xref: /freebsd/sys/kern/sys_process.c (revision 01b01229540bfa1a250973da7c8a1a3d84853ca5)
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 		if (vm_page_unwire(m, PQ_ACTIVE) && m->object == NULL)
311 			vm_page_free(m);
312 		vm_page_unlock(m);
313 
314 	} while (error == 0 && uio->uio_resid > 0);
315 
316 	return (error);
317 }
318 
319 static ssize_t
320 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
321     size_t len, enum uio_rw rw)
322 {
323 	struct iovec iov;
324 	struct uio uio;
325 	ssize_t slen;
326 
327 	MPASS(len < SSIZE_MAX);
328 	slen = (ssize_t)len;
329 
330 	iov.iov_base = (caddr_t)buf;
331 	iov.iov_len = len;
332 	uio.uio_iov = &iov;
333 	uio.uio_iovcnt = 1;
334 	uio.uio_offset = va;
335 	uio.uio_resid = slen;
336 	uio.uio_segflg = UIO_SYSSPACE;
337 	uio.uio_rw = rw;
338 	uio.uio_td = td;
339 	proc_rwmem(p, &uio);
340 	if (uio.uio_resid == slen)
341 		return (-1);
342 	return (slen - uio.uio_resid);
343 }
344 
345 ssize_t
346 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
347     size_t len)
348 {
349 
350 	return (proc_iop(td, p, va, buf, len, UIO_READ));
351 }
352 
353 ssize_t
354 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
355     size_t len)
356 {
357 
358 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
359 }
360 
361 static int
362 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
363 {
364 	struct vattr vattr;
365 	vm_map_t map;
366 	vm_map_entry_t entry;
367 	vm_object_t obj, tobj, lobj;
368 	struct vmspace *vm;
369 	struct vnode *vp;
370 	char *freepath, *fullpath;
371 	u_int pathlen;
372 	int error, index;
373 
374 	error = 0;
375 	obj = NULL;
376 
377 	vm = vmspace_acquire_ref(p);
378 	map = &vm->vm_map;
379 	vm_map_lock_read(map);
380 
381 	do {
382 		entry = map->header.next;
383 		index = 0;
384 		while (index < pve->pve_entry && entry != &map->header) {
385 			entry = entry->next;
386 			index++;
387 		}
388 		if (index != pve->pve_entry) {
389 			error = EINVAL;
390 			break;
391 		}
392 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
393 		    ("Submap in map header"));
394 		while ((entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
395 			entry = entry->next;
396 			index++;
397 		}
398 		if (entry == &map->header) {
399 			error = ENOENT;
400 			break;
401 		}
402 
403 		/* We got an entry. */
404 		pve->pve_entry = index + 1;
405 		pve->pve_timestamp = map->timestamp;
406 		pve->pve_start = entry->start;
407 		pve->pve_end = entry->end - 1;
408 		pve->pve_offset = entry->offset;
409 		pve->pve_prot = entry->protection;
410 
411 		/* Backing object's path needed? */
412 		if (pve->pve_pathlen == 0)
413 			break;
414 
415 		pathlen = pve->pve_pathlen;
416 		pve->pve_pathlen = 0;
417 
418 		obj = entry->object.vm_object;
419 		if (obj != NULL)
420 			VM_OBJECT_RLOCK(obj);
421 	} while (0);
422 
423 	vm_map_unlock_read(map);
424 
425 	pve->pve_fsid = VNOVAL;
426 	pve->pve_fileid = VNOVAL;
427 
428 	if (error == 0 && obj != NULL) {
429 		lobj = obj;
430 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
431 			if (tobj != obj)
432 				VM_OBJECT_RLOCK(tobj);
433 			if (lobj != obj)
434 				VM_OBJECT_RUNLOCK(lobj);
435 			lobj = tobj;
436 			pve->pve_offset += tobj->backing_object_offset;
437 		}
438 		vp = vm_object_vnode(lobj);
439 		if (vp != NULL)
440 			vref(vp);
441 		if (lobj != obj)
442 			VM_OBJECT_RUNLOCK(lobj);
443 		VM_OBJECT_RUNLOCK(obj);
444 
445 		if (vp != NULL) {
446 			freepath = NULL;
447 			fullpath = NULL;
