xref: /freebsd/sys/kern/sys_process.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
1 /*-
2  * Copyright (c) 1994, Sean Eric Fagan
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by Sean Eric Fagan.
16  * 4. The name of the author may not be used to endorse or promote products
17  *    derived from this software without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_compat.h"
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 
91 struct ptrace_lwpinfo32 {
92 	lwpid_t	pl_lwpid;	/* LWP described. */
93 	int	pl_event;	/* Event that stopped the LWP. */
94 	int	pl_flags;	/* LWP flags. */
95 	sigset_t	pl_sigmask;	/* LWP signal mask */
96 	sigset_t	pl_siglist;	/* LWP pending signal */
97 	struct siginfo32 pl_siginfo;	/* siginfo for signal */
98 	char	pl_tdname[MAXCOMLEN + 1];	/* LWP name. */
99 	pid_t	pl_child_pid;		/* New child pid */
100 	u_int		pl_syscall_code;
101 	u_int		pl_syscall_narg;
102 };
103 
104 #endif
105 
106 /*
107  * Functions implemented using PROC_ACTION():
108  *
109  * proc_read_regs(proc, regs)
110  *	Get the current user-visible register set from the process
111  *	and copy it into the regs structure (<machine/reg.h>).
112  *	The process is stopped at the time read_regs is called.
113  *
114  * proc_write_regs(proc, regs)
115  *	Update the current register set from the passed in regs
116  *	structure.  Take care to avoid clobbering special CPU
117  *	registers or privileged bits in the PSL.
118  *	Depending on the architecture this may have fix-up work to do,
119  *	especially if the IAR or PCW are modified.
120  *	The process is stopped at the time write_regs is called.
121  *
122  * proc_read_fpregs, proc_write_fpregs
123  *	deal with the floating point register set, otherwise as above.
124  *
125  * proc_read_dbregs, proc_write_dbregs
126  *	deal with the processor debug register set, otherwise as above.
127  *
128  * proc_sstep(proc)
129  *	Arrange for the process to trap after executing a single instruction.
130  */
131 
132 #define	PROC_ACTION(action) do {					\
133 	int error;							\
134 									\
135 	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
136 	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
137 		error = EIO;						\
138 	else								\
139 		error = (action);					\
140 	return (error);							\
141 } while(0)
142 
143 int
144 proc_read_regs(struct thread *td, struct reg *regs)
145 {
146 
147 	PROC_ACTION(fill_regs(td, regs));
148 }
149 
150 int
151 proc_write_regs(struct thread *td, struct reg *regs)
152 {
153 
154 	PROC_ACTION(set_regs(td, regs));
155 }
156 
157 int
158 proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
159 {
160 
161 	PROC_ACTION(fill_dbregs(td, dbregs));
162 }
163 
164 int
165 proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
166 {
167 
168 	PROC_ACTION(set_dbregs(td, dbregs));
169 }
170 
171 /*
172  * Ptrace doesn't support fpregs at all, and there are no security holes
173  * or translations for fpregs, so we can just copy them.
174  */
175 int
176 proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
177 {
178 
179 	PROC_ACTION(fill_fpregs(td, fpregs));
180 }
181 
182 int
183 proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
184 {
185 
186 	PROC_ACTION(set_fpregs(td, fpregs));
187 }
188 
189 #ifdef COMPAT_FREEBSD32
190 /* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
191 int
192 proc_read_regs32(struct thread *td, struct reg32 *regs32)
193 {
194 
195 	PROC_ACTION(fill_regs32(td, regs32));
196 }
197 
198 int
199 proc_write_regs32(struct thread *td, struct reg32 *regs32)
200 {
201 
202 	PROC_ACTION(set_regs32(td, regs32));
203 }
204 
205 int
206 proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
207 {
208 
209 	PROC_ACTION(fill_dbregs32(td, dbregs32));
210 }
211 
212 int
213 proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
214 {
215 
216 	PROC_ACTION(set_dbregs32(td, dbregs32));
217 }
218 
219 int
220 proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
221 {
222 
223 	PROC_ACTION(fill_fpregs32(td, fpregs32));
224 }
225 
226 int
227 proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
228 {
229 
230 	PROC_ACTION(set_fpregs32(td, fpregs32));
231 }
232 #endif
233 
234 int
235 proc_sstep(struct thread *td)
236 {
237 
238 	PROC_ACTION(ptrace_single_step(td));
239 }
240 
241 int
242 proc_rwmem(struct proc *p, struct uio *uio)
243 {
244 	vm_map_t map;
245 	vm_offset_t pageno;		/* page number */
246 	vm_prot_t reqprot;
247 	int error, fault_flags, page_offset, writing;
248 
249 	/*
250 	 * Assert that someone has locked this vmspace.  (Should be
251 	 * curthread but we can't assert that.)  This keeps the process
252 	 * from exiting out from under us until this operation completes.
253 	 */
254 	PROC_ASSERT_HELD(p);
255 	PROC_LOCK_ASSERT(p, MA_NOTOWNED);
256 
257 	/*
258 	 * The map we want...
259 	 */
260 	map = &p->p_vmspace->vm_map;
261 
262 	/*
263 	 * If we are writing, then we request vm_fault() to create a private
264 	 * copy of each page.  Since these copies will not be writeable by the
265 	 * process, we must explicity request that they be dirtied.
266 	 */
267 	writing = uio->uio_rw == UIO_WRITE;
268 	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
269 	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
270 
271 	/*
272 	 * Only map in one page at a time.  We don't have to, but it
273 	 * makes things easier.  This way is trivial - right?
