xref: /freebsd/sys/kern/sys_process.c (revision f5b7695d2d5abd735064870ad43f4b9c723940c1)
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 
55 #include <machine/reg.h>
56 
57 #include <security/audit/audit.h>
58 
59 #include <vm/vm.h>
60 #include <vm/pmap.h>
61 #include <vm/vm_extern.h>
62 #include <vm/vm_map.h>
63 #include <vm/vm_kern.h>
64 #include <vm/vm_object.h>
65 #include <vm/vm_page.h>
66 #include <vm/vm_param.h>
67 
68 #ifdef COMPAT_FREEBSD32
69 #include <sys/procfs.h>
70 #include <compat/freebsd32/freebsd32_signal.h>
71 
72 struct ptrace_io_desc32 {
73 	int		piod_op;
74 	uint32_t	piod_offs;
75 	uint32_t	piod_addr;
76 	uint32_t	piod_len;
77 };
78 
79 struct ptrace_sc_ret32 {
80 	uint32_t	sr_retval[2];
81 	int		sr_error;
82 };
83 
84 struct ptrace_vm_entry32 {
85 	int		pve_entry;
86 	int		pve_timestamp;
87 	uint32_t	pve_start;
88 	uint32_t	pve_end;
89 	uint32_t	pve_offset;
90 	u_int		pve_prot;
91 	u_int		pve_pathlen;
92 	int32_t		pve_fileid;
93 	u_int		pve_fsid;
94 	uint32_t	pve_path;
95 };
96 #endif
97 
98 /*
99  * Functions implemented using PROC_ACTION():
100  *
101  * proc_read_regs(proc, regs)
102  *	Get the current user-visible register set from the process
103  *	and copy it into the regs structure (<machine/reg.h>).
104  *	The process is stopped at the time read_regs is called.
105  *
106  * proc_write_regs(proc, regs)
107  *	Update the current register set from the passed in regs
108  *	structure.  Take care to avoid clobbering special CPU
109  *	registers or privileged bits in the PSL.
110  *	Depending on the architecture this may have fix-up work to do,
111  *	especially if the IAR or PCW are modified.
112  *	The process is stopped at the time write_regs is called.
113  *
114  * proc_read_fpregs, proc_write_fpregs
115  *	deal with the floating point register set, otherwise as above.
116  *
117  * proc_read_dbregs, proc_write_dbregs
118  *	deal with the processor debug register set, otherwise as above.
119  *
120  * proc_sstep(proc)
121  *	Arrange for the process to trap after executing a single instruction.
122  */
123 
124 #define	PROC_ACTION(action) do {					\
125 	int error;							\
126 									\
127 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
128 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
129 		error = EIO;						\
130 	else								\
131 		error = (action);					\
132 	return (error);							\
133 } while(0)
134 
135 int
136 proc_read_regs(struct thread *td, struct reg *regs)
137 {
138 
139 	PROC_ACTION(fill_regs(td, regs));
140 }
141 
142 int
143 proc_write_regs(struct thread *td, struct reg *regs)
144 {
145 
146 	PROC_ACTION(set_regs(td, regs));
147 }
148 
149 int
150 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
151 {
152 
153 	PROC_ACTION(fill_dbregs(td, dbregs));
154 }
155 
156 int
157 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
158 {
159 
160 	PROC_ACTION(set_dbregs(td, dbregs));
161 }
162 
163 /*
164  * Ptrace doesn't support fpregs at all, and there are no security holes
165  * or translations for fpregs, so we can just copy them.
166  */
167 int
168 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
169 {
170 
171 	PROC_ACTION(fill_fpregs(td, fpregs));
172 }
173 
174 int
175 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
176 {
177 
178 	PROC_ACTION(set_fpregs(td, fpregs));
179 }
180 
181 #ifdef COMPAT_FREEBSD32
182 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
183 int
184 proc_read_regs32(struct thread *td, struct reg32 *regs32)
185 {
186 
187 	PROC_ACTION(fill_regs32(td, regs32));
188 }
189 
190 int
191 proc_write_regs32(struct thread *td, struct reg32 *regs32)
192 {
193 
194 	PROC_ACTION(set_regs32(td, regs32));
195 }
196 
197 int
198 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
199 {
200 
201 	PROC_ACTION(fill_dbregs32(td, dbregs32));
202 }
203 
204 int
205 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
206 {
207 
208 	PROC_ACTION(set_dbregs32(td, dbregs32));
209 }
210 
211 int
212 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
213 {
214 
215 	PROC_ACTION(fill_fpregs32(td, fpregs32));
216 }
217 
218 int
219 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
220 {
221 
222 	PROC_ACTION(set_fpregs32(td, fpregs32));
223 }
224 #endif
225 
226 int
227 proc_sstep(struct thread *td)
228 {
229 
230 	PROC_ACTION(ptrace_single_step(td));
231 }
232 
233 int
234 proc_rwmem(struct proc *p, struct uio *uio)
235 {
236 	vm_map_t map;
237 	vm_offset_t pageno;		/* page number */
238 	vm_prot_t reqprot;
239 	int error, fault_flags, page_offset, writing;
240 
241 	/*
242 	 * Assert that someone has locked this vmspace.  (Should be
243 	 * curthread but we can't assert that.)  This keeps the process
244 	 * from exiting out from under us until this operation completes.
245 	 */
246 	PROC_ASSERT_HELD(p);
247 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
248 
249 	/*
250 	 * The map we want...
251 	 */
252 	map = &p->p_vmspace->vm_map;
253 
254 	/*
255 	 * If we are writing, then we request vm_fault() to create a private
256 	 * copy of each page.  Since these copies will not be writeable by the
257 	 * process, we must explicity request that they be dirtied.
258 	 */
259 	writing = uio->uio_rw == UIO_WRITE;
260 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
261 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
262 
263 	/*
264 	 * Only map in one page at a time.  We don't have to, but it
265 	 * makes things easier.  This way is trivial - right?