448 			vn_fullpath(td, vp, &fullpath, &freepath);
449 			vn_lock(vp, LK_SHARED | LK_RETRY);
450 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
451 				pve->pve_fileid = vattr.va_fileid;
452 				pve->pve_fsid = vattr.va_fsid;
453 			}
454 			vput(vp);
455 
456 			if (fullpath != NULL) {
457 				pve->pve_pathlen = strlen(fullpath) + 1;
458 				if (pve->pve_pathlen <= pathlen) {
459 					error = copyout(fullpath, pve->pve_path,
460 					    pve->pve_pathlen);
461 				} else
462 					error = ENAMETOOLONG;
463 			}
464 			if (freepath != NULL)
465 				free(freepath, M_TEMP);
466 		}
467 	}
468 	vmspace_free(vm);
469 	if (error == 0)
470 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
471 		    p->p_pid, pve->pve_entry, pve->pve_start);
472 
473 	return (error);
474 }
475 
476 #ifdef COMPAT_FREEBSD32
477 static int
478 ptrace_vm_entry32(struct thread *td, struct proc *p,
479     struct ptrace_vm_entry32 *pve32)
480 {
481 	struct ptrace_vm_entry pve;
482 	int error;
483 
484 	pve.pve_entry = pve32->pve_entry;
485 	pve.pve_pathlen = pve32->pve_pathlen;
486 	pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
487 
488 	error = ptrace_vm_entry(td, p, &pve);
489 	if (error == 0) {
490 		pve32->pve_entry = pve.pve_entry;
491 		pve32->pve_timestamp = pve.pve_timestamp;
492 		pve32->pve_start = pve.pve_start;
493 		pve32->pve_end = pve.pve_end;
494 		pve32->pve_offset = pve.pve_offset;
495 		pve32->pve_prot = pve.pve_prot;
496 		pve32->pve_fileid = pve.pve_fileid;
497 		pve32->pve_fsid = pve.pve_fsid;
498 	}
499 
500 	pve32->pve_pathlen = pve.pve_pathlen;
501 	return (error);
502 }
503 
504 static void
505 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
506     struct ptrace_lwpinfo32 *pl32)
507 {
508 
509 	bzero(pl32, sizeof(*pl32));
510 	pl32->pl_lwpid = pl->pl_lwpid;
511 	pl32->pl_event = pl->pl_event;
512 	pl32->pl_flags = pl->pl_flags;
513 	pl32->pl_sigmask = pl->pl_sigmask;
514 	pl32->pl_siglist = pl->pl_siglist;
515 	siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
516 	strcpy(pl32->pl_tdname, pl->pl_tdname);
517 	pl32->pl_child_pid = pl->pl_child_pid;
518 	pl32->pl_syscall_code = pl->pl_syscall_code;
519 	pl32->pl_syscall_narg = pl->pl_syscall_narg;
520 }
521 #endif /* COMPAT_FREEBSD32 */
522 
523 /*
524  * Process debugging system call.
525  */
526 #ifndef _SYS_SYSPROTO_H_
527 struct ptrace_args {
528 	int	req;
529 	pid_t	pid;
530 	caddr_t	addr;
531 	int	data;
532 };
533 #endif
534 
535 #ifdef COMPAT_FREEBSD32
536 /*
537  * This CPP subterfuge is to try and reduce the number of ifdefs in
538  * the body of the code.
539  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
540  * becomes either:
541  *   copyin(uap->addr, &r.reg, sizeof r.reg);
542  * or
543  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
544  * .. except this is done at runtime.
545  */
546 #define	BZERO(a, s)		wrap32 ? \
547 	bzero(a ## 32, s ## 32) : \
548 	bzero(a, s)
549 #define	COPYIN(u, k, s)		wrap32 ? \
550 	copyin(u, k ## 32, s ## 32) : \
551 	copyin(u, k, s)
552 #define	COPYOUT(k, u, s)	wrap32 ? \
553 	copyout(k ## 32, u, s ## 32) : \
554 	copyout(k, u, s)
555 #else
556 #define	BZERO(a, s)		bzero(a, s)
557 #define	COPYIN(u, k, s)		copyin(u, k, s)
558 #define	COPYOUT(k, u, s)	copyout(k, u, s)
559 #endif
560 int
561 sys_ptrace(struct thread *td, struct ptrace_args *uap)
562 {
563 	/*
564 	 * XXX this obfuscation is to reduce stack usage, but the register
565 	 * structs may be too large to put on the stack anyway.
