xref: /freebsd/sys/kern/sys_process.c (revision fe2494903422ba3b924eba82cb63a6a9188fad7a)
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 
325 	MPASS(len < SSIZE_MAX);
326 	slen = (ssize_t)len;
327 
328 	iov.iov_base = (caddr_t)buf;
329 	iov.iov_len = len;
330 	uio.uio_iov = &iov;
331 	uio.uio_iovcnt = 1;
332 	uio.uio_offset = va;
333 	uio.uio_resid = slen;
334 	uio.uio_segflg = UIO_SYSSPACE;
335 	uio.uio_rw = rw;
336 	uio.uio_td = td;
337 	proc_rwmem(p, &uio);
338 	if (uio.uio_resid == slen)
339 		return (-1);
340 	return (slen - uio.uio_resid);
341 }
342 
343 ssize_t
344 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
345     size_t len)
346 {
347 
348 	return (proc_iop(td, p, va, buf, len, UIO_READ));
349 }
350 
351 ssize_t
352 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
353     size_t len)
354 {
355 
356 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
357 }
358 
359 static int
360 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
361 {
362 	struct vattr vattr;
363 	vm_map_t map;
364 	vm_map_entry_t entry;
365 	vm_object_t obj, tobj, lobj;
366 	struct vmspace *vm;
367 	struct vnode *vp;
368 	char *freepath, *fullpath;
369 	u_int pathlen;
370 	int error, index;
371 
372 	error = 0;
373 	obj = NULL;
374 
375 	vm = vmspace_acquire_ref(p);
376 	map = &vm->vm_map;
377 	vm_map_lock_read(map);
378 
379 	do {
380 		entry = map->header.next;
381 		index = 0;
382 		while (index < pve->pve_entry && entry != &map->header) {
383 			entry = entry->next;
384 			index++;
385 		}
386 		if (index != pve->pve_entry) {
387 			error = EINVAL;
388 			break;
389 		}
390 		KASSERT((map->header.eflags & MAP_ENTRY_IS_SUB_MAP) == 0,
391 		    ("Submap in map header"));
392 		while ((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 	sx_assert(&proctree_lock, SX_XLOCKED);
693 	PROC_LOCK_ASSERT(p, MA_OWNED);
694 	p->p_flag |= P_TRACED;
695 	if (stop)
696 		p->p_flag2 |= P2_PTRACE_FSTP;
697 	p->p_ptevents = PTRACE_DEFAULT;
698 	p->p_oppid = p->p_pptr->p_pid;
699 }
700 
701 int
702 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
703 {
704 	struct iovec iov;
705 	struct uio uio;
706 	struct proc *curp, *p, *pp;
707 	struct thread *td2 = NULL, *td3;
708 	struct ptrace_io_desc *piod = NULL;
709 	struct ptrace_lwpinfo *pl;
710 	int error, num, tmp;
711 	int proctree_locked = 0;
712 	lwpid_t tid = 0, *buf;
713 #ifdef COMPAT_FREEBSD32
714 	int wrap32 = 0, safe = 0;
715 	struct ptrace_io_desc32 *piod32 = NULL;
716 	struct ptrace_lwpinfo32 *pl32 = NULL;
717 	struct ptrace_lwpinfo plr;
718 #endif
719 
720 	curp = td->td_proc;
721 
722 	/* Lock proctree before locking the process. */
723 	switch (req) {
724 	case PT_TRACE_ME:
725 	case PT_ATTACH:
726 	case PT_STEP:
727 	case PT_CONTINUE:
728 	case PT_TO_SCE:
729 	case PT_TO_SCX:
730 	case PT_SYSCALL:
731 	case PT_FOLLOW_FORK:
732 	case PT_LWP_EVENTS:
733 	case PT_GET_EVENT_MASK:
734 	case PT_SET_EVENT_MASK:
735 	case PT_DETACH:
736 	case PT_GET_SC_ARGS:
737 		sx_xlock(&proctree_lock);
738 		proctree_locked = 1;
739 		break;
740 	default:
741 		break;
742 	}
743 
744 	if (req == PT_TRACE_ME) {
745 		p = td->td_proc;
746 		PROC_LOCK(p);
747 	} else {
748 		if (pid <= PID_MAX) {
749 			if ((p = pfind(pid)) == NULL) {
750 				if (proctree_locked)
751 					sx_xunlock(&proctree_lock);
752 				return (ESRCH);
753 			}
754 		} else {
755 			td2 = tdfind(pid, -1);
756 			if (td2 == NULL) {
757 				if (proctree_locked)
758 					sx_xunlock(&proctree_lock);
759 				return (ESRCH);
760 			}
761 			p = td2->td_proc;
762 			tid = pid;
763 			pid = p->p_pid;
764 		}
765 	}
766 	AUDIT_ARG_PROCESS(p);
767 
768 	if ((p->p_flag & P_WEXIT) != 0) {
769 		error = ESRCH;
770 		goto fail;
771 	}
772 	if ((error = p_cansee(td, p)) != 0)
773 		goto fail;
774 
775 	if ((error = p_candebug(td, p)) != 0)
776 		goto fail;
777 
778 	/*
779 	 * System processes can't be debugged.
