xref: /freebsd/sys/kern/sys_process.c (revision c99b67a7947ea215f9c1d44ec022680e98920cd1)
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 		char args[nitems(td->td_sa.args) * sizeof(register_t)];
590 		int ptevents;
591 	} r;
592 	void *addr;
593 	int error = 0;
594 #ifdef COMPAT_FREEBSD32
595 	int wrap32 = 0;
596 
597 	if (SV_CURPROC_FLAG(SV_ILP32))
598 		wrap32 = 1;
599 #endif
600 	AUDIT_ARG_PID(uap->pid);
601 	AUDIT_ARG_CMD(uap->req);
602 	AUDIT_ARG_VALUE(uap->data);
603 	addr = &r;
604 	switch (uap->req) {
605 	case PT_GET_EVENT_MASK:
606 	case PT_GETREGS:
607 	case PT_GETFPREGS:
608 	case PT_GETDBREGS:
609 	case PT_LWPINFO:
610 	case PT_GET_SC_ARGS:
611 		break;
612 	case PT_SETREGS:
613 		error = COPYIN(uap->addr, &r.reg, sizeof r.reg);
614 		break;
615 	case PT_SETFPREGS:
616 		error = COPYIN(uap->addr, &r.fpreg, sizeof r.fpreg);
617 		break;
618 	case PT_SETDBREGS:
619 		error = COPYIN(uap->addr, &r.dbreg, sizeof r.dbreg);
620 		break;
621 	case PT_SET_EVENT_MASK:
622 		if (uap->data != sizeof(r.ptevents))
623 			error = EINVAL;
624 		else
625 			error = copyin(uap->addr, &r.ptevents, uap->data);
626 		break;
627 	case PT_IO:
628 		error = COPYIN(uap->addr, &r.piod, sizeof r.piod);
629 		break;
630 	case PT_VM_ENTRY:
631 		error = COPYIN(uap->addr, &r.pve, sizeof r.pve);
632 		break;
633 	default:
634 		addr = uap->addr;
635 		break;
636 	}
637 	if (error)
638 		return (error);
639 
640 	error = kern_ptrace(td, uap->req, uap->pid, addr, uap->data);
641 	if (error)
642 		return (error);
643 
644 	switch (uap->req) {
645 	case PT_VM_ENTRY:
646 		error = COPYOUT(&r.pve, uap->addr, sizeof r.pve);
647 		break;
648 	case PT_IO:
649 		error = COPYOUT(&r.piod, uap->addr, sizeof r.piod);
650 		break;
651 	case PT_GETREGS:
652 		error = COPYOUT(&r.reg, uap->addr, sizeof r.reg);
653 		break;
654 	case PT_GETFPREGS:
655 		error = COPYOUT(&r.fpreg, uap->addr, sizeof r.fpreg);
656 		break;
657 	case PT_GETDBREGS:
658 		error = COPYOUT(&r.dbreg, uap->addr, sizeof r.dbreg);
659 		break;
660 	case PT_GET_EVENT_MASK:
661 		/* NB: The size in uap->data is validated in kern_ptrace(). */
662 		error = copyout(&r.ptevents, uap->addr, uap->data);
663 		break;
664 	case PT_LWPINFO:
665 		/* NB: The size in uap->data is validated in kern_ptrace(). */
666 		error = copyout(&r.pl, uap->addr, uap->data);
667 		break;
668 	case PT_GET_SC_ARGS:
669 		error = copyout(r.args, uap->addr, MIN(uap->data,
670 		    sizeof(r.args)));
671 		break;
672 	}
673 
674 	return (error);
675 }
676 #undef COPYIN
677 #undef COPYOUT
678 
679 #ifdef COMPAT_FREEBSD32
680 /*
681  *   PROC_READ(regs, td2, addr);
682  * becomes either:
683  *   proc_read_regs(td2, addr);
684  * or
685  *   proc_read_regs32(td2, addr);
686  * .. except this is done at runtime.  There is an additional
687  * complication in that PROC_WRITE disallows 32 bit consumers
688  * from writing to 64 bit address space targets.
