xref: /freebsd/sys/kern/sys_process.c (revision 6683132d54bd6d589889e43dabdc53d35e38a028)
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/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/syscallsubr.h>
43 #include <sys/sysent.h>
44 #include <sys/sysproto.h>
45 #include <sys/pioctl.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_vm_entry32 {
80 	int		pve_entry;
81 	int		pve_timestamp;
82 	uint32_t	pve_start;
83 	uint32_t	pve_end;
84 	uint32_t	pve_offset;
85 	u_int		pve_prot;
86 	u_int		pve_pathlen;
87 	int32_t		pve_fileid;
88 	u_int		pve_fsid;
89 	uint32_t	pve_path;
90 };
91 #endif
92 
93 /*
94  * Functions implemented using PROC_ACTION():
95  *
96  * proc_read_regs(proc, regs)
97  *	Get the current user-visible register set from the process
98  *	and copy it into the regs structure (<machine/reg.h>).
99  *	The process is stopped at the time read_regs is called.
100  *
101  * proc_write_regs(proc, regs)
102  *	Update the current register set from the passed in regs
103  *	structure.  Take care to avoid clobbering special CPU
104  *	registers or privileged bits in the PSL.
105  *	Depending on the architecture this may have fix-up work to do,
106  *	especially if the IAR or PCW are modified.
107  *	The process is stopped at the time write_regs is called.
108  *
109  * proc_read_fpregs, proc_write_fpregs
110  *	deal with the floating point register set, otherwise as above.
111  *
112  * proc_read_dbregs, proc_write_dbregs
113  *	deal with the processor debug register set, otherwise as above.
114  *
115  * proc_sstep(proc)
116  *	Arrange for the process to trap after executing a single instruction.
117  */
118 
119 #define	PROC_ACTION(action) do {					\
120 	int error;							\
121 									\
122 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
123 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
124 		error = EIO;						\
125 	else								\
126 		error = (action);					\
127 	return (error);							\
128 } while(0)
129 
130 int
131 proc_read_regs(struct thread *td, struct reg *regs)
132 {
133 
134 	PROC_ACTION(fill_regs(td, regs));
135 }
136 
137 int
138 proc_write_regs(struct thread *td, struct reg *regs)
139 {
140 
141 	PROC_ACTION(set_regs(td, regs));
142 }
143 
144 int
145 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
146 {
147 
148 	PROC_ACTION(fill_dbregs(td, dbregs));
149 }
150 
151 int
152 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
153 {
154 
155 	PROC_ACTION(set_dbregs(td, dbregs));
156 }
157 
158 /*
159  * Ptrace doesn't support fpregs at all, and there are no security holes
160  * or translations for fpregs, so we can just copy them.
161  */
162 int
163 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
164 {
165 
166 	PROC_ACTION(fill_fpregs(td, fpregs));
167 }
168 
169 int
170 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
171 {
172 
173 	PROC_ACTION(set_fpregs(td, fpregs));
174 }
175 
176 #ifdef COMPAT_FREEBSD32
177 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
178 int
179 proc_read_regs32(struct thread *td, struct reg32 *regs32)
180 {
181 
182 	PROC_ACTION(fill_regs32(td, regs32));
183 }
184 
185 int
186 proc_write_regs32(struct thread *td, struct reg32 *regs32)
187 {
188 
189 	PROC_ACTION(set_regs32(td, regs32));
190 }
191 
192 int
193 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
194 {
195 
196 	PROC_ACTION(fill_dbregs32(td, dbregs32));
197 }
198 
199 int
200 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
201 {
202 
203 	PROC_ACTION(set_dbregs32(td, dbregs32));
204 }
205 
206 int
207 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
208 {
209 
210 	PROC_ACTION(fill_fpregs32(td, fpregs32));
211 }
212 
213 int
214 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
215 {
216 
217 	PROC_ACTION(set_fpregs32(td, fpregs32));
218 }
219 #endif
220 
221 int
222 proc_sstep(struct thread *td)
223 {
224 
225 	PROC_ACTION(ptrace_single_step(td));
226 }
227 
228 int
229 proc_rwmem(struct proc *p, struct uio *uio)
230 {
231 	vm_map_t map;
232 	vm_offset_t pageno;		/* page number */
233 	vm_prot_t reqprot;
234 	int error, fault_flags, page_offset, writing;
235 
236 	/*
237 	 * Assert that someone has locked this vmspace.  (Should be
238 	 * curthread but we can't assert that.)  This keeps the process
239 	 * from exiting out from under us until this operation completes.
240 	 */
241 	PROC_ASSERT_HELD(p);
242 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
243 
244 	/*
245 	 * The map we want...
246 	 */
247 	map = &p->p_vmspace->vm_map;
248 
249 	/*
250 	 * If we are writing, then we request vm_fault() to create a private
251 	 * copy of each page.  Since these copies will not be writeable by the
252 	 * process, we must explicity request that they be dirtied.
253 	 */
254 	writing = uio->uio_rw == UIO_WRITE;
255 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
256 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
257 
258 	/*
259 	 * Only map in one page at a time.  We don't have to, but it
260 	 * makes things easier.  This way is trivial - right?