266 	 */
267 	do {
268 		vm_offset_t uva;
269 		u_int len;
270 		vm_page_t m;
271 
272 		uva = (vm_offset_t)uio->uio_offset;
273 
274 		/*
275 		 * Get the page number of this segment.
276 		 */
277 		pageno = trunc_page(uva);
278 		page_offset = uva - pageno;
279 
280 		/*
281 		 * How many bytes to copy
282 		 */
283 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
284 
285 		/*
286 		 * Fault and hold the page on behalf of the process.
287 		 */
288 		error = vm_fault(map, pageno, reqprot, fault_flags, &m);
289 		if (error != KERN_SUCCESS) {
290 			if (error == KERN_RESOURCE_SHORTAGE)
291 				error = ENOMEM;
292 			else
293 				error = EFAULT;
294 			break;
295 		}
296 
297 		/*
298 		 * Now do the i/o move.
299 		 */
300 		error = uiomove_fromphys(&m, page_offset, len, uio);
301 
302 		/* Make the I-cache coherent for breakpoints. */
303 		if (writing && error == 0) {
304 			vm_map_lock_read(map);
305 			if (vm_map_check_protection(map, pageno, pageno +
306 			    PAGE_SIZE, VM_PROT_EXECUTE))
307 				vm_sync_icache(map, uva, len);
308 			vm_map_unlock_read(map);
309 		}
310 
311 		/*
312 		 * Release the page.
313 		 */
314 		vm_page_unwire(m, PQ_ACTIVE);
315 
316 	} while (error == 0 && uio->uio_resid > 0);
317 
318 	return (error);
319 }
320 
321 static ssize_t
322 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
323     size_t len, enum uio_rw rw)
324 {
325 	struct iovec iov;
326 	struct uio uio;
327 	ssize_t slen;
328 
329 	MPASS(len < SSIZE_MAX);
330 	slen = (ssize_t)len;
331 
332 	iov.iov_base = (caddr_t)buf;
333 	iov.iov_len = len;
334 	uio.uio_iov = &iov;
335 	uio.uio_iovcnt = 1;
336 	uio.uio_offset = va;
337 	uio.uio_resid = slen;
338 	uio.uio_segflg = UIO_SYSSPACE;
339 	uio.uio_rw = rw;
340 	uio.uio_td = td;
341 	proc_rwmem(p, &uio);
342 	if (uio.uio_resid == slen)
343 		return (-1);
344 	return (slen - uio.uio_resid);
345 }
346 
347 ssize_t
348 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
349     size_t len)
350 {
351 
352 	return (proc_iop(td, p, va, buf, len, UIO_READ));
353 }
354 
355 ssize_t
356 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
357     size_t len)
358 {
359 
360 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
361 }
362 
363 static int
364 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
365 {
366 	struct vattr vattr;
367 	vm_map_t map;
368 	vm_map_entry_t entry;
369 	vm_object_t obj, tobj, lobj;
370 	struct vmspace *vm;
371 	struct vnode *vp;
372 	char *freepath, *fullpath;
373 	u_int pathlen;
374 	int error, index;
375 
376 	error = 0;
377 	obj = NULL;
378 
379 	vm = vmspace_acquire_ref(p);
380 	map = &vm->vm_map;
381 	vm_map_lock_read(map);
382 
383 	do {
384 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
385 		    ("Submap in map header"));
386 		index = 0;
387 		VM_MAP_ENTRY_FOREACH(entry, map) {
388 			if (index >= pve->pve_entry &&
389 			    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) == 0)
390 				break;
391 			index++;
392 		}
393 		if (index < pve->pve_entry) {
394 			error = EINVAL;
395 			break;
396 		}
397 		if (entry == &map->header) {
398 			error = ENOENT;
399 			break;
400 		}
401 
402 		/* We got an entry. */
403 		pve->pve_entry = index + 1;
404 		pve->pve_timestamp = map->timestamp;
405 		pve->pve_start = entry->start;
406 		pve->pve_end = entry->end - 1;
407 		pve->pve_offset = entry->offset;
408 		pve->pve_prot = entry->protection;
409 
410 		/* Backing object's path needed? */
411 		if (pve->pve_pathlen == 0)
412 			break;
413 
414 		pathlen = pve->pve_pathlen;
415 		pve->pve_pathlen = 0;
416 
417 		obj = entry->object.vm_object;
418 		if (obj != NULL)
419 			VM_OBJECT_RLOCK(obj);
420 	} while (0);
421 
422 	vm_map_unlock_read(map);
423 
424 	pve->pve_fsid = VNOVAL;
425 	pve->pve_fileid = VNOVAL;
426 
427 	if (error == 0 && obj != NULL) {
428 		lobj = obj;
429 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
430 			if (tobj != obj)
431 				VM_OBJECT_RLOCK(tobj);
432 			if (lobj != obj)
433 				VM_OBJECT_RUNLOCK(lobj);
434 			lobj = tobj;
