xref: /netbsd-src/sys/kern/sys_process.c (revision ce099b40997c43048fb78bd578195f81d2456523)
1 /*	$NetBSD: sys_process.c,v 1.139 2008/04/28 20:24:04 martin Exp $	*/
2 
3 /*-
4  * Copyright (c) 2008 The NetBSD Foundation, Inc.
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  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26  * POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 /*-
30  * Copyright (c) 1982, 1986, 1989, 1993
31  *	The Regents of the University of California.  All rights reserved.
32  * (c) UNIX System Laboratories, Inc.
33  * All or some portions of this file are derived from material licensed
34  * to the University of California by American Telephone and Telegraph
35  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
36  * the permission of UNIX System Laboratories, Inc.
37  *
38  * This code is derived from software contributed to Berkeley by
39  * Jan-Simon Pendry.
40  *
41  * Redistribution and use in source and binary forms, with or without
42  * modification, are permitted provided that the following conditions
43  * are met:
44  * 1. Redistributions of source code must retain the above copyright
45  *    notice, this list of conditions and the following disclaimer.
46  * 2. Redistributions in binary form must reproduce the above copyright
47  *    notice, this list of conditions and the following disclaimer in the
48  *    documentation and/or other materials provided with the distribution.
49  * 3. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  *
65  *	from: @(#)sys_process.c	8.1 (Berkeley) 6/10/93
66  */
67 
68 /*-
69  * Copyright (c) 1993 Jan-Simon Pendry.
70  * Copyright (c) 1994 Christopher G. Demetriou.  All rights reserved.
71  *
72  * This code is derived from software contributed to Berkeley by
73  * Jan-Simon Pendry.
74  *
75  * Redistribution and use in source and binary forms, with or without
76  * modification, are permitted provided that the following conditions
77  * are met:
78  * 1. Redistributions of source code must retain the above copyright
79  *    notice, this list of conditions and the following disclaimer.
80  * 2. Redistributions in binary form must reproduce the above copyright
81  *    notice, this list of conditions and the following disclaimer in the
82  *    documentation and/or other materials provided with the distribution.
83  * 3. All advertising materials mentioning features or use of this software
84  *    must display the following acknowledgement:
85  *	This product includes software developed by the University of
86  *	California, Berkeley and its contributors.
87  * 4. Neither the name of the University nor the names of its contributors
88  *    may be used to endorse or promote products derived from this software
89  *    without specific prior written permission.
90  *
91  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
92  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
94  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
95  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
96  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
97  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
98  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
99  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
100  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
101  * SUCH DAMAGE.
102  *
103  *	from: @(#)sys_process.c	8.1 (Berkeley) 6/10/93
104  */
105 
106 /*
107  * References:
108  *	(1) Bach's "The Design of the UNIX Operating System",
109  *	(2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution,
110  *	(3) the "4.4BSD Programmer's Reference Manual" published
111  *		by USENIX and O'Reilly & Associates.
112  * The 4.4BSD PRM does a reasonably good job of documenting what the various
113  * ptrace() requests should actually do, and its text is quoted several times
114  * in this file.
115  */
116 
117 #include <sys/cdefs.h>
118 __KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.139 2008/04/28 20:24:04 martin Exp $");
119 
120 #include "opt_coredump.h"
121 #include "opt_ptrace.h"
122 #include "opt_ktrace.h"
123 
124 #include <sys/param.h>
125 #include <sys/systm.h>
126 #include <sys/proc.h>
127 #include <sys/errno.h>
128 #include <sys/ptrace.h>
129 #include <sys/uio.h>
130 #include <sys/user.h>
131 #include <sys/ras.h>
132 #include <sys/malloc.h>
133 #include <sys/kauth.h>
134 #include <sys/mount.h>
135 #include <sys/syscallargs.h>
136 
137 #include <uvm/uvm_extern.h>
138 
139 #include <machine/reg.h>
140 
141 #ifdef PTRACE
142 /*
143  * Process debugging system call.