274 	 */
275 	do {
276 		vm_offset_t uva;
277 		u_int len;
278 		vm_page_t m;
279 
280 		uva = (vm_offset_t)uio->uio_offset;
281 
282 		/*
283 		 * Get the page number of this segment.
284 		 */
285 		pageno = trunc_page(uva);
286 		page_offset = uva - pageno;
287 
288 		/*
289 		 * How many bytes to copy
290 		 */
291 		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
292 
293 		/*
294 		 * Fault and hold the page on behalf of the process.
295 		 */
296 		error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
297 		if (error != KERN_SUCCESS) {
298 			if (error == KERN_RESOURCE_SHORTAGE)
299 				error = ENOMEM;
300 			else
301 				error = EFAULT;
302 			break;
303 		}
304 
305 		/*
306 		 * Now do the i/o move.
307 		 */
308 		error = uiomove_fromphys(&m, page_offset, len, uio);
309 
310 		/* Make the I-cache coherent for breakpoints. */
311 		if (writing && error == 0) {
312 			vm_map_lock_read(map);
313 			if (vm_map_check_protection(map, pageno, pageno +
314 			    PAGE_SIZE, VM_PROT_EXECUTE))
315 				vm_sync_icache(map, uva, len);
316 			vm_map_unlock_read(map);
317 		}
318 
319 		/*
320 		 * Release the page.
321 		 */
322 		vm_page_lock(m);
323 		vm_page_unhold(m);
324 		vm_page_unlock(m);
325 
326 	} while (error == 0 && uio->uio_resid > 0);
327 
328 	return (error);
329 }
330 
331 static ssize_t
332 proc_iop(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
333     size_t len, enum uio_rw rw)
334 {
335 	struct iovec iov;
336 	struct uio uio;
337 	ssize_t slen;
338 	int error;
339 
340 	MPASS(len < SSIZE_MAX);
341 	slen = (ssize_t)len;
342 
343 	iov.iov_base = (caddr_t)buf;
344 	iov.iov_len = len;
345 	uio.uio_iov = &iov;
346 	uio.uio_iovcnt = 1;
347 	uio.uio_offset = va;
348 	uio.uio_resid = slen;
349 	uio.uio_segflg = UIO_SYSSPACE;
350 	uio.uio_rw = rw;
351 	uio.uio_td = td;
352 	error = proc_rwmem(p, &uio);
353 	if (uio.uio_resid == slen)
354 		return (-1);
355 	return (slen - uio.uio_resid);
356 }
357 
358 ssize_t
359 proc_readmem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
360     size_t len)
361 {
362 
363 	return (proc_iop(td, p, va, buf, len, UIO_READ));
364 }
365 
366 ssize_t
367 proc_writemem(struct thread *td, struct proc *p, vm_offset_t va, void *buf,
368     size_t len)
369 {
370 
371 	return (proc_iop(td, p, va, buf, len, UIO_WRITE));
372 }
373 
374 static int
375 ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
376 {
377 	struct vattr vattr;
378 	vm_map_t map;
379 	vm_map_entry_t entry;
380 	vm_object_t obj, tobj, lobj;
381 	struct vmspace *vm;
382 	struct vnode *vp;
383 	char *freepath, *fullpath;
384 	u_int pathlen;
385 	int error, index;
386 
387 	error = 0;
388 	obj = NULL;
389 
390 	vm = vmspace_acquire_ref(p);
391 	map = &vm->vm_map;
392 	vm_map_lock_read(map);
393 
394 	do {
395 		entry = map->header.next;
396 		index = 0;
397 		while (index < pve->pve_entry && entry != &map->header) {
398 			entry = entry->next;
399 			index++;
400 		}
401 		if (index != pve->pve_entry) {
402 			error = EINVAL;
403 			break;
404 		}
405 		while (entry != &map->header &&
406 		    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
407 			entry = entry->next;
408 			index++;
409 		}
410 		if (entry == &map->header) {
411 			error = ENOENT;
412 			break;
413 		}
414 
415 		/* We got an entry. */
416 		pve->pve_entry = index + 1;
417 		pve->pve_timestamp = map->timestamp;
418 		pve->pve_start = entry->start;
419 		pve->pve_end = entry->end - 1;
420 		pve->pve_offset = entry->offset;
421 		pve->pve_prot = entry->protection;
422 
423 		/* Backing object's path needed? */
424 		if (pve->pve_pathlen == 0)
425 			break;
426 
427 		pathlen = pve->pve_pathlen;
428 		pve->pve_pathlen = 0;
429 
430 		obj = entry->object.vm_object;
431 		if (obj != NULL)
432 			VM_OBJECT_RLOCK(obj);
433 	} while (0);
434 
435 	vm_map_unlock_read(map);
436 
437 	pve->pve_fsid = VNOVAL;
438 	pve->pve_fileid = VNOVAL;