261 	 */
262 	do {
263 		vm_offset_t uva;
264 		u_int len;
265 		vm_page_t m;
266 
267 		uva = (vm_offset_t)uio->uio_offset;
268 
269 		/*
270 		 * Get the page number of this segment.
271 		 */
272 		pageno = trunc_page(uva);
273 		page_offset = uva - pageno;
274 
275 		/*
276 		 * How many bytes to copy
277 		 */
278 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
279 
280 		/*
281 		 * Fault and hold the page on behalf of the process.
282 		 */
283 		error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
284 		if (error != KERN_SUCCESS) {
285 			if (error == KERN_RESOURCE_SHORTAGE)
286 				error = ENOMEM;
287 			else
288 				error = EFAULT;
289 			break;
290 		}
291 
292 		/*
293 		 * Now do the i/o move.
294 		 */
295 		error = uiomove_fromphys(&m, page_offset, len, uio);
296 
297 		/* Make the I-cache coherent for breakpoints. */
298 		if (writing && error == 0) {
299 			vm_map_lock_read(map);
300 			if (vm_map_check_protection(map, pageno, pageno +
301 			    PAGE_SIZE, VM_PROT_EXECUTE))
302 				vm_sync_icache(map, uva, len);
303 			vm_map_unlock_read(map);
304 		}
305 
306 		/*
307 		 * Release the page.
308 		 */
309 		vm_page_lock(m);
310 		vm_page_unhold(m);
311 		vm_page_unlock(m);
312 
313 	} while (error == 0 && uio->uio_resid > 0);
314 
315 	return (error);
316 }
317 
318 static ssize_t
319 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
320     size_t len, enum uio_rw rw)
321 {
322 	struct iovec iov;
323 	struct uio uio;
324 	ssize_t slen;
325 
326 	MPASS(len < SSIZE_MAX);
327 	slen = (ssize_t)len;
328 
329 	iov.iov_base = (caddr_t)buf;
330 	iov.iov_len = len;
331 	uio.uio_iov = &iov;
332 	uio.uio_iovcnt = 1;
333 	uio.uio_offset = va;
334 	uio.uio_resid = slen;
335 	uio.uio_segflg = UIO_SYSSPACE;
336 	uio.uio_rw = rw;
337 	uio.uio_td = td;
338 	proc_rwmem(p, &uio);
339 	if (uio.uio_resid == slen)
340 		return (-1);
341 	return (slen - uio.uio_resid);
342 }
343 
344 ssize_t
345 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
346     size_t len)
347 {
348 
349 	return (proc_iop(td, p, va, buf, len, UIO_READ));
350 }
351 
352 ssize_t
353 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
354     size_t len)
355 {
356 
357 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
358 }
359 
360 static int
361 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
362 {
363 	struct vattr vattr;
364 	vm_map_t map;
365 	vm_map_entry_t entry;
366 	vm_object_t obj, tobj, lobj;
367 	struct vmspace *vm;
368 	struct vnode *vp;
369 	char *freepath, *fullpath;
370 	u_int pathlen;
371 	int error, index;
372 
373 	error = 0;
374 	obj = NULL;
375 
376 	vm = vmspace_acquire_ref(p);
377 	map = &vm->vm_map;
378 	vm_map_lock_read(map);
379 
380 	do {
381 		entry = map->header.next;
382 		index = 0;
383 		while (index < pve->pve_entry && entry != &map->header) {
384 			entry = entry->next;
385 			index++;
386 		}
387 		if (index != pve->pve_entry) {
388 			error = EINVAL;
389 			break;
390 		}
391 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
392 		    ("Submap in map header"));
393 		while ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
394 			entry = entry->next;
395 			index++;
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 #endif /* COMPAT_FREEBSD32 */
521 
522 /*
523  * Process debugging system call.
524  */
525 #ifndef _SYS_SYSPROTO_H_
526 struct ptrace_args {
527 	int	req;
528 	pid_t	pid;
529 	caddr_t	addr;
530 	int	data;
531 };
532 #endif
533 
534 #ifdef COMPAT_FREEBSD32
535 /*
536  * This CPP subterfuge is to try and reduce the number of ifdefs in
537  * the body of the code.
538  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
539  * becomes either:
540  *   copyin(uap->addr, &r.reg, sizeof r.reg);
541  * or
542  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
543  * .. except this is done at runtime.
544  */
545 #define	BZERO(a, s)		wrap32 ? \
546 	bzero(a ## 32, s ## 32) : \
547 	bzero(a, s)
548 #define	COPYIN(u, k, s)		wrap32 ? \
549 	copyin(u, k ## 32, s ## 32) : \
550 	copyin(u, k, s)
551 #define	COPYOUT(k, u, s)	wrap32 ? \
552 	copyout(k ## 32, u, s ## 32) : \
553 	copyout(k, u, s)
554 #else
555 #define	BZERO(a, s)		bzero(a, s)
556 #define	COPYIN(u, k, s)		copyin(u, k, s)
557 #define	COPYOUT(k, u, s)	copyout(k, u, s)
558 #endif
559 int
560 sys_ptrace(struct thread *td, struct ptrace_args *uap)
561 {
562 	/*
563 	 * XXX this obfuscation is to reduce stack usage, but the register
564 	 * structs may be too large to put on the stack anyway.
