xref: /freebsd/sys/kern/sys_process.c (revision 3dfd63b58463e8982af2e45fc6dc1d5b03a88535)
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/systm.h>
35 #include <sys/capsicum.h>
36 #include <sys/filedesc.h>
37 #include <sys/imgact.h>
38 #include <sys/ktr.h>
39 #include <sys/limits.h>
40 #include <sys/lock.h>
41 #include <sys/malloc.h>
42 #include <sys/mman.h>
43 #include <sys/mutex.h>
44 #include <sys/priv.h>
45 #include <sys/proc.h>
46 #include <sys/procdesc.h>
47 #include <sys/ptrace.h>
48 #include <sys/reg.h>
49 #include <sys/rwlock.h>
50 #include <sys/signalvar.h>
51 #include <sys/sleepqueue.h>
52 #include <sys/sx.h>
53 #include <sys/syscallsubr.h>
54 #include <sys/sysent.h>
55 #include <sys/sysproto.h>
56 #include <sys/vnode.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 below:
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 int
103 proc_read_regs(struct thread *td, struct reg *regs)
104 {
105 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
106 	return (fill_regs(td, regs));
107 }
108 
109 int
110 proc_write_regs(struct thread *td, struct reg *regs)
111 {
112 	int error;
113 
114 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
115 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
116 	if (error != 0)
117 		return (error);
118 	return (set_regs(td, regs));
119 }
120 
121 int
122 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
123 {
124 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
125 	return (fill_dbregs(td, dbregs));
126 }
127 
128 int
129 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
130 {
131 	int error;
132 
133 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
134 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
135 	if (error != 0)
136 		return (error);
137 	return (set_dbregs(td, dbregs));
138 }
139 
140 /*
141  * Ptrace doesn't support fpregs at all, and there are no security holes
142  * or translations for fpregs, so we can just copy them.
143  */
144 int
145 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
146 {
147 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
148 	return (fill_fpregs(td, fpregs));
149 }
150 
151 int
152 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
153 {
154 	int error;
155 
156 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
157 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
158 	if (error != 0)
159 		return (error);
160 	return (set_fpregs(td, fpregs));
161 }
162 
163 static struct regset *
164 proc_find_regset(struct thread *td, int note)
165 {
166 	struct regset **regsetp, **regset_end, *regset;
167 	struct sysentvec *sv;
168 
169 	sv = td->td_proc->p_sysent;
170 	regsetp = sv->sv_regset_begin;
171 	if (regsetp == NULL)
172 		return (NULL);
173 	regset_end = sv->sv_regset_end;
174 	MPASS(regset_end != NULL);
175 	for (; regsetp < regset_end; regsetp++) {
176 		regset = *regsetp;
177 		if (regset->note != note)
178 			continue;
179 
180 		return (regset);
181 	}
182 
183 	return (NULL);
184 }
185 
186 static int
187 proc_read_regset(struct thread *td, int note, struct iovec *iov)
188 {
189 	struct regset *regset;
190 	struct proc *p;
191 	void *buf;
192 	size_t size;
193 	int error;
194 
195 	regset = proc_find_regset(td, note);
196 	if (regset == NULL)
197 		return (EINVAL);
198 
199 	if (regset->get == NULL)
200 		return (EINVAL);
201 
202 	size = regset->size;
203 	/*
204 	 * The regset is dynamically sized, e.g. the size could change
205 	 * depending on the hardware, or may have a per-thread size.
206 	 */
207 	if (size == 0) {
208 		if (!regset->get(regset, td, NULL, &size))
209 			return (EINVAL);
210 	}
211 
212 	if (iov->iov_base == NULL) {
213 		iov->iov_len = size;
214 		if (iov->iov_len == 0)
215 			return (EINVAL);
216 
217 		return (0);
218 	}
219 
220 	/* The length is wrong, return an error */
221 	if (iov->iov_len != size)
222 		return (EINVAL);
223 
224 	error = 0;
225 	p = td->td_proc;
226 
227 	/* Drop the proc lock while allocating the temp buffer */
228 	PROC_ASSERT_TRACEREQ(p);
229 	PROC_UNLOCK(p);
230 	buf = malloc(size, M_TEMP, M_WAITOK);
231 	PROC_LOCK(p);
232 
233 	if (!regset->get(regset, td, buf, &size)) {
234 		error = EINVAL;
235 	} else {
236 		KASSERT(size == regset->size || regset->size == 0,
237 		    ("%s: Getter function changed the size", __func__));
238 
239 		iov->iov_len = size;
240 		PROC_UNLOCK(p);
241 		error = copyout(buf, iov->iov_base, size);
242 		PROC_LOCK(p);
243 	}
244 
245 	free(buf, M_TEMP);
246 
247 	return (error);
248 }
249 
250 static int
251 proc_write_regset(struct thread *td, int note, struct iovec *iov)
252 {
253 	struct regset *regset;
254 	struct proc *p;
255 	void *buf;
256 	size_t size;
257 	int error;
258 
259 	regset = proc_find_regset(td, note);
260 	if (regset == NULL)
261 		return (EINVAL);
262 
263 	size = regset->size;
264 	/*
265 	 * The regset is dynamically sized, e.g. the size could change
266 	 * depending on the hardware, or may have a per-thread size.
267 	 */
268 	if (size == 0) {
269 		if (!regset->get(regset, td, NULL, &size))
270 			return (EINVAL);
271 	}
272 
273 	/* The length is wrong, return an error */
274 	if (iov->iov_len != size)
275 		return (EINVAL);
276 
277 	if (regset->set == NULL)
278 		return (EINVAL);
279 
280 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
281 	if (error != 0)
282 		return (error);
283 
284 	p = td->td_proc;
285 
286 	/* Drop the proc lock while allocating the temp buffer */
287 	PROC_ASSERT_TRACEREQ(p);
288 	PROC_UNLOCK(p);
289 	buf = malloc(size, M_TEMP, M_WAITOK);
290 	error = copyin(iov->iov_base, buf, size);
291 	PROC_LOCK(p);
292 
293 	if (error == 0) {
294 		if (!regset->set(regset, td, buf, size)) {
295 			error = EINVAL;
296 		}
297 	}
298 
299 	free(buf, M_TEMP);
300 
301 	return (error);
302 }
303 
304 #ifdef COMPAT_FREEBSD32
305 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
306 int
307 proc_read_regs32(struct thread *td, struct reg32 *regs32)
308 {
309 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
310 	return (fill_regs32(td, regs32));
311 }
312 
313 int
314 proc_write_regs32(struct thread *td, struct reg32 *regs32)
315 {
316 	int error;
317 
318 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
319 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
320 	if (error != 0)
321 		return (error);
322 	return (set_regs32(td, regs32));
323 }
324 
325 int
326 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
327 {
328 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
329 	return (fill_dbregs32(td, dbregs32));
330 }
331 
332 int
333 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
334 {
335 	int error;
336 
337 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
338 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
339 	if (error != 0)
340 		return (error);
341 	return (set_dbregs32(td, dbregs32));
342 }
343 
344 int
345 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
346 {
347 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
348 	return (fill_fpregs32(td, fpregs32));
349 }
350 
351 int
352 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
353 {
354 	int error;
355 
356 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
357 	error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
358 	if (error != 0)
359 		return (error);
360 	return (set_fpregs32(td, fpregs32));
361 }
362 #endif
363 
364 int
365 proc_sstep(struct thread *td)
366 {
367 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
368 	return (ptrace_single_step(td));
369 }
370 
371 static int
372 proc_vmspace_check_access(struct thread *td, struct proc *p, int flags)
373 {
374 	PROC_ASSERT_HELD(p);
375 	if ((flags & PRVM_CHECK_DEBUG) != 0)
376 		return (p_candebug(td, p));
377 	if ((flags & PRVM_CHECK_VISIBILITY) != 0)
378 		return (p_cansee(td, p));
379 	return (0);
380 }
381 
382 int
383 proc_vmspace_ref(struct thread *td, struct proc *p, int flags,
384     struct vmspace **vmp)
385 {
386 	struct vmspace *vm;
387 	int error;
388 
389 	MPASS((flags & ~(PRVM_BLOCK_EXEC | PRVM_CHECK_VISIBILITY |
390 	    PRVM_CHECK_DEBUG)) == 0);
391 	MPASS((flags & (PRVM_CHECK_VISIBILITY | PRVM_CHECK_DEBUG)) !=
392 	    (PRVM_CHECK_VISIBILITY | PRVM_CHECK_DEBUG));
393 
394 	PROC_LOCK(p);
395 	if (p != td->td_proc) {
396 		PROC_ASSERT_HELD(p);
397 
398 		/*
399 		 * Make sure that the vmspace doesn't switch out from
400 		 * under us.