144  */
145 int
146 sys_ptrace(struct lwp *l, const struct sys_ptrace_args *uap, register_t *retval)
147 {
148 	/* {
149 		syscallarg(int) req;
150 		syscallarg(pid_t) pid;
151 		syscallarg(void *) addr;
152 		syscallarg(int) data;
153 	} */
154 	struct proc *p = l->l_proc;
155 	struct lwp *lt;
156 	struct proc *t;				/* target process */
157 	struct uio uio;
158 	struct iovec iov;
159 	struct ptrace_io_desc piod;
160 	struct ptrace_lwpinfo pl;
161 	struct vmspace *vm;
162 	int error, write, tmp, req, pheld;
163 	int signo;
164 	ksiginfo_t ksi;
165 #ifdef COREDUMP
166 	char *path;
167 #endif
168 
169 	error = 0;
170 	req = SCARG(uap, req);
171 
172 	/*
173 	 * If attaching or detaching, we need to get a write hold on the
174 	 * proclist lock so that we can re-parent the target process.
175 	 */
176 	mutex_enter(proc_lock);
177 
178 	/* "A foolish consistency..." XXX */
179 	if (req == PT_TRACE_ME) {
180 		t = p;
181 		mutex_enter(t->p_lock);
182 	} else {
183 		/* Find the process we're supposed to be operating on. */
184 		if ((t = p_find(SCARG(uap, pid), PFIND_LOCKED)) == NULL) {
185 			mutex_exit(proc_lock);
186 			return (ESRCH);
187 		}
188 
189 		/* XXX-elad */
190 		mutex_enter(t->p_lock);
191 		error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_CANSEE,
192 		    t, KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_ENTRY), NULL, NULL);
193 		if (error) {
194 			mutex_exit(proc_lock);
195 			mutex_exit(t->p_lock);
196 			return (ESRCH);
197 		}
198 	}
199 
200 	/*
201 	 * Grab a reference on the process to prevent it from execing or
202 	 * exiting.
203 	 */
204 	if (!rw_tryenter(&t->p_reflock, RW_READER)) {
205 		mutex_exit(proc_lock);
206 		mutex_exit(t->p_lock);
207 		return EBUSY;
208 	}
209 
210 	/* Make sure we can operate on it. */
211 	switch (req) {
212 	case  PT_TRACE_ME:
213 		/* Saying that you're being traced is always legal. */
214 		break;
215 
216 	case  PT_ATTACH:
217 		/*
218 		 * You can't attach to a process if:
219 		 *	(1) it's the process that's doing the attaching,
220 		 */
221 		if (t->p_pid == p->p_pid) {
222 			error = EINVAL;
223 			break;
224 		}
225 
226 		/*
227 		 *  (2) it's a system process
228 		 */
229 		if (t->p_flag & PK_SYSTEM) {
230 			error = EPERM;
231 			break;
232 		}
233 
234 		/*
235 		 *	(3) it's already being traced, or
236 		 */
237 		if (ISSET(t->p_slflag, PSL_TRACED)) {
238 			error = EBUSY;
239 			break;
240 		}
241 
242 		/*
243 		 * 	(4) the tracer is chrooted, and its root directory is
244 		 * 	    not at or above the root directory of the tracee
245 		 */
246 		mutex_exit(t->p_lock);	/* XXXSMP */
247 		tmp = proc_isunder(t, l);
248 		mutex_enter(t->p_lock);	/* XXXSMP */
249 		if (!tmp) {
250 			error = EPERM;
251 			break;
252 		}
253 		break;
254 
255 	case  PT_READ_I:
256 	case  PT_READ_D:
257 	case  PT_WRITE_I:
258 	case  PT_WRITE_D:
259 	case  PT_IO:
260 #ifdef PT_GETREGS
261 	case  PT_GETREGS:
262 #endif
263 #ifdef PT_SETREGS
264 	case  PT_SETREGS:
265 #endif
266 #ifdef PT_GETFPREGS
267 	case  PT_GETFPREGS:
268 #endif
269 #ifdef PT_SETFPREGS
270 	case  PT_SETFPREGS:
271 #endif
272 #ifdef __HAVE_PTRACE_MACHDEP
273 	PTRACE_MACHDEP_REQUEST_CASES
274 #endif
275 		/*
276 		 * You can't read/write the memory or registers of a process
277 		 * if the tracer is chrooted, and its root directory is not at
278 		 * or above the root directory of the tracee.