780 	 */
781 	if ((p->p_flag & P_SYSTEM) != 0) {
782 		error = EINVAL;
783 		goto fail;
784 	}
785 
786 	if (tid == 0) {
787 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
788 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
789 			td2 = p->p_xthread;
790 		} else {
791 			td2 = FIRST_THREAD_IN_PROC(p);
792 		}
793 		tid = td2->td_tid;
794 	}
795 
796 #ifdef COMPAT_FREEBSD32
797 	/*
798 	 * Test if we're a 32 bit client and what the target is.
799 	 * Set the wrap controls accordingly.
800 	 */
801 	if (SV_CURPROC_FLAG(SV_ILP32)) {
802 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
803 			safe = 1;
804 		wrap32 = 1;
805 	}
806 #endif
807 	/*
808 	 * Permissions check
809 	 */
810 	switch (req) {
811 	case PT_TRACE_ME:
812 		/*
813 		 * Always legal, when there is a parent process which
814 		 * could trace us.  Otherwise, reject.
815 		 */
816 		if ((p->p_flag & P_TRACED) != 0) {
817 			error = EBUSY;
818 			goto fail;
819 		}
820 		if (p->p_pptr == initproc) {
821 			error = EPERM;
822 			goto fail;
823 		}
824 		break;
825 
826 	case PT_ATTACH:
827 		/* Self */
828 		if (p == td->td_proc) {
829 			error = EINVAL;
830 			goto fail;
831 		}
832 
833 		/* Already traced */
834 		if (p->p_flag & P_TRACED) {
835 			error = EBUSY;
836 			goto fail;
837 		}
838 
839 		/* Can't trace an ancestor if you're being traced. */
840 		if (curp->p_flag & P_TRACED) {
841 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
842 				if (pp == p) {
843 					error = EINVAL;
844 					goto fail;
845 				}
846 			}
847 		}
848 
849 
850 		/* OK */
851 		break;
852 
853 	case PT_CLEARSTEP:
854 		/* Allow thread to clear single step for itself */
855 		if (td->td_tid == tid)
856 			break;
857 
858 		/* FALLTHROUGH */
859 	default:
860 		/* not being traced... */
861 		if ((p->p_flag & P_TRACED) == 0) {
862 			error = EPERM;
863 			goto fail;
864 		}
865 
866 		/* not being traced by YOU */
867 		if (p->p_pptr != td->td_proc) {
868 			error = EBUSY;
869 			goto fail;
870 		}
871 
872 		/* not currently stopped */
873 		if ((p->p_flag & P_STOPPED_TRACE) == 0 ||
874 		    p->p_suspcount != p->p_numthreads  ||
875 		    (p->p_flag & P_WAITED) == 0) {
876 			error = EBUSY;
877 			goto fail;
878 		}
879 
880 		/* OK */
881 		break;
882 	}
883 
884 	/* Keep this process around until we finish this request. */
885 	_PHOLD(p);
886 
887 #ifdef FIX_SSTEP
888 	/*
889 	 * Single step fixup ala procfs
890 	 */
891 	FIX_SSTEP(td2);
892 #endif
893 
894 	/*
895 	 * Actually do the requests
896 	 */
897 
898 	td->td_retval[0] = 0;
899 
900 	switch (req) {
901 	case PT_TRACE_ME:
902 		/* set my trace flag and "owner" so it can read/write me */
903 		proc_set_traced(p, false);
904 		if (p->p_flag & P_PPWAIT)
905 			p->p_flag |= P_PPTRACE;
906 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
907 		break;
908 
909 	case PT_ATTACH:
910 		/* security check done above */
911 		/*
912 		 * It would be nice if the tracing relationship was separate
913 		 * from the parent relationship but that would require
914 		 * another set of links in the proc struct or for "wait"
915 		 * to scan the entire proc table.  To make life easier,
916 		 * we just re-parent the process we're trying to trace.
