sys_process.c revision 304190
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: stable/10/sys/kern/sys_process.c 304190 2016-08-15 21:44:06Z kib $");
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/priv.h>
45#include <sys/proc.h>
46#include <sys/vnode.h>
47#include <sys/ptrace.h>
48#include <sys/rwlock.h>
49#include <sys/sx.h>
50#include <sys/malloc.h>
51#include <sys/signalvar.h>
52
53#include <machine/reg.h>
54
55#include <security/audit/audit.h>
56
57#include <vm/vm.h>
58#include <vm/pmap.h>
59#include <vm/vm_extern.h>
60#include <vm/vm_map.h>
61#include <vm/vm_kern.h>
62#include <vm/vm_object.h>
63#include <vm/vm_page.h>
64#include <vm/vm_param.h>
65
66#ifdef COMPAT_FREEBSD32
67#include <sys/procfs.h>
68#include <compat/freebsd32/freebsd32_signal.h>
69
70struct ptrace_io_desc32 {
71	int		piod_op;
72	uint32_t	piod_offs;
73	uint32_t	piod_addr;
74	uint32_t	piod_len;
75};
76
77struct ptrace_vm_entry32 {
78	int		pve_entry;
79	int		pve_timestamp;
80	uint32_t	pve_start;
81	uint32_t	pve_end;
82	uint32_t	pve_offset;
83	u_int		pve_prot;
84	u_int		pve_pathlen;
85	int32_t		pve_fileid;
86	u_int		pve_fsid;
87	uint32_t	pve_path;
88};
89
90struct ptrace_lwpinfo32 {
91	lwpid_t	pl_lwpid;	/* LWP described. */
92	int	pl_event;	/* Event that stopped the LWP. */
93	int	pl_flags;	/* LWP flags. */
94	sigset_t	pl_sigmask;	/* LWP signal mask */
95	sigset_t	pl_siglist;	/* LWP pending signal */
96	struct siginfo32 pl_siginfo;	/* siginfo for signal */
97	char	pl_tdname[MAXCOMLEN + 1];	/* LWP name. */
98	pid_t	pl_child_pid;		/* New child pid */
99	u_int		pl_syscall_code;
100	u_int		pl_syscall_narg;
101};
102
103#endif
104
105/*
106 * Functions implemented using PROC_ACTION():
107 *
108 * proc_read_regs(proc, regs)
109 *	Get the current user-visible register set from the process
110 *	and copy it into the regs structure (<machine/reg.h>).
111 *	The process is stopped at the time read_regs is called.
112 *
113 * proc_write_regs(proc, regs)
114 *	Update the current register set from the passed in regs
115 *	structure.  Take care to avoid clobbering special CPU
116 *	registers or privileged bits in the PSL.
117 *	Depending on the architecture this may have fix-up work to do,
118 *	especially if the IAR or PCW are modified.
119 *	The process is stopped at the time write_regs is called.
120 *
121 * proc_read_fpregs, proc_write_fpregs
122 *	deal with the floating point register set, otherwise as above.
123 *
124 * proc_read_dbregs, proc_write_dbregs
125 *	deal with the processor debug register set, otherwise as above.
126 *
127 * proc_sstep(proc)
128 *	Arrange for the process to trap after executing a single instruction.
129 */
130
131#define	PROC_ACTION(action) do {					\
132	int error;							\
133									\
134	PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);			\
135	if ((td->td_proc->p_flag & P_INMEM) == 0)			\
136		error = EIO;						\
137	else								\
138		error = (action);					\
139	return (error);							\
140} while(0)
141
142int
143proc_read_regs(struct thread *td, struct reg *regs)
144{
145
146	PROC_ACTION(fill_regs(td, regs));
147}
148
149int
150proc_write_regs(struct thread *td, struct reg *regs)
151{
152
153	PROC_ACTION(set_regs(td, regs));
154}
155
156int
157proc_read_dbregs(struct thread *td, struct dbreg *dbregs)
158{
159
160	PROC_ACTION(fill_dbregs(td, dbregs));
161}
162
163int
164proc_write_dbregs(struct thread *td, struct dbreg *dbregs)
165{
166
167	PROC_ACTION(set_dbregs(td, dbregs));
168}
169
170/*
171 * Ptrace doesn't support fpregs at all, and there are no security holes
172 * or translations for fpregs, so we can just copy them.
173 */
174int
175proc_read_fpregs(struct thread *td, struct fpreg *fpregs)
176{
177
178	PROC_ACTION(fill_fpregs(td, fpregs));
179}
180
181int
182proc_write_fpregs(struct thread *td, struct fpreg *fpregs)
183{
184
185	PROC_ACTION(set_fpregs(td, fpregs));
186}
187
188#ifdef COMPAT_FREEBSD32
189/* For 32 bit binaries, we need to expose the 32 bit regs layouts. */
190int
191proc_read_regs32(struct thread *td, struct reg32 *regs32)
192{
193
194	PROC_ACTION(fill_regs32(td, regs32));
195}
196
197int
198proc_write_regs32(struct thread *td, struct reg32 *regs32)
199{
200
201	PROC_ACTION(set_regs32(td, regs32));
202}
203
204int
205proc_read_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
206{
207
208	PROC_ACTION(fill_dbregs32(td, dbregs32));
209}
210
211int
212proc_write_dbregs32(struct thread *td, struct dbreg32 *dbregs32)
213{
214
215	PROC_ACTION(set_dbregs32(td, dbregs32));
216}
217
218int
219proc_read_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
220{
221
222	PROC_ACTION(fill_fpregs32(td, fpregs32));
223}
224
225int
226proc_write_fpregs32(struct thread *td, struct fpreg32 *fpregs32)
227{
228
229	PROC_ACTION(set_fpregs32(td, fpregs32));
230}
231#endif
232
233int
234proc_sstep(struct thread *td)
235{
236
237	PROC_ACTION(ptrace_single_step(td));
238}
239
240int
241proc_rwmem(struct proc *p, struct uio *uio)
242{
243	vm_map_t map;
244	vm_offset_t pageno;		/* page number */
245	vm_prot_t reqprot;
246	int error, fault_flags, page_offset, writing;
247
248	/*
249	 * Assert that someone has locked this vmspace.  (Should be
250	 * curthread but we can't assert that.)  This keeps the process
251	 * from exiting out from under us until this operation completes.
