xref: /illumos-gate/usr/src/cmd/mdb/common/mdb/mdb_main.c (revision e5803b76927480e8f9b67b22201c484ccf4c2bcf)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  * Copyright 2012, Josef 'Jeff' Sipek <jeffpc@31bits.net>. All rights reserved.
25  */
26 
27 #include <sys/types.h>
28 #include <sys/mman.h>
29 #include <sys/priocntl.h>
30 #include <sys/rtpriocntl.h>
31 #include <sys/resource.h>
32 #include <sys/termios.h>
33 #include <sys/param.h>
34 #include <sys/regset.h>
35 #include <sys/frame.h>
36 #include <sys/stack.h>
37 #include <sys/reg.h>
38 
39 #include <libproc.h>
40 #include <libscf.h>
41 #include <alloca.h>
42 #include <unistd.h>
43 #include <string.h>
44 #include <stdlib.h>
45 #include <fcntl.h>
46 #include <dlfcn.h>
47 #include <libctf.h>
48 #include <errno.h>
49 #include <kvm.h>
50 
51 #include <mdb/mdb_lex.h>
52 #include <mdb/mdb_debug.h>
53 #include <mdb/mdb_signal.h>
54 #include <mdb/mdb_string.h>
55 #include <mdb/mdb_modapi.h>
56 #include <mdb/mdb_target.h>
57 #include <mdb/mdb_gelf.h>
58 #include <mdb/mdb_conf.h>
59 #include <mdb/mdb_err.h>
60 #include <mdb/mdb_io_impl.h>
61 #include <mdb/mdb_frame.h>
62 #include <mdb/mdb_set.h>
63 #include <kmdb/kmdb_kctl.h>
64 #include <mdb/mdb.h>
65 
66 #ifndef STACK_BIAS
67 #define	STACK_BIAS	0
68 #endif
69 
70 #if defined(__sparc)
71 #define	STACK_REGISTER	SP
72 #else
73 #define	STACK_REGISTER	REG_FP
74 #endif
75 
76 #ifdef _LP64
77 #define	MDB_DEF_IPATH	\
78 	"%r/usr/platform/%p/lib/adb/%i:" \
79 	"%r/usr/platform/%m/lib/adb/%i:" \
80 	"%r/usr/lib/adb/%i"
81 #define	MDB_DEF_LPATH	\
82 	"%r/usr/platform/%p/lib/mdb/%t/%i:" \
83 	"%r/usr/platform/%m/lib/mdb/%t/%i:" \
84 	"%r/usr/lib/mdb/%t/%i"
85 #else
86 #define	MDB_DEF_IPATH	\
87 	"%r/usr/platform/%p/lib/adb:" \
88 	"%r/usr/platform/%m/lib/adb:" \
89 	"%r/usr/lib/adb"
90 #define	MDB_DEF_LPATH	\
91 	"%r/usr/platform/%p/lib/mdb/%t:" \
92 	"%r/usr/platform/%m/lib/mdb/%t:" \
93 	"%r/usr/lib/mdb/%t"
94 #endif
95 
96 #define	MDB_DEF_PROMPT "> "
97 
98 /*
99  * Similar to the panic_* variables in the kernel, we keep some relevant
100  * information stored in a set of global _mdb_abort_* variables; in the
101  * event that the debugger dumps core, these will aid core dump analysis.
102  */
103 const char *volatile _mdb_abort_str;	/* reason for failure */
104 siginfo_t _mdb_abort_info;		/* signal info for fatal signal */
105 ucontext_t _mdb_abort_ctx;		/* context fatal signal interrupted */
106 int _mdb_abort_rcount;			/* number of times resume requested */
107 int _mdb_self_fd = -1;			/* fd for self as for valid_frame */
108 
109 static void
110 terminate(int status)
111 {
112 	(void) mdb_signal_blockall();
113 	mdb_destroy();
114 	exit(status);
115 }
116 
117 static void
118 print_frame(uintptr_t pc, int fnum)
119 {
120 	Dl_info dli;
121 
122 	if (dladdr((void *)pc, &dli)) {
123 		mdb_iob_printf(mdb.m_err, "    [%d] %s`%s+0x%lx()\n", fnum,
124 		    strbasename(dli.dli_fname), dli.dli_sname,
125 		    pc - (uintptr_t)dli.dli_saddr);
126 	} else
127 		mdb_iob_printf(mdb.m_err, "    [%d] %p()\n", fnum, pc);
128 }
129 
130 static int
131 valid_frame(struct frame *fr)
132 {
133 	static struct frame fake;
134 	uintptr_t addr = (uintptr_t)fr;
135 
136 	if (pread(_mdb_self_fd, &fake, sizeof (fake), addr) != sizeof (fake)) {
137 		mdb_iob_printf(mdb.m_err, "    invalid frame (%p)\n", fr);
138 		return (0);
139 	}
140 
141 	if (addr & (STACK_ALIGN - 1)) {
142 		mdb_iob_printf(mdb.m_err, "    mis-aligned frame (%p)\n", fr);
143 		return (0);
144 	}
145 
146 	return (1);
147 }
148 
149 /*ARGSUSED*/
150 static void
151 flt_handler(int sig, siginfo_t *sip, ucontext_t *ucp, void *data)
152 {
153 	static const struct rlimit rl = {
154 		(rlim_t)RLIM_INFINITY, (rlim_t)RLIM_INFINITY
155 	};
156 
157 	const mdb_idcmd_t *idcp = NULL;
158 
159 	if (mdb.m_frame != NULL && mdb.m_frame->f_cp != NULL)
160 		idcp = mdb.m_frame->f_cp->c_dcmd;
161 
162 	if (sip != NULL)
163 		bcopy(sip, &_mdb_abort_info, sizeof (_mdb_abort_info));
164 	if (ucp != NULL)
165 		bcopy(ucp, &_mdb_abort_ctx, sizeof (_mdb_abort_ctx));
166 
167 	_mdb_abort_info.si_signo = sig;
168 	(void) mdb_signal_sethandler(sig, SIG_DFL, NULL);
169 
170 	/*
171 	 * If there is no current dcmd, or the current dcmd comes from a
172 	 * builtin module, we don't allow resume and always core dump.
