xref: /freebsd/sys/kern/sys_process.c (revision 83958173eb7d3f9d402e6dc81e66d179a808dd63)
1 /*-
2  * SPDX-License-Identifier: BSD-4-Clause
3  *
4  * Copyright (c) 1994, Sean Eric Fagan
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by Sean Eric Fagan.
18  * 4. The name of the author may not be used to endorse or promote products
19  *    derived from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/ktr.h>
40 #include <sys/limits.h>
41 #include <sys/lock.h>
42 #include <sys/mutex.h>
43 #include <sys/reg.h>
44 #include <sys/syscallsubr.h>
45 #include <sys/sysent.h>
46 #include <sys/sysproto.h>
47 #include <sys/priv.h>
48 #include <sys/proc.h>
49 #include <sys/vnode.h>
50 #include <sys/ptrace.h>
51 #include <sys/rwlock.h>
52 #include <sys/sx.h>
53 #include <sys/malloc.h>
54 #include <sys/signalvar.h>
55 #include <sys/caprights.h>
56 #include <sys/filedesc.h>
57 
58 #include <security/audit/audit.h>
59 
60 #include <vm/vm.h>
61 #include <vm/pmap.h>
62 #include <vm/vm_extern.h>
63 #include <vm/vm_map.h>
64 #include <vm/vm_kern.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_param.h>
68 
69 #ifdef COMPAT_FREEBSD32
70 #include <sys/procfs.h>
71 #endif
72 
73 /* Assert it's safe to unlock a process, e.g. to allocate working memory */
74 #define	PROC_ASSERT_TRACEREQ(p)	MPASS(((p)->p_flag2 & P2_PTRACEREQ) != 0)
75 
76 /*
77  * Functions implemented using PROC_ACTION():
78  *
79  * proc_read_regs(proc, regs)
80  *	Get the current user-visible register set from the process
81  *	and copy it into the regs structure (<machine/reg.h>).
82  *	The process is stopped at the time read_regs is called.
83  *
84  * proc_write_regs(proc, regs)
85  *	Update the current register set from the passed in regs
86  *	structure.  Take care to avoid clobbering special CPU
87  *	registers or privileged bits in the PSL.
88  *	Depending on the architecture this may have fix-up work to do,
89  *	especially if the IAR or PCW are modified.
90  *	The process is stopped at the time write_regs is called.
91  *
92  * proc_read_fpregs, proc_write_fpregs
93  *	deal with the floating point register set, otherwise as above.
94  *
95  * proc_read_dbregs, proc_write_dbregs
96  *	deal with the processor debug register set, otherwise as above.
97  *
98  * proc_sstep(proc)
99  *	Arrange for the process to trap after executing a single instruction.
100  */
101 
102 #define	PROC_ACTION(action) do {					\
103 	int error;							\
104 									\
105 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
106 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
107 		error = EIO;						\
108 	else								\
109 		error = (action);					\
110 	return (error);							\
111 } while (0)
112 
113 int
114 proc_read_regs(struct thread *td, struct reg *regs)
115 {
116 
117 	PROC_ACTION(fill_regs(td, regs));
118 }
119 
120 int
121 proc_write_regs(struct thread *td, struct reg *regs)
122 {
123 
124 	PROC_ACTION(set_regs(td, regs));
125 }
126 
127 int
128 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
129 {
130 
131 	PROC_ACTION(fill_dbregs(td, dbregs));
132 }
133 
134 int
135 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
136 {
137 
138 	PROC_ACTION(set_dbregs(td, dbregs));
139 }
140 
141 /*
142  * Ptrace doesn't support fpregs at all, and there are no security holes
143  * or translations for fpregs, so we can just copy them.
144  */
145 int
146 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
147 {
148 
149 	PROC_ACTION(fill_fpregs(td, fpregs));
150 }
151 
152 int
153 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
154 {
155 
156 	PROC_ACTION(set_fpregs(td, fpregs));
157 }
158 
159 static struct regset *
160 proc_find_regset(struct thread *td, int note)
161 {
162 	struct regset **regsetp, **regset_end, *regset;
163 	struct sysentvec *sv;
164 
165 	sv = td->td_proc->p_sysent;
166 	regsetp = sv->sv_regset_begin;
167 	if (regsetp == NULL)
168 		return (NULL);
169 	regset_end = sv->sv_regset_end;
170 	MPASS(regset_end != NULL);
171 	for (; regsetp < regset_end; regsetp++) {
172 		regset = *regsetp;
173 		if (regset->note != note)
174 			continue;
175 
176 		return (regset);
177 	}
178 
179 	return (NULL);
180 }
181 
182 static int
183 proc_read_regset(struct thread *td, int note, struct iovec *iov)
184 {
185 	struct regset *regset;
186 	struct proc *p;
187 	void *buf;
188 	size_t size;
189 	int error;
190 
191 	regset = proc_find_regset(td, note);
192 	if (regset == NULL)
193 		return (EINVAL);
194 
195 	if (iov->iov_base == NULL) {
196 		iov->iov_len = regset->size;
197 		if (iov->iov_len == 0)
198 			return (EINVAL);
199 
200 		return (0);
201 	}
202 
203 	/* The length is wrong, return an error */
204 	if (iov->iov_len != regset->size)
205 		return (EINVAL);
206 
207 	if (regset->get == NULL)
208 		return (EINVAL);
209 
210 	error = 0;
211 	size = regset->size;
212 	p = td->td_proc;
213 
214 	/* Drop the proc lock while allocating the temp buffer */
215 	PROC_ASSERT_TRACEREQ(p);
216 	PROC_UNLOCK(p);
217 	buf = malloc(size, M_TEMP, M_WAITOK);
218 	PROC_LOCK(p);
219 
220 	if (!regset->get(regset, td, buf, &size)) {
221 		error = EINVAL;
222 	} else {
223 		KASSERT(size == regset->size,
224 		    ("%s: Getter function changed the size", __func__));
225 
226 		iov->iov_len = size;
227 		PROC_UNLOCK(p);
228 		error = copyout(buf, iov->iov_base, size);
229 		PROC_LOCK(p);
230 	}
231 
232 	free(buf, M_TEMP);
233 
234 	return (error);
235 }
236 
237 static int
238 proc_write_regset(struct thread *td, int note, struct iovec *iov)
239 {
240 	struct regset *regset;
241 	struct proc *p;
242 	void *buf;
243 	size_t size;
244 	int error;
245 
246 	regset = proc_find_regset(td, note);
247 	if (regset == NULL)
248 		return (EINVAL);
249 
250 	/* The length is wrong, return an error */
251 	if (iov->iov_len != regset->size)
252 		return (EINVAL);
253 
254 	if (regset->set == NULL)