252	 */
253	KASSERT(p->p_lock >= 1, ("%s: process %p (pid %d) not held", __func__,
254	    p, p->p_pid));
255
256	/*
257	 * The map we want...
258	 */
259	map = &p->p_vmspace->vm_map;
260
261	/*
262	 * If we are writing, then we request vm_fault() to create a private
263	 * copy of each page.  Since these copies will not be writeable by the
264	 * process, we must explicity request that they be dirtied.
265	 */
266	writing = uio->uio_rw == UIO_WRITE;
267	reqprot = writing ? VM_PROT_COPY | VM_PROT_READ : VM_PROT_READ;
268	fault_flags = writing ? VM_FAULT_DIRTY : VM_FAULT_NORMAL;
269
270	/*
271	 * Only map in one page at a time.  We don't have to, but it
272	 * makes things easier.  This way is trivial - right?
273	 */
274	do {
275		vm_offset_t uva;
276		u_int len;
277		vm_page_t m;
278
279		uva = (vm_offset_t)uio->uio_offset;
280
281		/*
282		 * Get the page number of this segment.
283		 */
284		pageno = trunc_page(uva);
285		page_offset = uva - pageno;
286
287		/*
288		 * How many bytes to copy
289		 */
290		len = min(PAGE_SIZE - page_offset, uio->uio_resid);
291
292		/*
293		 * Fault and hold the page on behalf of the process.
294		 */
295		error = vm_fault_hold(map, pageno, reqprot, fault_flags, &m);
296		if (error != KERN_SUCCESS) {
297			if (error == KERN_RESOURCE_SHORTAGE)
298				error = ENOMEM;
299			else
300				error = EFAULT;
301			break;
302		}
303
304		/*
305		 * Now do the i/o move.
306		 */
307		error = uiomove_fromphys(&m, page_offset, len, uio);
308
309		/* Make the I-cache coherent for breakpoints. */
310		if (writing && error == 0) {
311			vm_map_lock_read(map);
312			if (vm_map_check_protection(map, pageno, pageno +
313			    PAGE_SIZE, VM_PROT_EXECUTE))
314				vm_sync_icache(map, uva, len);
315			vm_map_unlock_read(map);
316		}
317
318		/*
319		 * Release the page.
320		 */
321		vm_page_lock(m);
322		vm_page_unhold(m);
323		vm_page_unlock(m);
324
325	} while (error == 0 && uio->uio_resid > 0);
326
327	return (error);
328}
329
330static int
331ptrace_vm_entry(struct thread *td, struct proc *p, struct ptrace_vm_entry *pve)
332{
333	struct vattr vattr;
334	vm_map_t map;
335	vm_map_entry_t entry;
336	vm_object_t obj, tobj, lobj;
337	struct vmspace *vm;
338	struct vnode *vp;
339	char *freepath, *fullpath;
340	u_int pathlen;
341	int error, index;
342
343	error = 0;
344	obj = NULL;
345
346	vm = vmspace_acquire_ref(p);
347	map = &vm->vm_map;
348	vm_map_lock_read(map);
349
350	do {
351		entry = map->header.next;
352		index = 0;
353		while (index < pve->pve_entry && entry != &map->header) {
354			entry = entry->next;
355			index++;
356		}
357		if (index != pve->pve_entry) {
358			error = EINVAL;
359			break;
360		}
361		while (entry != &map->header &&
362		    (entry->eflags & MAP_ENTRY_IS_SUB_MAP) != 0) {
363			entry = entry->next;
364			index++;
365		}
366		if (entry == &map->header) {
367			error = ENOENT;
368			break;
369		}
370
371		/* We got an entry. */
372		pve->pve_entry = index + 1;
373		pve->pve_timestamp = map->timestamp;
374		pve->pve_start = entry->start;
375		pve->pve_end = entry->end - 1;
376		pve->pve_offset = entry->offset;
377		pve->pve_prot = entry->protection;
378
379		/* Backing object's path needed? */
380		if (pve->pve_pathlen == 0)
381			break;
382
383		pathlen = pve->pve_pathlen;
384		pve->pve_pathlen = 0;
385
386		obj = entry->object.vm_object;
387		if (obj != NULL)
388			VM_OBJECT_RLOCK(obj);
389	} while (0);
390
391	vm_map_unlock_read(map);
392
393	pve->pve_fsid = VNOVAL;
394	pve->pve_fileid = VNOVAL;
395
396	if (error == 0 && obj != NULL) {
397		lobj = obj;
398		for (tobj = obj; tobj != NULL; tobj = tobj->backing_object) {