689  */
690 #define	PROC_READ(w, t, a)	wrap32 ? \
691 	proc_read_ ## w ## 32(t, a) : \
692 	proc_read_ ## w (t, a)
693 #define	PROC_WRITE(w, t, a)	wrap32 ? \
694 	(safe ? proc_write_ ## w ## 32(t, a) : EINVAL ) : \
695 	proc_write_ ## w (t, a)
696 #else
697 #define	PROC_READ(w, t, a)	proc_read_ ## w (t, a)
698 #define	PROC_WRITE(w, t, a)	proc_write_ ## w (t, a)
699 #endif
700 
701 void
702 proc_set_traced(struct proc *p, bool stop)
703 {
704 
705 	PROC_LOCK_ASSERT(p, MA_OWNED);
706 	p->p_flag |= P_TRACED;
707 	if (stop)
708 		p->p_flag2 |= P2_PTRACE_FSTP;
709 	p->p_ptevents = PTRACE_DEFAULT;
710 	p->p_oppid = p->p_pptr->p_pid;
711 }
712 
713 int
714 kern_ptrace(struct thread *td, int req, pid_t pid, void *addr, int data)
715 {
716 	struct iovec iov;
717 	struct uio uio;
718 	struct proc *curp, *p, *pp;
719 	struct thread *td2 = NULL, *td3;
720 	struct ptrace_io_desc *piod = NULL;
721 	struct ptrace_lwpinfo *pl;
722 	int error, num, tmp;
723 	int proctree_locked = 0;
724 	lwpid_t tid = 0, *buf;
725 #ifdef COMPAT_FREEBSD32
726 	int wrap32 = 0, safe = 0;
727 	struct ptrace_io_desc32 *piod32 = NULL;
728 	struct ptrace_lwpinfo32 *pl32 = NULL;
729 	struct ptrace_lwpinfo plr;
730 #endif
731 
732 	curp = td->td_proc;
733 
734 	/* Lock proctree before locking the process. */
735 	switch (req) {
736 	case PT_TRACE_ME:
737 	case PT_ATTACH:
738 	case PT_STEP:
739 	case PT_CONTINUE:
740 	case PT_TO_SCE:
741 	case PT_TO_SCX:
742 	case PT_SYSCALL:
743 	case PT_FOLLOW_FORK:
744 	case PT_LWP_EVENTS:
745 	case PT_GET_EVENT_MASK:
746 	case PT_SET_EVENT_MASK:
747 	case PT_DETACH:
748 	case PT_GET_SC_ARGS:
749 		sx_xlock(&proctree_lock);
750 		proctree_locked = 1;
751 		break;
752 	default:
753 		break;
754 	}
755 
756 	if (req == PT_TRACE_ME) {
757 		p = td->td_proc;
758 		PROC_LOCK(p);
759 	} else {
760 		if (pid <= PID_MAX) {
761 			if ((p = pfind(pid)) == NULL) {
762 				if (proctree_locked)
763 					sx_xunlock(&proctree_lock);
764 				return (ESRCH);
765 			}
766 		} else {
767 			td2 = tdfind(pid, -1);
768 			if (td2 == NULL) {
769 				if (proctree_locked)
770 					sx_xunlock(&proctree_lock);
771 				return (ESRCH);
772 			}
773 			p = td2->td_proc;
774 			tid = pid;
775 			pid = p->p_pid;
776 		}
777 	}
778 	AUDIT_ARG_PROCESS(p);
779 
780 	if ((p->p_flag & P_WEXIT) != 0) {
781 		error = ESRCH;
782 		goto fail;
783 	}
784 	if ((error = p_cansee(td, p)) != 0)
785 		goto fail;
786 
787 	if ((error = p_candebug(td, p)) != 0)
788 		goto fail;
789 
790 	/*
791 	 * System processes can't be debugged.
792 	 */
793 	if ((p->p_flag & P_SYSTEM) != 0) {
794 		error = EINVAL;
795 		goto fail;
796 	}
797 
798 	if (tid == 0) {
799 		if ((p->p_flag & P_STOPPED_TRACE) != 0) {
800 			KASSERT(p->p_xthread != NULL, ("NULL p_xthread"));
801 			td2 = p->p_xthread;
802 		} else {
803 			td2 = FIRST_THREAD_IN_PROC(p);
804 		}
805 		tid = td2->td_tid;
806 	}
807 
808 #ifdef COMPAT_FREEBSD32
809 	/*
810 	 * Test if we're a 32 bit client and what the target is.
811 	 * Set the wrap controls accordingly.
812 	 */
813 	if (SV_CURPROC_FLAG(SV_ILP32)) {
814 		if (SV_PROC_FLAG(td2->td_proc, SV_ILP32))
815 			safe = 1;
816 		wrap32 = 1;
817 	}
818 #endif
819 	/*
820 	 * Permissions check
821 	 */
822 	switch (req) {
823 	case PT_TRACE_ME:
824 		/*
825 		 * Always legal, when there is a parent process which
826 		 * could trace us.  Otherwise, reject.
