xref: /freebsd/sys/kern/sys_process.c (revision 3eeb75112272ef9ef244a00bc73beef3a146856a)
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/lock.h>
40 #include <sys/mutex.h>
41 #include <sys/syscallsubr.h>
42 #include <sys/sysent.h>
43 #include <sys/sysproto.h>
44 #include <sys/pioctl.h>
45 #include <sys/priv.h>
46 #include <sys/proc.h>
47 #include <sys/vnode.h>
48 #include <sys/ptrace.h>
49 #include <sys/rwlock.h>
50 #include <sys/sx.h>
51 #include <sys/malloc.h>
52 #include <sys/signalvar.h>
53 
54 #include <machine/reg.h>
55 
56 #include <security/audit/audit.h>
57 
58 #include <vm/vm.h>
59 #include <vm/pmap.h>
60 #include <vm/vm_extern.h>
61 #include <vm/vm_map.h>
62 #include <vm/vm_kern.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_page.h>
65 #include <vm/vm_param.h>
66 
67 #ifdef COMPAT_FREEBSD32
68 #include <sys/procfs.h>
69 #include <compat/freebsd32/freebsd32_signal.h>
70 
71 struct ptrace_io_desc32 {
72 	int		piod_op;
73 	uint32_t	piod_offs;
74 	uint32_t	piod_addr;
75 	uint32_t	piod_len;
76 };
77 
78 struct ptrace_vm_entry32 {
79 	int		pve_entry;
80 	int		pve_timestamp;
81 	uint32_t	pve_start;
82 	uint32_t	pve_end;
83 	uint32_t	pve_offset;
84 	u_int		pve_prot;
85 	u_int		pve_pathlen;
86 	int32_t		pve_fileid;
87 	u_int		pve_fsid;
88 	uint32_t	pve_path;
89 };
90 #endif
91 
92 /*
93  * Functions implemented using PROC_ACTION():
94  *
95  * proc_read_regs(proc, regs)
96  *	Get the current user-visible register set from the process
97  *	and copy it into the regs structure (<machine/reg.h>).
98  *	The process is stopped at the time read_regs is called.
99  *
100  * proc_write_regs(proc, regs)
101  *	Update the current register set from the passed in regs
102  *	structure.  Take care to avoid clobbering special CPU
103  *	registers or privileged bits in the PSL.
104  *	Depending on the architecture this may have fix-up work to do,
105  *	especially if the IAR or PCW are modified.
106  *	The process is stopped at the time write_regs is called.
107  *
108  * proc_read_fpregs, proc_write_fpregs
109  *	deal with the floating point register set, otherwise as above.
110  *
111  * proc_read_dbregs, proc_write_dbregs
112  *	deal with the processor debug register set, otherwise as above.
113  *
114  * proc_sstep(proc)
115  *	Arrange for the process to trap after executing a single instruction.
116  */
117 
118 #define	PROC_ACTION(action) do {					\
119 	int error;							\
120 									\
121 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
122 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
123 		error = EIO;						\
124 	else								\
125 		error = (action);					\
126 	return (error);							\
127 } while(0)
128 
129 int
130 proc_read_regs(struct thread *td, struct reg *regs)
131 {
132 
133 	PROC_ACTION(fill_regs(td, regs));
134 }
135 
136 int
137 proc_write_regs(struct thread *td, struct reg *regs)
138 {
139 
140 	PROC_ACTION(set_regs(td, regs));
141 }
142 
143 int
144 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
145 {
146 
147 	PROC_ACTION(fill_dbregs(td, dbregs));
148 }
149 
150 int
151 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
152 {
153 
154 	PROC_ACTION(set_dbregs(td, dbregs));
155 }
156 
157 /*
158  * Ptrace doesn't support fpregs at all, and there are no security holes
159  * or translations for fpregs, so we can just copy them.
160  */
161 int
162 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
163 {
164 
165 	PROC_ACTION(fill_fpregs(td, fpregs));
166 }
167 
168 int
169 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
170 {
171 
172 	PROC_ACTION(set_fpregs(td, fpregs));
173 }
174 
175 #ifdef COMPAT_FREEBSD32
176 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
177 int
178 proc_read_regs32(struct thread *td, struct reg32 *regs32)
179 {
180 
181 	PROC_ACTION(fill_regs32(td, regs32));
182 }
183 
184 int
185 proc_write_regs32(struct thread *td, struct reg32 *regs32)
186 {
187 
188 	PROC_ACTION(set_regs32(td, regs32));
189 }
190 
191 int
192 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
193 {
194 
195 	PROC_ACTION(fill_dbregs32(td, dbregs32));
196 }
197 
198 int
199 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
200 {
201 
202 	PROC_ACTION(set_dbregs32(td, dbregs32));
203 }
204 
205 int
206 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
207 {
208 
209 	PROC_ACTION(fill_fpregs32(td, fpregs32));
210 }
211 
212 int
213 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
214 {
215 
216 	PROC_ACTION(set_fpregs32(td, fpregs32));
217 }
218 #endif
219 
220 int
221 proc_sstep(struct thread *td)
222 {
223 
224 	PROC_ACTION(ptrace_single_step(td));
225 }
226 
227 int
228 proc_rwmem(struct proc *p, struct uio *uio)
229 {
230 	vm_map_t map;
231 	vm_offset_t pageno;		/* page number */
232 	vm_prot_t reqprot;
233 	int error, fault_flags, page_offset, writing;
234 
235 	/*
236 	 * Assert that someone has locked this vmspace.  (Should be
237 	 * curthread but we can't assert that.)  This keeps the process
238 	 * from exiting out from under us until this operation completes.