399			if (tobj != obj)
400				VM_OBJECT_RLOCK(tobj);
401			if (lobj != obj)
402				VM_OBJECT_RUNLOCK(lobj);
403			lobj = tobj;
404			pve->pve_offset += tobj->backing_object_offset;
405		}
406		vp = vm_object_vnode(lobj);
407		if (vp != NULL)
408			vref(vp);
409		if (lobj != obj)
410			VM_OBJECT_RUNLOCK(lobj);
411		VM_OBJECT_RUNLOCK(obj);
412
413		if (vp != NULL) {
414			freepath = NULL;
415			fullpath = NULL;
416			vn_fullpath(td, vp, &fullpath, &freepath);
417			vn_lock(vp, LK_SHARED | LK_RETRY);
418			if (VOP_GETATTR(vp, &vattr, td->td_ucred) == 0) {
419				pve->pve_fileid = vattr.va_fileid;
420				pve->pve_fsid = vattr.va_fsid;
421			}
422			vput(vp);
423
424			if (fullpath != NULL) {
425				pve->pve_pathlen = strlen(fullpath) + 1;
426				if (pve->pve_pathlen <= pathlen) {
427					error = copyout(fullpath, pve->pve_path,
428					    pve->pve_pathlen);
429				} else
430					error = ENAMETOOLONG;
431			}
432			if (freepath != NULL)
433				free(freepath, M_TEMP);
434		}
435	}
436	vmspace_free(vm);
437	if (error == 0)
438		CTR3(KTR_PTRACE, "PT_VM_ENTRY: pid %d, entry %d, start %p",
439		    p->p_pid, pve->pve_entry, pve->pve_start);
440
441	return (error);
442}
443
444#ifdef COMPAT_FREEBSD32
445static int
446ptrace_vm_entry32(struct thread *td, struct proc *p,
447    struct ptrace_vm_entry32 *pve32)
448{
449	struct ptrace_vm_entry pve;
450	int error;
451
452	pve.pve_entry = pve32->pve_entry;
453	pve.pve_pathlen = pve32->pve_pathlen;
454	pve.pve_path = (void *)(uintptr_t)pve32->pve_path;
455
456	error = ptrace_vm_entry(td, p, &pve);
457	if (error == 0) {
458		pve32->pve_entry = pve.pve_entry;
459		pve32->pve_timestamp = pve.pve_timestamp;
460		pve32->pve_start = pve.pve_start;
461		pve32->pve_end = pve.pve_end;
462		pve32->pve_offset = pve.pve_offset;
463		pve32->pve_prot = pve.pve_prot;
464		pve32->pve_fileid = pve.pve_fileid;
465		pve32->pve_fsid = pve.pve_fsid;
466	}
467
468	pve32->pve_pathlen = pve.pve_pathlen;
469	return (error);
470}
471
472static void
473ptrace_lwpinfo_to32(const struct ptrace_lwpinfo *pl,
474    struct ptrace_lwpinfo32 *pl32)
475{
476
477	pl32->pl_lwpid = pl->pl_lwpid;
478	pl32->pl_event = pl->pl_event;
479	pl32->pl_flags = pl->pl_flags;
480	pl32->pl_sigmask = pl->pl_sigmask;
481	pl32->pl_siglist = pl->pl_siglist;
482	siginfo_to_siginfo32(&pl->pl_siginfo, &pl32->pl_siginfo);
483	strcpy(pl32->pl_tdname, pl->pl_tdname);
484	pl32->pl_child_pid = pl->pl_child_pid;
485	pl32->pl_syscall_code = pl->pl_syscall_code;
486	pl32->pl_syscall_narg = pl->pl_syscall_narg;
487}
488#endif /* COMPAT_FREEBSD32 */
489
490/*
491 * Process debugging system call.
492 */
493#ifndef _SYS_SYSPROTO_H_
494struct ptrace_args {
495	int	req;
496	pid_t	pid;
497	caddr_t	addr;
498	int	data;
499};
500#endif
501
502#ifdef COMPAT_FREEBSD32
503/*
504 * This CPP subterfuge is to try and reduce the number of ifdefs in
505 * the body of the code.
506 *   COPYIN(uap->addr, &r.reg, sizeof r.reg);
507 * becomes either:
508 *   copyin(uap->addr, &r.reg, sizeof r.reg);
509 * or
510 *   copyin(uap->addr, &r.reg32, sizeof r.reg32);
511 * .. except this is done at runtime.
512 */
513#define	COPYIN(u, k, s)		wrap32 ? \
514	copyin(u, k ## 32, s ## 32) : \
515	copyin(u, k, s)
516#define	COPYOUT(k, u, s)	wrap32 ? \
517	copyout(k ## 32, u, s ## 32) : \
518	copyout(k, u, s)
519#else
520#define	COPYIN(u, k, s)		copyin(u, k, s)
521#define	COPYOUT(k, u, s)	copyout(k, u, s)
522#endif
523int
524sys_ptrace(struct thread *td, struct ptrace_args *uap)
525{
526	/*
527	 * XXX this obfuscation is to reduce stack usage, but the register
528	 * structs may be too large to put on the stack anyway.