827 		 */
828 		if ((p->p_flag & P_TRACED) != 0) {
829 			error = EBUSY;
830 			goto fail;
831 		}
832 		if (p->p_pptr == initproc) {
833 			error = EPERM;
834 			goto fail;
835 		}
836 		break;
837 
838 	case PT_ATTACH:
839 		/* Self */
840 		if (p == td->td_proc) {
841 			error = EINVAL;
842 			goto fail;
843 		}
844 
845 		/* Already traced */
846 		if (p->p_flag & P_TRACED) {
847 			error = EBUSY;
848 			goto fail;
849 		}
850 
851 		/* Can't trace an ancestor if you're being traced. */
852 		if (curp->p_flag & P_TRACED) {
853 			for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) {
854 				if (pp == p) {
855 					error = EINVAL;
856 					goto fail;
857 				}
858 			}
859 		}
860 
861 
862 		/* OK */
863 		break;
864 
865 	case PT_CLEARSTEP:
866 		/* Allow thread to clear single step for itself */
867 		if (td->td_tid == tid)
868 			break;
869 
870 		/* FALLTHROUGH */
871 	default:
872 		/* not being traced... */
873 		if ((p->p_flag & P_TRACED) == 0) {
874 			error = EPERM;
875 			goto fail;
876 		}
877 
878 		/* not being traced by YOU */
879 		if (p->p_pptr != td->td_proc) {
880 			error = EBUSY;
881 			goto fail;
882 		}
883 
884 		/* not currently stopped */
885 		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) == 0 ||
886 		    p->p_suspcount != p->p_numthreads  ||
887 		    (p->p_flag & P_WAITED) == 0) {
888 			error = EBUSY;
889 			goto fail;
890 		}
891 
892 		if ((p->p_flag & P_STOPPED_TRACE) == 0) {
893 			static int count = 0;
894 			if (count++ == 0)
895 				printf("P_STOPPED_TRACE not set.\n");
896 		}
897 
898 		/* OK */
899 		break;
900 	}
901 
902 	/* Keep this process around until we finish this request. */
903 	_PHOLD(p);
904 
905 #ifdef FIX_SSTEP
906 	/*
907 	 * Single step fixup ala procfs
908 	 */
909 	FIX_SSTEP(td2);
910 #endif
911 
912 	/*
913 	 * Actually do the requests
914 	 */
915 
916 	td->td_retval[0] = 0;
917 
918 	switch (req) {
919 	case PT_TRACE_ME:
920 		/* set my trace flag and "owner" so it can read/write me */
921 		proc_set_traced(p, false);
922 		if (p->p_flag & P_PPWAIT)
923 			p->p_flag |= P_PPTRACE;
924 		CTR1(KTR_PTRACE, "PT_TRACE_ME: pid %d", p->p_pid);
925 		break;
926 
927 	case PT_ATTACH:
928 		/* security check done above */
929 		/*
930 		 * It would be nice if the tracing relationship was separate
931 		 * from the parent relationship but that would require
932 		 * another set of links in the proc struct or for "wait"
933 		 * to scan the entire proc table.  To make life easier,
934 		 * we just re-parent the process we're trying to trace.
935 		 * The old parent is remembered so we can put things back
936 		 * on a "detach".
937 		 */
938 		proc_set_traced(p, true);
939 		if (p->p_pptr != td->td_proc) {
940 			proc_reparent(p, td->td_proc);
941 		}
942 		data = SIGSTOP;
943 		CTR2(KTR_PTRACE, "PT_ATTACH: pid %d, oppid %d", p->p_pid,
944 		    p->p_oppid);
945 		goto sendsig;	/* in PT_CONTINUE below */
946 
947 	case PT_CLEARSTEP:
948 		CTR2(KTR_PTRACE, "PT_CLEARSTEP: tid %d (pid %d)", td2->td_tid,
949 		    p->p_pid);
950 		error = ptrace_clear_single_step(td2);
951 		break;
952 
953 	case PT_SETSTEP:
954 		CTR2(KTR_PTRACE, "PT_SETSTEP: tid %d (pid %d)", td2->td_tid,
955 		    p->p_pid);
956 		error = ptrace_single_step(td2);
957 		break;
958 
959 	case PT_SUSPEND:
960 		CTR2(KTR_PTRACE, "PT_SUSPEND: tid %d (pid %d)", td2->td_tid,
961 		    p->p_pid);
962 		td2->td_dbgflags |= TDB_SUSPEND;
963 		thread_lock(td2);
964 		td2->td_flags |= TDF_NEEDSUSPCHK;
965 		thread_unlock(td2);
966 		break;
967 
968 	case PT_RESUME:
969 		CTR2(KTR_PTRACE, "PT_RESUME: tid %d (pid %d)", td2->td_tid,
970 		    p->p_pid);
971 		td2->td_dbgflags &= ~TDB_SUSPEND;
972 		break;
973 
974 	case PT_FOLLOW_FORK:
975 		CTR3(KTR_PTRACE, "PT_FOLLOW_FORK: pid %d %s -> %s", p->p_pid,
976 		    p->p_ptevents & PTRACE_FORK ? "enabled" : "disabled",
977 		    data ? "enabled" : "disabled");
978 		if (data)
979 			p->p_ptevents |= PTRACE_FORK;
980 		else
981 			p->p_ptevents &= ~PTRACE_FORK;
982 		break;
983 
984 	case PT_LWP_EVENTS:
985 		CTR3(KTR_PTRACE, "PT_LWP_EVENTS: pid %d %s -> %s", p->p_pid,
986 		    p->p_ptevents & PTRACE_LWP ? "enabled" : "disabled",
987 		    data ? "enabled" : "disabled");
988 		if (data)
989 			p->p_ptevents |= PTRACE_LWP;
990 		else
991 			p->p_ptevents &= ~PTRACE_LWP;
992 		break;
993 
994 	case PT_GET_EVENT_MASK:
995 		if (data != sizeof(p->p_ptevents)) {
996 			error = EINVAL;
997 			break;
998 		}
999 		CTR2(KTR_PTRACE, "PT_GET_EVENT_MASK: pid %d mask %#x", p->p_pid,
1000 		    p->p_ptevents);
1001 		*(int *)addr = p->p_ptevents;
1002 		break;
1003 
1004 	case PT_SET_EVENT_MASK:
1005 		if (data != sizeof(p->p_ptevents)) {
1006 			error = EINVAL;
1007 			break;
1008 		}
1009 		tmp = *(int *)addr;
1010 		if ((tmp & ~(PTRACE_EXEC | PTRACE_SCE | PTRACE_SCX |
1011 		    PTRACE_FORK | PTRACE_LWP | PTRACE_VFORK)) != 0) {
1012 			error = EINVAL;
1013 			break;
1014 		}
1015 		CTR3(KTR_PTRACE, "PT_SET_EVENT_MASK: pid %d mask %#x -> %#x",
1016 		    p->p_pid, p->p_ptevents, tmp);
1017 		p->p_ptevents = tmp;
1018 		break;
1019 
1020 	case PT_GET_SC_ARGS:
1021 		CTR1(KTR_PTRACE, "PT_GET_SC_ARGS: pid %d", p->p_pid);
1022 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) == 0
1023 #ifdef COMPAT_FREEBSD32
1024 		    || (wrap32 && !safe)
1025 #endif
1026 		    ) {
1027 			error = EINVAL;
1028 			break;
1029 		}
1030 		bzero(addr, sizeof(td2->td_sa.args));
1031 #ifdef COMPAT_FREEBSD32
1032 		if (wrap32)
1033 			for (num = 0; num < nitems(td2->td_sa.args); num++)
1034 				((uint32_t *)addr)[num] = (uint32_t)
1035 				    td2->td_sa.args[num];
1036 		else
1037 #endif
1038 			bcopy(td2->td_sa.args, addr, td2->td_sa.narg *
1039 			    sizeof(register_t));
1040 		break;
1041 
1042 	case PT_STEP:
1043 	case PT_CONTINUE:
1044 	case PT_TO_SCE:
1045 	case PT_TO_SCX:
1046 	case PT_SYSCALL:
1047 	case PT_DETACH:
1048 		/* Zero means do not send any signal */
1049 		if (data < 0 || data > _SIG_MAXSIG) {
1050 			error = EINVAL;
1051 			break;
1052 		}
1053 
1054 		switch (req) {
1055 		case PT_STEP:
1056 			CTR2(KTR_PTRACE, "PT_STEP: tid %d (pid %d)",
1057 			    td2->td_tid, p->p_pid);
1058 			error = ptrace_single_step(td2);
1059 			if (error)
1060 				goto out;
1061 			break;
1062 		case PT_CONTINUE:
1063 		case PT_TO_SCE:
1064 		case PT_TO_SCX:
1065 		case PT_SYSCALL:
1066 			if (addr != (void *)1) {
1067 				error = ptrace_set_pc(td2,
1068 				    (u_long)(uintfptr_t)addr);
1069 				if (error)
1070 					goto out;
1071 			}
1072 			switch (req) {
1073 			case PT_TO_SCE:
1074 				p->p_ptevents |= PTRACE_SCE;
1075 				CTR4(KTR_PTRACE,
