xref: /freebsd/sys/kern/sys_process.c (revision 4a27bf128b108d90412190c06a54ebac36a8ca2e)
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/syscallsubr.h>
44 #include <sys/sysent.h>
45 #include <sys/sysproto.h>
46 #include <sys/priv.h>
47 #include <sys/proc.h>
48 #include <sys/vnode.h>
49 #include <sys/ptrace.h>
50 #include <sys/rwlock.h>
51 #include <sys/sx.h>
52 #include <sys/malloc.h>
53 #include <sys/signalvar.h>
54 #include <sys/caprights.h>
55 #include <sys/filedesc.h>
56 
57 #include <machine/reg.h>
58 
59 #include <security/audit/audit.h>
60 
61 #include <vm/vm.h>
62 #include <vm/pmap.h>
63 #include <vm/vm_extern.h>
64 #include <vm/vm_map.h>
65 #include <vm/vm_kern.h>
66 #include <vm/vm_object.h>
67 #include <vm/vm_page.h>
68 #include <vm/vm_param.h>
69 
70 #ifdef COMPAT_FREEBSD32
71 #include <sys/procfs.h>
72 #endif
73 
74 /*
75  * Functions implemented using PROC_ACTION():
76  *
77  * proc_read_regs(proc, regs)
78  *	Get the current user-visible register set from the process
79  *	and copy it into the regs structure (<machine/reg.h>).
80  *	The process is stopped at the time read_regs is called.
81  *
82  * proc_write_regs(proc, regs)
83  *	Update the current register set from the passed in regs
84  *	structure.  Take care to avoid clobbering special CPU
85  *	registers or privileged bits in the PSL.
86  *	Depending on the architecture this may have fix-up work to do,
87  *	especially if the IAR or PCW are modified.
88  *	The process is stopped at the time write_regs is called.
89  *
90  * proc_read_fpregs, proc_write_fpregs
91  *	deal with the floating point register set, otherwise as above.
92  *
93  * proc_read_dbregs, proc_write_dbregs
94  *	deal with the processor debug register set, otherwise as above.
95  *
96  * proc_sstep(proc)
97  *	Arrange for the process to trap after executing a single instruction.
98  */
99 
100 #define	PROC_ACTION(action) do {					\
101 	int error;							\
102 									\
103 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
104 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
105 		error = EIO;						\
106 	else								\
107 		error = (action);					\
108 	return (error);							\
109 } while (0)
110 
111 int
112 proc_read_regs(struct thread *td, struct reg *regs)
113 {
114 
115 	PROC_ACTION(fill_regs(td, regs));
116 }
117 
118 int
119 proc_write_regs(struct thread *td, struct reg *regs)
120 {
121 
122 	PROC_ACTION(set_regs(td, regs));
123 }
124 
125 int
126 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
127 {
128 
129 	PROC_ACTION(fill_dbregs(td, dbregs));
130 }
131 
132 int
133 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
134 {
135 
136 	PROC_ACTION(set_dbregs(td, dbregs));
137 }
138 
139 /*
140  * Ptrace doesn't support fpregs at all, and there are no security holes
141  * or translations for fpregs, so we can just copy them.
142  */
143 int
144 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
145 {
146 
147 	PROC_ACTION(fill_fpregs(td, fpregs));
148 }
149 
150 int
151 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
152 {
153 
154 	PROC_ACTION(set_fpregs(td, fpregs));
155 }
156 
157 #ifdef COMPAT_FREEBSD32
158 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
159 int
160 proc_read_regs32(struct thread *td, struct reg32 *regs32)
161 {
162 
163 	PROC_ACTION(fill_regs32(td, regs32));
164 }
165 
166 int
167 proc_write_regs32(struct thread *td, struct reg32 *regs32)
168 {
169 
170 	PROC_ACTION(set_regs32(td, regs32));
171 }
172 
173 int
174 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
175 {
176 
177 	PROC_ACTION(fill_dbregs32(td, dbregs32));
178 }
179 
180 int
181 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
182 {
183 
184 	PROC_ACTION(set_dbregs32(td, dbregs32));
185 }
186 
187 int
188 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
189 {
190 
191 	PROC_ACTION(fill_fpregs32(td, fpregs32));
192 }
193 
194 int
195 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
196 {
197 
198 	PROC_ACTION(set_fpregs32(td, fpregs32));
199 }
200 #endif
201 
202 int
203 proc_sstep(struct thread *td)
204 {
205 
206 	PROC_ACTION(ptrace_single_step(td));
207 }
208 
209 int
210 proc_rwmem(struct proc *p, struct uio *uio)
211 {
212 	vm_map_t map;
213 	vm_offset_t pageno;		/* page number */
214 	vm_prot_t reqprot;
215 	int error, fault_flags, page_offset, writing;
216 
217 	/*
218 	 * Assert that someone has locked this vmspace.  (Should be
219 	 * curthread but we can't assert that.)  This keeps the process
220 	 * from exiting out from under us until this operation completes.
221 	 */
222 	PROC_ASSERT_HELD(p);
223 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
224 
225 	/*
226 	 * The map we want...
227 	 */
228 	map = &p->p_vmspace->vm_map;
229 
230 	/*
231 	 * If we are writing, then we request vm_fault() to create a private
232 	 * copy of each page.  Since these copies will not be writeable by the
233 	 * process, we must explicity request that they be dirtied.
234 	 */
235 	writing = uio->uio_rw == UIO_WRITE;
236 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
237 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
238 
239 	/*
240 	 * Only map in one page at a time.  We don't have to, but it
241 	 * makes things easier.  This way is trivial - right?
242 	 */
243 	do {
244 		vm_offset_t uva;
245 		u_int len;
246 		vm_page_t m;
247 
248 		uva = (vm_offset_t)uio->uio_offset;
249 
250 		/*
251 		 * Get the page number of this segment.