566 	 */
567 	union {
568 		struct ptrace_io_desc piod;
569 		struct ptrace_lwpinfo pl;
570 		struct ptrace_vm_entry pve;
571 		struct dbreg dbreg;
572 		struct fpreg fpreg;
573 		struct reg reg;
574 #ifdef COMPAT_FREEBSD32
575 		struct dbreg32 dbreg32;
576 		struct fpreg32 fpreg32;
577 		struct reg32 reg32;
578 		struct ptrace_io_desc32 piod32;
579 		struct ptrace_lwpinfo32 pl32;
580 		struct ptrace_vm_entry32 pve32;
581 #endif
582 		char args[sizeof(td->td_sa.args)];
583 		int ptevents;
584 	} r;
585 	void *addr;
586 	int error = 0;
587 #ifdef COMPAT_FREEBSD32
588 	int wrap32 = 0;
589 
590 	if (SV_CURPROC_FLAG(SV_ILP32))
591 		wrap32 = 1;
592 #endif
593 	AUDIT_ARG_PID(uap->pid);
594 	AUDIT_ARG_CMD(uap->req);
595 	AUDIT_ARG_VALUE(uap->data);
596 	addr = &r;
597 	switch (uap->req) {
598 	case PT_GET_EVENT_MASK:
599 	case PT_LWPINFO:
600 	case PT_GET_SC_ARGS:
601 		break;
602 	case PT_GETREGS:
603 		BZERO(&r.reg, sizeof r.reg);
604 		break;
605 	case PT_GETFPREGS:
606 		BZERO(&r.fpreg, sizeof r.fpreg);
607 		break;
608 	case PT_GETDBREGS:
609 		BZERO(&r.dbreg, sizeof r.dbreg);
610 		break;
611 	case PT_SETREGS:
612 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
613 		break;
614 	case PT_SETFPREGS:
615 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
616 		break;
617 	case PT_SETDBREGS:
618 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
619 		break;
620 	case PT_SET_EVENT_MASK:
621 		if (uap->data != sizeof(r.ptevents))
622 			error = EINVAL;
623 		else
624 			error = copyin(uap->addr, &r.ptevents, uap->data);
625 		break;
626 	case PT_IO:
627 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
628 		break;
629 	case PT_VM_ENTRY:
630 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
631 		break;
632 	default:
633 		addr = uap->addr;
634 		break;
635 	}
636 	if (error)
637 		return (error);
638 
639 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
640 	if (error)
641 		return (error);
642 
643 	switch (uap->req) {
644 	case PT_VM_ENTRY:
645 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
646 		break;
647 	case PT_IO:
648 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
649 		break;
650 	case PT_GETREGS:
651 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
652 		break;
653 	case PT_GETFPREGS:
654 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
655 		break;
656 	case PT_GETDBREGS:
657 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
658 		break;
659 	case PT_GET_EVENT_MASK:
660 		/* NB: The size in uap->data is validated in kern_ptrace(). */
661 		error = copyout(&r.ptevents, uap->addr, uap->data);
662 		break;
663 	case PT_LWPINFO:
664 		/* NB: The size in uap->data is validated in kern_ptrace(). */
665 		error = copyout(&r.pl, uap->addr, uap->data);
666 		break;
667 	case PT_GET_SC_ARGS:
668 		error = copyout(r.args, uap->addr, MIN(uap->data,
669 		    sizeof(r.args)));
670 		break;
671 	}
672 
673 	return (error);
674 }
675 #undef COPYIN
676 #undef COPYOUT
677 #undef BZERO
678 
679 #ifdef COMPAT_FREEBSD32
680 /*
681  *   PROC_READ(regs, td2, addr);
682  * becomes either:
683  *   proc_read_regs(td2, addr);
684  * or
685  *   proc_read_regs32(td2, addr);
686  * .. except this is done at runtime.  There is an additional
687  * complication in that PROC_WRITE disallows 32 bit consumers
688  * from writing to 64 bit address space targets.
689  */
690 #define	PROC_READ(w, t, a)	wrap32 ? \
691 	proc_read_ ## w ## 32(t, a) : \
692 	proc_read_ ## w (t, a)
693 #define	PROC_WRITE(w, t, a)	wrap32 ? \
694 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
695 	proc_write_ ## w (t, a)
696 #else
697 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
698 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
699 #endif
700 
701 void
702 proc_set_traced(struct proc *p, bool stop)
703 {
704 
705 	sx_assert(&proctree_lock, SX_XLOCKED);
706 	PROC_LOCK_ASSERT(p, MA_OWNED);
707 	p->p_flag |= P_TRACED;
708 	if (stop)
709 		p->p_flag2 |= P2_PTRACE_FSTP;
710 	p->p_ptevents = PTRACE_DEFAULT;
711 }
712 
713 int
714 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
715 {
716 	struct iovec iov;
717 	struct uio uio;
718 	struct proc *curp, *p, *pp;
719 	struct thread *td2 = NULL, *td3;
720 	struct ptrace_io_desc *piod = NULL;
721 	struct ptrace_lwpinfo *pl;
722 	int error, num, tmp;
723 	int proctree_locked = 0;
724 	lwpid_t tid = 0, *buf;
725 #ifdef COMPAT_FREEBSD32
726 	int wrap32 = 0, safe = 0;
727 	struct ptrace_io_desc32 *piod32 = NULL;
728 	struct ptrace_lwpinfo32 *pl32 = NULL;
729 	struct ptrace_lwpinfo plr;
730 #endif
731 
732 	curp = td->td_proc;
733 
734 	/* Lock proctree before locking the process. */
735 	switch (req) {
736 	case PT_TRACE_ME:
737 	case PT_ATTACH:
738 	case PT_STEP:
739 	case PT_CONTINUE:
740 	case PT_TO_SCE:
741 	case PT_TO_SCX:
742 	case PT_SYSCALL:
743 	case PT_FOLLOW_FORK:
744 	case PT_LWP_EVENTS:
745 	case PT_GET_EVENT_MASK:
746 	case PT_SET_EVENT_MASK:
747 	case PT_DETACH:
748 	case PT_GET_SC_ARGS:
749 		sx_xlock(&proctree_lock);
750 		proctree_locked = 1;
751 		break;
752 	default:
753 		break;
754 	}
755 
756 	if (req == PT_TRACE_ME) {
757 		p = td->td_proc;
758 		PROC_LOCK(p);
759 	} else {
760 		if (pid <= PID_MAX) {
761 			if ((p = pfind(pid)) == NULL) {
762 				if (proctree_locked)
763 					sx_xunlock(&proctree_lock);
764 				return (ESRCH);
765 			}
766 		} else {
767 			td2 = tdfind(pid, -1);
768 			if (td2 == NULL) {
769 				if (proctree_locked)
770 					sx_xunlock(&proctree_lock);
771 				return (ESRCH);
772 			}
773 			p = td2->td_proc;
774 			tid = pid;
775 			pid = p->p_pid;
776 		}
777 	}
778 	AUDIT_ARG_PROCESS(p);
779 
780 	if ((p->p_flag & P_WEXIT) != 0) {
781 		error = ESRCH;
782 		goto fail;
783 	}
784 	if ((error = p_cansee(td, p)) != 0)
785 		goto fail;
786 
787 	if ((error = p_candebug(td, p)) != 0)
788 		goto fail;
789 
790 	/*
791 	 * System processes can't be debugged.