439 
440 	if (error == 0 && obj != NULL) {
441 		lobj = obj;
442 		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
443 			if (tobj != obj)
444 				VM_OBJECT_RLOCK(tobj);
445 			if (lobj != obj)
446 				VM_OBJECT_RUNLOCK(lobj);
447 			lobj = tobj;
448 			pve->pve_offset += tobj->backing_object_offset;
449 		}
450 		vp = vm_object_vnode(lobj);
451 		if (vp != NULL)
452 			vref(vp);
453 		if (lobj != obj)
454 			VM_OBJECT_RUNLOCK(lobj);
455 		VM_OBJECT_RUNLOCK(obj);
456 
457 		if (vp != NULL) {
458 			freepath = NULL;
459 			fullpath = NULL;
460 			vn_fullpath(td, vp, &fullpath, &freepath);
461 			vn_lock(vp, LK_SHARED | LK_RETRY);
462 			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
463 				pve->pve_fileid = vattr.va_fileid;
464 				pve->pve_fsid = vattr.va_fsid;
465 			}
466 			vput(vp);
467 
468 			if (fullpath != NULL) {
469 				pve->pve_pathlen = strlen(fullpath) + 1;
470 				if (pve->pve_pathlen <= pathlen) {
471 					error = copyout(fullpath, pve->pve_path,
472 					    pve->pve_pathlen);
473 				} else
474 					error = ENAMETOOLONG;
475 			}
476 			if (freepath != NULL)
477 				free(freepath, M_TEMP);
478 		}
479 	}
480 	vmspace_free(vm);
481 	if (error == 0)
482 		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
483 		    p->p_pid, pve->pve_entry, pve->pve_start);
484 
485 	return (error);
486 }
487 
488 #ifdef COMPAT_FREEBSD32
489 static int
490 ptrace_vm_entry32(struct thread *td, struct proc *p,
491     struct ptrace_vm_entry32 *pve32)
492 {
493 	struct ptrace_vm_entry pve;
494 	int error;
495 
496 	pve.pve_entry = pve32->pve_entry;
497 	pve.pve_pathlen = pve32->pve_pathlen;
498 	pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
499 
500 	error = ptrace_vm_entry(td, p, &pve);
501 	if (error == 0) {
502 		pve32->pve_entry = pve.pve_entry;
503 		pve32->pve_timestamp = pve.pve_timestamp;
504 		pve32->pve_start = pve.pve_start;
505 		pve32->pve_end = pve.pve_end;
506 		pve32->pve_offset = pve.pve_offset;
507 		pve32->pve_prot = pve.pve_prot;
508 		pve32->pve_fileid = pve.pve_fileid;
509 		pve32->pve_fsid = pve.pve_fsid;
510 	}
511 
512 	pve32->pve_pathlen = pve.pve_pathlen;
513 	return (error);
514 }
515 
516 static void
517 ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
518     struct ptrace_lwpinfo32 *pl32)
519 {
520 
521 	pl32->pl_lwpid = pl->pl_lwpid;
522 	pl32->pl_event = pl->pl_event;
523 	pl32->pl_flags = pl->pl_flags;
524 	pl32->pl_sigmask = pl->pl_sigmask;
525 	pl32->pl_siglist = pl->pl_siglist;
526 	siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
527 	strcpy(pl32->pl_tdname, pl->pl_tdname);
528 	pl32->pl_child_pid = pl->pl_child_pid;
529 	pl32->pl_syscall_code = pl->pl_syscall_code;
530 	pl32->pl_syscall_narg = pl->pl_syscall_narg;
531 }
532 #endif /* COMPAT_FREEBSD32 */
533 
534 /*
535  * Process debugging system call.
536  */
537 #ifndef _SYS_SYSPROTO_H_
538 struct ptrace_args {
539 	int	req;
540 	pid_t	pid;
541 	caddr_t	addr;
542 	int	data;
543 };
544 #endif
545 
546 #ifdef COMPAT_FREEBSD32
547 /*
548  * This CPP subterfuge is to try and reduce the number of ifdefs in
549  * the body of the code.
550  *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
551  * becomes either:
552  *   copyin(uap->addr, &r.reg, sizeof r.reg);
553  * or
554  *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
555  * .. except this is done at runtime.
556  */
557 #define	COPYIN(u, k, s)		wrap32 ? \
558 	copyin(u, k ## 32, s ## 32) : \
559 	copyin(u, k, s)
560 #define	COPYOUT(k, u, s)	wrap32 ? \
561 	copyout(k ## 32, u, s ## 32) : \
562 	copyout(k, u, s)
563 #else
564 #define	COPYIN(u, k, s)		copyin(u, k, s)
565 #define	COPYOUT(k, u, s)	copyout(k, u, s)
566 #endif
567 int
568 sys_ptrace(struct thread *td, struct ptrace_args *uap)
569 {
570 	/*
571 	 * XXX this obfuscation is to reduce stack usage, but the register
572 	 * structs may be too large to put on the stack anyway.
