xref: /freebsd/sys/kern/sys_process.c (revision 7ef62cebc2f965b0f640263e179276928885e33d)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1994, Sean Eric Fagan
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  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by Sean Eric Fagan.
18  * 4. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/ktr.h>
40 #include <sys/limits.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/reg.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/sysent.h>
46 #include <sys/sysproto.h>
47 #include <sys/priv.h>
48 #include <sys/proc.h>
49 #include <sys/vnode.h>
50 #include <sys/ptrace.h>
51 #include <sys/rwlock.h>
52 #include <sys/sx.h>
53 #include <sys/malloc.h>
54 #include <sys/signalvar.h>
55 #include <sys/caprights.h>
56 #include <sys/filedesc.h>
57 
58 #include <security/audit/audit.h>
59 
60 #include <vm/vm.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_extern.h>
63 #include <vm/vm_map.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_param.h>
68 
69 #ifdef COMPAT_FREEBSD32
70 #include <sys/procfs.h>
71 #endif
72 
73 /* Assert it's safe to unlock a process, e.g. to allocate working memory */
74 #define	PROC_ASSERT_TRACEREQ(p)	MPASS(((p)->p_flag2 & P2_PTRACEREQ) != 0)
75 
76 /*
77  * Functions implemented using PROC_ACTION():
78  *
79  * proc_read_regs(proc, regs)
80  *	Get the current user-visible register set from the process
81  *	and copy it into the regs structure (<machine/reg.h>).
82  *	The process is stopped at the time read_regs is called.
83  *
84  * proc_write_regs(proc, regs)
85  *	Update the current register set from the passed in regs
86  *	structure.  Take care to avoid clobbering special CPU
87  *	registers or privileged bits in the PSL.
88  *	Depending on the architecture this may have fix-up work to do,
89  *	especially if the IAR or PCW are modified.
90  *	The process is stopped at the time write_regs is called.
91  *
92  * proc_read_fpregs, proc_write_fpregs
93  *	deal with the floating point register set, otherwise as above.
94  *
95  * proc_read_dbregs, proc_write_dbregs
96  *	deal with the processor debug register set, otherwise as above.
97  *
98  * proc_sstep(proc)
99  *	Arrange for the process to trap after executing a single instruction.
100  */
101 
102 #define	PROC_ACTION(action) do {					\
103 	int error;							\
104 									\
105 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
106 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
107 		error = EIO;						\
108 	else								\
109 		error = (action);					\
110 	return (error);							\
111 } while (0)
112 
113 int
114 proc_read_regs(struct thread *td, struct reg *regs)
115 {
116 
117 	PROC_ACTION(fill_regs(td, regs));
118 }
119 
120 int
121 proc_write_regs(struct thread *td, struct reg *regs)
122 {
123 
124 	PROC_ACTION(set_regs(td, regs));
125 }
126 
127 int
128 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
129 {
130 
131 	PROC_ACTION(fill_dbregs(td, dbregs));
132 }
133 
134 int
135 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
136 {
137 
138 	PROC_ACTION(set_dbregs(td, dbregs));
139 }
140 
141 /*
142  * Ptrace doesn't support fpregs at all, and there are no security holes
143  * or translations for fpregs, so we can just copy them.
144  */
145 int
146 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
147 {
148 
149 	PROC_ACTION(fill_fpregs(td, fpregs));
150 }
151 
152 int
153 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
154 {
155 
156 	PROC_ACTION(set_fpregs(td, fpregs));
157 }
158 
159 static struct regset *
160 proc_find_regset(struct thread *td, int note)
161 {
162 	struct regset **regsetp, **regset_end, *regset;
163 	struct sysentvec *sv;
164 
165 	sv = td->td_proc->p_sysent;
166 	regsetp = sv->sv_regset_begin;
167 	if (regsetp == NULL)
168 		return (NULL);
169 	regset_end = sv->sv_regset_end;
170 	MPASS(regset_end != NULL);
171 	for (; regsetp < regset_end; regsetp++) {
172 		regset = *regsetp;
173 		if (regset->note != note)
174 			continue;
175 
176 		return (regset);
177 	}
178 
179 	return (NULL);
180 }
181 
182 static int
183 proc_read_regset(struct thread *td, int note, struct iovec *iov)
184 {
185 	struct regset *regset;
186 	struct proc *p;
187 	void *buf;
188 	size_t size;
189 	int error;
190 
191 	regset = proc_find_regset(td, note);
192 	if (regset == NULL)
193 		return (EINVAL);
194 
195 	if (iov->iov_base == NULL) {
196 		iov->iov_len = regset->size;
197 		if (iov->iov_len == 0)
198 			return (EINVAL);
199 
200 		return (0);
201 	}
202 
203 	/* The length is wrong, return an error */
204 	if (iov->iov_len != regset->size)
205 		return (EINVAL);
206 
207 	if (regset->get == NULL)
208 		return (EINVAL);
209 
210 	error = 0;
211 	size = regset->size;
212 	p = td->td_proc;
213 
214 	/* Drop the proc lock while allocating the temp buffer */
215 	PROC_ASSERT_TRACEREQ(p);
216 	PROC_UNLOCK(p);
217 	buf = malloc(size, M_TEMP, M_WAITOK);
218 	PROC_LOCK(p);
219 
220 	if (!regset->get(regset, td, buf, &size)) {
221 		error = EINVAL;
222 	} else {
223 		KASSERT(size == regset->size,
224 		    ("%s: Getter function changed the size", __func__));
225 
226 		iov->iov_len = size;
227 		PROC_UNLOCK(p);
228 		error = copyout(buf, iov->iov_base, size);
229 		PROC_LOCK(p);
230 	}
231 
232 	free(buf, M_TEMP);
233 
234 	return (error);
235 }
236 
237 static int
238 proc_write_regset(struct thread *td, int note, struct iovec *iov)
239 {
240 	struct regset *regset;
241 	struct proc *p;
242 	void *buf;
243 	size_t size;
244 	int error;
245 
246 	regset = proc_find_regset(td, note);
247 	if (regset == NULL)
248 		return (EINVAL);
249 
250 	/* The length is wrong, return an error */
251 	if (iov->iov_len != regset->size)
252 		return (EINVAL);
253 
254 	if (regset->set == NULL)
255 		return (EINVAL);
256 
257 	size = regset->size;
258 	p = td->td_proc;
259 
260 	/* Drop the proc lock while allocating the temp buffer */
261 	PROC_ASSERT_TRACEREQ(p);
262 	PROC_UNLOCK(p);
263 	buf = malloc(size, M_TEMP, M_WAITOK);
264 	error = copyin(iov->iov_base, buf, size);
265 	PROC_LOCK(p);
266 
267 	if (error == 0) {
268 		if (!regset->set(regset, td, buf, size)) {
269 			error = EINVAL;
270 		}
271 	}
272 
273 	free(buf, M_TEMP);
274 
275 	return (error);
276 }
277 
278 #ifdef COMPAT_FREEBSD32
279 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
280 int
281 proc_read_regs32(struct thread *td, struct reg32 *regs32)
282 {
283 
284 	PROC_ACTION(fill_regs32(td, regs32));
285 }
286 
287 int
288 proc_write_regs32(struct thread *td, struct reg32 *regs32)
289 {
290 
291 	PROC_ACTION(set_regs32(td, regs32));
292 }
293 
294 int
295 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
296 {
297 
298 	PROC_ACTION(fill_dbregs32(td, dbregs32));
299 }
300 
301 int
302 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
303 {
304 
305 	PROC_ACTION(set_dbregs32(td, dbregs32));
306 }
307 
308 int
309 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
310 {
311 
312 	PROC_ACTION(fill_fpregs32(td, fpregs32));
313 }
314 
315 int
316 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
317 {
318 
319 	PROC_ACTION(set_fpregs32(td, fpregs32));
320 }
321 #endif
322 
323 int
324 proc_sstep(struct thread *td)
325 {
326 
327 	PROC_ACTION(ptrace_single_step(td));
328 }
329 
330 int
331 proc_rwmem(struct proc *p, struct uio *uio)
332 {
333 	vm_map_t map;
334 	vm_offset_t pageno;		/* page number */
335 	vm_prot_t reqprot;
336 	int error, fault_flags, page_offset, writing;
337 
338 	/*
339 	 * Make sure that the process' vmspace remains live.