565 	 */
566 	union {
567 		struct ptrace_io_desc piod;
568 		struct ptrace_lwpinfo pl;
569 		struct ptrace_vm_entry pve;
570 		struct dbreg dbreg;
571 		struct fpreg fpreg;
572 		struct reg reg;
573 #ifdef COMPAT_FREEBSD32
574 		struct dbreg32 dbreg32;
575 		struct fpreg32 fpreg32;
576 		struct reg32 reg32;
577 		struct ptrace_io_desc32 piod32;
578 		struct ptrace_lwpinfo32 pl32;
579 		struct ptrace_vm_entry32 pve32;
580 #endif
581 		char args[sizeof(td->td_sa.args)];
582 		int ptevents;
583 	} r;
584 	void *addr;
585 	int error = 0;
586 #ifdef COMPAT_FREEBSD32
587 	int wrap32 = 0;
588 
589 	if (SV_CURPROC_FLAG(SV_ILP32))
590 		wrap32 = 1;
591 #endif
592 	AUDIT_ARG_PID(uap->pid);
593 	AUDIT_ARG_CMD(uap->req);
594 	AUDIT_ARG_VALUE(uap->data);
595 	addr = &r;
596 	switch (uap->req) {
597 	case PT_GET_EVENT_MASK:
598 	case PT_LWPINFO:
599 	case PT_GET_SC_ARGS:
600 		break;
601 	case PT_GETREGS:
602 		BZERO(&r.reg, sizeof r.reg);
603 		break;
604 	case PT_GETFPREGS:
605 		BZERO(&r.fpreg, sizeof r.fpreg);
606 		break;
607 	case PT_GETDBREGS:
608 		BZERO(&r.dbreg, sizeof r.dbreg);
609 		break;
610 	case PT_SETREGS:
611 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
612 		break;
613 	case PT_SETFPREGS:
614 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
615 		break;
616 	case PT_SETDBREGS:
617 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
618 		break;
619 	case PT_SET_EVENT_MASK:
620 		if (uap->data != sizeof(r.ptevents))
621 			error = EINVAL;
622 		else
623 			error = copyin(uap->addr, &r.ptevents, uap->data);
624 		break;
625 	case PT_IO:
626 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
627 		break;
628 	case PT_VM_ENTRY:
629 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
630 		break;
631 	default:
632 		addr = uap->addr;
633 		break;
634 	}
635 	if (error)
636 		return (error);
637 
638 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
639 	if (error)
640 		return (error);
641 
642 	switch (uap->req) {
643 	case PT_VM_ENTRY:
644 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
645 		break;
646 	case PT_IO:
647 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
648 		break;
649 	case PT_GETREGS:
650 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
651 		break;
652 	case PT_GETFPREGS:
653 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
654 		break;
655 	case PT_GETDBREGS:
656 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
657 		break;
658 	case PT_GET_EVENT_MASK:
659 		/* NB: The size in uap->data is validated in kern_ptrace(). */
660 		error = copyout(&r.ptevents, uap->addr, uap->data);
661 		break;
662 	case PT_LWPINFO:
663 		/* NB: The size in uap->data is validated in kern_ptrace(). */
664 		error = copyout(&r.pl, uap->addr, uap->data);
665 		break;
666 	case PT_GET_SC_ARGS:
667 		error = copyout(r.args, uap->addr, MIN(uap->data,
668 		    sizeof(r.args)));
669 		break;
670 	}
671 
672 	return (error);
673 }
674 #undef COPYIN
675 #undef COPYOUT
676 #undef BZERO
677 
678 #ifdef COMPAT_FREEBSD32
679 /*
680  *   PROC_READ(regs, td2, addr);
681  * becomes either:
682  *   proc_read_regs(td2, addr);
683  * or
684  *   proc_read_regs32(td2, addr);
685  * .. except this is done at runtime.  There is an additional
686  * complication in that PROC_WRITE disallows 32 bit consumers
687  * from writing to 64 bit address space targets.