573 	 */
574 	union {
575 		struct ptrace_io_desc piod;
576 		struct ptrace_lwpinfo pl;
577 		struct ptrace_vm_entry pve;
578 		struct dbreg dbreg;
579 		struct fpreg fpreg;
580 		struct reg reg;
581 #ifdef COMPAT_FREEBSD32
582 		struct dbreg32 dbreg32;
583 		struct fpreg32 fpreg32;
584 		struct reg32 reg32;
585 		struct ptrace_io_desc32 piod32;
586 		struct ptrace_lwpinfo32 pl32;
587 		struct ptrace_vm_entry32 pve32;
588 #endif
589 		int ptevents;
590 	} r;
591 	void *addr;
592 	int error = 0;
593 #ifdef COMPAT_FREEBSD32
594 	int wrap32 = 0;
595 
596 	if (SV_CURPROC_FLAG(SV_ILP32))
597 		wrap32 = 1;
598 #endif
599 	AUDIT_ARG_PID(uap->pid);
600 	AUDIT_ARG_CMD(uap->req);
601 	AUDIT_ARG_VALUE(uap->data);
602 	addr = &r;
603 	switch (uap->req) {
604 	case PT_GET_EVENT_MASK:
605 	case PT_GETREGS:
606 	case PT_GETFPREGS:
607 	case PT_GETDBREGS:
608 	case PT_LWPINFO:
609 		break;
610 	case PT_SETREGS:
611 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
612 		break;
613 	case PT_SETFPREGS:
614 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
615 		break;
616 	case PT_SETDBREGS:
617 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
618 		break;
619 	case PT_SET_EVENT_MASK:
620 		if (uap->data != sizeof(r.ptevents))
621 			error = EINVAL;
622 		else
623 			error = copyin(uap->addr, &r.ptevents, uap->data);
624 		break;
625 	case PT_IO:
626 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
627 		break;
628 	case PT_VM_ENTRY:
629 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
630 		break;
631 	default:
632 		addr = uap->addr;
633 		break;
634 	}
635 	if (error)
636 		return (error);
637 
638 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
639 	if (error)
640 		return (error);
641 
642 	switch (uap->req) {
643 	case PT_VM_ENTRY:
644 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
645 		break;
646 	case PT_IO:
647 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
648 		break;
649 	case PT_GETREGS:
650 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
651 		break;
652 	case PT_GETFPREGS:
653 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
654 		break;
655 	case PT_GETDBREGS:
656 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
657 		break;
658 	case PT_GET_EVENT_MASK:
659 		/* NB: The size in uap->data is validated in kern_ptrace(). */
660 		error = copyout(&r.ptevents, uap->addr, uap->data);
661 		break;
662 	case PT_LWPINFO:
663 		/* NB: The size in uap->data is validated in kern_ptrace(). */
664 		error = copyout(&r.pl, uap->addr, uap->data);
665 		break;
666 	}
667 
668 	return (error);
669 }
670 #undef COPYIN
671 #undef COPYOUT
672 
673 #ifdef COMPAT_FREEBSD32
674 /*
675  *   PROC_READ(regs, td2, addr);
676  * becomes either:
677  *   proc_read_regs(td2, addr);
678  * or
679  *   proc_read_regs32(td2, addr);
680  * .. except this is done at runtime.  There is an additional
681  * complication in that PROC_WRITE disallows 32 bit consumers
682  * from writing to 64 bit address space targets.
683  */
684 #define	PROC_READ(w, t, a)	wrap32 ? \
685 	proc_read_ ## w ## 32(t, a) : \
686 	proc_read_ ## w (t, a)
687 #define	PROC_WRITE(w, t, a)	wrap32 ? \
688 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
689 	proc_write_ ## w (t, a)
690 #else
691 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
692 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
693 #endif
694 
695 void
696 proc_set_traced(struct proc *p, bool stop)
697 {
698 
699 	PROC_LOCK_ASSERT(p, MA_OWNED);
700 	p->p_flag |= P_TRACED;
701 	if (stop)
702 		p->p_flag2 |= P2_PTRACE_FSTP;
703 	p->p_ptevents = PTRACE_DEFAULT;
704 	p->p_oppid = p->p_pptr->p_pid;
705 }
706 
707 int
708 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
709 {
710 	struct iovec iov;
711 	struct uio uio;
712 	struct proc *curp, *p, *pp;
713 	struct thread *td2 = NULL, *td3;
714 	struct ptrace_io_desc *piod = NULL;
715 	struct ptrace_lwpinfo *pl;
716 	int error, num, tmp;
717 	int proctree_locked = 0;
718 	lwpid_t tid = 0, *buf;
719 #ifdef COMPAT_FREEBSD32
720 	int wrap32 = 0, safe = 0;
721 	struct ptrace_io_desc32 *piod32 = NULL;
722 	struct ptrace_lwpinfo32 *pl32 = NULL;
723 	struct ptrace_lwpinfo plr;
724 #endif
725 
726 	curp = td->td_proc;
727 
728 	/* Lock proctree before locking the process. */
729 	switch (req) {
730 	case PT_TRACE_ME:
731 	case PT_ATTACH:
732 	case PT_STEP:
733 	case PT_CONTINUE:
734 	case PT_TO_SCE:
735 	case PT_TO_SCX:
736 	case PT_SYSCALL:
737 	case PT_FOLLOW_FORK:
738 	case PT_LWP_EVENTS:
739 	case PT_GET_EVENT_MASK:
740 	case PT_SET_EVENT_MASK:
741 	case PT_DETACH:
742 		sx_xlock(&proctree_lock);
743 		proctree_locked = 1;
744 		break;
745 	default:
746 		break;
747 	}
748 
749 	if (req == PT_TRACE_ME) {
750 		p = td->td_proc;
751 		PROC_LOCK(p);
752 	} else {
753 		if (pid <= PID_MAX) {
754 			if ((p = pfind(pid)) == NULL) {
755 				if (proctree_locked)
756 					sx_xunlock(&proctree_lock);
757 				return (ESRCH);
758 			}
759 		} else {
760 			td2 = tdfind(pid, -1);
761 			if (td2 == NULL) {
762 				if (proctree_locked)
763 					sx_xunlock(&proctree_lock);
764 				return (ESRCH);
765 			}
766 			p = td2->td_proc;
767 			tid = pid;
768 			pid = p->p_pid;
769 		}
770 	}
771 	AUDIT_ARG_PROCESS(p);
772 
773 	if ((p->p_flag & P_WEXIT) != 0) {
774 		error = ESRCH;
775 		goto fail;
776 	}
777 	if ((error = p_cansee(td, p)) != 0)
778 		goto fail;
779 
780 	if ((error = p_candebug(td, p)) != 0)
781 		goto fail;
782 
783 	/*
784 	 * System processes can't be debugged.
