xref: /dragonfly/gnu/usr.bin/gdb/kgdb/kgdb.c (revision 8a7bdfea) 
1 /*
2  * Copyright (c) 2004 Marcel Moolenaar
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  *
26  * $FreeBSD: src/gnu/usr.bin/gdb/kgdb/main.c,v 1.11 2006/01/04 23:17:52 kan Exp $
27  * $DragonFly: src/gnu/usr.bin/gdb/kgdb/kgdb.c,v 1.3 2008/01/14 21:36:38 corecode Exp $
28  */
29 
30 #include <sys/cdefs.h>
31 
32 #include <sys/param.h>
33 #include <sys/stat.h>
34 #include <sys/types.h>
35 #include <sys/ioctl.h>
36 #include <sys/resource.h>
37 #include <sys/select.h>
38 #include <sys/time.h>
39 #include <sys/wait.h>
40 #include <sys/msgbuf.h>
41 #include <errno.h>
42 #include <err.h>
43 #include <fcntl.h>
44 #include <inttypes.h>
45 #include <kvm.h>
46 #include <limits.h>
47 #include <paths.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #include <unistd.h>
52 #include <linker_set.h>
53 
54 /* libgdb stuff. */
55 #include <defs.h>
56 #include <frame.h>
57 #include <frame-unwind.h>
58 #include <inferior.h>
59 #include <interps.h>
60 #include <cli-out.h>
61 #include <main.h>
62 #include <target.h>
63 #include <top.h>
64 #include <bfd.h>
65 #include <gdbcore.h>
66 #include <target.h>
67 
68 extern void symbol_file_add_main (char *args, int from_tty);
69 
70 #include "kgdb.h"
71 
72 kvm_t *kvm;
73 static char kvm_err[_POSIX2_LINE_MAX];
74 
75 static int dumpnr;
76 static int verbose;
77 
78 static char crashdir[PATH_MAX];
79 static char *kernel;
80 static char *remote;
81 static char *vmcore;
82 
83 static void (*kgdb_new_objfile_chain)(struct objfile * objfile);
84 
85 uintptr_t
86 lookup(const char *sym)
87 {
88 	struct nlist nl[2];
89 
90 	nl[0].n_name = (char *)(uintptr_t)sym;
91 	nl[1].n_name = NULL;
92 	if (kvm_nlist(kvm, nl) != 0) {
93 		warnx("kvm_nlist(%s): %s", sym, kvm_geterr(kvm));
94 		return (0);
95 	}
96 	return (nl[0].n_value);
97 }
98 
99 static void
100 kgdb_atexit(void)
101 {
102 	if (kvm != NULL)
103 		kvm_close(kvm);
104 }
105 
106 static void
107 usage(void)
108 {
109 
110 	fprintf(stderr,
111 	    "usage: %s [-afqv] [-d crashdir] [-c core | -n dumpnr | -r device]\n"
112 	    "\t[kernel [core]]\n", getprogname());
113 	exit(1);
114 }
115 
116 static void
117 kernel_from_dumpnr(int nr)
118 {
119 	char path[PATH_MAX];
120 	FILE *info;
121 	char *s;
122 	struct stat st;
123 	int l;
124 
125 	/*
126 	 * If there's a kernel image right here in the crash directory, then
127 	 * use it.  The kernel image is either called kernel.<nr> or is in a
128 	 * subdirectory kernel.<nr> and called kernel.  The latter allows us
129 	 * to collect the modules in the same place.
130 	 */
131 	snprintf(path, sizeof(path), "%s/kernel.%d", crashdir, nr);
132 	if (stat(path, &st) == 0) {
133 		if (S_ISREG(st.st_mode)) {
134 			kernel = strdup(path);
135 			return;
136 		}
137 		if (S_ISDIR(st.st_mode)) {
138 			snprintf(path, sizeof(path), "%s/kernel.%d/kernel",
139 			    crashdir, nr);
140 			if (stat(path, &st) == 0 && S_ISREG(st.st_mode)) {
141 				kernel = strdup(path);
142 				return;
143 			}
144 		}
145 	}
146 
147 	/*
148 	 * No kernel image here.  Parse the dump header.  The kernel object
149 	 * directory can be found there and we probably have the kernel
150 	 * image still in it.  The object directory may also have a kernel
151 	 * with debugging info (called kernel.debug).  If we have a debug
152 	 * kernel, use it.