239 	 */
240 	PROC_ASSERT_HELD(p);
241 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
242 
243 	/*
244 	 * The map we want...
245 	 */
246 	map = &p->p_vmspace->vm_map;
247 
248 	/*
249 	 * If we are writing, then we request vm_fault() to create a private
250 	 * copy of each page.  Since these copies will not be writeable by the
251 	 * process, we must explicity request that they be dirtied.
252 	 */
253 	writing = uio->uio_rw == UIO_WRITE;
254 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
255 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
256 
257 	/*
258 	 * Only map in one page at a time.  We don't have to, but it
259 	 * makes things easier.  This way is trivial - right?
260 	 */
261 	do {
262 		vm_offset_t uva;
263 		u_int len;
264 		vm_page_t m;
265 
266 		uva = (vm_offset_t)uio->uio_offset;
267 
268 		/*
269 		 * Get the page number of this segment.
270 		 */
271 		pageno = trunc_page(uva);
272 		page_offset = uva - pageno;
273 
274 		/*
275 		 * How many bytes to copy
276 		 */
277 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
278 
279 		/*
280 		 * Fault and hold the page on behalf of the process.
281 		 */
282 		error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
283 		if (error != KERN_SUCCESS) {
284 			if (error == KERN_RESOURCE_SHORTAGE)
285 				error = ENOMEM;
286 			else
287 				error = EFAULT;
288 			break;
289 		}
290 
291 		/*
292 		 * Now do the i/o move.
293 		 */
294 		error = uiomove_fromphys(&m, page_offset, len, uio);
295 
296 		/* Make the I-cache coherent for breakpoints. */
297 		if (writing && error == 0) {
298 			vm_map_lock_read(map);
299 			if (vm_map_check_protection(map, pageno, pageno +
300 			    PAGE_SIZE, VM_PROT_EXECUTE))
301 				vm_sync_icache(map, uva, len);
302 			vm_map_unlock_read(map);
303 		}
304 
305 		/*
306 		 * Release the page.
307 		 */
308 		vm_page_lock(m);
309 		vm_page_unhold(m);
310 		vm_page_unlock(m);
311 
312 	} while (error == 0 && uio->uio_resid > 0);
313 
314 	return (error);
315 }
316 
317 static ssize_t
318 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
319     size_t len, enum uio_rw rw)
320 {
321 	struct iovec iov;
322 	struct uio uio;
323 	ssize_t slen;
324 	int error;
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 	error = 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 		while (entry != &map->header &&
392 		    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
393 			entry = entry->next;
394 			index++;
395 		}
396 		if (entry == &map->header) {
397 			error = ENOENT;
398 			break;
399 		}
400 
401 		/* We got an entry. */
402 		pve->pve_entry = index + 1;
403 		pve->pve_timestamp = map->timestamp;
404 		pve->pve_start = entry->start;
405 		pve->pve_end = entry->end - 1;
406 		pve->pve_offset = entry->offset;
407 		pve->pve_prot = entry->protection;
408 
409 		/* Backing object's path needed? */
410 		if (pve->pve_pathlen == 0)
411 			break;
412 
413 		pathlen = pve->pve_pathlen;
414 		pve->pve_pathlen = 0;
415 
416 		obj = entry->object.vm_object;
417 		if (obj != NULL)
418 			VM_OBJECT_RLOCK(obj);
419 	} while (0);
420 
421 	vm_map_unlock_read(map);
422 
423 	pve->pve_fsid = VNOVAL;
424 	pve->pve_fileid = VNOVAL;
425 
426 	if (error == 0 && obj != NULL) {
427 		lobj = obj;
428 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
429 			if (tobj != obj)
430 				VM_OBJECT_RLOCK(tobj);
431 			if (lobj != obj)
432 				VM_OBJECT_RUNLOCK(lobj);
433 			lobj = tobj;
434 			pve->pve_offset += tobj->backing_object_offset;
435 		}
436 		vp = vm_object_vnode(lobj);
437 		if (vp != NULL)
438 			vref(vp);
439 		if (lobj != obj)
440 			VM_OBJECT_RUNLOCK(lobj);
441 		VM_OBJECT_RUNLOCK(obj);
442 
443 		if (vp != NULL) {
444 			freepath = NULL;
445 			fullpath = NULL;
446 			vn_fullpath(td, vp, &fullpath, &freepath);
447 			vn_lock(vp, LK_SHARED | LK_RETRY);
448 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
449 				pve->pve_fileid = vattr.va_fileid;
450 				pve->pve_fsid = vattr.va_fsid;
451 			}
452 			vput(vp);
453 
454 			if (fullpath != NULL) {
455 				pve->pve_pathlen = strlen(fullpath) + 1;
456 				if (pve->pve_pathlen <= pathlen) {
457 					error = copyout(fullpath, pve->pve_path,
458 					    pve->pve_pathlen);
459 				} else
460 					error = ENAMETOOLONG;
461 			}
462 			if (freepath != NULL)
463 				free(freepath, M_TEMP);
464 		}
465 	}
466 	vmspace_free(vm);
467 	if (error == 0)
468 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
469 		    p->p_pid, pve->pve_entry, pve->pve_start);
470 
471 	return (error);
472 }
473 
474 #ifdef COMPAT_FREEBSD32
475 static int
476 ptrace_vm_entry32(struct thread *td, struct proc *p,
477     struct ptrace_vm_entry32 *pve32)
478 {
479 	struct ptrace_vm_entry pve;
480 	int error;
481 
482 	pve.pve_entry = pve32->pve_entry;
483 	pve.pve_pathlen = pve32->pve_pathlen;
484 	pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
485 
486 	error = ptrace_vm_entry(td, p, &pve);
487 	if (error == 0) {
488 		pve32->pve_entry = pve.pve_entry;
489 		pve32->pve_timestamp = pve.pve_timestamp;
490 		pve32->pve_start = pve.pve_start;
491 		pve32->pve_end = pve.pve_end;
492 		pve32->pve_offset = pve.pve_offset;