785 	 */
786 	if ((p->p_flag & P_SYSTEM) != 0) {
787 		error = EINVAL;
788 		goto fail;
789 	}
790 
791 	if (tid == 0) {
792 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
793 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
794 			td2 = p->p_xthread;
795 		} else {
796 			td2 = FIRST_THREAD_IN_PROC(p);
797 		}
798 		tid = td2->td_tid;
799 	}
800 
801 #ifdef COMPAT_FREEBSD32
802 	/*
803 	 * Test if we're a 32 bit client and what the target is.
804 	 * Set the wrap controls accordingly.
805 	 */
806 	if (SV_CURPROC_FLAG(SV_ILP32)) {
807 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
808 			safe = 1;
809 		wrap32 = 1;
810 	}
811 #endif
812 	/*
813 	 * Permissions check
814 	 */
815 	switch (req) {
816 	case PT_TRACE_ME:
817 		/*
818 		 * Always legal, when there is a parent process which
819 		 * could trace us.  Otherwise, reject.
820 		 */
821 		if ((p->p_flag & P_TRACED) != 0) {
822 			error = EBUSY;
823 			goto fail;
824 		}
825 		if (p->p_pptr == initproc) {
826 			error = EPERM;
827 			goto fail;
828 		}
829 		break;
830 
831 	case PT_ATTACH:
832 		/* Self */
833 		if (p == td->td_proc) {
834 			error = EINVAL;
835 			goto fail;
836 		}
837 
838 		/* Already traced */
839 		if (p->p_flag & P_TRACED) {
840 			error = EBUSY;
841 			goto fail;
842 		}
843 
844 		/* Can't trace an ancestor if you're being traced. */
845 		if (curp->p_flag & P_TRACED) {
846 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
847 				if (pp == p) {
848 					error = EINVAL;
849 					goto fail;
850 				}
851 			}
852 		}
853 
854 
855 		/* OK */
856 		break;
857 
858 	case PT_CLEARSTEP:
859 		/* Allow thread to clear single step for itself */
860 		if (td->td_tid == tid)
861 			break;
862 
863 		/* FALLTHROUGH */
864 	default:
865 		/* not being traced... */
866 		if ((p->p_flag & P_TRACED) == 0) {
867 			error = EPERM;
868 			goto fail;
869 		}
870 
871 		/* not being traced by YOU */
872 		if (p->p_pptr != td->td_proc) {
873 			error = EBUSY;
874 			goto fail;
875 		}
876 
877 		/* not currently stopped */
878 		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
879 		    p->p_suspcount != p->p_numthreads  ||
880 		    (p->p_flag & P_WAITED) == 0) {
881 			error = EBUSY;
882 			goto fail;
883 		}
884 
885 		if ((p->p_flag & P_STOPPED_TRACE) == 0) {
886 			static int count = 0;
887 			if (count++ == 0)
888 				printf("P_STOPPED_TRACE not set.\n");
889 		}
890 
891 		/* OK */
892 		break;
893 	}
894 
895 	/* Keep this process around until we finish this request. */
896 	_PHOLD(p);
897 
898 #ifdef FIX_SSTEP
899 	/*
900 	 * Single step fixup ala procfs
901 	 */
902 	FIX_SSTEP(td2);
903 #endif
904 
905 	/*
906 	 * Actually do the requests
907 	 */
908 
909 	td->td_retval[0] = 0;
910 
911 	switch (req) {
912 	case PT_TRACE_ME:
913 		/* set my trace flag and "owner" so it can read/write me */
914 		proc_set_traced(p, false);
915 		if (p->p_flag & P_PPWAIT)
916 			p->p_flag |= P_PPTRACE;
917 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
918 		break;
919 
920 	case PT_ATTACH:
921 		/* security check done above */
922 		/*
923 		 * It would be nice if the tracing relationship was separate
924 		 * from the parent relationship but that would require
925 		 * another set of links in the proc struct or for "wait"
926 		 * to scan the entire proc table.  To make life easier,
927 		 * we just re-parent the process we're trying to trace.
928 		 * The old parent is remembered so we can put things back
929 		 * on a "detach".