340 	 */
341 	if (p != curproc)
342 		PROC_ASSERT_HELD(p);
343 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
344 
345 	/*
346 	 * The map we want...
347 	 */
348 	map = &p->p_vmspace->vm_map;
349 
350 	/*
351 	 * If we are writing, then we request vm_fault() to create a private
352 	 * copy of each page.  Since these copies will not be writeable by the
353 	 * process, we must explicity request that they be dirtied.
354 	 */
355 	writing = uio->uio_rw == UIO_WRITE;
356 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
357 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
358 
359 	/*
360 	 * Only map in one page at a time.  We don't have to, but it
361 	 * makes things easier.  This way is trivial - right?
362 	 */
363 	do {
364 		vm_offset_t uva;
365 		u_int len;
366 		vm_page_t m;
367 
368 		uva = (vm_offset_t)uio->uio_offset;
369 
370 		/*
371 		 * Get the page number of this segment.
372 		 */
373 		pageno = trunc_page(uva);
374 		page_offset = uva - pageno;
375 
376 		/*
377 		 * How many bytes to copy
378 		 */
379 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
380 
381 		/*
382 		 * Fault and hold the page on behalf of the process.
383 		 */
384 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
385 		if (error != KERN_SUCCESS) {
386 			if (error == KERN_RESOURCE_SHORTAGE)
387 				error = ENOMEM;
388 			else
389 				error = EFAULT;
390 			break;
391 		}
392 
393 		/*
394 		 * Now do the i/o move.
395 		 */
396 		error = uiomove_fromphys(&m, page_offset, len, uio);
397 
398 		/* Make the I-cache coherent for breakpoints. */
399 		if (writing && error == 0) {
400 			vm_map_lock_read(map);
401 			if (vm_map_check_protection(map, pageno, pageno +
402 			    PAGE_SIZE, VM_PROT_EXECUTE))
403 				vm_sync_icache(map, uva, len);
404 			vm_map_unlock_read(map);
405 		}
406 
407 		/*
408 		 * Release the page.
409 		 */
410 		vm_page_unwire(m, PQ_ACTIVE);
411 
412 	} while (error == 0 && uio->uio_resid > 0);
413 
414 	return (error);
415 }
416 
417 static ssize_t
418 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
419     size_t len, enum uio_rw rw)
420 {
421 	struct iovec iov;
422 	struct uio uio;
423 	ssize_t slen;
424 
425 	MPASS(len < SSIZE_MAX);
426 	slen = (ssize_t)len;
427 
428 	iov.iov_base = (caddr_t)buf;
429 	iov.iov_len = len;
430 	uio.uio_iov = &iov;
431 	uio.uio_iovcnt = 1;
432 	uio.uio_offset = va;
433 	uio.uio_resid = slen;
434 	uio.uio_segflg = UIO_SYSSPACE;
435 	uio.uio_rw = rw;
436 	uio.uio_td = td;
437 	proc_rwmem(p, &uio);
438 	if (uio.uio_resid == slen)
439 		return (-1);
440 	return (slen - uio.uio_resid);
441 }
442 
443 ssize_t
444 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
445     size_t len)
446 {
447 
448 	return (proc_iop(td, p, va, buf, len, UIO_READ));
449 }
450 
451 ssize_t
452 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
453     size_t len)
454 {
455 
456 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
457 }
458 
459 static int
460 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
461 {
462 	struct vattr vattr;
463 	vm_map_t map;
464 	vm_map_entry_t entry;
465 	vm_object_t obj, tobj, lobj;
466 	struct vmspace *vm;
467 	struct vnode *vp;
468 	char *freepath, *fullpath;
469 	u_int pathlen;
470 	int error, index;
471 
472 	error = 0;
473 	obj = NULL;
474 
475 	vm = vmspace_acquire_ref(p);
476 	map = &vm->vm_map;
477 	vm_map_lock_read(map);
478 
479 	do {
480 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
481 		    ("Submap in map header"));
482 		index = 0;
483 		VM_MAP_ENTRY_FOREACH(entry, map) {
484 			if (index >= pve->pve_entry &&
485 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
486 				break;
487 			index++;
488 		}
489 		if (index < pve->pve_entry) {
490 			error = EINVAL;
491 			break;
492 		}
493 		if (entry == &map->header) {
494 			error = ENOENT;
495 			break;
496 		}
497 
498 		/* We got an entry. */
499 		pve->pve_entry = index + 1;
500 		pve->pve_timestamp = map->timestamp;
501 		pve->pve_start = entry->start;
502 		pve->pve_end = entry->end - 1;
503 		pve->pve_offset = entry->offset;
504 		pve->pve_prot = entry->protection;
505 
506 		/* Backing object's path needed? */
507 		if (pve->pve_pathlen == 0)
508 			break;
509 
510 		pathlen = pve->pve_pathlen;
511 		pve->pve_pathlen = 0;
512 
513 		obj = entry->object.vm_object;
514 		if (obj != NULL)
515 			VM_OBJECT_RLOCK(obj);
516 	} while (0);
517 
518 	vm_map_unlock_read(map);
519 
520 	pve->pve_fsid = VNOVAL;
521 	pve->pve_fileid = VNOVAL;
522 
523 	if (error == 0 && obj != NULL) {
524 		lobj = obj;
525 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
526 			if (tobj != obj)
527 				VM_OBJECT_RLOCK(tobj);
528 			if (lobj != obj)
529 				VM_OBJECT_RUNLOCK(lobj);
530 			lobj = tobj;
531 			pve->pve_offset += tobj->backing_object_offset;
532 		}
533 		vp = vm_object_vnode(lobj);
534 		if (vp != NULL)
535 			vref(vp);
536 		if (lobj != obj)
537 			VM_OBJECT_RUNLOCK(lobj);
538 		VM_OBJECT_RUNLOCK(obj);
539 
540 		if (vp != NULL) {
541 			freepath = NULL;
542 			fullpath = NULL;
543 			vn_fullpath(vp, &fullpath, &freepath);
544 			vn_lock(vp, LK_SHARED | LK_RETRY);
545 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
546 				pve->pve_fileid = vattr.va_fileid;
547 				pve->pve_fsid = vattr.va_fsid;
548 			}
549 			vput(vp);
550 
551 			if (fullpath != NULL) {
552 				pve->pve_pathlen = strlen(fullpath) + 1;
553 				if (pve->pve_pathlen <= pathlen) {
554 					error = copyout(fullpath, pve->pve_path,
555 					    pve->pve_pathlen);
556 				} else
557 					error = ENAMETOOLONG;
558 			}
559 			if (freepath != NULL)
560 				free(freepath, M_TEMP);
561 		}
562 	}
563 	vmspace_free(vm);
564 	if (error == 0)
565 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
566 		    p->p_pid, pve->pve_entry, pve->pve_start);
567 
568 	return (error);
569 }
570 
571 /*
572  * Process debugging system call.
