xref: /netbsd-src/sys/kern/sys_process.c (revision da39824b722dbd84beb9a1ab7e8de6710cc44d4b)
1 /*	$NetBSD: sys_process.c,v 1.163 2014/01/04 00:10:03 dsl Exp $	*/
2 
3 /*-
4  * Copyright (c) 2008, 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 /*-
33  * Copyright (c) 1982, 1986, 1989, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  * (c) UNIX System Laboratories, Inc.
36  * All or some portions of this file are derived from material licensed
37  * to the University of California by American Telephone and Telegraph
38  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
39  * the permission of UNIX System Laboratories, Inc.
40  *
41  * This code is derived from software contributed to Berkeley by
42  * Jan-Simon Pendry.
43  *
44  * Redistribution and use in source and binary forms, with or without
45  * modification, are permitted provided that the following conditions
46  * are met:
47  * 1. Redistributions of source code must retain the above copyright
48  *    notice, this list of conditions and the following disclaimer.
49  * 2. Redistributions in binary form must reproduce the above copyright
50  *    notice, this list of conditions and the following disclaimer in the
51  *    documentation and/or other materials provided with the distribution.
52  * 3. Neither the name of the University nor the names of its contributors
53  *    may be used to endorse or promote products derived from this software
54  *    without specific prior written permission.
55  *
56  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
57  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
58  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
59  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
60  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
61  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
62  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
63  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
64  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
65  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
66  * SUCH DAMAGE.
67  *
68  *	from: @(#)sys_process.c	8.1 (Berkeley) 6/10/93
69  */
70 
71 /*-
72  * Copyright (c) 1993 Jan-Simon Pendry.
73  * Copyright (c) 1994 Christopher G. Demetriou.  All rights reserved.
74  *
75  * This code is derived from software contributed to Berkeley by
76  * Jan-Simon Pendry.
77  *
78  * Redistribution and use in source and binary forms, with or without
79  * modification, are permitted provided that the following conditions
80  * are met:
81  * 1. Redistributions of source code must retain the above copyright
82  *    notice, this list of conditions and the following disclaimer.
83  * 2. Redistributions in binary form must reproduce the above copyright
84  *    notice, this list of conditions and the following disclaimer in the
85  *    documentation and/or other materials provided with the distribution.
86  * 3. All advertising materials mentioning features or use of this software
87  *    must display the following acknowledgement:
88  *	This product includes software developed by the University of
89  *	California, Berkeley and its contributors.
90  * 4. Neither the name of the University nor the names of its contributors
91  *    may be used to endorse or promote products derived from this software
92  *    without specific prior written permission.
93  *
94  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
95  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
96  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
97  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
98  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
99  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
100  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
101  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
102  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
103  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
104  * SUCH DAMAGE.
105  *
106  *	from: @(#)sys_process.c	8.1 (Berkeley) 6/10/93
107  */
108 
109 /*
110  * References:
111  *	(1) Bach's "The Design of the UNIX Operating System",
112  *	(2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution,