792 	 */
793 	if ((p->p_flag & P_SYSTEM) != 0) {
794 		error = EINVAL;
795 		goto fail;
796 	}
797 
798 	if (tid == 0) {
799 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
800 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
801 			td2 = p->p_xthread;
802 		} else {
803 			td2 = FIRST_THREAD_IN_PROC(p);
804 		}
805 		tid = td2->td_tid;
806 	}
807 
808 #ifdef COMPAT_FREEBSD32
809 	/*
810 	 * Test if we're a 32 bit client and what the target is.
811 	 * Set the wrap controls accordingly.
812 	 */
813 	if (SV_CURPROC_FLAG(SV_ILP32)) {
814 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
815 			safe = 1;
816 		wrap32 = 1;
817 	}
818 #endif
819 	/*
820 	 * Permissions check
821 	 */
822 	switch (req) {
823 	case PT_TRACE_ME:
824 		/*
825 		 * Always legal, when there is a parent process which
826 		 * could trace us.  Otherwise, reject.
827 		 */
828 		if ((p->p_flag & P_TRACED) != 0) {
829 			error = EBUSY;
830 			goto fail;
831 		}
832 		if (p->p_pptr == initproc) {
833 			error = EPERM;
834 			goto fail;
835 		}
836 		break;
837 
838 	case PT_ATTACH:
839 		/* Self */
840 		if (p == td->td_proc) {
841 			error = EINVAL;
842 			goto fail;
843 		}
844 
845 		/* Already traced */
846 		if (p->p_flag & P_TRACED) {
847 			error = EBUSY;
848 			goto fail;
849 		}
850 
851 		/* Can't trace an ancestor if you're being traced. */
852 		if (curp->p_flag & P_TRACED) {
853 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
854 				if (pp == p) {
855 					error = EINVAL;
856 					goto fail;
857 				}
858 			}
859 		}
860 
861 
862 		/* OK */
863 		break;
864 
865 	case PT_CLEARSTEP:
866 		/* Allow thread to clear single step for itself */
867 		if (td->td_tid == tid)
868 			break;
869 
870 		/* FALLTHROUGH */
871 	default:
872 		/* not being traced... */
873 		if ((p->p_flag & P_TRACED) == 0) {
874 			error = EPERM;
875 			goto fail;
876 		}
877 
878 		/* not being traced by YOU */
879 		if (p->p_pptr != td->td_proc) {
880 			error = EBUSY;
881 			goto fail;
882 		}
883 
884 		/* not currently stopped */
885 		if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
886 		    p->p_suspcount != p->p_numthreads  ||
887 		    (p->p_flag & P_WAITED) == 0) {
888 			error = EBUSY;
889 			goto fail;
890 		}
891 
892 		/* OK */
893 		break;
894 	}
895 
896 	/* Keep this process around until we finish this request. */
897 	_PHOLD(p);
898 
899 #ifdef FIX_SSTEP
900 	/*
901 	 * Single step fixup ala procfs
902 	 */
903 	FIX_SSTEP(td2);
904 #endif
905 
906 	/*
907 	 * Actually do the requests
908 	 */
909 
910 	td->td_retval[0] = 0;
911 
912 	switch (req) {
913 	case PT_TRACE_ME:
914 		/* set my trace flag and "owner" so it can read/write me */
915 		proc_set_traced(p, false);
916 		if (p->p_flag & P_PPWAIT)
917 			p->p_flag |= P_PPTRACE;
918 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
919 		break;
920 
921 	case PT_ATTACH:
922 		/* security check done above */
923 		/*
924 		 * It would be nice if the tracing relationship was separate
925 		 * from the parent relationship but that would require
926 		 * another set of links in the proc struct or for "wait"
927 		 * to scan the entire proc table.  To make life easier,
928 		 * we just re-parent the process we're trying to trace.