173 	 */
174 	if (idcp == NULL || idcp->idc_modp == NULL ||
175 	    idcp->idc_modp == &mdb.m_rmod || idcp->idc_modp->mod_hdl == NULL)
176 		goto dump;
177 
178 	if (mdb.m_term != NULL) {
179 		struct frame *fr = (struct frame *)
180 		    (ucp->uc_mcontext.gregs[STACK_REGISTER] + STACK_BIAS);
181 
182 		char signame[SIG2STR_MAX];
183 		int i = 1;
184 		char c;
185 
186 		if (sig2str(sig, signame) == -1) {
187 			mdb_iob_printf(mdb.m_err,
188 			    "\n*** %s: received signal %d at:\n",
189 			    mdb.m_pname, sig);
190 		} else {
191 			mdb_iob_printf(mdb.m_err,
192 			    "\n*** %s: received signal %s at:\n",
193 			    mdb.m_pname, signame);
194 		}
195 
196 		if (ucp->uc_mcontext.gregs[REG_PC] != 0)
197 			print_frame(ucp->uc_mcontext.gregs[REG_PC], i++);
198 
199 		while (fr != NULL && valid_frame(fr) && fr->fr_savpc != 0) {
200 			print_frame(fr->fr_savpc, i++);
201 			fr = (struct frame *)
202 			    ((uintptr_t)fr->fr_savfp + STACK_BIAS);
203 		}
204 
205 query:
206 		mdb_iob_printf(mdb.m_err, "\n%s: (c)ore dump, (q)uit, "
207 		    "(r)ecover, or (s)top for debugger [cqrs]? ", mdb.m_pname);
208 
209 		mdb_iob_flush(mdb.m_err);
210 
211 		for (;;) {
212 			if (IOP_READ(mdb.m_term, &c, sizeof (c)) != sizeof (c))
213 				goto dump;
214 
215 			switch (c) {
216 			case 'c':
217 			case 'C':
218 				(void) setrlimit(RLIMIT_CORE, &rl);
219 				mdb_iob_printf(mdb.m_err, "\n%s: attempting "
220 				    "to dump core ...\n", mdb.m_pname);
221 				goto dump;
222 
223 			case 'q':
224 			case 'Q':
225 				mdb_iob_discard(mdb.m_out);
226 				mdb_iob_nl(mdb.m_err);
227 				(void) mdb_signal_unblockall();
228 				terminate(1);
229 				/*NOTREACHED*/
230 
231 			case 'r':
232 			case 'R':
233 				mdb_iob_printf(mdb.m_err, "\n%s: unloading "
234 				    "module '%s' ...\n", mdb.m_pname,
235 				    idcp->idc_modp->mod_name);
236 
237 				(void) mdb_module_unload(
238 				    idcp->idc_modp->mod_name, 0);
239 
240 				(void) mdb_signal_sethandler(sig,
241 				    flt_handler, NULL);
242 
243 				_mdb_abort_rcount++;
244 				mdb.m_intr = 0;
245 				mdb.m_pend = 0;
246 
247 				(void) mdb_signal_unblockall();
248 				longjmp(mdb.m_frame->f_pcb, MDB_ERR_ABORT);
249 				/*NOTREACHED*/
250 
251 			case 's':
252 			case 'S':
253 				mdb_iob_printf(mdb.m_err, "\n%s: "
254 				    "attempting to stop pid %d ...\n",
255 				    mdb.m_pname, (int)getpid());
256 
257 				/*
258 				 * Stop ourself; if this fails or we are
259 				 * subsequently continued, ask again.