113  *	(3) the "4.4BSD Programmer's Reference Manual" published
114  *		by USENIX and O'Reilly & Associates.
115  * The 4.4BSD PRM does a reasonably good job of documenting what the various
116  * ptrace() requests should actually do, and its text is quoted several times
117  * in this file.
118  */
119 
120 #include <sys/cdefs.h>
121 __KERNEL_RCSID(0, "$NetBSD: sys_process.c,v 1.163 2014/01/04 00:10:03 dsl Exp $");
122 
123 #include "opt_ptrace.h"
124 #include "opt_ktrace.h"
125 
126 #include <sys/param.h>
127 #include <sys/systm.h>
128 #include <sys/proc.h>
129 #include <sys/errno.h>
130 #include <sys/ptrace.h>
131 #include <sys/uio.h>
132 #include <sys/ras.h>
133 #include <sys/kmem.h>
134 #include <sys/kauth.h>
135 #include <sys/mount.h>
136 #include <sys/syscallargs.h>
137 
138 #include <uvm/uvm_extern.h>
139 
140 #include <machine/reg.h>
141 
142 #ifdef PTRACE
143 static kauth_listener_t ptrace_listener;
144 
145 static int
146 ptrace_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie,
147     void *arg0, void *arg1, void *arg2, void *arg3)
148 {
149 	struct proc *p;
150 	int result;
151 
152 	result = KAUTH_RESULT_DEFER;
153 	p = arg0;
154 
155 	if (action != KAUTH_PROCESS_PTRACE)
156 		return result;
157 
158 	switch ((u_long)arg1) {
159 	case PT_TRACE_ME:
160 	case PT_ATTACH:
161 	case PT_WRITE_I:
162 	case PT_WRITE_D:
163 	case PT_READ_I:
164 	case PT_READ_D:
165 	case PT_IO:
166 #ifdef PT_GETREGS
167 	case PT_GETREGS:
168 #endif
169 #ifdef PT_SETREGS
170 	case PT_SETREGS:
171 #endif
172 #ifdef PT_GETFPREGS
173 	case PT_GETFPREGS:
174 #endif
175 #ifdef PT_SETFPREGS
176 	case PT_SETFPREGS:
177 #endif
178 	case PT_SET_EVENT_MASK:
179 	case PT_GET_EVENT_MASK:
180 	case PT_GET_PROCESS_STATE:
181 #ifdef __HAVE_PTRACE_MACHDEP
182 	PTRACE_MACHDEP_REQUEST_CASES
183 #endif
184 		if (kauth_cred_getuid(cred) != kauth_cred_getuid(p->p_cred) ||
185 		    ISSET(p->p_flag, PK_SUGID)) {
186 			break;
187 		}
188 
189 		result = KAUTH_RESULT_ALLOW;
190 
191 	break;
192 
193 #ifdef PT_STEP
194 	case PT_STEP:
195 #endif
196 	case PT_CONTINUE:
197 	case PT_KILL:
198 	case PT_DETACH:
199 	case PT_LWPINFO:
200 	case PT_SYSCALL:
201 	case PT_SYSCALLEMU:
202 	case PT_DUMPCORE:
203 		result = KAUTH_RESULT_ALLOW;
204 		break;
205 
206 	default:
207 		break;
208 	}
209 
210 	return result;
211 }
212 
213 void
214 ptrace_init(void)
215 {
216 
217 	ptrace_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS,
218 	    ptrace_listener_cb, NULL);
219 }
220 
221 /*
222  * Process debugging system call.
223  */
224 int
225 sys_ptrace(struct lwp *l, const struct sys_ptrace_args *uap, register_t *retval)
226 {
227 	/* {
228 		syscallarg(int) req;
229 		syscallarg(pid_t) pid;
230 		syscallarg(void *) addr;
231 		syscallarg(int) data;
232 	} */
233 	struct proc *p = l->l_proc;
234 	struct lwp *lt;
235 #ifdef PT_STEP
236 	struct lwp *lt2;
237 #endif
238 	struct proc *t;				/* target process */
239 	struct uio uio;
240 	struct iovec iov;
241 	struct ptrace_io_desc piod;
242 	struct ptrace_event pe;
243 	struct ptrace_state ps;
244 	struct ptrace_lwpinfo pl;
245 	struct vmspace *vm;
246 	int error, write, tmp, req, pheld;
247 	int signo = 0;
248 	int resume_all;
249 	ksiginfo_t ksi;
250 	char *path;
251 	int len = 0;
252 
253 	error = 0;
254 	req = SCARG(uap, req);
255 
256 	/*
257 	 * If attaching or detaching, we need to get a write hold on the
258 	 * proclist lock so that we can re-parent the target process.
259 	 */
260 	mutex_enter(proc_lock);
261 
262 	/* "A foolish consistency..." XXX */
263 	if (req == PT_TRACE_ME) {
264 		t = p;
265 		mutex_enter(t->p_lock);
266 	} else {
267 		/* Find the process we're supposed to be operating on. */
268 		t = proc_find(SCARG(uap, pid));
269 		if (t == NULL) {
270 			mutex_exit(proc_lock);
271 			return (ESRCH);
272 		}
273 
274 		/* XXX-elad */
275 		mutex_enter(t->p_lock);
276 		error = kauth_authorize_process(l->l_cred, KAUTH_PROCESS_CANSEE,
277 		    t, KAUTH_ARG(KAUTH_REQ_PROCESS_CANSEE_ENTRY), NULL, NULL);
278 		if (error) {
279 			mutex_exit(proc_lock);
280 			mutex_exit(t->p_lock);
281 			return (ESRCH);
282 		}
283 	}
284 
285 	/*
286 	 * Grab a reference on the process to prevent it from execing or
287 	 * exiting.