401 		 */
402 		if ((flags & PRVM_BLOCK_EXEC) != 0) {
403 			for (;;) {
404 				if (!execve_block(td, p)) {
405 					PROC_LOCK(p);
406 					continue;
407 				}
408 				error = proc_vmspace_check_access(td, p, flags);
409 				if (error != 0) {
410 					execve_unblock(td, p);
411 					PROC_UNLOCK(p);
412 					return (error);
413 				}
414 				break;
415 			}
416 		} else {
417 			error = proc_vmspace_check_access(td, p, flags);
418 			if (error != 0) {
419 				PROC_UNLOCK(p);
420 				return (error);
421 			}
422 		}
423 	}
424 	vm = vmspace_acquire_ref(p);
425 	if (vm == NULL) {
426 		if (p != td->td_proc && (flags & PRVM_BLOCK_EXEC) != 0)
427 			execve_unblock(td, p);
428 		PROC_UNLOCK(p);
429 		return (ESRCH);
430 	}
431 	PROC_UNLOCK(p);
432 	*vmp = vm;
433 	return (0);
434 }
435 
436 void
437 proc_vmspace_unref(struct thread *td, struct proc *p, int flags,
438     struct vmspace *vm)
439 {
440 	vmspace_free(vm);
441 	if (p != td->td_proc && (flags & PRVM_BLOCK_EXEC) != 0) {
442 		PROC_LOCK(p);
443 		PROC_ASSERT_HELD(p);
444 		execve_unblock(td, p);
445 		PROC_UNLOCK(p);
446 	}
447 }
448 
449 static int
450 vmspace_rwmem(struct vmspace *vm, struct uio *uio)
451 {
452 	vm_map_t map;
453 	vm_offset_t pageno;		/* page number */
454 	vm_prot_t reqprot;
455 	ssize_t orig_resid;
456 	int error, fault_flags, page_offset, writing;
457 
458 	map = &vm->vm_map;
459 
460 	/*
461 	 * If we are writing, then we request vm_fault() to create a private
462 	 * copy of each page.  Since these copies will not be writeable by the
463 	 * process, we must explicitly request that they be dirtied.
464 	 */
465 	writing = uio->uio_rw == UIO_WRITE;
466 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
467 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
468 
469 	orig_resid = uio->uio_resid;
470 
471 	if (writing) {
472 		error = priv_check(curthread, PRIV_PROC_MEM_WRITE);
473 		if (error != 0)
474 			return (error);
475 	}
476 
477 	/*
478 	 * Only map in one page at a time.  We don't have to, but it
479 	 * makes things easier.  This way is trivial - right?
480 	 */
481 	do {
482 		vm_offset_t uva;
483 		u_int len;
484 		vm_page_t m;
485 
486 		uva = (vm_offset_t)uio->uio_offset;
487 
488 		/*
489 		 * Get the page number of this segment.
490 		 */
491 		pageno = trunc_page(uva);
492 		page_offset = uva - pageno;
493 
494 		/*
495 		 * How many bytes to copy
496 		 */
497 		len = MIN(PAGE_SIZE - page_offset, uio->uio_resid);
498 
499 		/*
500 		 * Fault and hold the page on behalf of the process.
501 		 */
502 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
503 		if (error != KERN_SUCCESS) {
504 			if (error == KERN_RESOURCE_SHORTAGE)
505 				error = ENOMEM;
506 			else
507 				error = EFAULT;
508 			break;
509 		}
510 
511 		/*
512 		 * Now do the i/o move.
513 		 */
514 		error = uiomove_fromphys(&m, page_offset, len, uio);
515 
516 		/* Make the I-cache coherent for breakpoints. */
517 		if (writing && error == 0) {
518 			vm_map_lock_read(map);
519 			if (vm_map_check_protection(map, pageno, pageno +
520 			    PAGE_SIZE, VM_PROT_EXECUTE))
521 				vm_sync_icache(map, uva, len);
522 			vm_map_unlock_read(map);
523 		}
524 
525 		/*
526 		 * Release the page.
527 		 */
528 		vm_page_unwire(m, PQ_ACTIVE);
529 
530 	} while (error == 0 && uio->uio_resid > 0);
531 	return (uio->uio_resid == orig_resid ? error : 0);
532 }
533 
534 int
535 proc_rwmem(struct proc *p, struct uio *uio, int flags)
536 {
537 	struct vmspace *vm;
538 	struct thread *td;
539 	int error;
540 
541 	td = curthread;
542 	error = proc_vmspace_ref(td, p, flags, &vm);
543 	if (error != 0)
544 		return (error);
545 	error = vmspace_rwmem(vm, uio);
546 	proc_vmspace_unref(td, p, flags, vm);
547 	return (error);
548 }
549 
550 ssize_t
551 vmspace_iop(struct thread *td, struct vmspace *vm, vm_offset_t va, void *buf,
552     size_t len, enum uio_rw rw)
553 {
554 	struct iovec iov;
555 	struct uio uio;
556 	ssize_t slen;
557 	int error;
558 
559 	MPASS(len < SSIZE_MAX);
560 	slen = (ssize_t)len;
561 
562 	iov.iov_base = (caddr_t)buf;
563 	iov.iov_len = len;
564 	uio.uio_iov = &iov;
565 	uio.uio_iovcnt = 1;
566 	uio.uio_offset = va;
567 	uio.uio_resid = slen;
568 	uio.uio_segflg = UIO_SYSSPACE;
569 	uio.uio_rw = rw;
570 	uio.uio_td = td;
571 	error = vmspace_rwmem(vm, &uio);
572 	if (error != 0 || uio.uio_resid == slen)
573 		return (-1);
574 	return (slen - uio.uio_resid);
575 }
576 
577 ssize_t
578 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
579     size_t len)
580 {
581 
582 	return (vmspace_iop(td, p->p_vmspace, va, buf, len, UIO_READ));
583 }
584 
585 ssize_t
586 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
587     size_t len)
588 {
589 
590 	return (vmspace_iop(td, p->p_vmspace, va, buf, len, UIO_WRITE));
591 }
592 
593 static int
594 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
595 {
596 	struct vattr vattr;
597 	vm_map_t map;
598 	vm_map_entry_t entry;
599 	vm_object_t obj, tobj, lobj;
600 	struct vmspace *vm;
601 	struct vnode *vp;
602 	char *freepath, *fullpath;
603 	u_int pathlen;
604 	int error, index;
605 
606 	error = 0;
607 	obj = NULL;
608 
609 	vm = vmspace_acquire_ref(p);
610 	map = &vm->vm_map;
611 	vm_map_lock_read(map);
612 
613 	do {
614 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
615 		    ("Submap in map header"));
616 		index = 0;
617 		VM_MAP_ENTRY_FOREACH(entry, map) {
618 			if (index >= pve->pve_entry &&
619 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
620 				break;
621 			index++;
622 		}
623 		if (index < pve->pve_entry) {
624 			error = EINVAL;
625 			break;
626 		}
627 		if (entry == &map->header) {
628 			error = ENOENT;
629 			break;
630 		}
631 
632 		/* We got an entry. */
633 		pve->pve_entry = index + 1;
634 		pve->pve_timestamp = map->timestamp;
635 		pve->pve_start = entry->start;
636 		pve->pve_end = entry->end - 1;
637 		pve->pve_offset = entry->offset;
638 		pve->pve_prot = entry->protection |
639 		    PROT_MAX(entry->max_protection);
640 
641 		/* Backing object's path needed? */
642 		if (pve->pve_pathlen == 0)
643 			break;
644 
645 		pathlen = pve->pve_pathlen;
646 		pve->pve_pathlen = 0;
647 
648 		obj = entry->object.vm_object;
649 		if (obj != NULL)
650 			VM_OBJECT_RLOCK(obj);
651 	} while (0);
652 
653 	vm_map_unlock_read(map);
654 
655 	pve->pve_fsid = VNOVAL;
656 	pve->pve_fileid = VNOVAL;
657 
658 	if (error == 0 && obj != NULL) {
659 		lobj = obj;
660 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
661 			if (tobj != obj)
662 				VM_OBJECT_RLOCK(tobj);
663 			if (lobj != obj)
664 				VM_OBJECT_RUNLOCK(lobj);
665 			lobj = tobj;
666 			pve->pve_offset += tobj->backing_object_offset;
667 		}
668 		vp = vm_object_vnode(lobj);
669 		if (vp != NULL)
670 			vref(vp);
671 		if (lobj != obj)
672 			VM_OBJECT_RUNLOCK(lobj);
673 		VM_OBJECT_RUNLOCK(obj);
674 
675 		if (vp != NULL) {
676 			freepath = NULL;
677 			fullpath = NULL;
678 			vn_fullpath(vp, &fullpath, &freepath);
679 			vn_lock(vp, LK_SHARED | LK_RETRY);
680 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
681 				pve->pve_fileid = vattr.va_fileid;
682 				pve->pve_fsid = vattr.va_fsid;
683 			}
684 			vput(vp);
685 
686 			if (fullpath != NULL) {
687 				pve->pve_pathlen = strlen(fullpath) + 1;
688 				if (pve->pve_pathlen <= pathlen) {
689 					error = copyout(fullpath, pve->pve_path,
690 					    pve->pve_pathlen);
691 				} else
692 					error = ENAMETOOLONG;
693 			}
694 			if (freepath != NULL)
695 				free(freepath, M_TEMP);
696 		}
697 	}
698 	vmspace_free(vm);
699 	if (error == 0)
700 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
701 		    p->p_pid, pve->pve_entry, pve->pve_start);
702 
703 	return (error);
704 }
705 
706 /*
707  * Process debugging system call.