260 				 */
261 				(void) mdb_signal_raise(SIGSTOP);
262 				(void) mdb_signal_unblockall();
263 				goto query;
264 			}
265 		}
266 	}
267 
268 dump:
269 	if (SI_FROMUSER(sip)) {
270 		(void) mdb_signal_block(sig);
271 		(void) mdb_signal_raise(sig);
272 	}
273 
274 	(void) sigfillset(&ucp->uc_sigmask);
275 	(void) sigdelset(&ucp->uc_sigmask, sig);
276 
277 	if (_mdb_abort_str == NULL)
278 		_mdb_abort_str = "fatal signal received";
279 
280 	ucp->uc_flags |= UC_SIGMASK;
281 	(void) setcontext(ucp);
282 }
283 
284 /*ARGSUSED*/
285 static void
286 int_handler(int sig, siginfo_t *sip, ucontext_t *ucp, void *data)
287 {
288 	if (mdb.m_intr == 0)
289 		longjmp(mdb.m_frame->f_pcb, MDB_ERR_SIGINT);
290 	else
291 		mdb.m_pend++;
292 }
293 
294 static void
295 control_kmdb(int start)
296 {
297 	int fd;
298 
299 	if ((fd = open("/dev/kmdb", O_RDONLY)) < 0)
300 		die("failed to open /dev/kmdb");
301 
302 	if (start) {
303 		char *state = mdb_get_config();
304 
305 		if (ioctl(fd, KMDB_IOC_START, state) < 0)
306 			die("failed to start kmdb");
307 
308 		strfree(state);
309 	} else {
310 		if (ioctl(fd, KMDB_IOC_STOP) < 0)
311 			die("failed to stop kmdb");
312 	}
313 
314 	(void) close(fd);
315 }
316 
317 static void
318 usage(int status)
319 {
320 	mdb_iob_printf(mdb.m_err, "Usage: %s [-fkmuwyAFKMSUW] [+/-o option] "
321 	    "[-p pid] [-s dist] [-I path] [-L path]\n\t[-P prompt] "
322 	    "[-R root] [-V dis-version] [object [core] | core | suffix]\n\n",
323 	    mdb.m_pname);
324 
325 	mdb_iob_puts(mdb.m_err,
326 	    "\t-f force raw file debugging mode\n"
327 	    "\t-k force kernel debugging mode\n"
328 	    "\t-m disable demand-loading of module symbols\n"
329 	    "\t-o set specified debugger option (+o to unset)\n"
330 	    "\t-p attach to specified process-id\n"
331 	    "\t-s set symbol matching distance\n"
332 	    "\t-u force user program debugging mode\n"
333 	    "\t-w enable write mode\n"
334 	    "\t-y send terminal initialization sequences for tty mode\n"
335 	    "\t-A disable automatic loading of mdb modules\n"
336 	    "\t-F enable forcible takeover mode\n"
337 	    "\t-K stop operating system and enter live kernel debugger\n"
338 	    "\t-M preload all module symbols\n"
339 	    "\t-I set initial path for macro files\n"
340 	    "\t-L set initial path for module libs\n"
341 	    "\t-P set command-line prompt\n"
342 	    "\t-R set root directory for pathname expansion\n"
343 	    "\t-S suppress processing of ~/.mdbrc file\n"
344 	    "\t-U unload live kernel debugger\n"
345 	    "\t-W enable I/O-mapped memory access (kernel only)\n"
346 	    "\t-V set disassembler version\n");
347 
348 	terminate(status);
349 }
350 
351 static char *
352 mdb_scf_console_term(void)
353 {
354 	scf_simple_prop_t *prop;
355 	char *term = NULL;
356 
357 	if ((prop = scf_simple_prop_get(NULL,
358 	    "svc:/system/console-login:default", "ttymon",
359 	    "terminal_type")) == NULL)
360 		return (NULL);
361 
362 	if (scf_simple_prop_type(prop) == SCF_TYPE_ASTRING &&
363 	    (term = scf_simple_prop_next_astring(prop)) != NULL)
364 		term = strdup(term);
365 
366 	scf_simple_prop_free(prop);
367 	return (term);
368 }
369 
370 /*
371  * Unpleasant hack: we might be debugging a hypervisor domain dump.
372  * Earlier versions use a non-ELF file.  Later versions are ELF, but are
373  * /always/ ELF64, so our standard ehdr check isn't good enough.  Since
374  * we don't want to know too much about the file format, we'll ask
375  * mdb_kb.
376  */
377 #ifdef __x86
378 static int
379 identify_xvm_file(const char *file, int *longmode)
380 {
381 	int (*identify)(const char *, int *);
382 
383 	if (mdb_module_load("mdb_kb", MDB_MOD_GLOBAL | MDB_MOD_SILENT) != 0)
384 		return (0);
385 
386 	identify = (int (*)())dlsym(RTLD_NEXT, "xkb_identify");
387 
388 	if (identify == NULL)
389 		return (0);
390 
391 	return (identify(file, longmode));
392 }
393 #else
394 /*ARGSUSED*/
395 static int
396 identify_xvm_file(const char *file, int *longmode)
397 {
398 	return (0);
399 }
400 #endif /* __x86 */
401 
402 int
403 main(int argc, char *argv[], char *envp[])
404 {
405 	extern int mdb_kvm_is_compressed_dump(mdb_io_t *);
406 	mdb_tgt_ctor_f *tgt_ctor = NULL;
407 	const char **tgt_argv = alloca(argc * sizeof (char *));
408 	int tgt_argc = 0;
409 	mdb_tgt_t *tgt;
410 
411 	char object[MAXPATHLEN], execname[MAXPATHLEN];
412 	mdb_io_t *in_io, *out_io, *err_io, *null_io;
413 	struct termios tios;
414 	int status, c;
415 	char *p;
416 
417 	const char *Iflag = NULL, *Lflag = NULL, *Vflag = NULL, *pidarg = NULL;
418 	int fflag = 0, Kflag = 0, Rflag = 0, Sflag = 0, Oflag = 0, Uflag = 0;
419 
420 	int ttylike;
421 	int longmode = 0;
422 
423 	stack_t sigstack;
424 
425 	if (realpath(getexecname(), execname) == NULL) {
426 		(void) strncpy(execname, argv[0], MAXPATHLEN);
427 		execname[MAXPATHLEN - 1] = '\0';
428 	}
429 
430 	mdb_create(execname, argv[0]);
431 	bzero(tgt_argv, argc * sizeof (char *));
432 	argv[0] = (char *)mdb.m_pname;
433 	_mdb_self_fd = open("/proc/self/as", O_RDONLY);
434 
435 	mdb.m_env = envp;
436 
437 	out_io = mdb_fdio_create(STDOUT_FILENO);
438 	mdb.m_out = mdb_iob_create(out_io, MDB_IOB_WRONLY);
439 
440 	err_io = mdb_fdio_create(STDERR_FILENO);
441 	mdb.m_err = mdb_iob_create(err_io, MDB_IOB_WRONLY);
442 	mdb_iob_clrflags(mdb.m_err, MDB_IOB_AUTOWRAP);
443 
444 	null_io = mdb_nullio_create();
445 	mdb.m_null = mdb_iob_create(null_io, MDB_IOB_WRONLY);
446 
447 	in_io = mdb_fdio_create(STDIN_FILENO);
448 	if ((mdb.m_termtype = getenv("TERM")) != NULL) {
449 		mdb.m_termtype = strdup(mdb.m_termtype);
450 		mdb.m_flags |= MDB_FL_TERMGUESS;
451 	}
452 	mdb.m_term = NULL;
453 
454 	mdb_dmode(mdb_dstr2mode(getenv("MDB_DEBUG")));
455 	mdb.m_pgid = getpgrp();
456 
457 	if (getenv("_MDB_EXEC") != NULL)
458 		mdb.m_flags |= MDB_FL_EXEC;
459 
460 	/*
461 	 * Setup an alternate signal stack.  When tearing down pipelines in
462 	 * terminate(), we may have to destroy the stack of the context in
463 	 * which we are currently executing the signal handler.
