xref: /dragonfly/sys/kern/sys_process.c (revision 650094e1) 
1 /*
2  * Copyright (c) 1994, Sean Eric Fagan
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  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by Sean Eric Fagan.
16  * 4. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  * $FreeBSD: src/sys/kern/sys_process.c,v 1.51.2.6 2003/01/08 03:06:45 kan Exp $
32  * $DragonFly: src/sys/kern/sys_process.c,v 1.30 2007/02/19 01:14:23 corecode Exp $
33  */
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/sysproto.h>
38 #include <sys/proc.h>
39 #include <sys/priv.h>
40 #include <sys/vnode.h>
41 #include <sys/ptrace.h>
42 #include <sys/reg.h>
43 #include <sys/lock.h>
44 
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47 #include <vm/vm_map.h>
48 #include <vm/vm_page.h>
49 
50 #include <sys/user.h>
51 #include <vfs/procfs/procfs.h>
52 
53 #include <sys/thread2.h>
54 #include <sys/spinlock2.h>
55 
56 /* use the equivalent procfs code */
57 #if 0
58 static int
59 pread (struct proc *procp, unsigned int addr, unsigned int *retval) {
60 	int		rv;
61 	vm_map_t	map, tmap;
62 	vm_object_t	object;
63 	vm_offset_t	kva = 0;
64 	int		page_offset;	/* offset into page */
65 	vm_offset_t	pageno;		/* page number */
66 	vm_map_entry_t	out_entry;
67 	vm_prot_t	out_prot;
68 	boolean_t	wired;
69 	vm_pindex_t	pindex;
70 
71 	/* Map page into kernel space */
72 
73 	map = &procp->p_vmspace->vm_map;
74 
75 	page_offset = addr - trunc_page(addr);
76 	pageno = trunc_page(addr);
77 
78 	tmap = map;
79 	rv = vm_map_lookup(&tmap, pageno, VM_PROT_READ, &out_entry,
80 			   &object, &pindex, &out_prot, &wired);
81 
82 	if (rv != KERN_SUCCESS)
83 		return EINVAL;
84 
85 	vm_map_lookup_done (tmap, out_entry, 0);
86 
87 	/* Find space in kernel_map for the page we're interested in */
88 	rv = vm_map_find (&kernel_map, object, IDX_TO_OFF(pindex),
89 			  &kva,
90 			  PAGE_SIZE, PAGE_SIZE,
91 			  0, VM_MAPTYPE_NORMAL,
92 			  VM_PROT_ALL, VM_PROT_ALL,
93 			  0);
94 
95 	if (!rv) {
96 		vm_object_reference XXX (object);
97 
98 		rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0);
99 		if (!rv) {
100 			*retval = 0;
101 			bcopy ((caddr_t)kva + page_offset,
102 			       retval, sizeof *retval);
103 		}
104 		vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE);
105 	}
106 
107 	return rv;
108 }
109 
110 static int
111 pwrite (struct proc *procp, unsigned int addr, unsigned int datum) {
112 	int		rv;
113 	vm_map_t	map, tmap;
114 	vm_object_t	object;
115 	vm_offset_t	kva = 0;
116 	int		page_offset;	/* offset into page */
117 	vm_offset_t	pageno;		/* page number */
118 	vm_map_entry_t	out_entry;
119 	vm_prot_t	out_prot;
120 	boolean_t	wired;
121 	vm_pindex_t	pindex;
122 	boolean_t	fix_prot = 0;
123 
124 	/* Map page into kernel space */
125 
126 	map = &procp->p_vmspace->vm_map;
127 
128 	page_offset = addr - trunc_page(addr);
129 	pageno = trunc_page(addr);
130 
131 	/*
132 	 * Check the permissions for the area we're interested in.
133 	 */
134 
135 	if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE,
136 				     VM_PROT_WRITE, FALSE) == FALSE) {
137 		/*
138 		 * If the page was not writable, we make it so.
139 		 * XXX It is possible a page may *not* be read/executable,
140 		 * if a process changes that!