708  */
709 #ifndef _SYS_SYSPROTO_H_
710 struct ptrace_args {
711 	int	req;
712 	pid_t	pid;
713 	caddr_t	addr;
714 	int	data;
715 };
716 #endif
717 
718 static int
719 ptrace_useraction(struct thread *td, int req, bool pd_mode, pid_t pid, int pfd,
720     lwpid_t lwpid, void *uaddr, int udata)
721 {
722 	/*
723 	 * XXX this obfuscation is to reduce stack usage, but the register
724 	 * structs may be too large to put on the stack anyway.
725 	 */
726 	union {
727 		struct ptrace_io_desc piod;
728 		struct ptrace_lwpinfo pl;
729 		struct ptrace_vm_entry pve;
730 		struct ptrace_coredump pc;
731 		struct ptrace_sc_remote sr;
732 		struct dbreg dbreg;
733 		struct fpreg fpreg;
734 		struct reg reg;
735 		struct iovec vec;
736 		syscallarg_t args[nitems(td->td_sa.args)];
737 		struct ptrace_sc_ret psr;
738 		int ptevents;
739 		struct ptrace_child *children;
740 		char sv_name[32];
741 	} r;
742 	syscallarg_t pscr_args[nitems(td->td_sa.args)];
743 	void *addr;
744 	int error, data;
745 
746 	if (!allow_ptrace)
747 		return (ENOSYS);
748 
749 	error = 0;
750 	addr = &r;
751 
752 	switch (req) {
753 	case PT_GET_EVENT_MASK:
754 	case PT_LWPINFO:
755 	case PT_GET_SC_ARGS:
756 	case PT_GET_SC_RET:
757 		break;
758 	case PT_SET_SC_RET:
759 		error = udata != sizeof(r.psr) ? EINVAL :
760 		    copyin(uaddr, &r.psr, sizeof(r.psr));
761 		break;
762 	case PT_GETREGS:
763 		bzero(&r.reg, sizeof(r.reg));
764 		break;
765 	case PT_GETFPREGS:
766 		bzero(&r.fpreg, sizeof(r.fpreg));
767 		break;
768 	case PT_GETDBREGS:
769 		bzero(&r.dbreg, sizeof(r.dbreg));
770 		break;
771 	case PT_GETREGSET:
772 	case PT_SETREGSET:
773 		error = copyin(uaddr, &r.vec, sizeof(r.vec));
774 		break;
775 	case PT_SETREGS:
776 		error = copyin(uaddr, &r.reg, sizeof(r.reg));
777 		break;
778 	case PT_SETFPREGS:
779 		error = copyin(uaddr, &r.fpreg, sizeof(r.fpreg));
780 		break;
781 	case PT_SETDBREGS:
782 		error = copyin(uaddr, &r.dbreg, sizeof(r.dbreg));
783 		break;
784 	case PT_SET_EVENT_MASK:
785 		error = udata != sizeof(r.ptevents) ? EINVAL :
786 		    copyin(uaddr, &r.ptevents, udata);
787 		break;
788 	case PT_IO:
789 		error = copyin(uaddr, &r.piod, sizeof(r.piod));
790 		break;
791 	case PT_VM_ENTRY:
792 		error = copyin(uaddr, &r.pve, sizeof(r.pve));
793 		break;
794 	case PT_COREDUMP:
795 		error = udata != sizeof(r.pc) ? EINVAL :
796 		    copyin(uaddr, &r.pc, udata);
797 		break;
798 	case PT_SC_REMOTE:
799 		error = udata != sizeof(r.sr) ? EINVAL :
800 		    copyin(uaddr, &r.sr, udata);
801 		if (error != 0)
802 			break;
803 		if (r.sr.pscr_nargs > nitems(td->td_sa.args)) {
804 			error = EINVAL;
805 			break;
806 		}
807 		error = copyin(r.sr.pscr_args, pscr_args,
808 		    sizeof(u_long) * r.sr.pscr_nargs);
809 		if (error != 0)
810 			break;
811 		r.sr.pscr_args = pscr_args;
812 		break;
813 	case PT_GET_CHILDREN:
814 		if (uaddr == NULL)
815 			addr = NULL;
816 		else if (udata < 0)
817 			error = EINVAL;
818 		else
819 			addr = &r.children;
820 		break;
821 	case PT_GET_ABI_NAME:
822 		if (udata < 0) {
823 			error = EINVAL;
824 			break;
825 		}
826 		data = udata;
827 		udata = sizeof(r.sv_name);
828 		break;
829 	case PTINTERNAL_FIRST ... PTINTERNAL_LAST:
830 		error = EINVAL;
831 		break;
832 	default:
833 		addr = uaddr;
834 		break;
835 	}
836 	if (error != 0)
837 		return (error);
838 
839 	error = ptrace_action(td, req, pd_mode, pid, pfd, lwpid, addr, udata);
840 	if (error != 0)
841 		return (error);
842 
843 	switch (req) {
844 	case PT_VM_ENTRY:
845 		error = copyout(&r.pve, uaddr, sizeof(r.pve));
846 		break;
847 	case PT_IO:
848 		error = copyout(&r.piod, uaddr, sizeof(r.piod));
849 		break;
850 	case PT_GETREGS:
851 		error = copyout(&r.reg, uaddr, sizeof(r.reg));
852 		break;
853 	case PT_GETFPREGS:
854 		error = copyout(&r.fpreg, uaddr, sizeof(r.fpreg));
855 		break;
856 	case PT_GETDBREGS:
857 		error = copyout(&r.dbreg, uaddr, sizeof(r.dbreg));
858 		break;
859 	case PT_GETREGSET:
860 		error = copyout(&r.vec, uaddr, sizeof(r.vec));
861 		break;
862 	case PT_GET_EVENT_MASK:
863 		/* NB: The size in uap->data is validated in ptraceimpl(). */
864 		error = copyout(&r.ptevents, uaddr, udata);
865 		break;
866 	case PT_LWPINFO:
867 		/* NB: The size in uap->data is validated in ptraceimpl(). */
868 		error = copyout(&r.pl, uaddr, udata);
869 		break;
870 	case PT_GET_SC_ARGS:
871 		error = copyout(r.args, uaddr, MIN(udata, sizeof(r.args)));
872 		break;
873 	case PT_GET_SC_RET:
874 		error = copyout(&r.psr, uaddr, MIN(udata, sizeof(r.psr)));
875 		break;
876 	case PT_SC_REMOTE:
877 		error = copyout(&r.sr.pscr_ret, (char *)uaddr +
878 		    offsetof(struct ptrace_sc_remote, pscr_ret),
879 		    sizeof(r.sr.pscr_ret));
880 		break;
881 	case PT_GET_CHILDREN:
882 		if (uaddr != NULL) {
883 			error = copyout(r.children, uaddr,
884 			    td->td_retval[0] * sizeof(struct ptrace_child));
885 			free(r.children, M_TEMP);
886 		}
887 		break;
888 	case PT_GET_ABI_NAME:
889 		error = data <= strlen(r.sv_name) ? ENOMEM :
890 		    copyout(&r.sv_name, uaddr, strlen(r.sv_name) + 1);
891 		break;
892 	}
893 
894 	return (error);
895 }
896 
897 #ifdef COMPAT_FREEBSD32
898 /*
899  *   PROC_READ(regs, td2, addr);
900  * becomes either:
901  *   proc_read_regs(td2, addr);
902  * or
903  *   proc_read_regs32(td2, addr);
904  * .. except this is done at runtime.  There is an additional
905  * complication in that PROC_WRITE disallows 32 bit consumers
906  * from writing to 64 bit address space targets.