255 		return (EINVAL);
256 
257 	size = regset->size;
258 	p = td->td_proc;
259 
260 	/* Drop the proc lock while allocating the temp buffer */
261 	PROC_ASSERT_TRACEREQ(p);
262 	PROC_UNLOCK(p);
263 	buf = malloc(size, M_TEMP, M_WAITOK);
264 	error = copyin(iov->iov_base, buf, size);
265 	PROC_LOCK(p);
266 
267 	if (error == 0) {
268 		if (!regset->set(regset, td, buf, size)) {
269 			error = EINVAL;
270 		}
271 	}
272 
273 	free(buf, M_TEMP);
274 
275 	return (error);
276 }
277 
278 #ifdef COMPAT_FREEBSD32
279 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
280 int
281 proc_read_regs32(struct thread *td, struct reg32 *regs32)
282 {
283 
284 	PROC_ACTION(fill_regs32(td, regs32));
285 }
286 
287 int
288 proc_write_regs32(struct thread *td, struct reg32 *regs32)
289 {
290 
291 	PROC_ACTION(set_regs32(td, regs32));
292 }
293 
294 int
295 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
296 {
297 
298 	PROC_ACTION(fill_dbregs32(td, dbregs32));
299 }
300 
301 int
302 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
303 {
304 
305 	PROC_ACTION(set_dbregs32(td, dbregs32));
306 }
307 
308 int
309 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
310 {
311 
312 	PROC_ACTION(fill_fpregs32(td, fpregs32));
313 }
314 
315 int
316 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
317 {
318 
319 	PROC_ACTION(set_fpregs32(td, fpregs32));
320 }
321 #endif
322 
323 int
324 proc_sstep(struct thread *td)
325 {
326 
327 	PROC_ACTION(ptrace_single_step(td));
328 }
329 
330 int
331 proc_rwmem(struct proc *p, struct uio *uio)
332 {
333 	vm_map_t map;
334 	vm_offset_t pageno;		/* page number */
335 	vm_prot_t reqprot;
336 	int error, fault_flags, page_offset, writing;
337 
338 	/*
339 	 * Make sure that the process' vmspace remains live.
340 	 */
341 	if (p != curproc)
342 		PROC_ASSERT_HELD(p);
343 	KASSERT((p->p_flag & P_WEXIT) == 0,
344 	    ("%s: process %p is exiting", __func__, p));
345 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
346 
347 	/*
348 	 * The map we want...
349 	 */
350 	map = &p->p_vmspace->vm_map;
351 
352 	/*
353 	 * If we are writing, then we request vm_fault() to create a private
354 	 * copy of each page.  Since these copies will not be writeable by the
355 	 * process, we must explicity request that they be dirtied.
356 	 */
357 	writing = uio->uio_rw == UIO_WRITE;
358 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
359 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
360 
361 	/*
362 	 * Only map in one page at a time.  We don't have to, but it
363 	 * makes things easier.  This way is trivial - right?
364 	 */
365 	do {
366 		vm_offset_t uva;
367 		u_int len;
368 		vm_page_t m;
369 
370 		uva = (vm_offset_t)uio->uio_offset;
371 
372 		/*
373 		 * Get the page number of this segment.
374 		 */
375 		pageno = trunc_page(uva);
376 		page_offset = uva - pageno;
377 
378 		/*
379 		 * How many bytes to copy
380 		 */
381 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
382 
383 		/*
384 		 * Fault and hold the page on behalf of the process.
385 		 */
386 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
387 		if (error != KERN_SUCCESS) {
388 			if (error == KERN_RESOURCE_SHORTAGE)
389 				error = ENOMEM;
390 			else
391 				error = EFAULT;
392 			break;
393 		}
394 
395 		/*
396 		 * Now do the i/o move.
397 		 */
398 		error = uiomove_fromphys(&m, page_offset, len, uio);
399 
400 		/* Make the I-cache coherent for breakpoints. */
401 		if (writing && error == 0) {
402 			vm_map_lock_read(map);
403 			if (vm_map_check_protection(map, pageno, pageno +
404 			    PAGE_SIZE, VM_PROT_EXECUTE))
405 				vm_sync_icache(map, uva, len);
406 			vm_map_unlock_read(map);
407 		}
408 
409 		/*
410 		 * Release the page.
411 		 */
412 		vm_page_unwire(m, PQ_ACTIVE);
413 
414 	} while (error == 0 && uio->uio_resid > 0);
415 
416 	return (error);
417 }
418 
419 static ssize_t
420 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
421     size_t len, enum uio_rw rw)
422 {
423 	struct iovec iov;
424 	struct uio uio;
425 	ssize_t slen;
426 
427 	MPASS(len < SSIZE_MAX);
428 	slen = (ssize_t)len;
429 
430 	iov.iov_base = (caddr_t)buf;
431 	iov.iov_len = len;
432 	uio.uio_iov = &iov;
433 	uio.uio_iovcnt = 1;
434 	uio.uio_offset = va;
435 	uio.uio_resid = slen;
436 	uio.uio_segflg = UIO_SYSSPACE;
437 	uio.uio_rw = rw;
438 	uio.uio_td = td;
439 	proc_rwmem(p, &uio);
440 	if (uio.uio_resid == slen)
441 		return (-1);
442 	return (slen - uio.uio_resid);
443 }
444 
445 ssize_t
446 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
447     size_t len)
448 {
449 
450 	return (proc_iop(td, p, va, buf, len, UIO_READ));
451 }
452 
453 ssize_t
454 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
455     size_t len)
456 {
457 
458 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
459 }
460 
461 static int
462 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
463 {
464 	struct vattr vattr;
465 	vm_map_t map;
466 	vm_map_entry_t entry;
467 	vm_object_t obj, tobj, lobj;
468 	struct vmspace *vm;
469 	struct vnode *vp;
470 	char *freepath, *fullpath;
471 	u_int pathlen;
472 	int error, index;
473 
474 	error = 0;
475 	obj = NULL;
476 
477 	vm = vmspace_acquire_ref(p);
478 	map = &vm->vm_map;
479 	vm_map_lock_read(map);
480 
481 	do {
482 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
483 		    ("Submap in map header"));
484 		index = 0;
485 		VM_MAP_ENTRY_FOREACH(entry, map) {
486 			if (index >= pve->pve_entry &&
487 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
488 				break;
489 			index++;
490 		}
491 		if (index < pve->pve_entry) {
492 			error = EINVAL;
493 			break;
494 		}
495 		if (entry == &map->header) {
496 			error = ENOENT;
497 			break;
498 		}
499 
500 		/* We got an entry. */
501 		pve->pve_entry = index + 1;
502 		pve->pve_timestamp = map->timestamp;
503 		pve->pve_start = entry->start;