288 	 */
289 	if (!rw_tryenter(&t->p_reflock, RW_READER)) {
290 		mutex_exit(proc_lock);
291 		mutex_exit(t->p_lock);
292 		return EBUSY;
293 	}
294 
295 	/* Make sure we can operate on it. */
296 	switch (req) {
297 	case  PT_TRACE_ME:
298 		/* Saying that you're being traced is always legal. */
299 		break;
300 
301 	case  PT_ATTACH:
302 		/*
303 		 * You can't attach to a process if:
304 		 *	(1) it's the process that's doing the attaching,
305 		 */
306 		if (t->p_pid == p->p_pid) {
307 			error = EINVAL;
308 			break;
309 		}
310 
311 		/*
312 		 *  (2) it's a system process
313 		 */
314 		if (t->p_flag & PK_SYSTEM) {
315 			error = EPERM;
316 			break;
317 		}
318 
319 		/*
320 		 *	(3) it's already being traced, or
321 		 */
322 		if (ISSET(t->p_slflag, PSL_TRACED)) {
323 			error = EBUSY;
324 			break;
325 		}
326 
327 		/*
328 		 * 	(4) the tracer is chrooted, and its root directory is
329 		 * 	    not at or above the root directory of the tracee
330 		 */
331 		mutex_exit(t->p_lock);	/* XXXSMP */
332 		tmp = proc_isunder(t, l);
333 		mutex_enter(t->p_lock);	/* XXXSMP */
334 		if (!tmp) {
335 			error = EPERM;
336 			break;
337 		}
338 		break;
339 
340 	case  PT_READ_I:
341 	case  PT_READ_D:
342 	case  PT_WRITE_I:
343 	case  PT_WRITE_D:
344 	case  PT_IO:
345 #ifdef PT_GETREGS
346 	case  PT_GETREGS:
347 #endif
348 #ifdef PT_SETREGS
349 	case  PT_SETREGS:
350 #endif
351 #ifdef PT_GETFPREGS
352 	case  PT_GETFPREGS:
353 #endif
354 #ifdef PT_SETFPREGS
355 	case  PT_SETFPREGS:
356 #endif
357 #ifdef __HAVE_PTRACE_MACHDEP
358 	PTRACE_MACHDEP_REQUEST_CASES
359 #endif
360 		/*
361 		 * You can't read/write the memory or registers of a process
362 		 * if the tracer is chrooted, and its root directory is not at
363 		 * or above the root directory of the tracee.
364 		 */
365 		mutex_exit(t->p_lock);	/* XXXSMP */
366 		tmp = proc_isunder(t, l);
367 		mutex_enter(t->p_lock);	/* XXXSMP */
368 		if (!tmp) {
369 			error = EPERM;
370 			break;
371 		}
372 		/*FALLTHROUGH*/
373 
374 	case  PT_CONTINUE:
375 	case  PT_KILL:
376 	case  PT_DETACH:
377 	case  PT_LWPINFO:
378 	case  PT_SYSCALL:
379 	case  PT_SYSCALLEMU:
380 	case  PT_DUMPCORE:
381 #ifdef PT_STEP
382 	case  PT_STEP:
383 #endif
384 	case  PT_SET_EVENT_MASK:
385 	case  PT_GET_EVENT_MASK:
386 	case  PT_GET_PROCESS_STATE:
387 		/*
388 		 * You can't do what you want to the process if:
389 		 *	(1) It's not being traced at all,
390 		 */
391 		if (!ISSET(t->p_slflag, PSL_TRACED)) {
392 			error = EPERM;
393 			break;
394 		}
395 
396 		/*
397 		 *	(2) it's being traced by procfs (which has
398 		 *	    different signal delivery semantics),
399 		 */
400 		if (ISSET(t->p_slflag, PSL_FSTRACE)) {
401 			uprintf("file system traced\n");
402 			error = EBUSY;
403 			break;
404 		}
405 
406 		/*
407 		 *	(3) it's not being traced by _you_, or
408 		 */
409 		if (t->p_pptr != p) {
410 			uprintf("parent %d != %d\n", t->p_pptr->p_pid,
411 			    p->p_pid);
412 			error = EBUSY;
413 			break;
414 		}
415 
416 		/*
417 		 *	(4) it's not currently stopped.
418 		 */
419 		if (t->p_stat != SSTOP || !t->p_waited /* XXXSMP */) {
420 			uprintf("stat %d flag %d\n", t->p_stat,
421 			    !t->p_waited);
422 			error = EBUSY;
423 			break;
424 		}
425 		break;
426 
427 	default:			/* It was not a legal request. */
428 		error = EINVAL;
429 		break;
430 	}
431 
432 	if (error == 0) {
433 		error = kauth_authorize_process(l->l_cred,
434 		    KAUTH_PROCESS_PTRACE, t, KAUTH_ARG(req),
435 		    NULL, NULL);
436 	}
437 	if (error == 0) {
438 		lt = lwp_find_first(t);
439 		if (lt == NULL)
440 			error = ESRCH;
441 	}
442 
443 	if (error != 0) {
444 		mutex_exit(proc_lock);
445 		mutex_exit(t->p_lock);
446 		rw_exit(&t->p_reflock);
447 		return error;
448 	}
449 
450 	/* Do single-step fixup if needed. */
451 	FIX_SSTEP(t);
452 	KASSERT(lt != NULL);
453 	lwp_addref(lt);
454 
455 	/*
456 	 * Which locks do we need held? XXX Ugly.