1076 		    "PT_TO_SCE: pid %d, events = %#x, PC = %#lx, sig = %d",
1077 				    p->p_pid, p->p_ptevents,
1078 				    (u_long)(uintfptr_t)addr, data);
1079 				break;
1080 			case PT_TO_SCX:
1081 				p->p_ptevents |= PTRACE_SCX;
1082 				CTR4(KTR_PTRACE,
1083 		    "PT_TO_SCX: pid %d, events = %#x, PC = %#lx, sig = %d",
1084 				    p->p_pid, p->p_ptevents,
1085 				    (u_long)(uintfptr_t)addr, data);
1086 				break;
1087 			case PT_SYSCALL:
1088 				p->p_ptevents |= PTRACE_SYSCALL;
1089 				CTR4(KTR_PTRACE,
1090 		    "PT_SYSCALL: pid %d, events = %#x, PC = %#lx, sig = %d",
1091 				    p->p_pid, p->p_ptevents,
1092 				    (u_long)(uintfptr_t)addr, data);
1093 				break;
1094 			case PT_CONTINUE:
1095 				CTR3(KTR_PTRACE,
1096 				    "PT_CONTINUE: pid %d, PC = %#lx, sig = %d",
1097 				    p->p_pid, (u_long)(uintfptr_t)addr, data);
1098 				break;
1099 			}
1100 			break;
1101 		case PT_DETACH:
1102 			/*
1103 			 * Reset the process parent.
1104 			 *
1105 			 * NB: This clears P_TRACED before reparenting
1106 			 * a detached process back to its original
1107 			 * parent.  Otherwise the debugee will be set
1108 			 * as an orphan of the debugger.
1109 			 */
1110 			p->p_flag &= ~(P_TRACED | P_WAITED);
1111 			if (p->p_oppid != p->p_pptr->p_pid) {
1112 				PROC_LOCK(p->p_pptr);
1113 				sigqueue_take(p->p_ksi);
1114 				PROC_UNLOCK(p->p_pptr);
1115 
1116 				pp = proc_realparent(p);
1117 				proc_reparent(p, pp);
1118 				if (pp == initproc)
1119 					p->p_sigparent = SIGCHLD;
1120 				CTR3(KTR_PTRACE,
1121 			    "PT_DETACH: pid %d reparented to pid %d, sig %d",
1122 				    p->p_pid, pp->p_pid, data);
1123 			} else
1124 				CTR2(KTR_PTRACE, "PT_DETACH: pid %d, sig %d",
1125 				    p->p_pid, data);
1126 			p->p_oppid = 0;
1127 			p->p_ptevents = 0;
1128 			FOREACH_THREAD_IN_PROC(p, td3) {
1129 				if ((td3->td_dbgflags & TDB_FSTP) != 0) {
1130 					sigqueue_delete(&td3->td_sigqueue,
1131 					    SIGSTOP);
1132 				}
1133 				td3->td_dbgflags &= ~(TDB_XSIG | TDB_FSTP);
1134 			}
1135 			if ((p->p_flag2 & P2_PTRACE_FSTP) != 0) {
1136 				sigqueue_delete(&p->p_sigqueue, SIGSTOP);
1137 				p->p_flag2 &= ~P2_PTRACE_FSTP;
1138 			}
1139 
1140 			/* should we send SIGCHLD? */
1141 			/* childproc_continued(p); */
1142 			break;
1143 		}
1144 
1145 	sendsig:
1146 		if (proctree_locked) {
1147 			sx_xunlock(&proctree_lock);
1148 			proctree_locked = 0;
1149 		}
1150 		p->p_xsig = data;
1151 		p->p_xthread = NULL;
1152 		if ((p->p_flag & (P_STOPPED_SIG | P_STOPPED_TRACE)) != 0) {
1153 			/* deliver or queue signal */
1154 			td2->td_dbgflags &= ~TDB_XSIG;
1155 			td2->td_xsig = data;
1156 
1157 			/*
1158 			 * P_WKILLED is insurance that a PT_KILL/SIGKILL always
1159 			 * works immediately, even if another thread is
1160 			 * unsuspended first and attempts to handle a different
1161 			 * signal or if the POSIX.1b style signal queue cannot
1162 			 * accommodate any new signals.
1163 			 */
1164 			if (data == SIGKILL)
1165 				p->p_flag |= P_WKILLED;
1166 
1167 			if (req == PT_DETACH) {
1168 				FOREACH_THREAD_IN_PROC(p, td3)
1169 					td3->td_dbgflags &= ~TDB_SUSPEND;
1170 			}
1171 			/*
1172 			 * unsuspend all threads, to not let a thread run,
1173 			 * you should use PT_SUSPEND to suspend it before
1174 			 * continuing process.
