tx_end(); /* XXX check error condition. */
747
748 thr_iter = NULL;
749 while (gdb_rx_begin() == 0) {
750 /* printf("GDB: got '%s'\n", gdb_rxp); */
751 switch (gdb_rx_char()) {
752 case '?': /* Last signal. */
753 gdb_tx_begin('T');
754 gdb_tx_hex(gdb_cpu_signal(type, code), 2);
755 gdb_tx_str("thread:");
756 gdb_tx_varhex((long)kdb_thread->td_tid);
757 gdb_tx_char(';');
758 gdb_tx_end();
759 break;
760 case 'c': { /* Continue. */
761 uintmax_t addr;
762 register_t pc;
763 if (!gdb_rx_varhex(&addr)) {
764 pc = addr;
765 gdb_cpu_setreg(GDB_REG_PC, &pc);
766 }
767 kdb_cpu_clear_singlestep();
768 gdb_listening = 1;
769 return (1);
770 }
771 case 'C': { /* Continue with signal. */
772 uintmax_t addr, sig;
773 register_t pc;
774 if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
775 !gdb_rx_varhex(&addr)) {
776 pc = addr;
777 gdb_cpu_setreg(GDB_REG_PC, &pc);
778 }
779 kdb_cpu_clear_singlestep();
780 gdb_listening = 1;
781 return (1);
782 }
783 case 'D': { /* Detach */
784 gdb_tx_ok();
785 gdb_handle_detach();
786 return (1);
787 }
788 case 'g': { /* Read registers. */
789 size_t r;
790 gdb_tx_begin(0);
791 for (r = 0; r < GDB_NREGS; r++)
792 gdb_tx_reg(r);
793 gdb_tx_end();
794 break;
795 }
796 case 'G': { /* Write registers. */
797 char *val;
798 bool success;
799 size_t r;
800 for (success = true, r = 0; r < GDB_NREGS; r++) {
801 val = gdb_rxp;
802 if (!gdb_rx_mem(val, gdb_cpu_regsz(r))) {
803 gdb_tx_err(EINVAL);
804 success = false;
805 break;
806 }
807 gdb_cpu_setreg(r, val);
808 }
809 if (success)
810 gdb_tx_ok();
811 break;
812 }
813 case 'H': { /* Set thread. */
814 intmax_t tid;
815 struct thread *thr;
816
817 /* Ignore 'g' (general) or 'c' (continue) flag. */
818 (void) gdb_rx_char();
819
820 if (gdb_rx_varhex(&tid)) {
821 gdb_tx_err(EINVAL);
822 break;
823 }
824 if (tid > 0) {
825 thr = kdb_thr_lookup(tid);
826 if (thr == NULL) {
827 gdb_tx_err(ENOENT);
828 break;
829 }
830 kdb_thr_select(thr);
831 }
832 gdb_tx_ok();
833 break;
834 }
835 case 'k': /* Kill request. */
836 gdb_handle_detach();
837 return (1);
838 case 'm': { /* Read memory. */
839 uintmax_t addr, size;
840 if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
841 gdb_rx_varhex(&size)) {
842 gdb_tx_err(EINVAL);
843 break;
844 }
845 gdb_tx_begin(0);
846 if (gdb_tx_mem((char *)(uintptr_t)addr, size))
847 gdb_tx_end();
848 else
849 gdb_tx_err(EIO);
850 break;
851 }
852 case 'M': { /* Write memory. */
853 uintmax_t addr, size;
854 if (gdb_rx_varhex(&addr) || gdb_rx_char() != ',' ||
855 gdb_rx_varhex(&size) || gdb_rx_char() != ':') {
856 gdb_tx_err(EINVAL);
857 break;
858 }
859 if (gdb_rx_mem((char *)(uintptr_t)addr, size) == 0)
860 gdb_tx_err(EIO);
861 else
862 gdb_tx_ok();
863 break;
864 }