457 	 */
458 	switch (req) {
459 #ifdef PT_STEP
460 	case PT_STEP:
461 #endif
462 	case PT_CONTINUE:
463 	case PT_DETACH:
464 	case PT_KILL:
465 	case PT_SYSCALL:
466 	case PT_SYSCALLEMU:
467 	case PT_ATTACH:
468 	case PT_TRACE_ME:
469 		pheld = 1;
470 		break;
471 	default:
472 		mutex_exit(proc_lock);
473 		mutex_exit(t->p_lock);
474 		pheld = 0;
475 		break;
476 	}
477 
478 	/* Now do the operation. */
479 	write = 0;
480 	*retval = 0;
481 	tmp = 0;
482 	resume_all = 1;
483 
484 	switch (req) {
485 	case  PT_TRACE_ME:
486 		/* Just set the trace flag. */
487 		SET(t->p_slflag, PSL_TRACED);
488 		t->p_opptr = t->p_pptr;
489 		break;
490 
491 	case  PT_WRITE_I:		/* XXX no separate I and D spaces */
492 	case  PT_WRITE_D:
493 #if defined(__HAVE_RAS)
494 		/*
495 		 * Can't write to a RAS
496 		 */
497 		if (ras_lookup(t, SCARG(uap, addr)) != (void *)-1) {
498 			error = EACCES;
499 			break;
500 		}
501 #endif
502 		write = 1;
503 		tmp = SCARG(uap, data);
504 		/* FALLTHROUGH */
505 
506 	case  PT_READ_I:		/* XXX no separate I and D spaces */
507 	case  PT_READ_D:
508 		/* write = 0 done above. */
509 		iov.iov_base = (void *)&tmp;
510 		iov.iov_len = sizeof(tmp);
511 		uio.uio_iov = &iov;
512 		uio.uio_iovcnt = 1;
513 		uio.uio_offset = (off_t)(unsigned long)SCARG(uap, addr);
514 		uio.uio_resid = sizeof(tmp);
515 		uio.uio_rw = write ? UIO_WRITE : UIO_READ;
516 		UIO_SETUP_SYSSPACE(&uio);
517 
518 		error = process_domem(l, lt, &uio);
519 		if (!write)
520 			*retval = tmp;
521 		break;
522 
523 	case  PT_IO:
524 		error = copyin(SCARG(uap, addr), &piod, sizeof(piod));
525 		if (error)
526 			break;
527 		switch (piod.piod_op) {
528 		case PIOD_READ_D:
529 		case PIOD_READ_I:
530 			uio.uio_rw = UIO_READ;
531 			break;
532 		case PIOD_WRITE_D:
533 		case PIOD_WRITE_I:
534 			/*
535 			 * Can't write to a RAS
536 			 */
537 			if (ras_lookup(t, SCARG(uap, addr)) != (void *)-1) {
538 				return (EACCES);
539 			}
540 			uio.uio_rw = UIO_WRITE;
541 			break;
542 		default:
543 			error = EINVAL;
544 			break;
545 		}
546 		if (error)
547 			break;
548 		error = proc_vmspace_getref(l->l_proc, &vm);
549 		if (error)
550 			break;
551 		iov.iov_base = piod.piod_addr;
552 		iov.iov_len = piod.piod_len;
553 		uio.uio_iov = &iov;
554 		uio.uio_iovcnt = 1;
555 		uio.uio_offset = (off_t)(unsigned long)piod.piod_offs;
556 		uio.uio_resid = piod.piod_len;
557 		uio.uio_vmspace = vm;
558 
559 		error = process_domem(l, lt, &uio);
560 		piod.piod_len -= uio.uio_resid;
561 		(void) copyout(&piod, SCARG(uap, addr), sizeof(piod));
562 		uvmspace_free(vm);
563 		break;
564 
565 	case  PT_DUMPCORE:
566 		if ((path = SCARG(uap, addr)) != NULL) {
567 			char *dst;
568 			len = SCARG(uap, data);
569 
570 			if (len < 0 || len >= MAXPATHLEN) {
571 				error = EINVAL;
572 				break;
573 			}
574 			dst = kmem_alloc(len + 1, KM_SLEEP);
575 			if ((error = copyin(path, dst, len)) != 0) {
576 				kmem_free(dst, len + 1);
577 				break;
578 			}
579 			path = dst;
580 			path[len] = '\0';
581 		}
582 		error = (*coredump_vec)(lt, path);
583 		if (path)
584 			kmem_free(path, len + 1);
585 		break;
586 
587 #ifdef PT_STEP
588 	case  PT_STEP:
589 		/*
590 		 * From the 4.4BSD PRM:
591 		 * "Execution continues as in request PT_CONTINUE; however
592 		 * as soon as possible after execution of at least one
593 		 * instruction, execution stops again. [ ... ]"
594 		 */
595 #endif
596 	case  PT_CONTINUE:
597 	case  PT_SYSCALL:
598 	case  PT_DETACH:
599 		if (req == PT_SYSCALL) {
600 			if (!ISSET(t->p_slflag, PSL_SYSCALL)) {
601 				SET(t->p_slflag, PSL_SYSCALL);
602 #ifdef __HAVE_SYSCALL_INTERN
603 				(*t->p_emul->e_syscall_intern)(t);
604 #endif
605 			}
606 		} else {
607 			if (ISSET(t->p_slflag, PSL_SYSCALL)) {
608 				CLR(t->p_slflag, PSL_SYSCALL);
609 #ifdef __HAVE_SYSCALL_INTERN
610 				(*t->p_emul->e_syscall_intern)(t);
611 #endif
612 			}
613 		}
614 		t->p_trace_enabled = trace_is_enabled(t);
615 
616 		/*
617 		 * Pick up the LWPID, if supplied.  There are two cases:
618 		 * data < 0 : step or continue single thread, lwp = -data
619 		 * data > 0 in PT_STEP : step this thread, continue others
620 		 * For operations other than PT_STEP, data > 0 means
621 		 * data is the signo to deliver to the process.
622 		 */
623 		tmp = SCARG(uap, data);
624 		if (tmp >= 0) {
625 #ifdef PT_STEP
626 			if (req == PT_STEP)
627 				signo = 0;
628 			else
629 #endif
630 			{
631 				signo = tmp;
632 				tmp = 0;	/* don't search for LWP */
633 			}
634 		}
635 		else
636 			tmp = -tmp;
637 
638 		if (tmp > 0) {
639 			if (req == PT_DETACH) {
640 				error = EINVAL;
641 				break;
642 			}
643 			lwp_delref2 (lt);
644 			lt = lwp_find(t, tmp);
645 			if (lt == NULL) {
646 				error = ESRCH;
647 				break;
648 			}
649 			lwp_addref(lt);
650 			resume_all = 0;
651 			signo = 0;
652 		}
653 
654 		/*
655 		 * From the 4.4BSD PRM:
656 		 * "The data argument is taken as a signal number and the
657 		 * child's execution continues at location addr as if it
658 		 * incurred that signal.  Normally the signal number will
659 		 * be either 0 to indicate that the signal that caused the
660 		 * stop should be ignored, or that value fetched out of
661 		 * the process's image indicating which signal caused
662 		 * the stop.  If addr is (int *)1 then execution continues
663 		 * from where it stopped."
664 		 */
665 
666 		/* Check that the data is a valid signal number or zero. */
667 		if (signo < 0 || signo >= NSIG) {
668 			error = EINVAL;
669 			break;
670 		}
671 
672 		/* If the address parameter is not (int *)1, set the pc. */
673 		if ((int *)SCARG(uap, addr) != (int *)1) {
674 			error = process_set_pc(lt, SCARG(uap, addr));
675 			if (error != 0)
676 				break;
677 		}
678 #ifdef PT_STEP
679 		/*
680 		 * Arrange for a single-step, if that's requested and possible.
681 		 * More precisely, set the single step status as requested for
682 		 * the requested thread, and clear it for other threads.
683 		 */
684 		LIST_FOREACH(lt2, &t->p_lwps, l_sibling) {
685 			if (lt != lt2)
686 			{
687 				lwp_lock(lt2);
688 				process_sstep(lt2, 0);
689 				lwp_unlock(lt2);
690 			}
691 		}
692 		error = process_sstep(lt, req == PT_STEP);
693 		if (error)
694 			break;
695 #endif
696 		if (req == PT_DETACH) {
697 			CLR(t->p_slflag, PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL);
698 
699 			/* give process back to original parent or init */
700 			if (t->p_opptr != t->p_pptr) {
701 				struct proc *pp = t->p_opptr;
702 				proc_reparent(t, pp ? pp : initproc);
703 			}
704 
705 			/* not being traced any more */
706 			t->p_opptr = NULL;
707 		}
708 	sendsig:
709 		t->p_fpid = 0;
710 		/* Finally, deliver the requested signal (or none). */
711 		if (t->p_stat == SSTOP) {
712 			/*
713 			 * Unstop the process.  If it needs to take a
714 			 * signal, make all efforts to ensure that at
715 			 * an LWP runs to see it.