141 		 */
142 		fix_prot = 1;
143 		/* The page isn't writable, so let's try making it so... */
144 		if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE,
145 			VM_PROT_ALL, 0)) != KERN_SUCCESS)
146 		  return EFAULT;	/* I guess... */
147 	}
148 
149 	/*
150 	 * Now we need to get the page.  out_entry, out_prot, wired, and
151 	 * single_use aren't used.  One would think the vm code would be
152 	 * a *bit* nicer...  We use tmap because vm_map_lookup() can
153 	 * change the map argument.
154 	 */
155 
156 	tmap = map;
157 	rv = vm_map_lookup(&tmap, pageno, VM_PROT_WRITE, &out_entry,
158 			   &object, &pindex, &out_prot, &wired);
159 	if (rv != KERN_SUCCESS)
160 		return EINVAL;
161 
162 	/*
163 	 * Okay, we've got the page.  Let's release tmap.
164 	 */
165 	vm_map_lookup_done (tmap, out_entry, 0);
166 
167 	/*
168 	 * Fault the page in...
169 	 */
170 	rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE);
171 	if (rv != KERN_SUCCESS)
172 		return EFAULT;
173 
174 	/* Find space in kernel_map for the page we're interested in */
175 	rv = vm_map_find (&kernel_map, object, IDX_TO_OFF(pindex),
176 			  &kva,
177 			  PAGE_SIZE, PAGE_SIZE,
178 			  0, VM_MAPTYPE_NORMAL,
179 			  VM_PROT_ALL, VM_PROT_ALL,
180 			  0);
181 	if (!rv) {
182 		vm_object_reference XXX (object);
183 
184 		rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0);
185 		if (!rv) {
186 		  bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum);
187 		}
188 		vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE);
189 	}
190 
191 	if (fix_prot)
192 		vm_map_protect (map, pageno, pageno + PAGE_SIZE,
193 			VM_PROT_READ|VM_PROT_EXECUTE, 0);
194 	return rv;
195 }
196 #endif
197 
198 /*
199  * Process debugging system call.
200  *
201  * MPALMOSTSAFE
202  */
203 int
204 sys_ptrace(struct ptrace_args *uap)
205 {
206 	struct proc *p = curproc;
207 
208 	/*
209 	 * XXX this obfuscation is to reduce stack usage, but the register
210 	 * structs may be too large to put on the stack anyway.
211 	 */
212 	union {
213 		struct ptrace_io_desc piod;
214 		struct dbreg dbreg;
215 		struct fpreg fpreg;
216 		struct reg reg;
217 	} r;
218 	void *addr;
219 	int error = 0;
220 
221 	addr = &r;
222 	switch (uap->req) {
223 	case PT_GETREGS:
224 	case PT_GETFPREGS:
225 #ifdef PT_GETDBREGS
226 	case PT_GETDBREGS:
227 #endif
228 		break;
229 	case PT_SETREGS:
230 		error = copyin(uap->addr, &r.reg, sizeof r.reg);
231 		break;
232 	case PT_SETFPREGS:
233 		error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg);
234 		break;
235 #ifdef PT_SETDBREGS
236 	case PT_SETDBREGS:
237 		error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg);
238 		break;
239 #endif
240 	case PT_IO:
241 		error = copyin(uap->addr, &r.piod, sizeof r.piod);
242 		break;
243 	default:
244 		addr = uap->addr;
245 	}
246 	if (error)
247 		return (error);
248 
249 	error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data,
250 			&uap->sysmsg_result);
251 	if (error)
252 		return (error);
253 
254 	switch (uap->req) {
255 	case PT_IO:
256 		(void)copyout(&r.piod, uap->addr, sizeof r.piod);
257 		break;
258 	case PT_GETREGS:
259 		error = copyout(&r.reg, uap->addr, sizeof r.reg);
260 		break;
261 	case PT_GETFPREGS:
262 		error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg);
263 		break;