435 			pve->pve_offset += tobj->backing_object_offset;
436 		}
437 		vp = vm_object_vnode(lobj);
438 		if (vp != NULL)
439 			vref(vp);
440 		if (lobj != obj)
441 			VM_OBJECT_RUNLOCK(lobj);
442 		VM_OBJECT_RUNLOCK(obj);
443 
444 		if (vp != NULL) {
445 			freepath = NULL;
446 			fullpath = NULL;
447 			vn_fullpath(td, vp, &fullpath, &freepath);
448 			vn_lock(vp, LK_SHARED | LK_RETRY);
449 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
450 				pve->pve_fileid = vattr.va_fileid;
451 				pve->pve_fsid = vattr.va_fsid;
452 			}
453 			vput(vp);
454 
455 			if (fullpath != NULL) {
456 				pve->pve_pathlen = strlen(fullpath) + 1;
457 				if (pve->pve_pathlen <= pathlen) {
458 					error = copyout(fullpath, pve->pve_path,
459 					    pve->pve_pathlen);
460 				} else
461 					error = ENAMETOOLONG;
462 			}
463 			if (freepath != NULL)
464 				free(freepath, M_TEMP);
465 		}
466 	}
467 	vmspace_free(vm);
468 	if (error == 0)
469 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
470 		    p->p_pid, pve->pve_entry, pve->pve_start);
471 
472 	return (error);
473 }
474 
475 #ifdef COMPAT_FREEBSD32
476 static int
477 ptrace_vm_entry32(struct thread *td, struct proc *p,
478     struct ptrace_vm_entry32 *pve32)
479 {
480 	struct ptrace_vm_entry pve;
481 	int error;
482 
483 	pve.pve_entry = pve32->pve_entry;
484 	pve.pve_pathlen = pve32->pve_pathlen;
485 	pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
486 
487 	error = ptrace_vm_entry(td, p, &pve);
488 	if (error == 0) {
489 		pve32->pve_entry = pve.pve_entry;
490 		pve32->pve_timestamp = pve.pve_timestamp;
491 		pve32->pve_start = pve.pve_start;
492 		pve32->pve_end = pve.pve_end;
493 		pve32->pve_offset = pve.pve_offset;
494 		pve32->pve_prot = pve.pve_prot;
495 		pve32->pve_fileid = pve.pve_fileid;
496 		pve32->pve_fsid = pve.pve_fsid;
497 	}
498 
499 	pve32->pve_pathlen = pve.pve_pathlen;
500 	return (error);
501 }
502 
503 static void
504 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
505     struct ptrace_lwpinfo32 *pl32)
506 {
507 
508 	bzero(pl32, sizeof(*pl32));
509 	pl32->pl_lwpid = pl->pl_lwpid;
510 	pl32->pl_event = pl->pl_event;
511 	pl32->pl_flags = pl->pl_flags;
512 	pl32->pl_sigmask = pl->pl_sigmask;
513 	pl32->pl_siglist = pl->pl_siglist;
514 	siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
515 	strcpy(pl32->pl_tdname, pl->pl_tdname);
516 	pl32->pl_child_pid = pl->pl_child_pid;
517 	pl32->pl_syscall_code = pl->pl_syscall_code;
518 	pl32->pl_syscall_narg = pl->pl_syscall_narg;
519 }
520 
521 static void
522 ptrace_sc_ret_to32(const struct ptrace_sc_ret *psr,
523     struct ptrace_sc_ret32 *psr32)
524 {
525 
526 	bzero(psr32, sizeof(*psr32));
527 	psr32->sr_retval[0] = psr->sr_retval[0];
528 	psr32->sr_retval[1] = psr->sr_retval[1];
529 	psr32->sr_error = psr->sr_error;
530 }
531 #endif /* COMPAT_FREEBSD32 */
532 
533 /*
534  * Process debugging system call.
535  */
536 #ifndef _SYS_SYSPROTO_H_
537 struct ptrace_args {
538 	int	req;
539 	pid_t	pid;
540 	caddr_t	addr;
541 	int	data;
542 };
543 #endif
544 
545 #ifdef COMPAT_FREEBSD32
546 /*
547  * This CPP subterfuge is to try and reduce the number of ifdefs in
548  * the body of the code.
549  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
550  * becomes either:
551  *   copyin(uap->addr, &r.reg, sizeof r.reg);
552  * or
553  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
554  * .. except this is done at runtime.
555  */
556 #define	BZERO(a, s)		wrap32 ? \
557 	bzero(a ## 32, s ## 32) : \
558 	bzero(a, s)
559 #define	COPYIN(u, k, s)		wrap32 ? \
560 	copyin(u, k ## 32, s ## 32) : \
561 	copyin(u, k, s)
562 #define	COPYOUT(k, u, s)	wrap32 ? \
563 	copyout(k ## 32, u, s ## 32) : \
564 	copyout(k, u, s)
565 #else
566 #define	BZERO(a, s)		bzero(a, s)
567 #define	COPYIN(u, k, s)		copyin(u, k, s)
568 #define	COPYOUT(k, u, s)	copyout(k, u, s)
569 #endif
570 int
571 sys_ptrace(struct thread *td, struct ptrace_args *uap)
572 {
573 	/*
574 	 * XXX this obfuscation is to reduce stack usage, but the register
575 	 * structs may be too large to put on the stack anyway.