252 		 */
253 		pageno = trunc_page(uva);
254 		page_offset = uva - pageno;
255 
256 		/*
257 		 * How many bytes to copy
258 		 */
259 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
260 
261 		/*
262 		 * Fault and hold the page on behalf of the process.
263 		 */
264 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
265 		if (error != KERN_SUCCESS) {
266 			if (error == KERN_RESOURCE_SHORTAGE)
267 				error = ENOMEM;
268 			else
269 				error = EFAULT;
270 			break;
271 		}
272 
273 		/*
274 		 * Now do the i/o move.
275 		 */
276 		error = uiomove_fromphys(&m, page_offset, len, uio);
277 
278 		/* Make the I-cache coherent for breakpoints. */
279 		if (writing && error == 0) {
280 			vm_map_lock_read(map);
281 			if (vm_map_check_protection(map, pageno, pageno +
282 			    PAGE_SIZE, VM_PROT_EXECUTE))
283 				vm_sync_icache(map, uva, len);
284 			vm_map_unlock_read(map);
285 		}
286 
287 		/*
288 		 * Release the page.
289 		 */
290 		vm_page_unwire(m, PQ_ACTIVE);
291 
292 	} while (error == 0 && uio->uio_resid > 0);
293 
294 	return (error);
295 }
296 
297 static ssize_t
298 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
299     size_t len, enum uio_rw rw)
300 {
301 	struct iovec iov;
302 	struct uio uio;
303 	ssize_t slen;
304 
305 	MPASS(len < SSIZE_MAX);
306 	slen = (ssize_t)len;
307 
308 	iov.iov_base = (caddr_t)buf;
309 	iov.iov_len = len;
310 	uio.uio_iov = &iov;
311 	uio.uio_iovcnt = 1;
312 	uio.uio_offset = va;
313 	uio.uio_resid = slen;
314 	uio.uio_segflg = UIO_SYSSPACE;
315 	uio.uio_rw = rw;
316 	uio.uio_td = td;
317 	proc_rwmem(p, &uio);
318 	if (uio.uio_resid == slen)
319 		return (-1);
320 	return (slen - uio.uio_resid);
321 }
322 
323 ssize_t
324 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
325     size_t len)
326 {
327 
328 	return (proc_iop(td, p, va, buf, len, UIO_READ));
329 }
330 
331 ssize_t
332 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
333     size_t len)
334 {
335 
336 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
337 }
338 
339 static int
340 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
341 {
342 	struct vattr vattr;
343 	vm_map_t map;
344 	vm_map_entry_t entry;
345 	vm_object_t obj, tobj, lobj;
346 	struct vmspace *vm;
347 	struct vnode *vp;
348 	char *freepath, *fullpath;
349 	u_int pathlen;
350 	int error, index;
351 
352 	error = 0;
353 	obj = NULL;
354 
355 	vm = vmspace_acquire_ref(p);
356 	map = &vm->vm_map;
357 	vm_map_lock_read(map);
358 
359 	do {
360 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
361 		    ("Submap in map header"));
362 		index = 0;
363 		VM_MAP_ENTRY_FOREACH(entry, map) {
364 			if (index >= pve->pve_entry &&
365 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
366 				break;
367 			index++;
368 		}
369 		if (index < pve->pve_entry) {
370 			error = EINVAL;
371 			break;
372 		}
373 		if (entry == &map->header) {
374 			error = ENOENT;
375 			break;
376 		}
377 
378 		/* We got an entry. */
379 		pve->pve_entry = index + 1;
380 		pve->pve_timestamp = map->timestamp;
381 		pve->pve_start = entry->start;
382 		pve->pve_end = entry->end - 1;
383 		pve->pve_offset = entry->offset;
384 		pve->pve_prot = entry->protection;
385 
386 		/* Backing object's path needed? */
387 		if (pve->pve_pathlen == 0)
388 			break;
389 
390 		pathlen = pve->pve_pathlen;
391 		pve->pve_pathlen = 0;
392 
393 		obj = entry->object.vm_object;
394 		if (obj != NULL)
395 			VM_OBJECT_RLOCK(obj);
396 	} while (0);
397 
398 	vm_map_unlock_read(map);
399 
400 	pve->pve_fsid = VNOVAL;
401 	pve->pve_fileid = VNOVAL;
402 
403 	if (error == 0 && obj != NULL) {
404 		lobj = obj;
405 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
406 			if (tobj != obj)
407 				VM_OBJECT_RLOCK(tobj);
408 			if (lobj != obj)
409 				VM_OBJECT_RUNLOCK(lobj);
410 			lobj = tobj;
411 			pve->pve_offset += tobj->backing_object_offset;
412 		}
413 		vp = vm_object_vnode(lobj);
414 		if (vp != NULL)
415 			vref(vp);
416 		if (lobj != obj)
417 			VM_OBJECT_RUNLOCK(lobj);
418 		VM_OBJECT_RUNLOCK(obj);
419 
420 		if (vp != NULL) {
421 			freepath = NULL;
422 			fullpath = NULL;
423 			vn_fullpath(vp, &fullpath, &freepath);
424 			vn_lock(vp, LK_SHARED | LK_RETRY);
425 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
426 				pve->pve_fileid = vattr.va_fileid;
427 				pve->pve_fsid = vattr.va_fsid;
428 			}
429 			vput(vp);
430 
431 			if (fullpath != NULL) {
432 				pve->pve_pathlen = strlen(fullpath) + 1;
433 				if (pve->pve_pathlen <= pathlen) {
434 					error = copyout(fullpath, pve->pve_path,
435 					    pve->pve_pathlen);
436 				} else
437 					error = ENAMETOOLONG;
438 			}
439 			if (freepath != NULL)
440 				free(freepath, M_TEMP);
441 		}
442 	}
443 	vmspace_free(vm);
444 	if (error == 0)
445 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
446 		    p->p_pid, pve->pve_entry, pve->pve_start);
447 
448 	return (error);
449 }
450 
451 /*
452  * Process debugging system call.