504 		pve->pve_end = entry->end - 1;
505 		pve->pve_offset = entry->offset;
506 		pve->pve_prot = entry->protection;
507 
508 		/* Backing object's path needed? */
509 		if (pve->pve_pathlen == 0)
510 			break;
511 
512 		pathlen = pve->pve_pathlen;
513 		pve->pve_pathlen = 0;
514 
515 		obj = entry->object.vm_object;
516 		if (obj != NULL)
517 			VM_OBJECT_RLOCK(obj);
518 	} while (0);
519 
520 	vm_map_unlock_read(map);
521 
522 	pve->pve_fsid = VNOVAL;
523 	pve->pve_fileid = VNOVAL;
524 
525 	if (error == 0 && obj != NULL) {
526 		lobj = obj;
527 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
528 			if (tobj != obj)
529 				VM_OBJECT_RLOCK(tobj);
530 			if (lobj != obj)
531 				VM_OBJECT_RUNLOCK(lobj);
532 			lobj = tobj;
533 			pve->pve_offset += tobj->backing_object_offset;
534 		}
535 		vp = vm_object_vnode(lobj);
536 		if (vp != NULL)
537 			vref(vp);
538 		if (lobj != obj)
539 			VM_OBJECT_RUNLOCK(lobj);
540 		VM_OBJECT_RUNLOCK(obj);
541 
542 		if (vp != NULL) {
543 			freepath = NULL;
544 			fullpath = NULL;
545 			vn_fullpath(vp, &fullpath, &freepath);
546 			vn_lock(vp, LK_SHARED | LK_RETRY);
547 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
548 				pve->pve_fileid = vattr.va_fileid;
549 				pve->pve_fsid = vattr.va_fsid;
550 			}
551 			vput(vp);
552 
553 			if (fullpath != NULL) {
554 				pve->pve_pathlen = strlen(fullpath) + 1;
555 				if (pve->pve_pathlen <= pathlen) {
556 					error = copyout(fullpath, pve->pve_path,
557 					    pve->pve_pathlen);
558 				} else
559 					error = ENAMETOOLONG;
560 			}
561 			if (freepath != NULL)
562 				free(freepath, M_TEMP);
563 		}
564 	}
565 	vmspace_free(vm);
566 	if (error == 0)
567 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
568 		    p->p_pid, pve->pve_entry, pve->pve_start);
569 
570 	return (error);
571 }
572 
573 /*
574  * Process debugging system call.
575  */
576 #ifndef _SYS_SYSPROTO_H_
577 struct ptrace_args {
578 	int	req;
579 	pid_t	pid;
580 	caddr_t	addr;
581 	int	data;
582 };
583 #endif
584 
585 int
586 sys_ptrace(struct thread *td, struct ptrace_args *uap)
587 {
588 	/*
589 	 * XXX this obfuscation is to reduce stack usage, but the register
590 	 * structs may be too large to put on the stack anyway.
591 	 */
592 	union {
593 		struct ptrace_io_desc piod;
594 		struct ptrace_lwpinfo pl;
595 		struct ptrace_vm_entry pve;
596 		struct ptrace_coredump pc;
597 		struct dbreg dbreg;
598 		struct fpreg fpreg;
599 		struct reg reg;
600 		struct iovec vec;
601 		char args[sizeof(td->td_sa.args)];
602 		struct ptrace_sc_ret psr;
603 		int ptevents;
604 	} r;
605 	void *addr;
606 	int error;
607 
608 	if (!allow_ptrace)
609 		return (ENOSYS);
610 	error = 0;
611 
612 	AUDIT_ARG_PID(uap->pid);
613 	AUDIT_ARG_CMD(uap->req);
614 	AUDIT_ARG_VALUE(uap->data);
615 	addr = &r;
616 	switch (uap->req) {
617 	case PT_GET_EVENT_MASK:
618 	case PT_LWPINFO:
619 	case PT_GET_SC_ARGS:
620 	case PT_GET_SC_RET:
621 		break;
622 	case PT_GETREGS:
623 		bzero(&r.reg, sizeof(r.reg));
624 		break;
625 	case PT_GETFPREGS:
626 		bzero(&r.fpreg, sizeof(r.fpreg));
627 		break;
628 	case PT_GETDBREGS:
629 		bzero(&r.dbreg, sizeof(r.dbreg));
630 		break;
631 	case PT_GETREGSET:
632 	case PT_SETREGSET:
633 		error = copyin(uap->addr, &r.vec, sizeof(r.vec));
634 		break;
635 	case PT_SETREGS:
636 		error = copyin(uap->addr, &r.reg, sizeof(r.reg));
637 		break;
638 	case PT_SETFPREGS:
639 		error = copyin(uap->addr, &r.fpreg, sizeof(r.fpreg));
640 		break;
641 	case PT_SETDBREGS:
642 		error = copyin(uap->addr, &r.dbreg, sizeof(r.dbreg));
643 		break;
644 	case PT_SET_EVENT_MASK:
645 		if (uap->data != sizeof(r.ptevents))
646 			error = EINVAL;
647 		else
648 			error = copyin(uap->addr, &r.ptevents, uap->data);
649 		break;
650 	case PT_IO:
651 		error = copyin(uap->addr, &r.piod, sizeof(r.piod));
652 		break;
653 	case PT_VM_ENTRY:
654 		error = copyin(uap->addr, &r.pve, sizeof(r.pve));
655 		break;
656 	case PT_COREDUMP:
657 		if (uap->data != sizeof(r.pc))
658 			error = EINVAL;
659 		else
660 			error = copyin(uap->addr, &r.pc, uap->data);
661 		break;
662 	default:
663 		addr = uap->addr;
664 		break;
665 	}
666 	if (error)
667 		return (error);
668 
669 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
670 	if (error)
671 		return (error);
672 
673 	switch (uap->req) {
674 	case PT_VM_ENTRY:
675 		error = copyout(&r.pve, uap->addr, sizeof(r.pve));
676 		break;
677 	case PT_IO:
678 		error = copyout(&r.piod, uap->addr, sizeof(r.piod));
679 		break;
680 	case PT_GETREGS:
681 		error = copyout(&r.reg, uap->addr, sizeof(r.reg));
682 		break;
683 	case PT_GETFPREGS:
684 		error = copyout(&r.fpreg, uap->addr, sizeof(r.fpreg));
685 		break;
686 	case PT_GETDBREGS:
687 		error = copyout(&r.dbreg, uap->addr, sizeof(r.dbreg));
688 		break;
689 	case PT_GETREGSET:
690 		error = copyout(&r.vec, uap->addr, sizeof(r.vec));
691 		break;
692 	case PT_GET_EVENT_MASK:
693 		/* NB: The size in uap->data is validated in kern_ptrace(). */
694 		error = copyout(&r.ptevents, uap->addr, uap->data);
695 		break;
696 	case PT_LWPINFO:
697 		/* NB: The size in uap->data is validated in kern_ptrace(). */
698 		error = copyout(&r.pl, uap->addr, uap->data);
699 		break;
700 	case PT_GET_SC_ARGS:
701 		error = copyout(r.args, uap->addr, MIN(uap->data,
702 		    sizeof(r.args)));
703 		break;
704 	case PT_GET_SC_RET:
705 		error = copyout(&r.psr, uap->addr, MIN(uap->data,
706 		    sizeof(r.psr)));
707 		break;
708 	}
709 
710 	return (error);
711 }
712 
713 #ifdef COMPAT_FREEBSD32
714 /*
715  *   PROC_READ(regs, td2, addr);
716  * becomes either:
717  *   proc_read_regs(td2, addr);
718  * or
719  *   proc_read_regs32(td2, addr);
720  * .. except this is done at runtime.  There is an additional
721  * complication in that PROC_WRITE disallows 32 bit consumers
722  * from writing to 64 bit address space targets.