576 	 */
577 	union {
578 		struct ptrace_io_desc piod;
579 		struct ptrace_lwpinfo pl;
580 		struct ptrace_vm_entry pve;
581 		struct dbreg dbreg;
582 		struct fpreg fpreg;
583 		struct reg reg;
584 #ifdef COMPAT_FREEBSD32
585 		struct dbreg32 dbreg32;
586 		struct fpreg32 fpreg32;
587 		struct reg32 reg32;
588 		struct ptrace_io_desc32 piod32;
589 		struct ptrace_lwpinfo32 pl32;
590 		struct ptrace_vm_entry32 pve32;
591 #endif
592 		char args[sizeof(td->td_sa.args)];
593 		struct ptrace_sc_ret psr;
594 		int ptevents;
595 	} r;
596 	void *addr;
597 	int error = 0;
598 #ifdef COMPAT_FREEBSD32
599 	int wrap32 = 0;
600 
601 	if (SV_CURPROC_FLAG(SV_ILP32))
602 		wrap32 = 1;
603 #endif
604 	AUDIT_ARG_PID(uap->pid);
605 	AUDIT_ARG_CMD(uap->req);
606 	AUDIT_ARG_VALUE(uap->data);
607 	addr = &r;
608 	switch (uap->req) {
609 	case PT_GET_EVENT_MASK:
610 	case PT_LWPINFO:
611 	case PT_GET_SC_ARGS:
612 	case PT_GET_SC_RET:
613 		break;
614 	case PT_GETREGS:
615 		BZERO(&r.reg, sizeof r.reg);
616 		break;
617 	case PT_GETFPREGS:
618 		BZERO(&r.fpreg, sizeof r.fpreg);
619 		break;
620 	case PT_GETDBREGS:
621 		BZERO(&r.dbreg, sizeof r.dbreg);
622 		break;
623 	case PT_SETREGS:
624 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
625 		break;
626 	case PT_SETFPREGS:
627 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
628 		break;
629 	case PT_SETDBREGS:
630 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
631 		break;
632 	case PT_SET_EVENT_MASK:
633 		if (uap->data != sizeof(r.ptevents))
634 			error = EINVAL;
635 		else
636 			error = copyin(uap->addr, &r.ptevents, uap->data);
637 		break;
638 	case PT_IO:
639 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
640 		break;
641 	case PT_VM_ENTRY:
642 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
643 		break;
644 	default:
645 		addr = uap->addr;
646 		break;
647 	}
648 	if (error)
649 		return (error);
650 
651 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
652 	if (error)
653 		return (error);
654 
655 	switch (uap->req) {
656 	case PT_VM_ENTRY:
657 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
658 		break;
659 	case PT_IO:
660 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
661 		break;
662 	case PT_GETREGS:
663 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
664 		break;
665 	case PT_GETFPREGS:
666 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
667 		break;
668 	case PT_GETDBREGS:
669 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
670 		break;
671 	case PT_GET_EVENT_MASK:
672 		/* NB: The size in uap->data is validated in kern_ptrace(). */
673 		error = copyout(&r.ptevents, uap->addr, uap->data);
674 		break;
675 	case PT_LWPINFO:
676 		/* NB: The size in uap->data is validated in kern_ptrace(). */
677 		error = copyout(&r.pl, uap->addr, uap->data);
678 		break;
679 	case PT_GET_SC_ARGS:
680 		error = copyout(r.args, uap->addr, MIN(uap->data,
681 		    sizeof(r.args)));
682 		break;
683 	case PT_GET_SC_RET:
684 		error = copyout(&r.psr, uap->addr, MIN(uap->data,
685 		    sizeof(r.psr)));
686 		break;
687 	}
688 
689 	return (error);
690 }
691 #undef COPYIN
692 #undef COPYOUT
693 #undef BZERO
694 
695 #ifdef COMPAT_FREEBSD32
696 /*
697  *   PROC_READ(regs, td2, addr);
698  * becomes either:
699  *   proc_read_regs(td2, addr);
700  * or
701  *   proc_read_regs32(td2, addr);
702  * .. except this is done at runtime.  There is an additional
703  * complication in that PROC_WRITE disallows 32 bit consumers
704  * from writing to 64 bit address space targets.
705  */
706 #define	PROC_READ(w, t, a)	wrap32 ? \
707 	proc_read_ ## w ## 32(t, a) : \
708 	proc_read_ ## w (t, a)
709 #define	PROC_WRITE(w, t, a)	wrap32 ? \
710 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
711 	proc_write_ ## w (t, a)
712 #else
713 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
714 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
715 #endif
716 
717 void
718 proc_set_traced(struct proc *p, bool stop)
719 {
720 
721 	sx_assert(&proctree_lock, SX_XLOCKED);
722 	PROC_LOCK_ASSERT(p, MA_OWNED);
723 	p->p_flag |= P_TRACED;
724 	if (stop)
725 		p->p_flag2 |= P2_PTRACE_FSTP;
726 	p->p_ptevents = PTRACE_DEFAULT;
727 }
728 
729 int
730 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
731 {
732 	struct iovec iov;
733 	struct uio uio;
734 	struct proc *curp, *p, *pp;
735 	struct thread *td2 = NULL, *td3;
736 	struct ptrace_io_desc *piod = NULL;
737 	struct ptrace_lwpinfo *pl;
738 	struct ptrace_sc_ret *psr;
739 	int error, num, tmp;
740 	int proctree_locked = 0;
741 	lwpid_t tid = 0, *buf;
742 #ifdef COMPAT_FREEBSD32
743 	int wrap32 = 0, safe = 0;
744 	struct ptrace_io_desc32 *piod32 = NULL;
745 	struct ptrace_lwpinfo32 *pl32 = NULL;
746 	struct ptrace_sc_ret32 *psr32 = NULL;
747 	union {
748 		struct ptrace_lwpinfo pl;
749 		struct ptrace_sc_ret psr;
750 	} r;
751 #endif
752 
753 	curp = td->td_proc;
754 
755 	/* Lock proctree before locking the process. */
756 	switch (req) {
757 	case PT_TRACE_ME:
758 	case PT_ATTACH:
759 	case PT_STEP:
760 	case PT_CONTINUE:
761 	case PT_TO_SCE:
762 	case PT_TO_SCX:
763 	case PT_SYSCALL:
764 	case PT_FOLLOW_FORK:
765 	case PT_LWP_EVENTS:
766 	case PT_GET_EVENT_MASK:
767 	case PT_SET_EVENT_MASK:
768 	case PT_DETACH:
769 	case PT_GET_SC_ARGS:
770 		sx_xlock(&proctree_lock);
771 		proctree_locked = 1;
772 		break;
773 	default:
774 		break;
775 	}
776 
777 	if (req == PT_TRACE_ME) {
778 		p = td->td_proc;
779 		PROC_LOCK(p);
780 	} else {
781 		if (pid <= PID_MAX) {
782 			if ((p = pfind(pid)) == NULL) {
783 				if (proctree_locked)
784 					sx_xunlock(&proctree_lock);
785 				return (ESRCH);
786 			}
787 		} else {
788 			td2 = tdfind(pid, -1);
789 			if (td2 == NULL) {
790 				if (proctree_locked)
791 					sx_xunlock(&proctree_lock);
792 				return (ESRCH);
793 			}
794 			p = td2->td_proc;
795 			tid = pid;
796 			pid = p->p_pid;
797 		}
798 	}
799 	AUDIT_ARG_PROCESS(p);
800 
801 	if ((p->p_flag & P_WEXIT) != 0) {
802 		error = ESRCH;
803 		goto fail;
804 	}
805 	if ((error = p_cansee(td, p)) != 0)
806 		goto fail;
807 
808 	if ((error = p_candebug(td, p)) != 0)
809 		goto fail;
810 
811 	/*
812 	 * System processes can't be debugged.