453  */
454 #ifndef _SYS_SYSPROTO_H_
455 struct ptrace_args {
456 	int	req;
457 	pid_t	pid;
458 	caddr_t	addr;
459 	int	data;
460 };
461 #endif
462 
463 int
464 sys_ptrace(struct thread *td, struct ptrace_args *uap)
465 {
466 	/*
467 	 * XXX this obfuscation is to reduce stack usage, but the register
468 	 * structs may be too large to put on the stack anyway.
469 	 */
470 	union {
471 		struct ptrace_io_desc piod;
472 		struct ptrace_lwpinfo pl;
473 		struct ptrace_vm_entry pve;
474 		struct ptrace_coredump pc;
475 		struct dbreg dbreg;
476 		struct fpreg fpreg;
477 		struct reg reg;
478 		char args[sizeof(td->td_sa.args)];
479 		struct ptrace_sc_ret psr;
480 		int ptevents;
481 	} r;
482 	void *addr;
483 	int error = 0;
484 
485 	AUDIT_ARG_PID(uap->pid);
486 	AUDIT_ARG_CMD(uap->req);
487 	AUDIT_ARG_VALUE(uap->data);
488 	addr = &r;
489 	switch (uap->req) {
490 	case PT_GET_EVENT_MASK:
491 	case PT_LWPINFO:
492 	case PT_GET_SC_ARGS:
493 	case PT_GET_SC_RET:
494 		break;
495 	case PT_GETREGS:
496 		bzero(&r.reg, sizeof(r.reg));
497 		break;
498 	case PT_GETFPREGS:
499 		bzero(&r.fpreg, sizeof(r.fpreg));
500 		break;
501 	case PT_GETDBREGS:
502 		bzero(&r.dbreg, sizeof(r.dbreg));
503 		break;
504 	case PT_SETREGS:
505 		error = copyin(uap->addr, &r.reg, sizeof(r.reg));
506 		break;
507 	case PT_SETFPREGS:
508 		error = copyin(uap->addr, &r.fpreg, sizeof(r.fpreg));
509 		break;
510 	case PT_SETDBREGS:
511 		error = copyin(uap->addr, &r.dbreg, sizeof(r.dbreg));
512 		break;
513 	case PT_SET_EVENT_MASK:
514 		if (uap->data != sizeof(r.ptevents))
515 			error = EINVAL;
516 		else
517 			error = copyin(uap->addr, &r.ptevents, uap->data);
518 		break;
519 	case PT_IO:
520 		error = copyin(uap->addr, &r.piod, sizeof(r.piod));
521 		break;
522 	case PT_VM_ENTRY:
523 		error = copyin(uap->addr, &r.pve, sizeof(r.pve));
524 		break;
525 	case PT_COREDUMP:
526 		if (uap->data != sizeof(r.pc))
527 			error = EINVAL;
528 		else
529 			error = copyin(uap->addr, &r.pc, uap->data);
530 		break;
531 	default:
532 		addr = uap->addr;
533 		break;
534 	}
535 	if (error)
536 		return (error);
537 
538 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
539 	if (error)
540 		return (error);
541 
542 	switch (uap->req) {
543 	case PT_VM_ENTRY:
544 		error = copyout(&r.pve, uap->addr, sizeof(r.pve));
545 		break;
546 	case PT_IO:
547 		error = copyout(&r.piod, uap->addr, sizeof(r.piod));
548 		break;
549 	case PT_GETREGS:
550 		error = copyout(&r.reg, uap->addr, sizeof(r.reg));
551 		break;
552 	case PT_GETFPREGS:
553 		error = copyout(&r.fpreg, uap->addr, sizeof(r.fpreg));
554 		break;
555 	case PT_GETDBREGS:
556 		error = copyout(&r.dbreg, uap->addr, sizeof(r.dbreg));
557 		break;
558 	case PT_GET_EVENT_MASK:
559 		/* NB: The size in uap->data is validated in kern_ptrace(). */
560 		error = copyout(&r.ptevents, uap->addr, uap->data);
561 		break;
562 	case PT_LWPINFO:
563 		/* NB: The size in uap->data is validated in kern_ptrace(). */
564 		error = copyout(&r.pl, uap->addr, uap->data);
565 		break;
566 	case PT_GET_SC_ARGS:
567 		error = copyout(r.args, uap->addr, MIN(uap->data,
568 		    sizeof(r.args)));
569 		break;
570 	case PT_GET_SC_RET:
571 		error = copyout(&r.psr, uap->addr, MIN(uap->data,
572 		    sizeof(r.psr)));
573 		break;
574 	}
575 
576 	return (error);
577 }
578 
579 #ifdef COMPAT_FREEBSD32
580 /*
581  *   PROC_READ(regs, td2, addr);
582  * becomes either:
583  *   proc_read_regs(td2, addr);
584  * or
585  *   proc_read_regs32(td2, addr);
586  * .. except this is done at runtime.  There is an additional
587  * complication in that PROC_WRITE disallows 32 bit consumers
588  * from writing to 64 bit address space targets.