464 	 */
465 	sigstack.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE,
466 	    MAP_PRIVATE | MAP_ANON, -1, 0);
467 	if (sigstack.ss_sp == MAP_FAILED)
468 		die("could not allocate signal stack");
469 	sigstack.ss_size = SIGSTKSZ;
470 	sigstack.ss_flags = 0;
471 	if (sigaltstack(&sigstack, NULL) != 0)
472 		die("could not set signal stack");
473 
474 	(void) mdb_signal_sethandler(SIGPIPE, SIG_IGN, NULL);
475 	(void) mdb_signal_sethandler(SIGQUIT, SIG_IGN, NULL);
476 
477 	(void) mdb_signal_sethandler(SIGILL, flt_handler, NULL);
478 	(void) mdb_signal_sethandler(SIGTRAP, flt_handler, NULL);
479 	(void) mdb_signal_sethandler(SIGIOT, flt_handler, NULL);
480 	(void) mdb_signal_sethandler(SIGEMT, flt_handler, NULL);
481 	(void) mdb_signal_sethandler(SIGFPE, flt_handler, NULL);
482 	(void) mdb_signal_sethandler(SIGBUS, flt_handler, NULL);
483 	(void) mdb_signal_sethandler(SIGSEGV, flt_handler, NULL);
484 
485 	(void) mdb_signal_sethandler(SIGHUP, (mdb_signal_f *)terminate, NULL);
486 	(void) mdb_signal_sethandler(SIGTERM, (mdb_signal_f *)terminate, NULL);
487 
488 	for (mdb.m_rdvers = RD_VERSION; mdb.m_rdvers > 0; mdb.m_rdvers--) {
489 		if (rd_init(mdb.m_rdvers) == RD_OK)
490 			break;
491 	}
492 
493 	for (mdb.m_ctfvers = CTF_VERSION; mdb.m_ctfvers > 0; mdb.m_ctfvers--) {
494 		if (ctf_version(mdb.m_ctfvers) != -1)
495 			break;
496 	}
497 
498 	if ((p = getenv("HISTSIZE")) != NULL && strisnum(p)) {
499 		mdb.m_histlen = strtoi(p);
500 		if (mdb.m_histlen < 1)
501 			mdb.m_histlen = 1;
502 	}
503 
504 	while (optind < argc) {
505 		while ((c = getopt(argc, argv,
506 		    "fkmo:p:s:uwyACD:FI:KL:MOP:R:SUV:W")) != (int)EOF) {
507 			switch (c) {
508 			case 'f':
509 				fflag++;
510 				tgt_ctor = mdb_rawfile_tgt_create;
511 				break;
512 			case 'k':
513 				tgt_ctor = mdb_kvm_tgt_create;
514 				break;
515 			case 'm':
516 				mdb.m_tgtflags |= MDB_TGT_F_NOLOAD;
517 				mdb.m_tgtflags &= ~MDB_TGT_F_PRELOAD;
518 				break;
519 			case 'o':
520 				if (!mdb_set_options(optarg, TRUE))
521 					terminate(2);
522 				break;
523 			case 'p':
524 				tgt_ctor = mdb_proc_tgt_create;
525 				pidarg = optarg;
526 				break;
527 			case 's':
528 				if (!strisnum(optarg)) {
529 					warn("expected integer following -s\n");
530 					terminate(2);
531 				}
532 				mdb.m_symdist = (size_t)(uint_t)strtoi(optarg);
533 				break;
534 			case 'u':
535 				tgt_ctor = mdb_proc_tgt_create;
536 				break;
537 			case 'w':
538 				mdb.m_tgtflags |= MDB_TGT_F_RDWR;
539 				break;
540 			case 'y':
541 				mdb.m_flags |= MDB_FL_USECUP;
542 				break;
543 			case 'A':
544 				(void) mdb_set_options("nomods", TRUE);
545 				break;
546 			case 'C':
547 				(void) mdb_set_options("noctf", TRUE);
548 				break;
549 			case 'D':
550 				mdb_dmode(mdb_dstr2mode(optarg));
551 				break;
552 			case 'F':
553 				mdb.m_tgtflags |= MDB_TGT_F_FORCE;
554 				break;
555 			case 'I':
556 				Iflag = optarg;
557 				break;
558 			case 'L':
559 				Lflag = optarg;
560 				break;
561 			case 'K':
562 				Kflag++;
563 				break;
564 			case 'M':
565 				mdb.m_tgtflags |= MDB_TGT_F_PRELOAD;
566 				mdb.m_tgtflags &= ~MDB_TGT_F_NOLOAD;
567 				break;
568 			case 'O':
569 				Oflag++;
570 				break;
571 			case 'P':
572 				if (!mdb_set_prompt(optarg))
573 					terminate(2);
574 				break;
575 			case 'R':
576 				(void) strncpy(mdb.m_root, optarg, MAXPATHLEN);
577 				mdb.m_root[MAXPATHLEN - 1] = '\0';
578 				Rflag++;
579 				break;
580 			case 'S':
581 				Sflag++;
582 				break;
583 			case 'U':
584 				Uflag++;
585 				break;
586 			case 'V':
587 				Vflag = optarg;
588 				break;
589 			case 'W':
590 				mdb.m_tgtflags |= MDB_TGT_F_ALLOWIO;
591 				break;
592 			case '?':
593 				if (optopt == '?')