813 	 */
814 	if ((p->p_flag & P_SYSTEM) != 0) {
815 		error = EINVAL;
816 		goto fail;
817 	}
818 
819 	if (tid == 0) {
820 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
821 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
822 			td2 = p->p_xthread;
823 		} else {
824 			td2 = FIRST_THREAD_IN_PROC(p);
825 		}
826 		tid = td2->td_tid;
827 	}
828 
829 #ifdef COMPAT_FREEBSD32
830 	/*
831 	 * Test if we're a 32 bit client and what the target is.
832 	 * Set the wrap controls accordingly.
833 	 */
834 	if (SV_CURPROC_FLAG(SV_ILP32)) {
835 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
836 			safe = 1;
837 		wrap32 = 1;
838 	}
839 #endif
840 	/*
841 	 * Permissions check
842 	 */
843 	switch (req) {
844 	case PT_TRACE_ME:
845 		/*
846 		 * Always legal, when there is a parent process which
847 		 * could trace us.  Otherwise, reject.
848 		 */
849 		if ((p->p_flag & P_TRACED) != 0) {
850 			error = EBUSY;
851 			goto fail;
852 		}
853 		if (p->p_pptr == initproc) {
854 			error = EPERM;
855 			goto fail;
856 		}
857 		break;
858 
859 	case PT_ATTACH:
860 		/* Self */
861 		if (p == td->td_proc) {
862 			error = EINVAL;
863 			goto fail;
864 		}
865 
866 		/* Already traced */
867 		if (p->p_flag & P_TRACED) {
868 			error = EBUSY;
869 			goto fail;
870 		}
871 
872 		/* Can't trace an ancestor if you're being traced. */
873 		if (curp->p_flag & P_TRACED) {
874 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
875 				if (pp == p) {
876 					error = EINVAL;
877 					goto fail;
878 				}
879 			}
880 		}
881 
882 		/* OK */
883 		break;
884 
885 	case PT_CLEARSTEP:
886 		/* Allow thread to clear single step for itself */
887 		if (td->td_tid == tid)
888 			break;
889 
890 		/* FALLTHROUGH */
891 	default:
892 		/* not being traced... */
893 		if ((p->p_flag & P_TRACED) == 0) {
894 			error = EPERM;
895 			goto fail;
896 		}
897 
898 		/* not being traced by YOU */
899 		if (p->p_pptr != td->td_proc) {
900 			error = EBUSY;
901 			goto fail;
902 		}
903 
904 		/* not currently stopped */
905 		if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
906 		    p->p_suspcount != p->p_numthreads  ||
907 		    (p->p_flag & P_WAITED) == 0) {
908 			error = EBUSY;
909 			goto fail;
910 		}
911 
912 		/* OK */
913 		break;
914 	}
915 
916 	/* Keep this process around until we finish this request. */
917 	_PHOLD(p);
918 
919 #ifdef FIX_SSTEP
920 	/*
921 	 * Single step fixup ala procfs
922 	 */
923 	FIX_SSTEP(td2);
924 #endif
925 
926 	/*
927 	 * Actually do the requests
928 	 */
929 
930 	td->td_retval[0] = 0;
931 
932 	switch (req) {
933 	case PT_TRACE_ME:
934 		/* set my trace flag and "owner" so it can read/write me */
935 		proc_set_traced(p, false);
936 		if (p->p_flag & P_PPWAIT)
937 			p->p_flag |= P_PPTRACE;
938 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
939 		break;
940 
941 	case PT_ATTACH:
942 		/* security check done above */
943 		/*
944 		 * It would be nice if the tracing relationship was separate
945 		 * from the parent relationship but that would require
946 		 * another set of links in the proc struct or for "wait"
947 		 * to scan the entire proc table.  To make life easier,
948 		 * we just re-parent the process we're trying to trace.
949 		 * The old parent is remembered so we can put things back
950 		 * on a "detach".
951 		 */
952 		proc_set_traced(p, true);
953 		proc_reparent(p, td->td_proc, false);
954 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
955 		    p->p_oppid);
956 
957 		sx_xunlock(&proctree_lock);
958 		proctree_locked = 0;
959 		MPASS(p->p_xthread == NULL);
960 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
961 
962 		/*
963 		 * If already stopped due to a stop signal, clear the
964 		 * existing stop before triggering a traced SIGSTOP.