153 	 */
154 	snprintf(path, sizeof(path), "%s/info.%d", crashdir, nr);
155 	info = fopen(path, "r");
156 	if (info == NULL) {
157 		warn(path);
158 		return;
159 	}
160 	while (fgets(path, sizeof(path), info) != NULL) {
161 		l = strlen(path);
162 		if (l > 0 && path[l - 1] == '\n')
163 			path[--l] = '\0';
164 		if (strncmp(path, "    ", 4) == 0) {
165 			s = strchr(path, ':');
166 			s = (s == NULL) ? path + 4 : s + 1;
167 			l = snprintf(path, sizeof(path), "%s/kernel.debug", s);
168 			if (stat(path, &st) == -1 || !S_ISREG(st.st_mode)) {
169 				path[l - 6] = '\0';
170 				if (stat(path, &st) == -1 ||
171 				    !S_ISREG(st.st_mode))
172 					break;
173 			}
174 			kernel = strdup(path);
175 			break;
176 		}
177 	}
178 	fclose(info);
179 }
180 
181 static void
182 kgdb_new_objfile(struct objfile *objfile)
183 {
184 #if 0
185 	printf("XXX: %s(%p)\n", __func__, objfile);
186 	if (objfile != NULL) {
187 		goto out;
188 	}
189 
190 out:
191 #endif
192 	if (kgdb_new_objfile_chain != NULL)
193 		kgdb_new_objfile_chain(objfile);
194 }
195 
196 static CORE_ADDR
197 kgdb_parse(const char *exp)
198 {
199 	struct cleanup *old_chain;
200 	struct expression *expr;
201 	struct value *val;
202 	char *s;
203 	CORE_ADDR n;
204 
205 	s = strdup(exp);
206 	old_chain = make_cleanup(free_current_contents, &expr);
207 	expr = parse_expression(s);
208 	val = (expr != NULL) ? evaluate_expression(expr) : NULL;
209 	n = (val != NULL) ? value_as_address(val) : 0;
210 	do_cleanups(old_chain);
211 	free(s);
212 	return (n);
213 }
214 
215 #define	MSGBUF_SEQ_TO_POS(size, seq)	((seq) % (size))
216 
217 static void
218 kgdb_init_target(void)
219 {
220 	bfd *kern_bfd;
221 	int kern_desc;
222 
223 	kern_desc = open(kernel, O_RDONLY);
224 	if (kern_desc == -1)
225 		errx(1, "couldn't open a kernel image");
226 
227 	kern_bfd = bfd_fdopenr(kernel, gnutarget, kern_desc);
228 	if (kern_bfd == NULL) {
229 		close(kern_desc);
230 		errx(1, "\"%s\": can't open to probe ABI: %s.", kernel,
231 			bfd_errmsg (bfd_get_error ()));
232 	}
233 	bfd_set_cacheable(kern_bfd, 1);
234 
235 	if (!bfd_check_format (kern_bfd, bfd_object)) {
236 		bfd_close(kern_bfd);
237 		errx(1, "\"%s\": not in executable format: %s", kernel,
238 			bfd_errmsg(bfd_get_error()));
239         }
240 
241 	set_gdbarch_from_file (kern_bfd);
242 	bfd_close(kern_bfd);
243 
244 	frame_unwind_prepend_unwinder(current_gdbarch, &kgdb_trgt_trapframe_unwind);
245 
246 	symbol_file_add_main (kernel, 0);
247 	if (remote)
248 		push_remote_target (remote, 0);
249 	else
250 		kgdb_target();
251 }
252 
253 static void
254 kgdb_display_msgbuf(void)
255 {
256 	uintptr_t addr;
257 	struct msgbuf *bufp, buf;
258 	size_t rseq, wseq;
259 	char c;
260 
261 	/*
262 	 * Display the unread portion of the message buffer. This gives the
263 	 * user a some initial data to work from.