279 		 */
280 		mutex_exit(t->p_lock);	/* XXXSMP */
281 		tmp = proc_isunder(t, l);
282 		mutex_enter(t->p_lock);	/* XXXSMP */
283 		if (!tmp) {
284 			error = EPERM;
285 			break;
286 		}
287 		/*FALLTHROUGH*/
288 
289 	case  PT_CONTINUE:
290 	case  PT_KILL:
291 	case  PT_DETACH:
292 	case  PT_LWPINFO:
293 	case  PT_SYSCALL:
294 #ifdef COREDUMP
295 	case  PT_DUMPCORE:
296 #endif
297 #ifdef PT_STEP
298 	case  PT_STEP:
299 #endif
300 		/*
301 		 * You can't do what you want to the process if:
302 		 *	(1) It's not being traced at all,
303 		 */
304 		if (!ISSET(t->p_slflag, PSL_TRACED)) {
305 			error = EPERM;
306 			break;
307 		}
308 
309 		/*
310 		 *	(2) it's being traced by procfs (which has
311 		 *	    different signal delivery semantics),
312 		 */
313 		if (ISSET(t->p_slflag, PSL_FSTRACE)) {
314 			uprintf("file system traced\n");
315 			error = EBUSY;
316 			break;
317 		}
318 
319 		/*
320 		 *	(3) it's not being traced by _you_, or
321 		 */
322 		if (t->p_pptr != p) {
323 			uprintf("parent %d != %d\n", t->p_pptr->p_pid, p->p_pid);
324 			error = EBUSY;
325 			break;
326 		}
327 
328 		/*
329 		 *	(4) it's not currently stopped.
330 		 */
331 		if (t->p_stat != SSTOP || !t->p_waited /* XXXSMP */) {
332 			uprintf("stat %d flag %d\n", t->p_stat,
333 			    !t->p_waited);
334 			error = EBUSY;
335 			break;
336 		}
337 		break;
338 
339 	default:			/* It was not a legal request. */
340 		error = EINVAL;
341 		break;
342 	}
343 
344 	if (error == 0)
345 		error = kauth_authorize_process(l->l_cred,
346 		    KAUTH_PROCESS_PTRACE, t, KAUTH_ARG(req),
347 		    NULL, NULL);
348 
349 	if (error != 0) {
350 		mutex_exit(proc_lock);
351 		mutex_exit(t->p_lock);
352 		rw_exit(&t->p_reflock);
353 		return error;
354 	}
355 
356 	/* Do single-step fixup if needed. */
357 	FIX_SSTEP(t);
358 
359 	/*
360 	 * XXX NJWLWP
361 	 *
362 	 * The entire ptrace interface needs work to be useful to a
363 	 * process with multiple LWPs. For the moment, we'll kluge
364 	 * this; memory access will be fine, but register access will
365 	 * be weird.
366 	 */
367 	lt = proc_representative_lwp(t, NULL, 1);
368 	lwp_addref(lt);
369 
370 	/*
371 	 * Which locks do we need held? XXX Ugly.