965 		 */
966 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
967 			PROC_SLOCK(p);
968 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
969 			thread_unsuspend(p);
970 			PROC_SUNLOCK(p);
971 		}
972 
973 		kern_psignal(p, SIGSTOP);
974 		break;
975 
976 	case PT_CLEARSTEP:
977 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
978 		    p->p_pid);
979 		error = ptrace_clear_single_step(td2);
980 		break;
981 
982 	case PT_SETSTEP:
983 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
984 		    p->p_pid);
985 		error = ptrace_single_step(td2);
986 		break;
987 
988 	case PT_SUSPEND:
989 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
990 		    p->p_pid);
991 		td2->td_dbgflags |= TDB_SUSPEND;
992 		thread_lock(td2);
993 		td2->td_flags |= TDF_NEEDSUSPCHK;
994 		thread_unlock(td2);
995 		break;
996 
997 	case PT_RESUME:
998 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
999 		    p->p_pid);
1000 		td2->td_dbgflags &= ~TDB_SUSPEND;
1001 		break;
1002 
1003 	case PT_FOLLOW_FORK:
1004 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
1005 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
1006 		    data ? "enabled" : "disabled");
1007 		if (data)
1008 			p->p_ptevents |= PTRACE_FORK;
1009 		else
1010 			p->p_ptevents &= ~PTRACE_FORK;
1011 		break;
1012 
1013 	case PT_LWP_EVENTS:
1014 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
1015 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
1016 		    data ? "enabled" : "disabled");
1017 		if (data)
1018 			p->p_ptevents |= PTRACE_LWP;
1019 		else
1020 			p->p_ptevents &= ~PTRACE_LWP;
1021 		break;
1022 
1023 	case PT_GET_EVENT_MASK:
1024 		if (data != sizeof(p->p_ptevents)) {
1025 			error = EINVAL;
1026 			break;
1027 		}
1028 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1029 		    p->p_ptevents);
1030 		*(int *)addr = p->p_ptevents;
1031 		break;
1032 
1033 	case PT_SET_EVENT_MASK:
1034 		if (data != sizeof(p->p_ptevents)) {
1035 			error = EINVAL;
1036 			break;
1037 		}
1038 		tmp = *(int *)addr;
1039 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1040 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1041 			error = EINVAL;
1042 			break;
1043 		}
1044 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1045 		    p->p_pid, p->p_ptevents, tmp);
1046 		p->p_ptevents = tmp;
1047 		break;
1048 
1049 	case PT_GET_SC_ARGS:
1050 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1051 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1052 #ifdef COMPAT_FREEBSD32
1053 		    || (wrap32 && !safe)
1054 #endif
1055 		    ) {
1056 			error = EINVAL;
1057 			break;
1058 		}
1059 		bzero(addr, sizeof(td2->td_sa.args));
1060 #ifdef COMPAT_FREEBSD32
1061 		if (wrap32)
1062 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1063 				((uint32_t *)addr)[num] = (uint32_t)
1064 				    td2->td_sa.args[num];
1065 		else
1066 #endif
1067 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1068 			    sizeof(register_t));
1069 		break;
1070 
1071 	case PT_GET_SC_RET:
1072 		if ((td2->td_dbgflags & (TDB_SCX)) == 0
1073 #ifdef COMPAT_FREEBSD32
1074 		    || (wrap32 && !safe)
1075 #endif
1076 		    ) {
1077 			error = EINVAL;
1078 			break;
1079 		}
1080 #ifdef COMPAT_FREEBSD32
1081 		if (wrap32) {
1082 			psr = &r.psr;
1083 			psr32 = addr;
1084 		} else
1085 #endif
1086 		psr = addr;
1087 		bzero(psr, sizeof(*psr));
1088 		psr->sr_error = td2->td_errno;
1089 		if (psr->sr_error == 0) {
1090 			psr->sr_retval[0] = td2->td_retval[0];
1091 			psr->sr_retval[1] = td2->td_retval[1];
1092 		}
1093 #ifdef COMPAT_FREEBSD32
1094 		if (wrap32)
1095 			ptrace_sc_ret_to32(psr, psr32);
1096 #endif
1097 		CTR4(KTR_PTRACE,
1098 		    "PT_GET_SC_RET: pid %d error %d retval %#lx,%#lx",
1099 		    p->p_pid, psr->sr_error, psr->sr_retval[0],
1100 		    psr->sr_retval[1]);
1101 		break;
1102 
1103 	case PT_STEP:
1104 	case PT_CONTINUE:
1105 	case PT_TO_SCE:
1106 	case PT_TO_SCX:
1107 	case PT_SYSCALL:
1108 	case PT_DETACH:
1109 		/* Zero means do not send any signal */
1110 		if (data < 0 || data > _SIG_MAXSIG) {
1111 			error = EINVAL;
1112 			break;
1113 		}
1114 
1115 		switch (req) {
1116 		case PT_STEP:
1117 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1118 			    td2->td_tid, p->p_pid, data);
1119 			error = ptrace_single_step(td2);
1120 			if (error)
1121 				goto out;
1122 			break;
1123 		case PT_CONTINUE:
1124 		case PT_TO_SCE:
1125 		case PT_TO_SCX:
1126 		case PT_SYSCALL:
1127 			if (addr != (void *)1) {
1128 				error = ptrace_set_pc(td2,
1129 				    (u_long)(uintfptr_t)addr);
1130 				if (error)
1131 					goto out;
1132 			}
1133 			switch (req) {
1134 			case PT_TO_SCE:
1135 				p->p_ptevents |= PTRACE_SCE;
1136 				CTR4(KTR_PTRACE,
1137 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1138 				    p->p_pid, p->p_ptevents,
1139 				    (u_long)(uintfptr_t)addr, data);
1140 				break;
1141 			case PT_TO_SCX:
1142 				p->p_ptevents |= PTRACE_SCX;
1143 				CTR4(KTR_PTRACE,
1144 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1145 				    p->p_pid, p->p_ptevents,
1146 				    (u_long)(uintfptr_t)addr, data);
1147 				break;
1148 			case PT_SYSCALL:
1149 				p->p_ptevents |= PTRACE_SYSCALL;
1150 				CTR4(KTR_PTRACE,
1151 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1152 				    p->p_pid, p->p_ptevents,
1153 				    (u_long)(uintfptr_t)addr, data);
1154 				break;
1155 			case PT_CONTINUE:
1156 				CTR3(KTR_PTRACE,
1157 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1158 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1159 				break;
1160 			}
1161 			break;
1162 		case PT_DETACH:
1163 			/*
1164 			 * Reset the process parent.
1165 			 *
1166 			 * NB: This clears P_TRACED before reparenting
1167 			 * a detached process back to its original
1168 			 * parent.  Otherwise the debugee will be set
1169 			 * as an orphan of the debugger.