865 case 'p': { /* Read register. */
866 uintmax_t reg;
867 if (gdb_rx_varhex(®)) {
868 gdb_tx_err(EINVAL);
869 break;
870 }
871 gdb_tx_begin(0);
872 gdb_tx_reg(reg);
873 gdb_tx_end();
874 break;
875 }
876 case 'P': { /* Write register. */
877 char *val;
878 uintmax_t reg;
879 val = gdb_rxp;
880 if (gdb_rx_varhex(®) || gdb_rx_char() != '=' ||
881 !gdb_rx_mem(val, gdb_cpu_regsz(reg))) {
882 gdb_tx_err(EINVAL);
883 break;
884 }
885 gdb_cpu_setreg(reg, val);
886 gdb_tx_ok();
887 break;
888 }
889 case 'q': /* General query. */
890 if (gdb_rx_equal("C")) {
891 gdb_tx_begin('Q');
892 gdb_tx_char('C');
893 gdb_tx_varhex((long)kdb_thread->td_tid);
894 gdb_tx_end();
895 } else if (gdb_rx_equal("Supported")) {
896 gdb_do_qsupported(&host_features);
897 } else if (gdb_rx_equal("fThreadInfo")) {
898 thr_iter = kdb_thr_first();
899 gdb_do_threadinfo(&thr_iter);
900 } else if (gdb_rx_equal("sThreadInfo")) {
901 gdb_do_threadinfo(&thr_iter);
902 } else if (gdb_rx_equal("Xfer:")) {
903 do_qXfer();
904 } else if (gdb_rx_equal("Search:memory:")) {
905 gdb_do_mem_search();
906 #ifdef __powerpc__
907 } else if (gdb_rx_equal("Offsets")) {
908 gdb_cpu_do_offsets();
909 #endif
910 } else if (!gdb_cpu_query())
911 gdb_tx_empty();
912 break;
913 case 'Q':
914 if (gdb_rx_equal("StartNoAckMode")) {
915 if ((gdb_cur->gdb_dbfeatures &
916 GDB_DBGP_FEAT_RELIABLE) == 0) {
917 /*
918 * Shouldn't happen if we didn't
919 * advertise support. Reject.
920 */
921 gdb_tx_empty();
922 break;
923 }
924 gdb_ackmode = false;
925 gdb_tx_ok();
926 } else
927 gdb_tx_empty();
928 break;
929 case 's': { /* Step. */
930 uintmax_t addr;
931 register_t pc;
932 if (!gdb_rx_varhex(&addr)) {
933 pc = addr;
934 gdb_cpu_setreg(GDB_REG_PC, &pc);
935 }
936 kdb_cpu_set_singlestep();
937 gdb_listening = 1;
938 return (1);
939 }
940 case 'S': { /* Step with signal. */
941 uintmax_t addr, sig;
942 register_t pc;
943 if (!gdb_rx_varhex(&sig) && gdb_rx_char() == ';' &&
944 !gdb_rx_varhex(&addr)) {
945 pc = addr;
946 gdb_cpu_setreg(GDB_REG_PC, &pc);
947 }
948 kdb_cpu_set_singlestep();
949 gdb_listening = 1;
950 return (1);
951 }
952 case 'T': { /* Thread alive. */
953 intmax_t tid;
954 if (gdb_rx_varhex(&tid)) {
955 gdb_tx_err(EINVAL);
956 break;
957 }
958 if (kdb_thr_lookup(tid) != NULL)
959 gdb_tx_ok();
960 else
961 gdb_tx_err(ENOENT);
962 break;
963 }
964 case 'z': { /* Remove watchpoint. */
965 gdb_z_remove();
966 break;
967 }
968 case 'Z': { /* Set watchpoint. */
969 gdb_z_insert();
970 break;
971 }
972 case EOF:
973 /* Empty command. Treat as unknown command. */
974 /* FALLTHROUGH */
975 default:
976 /* Unknown command. Send empty response. */
977 gdb_tx_empty();
978 break;
979 }
980 }
981 (void)kdb_jmpbuf(prev_jb);
982 return (0);
983 }
984