264 	 */
265 	addr = lookup("_msgbufp");
266 	if (addr == 0)
267 		return;
268 	read_memory((CORE_ADDR)addr, (char *)&bufp, sizeof(bufp));
269 	read_memory((CORE_ADDR)bufp, (char *)&buf, sizeof(buf));
270 	if (buf.msg_size == 0 || buf.msg_bufr == buf.msg_bufx)
271 		return;
272 	rseq = MSGBUF_SEQ_TO_POS(buf.msg_size, buf.msg_bufr);
273 	wseq = MSGBUF_SEQ_TO_POS(buf.msg_size, buf.msg_bufx);
274 
275 	printf("\nUnread portion of the kernel message buffer:\n");
276 	while (rseq < wseq) {
277 		read_memory((CORE_ADDR)buf.msg_ptr + rseq, &c, 1);
278 		putchar(c);
279 		rseq++;
280 		if (rseq == buf.msg_size)
281 			rseq = 0;
282 	}
283 	if (c != '\n')
284 		putchar('\n');
285 	putchar('\n');
286 }
287 
288 static void
289 kgdb_init(char *argv0 __unused)
290 {
291 	kgdb_init_target();
292 
293 	set_prompt("(kgdb) ");
294 	kgdb_display_msgbuf();
295 	print_stack_frame(get_selected_frame(NULL),
296 	    frame_relative_level(get_selected_frame(NULL)), 1);
297 }
298 
299 int
300 main(int argc, char *argv[])
301 {
302 	char path[PATH_MAX];
303 	struct stat st;
304 	struct captured_main_args args;
305 	char *s;
306 	int a, ch, quiet, writecore;
307 
308 	dumpnr = -1;
309 
310 	strlcpy(crashdir, "/var/crash", sizeof(crashdir));
311 	s = getenv("KGDB_CRASH_DIR");
312 	if (s != NULL)
313 		strlcpy(crashdir, s, sizeof(crashdir));
314 
315 	/* Convert long options into short options. */
316 	for (a = 1; a < argc; a++) {
317 		s = argv[a];
318 		if (s[0] == '-') {
319 			s++;
320 			/* Long options take either 1 or 2 dashes. */
321 			if (s[0] == '-')
322 				s++;
323 			if (strcmp(s, "quiet") == 0)
324 				argv[a] = "-q";
325 			else if (strcmp(s, "fullname") == 0)
326 				argv[a] = "-f";
327 		}
328 	}
329 
330 	quiet = 0;
331 	writecore = 0;
332 
333 	while ((ch = getopt(argc, argv, "ac:d:fn:qr:vw")) != -1) {
334 		switch (ch) {
335 		case 'a':
336 			annotation_level++;
337 			break;
338 		case 'c':	/* use given core file. */
339 			if (vmcore != NULL) {
340 				warnx("option %c: can only be specified once",
341 				    optopt);
342 				usage();
343 				/* NOTREACHED */
344 			}
345 			vmcore = strdup(optarg);
346 			break;
347 		case 'd':	/* lookup dumps in given directory. */
348 			strlcpy(crashdir, optarg, sizeof(crashdir));
349 			break;
350 		case 'f':
351 			annotation_level = 1;
352 			break;
353 		case 'n':	/* use dump with given number. */
354 			dumpnr = strtol(optarg, &s, 0);
355 			if (dumpnr < 0 || *s != '\0') {
356 				warnx("option %c: invalid kernel dump number",
357 				    optopt);
358 				usage();
359 				/* NOTREACHED */
360 			}
361 			break;
362 		case 'q':
363 			quiet = 1;
364 			break;
365 		case 'r':	/* use given device for remote session. */
366 			if (remote != NULL) {
367 				warnx("option %c: can only be specified once",
368 				    optopt);
369 				usage();
370 				/* NOTREACHED */
371 			}
372 			remote = strdup(optarg);
373 			break;
374 		case 'v':	/* increase verbosity. */
375 			verbose++;
376 			break;
377 		case 'w':	/* core file is writeable. */
378 			writecore = 1;
379 			break;
380 		case '?':
381 		default:
382 			usage();
383 		}
384 	}
385 