264 #ifdef PT_GETDBREGS
265 	case PT_GETDBREGS:
266 		error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg);
267 		break;
268 #endif
269 	}
270 
271 	return (error);
272 }
273 
274 int
275 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr,
276 	    int data, int *res)
277 {
278 	struct proc *p, *pp;
279 	struct lwp *lp;
280 	struct iovec iov;
281 	struct uio uio;
282 	struct ptrace_io_desc *piod;
283 	int error = 0;
284 	int write, tmp;
285 	int t;
286 
287 	lwkt_gettoken(&proc_token);
288 
289 	write = 0;
290 	if (req == PT_TRACE_ME) {
291 		p = curp;
292 		PHOLD(p);
293 	} else {
294 		if ((p = pfind(pid)) == NULL) {
295 			lwkt_reltoken(&proc_token);
296 			return ESRCH;
297 		}
298 	}
299 	if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
300 		PRELE(p);
301 		lwkt_reltoken(&proc_token);
302 		return (ESRCH);
303 	}
304 
305 	lwkt_gettoken(&p->p_token);
306 	/* Can't trace a process that's currently exec'ing. */
307 	if ((p->p_flags & P_INEXEC) != 0) {
308 		lwkt_reltoken(&p->p_token);
309 		PRELE(p);
310 		lwkt_reltoken(&proc_token);
311 		return EAGAIN;
312 	}
313 
314 	/*
315 	 * Permissions check
316 	 */
317 	switch (req) {
318 	case PT_TRACE_ME:
319 		/* Always legal. */
320 		break;
321 
322 	case PT_ATTACH:
323 		/* Self */
324 		if (p->p_pid == curp->p_pid) {
325 			lwkt_reltoken(&p->p_token);
326 			PRELE(p);
327 			lwkt_reltoken(&proc_token);
328 			return EINVAL;
329 		}
330 
331 		/* Already traced */
332 		if (p->p_flags & P_TRACED) {
333 			lwkt_reltoken(&p->p_token);
334 			PRELE(p);
335 			lwkt_reltoken(&proc_token);
336 			return EBUSY;
337 		}
338 
339 		if (curp->p_flags & P_TRACED)
340 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr)
341 				if (pp == p) {
342 					lwkt_reltoken(&p->p_token);
343 					PRELE(p);
344 					lwkt_reltoken(&proc_token);
345 					return (EINVAL);
346 				}
347 
348 		/* not owned by you, has done setuid (unless you're root) */
349 		if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) ||
350 		     (p->p_flags & P_SUGID)) {
351 			if ((error = priv_check_cred(curp->p_ucred, PRIV_ROOT, 0)) != 0) {
352 				lwkt_reltoken(&p->p_token);
353 				PRELE(p);
354 				lwkt_reltoken(&proc_token);
355 				return error;
356 			}
357 		}
358 
359 		/* can't trace init when securelevel > 0 */
360 		if (securelevel > 0 && p->p_pid == 1) {
361 			lwkt_reltoken(&p->p_token);
362 			PRELE(p);
363 			lwkt_reltoken(&proc_token);
364 			return EPERM;
365 		}
366 
367 		/* OK */
368 		break;
369 
370 	case PT_READ_I:
371 	case PT_READ_D:
372 	case PT_WRITE_I:
373 	case PT_WRITE_D:
374 	case PT_IO:
375 	case PT_CONTINUE:
376 	case PT_KILL:
377 	case PT_STEP:
378 	case PT_DETACH:
379 #ifdef PT_GETREGS
380 	case PT_GETREGS:
381 #endif
382 #ifdef PT_SETREGS
383 	case PT_SETREGS:
384 #endif
385 #ifdef PT_GETFPREGS
386 	case PT_GETFPREGS:
387 #endif
388 #ifdef PT_SETFPREGS
389 	case PT_SETFPREGS:
390 #endif
391 #ifdef PT_GETDBREGS
392 	case PT_GETDBREGS:
393 #endif
394 #ifdef PT_SETDBREGS
395 	case PT_SETDBREGS:
396 #endif
397 		/* not being traced... */
398 		if ((p->p_flags & P_TRACED) == 0) {
399 			lwkt_reltoken(&p->p_token);
400 			PRELE(p);
401 			lwkt_reltoken(&proc_token);
402 			return EPERM;
403 		}
404 
405 		/* not being traced by YOU */
406 		if (p->p_pptr != curp) {
407 			lwkt_reltoken(&p->p_token);