688  */
689 #define	PROC_READ(w, t, a)	wrap32 ? \
690 	proc_read_ ## w ## 32(t, a) : \
691 	proc_read_ ## w (t, a)
692 #define	PROC_WRITE(w, t, a)	wrap32 ? \
693 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
694 	proc_write_ ## w (t, a)
695 #else
696 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
697 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
698 #endif
699 
700 void
701 proc_set_traced(struct proc *p, bool stop)
702 {
703 
704 	sx_assert(&proctree_lock, SX_XLOCKED);
705 	PROC_LOCK_ASSERT(p, MA_OWNED);
706 	p->p_flag |= P_TRACED;
707 	if (stop)
708 		p->p_flag2 |= P2_PTRACE_FSTP;
709 	p->p_ptevents = PTRACE_DEFAULT;
710 }
711 
712 int
713 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
714 {
715 	struct iovec iov;
716 	struct uio uio;
717 	struct proc *curp, *p, *pp;
718 	struct thread *td2 = NULL, *td3;
719 	struct ptrace_io_desc *piod = NULL;
720 	struct ptrace_lwpinfo *pl;
721 	int error, num, tmp;
722 	int proctree_locked = 0;
723 	lwpid_t tid = 0, *buf;
724 #ifdef COMPAT_FREEBSD32
725 	int wrap32 = 0, safe = 0;
726 	struct ptrace_io_desc32 *piod32 = NULL;
727 	struct ptrace_lwpinfo32 *pl32 = NULL;
728 	struct ptrace_lwpinfo plr;
729 #endif
730 
731 	curp = td->td_proc;
732 
733 	/* Lock proctree before locking the process. */
734 	switch (req) {
735 	case PT_TRACE_ME:
736 	case PT_ATTACH:
737 	case PT_STEP:
738 	case PT_CONTINUE:
739 	case PT_TO_SCE:
740 	case PT_TO_SCX:
741 	case PT_SYSCALL:
742 	case PT_FOLLOW_FORK:
743 	case PT_LWP_EVENTS:
744 	case PT_GET_EVENT_MASK:
745 	case PT_SET_EVENT_MASK:
746 	case PT_DETACH:
747 	case PT_GET_SC_ARGS:
748 		sx_xlock(&proctree_lock);
749 		proctree_locked = 1;
750 		break;
751 	default:
752 		break;
753 	}
754 
755 	if (req == PT_TRACE_ME) {
756 		p = td->td_proc;
757 		PROC_LOCK(p);
758 	} else {
759 		if (pid <= PID_MAX) {
760 			if ((p = pfind(pid)) == NULL) {
761 				if (proctree_locked)
762 					sx_xunlock(&proctree_lock);
763 				return (ESRCH);
764 			}
765 		} else {
766 			td2 = tdfind(pid, -1);
767 			if (td2 == NULL) {
768 				if (proctree_locked)
769 					sx_xunlock(&proctree_lock);
770 				return (ESRCH);
771 			}
772 			p = td2->td_proc;
773 			tid = pid;
774 			pid = p->p_pid;
775 		}
776 	}
777 	AUDIT_ARG_PROCESS(p);
778 
779 	if ((p->p_flag & P_WEXIT) != 0) {
780 		error = ESRCH;
781 		goto fail;
782 	}
783 	if ((error = p_cansee(td, p)) != 0)
784 		goto fail;
785 
786 	if ((error = p_candebug(td, p)) != 0)
787 		goto fail;
788 
789 	/*
790 	 * System processes can't be debugged.
791 	 */
792 	if ((p->p_flag & P_SYSTEM) != 0) {
793 		error = EINVAL;
794 		goto fail;
795 	}
796 
797 	if (tid == 0) {
798 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
799 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
800 			td2 = p->p_xthread;
801 		} else {
802 			td2 = FIRST_THREAD_IN_PROC(p);
803 		}
804 		tid = td2->td_tid;
805 	}
806 
807 #ifdef COMPAT_FREEBSD32
808 	/*
809 	 * Test if we're a 32 bit client and what the target is.
810 	 * Set the wrap controls accordingly.
811 	 */
812 	if (SV_CURPROC_FLAG(SV_ILP32)) {
813 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
814 			safe = 1;
815 		wrap32 = 1;
816 	}
817 #endif
818 	/*
819 	 * Permissions check
820 	 */
821 	switch (req) {
822 	case PT_TRACE_ME:
823 		/*
824 		 * Always legal, when there is a parent process which
825 		 * could trace us.  Otherwise, reject.
826 		 */
827 		if ((p->p_flag & P_TRACED) != 0) {
828 			error = EBUSY;
829 			goto fail;
830 		}
831 		if (p->p_pptr == initproc) {
832 			error = EPERM;
833 			goto fail;
834 		}
835 		break;
836 
837 	case PT_ATTACH:
838 		/* Self */
839 		if (p == td->td_proc) {
840 			error = EINVAL;
841 			goto fail;
842 		}
843 
844 		/* Already traced */
845 		if (p->p_flag & P_TRACED) {
846 			error = EBUSY;
847 			goto fail;
848 		}
849 
850 		/* Can't trace an ancestor if you're being traced. */
851 		if (curp->p_flag & P_TRACED) {
852 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
853 				if (pp == p) {
854 					error = EINVAL;
855 					goto fail;
856 				}
857 			}
858 		}
859 
860 
861 		/* OK */
862 		break;
863 
864 	case PT_CLEARSTEP:
865 		/* Allow thread to clear single step for itself */
866 		if (td->td_tid == tid)
867 			break;
868 
869 		/* FALLTHROUGH */
870 	default:
871 		/* not being traced... */
872 		if ((p->p_flag & P_TRACED) == 0) {
873 			error = EPERM;
874 			goto fail;
875 		}
876 
877 		/* not being traced by YOU */
878 		if (p->p_pptr != td->td_proc) {
879 			error = EBUSY;
880 			goto fail;
881 		}
882 
883 		/* not currently stopped */
884 		if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
885 		    p->p_suspcount != p->p_numthreads  ||
886 		    (p->p_flag & P_WAITED) == 0) {
887 			error = EBUSY;
888 			goto fail;
889 		}
890 
891 		/* OK */
892 		break;
893 	}
894 
895 	/* Keep this process around until we finish this request. */
896 	_PHOLD(p);
897 
898 #ifdef FIX_SSTEP
899 	/*
900 	 * Single step fixup ala procfs
901 	 */
902 	FIX_SSTEP(td2);
903 #endif
904 
905 	/*
906 	 * Actually do the requests
907 	 */
908 
909 	td->td_retval[0] = 0;
910 
911 	switch (req) {
912 	case PT_TRACE_ME:
913 		/* set my trace flag and "owner" so it can read/write me */
914 		proc_set_traced(p, false);
915 		if (p->p_flag & P_PPWAIT)
916 			p->p_flag |= P_PPTRACE;
917 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
918 		break;
919 
920 	case PT_ATTACH:
921 		/* security check done above */
922 		/*
923 		 * It would be nice if the tracing relationship was separate
924 		 * from the parent relationship but that would require
925 		 * another set of links in the proc struct or for "wait"
926 		 * to scan the entire proc table.  To make life easier,
927 		 * we just re-parent the process we're trying to trace.