529	 */
530	union {
531		struct ptrace_io_desc piod;
532		struct ptrace_lwpinfo pl;
533		struct ptrace_vm_entry pve;
534		struct dbreg dbreg;
535		struct fpreg fpreg;
536		struct reg reg;
537#ifdef COMPAT_FREEBSD32
538		struct dbreg32 dbreg32;
539		struct fpreg32 fpreg32;
540		struct reg32 reg32;
541		struct ptrace_io_desc32 piod32;
542		struct ptrace_lwpinfo32 pl32;
543		struct ptrace_vm_entry32 pve32;
544#endif
545		int ptevents;
546	} r;
547	void *addr;
548	int error = 0;
549#ifdef COMPAT_FREEBSD32
550	int wrap32 = 0;
551
552	if (SV_CURPROC_FLAG(SV_ILP32))
553		wrap32 = 1;
554#endif
555	AUDIT_ARG_PID(uap->pid);
556	AUDIT_ARG_CMD(uap->req);
557	AUDIT_ARG_VALUE(uap->data);
558	addr = &r;
559	switch (uap->req) {
560	case PT_GET_EVENT_MASK:
561	case PT_GETREGS:
562	case PT_GETFPREGS:
563	case PT_GETDBREGS:
564	case PT_LWPINFO:
565		break;
566	case PT_SETREGS:
567		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
568		break;
569	case PT_SETFPREGS:
570		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
571		break;
572	case PT_SETDBREGS:
573		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
574		break;
575	case PT_SET_EVENT_MASK:
576		if (uap->data != sizeof(r.ptevents))
577			error = EINVAL;
578		else
579			error = copyin(uap->addr, &r.ptevents, uap->data);
580		break;
581	case PT_IO:
582		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
583		break;
584	case PT_VM_ENTRY:
585		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
586		break;
587	default:
588		addr = uap->addr;
589		break;
590	}
591	if (error)
592		return (error);
593
594	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
595	if (error)
596		return (error);
597
598	switch (uap->req) {
599	case PT_VM_ENTRY:
600		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
601		break;
602	case PT_IO:
603		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
604		break;
605	case PT_GETREGS:
606		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
607		break;
608	case PT_GETFPREGS:
609		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
610		break;
611	case PT_GETDBREGS:
612		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
613		break;
614	case PT_GET_EVENT_MASK:
615		/* NB: The size in uap->data is validated in kern_ptrace(). */
616		error = copyout(&r.ptevents, uap->addr, uap->data);
617		break;
618	case PT_LWPINFO:
619		/* NB: The size in uap->data is validated in kern_ptrace(). */
620		error = copyout(&r.pl, uap->addr, uap->data);
621		break;
622	}
623
624	return (error);
625}
626#undef COPYIN
627#undef COPYOUT
628
629#ifdef COMPAT_FREEBSD32
630/*
631 *   PROC_READ(regs, td2, addr);
632 * becomes either:
633 *   proc_read_regs(td2, addr);
634 * or
635 *   proc_read_regs32(td2, addr);
636 * .. except this is done at runtime.  There is an additional
637 * complication in that PROC_WRITE disallows 32 bit consumers
638 * from writing to 64 bit address space targets.
639 */
640#define	PROC_READ(w, t, a)	wrap32 ? \
641	proc_read_ ## w ## 32(t, a) : \
642	proc_read_ ## w (t, a)
643#define	PROC_WRITE(w, t, a)	wrap32 ? \
644	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
645	proc_write_ ## w (t, a)
646#else
647#define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
648#define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
649#endif
650
651void
652proc_set_traced(struct proc *p)
653{
654
655	PROC_LOCK_ASSERT(p, MA_OWNED);
656	p->p_flag |= P_TRACED;
657	p->p_flag2 |= P2_PTRACE_FSTP;
658	p->p_ptevents = PTRACE_DEFAULT;
659	p->p_oppid = p->p_pptr->p_pid;
660}
661
662int
663kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
664{
665	struct iovec iov;
666	struct uio uio;
667	struct proc *curp, *p, *pp;
668	struct thread *td2 = NULL, *td3;
669	struct ptrace_io_desc *piod = NULL;
670	struct ptrace_lwpinfo *pl;
671	int error, write, tmp, num;
672	int proctree_locked = 0;
673	lwpid_t tid = 0, *buf;
674#ifdef COMPAT_FREEBSD32
675	int wrap32 = 0, safe = 0;
676	struct ptrace_io_desc32 *piod32 = NULL;
677	struct ptrace_lwpinfo32 *pl32 = NULL;
678	struct ptrace_lwpinfo plr;
679#endif
680
681	curp = td->td_proc;
682
683	/* Lock proctree before locking the process. */
684	switch (req) {
685	case PT_TRACE_ME:
686	case PT_ATTACH:
687	case PT_STEP:
688	case PT_CONTINUE:
689	case PT_TO_SCE:
690	case PT_TO_SCX:
691	case PT_SYSCALL:
692	case PT_FOLLOW_FORK:
693	case PT_LWP_EVENTS:
694	case PT_GET_EVENT_MASK:
695	case PT_SET_EVENT_MASK:
696	case PT_DETACH:
697		sx_xlock(&proctree_lock);
698		proctree_locked = 1;
699		break;
700	default:
701		break;
702	}
703
704	write = 0;
705	if (req == PT_TRACE_ME) {
706		p = td->td_proc;
707		PROC_LOCK(p);
708	} else {
709		if (pid <= PID_MAX) {
710			if ((p = pfind(pid)) == NULL) {
711				if (proctree_locked)
712					sx_xunlock(&proctree_lock);
713				return (ESRCH);
714			}
715		} else {
716			td2 = tdfind(pid, -1);
717			if (td2 == NULL) {
718				if (proctree_locked)
719					sx_xunlock(&proctree_lock);
720				return (ESRCH);
721			}
722			p = td2->td_proc;
723			tid = pid;
724			pid = p->p_pid;
725		}
726	}
727	AUDIT_ARG_PROCESS(p);
728
729	if ((p->p_flag & P_WEXIT) != 0) {
730		error = ESRCH;
731		goto fail;
732	}
733	if ((error = p_cansee(td, p)) != 0)
734		goto fail;
735
736	if ((error = p_candebug(td, p)) != 0)
737		goto fail;
738
739	/*
740	 * System processes can't be debugged.