1175 			 */
1176 			PROC_SLOCK(p);
1177 			p->p_flag &= ~(P_STOPPED_TRACE|P_STOPPED_SIG|P_WAITED);
1178 			thread_unsuspend(p);
1179 			PROC_SUNLOCK(p);
1180 			if (req == PT_ATTACH)
1181 				kern_psignal(p, data);
1182 		} else {
1183 			if (data)
1184 				kern_psignal(p, data);
1185 		}
1186 		break;
1187 
1188 	case PT_WRITE_I:
1189 	case PT_WRITE_D:
1190 		td2->td_dbgflags |= TDB_USERWR;
1191 		PROC_UNLOCK(p);
1192 		error = 0;
1193 		if (proc_writemem(td, p, (off_t)(uintptr_t)addr, &data,
1194 		    sizeof(int)) != sizeof(int))
1195 			error = ENOMEM;
1196 		else
1197 			CTR3(KTR_PTRACE, "PT_WRITE: pid %d: %p <= %#x",
1198 			    p->p_pid, addr, data);
1199 		PROC_LOCK(p);
1200 		break;
1201 
1202 	case PT_READ_I:
1203 	case PT_READ_D:
1204 		PROC_UNLOCK(p);
1205 		error = tmp = 0;
1206 		if (proc_readmem(td, p, (off_t)(uintptr_t)addr, &tmp,
1207 		    sizeof(int)) != sizeof(int))
1208 			error = ENOMEM;
1209 		else
1210 			CTR3(KTR_PTRACE, "PT_READ: pid %d: %p >= %#x",
1211 			    p->p_pid, addr, tmp);
1212 		td->td_retval[0] = tmp;
1213 		PROC_LOCK(p);
1214 		break;
1215 
1216 	case PT_IO:
1217 #ifdef COMPAT_FREEBSD32
1218 		if (wrap32) {
1219 			piod32 = addr;
1220 			iov.iov_base = (void *)(uintptr_t)piod32->piod_addr;
1221 			iov.iov_len = piod32->piod_len;
1222 			uio.uio_offset = (off_t)(uintptr_t)piod32->piod_offs;
1223 			uio.uio_resid = piod32->piod_len;
1224 		} else
1225 #endif
1226 		{
1227 			piod = addr;
1228 			iov.iov_base = piod->piod_addr;
1229 			iov.iov_len = piod->piod_len;
1230 			uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
1231 			uio.uio_resid = piod->piod_len;
1232 		}
1233 		uio.uio_iov = &iov;
1234 		uio.uio_iovcnt = 1;
1235 		uio.uio_segflg = UIO_USERSPACE;
1236 		uio.uio_td = td;
1237 #ifdef COMPAT_FREEBSD32
1238 		tmp = wrap32 ? piod32->piod_op : piod->piod_op;
1239 #else
1240 		tmp = piod->piod_op;
1241 #endif
1242 		switch (tmp) {
1243 		case PIOD_READ_D:
1244 		case PIOD_READ_I:
1245 			CTR3(KTR_PTRACE, "PT_IO: pid %d: READ (%p, %#x)",
1246 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1247 			uio.uio_rw = UIO_READ;
1248 			break;
1249 		case PIOD_WRITE_D:
1250 		case PIOD_WRITE_I:
1251 			CTR3(KTR_PTRACE, "PT_IO: pid %d: WRITE (%p, %#x)",
1252 			    p->p_pid, (uintptr_t)uio.uio_offset, uio.uio_resid);
1253 			td2->td_dbgflags |= TDB_USERWR;
1254 			uio.uio_rw = UIO_WRITE;
1255 			break;
1256 		default:
1257 			error = EINVAL;
1258 			goto out;
1259 		}
1260 		PROC_UNLOCK(p);
1261 		error = proc_rwmem(p, &uio);
1262 #ifdef COMPAT_FREEBSD32
1263 		if (wrap32)
1264 			piod32->piod_len -= uio.uio_resid;
1265 		else
1266 #endif
1267 			piod->piod_len -= uio.uio_resid;
1268 		PROC_LOCK(p);
1269 		break;
1270 
1271 	case PT_KILL:
1272 		CTR1(KTR_PTRACE, "PT_KILL: pid %d", p->p_pid);
1273 		data = SIGKILL;
1274 		goto sendsig;	/* in PT_CONTINUE above */
1275 
1276 	case PT_SETREGS:
1277 		CTR2(KTR_PTRACE, "PT_SETREGS: tid %d (pid %d)", td2->td_tid,