408 			PRELE(p);
409 			lwkt_reltoken(&proc_token);
410 			return EBUSY;
411 		}
412 
413 		/* not currently stopped */
414 		if (p->p_stat != SSTOP ||
415 		    (p->p_flags & P_WAITED) == 0) {
416 			lwkt_reltoken(&p->p_token);
417 			PRELE(p);
418 			lwkt_reltoken(&proc_token);
419 			return EBUSY;
420 		}
421 
422 		/* OK */
423 		break;
424 
425 	default:
426 		lwkt_reltoken(&p->p_token);
427 		PRELE(p);
428 		lwkt_reltoken(&proc_token);
429 		return EINVAL;
430 	}
431 
432 	/* XXX lwp */
433 	lp = FIRST_LWP_IN_PROC(p);
434 #ifdef FIX_SSTEP
435 	/*
436 	 * Single step fixup ala procfs
437 	 */
438 	FIX_SSTEP(lp);
439 #endif
440 
441 	/*
442 	 * Actually do the requests
443 	 */
444 
445 	*res = 0;
446 
447 	switch (req) {
448 	case PT_TRACE_ME:
449 		/* set my trace flag and "owner" so it can read/write me */
450 		p->p_flags |= P_TRACED;
451 		p->p_oppid = p->p_pptr->p_pid;
452 		lwkt_reltoken(&p->p_token);
453 		PRELE(p);
454 		lwkt_reltoken(&proc_token);
455 		return 0;
456 
457 	case PT_ATTACH:
458 		/* security check done above */
459 		p->p_flags |= P_TRACED;
460 		p->p_oppid = p->p_pptr->p_pid;
461 		if (p->p_pptr != curp)
462 			proc_reparent(p, curp);
463 		data = SIGSTOP;
464 		goto sendsig;	/* in PT_CONTINUE below */
465 
466 	case PT_STEP:
467 	case PT_CONTINUE:
468 	case PT_DETACH:
469 		/* Zero means do not send any signal */
470 		if (data < 0 || data > _SIG_MAXSIG) {
471 			lwkt_reltoken(&p->p_token);
472 			PRELE(p);
473 			lwkt_reltoken(&proc_token);
474 			return EINVAL;
475 		}
476 
477 		LWPHOLD(lp);
478 
479 		if (req == PT_STEP) {
480 			if ((error = ptrace_single_step (lp))) {
481 				LWPRELE(lp);
482 				lwkt_reltoken(&p->p_token);
483 				PRELE(p);
484 				lwkt_reltoken(&proc_token);
485 				return error;
486 			}
487 		}
488 
489 		if (addr != (void *)1) {
490 			if ((error = ptrace_set_pc (lp,
491 			    (u_long)(uintfptr_t)addr))) {
492 				LWPRELE(lp);
493 				lwkt_reltoken(&p->p_token);
494 				PRELE(p);
495 				lwkt_reltoken(&proc_token);
496 				return error;
497 			}
498 		}
499 		LWPRELE(lp);
500 
501 		if (req == PT_DETACH) {
502 			/* reset process parent */
503 			if (p->p_oppid != p->p_pptr->p_pid) {
504 				struct proc *pp;
505 
506 				pp = pfind(p->p_oppid);
507 				proc_reparent(p, pp ? pp : initproc);
508 				if (pp != NULL)
509 					PRELE(pp);
510 			}
511 
512 			p->p_flags &= ~(P_TRACED | P_WAITED);
513 			p->p_oppid = 0;
514 
515 			/* should we send SIGCHLD? */
516 		}
517 
518 	sendsig:
519 		/*
520 		 * Deliver or queue signal.  If the process is stopped
521 		 * force it to be SACTIVE again.
522 		 */
523 		crit_enter();
524 		if (p->p_stat == SSTOP) {
525 			p->p_xstat = data;
526 			proc_unstop(p);
527 		} else if (data) {
528 			ksignal(p, data);
529 		}
530 		crit_exit();
531 		lwkt_reltoken(&p->p_token);
532 		PRELE(p);
533 		lwkt_reltoken(&proc_token);
534 		return 0;
535 
536 	case PT_WRITE_I:
537 	case PT_WRITE_D:
538 		write = 1;
539 		/* fallthrough */
540 	case PT_READ_I:
541 	case PT_READ_D:
542 		/*
543 		 * NOTE! uio_offset represents the offset in the target
544 		 * process.  The iov is in the current process (the guy
545 		 * making the ptrace call) so uio_td must be the current
546 		 * process (though for a SYSSPACE transfer it doesn't
547 		 * really matter).