917 		 * The old parent is remembered so we can put things back
918 		 * on a "detach".
919 		 */
920 		proc_set_traced(p, true);
921 		if (p->p_pptr != td->td_proc) {
922 			proc_reparent(p, td->td_proc);
923 		}
924 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
925 		    p->p_oppid);
926 
927 		sx_xunlock(&proctree_lock);
928 		proctree_locked = 0;
929 		MPASS(p->p_xthread == NULL);
930 		MPASS((p->p_flag & P_STOPPED_TRACE) == 0);
931 
932 		/*
933 		 * If already stopped due to a stop signal, clear the
934 		 * existing stop before triggering a traced SIGSTOP.
935 		 */
936 		if ((p->p_flag & P_STOPPED_SIG) != 0) {
937 			PROC_SLOCK(p);
938 			p->p_flag &= ~(P_STOPPED_SIG | P_WAITED);
939 			thread_unsuspend(p);
940 			PROC_SUNLOCK(p);
941 		}
942 
943 		kern_psignal(p, SIGSTOP);
944 		break;
945 
946 	case PT_CLEARSTEP:
947 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
948 		    p->p_pid);
949 		error = ptrace_clear_single_step(td2);
950 		break;
951 
952 	case PT_SETSTEP:
953 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
954 		    p->p_pid);
955 		error = ptrace_single_step(td2);
956 		break;
957 
958 	case PT_SUSPEND:
959 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
960 		    p->p_pid);
961 		td2->td_dbgflags |= TDB_SUSPEND;
962 		thread_lock(td2);
963 		td2->td_flags |= TDF_NEEDSUSPCHK;
964 		thread_unlock(td2);
965 		break;
966 
967 	case PT_RESUME:
968 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
969 		    p->p_pid);
970 		td2->td_dbgflags &= ~TDB_SUSPEND;
971 		break;
972 
973 	case PT_FOLLOW_FORK:
974 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
975 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
976 		    data ? "enabled" : "disabled");
977 		if (data)
978 			p->p_ptevents |= PTRACE_FORK;
979 		else
980 			p->p_ptevents &= ~PTRACE_FORK;
981 		break;
982 
983 	case PT_LWP_EVENTS:
984 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
985 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
986 		    data ? "enabled" : "disabled");
987 		if (data)
988 			p->p_ptevents |= PTRACE_LWP;
989 		else
990 			p->p_ptevents &= ~PTRACE_LWP;
991 		break;
992 
993 	case PT_GET_EVENT_MASK:
994 		if (data != sizeof(p->p_ptevents)) {
995 			error = EINVAL;
996 			break;
997 		}
998 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
999 		    p->p_ptevents);
1000 		*(int *)addr = p->p_ptevents;
1001 		break;
1002 
1003 	case PT_SET_EVENT_MASK:
1004 		if (data != sizeof(p->p_ptevents)) {
1005 			error = EINVAL;
1006 			break;
1007 		}
1008 		tmp = *(int *)addr;
1009 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1010 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1011 			error = EINVAL;
1012 			break;
1013 		}
1014 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1015 		    p->p_pid, p->p_ptevents, tmp);
1016 		p->p_ptevents = tmp;
1017 		break;
1018 
1019 	case PT_GET_SC_ARGS:
1020 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1021 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1022 #ifdef COMPAT_FREEBSD32
1023 		    || (wrap32 && !safe)
1024 #endif
1025 		    ) {
1026 			error = EINVAL;
1027 			break;
1028 		}
1029 		bzero(addr, sizeof(td2->td_sa.args));
1030 #ifdef COMPAT_FREEBSD32
1031 		if (wrap32)
1032 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1033 				((uint32_t *)addr)[num] = (uint32_t)
1034 				    td2->td_sa.args[num];
1035 		else
1036 #endif
1037 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1038 			    sizeof(register_t));
1039 		break;
1040 
1041 	case PT_STEP:
1042 	case PT_CONTINUE:
1043 	case PT_TO_SCE:
1044 	case PT_TO_SCX:
1045 	case PT_SYSCALL:
1046 	case PT_DETACH:
1047 		/* Zero means do not send any signal */
1048 		if (data < 0 || data > _SIG_MAXSIG) {
1049 			error = EINVAL;
1050 			break;
1051 		}
1052 
1053 		switch (req) {
1054 		case PT_STEP:
1055 			CTR3(KTR_PTRACE, "PT_STEP: tid %d (pid %d), sig = %d",
1056 			    td2->td_tid, p->p_pid, data);
1057 			error = ptrace_single_step(td2);
1058 			if (error)
1059 				goto out;
1060 			break;
1061 		case PT_CONTINUE:
1062 		case PT_TO_SCE:
1063 		case PT_TO_SCX:
1064 		case PT_SYSCALL:
1065 			if (addr != (void *)1) {
1066 				error = ptrace_set_pc(td2,
1067 				    (u_long)(uintfptr_t)addr);
1068 				if (error)
1069 					goto out;
1070 			}
1071 			switch (req) {
1072 			case PT_TO_SCE:
1073 				p->p_ptevents |= PTRACE_SCE;
1074 				CTR4(KTR_PTRACE,
1075 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1076 				    p->p_pid, p->p_ptevents,
1077 				    (u_long)(uintfptr_t)addr, data);
1078 				break;
1079 			case PT_TO_SCX:
1080 				p->p_ptevents |= PTRACE_SCX;
1081 				CTR4(KTR_PTRACE,
1082 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1083 				    p->p_pid, p->p_ptevents,
1084 				    (u_long)(uintfptr_t)addr, data);
1085 				break;
1086 			case PT_SYSCALL:
1087 				p->p_ptevents |= PTRACE_SYSCALL;
1088 				CTR4(KTR_PTRACE,
1089 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1090 				    p->p_pid, p->p_ptevents,
1091 				    (u_long)(uintfptr_t)addr, data);
1092 				break;
1093 			case PT_CONTINUE:
1094 				CTR3(KTR_PTRACE,
1095 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1096 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1097 				break;
1098 			}
1099 			break;
1100 		case PT_DETACH:
1101 			/*
1102 			 * Reset the process parent.
1103 			 *
1104 			 * NB: This clears P_TRACED before reparenting
1105 			 * a detached process back to its original
1106 			 * parent.  Otherwise the debugee will be set
1107 			 * as an orphan of the debugger.
1108 			 */
1109 			p->p_flag &= ~(P_TRACED | P_WAITED);
1110 			if (p->p_oppid != p->p_pptr->p_pid) {
1111 				PROC_LOCK(p->p_pptr);
1112 				sigqueue_take(p->p_ksi);
1113 				PROC_UNLOCK(p->p_pptr);
1114 
1115 				pp = proc_realparent(p);
1116 				proc_reparent(p, pp);
1117 				if (pp == initproc)
1118 					p->p_sigparent = SIGCHLD;
1119 				CTR3(KTR_PTRACE,
1120 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1121 				    p->p_pid, pp->p_pid, data);
1122 			} else
1123 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1124 				    p->p_pid, data);
1125 			p->p_oppid = 0;
1126 			p->p_ptevents = 0;
1127 			FOREACH_THREAD_IN_PROC(p, td3) {
1128 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1129 					sigqueue_delete(&td3->td_sigqueue,
1130 					    SIGSTOP);
1131 				}
1132 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP |
1133 				    TDB_SUSPEND);
1134 			}
1135 
1136 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1137 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1138 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1139 			}
1140 
1141 			/* should we send SIGCHLD? */
1142 			/* childproc_continued(p); */
1143 			break;
1144 		}
1145 
1146 		sx_xunlock(&proctree_lock);
1147 		proctree_locked = 0;
1148 
1149 	sendsig:
1150 		MPASS(proctree_locked == 0);
1151 
1152 		/*
1153 		 * Clear the pending event for the thread that just
1154 		 * reported its event (p_xthread).  This may not be
1155 		 * the thread passed to PT_CONTINUE, PT_STEP, etc. if
1156 		 * the debugger is resuming a different thread.