589  */
590 #define	PROC_READ(w, t, a)	wrap32 ? \
591 	proc_read_ ## w ## 32(t, a) : \
592 	proc_read_ ## w (t, a)
593 #define	PROC_WRITE(w, t, a)	wrap32 ? \
594 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
595 	proc_write_ ## w (t, a)
596 #else
597 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
598 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
599 #endif
600 
601 void
602 proc_set_traced(struct proc *p, bool stop)
603 {
604 
605 	sx_assert(&proctree_lock, SX_XLOCKED);
606 	PROC_LOCK_ASSERT(p, MA_OWNED);
607 	p->p_flag |= P_TRACED;
608 	if (stop)
609 		p->p_flag2 |= P2_PTRACE_FSTP;
610 	p->p_ptevents = PTRACE_DEFAULT;
611 }
612 
613 static int
614 proc_can_ptrace(struct thread *td, struct proc *p)
615 {
616 	int error;
617 
618 	PROC_LOCK_ASSERT(p, MA_OWNED);
619 
620 	if ((p->p_flag & P_WEXIT) != 0)
621 		return (ESRCH);
622 
623 	if ((error = p_cansee(td, p)) != 0)
624 		return (error);
625 	if ((error = p_candebug(td, p)) != 0)
626 		return (error);
627 
628 	/* not being traced... */
629 	if ((p->p_flag & P_TRACED) == 0)
630 		return (EPERM);
631 
632 	/* not being traced by YOU */
633 	if (p->p_pptr != td->td_proc)
634 		return (EBUSY);
635 
636 	/* not currently stopped */
637 	if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
638 	    p->p_suspcount != p->p_numthreads  ||
639 	    (p->p_flag & P_WAITED) == 0)
640 		return (EBUSY);
641 
642 	return (0);
643 }
644 
645 static struct thread *
646 ptrace_sel_coredump_thread(struct proc *p)
647 {
648 	struct thread *td2;
649 
650 	PROC_LOCK_ASSERT(p, MA_OWNED);
651 	MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
652 
653 	FOREACH_THREAD_IN_PROC(p, td2) {
654 		if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
655 			return (td2);
656 	}
657 	return (NULL);
658 }
659 
660 int
661 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
662 {
663 	struct iovec iov;
664 	struct uio uio;
665 	struct proc *curp, *p, *pp;
666 	struct thread *td2 = NULL, *td3;
667 	struct ptrace_io_desc *piod = NULL;
668 	struct ptrace_lwpinfo *pl;
669 	struct ptrace_sc_ret *psr;
670 	struct file *fp;
671 	struct ptrace_coredump *pc;
672 	struct thr_coredump_req *tcq;
673 	int error, num, tmp;
674 	lwpid_t tid = 0, *buf;
675 #ifdef COMPAT_FREEBSD32
676 	int wrap32 = 0, safe = 0;
677 #endif
678 	bool proctree_locked, p2_req_set;
679 
680 	curp = td->td_proc;
681 	proctree_locked = false;
682 	p2_req_set = false;
683 
684 	/* Lock proctree before locking the process. */
685 	switch (req) {
686 	case PT_TRACE_ME:
687 	case PT_ATTACH:
688 	case PT_STEP:
689 	case PT_CONTINUE:
690 	case PT_TO_SCE:
691 	case PT_TO_SCX:
692 	case PT_SYSCALL:
693 	case PT_FOLLOW_FORK:
694 	case PT_LWP_EVENTS:
695 	case PT_GET_EVENT_MASK:
696 	case PT_SET_EVENT_MASK:
697 	case PT_DETACH:
698 	case PT_GET_SC_ARGS:
699 		sx_xlock(&proctree_lock);
700 		proctree_locked = true;
701 		break;
702 	default:
703 		break;
704 	}
705 
706 	if (req == PT_TRACE_ME) {
707 		p = td->td_proc;
708 		PROC_LOCK(p);
709 	} else {
710 		if (pid <= PID_MAX) {
711 			if ((p = pfind(pid)) == NULL) {
712 				if (proctree_locked)
713 					sx_xunlock(&proctree_lock);
714 				return (ESRCH);
715 			}
716 		} else {
717 			td2 = tdfind(pid, -1);
718 			if (td2 == NULL) {
719 				if (proctree_locked)
720 					sx_xunlock(&proctree_lock);
721 				return (ESRCH);
722 			}
723 			p = td2->td_proc;
724 			tid = pid;
725 			pid = p->p_pid;
726 		}
727 	}
728 	AUDIT_ARG_PROCESS(p);
729 
730 	if ((p->p_flag & P_WEXIT) != 0) {
731 		error = ESRCH;
732 		goto fail;
733 	}
734 	if ((error = p_cansee(td, p)) != 0)
735 		goto fail;
736 
737 	if ((error = p_candebug(td, p)) != 0)
738 		goto fail;
739 
740 	/*
741 	 * System processes can't be debugged.
742 	 */
743 	if ((p->p_flag & P_SYSTEM) != 0) {
744 		error = EINVAL;
745 		goto fail;
746 	}
747 
748 	if (tid == 0) {
749 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
750 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
751 			td2 = p->p_xthread;
752 		} else {
753 			td2 = FIRST_THREAD_IN_PROC(p);
754 		}
755 		tid = td2->td_tid;
756 	}
757 
758 #ifdef COMPAT_FREEBSD32
759 	/*
760 	 * Test if we're a 32 bit client and what the target is.
761 	 * Set the wrap controls accordingly.
762 	 */
763 	if (SV_CURPROC_FLAG(SV_ILP32)) {
764 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
765 			safe = 1;
766 		wrap32 = 1;
767 	}
768 #endif
769 	/*
770 	 * Permissions check
771 	 */
772 	switch (req) {
773 	case PT_TRACE_ME:
774 		/*
775 		 * Always legal, when there is a parent process which
776 		 * could trace us.  Otherwise, reject.