1170 			 */
1171 			p->p_flag &= ~(P_TRACED | P_WAITED);
1172 			if (p->p_oppid != p->p_pptr->p_pid) {
1173 				PROC_LOCK(p->p_pptr);
1174 				sigqueue_take(p->p_ksi);
1175 				PROC_UNLOCK(p->p_pptr);
1176 
1177 				pp = proc_realparent(p);
1178 				proc_reparent(p, pp, false);
1179 				if (pp == initproc)
1180 					p->p_sigparent = SIGCHLD;
1181 				CTR3(KTR_PTRACE,
1182 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1183 				    p->p_pid, pp->p_pid, data);
1184 			} else
1185 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1186 				    p->p_pid, data);
1187 			p->p_ptevents = 0;
1188 			FOREACH_THREAD_IN_PROC(p, td3) {
1189 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1190 					sigqueue_delete(&td3->td_sigqueue,
1191 					    SIGSTOP);
1192 				}
1193 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1194 				    TDB_SUSPEND);
1195 			}
1196 
1197 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1198 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1199 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1200 			}
1201 
1202 			/* should we send SIGCHLD? */
1203 			/* childproc_continued(p); */
1204 			break;
1205 		}
1206 
1207 		sx_xunlock(&proctree_lock);
1208 		proctree_locked = 0;
1209 
1210 	sendsig:
1211 		MPASS(proctree_locked == 0);
1212 
1213 		/*
1214 		 * Clear the pending event for the thread that just
1215 		 * reported its event (p_xthread).  This may not be
1216 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1217 		 * the debugger is resuming a different thread.
1218 		 *
1219 		 * Deliver any pending signal via the reporting thread.
1220 		 */
1221 		MPASS(p->p_xthread != NULL);
1222 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1223 		p->p_xthread->td_xsig = data;
1224 		p->p_xthread = NULL;
1225 		p->p_xsig = data;
1226 
1227 		/*
1228 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1229 		 * always works immediately, even if another thread is
1230 		 * unsuspended first and attempts to handle a
1231 		 * different signal or if the POSIX.1b style signal
1232 		 * queue cannot accommodate any new signals.
1233 		 */
1234 		if (data == SIGKILL)
1235 			proc_wkilled(p);
1236 
1237 		/*
1238 		 * Unsuspend all threads.  To leave a thread
1239 		 * suspended, use PT_SUSPEND to suspend it before
1240 		 * continuing the process.
1241 		 */
1242 		PROC_SLOCK(p);
1243 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1244 		thread_unsuspend(p);
1245 		PROC_SUNLOCK(p);
1246 		break;
1247 
1248 	case PT_WRITE_I:
1249 	case PT_WRITE_D:
1250 		td2->td_dbgflags |= TDB_USERWR;
1251 		PROC_UNLOCK(p);
1252 		error = 0;
1253 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1254 		    sizeof(int)) != sizeof(int))
1255 			error = ENOMEM;
1256 		else
1257 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1258 			    p->p_pid, addr, data);
1259 		PROC_LOCK(p);
1260 		break;
1261 
1262 	case PT_READ_I:
1263 	case PT_READ_D:
1264 		PROC_UNLOCK(p);
1265 		error = tmp = 0;
1266 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1267 		    sizeof(int)) != sizeof(int))
1268 			error = ENOMEM;
1269 		else
1270 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1271 			    p->p_pid, addr, tmp);
1272 		td->td_retval[0] = tmp;
1273 		PROC_LOCK(p);
1274 		break;
1275 
1276 	case PT_IO:
1277 #ifdef COMPAT_FREEBSD32
1278 		if (wrap32) {
1279 			piod32 = addr;
1280 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1281 			iov.iov_len = piod32->piod_len;
1282 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1283 			uio.uio_resid = piod32->piod_len;
1284 		} else
1285 #endif
1286 		{
1287 			piod = addr;
1288 			iov.iov_base = piod->piod_addr;
1289 			iov.iov_len = piod->piod_len;
1290 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1291 			uio.uio_resid = piod->piod_len;
1292 		}
1293 		uio.uio_iov = &iov;
1294 		uio.uio_iovcnt = 1;
1295 		uio.uio_segflg = UIO_USERSPACE;
1296 		uio.uio_td = td;
1297 #ifdef COMPAT_FREEBSD32
1298 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1299 #else
1300 		tmp = piod->piod_op;
1301 #endif
1302 		switch (tmp) {
1303 		case PIOD_READ_D:
1304 		case PIOD_READ_I:
1305 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1306 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1307 			uio.uio_rw = UIO_READ;
1308 			break;
1309 		case PIOD_WRITE_D:
1310 		case PIOD_WRITE_I:
1311 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1312 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1313 			td2->td_dbgflags |= TDB_USERWR;
1314 			uio.uio_rw = UIO_WRITE;
1315 			break;
1316 		default:
1317 			error = EINVAL;
1318 			goto out;
1319 		}
1320 		PROC_UNLOCK(p);
1321 		error = proc_rwmem(p, &uio);
1322 #ifdef COMPAT_FREEBSD32
1323 		if (wrap32)
1324 			piod32->piod_len -= uio.uio_resid;
1325 		else
1326 #endif
1327 			piod->piod_len -= uio.uio_resid;
1328 		PROC_LOCK(p);
1329 		break;
1330 
1331 	case PT_KILL:
1332 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1333 		data = SIGKILL;
1334 		goto sendsig;	/* in PT_CONTINUE above */
1335 
1336 	case PT_SETREGS:
1337 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1338 		    p->p_pid);
1339 		td2->td_dbgflags |= TDB_USERWR;
1340 		error = PROC_WRITE(regs, td2, addr);
1341 		break;
1342 
1343 	case PT_GETREGS:
1344 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1345 		    p->p_pid);