929 		 * The old parent is remembered so we can put things back
930 		 * on a "detach".
931 		 */
932 		proc_set_traced(p, true);
933 		if (p->p_pptr != td->td_proc) {
934 			proc_reparent(p, td->td_proc, false);
935 		}
936 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
937 		    p->p_oppid);
938 
939 		sx_xunlock(&proctree_lock);
940 		proctree_locked = 0;
941 		MPASS(p->p_xthread == NULL);
942 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
943 
944 		/*
945 		 * If already stopped due to a stop signal, clear the
946 		 * existing stop before triggering a traced SIGSTOP.
947 		 */
948 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
949 			PROC_SLOCK(p);
950 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
951 			thread_unsuspend(p);
952 			PROC_SUNLOCK(p);
953 		}
954 
955 		kern_psignal(p, SIGSTOP);
956 		break;
957 
958 	case PT_CLEARSTEP:
959 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
960 		    p->p_pid);
961 		error = ptrace_clear_single_step(td2);
962 		break;
963 
964 	case PT_SETSTEP:
965 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
966 		    p->p_pid);
967 		error = ptrace_single_step(td2);
968 		break;
969 
970 	case PT_SUSPEND:
971 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
972 		    p->p_pid);
973 		td2->td_dbgflags |= TDB_SUSPEND;
974 		thread_lock(td2);
975 		td2->td_flags |= TDF_NEEDSUSPCHK;
976 		thread_unlock(td2);
977 		break;
978 
979 	case PT_RESUME:
980 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
981 		    p->p_pid);
982 		td2->td_dbgflags &= ~TDB_SUSPEND;
983 		break;
984 
985 	case PT_FOLLOW_FORK:
986 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
987 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
988 		    data ? "enabled" : "disabled");
989 		if (data)
990 			p->p_ptevents |= PTRACE_FORK;
991 		else
992 			p->p_ptevents &= ~PTRACE_FORK;
993 		break;
994 
995 	case PT_LWP_EVENTS:
996 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
997 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
998 		    data ? "enabled" : "disabled");
999 		if (data)
1000 			p->p_ptevents |= PTRACE_LWP;
1001 		else
1002 			p->p_ptevents &= ~PTRACE_LWP;
1003 		break;
1004 
1005 	case PT_GET_EVENT_MASK:
1006 		if (data != sizeof(p->p_ptevents)) {
1007 			error = EINVAL;
1008 			break;
1009 		}
1010 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1011 		    p->p_ptevents);
1012 		*(int *)addr = p->p_ptevents;
1013 		break;
1014 
1015 	case PT_SET_EVENT_MASK:
1016 		if (data != sizeof(p->p_ptevents)) {
1017 			error = EINVAL;
1018 			break;
1019 		}
1020 		tmp = *(int *)addr;
1021 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1022 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1023 			error = EINVAL;
1024 			break;
1025 		}
1026 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1027 		    p->p_pid, p->p_ptevents, tmp);
1028 		p->p_ptevents = tmp;
1029 		break;
1030 
1031 	case PT_GET_SC_ARGS:
1032 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1033 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1034 #ifdef COMPAT_FREEBSD32
1035 		    || (wrap32 && !safe)
1036 #endif
1037 		    ) {
1038 			error = EINVAL;
1039 			break;
1040 		}
1041 		bzero(addr, sizeof(td2->td_sa.args));
1042 #ifdef COMPAT_FREEBSD32
1043 		if (wrap32)
1044 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1045 				((uint32_t *)addr)[num] = (uint32_t)
1046 				    td2->td_sa.args[num];
1047 		else
1048 #endif
1049 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1050 			    sizeof(register_t));
1051 		break;
1052 
1053 	case PT_STEP:
1054 	case PT_CONTINUE:
1055 	case PT_TO_SCE:
1056 	case PT_TO_SCX:
1057 	case PT_SYSCALL:
1058 	case PT_DETACH:
1059 		/* Zero means do not send any signal */
1060 		if (data < 0 || data > _SIG_MAXSIG) {
1061 			error = EINVAL;
1062 			break;
1063 		}
1064 
1065 		switch (req) {
1066 		case PT_STEP:
1067 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1068 			    td2->td_tid, p->p_pid, data);
1069 			error = ptrace_single_step(td2);
1070 			if (error)
1071 				goto out;
1072 			break;
1073 		case PT_CONTINUE:
1074 		case PT_TO_SCE:
1075 		case PT_TO_SCX:
1076 		case PT_SYSCALL:
1077 			if (addr != (void *)1) {
1078 				error = ptrace_set_pc(td2,
1079 				    (u_long)(uintfptr_t)addr);
1080 				if (error)
1081 					goto out;
1082 			}
1083 			switch (req) {
1084 			case PT_TO_SCE:
1085 				p->p_ptevents |= PTRACE_SCE;
1086 				CTR4(KTR_PTRACE,
1087 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1088 				    p->p_pid, p->p_ptevents,
1089 				    (u_long)(uintfptr_t)addr, data);
1090 				break;
1091 			case PT_TO_SCX:
1092 				p->p_ptevents |= PTRACE_SCX;
1093 				CTR4(KTR_PTRACE,
1094 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1095 				    p->p_pid, p->p_ptevents,
1096 				    (u_long)(uintfptr_t)addr, data);
1097 				break;
1098 			case PT_SYSCALL:
1099 				p->p_ptevents |= PTRACE_SYSCALL;
1100 				CTR4(KTR_PTRACE,
1101 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1102 				    p->p_pid, p->p_ptevents,
1103 				    (u_long)(uintfptr_t)addr, data);
1104 				break;
1105 			case PT_CONTINUE:
1106 				CTR3(KTR_PTRACE,
1107 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1108 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1109 				break;
1110 			}
1111 			break;
1112 		case PT_DETACH:
1113 			/*
1114 			 * Reset the process parent.