777 		 */
778 		if ((p->p_flag & P_TRACED) != 0) {
779 			error = EBUSY;
780 			goto fail;
781 		}
782 		if (p->p_pptr == initproc) {
783 			error = EPERM;
784 			goto fail;
785 		}
786 		break;
787 
788 	case PT_ATTACH:
789 		/* Self */
790 		if (p == td->td_proc) {
791 			error = EINVAL;
792 			goto fail;
793 		}
794 
795 		/* Already traced */
796 		if (p->p_flag & P_TRACED) {
797 			error = EBUSY;
798 			goto fail;
799 		}
800 
801 		/* Can't trace an ancestor if you're being traced. */
802 		if (curp->p_flag & P_TRACED) {
803 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
804 				if (pp == p) {
805 					error = EINVAL;
806 					goto fail;
807 				}
808 			}
809 		}
810 
811 		/* OK */
812 		break;
813 
814 	case PT_CLEARSTEP:
815 		/* Allow thread to clear single step for itself */
816 		if (td->td_tid == tid)
817 			break;
818 
819 		/* FALLTHROUGH */
820 	default:
821 		/*
822 		 * Check for ptrace eligibility before waiting for
823 		 * holds to drain.
824 		 */
825 		error = proc_can_ptrace(td, p);
826 		if (error != 0)
827 			goto fail;
828 
829 		/*
830 		 * Block parallel ptrace requests.  Most important, do
831 		 * not allow other thread in debugger to continue the
832 		 * debuggee until coredump finished.
833 		 */
834 		while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
835 			if (proctree_locked)
836 				sx_xunlock(&proctree_lock);
837 			error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
838 			    (proctree_locked ? PDROP : 0), "pptrace", 0);
839 			if (proctree_locked) {
840 				sx_xlock(&proctree_lock);
841 				PROC_LOCK(p);
842 			}
843 			if (error == 0 && td2->td_proc != p)
844 				error = ESRCH;
845 			if (error == 0)
846 				error = proc_can_ptrace(td, p);
847 			if (error != 0)
848 				goto fail;
849 		}
850 
851 		/* Ok */
852 		break;
853 	}
854 
855 	/*
856 	 * Keep this process around and request parallel ptrace()
857 	 * request to wait until we finish this request.
858 	 */
859 	MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
860 	p->p_flag2 |= P2_PTRACEREQ;
861 	p2_req_set = true;
862 	_PHOLD(p);
863 
864 	/*
865 	 * Actually do the requests
866 	 */
867 
868 	td->td_retval[0] = 0;
869 
870 	switch (req) {
871 	case PT_TRACE_ME:
872 		/* set my trace flag and "owner" so it can read/write me */
873 		proc_set_traced(p, false);
874 		if (p->p_flag & P_PPWAIT)
875 			p->p_flag |= P_PPTRACE;
876 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
877 		break;
878 
879 	case PT_ATTACH:
880 		/* security check done above */
881 		/*
882 		 * It would be nice if the tracing relationship was separate
883 		 * from the parent relationship but that would require
884 		 * another set of links in the proc struct or for "wait"
885 		 * to scan the entire proc table.  To make life easier,
886 		 * we just re-parent the process we're trying to trace.
887 		 * The old parent is remembered so we can put things back
888 		 * on a "detach".
889 		 */
890 		proc_set_traced(p, true);
891 		proc_reparent(p, td->td_proc, false);
892 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
893 		    p->p_oppid);
894 
895 		sx_xunlock(&proctree_lock);
896 		proctree_locked = false;
897 		MPASS(p->p_xthread == NULL);
898 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
899 
900 		/*
901 		 * If already stopped due to a stop signal, clear the
902 		 * existing stop before triggering a traced SIGSTOP.
903 		 */
904 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
905 			PROC_SLOCK(p);
906 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
907 			thread_unsuspend(p);
908 			PROC_SUNLOCK(p);
909 		}
910 
911 		kern_psignal(p, SIGSTOP);
912 		break;
913 
914 	case PT_CLEARSTEP:
915 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
916 		    p->p_pid);
917 		error = ptrace_clear_single_step(td2);
918 		break;
919 
920 	case PT_SETSTEP:
921 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
922 		    p->p_pid);
923 		error = ptrace_single_step(td2);
924 		break;
925 
926 	case PT_SUSPEND:
927 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
928 		    p->p_pid);
929 		td2->td_dbgflags |= TDB_SUSPEND;
930 		thread_lock(td2);
931 		td2->td_flags |= TDF_NEEDSUSPCHK;
932 		thread_unlock(td2);
933 		break;
934 
935 	case PT_RESUME:
936 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
937 		    p->p_pid);
938 		td2->td_dbgflags &= ~TDB_SUSPEND;
939 		break;
940 
941 	case PT_FOLLOW_FORK:
942 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
943 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
944 		    data ? "enabled" : "disabled");
945 		if (data)
946 			p->p_ptevents |= PTRACE_FORK;
947 		else
948 			p->p_ptevents &= ~PTRACE_FORK;
949 		break;
950 
951 	case PT_LWP_EVENTS:
952 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
953 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
954 		    data ? "enabled" : "disabled");
955 		if (data)
956 			p->p_ptevents |= PTRACE_LWP;
957 		else
958 			p->p_ptevents &= ~PTRACE_LWP;
959 		break;
960 
961 	case PT_GET_EVENT_MASK:
962 		if (data != sizeof(p->p_ptevents)) {
963 			error = EINVAL;
964 			break;
965 		}
966 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
967 		    p->p_ptevents);
