xref: /netbsd-src/usr.sbin/crash/crash.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f) 
1 /*	$NetBSD: crash.c,v 1.14 2020/08/17 04:15:33 mrg 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 1.14 2020/08/17 04:15:33 mrg Exp $");
35 #endif /* not lint */
36 
37 #include <ddb/ddb.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 <stdarg.h>
49 #include <stdlib.h>
50 #include <unistd.h>
51 #include <getopt.h>
52 #include <errno.h>
53 #include <histedit.h>
54 #include <paths.h>
55 #include <kvm.h>
56 #include <err.h>
57 #include <ctype.h>
58 #include <util.h>
59 
60 #include "extern.h"
61 
62 #define	MAXSTAB	(16 * 1024 * 1024)
63 
64 db_regs_t	ddb_regs;
65 
66 static kvm_t		*kd;
67 static History		*hist;
68 static HistEvent	he;
69 static EditLine		*elptr;
70 static char		imgrelease[16];
71 static FILE		*ofp;
72 
73 static struct nlist nl[] = {
74 #define	X_OSRELEASE	0
75 	{ .n_name = "_osrelease" },
76 #define	X_PANICSTR	1
77 	{ .n_name = "_panicstr" },
78 #ifdef LOCKDEBUG
79 #define	X_LOCKDEBUG	2
80 	{ .n_name = "ld_all" },
81 #endif
82 	{ .n_name = NULL },
83 };
84 
85 #ifdef LOCKDEBUG
86 struct lockdebug;
87 TAILQ_HEAD(, lockdebug) ld_all;
88 #else
89 void lockdebug_lock_print(void);
90 void lockdebug_lock_print(void) {
91 	warnx("No lockdebug support compiled in");
92 }
93 #endif
94 
95 
96 static void
97 cleanup(void)
98 {
99 	if (ofp != stdout) {
100 		(void)fflush(ofp);
101 		(void)pclose(ofp);
102 		ofp = stdout;
103 	}
104 	el_end(elptr);
105 	history_end(hist);
106 }
107 
108 void
109 db_vprintf(const char *fmt, va_list ap)
110 {
111 	char buf[1024];
112 	int b, c;
113 
114 	c = vsnprintf(buf, sizeof(buf), fmt, ap);
115 	for (b = 0; b < c; b++) {
116 		db_putchar(buf[b]);
117 	}
118 }
119 
120 void
121 db_printf(const char *fmt, ...)
122 {
123 	va_list ap;
124 
125 	va_start(ap, fmt);
126 	db_vprintf(fmt, ap);
127 	va_end(ap);
128 }
129 
130 void
131 db_write_bytes(db_addr_t addr, size_t size, const char *str)
132 {
133 
134 	if ((size_t)kvm_write(kd, addr, str, size) != size) {
135 		warnx("kvm_write(%p, %zd): %s", (void *)addr, size,
136 		    kvm_geterr(kd));
137 		longjmp(db_recover);
138 	}
139 }
140 
141 void
142 db_read_bytes(db_addr_t addr, size_t size, char *str)
143 {
144 
145 	if ((size_t)kvm_read(kd, addr, str, size) != size) {
146 		warnx("kvm_read(%p, %zd): %s", (void *)addr, size,
147 		    kvm_geterr(kd));
148 		longjmp(db_recover);
149 	}
150 }
151 
152 void *
153 db_alloc(size_t sz)
154 {
155 
156 	return emalloc(sz);
157 }
158 
159 void *
160 db_zalloc(size_t sz)
161 {
162 
163 	return ecalloc(1, sz);
164 }
165 
166 void
167 db_free(void *p, size_t sz)
168 {
169 
170 	free(p);
171 }
172 
173 static void
174 punt(void)
175 {
176 
177 	db_printf("This command can only be used in-kernel.\n");
178 }
179 
180 void
181 db_breakpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
182     const char *modif)
183 {
184 
185 	punt();
186 }
187 
188 void
189 db_continue_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
190     const char *modif)
191 {
192 
193 	db_cmd_loop_done = true;
194 }
195 
196 void
197 db_delete_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
198     const char *modif)
199 {
200 
201 	punt();
202 }
203 
204 void
205 db_deletewatch_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
206     const char *modif)
207 {