741	 */
742	if ((p->p_flag & P_SYSTEM) != 0) {
743		error = EINVAL;
744		goto fail;
745	}
746
747	if (tid == 0) {
748		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
749			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
750			td2 = p->p_xthread;
751		} else {
752			td2 = FIRST_THREAD_IN_PROC(p);
753		}
754		tid = td2->td_tid;
755	}
756
757#ifdef COMPAT_FREEBSD32
758	/*
759	 * Test if we're a 32 bit client and what the target is.
760	 * Set the wrap controls accordingly.
761	 */
762	if (SV_CURPROC_FLAG(SV_ILP32)) {
763		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
764			safe = 1;
765		wrap32 = 1;
766	}
767#endif
768	/*
769	 * Permissions check
770	 */
771	switch (req) {
772	case PT_TRACE_ME:
773		/*
774		 * Always legal, when there is a parent process which
775		 * could trace us.  Otherwise, reject.
776		 */
777		if ((p->p_flag & P_TRACED) != 0) {
778			error = EBUSY;
779			goto fail;
780		}
781		if (p->p_pptr == initproc) {
782			error = EPERM;
783			goto fail;
784		}
785		break;
786
787	case PT_ATTACH:
788		/* Self */
789		if (p == td->td_proc) {
790			error = EINVAL;
791			goto fail;
792		}
793
794		/* Already traced */
795		if (p->p_flag & P_TRACED) {
796			error = EBUSY;
797			goto fail;
798		}
799
800		/* Can't trace an ancestor if you're being traced. */
801		if (curp->p_flag & P_TRACED) {
802			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
803				if (pp == p) {
804					error = EINVAL;
805					goto fail;
806				}
807			}
808		}
809
810
811		/* OK */
812		break;
813
814	case PT_CLEARSTEP:
815		/* Allow thread to clear single step for itself */
816		if (td->td_tid == tid)
817			break;
818
819		/* FALLTHROUGH */
820	default:
821		/* not being traced... */
822		if ((p->p_flag & P_TRACED) == 0) {
823			error = EPERM;
824			goto fail;
825		}
826
827		/* not being traced by YOU */
828		if (p->p_pptr != td->td_proc) {
829			error = EBUSY;
830			goto fail;
831		}
832
833		/* not currently stopped */
834		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
835		    p->p_suspcount != p->p_numthreads  ||
836		    (p->p_flag & P_WAITED) == 0) {
837			error = EBUSY;
838			goto fail;
839		}
840
841		if ((p->p_flag & P_STOPPED_TRACE) == 0) {
842			static int count = 0;
843			if (count++ == 0)
844				printf("P_STOPPED_TRACE not set.\n");
845		}
846
847		/* OK */
848		break;
849	}
850
851	/* Keep this process around until we finish this request. */
852	_PHOLD(p);
853
854#ifdef FIX_SSTEP
855	/*
856	 * Single step fixup ala procfs
857	 */
858	FIX_SSTEP(td2);
859#endif
860
861	/*
862	 * Actually do the requests
863	 */
864
865	td->td_retval[0] = 0;
866
867	switch (req) {
868	case PT_TRACE_ME:
869		/* set my trace flag and "owner" so it can read/write me */
870		proc_set_traced(p);
871		if (p->p_flag & P_PPWAIT)
872			p->p_flag |= P_PPTRACE;
873		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
874		break;
875
876	case PT_ATTACH:
877		/* security check done above */
878		/*
879		 * It would be nice if the tracing relationship was separate
880		 * from the parent relationship but that would require
881		 * another set of links in the proc struct or for "wait"
882		 * to scan the entire proc table.  To make life easier,
883		 * we just re-parent the process we're trying to trace.
884		 * The old parent is remembered so we can put things back
885		 * on a "detach".