386 	if (((vmcore != NULL) ? 1 : 0) + ((dumpnr >= 0) ? 1 : 0) +
387 	    ((remote != NULL) ? 1 : 0) > 1) {
388 		warnx("options -c, -n and -r are mutually exclusive");
389 		usage();
390 		/* NOTREACHED */
391 	}
392 
393 	if (verbose > 1)
394 		warnx("using %s as the crash directory", crashdir);
395 
396 	if (argc > optind)
397 		kernel = strdup(argv[optind++]);
398 
399 	if (argc > optind && (dumpnr >= 0 || remote != NULL)) {
400 		warnx("options -n and -r do not take a core file. Ignored");
401 		optind = argc;
402 	}
403 
404 	if (dumpnr >= 0) {
405 		snprintf(path, sizeof(path), "%s/vmcore.%d", crashdir, dumpnr);
406 		if (stat(path, &st) == -1)
407 			err(1, path);
408 		if (!S_ISREG(st.st_mode))
409 			errx(1, "%s: not a regular file", path);
410 		vmcore = strdup(path);
411 	} else if (remote != NULL && remote[0] != ':' && remote[0] != '|') {
412 		if (stat(remote, &st) != 0) {
413 			snprintf(path, sizeof(path), "/dev/%s", remote);
414 			if (stat(path, &st) != 0) {
415 				err(1, "%s", remote);
416 				/* NOTREACHED */
417 			}
418 			free(remote);
419 			remote = strdup(path);
420 		}
421 		if (!S_ISCHR(st.st_mode) && !S_ISFIFO(st.st_mode)) {
422 			errx(1, "%s: not a special file, FIFO or socket",
423 			    remote);
424 			/* NOTREACHED */
425 		}
426 	} else if (argc > optind) {
427 		if (vmcore == NULL)
428 			vmcore = strdup(argv[optind++]);
429 		if (argc > optind)
430 			warnx("multiple core files specified. Ignored");
431 	} else if (vmcore == NULL && kernel == NULL) {
432 		vmcore = strdup(_PATH_MEM);
433 		kernel = strdup(getbootfile());
434 	}
435 
436 	if (verbose) {
437 		if (vmcore != NULL)
438 			warnx("core file: %s", vmcore);
439 		if (remote != NULL)
440 			warnx("device file: %s", remote);
441 		if (kernel != NULL)
442 			warnx("kernel image: %s", kernel);
443 	}
444 
445 	/*
446 	 * At this point we must either have a core file or have a kernel
447 	 * with a remote target.
448 	 */
449 	if (remote != NULL && kernel == NULL) {
450 		warnx("remote debugging requires a kernel");
451 		usage();
452 		/* NOTREACHED */
453 	}
454 	if (vmcore == NULL && remote == NULL) {
455 		warnx("need a core file or a device for remote debugging");
456 		usage();
457 		/* NOTREACHED */
458 	}
459 
460 	/* If we don't have a kernel image yet, try to find one. */
461 	if (kernel == NULL) {
462 		if (dumpnr >= 0)
463 			kernel_from_dumpnr(dumpnr);
464 
465 		if (kernel == NULL)
466 			errx(1, "couldn't find a suitable kernel image");
467 		if (verbose)
468 			warnx("kernel image: %s", kernel);
469 	}
470 
471 	if (remote == NULL) {
472 		kvm = kvm_openfiles(kernel, vmcore, NULL,
473 		    writecore ? O_RDWR : O_RDONLY, kvm_err);
474 		if (kvm == NULL)
475 			errx(1, kvm_err);
476 		atexit(kgdb_atexit);
477 		kgdb_thr_init();
478 	}
479 
480 	/* The libgdb code uses optind too. Reset it... */
481 	optind = 0;
482 
483 	memset (&args, 0, sizeof args);
484 	args.argv = argv;
485 	args.argc = 1 + quiet;
486 	if (quiet)
487 		argv[1] = "-q";
488 	argv[args.argc] = NULL;
489 	args.use_windows = 0;
490 	args.interpreter_p = INTERP_CONSOLE;
491 
492 	deprecated_init_ui_hook = kgdb_init;
493 
494 	return (gdb_main(&args));
495 }
496