928 		 * The old parent is remembered so we can put things back
929 		 * on a "detach".
930 		 */
931 		proc_set_traced(p, true);
932 		if (p->p_pptr != td->td_proc) {
933 			proc_reparent(p, td->td_proc, false);
934 		}
935 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
936 		    p->p_oppid);
937 
938 		sx_xunlock(&proctree_lock);
939 		proctree_locked = 0;
940 		MPASS(p->p_xthread == NULL);
941 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
942 
943 		/*
944 		 * If already stopped due to a stop signal, clear the
945 		 * existing stop before triggering a traced SIGSTOP.
946 		 */
947 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
948 			PROC_SLOCK(p);
949 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
950 			thread_unsuspend(p);
951 			PROC_SUNLOCK(p);
952 		}
953 
954 		kern_psignal(p, SIGSTOP);
955 		break;
956 
957 	case PT_CLEARSTEP:
958 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
959 		    p->p_pid);
960 		error = ptrace_clear_single_step(td2);
961 		break;
962 
963 	case PT_SETSTEP:
964 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
965 		    p->p_pid);
966 		error = ptrace_single_step(td2);
967 		break;
968 
969 	case PT_SUSPEND:
970 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
971 		    p->p_pid);
972 		td2->td_dbgflags |= TDB_SUSPEND;
973 		thread_lock(td2);
974 		td2->td_flags |= TDF_NEEDSUSPCHK;
975 		thread_unlock(td2);
976 		break;
977 
978 	case PT_RESUME:
979 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
980 		    p->p_pid);
981 		td2->td_dbgflags &= ~TDB_SUSPEND;
982 		break;
983 
984 	case PT_FOLLOW_FORK:
985 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
986 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
987 		    data ? "enabled" : "disabled");
988 		if (data)
989 			p->p_ptevents |= PTRACE_FORK;
990 		else
991 			p->p_ptevents &= ~PTRACE_FORK;
992 		break;
993 
994 	case PT_LWP_EVENTS:
995 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
996 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
997 		    data ? "enabled" : "disabled");
998 		if (data)
999 			p->p_ptevents |= PTRACE_LWP;
1000 		else
1001 			p->p_ptevents &= ~PTRACE_LWP;
1002 		break;
1003 
1004 	case PT_GET_EVENT_MASK:
1005 		if (data != sizeof(p->p_ptevents)) {
1006 			error = EINVAL;
1007 			break;
1008 		}
1009 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1010 		    p->p_ptevents);
1011 		*(int *)addr = p->p_ptevents;
1012 		break;
1013 
1014 	case PT_SET_EVENT_MASK:
1015 		if (data != sizeof(p->p_ptevents)) {
1016 			error = EINVAL;
1017 			break;
1018 		}
1019 		tmp = *(int *)addr;
1020 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1021 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1022 			error = EINVAL;
1023 			break;
1024 		}
1025 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1026 		    p->p_pid, p->p_ptevents, tmp);
1027 		p->p_ptevents = tmp;
1028 		break;
1029 
1030 	case PT_GET_SC_ARGS:
1031 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1032 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1033 #ifdef COMPAT_FREEBSD32
1034 		    || (wrap32 && !safe)
1035 #endif
1036 		    ) {
1037 			error = EINVAL;
1038 			break;
1039 		}
1040 		bzero(addr, sizeof(td2->td_sa.args));
1041 #ifdef COMPAT_FREEBSD32
1042 		if (wrap32)
1043 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1044 				((uint32_t *)addr)[num] = (uint32_t)
1045 				    td2->td_sa.args[num];
1046 		else
1047 #endif
1048 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1049 			    sizeof(register_t));
1050 		break;
1051 
1052 	case PT_STEP:
1053 	case PT_CONTINUE:
1054 	case PT_TO_SCE:
1055 	case PT_TO_SCX:
1056 	case PT_SYSCALL:
1057 	case PT_DETACH:
1058 		/* Zero means do not send any signal */
1059 		if (data < 0 || data > _SIG_MAXSIG) {
1060 			error = EINVAL;
1061 			break;
1062 		}
1063 
1064 		switch (req) {
1065 		case PT_STEP:
1066 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1067 			    td2->td_tid, p->p_pid, data);