723  */
724 #define	PROC_READ(w, t, a)	wrap32 ? \
725 	proc_read_ ## w ## 32(t, a) : \
726 	proc_read_ ## w (t, a)
727 #define	PROC_WRITE(w, t, a)	wrap32 ? \
728 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
729 	proc_write_ ## w (t, a)
730 #else
731 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
732 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
733 #endif
734 
735 void
736 proc_set_traced(struct proc *p, bool stop)
737 {
738 
739 	sx_assert(&proctree_lock, SX_XLOCKED);
740 	PROC_LOCK_ASSERT(p, MA_OWNED);
741 	p->p_flag |= P_TRACED;
742 	if (stop)
743 		p->p_flag2 |= P2_PTRACE_FSTP;
744 	p->p_ptevents = PTRACE_DEFAULT;
745 }
746 
747 void
748 ptrace_unsuspend(struct proc *p)
749 {
750 	PROC_LOCK_ASSERT(p, MA_OWNED);
751 
752 	PROC_SLOCK(p);
753 	p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
754 	thread_unsuspend(p);
755 	PROC_SUNLOCK(p);
756 	itimer_proc_continue(p);
757 	kqtimer_proc_continue(p);
758 }
759 
760 static int
761 proc_can_ptrace(struct thread *td, struct proc *p)
762 {
763 	int error;
764 
765 	PROC_LOCK_ASSERT(p, MA_OWNED);
766 
767 	if ((p->p_flag & P_WEXIT) != 0)
768 		return (ESRCH);
769 
770 	if ((error = p_cansee(td, p)) != 0)
771 		return (error);
772 	if ((error = p_candebug(td, p)) != 0)
773 		return (error);
774 
775 	/* not being traced... */
776 	if ((p->p_flag & P_TRACED) == 0)
777 		return (EPERM);
778 
779 	/* not being traced by YOU */
780 	if (p->p_pptr != td->td_proc)
781 		return (EBUSY);
782 
783 	/* not currently stopped */
784 	if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
785 	    p->p_suspcount != p->p_numthreads  ||
786 	    (p->p_flag & P_WAITED) == 0)
787 		return (EBUSY);
788 
789 	return (0);
790 }
791 
792 static struct thread *
793 ptrace_sel_coredump_thread(struct proc *p)
794 {
795 	struct thread *td2;
796 
797 	PROC_LOCK_ASSERT(p, MA_OWNED);
798 	MPASS((p->p_flag & P_STOPPED_TRACE) != 0);
799 
800 	FOREACH_THREAD_IN_PROC(p, td2) {
801 		if ((td2->td_dbgflags & TDB_SSWITCH) != 0)
802 			return (td2);
803 	}
804 	return (NULL);
805 }
806 
807 int
808 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
809 {
810 	struct iovec iov;
811 	struct uio uio;
812 	struct proc *curp, *p, *pp;
813 	struct thread *td2 = NULL, *td3;
814 	struct ptrace_io_desc *piod = NULL;
815 	struct ptrace_lwpinfo *pl;
816 	struct ptrace_sc_ret *psr;
817 	struct file *fp;
818 	struct ptrace_coredump *pc;
819 	struct thr_coredump_req *tcq;
820 	int error, num, tmp;
821 	lwpid_t tid = 0, *buf;
822 #ifdef COMPAT_FREEBSD32
823 	int wrap32 = 0, safe = 0;
824 #endif
825 	bool proctree_locked, p2_req_set;
826 
827 	curp = td->td_proc;
828 	proctree_locked = false;
829 	p2_req_set = false;
830 
831 	/* Lock proctree before locking the process. */
832 	switch (req) {
833 	case PT_TRACE_ME:
834 	case PT_ATTACH:
835 	case PT_STEP:
836 	case PT_CONTINUE:
837 	case PT_TO_SCE:
838 	case PT_TO_SCX:
839 	case PT_SYSCALL:
840 	case PT_FOLLOW_FORK:
841 	case PT_LWP_EVENTS:
842 	case PT_GET_EVENT_MASK:
843 	case PT_SET_EVENT_MASK:
844 	case PT_DETACH:
845 	case PT_GET_SC_ARGS:
846 		sx_xlock(&proctree_lock);
847 		proctree_locked = true;
848 		break;
849 	default:
850 		break;
851 	}
852 
853 	if (req == PT_TRACE_ME) {
854 		p = td->td_proc;
855 		PROC_LOCK(p);
856 	} else {
857 		if (pid <= PID_MAX) {
858 			if ((p = pfind(pid)) == NULL) {
859 				if (proctree_locked)
860 					sx_xunlock(&proctree_lock);
861 				return (ESRCH);
862 			}
863 		} else {
864 			td2 = tdfind(pid, -1);
865 			if (td2 == NULL) {
866 				if (proctree_locked)
867 					sx_xunlock(&proctree_lock);
868 				return (ESRCH);
869 			}
870 			p = td2->td_proc;
871 			tid = pid;
872 			pid = p->p_pid;
873 		}
874 	}
875 	AUDIT_ARG_PROCESS(p);
876 
877 	if ((p->p_flag & P_WEXIT) != 0) {
878 		error = ESRCH;
879 		goto fail;
880 	}
881 	if ((error = p_cansee(td, p)) != 0)
882 		goto fail;
883 
884 	if ((error = p_candebug(td, p)) != 0)
885 		goto fail;
886 
887 	/*
888 	 * System processes can't be debugged.