716 			 */
717 			t->p_xstat = signo;
718 			if (resume_all)
719 				proc_unstop(t);
720 			else
721 				lwp_unstop(lt);
722 		} else if (signo != 0) {
723 			KSI_INIT_EMPTY(&ksi);
724 			ksi.ksi_signo = signo;
725 			kpsignal2(t, &ksi);
726 		}
727 		break;
728 
729 	case  PT_SYSCALLEMU:
730 		if (!ISSET(t->p_slflag, PSL_SYSCALL) || t->p_stat != SSTOP) {
731 			error = EINVAL;
732 			break;
733 		}
734 		SET(t->p_slflag, PSL_SYSCALLEMU);
735 		break;
736 
737 	case  PT_KILL:
738 		/* just send the process a KILL signal. */
739 		signo = SIGKILL;
740 		goto sendsig;	/* in PT_CONTINUE, above. */
741 
742 	case  PT_ATTACH:
743 		/*
744 		 * Go ahead and set the trace flag.
745 		 * Save the old parent (it's reset in
746 		 *   _DETACH, and also in kern_exit.c:wait4()
747 		 * Reparent the process so that the tracing
748 		 *   proc gets to see all the action.
749 		 * Stop the target.
750 		 */
751 		t->p_opptr = t->p_pptr;
752 		if (t->p_pptr != p) {
753 			struct proc *parent = t->p_pptr;
754 
755 			if (parent->p_lock < t->p_lock) {
756 				if (!mutex_tryenter(parent->p_lock)) {
757 					mutex_exit(t->p_lock);
758 					mutex_enter(parent->p_lock);
759 				}
760 			} else if (parent->p_lock > t->p_lock) {
761 				mutex_enter(parent->p_lock);
762 			}
763 			parent->p_slflag |= PSL_CHTRACED;
764 			proc_reparent(t, p);
765 			if (parent->p_lock != t->p_lock)
766 				mutex_exit(parent->p_lock);
767 		}
768 		SET(t->p_slflag, PSL_TRACED);
769 		signo = SIGSTOP;
770 		goto sendsig;
771 
772 	case  PT_GET_EVENT_MASK:
773 		if (SCARG(uap, data) != sizeof(pe))
774 			return EINVAL;
775 		memset(&pe, 0, sizeof(pe));
776 		pe.pe_set_event = ISSET(t->p_slflag, PSL_TRACEFORK) ?
777 			PTRACE_FORK : 0;
778 		error = copyout(&pe, SCARG(uap, addr), sizeof(pe));
779 		break;
780 
781 	case  PT_SET_EVENT_MASK:
782 		if (SCARG(uap, data) != sizeof(pe))
783 			return EINVAL;
784 		if ((error = copyin(SCARG(uap, addr), &pe, sizeof(pe))) != 0)
785 			return error;
786 		if (pe.pe_set_event & PTRACE_FORK)
787 			SET(t->p_slflag, PSL_TRACEFORK);
788 		else
789 			CLR(t->p_slflag, PSL_TRACEFORK);
790 		break;
791 
792 	case  PT_GET_PROCESS_STATE:
793 		if (SCARG(uap, data) != sizeof(ps))
794 			return EINVAL;
795 		memset(&ps, 0, sizeof(ps));
796 		if (t->p_fpid) {
797 			ps.pe_report_event = PTRACE_FORK;
798 			ps.pe_other_pid = t->p_fpid;
799 		}
800 		error = copyout(&ps, SCARG(uap, addr), sizeof(ps));
801 		break;
802 
803 	case PT_LWPINFO:
804 		if (SCARG(uap, data) != sizeof(pl)) {
805 			error = EINVAL;
806 			break;
807 		}
808 		error = copyin(SCARG(uap, addr), &pl, sizeof(pl));
809 		if (error)
810 			break;
811 		tmp = pl.pl_lwpid;
812 		lwp_delref(lt);
813 		mutex_enter(t->p_lock);
814 		if (tmp == 0)
815 			lt = lwp_find_first(t);
816 		else {
817 			lt = lwp_find(t, tmp);
818 			if (lt == NULL) {
819 				mutex_exit(t->p_lock);
820 				error = ESRCH;
821 				break;
822 			}
823 			lt = LIST_NEXT(lt, l_sibling);
824 		}
825 		while (lt != NULL && !lwp_alive(lt))
826 			lt = LIST_NEXT(lt, l_sibling);
827 		pl.pl_lwpid = 0;
828 		pl.pl_event = 0;
829 		if (lt) {
830 			lwp_addref(lt);
831 			pl.pl_lwpid = lt->l_lid;
832 			if (lt->l_lid == t->p_sigctx.ps_lwp)
833 				pl.pl_event = PL_EVENT_SIGNAL;
834 		}
835 		mutex_exit(t->p_lock);
836 
837 		error = copyout(&pl, SCARG(uap, addr), sizeof(pl));