907  */
908 #define	PROC_READ(w, t, a)	wrap32 ? \
909 	proc_read_ ## w ## 32(t, a) : \
910 	proc_read_ ## w (t, a)
911 #define	PROC_WRITE(w, t, a)	wrap32 ? \
912 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
913 	proc_write_ ## w (t, a)
914 #else
915 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
916 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
917 #endif
918 
919 void
920 proc_set_traced(struct proc *p, bool stop)
921 {
922 
923 	sx_assert(&proctree_lock, SX_XLOCKED);
924 	PROC_LOCK_ASSERT(p, MA_OWNED);
925 	p->p_flag |= P_TRACED;
926 	if (stop)
927 		p->p_flag2 |= P2_PTRACE_FSTP;
928 	p->p_ptevents = PTRACE_DEFAULT;
929 }
930 
931 void
932 ptrace_unsuspend(struct proc *p)
933 {
934 	PROC_LOCK_ASSERT(p, MA_OWNED);
935 
936 	PROC_SLOCK(p);
937 	p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
938 	thread_unsuspend(p);
939 	PROC_SUNLOCK(p);
940 	itimer_proc_continue(p);
941 	kqtimer_proc_continue(p);
942 }
943 
944 static int
945 proc_can_ptrace1(struct thread *td, struct proc *p)
946 {
947 	int error;
948 
949 	PROC_LOCK_ASSERT(p, MA_OWNED);
950 
951 	if ((p->p_flag & P_WEXIT) != 0)
952 		return (ESRCH);
953 	if ((error = p_cansee(td, p)) != 0)
954 		return (error);
955 	if ((error = p_candebug(td, p)) != 0)
956 		return (error);
957 	return (0);
958 }
959 
960 static int
961 proc_can_ptrace(struct thread *td, struct proc *p)
962 {
963 	int error;
964 
965 	PROC_LOCK_ASSERT(p, MA_OWNED);
966 
967 	if ((error = proc_can_ptrace1(td, p)) != 0)
968 		return (error);
969 
970 	/* not being traced... */
971 	if ((p->p_flag & P_TRACED) == 0)
972 		return (EPERM);
973 
974 	/* not being traced by YOU */
975 	if (p->p_pptr != td->td_proc)
976 		return (EBUSY);
977 
978 	/* not currently stopped */
979 	if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
980 	    p->p_suspcount != p->p_numthreads  ||
981 	    (p->p_flag & P_WAITED) == 0)
982 		return (EBUSY);
983 
984 	return (0);
985 }
986 
987 static int
988 ptrace_count_children(struct thread *td, struct proc *p, bool count_everything)
989 {
990 	struct proc *pp;
991 	int error, num;
992 
993 	sx_assert(&proctree_lock, SX_LOCKED);
994 	num = 0;
995 	LIST_FOREACH(pp, &p->p_children, p_sibling) {
996 		if (count_everything) {
997 			error = 0;
998 		} else {
999 			PROC_LOCK(pp);
1000 			error = p_cansee(td, pp);
1001 			PROC_UNLOCK(pp);
1002 		}
1003 		if (error != 0)
1004 			continue;
1005 		num++;
1006 	}
1007 	LIST_FOREACH(pp, &p->p_orphans, p_orphan) {
1008 		if (count_everything) {
1009 			error = 0;
1010 		} else {
1011 			PROC_LOCK(pp);
1012 			error = p_cansee(td, pp);
1013 			PROC_UNLOCK(pp);
1014 		}
1015 		if (error != 0)
1016 			continue;
1017 		num++;
1018 	}
1019 	return (num);
1020 }
1021 
1022 static bool
1023 ptrace_report_child(struct thread *td, struct proc *p, struct proc *pp,
1024     struct ptrace_child *ptc)
1025 {
1026 	sx_assert(&proctree_lock, SX_LOCKED);
1027 
1028 	PROC_LOCK(pp);
1029 	if (p_cansee(td, pp) != 0) {
1030 		PROC_UNLOCK(pp);
1031 		return (false);
1032 	}
1033 	ptc->pid = pp->p_pid;
1034 	if ((pp->p_flag & P_TRACED) != 0) {
1035 		ptc->flags |= PTCHLD_TRACED;
1036 		if (pp->p_pptr == td->td_proc)
1037 			ptc->flags |= PTCHLD_TRACED_BY_ME;
1038 	}
1039 	if ((pp->p_flag & P_WEXIT) != 0)
1040 		ptc->flags |= PTCHLD_EXITED;
1041 	PROC_UNLOCK(pp);
1042 	return (true);
1043 }
1044 
1045 static struct thread *
1046 ptrace_sel_coredump_thread(struct proc *p)
1047 {
1048 	struct thread *td2;
1049 
1050 	PROC_LOCK_ASSERT(p, MA_OWNED);
1051 	MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
1052 
1053 	FOREACH_THREAD_IN_PROC(p, td2) {
1054 		if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
1055 			return (td2);
1056 	}
1057 	return (NULL);
1058 }
1059 
1060 int
1061 ptrace_action(struct thread *td, int req, bool pd_mode, pid_t pid, int pfd,
1062     lwpid_t lwpid, void *addr, int data)
1063 {
1064 	struct iovec iov;
1065 	struct uio uio;
1066 	struct proc *curp, *p, *pp;
1067 	struct thread *td2 = NULL, *td3;
1068 	struct ptrace_io_desc *piod = NULL;
1069 	struct ptrace_lwpinfo *pl;
1070 	struct ptrace_sc_ret *psr;
1071 	struct ptrace_sc_remote *pscr;
1072 	struct file *fp;
1073 	struct ptrace_coredump *pc;
1074 	struct thr_coredump_req *tcq;
1075 	struct thr_syscall_req *tsr;
1076 	struct file *pfp;
1077 	struct ptrace_child *children, *ptc;
1078 	int error, num, num1, tmp;
1079 	lwpid_t tid = 0, *buf;
1080 #ifdef COMPAT_FREEBSD32
1081 	int wrap32 = 0, safe = 0;
1082 #endif
1083 	bool need_can_ptrace, proctree_locked, p2_req_set;
1084 
1085 	curp = td->td_proc;
1086 	proctree_locked = false;
1087 	p2_req_set = false;
1088 	pfp = NULL;
1089 
1090 	/* Lock proctree before locking the process. */
1091 	switch (req) {
1092 	case PT_TRACE_ME:
1093 	case PT_ATTACH:
1094 	case PT_STEP:
1095 	case PT_CONTINUE:
1096 	case PT_TO_SCE:
1097 	case PT_TO_SCX:
1098 	case PT_SYSCALL:
1099 	case PT_FOLLOW_FORK:
1100 	case PT_LWP_EVENTS:
1101 	case PT_GET_EVENT_MASK:
1102 	case PT_SET_EVENT_MASK:
1103 	case PT_DETACH:
1104 	case PT_GET_SC_ARGS:
1105 	case PT_GET_CHILDREN:
1106 		sx_xlock(&proctree_lock);
1107 		proctree_locked = true;
1108 		break;
1109 	default:
1110 		break;
1111 	}
1112 
1113 	if (req == PT_TRACE_ME) {
1114 		p = td->td_proc;
1115 		PROC_LOCK(p);
1116 	} else if (pd_mode) {
1117 		if (!proctree_locked)
1118 			sx_slock(&proctree_lock);
1119 		error = fget_procdesc(td, pfd, &cap_ptrace_rights, EINVAL,
1120 		    &pfp, NULL, &p);
1121 		if (!proctree_locked)
1122 			sx_sunlock(&proctree_lock);
1123 		if (error != 0)
1124 			goto fail_proctree;
1125 		pid = p->p_pid;
1126 		if (lwpid != -1) {
1127 			FOREACH_THREAD_IN_PROC(p, td2) {
1128 				if (td2->td_tid == lwpid)
1129 					break;
1130 			}
1131 			if (td2 == NULL) {
1132 				PROC_UNLOCK(p);
1133 				error = ESRCH;
1134 				goto fail_proctree;
1135 			}
1136 			tid = td2->td_tid;
1137 		}
1138 	} else if (pid <= PID_MAX) {
1139 		if ((p = pfind(pid)) == NULL) {
1140 			error = ESRCH;
1141 			goto fail_proctree;
1142 		}
1143 	} else {
1144 		td2 = tdfind(pid, -1);
1145 		if (td2 == NULL) {
1146 			error = ESRCH;
1147 			goto fail_proctree;
1148 		}
1149 		p = td2->td_proc;
1150 		tid = pid;
1151 		pid = p->p_pid;
1152 	}
1153 	AUDIT_ARG_PROCESS(p);
1154 
1155 	error = proc_can_ptrace1(td, p);
1156 	if (error != 0)
1157 		goto fail;
1158 
1159 	/*
1160 	 * System processes can't be debugged.