573  */
574 #ifndef _SYS_SYSPROTO_H_
575 struct ptrace_args {
576 	int	req;
577 	pid_t	pid;
578 	caddr_t	addr;
579 	int	data;
580 };
581 #endif
582 
583 int
584 sys_ptrace(struct thread *td, struct ptrace_args *uap)
585 {
586 	/*
587 	 * XXX this obfuscation is to reduce stack usage, but the register
588 	 * structs may be too large to put on the stack anyway.
589 	 */
590 	union {
591 		struct ptrace_io_desc piod;
592 		struct ptrace_lwpinfo pl;
593 		struct ptrace_vm_entry pve;
594 		struct ptrace_coredump pc;
595 		struct ptrace_sc_remote sr;
596 		struct dbreg dbreg;
597 		struct fpreg fpreg;
598 		struct reg reg;
599 		struct iovec vec;
600 		syscallarg_t args[nitems(td->td_sa.args)];
601 		struct ptrace_sc_ret psr;
602 		int ptevents;
603 	} r;
604 	syscallarg_t pscr_args[nitems(td->td_sa.args)];
605 	void *addr;
606 	int error;
607 
608 	if (!allow_ptrace)
609 		return (ENOSYS);
610 	error = 0;
611 
612 	AUDIT_ARG_PID(uap->pid);
613 	AUDIT_ARG_CMD(uap->req);
614 	AUDIT_ARG_VALUE(uap->data);
615 	addr = &r;
616 	switch (uap->req) {
617 	case PT_GET_EVENT_MASK:
618 	case PT_LWPINFO:
619 	case PT_GET_SC_ARGS:
620 	case PT_GET_SC_RET:
621 		break;
622 	case PT_GETREGS:
623 		bzero(&r.reg, sizeof(r.reg));
624 		break;
625 	case PT_GETFPREGS:
626 		bzero(&r.fpreg, sizeof(r.fpreg));
627 		break;
628 	case PT_GETDBREGS:
629 		bzero(&r.dbreg, sizeof(r.dbreg));
630 		break;
631 	case PT_GETREGSET:
632 	case PT_SETREGSET:
633 		error = copyin(uap->addr, &r.vec, sizeof(r.vec));
634 		break;
635 	case PT_SETREGS:
636 		error = copyin(uap->addr, &r.reg, sizeof(r.reg));
637 		break;
638 	case PT_SETFPREGS:
639 		error = copyin(uap->addr, &r.fpreg, sizeof(r.fpreg));
640 		break;
641 	case PT_SETDBREGS:
642 		error = copyin(uap->addr, &r.dbreg, sizeof(r.dbreg));
643 		break;
644 	case PT_SET_EVENT_MASK:
645 		if (uap->data != sizeof(r.ptevents))
646 			error = EINVAL;
647 		else
648 			error = copyin(uap->addr, &r.ptevents, uap->data);
649 		break;
650 	case PT_IO:
651 		error = copyin(uap->addr, &r.piod, sizeof(r.piod));
652 		break;
653 	case PT_VM_ENTRY:
654 		error = copyin(uap->addr, &r.pve, sizeof(r.pve));
655 		break;
656 	case PT_COREDUMP:
657 		if (uap->data != sizeof(r.pc))
658 			error = EINVAL;
659 		else
660 			error = copyin(uap->addr, &r.pc, uap->data);
661 		break;
662 	case PT_SC_REMOTE:
663 		if (uap->data != sizeof(r.sr)) {
664 			error = EINVAL;
665 			break;
666 		}
667 		error = copyin(uap->addr, &r.sr, uap->data);
668 		if (error != 0)
669 			break;
670 		if (r.sr.pscr_nargs > nitems(td->td_sa.args)) {
671 			error = EINVAL;
672 			break;
673 		}
674 		error = copyin(r.sr.pscr_args, pscr_args,
675 		    sizeof(u_long) * r.sr.pscr_nargs);
676 		if (error != 0)
677 			break;
678 		r.sr.pscr_args = pscr_args;
679 		break;
680 	default:
681 		addr = uap->addr;
682 		break;
683 	}
684 	if (error)
685 		return (error);
686 
687 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
688 	if (error)
689 		return (error);
690 
691 	switch (uap->req) {
692 	case PT_VM_ENTRY:
693 		error = copyout(&r.pve, uap->addr, sizeof(r.pve));
694 		break;
695 	case PT_IO:
696 		error = copyout(&r.piod, uap->addr, sizeof(r.piod));
697 		break;
698 	case PT_GETREGS:
699 		error = copyout(&r.reg, uap->addr, sizeof(r.reg));
700 		break;
701 	case PT_GETFPREGS:
702 		error = copyout(&r.fpreg, uap->addr, sizeof(r.fpreg));
703 		break;
704 	case PT_GETDBREGS:
705 		error = copyout(&r.dbreg, uap->addr, sizeof(r.dbreg));
706 		break;
707 	case PT_GETREGSET:
708 		error = copyout(&r.vec, uap->addr, sizeof(r.vec));
709 		break;
710 	case PT_GET_EVENT_MASK:
711 		/* NB: The size in uap->data is validated in kern_ptrace(). */
712 		error = copyout(&r.ptevents, uap->addr, uap->data);
713 		break;
714 	case PT_LWPINFO:
715 		/* NB: The size in uap->data is validated in kern_ptrace(). */
716 		error = copyout(&r.pl, uap->addr, uap->data);
717 		break;
718 	case PT_GET_SC_ARGS:
719 		error = copyout(r.args, uap->addr, MIN(uap->data,
720 		    sizeof(r.args)));
721 		break;
722 	case PT_GET_SC_RET:
723 		error = copyout(&r.psr, uap->addr, MIN(uap->data,
724 		    sizeof(r.psr)));
725 		break;
726 	case PT_SC_REMOTE:
727 		error = copyout(&r.sr.pscr_ret, uap->addr +
728 		    offsetof(struct ptrace_sc_remote, pscr_ret),
729 		    sizeof(r.sr.pscr_ret));
730 		break;
731 	}
732 
733 	return (error);
734 }
735 
736 #ifdef COMPAT_FREEBSD32
737 /*
738  *   PROC_READ(regs, td2, addr);
739  * becomes either:
740  *   proc_read_regs(td2, addr);
741  * or
742  *   proc_read_regs32(td2, addr);
743  * .. except this is done at runtime.  There is an additional
744  * complication in that PROC_WRITE disallows 32 bit consumers
745  * from writing to 64 bit address space targets.