889 	 */
890 	if ((p->p_flag & P_SYSTEM) != 0) {
891 		error = EINVAL;
892 		goto fail;
893 	}
894 
895 	if (tid == 0) {
896 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
897 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
898 			td2 = p->p_xthread;
899 		} else {
900 			td2 = FIRST_THREAD_IN_PROC(p);
901 		}
902 		tid = td2->td_tid;
903 	}
904 
905 #ifdef COMPAT_FREEBSD32
906 	/*
907 	 * Test if we're a 32 bit client and what the target is.
908 	 * Set the wrap controls accordingly.
909 	 */
910 	if (SV_CURPROC_FLAG(SV_ILP32)) {
911 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
912 			safe = 1;
913 		wrap32 = 1;
914 	}
915 #endif
916 	/*
917 	 * Permissions check
918 	 */
919 	switch (req) {
920 	case PT_TRACE_ME:
921 		/*
922 		 * Always legal, when there is a parent process which
923 		 * could trace us.  Otherwise, reject.
924 		 */
925 		if ((p->p_flag & P_TRACED) != 0) {
926 			error = EBUSY;
927 			goto fail;
928 		}
929 		if (p->p_pptr == initproc) {
930 			error = EPERM;
931 			goto fail;
932 		}
933 		break;
934 
935 	case PT_ATTACH:
936 		/* Self */
937 		if (p == td->td_proc) {
938 			error = EINVAL;
939 			goto fail;
940 		}
941 
942 		/* Already traced */
943 		if (p->p_flag & P_TRACED) {
944 			error = EBUSY;
945 			goto fail;
946 		}
947 
948 		/* Can't trace an ancestor if you're being traced. */
949 		if (curp->p_flag & P_TRACED) {
950 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
951 				if (pp == p) {
952 					error = EINVAL;
953 					goto fail;
954 				}
955 			}
956 		}
957 
958 		/* OK */
959 		break;
960 
961 	case PT_CLEARSTEP:
962 		/* Allow thread to clear single step for itself */
963 		if (td->td_tid == tid)
964 			break;
965 
966 		/* FALLTHROUGH */
967 	default:
968 		/*
969 		 * Check for ptrace eligibility before waiting for
970 		 * holds to drain.
971 		 */
972 		error = proc_can_ptrace(td, p);
973 		if (error != 0)
974 			goto fail;
975 
976 		/*
977 		 * Block parallel ptrace requests.  Most important, do
978 		 * not allow other thread in debugger to continue the
979 		 * debuggee until coredump finished.
980 		 */
981 		while ((p->p_flag2 & P2_PTRACEREQ) != 0) {
982 			if (proctree_locked)
983 				sx_xunlock(&proctree_lock);
984 			error = msleep(&p->p_flag2, &p->p_mtx, PPAUSE | PCATCH |
985 			    (proctree_locked ? PDROP : 0), "pptrace", 0);
986 			if (proctree_locked) {
987 				sx_xlock(&proctree_lock);
988 				PROC_LOCK(p);
989 			}
990 			if (error == 0 && td2->td_proc != p)
991 				error = ESRCH;
992 			if (error == 0)
993 				error = proc_can_ptrace(td, p);
994 			if (error != 0)
995 				goto fail;
996 		}
997 
998 		/* Ok */
999 		break;
1000 	}
1001 
1002 	/*
1003 	 * Keep this process around and request parallel ptrace()
1004 	 * request to wait until we finish this request.
1005 	 */
1006 	MPASS((p->p_flag2 & P2_PTRACEREQ) == 0);
1007 	p->p_flag2 |= P2_PTRACEREQ;
1008 	p2_req_set = true;
1009 	_PHOLD(p);
1010 
1011 	/*
1012 	 * Actually do the requests
1013 	 */
1014 
1015 	td->td_retval[0] = 0;
1016 
1017 	switch (req) {
1018 	case PT_TRACE_ME:
1019 		/* set my trace flag and "owner" so it can read/write me */
1020 		proc_set_traced(p, false);
1021 		if (p->p_flag & P_PPWAIT)
1022 			p->p_flag |= P_PPTRACE;
1023 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
1024 		break;
1025 
1026 	case PT_ATTACH:
1027 		/* security check done above */
1028 		/*
1029 		 * It would be nice if the tracing relationship was separate
1030 		 * from the parent relationship but that would require
1031 		 * another set of links in the proc struct or for "wait"
1032 		 * to scan the entire proc table.  To make life easier,
1033 		 * we just re-parent the process we're trying to trace.
1034 		 * The old parent is remembered so we can put things back
1035 		 * on a "detach".
1036 		 */
1037 		proc_set_traced(p, true);
1038 		proc_reparent(p, td->td_proc, false);
1039 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
1040 		    p->p_oppid);
1041 
1042 		sx_xunlock(&proctree_lock);
1043 		proctree_locked = false;
1044 		MPASS(p->p_xthread == NULL);
1045 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
1046 
1047 		/*
1048 		 * If already stopped due to a stop signal, clear the
1049 		 * existing stop before triggering a traced SIGSTOP.