372 	 */
373 	switch (req) {
374 #ifdef PT_STEP
375 	case PT_STEP:
376 #endif
377 	case PT_CONTINUE:
378 	case PT_DETACH:
379 	case PT_KILL:
380 	case PT_SYSCALL:
381 	case PT_ATTACH:
382 	case PT_TRACE_ME:
383 		pheld = 1;
384 		break;
385 	default:
386 		mutex_exit(proc_lock);
387 		mutex_exit(t->p_lock);
388 		pheld = 0;
389 		break;
390 	}
391 
392 	/* Now do the operation. */
393 	write = 0;
394 	*retval = 0;
395 	tmp = 0;
396 
397 	switch (req) {
398 	case  PT_TRACE_ME:
399 		/* Just set the trace flag. */
400 		SET(t->p_slflag, PSL_TRACED);
401 		t->p_opptr = t->p_pptr;
402 		break;
403 
404 	case  PT_WRITE_I:		/* XXX no separate I and D spaces */
405 	case  PT_WRITE_D:
406 #if defined(__HAVE_RAS)
407 		/*
408 		 * Can't write to a RAS
409 		 */
410 		if (ras_lookup(t, SCARG(uap, addr)) != (void *)-1) {
411 			error = EACCES;
412 			break;
413 		}
414 #endif
415 		write = 1;
416 		tmp = SCARG(uap, data);
417 		/* FALLTHROUGH */
418 
419 	case  PT_READ_I:		/* XXX no separate I and D spaces */
420 	case  PT_READ_D:
421 		/* write = 0 done above. */
422 		iov.iov_base = (void *)&tmp;
423 		iov.iov_len = sizeof(tmp);
424 		uio.uio_iov = &iov;
425 		uio.uio_iovcnt = 1;
426 		uio.uio_offset = (off_t)(unsigned long)SCARG(uap, addr);
427 		uio.uio_resid = sizeof(tmp);
428 		uio.uio_rw = write ? UIO_WRITE : UIO_READ;
429 		UIO_SETUP_SYSSPACE(&uio);
430 
431 		error = process_domem(l, lt, &uio);
432 		if (!write)
433 			*retval = tmp;
434 		break;
435 
436 	case  PT_IO:
437 		error = copyin(SCARG(uap, addr), &piod, sizeof(piod));
438 		if (error)
439 			break;
440 		switch (piod.piod_op) {
441 		case PIOD_READ_D:
442 		case PIOD_READ_I:
443 			uio.uio_rw = UIO_READ;
444 			break;
445 		case PIOD_WRITE_D:
446 		case PIOD_WRITE_I:
447 			/*
448 			 * Can't write to a RAS
449 			 */
450 			if (ras_lookup(t, SCARG(uap, addr)) != (void *)-1) {
451 				return (EACCES);
452 			}
453 			uio.uio_rw = UIO_WRITE;
454 			break;
455 		default:
456 			error = EINVAL;
457 			break;
458 		}
459 		if (error)
460 			break;
461 		error = proc_vmspace_getref(l->l_proc, &vm);
462 		if (error)
463 			break;
464 		iov.iov_base = piod.piod_addr;
465 		iov.iov_len = piod.piod_len;
466 		uio.uio_iov = &iov;
467 		uio.uio_iovcnt = 1;
468 		uio.uio_offset = (off_t)(unsigned long)piod.piod_offs;
469 		uio.uio_resid = piod.piod_len;
470 		uio.uio_vmspace = vm;
471 
472 		error = process_domem(l, lt, &uio);
473 		piod.piod_len -= uio.uio_resid;
474 		(void) copyout(&piod, SCARG(uap, addr), sizeof(piod));
475 		uvmspace_free(vm);
476 		break;
477 
478 #ifdef COREDUMP
479 	case  PT_DUMPCORE:
480 		if ((path = SCARG(uap, addr)) != NULL) {
481 			char *dst;
482 			int len = SCARG(uap, data);
483 			if (len < 0 || len >= MAXPATHLEN) {
484 				error = EINVAL;
485 				break;
486 			}
487 			dst = malloc(len + 1, M_TEMP, M_WAITOK);
488 			if ((error = copyin(path, dst, len)) != 0) {
489 				free(dst, M_TEMP);
490 				break;
491 			}
492 			path = dst;
493 			path[len] = '\0';
494 		}
495 		error = coredump(lt, path);
496 		if (path)
497 			free(path, M_TEMP);
498 		break;
499 #endif
500 
501 #ifdef PT_STEP