493 		pve32->pve_prot = pve.pve_prot;
494 		pve32->pve_fileid = pve.pve_fileid;
495 		pve32->pve_fsid = pve.pve_fsid;
496 	}
497 
498 	pve32->pve_pathlen = pve.pve_pathlen;
499 	return (error);
500 }
501 
502 static void
503 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
504     struct ptrace_lwpinfo32 *pl32)
505 {
506 
507 	bzero(pl32, sizeof(*pl32));
508 	pl32->pl_lwpid = pl->pl_lwpid;
509 	pl32->pl_event = pl->pl_event;
510 	pl32->pl_flags = pl->pl_flags;
511 	pl32->pl_sigmask = pl->pl_sigmask;
512 	pl32->pl_siglist = pl->pl_siglist;
513 	siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
514 	strcpy(pl32->pl_tdname, pl->pl_tdname);
515 	pl32->pl_child_pid = pl->pl_child_pid;
516 	pl32->pl_syscall_code = pl->pl_syscall_code;
517 	pl32->pl_syscall_narg = pl->pl_syscall_narg;
518 }
519 #endif /* COMPAT_FREEBSD32 */
520 
521 /*
522  * Process debugging system call.
523  */
524 #ifndef _SYS_SYSPROTO_H_
525 struct ptrace_args {
526 	int	req;
527 	pid_t	pid;
528 	caddr_t	addr;
529 	int	data;
530 };
531 #endif
532 
533 #ifdef COMPAT_FREEBSD32
534 /*
535  * This CPP subterfuge is to try and reduce the number of ifdefs in
536  * the body of the code.
537  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
538  * becomes either:
539  *   copyin(uap->addr, &r.reg, sizeof r.reg);
540  * or
541  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
542  * .. except this is done at runtime.
543  */
544 #define	COPYIN(u, k, s)		wrap32 ? \
545 	copyin(u, k ## 32, s ## 32) : \
546 	copyin(u, k, s)
547 #define	COPYOUT(k, u, s)	wrap32 ? \
548 	copyout(k ## 32, u, s ## 32) : \
549 	copyout(k, u, s)
550 #else
551 #define	COPYIN(u, k, s)		copyin(u, k, s)
552 #define	COPYOUT(k, u, s)	copyout(k, u, s)
553 #endif
554 int
555 sys_ptrace(struct thread *td, struct ptrace_args *uap)
556 {
557 	/*
558 	 * XXX this obfuscation is to reduce stack usage, but the register
559 	 * structs may be too large to put on the stack anyway.
560 	 */
561 	union {
562 		struct ptrace_io_desc piod;
563 		struct ptrace_lwpinfo pl;
564 		struct ptrace_vm_entry pve;
565 		struct dbreg dbreg;
566 		struct fpreg fpreg;
567 		struct reg reg;
568 #ifdef COMPAT_FREEBSD32
569 		struct dbreg32 dbreg32;
570 		struct fpreg32 fpreg32;
571 		struct reg32 reg32;
572 		struct ptrace_io_desc32 piod32;
573 		struct ptrace_lwpinfo32 pl32;
574 		struct ptrace_vm_entry32 pve32;
575 #endif
576 		char args[nitems(td->td_sa.args) * sizeof(register_t)];
577 		int ptevents;
578 	} r;
579 	void *addr;
580 	int error = 0;
581 #ifdef COMPAT_FREEBSD32
582 	int wrap32 = 0;
583 
584 	if (SV_CURPROC_FLAG(SV_ILP32))
585 		wrap32 = 1;
586 #endif
587 	AUDIT_ARG_PID(uap->pid);
588 	AUDIT_ARG_CMD(uap->req);
589 	AUDIT_ARG_VALUE(uap->data);
590 	addr = &r;
591 	switch (uap->req) {
592 	case PT_GET_EVENT_MASK:
593 	case PT_GETREGS:
594 	case PT_GETFPREGS:
595 	case PT_GETDBREGS:
596 	case PT_LWPINFO:
597 	case PT_GET_SC_ARGS:
598 		break;
599 	case PT_SETREGS:
600 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
601 		break;
602 	case PT_SETFPREGS:
603 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
604 		break;
605 	case PT_SETDBREGS:
606 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
607 		break;
608 	case PT_SET_EVENT_MASK:
609 		if (uap->data != sizeof(r.ptevents))
610 			error = EINVAL;
611 		else
612 			error = copyin(uap->addr, &r.ptevents, uap->data);
613 		break;
614 	case PT_IO:
615 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
616 		break;
617 	case PT_VM_ENTRY:
618 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
619 		break;
620 	default:
621 		addr = uap->addr;
622 		break;
623 	}
624 	if (error)
625 		return (error);
626 
627 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
628 	if (error)
629 		return (error);
630 
631 	switch (uap->req) {
632 	case PT_VM_ENTRY:
633 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
634 		break;
635 	case PT_IO:
636 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
637 		break;
638 	case PT_GETREGS:
639 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
640 		break;
641 	case PT_GETFPREGS:
642 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
643 		break;
644 	case PT_GETDBREGS:
645 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
646 		break;
647 	case PT_GET_EVENT_MASK:
648 		/* NB: The size in uap->data is validated in kern_ptrace(). */
649 		error = copyout(&r.ptevents, uap->addr, uap->data);
650 		break;
651 	case PT_LWPINFO:
652 		/* NB: The size in uap->data is validated in kern_ptrace(). */
653 		error = copyout(&r.pl, uap->addr, uap->data);
654 		break;
655 	case PT_GET_SC_ARGS:
656 		error = copyout(r.args, uap->addr, MIN(uap->data,
657 		    sizeof(r.args)));
658 		break;
659 	}
660 
661 	return (error);
662 }
663 #undef COPYIN
664 #undef COPYOUT
665 
666 #ifdef COMPAT_FREEBSD32
667 /*
668  *   PROC_READ(regs, td2, addr);
669  * becomes either:
670  *   proc_read_regs(td2, addr);
671  * or
672  *   proc_read_regs32(td2, addr);
673  * .. except this is done at runtime.  There is an additional
674  * complication in that PROC_WRITE disallows 32 bit consumers
675  * from writing to 64 bit address space targets.