1278 		    p->p_pid);
1279 		td2->td_dbgflags |= TDB_USERWR;
1280 		error = PROC_WRITE(regs, td2, addr);
1281 		break;
1282 
1283 	case PT_GETREGS:
1284 		CTR2(KTR_PTRACE, "PT_GETREGS: tid %d (pid %d)", td2->td_tid,
1285 		    p->p_pid);
1286 		error = PROC_READ(regs, td2, addr);
1287 		break;
1288 
1289 	case PT_SETFPREGS:
1290 		CTR2(KTR_PTRACE, "PT_SETFPREGS: tid %d (pid %d)", td2->td_tid,
1291 		    p->p_pid);
1292 		td2->td_dbgflags |= TDB_USERWR;
1293 		error = PROC_WRITE(fpregs, td2, addr);
1294 		break;
1295 
1296 	case PT_GETFPREGS:
1297 		CTR2(KTR_PTRACE, "PT_GETFPREGS: tid %d (pid %d)", td2->td_tid,
1298 		    p->p_pid);
1299 		error = PROC_READ(fpregs, td2, addr);
1300 		break;
1301 
1302 	case PT_SETDBREGS:
1303 		CTR2(KTR_PTRACE, "PT_SETDBREGS: tid %d (pid %d)", td2->td_tid,
1304 		    p->p_pid);
1305 		td2->td_dbgflags |= TDB_USERWR;
1306 		error = PROC_WRITE(dbregs, td2, addr);
1307 		break;
1308 
1309 	case PT_GETDBREGS:
1310 		CTR2(KTR_PTRACE, "PT_GETDBREGS: tid %d (pid %d)", td2->td_tid,
1311 		    p->p_pid);
1312 		error = PROC_READ(dbregs, td2, addr);
1313 		break;
1314 
1315 	case PT_LWPINFO:
1316 		if (data <= 0 ||
1317 #ifdef COMPAT_FREEBSD32
1318 		    (!wrap32 && data > sizeof(*pl)) ||
1319 		    (wrap32 && data > sizeof(*pl32))) {
1320 #else
1321 		    data > sizeof(*pl)) {
1322 #endif
1323 			error = EINVAL;
1324 			break;
1325 		}
1326 #ifdef COMPAT_FREEBSD32
1327 		if (wrap32) {
1328 			pl = &plr;
1329 			pl32 = addr;
1330 		} else
1331 #endif
1332 		pl = addr;
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 ((pl->pl_flags & PL_FLAG_SI) == 0)
1354 			bzero(&pl->pl_siginfo, sizeof(pl->pl_siginfo));
1355 		if (td2->td_dbgflags & TDB_SCE)
1356 			pl->pl_flags |= PL_FLAG_SCE;
1357 		else if (td2->td_dbgflags & TDB_SCX)
1358 			pl->pl_flags |= PL_FLAG_SCX;
1359 		if (td2->td_dbgflags & TDB_EXEC)
1360 			pl->pl_flags |= PL_FLAG_EXEC;
1361 		if (td2->td_dbgflags & TDB_FORK) {
1362 			pl->pl_flags |= PL_FLAG_FORKED;
1363 			pl->pl_child_pid = td2->td_dbg_forked;
1364 			if (td2->td_dbgflags & TDB_VFORK)
1365 				pl->pl_flags |= PL_FLAG_VFORKED;
1366 		} else if ((td2->td_dbgflags & (TDB_SCX | TDB_VFORK)) ==
1367 		    TDB_VFORK)
1368 			pl->pl_flags |= PL_FLAG_VFORK_DONE;
1369 		if (td2->td_dbgflags & TDB_CHILD)
1370 			pl->pl_flags |= PL_FLAG_CHILD;
1371 		if (td2->td_dbgflags & TDB_BORN)
1372 			pl->pl_flags |= PL_FLAG_BORN;
1373 		if (td2->td_dbgflags & TDB_EXIT)
1374 			pl->pl_flags |= PL_FLAG_EXITED;
1375 		pl->pl_sigmask = td2->td_sigmask;
1376 		pl->pl_siglist = td2->td_siglist;
1377 		strcpy(pl->pl_tdname, td2->td_name);
1378 		if ((td2->td_dbgflags & (TDB_SCE | TDB_SCX)) != 0) {
1379 			pl->pl_syscall_code = td2->td_sa.code;
1380 			pl->pl_syscall_narg = td2->td_sa.narg;
1381 		} else {
1382 			pl->pl_syscall_code = 0;
1383 			pl->pl_syscall_narg = 0;
1384 		}
1385 #ifdef COMPAT_FREEBSD32
1386 		if (wrap32)