208 
209 	punt();
210 }
211 
212 
213 void
214 db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
215     const char *modif)
216 {
217 
218 	punt();
219 }
220 
221 
222 void
223 db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
224     const char *modif)
225 {
226 
227 	punt();
228 }
229 
230 
231 void
232 db_trace_until_call_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
233     const char *modif)
234 {
235 
236 	punt();
237 }
238 
239 
240 void
241 db_watchpoint_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
242     const char *modif)
243 {
244 
245 	punt();
246 }
247 
248 int
249 db_readline(char *lstart, int lsize)
250 {
251 	const char *el;
252 	char *pcmd;
253 	int cnt;
254 
255 	db_force_whitespace();
256 
257 	/* Close any open pipe. */
258 	if (ofp != stdout) {
259 		(void)fflush(ofp);
260 		(void)pclose(ofp);
261 		ofp = stdout;
262 	}
263 
264 	/* Read next command. */
265 	el = el_gets(elptr, &cnt);
266 	if (el == NULL) {	/* EOF */
267 		exit(EXIT_SUCCESS);
268 	}
269 
270 	/* Save to history, and copy to caller's buffer. */
271 	history(hist, &he, H_ENTER, el);
272 	strlcpy(lstart, el, lsize);
273 	if (cnt >= lsize) {
274 		cnt = lsize - 1;
275 	}
276 	lstart[cnt] = '\0';
277 	if (cnt > 0 && lstart[cnt - 1] == '\n') {
278 		lstart[cnt - 1] = '\0';
279 	}
280 
281 	/* Need to open a pipe? If not, return now. */
282 	pcmd = strchr(lstart, '|');
283 	if (pcmd == NULL) {
284 		return strlen(lstart);
285 	}
286 
287 	/* Open a pipe to specified command, redirect output. */
288 	assert(ofp == stdout);
289 	for (*pcmd++ = '\0'; isspace((unsigned char)*pcmd); pcmd++) {
290 		/* nothing */
291 	}
292 	errno = 0;
293 	ofp = popen(pcmd, "w");
294 	if (ofp == NULL) {
295 		warn("opening pipe for command `%s'", pcmd);
296 		*lstart = '\0';
297 	}
298 	return strlen(lstart);
299 }
300 
301 void
302 db_check_interrupt(void)
303 {
304 
305 }
306 
307 int
308 cngetc(void)
309 {
310 
311 	fprintf(stderr, "cngetc\n");
312 	abort();
313 }
314 
315 void
316 cnputc(int c)
317 {
318 
319 	putc(c, ofp);
320 }
321 
322 __dead static void
323 usage(void)
324 {
325 
326 	fprintf(stderr,
327 	    "usage: %s [-w] [-M core] [-N kernel]\n\n"
328 	    "-M core\tspecify memory file (default /dev/mem)\n"
329 	    "-N kernel\tspecify name list file (default /dev/ksyms)\n",
330 	    getprogname());
331 	exit(EXIT_FAILURE);
332 }
333 
334 static const char *
335 prompt(void)
336 {
337 
338 	return "crash> ";
339 }
340 
341 int
342 main(int argc, char **argv)
343 {
344 	const char *nlistf, *memf;
345 	uintptr_t panicstr;
346 	struct winsize ws;
347 	struct stat sb;
348 	size_t sz;
349 	void *elf;
350 	int fd, ch, flags;
351 	char c;
352 
353 	nlistf = _PATH_KSYMS;
354 	memf = _PATH_MEM;
355 	ofp = stdout;
356 	flags = O_RDONLY;
357 
358 	setprogname(argv[0]);
359 
360 	/*
361 	 * Parse options.
362 	 */
363 	while ((ch = getopt(argc, argv, "M:N:w")) != -1) {
364 		switch (ch) {
365 		case 'M':
366 			memf = optarg;
367 			break;
368 		case 'N':
369 			nlistf = optarg;
370 			break;
371 		case 'w':
372 			flags = O_RDWR;
373 			break;
374 		default:
375 			usage();
376 		}
377 	}
378 	argc -= optind;
379 	argv += optind;
380 
381 	/*
382 	 * Print a list of images, and allow user to select.
383 	 */
384 	/* XXX */
385 
386 	/*
387 	 * Open the images (crash dump and symbol table).