594 					usage(0);
595 				/* FALLTHROUGH */
596 			default:
597 				usage(2);
598 			}
599 		}
600 
601 		if (optind < argc) {
602 			const char *arg = argv[optind++];
603 
604 			if (arg[0] == '+' && strlen(arg) == 2) {
605 				if (arg[1] != 'o') {
606 					warn("illegal option -- %s\n", arg);
607 					terminate(2);
608 				}
609 				if (optind >= argc) {
610 					warn("option requires an argument -- "
611 					    "%s\n", arg);
612 					terminate(2);
613 				}
614 				if (!mdb_set_options(argv[optind++], FALSE))
615 					terminate(2);
616 			} else
617 				tgt_argv[tgt_argc++] = arg;
618 		}
619 	}
620 
621 	if (rd_ctl(RD_CTL_SET_HELPPATH, (void *)mdb.m_root) != RD_OK) {
622 		warn("cannot set librtld_db helper path to %s\n", mdb.m_root);
623 		terminate(2);
624 	}
625 
626 	if (mdb.m_debug & MDB_DBG_HELP)
627 		terminate(0); /* Quit here if we've printed out the tokens */
628 
629 
630 	if (Iflag != NULL && strchr(Iflag, ';') != NULL) {
631 		warn("macro path cannot contain semicolons\n");
632 		terminate(2);
633 	}
634 
635 	if (Lflag != NULL && strchr(Lflag, ';') != NULL) {
636 		warn("module path cannot contain semicolons\n");
637 		terminate(2);
638 	}
639 
640 	if (Kflag || Uflag) {
641 		char *nm;
642 
643 		if (tgt_ctor != NULL || Iflag != NULL) {
644 			warn("neither -f, -k, -p, -u, nor -I "
645 			    "may be used with -K\n");
646 			usage(2);
647 		}
648 
649 		if (Lflag != NULL)
650 			mdb_set_lpath(Lflag);
651 
652 		if ((nm = ttyname(STDIN_FILENO)) == NULL ||
653 		    strcmp(nm, "/dev/console") != 0) {
654 			/*
655 			 * Due to the consequences of typing mdb -K instead of
656 			 * mdb -k on a tty other than /dev/console, we require
657 			 * -F when starting kmdb from a tty other than
658 			 * /dev/console.
659 			 */
660 			if (!(mdb.m_tgtflags & MDB_TGT_F_FORCE)) {
661 				die("-F must also be supplied to start kmdb "
662 				    "from non-console tty\n");
663 			}
664 
665 			if (mdb.m_termtype == NULL || (mdb.m_flags &
666 			    MDB_FL_TERMGUESS)) {
667 				if (mdb.m_termtype != NULL)
668 					strfree(mdb.m_termtype);
669 
670 				if ((mdb.m_termtype = mdb_scf_console_term()) !=
671 				    NULL)
672 					mdb.m_flags |= MDB_FL_TERMGUESS;
673 			}
674 		} else {
675 			/*
676 			 * When on console, $TERM (if set) takes precedence over
677 			 * the SMF setting.
678 			 */
679 			if (mdb.m_termtype == NULL && (mdb.m_termtype =
680 			    mdb_scf_console_term()) != NULL)
681 				mdb.m_flags |= MDB_FL_TERMGUESS;
682 		}
683 
684 		control_kmdb(Kflag);
685 		terminate(0);
686 		/*NOTREACHED*/
687 	}
688 
689 	/*
690 	 * If standard input appears to have tty attributes, attempt to
691 	 * initialize a terminal i/o backend on top of stdin and stdout.
692 	 */
693 	ttylike = (IOP_CTL(in_io, TCGETS, &tios) == 0);
694 	if (ttylike) {
695 		if ((mdb.m_term = mdb_termio_create(mdb.m_termtype,
696 		    in_io, out_io)) == NULL) {
697 			if (!(mdb.m_flags & MDB_FL_EXEC)) {
698 				warn("term init failed: command-line editing "
699 				    "and prompt will not be available\n");
700 			}
701 		} else {
702 			in_io = mdb.m_term;
703 		}
704 	}
705 
706 	mdb.m_in = mdb_iob_create(in_io, MDB_IOB_RDONLY);
707 	if (mdb.m_term != NULL) {
708 		mdb_iob_setpager(mdb.m_out, mdb.m_term);
709 		if (mdb.m_flags & MDB_FL_PAGER)
710 			mdb_iob_setflags(mdb.m_out, MDB_IOB_PGENABLE);
711 		else
712 			mdb_iob_clrflags(mdb.m_out, MDB_IOB_PGENABLE);
713 	} else if (ttylike)
714 		mdb_iob_setflags(mdb.m_in, MDB_IOB_TTYLIKE);
715 	else
716 		mdb_iob_setbuf(mdb.m_in, mdb_alloc(1, UM_SLEEP), 1);
717 
718 	mdb_pservice_init();
719 	mdb_lex_reset();
720 
721 	if ((mdb.m_shell = getenv("SHELL")) == NULL)
722 		mdb.m_shell = "/bin/sh";
723 
724 	/*
725 	 * If the debugger state is to be inherited from a previous instance,
726 	 * restore it now prior to path evaluation so that %R is updated.