838 		break;
839 
840 #ifdef PT_SETREGS
841 	case  PT_SETREGS:
842 		write = 1;
843 #endif
844 #ifdef PT_GETREGS
845 	case  PT_GETREGS:
846 		/* write = 0 done above. */
847 #endif
848 #if defined(PT_SETREGS) || defined(PT_GETREGS)
849 		tmp = SCARG(uap, data);
850 		if (tmp != 0 && t->p_nlwps > 1) {
851 			lwp_delref(lt);
852 			mutex_enter(t->p_lock);
853 			lt = lwp_find(t, tmp);
854 			if (lt == NULL) {
855 				mutex_exit(t->p_lock);
856 				error = ESRCH;
857 				break;
858 			}
859 			lwp_addref(lt);
860 			mutex_exit(t->p_lock);
861 		}
862 		if (!process_validregs(lt))
863 			error = EINVAL;
864 		else {
865 			error = proc_vmspace_getref(l->l_proc, &vm);
866 			if (error)
867 				break;
868 			iov.iov_base = SCARG(uap, addr);
869 			iov.iov_len = sizeof(struct reg);
870 			uio.uio_iov = &iov;
871 			uio.uio_iovcnt = 1;
872 			uio.uio_offset = 0;
873 			uio.uio_resid = sizeof(struct reg);
874 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
875 			uio.uio_vmspace = vm;
876 
877 			error = process_doregs(l, lt, &uio);
878 			uvmspace_free(vm);
879 		}
880 		break;
881 #endif
882 
883 #ifdef PT_SETFPREGS
884 	case  PT_SETFPREGS:
885 		write = 1;
886 #endif
887 #ifdef PT_GETFPREGS
888 	case  PT_GETFPREGS:
889 		/* write = 0 done above. */
890 #endif
891 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
892 		tmp = SCARG(uap, data);
893 		if (tmp != 0 && t->p_nlwps > 1) {
894 			lwp_delref(lt);
895 			mutex_enter(t->p_lock);
896 			lt = lwp_find(t, tmp);
897 			if (lt == NULL) {
898 				mutex_exit(t->p_lock);
899 				error = ESRCH;
900 				break;
901 			}
902 			lwp_addref(lt);
903 			mutex_exit(t->p_lock);
904 		}
905 		if (!process_validfpregs(lt))
906 			error = EINVAL;
907 		else {
908 			error = proc_vmspace_getref(l->l_proc, &vm);
909 			if (error)
910 				break;
911 			iov.iov_base = SCARG(uap, addr);
912 			iov.iov_len = sizeof(struct fpreg);
913 			uio.uio_iov = &iov;
914 			uio.uio_iovcnt = 1;
915 			uio.uio_offset = 0;
916 			uio.uio_resid = sizeof(struct fpreg);
917 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
918 			uio.uio_vmspace = vm;
919 
920 			error = process_dofpregs(l, lt, &uio);
921 			uvmspace_free(vm);
922 		}
923 		break;
924 #endif
925 
926 #ifdef __HAVE_PTRACE_MACHDEP
927 	PTRACE_MACHDEP_REQUEST_CASES
928 		error = ptrace_machdep_dorequest(l, lt,
929 		    req, SCARG(uap, addr), SCARG(uap, data));
930 		break;
931 #endif
932 	}
933 
934 	if (pheld) {
935 		mutex_exit(t->p_lock);
936 		mutex_exit(proc_lock);
937 	}
938 	if (lt != NULL)
939 		lwp_delref(lt);
940 	rw_exit(&t->p_reflock);
941 
942 	return error;
943 }
944 
945 int
946 process_doregs(struct lwp *curl /*tracer*/,
947     struct lwp *l /*traced*/,
948     struct uio *uio)
949 {
950 #if defined(PT_GETREGS) || defined(PT_SETREGS)
951 	int error;
952 	struct reg r;
953 	char *kv;
954 	int kl;
955 
956 	if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r))
957 		return EINVAL;
958 
959 	kl = sizeof(r);
960 	kv = (char *)&r;
961 
962 	kv += uio->uio_offset;
963 	kl -= uio->uio_offset;
964 	if ((size_t)kl > uio->uio_resid)
965 		kl = uio->uio_resid;
966 
967 	error = process_read_regs(l, &r);
968 	if (error == 0)
969 		error = uiomove(kv, kl, uio);
970 	if (error == 0 && uio->uio_rw == UIO_WRITE) {
971 		if (l->l_stat != LSSTOP)
972 			error = EBUSY;