1050 		 */
1051 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
1052 			PROC_SLOCK(p);
1053 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
1054 			thread_unsuspend(p);
1055 			PROC_SUNLOCK(p);
1056 		}
1057 
1058 		kern_psignal(p, SIGSTOP);
1059 		break;
1060 
1061 	case PT_CLEARSTEP:
1062 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
1063 		    p->p_pid);
1064 		error = ptrace_clear_single_step(td2);
1065 		break;
1066 
1067 	case PT_SETSTEP:
1068 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
1069 		    p->p_pid);
1070 		error = ptrace_single_step(td2);
1071 		break;
1072 
1073 	case PT_SUSPEND:
1074 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
1075 		    p->p_pid);
1076 		td2->td_dbgflags |= TDB_SUSPEND;
1077 		thread_lock(td2);
1078 		td2->td_flags |= TDF_NEEDSUSPCHK;
1079 		thread_unlock(td2);
1080 		break;
1081 
1082 	case PT_RESUME:
1083 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
1084 		    p->p_pid);
1085 		td2->td_dbgflags &= ~TDB_SUSPEND;
1086 		break;
1087 
1088 	case PT_FOLLOW_FORK:
1089 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
1090 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
1091 		    data ? "enabled" : "disabled");
1092 		if (data)
1093 			p->p_ptevents |= PTRACE_FORK;
1094 		else
1095 			p->p_ptevents &= ~PTRACE_FORK;
1096 		break;
1097 
1098 	case PT_LWP_EVENTS:
1099 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
1100 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
1101 		    data ? "enabled" : "disabled");
1102 		if (data)
1103 			p->p_ptevents |= PTRACE_LWP;
1104 		else
1105 			p->p_ptevents &= ~PTRACE_LWP;
1106 		break;
1107 
1108 	case PT_GET_EVENT_MASK:
1109 		if (data != sizeof(p->p_ptevents)) {
1110 			error = EINVAL;
1111 			break;
1112 		}
1113 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1114 		    p->p_ptevents);
1115 		*(int *)addr = p->p_ptevents;
1116 		break;
1117 
1118 	case PT_SET_EVENT_MASK:
1119 		if (data != sizeof(p->p_ptevents)) {
1120 			error = EINVAL;
1121 			break;
1122 		}
1123 		tmp = *(int *)addr;
1124 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1125 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1126 			error = EINVAL;
1127 			break;
1128 		}
1129 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1130 		    p->p_pid, p->p_ptevents, tmp);
1131 		p->p_ptevents = tmp;
1132 		break;
1133 
1134 	case PT_GET_SC_ARGS:
1135 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1136 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1137 #ifdef COMPAT_FREEBSD32
1138 		    || (wrap32 && !safe)
1139 #endif
1140 		    ) {
1141 			error = EINVAL;
1142 			break;
1143 		}
1144 		bzero(addr, sizeof(td2->td_sa.args));
1145 		/* See the explanation in linux_ptrace_get_syscall_info(). */
1146 		bcopy(td2->td_sa.args, addr, SV_PROC_ABI(td->td_proc) ==
1147 		    SV_ABI_LINUX ? sizeof(td2->td_sa.args) :
1148 		    td2->td_sa.callp->sy_narg * sizeof(register_t));
1149 		break;
1150 
1151 	case PT_GET_SC_RET:
1152 		if ((td2->td_dbgflags & (TDB_SCX)) == 0
1153 #ifdef COMPAT_FREEBSD32
1154 		    || (wrap32 && !safe)
1155 #endif
1156 		    ) {
1157 			error = EINVAL;
1158 			break;
1159 		}
1160 		psr = addr;
1161 		bzero(psr, sizeof(*psr));
1162 		psr->sr_error = td2->td_errno;
1163 		if (psr->sr_error == 0) {
1164 			psr->sr_retval[0] = td2->td_retval[0];
1165 			psr->sr_retval[1] = td2->td_retval[1];
1166 		}
1167 		CTR4(KTR_PTRACE,
1168 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1169 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1170 		    psr->sr_retval[1]);
1171 		break;
1172 
1173 	case PT_STEP:
1174 	case PT_CONTINUE:
1175 	case PT_TO_SCE:
1176 	case PT_TO_SCX:
1177 	case PT_SYSCALL:
1178 	case PT_DETACH:
1179 		/* Zero means do not send any signal */
1180 		if (data < 0 || data > _SIG_MAXSIG) {
1181 			error = EINVAL;
1182 			break;
1183 		}
1184 
1185 		switch (req) {
1186 		case PT_STEP:
1187 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1188 			    td2->td_tid, p->p_pid, data);
1189 			error = ptrace_single_step(td2);
1190 			if (error)
1191 				goto out;
1192 			break;
1193 		case PT_CONTINUE:
1194 		case PT_TO_SCE:
1195 		case PT_TO_SCX:
1196 		case PT_SYSCALL:
1197 			if (addr != (void *)1) {
1198 				error = ptrace_set_pc(td2,
1199 				    (u_long)(uintfptr_t)addr);
1200 				if (error)
1201 					goto out;
1202 			}
1203 			switch (req) {
1204 			case PT_TO_SCE:
1205 				p->p_ptevents |= PTRACE_SCE;
1206 				CTR4(KTR_PTRACE,
1207 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1208 				    p->p_pid, p->p_ptevents,
1209 				    (u_long)(uintfptr_t)addr, data);
1210 				break;
1211 			case PT_TO_SCX:
1212 				p->p_ptevents |= PTRACE_SCX;
1213 				CTR4(KTR_PTRACE,
1214 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1215 				    p->p_pid, p->p_ptevents,
1216 				    (u_long)(uintfptr_t)addr, data);
1217 				break;
1218 			case PT_SYSCALL:
1219 				p->p_ptevents |= PTRACE_SYSCALL;
1220 				CTR4(KTR_PTRACE,
1221 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1222 				    p->p_pid, p->p_ptevents,
1223 				    (u_long)(uintfptr_t)addr, data);
1224 				break;
1225 			case PT_CONTINUE:
1226 				CTR3(KTR_PTRACE,
1227 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1228 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1229 				break;
1230 			}
1231 			break;
1232 		case PT_DETACH:
1233 			/*
1234 			 * Clear P_TRACED before reparenting
1235 			 * a detached process back to its original
1236 			 * parent.  Otherwise the debugee will be set
1237 			 * as an orphan of the debugger.
1238 			 */
1239 			p->p_flag &= ~(P_TRACED | P_WAITED);
1240 
1241 			/*
1242 			 * Reset the process parent.
1243 			 */
1244 			if (p->p_oppid != p->p_pptr->p_pid) {
1245 				PROC_LOCK(p->p_pptr);
1246 				sigqueue_take(p->p_ksi);
1247 				PROC_UNLOCK(p->p_pptr);
1248 
1249 				pp = proc_realparent(p);
1250 				proc_reparent(p, pp, false);
1251 				if (pp == initproc)
1252 					p->p_sigparent = SIGCHLD;
1253 				CTR3(KTR_PTRACE,
1254 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1255 				    p->p_pid, pp->p_pid, data);
1256 			} else {
1257 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1258 				    p->p_pid, data);
1259 			}
1260 
1261 			p->p_ptevents = 0;
1262 			FOREACH_THREAD_IN_PROC(p, td3) {
1263 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1264 					sigqueue_delete(&td3->td_sigqueue,
1265 					    SIGSTOP);
1266 				}
1267 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1268 				    TDB_SUSPEND);
1269 			}
1270 
1271 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1272 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1273 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1274 			}
1275 
1276 			/* should we send SIGCHLD? */
1277 			/* childproc_continued(p); */
1278 			break;
1279 		}
1280 
1281 		sx_xunlock(&proctree_lock);
1282 		proctree_locked = false;
1283 
1284 	sendsig:
1285 		MPASS(!proctree_locked);
1286 
1287 		/*
1288 		 * Clear the pending event for the thread that just
1289 		 * reported its event (p_xthread).  This may not be
1290 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1291 		 * the debugger is resuming a different thread.