727 	 */
728 	if ((p = getenv(MDB_CONFIG_ENV_VAR)) != NULL) {
729 		mdb_set_config(p);
730 		(void) unsetenv(MDB_CONFIG_ENV_VAR);
731 	}
732 
733 	/*
734 	 * Path evaluation part 1: Create the initial module path to allow
735 	 * the target constructor to load a support module.  Then expand
736 	 * any command-line arguments that modify the paths.
737 	 */
738 	if (Iflag != NULL)
739 		mdb_set_ipath(Iflag);
740 	else
741 		mdb_set_ipath(MDB_DEF_IPATH);
742 
743 	if (Lflag != NULL)
744 		mdb_set_lpath(Lflag);
745 	else
746 		mdb_set_lpath(MDB_DEF_LPATH);
747 
748 	if (mdb_get_prompt() == NULL && !(mdb.m_flags & MDB_FL_ADB))
749 		(void) mdb_set_prompt(MDB_DEF_PROMPT);
750 
751 	if (tgt_ctor == mdb_kvm_tgt_create) {
752 		if (pidarg != NULL) {
753 			warn("-p and -k options are mutually exclusive\n");
754 			terminate(2);
755 		}
756 
757 		if (tgt_argc == 0)
758 			tgt_argv[tgt_argc++] = "/dev/ksyms";
759 		if (tgt_argc == 1 && strisnum(tgt_argv[0]) == 0) {
760 			if (mdb.m_tgtflags & MDB_TGT_F_ALLOWIO)
761 				tgt_argv[tgt_argc++] = "/dev/allkmem";
762 			else
763 				tgt_argv[tgt_argc++] = "/dev/kmem";
764 		}
765 	}
766 
767 	if (pidarg != NULL) {
768 		if (tgt_argc != 0) {
769 			warn("-p may not be used with other arguments\n");
770 			terminate(2);
771 		}
772 		if (proc_arg_psinfo(pidarg, PR_ARG_PIDS, NULL, &status) == -1) {
773 			die("cannot attach to %s: %s\n",
774 			    pidarg, Pgrab_error(status));
775 		}
776 		if (strchr(pidarg, '/') != NULL)
777 			(void) mdb_iob_snprintf(object, MAXPATHLEN,
778 			    "%s/object/a.out", pidarg);
779 		else
780 			(void) mdb_iob_snprintf(object, MAXPATHLEN,
781 			    "/proc/%s/object/a.out", pidarg);
782 		tgt_argv[tgt_argc++] = object;
783 		tgt_argv[tgt_argc++] = pidarg;
784 	}
785 
786 	/*
787 	 * Find the first argument that is not a special "-" token.  If one is
788 	 * found, we will examine this file and make some inferences below.
789 	 */
790 	for (c = 0; c < tgt_argc && strcmp(tgt_argv[c], "-") == 0; c++)
791 		continue;
792 
793 	if (c < tgt_argc) {
794 		Elf32_Ehdr ehdr;
795 		mdb_io_t *io;
796 
797 		/*
798 		 * If special "-" tokens preceded an argument, shift the entire
799 		 * argument list to the left to remove the leading "-" args.
800 		 */
801 		if (c > 0) {
802 			bcopy(&tgt_argv[c], tgt_argv,
803 			    sizeof (const char *) * (tgt_argc - c));
804 			tgt_argc -= c;
805 		}
806 
807 		if (fflag)
808 			goto tcreate; /* skip re-exec and just create target */
809 
810 		/*
811 		 * If we just have an object file name, and that file doesn't
812 		 * exist, and it's a string of digits, infer it to be a
813 		 * sequence number referring to a pair of crash dump files.
814 		 */
815 		if (tgt_argc == 1 && access(tgt_argv[0], F_OK) == -1 &&
816 		    strisnum(tgt_argv[0])) {
817 
818 			size_t len = strlen(tgt_argv[0]) + 8;
819 			const char *object = tgt_argv[0];
820 
821 			tgt_argv[0] = mdb_alloc(len, UM_SLEEP);
822 			tgt_argv[1] = mdb_alloc(len, UM_SLEEP);
823 
824 			(void) strcpy((char *)tgt_argv[0], "unix.");
825 			(void) strcat((char *)tgt_argv[0], object);
826 			(void) strcpy((char *)tgt_argv[1], "vmcore.");
827 			(void) strcat((char *)tgt_argv[1], object);
828 
829 			if (access(tgt_argv[0], F_OK) == -1 &&
830 			    access(tgt_argv[1], F_OK) == -1) {
831 				(void) strcpy((char *)tgt_argv[1], "vmdump.");
832 				(void) strcat((char *)tgt_argv[1], object);
833 				if (access(tgt_argv[1], F_OK) == 0) {
834 					mdb_iob_printf(mdb.m_err,
835 					    "cannot open compressed dump; "
836 					    "decompress using savecore -f %s\n",
837 					    tgt_argv[1]);
838 					terminate(0);
839 				}
840 			}
841 
842 			tgt_argc = 2;
843 		}
844 
845 		/*
846 		 * We need to open the object file in order to determine its
847 		 * ELF class and potentially re-exec ourself.