1115 			 *
1116 			 * NB: This clears P_TRACED before reparenting
1117 			 * a detached process back to its original
1118 			 * parent.  Otherwise the debugee will be set
1119 			 * as an orphan of the debugger.
1120 			 */
1121 			p->p_flag &= ~(P_TRACED | P_WAITED);
1122 			if (p->p_oppid != p->p_pptr->p_pid) {
1123 				PROC_LOCK(p->p_pptr);
1124 				sigqueue_take(p->p_ksi);
1125 				PROC_UNLOCK(p->p_pptr);
1126 
1127 				pp = proc_realparent(p);
1128 				proc_reparent(p, pp, false);
1129 				if (pp == initproc)
1130 					p->p_sigparent = SIGCHLD;
1131 				CTR3(KTR_PTRACE,
1132 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1133 				    p->p_pid, pp->p_pid, data);
1134 			} else
1135 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1136 				    p->p_pid, data);
1137 			p->p_ptevents = 0;
1138 			FOREACH_THREAD_IN_PROC(p, td3) {
1139 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1140 					sigqueue_delete(&td3->td_sigqueue,
1141 					    SIGSTOP);
1142 				}
1143 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1144 				    TDB_SUSPEND);
1145 			}
1146 
1147 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1148 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1149 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1150 			}
1151 
1152 			/* should we send SIGCHLD? */
1153 			/* childproc_continued(p); */
1154 			break;
1155 		}
1156 
1157 		sx_xunlock(&proctree_lock);
1158 		proctree_locked = 0;
1159 
1160 	sendsig:
1161 		MPASS(proctree_locked == 0);
1162 
1163 		/*
1164 		 * Clear the pending event for the thread that just
1165 		 * reported its event (p_xthread).  This may not be
1166 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1167 		 * the debugger is resuming a different thread.
1168 		 *
1169 		 * Deliver any pending signal via the reporting thread.
1170 		 */
1171 		MPASS(p->p_xthread != NULL);
1172 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1173 		p->p_xthread->td_xsig = data;
1174 		p->p_xthread = NULL;
1175 		p->p_xsig = data;
1176 
1177 		/*
1178 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1179 		 * always works immediately, even if another thread is
1180 		 * unsuspended first and attempts to handle a
1181 		 * different signal or if the POSIX.1b style signal
1182 		 * queue cannot accommodate any new signals.
1183 		 */
1184 		if (data == SIGKILL)
1185 			proc_wkilled(p);
1186 
1187 		/*
1188 		 * Unsuspend all threads.  To leave a thread
1189 		 * suspended, use PT_SUSPEND to suspend it before
1190 		 * continuing the process.