886		 */
887		proc_set_traced(p);
888		if (p->p_pptr != td->td_proc) {
889			proc_reparent(p, td->td_proc);
890		}
891		data = SIGSTOP;
892		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
893		    p->p_oppid);
894		goto sendsig;	/* in PT_CONTINUE below */
895
896	case PT_CLEARSTEP:
897		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
898		    p->p_pid);
899		error = ptrace_clear_single_step(td2);
900		break;
901
902	case PT_SETSTEP:
903		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
904		    p->p_pid);
905		error = ptrace_single_step(td2);
906		break;
907
908	case PT_SUSPEND:
909		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
910		    p->p_pid);
911		td2->td_dbgflags |= TDB_SUSPEND;
912		thread_lock(td2);
913		td2->td_flags |= TDF_NEEDSUSPCHK;
914		thread_unlock(td2);
915		break;
916
917	case PT_RESUME:
918		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
919		    p->p_pid);
920		td2->td_dbgflags &= ~TDB_SUSPEND;
921		break;
922
923	case PT_FOLLOW_FORK:
924		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
925		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
926		    data ? "enabled" : "disabled");
927		if (data)
928			p->p_ptevents |= PTRACE_FORK;
929		else
930			p->p_ptevents &= ~PTRACE_FORK;
931		break;
932
933	case PT_LWP_EVENTS:
934		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
935		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
936		    data ? "enabled" : "disabled");
937		if (data)
938			p->p_ptevents |= PTRACE_LWP;
939		else
940			p->p_ptevents &= ~PTRACE_LWP;
941		break;
942
943	case PT_GET_EVENT_MASK:
944		if (data != sizeof(p->p_ptevents)) {
945			error = EINVAL;
946			break;
947		}
948		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
949		    p->p_ptevents);
950		*(int *)addr = p->p_ptevents;
951		break;
952
953	case PT_SET_EVENT_MASK:
954		if (data != sizeof(p->p_ptevents)) {
955			error = EINVAL;
956			break;
957		}
958		tmp = *(int *)addr;
959		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
960		    PTRACE_FORK | PTRACE_LWP)) != 0) {
961			error = EINVAL;
962			break;
963		}
964		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
965		    p->p_pid, p->p_ptevents, tmp);
966		p->p_ptevents = tmp;
967		break;
968
969	case PT_STEP:
970	case PT_CONTINUE:
971	case PT_TO_SCE:
972	case PT_TO_SCX:
973	case PT_SYSCALL:
974	case PT_DETACH:
975		/* Zero means do not send any signal */
976		if (data < 0 || data > _SIG_MAXSIG) {
977			error = EINVAL;
978			break;
979		}
980
981		switch (req) {
982		case PT_STEP:
983			CTR2(KTR_PTRACE, "PT_STEP: tid %d (pid %d)",
984			    td2->td_tid, p->p_pid);
985			error = ptrace_single_step(td2);
986			if (error)
987				goto out;
988			break;
989		case PT_CONTINUE:
990		case PT_TO_SCE:
991		case PT_TO_SCX:
992		case PT_SYSCALL:
993			if (addr != (void *)1) {
994				error = ptrace_set_pc(td2,
995				    (u_long)(uintfptr_t)addr);
996				if (error)
997					goto out;
998			}
999			switch (req) {
1000			case PT_TO_SCE:
1001				p->p_ptevents |= PTRACE_SCE;
1002				CTR4(KTR_PTRACE,
1003		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1004				    p->p_pid, p->p_ptevents,
1005				    (u_long)(uintfptr_t)addr, data);
1006				break;
1007			case PT_TO_SCX:
1008				p->p_ptevents |= PTRACE_SCX;
1009				CTR4(KTR_PTRACE,
1010		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1011				    p->p_pid, p->p_ptevents,
1012				    (u_long)(uintfptr_t)addr, data);
1013				break;
1014			case PT_SYSCALL:
1015				p->p_ptevents |= PTRACE_SYSCALL;
1016				CTR4(KTR_PTRACE,
1017		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1018				    p->p_pid, p->p_ptevents,
1019				    (u_long)(uintfptr_t)addr, data);
1020				break;
1021			case PT_CONTINUE:
1022				CTR3(KTR_PTRACE,
1023				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1024				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1025				break;
1026			}
1027			break;
1028		case PT_DETACH:
1029			/*
1030			 * Reset the process parent.
1031			 *
1032			 * NB: This clears P_TRACED before reparenting
1033			 * a detached process back to its original
1034			 * parent.  Otherwise the debugee will be set
1035			 * as an orphan of the debugger.
1036			 */
1037			p->p_flag &= ~(P_TRACED | P_WAITED);
1038			if (p->p_oppid != p->p_pptr->p_pid) {
1039				PROC_LOCK(p->p_pptr);
1040				sigqueue_take(p->p_ksi);
1041				PROC_UNLOCK(p->p_pptr);
1042
1043				pp = proc_realparent(p);
1044				proc_reparent(p, pp);
1045				if (pp == initproc)
1046					p->p_sigparent = SIGCHLD;
1047				CTR3(KTR_PTRACE,
1048			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1049				    p->p_pid, pp->p_pid, data);
1050			} else
1051				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1052				    p->p_pid, data);
1053			p->p_oppid = 0;
1054			p->p_ptevents = 0;
1055			FOREACH_THREAD_IN_PROC(p, td3) {
1056				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1057					sigqueue_delete(&td3->td_sigqueue,
1058					    SIGSTOP);
1059				}
1060				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP);
1061			}
1062			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1063				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1064				p->p_flag2 &= ~P2_PTRACE_FSTP;
1065			}
1066
1067			/* should we send SIGCHLD? */
1068			/* childproc_continued(p); */
1069			break;
1070		}
1071
1072	sendsig:
1073		if (proctree_locked) {
1074			sx_xunlock(&proctree_lock);
1075			proctree_locked = 0;
1076		}
1077		p->p_xstat = data;
1078		p->p_xthread = NULL;
1079		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
1080			/* deliver or queue signal */
1081			td2->td_dbgflags &= ~TDB_XSIG;
1082			td2->td_xsig = data;
1083
1084			if (req == PT_DETACH) {
1085				FOREACH_THREAD_IN_PROC(p, td3)
1086					td3->td_dbgflags &= ~TDB_SUSPEND;
1087			}
1088			/*
1089			 * unsuspend all threads, to not let a thread run,
1090			 * you should use PT_SUSPEND to suspend it before
1091			 * continuing process.