848 		 */
849 		if ((io = mdb_fdio_create_path(NULL, tgt_argv[0],
850 		    O_RDONLY, 0)) == NULL)
851 			die("failed to open %s", tgt_argv[0]);
852 
853 		/*
854 		 * Check for a single vmdump.N compressed dump file,
855 		 * and give a helpful message.
856 		 */
857 		if (tgt_argc == 1) {
858 			if (mdb_kvm_is_compressed_dump(io)) {
859 				mdb_iob_printf(mdb.m_err,
860 				    "cannot open compressed dump; "
861 				    "decompress using savecore -f %s\n",
862 				    tgt_argv[0]);
863 				terminate(0);
864 			}
865 		}
866 
867 		/*
868 		 * If the target is unknown or is not the rawfile target, do
869 		 * a gelf_check to determine if the file is an ELF file.  If
870 		 * it is not and the target is unknown, use the rawfile tgt.
871 		 * Otherwise an ELF-based target is needed, so we must abort.
872 		 */
873 		if (mdb_gelf_check(io, &ehdr, ET_NONE) == -1) {
874 			if (tgt_ctor != NULL) {
875 				(void) mdb_gelf_check(io, &ehdr, ET_EXEC);
876 				mdb_io_destroy(io);
877 				terminate(1);
878 			} else
879 				tgt_ctor = mdb_rawfile_tgt_create;
880 		}
881 
882 		mdb_io_destroy(io);
883 
884 		if (identify_xvm_file(tgt_argv[0], &longmode) == 1) {
885 #ifdef _LP64
886 			if (!longmode)
887 				goto reexec;
888 #else
889 			if (longmode)
890 				goto reexec;
891 #endif
892 			tgt_ctor = mdb_kvm_tgt_create;
893 			goto tcreate;
894 		}
895 
896 		/*
897 		 * The object file turned out to be a user core file (ET_CORE),
898 		 * and no other arguments were specified, swap 0 and 1.  The
899 		 * proc target will infer the executable for us.
900 		 */
901 		if (ehdr.e_type == ET_CORE) {
902 			tgt_argv[tgt_argc++] = tgt_argv[0];
903 			tgt_argv[0] = NULL;
904 			tgt_ctor = mdb_proc_tgt_create;
905 		}
906 
907 		/*
908 		 * If tgt_argv[1] is filled in, open it up and determine if it
909 		 * is a vmcore file.  If it is, gelf_check will fail and we
910 		 * set tgt_ctor to 'kvm'; otherwise we use the default.
911 		 */
912 		if (tgt_argc > 1 && strcmp(tgt_argv[1], "-") != 0 &&
913 		    tgt_argv[0] != NULL && pidarg == NULL) {
914 			Elf32_Ehdr chdr;
915 
916 			if (access(tgt_argv[1], F_OK) == -1)
917 				die("failed to access %s", tgt_argv[1]);
918 
919 			/* *.N case: drop vmdump.N from the list */
920 			if (tgt_argc == 3) {
921 				if ((io = mdb_fdio_create_path(NULL,
922 				    tgt_argv[2], O_RDONLY, 0)) == NULL)
923 					die("failed to open %s", tgt_argv[2]);
924 				if (mdb_kvm_is_compressed_dump(io))
925 					tgt_argv[--tgt_argc] = NULL;
926 				mdb_io_destroy(io);
927 			}
928 
929 			if ((io = mdb_fdio_create_path(NULL, tgt_argv[1],
930 			    O_RDONLY, 0)) == NULL)
931 				die("failed to open %s", tgt_argv[1]);
932 
933 			if (mdb_gelf_check(io, &chdr, ET_NONE) == -1)
934 				tgt_ctor = mdb_kvm_tgt_create;
935 
936 			mdb_io_destroy(io);
937 		}
938 
939 		/*
940 		 * At this point, we've read the ELF header for either an
941 		 * object file or core into ehdr.  If the class does not match
942 		 * ours, attempt to exec the mdb of the appropriate class.
943 		 */
944 #ifdef _LP64
945 		if (ehdr.e_ident[EI_CLASS] == ELFCLASS32)
946 			goto reexec;
947 #else
948 		if (ehdr.e_ident[EI_CLASS] == ELFCLASS64)
949 			goto reexec;
950 #endif
951 	}
952 
953 tcreate:
954 	if (tgt_ctor == NULL)
955 		tgt_ctor = mdb_proc_tgt_create;
956 
957 	tgt = mdb_tgt_create(tgt_ctor, mdb.m_tgtflags, tgt_argc, tgt_argv);
958 
959 	if (tgt == NULL) {
960 		if (errno == EINVAL)
961 			usage(2); /* target can return EINVAL to get usage */
962 		if (errno == EMDB_TGT)
963 			terminate(1); /* target already printed error msg */
964 		die("failed to initialize target");
965 	}
966 
967 	mdb_tgt_activate(tgt);
968 
969 	mdb_create_loadable_disasms();
970 
971 	if (Vflag != NULL && mdb_dis_select(Vflag) == -1)
972 		warn("invalid disassembler mode -- %s\n", Vflag);
973 
974 
975 	if (Rflag && mdb.m_term != NULL)
976 		warn("Using proto area %s\n", mdb.m_root);
977 
978 	/*
979 	 * If the target was successfully constructed and -O was specified,
980 	 * we now attempt to enter piggy-mode for debugging jurassic problems.