548 		 */
549 		tmp = 0;
550 		/* write = 0 set above */
551 		iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
552 		iov.iov_len = sizeof(int);
553 		uio.uio_iov = &iov;
554 		uio.uio_iovcnt = 1;
555 		uio.uio_offset = (off_t)(uintptr_t)addr;
556 		uio.uio_resid = sizeof(int);
557 		uio.uio_segflg = UIO_SYSSPACE;
558 		uio.uio_rw = write ? UIO_WRITE : UIO_READ;
559 		uio.uio_td = curthread;
560 		error = procfs_domem(curp, lp, NULL, &uio);
561 		if (uio.uio_resid != 0) {
562 			/*
563 			 * XXX procfs_domem() doesn't currently return ENOSPC,
564 			 * so I think write() can bogusly return 0.
565 			 * XXX what happens for short writes?  We don't want
566 			 * to write partial data.
567 			 * XXX procfs_domem() returns EPERM for other invalid
568 			 * addresses.  Convert this to EINVAL.  Does this
569 			 * clobber returns of EPERM for other reasons?
570 			 */
571 			if (error == 0 || error == ENOSPC || error == EPERM)
572 				error = EINVAL;	/* EOF */
573 		}
574 		if (!write)
575 			*res = tmp;
576 		lwkt_reltoken(&p->p_token);
577 		PRELE(p);
578 		lwkt_reltoken(&proc_token);
579 		return (error);
580 
581 	case PT_IO:
582 		/*
583 		 * NOTE! uio_offset represents the offset in the target
584 		 * process.  The iov is in the current process (the guy
585 		 * making the ptrace call) so uio_td must be the current
586 		 * process.
587 		 */
588 		piod = addr;
589 		iov.iov_base = piod->piod_addr;
590 		iov.iov_len = piod->piod_len;
591 		uio.uio_iov = &iov;
592 		uio.uio_iovcnt = 1;
593 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
594 		uio.uio_resid = piod->piod_len;
595 		uio.uio_segflg = UIO_USERSPACE;
596 		uio.uio_td = curthread;
597 		switch (piod->piod_op) {
598 		case PIOD_READ_D:
599 		case PIOD_READ_I:
600 			uio.uio_rw = UIO_READ;
601 			break;
602 		case PIOD_WRITE_D:
603 		case PIOD_WRITE_I:
604 			uio.uio_rw = UIO_WRITE;
605 			break;
606 		default:
607 			lwkt_reltoken(&p->p_token);
608 			PRELE(p);
609 			lwkt_reltoken(&proc_token);
610 			return (EINVAL);
611 		}
612 		error = procfs_domem(curp, lp, NULL, &uio);
613 		piod->piod_len -= uio.uio_resid;
614 		lwkt_reltoken(&p->p_token);
615 		PRELE(p);
616 		lwkt_reltoken(&proc_token);
617 		return (error);
618 
619 	case PT_KILL:
620 		data = SIGKILL;
621 		goto sendsig;	/* in PT_CONTINUE above */
622 
623 #ifdef PT_SETREGS
624 	case PT_SETREGS:
625 		write = 1;
626 		/* fallthrough */
627 #endif /* PT_SETREGS */
628 #ifdef PT_GETREGS
629 	case PT_GETREGS:
630 		/* write = 0 above */
631 #endif /* PT_SETREGS */
632 #if defined(PT_SETREGS) || defined(PT_GETREGS)
633 		if (!procfs_validregs(lp)) {	/* no P_SYSTEM procs please */
634 			lwkt_reltoken(&p->p_token);
635 			PRELE(p);
636 			lwkt_reltoken(&proc_token);
637 			return EINVAL;
638 		} else {
639 			iov.iov_base = addr;
640 			iov.iov_len = sizeof(struct reg);
641 			uio.uio_iov = &iov;
642 			uio.uio_iovcnt = 1;
643 			uio.uio_offset = 0;
644 			uio.uio_resid = sizeof(struct reg);
645 			uio.uio_segflg = UIO_SYSSPACE;
646 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
647 			uio.uio_td = curthread;
648 			t = procfs_doregs(curp, lp, NULL, &uio);
649 			lwkt_reltoken(&p->p_token);
650 			PRELE(p);
651 			lwkt_reltoken(&proc_token);
652 			return t;
653 		}
654 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */
655 
656 #ifdef PT_SETFPREGS
657 	case PT_SETFPREGS:
658 		write = 1;
659 		/* fallthrough */
660 #endif /* PT_SETFPREGS */
661 #ifdef PT_GETFPREGS
662 	case PT_GETFPREGS:
663 		/* write = 0 above */
664 #endif /* PT_SETFPREGS */
665 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
666 		if (!procfs_validfpregs(lp)) {	/* no P_SYSTEM procs please */
667 			lwkt_reltoken(&p->p_token);
668 			PRELE(p);
669 			lwkt_reltoken(&proc_token);
670 			return EINVAL;
671 		} else {
672 			iov.iov_base = addr;
673 			iov.iov_len = sizeof(struct fpreg);
674 			uio.uio_iov = &iov;
675 			uio.uio_iovcnt = 1;
676 			uio.uio_offset = 0;
677 			uio.uio_resid = sizeof(struct fpreg);
678 			uio.uio_segflg = UIO_SYSSPACE;
679 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
680 			uio.uio_td = curthread;
681 			t = procfs_dofpregs(curp, lp, NULL, &uio);
682 			lwkt_reltoken(&p->p_token);
683 			PRELE(p);
684 			lwkt_reltoken(&proc_token);
685 			return t;
686 		}
687 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */
688 
689 #ifdef PT_SETDBREGS
690 	case PT_SETDBREGS:
691 		write = 1;
692 		/* fallthrough */
693 #endif /* PT_SETDBREGS */
694 #ifdef PT_GETDBREGS
695 	case PT_GETDBREGS:
696 		/* write = 0 above */
697 #endif /* PT_SETDBREGS */
698 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS)
699 		if (!procfs_validdbregs(lp)) {	/* no P_SYSTEM procs please */
700 			lwkt_reltoken(&p->p_token);
701 			PRELE(p);
702 			lwkt_reltoken(&proc_token);
703 			return EINVAL;
704 		} else {
705 			iov.iov_base = addr;
706 			iov.iov_len = sizeof(struct dbreg);
707 			uio.uio_iov = &iov;
708 			uio.uio_iovcnt = 1;
709 			uio.uio_offset = 0;
710 			uio.uio_resid = sizeof(struct dbreg);
711 			uio.uio_segflg = UIO_SYSSPACE;
712 			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
713 			uio.uio_td = curthread;
714 			t = procfs_dodbregs(curp, lp, NULL, &uio);
715 			lwkt_reltoken(&p->p_token);
716 			PRELE(p);
717 			lwkt_reltoken(&proc_token);
718 			return t;
719 		}
720 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */
721 
722 	default:
723 		break;
724 	}
725 
726 	lwkt_reltoken(&p->p_token);
727 	PRELE(p);
728 	lwkt_reltoken(&proc_token);
729 
730 	return 0;
731 }
732 
733 int
734 trace_req(struct proc *p)
735 {
736 	return 1;
737 }
738 
739 /*
740  * stopevent()
741  *
742  * Stop a process because of a procfs event.  Stay stopped until p->p_step
743  * is cleared (cleared by PIOCCONT in procfs).
744  *
745  * MPSAFE
746  */
747 void
748 stopevent(struct proc *p, unsigned int event, unsigned int val)
749 {
750 	/*
751 	 * Set event info.  Recheck p_stops in case we are
752 	 * racing a close() on procfs.
753 	 */
754 	spin_lock(&p->p_spin);
755 	if ((p->p_stops & event) == 0) {
756 		spin_unlock(&p->p_spin);
757 		return;
758 	}
759 	p->p_xstat = val;
760 	p->p_stype = event;
761 	p->p_step = 1;
762 	tsleep_interlock(&p->p_step, 0);
763 	spin_unlock(&p->p_spin);
764 
765 	/*
766 	 * Wakeup any PIOCWAITing procs and wait for p_step to
767 	 * be cleared.
768 	 */
769 	for (;;) {
770 		wakeup(&p->p_stype);
771 		tsleep(&p->p_step, PINTERLOCKED, "stopevent", 0);
772 		spin_lock(&p->p_spin);
773 		if (p->p_step == 0) {
774 			spin_unlock(&p->p_spin);
775 			break;
776 		}
777 		tsleep_interlock(&p->p_step, 0);
778 		spin_unlock(&p->p_spin);
779 	}
780 }
781 
782