502 	case  PT_STEP:
503 		/*
504 		 * From the 4.4BSD PRM:
505 		 * "Execution continues as in request PT_CONTINUE; however
506 		 * as soon as possible after execution of at least one
507 		 * instruction, execution stops again. [ ... ]"
508 		 */
509 #endif
510 	case  PT_CONTINUE:
511 	case  PT_SYSCALL:
512 	case  PT_DETACH:
513 		if (req == PT_SYSCALL) {
514 			if (!ISSET(t->p_slflag, PSL_SYSCALL)) {
515 				SET(t->p_slflag, PSL_SYSCALL);
516 #ifdef __HAVE_SYSCALL_INTERN
517 				(*t->p_emul->e_syscall_intern)(t);
518 #endif
519 			}
520 		} else {
521 			if (ISSET(t->p_slflag, PSL_SYSCALL)) {
522 				CLR(t->p_slflag, PSL_SYSCALL);
523 #ifdef __HAVE_SYSCALL_INTERN
524 				(*t->p_emul->e_syscall_intern)(t);
525 #endif
526 			}
527 		}
528 		p->p_trace_enabled = trace_is_enabled(p);
529 
530 		/*
531 		 * From the 4.4BSD PRM:
532 		 * "The data argument is taken as a signal number and the
533 		 * child's execution continues at location addr as if it
534 		 * incurred that signal.  Normally the signal number will
535 		 * be either 0 to indicate that the signal that caused the
536 		 * stop should be ignored, or that value fetched out of
537 		 * the process's image indicating which signal caused
538 		 * the stop.  If addr is (int *)1 then execution continues
539 		 * from where it stopped."
540 		 */
541 
542 		/* Check that the data is a valid signal number or zero. */
543 		if (SCARG(uap, data) < 0 || SCARG(uap, data) >= NSIG) {
544 			error = EINVAL;
545 			break;
546 		}
547 
548 		uvm_lwp_hold(lt);
549 
550 		/* If the address parameter is not (int *)1, set the pc. */
551 		if ((int *)SCARG(uap, addr) != (int *)1)
552 			if ((error = process_set_pc(lt, SCARG(uap, addr))) != 0) {
553 				uvm_lwp_rele(lt);
554 				break;
555 			}
556 
557 #ifdef PT_STEP
558 		/*
559 		 * Arrange for a single-step, if that's requested and possible.
560 		 */
561 		error = process_sstep(lt, req == PT_STEP);
562 		if (error) {
563 			uvm_lwp_rele(lt);
564 			break;
565 		}
566 #endif
567 
568 		uvm_lwp_rele(lt);
569 
570 		if (req == PT_DETACH) {
571 			CLR(t->p_slflag, PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL);
572 
573 			/* give process back to original parent or init */
574 			if (t->p_opptr != t->p_pptr) {
575 				struct proc *pp = t->p_opptr;
576 				proc_reparent(t, pp ? pp : initproc);
577 			}
578 
579 			/* not being traced any more */
580 			t->p_opptr = NULL;
581 		}
582 
583 		signo = SCARG(uap, data);
584 	sendsig:
585 		/* Finally, deliver the requested signal (or none). */
586 		if (t->p_stat == SSTOP) {
587 			/*
588 			 * Unstop the process.  If it needs to take a
589 			 * signal, make all efforts to ensure that at
590 			 * an LWP runs to see it.
591 			 */
592 			t->p_xstat = signo;
593 			proc_unstop(t);
594 		} else if (signo != 0) {
595 			KSI_INIT_EMPTY(&ksi);
596 			ksi.ksi_signo = signo;
597 			kpsignal2(t, &ksi);
598 		}
599 		break;
600 
601 	case  PT_KILL:
602 		/* just send the process a KILL signal. */
603 		signo = SIGKILL;
604 		goto sendsig;	/* in PT_CONTINUE, above. */
605 
606 	case  PT_ATTACH:
607 		/*
608 		 * Go ahead and set the trace flag.