968 		*(int *)addr = p->p_ptevents;
969 		break;
970 
971 	case PT_SET_EVENT_MASK:
972 		if (data != sizeof(p->p_ptevents)) {
973 			error = EINVAL;
974 			break;
975 		}
976 		tmp = *(int *)addr;
977 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
978 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
979 			error = EINVAL;
980 			break;
981 		}
982 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
983 		    p->p_pid, p->p_ptevents, tmp);
984 		p->p_ptevents = tmp;
985 		break;
986 
987 	case PT_GET_SC_ARGS:
988 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
989 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
990 #ifdef COMPAT_FREEBSD32
991 		    || (wrap32 && !safe)
992 #endif
993 		    ) {
994 			error = EINVAL;
995 			break;
996 		}
997 		bzero(addr, sizeof(td2->td_sa.args));
998 		bcopy(td2->td_sa.args, addr, td2->td_sa.callp->sy_narg *
999 		    sizeof(register_t));
1000 		break;
1001 
1002 	case PT_GET_SC_RET:
1003 		if ((td2->td_dbgflags & (TDB_SCX)) == 0
1004 #ifdef COMPAT_FREEBSD32
1005 		    || (wrap32 && !safe)
1006 #endif
1007 		    ) {
1008 			error = EINVAL;
1009 			break;
1010 		}
1011 		psr = addr;
1012 		bzero(psr, sizeof(*psr));
1013 		psr->sr_error = td2->td_errno;
1014 		if (psr->sr_error == 0) {
1015 			psr->sr_retval[0] = td2->td_retval[0];
1016 			psr->sr_retval[1] = td2->td_retval[1];
1017 		}
1018 		CTR4(KTR_PTRACE,
1019 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1020 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1021 		    psr->sr_retval[1]);
1022 		break;
1023 
1024 	case PT_STEP:
1025 	case PT_CONTINUE:
1026 	case PT_TO_SCE:
1027 	case PT_TO_SCX:
1028 	case PT_SYSCALL:
1029 	case PT_DETACH:
1030 		/* Zero means do not send any signal */
1031 		if (data < 0 || data > _SIG_MAXSIG) {
1032 			error = EINVAL;
1033 			break;
1034 		}
1035 
1036 		switch (req) {
1037 		case PT_STEP:
1038 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1039 			    td2->td_tid, p->p_pid, data);
1040 			error = ptrace_single_step(td2);
1041 			if (error)
1042 				goto out;
1043 			break;
1044 		case PT_CONTINUE:
1045 		case PT_TO_SCE:
1046 		case PT_TO_SCX:
1047 		case PT_SYSCALL:
1048 			if (addr != (void *)1) {
1049 				error = ptrace_set_pc(td2,
1050 				    (u_long)(uintfptr_t)addr);
1051 				if (error)
1052 					goto out;
1053 			}
1054 			switch (req) {
1055 			case PT_TO_SCE:
1056 				p->p_ptevents |= PTRACE_SCE;
1057 				CTR4(KTR_PTRACE,
1058 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1059 				    p->p_pid, p->p_ptevents,
1060 				    (u_long)(uintfptr_t)addr, data);
1061 				break;
1062 			case PT_TO_SCX:
1063 				p->p_ptevents |= PTRACE_SCX;
1064 				CTR4(KTR_PTRACE,
1065 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1066 				    p->p_pid, p->p_ptevents,
1067 				    (u_long)(uintfptr_t)addr, data);
1068 				break;
1069 			case PT_SYSCALL:
1070 				p->p_ptevents |= PTRACE_SYSCALL;
1071 				CTR4(KTR_PTRACE,
1072 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1073 				    p->p_pid, p->p_ptevents,
1074 				    (u_long)(uintfptr_t)addr, data);
1075 				break;
1076 			case PT_CONTINUE:
1077 				CTR3(KTR_PTRACE,
1078 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1079 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1080 				break;
1081 			}
1082 			break;
1083 		case PT_DETACH:
1084 			/*
1085 			 * Clear P_TRACED before reparenting
1086 			 * a detached process back to its original
1087 			 * parent.  Otherwise the debugee will be set
1088 			 * as an orphan of the debugger.
1089 			 */
1090 			p->p_flag &= ~(P_TRACED | P_WAITED);
1091 
1092 			/*
1093 			 * Reset the process parent.
1094 			 */
1095 			if (p->p_oppid != p->p_pptr->p_pid) {
1096 				PROC_LOCK(p->p_pptr);
1097 				sigqueue_take(p->p_ksi);
1098 				PROC_UNLOCK(p->p_pptr);
1099 
1100 				pp = proc_realparent(p);
1101 				proc_reparent(p, pp, false);
1102 				if (pp == initproc)
1103 					p->p_sigparent = SIGCHLD;
1104 				CTR3(KTR_PTRACE,
1105 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1106 				    p->p_pid, pp->p_pid, data);
1107 			} else {
1108 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1109 				    p->p_pid, data);
1110 			}
1111 
1112 			p->p_ptevents = 0;
1113 			FOREACH_THREAD_IN_PROC(p, td3) {
1114 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1115 					sigqueue_delete(&td3->td_sigqueue,
1116 					    SIGSTOP);
1117 				}
1118 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1119 				    TDB_SUSPEND);
1120 			}
1121 
1122 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1123 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1124 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1125 			}
1126 
1127 			/* should we send SIGCHLD? */
1128 			/* childproc_continued(p); */
1129 			break;
1130 		}
1131 
1132 		sx_xunlock(&proctree_lock);
1133 		proctree_locked = false;
1134 
1135 	sendsig:
1136 		MPASS(!proctree_locked);
1137 
1138 		/*
1139 		 * Clear the pending event for the thread that just
1140 		 * reported its event (p_xthread).  This may not be
1141 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1142 		 * the debugger is resuming a different thread.
1143 		 *
1144 		 * Deliver any pending signal via the reporting thread.