1092			 */
1093			PROC_SLOCK(p);
1094			p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
1095			thread_unsuspend(p);
1096			PROC_SUNLOCK(p);
1097			if (req == PT_ATTACH)
1098				kern_psignal(p, data);
1099		} else {
1100			if (data)
1101				kern_psignal(p, data);
1102		}
1103		break;
1104
1105	case PT_WRITE_I:
1106	case PT_WRITE_D:
1107		td2->td_dbgflags |= TDB_USERWR;
1108		write = 1;
1109		/* FALLTHROUGH */
1110	case PT_READ_I:
1111	case PT_READ_D:
1112		PROC_UNLOCK(p);
1113		tmp = 0;
1114		/* write = 0 set above */
1115		iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
1116		iov.iov_len = sizeof(int);
1117		uio.uio_iov = &iov;
1118		uio.uio_iovcnt = 1;
1119		uio.uio_offset = (off_t)(uintptr_t)addr;
1120		uio.uio_resid = sizeof(int);
1121		uio.uio_segflg = UIO_SYSSPACE;	/* i.e.: the uap */
1122		uio.uio_rw = write ? UIO_WRITE : UIO_READ;
1123		uio.uio_td = td;
1124		error = proc_rwmem(p, &uio);
1125		if (uio.uio_resid != 0) {
1126			/*
1127			 * XXX proc_rwmem() doesn't currently return ENOSPC,
1128			 * so I think write() can bogusly return 0.
1129			 * XXX what happens for short writes?  We don't want
1130			 * to write partial data.
1131			 * XXX proc_rwmem() returns EPERM for other invalid
1132			 * addresses.  Convert this to EINVAL.  Does this
1133			 * clobber returns of EPERM for other reasons?
1134			 */
1135			if (error == 0 || error == ENOSPC || error == EPERM)
1136				error = EINVAL;	/* EOF */
1137		}
1138		if (!write)
1139			td->td_retval[0] = tmp;
1140		if (error == 0) {
1141			if (write)
1142				CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1143				    p->p_pid, addr, data);
1144			else
1145				CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1146				    p->p_pid, addr, tmp);
1147		}
1148		PROC_LOCK(p);
1149		break;
1150
1151	case PT_IO:
1152#ifdef COMPAT_FREEBSD32
1153		if (wrap32) {
1154			piod32 = addr;
1155			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1156			iov.iov_len = piod32->piod_len;
1157			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1158			uio.uio_resid = piod32->piod_len;
1159		} else
1160#endif
1161		{
1162			piod = addr;
1163			iov.iov_base = piod->piod_addr;
1164			iov.iov_len = piod->piod_len;
1165			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1166			uio.uio_resid = piod->piod_len;
1167		}
1168		uio.uio_iov = &iov;
1169		uio.uio_iovcnt = 1;
1170		uio.uio_segflg = UIO_USERSPACE;
1171		uio.uio_td = td;
1172#ifdef COMPAT_FREEBSD32
1173		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1174#else
1175		tmp = piod->piod_op;
1176#endif
1177		switch (tmp) {
1178		case PIOD_READ_D:
1179		case PIOD_READ_I:
1180			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1181			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1182			uio.uio_rw = UIO_READ;
1183			break;
1184		case PIOD_WRITE_D:
1185		case PIOD_WRITE_I:
1186			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1187			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1188			td2->td_dbgflags |= TDB_USERWR;
1189			uio.uio_rw = UIO_WRITE;
1190			break;
1191		default:
1192			error = EINVAL;
1193			goto out;
1194		}
1195		PROC_UNLOCK(p);
1196		error = proc_rwmem(p, &uio);
1197#ifdef COMPAT_FREEBSD32
1198		if (wrap32)
1199			piod32->piod_len -= uio.uio_resid;
1200		else
1201#endif
1202			piod->piod_len -= uio.uio_resid;
1203		PROC_LOCK(p);
1204		break;
1205
1206	case PT_KILL:
1207		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1208		data = SIGKILL;
1209		goto sendsig;	/* in PT_CONTINUE above */
1210
1211	case PT_SETREGS:
1212		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1213		    p->p_pid);
1214		td2->td_dbgflags |= TDB_USERWR;
1215		error = PROC_WRITE(regs, td2, addr);
1216		break;
1217
1218	case PT_GETREGS:
1219		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1220		    p->p_pid);
1221		error = PROC_READ(regs, td2, addr);
1222		break;
1223
1224	case PT_SETFPREGS:
1225		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1226		    p->p_pid);
1227		td2->td_dbgflags |= TDB_USERWR;
1228		error = PROC_WRITE(fpregs, td2, addr);
1229		break;
1230
1231	case PT_GETFPREGS:
1232		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1233		    p->p_pid);
1234		error = PROC_READ(fpregs, td2, addr);
1235		break;
1236
1237	case PT_SETDBREGS:
1238		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1239		    p->p_pid);
1240		td2->td_dbgflags |= TDB_USERWR;
1241		error = PROC_WRITE(dbregs, td2, addr);
1242		break;
1243
1244	case PT_GETDBREGS:
1245		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1246		    p->p_pid);
1247		error = PROC_READ(dbregs, td2, addr);
1248		break;
1249
1250	case PT_LWPINFO:
1251		if (data <= 0 ||
1252#ifdef COMPAT_FREEBSD32
1253		    (!wrap32 && data > sizeof(*pl)) ||
1254		    (wrap32 && data > sizeof(*pl32))) {
1255#else