1191 		 */
1192 		PROC_SLOCK(p);
1193 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1194 		thread_unsuspend(p);
1195 		PROC_SUNLOCK(p);
1196 		break;
1197 
1198 	case PT_WRITE_I:
1199 	case PT_WRITE_D:
1200 		td2->td_dbgflags |= TDB_USERWR;
1201 		PROC_UNLOCK(p);
1202 		error = 0;
1203 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1204 		    sizeof(int)) != sizeof(int))
1205 			error = ENOMEM;
1206 		else
1207 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1208 			    p->p_pid, addr, data);
1209 		PROC_LOCK(p);
1210 		break;
1211 
1212 	case PT_READ_I:
1213 	case PT_READ_D:
1214 		PROC_UNLOCK(p);
1215 		error = tmp = 0;
1216 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1217 		    sizeof(int)) != sizeof(int))
1218 			error = ENOMEM;
1219 		else
1220 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1221 			    p->p_pid, addr, tmp);
1222 		td->td_retval[0] = tmp;
1223 		PROC_LOCK(p);
1224 		break;
1225 
1226 	case PT_IO:
1227 #ifdef COMPAT_FREEBSD32
1228 		if (wrap32) {
1229 			piod32 = addr;
1230 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1231 			iov.iov_len = piod32->piod_len;
1232 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1233 			uio.uio_resid = piod32->piod_len;
1234 		} else
1235 #endif
1236 		{
1237 			piod = addr;
1238 			iov.iov_base = piod->piod_addr;
1239 			iov.iov_len = piod->piod_len;
1240 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1241 			uio.uio_resid = piod->piod_len;
1242 		}
1243 		uio.uio_iov = &iov;
1244 		uio.uio_iovcnt = 1;
1245 		uio.uio_segflg = UIO_USERSPACE;
1246 		uio.uio_td = td;
1247 #ifdef COMPAT_FREEBSD32
1248 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1249 #else
1250 		tmp = piod->piod_op;
1251 #endif
1252 		switch (tmp) {
1253 		case PIOD_READ_D:
1254 		case PIOD_READ_I:
1255 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1256 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1257 			uio.uio_rw = UIO_READ;
1258 			break;
1259 		case PIOD_WRITE_D:
1260 		case PIOD_WRITE_I:
1261 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1262 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1263 			td2->td_dbgflags |= TDB_USERWR;
1264 			uio.uio_rw = UIO_WRITE;
1265 			break;
1266 		default:
1267 			error = EINVAL;
1268 			goto out;
1269 		}
1270 		PROC_UNLOCK(p);
1271 		error = proc_rwmem(p, &uio);
1272 #ifdef COMPAT_FREEBSD32
1273 		if (wrap32)
1274 			piod32->piod_len -= uio.uio_resid;
1275 		else
1276 #endif
1277 			piod->piod_len -= uio.uio_resid;
1278 		PROC_LOCK(p);
1279 		break;
1280 
1281 	case PT_KILL:
1282 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1283 		data = SIGKILL;
1284 		goto sendsig;	/* in PT_CONTINUE above */
1285 
1286 	case PT_SETREGS:
1287 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1288 		    p->p_pid);
1289 		td2->td_dbgflags |= TDB_USERWR;
1290 		error = PROC_WRITE(regs, td2, addr);
1291 		break;
1292 
1293 	case PT_GETREGS:
1294 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1295 		    p->p_pid);
1296 		error = PROC_READ(regs, td2, addr);
1297 		break;
1298 
1299 	case PT_SETFPREGS:
1300 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1301 		    p->p_pid);
1302 		td2->td_dbgflags |= TDB_USERWR;
1303 		error = PROC_WRITE(fpregs, td2, addr);
1304 		break;
1305 
1306 	case PT_GETFPREGS:
1307 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1308 		    p->p_pid);
1309 		error = PROC_READ(fpregs, td2, addr);
1310 		break;
1311 
1312 	case PT_SETDBREGS:
1313 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1314 		    p->p_pid);
1315 		td2->td_dbgflags |= TDB_USERWR;
1316 		error = PROC_WRITE(dbregs, td2, addr);
1317 		break;
1318 
1319 	case PT_GETDBREGS:
1320 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1321 		    p->p_pid);
1322 		error = PROC_READ(dbregs, td2, addr);
1323 		break;
1324 
1325 	case PT_LWPINFO:
1326 		if (data <= 0 ||
1327 #ifdef COMPAT_FREEBSD32
1328 		    (!wrap32 && data > sizeof(*pl)) ||
1329 		    (wrap32 && data > sizeof(*pl32))) {
1330 #else
1331 		    data > sizeof(*pl)) {
1332 #endif
1333 			error = EINVAL;
1334 			break;
1335 		}
1336 #ifdef COMPAT_FREEBSD32
1337 		if (wrap32) {
1338 			pl = &plr;
1339 			pl32 = addr;
1340 		} else
1341 #endif
1342 		pl = addr;
1343 		bzero(pl, sizeof(*pl));
1344 		pl->pl_lwpid = td2->td_tid;
1345 		pl->pl_event = PL_EVENT_NONE;
1346 		pl->pl_flags = 0;
1347 		if (td2->td_dbgflags & TDB_XSIG) {
1348 			pl->pl_event = PL_EVENT_SIGNAL;
1349 			if (td2->td_si.si_signo != 0 &&
1350 #ifdef COMPAT_FREEBSD32