1145 		 */
1146 		MPASS(p->p_xthread != NULL);
1147 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1148 		p->p_xthread->td_xsig = data;
1149 		p->p_xthread = NULL;
1150 		p->p_xsig = data;
1151 
1152 		/*
1153 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1154 		 * always works immediately, even if another thread is
1155 		 * unsuspended first and attempts to handle a
1156 		 * different signal or if the POSIX.1b style signal
1157 		 * queue cannot accommodate any new signals.
1158 		 */
1159 		if (data == SIGKILL)
1160 			proc_wkilled(p);
1161 
1162 		/*
1163 		 * Unsuspend all threads.  To leave a thread
1164 		 * suspended, use PT_SUSPEND to suspend it before
1165 		 * continuing the process.
1166 		 */
1167 		PROC_SLOCK(p);
1168 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1169 		thread_unsuspend(p);
1170 		PROC_SUNLOCK(p);
1171 		itimer_proc_continue(p);
1172 		kqtimer_proc_continue(p);
1173 		break;
1174 
1175 	case PT_WRITE_I:
1176 	case PT_WRITE_D:
1177 		td2->td_dbgflags |= TDB_USERWR;
1178 		PROC_UNLOCK(p);
1179 		error = 0;
1180 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1181 		    sizeof(int)) != sizeof(int))
1182 			error = ENOMEM;
1183 		else
1184 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1185 			    p->p_pid, addr, data);
1186 		PROC_LOCK(p);
1187 		break;
1188 
1189 	case PT_READ_I:
1190 	case PT_READ_D:
1191 		PROC_UNLOCK(p);
1192 		error = tmp = 0;
1193 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1194 		    sizeof(int)) != sizeof(int))
1195 			error = ENOMEM;
1196 		else
1197 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1198 			    p->p_pid, addr, tmp);
1199 		td->td_retval[0] = tmp;
1200 		PROC_LOCK(p);
1201 		break;
1202 
1203 	case PT_IO:
1204 		piod = addr;
1205 		iov.iov_base = piod->piod_addr;
1206 		iov.iov_len = piod->piod_len;
1207 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1208 		uio.uio_resid = piod->piod_len;
1209 		uio.uio_iov = &iov;
1210 		uio.uio_iovcnt = 1;
1211 		uio.uio_segflg = UIO_USERSPACE;
1212 		uio.uio_td = td;
1213 		switch (piod->piod_op) {
1214 		case PIOD_READ_D:
1215 		case PIOD_READ_I:
1216 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1217 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1218 			uio.uio_rw = UIO_READ;
1219 			break;
1220 		case PIOD_WRITE_D:
1221 		case PIOD_WRITE_I:
1222 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1223 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1224 			td2->td_dbgflags |= TDB_USERWR;
1225 			uio.uio_rw = UIO_WRITE;
1226 			break;
1227 		default:
1228 			error = EINVAL;
1229 			goto out;
1230 		}
1231 		PROC_UNLOCK(p);
1232 		error = proc_rwmem(p, &uio);
1233 		piod->piod_len -= uio.uio_resid;
1234 		PROC_LOCK(p);
1235 		break;
1236 
1237 	case PT_KILL:
1238 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1239 		data = SIGKILL;
1240 		goto sendsig;	/* in PT_CONTINUE above */
1241 
1242 	case PT_SETREGS:
1243 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1244 		    p->p_pid);
1245 		td2->td_dbgflags |= TDB_USERWR;
1246 		error = PROC_WRITE(regs, td2, addr);
1247 		break;
1248 
1249 	case PT_GETREGS:
1250 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1251 		    p->p_pid);
1252 		error = PROC_READ(regs, td2, addr);
1253 		break;
1254 
1255 	case PT_SETFPREGS:
1256 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1257 		    p->p_pid);
1258 		td2->td_dbgflags |= TDB_USERWR;
1259 		error = PROC_WRITE(fpregs, td2, addr);
1260 		break;
1261 
1262 	case PT_GETFPREGS:
1263 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1264 		    p->p_pid);
1265 		error = PROC_READ(fpregs, td2, addr);
1266 		break;
1267 
1268 	case PT_SETDBREGS:
1269 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1270 		    p->p_pid);
1271 		td2->td_dbgflags |= TDB_USERWR;
1272 		error = PROC_WRITE(dbregs, td2, addr);
1273 		break;
1274 
1275 	case PT_GETDBREGS:
1276 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1277 		    p->p_pid);
1278 		error = PROC_READ(dbregs, td2, addr);
1279 		break;
1280 
1281 	case PT_LWPINFO:
1282 		if (data <= 0 || data > sizeof(*pl)) {
1283 			error = EINVAL;
1284 			break;
1285 		}
1286 		pl = addr;
1287 		bzero(pl, sizeof(*pl));
1288 		pl->pl_lwpid = td2->td_tid;
1289 		pl->pl_event = PL_EVENT_NONE;
1290 		pl->pl_flags = 0;
1291 		if (td2->td_dbgflags & TDB_XSIG) {
1292 			pl->pl_event = PL_EVENT_SIGNAL;
1293 			if (td2->td_si.si_signo != 0 &&
1294 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1295 			    + sizeof(pl->pl_siginfo)){
1296 				pl->pl_flags |= PL_FLAG_SI;
1297 				pl->pl_siginfo = td2->td_si;
1298 			}
1299 		}
1300 		if (td2->td_dbgflags & TDB_SCE)
1301 			pl->pl_flags |= PL_FLAG_SCE;
1302 		else if (td2->td_dbgflags & TDB_SCX)
1303 			pl->pl_flags |= PL_FLAG_SCX;
1304 		if (td2->td_dbgflags & TDB_EXEC)
1305 			pl->pl_flags |= PL_FLAG_EXEC;