746  */
747 #define	PROC_READ(w, t, a)	wrap32 ? \
748 	proc_read_ ## w ## 32(t, a) : \
749 	proc_read_ ## w (t, a)
750 #define	PROC_WRITE(w, t, a)	wrap32 ? \
751 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
752 	proc_write_ ## w (t, a)
753 #else
754 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
755 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
756 #endif
757 
758 void
759 proc_set_traced(struct proc *p, bool stop)
760 {
761 
762 	sx_assert(&proctree_lock, SX_XLOCKED);
763 	PROC_LOCK_ASSERT(p, MA_OWNED);
764 	p->p_flag |= P_TRACED;
765 	if (stop)
766 		p->p_flag2 |= P2_PTRACE_FSTP;
767 	p->p_ptevents = PTRACE_DEFAULT;
768 }
769 
770 void
771 ptrace_unsuspend(struct proc *p)
772 {
773 	PROC_LOCK_ASSERT(p, MA_OWNED);
774 
775 	PROC_SLOCK(p);
776 	p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
777 	thread_unsuspend(p);
778 	PROC_SUNLOCK(p);
779 	itimer_proc_continue(p);
780 	kqtimer_proc_continue(p);
781 }
782 
783 static int
784 proc_can_ptrace(struct thread *td, struct proc *p)
785 {
786 	int error;
787 
788 	PROC_LOCK_ASSERT(p, MA_OWNED);
789 
790 	if ((p->p_flag & P_WEXIT) != 0)
791 		return (ESRCH);
792 
793 	if ((error = p_cansee(td, p)) != 0)
794 		return (error);
795 	if ((error = p_candebug(td, p)) != 0)
796 		return (error);
797 
798 	/* not being traced... */
799 	if ((p->p_flag & P_TRACED) == 0)
800 		return (EPERM);
801 
802 	/* not being traced by YOU */
803 	if (p->p_pptr != td->td_proc)
804 		return (EBUSY);
805 
806 	/* not currently stopped */
807 	if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
808 	    p->p_suspcount != p->p_numthreads  ||
809 	    (p->p_flag & P_WAITED) == 0)
810 		return (EBUSY);
811 
812 	return (0);
813 }
814 
815 static struct thread *
816 ptrace_sel_coredump_thread(struct proc *p)
817 {
818 	struct thread *td2;
819 
820 	PROC_LOCK_ASSERT(p, MA_OWNED);
821 	MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
822 
823 	FOREACH_THREAD_IN_PROC(p, td2) {
824 		if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
825 			return (td2);
826 	}
827 	return (NULL);
828 }
829 
830 int
831 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
832 {
833 	struct iovec iov;
834 	struct uio uio;
835 	struct proc *curp, *p, *pp;
836 	struct thread *td2 = NULL, *td3;
837 	struct ptrace_io_desc *piod = NULL;
838 	struct ptrace_lwpinfo *pl;
839 	struct ptrace_sc_ret *psr;
840 	struct ptrace_sc_remote *pscr;
841 	struct file *fp;
842 	struct ptrace_coredump *pc;
843 	struct thr_coredump_req *tcq;
844 	struct thr_syscall_req *tsr;
845 	int error, num, tmp;
846 	lwpid_t tid = 0, *buf;
847 #ifdef COMPAT_FREEBSD32
848 	int wrap32 = 0, safe = 0;
849 #endif
850 	bool proctree_locked, p2_req_set;
851 
852 	curp = td->td_proc;
853 	proctree_locked = false;
854 	p2_req_set = false;
855 
856 	/* Lock proctree before locking the process. */
857 	switch (req) {
858 	case PT_TRACE_ME:
859 	case PT_ATTACH:
860 	case PT_STEP:
861 	case PT_CONTINUE:
862 	case PT_TO_SCE:
863 	case PT_TO_SCX:
864 	case PT_SYSCALL:
865 	case PT_FOLLOW_FORK:
866 	case PT_LWP_EVENTS:
867 	case PT_GET_EVENT_MASK:
868 	case PT_SET_EVENT_MASK:
869 	case PT_DETACH:
870 	case PT_GET_SC_ARGS:
871 		sx_xlock(&proctree_lock);
872 		proctree_locked = true;
873 		break;
874 	default:
875 		break;
876 	}
877 
878 	if (req == PT_TRACE_ME) {
879 		p = td->td_proc;
880 		PROC_LOCK(p);
881 	} else {
882 		if (pid <= PID_MAX) {
883 			if ((p = pfind(pid)) == NULL) {
884 				if (proctree_locked)
885 					sx_xunlock(&proctree_lock);
886 				return (ESRCH);
887 			}
888 		} else {
889 			td2 = tdfind(pid, -1);
890 			if (td2 == NULL) {
891 				if (proctree_locked)
892 					sx_xunlock(&proctree_lock);
893 				return (ESRCH);
894 			}
895 			p = td2->td_proc;
896 			tid = pid;
897 			pid = p->p_pid;
898 		}
899 	}
900 	AUDIT_ARG_PROCESS(p);
901 
902 	if ((p->p_flag & P_WEXIT) != 0) {
903 		error = ESRCH;
904 		goto fail;
905 	}
906 	if ((error = p_cansee(td, p)) != 0)
907 		goto fail;
908 
909 	if ((error = p_candebug(td, p)) != 0)
910 		goto fail;
911 
912 	/*
913 	 * System processes can't be debugged.