1161 	 */
1162 	if ((p->p_flag & P_SYSTEM) != 0) {
1163 		error = EINVAL;
1164 		goto fail;
1165 	}
1166 
1167 	if (tid == 0) {
1168 		if ((p->p_flag & P_STOPPED_TRACE) != 0)
1169 			td2 = p->p_xthread;
1170 		if (td2 == NULL)
1171 			td2 = FIRST_THREAD_IN_PROC(p);
1172 		tid = td2->td_tid;
1173 	}
1174 
1175 #ifdef COMPAT_FREEBSD32
1176 	/*
1177 	 * Test if we're a 32 bit client and what the target is.
1178 	 * Set the wrap controls accordingly.
1179 	 */
1180 	if (SV_CURPROC_FLAG(SV_ILP32)) {
1181 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
1182 			safe = 1;
1183 		wrap32 = 1;
1184 	}
1185 #endif
1186 	/*
1187 	 * Permissions check
1188 	 */
1189 	need_can_ptrace = true;
1190 	switch (req) {
1191 	case PT_TRACE_ME:
1192 		/*
1193 		 * Always legal, when there is a parent process which
1194 		 * could trace us.  Otherwise, reject.
1195 		 */
1196 		if ((p->p_flag & P_TRACED) != 0) {
1197 			error = EBUSY;
1198 			goto fail;
1199 		}
1200 		if (p->p_pptr == initproc) {
1201 			error = EPERM;
1202 			goto fail;
1203 		}
1204 		break;
1205 
1206 	case PT_ATTACH:
1207 		/* Self */
1208 		if (p == td->td_proc) {
1209 			error = EINVAL;
1210 			goto fail;
1211 		}
1212 
1213 		/* Already traced */
1214 		if (p->p_flag & P_TRACED) {
1215 			error = EBUSY;
1216 			goto fail;
1217 		}
1218 
1219 		/* Can't trace an ancestor if you're being traced. */
1220 		if (curp->p_flag & P_TRACED) {
1221 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
1222 				if (pp == p) {
1223 					error = EINVAL;
1224 					goto fail;
1225 				}
1226 			}
1227 		}
1228 
1229 		/* OK */
1230 		break;
1231 
1232 	default:
1233 		/*
1234 		 * Allow thread to clear single step for itself.
1235 		 * PT_GET_CHILDREN on itself does not need P_TRACED.
1236 		 */
1237 		if ((req == PT_CLEARSTEP && td->td_tid == tid) ||
1238 		    (req == PT_GET_CHILDREN && p == curp))
1239 			need_can_ptrace = false;
1240 
1241 		/*
1242 		 * Check for ptrace eligibility before waiting for
1243 		 * holds to drain.
1244 		 */
1245 		if (need_can_ptrace) {
1246 			error = proc_can_ptrace(td, p);
1247 			if (error != 0)
1248 				goto fail;
1249 		}
1250 
1251 		/*
1252 		 * Block parallel ptrace requests.  Most important, do
1253 		 * not allow other thread in debugger to continue the
1254 		 * debuggee until coredump finished.
1255 		 */
1256 		while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
1257 			if (proctree_locked)
1258 				sx_xunlock(&proctree_lock);
1259 			error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
1260 			    (proctree_locked ? PDROP : 0), "pptrace", 0);
1261 			if (proctree_locked) {
1262 				sx_xlock(&proctree_lock);
1263 				PROC_LOCK(p);
1264 			}
1265 			if (error == 0 && td2->td_proc != p)
1266 				error = ESRCH;
1267 			if (error == 0 && need_can_ptrace)
1268 				error = proc_can_ptrace(td, p);
1269 			if (error != 0)
1270 				goto fail;
1271 		}
1272 
1273 		/* Ok */
1274 		break;
1275 	}
1276 
1277 	/*
1278 	 * Keep this process around and request parallel ptrace()
1279 	 * request to wait until we finish this request.
1280 	 */
1281 	MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
1282 	p->p_flag2 |= P2_PTRACEREQ;
1283 	p2_req_set = true;
1284 	_PHOLD(p);
1285 
1286 	/*
1287 	 * Actually do the requests
1288 	 */
1289 
1290 	td->td_retval[0] = 0;
1291 
1292 	switch (req) {
1293 	case PT_TRACE_ME:
1294 		/* set my trace flag and "owner" so it can read/write me */
1295 		proc_set_traced(p, false);
1296 		if (p->p_flag & P_PPWAIT)
1297 			p->p_flag |= P_PPTRACE;
1298 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
1299 		break;
1300 
1301 	case PT_ATTACH:
1302 		/* security check done above */
1303 		/*
1304 		 * It would be nice if the tracing relationship was separate
1305 		 * from the parent relationship but that would require
1306 		 * another set of links in the proc struct or for "wait"
1307 		 * to scan the entire proc table.  To make life easier,
1308 		 * we just re-parent the process we're trying to trace.
1309 		 * The old parent is remembered so we can put things back
1310 		 * on a "detach".
1311 		 */
1312 		proc_set_traced(p, true);
1313 		proc_reparent(p, td->td_proc, false);
1314 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
1315 		    p->p_oppid);
1316 
1317 		sx_xunlock(&proctree_lock);
1318 		proctree_locked = false;
1319 		MPASS(p->p_xthread == NULL);
1320 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
1321 
1322 		/*
1323 		 * If already stopped due to a stop signal, clear the
1324 		 * existing stop before triggering a traced SIGSTOP.
1325 		 */
1326 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
1327 			PROC_SLOCK(p);
1328 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
1329 			thread_unsuspend(p);
1330 			PROC_SUNLOCK(p);
1331 		}
1332 
1333 		kern_psignal(p, SIGSTOP);
1334 		break;
1335 
1336 	case PT_CLEARSTEP:
1337 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
1338 		    p->p_pid);
1339 		error = ptrace_clear_single_step(td2);
1340 		break;
1341 
1342 	case PT_SETSTEP:
1343 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
1344 		    p->p_pid);
1345 		error = ptrace_single_step(td2);
1346 		break;
1347 
1348 	case PT_SUSPEND:
1349 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
1350 		    p->p_pid);
1351 		td2->td_dbgflags |= TDB_SUSPEND;
1352 		ast_sched(td2, TDA_SUSPEND);
1353 		break;
1354 
1355 	case PT_RESUME:
1356 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
1357 		    p->p_pid);
1358 		td2->td_dbgflags &= ~TDB_SUSPEND;
1359 		break;
1360 
1361 	case PT_FOLLOW_FORK:
1362 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
1363 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
1364 		    data ? "enabled" : "disabled");
1365 		if (data)
1366 			p->p_ptevents |= PTRACE_FORK;
1367 		else
1368 			p->p_ptevents &= ~PTRACE_FORK;
1369 		break;
1370 
1371 	case PT_LWP_EVENTS:
1372 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
1373 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
1374 		    data ? "enabled" : "disabled");
1375 		if (data)
1376 			p->p_ptevents |= PTRACE_LWP;
1377 		else
1378 			p->p_ptevents &= ~PTRACE_LWP;
1379 		break;
1380 
1381 	case PT_GET_EVENT_MASK:
1382 		if (data != sizeof(p->p_ptevents)) {
1383 			error = EINVAL;
1384 			break;
1385 		}
1386 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1387 		    p->p_ptevents);
1388 		*(int *)addr = p->p_ptevents;
1389 		break;
1390 
1391 	case PT_SET_EVENT_MASK:
1392 		if (data != sizeof(p->p_ptevents)) {
1393 			error = EINVAL;
1394 			break;
1395 		}
1396 		tmp = *(int *)addr;
1397 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1398 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1399 			error = EINVAL;
1400 			break;
1401 		}
1402 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1403 		    p->p_pid, p->p_ptevents, tmp);
1404 		p->p_ptevents = tmp;
1405 		break;
1406 
1407 	case PT_GET_SC_ARGS:
1408 	case PTLINUX_GET_SC_ARGS:
1409 		CTR2(KTR_PTRACE, "%s: pid %d", req == PT_GET_SC_ARGS ?
1410 		    "PT_GET_SC_ARGS" : "PT_LINUX_GET_SC_ARGS", p->p_pid);
1411 		if (((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0 &&
1412 		     td2->td_sa.code == 0)
1413 #ifdef COMPAT_FREEBSD32
1414 		    || (wrap32 && !safe)
1415 #endif
1416 		    ) {
1417 			error = EINVAL;
1418 			break;
1419 		}
1420 		if (req == PT_GET_SC_ARGS) {
1421 			bzero(addr, sizeof(td2->td_sa.args));
1422 			bcopy(td2->td_sa.args, addr, td2->td_sa.callp->sy_narg *
1423 			    sizeof(syscallarg_t));
1424 		} else {
1425 			/*
1426 			 * Emulate a Linux bug which which strace(1) depends on:
1427 			 * at initialization it tests whether ptrace works by
1428 			 * calling close(2), or some other single-argument
1429 			 * syscall, _with six arguments_, and then verifies
1430 			 * whether it can fetch them all using this API;
1431 			 * otherwise it bails out.