930 		 */
931 		proc_set_traced(p, true);
932 		if (p->p_pptr != td->td_proc) {
933 			proc_reparent(p, td->td_proc);
934 		}
935 		data = SIGSTOP;
936 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
937 		    p->p_oppid);
938 		goto sendsig;	/* in PT_CONTINUE below */
939 
940 	case PT_CLEARSTEP:
941 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
942 		    p->p_pid);
943 		error = ptrace_clear_single_step(td2);
944 		break;
945 
946 	case PT_SETSTEP:
947 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
948 		    p->p_pid);
949 		error = ptrace_single_step(td2);
950 		break;
951 
952 	case PT_SUSPEND:
953 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
954 		    p->p_pid);
955 		td2->td_dbgflags |= TDB_SUSPEND;
956 		thread_lock(td2);
957 		td2->td_flags |= TDF_NEEDSUSPCHK;
958 		thread_unlock(td2);
959 		break;
960 
961 	case PT_RESUME:
962 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
963 		    p->p_pid);
964 		td2->td_dbgflags &= ~TDB_SUSPEND;
965 		break;
966 
967 	case PT_FOLLOW_FORK:
968 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
969 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
970 		    data ? "enabled" : "disabled");
971 		if (data)
972 			p->p_ptevents |= PTRACE_FORK;
973 		else
974 			p->p_ptevents &= ~PTRACE_FORK;
975 		break;
976 
977 	case PT_LWP_EVENTS:
978 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
979 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
980 		    data ? "enabled" : "disabled");
981 		if (data)
982 			p->p_ptevents |= PTRACE_LWP;
983 		else
984 			p->p_ptevents &= ~PTRACE_LWP;
985 		break;
986 
987 	case PT_GET_EVENT_MASK:
988 		if (data != sizeof(p->p_ptevents)) {
989 			error = EINVAL;
990 			break;
991 		}
992 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
993 		    p->p_ptevents);
994 		*(int *)addr = p->p_ptevents;
995 		break;
996 
997 	case PT_SET_EVENT_MASK:
998 		if (data != sizeof(p->p_ptevents)) {
999 			error = EINVAL;
1000 			break;
1001 		}
1002 		tmp = *(int *)addr;
1003 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1004 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1005 			error = EINVAL;
1006 			break;
1007 		}
1008 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1009 		    p->p_pid, p->p_ptevents, tmp);
1010 		p->p_ptevents = tmp;
1011 		break;
1012 
1013 	case PT_STEP:
1014 	case PT_CONTINUE:
1015 	case PT_TO_SCE:
1016 	case PT_TO_SCX:
1017 	case PT_SYSCALL:
1018 	case PT_DETACH:
1019 		/* Zero means do not send any signal */
1020 		if (data < 0 || data > _SIG_MAXSIG) {
1021 			error = EINVAL;
1022 			break;
1023 		}
1024 
1025 		switch (req) {
1026 		case PT_STEP:
1027 			CTR2(KTR_PTRACE, "PT_STEP: tid %d (pid %d)",
1028 			    td2->td_tid, p->p_pid);
1029 			error = ptrace_single_step(td2);
1030 			if (error)
1031 				goto out;
1032 			break;
1033 		case PT_CONTINUE:
1034 		case PT_TO_SCE:
1035 		case PT_TO_SCX:
1036 		case PT_SYSCALL:
1037 			if (addr != (void *)1) {
1038 				error = ptrace_set_pc(td2,
1039 				    (u_long)(uintfptr_t)addr);
1040 				if (error)
1041 					goto out;
1042 			}
1043 			switch (req) {
1044 			case PT_TO_SCE:
1045 				p->p_ptevents |= PTRACE_SCE;
1046 				CTR4(KTR_PTRACE,
1047 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1048 				    p->p_pid, p->p_ptevents,
1049 				    (u_long)(uintfptr_t)addr, data);
1050 				break;
1051 			case PT_TO_SCX:
1052 				p->p_ptevents |= PTRACE_SCX;
1053 				CTR4(KTR_PTRACE,
1054 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1055 				    p->p_pid, p->p_ptevents,
1056 				    (u_long)(uintfptr_t)addr, data);
1057 				break;
1058 			case PT_SYSCALL:
1059 				p->p_ptevents |= PTRACE_SYSCALL;
1060 				CTR4(KTR_PTRACE,
1061 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1062 				    p->p_pid, p->p_ptevents,
1063 				    (u_long)(uintfptr_t)addr, data);
1064 				break;
1065 			case PT_CONTINUE:
1066 				CTR3(KTR_PTRACE,
1067 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1068 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1069 				break;
1070 			}
1071 			break;
1072 		case PT_DETACH:
1073 			/*
1074 			 * Reset the process parent.
1075 			 *
1076 			 * NB: This clears P_TRACED before reparenting
1077 			 * a detached process back to its original
1078 			 * parent.  Otherwise the debugee will be set
1079 			 * as an orphan of the debugger.
1080 			 */
1081 			p->p_flag &= ~(P_TRACED | P_WAITED);
1082 			if (p->p_oppid != p->p_pptr->p_pid) {
1083 				PROC_LOCK(p->p_pptr);
1084 				sigqueue_take(p->p_ksi);
1085 				PROC_UNLOCK(p->p_pptr);
1086 
1087 				pp = proc_realparent(p);
1088 				proc_reparent(p, pp);
1089 				if (pp == initproc)
1090 					p->p_sigparent = SIGCHLD;
1091 				CTR3(KTR_PTRACE,
1092 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1093 				    p->p_pid, pp->p_pid, data);
1094 			} else
1095 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1096 				    p->p_pid, data);
1097 			p->p_oppid = 0;
1098 			p->p_ptevents = 0;
1099 			FOREACH_THREAD_IN_PROC(p, td3) {
1100 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1101 					sigqueue_delete(&td3->td_sigqueue,
1102 					    SIGSTOP);
1103 				}
1104 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP);
1105 			}
1106 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1107 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1108 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1109 			}
1110 
1111 			/* should we send SIGCHLD? */
1112 			/* childproc_continued(p); */
1113 			break;
1114 		}
1115 
1116 	sendsig:
1117 		if (proctree_locked) {
1118 			sx_xunlock(&proctree_lock);
1119 			proctree_locked = 0;
1120 		}
1121 		p->p_xsig = data;
1122 		p->p_xthread = NULL;
1123 		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
1124 			/* deliver or queue signal */
1125 			td2->td_dbgflags &= ~TDB_XSIG;
1126 			td2->td_xsig = data;
1127 
1128 			if (req == PT_DETACH) {
1129 				FOREACH_THREAD_IN_PROC(p, td3)
1130 					td3->td_dbgflags &= ~TDB_SUSPEND;
1131 			}
1132 			/*
1133 			 * unsuspend all threads, to not let a thread run,
1134 			 * you should use PT_SUSPEND to suspend it before
1135 			 * continuing process.