914 	 */
915 	if ((p->p_flag & P_SYSTEM) != 0) {
916 		error = EINVAL;
917 		goto fail;
918 	}
919 
920 	if (tid == 0) {
921 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
922 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
923 			td2 = p->p_xthread;
924 		} else {
925 			td2 = FIRST_THREAD_IN_PROC(p);
926 		}
927 		tid = td2->td_tid;
928 	}
929 
930 #ifdef COMPAT_FREEBSD32
931 	/*
932 	 * Test if we're a 32 bit client and what the target is.
933 	 * Set the wrap controls accordingly.
934 	 */
935 	if (SV_CURPROC_FLAG(SV_ILP32)) {
936 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
937 			safe = 1;
938 		wrap32 = 1;
939 	}
940 #endif
941 	/*
942 	 * Permissions check
943 	 */
944 	switch (req) {
945 	case PT_TRACE_ME:
946 		/*
947 		 * Always legal, when there is a parent process which
948 		 * could trace us.  Otherwise, reject.
949 		 */
950 		if ((p->p_flag & P_TRACED) != 0) {
951 			error = EBUSY;
952 			goto fail;
953 		}
954 		if (p->p_pptr == initproc) {
955 			error = EPERM;
956 			goto fail;
957 		}
958 		break;
959 
960 	case PT_ATTACH:
961 		/* Self */
962 		if (p == td->td_proc) {
963 			error = EINVAL;
964 			goto fail;
965 		}
966 
967 		/* Already traced */
968 		if (p->p_flag & P_TRACED) {
969 			error = EBUSY;
970 			goto fail;
971 		}
972 
973 		/* Can't trace an ancestor if you're being traced. */
974 		if (curp->p_flag & P_TRACED) {
975 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
976 				if (pp == p) {
977 					error = EINVAL;
978 					goto fail;
979 				}
980 			}
981 		}
982 
983 		/* OK */
984 		break;
985 
986 	case PT_CLEARSTEP:
987 		/* Allow thread to clear single step for itself */
988 		if (td->td_tid == tid)
989 			break;
990 
991 		/* FALLTHROUGH */
992 	default:
993 		/*
994 		 * Check for ptrace eligibility before waiting for
995 		 * holds to drain.
996 		 */
997 		error = proc_can_ptrace(td, p);
998 		if (error != 0)
999 			goto fail;
1000 
1001 		/*
1002 		 * Block parallel ptrace requests.  Most important, do
1003 		 * not allow other thread in debugger to continue the
1004 		 * debuggee until coredump finished.
1005 		 */
1006 		while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
1007 			if (proctree_locked)
1008 				sx_xunlock(&proctree_lock);
1009 			error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
1010 			    (proctree_locked ? PDROP : 0), "pptrace", 0);
1011 			if (proctree_locked) {
1012 				sx_xlock(&proctree_lock);
1013 				PROC_LOCK(p);
1014 			}
1015 			if (error == 0 && td2->td_proc != p)
1016 				error = ESRCH;
1017 			if (error == 0)
1018 				error = proc_can_ptrace(td, p);
1019 			if (error != 0)
1020 				goto fail;
1021 		}
1022 
1023 		/* Ok */
1024 		break;
1025 	}
1026 
1027 	/*
1028 	 * Keep this process around and request parallel ptrace()
1029 	 * request to wait until we finish this request.
1030 	 */
1031 	MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
1032 	p->p_flag2 |= P2_PTRACEREQ;
1033 	p2_req_set = true;
1034 	_PHOLD(p);
1035 
1036 	/*
1037 	 * Actually do the requests
1038 	 */
1039 
1040 	td->td_retval[0] = 0;
1041 
1042 	switch (req) {
1043 	case PT_TRACE_ME:
1044 		/* set my trace flag and "owner" so it can read/write me */
1045 		proc_set_traced(p, false);
1046 		if (p->p_flag & P_PPWAIT)
1047 			p->p_flag |= P_PPTRACE;
1048 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
1049 		break;
1050 
1051 	case PT_ATTACH:
1052 		/* security check done above */
1053 		/*
1054 		 * It would be nice if the tracing relationship was separate
1055 		 * from the parent relationship but that would require
1056 		 * another set of links in the proc struct or for "wait"
1057 		 * to scan the entire proc table.  To make life easier,
1058 		 * we just re-parent the process we're trying to trace.
1059 		 * The old parent is remembered so we can put things back
1060 		 * on a "detach".
1061 		 */
1062 		proc_set_traced(p, true);
1063 		proc_reparent(p, td->td_proc, false);
1064 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
1065 		    p->p_oppid);
1066 
1067 		sx_xunlock(&proctree_lock);
1068 		proctree_locked = false;
1069 		MPASS(p->p_xthread == NULL);
1070 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
1071 
1072 		/*
1073 		 * If already stopped due to a stop signal, clear the
1074 		 * existing stop before triggering a traced SIGSTOP.