973 		else
974 			error = process_write_regs(l, &r);
975 	}
976 
977 	uio->uio_offset = 0;
978 	return (error);
979 #else
980 	return (EINVAL);
981 #endif
982 }
983 
984 int
985 process_validregs(struct lwp *l)
986 {
987 
988 #if defined(PT_SETREGS) || defined(PT_GETREGS)
989 	return ((l->l_flag & LW_SYSTEM) == 0);
990 #else
991 	return (0);
992 #endif
993 }
994 
995 int
996 process_dofpregs(struct lwp *curl /*tracer*/,
997     struct lwp *l /*traced*/,
998     struct uio *uio)
999 {
1000 #if defined(PT_GETFPREGS) || defined(PT_SETFPREGS)
1001 	int error;
1002 	struct fpreg r;
1003 	char *kv;
1004 	size_t kl;
1005 
1006 	if (uio->uio_offset < 0 || uio->uio_offset > (off_t)sizeof(r))
1007 		return EINVAL;
1008 
1009 	kl = sizeof(r);
1010 	kv = (char *)&r;
1011 
1012 	kv += uio->uio_offset;
1013 	kl -= uio->uio_offset;
1014 	if ((size_t)kl > uio->uio_resid)
1015 		kl = uio->uio_resid;
1016 
1017 	error = process_read_fpregs(l, &r, &kl);
1018 	if (error == 0)
1019 		error = uiomove(kv, kl, uio);
1020 	if (error == 0 && uio->uio_rw == UIO_WRITE) {
1021 		if (l->l_stat != LSSTOP)
1022 			error = EBUSY;
1023 		else
1024 			error = process_write_fpregs(l, &r, kl);
1025 	}
1026 	uio->uio_offset = 0;
1027 	return (error);
1028 #else
1029 	return (EINVAL);
1030 #endif
1031 }
1032 
1033 int
1034 process_validfpregs(struct lwp *l)
1035 {
1036 
1037 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
1038 	return ((l->l_flag & LW_SYSTEM) == 0);
1039 #else
1040 	return (0);
1041 #endif
1042 }
1043 #endif /* PTRACE */
1044 
1045 #if defined(KTRACE) || defined(PTRACE)
1046 int
1047 process_domem(struct lwp *curl /*tracer*/,
1048     struct lwp *l /*traced*/,
1049     struct uio *uio)
1050 {
1051 	struct proc *p = l->l_proc;	/* traced */
1052 	struct vmspace *vm;
1053 	int error;
1054 
1055 	size_t len;
1056 #ifdef PMAP_NEED_PROCWR
1057 	vaddr_t	addr;
1058 #endif
1059 
1060 	error = 0;
1061 	len = uio->uio_resid;
1062 
1063 	if (len == 0)
1064 		return (0);
1065 
1066 #ifdef PMAP_NEED_PROCWR
1067 	addr = uio->uio_offset;
1068 #endif
1069 
1070 	vm = p->p_vmspace;
1071 
1072 	mutex_enter(&vm->vm_map.misc_lock);
1073 	if ((l->l_flag & LW_WEXIT) || vm->vm_refcnt < 1)
1074 		error = EFAULT;
1075 	if (error == 0)
1076 		p->p_vmspace->vm_refcnt++;  /* XXX */
1077 	mutex_exit(&vm->vm_map.misc_lock);
1078 	if (error != 0)
1079 		return (error);
1080 	error = uvm_io(&vm->vm_map, uio);
1081 	uvmspace_free(vm);
1082 
1083 #ifdef PMAP_NEED_PROCWR
1084 	if (error == 0 && uio->uio_rw == UIO_WRITE)
1085 		pmap_procwr(p, addr, len);
1086 #endif
1087 	return (error);
1088 }
1089 #endif /* KTRACE || PTRACE */
1090 
1091 #if defined(KTRACE) || defined(PTRACE)
1092 void
1093 process_stoptrace(void)
1094 {
1095 	struct lwp *l = curlwp;
1096 	struct proc *p = l->l_proc, *pp;
1097 
1098 	mutex_enter(proc_lock);
1099 	mutex_enter(p->p_lock);
1100 	pp = p->p_pptr;
1101 	if (pp->p_pid == 1) {
1102 		CLR(p->p_slflag, PSL_SYSCALL);	/* XXXSMP */
1103 		mutex_exit(p->p_lock);
1104 		mutex_exit(proc_lock);
1105 		return;
1106 	}
1107 
1108 	p->p_xstat = SIGTRAP;
1109 	proc_stop(p, 1, SIGSTOP);
1110 	mutex_exit(proc_lock);
1111 
1112 	if (sigispending(l, 0)) {
1113 		lwp_lock(l);
1114 		l->l_flag |= LW_PENDSIG;
1115 		lwp_unlock(l);
1116 	}
1117 	mutex_exit(p->p_lock);
1118 }
1119 #endif	/* KTRACE || PTRACE */
1120