1346 		error = PROC_READ(regs, td2, addr);
1347 		break;
1348 
1349 	case PT_SETFPREGS:
1350 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1351 		    p->p_pid);
1352 		td2->td_dbgflags |= TDB_USERWR;
1353 		error = PROC_WRITE(fpregs, td2, addr);
1354 		break;
1355 
1356 	case PT_GETFPREGS:
1357 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1358 		    p->p_pid);
1359 		error = PROC_READ(fpregs, td2, addr);
1360 		break;
1361 
1362 	case PT_SETDBREGS:
1363 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1364 		    p->p_pid);
1365 		td2->td_dbgflags |= TDB_USERWR;
1366 		error = PROC_WRITE(dbregs, td2, addr);
1367 		break;
1368 
1369 	case PT_GETDBREGS:
1370 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1371 		    p->p_pid);
1372 		error = PROC_READ(dbregs, td2, addr);
1373 		break;
1374 
1375 	case PT_LWPINFO:
1376 		if (data <= 0 ||
1377 #ifdef COMPAT_FREEBSD32
1378 		    (!wrap32 && data > sizeof(*pl)) ||
1379 		    (wrap32 && data > sizeof(*pl32))) {
1380 #else
1381 		    data > sizeof(*pl)) {
1382 #endif
1383 			error = EINVAL;
1384 			break;
1385 		}
1386 #ifdef COMPAT_FREEBSD32
1387 		if (wrap32) {
1388 			pl = &r.pl;
1389 			pl32 = addr;
1390 		} else
1391 #endif
1392 		pl = addr;
1393 		bzero(pl, sizeof(*pl));
1394 		pl->pl_lwpid = td2->td_tid;
1395 		pl->pl_event = PL_EVENT_NONE;
1396 		pl->pl_flags = 0;
1397 		if (td2->td_dbgflags & TDB_XSIG) {
1398 			pl->pl_event = PL_EVENT_SIGNAL;
1399 			if (td2->td_si.si_signo != 0 &&
1400 #ifdef COMPAT_FREEBSD32
1401 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1402 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1403 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1404 			    pl_siginfo) + sizeof(struct siginfo32)))
1405 #else
1406 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1407 			    + sizeof(pl->pl_siginfo)
1408 #endif
1409 			){
1410 				pl->pl_flags |= PL_FLAG_SI;
1411 				pl->pl_siginfo = td2->td_si;
1412 			}
1413 		}
1414 		if (td2->td_dbgflags & TDB_SCE)
1415 			pl->pl_flags |= PL_FLAG_SCE;
1416 		else if (td2->td_dbgflags & TDB_SCX)
1417 			pl->pl_flags |= PL_FLAG_SCX;
1418 		if (td2->td_dbgflags & TDB_EXEC)
1419 			pl->pl_flags |= PL_FLAG_EXEC;
1420 		if (td2->td_dbgflags & TDB_FORK) {
1421 			pl->pl_flags |= PL_FLAG_FORKED;
1422 			pl->pl_child_pid = td2->td_dbg_forked;
1423 			if (td2->td_dbgflags & TDB_VFORK)
1424 				pl->pl_flags |= PL_FLAG_VFORKED;
1425 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1426 		    TDB_VFORK)
1427 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1428 		if (td2->td_dbgflags & TDB_CHILD)
1429 			pl->pl_flags |= PL_FLAG_CHILD;
1430 		if (td2->td_dbgflags & TDB_BORN)
1431 			pl->pl_flags |= PL_FLAG_BORN;
1432 		if (td2->td_dbgflags & TDB_EXIT)
1433 			pl->pl_flags |= PL_FLAG_EXITED;
1434 		pl->pl_sigmask = td2->td_sigmask;
1435 		pl->pl_siglist = td2->td_siglist;
1436 		strcpy(pl->pl_tdname, td2->td_name);
1437 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1438 			pl->pl_syscall_code = td2->td_sa.code;
1439 			pl->pl_syscall_narg = td2->td_sa.narg;
1440 		} else {
1441 			pl->pl_syscall_code = 0;
1442 			pl->pl_syscall_narg = 0;
1443 		}
1444 #ifdef COMPAT_FREEBSD32
1445 		if (wrap32)
1446 			ptrace_lwpinfo_to32(pl, pl32);
1447 #endif
1448 		CTR6(KTR_PTRACE,
1449     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1450 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1451 		    pl->pl_child_pid, pl->pl_syscall_code);
1452 		break;
1453 
1454 	case PT_GETNUMLWPS:
1455 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1456 		    p->p_numthreads);
1457 		td->td_retval[0] = p->p_numthreads;
1458 		break;
1459 
1460 	case PT_GETLWPLIST:
1461 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1462 		    p->p_pid, data, p->p_numthreads);
1463 		if (data <= 0) {
1464 			error = EINVAL;
1465 			break;
1466 		}
1467 		num = imin(p->p_numthreads, data);
1468 		PROC_UNLOCK(p);
1469 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1470 		tmp = 0;
1471 		PROC_LOCK(p);
1472 		FOREACH_THREAD_IN_PROC(p, td2) {
1473 			if (tmp >= num)
1474 				break;
1475 			buf[tmp++] = td2->td_tid;
1476 		}
1477 		PROC_UNLOCK(p);
1478 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1479 		free(buf, M_TEMP);
1480 		if (!error)
1481 			td->td_retval[0] = tmp;
1482 		PROC_LOCK(p);
1483 		break;
1484 
1485 	case PT_VM_TIMESTAMP:
1486 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1487 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1488 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1489 		break;
1490 
1491 	case PT_VM_ENTRY:
1492 		PROC_UNLOCK(p);
1493 #ifdef COMPAT_FREEBSD32
1494 		if (wrap32)
1495 			error = ptrace_vm_entry32(td, p, addr);
1496 		else
1497 #endif
1498 		error = ptrace_vm_entry(td, p, addr);
1499 		PROC_LOCK(p);
1500 		break;
1501 
1502 	default:
1503 #ifdef __HAVE_PTRACE_MACHDEP
1504 		if (req >= PT_FIRSTMACH) {
1505 			PROC_UNLOCK(p);
1506 			error = cpu_ptrace(td2, req, addr, data);
1507 			PROC_LOCK(p);
1508 		} else
1509 #endif
1510 			/* Unknown request. */
1511 			error = EINVAL;
1512 		break;
1513 	}
1514 
1515 out:
1516 	/* Drop our hold on this process now that the request has completed. */
1517 	_PRELE(p);
1518 fail:
1519 	PROC_UNLOCK(p);
1520 	if (proctree_locked)
1521 		sx_xunlock(&proctree_lock);
1522 	return (error);
1523 }
1524 #undef PROC_READ
1525 #undef PROC_WRITE
1526