1256		    data > sizeof(*pl)) {
1257#endif
1258			error = EINVAL;
1259			break;
1260		}
1261#ifdef COMPAT_FREEBSD32
1262		if (wrap32) {
1263			pl = &plr;
1264			pl32 = addr;
1265		} else
1266#endif
1267		pl = addr;
1268		pl->pl_lwpid = td2->td_tid;
1269		pl->pl_event = PL_EVENT_NONE;
1270		pl->pl_flags = 0;
1271		if (td2->td_dbgflags & TDB_XSIG) {
1272			pl->pl_event = PL_EVENT_SIGNAL;
1273			if (td2->td_dbgksi.ksi_signo != 0 &&
1274#ifdef COMPAT_FREEBSD32
1275			    ((!wrap32 && data >= offsetof(struct ptrace_lwpinfo,
1276			    pl_siginfo) + sizeof(pl->pl_siginfo)) ||
1277			    (wrap32 && data >= offsetof(struct ptrace_lwpinfo32,
1278			    pl_siginfo) + sizeof(struct siginfo32)))
1279#else
1280			    data >= offsetof(struct ptrace_lwpinfo, pl_siginfo)
1281			    + sizeof(pl->pl_siginfo)
1282#endif
1283			){
1284				pl->pl_flags |= PL_FLAG_SI;
1285				pl->pl_siginfo = td2->td_dbgksi.ksi_info;
1286			}
1287		}
1288		if ((pl->pl_flags & PL_FLAG_SI) == 0)
1289			bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
1290		if (td2->td_dbgflags & TDB_SCE)
1291			pl->pl_flags |= PL_FLAG_SCE;
1292		else if (td2->td_dbgflags & TDB_SCX)
1293			pl->pl_flags |= PL_FLAG_SCX;
1294		if (td2->td_dbgflags & TDB_EXEC)
1295			pl->pl_flags |= PL_FLAG_EXEC;
1296		if (td2->td_dbgflags & TDB_FORK) {
1297			pl->pl_flags |= PL_FLAG_FORKED;
1298			pl->pl_child_pid = td2->td_dbg_forked;
1299		}
1300		if (td2->td_dbgflags & TDB_CHILD)
1301			pl->pl_flags |= PL_FLAG_CHILD;
1302		if (td2->td_dbgflags & TDB_BORN)
1303			pl->pl_flags |= PL_FLAG_BORN;
1304		if (td2->td_dbgflags & TDB_EXIT)
1305			pl->pl_flags |= PL_FLAG_EXITED;
1306		pl->pl_sigmask = td2->td_sigmask;
1307		pl->pl_siglist = td2->td_siglist;
1308		strcpy(pl->pl_tdname, td2->td_name);
1309		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1310			pl->pl_syscall_code = td2->td_dbg_sc_code;
1311			pl->pl_syscall_narg = td2->td_dbg_sc_narg;
1312		} else {
1313			pl->pl_syscall_code = 0;
1314			pl->pl_syscall_narg = 0;
1315		}
1316#ifdef COMPAT_FREEBSD32
1317		if (wrap32)
1318			ptrace_lwpinfo_to32(pl, pl32);
1319#endif
1320		CTR6(KTR_PTRACE,
1321    "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1322		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1323		    pl->pl_child_pid, pl->pl_syscall_code);
1324		break;
1325
1326	case PT_GETNUMLWPS:
1327		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1328		    p->p_numthreads);
1329		td->td_retval[0] = p->p_numthreads;
1330		break;
1331
1332	case PT_GETLWPLIST:
1333		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1334		    p->p_pid, data, p->p_numthreads);
1335		if (data <= 0) {
1336			error = EINVAL;
1337			break;
1338		}
1339		num = imin(p->p_numthreads, data);
1340		PROC_UNLOCK(p);
1341		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1342		tmp = 0;
1343		PROC_LOCK(p);
1344		FOREACH_THREAD_IN_PROC(p, td2) {
1345			if (tmp >= num)
1346				break;
1347			buf[tmp++] = td2->td_tid;
1348		}
1349		PROC_UNLOCK(p);
1350		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1351		free(buf, M_TEMP);
1352		if (!error)
1353			td->td_retval[0] = tmp;
1354		PROC_LOCK(p);
1355		break;
1356
1357	case PT_VM_TIMESTAMP:
1358		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1359		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1360		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1361		break;
1362
1363	case PT_VM_ENTRY:
1364		PROC_UNLOCK(p);
1365#ifdef COMPAT_FREEBSD32
1366		if (wrap32)
1367			error = ptrace_vm_entry32(td, p, addr);
1368		else
1369#endif
1370		error = ptrace_vm_entry(td, p, addr);
1371		PROC_LOCK(p);
1372		break;
1373
1374	default:
1375#ifdef __HAVE_PTRACE_MACHDEP
1376		if (req >= PT_FIRSTMACH) {
1377			PROC_UNLOCK(p);
1378			error = cpu_ptrace(td2, req, addr, data);
1379			PROC_LOCK(p);
1380		} else
1381#endif
1382			/* Unknown request. */
1383			error = EINVAL;
1384		break;
1385	}
1386
1387out:
1388	/* Drop our hold on this process now that the request has completed. */
1389	_PRELE(p);
1390fail:
1391	PROC_UNLOCK(p);
1392	if (proctree_locked)
1393		sx_xunlock(&proctree_lock);
1394	return (error);
1395}
1396#undef PROC_READ
1397#undef PROC_WRITE
1398
1399/*
1400 * Stop a process because of a debugging event;
1401 * stay stopped until p->p_step is cleared
1402 * (cleared by PIOCCONT in procfs).
1403 */
1404void
1405stopevent(struct proc *p, unsigned int event, unsigned int val)
1406{
1407
1408	PROC_LOCK_ASSERT(p, MA_OWNED);
1409	p->p_step = 1;
1410	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1411	    val);
1412	do {
1413		p->p_xstat = val;
1414		p->p_xthread = NULL;
1415		p->p_stype = event;	/* Which event caused the stop? */
1416		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1417		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1418	} while (p->p_step);
1419}
1420