1075 		 */
1076 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
1077 			PROC_SLOCK(p);
1078 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
1079 			thread_unsuspend(p);
1080 			PROC_SUNLOCK(p);
1081 		}
1082 
1083 		kern_psignal(p, SIGSTOP);
1084 		break;
1085 
1086 	case PT_CLEARSTEP:
1087 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
1088 		    p->p_pid);
1089 		error = ptrace_clear_single_step(td2);
1090 		break;
1091 
1092 	case PT_SETSTEP:
1093 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
1094 		    p->p_pid);
1095 		error = ptrace_single_step(td2);
1096 		break;
1097 
1098 	case PT_SUSPEND:
1099 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
1100 		    p->p_pid);
1101 		td2->td_dbgflags |= TDB_SUSPEND;
1102 		ast_sched(td2, TDA_SUSPEND);
1103 		break;
1104 
1105 	case PT_RESUME:
1106 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
1107 		    p->p_pid);
1108 		td2->td_dbgflags &= ~TDB_SUSPEND;
1109 		break;
1110 
1111 	case PT_FOLLOW_FORK:
1112 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
1113 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
1114 		    data ? "enabled" : "disabled");
1115 		if (data)
1116 			p->p_ptevents |= PTRACE_FORK;
1117 		else
1118 			p->p_ptevents &= ~PTRACE_FORK;
1119 		break;
1120 
1121 	case PT_LWP_EVENTS:
1122 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
1123 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
1124 		    data ? "enabled" : "disabled");
1125 		if (data)
1126 			p->p_ptevents |= PTRACE_LWP;
1127 		else
1128 			p->p_ptevents &= ~PTRACE_LWP;
1129 		break;
1130 
1131 	case PT_GET_EVENT_MASK:
1132 		if (data != sizeof(p->p_ptevents)) {
1133 			error = EINVAL;
1134 			break;
1135 		}
1136 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1137 		    p->p_ptevents);
1138 		*(int *)addr = p->p_ptevents;
1139 		break;
1140 
1141 	case PT_SET_EVENT_MASK:
1142 		if (data != sizeof(p->p_ptevents)) {
1143 			error = EINVAL;
1144 			break;
1145 		}
1146 		tmp = *(int *)addr;
1147 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1148 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1149 			error = EINVAL;
1150 			break;
1151 		}
1152 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1153 		    p->p_pid, p->p_ptevents, tmp);
1154 		p->p_ptevents = tmp;
1155 		break;
1156 
1157 	case PT_GET_SC_ARGS:
1158 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1159 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1160 #ifdef COMPAT_FREEBSD32
1161 		    || (wrap32 && !safe)
1162 #endif
1163 		    ) {
1164 			error = EINVAL;
1165 			break;
1166 		}
1167 		bzero(addr, sizeof(td2->td_sa.args));
1168 		/* See the explanation in linux_ptrace_get_syscall_info(). */
1169 		bcopy(td2->td_sa.args, addr, SV_PROC_ABI(td->td_proc) ==
1170 		    SV_ABI_LINUX ? sizeof(td2->td_sa.args) :
1171 		    td2->td_sa.callp->sy_narg * sizeof(syscallarg_t));
1172 		break;
1173 
1174 	case PT_GET_SC_RET:
1175 		if ((td2->td_dbgflags & (TDB_SCX)) == 0
1176 #ifdef COMPAT_FREEBSD32
1177 		    || (wrap32 && !safe)
1178 #endif
1179 		    ) {
1180 			error = EINVAL;
1181 			break;
1182 		}
1183 		psr = addr;
1184 		bzero(psr, sizeof(*psr));
1185 		psr->sr_error = td2->td_errno;
1186 		if (psr->sr_error == 0) {
1187 			psr->sr_retval[0] = td2->td_retval[0];
1188 			psr->sr_retval[1] = td2->td_retval[1];
1189 		}
1190 		CTR4(KTR_PTRACE,
1191 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1192 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1193 		    psr->sr_retval[1]);
1194 		break;
1195 
1196 	case PT_STEP:
1197 	case PT_CONTINUE:
1198 	case PT_TO_SCE:
1199 	case PT_TO_SCX:
1200 	case PT_SYSCALL:
1201 	case PT_DETACH:
1202 		/* Zero means do not send any signal */
1203 		if (data < 0 || data > _SIG_MAXSIG) {
1204 			error = EINVAL;
1205 			break;
1206 		}
1207 
1208 		switch (req) {
1209 		case PT_STEP:
1210 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1211 			    td2->td_tid, p->p_pid, data);
1212 			error = ptrace_single_step(td2);
1213 			if (error)
1214 				goto out;
1215 			break;
1216 		case PT_CONTINUE:
1217 		case PT_TO_SCE:
1218 		case PT_TO_SCX:
1219 		case PT_SYSCALL:
1220 			if (addr != (void *)1) {
1221 				error = ptrace_set_pc(td2,
1222 				    (u_long)(uintfptr_t)addr);
1223 				if (error)
1224 					goto out;
1225 			}
1226 			switch (req) {
1227 			case PT_TO_SCE:
1228 				p->p_ptevents |= PTRACE_SCE;
1229 				CTR4(KTR_PTRACE,
1230 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1231 				    p->p_pid, p->p_ptevents,
1232 				    (u_long)(uintfptr_t)addr, data);
1233 				break;
1234 			case PT_TO_SCX:
1235 				p->p_ptevents |= PTRACE_SCX;
1236 				CTR4(KTR_PTRACE,
1237 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1238 				    p->p_pid, p->p_ptevents,
1239 				    (u_long)(uintfptr_t)addr, data);
1240 				break;
1241 			case PT_SYSCALL:
1242 				p->p_ptevents |= PTRACE_SYSCALL;
1243 				CTR4(KTR_PTRACE,
1244 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1245 				    p->p_pid, p->p_ptevents,
1246 				    (u_long)(uintfptr_t)addr, data);
1247 				break;
1248 			case PT_CONTINUE:
1249 				CTR3(KTR_PTRACE,
1250 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1251 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1252 				break;
1253 			}
1254 			break;
1255 		case PT_DETACH:
1256 			/*
1257 			 * Clear P_TRACED before reparenting
1258 			 * a detached process back to its original
1259 			 * parent.  Otherwise the debugee will be set
1260 			 * as an orphan of the debugger.
1261 			 */
1262 			p->p_flag &= ~(P_TRACED | P_WAITED);
1263 
1264 			/*
1265 			 * Reset the process parent.
1266 			 */
1267 			if (p->p_oppid != p->p_pptr->p_pid) {
1268 				PROC_LOCK(p->p_pptr);
1269 				sigqueue_take(p->p_ksi);
1270 				PROC_UNLOCK(p->p_pptr);
1271 
1272 				pp = proc_realparent(p);
1273 				proc_reparent(p, pp, false);
1274 				if (pp == initproc)
1275 					p->p_sigparent = SIGCHLD;
1276 				CTR3(KTR_PTRACE,
1277 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1278 				    p->p_pid, pp->p_pid, data);
1279 			} else {
1280 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1281 				    p->p_pid, data);
1282 			}
1283 
1284 			p->p_ptevents = 0;
1285 			FOREACH_THREAD_IN_PROC(p, td3) {
1286 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1287 					sigqueue_delete(&td3->td_sigqueue,
1288 					    SIGSTOP);
1289 				}
1290 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1291 				    TDB_SUSPEND | TDB_BORN);
1292 			}
1293 
1294 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1295 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1296 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1297 			}
1298 
1299 			/* should we send SIGCHLD? */
1300 			/* childproc_continued(p); */
1301 			break;
1302 		}
1303 
1304 		sx_xunlock(&proctree_lock);
1305 		proctree_locked = false;
1306 
1307 	sendsig:
1308 		MPASS(!proctree_locked);
1309 
1310 		/*
1311 		 * Clear the pending event for the thread that just
1312 		 * reported its event (p_xthread).  This may not be
1313 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1314 		 * the debugger is resuming a different thread.
1315 		 *
1316 		 * Deliver any pending signal via the reporting thread.
1317 		 */
1318 		MPASS(p->p_xthread != NULL);
1319 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1320 		p->p_xthread->td_xsig = data;
1321 		p->p_xthread = NULL;
1322 		p->p_xsig = data;
1323 
1324 		/*
1325 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1326 		 * always works immediately, even if another thread is
1327 		 * unsuspended first and attempts to handle a
1328 		 * different signal or if the POSIX.1b style signal
1329 		 * queue cannot accommodate any new signals.