1387 			ptrace_lwpinfo_to32(pl, pl32);
1388 #endif
1389 		CTR6(KTR_PTRACE,
1390     "PT_LWPINFO: tid %d (pid %d) event %d flags %#x child pid %d syscall %d",
1391 		    td2->td_tid, p->p_pid, pl->pl_event, pl->pl_flags,
1392 		    pl->pl_child_pid, pl->pl_syscall_code);
1393 		break;
1394 
1395 	case PT_GETNUMLWPS:
1396 		CTR2(KTR_PTRACE, "PT_GETNUMLWPS: pid %d: %d threads", p->p_pid,
1397 		    p->p_numthreads);
1398 		td->td_retval[0] = p->p_numthreads;
1399 		break;
1400 
1401 	case PT_GETLWPLIST:
1402 		CTR3(KTR_PTRACE, "PT_GETLWPLIST: pid %d: data %d, actual %d",
1403 		    p->p_pid, data, p->p_numthreads);
1404 		if (data <= 0) {
1405 			error = EINVAL;
1406 			break;
1407 		}
1408 		num = imin(p->p_numthreads, data);
1409 		PROC_UNLOCK(p);
1410 		buf = malloc(num * sizeof(lwpid_t), M_TEMP, M_WAITOK);
1411 		tmp = 0;
1412 		PROC_LOCK(p);
1413 		FOREACH_THREAD_IN_PROC(p, td2) {
1414 			if (tmp >= num)
1415 				break;
1416 			buf[tmp++] = td2->td_tid;
1417 		}
1418 		PROC_UNLOCK(p);
1419 		error = copyout(buf, addr, tmp * sizeof(lwpid_t));
1420 		free(buf, M_TEMP);
1421 		if (!error)
1422 			td->td_retval[0] = tmp;
1423 		PROC_LOCK(p);
1424 		break;
1425 
1426 	case PT_VM_TIMESTAMP:
1427 		CTR2(KTR_PTRACE, "PT_VM_TIMESTAMP: pid %d: timestamp %d",
1428 		    p->p_pid, p->p_vmspace->vm_map.timestamp);
1429 		td->td_retval[0] = p->p_vmspace->vm_map.timestamp;
1430 		break;
1431 
1432 	case PT_VM_ENTRY:
1433 		PROC_UNLOCK(p);
1434 #ifdef COMPAT_FREEBSD32
1435 		if (wrap32)
1436 			error = ptrace_vm_entry32(td, p, addr);
1437 		else
1438 #endif
1439 		error = ptrace_vm_entry(td, p, addr);
1440 		PROC_LOCK(p);
1441 		break;
1442 
1443 	default:
1444 #ifdef __HAVE_PTRACE_MACHDEP
1445 		if (req >= PT_FIRSTMACH) {
1446 			PROC_UNLOCK(p);
1447 			error = cpu_ptrace(td2, req, addr, data);
1448 			PROC_LOCK(p);
1449 		} else
1450 #endif
1451 			/* Unknown request. */
1452 			error = EINVAL;
1453 		break;
1454 	}
1455 
1456 out:
1457 	/* Drop our hold on this process now that the request has completed. */
1458 	_PRELE(p);
1459 fail:
1460 	PROC_UNLOCK(p);
1461 	if (proctree_locked)
1462 		sx_xunlock(&proctree_lock);
1463 	return (error);
1464 }
1465 #undef PROC_READ
1466 #undef PROC_WRITE
1467 
1468 /*
1469  * Stop a process because of a debugging event;
1470  * stay stopped until p->p_step is cleared
1471  * (cleared by PIOCCONT in procfs).
1472  */
1473 void
1474 stopevent(struct proc *p, unsigned int event, unsigned int val)
1475 {
1476 
1477 	PROC_LOCK_ASSERT(p, MA_OWNED);
1478 	p->p_step = 1;
1479 	CTR3(KTR_PTRACE, "stopevent: pid %d event %u val %u", p->p_pid, event,
1480 	    val);
1481 	do {
1482 		if (event != S_EXIT)
1483 			p->p_xsig = val;
1484 		p->p_xthread = NULL;
1485 		p->p_stype = event;	/* Which event caused the stop? */
1486 		wakeup(&p->p_stype);	/* Wake up any PIOCWAIT'ing procs */
1487 		msleep(&p->p_step, &p->p_mtx, PWAIT, "stopevent", 0);
1488 	} while (p->p_step);
1489 }
1490