xref: /netbsd-src/usr.sbin/crash/crash.c (revision 1a32d96e8566669af03015336cbab3a6765f1d46) 
1 /*	$NetBSD: crash.c,v 1.17 2024/11/21 07:20:10 skrll Exp $	*/
2 
3 /*-
4  * Copyright (c) 2009 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #ifndef lint
34 __RCSID("$NetBSD: crash.c,v 1.17 2024/11/21 07:20:10 skrll Exp $");
35 #endif /* not lint */
36 
37 #include <sys/types.h>
38 
39 #include <sys/fcntl.h>
40 #include <sys/mman.h>
41 #include <sys/stat.h>
42 #include <sys/ioctl.h>
43 
44 #ifndef __mips__
45 #include <machine/frame.h>
46 #endif
47 
48 #include <ddb/ddb.h>
49 
50 #include <stdarg.h>
51 #include <stdlib.h>
52 #include <unistd.h>
53 #include <getopt.h>
54 #include <errno.h>
55 #include <histedit.h>
56 #include <paths.h>
57 #include <kvm.h>
58 #include <err.h>
59 #include <ctype.h>
60 #include <util.h>
61 
62 #include "extern.h"
63 
64 #define	MAXSTAB	(16 * 1024 * 1024)
65 
66 db_regs_t	ddb_regs;
67 
68 static kvm_t		*kd;
69 static History		*hist;
70 static HistEvent	he;
71 static EditLine		*elptr;
72 static char		imgrelease[16];
73 static FILE		*ofp;
74 
75 static struct nlist nl[] = {
76 #define	X_OSRELEASE	0
77 	{ .n_name = "_osrelease" },
78 #define	X_PANICSTR	1
79 	{ .n_name = "_panicstr" },
80 #ifdef LOCKDEBUG
81 #define	X_LOCKDEBUG	2
82 	{ .n_name = "ld_all" },
83 #endif
84 	{ .n_name = NULL },
85 };
86 
87 #ifdef LOCKDEBUG
88 struct lockdebug;
89 TAILQ_HEAD(, lockdebug) ld_all;
90 #else
91 void lockdebug_lock_print(void);
92 void lockdebug_lock_print(void) {
93 	warnx("No lockdebug support compiled in");
94 }
95 #endif
96 
97 static void
98 cleanup(void)
99 {
100 	if (ofp != stdout) {
101 		(void)fflush(ofp);
102 		(void)pclose(ofp);
103 		ofp = stdout;
104 	}
105 	el_end(elptr);
106 	history_end(hist);
107 }
108 
109 void
110 db_vprintf(const char *fmt, va_list ap)
111 {
112 	char buf[1024];
113 	int b, c;
114 
115 	c = vsnprintf(buf, sizeof(buf), fmt, ap);
116 	for (b = 0; b < c; b++) {
117 		db_putchar(buf[b]);
118 	}
119 }
120 
121 void
122 db_printf(const char *fmt, ...)
123 {
124 	va_list ap;
125 
126 	va_start(ap, fmt);
127 	db_vprintf(fmt, ap);
128 	va_end(ap);
129 }
130 
131 void
132 db_write_bytes(db_addr_t addr, size_t size, const char *str)
133 {
134 
135 	if ((size_t)kvm_write(kd, addr, str, size) != size) {
136 		warnx("kvm_write(%p, %zd): %s", (void *)addr, size,
137 		    kvm_geterr(kd));
138 		longjmp(db_recover);
139 	}
140 }
141 
142 void
143 db_read_bytes(db_addr_t addr, size_t size, char *str)
144 {
145 
146 	if ((size_t)kvm_read(kd, addr, str, size) != size) {
147 		warnx("kvm_read(%p, %zd): %s", (void *)addr, size,
148 		    kvm_geterr(kd));
149 		longjmp(db_recover);
150 	}
151 }
152 
153 void *
154 db_alloc(size_t sz)
155 {
156 
157 	return emalloc(sz);
158 }
159 
160 void *
161 db_zalloc(size_t sz)
162 {
163 
164 	return ecalloc(1, sz);
165 }
166 
167 void
168 db_free(void *p, size_t sz)
169 {
170 
171 	free(p);
172 }
173 
174 static void
175 punt(void)
176 {
177 
178 	db_printf("This command can only be used in-kernel.\n");
179 }
180 
181 void
182 db_breakpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
183     const char *modif)
184 {
185 
186 	punt();
187 }
188 
189 void
190 db_continue_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
191     const char *modif)
192 {
193 
194 	db_cmd_loop_done = true;
195 }
196 
197 void
198 db_delete_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
199     const char *modif)
200 {
201 
202 	punt();
203 }
204 