1292 		 *
1293 		 * Deliver any pending signal via the reporting thread.
1294 		 */
1295 		MPASS(p->p_xthread != NULL);
1296 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1297 		p->p_xthread->td_xsig = data;
1298 		p->p_xthread = NULL;
1299 		p->p_xsig = data;
1300 
1301 		/*
1302 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1303 		 * always works immediately, even if another thread is
1304 		 * unsuspended first and attempts to handle a
1305 		 * different signal or if the POSIX.1b style signal
1306 		 * queue cannot accommodate any new signals.
1307 		 */
1308 		if (data == SIGKILL)
1309 			proc_wkilled(p);
1310 
1311 		/*
1312 		 * Unsuspend all threads.  To leave a thread
1313 		 * suspended, use PT_SUSPEND to suspend it before
1314 		 * continuing the process.
1315 		 */
1316 		ptrace_unsuspend(p);
1317 		break;
1318 
1319 	case PT_WRITE_I:
1320 	case PT_WRITE_D:
1321 		td2->td_dbgflags |= TDB_USERWR;
1322 		PROC_UNLOCK(p);
1323 		error = 0;
1324 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1325 		    sizeof(int)) != sizeof(int))
1326 			error = ENOMEM;
1327 		else
1328 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1329 			    p->p_pid, addr, data);
1330 		PROC_LOCK(p);
1331 		break;
1332 
1333 	case PT_READ_I:
1334 	case PT_READ_D:
1335 		PROC_UNLOCK(p);
1336 		error = tmp = 0;
1337 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1338 		    sizeof(int)) != sizeof(int))
1339 			error = ENOMEM;
1340 		else
1341 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1342 			    p->p_pid, addr, tmp);
1343 		td->td_retval[0] = tmp;
1344 		PROC_LOCK(p);
1345 		break;
1346 
1347 	case PT_IO:
1348 		piod = addr;
1349 		iov.iov_base = piod->piod_addr;
1350 		iov.iov_len = piod->piod_len;
1351 		uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1352 		uio.uio_resid = piod->piod_len;
1353 		uio.uio_iov = &iov;
1354 		uio.uio_iovcnt = 1;
1355 		uio.uio_segflg = UIO_USERSPACE;
1356 		uio.uio_td = td;
1357 		switch (piod->piod_op) {
1358 		case PIOD_READ_D:
1359 		case PIOD_READ_I:
1360 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1361 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1362 			uio.uio_rw = UIO_READ;
1363 			break;
1364 		case PIOD_WRITE_D:
1365 		case PIOD_WRITE_I:
1366 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1367 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1368 			td2->td_dbgflags |= TDB_USERWR;
1369 			uio.uio_rw = UIO_WRITE;
1370 			break;
1371 		default:
1372 			error = EINVAL;
1373 			goto out;
1374 		}
1375 		PROC_UNLOCK(p);
1376 		error = proc_rwmem(p, &uio);
1377 		piod->piod_len -= uio.uio_resid;
1378 		PROC_LOCK(p);
1379 		break;
1380 
1381 	case PT_KILL:
1382 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1383 		data = SIGKILL;
1384 		goto sendsig;	/* in PT_CONTINUE above */
1385 
1386 	case PT_SETREGS:
1387 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1388 		    p->p_pid);
1389 		td2->td_dbgflags |= TDB_USERWR;
1390 		error = PROC_WRITE(regs, td2, addr);
1391 		break;
1392 
1393 	case PT_GETREGS:
1394 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1395 		    p->p_pid);
1396 		error = PROC_READ(regs, td2, addr);
1397 		break;
1398 
1399 	case PT_SETFPREGS:
1400 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1401 		    p->p_pid);
1402 		td2->td_dbgflags |= TDB_USERWR;
1403 		error = PROC_WRITE(fpregs, td2, addr);
1404 		break;
1405 
1406 	case PT_GETFPREGS:
1407 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1408 		    p->p_pid);
1409 		error = PROC_READ(fpregs, td2, addr);
1410 		break;
1411 
1412 	case PT_SETDBREGS:
1413 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1414 		    p->p_pid);
1415 		td2->td_dbgflags |= TDB_USERWR;
1416 		error = PROC_WRITE(dbregs, td2, addr);
1417 		break;
1418 
1419 	case PT_GETDBREGS:
1420 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1421 		    p->p_pid);
1422 		error = PROC_READ(dbregs, td2, addr);
1423 		break;
1424 
1425 	case PT_SETREGSET:
1426 		CTR2(KTR_PTRACE, "PT_SETREGSET: tid %d (pid %d)", td2->td_tid,
1427 		    p->p_pid);
1428 		error = proc_write_regset(td2, data, addr);
1429 		break;
1430 
1431 	case PT_GETREGSET:
1432 		CTR2(KTR_PTRACE, "PT_GETREGSET: tid %d (pid %d)", td2->td_tid,
1433 		    p->p_pid);
1434 		error = proc_read_regset(td2, data, addr);
1435 		break;
1436 
1437 	case PT_LWPINFO:
1438 		if (data <= 0 || data > sizeof(*pl)) {
1439 			error = EINVAL;
1440 			break;
1441 		}
1442 		pl = addr;
1443 		bzero(pl, sizeof(*pl));
1444 		pl->pl_lwpid = td2->td_tid;
1445 		pl->pl_event = PL_EVENT_NONE;
1446 		pl->pl_flags = 0;
1447 		if (td2->td_dbgflags & TDB_XSIG) {
1448 			pl->pl_event = PL_EVENT_SIGNAL;
1449 			if (td2->td_si.si_signo != 0 &&
1450 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1451 			    + sizeof(pl->pl_siginfo)){
1452 				pl->pl_flags |= PL_FLAG_SI;
1453 				pl->pl_siginfo = td2->td_si;
1454 			}
1455 		}
1456 		if (td2->td_dbgflags & TDB_SCE)
1457 			pl->pl_flags |= PL_FLAG_SCE;