609 		 * Save the old parent (it's reset in
610 		 *   _DETACH, and also in kern_exit.c:wait4()
611 		 * Reparent the process so that the tracing
612 		 *   proc gets to see all the action.
613 		 * Stop the target.
614 		 */
615 		t->p_opptr = t->p_pptr;
616 		if (t->p_pptr != p) {
617 			if (t->p_pptr->p_lock < t->p_lock) {
618 				if (!mutex_tryenter(t->p_pptr->p_lock)) {
619 					mutex_exit(t->p_lock);
620 					mutex_enter(t->p_pptr->p_lock);
621 				}
622 			} else if (t->p_pptr->p_lock > t->p_lock) {
623 				mutex_enter(t->p_pptr->p_lock);
624 			}
625 			t->p_pptr->p_slflag |= PSL_CHTRACED;
626 			proc_reparent(t, p);
627 			if (t->p_pptr->p_lock != t->p_lock)
628 				mutex_exit(t->p_pptr->p_lock);
629 		}
630 		SET(t->p_slflag, PSL_TRACED);
631 		signo = SIGSTOP;
632 		goto sendsig;
633 
634 	case PT_LWPINFO:
635 		if (SCARG(uap, data) != sizeof(pl)) {
636 			error = EINVAL;
637 			break;
638 		}
639 		error = copyin(SCARG(uap, addr), &pl, sizeof(pl));
640 		if (error)
641 			break;
642 		tmp = pl.pl_lwpid;
643 		lwp_delref(lt);
644 		mutex_enter(t->p_lock);
645 		if (tmp == 0)
646 			lt = LIST_FIRST(&t->p_lwps);
647 		else {
648 			lt = lwp_find(p, tmp);
649 			if (lt == NULL) {
650 				mutex_exit(t->p_lock);
651 				error = ESRCH;
652 				break;
653 			}
654 			lt = LIST_NEXT(lt, l_sibling);
655 		}
656 		while (lt != NULL && lt->l_stat == LSZOMB)
657 			lt = LIST_NEXT(lt, l_sibling);
658 		pl.pl_lwpid = 0;
659 		pl.pl_event = 0;
660 		if (lt) {
661 			lwp_addref(lt);
662 			pl.pl_lwpid = lt->l_lid;
663 			if (lt->l_lid == t->p_sigctx.ps_lwp)
664 				pl.pl_event = PL_EVENT_SIGNAL;
665 		}
666 		mutex_exit(t->p_lock);
667 
668 		error = copyout(&pl, SCARG(uap, addr), sizeof(pl));
669 		break;
670 
671 #ifdef PT_SETREGS
672 	case  PT_SETREGS:
673 		write = 1;
674 #endif
675 #ifdef PT_GETREGS
676 	case  PT_GETREGS:
677 		/* write = 0 done above. */
678 #endif
679 #if defined(PT_SETREGS) || defined(PT_GETREGS)
680 		tmp = SCARG(uap, data);
681 		if (tmp != 0 && t->p_nlwps > 1) {
682 			lwp_delref(lt);
683 			mutex_enter(t->p_lock);
684 			lt = lwp_find(t, tmp);
685 			if (lt == NULL) {
686 				mutex_exit(t->p_lock);
687 				error = ESRCH;
688 				break;
689 			}
690 			lwp_addref(lt);
691 			mutex_exit(t->p_lock);
692 		}
693 		if (!process_validregs(lt))
694 			error = EINVAL;
695 		else {
696 			error = proc_vmspace_getref(l->l_proc, &vm);
697 			if (error)
698 				break;
699 			iov.iov_base = SCARG(uap, addr);
700 			iov.iov_len = sizeof(struct reg);
701 			uio.uio_iov = &iov;
702 			uio.uio_iovcnt = 1;
703 			uio.uio_offset = 0;
704 			uio.uio_resid = sizeof(struct reg);
705 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
706 			uio.uio_vmspace = vm;
707 
708 			error = process_doregs(l, lt, &uio);
709 			uvmspace_free(vm);
710 		}
711 		break;
712 #endif
713 