676  */
677 #define	PROC_READ(w, t, a)	wrap32 ? \
678 	proc_read_ ## w ## 32(t, a) : \
679 	proc_read_ ## w (t, a)
680 #define	PROC_WRITE(w, t, a)	wrap32 ? \
681 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
682 	proc_write_ ## w (t, a)
683 #else
684 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
685 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
686 #endif
687 
688 void
689 proc_set_traced(struct proc *p, bool stop)
690 {
691 
692 	PROC_LOCK_ASSERT(p, MA_OWNED);
693 	p->p_flag |= P_TRACED;
694 	if (stop)
695 		p->p_flag2 |= P2_PTRACE_FSTP;
696 	p->p_ptevents = PTRACE_DEFAULT;
697 	p->p_oppid = p->p_pptr->p_pid;
698 }
699 
700 int
701 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
702 {
703 	struct iovec iov;
704 	struct uio uio;
705 	struct proc *curp, *p, *pp;
706 	struct thread *td2 = NULL, *td3;
707 	struct ptrace_io_desc *piod = NULL;
708 	struct ptrace_lwpinfo *pl;
709 	int error, num, tmp;
710 	int proctree_locked = 0;
711 	lwpid_t tid = 0, *buf;
712 #ifdef COMPAT_FREEBSD32
713 	int wrap32 = 0, safe = 0;
714 	struct ptrace_io_desc32 *piod32 = NULL;
715 	struct ptrace_lwpinfo32 *pl32 = NULL;
716 	struct ptrace_lwpinfo plr;
717 #endif
718 
719 	curp = td->td_proc;
720 
721 	/* Lock proctree before locking the process. */
722 	switch (req) {
723 	case PT_TRACE_ME:
724 	case PT_ATTACH:
725 	case PT_STEP:
726 	case PT_CONTINUE:
727 	case PT_TO_SCE:
728 	case PT_TO_SCX:
729 	case PT_SYSCALL:
730 	case PT_FOLLOW_FORK:
731 	case PT_LWP_EVENTS:
732 	case PT_GET_EVENT_MASK:
733 	case PT_SET_EVENT_MASK:
734 	case PT_DETACH:
735 	case PT_GET_SC_ARGS:
736 		sx_xlock(&proctree_lock);
737 		proctree_locked = 1;
738 		break;
739 	default:
740 		break;
741 	}
742 
743 	if (req == PT_TRACE_ME) {
744 		p = td->td_proc;
745 		PROC_LOCK(p);
746 	} else {
747 		if (pid <= PID_MAX) {
748 			if ((p = pfind(pid)) == NULL) {
749 				if (proctree_locked)
750 					sx_xunlock(&proctree_lock);
751 				return (ESRCH);
752 			}
753 		} else {
754 			td2 = tdfind(pid, -1);
755 			if (td2 == NULL) {
756 				if (proctree_locked)
757 					sx_xunlock(&proctree_lock);
758 				return (ESRCH);
759 			}
760 			p = td2->td_proc;
761 			tid = pid;
762 			pid = p->p_pid;
763 		}
764 	}
765 	AUDIT_ARG_PROCESS(p);
766 
767 	if ((p->p_flag & P_WEXIT) != 0) {
768 		error = ESRCH;
769 		goto fail;
770 	}
771 	if ((error = p_cansee(td, p)) != 0)
772 		goto fail;
773 
774 	if ((error = p_candebug(td, p)) != 0)
775 		goto fail;
776 
777 	/*
778 	 * System processes can't be debugged.
779 	 */
780 	if ((p->p_flag & P_SYSTEM) != 0) {
781 		error = EINVAL;
782 		goto fail;
783 	}
784 
785 	if (tid == 0) {
786 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
787 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
788 			td2 = p->p_xthread;
789 		} else {
790 			td2 = FIRST_THREAD_IN_PROC(p);
791 		}
792 		tid = td2->td_tid;
793 	}
794 
795 #ifdef COMPAT_FREEBSD32
796 	/*
797 	 * Test if we're a 32 bit client and what the target is.
798 	 * Set the wrap controls accordingly.
799 	 */
800 	if (SV_CURPROC_FLAG(SV_ILP32)) {
801 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
802 			safe = 1;
803 		wrap32 = 1;
804 	}
805 #endif
806 	/*
807 	 * Permissions check
808 	 */
809 	switch (req) {
810 	case PT_TRACE_ME:
811 		/*
812 		 * Always legal, when there is a parent process which
813 		 * could trace us.  Otherwise, reject.