1068 			error = ptrace_single_step(td2);
1069 			if (error)
1070 				goto out;
1071 			break;
1072 		case PT_CONTINUE:
1073 		case PT_TO_SCE:
1074 		case PT_TO_SCX:
1075 		case PT_SYSCALL:
1076 			if (addr != (void *)1) {
1077 				error = ptrace_set_pc(td2,
1078 				    (u_long)(uintfptr_t)addr);
1079 				if (error)
1080 					goto out;
1081 			}
1082 			switch (req) {
1083 			case PT_TO_SCE:
1084 				p->p_ptevents |= PTRACE_SCE;
1085 				CTR4(KTR_PTRACE,
1086 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1087 				    p->p_pid, p->p_ptevents,
1088 				    (u_long)(uintfptr_t)addr, data);
1089 				break;
1090 			case PT_TO_SCX:
1091 				p->p_ptevents |= PTRACE_SCX;
1092 				CTR4(KTR_PTRACE,
1093 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1094 				    p->p_pid, p->p_ptevents,
1095 				    (u_long)(uintfptr_t)addr, data);
1096 				break;
1097 			case PT_SYSCALL:
1098 				p->p_ptevents |= PTRACE_SYSCALL;
1099 				CTR4(KTR_PTRACE,
1100 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1101 				    p->p_pid, p->p_ptevents,
1102 				    (u_long)(uintfptr_t)addr, data);
1103 				break;
1104 			case PT_CONTINUE:
1105 				CTR3(KTR_PTRACE,
1106 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1107 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1108 				break;
1109 			}
1110 			break;
1111 		case PT_DETACH:
1112 			/*
1113 			 * Reset the process parent.
1114 			 *
1115 			 * NB: This clears P_TRACED before reparenting
1116 			 * a detached process back to its original
1117 			 * parent.  Otherwise the debugee will be set
1118 			 * as an orphan of the debugger.
1119 			 */
1120 			p->p_flag &= ~(P_TRACED | P_WAITED);
1121 			if (p->p_oppid != p->p_pptr->p_pid) {
1122 				PROC_LOCK(p->p_pptr);
1123 				sigqueue_take(p->p_ksi);
1124 				PROC_UNLOCK(p->p_pptr);
1125 
1126 				pp = proc_realparent(p);
1127 				proc_reparent(p, pp, false);
1128 				if (pp == initproc)
1129 					p->p_sigparent = SIGCHLD;
1130 				CTR3(KTR_PTRACE,
1131 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1132 				    p->p_pid, pp->p_pid, data);
1133 			} else
1134 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1135 				    p->p_pid, data);
1136 			p->p_ptevents = 0;
1137 			FOREACH_THREAD_IN_PROC(p, td3) {
1138 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1139 					sigqueue_delete(&td3->td_sigqueue,
1140 					    SIGSTOP);
1141 				}
1142 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1143 				    TDB_SUSPEND);
1144 			}
1145 
1146 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1147 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1148 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1149 			}
1150 
1151 			/* should we send SIGCHLD? */
1152 			/* childproc_continued(p); */
1153 			break;
1154 		}
1155 
1156 		sx_xunlock(&proctree_lock);
1157 		proctree_locked = 0;
1158 
1159 	sendsig:
1160 		MPASS(proctree_locked == 0);
1161 
1162 		/*
1163 		 * Clear the pending event for the thread that just
1164 		 * reported its event (p_xthread).  This may not be
1165 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1166 		 * the debugger is resuming a different thread.
1167 		 *
1168 		 * Deliver any pending signal via the reporting thread.
1169 		 */
1170 		MPASS(p->p_xthread != NULL);
1171 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1172 		p->p_xthread->td_xsig = data;
1173 		p->p_xthread = NULL;
1174 		p->p_xsig = data;
1175 
1176 		/*
1177 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1178 		 * always works immediately, even if another thread is
1179 		 * unsuspended first and attempts to handle a
1180 		 * different signal or if the POSIX.1b style signal
1181 		 * queue cannot accommodate any new signals.
1182 		 */
1183 		if (data == SIGKILL)
1184 			proc_wkilled(p);
1185 
1186 		/*
1187 		 * Unsuspend all threads.  To leave a thread
1188 		 * suspended, use PT_SUSPEND to suspend it before
1189 		 * continuing the process.