1157 		 *
1158 		 * Deliver any pending signal via the reporting thread.
1159 		 */
1160 		MPASS(p->p_xthread != NULL);
1161 		p->p_xthread->td_dbgflags &= ~TDB_XSIG;
1162 		p->p_xthread->td_xsig = data;
1163 		p->p_xthread = NULL;
1164 		p->p_xsig = data;
1165 
1166 		/*
1167 		 * P_WKILLED is insurance that a PT_KILL/SIGKILL
1168 		 * always works immediately, even if another thread is
1169 		 * unsuspended first and attempts to handle a
1170 		 * different signal or if the POSIX.1b style signal
1171 		 * queue cannot accommodate any new signals.
1172 		 */
1173 		if (data == SIGKILL)
1174 			proc_wkilled(p);
1175 
1176 		/*
1177 		 * Unsuspend all threads.  To leave a thread
1178 		 * suspended, use PT_SUSPEND to suspend it before
1179 		 * continuing the process.
1180 		 */
1181 		PROC_SLOCK(p);
1182 		p->p_flag &= ~(P_STOPPED_TRACE | P_STOPPED_SIG | P_WAITED);
1183 		thread_unsuspend(p);
1184 		PROC_SUNLOCK(p);
1185 		break;
1186 
1187 	case PT_WRITE_I:
1188 	case PT_WRITE_D:
1189 		td2->td_dbgflags |= TDB_USERWR;
1190 		PROC_UNLOCK(p);
1191 		error = 0;
1192 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1193 		    sizeof(int)) != sizeof(int))
1194 			error = ENOMEM;
1195 		else
1196 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1197 			    p->p_pid, addr, data);
1198 		PROC_LOCK(p);
1199 		break;
1200 
1201 	case PT_READ_I:
1202 	case PT_READ_D:
1203 		PROC_UNLOCK(p);
1204 		error = tmp = 0;
1205 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1206 		    sizeof(int)) != sizeof(int))
1207 			error = ENOMEM;
1208 		else
1209 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1210 			    p->p_pid, addr, tmp);
1211 		td->td_retval[0] = tmp;
1212 		PROC_LOCK(p);
1213 		break;
1214 
1215 	case PT_IO:
1216 #ifdef COMPAT_FREEBSD32
1217 		if (wrap32) {
1218 			piod32 = addr;
1219 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1220 			iov.iov_len = piod32->piod_len;
1221 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1222 			uio.uio_resid = piod32->piod_len;
1223 		} else
1224 #endif
1225 		{
1226 			piod = addr;
1227 			iov.iov_base = piod->piod_addr;
1228 			iov.iov_len = piod->piod_len;
1229 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1230 			uio.uio_resid = piod->piod_len;
1231 		}
1232 		uio.uio_iov = &iov;
1233 		uio.uio_iovcnt = 1;
1234 		uio.uio_segflg = UIO_USERSPACE;
1235 		uio.uio_td = td;
1236 #ifdef COMPAT_FREEBSD32
1237 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1238 #else
1239 		tmp = piod->piod_op;
1240 #endif
1241 		switch (tmp) {
1242 		case PIOD_READ_D:
1243 		case PIOD_READ_I:
1244 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1245 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1246 			uio.uio_rw = UIO_READ;
1247 			break;
1248 		case PIOD_WRITE_D:
1249 		case PIOD_WRITE_I:
1250 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1251 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1252 			td2->td_dbgflags |= TDB_USERWR;
1253 			uio.uio_rw = UIO_WRITE;
1254 			break;
1255 		default:
1256 			error = EINVAL;
1257 			goto out;
1258 		}
1259 		PROC_UNLOCK(p);
1260 		error = proc_rwmem(p, &uio);
1261 #ifdef COMPAT_FREEBSD32
1262 		if (wrap32)
1263 			piod32->piod_len -= uio.uio_resid;
1264 		else
1265 #endif
1266 			piod->piod_len -= uio.uio_resid;