205 void
206 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
207     const char *modif)
208 {
209 
210 	punt();
211 }
212 
213 
214 void
215 db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
216     const char *modif)
217 {
218 
219 	punt();
220 }
221 
222 
223 void
224 db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
225     const char *modif)
226 {
227 
228 	punt();
229 }
230 
231 
232 void
233 db_trace_until_call_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
234     const char *modif)
235 {
236 
237 	punt();
238 }
239 
240 
241 void
242 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
243     const char *modif)
244 {
245 
246 	punt();
247 }
248 
249 int
250 db_readline(char *lstart, int lsize)
251 {
252 	const char *el;
253 	char *pcmd;
254 	int cnt;
255 
256 	db_force_whitespace();
257 
258 	/* Close any open pipe. */
259 	if (ofp != stdout) {
260 		(void)fflush(ofp);
261 		(void)pclose(ofp);
262 		ofp = stdout;
263 	}
264 
265 	/* Read next command. */
266 	el = el_gets(elptr, &cnt);
267 	if (el == NULL) {	/* EOF */
268 		exit(EXIT_SUCCESS);
269 	}
270 
271 	/* Save to history, and copy to caller's buffer. */
272 	history(hist, &he, H_ENTER, el);
273 	strlcpy(lstart, el, lsize);
274 	if (cnt >= lsize) {
275 		cnt = lsize - 1;
276 	}
277 	lstart[cnt] = '\0';
278 	if (cnt > 0 && lstart[cnt - 1] == '\n') {
279 		lstart[cnt - 1] = '\0';
280 	}
281 
282 	/* Need to open a pipe? If not, return now. */
283 	pcmd = strchr(lstart, '|');
284 	if (pcmd == NULL) {
285 		return strlen(lstart);
286 	}
287 
288 	/* Open a pipe to specified command, redirect output. */
289 	assert(ofp == stdout);
290 	for (*pcmd++ = '\0'; isspace((unsigned char)*pcmd); pcmd++) {
291 		/* nothing */
292 	}
293 	errno = 0;
294 	ofp = popen(pcmd, "w");
295 	if (ofp == NULL) {
296 		warn("opening pipe for command `%s'", pcmd);
297 		*lstart = '\0';
298 	}
299 	return strlen(lstart);
300 }
301 
302 void
303 db_check_interrupt(void)
304 {
305 
306 }
307 
308 int
309 cngetc(void)
310 {
311 	char ch;
312 
313 	if (el_getc(elptr, &ch) <= 0)
314 		return 0;
315 	return (unsigned char)ch;
316 }
317 
318 void
319 cnputc(int c)
320 {
321 
322 	putc(c, ofp);
323 }
324 
325 __dead static void
326 usage(void)
327 {
328 
329 	fprintf(stderr,
330 	    "usage: %s [-w] [-M core] [-N kernel]\n\n"
331 	    "-M core\tspecify memory file (default /dev/mem)\n"
332 	    "-N kernel\tspecify name list file (default /dev/ksyms)\n",
333 	    getprogname());
334 	exit(EXIT_FAILURE);
335 }
336 
337 static const char *
338 prompt(void)
339 {
340 
341 	return "crash> ";
342 }
343 
344 int
345 main(int argc, char **argv)
346 {
347 	const char *nlistf, *memf;
348 	uintptr_t panicstr;
349 	struct winsize ws;
350 	struct stat sb;
351 	size_t sz;
352 	void *elf;
353 	int fd, ch, flags;
354 	char c;
355 
356 	nlistf = _PATH_KSYMS;
357 	memf = _PATH_MEM;
358 	ofp = stdout;
359 	flags = O_RDONLY;
360 
361 	setprogname(argv[0]);
362 
363 	/*
364 	 * Parse options.
365 	 */
366 	while ((ch = getopt(argc, argv, "M:N:w")) != -1) {
367 		switch (ch) {
368 		case 'M':
369 			memf = optarg;
370 			break;
371 		case 'N':
372 			nlistf = optarg;
373 			break;
374 		case 'w':
375 			flags = O_RDWR;
376 			break;
377 		default:
378 			usage();
379 		}
380 	}
381 	argc -= optind;
382 	argv += optind;
383 
384 	/*
385 	 * Print a list of images, and allow user to select.
386 	 */
387 	/* XXX */
388 
389 	/*
390 	 * Open the images (crash dump and symbol table).