1136 			 */
1137 			PROC_SLOCK(p);
1138 			p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
1139 			thread_unsuspend(p);
1140 			PROC_SUNLOCK(p);
1141 			if (req == PT_ATTACH)
1142 				kern_psignal(p, data);
1143 		} else {
1144 			if (data)
1145 				kern_psignal(p, data);
1146 		}
1147 		break;
1148 
1149 	case PT_WRITE_I:
1150 	case PT_WRITE_D:
1151 		td2->td_dbgflags |= TDB_USERWR;
1152 		PROC_UNLOCK(p);
1153 		error = 0;
1154 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1155 		    sizeof(int)) != sizeof(int))
1156 			error = ENOMEM;
1157 		else
1158 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1159 			    p->p_pid, addr, data);
1160 		PROC_LOCK(p);
1161 		break;
1162 
1163 	case PT_READ_I:
1164 	case PT_READ_D:
1165 		PROC_UNLOCK(p);
1166 		error = tmp = 0;
1167 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1168 		    sizeof(int)) != sizeof(int))
1169 			error = ENOMEM;
1170 		else
1171 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1172 			    p->p_pid, addr, tmp);
1173 		td->td_retval[0] = tmp;
1174 		PROC_LOCK(p);
1175 		break;
1176 
1177 	case PT_IO:
1178 #ifdef COMPAT_FREEBSD32
1179 		if (wrap32) {
1180 			piod32 = addr;
1181 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1182 			iov.iov_len = piod32->piod_len;
1183 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1184 			uio.uio_resid = piod32->piod_len;
1185 		} else
1186 #endif
1187 		{
1188 			piod = addr;
1189 			iov.iov_base = piod->piod_addr;
1190 			iov.iov_len = piod->piod_len;
1191 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1192 			uio.uio_resid = piod->piod_len;
1193 		}
1194 		uio.uio_iov = &iov;
1195 		uio.uio_iovcnt = 1;
1196 		uio.uio_segflg = UIO_USERSPACE;
1197 		uio.uio_td = td;
1198 #ifdef COMPAT_FREEBSD32
1199 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1200 #else
1201 		tmp = piod->piod_op;
1202 #endif
1203 		switch (tmp) {
1204 		case PIOD_READ_D:
1205 		case PIOD_READ_I:
1206 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1207 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1208 			uio.uio_rw = UIO_READ;
1209 			break;
1210 		case PIOD_WRITE_D:
1211 		case PIOD_WRITE_I:
1212 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1213 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1214 			td2->td_dbgflags |= TDB_USERWR;
1215 			uio.uio_rw = UIO_WRITE;
1216 			break;
1217 		default:
1218 			error = EINVAL;
1219 			goto out;
1220 		}
1221 		PROC_UNLOCK(p);
1222 		error = proc_rwmem(p, &uio);
1223 #ifdef COMPAT_FREEBSD32
1224 		if (wrap32)
1225 			piod32->piod_len -= uio.uio_resid;
1226 		else
1227 #endif
1228 			piod->piod_len -= uio.uio_resid;
1229 		PROC_LOCK(p);
1230 		break;
1231 
1232 	case PT_KILL:
1233 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1234 		data = SIGKILL;
1235 		goto sendsig;	/* in PT_CONTINUE above */
1236 
1237 	case PT_SETREGS:
1238 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1239 		    p->p_pid);
1240 		td2->td_dbgflags |= TDB_USERWR;
1241 		error = PROC_WRITE(regs, td2, addr);
1242 		break;
1243 
1244 	case PT_GETREGS:
1245 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1246 		    p->p_pid);
1247 		error = PROC_READ(regs, td2, addr);
1248 		break;
1249 
1250 	case PT_SETFPREGS:
1251 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1252 		    p->p_pid);
1253 		td2->td_dbgflags |= TDB_USERWR;
1254 		error = PROC_WRITE(fpregs, td2, addr);
1255 		break;
1256 
1257 	case PT_GETFPREGS:
1258 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1259 		    p->p_pid);
1260 		error = PROC_READ(fpregs, td2, addr);
1261 		break;
1262 
1263 	case PT_SETDBREGS:
1264 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1265 		    p->p_pid);
1266 		td2->td_dbgflags |= TDB_USERWR;
1267 		error = PROC_WRITE(dbregs, td2, addr);
1268 		break;
1269 
1270 	case PT_GETDBREGS:
1271 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1272 		    p->p_pid);
1273 		error = PROC_READ(dbregs, td2, addr);
1274 		break;
1275 
1276 	case PT_LWPINFO:
1277 		if (data <= 0 ||
1278 #ifdef COMPAT_FREEBSD32
1279 		    (!wrap32 && data > sizeof(*pl)) ||
1280 		    (wrap32 && data > sizeof(*pl32))) {
1281 #else
1282 		    data > sizeof(*pl)) {
1283 #endif
1284 			error = EINVAL;
1285 			break;
1286 		}
1287 #ifdef COMPAT_FREEBSD32
1288 		if (wrap32) {
1289 			pl = &plr;
1290 			pl32 = addr;
1291 		} else
1292 #endif
1293 		pl = addr;
1294 		pl->pl_lwpid = td2->td_tid;
1295 		pl->pl_event = PL_EVENT_NONE;
1296 		pl->pl_flags = 0;
1297 		if (td2->td_dbgflags & TDB_XSIG) {
1298 			pl->pl_event = PL_EVENT_SIGNAL;
1299 			if (td2->td_dbgksi.ksi_signo != 0 &&
1300 #ifdef COMPAT_FREEBSD32