1267 		PROC_LOCK(p);
1268 		break;
1269 
1270 	case PT_KILL:
1271 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1272 		data = SIGKILL;
1273 		goto sendsig;	/* in PT_CONTINUE above */
1274 
1275 	case PT_SETREGS:
1276 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1277 		    p->p_pid);
1278 		td2->td_dbgflags |= TDB_USERWR;
1279 		error = PROC_WRITE(regs, td2, addr);
1280 		break;
1281 
1282 	case PT_GETREGS:
1283 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1284 		    p->p_pid);
1285 		error = PROC_READ(regs, td2, addr);
1286 		break;
1287 
1288 	case PT_SETFPREGS:
1289 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1290 		    p->p_pid);
1291 		td2->td_dbgflags |= TDB_USERWR;
1292 		error = PROC_WRITE(fpregs, td2, addr);
1293 		break;
1294 
1295 	case PT_GETFPREGS:
1296 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1297 		    p->p_pid);
1298 		error = PROC_READ(fpregs, td2, addr);
1299 		break;
1300 
1301 	case PT_SETDBREGS:
1302 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1303 		    p->p_pid);
1304 		td2->td_dbgflags |= TDB_USERWR;
1305 		error = PROC_WRITE(dbregs, td2, addr);
1306 		break;
1307 
1308 	case PT_GETDBREGS:
1309 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1310 		    p->p_pid);
1311 		error = PROC_READ(dbregs, td2, addr);
1312 		break;
1313 
1314 	case PT_LWPINFO:
1315 		if (data <= 0 ||
1316 #ifdef COMPAT_FREEBSD32
1317 		    (!wrap32 && data > sizeof(*pl)) ||
1318 		    (wrap32 && data > sizeof(*pl32))) {
1319 #else
1320 		    data > sizeof(*pl)) {
1321 #endif
1322 			error = EINVAL;
1323 			break;
1324 		}
1325 #ifdef COMPAT_FREEBSD32
1326 		if (wrap32) {
1327 			pl = &plr;
1328 			pl32 = addr;
1329 		} else
1330 #endif
1331 		pl = addr;
1332 		bzero(pl, sizeof(*pl));
1333 		pl->pl_lwpid = td2->td_tid;
1334 		pl->pl_event = PL_EVENT_NONE;
1335 		pl->pl_flags = 0;
1336 		if (td2->td_dbgflags & TDB_XSIG) {
1337 			pl->pl_event = PL_EVENT_SIGNAL;
1338 			if (td2->td_si.si_signo != 0 &&
1339 #ifdef COMPAT_FREEBSD32
1340 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1341 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1342 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1343 			    pl_siginfo) + sizeof(struct siginfo32)))
1344 #else
1345 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1346 			    + sizeof(pl->pl_siginfo)
1347 #endif
1348 			){
1349 				pl->pl_flags |= PL_FLAG_SI;
1350 				pl->pl_siginfo = td2->td_si;
1351 			}
1352 		}
1353 		if (td2->td_dbgflags & TDB_SCE)
1354 			pl->pl_flags |= PL_FLAG_SCE;
1355 		else if (td2->td_dbgflags & TDB_SCX)
1356 			pl->pl_flags |= PL_FLAG_SCX;
1357 		if (td2->td_dbgflags & TDB_EXEC)
1358 			pl->pl_flags |= PL_FLAG_EXEC;
1359 		if (td2->td_dbgflags & TDB_FORK) {
1360 			pl->pl_flags |= PL_FLAG_FORKED;
1361 			pl->pl_child_pid = td2->td_dbg_forked;
1362 			if (td2->td_dbgflags & TDB_VFORK)
1363 				pl->pl_flags |= PL_FLAG_VFORKED;
1364 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1365 		    TDB_VFORK)
1366 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1367 		if (td2->td_dbgflags & TDB_CHILD)
1368 			pl->pl_flags |= PL_FLAG_CHILD;
1369 		if (td2->td_dbgflags & TDB_BORN)
1370 			pl->pl_flags |= PL_FLAG_BORN;
1371 		if (td2->td_dbgflags & TDB_EXIT)
1372 			pl->pl_flags |= PL_FLAG_EXITED;