1330 		 */
1331 		if (data == SIGKILL)
1332 			proc_wkilled(p);
1333 
1334 		/*
1335 		 * Unsuspend all threads.  To leave a thread
1336 		 * suspended, use PT_SUSPEND to suspend it before
1337 		 * continuing the process.
1338 		 */
1339 		ptrace_unsuspend(p);
1340 		break;
1341 
1342 	case PT_WRITE_I:
1343 	case PT_WRITE_D:
1344 		td2->td_dbgflags |= TDB_USERWR;
1345 		PROC_UNLOCK(p);
1346 		error = 0;
1347 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1348 		    sizeof(int)) != sizeof(int))
1349 			error = ENOMEM;
1350 		else
1351 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1352 			    p->p_pid, addr, data);
1353 		PROC_LOCK(p);
1354 		break;
1355 
1356 	case PT_READ_I:
1357 	case PT_READ_D:
1358 		PROC_UNLOCK(p);
1359 		error = tmp = 0;
1360 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1361 		    sizeof(int)) != sizeof(int))
1362 			error = ENOMEM;
1363 		else
1364 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1365 			    p->p_pid, addr, tmp);
1366 		td->td_retval[0] = tmp;
1367 		PROC_LOCK(p);
1368 		break;
1369 
1370 	case PT_IO:
1371 		piod = addr;
1372 		iov.iov_base = piod->piod_addr;
1373 		iov.iov_len = piod->piod_len;
1374 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1375 		uio.uio_resid = piod->piod_len;
1376 		uio.uio_iov = &iov;
1377 		uio.uio_iovcnt = 1;
1378 		uio.uio_segflg = UIO_USERSPACE;
1379 		uio.uio_td = td;
1380 		switch (piod->piod_op) {
1381 		case PIOD_READ_D:
1382 		case PIOD_READ_I:
1383 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1384 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1385 			uio.uio_rw = UIO_READ;
1386 			break;
1387 		case PIOD_WRITE_D:
1388 		case PIOD_WRITE_I:
1389 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1390 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1391 			td2->td_dbgflags |= TDB_USERWR;
1392 			uio.uio_rw = UIO_WRITE;
1393 			break;
1394 		default:
1395 			error = EINVAL;
1396 			goto out;
1397 		}
1398 		PROC_UNLOCK(p);
1399 		error = proc_rwmem(p, &uio);
1400 		piod->piod_len -= uio.uio_resid;
1401 		PROC_LOCK(p);
1402 		break;
1403 
1404 	case PT_KILL:
1405 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1406 		data = SIGKILL;
1407 		goto sendsig;	/* in PT_CONTINUE above */
1408 
1409 	case PT_SETREGS:
1410 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1411 		    p->p_pid);
1412 		td2->td_dbgflags |= TDB_USERWR;
1413 		error = PROC_WRITE(regs, td2, addr);
1414 		break;
1415 
1416 	case PT_GETREGS:
1417 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1418 		    p->p_pid);
1419 		error = PROC_READ(regs, td2, addr);
1420 		break;
1421 
1422 	case PT_SETFPREGS:
1423 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1424 		    p->p_pid);
1425 		td2->td_dbgflags |= TDB_USERWR;
1426 		error = PROC_WRITE(fpregs, td2, addr);
1427 		break;
1428 
1429 	case PT_GETFPREGS:
1430 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1431 		    p->p_pid);
1432 		error = PROC_READ(fpregs, td2, addr);
1433 		break;
1434 
1435 	case PT_SETDBREGS:
1436 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1437 		    p->p_pid);
1438 		td2->td_dbgflags |= TDB_USERWR;
1439 		error = PROC_WRITE(dbregs, td2, addr);
1440 		break;
1441 
1442 	case PT_GETDBREGS:
1443 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1444 		    p->p_pid);
1445 		error = PROC_READ(dbregs, td2, addr);
1446 		break;
1447 
1448 	case PT_SETREGSET:
1449 		CTR2(KTR_PTRACE, "PT_SETREGSET: tid %d (pid %d)", td2->td_tid,
1450 		    p->p_pid);
1451 		error = proc_write_regset(td2, data, addr);
1452 		break;
1453 
1454 	case PT_GETREGSET:
1455 		CTR2(KTR_PTRACE, "PT_GETREGSET: tid %d (pid %d)", td2->td_tid,
1456 		    p->p_pid);
1457 		error = proc_read_regset(td2, data, addr);
1458 		break;
1459 
1460 	case PT_LWPINFO:
1461 		if (data <= 0 || data > sizeof(*pl)) {
1462 			error = EINVAL;
1463 			break;
1464 		}
1465 		pl = addr;
1466 		bzero(pl, sizeof(*pl));
1467 		pl->pl_lwpid = td2->td_tid;
1468 		pl->pl_event = PL_EVENT_NONE;
1469 		pl->pl_flags = 0;
1470 		if (td2->td_dbgflags & TDB_XSIG) {
1471 			pl->pl_event = PL_EVENT_SIGNAL;
1472 			if (td2->td_si.si_signo != 0 &&
1473 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1474 			    + sizeof(pl->pl_siginfo)){
1475 				pl->pl_flags |= PL_FLAG_SI;
1476 				pl->pl_siginfo = td2->td_si;
1477 			}
1478 		}
1479 		if (td2->td_dbgflags & TDB_SCE)
1480 			pl->pl_flags |= PL_FLAG_SCE;
1481 		else if (td2->td_dbgflags & TDB_SCX)
1482 			pl->pl_flags |= PL_FLAG_SCX;
1483 		if (td2->td_dbgflags & TDB_EXEC)
1484 			pl->pl_flags |= PL_FLAG_EXEC;
1485 		if (td2->td_dbgflags & TDB_FORK) {
1486 			pl->pl_flags |= PL_FLAG_FORKED;
1487 			pl->pl_child_pid = td2->td_dbg_forked;
1488 			if (td2->td_dbgflags & TDB_VFORK)
1489 				pl->pl_flags |= PL_FLAG_VFORKED;
1490 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1491 		    TDB_VFORK)
1492 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1493 		if (td2->td_dbgflags & TDB_CHILD)
1494 			pl->pl_flags |= PL_FLAG_CHILD;
1495 		if (td2->td_dbgflags & TDB_BORN)
1496 			pl->pl_flags |= PL_FLAG_BORN;
1497 		if (td2->td_dbgflags & TDB_EXIT)
1498 			pl->pl_flags |= PL_FLAG_EXITED;
1499 		pl->pl_sigmask = td2->td_sigmask;
1500 		pl->pl_siglist = td2->td_siglist;
1501 		strcpy(pl->pl_tdname, td2->td_name);
1502 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1503 			pl->pl_syscall_code = td2->td_sa.code;