981 	 */
982 	if (Oflag) {
983 		pcinfo_t pci;
984 
985 		(void) strcpy(pci.pc_clname, "RT");
986 
987 		if (priocntl(P_LWPID, P_MYID, PC_GETCID, (caddr_t)&pci) != -1) {
988 			pcparms_t pcp;
989 			rtparms_t *rtp = (rtparms_t *)pcp.pc_clparms;
990 
991 			rtp->rt_pri = 35;
992 			rtp->rt_tqsecs = 0;
993 			rtp->rt_tqnsecs = RT_TQDEF;
994 
995 			pcp.pc_cid = pci.pc_cid;
996 
997 			if (priocntl(P_LWPID, P_MYID, PC_SETPARMS,
998 			    (caddr_t)&pcp) == -1) {
999 				warn("failed to set RT parameters");
1000 				Oflag = 0;
1001 			}
1002 		} else {
1003 			warn("failed to get RT class id");
1004 			Oflag = 0;
1005 		}
1006 
1007 		if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1) {
1008 			warn("failed to lock address space");
1009 			Oflag = 0;
1010 		}
1011 
1012 		if (Oflag)
1013 			mdb_printf("%s: oink, oink!\n", mdb.m_pname);
1014 	}
1015 
1016 	/*
1017 	 * Path evaluation part 2: Re-evaluate the path now that the target
1018 	 * is ready (and thus we have access to the real platform string).
1019 	 * Do this before reading ~/.mdbrc to allow path modifications prior
1020 	 * to performing module auto-loading.
1021 	 */
1022 	mdb_set_ipath(mdb.m_ipathstr);
1023 	mdb_set_lpath(mdb.m_lpathstr);
1024 
1025 	if (!Sflag && (p = getenv("HOME")) != NULL) {
1026 		char rcpath[MAXPATHLEN];
1027 		mdb_io_t *rc_io;
1028 		int fd;
1029 
1030 		(void) mdb_iob_snprintf(rcpath, MAXPATHLEN, "%s/.mdbrc", p);
1031 		fd = open64(rcpath, O_RDONLY);
1032 
1033 		if (fd >= 0 && (rc_io = mdb_fdio_create_named(fd, rcpath))) {
1034 			mdb_iob_t *iob = mdb_iob_create(rc_io, MDB_IOB_RDONLY);
1035 			mdb_iob_t *old = mdb.m_in;
1036 
1037 			mdb.m_in = iob;
1038 			(void) mdb_run();
1039 			mdb.m_in = old;
1040 		}
1041 	}
1042 
1043 	if (!(mdb.m_flags & MDB_FL_NOMODS))
1044 		mdb_module_load_all(0);
1045 
1046 	(void) mdb_signal_sethandler(SIGINT, int_handler, NULL);
1047 	while ((status = mdb_run()) == MDB_ERR_ABORT ||
1048 	    status == MDB_ERR_OUTPUT) {
1049 		/*
1050 		 * If a write failed on stdout, give up.  A more informative
1051 		 * error message will already have been printed by mdb_run().
1052 		 */
1053 		if (status == MDB_ERR_OUTPUT &&
1054 		    mdb_iob_getflags(mdb.m_out) & MDB_IOB_ERR) {
1055 			mdb_warn("write to stdout failed, exiting\n");
1056 			break;
1057 		}
1058 		continue;
1059 	}
1060 
1061 	terminate((status == MDB_ERR_QUIT || status == 0) ? 0 : 1);
1062 	/*NOTREACHED*/
1063 	return (0);
1064 
1065 reexec:
1066 	if ((p = strrchr(execname, '/')) == NULL)
1067 		die("cannot determine absolute pathname\n");
1068 #ifdef _LP64
1069 #ifdef __sparc
1070 	(void) strcpy(p, "/../sparcv7/");
1071 #else
1072 	(void) strcpy(p, "/../i86/");
1073 #endif
1074 #else
1075 #ifdef __sparc
1076 	(void) strcpy(p, "/../sparcv9/");
1077 #else
1078 	(void) strcpy(p, "/../amd64/");
1079 #endif
1080 #endif
1081 	(void) strcat(p, mdb.m_pname);
1082 
1083 	if (mdb.m_term != NULL)
1084 		(void) IOP_CTL(in_io, TCSETSW, &tios);
1085 
1086 	(void) putenv("_MDB_EXEC=1");
1087 	(void) execv(execname, argv);
1088 
1089 	/*
1090 	 * If execv fails, suppress ENOEXEC.  Experience shows the most common
1091 	 * reason is that the machine is booted under a 32-bit kernel, in which
1092 	 * case it is clearer to only print the message below.
1093 	 */
1094 	if (errno != ENOEXEC)
1095 		warn("failed to exec %s", execname);
1096 #ifdef _LP64
1097 	die("64-bit %s cannot debug 32-bit program %s\n",
1098 	    mdb.m_pname, tgt_argv[0] ?
1099 	    tgt_argv[0] : tgt_argv[1]);
1100 #else
1101 	die("32-bit %s cannot debug 64-bit program %s\n",
1102 	    mdb.m_pname, tgt_argv[0] ?
1103 	    tgt_argv[0] : tgt_argv[1]);
1104 #endif
1105 
1106 	goto tcreate;
1107 }
1108