814 		 */
815 		if ((p->p_flag & P_TRACED) != 0) {
816 			error = EBUSY;
817 			goto fail;
818 		}
819 		if (p->p_pptr == initproc) {
820 			error = EPERM;
821 			goto fail;
822 		}
823 		break;
824 
825 	case PT_ATTACH:
826 		/* Self */
827 		if (p == td->td_proc) {
828 			error = EINVAL;
829 			goto fail;
830 		}
831 
832 		/* Already traced */
833 		if (p->p_flag & P_TRACED) {
834 			error = EBUSY;
835 			goto fail;
836 		}
837 
838 		/* Can't trace an ancestor if you're being traced. */
839 		if (curp->p_flag & P_TRACED) {
840 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
841 				if (pp == p) {
842 					error = EINVAL;
843 					goto fail;
844 				}
845 			}
846 		}
847 
848 
849 		/* OK */
850 		break;
851 
852 	case PT_CLEARSTEP:
853 		/* Allow thread to clear single step for itself */
854 		if (td->td_tid == tid)
855 			break;
856 
857 		/* FALLTHROUGH */
858 	default:
859 		/* not being traced... */
860 		if ((p->p_flag & P_TRACED) == 0) {
861 			error = EPERM;
862 			goto fail;
863 		}
864 
865 		/* not being traced by YOU */
866 		if (p->p_pptr != td->td_proc) {
867 			error = EBUSY;
868 			goto fail;
869 		}
870 
871 		/* not currently stopped */
872 		if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
873 		    p->p_suspcount != p->p_numthreads  ||
874 		    (p->p_flag & P_WAITED) == 0) {
875 			error = EBUSY;
876 			goto fail;
877 		}
878 
879 		/* OK */
880 		break;
881 	}
882 
883 	/* Keep this process around until we finish this request. */
884 	_PHOLD(p);
885 
886 #ifdef FIX_SSTEP
887 	/*
888 	 * Single step fixup ala procfs
889 	 */
890 	FIX_SSTEP(td2);
891 #endif
892 
893 	/*
894 	 * Actually do the requests
895 	 */
896 
897 	td->td_retval[0] = 0;
898 
899 	switch (req) {
900 	case PT_TRACE_ME:
901 		/* set my trace flag and "owner" so it can read/write me */
902 		proc_set_traced(p, false);
903 		if (p->p_flag & P_PPWAIT)
904 			p->p_flag |= P_PPTRACE;
905 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
906 		break;
907 
908 	case PT_ATTACH:
909 		/* security check done above */
910 		/*
911 		 * It would be nice if the tracing relationship was separate
912 		 * from the parent relationship but that would require
913 		 * another set of links in the proc struct or for "wait"
914 		 * to scan the entire proc table.  To make life easier,
915 		 * we just re-parent the process we're trying to trace.
916 		 * The old parent is remembered so we can put things back
917 		 * on a "detach".
918 		 */
919 		proc_set_traced(p, true);
920 		if (p->p_pptr != td->td_proc) {
921 			proc_reparent(p, td->td_proc);
922 		}
923 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
924 		    p->p_oppid);
925 
926 		sx_xunlock(&proctree_lock);
927 		proctree_locked = 0;
928 		MPASS(p->p_xthread == NULL);
929 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
930 
931 		/*
932 		 * If already stopped due to a stop signal, clear the
933 		 * existing stop before triggering a traced SIGSTOP.
934 		 */
935 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
936 			PROC_SLOCK(p);
937 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
938 			thread_unsuspend(p);
939 			PROC_SUNLOCK(p);
940 		}
941 
942 		kern_psignal(p, SIGSTOP);
943 		break;
944 
945 	case PT_CLEARSTEP:
946 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
947 		    p->p_pid);
948 		error = ptrace_clear_single_step(td2);
949 		break;
950 
951 	case PT_SETSTEP:
952 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
953 		    p->p_pid);
954 		error = ptrace_single_step(td2);
955 		break;
956 
957 	case PT_SUSPEND:
958 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
959 		    p->p_pid);
960 		td2->td_dbgflags |= TDB_SUSPEND;
961 		thread_lock(td2);
962 		td2->td_flags |= TDF_NEEDSUSPCHK;
963 		thread_unlock(td2);
964 		break;
965 
966 	case PT_RESUME:
967 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
968 		    p->p_pid);
969 		td2->td_dbgflags &= ~TDB_SUSPEND;
970 		break;
971 
972 	case PT_FOLLOW_FORK:
973 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
974 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
975 		    data ? "enabled" : "disabled");
976 		if (data)
977 			p->p_ptevents |= PTRACE_FORK;
978 		else
979 			p->p_ptevents &= ~PTRACE_FORK;
980 		break;
981 
982 	case PT_LWP_EVENTS:
983 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
984 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
985 		    data ? "enabled" : "disabled");
986 		if (data)
987 			p->p_ptevents |= PTRACE_LWP;
988 		else
989 			p->p_ptevents &= ~PTRACE_LWP;
990 		break;
991 
992 	case PT_GET_EVENT_MASK:
993 		if (data != sizeof(p->p_ptevents)) {
994 			error = EINVAL;
995 			break;
996 		}
997 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
998 		    p->p_ptevents);
999 		*(int *)addr = p->p_ptevents;
1000 		break;
1001 
1002 	case PT_SET_EVENT_MASK:
1003 		if (data != sizeof(p->p_ptevents)) {
1004 			error = EINVAL;
1005 			break;
1006 		}
1007 		tmp = *(int *)addr;
1008 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1009 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1010 			error = EINVAL;