1458 		else if (td2->td_dbgflags & TDB_SCX)
1459 			pl->pl_flags |= PL_FLAG_SCX;
1460 		if (td2->td_dbgflags & TDB_EXEC)
1461 			pl->pl_flags |= PL_FLAG_EXEC;
1462 		if (td2->td_dbgflags & TDB_FORK) {
1463 			pl->pl_flags |= PL_FLAG_FORKED;
1464 			pl->pl_child_pid = td2->td_dbg_forked;
1465 			if (td2->td_dbgflags & TDB_VFORK)
1466 				pl->pl_flags |= PL_FLAG_VFORKED;
1467 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1468 		    TDB_VFORK)
1469 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1470 		if (td2->td_dbgflags & TDB_CHILD)
1471 			pl->pl_flags |= PL_FLAG_CHILD;
1472 		if (td2->td_dbgflags & TDB_BORN)
1473 			pl->pl_flags |= PL_FLAG_BORN;
1474 		if (td2->td_dbgflags & TDB_EXIT)
1475 			pl->pl_flags |= PL_FLAG_EXITED;
1476 		pl->pl_sigmask = td2->td_sigmask;
1477 		pl->pl_siglist = td2->td_siglist;
1478 		strcpy(pl->pl_tdname, td2->td_name);
1479 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1480 			pl->pl_syscall_code = td2->td_sa.code;
1481 			pl->pl_syscall_narg = td2->td_sa.callp->sy_narg;
1482 		} else {
1483 			pl->pl_syscall_code = 0;
1484 			pl->pl_syscall_narg = 0;
1485 		}
1486 		CTR6(KTR_PTRACE,
1487     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1488 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1489 		    pl->pl_child_pid, pl->pl_syscall_code);
1490 		break;
1491 
1492 	case PT_GETNUMLWPS:
1493 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1494 		    p->p_numthreads);
1495 		td->td_retval[0] = p->p_numthreads;
1496 		break;
1497 
1498 	case PT_GETLWPLIST:
1499 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1500 		    p->p_pid, data, p->p_numthreads);
1501 		if (data <= 0) {
1502 			error = EINVAL;
1503 			break;
1504 		}
1505 		num = imin(p->p_numthreads, data);
1506 		PROC_UNLOCK(p);
1507 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1508 		tmp = 0;
1509 		PROC_LOCK(p);
1510 		FOREACH_THREAD_IN_PROC(p, td2) {
1511 			if (tmp >= num)
1512 				break;
1513 			buf[tmp++] = td2->td_tid;
1514 		}
1515 		PROC_UNLOCK(p);
1516 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1517 		free(buf, M_TEMP);
1518 		if (!error)
1519 			td->td_retval[0] = tmp;
1520 		PROC_LOCK(p);
1521 		break;
1522 
1523 	case PT_VM_TIMESTAMP:
1524 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1525 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1526 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1527 		break;
1528 
1529 	case PT_VM_ENTRY:
1530 		PROC_UNLOCK(p);
1531 		error = ptrace_vm_entry(td, p, addr);
1532 		PROC_LOCK(p);
1533 		break;
1534 
1535 	case PT_COREDUMP:
1536 		pc = addr;
1537 		CTR2(KTR_PTRACE, "PT_COREDUMP: pid %d, fd %d",
1538 		    p->p_pid, pc->pc_fd);
1539 
1540 		if ((pc->pc_flags & ~(PC_COMPRESS | PC_ALL)) != 0) {
1541 			error = EINVAL;
1542 			break;
1543 		}
1544 		PROC_UNLOCK(p);
1545 
1546 		tcq = malloc(sizeof(*tcq), M_TEMP, M_WAITOK | M_ZERO);
1547 		fp = NULL;
1548 		error = fget_write(td, pc->pc_fd, &cap_write_rights, &fp);
1549 		if (error != 0)
1550 			goto coredump_cleanup_nofp;
1551 		if (fp->f_type != DTYPE_VNODE || fp->f_vnode->v_type != VREG) {
1552 			error = EPIPE;
1553 			goto coredump_cleanup;
1554 		}
1555 
1556 		PROC_LOCK(p);
1557 		error = proc_can_ptrace(td, p);
1558 		if (error != 0)
1559 			goto coredump_cleanup_locked;
1560 
1561 		td2 = ptrace_sel_coredump_thread(p);
1562 		if (td2 == NULL) {
1563 			error = EBUSY;
1564 			goto coredump_cleanup_locked;
1565 		}
1566 		KASSERT((td2->td_dbgflags & TDB_COREDUMPRQ) == 0,
1567 		    ("proc %d tid %d req coredump", p->p_pid, td2->td_tid));
1568 
1569 		tcq->tc_vp = fp->f_vnode;
1570 		tcq->tc_limit = pc->pc_limit == 0 ? OFF_MAX : pc->pc_limit;
1571 		tcq->tc_flags = SVC_PT_COREDUMP;
1572 		if ((pc->pc_flags & PC_COMPRESS) == 0)
1573 			tcq->tc_flags |= SVC_NOCOMPRESS;
1574 		if ((pc->pc_flags & PC_ALL) != 0)
1575 			tcq->tc_flags |= SVC_ALL;
1576 		td2->td_coredump = tcq;
1577 		td2->td_dbgflags |= TDB_COREDUMPRQ;
1578 		thread_run_flash(td2);
1579 		while ((td2->td_dbgflags & TDB_COREDUMPRQ) != 0)
1580 			msleep(p, &p->p_mtx, PPAUSE, "crdmp", 0);
1581 		error = tcq->tc_error;
1582 coredump_cleanup_locked:
1583 		PROC_UNLOCK(p);
1584 coredump_cleanup:
1585 		fdrop(fp, td);
1586 coredump_cleanup_nofp:
1587 		free(tcq, M_TEMP);
1588 		PROC_LOCK(p);
1589 		break;
1590 
1591 	default:
1592 #ifdef __HAVE_PTRACE_MACHDEP
1593 		if (req >= PT_FIRSTMACH) {
1594 			PROC_UNLOCK(p);
1595 			error = cpu_ptrace(td2, req, addr, data);
1596 			PROC_LOCK(p);
1597 		} else
1598 #endif
1599 			/* Unknown request. */
1600 			error = EINVAL;
1601 		break;
1602 	}
1603 out:
1604 	/* Drop our hold on this process now that the request has completed. */
1605 	_PRELE(p);
1606 fail:
1607 	if (p2_req_set) {
1608 		if ((p->p_flag2 & P2_PTRACEREQ) != 0)
1609 			wakeup(&p->p_flag2);
1610 		p->p_flag2 &= ~P2_PTRACEREQ;
1611 	}
1612 	PROC_UNLOCK(p);
1613 	if (proctree_locked)
1614 		sx_xunlock(&proctree_lock);
1615 	return (error);
1616 }
1617 #undef PROC_READ
1618 #undef PROC_WRITE
1619