714 #ifdef PT_SETFPREGS
715 	case  PT_SETFPREGS:
716 		write = 1;
717 #endif
718 #ifdef PT_GETFPREGS
719 	case  PT_GETFPREGS:
720 		/* write = 0 done above. */
721 #endif
722 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
723 		tmp = SCARG(uap, data);
724 		if (tmp != 0 && t->p_nlwps > 1) {
725 			lwp_delref(lt);
726 			mutex_enter(t->p_lock);
727 			lt = lwp_find(t, tmp);
728 			if (lt == NULL) {
729 				mutex_exit(t->p_lock);
730 				error = ESRCH;
731 				break;
732 			}
733 			lwp_addref(lt);
734 			mutex_exit(t->p_lock);
735 		}
736 		if (!process_validfpregs(lt))
737 			error = EINVAL;
738 		else {
739 			error = proc_vmspace_getref(l->l_proc, &vm);
740 			if (error)
741 				break;
742 			iov.iov_base = SCARG(uap, addr);
743 			iov.iov_len = sizeof(struct fpreg);
744 			uio.uio_iov = &iov;
745 			uio.uio_iovcnt = 1;
746 			uio.uio_offset = 0;
747 			uio.uio_resid = sizeof(struct fpreg);
748 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
749 			uio.uio_vmspace = vm;
750 
751 			error = process_dofpregs(l, lt, &uio);
752 			uvmspace_free(vm);
753 		}
754 		break;
755 #endif
756 
757 #ifdef __HAVE_PTRACE_MACHDEP
758 	PTRACE_MACHDEP_REQUEST_CASES
759 		error = ptrace_machdep_dorequest(l, lt,
760 		    req, SCARG(uap, addr), SCARG(uap, data));
761 		break;
762 #endif
763 	}
764 
765 	if (pheld) {
766 		mutex_exit(t->p_lock);
767 		mutex_exit(proc_lock);
768 	}
769 	if (lt != NULL)
770 		lwp_delref(lt);
771 	rw_exit(&t->p_reflock);
772 
773 	return error;
774 }
775 
776 int
777 process_doregs(struct lwp *curl /*tracer*/,
778     struct lwp *l /*traced*/,
779     struct uio *uio)
780 {
781 #if defined(PT_GETREGS) || defined(PT_SETREGS)
782 	int error;
783 	struct reg r;
784 	char *kv;
785 	int kl;
786 
787 	if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r))
788 		return EINVAL;
789 
790 	kl = sizeof(r);
791 	kv = (char *)&r;
792 
793 	kv += uio->uio_offset;
794 	kl -= uio->uio_offset;
795 	if ((size_t)kl > uio->uio_resid)
796 		kl = uio->uio_resid;
797 
798 	uvm_lwp_hold(l);
799 
800 	error = process_read_regs(l, &r);
801 	if (error == 0)
802 		error = uiomove(kv, kl, uio);
803 	if (error == 0 && uio->uio_rw == UIO_WRITE) {
804 		if (l->l_stat != LSSTOP)
805 			error = EBUSY;
806 		else
807 			error = process_write_regs(l, &r);
808 	}
809 
810 	uvm_lwp_rele(l);
811 
812 	uio->uio_offset = 0;
813 	return (error);
814 #else
815 	return (EINVAL);
816 #endif
817 }
818 
819 int
820 process_validregs(struct lwp *l)
821 {
822 
823 #if defined(PT_SETREGS) || defined(PT_GETREGS)
824 	return ((l->l_flag & LW_SYSTEM) == 0);
825 #else
826 	return (0);
827 #endif
828 }
829 
830 int
831 process_dofpregs(struct lwp *curl /*tracer*/,
832     struct lwp *l /*traced*/,
833     struct uio *uio)
834 {
835 #if defined(PT_GETFPREGS) || defined(PT_SETFPREGS)
836 	int error;
837 	struct fpreg r;