1011 			break;
1012 		}
1013 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1014 		    p->p_pid, p->p_ptevents, tmp);
1015 		p->p_ptevents = tmp;
1016 		break;
1017 
1018 	case PT_GET_SC_ARGS:
1019 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1020 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1021 #ifdef COMPAT_FREEBSD32
1022 		    || (wrap32 && !safe)
1023 #endif
1024 		    ) {
1025 			error = EINVAL;
1026 			break;
1027 		}
1028 		bzero(addr, sizeof(td2->td_sa.args));
1029 #ifdef COMPAT_FREEBSD32
1030 		if (wrap32)
1031 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1032 				((uint32_t *)addr)[num] = (uint32_t)
1033 				    td2->td_sa.args[num];
1034 		else
1035 #endif
1036 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1037 			    sizeof(register_t));
1038 		break;
1039 
1040 	case PT_STEP:
1041 	case PT_CONTINUE:
1042 	case PT_TO_SCE:
1043 	case PT_TO_SCX:
1044 	case PT_SYSCALL:
1045 	case PT_DETACH:
1046 		/* Zero means do not send any signal */
1047 		if (data < 0 || data > _SIG_MAXSIG) {
1048 			error = EINVAL;
1049 			break;
1050 		}
1051 
1052 		switch (req) {
1053 		case PT_STEP:
1054 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1055 			    td2->td_tid, p->p_pid, data);
1056 			error = ptrace_single_step(td2);
1057 			if (error)
1058 				goto out;
1059 			break;
1060 		case PT_CONTINUE:
1061 		case PT_TO_SCE:
1062 		case PT_TO_SCX:
1063 		case PT_SYSCALL:
1064 			if (addr != (void *)1) {
1065 				error = ptrace_set_pc(td2,
1066 				    (u_long)(uintfptr_t)addr);
1067 				if (error)
1068 					goto out;
1069 			}
1070 			switch (req) {
1071 			case PT_TO_SCE:
1072 				p->p_ptevents |= PTRACE_SCE;
1073 				CTR4(KTR_PTRACE,
1074 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1075 				    p->p_pid, p->p_ptevents,
1076 				    (u_long)(uintfptr_t)addr, data);
1077 				break;
1078 			case PT_TO_SCX:
1079 				p->p_ptevents |= PTRACE_SCX;
1080 				CTR4(KTR_PTRACE,
1081 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1082 				    p->p_pid, p->p_ptevents,
1083 				    (u_long)(uintfptr_t)addr, data);
1084 				break;
1085 			case PT_SYSCALL:
1086 				p->p_ptevents |= PTRACE_SYSCALL;
1087 				CTR4(KTR_PTRACE,
1088 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1089 				    p->p_pid, p->p_ptevents,
1090 				    (u_long)(uintfptr_t)addr, data);
1091 				break;
1092 			case PT_CONTINUE:
1093 				CTR3(KTR_PTRACE,
1094 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1095 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1096 				break;
1097 			}
1098 			break;
1099 		case PT_DETACH:
1100 			/*
1101 			 * Reset the process parent.
1102 			 *
1103 			 * NB: This clears P_TRACED before reparenting
1104 			 * a detached process back to its original
1105 			 * parent.  Otherwise the debugee will be set
1106 			 * as an orphan of the debugger.
1107 			 */
1108 			p->p_flag &= ~(P_TRACED | P_WAITED);
1109 			if (p->p_oppid != p->p_pptr->p_pid) {
1110 				PROC_LOCK(p->p_pptr);
1111 				sigqueue_take(p->p_ksi);
1112 				PROC_UNLOCK(p->p_pptr);
1113 
1114 				pp = proc_realparent(p);
1115 				proc_reparent(p, pp);
1116 				if (pp == initproc)
1117 					p->p_sigparent = SIGCHLD;
1118 				CTR3(KTR_PTRACE,
1119 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1120 				    p->p_pid, pp->p_pid, data);
1121 			} else
1122 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1123 				    p->p_pid, data);
1124 			p->p_oppid = 0;
1125 			p->p_ptevents = 0;
1126 			FOREACH_THREAD_IN_PROC(p, td3) {
1127 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1128 					sigqueue_delete(&td3->td_sigqueue,
1129 					    SIGSTOP);
1130 				}
1131 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1132 				    TDB_SUSPEND);
1133 			}
1134 
1135 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1136 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1137 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1138 			}
1139 
1140 			/* should we send SIGCHLD? */
1141 			/* childproc_continued(p); */
1142 			break;
1143 		}
1144 
1145 		sx_xunlock(&proctree_lock);
1146 		proctree_locked = 0;
1147 
1148 	sendsig:
1149 		MPASS(proctree_locked == 0);
1150 
1151 		/*
1152 		 * Clear the pending event for the thread that just
1153 		 * reported its event (p_xthread).  This may not be
1154 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1155 		 * the debugger is resuming a different thread.
1156 		 *
1157 		 * Deliver any pending signal via the reporting thread.
1158 		 */
1159 		MPASS(p->p_xthread != NULL);
1160 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1161 		p->p_xthread->td_xsig = data;
1162 		p->p_xthread = NULL;
1163 		p->p_xsig = data;
1164 
1165 		/*
1166 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1167 		 * always works immediately, even if another thread is
1168 		 * unsuspended first and attempts to handle a
1169 		 * different signal or if the POSIX.1b style signal
1170 		 * queue cannot accommodate any new signals.