1301 			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1302 			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1303 			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1304 			    pl_siginfo) + sizeof(struct siginfo32)))
1305 #else
1306 			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1307 			    + sizeof(pl->pl_siginfo)
1308 #endif
1309 			){
1310 				pl->pl_flags |= PL_FLAG_SI;
1311 				pl->pl_siginfo = td2->td_dbgksi.ksi_info;
1312 			}
1313 		}
1314 		if ((pl->pl_flags & PL_FLAG_SI) == 0)
1315 			bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
1316 		if (td2->td_dbgflags & TDB_SCE)
1317 			pl->pl_flags |= PL_FLAG_SCE;
1318 		else if (td2->td_dbgflags & TDB_SCX)
1319 			pl->pl_flags |= PL_FLAG_SCX;
1320 		if (td2->td_dbgflags & TDB_EXEC)
1321 			pl->pl_flags |= PL_FLAG_EXEC;
1322 		if (td2->td_dbgflags & TDB_FORK) {
1323 			pl->pl_flags |= PL_FLAG_FORKED;
1324 			pl->pl_child_pid = td2->td_dbg_forked;
1325 			if (td2->td_dbgflags & TDB_VFORK)
1326 				pl->pl_flags |= PL_FLAG_VFORKED;
1327 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1328 		    TDB_VFORK)
1329 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1330 		if (td2->td_dbgflags & TDB_CHILD)
1331 			pl->pl_flags |= PL_FLAG_CHILD;
1332 		if (td2->td_dbgflags & TDB_BORN)
1333 			pl->pl_flags |= PL_FLAG_BORN;
1334 		if (td2->td_dbgflags & TDB_EXIT)
1335 			pl->pl_flags |= PL_FLAG_EXITED;
1336 		pl->pl_sigmask = td2->td_sigmask;
1337 		pl->pl_siglist = td2->td_siglist;
1338 		strcpy(pl->pl_tdname, td2->td_name);
1339 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1340 			pl->pl_syscall_code = td2->td_dbg_sc_code;
1341 			pl->pl_syscall_narg = td2->td_dbg_sc_narg;
1342 		} else {
1343 			pl->pl_syscall_code = 0;
1344 			pl->pl_syscall_narg = 0;
1345 		}
1346 #ifdef COMPAT_FREEBSD32
1347 		if (wrap32)
1348 			ptrace_lwpinfo_to32(pl, pl32);
1349 #endif
1350 		CTR6(KTR_PTRACE,
1351     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1352 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1353 		    pl->pl_child_pid, pl->pl_syscall_code);
1354 		break;
1355 
1356 	case PT_GETNUMLWPS:
1357 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1358 		    p->p_numthreads);
1359 		td->td_retval[0] = p->p_numthreads;
1360 		break;
1361 
1362 	case PT_GETLWPLIST:
1363 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1364 		    p->p_pid, data, p->p_numthreads);
1365 		if (data <= 0) {
1366 			error = EINVAL;
1367 			break;
1368 		}
1369 		num = imin(p->p_numthreads, data);
1370 		PROC_UNLOCK(p);
1371 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1372 		tmp = 0;
1373 		PROC_LOCK(p);
1374 		FOREACH_THREAD_IN_PROC(p, td2) {
1375 			if (tmp >= num)
1376 				break;
1377 			buf[tmp++] = td2->td_tid;
1378 		}
1379 		PROC_UNLOCK(p);
1380 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1381 		free(buf, M_TEMP);
1382 		if (!error)
1383 			td->td_retval[0] = tmp;
1384 		PROC_LOCK(p);
1385 		break;
1386 
1387 	case PT_VM_TIMESTAMP:
1388 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1389 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1390 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1391 		break;
1392 
1393 	case PT_VM_ENTRY:
1394 		PROC_UNLOCK(p);
1395 #ifdef COMPAT_FREEBSD32
1396 		if (wrap32)
1397 			error = ptrace_vm_entry32(td, p, addr);
1398 		else
1399 #endif
1400 		error = ptrace_vm_entry(td, p, addr);
1401 		PROC_LOCK(p);
1402 		break;
1403 
1404 	default:
1405 #ifdef __HAVE_PTRACE_MACHDEP
1406 		if (req >= PT_FIRSTMACH) {
1407 			PROC_UNLOCK(p);
1408 			error = cpu_ptrace(td2, req, addr, data);
1409 			PROC_LOCK(p);
1410 		} else
1411 #endif
1412 			/* Unknown request. */
1413 			error = EINVAL;
1414 		break;
1415 	}
1416 
1417 out:
1418 	/* Drop our hold on this process now that the request has completed. */
1419 	_PRELE(p);
1420 fail:
1421 	PROC_UNLOCK(p);
1422 	if (proctree_locked)
1423 		sx_xunlock(&proctree_lock);
1424 	return (error);
1425 }
1426 #undef PROC_READ
1427 #undef PROC_WRITE
1428 
1429 /*
1430  * Stop a process because of a debugging event;
1431  * stay stopped until p->p_step is cleared
1432  * (cleared by PIOCCONT in procfs).
1433  */
1434 void
1435 stopevent(struct proc *p, unsigned int event, unsigned int val)
1436 {
1437 
1438 	PROC_LOCK_ASSERT(p, MA_OWNED);
1439 	p->p_step = 1;
1440 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1441 	    val);
1442 	do {
1443 		if (event != S_EXIT)
1444 			p->p_xsig = val;
1445 		p->p_xthread = NULL;
1446 		p->p_stype = event;	/* Which event caused the stop? */
1447 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1448 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1449 	} while (p->p_step);
1450 }
1451