1190 		 */
1191 		PROC_SLOCK(p);
1192 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1193 		thread_unsuspend(p);
1194 		PROC_SUNLOCK(p);
1195 		break;
1196 
1197 	case PT_WRITE_I:
1198 	case PT_WRITE_D:
1199 		td2->td_dbgflags |= TDB_USERWR;
1200 		PROC_UNLOCK(p);
1201 		error = 0;
1202 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1203 		    sizeof(int)) != sizeof(int))
1204 			error = ENOMEM;
1205 		else
1206 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1207 			    p->p_pid, addr, data);
1208 		PROC_LOCK(p);
1209 		break;
1210 
1211 	case PT_READ_I:
1212 	case PT_READ_D:
1213 		PROC_UNLOCK(p);
1214 		error = tmp = 0;
1215 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1216 		    sizeof(int)) != sizeof(int))
1217 			error = ENOMEM;
1218 		else
1219 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1220 			    p->p_pid, addr, tmp);
1221 		td->td_retval[0] = tmp;
1222 		PROC_LOCK(p);
1223 		break;
1224 
1225 	case PT_IO:
1226 #ifdef COMPAT_FREEBSD32
1227 		if (wrap32) {
1228 			piod32 = addr;
1229 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1230 			iov.iov_len = piod32->piod_len;
1231 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1232 			uio.uio_resid = piod32->piod_len;
1233 		} else
1234 #endif
1235 		{
1236 			piod = addr;
1237 			iov.iov_base = piod->piod_addr;
1238 			iov.iov_len = piod->piod_len;
1239 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1240 			uio.uio_resid = piod->piod_len;
1241 		}
1242 		uio.uio_iov = &iov;
1243 		uio.uio_iovcnt = 1;
1244 		uio.uio_segflg = UIO_USERSPACE;
1245 		uio.uio_td = td;
1246 #ifdef COMPAT_FREEBSD32
1247 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1248 #else
1249 		tmp = piod->piod_op;
1250 #endif
1251 		switch (tmp) {
1252 		case PIOD_READ_D:
1253 		case PIOD_READ_I:
1254 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1255 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1256 			uio.uio_rw = UIO_READ;
1257 			break;
1258 		case PIOD_WRITE_D:
1259 		case PIOD_WRITE_I:
1260 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1261 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1262 			td2->td_dbgflags |= TDB_USERWR;
1263 			uio.uio_rw = UIO_WRITE;
1264 			break;
1265 		default:
1266 			error = EINVAL;
1267 			goto out;
1268 		}
1269 		PROC_UNLOCK(p);
1270 		error = proc_rwmem(p, &uio);
1271 #ifdef COMPAT_FREEBSD32
1272 		if (wrap32)
1273 			piod32->piod_len -= uio.uio_resid;
1274 		else
1275 #endif
1276 			piod->piod_len -= uio.uio_resid;
1277 		PROC_LOCK(p);
1278 		break;
1279 
1280 	case PT_KILL:
1281 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1282 		data = SIGKILL;
1283 		goto sendsig;	/* in PT_CONTINUE above */
1284 
1285 	case PT_SETREGS:
1286 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1287 		    p->p_pid);
1288 		td2->td_dbgflags |= TDB_USERWR;
1289 		error = PROC_WRITE(regs, td2, addr);
1290 		break;
1291 
1292 	case PT_GETREGS:
1293 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1294 		    p->p_pid);
1295 		error = PROC_READ(regs, td2, addr);
1296 		break;
1297 
1298 	case PT_SETFPREGS:
1299 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1300 		    p->p_pid);
1301 		td2->td_dbgflags |= TDB_USERWR;
1302 		error = PROC_WRITE(fpregs, td2, addr);
1303 		break;
1304 
1305 	case PT_GETFPREGS:
1306 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1307 		    p->p_pid);
1308 		error = PROC_READ(fpregs, td2, addr);
1309 		break;
1310 
1311 	case PT_SETDBREGS:
1312 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1313 		    p->p_pid);
1314 		td2->td_dbgflags |= TDB_USERWR;
1315 		error = PROC_WRITE(dbregs, td2, addr);
1316 		break;
1317 
1318 	case PT_GETDBREGS:
1319 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1320 		    p->p_pid);
1321 		error = PROC_READ(dbregs, td2, addr);
1322 		break;
1323 
1324 	case PT_LWPINFO:
1325 		if (data <= 0 ||
1326 #ifdef COMPAT_FREEBSD32
1327 		    (!wrap32 && data > sizeof(*pl)) ||
1328 		    (wrap32 && data > sizeof(*pl32))) {
1329 #else
1330 		    data > sizeof(*pl)) {
1331 #endif
1332 			error = EINVAL;
1333 			break;
1334 		}
1335 #ifdef COMPAT_FREEBSD32
1336 		if (wrap32) {
1337 			pl = &plr;
1338 			pl32 = addr;
1339 		} else
1340 #endif
1341 		pl = addr;
1342 		bzero(pl, sizeof(*pl));
1343 		pl->pl_lwpid = td2->td_tid;
1344 		pl->pl_event = PL_EVENT_NONE;
1345 		pl->pl_flags = 0;
1346 		if (td2->td_dbgflags & TDB_XSIG) {
1347 			pl->pl_event = PL_EVENT_SIGNAL;
1348 			if (td2->td_si.si_signo != 0 &&
1349 #ifdef COMPAT_FREEBSD32