1171 		 */
1172 		if (data == SIGKILL)
1173 			p->p_flag |= P_WKILLED;
1174 
1175 		/*
1176 		 * Unsuspend all threads.  To leave a thread
1177 		 * suspended, use PT_SUSPEND to suspend it before
1178 		 * continuing the process.
1179 		 */
1180 		PROC_SLOCK(p);
1181 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1182 		thread_unsuspend(p);
1183 		PROC_SUNLOCK(p);
1184 		break;
1185 
1186 	case PT_WRITE_I:
1187 	case PT_WRITE_D:
1188 		td2->td_dbgflags |= TDB_USERWR;
1189 		PROC_UNLOCK(p);
1190 		error = 0;
1191 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1192 		    sizeof(int)) != sizeof(int))
1193 			error = ENOMEM;
1194 		else
1195 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1196 			    p->p_pid, addr, data);
1197 		PROC_LOCK(p);
1198 		break;
1199 
1200 	case PT_READ_I:
1201 	case PT_READ_D:
1202 		PROC_UNLOCK(p);
1203 		error = tmp = 0;
1204 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1205 		    sizeof(int)) != sizeof(int))
1206 			error = ENOMEM;
1207 		else
1208 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1209 			    p->p_pid, addr, tmp);
1210 		td->td_retval[0] = tmp;
1211 		PROC_LOCK(p);
1212 		break;
1213 
1214 	case PT_IO:
1215 #ifdef COMPAT_FREEBSD32
1216 		if (wrap32) {
1217 			piod32 = addr;
1218 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1219 			iov.iov_len = piod32->piod_len;
1220 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1221 			uio.uio_resid = piod32->piod_len;
1222 		} else
1223 #endif
1224 		{
1225 			piod = addr;
1226 			iov.iov_base = piod->piod_addr;
1227 			iov.iov_len = piod->piod_len;
1228 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1229 			uio.uio_resid = piod->piod_len;
1230 		}
1231 		uio.uio_iov = &iov;
1232 		uio.uio_iovcnt = 1;
1233 		uio.uio_segflg = UIO_USERSPACE;
1234 		uio.uio_td = td;
1235 #ifdef COMPAT_FREEBSD32
1236 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1237 #else
1238 		tmp = piod->piod_op;
1239 #endif
1240 		switch (tmp) {
1241 		case PIOD_READ_D:
1242 		case PIOD_READ_I:
1243 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1244 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1245 			uio.uio_rw = UIO_READ;
1246 			break;
1247 		case PIOD_WRITE_D:
1248 		case PIOD_WRITE_I:
1249 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1250 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1251 			td2->td_dbgflags |= TDB_USERWR;
1252 			uio.uio_rw = UIO_WRITE;
1253 			break;
1254 		default:
1255 			error = EINVAL;
1256 			goto out;
1257 		}
1258 		PROC_UNLOCK(p);
1259 		error = proc_rwmem(p, &uio);
1260 #ifdef COMPAT_FREEBSD32
1261 		if (wrap32)
1262 			piod32->piod_len -= uio.uio_resid;
1263 		else
1264 #endif
1265 			piod->piod_len -= uio.uio_resid;
1266 		PROC_LOCK(p);
1267 		break;
1268 
1269 	case PT_KILL:
1270 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1271 		data = SIGKILL;
1272 		goto sendsig;	/* in PT_CONTINUE above */
1273 
1274 	case PT_SETREGS:
1275 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1276 		    p->p_pid);
1277 		td2->td_dbgflags |= TDB_USERWR;
1278 		error = PROC_WRITE(regs, td2, addr);
1279 		break;
1280 
1281 	case PT_GETREGS:
1282 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1283 		    p->p_pid);
1284 		error = PROC_READ(regs, td2, addr);
1285 		break;
1286 
1287 	case PT_SETFPREGS:
1288 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1289 		    p->p_pid);
1290 		td2->td_dbgflags |= TDB_USERWR;
1291 		error = PROC_WRITE(fpregs, td2, addr);
1292 		break;
1293 
1294 	case PT_GETFPREGS:
1295 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1296 		    p->p_pid);
1297 		error = PROC_READ(fpregs, td2, addr);
1298 		break;
1299 
1300 	case PT_SETDBREGS:
1301 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1302 		    p->p_pid);
1303 		td2->td_dbgflags |= TDB_USERWR;
1304 		error = PROC_WRITE(dbregs, td2, addr);
1305 		break;
1306 
1307 	case PT_GETDBREGS:
1308 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1309 		    p->p_pid);
1310 		error = PROC_READ(dbregs, td2, addr);
1311 		break;
1312 
1313 	case PT_LWPINFO:
1314 		if (data <= 0 ||
1315 #ifdef COMPAT_FREEBSD32
1316 		    (!wrap32 && data > sizeof(*pl)) ||
1317 		    (wrap32 && data > sizeof(*pl32))) {
1318 #else
1319 		    data > sizeof(*pl)) {
1320 #endif
1321 			error = EINVAL;
1322 			break;
1323 		}
1324 #ifdef COMPAT_FREEBSD32
1325 		if (wrap32) {
1326 			pl = &plr;
1327 			pl32 = addr;
1328 		} else
1329 #endif
1330 		pl = addr;
1331 		bzero(pl, sizeof(*pl));
1332 		pl->pl_lwpid = td2->td_tid;
1333 		pl->pl_event = PL_EVENT_NONE;
1334 		pl->pl_flags = 0;
1335 		if (td2->td_dbgflags & TDB_XSIG) {