1432 			 */
1433 			bcopy(td2->td_sa.args, addr, 6 * sizeof(syscallarg_t));
1434 		}
1435 		break;
1436 
1437 	case PT_GET_SC_RET:
1438 		if ((td2->td_dbgflags & TDB_SCX) == 0
1439 #ifdef COMPAT_FREEBSD32
1440 		    || (wrap32 && !safe)
1441 #endif
1442 		    ) {
1443 			error = EINVAL;
1444 			break;
1445 		}
1446 		psr = addr;
1447 		bzero(psr, sizeof(*psr));
1448 		psr->sr_error = td2->td_errno;
1449 		if (psr->sr_error == 0) {
1450 			psr->sr_retval[0] = td2->td_retval[0];
1451 			psr->sr_retval[1] = td2->td_retval[1];
1452 		}
1453 		CTR4(KTR_PTRACE,
1454 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1455 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1456 		    psr->sr_retval[1]);
1457 		break;
1458 
1459 	case PT_SET_SC_RET:
1460 		if ((td2->td_dbgflags & TDB_SCE) == 0
1461 #ifdef COMPAT_FREEBSD32
1462 		    || (wrap32 && !safe)
1463 #endif
1464 		    ) {
1465 			error = EINVAL;
1466 			break;
1467 		}
1468 		psr = addr;
1469 		td2->td_errno = psr->sr_error;
1470 		if (td2->td_errno == 0) {
1471 			td2->td_retval[0] = psr->sr_retval[0];
1472 			td2->td_retval[1] = psr->sr_retval[1];
1473 		}
1474 		td2->td_dbgflags |= TDB_SET_SC_RET;
1475 		break;
1476 
1477 	case PT_STEP:
1478 	case PT_CONTINUE:
1479 	case PT_TO_SCE:
1480 	case PT_TO_SCX:
1481 	case PT_SYSCALL:
1482 	case PT_DETACH:
1483 		/* Zero means do not send any signal */
1484 		if (data < 0 || data > _SIG_MAXSIG) {
1485 			error = EINVAL;
1486 			break;
1487 		}
1488 
1489 		switch (req) {
1490 		case PT_STEP:
1491 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1492 			    td2->td_tid, p->p_pid, data);
1493 			error = ptrace_single_step(td2);
1494 			if (error != 0)
1495 				goto out;
1496 			break;
1497 		case PT_CONTINUE:
1498 		case PT_TO_SCE:
1499 		case PT_TO_SCX:
1500 		case PT_SYSCALL:
1501 			if (addr != (void *)1) {
1502 				error = ptrace_set_pc(td2,
1503 				    (u_long)(uintfptr_t)addr);
1504 				if (error != 0)
1505 					goto out;
1506 				td2->td_dbgflags |= TDB_USERWR;
1507 			}
1508 			switch (req) {
1509 			case PT_TO_SCE:
1510 				p->p_ptevents |= PTRACE_SCE;
1511 				CTR4(KTR_PTRACE,
1512 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1513 				    p->p_pid, p->p_ptevents,
1514 				    (u_long)(uintfptr_t)addr, data);
1515 				break;
1516 			case PT_TO_SCX:
1517 				p->p_ptevents |= PTRACE_SCX;
1518 				CTR4(KTR_PTRACE,
1519 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1520 				    p->p_pid, p->p_ptevents,
1521 				    (u_long)(uintfptr_t)addr, data);
1522 				break;
1523 			case PT_SYSCALL:
1524 				p->p_ptevents |= PTRACE_SYSCALL;
1525 				CTR4(KTR_PTRACE,
1526 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1527 				    p->p_pid, p->p_ptevents,
1528 				    (u_long)(uintfptr_t)addr, data);
1529 				break;
1530 			case PT_CONTINUE:
1531 				CTR3(KTR_PTRACE,
1532 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1533 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1534 				break;
1535 			}
1536 			break;
1537 		case PT_DETACH:
1538 			/*
1539 			 * Clear P_TRACED before reparenting
1540 			 * a detached process back to its original
1541 			 * parent.  Otherwise the debugee will be set
1542 			 * as an orphan of the debugger.
1543 			 */
1544 			p->p_flag &= ~(P_TRACED | P_WAITED);
1545 
1546 			/*
1547 			 * Reset the process parent.
1548 			 */
1549 			if (p->p_oppid != p->p_pptr->p_pid) {
1550 				PROC_LOCK(p->p_pptr);
1551 				sigqueue_take(p->p_ksi);
1552 				PROC_UNLOCK(p->p_pptr);
1553 
1554 				pp = proc_realparent(p);
1555 				proc_reparent(p, pp, false);
1556 				if (pp == initproc)
1557 					p->p_sigparent = SIGCHLD;
1558 				CTR3(KTR_PTRACE,
1559 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1560 				    p->p_pid, pp->p_pid, data);
1561 			} else {
1562 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1563 				    p->p_pid, data);
1564 			}
1565 
1566 			p->p_ptevents = 0;
1567 			FOREACH_THREAD_IN_PROC(p, td3) {
1568 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1569 					sigqueue_delete(&td3->td_sigqueue,
1570 					    SIGSTOP);
1571 				}
1572 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1573 				    TDB_SUSPEND | TDB_BORN);
1574 			}
1575 
1576 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1577 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1578 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1579 			}
1580 
1581 			/*
1582 			 * Send SIGCHLD and wakeup the parent as needed.  It
1583 			 * may be the case that they had stopped the child
1584 			 * before it got ptraced, and now they're in the middle
1585 			 * of a wait(2) for it to continue.
1586 			 */
1587 			PROC_LOCK(p->p_pptr);
1588 			childproc_continued(p);
1589 			PROC_UNLOCK(p->p_pptr);
1590 			break;
1591 		}
1592 
1593 		sx_xunlock(&proctree_lock);
1594 		proctree_locked = false;
1595 
1596 	sendsig:
1597 		MPASS(!proctree_locked);
1598 
1599 		/*
1600 		 * Clear the pending event for the thread that just
1601 		 * reported its event (p_xthread), if any.  This may
1602 		 * not be the thread passed to PT_CONTINUE, PT_STEP,
1603 		 * etc. if the debugger is resuming a different
1604 		 * thread.  There might be no reporting thread if
1605 		 * the process was just attached.
1606 		 *
1607 		 * Deliver any pending signal via the reporting thread.
1608 		 */
1609 		if (p->p_xthread != NULL) {
1610 			p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1611 			p->p_xthread->td_xsig = data;
1612 			p->p_xthread = NULL;
1613 		}
1614 		p->p_xsig = data;
1615 
1616 		/*
1617 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1618 		 * always works immediately, even if another thread is
1619 		 * unsuspended first and attempts to handle a
1620 		 * different signal or if the POSIX.1b style signal
1621 		 * queue cannot accommodate any new signals.
1622 		 */
1623 		if (data == SIGKILL)
1624 			proc_wkilled(p);
1625 
1626 		/*
1627 		 * If the PT_CONTINUE-like operation is attempted on
1628 		 * the thread on sleepq, this is possible only after
1629 		 * the transparent PT_ATTACH.  In this case, if the
1630 		 * caller modified the thread state, e.g. by writing
1631 		 * register file or specifying the pc, make the thread
1632 		 * xstopped by waking it up.
1633 		 */
1634 		if ((td2->td_dbgflags & TDB_USERWR) != 0 &&
1635 		    pt_attach_transparent) {
1636 			thread_lock(td2);
1637 			if (TD_ON_SLEEPQ(td2) &&
1638 			    (td2->td_flags & TDF_SINTR) != 0) {
1639 				td2->td_dbgflags &= ~TDB_USERWR;
1640 				sleepq_abort(td2, EINTR);
1641 			} else {
1642 				thread_unlock(td2);
1643 			}
1644 		}
1645 
1646 		/*
1647 		 * Unsuspend all threads.  To leave a thread
1648 		 * suspended, use PT_SUSPEND to suspend it before
1649 		 * continuing the process.