1504 			pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1505 		} else {
1506 			pl->pl_syscall_code = 0;
1507 			pl->pl_syscall_narg = 0;
1508 		}
1509 		CTR6(KTR_PTRACE,
1510     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1511 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1512 		    pl->pl_child_pid, pl->pl_syscall_code);
1513 		break;
1514 
1515 	case PT_GETNUMLWPS:
1516 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1517 		    p->p_numthreads);
1518 		td->td_retval[0] = p->p_numthreads;
1519 		break;
1520 
1521 	case PT_GETLWPLIST:
1522 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1523 		    p->p_pid, data, p->p_numthreads);
1524 		if (data <= 0) {
1525 			error = EINVAL;
1526 			break;
1527 		}
1528 		num = imin(p->p_numthreads, data);
1529 		PROC_UNLOCK(p);
1530 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1531 		tmp = 0;
1532 		PROC_LOCK(p);
1533 		FOREACH_THREAD_IN_PROC(p, td2) {
1534 			if (tmp >= num)
1535 				break;
1536 			buf[tmp++] = td2->td_tid;
1537 		}
1538 		PROC_UNLOCK(p);
1539 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1540 		free(buf, M_TEMP);
1541 		if (!error)
1542 			td->td_retval[0] = tmp;
1543 		PROC_LOCK(p);
1544 		break;
1545 
1546 	case PT_VM_TIMESTAMP:
1547 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1548 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1549 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1550 		break;
1551 
1552 	case PT_VM_ENTRY:
1553 		PROC_UNLOCK(p);
1554 		error = ptrace_vm_entry(td, p, addr);
1555 		PROC_LOCK(p);
1556 		break;
1557 
1558 	case PT_COREDUMP:
1559 		pc = addr;
1560 		CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1561 		    p->p_pid, pc->pc_fd);
1562 
1563 		if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1564 			error = EINVAL;
1565 			break;
1566 		}
1567 		PROC_UNLOCK(p);
1568 
1569 		tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1570 		fp = NULL;
1571 		error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1572 		if (error != 0)
1573 			goto coredump_cleanup_nofp;
1574 		if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1575 			error = EPIPE;
1576 			goto coredump_cleanup;
1577 		}
1578 
1579 		PROC_LOCK(p);
1580 		error = proc_can_ptrace(td, p);
1581 		if (error != 0)
1582 			goto coredump_cleanup_locked;
1583 
1584 		td2 = ptrace_sel_coredump_thread(p);
1585 		if (td2 == NULL) {
1586 			error = EBUSY;
1587 			goto coredump_cleanup_locked;
1588 		}
1589 		KASSERT((td2->td_dbgflags & (TDB_COREDUMPREQ |
1590 		    TDB_SCREMOTEREQ)) == 0,
1591 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1592 
1593 		tcq->tc_vp = fp->f_vnode;
1594 		tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1595 		tcq->tc_flags = SVC_PT_COREDUMP;
1596 		if ((pc->pc_flags & PC_COMPRESS) == 0)
1597 			tcq->tc_flags |= SVC_NOCOMPRESS;
1598 		if ((pc->pc_flags & PC_ALL) != 0)
1599 			tcq->tc_flags |= SVC_ALL;
1600 		td2->td_remotereq = tcq;
1601 		td2->td_dbgflags |= TDB_COREDUMPREQ;
1602 		thread_run_flash(td2);
1603 		while ((td2->td_dbgflags & TDB_COREDUMPREQ) != 0)
1604 			msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1605 		error = tcq->tc_error;
1606 coredump_cleanup_locked:
1607 		PROC_UNLOCK(p);
1608 coredump_cleanup:
1609 		fdrop(fp, td);
1610 coredump_cleanup_nofp:
1611 		free(tcq, M_TEMP);
1612 		PROC_LOCK(p);
1613 		break;
1614 
1615 	case PT_SC_REMOTE:
1616 		pscr = addr;
1617 		CTR2(KTR_PTRACE, "PT_SC_REMOTE: pid %d, syscall %d",
1618 		    p->p_pid, pscr->pscr_syscall);
1619 		if ((td2->td_dbgflags & TDB_BOUNDARY) == 0) {
1620 			error = EBUSY;
1621 			break;
1622 		}
1623 		PROC_UNLOCK(p);
1624 		MPASS(pscr->pscr_nargs <= nitems(td->td_sa.args));
1625 
1626 		tsr = malloc(sizeof(struct thr_syscall_req), M_TEMP,
1627 		    M_WAITOK | M_ZERO);
1628 
1629 		tsr->ts_sa.code = pscr->pscr_syscall;
1630 		tsr->ts_nargs = pscr->pscr_nargs;
1631 		memcpy(&tsr->ts_sa.args, pscr->pscr_args,
1632 		    sizeof(syscallarg_t) * tsr->ts_nargs);
1633 
1634 		PROC_LOCK(p);
1635 		error = proc_can_ptrace(td, p);
1636 		if (error != 0) {
1637 			free(tsr, M_TEMP);
1638 			break;
1639 		}
1640 		if (td2->td_proc != p) {
1641 			free(tsr, M_TEMP);
1642 			error = ESRCH;
1643 			break;
1644 		}
1645 		KASSERT((td2->td_dbgflags & (TDB_COREDUMPREQ |
1646 		    TDB_SCREMOTEREQ)) == 0,
1647 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1648 
1649 		td2->td_remotereq = tsr;
1650 		td2->td_dbgflags |= TDB_SCREMOTEREQ;
1651 		thread_run_flash(td2);
1652 		while ((td2->td_dbgflags & TDB_SCREMOTEREQ) != 0)
1653 			msleep(p, &p->p_mtx, PPAUSE, "pscrx", 0);
1654 		error = 0;
1655 		memcpy(&pscr->pscr_ret, &tsr->ts_ret, sizeof(tsr->ts_ret));
1656 		free(tsr, M_TEMP);
1657 		break;
1658 
1659 	default:
1660 #ifdef __HAVE_PTRACE_MACHDEP
1661 		if (req >= PT_FIRSTMACH) {
1662 			PROC_UNLOCK(p);
1663 			error = cpu_ptrace(td2, req, addr, data);
1664 			PROC_LOCK(p);
1665 		} else
1666 #endif
1667 			/* Unknown request. */
1668 			error = EINVAL;
1669 		break;
1670 	}
1671 out:
1672 	/* Drop our hold on this process now that the request has completed. */
1673 	_PRELE(p);
1674 fail:
1675 	if (p2_req_set) {
1676 		if ((p->p_flag2 & P2_PTRACEREQ) != 0)
1677 			wakeup(&p->p_flag2);
1678 		p->p_flag2 &= ~P2_PTRACEREQ;
1679 	}
1680 	PROC_UNLOCK(p);
1681 	if (proctree_locked)
1682 		sx_xunlock(&proctree_lock);
1683 	return (error);
1684 }
1685 #undef PROC_READ
1686 #undef PROC_WRITE
1687