1350 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1351 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1352 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1353 			    pl_siginfo) + sizeof(struct siginfo32)))
1354 #else
1355 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1356 			    + sizeof(pl->pl_siginfo)
1357 #endif
1358 			){
1359 				pl->pl_flags |= PL_FLAG_SI;
1360 				pl->pl_siginfo = td2->td_si;
1361 			}
1362 		}
1363 		if (td2->td_dbgflags & TDB_SCE)
1364 			pl->pl_flags |= PL_FLAG_SCE;
1365 		else if (td2->td_dbgflags & TDB_SCX)
1366 			pl->pl_flags |= PL_FLAG_SCX;
1367 		if (td2->td_dbgflags & TDB_EXEC)
1368 			pl->pl_flags |= PL_FLAG_EXEC;
1369 		if (td2->td_dbgflags & TDB_FORK) {
1370 			pl->pl_flags |= PL_FLAG_FORKED;
1371 			pl->pl_child_pid = td2->td_dbg_forked;
1372 			if (td2->td_dbgflags & TDB_VFORK)
1373 				pl->pl_flags |= PL_FLAG_VFORKED;
1374 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1375 		    TDB_VFORK)
1376 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1377 		if (td2->td_dbgflags & TDB_CHILD)
1378 			pl->pl_flags |= PL_FLAG_CHILD;
1379 		if (td2->td_dbgflags & TDB_BORN)
1380 			pl->pl_flags |= PL_FLAG_BORN;
1381 		if (td2->td_dbgflags & TDB_EXIT)
1382 			pl->pl_flags |= PL_FLAG_EXITED;
1383 		pl->pl_sigmask = td2->td_sigmask;
1384 		pl->pl_siglist = td2->td_siglist;
1385 		strcpy(pl->pl_tdname, td2->td_name);
1386 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1387 			pl->pl_syscall_code = td2->td_sa.code;
1388 			pl->pl_syscall_narg = td2->td_sa.narg;
1389 		} else {
1390 			pl->pl_syscall_code = 0;
1391 			pl->pl_syscall_narg = 0;
1392 		}
1393 #ifdef COMPAT_FREEBSD32
1394 		if (wrap32)
1395 			ptrace_lwpinfo_to32(pl, pl32);
1396 #endif
1397 		CTR6(KTR_PTRACE,
1398     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1399 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1400 		    pl->pl_child_pid, pl->pl_syscall_code);
1401 		break;
1402 
1403 	case PT_GETNUMLWPS:
1404 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1405 		    p->p_numthreads);
1406 		td->td_retval[0] = p->p_numthreads;
1407 		break;
1408 
1409 	case PT_GETLWPLIST:
1410 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1411 		    p->p_pid, data, p->p_numthreads);
1412 		if (data <= 0) {
1413 			error = EINVAL;
1414 			break;
1415 		}
1416 		num = imin(p->p_numthreads, data);
1417 		PROC_UNLOCK(p);
1418 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1419 		tmp = 0;
1420 		PROC_LOCK(p);
1421 		FOREACH_THREAD_IN_PROC(p, td2) {
1422 			if (tmp >= num)
1423 				break;
1424 			buf[tmp++] = td2->td_tid;
1425 		}
1426 		PROC_UNLOCK(p);
1427 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1428 		free(buf, M_TEMP);
1429 		if (!error)
1430 			td->td_retval[0] = tmp;
1431 		PROC_LOCK(p);
1432 		break;
1433 
1434 	case PT_VM_TIMESTAMP:
1435 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1436 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1437 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1438 		break;
1439 
1440 	case PT_VM_ENTRY:
1441 		PROC_UNLOCK(p);
1442 #ifdef COMPAT_FREEBSD32
1443 		if (wrap32)
1444 			error = ptrace_vm_entry32(td, p, addr);
1445 		else
1446 #endif
1447 		error = ptrace_vm_entry(td, p, addr);
1448 		PROC_LOCK(p);
1449 		break;
1450 
1451 	default:
1452 #ifdef __HAVE_PTRACE_MACHDEP
1453 		if (req >= PT_FIRSTMACH) {
1454 			PROC_UNLOCK(p);
1455 			error = cpu_ptrace(td2, req, addr, data);
1456 			PROC_LOCK(p);
1457 		} else
1458 #endif
1459 			/* Unknown request. */
1460 			error = EINVAL;
1461 		break;
1462 	}
1463 
1464 out:
1465 	/* Drop our hold on this process now that the request has completed. */
1466 	_PRELE(p);
1467 fail:
1468 	PROC_UNLOCK(p);
1469 	if (proctree_locked)
1470 		sx_xunlock(&proctree_lock);
1471 	return (error);
1472 }
1473 #undef PROC_READ
1474 #undef PROC_WRITE
1475 
1476 /*
1477  * Stop a process because of a debugging event;
1478  * stay stopped until p->p_step is cleared
1479  * (cleared by PIOCCONT in procfs).
1480  */
1481 void
1482 stopevent(struct proc *p, unsigned int event, unsigned int val)
1483 {
1484 
1485 	PROC_LOCK_ASSERT(p, MA_OWNED);
1486 	p->p_step = 1;
1487 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1488 	    val);
1489 	do {
1490 		if (event != S_EXIT)
1491 			p->p_xsig = val;
1492 		p->p_xthread = NULL;
1493 		p->p_stype = event;	/* Which event caused the stop? */
1494 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1495 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1496 	} while (p->p_step);
1497 }
1498