1650 		 */
1651 		ptrace_unsuspend(p);
1652 		break;
1653 
1654 	case PT_WRITE_I:
1655 	case PT_WRITE_D:
1656 		td2->td_dbgflags |= TDB_USERWR;
1657 		PROC_UNLOCK(p);
1658 		error = 0;
1659 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1660 		    sizeof(int)) != sizeof(int))
1661 			error = ENOMEM;
1662 		else
1663 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1664 			    p->p_pid, addr, data);
1665 		PROC_LOCK(p);
1666 		break;
1667 
1668 	case PT_READ_I:
1669 	case PT_READ_D:
1670 		PROC_UNLOCK(p);
1671 		error = tmp = 0;
1672 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1673 		    sizeof(int)) != sizeof(int))
1674 			error = ENOMEM;
1675 		else
1676 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1677 			    p->p_pid, addr, tmp);
1678 		td->td_retval[0] = tmp;
1679 		PROC_LOCK(p);
1680 		break;
1681 
1682 	case PT_IO:
1683 		piod = addr;
1684 		if (piod->piod_len > SSIZE_MAX) {
1685 			error = EINVAL;
1686 			goto out;
1687 		}
1688 		iov.iov_base = piod->piod_addr;
1689 		iov.iov_len = piod->piod_len;
1690 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1691 		uio.uio_resid = piod->piod_len;
1692 		uio.uio_iov = &iov;
1693 		uio.uio_iovcnt = 1;
1694 		uio.uio_segflg = UIO_USERSPACE;
1695 		uio.uio_td = td;
1696 		switch (piod->piod_op) {
1697 		case PIOD_READ_D:
1698 		case PIOD_READ_I:
1699 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1700 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1701 			uio.uio_rw = UIO_READ;
1702 			break;
1703 		case PIOD_WRITE_D:
1704 		case PIOD_WRITE_I:
1705 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1706 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1707 			td2->td_dbgflags |= TDB_USERWR;
1708 			uio.uio_rw = UIO_WRITE;
1709 			break;
1710 		default:
1711 			error = EINVAL;
1712 			goto out;
1713 		}
1714 		PROC_UNLOCK(p);
1715 		error = proc_rwmem(p, &uio, 0);
1716 		piod->piod_len -= uio.uio_resid;
1717 		PROC_LOCK(p);
1718 		break;
1719 
1720 	case PT_KILL:
1721 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1722 		data = SIGKILL;
1723 		goto sendsig;	/* in PT_CONTINUE above */
1724 
1725 	case PT_SETREGS:
1726 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1727 		    p->p_pid);
1728 		td2->td_dbgflags |= TDB_USERWR;
1729 		error = PROC_WRITE(regs, td2, addr);
1730 		break;
1731 
1732 	case PT_GETREGS:
1733 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1734 		    p->p_pid);
1735 		error = PROC_READ(regs, td2, addr);
1736 		break;
1737 
1738 	case PT_SETFPREGS:
1739 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1740 		    p->p_pid);
1741 		td2->td_dbgflags |= TDB_USERWR;
1742 		error = PROC_WRITE(fpregs, td2, addr);
1743 		break;
1744 
1745 	case PT_GETFPREGS:
1746 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1747 		    p->p_pid);
1748 		error = PROC_READ(fpregs, td2, addr);
1749 		break;
1750 
1751 	case PT_SETDBREGS:
1752 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1753 		    p->p_pid);
1754 		td2->td_dbgflags |= TDB_USERWR;
1755 		error = PROC_WRITE(dbregs, td2, addr);
1756 		break;
1757 
1758 	case PT_GETDBREGS:
1759 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1760 		    p->p_pid);
1761 		error = PROC_READ(dbregs, td2, addr);
1762 		break;
1763 
1764 	case PT_SETREGSET:
1765 		CTR2(KTR_PTRACE, "PT_SETREGSET: tid %d (pid %d)", td2->td_tid,
1766 		    p->p_pid);
1767 		error = proc_write_regset(td2, data, addr);
1768 		break;
1769 
1770 	case PT_GETREGSET:
1771 		CTR2(KTR_PTRACE, "PT_GETREGSET: tid %d (pid %d)", td2->td_tid,
1772 		    p->p_pid);
1773 		error = proc_read_regset(td2, data, addr);
1774 		break;
1775 
1776 	case PT_LWPINFO:
1777 		if (data <= 0 || data > sizeof(*pl)) {
1778 			error = EINVAL;
1779 			break;
1780 		}
1781 		pl = addr;
1782 		bzero(pl, sizeof(*pl));
1783 		pl->pl_lwpid = td2->td_tid;
1784 		pl->pl_event = PL_EVENT_NONE;
1785 		pl->pl_flags = 0;
1786 		if (td2->td_dbgflags & TDB_XSIG) {
1787 			pl->pl_event = PL_EVENT_SIGNAL;
1788 			if (td2->td_si.si_signo != 0 &&
1789 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1790 			    + sizeof(pl->pl_siginfo)){
1791 				pl->pl_flags |= PL_FLAG_SI;
1792 				pl->pl_siginfo = td2->td_si;
1793 			}
1794 		}
1795 		if (td2->td_dbgflags & TDB_SCE)
1796 			pl->pl_flags |= PL_FLAG_SCE;
1797 		else if (td2->td_dbgflags & TDB_SCX)
1798 			pl->pl_flags |= PL_FLAG_SCX;
1799 		if (td2->td_dbgflags & TDB_EXEC)
1800 			pl->pl_flags |= PL_FLAG_EXEC;
1801 		if (td2->td_dbgflags & TDB_FORK) {
1802 			pl->pl_flags |= PL_FLAG_FORKED;
1803 			pl->pl_child_pid = td2->td_dbg_forked;
1804 			if (td2->td_dbgflags & TDB_VFORK)
1805 				pl->pl_flags |= PL_FLAG_VFORKED;
1806 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1807 		    TDB_VFORK)
1808 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1809 		if (td2->td_dbgflags & TDB_CHILD)
1810 			pl->pl_flags |= PL_FLAG_CHILD;
1811 		if (td2->td_dbgflags & TDB_BORN)
1812 			pl->pl_flags |= PL_FLAG_BORN;
1813 		if (td2->td_dbgflags & TDB_EXIT)
1814 			pl->pl_flags |= PL_FLAG_EXITED;
1815 		pl->pl_sigmask = td2->td_sigmask;
1816 		pl->pl_siglist = td2->td_siglist;
1817 		strcpy(pl->pl_tdname, td2->td_name);
1818 		if (td2->td_sa.code != 0) {
1819 			pl->pl_syscall_code = td2->td_sa.code;
1820 			pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1821 		}
1822 		CTR6(KTR_PTRACE,
1823     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1824 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1825 		    pl->pl_child_pid, pl->pl_syscall_code);
1826 		break;
1827 
1828 	case PT_GETNUMLWPS:
1829 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1830 		    p->p_numthreads);
1831 		td->td_retval[0] = p->p_numthreads;
1832 		break;
1833 
1834 	case PT_GETLWPLIST:
1835 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1836 		    p->p_pid, data, p->p_numthreads);
1837 		if (data <= 0) {
1838 			error = EINVAL;
1839 			break;
1840 		}
1841 		num = imin(p->p_numthreads, data);
1842 		PROC_UNLOCK(p);
1843 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1844 		tmp = 0;
1845 		PROC_LOCK(p);
1846 		FOREACH_THREAD_IN_PROC(p, td2) {
1847 			if (tmp >= num)
1848 				break;
1849 			buf[tmp++] = td2->td_tid;
1850 		}
1851 		PROC_UNLOCK(p);
1852 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1853 		free(buf, M_TEMP);
1854 		if (!error)
1855 			td->td_retval[0] = tmp;
1856 		PROC_LOCK(p);
1857 		break;
1858 
1859 	case PT_VM_TIMESTAMP:
1860 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1861 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1862 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1863 		break;
1864 
1865 	case PT_VM_ENTRY:
1866 		PROC_UNLOCK(p);
1867 		error = ptrace_vm_entry(td, p, addr);
1868 		PROC_LOCK(p);
1869 		break;
1870 
1871 	case PT_COREDUMP:
1872 		pc = addr;
1873 		CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1874 		    p->p_pid, pc->pc_fd);
1875 
1876 		if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1877 			error = EINVAL;
1878 			break;
1879 		}
1880 		PROC_UNLOCK(p);
1881 
1882 		tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1883 		fp = NULL;
1884 		error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1885 		if (error != 0)
1886 			goto coredump_cleanup_nofp;
1887 		if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1888 			error = EPIPE;
1889 			goto coredump_cleanup;
1890 		}
1891 
1892 		PROC_LOCK(p);
1893 		error = proc_can_ptrace(td, p);
1894 		if (error != 0)
1895 			goto coredump_cleanup_locked;
1896 
1897 		td2 = ptrace_sel_coredump_thread(p);
1898 		if (td2 == NULL) {
1899 			error = EBUSY;
1900 			goto coredump_cleanup_locked;
1901 		}
1902 		KASSERT((td2->td_dbgflags & (TDB_COREDUMPREQ |
1903 		    TDB_SCREMOTEREQ)) == 0,
1904 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1905 
1906 		tcq->tc_vp = fp->f_vnode;
1907 		tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1908 		tcq->tc_flags = SVC_PT_COREDUMP;
1909 		if ((pc->pc_flags & PC_COMPRESS) == 0)
1910 			tcq->tc_flags |= SVC_NOCOMPRESS;
1911 		if ((pc->pc_flags & PC_ALL) != 0)
1912 			tcq->tc_flags |= SVC_ALL;
1913 		td2->td_remotereq = tcq;
1914 		td2->td_dbgflags |= TDB_COREDUMPREQ;
1915 		thread_run_flash(td2);
1916 		while ((td2->td_dbgflags & TDB_COREDUMPREQ) != 0)
1917 			msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1918 		error = tcq->tc_error;
1919 coredump_cleanup_locked:
1920 		PROC_UNLOCK(p);
1921 coredump_cleanup:
1922 		fdrop(fp, td);
1923 coredump_cleanup_nofp:
1924 		free(tcq, M_TEMP);
1925 		PROC_LOCK(p);
1926 		break;
1927 
1928 	case PT_SC_REMOTE:
1929 		pscr = addr;
1930 		CTR2(KTR_PTRACE, "PT_SC_REMOTE: pid %d, syscall %d",
1931 		    p->p_pid, pscr->pscr_syscall);
1932 		if ((td2->td_dbgflags & TDB_BOUNDARY) == 0) {
1933 			error = EBUSY;
1934 			break;
1935 		}
1936 		PROC_UNLOCK(p);
1937 		MPASS(pscr->pscr_nargs <= nitems(td->td_sa.args));
1938 
1939 		tsr = malloc(sizeof(struct thr_syscall_req), M_TEMP,
1940 		    M_WAITOK | M_ZERO);
1941 
1942 		tsr->ts_sa.code = pscr->pscr_syscall;
1943 		tsr->ts_nargs = pscr->pscr_nargs;
1944 		memcpy(&tsr->ts_sa.args, pscr->pscr_args,
1945 		    sizeof(syscallarg_t) * tsr->ts_nargs);
1946 
1947 		PROC_LOCK(p);
1948 		error = proc_can_ptrace(td, p);
1949 		if (error != 0) {
1950 			free(tsr, M_TEMP);
1951 			break;
1952 		}
1953 		if (td2->td_proc != p) {
1954 			free(tsr, M_TEMP);
1955 			error = ESRCH;
1956 			break;
1957 		}
1958 		KASSERT((td2->td_dbgflags & (TDB_COREDUMPREQ |
1959 		    TDB_SCREMOTEREQ)) == 0,
1960 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1961 
1962 		td2->td_remotereq = tsr;
1963 		td2->td_dbgflags |= TDB_SCREMOTEREQ;
1964 		thread_run_flash(td2);
1965 		while ((td2->td_dbgflags & TDB_SCREMOTEREQ) != 0)
1966 			msleep(p, &p->p_mtx, PPAUSE, "pscrx", 0);
1967 		error = 0;
1968 		memcpy(&pscr->pscr_ret, &tsr->ts_ret, sizeof(tsr->ts_ret));
1969 		free(tsr, M_TEMP);
1970 		break;
1971 
1972 	case PT_GET_CHILDREN:
1973 		PROC_UNLOCK(p);
1974 get_children_repeat:
1975 		/*
1976 		 * If addr != NULL, we should ignore p_cansee() to
1977 		 * allocate enough space for the children array,
1978 		 * because the process is allowed to change visibility
1979 		 * between loops.  But do not count children which
1980 		 * we cannot see when only returning the count, to
1981 		 * avoid a leak of information.
1982 		 */
1983 		num = ptrace_count_children(td, p, addr != NULL);
1984 
1985 		if (addr == NULL) {
1986 			td->td_retval[0] = num;
1987 			PROC_LOCK(p);
1988 			break;
1989 		}
1990 		if (data < num * sizeof(struct ptrace_child)) {
1991 			error = ENOMEM;
1992 			PROC_LOCK(p);
1993 			break;
1994 		}
1995 		sx_xunlock(&proctree_lock);
1996 		children = mallocarray(num, sizeof(struct ptrace_child),
1997 		    M_TEMP, M_WAITOK | M_ZERO);
1998 		sx_xlock(&proctree_lock);
1999 		num1 = ptrace_count_children(td, p, true);
2000 		if (num1 > num) {
2001 			free(children, M_TEMP);
2002 			goto get_children_repeat;
2003 		}
2004 		num = num1;
2005 		num1 = 0;
2006 		LIST_FOREACH(pp, &p->p_children, p_sibling) {
2007 			MPASS(num1 < num);
2008 			ptc = &children[num1];
2009 			if (ptrace_report_child(td, p, pp, ptc))
2010 				num1++;
2011 		}
2012 		LIST_FOREACH(pp, &p->p_orphans, p_orphan) {
2013 			MPASS(num1 < num);
2014 			ptc = &children[num1];
2015 			if (ptrace_report_child(td, p, pp, ptc)) {
2016 				num1++;
2017 				ptc->flags |= PTCHLD_ORPHAN;
2018 			}
2019 		}
2020 		*(struct ptrace_child **)addr = children;
2021 		td->td_retval[0] = num1;
2022 		PROC_LOCK(p);
2023 		break;
2024 
2025 	case PT_GET_ABI_NAME:
2026 		if (strlcpy(addr, p->p_sysent->sv_name, data) >= data)
2027 			error = ENOMEM;
2028 		break;
2029 
2030 	default:
2031 #ifdef __HAVE_PTRACE_MACHDEP
2032 		if (req >= PT_FIRSTMACH) {
2033 			PROC_UNLOCK(p);
2034 			error = cpu_ptrace(td2, req, addr, data);
2035 			PROC_LOCK(p);
2036 		} else
2037 #endif
2038 			/* Unknown request. */
2039 			error = EINVAL;
2040 		break;
2041 	}
2042 out:
2043 	/* Drop our hold on this process now that the request has completed. */
2044 	_PRELE(p);
2045 fail:
2046 	if (p2_req_set) {
2047 		if ((p->p_flag2 & P2_PTRACEREQ) != 0)
2048 			wakeup(&p->p_flag2);
2049 		p->p_flag2 &= ~P2_PTRACEREQ;
2050 	}
2051 	PROC_UNLOCK(p);
2052 fail_proctree:
2053 	if (proctree_locked)
2054 		sx_xunlock(&proctree_lock);
2055 	if (pfp != NULL)
2056 		fdrop(pfp, td);
2057 	return (error);
2058 }
2059 #undef PROC_READ
2060 #undef PROC_WRITE
2061 
2062 int
2063 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
2064 {
2065 	return (ptrace_action(td, req, false, pid, -1, -1, addr, data));
2066 }
2067 
2068 int
2069 sys_ptrace(struct thread *td, struct ptrace_args *uap)
2070 {
2071 	int error;
2072 
2073 	AUDIT_ARG_PID(uap->pid);
2074 	AUDIT_ARG_CMD(uap->req);
2075 	AUDIT_ARG_VALUE(uap->data);
2076 
2077 	error = ptrace_useraction(td, uap->req, false, uap->pid, -1, -1,
2078 	    uap->addr, uap->data);
2079 	return (error);
2080 }
2081 
2082 int
2083 sys_pdptrace(struct thread *td, struct pdptrace_args *uap)
2084 {
2085 	int error;
2086 
2087 	AUDIT_ARG_FD(uap->pfd);
2088 	AUDIT_ARG_CMD(uap->req);
2089 	AUDIT_ARG_VALUE(uap->data);
2090 
2091 	error = ptrace_useraction(td, uap->req, true, -1, uap->pfd, uap->lwpid,
2092 	    uap->addr, uap->data);
2093 	return (error);
2094 }
2095