388 	 */
389 	kd = kvm_open(nlistf, memf, NULL, flags, getprogname());
390 	if (kd == NULL) {
391 		return EXIT_FAILURE;
392 	}
393 	fd = open(nlistf, O_RDONLY);
394 	if (fd == -1)  {
395 		err(EXIT_FAILURE, "open `%s'", nlistf);
396 	}
397 	if (fstat(fd, &sb) == -1) {
398 		err(EXIT_FAILURE, "stat `%s'", nlistf);
399 	}
400 	if ((sb.st_mode & S_IFMT) != S_IFREG) {	/* XXX ksyms */
401 		sz = MAXSTAB;
402 		elf = malloc(sz);
403 		if (elf == NULL) {
404 			err(EXIT_FAILURE, "malloc(%zu)", sz);
405 		}
406 		sz = read(fd, elf, sz);
407 		if ((ssize_t)sz == -1) {
408 			err(EXIT_FAILURE, "read `%s'", nlistf);
409 		}
410 		if (sz == MAXSTAB) {
411 			errx(EXIT_FAILURE, "symbol table > %d bytes", MAXSTAB);
412 		}
413 	} else {
414 		sz = sb.st_size;
415 		elf = mmap(NULL, sz, PROT_READ, MAP_PRIVATE|MAP_FILE, fd, 0);
416 		if (elf == MAP_FAILED) {
417 			err(EXIT_FAILURE, "mmap `%s'", nlistf);
418 		}
419 	}
420 
421 	/*
422 	 * Print kernel & crash versions.
423 	 */
424 	if (kvm_nlist(kd, nl) == -1) {
425 		errx(EXIT_FAILURE, "kvm_nlist: %s", kvm_geterr(kd));
426 	}
427 	if ((size_t)kvm_read(kd, nl[X_OSRELEASE].n_value, imgrelease,
428 	    sizeof(imgrelease)) != sizeof(imgrelease)) {
429 		errx(EXIT_FAILURE, "cannot read osrelease: %s",
430 		    kvm_geterr(kd));
431 	}
432 	printf("Crash version %s, image version %s.\n", osrelease, imgrelease);
433 	if (strcmp(osrelease, imgrelease) != 0) {
434 		printf("WARNING: versions differ, you may not be able to "
435 		    "examine this image.\n");
436 	}
437 #ifdef LOCKDEBUG
438 	if ((size_t)kvm_read(kd, nl[X_LOCKDEBUG].n_value, &ld_all,
439 	    sizeof(ld_all)) != sizeof(ld_all))
440 		printf("Kernel compiled without options LOCKDEBUG.\n");
441 #endif
442 
443 	/*
444 	 * Print the panic string, if any.
445 	 */
446 	if ((size_t)kvm_read(kd, nl[X_PANICSTR].n_value, &panicstr,
447 	    sizeof(panicstr)) != sizeof(panicstr)) {
448 		errx(EXIT_FAILURE, "cannot read panicstr: %s",
449 		    kvm_geterr(kd));
450 	}
451 	if (strcmp(memf, _PATH_MEM) == 0) {
452 		printf("Output from a running system is unreliable.\n");
453 	} else if (panicstr == 0) {
454 		printf("System does not appear to have panicked.\n");
455 	} else {
456 		printf("System panicked: ");
457 		for (;;) {
458 			if ((size_t)kvm_read(kd, panicstr, &c, sizeof(c)) !=
459 			    sizeof(c)) {
460 				errx(EXIT_FAILURE, "cannot read *panicstr: %s",
461 				    kvm_geterr(kd));
462 			}
463 			if (c == '\0') {
464 				break;
465 			}
466 			putchar(c);
467 			panicstr++;
468 		}
469 		putchar('\n');
470 	}
471 
472 	/*
473 	 * Initialize line editing.
474 	 */
475 	hist = history_init();
476 	history(hist, &he, H_SETSIZE, 100);
477 	elptr = el_init(getprogname(), stdin, stdout, stderr);
478 	el_set(elptr, EL_EDITOR, "emacs");
479 	el_set(elptr, EL_SIGNAL, 1);
480 	el_set(elptr, EL_HIST, history, hist);
481 	el_set(elptr, EL_PROMPT, prompt);
482 	el_source(elptr, NULL);
483 
484 	atexit(cleanup);
485 
486 	/*
487 	 * Initialize ddb.
488 	 */
489 	if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) != -1) {
490 		db_max_width = ws.ws_col;
491 	}
492 	db_mach_init(kd);
493 	ddb_init(sz, elf, (char *)elf + sz);
494 
495 	/*
496 	 * Debug it!
497 	 */
498 	db_command_loop();
499 
500 	/*
501 	 * Finish.
502 	 */
503 	return EXIT_SUCCESS;
504 }
505