391 	 */
392 	kd = kvm_open(nlistf, memf, NULL, flags, getprogname());
393 	if (kd == NULL) {
394 		return EXIT_FAILURE;
395 	}
396 	fd = open(nlistf, O_RDONLY);
397 	if (fd == -1)  {
398 		err(EXIT_FAILURE, "open `%s'", nlistf);
399 	}
400 	if (fstat(fd, &sb) == -1) {
401 		err(EXIT_FAILURE, "stat `%s'", nlistf);
402 	}
403 	if ((sb.st_mode & S_IFMT) != S_IFREG) {	/* XXX ksyms */
404 		sz = MAXSTAB;
405 		elf = malloc(sz);
406 		if (elf == NULL) {
407 			err(EXIT_FAILURE, "malloc(%zu)", sz);
408 		}
409 		sz = read(fd, elf, sz);
410 		if ((ssize_t)sz == -1) {
411 			err(EXIT_FAILURE, "read `%s'", nlistf);
412 		}
413 		if (sz == MAXSTAB) {
414 			errx(EXIT_FAILURE, "symbol table > %d bytes", MAXSTAB);
415 		}
416 	} else {
417 		sz = sb.st_size;
418 		elf = mmap(NULL, sz, PROT_READ, MAP_PRIVATE|MAP_FILE, fd, 0);
419 		if (elf == MAP_FAILED) {
420 			err(EXIT_FAILURE, "mmap `%s'", nlistf);
421 		}
422 	}
423 
424 	/*
425 	 * Print kernel & crash versions.
426 	 */
427 	if (kvm_nlist(kd, nl) == -1) {
428 		errx(EXIT_FAILURE, "kvm_nlist: %s", kvm_geterr(kd));
429 	}
430 	if ((size_t)kvm_read(kd, nl[X_OSRELEASE].n_value, imgrelease,
431 	    sizeof(imgrelease)) != sizeof(imgrelease)) {
432 		errx(EXIT_FAILURE, "cannot read osrelease: %s",
433 		    kvm_geterr(kd));
434 	}
435 	printf("Crash version %s, image version %s.\n", osrelease, imgrelease);
436 	if (strcmp(osrelease, imgrelease) != 0) {
437 		printf("WARNING: versions differ, you may not be able to "
438 		    "examine this image.\n");
439 	}
440 #ifdef LOCKDEBUG
441 	if ((size_t)kvm_read(kd, nl[X_LOCKDEBUG].n_value, &ld_all,
442 	    sizeof(ld_all)) != sizeof(ld_all))
443 		printf("Kernel compiled without options LOCKDEBUG.\n");
444 #endif
445 
446 	/*
447 	 * Print the panic string, if any.
448 	 */
449 	if ((size_t)kvm_read(kd, nl[X_PANICSTR].n_value, &panicstr,
450 	    sizeof(panicstr)) != sizeof(panicstr)) {
451 		errx(EXIT_FAILURE, "cannot read panicstr: %s",
452 		    kvm_geterr(kd));
453 	}
454 	if (strcmp(memf, _PATH_MEM) == 0) {
455 		printf("Output from a running system is unreliable.\n");
456 	} else if (panicstr == 0) {
457 		printf("System does not appear to have panicked.\n");
458 	} else {
459 		printf("System panicked: ");
460 		for (;;) {
461 			if ((size_t)kvm_read(kd, panicstr, &c, sizeof(c)) !=
462 			    sizeof(c)) {
463 				errx(EXIT_FAILURE, "cannot read *panicstr: %s",
464 				    kvm_geterr(kd));
465 			}
466 			if (c == '\0') {
467 				break;
468 			}
469 			putchar(c);
470 			panicstr++;
471 		}
472 		putchar('\n');
473 	}
474 
475 	/*
476 	 * Initialize line editing.
477 	 */
478 	hist = history_init();
479 	history(hist, &he, H_SETSIZE, 100);
480 	elptr = el_init(getprogname(), stdin, stdout, stderr);
481 	el_set(elptr, EL_EDITOR, "emacs");
482 	el_set(elptr, EL_SIGNAL, 1);
483 	el_set(elptr, EL_HIST, history, hist);
484 	el_set(elptr, EL_PROMPT, prompt);
485 	el_source(elptr, NULL);
486 
487 	atexit(cleanup);
488 
489 	/*
490 	 * Initialize ddb.
491 	 */
492 	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1) {
493 		db_max_width = ws.ws_col;
494 	}
495 	db_mach_init(kd);
496 	ddb_init(sz, elf, (char *)elf + sz);
497 
498 	/*
499 	 * Debug it!
500 	 */
501 	db_command_loop();
502 
503 	/*
504 	 * Finish.
505 	 */
506 	return EXIT_SUCCESS;
507 }
508