838 	char *kv;
839 	int kl;
840 
841 	if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r))
842 		return EINVAL;
843 
844 	kl = sizeof(r);
845 	kv = (char *)&r;
846 
847 	kv += uio->uio_offset;
848 	kl -= uio->uio_offset;
849 	if ((size_t)kl > uio->uio_resid)
850 		kl = uio->uio_resid;
851 
852 	uvm_lwp_hold(l);
853 
854 	error = process_read_fpregs(l, &r);
855 	if (error == 0)
856 		error = uiomove(kv, kl, uio);
857 	if (error == 0 && uio->uio_rw == UIO_WRITE) {
858 		if (l->l_stat != LSSTOP)
859 			error = EBUSY;
860 		else
861 			error = process_write_fpregs(l, &r);
862 	}
863 
864 	uvm_lwp_rele(l);
865 
866 	uio->uio_offset = 0;
867 	return (error);
868 #else
869 	return (EINVAL);
870 #endif
871 }
872 
873 int
874 process_validfpregs(struct lwp *l)
875 {
876 
877 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
878 	return ((l->l_flag & LW_SYSTEM) == 0);
879 #else
880 	return (0);
881 #endif
882 }
883 #endif /* PTRACE */
884 
885 #if defined(KTRACE) || defined(PTRACE)
886 int
887 process_domem(struct lwp *curl /*tracer*/,
888     struct lwp *l /*traced*/,
889     struct uio *uio)
890 {
891 	struct proc *p = l->l_proc;	/* traced */
892 	struct vmspace *vm;
893 	int error;
894 
895 	size_t len;
896 #ifdef PMAP_NEED_PROCWR
897 	vaddr_t	addr;
898 #endif
899 
900 	error = 0;
901 	len = uio->uio_resid;
902 
903 	if (len == 0)
904 		return (0);
905 
906 #ifdef PMAP_NEED_PROCWR
907 	addr = uio->uio_offset;
908 #endif
909 
910 	vm = p->p_vmspace;
911 
912 	mutex_enter(&vm->vm_map.misc_lock);
913 	if ((l->l_flag & LW_WEXIT) || vm->vm_refcnt < 1)
914 		error = EFAULT;
915 	if (error == 0)
916 		p->p_vmspace->vm_refcnt++;  /* XXX */
917 	mutex_exit(&vm->vm_map.misc_lock);
918 	if (error != 0)
919 		return (error);
920 	error = uvm_io(&vm->vm_map, uio);
921 	uvmspace_free(vm);
922 
923 #ifdef PMAP_NEED_PROCWR
924 	if (error == 0 && uio->uio_rw == UIO_WRITE)
925 		pmap_procwr(p, addr, len);
926 #endif
927 	return (error);
928 }
929 #endif /* KTRACE || PTRACE */
930 
931 #if defined(KTRACE) || defined(PTRACE)
932 void
933 process_stoptrace(void)
934 {
935 	struct lwp *l = curlwp;
936 	struct proc *p = l->l_proc, *pp;
937 
938 	mutex_enter(proc_lock);
939 	mutex_enter(p->p_lock);
940 	pp = p->p_pptr;
941 	if (pp->p_pid == 1) {
942 		CLR(p->p_slflag, PSL_SYSCALL);	/* XXXSMP */
943 		mutex_exit(p->p_lock);
944 		mutex_exit(proc_lock);
945 		return;
946 	}
947 
948 	p->p_xstat = SIGTRAP;
949 	proc_stop(p, 1, SIGSTOP);
950 	mutex_exit(proc_lock);
951 
952 	/*
953 	 * Call issignal() once only, to have it take care of the
954 	 * pending stop.  Signal processing will take place as usual
955 	 * from userret().
956 	 */
957 	KERNEL_UNLOCK_ALL(l, &l->l_biglocks);
958 	(void)issignal(l);
959 	mutex_exit(p->p_lock);
960 	KERNEL_LOCK(l->l_biglocks - 1, l);
961 }
962 #endif	/* KTRACE || PTRACE */
963