1336 			pl->pl_event = PL_EVENT_SIGNAL;
1337 			if (td2->td_si.si_signo != 0 &&
1338 #ifdef COMPAT_FREEBSD32
1339 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1340 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1341 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1342 			    pl_siginfo) + sizeof(struct siginfo32)))
1343 #else
1344 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1345 			    + sizeof(pl->pl_siginfo)
1346 #endif
1347 			){
1348 				pl->pl_flags |= PL_FLAG_SI;
1349 				pl->pl_siginfo = td2->td_si;
1350 			}
1351 		}
1352 		if (td2->td_dbgflags & TDB_SCE)
1353 			pl->pl_flags |= PL_FLAG_SCE;
1354 		else if (td2->td_dbgflags & TDB_SCX)
1355 			pl->pl_flags |= PL_FLAG_SCX;
1356 		if (td2->td_dbgflags & TDB_EXEC)
1357 			pl->pl_flags |= PL_FLAG_EXEC;
1358 		if (td2->td_dbgflags & TDB_FORK) {
1359 			pl->pl_flags |= PL_FLAG_FORKED;
1360 			pl->pl_child_pid = td2->td_dbg_forked;
1361 			if (td2->td_dbgflags & TDB_VFORK)
1362 				pl->pl_flags |= PL_FLAG_VFORKED;
1363 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1364 		    TDB_VFORK)
1365 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1366 		if (td2->td_dbgflags & TDB_CHILD)
1367 			pl->pl_flags |= PL_FLAG_CHILD;
1368 		if (td2->td_dbgflags & TDB_BORN)
1369 			pl->pl_flags |= PL_FLAG_BORN;
1370 		if (td2->td_dbgflags & TDB_EXIT)
1371 			pl->pl_flags |= PL_FLAG_EXITED;
1372 		pl->pl_sigmask = td2->td_sigmask;
1373 		pl->pl_siglist = td2->td_siglist;
1374 		strcpy(pl->pl_tdname, td2->td_name);
1375 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1376 			pl->pl_syscall_code = td2->td_sa.code;
1377 			pl->pl_syscall_narg = td2->td_sa.narg;
1378 		} else {
1379 			pl->pl_syscall_code = 0;
1380 			pl->pl_syscall_narg = 0;
1381 		}
1382 #ifdef COMPAT_FREEBSD32
1383 		if (wrap32)
1384 			ptrace_lwpinfo_to32(pl, pl32);
1385 #endif
1386 		CTR6(KTR_PTRACE,
1387     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1388 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1389 		    pl->pl_child_pid, pl->pl_syscall_code);
1390 		break;
1391 
1392 	case PT_GETNUMLWPS:
1393 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1394 		    p->p_numthreads);
1395 		td->td_retval[0] = p->p_numthreads;
1396 		break;
1397 
1398 	case PT_GETLWPLIST:
1399 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1400 		    p->p_pid, data, p->p_numthreads);
1401 		if (data <= 0) {
1402 			error = EINVAL;
1403 			break;
1404 		}
1405 		num = imin(p->p_numthreads, data);
1406 		PROC_UNLOCK(p);
1407 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1408 		tmp = 0;
1409 		PROC_LOCK(p);
1410 		FOREACH_THREAD_IN_PROC(p, td2) {
1411 			if (tmp >= num)
1412 				break;
1413 			buf[tmp++] = td2->td_tid;
1414 		}
1415 		PROC_UNLOCK(p);
1416 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1417 		free(buf, M_TEMP);
1418 		if (!error)
1419 			td->td_retval[0] = tmp;
1420 		PROC_LOCK(p);
1421 		break;
1422 
1423 	case PT_VM_TIMESTAMP:
1424 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1425 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1426 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1427 		break;
1428 
1429 	case PT_VM_ENTRY:
1430 		PROC_UNLOCK(p);
1431 #ifdef COMPAT_FREEBSD32
1432 		if (wrap32)
1433 			error = ptrace_vm_entry32(td, p, addr);
1434 		else
1435 #endif
1436 		error = ptrace_vm_entry(td, p, addr);
1437 		PROC_LOCK(p);
1438 		break;
1439 
1440 	default:
1441 #ifdef __HAVE_PTRACE_MACHDEP
1442 		if (req >= PT_FIRSTMACH) {
1443 			PROC_UNLOCK(p);
1444 			error = cpu_ptrace(td2, req, addr, data);
1445 			PROC_LOCK(p);
1446 		} else
1447 #endif
1448 			/* Unknown request. */
1449 			error = EINVAL;
1450 		break;
1451 	}
1452 
1453 out:
1454 	/* Drop our hold on this process now that the request has completed. */
1455 	_PRELE(p);
1456 fail:
1457 	PROC_UNLOCK(p);
1458 	if (proctree_locked)
1459 		sx_xunlock(&proctree_lock);
1460 	return (error);
1461 }
1462 #undef PROC_READ
1463 #undef PROC_WRITE
1464 
1465 /*
1466  * Stop a process because of a debugging event;
1467  * stay stopped until p->p_step is cleared
1468  * (cleared by PIOCCONT in procfs).
1469  */
1470 void
1471 stopevent(struct proc *p, unsigned int event, unsigned int val)
1472 {
1473 
1474 	PROC_LOCK_ASSERT(p, MA_OWNED);
1475 	p->p_step = 1;
1476 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1477 	    val);
1478 	do {
1479 		if (event != S_EXIT)
1480 			p->p_xsig = val;
1481 		p->p_xthread = NULL;
1482 		p->p_stype = event;	/* Which event caused the stop? */
1483 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1484 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1485 	} while (p->p_step);
1486 }
1487