1306 		if (td2->td_dbgflags & TDB_FORK) {
1307 			pl->pl_flags |= PL_FLAG_FORKED;
1308 			pl->pl_child_pid = td2->td_dbg_forked;
1309 			if (td2->td_dbgflags & TDB_VFORK)
1310 				pl->pl_flags |= PL_FLAG_VFORKED;
1311 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1312 		    TDB_VFORK)
1313 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1314 		if (td2->td_dbgflags & TDB_CHILD)
1315 			pl->pl_flags |= PL_FLAG_CHILD;
1316 		if (td2->td_dbgflags & TDB_BORN)
1317 			pl->pl_flags |= PL_FLAG_BORN;
1318 		if (td2->td_dbgflags & TDB_EXIT)
1319 			pl->pl_flags |= PL_FLAG_EXITED;
1320 		pl->pl_sigmask = td2->td_sigmask;
1321 		pl->pl_siglist = td2->td_siglist;
1322 		strcpy(pl->pl_tdname, td2->td_name);
1323 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1324 			pl->pl_syscall_code = td2->td_sa.code;
1325 			pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1326 		} else {
1327 			pl->pl_syscall_code = 0;
1328 			pl->pl_syscall_narg = 0;
1329 		}
1330 		CTR6(KTR_PTRACE,
1331     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1332 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1333 		    pl->pl_child_pid, pl->pl_syscall_code);
1334 		break;
1335 
1336 	case PT_GETNUMLWPS:
1337 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1338 		    p->p_numthreads);
1339 		td->td_retval[0] = p->p_numthreads;
1340 		break;
1341 
1342 	case PT_GETLWPLIST:
1343 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1344 		    p->p_pid, data, p->p_numthreads);
1345 		if (data <= 0) {
1346 			error = EINVAL;
1347 			break;
1348 		}
1349 		num = imin(p->p_numthreads, data);
1350 		PROC_UNLOCK(p);
1351 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1352 		tmp = 0;
1353 		PROC_LOCK(p);
1354 		FOREACH_THREAD_IN_PROC(p, td2) {
1355 			if (tmp >= num)
1356 				break;
1357 			buf[tmp++] = td2->td_tid;
1358 		}
1359 		PROC_UNLOCK(p);
1360 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1361 		free(buf, M_TEMP);
1362 		if (!error)
1363 			td->td_retval[0] = tmp;
1364 		PROC_LOCK(p);
1365 		break;
1366 
1367 	case PT_VM_TIMESTAMP:
1368 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1369 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1370 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1371 		break;
1372 
1373 	case PT_VM_ENTRY:
1374 		PROC_UNLOCK(p);
1375 		error = ptrace_vm_entry(td, p, addr);
1376 		PROC_LOCK(p);
1377 		break;
1378 
1379 	case PT_COREDUMP:
1380 		pc = addr;
1381 		CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1382 		    p->p_pid, pc->pc_fd);
1383 
1384 		if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1385 			error = EINVAL;
1386 			break;
1387 		}
1388 		PROC_UNLOCK(p);
1389 
1390 		tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1391 		fp = NULL;
1392 		error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1393 		if (error != 0)
1394 			goto coredump_cleanup_nofp;
1395 		if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1396 			error = EPIPE;
1397 			goto coredump_cleanup;
1398 		}
1399 
1400 		PROC_LOCK(p);
1401 		error = proc_can_ptrace(td, p);
1402 		if (error != 0)
1403 			goto coredump_cleanup_locked;
1404 
1405 		td2 = ptrace_sel_coredump_thread(p);
1406 		if (td2 == NULL) {
1407 			error = EBUSY;
1408 			goto coredump_cleanup_locked;
1409 		}
1410 		KASSERT((td2->td_dbgflags & TDB_COREDUMPRQ) == 0,
1411 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1412 
1413 		tcq->tc_vp = fp->f_vnode;
1414 		tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1415 		tcq->tc_flags = SVC_PT_COREDUMP;
1416 		if ((pc->pc_flags & PC_COMPRESS) == 0)
1417 			tcq->tc_flags |= SVC_NOCOMPRESS;
1418 		if ((pc->pc_flags & PC_ALL) != 0)
1419 			tcq->tc_flags |= SVC_ALL;
1420 		td2->td_coredump = tcq;
1421 		td2->td_dbgflags |= TDB_COREDUMPRQ;
1422 		thread_run_flash(td2);
1423 		while ((td2->td_dbgflags & TDB_COREDUMPRQ) != 0)
1424 			msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1425 		error = tcq->tc_error;
1426 coredump_cleanup_locked:
1427 		PROC_UNLOCK(p);
1428 coredump_cleanup:
1429 		fdrop(fp, td);
1430 coredump_cleanup_nofp:
1431 		free(tcq, M_TEMP);
1432 		PROC_LOCK(p);
1433 		break;
1434 
1435 	default:
1436 #ifdef __HAVE_PTRACE_MACHDEP
1437 		if (req >= PT_FIRSTMACH) {
1438 			PROC_UNLOCK(p);
1439 			error = cpu_ptrace(td2, req, addr, data);
1440 			PROC_LOCK(p);
1441 		} else
1442 #endif
1443 			/* Unknown request. */
1444 			error = EINVAL;
1445 		break;
1446 	}
1447 out:
1448 	/* Drop our hold on this process now that the request has completed. */
1449 	_PRELE(p);
1450 fail:
1451 	if (p2_req_set) {
1452 		if ((p->p_flag2 & P2_PTRACEREQ) != 0)
1453 			wakeup(&p->p_flag2);
1454 		p->p_flag2 &= ~P2_PTRACEREQ;
1455 	}
1456 	PROC_UNLOCK(p);
1457 	if (proctree_locked)
1458 		sx_xunlock(&proctree_lock);
1459 	return (error);
1460 }
1461 #undef PROC_READ
1462 #undef PROC_WRITE
1463