1373 		pl->pl_sigmask = td2->td_sigmask;
1374 		pl->pl_siglist = td2->td_siglist;
1375 		strcpy(pl->pl_tdname, td2->td_name);
1376 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1377 			pl->pl_syscall_code = td2->td_sa.code;
1378 			pl->pl_syscall_narg = td2->td_sa.narg;
1379 		} else {
1380 			pl->pl_syscall_code = 0;
1381 			pl->pl_syscall_narg = 0;
1382 		}
1383 #ifdef COMPAT_FREEBSD32
1384 		if (wrap32)
1385 			ptrace_lwpinfo_to32(pl, pl32);
1386 #endif
1387 		CTR6(KTR_PTRACE,
1388     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1389 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1390 		    pl->pl_child_pid, pl->pl_syscall_code);
1391 		break;
1392 
1393 	case PT_GETNUMLWPS:
1394 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1395 		    p->p_numthreads);
1396 		td->td_retval[0] = p->p_numthreads;
1397 		break;
1398 
1399 	case PT_GETLWPLIST:
1400 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1401 		    p->p_pid, data, p->p_numthreads);
1402 		if (data <= 0) {
1403 			error = EINVAL;
1404 			break;
1405 		}
1406 		num = imin(p->p_numthreads, data);
1407 		PROC_UNLOCK(p);
1408 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1409 		tmp = 0;
1410 		PROC_LOCK(p);
1411 		FOREACH_THREAD_IN_PROC(p, td2) {
1412 			if (tmp >= num)
1413 				break;
1414 			buf[tmp++] = td2->td_tid;
1415 		}
1416 		PROC_UNLOCK(p);
1417 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1418 		free(buf, M_TEMP);
1419 		if (!error)
1420 			td->td_retval[0] = tmp;
1421 		PROC_LOCK(p);
1422 		break;
1423 
1424 	case PT_VM_TIMESTAMP:
1425 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1426 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1427 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1428 		break;
1429 
1430 	case PT_VM_ENTRY:
1431 		PROC_UNLOCK(p);
1432 #ifdef COMPAT_FREEBSD32
1433 		if (wrap32)
1434 			error = ptrace_vm_entry32(td, p, addr);
1435 		else
1436 #endif
1437 		error = ptrace_vm_entry(td, p, addr);
1438 		PROC_LOCK(p);
1439 		break;
1440 
1441 	default:
1442 #ifdef __HAVE_PTRACE_MACHDEP
1443 		if (req >= PT_FIRSTMACH) {
1444 			PROC_UNLOCK(p);
1445 			error = cpu_ptrace(td2, req, addr, data);
1446 			PROC_LOCK(p);
1447 		} else
1448 #endif
1449 			/* Unknown request. */
1450 			error = EINVAL;
1451 		break;
1452 	}
1453 
1454 out:
1455 	/* Drop our hold on this process now that the request has completed. */
1456 	_PRELE(p);
1457 fail:
1458 	PROC_UNLOCK(p);
1459 	if (proctree_locked)
1460 		sx_xunlock(&proctree_lock);
1461 	return (error);
1462 }
1463 #undef PROC_READ
1464 #undef PROC_WRITE
1465 
1466 /*
1467  * Stop a process because of a debugging event;
1468  * stay stopped until p->p_step is cleared
1469  * (cleared by PIOCCONT in procfs).
1470  */
1471 void
1472 stopevent(struct proc *p, unsigned int event, unsigned int val)
1473 {
1474 
1475 	PROC_LOCK_ASSERT(p, MA_OWNED);
1476 	p->p_step = 1;
1477 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1478 	    val);
1479 	do {
1480 		if (event != S_EXIT)
1481 			p->p_xsig = val;
1482 		p->p_xthread = NULL;
1483 		p->p_stype = event;	/* Which event caused the stop? */
1484 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1485 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1486 	} while (p->p_step);
1487 }
1488