1351 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1352 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1353 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1354 			    pl_siginfo) + sizeof(struct siginfo32)))
1355 #else
1356 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1357 			    + sizeof(pl->pl_siginfo)
1358 #endif
1359 			){
1360 				pl->pl_flags |= PL_FLAG_SI;
1361 				pl->pl_siginfo = td2->td_si;
1362 			}
1363 		}
1364 		if (td2->td_dbgflags & TDB_SCE)
1365 			pl->pl_flags |= PL_FLAG_SCE;
1366 		else if (td2->td_dbgflags & TDB_SCX)
1367 			pl->pl_flags |= PL_FLAG_SCX;
1368 		if (td2->td_dbgflags & TDB_EXEC)
1369 			pl->pl_flags |= PL_FLAG_EXEC;
1370 		if (td2->td_dbgflags & TDB_FORK) {
1371 			pl->pl_flags |= PL_FLAG_FORKED;
1372 			pl->pl_child_pid = td2->td_dbg_forked;
1373 			if (td2->td_dbgflags & TDB_VFORK)
1374 				pl->pl_flags |= PL_FLAG_VFORKED;
1375 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1376 		    TDB_VFORK)
1377 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1378 		if (td2->td_dbgflags & TDB_CHILD)
1379 			pl->pl_flags |= PL_FLAG_CHILD;
1380 		if (td2->td_dbgflags & TDB_BORN)
1381 			pl->pl_flags |= PL_FLAG_BORN;
1382 		if (td2->td_dbgflags & TDB_EXIT)
1383 			pl->pl_flags |= PL_FLAG_EXITED;
1384 		pl->pl_sigmask = td2->td_sigmask;
1385 		pl->pl_siglist = td2->td_siglist;
1386 		strcpy(pl->pl_tdname, td2->td_name);
1387 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1388 			pl->pl_syscall_code = td2->td_sa.code;
1389 			pl->pl_syscall_narg = td2->td_sa.narg;
1390 		} else {
1391 			pl->pl_syscall_code = 0;
1392 			pl->pl_syscall_narg = 0;
1393 		}
1394 #ifdef COMPAT_FREEBSD32
1395 		if (wrap32)
1396 			ptrace_lwpinfo_to32(pl, pl32);
1397 #endif
1398 		CTR6(KTR_PTRACE,
1399     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1400 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1401 		    pl->pl_child_pid, pl->pl_syscall_code);
1402 		break;
1403 
1404 	case PT_GETNUMLWPS:
1405 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1406 		    p->p_numthreads);
1407 		td->td_retval[0] = p->p_numthreads;
1408 		break;
1409 
1410 	case PT_GETLWPLIST:
1411 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1412 		    p->p_pid, data, p->p_numthreads);
1413 		if (data <= 0) {
1414 			error = EINVAL;
1415 			break;
1416 		}
1417 		num = imin(p->p_numthreads, data);
1418 		PROC_UNLOCK(p);
1419 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1420 		tmp = 0;
1421 		PROC_LOCK(p);
1422 		FOREACH_THREAD_IN_PROC(p, td2) {
1423 			if (tmp >= num)
1424 				break;
1425 			buf[tmp++] = td2->td_tid;
1426 		}
1427 		PROC_UNLOCK(p);
1428 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1429 		free(buf, M_TEMP);
1430 		if (!error)
1431 			td->td_retval[0] = tmp;
1432 		PROC_LOCK(p);
1433 		break;
1434 
1435 	case PT_VM_TIMESTAMP:
1436 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1437 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1438 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1439 		break;
1440 
1441 	case PT_VM_ENTRY:
1442 		PROC_UNLOCK(p);
1443 #ifdef COMPAT_FREEBSD32
1444 		if (wrap32)
1445 			error = ptrace_vm_entry32(td, p, addr);
1446 		else
1447 #endif
1448 		error = ptrace_vm_entry(td, p, addr);
1449 		PROC_LOCK(p);
1450 		break;
1451 
1452 	default:
1453 #ifdef __HAVE_PTRACE_MACHDEP
1454 		if (req >= PT_FIRSTMACH) {
1455 			PROC_UNLOCK(p);
1456 			error = cpu_ptrace(td2, req, addr, data);
1457 			PROC_LOCK(p);
1458 		} else
1459 #endif
1460 			/* Unknown request. */
1461 			error = EINVAL;
1462 		break;
1463 	}
1464 
1465 out:
1466 	/* Drop our hold on this process now that the request has completed. */
1467 	_PRELE(p);
1468 fail:
1469 	PROC_UNLOCK(p);
1470 	if (proctree_locked)
1471 		sx_xunlock(&proctree_lock);
1472 	return (error);
1473 }
1474 #undef PROC_READ
1475 #undef PROC_WRITE
1476 
1477 /*
1478  * Stop a process because of a debugging event;
1479  * stay stopped until p->p_step is cleared
1480  * (cleared by PIOCCONT in procfs).
1481  */
1482 void
1483 stopevent(struct proc *p, unsigned int event, unsigned int val)
1484 {
1485 
1486 	PROC_LOCK_ASSERT(p, MA_OWNED);
1487 	p->p_step = 1;
1488 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1489 	    val);
1490 	do {
1491 		if (event != S_EXIT)
1492 			p->p_xsig = val;
1493 		p->p_xthread = NULL;
1494 		p->p_stype = event;	/* Which event caused the stop? */
1495 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1496 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1497 	} while (p->p_step);
1498 }
1499