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 * $FreeBSD: src/sys/kern/sys_process.c,v 1.51.2.6 2003/01/08 03:06:45 kan Exp $
32 */
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/sysmsg.h>
37 #include <sys/uio.h>
38 #include <sys/proc.h>
39 #include <sys/caps.h>
40 #include <sys/vnode.h>
41 #include <sys/ptrace.h>
42 #include <sys/reg.h>
43 #include <sys/lock.h>
44
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47 #include <vm/vm_map.h>
48 #include <vm/vm_page.h>
49
50 #include <vfs/procfs/procfs.h>
51
52 #include <sys/thread2.h>
53 #include <sys/spinlock2.h>
54
55 /* use the equivalent procfs code */
56 #if 0
57 static int
58 pread (struct proc *procp, unsigned int addr, unsigned int *retval)
59 {
60 int rv;
61 vm_map_t map, tmap;
62 vm_object_t object;
63 vm_map_backing_t ba;
64 vm_offset_t kva = 0;
65 int page_offset; /* offset into page */
66 vm_offset_t pageno; /* page number */
67 vm_map_entry_t out_entry;
68 vm_prot_t out_prot;
69 int wflags;
70 vm_pindex_t pindex;
71 vm_pindex_t pcount;
72
73 /* Map page into kernel space */
74
75 map = &procp->p_vmspace->vm_map;
76
77 page_offset = addr - trunc_page(addr);
78 pageno = trunc_page(addr);
79
80 tmap = map;
81 rv = vm_map_lookup(&tmap, pageno, VM_PROT_READ, &out_entry,
82 &ba, &pindex, &pcount, &out_prot, &wflags);
83 if (ba)
84 object = ba->object;
85 else
86 object = NULL;
87
88
89 if (rv != KERN_SUCCESS)
90 return EINVAL;
91
92 vm_map_lookup_done (tmap, out_entry, 0);
93
94 /* Find space in kernel_map for the page we're interested in */
95 rv = vm_map_find (kernel_map, object, NULL,
96 IDX_TO_OFF(pindex), &kva, PAGE_SIZE,
97 PAGE_SIZE, FALSE,
98 VM_MAPTYPE_NORMAL, VM_SUBSYS_PROC,
99 VM_PROT_ALL, VM_PROT_ALL, 0);
100
101 if (!rv) {
102 vm_object_reference XXX (object);
103
104 /* wire the pages */
105 rv = vm_map_kernel_wiring(kernel_map, kva, kva + PAGE_SIZE, 0);
106 if (!rv) {
107 *retval = 0;
108 bcopy ((caddr_t)kva + page_offset,
109 retval, sizeof *retval);
110 }
111 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE);
112 }
113
114 return rv;
115 }
116
117 static int
118 pwrite (struct proc *procp, unsigned int addr, unsigned int datum)
119 {
120 int rv;
121 vm_map_t map, tmap;
122 vm_object_t object;
123 vm_map_backing_t ba;
124 vm_offset_t kva = 0;
125 int page_offset; /* offset into page */
126 vm_offset_t pageno; /* page number */
127 vm_map_entry_t out_entry;
128 vm_prot_t out_prot;
129 int wflags;
130 vm_pindex_t pindex;
131 vm_pindex_t pcount;
132 boolean_t fix_prot = 0;
133
134 /* Map page into kernel space */
135
136 map = &procp->p_vmspace->vm_map;
137
138 page_offset = addr - trunc_page(addr);
139 pageno = trunc_page(addr);
140
141 /*
142 * Check the permissions for the area we're interested in.
143 */
144
145 if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE,
146 VM_PROT_WRITE, FALSE) == FALSE) {
147 /*
148 * If the page was not writable, we make it so.
149 * XXX It is possible a page may *not* be read/executable,
150 * if a process changes that!
151 */
152 fix_prot = 1;
153 /* The page isn't writable, so let's try making it so... */
154 if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE,
155 VM_PROT_ALL, 0)) != KERN_SUCCESS)
156 return EFAULT; /* I guess... */
157 }
158
159 /*
160 * Now we need to get the page. out_entry, out_prot, wflags, and
161 * single_use aren't used. One would think the vm code would be
162 * a *bit* nicer... We use tmap because vm_map_lookup() can
163 * change the map argument.
164 */
165
166 tmap = map;
167 rv = vm_map_lookup(&tmap, pageno, VM_PROT_WRITE, &out_entry,
168 &ba, &pindex, &pcount, &out_prot, &wflags);
169 if (ba)
170 object = ba->object;
171 else
172 object = NULL;
173
174 if (rv != KERN_SUCCESS)
175 return EINVAL;
176
177 /*
178 * Okay, we've got the page. Let's release tmap.
179 */
180 vm_map_lookup_done (tmap, out_entry, 0);
181
182 /*
183 * Fault the page in...
184 */
185 rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE);
186 if (rv != KERN_SUCCESS)
187 return EFAULT;
188
189 /* Find space in kernel_map for the page we're interested in */
190 rv = vm_map_find (kernel_map, object, NULL,
191 IDX_TO_OFF(pindex), &kva, PAGE_SIZE,
192 PAGE_SIZE, FALSE,
193 VM_MAPTYPE_NORMAL, VM_SUBSYS_PROC,
194 VM_PROT_ALL, VM_PROT_ALL, 0);
195 if (!rv) {
196 vm_object_reference XXX (object);
197
198 /* wire the pages */
199 rv = vm_map_kernel_wiring(kernel_map, kva, kva + PAGE_SIZE, 0);
200 if (!rv) {
201 bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum);
202 }
203 vm_map_remove (kernel_map, kva, kva + PAGE_SIZE);
204 }
205
206 if (fix_prot)
207 vm_map_protect (map, pageno, pageno + PAGE_SIZE,
208 VM_PROT_READ|VM_PROT_EXECUTE, 0);
209 return rv;
210 }
211 #endif
212
213 /*
214 * Process debugging system call.
215 *
216 * MPALMOSTSAFE
217 */
218 int
sys_ptrace(struct sysmsg * sysmsg,const struct ptrace_args * uap)219 sys_ptrace(struct sysmsg *sysmsg, const struct ptrace_args *uap)
220 {
221 struct proc *p = curproc;
222
223 /*
224 * XXX this obfuscation is to reduce stack usage, but the register
225 * structs may be too large to put on the stack anyway.
226 */
227 union {
228 struct ptrace_io_desc piod;
229 struct dbreg dbreg;
230 struct fpreg fpreg;
231 struct reg reg;
232 } r;
233 void *addr;
234 int error = 0;
235
236 addr = &r;
237 switch (uap->req) {
238 case PT_GETREGS:
239 case PT_GETFPREGS:
240 #ifdef PT_GETDBREGS
241 case PT_GETDBREGS:
242 #endif
243 break;
244 case PT_SETREGS:
245 error = copyin(uap->addr, &r.reg, sizeof r.reg);
246 break;
247 case PT_SETFPREGS:
248 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg);
249 break;
250 #ifdef PT_SETDBREGS
251 case PT_SETDBREGS:
252 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg);
253 break;
254 #endif
255 case PT_IO:
256 error = copyin(uap->addr, &r.piod, sizeof r.piod);
257 break;
258 default:
259 addr = uap->addr;
260 }
261 if (error)
262 return (error);
263
264 error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data,
265 &sysmsg->sysmsg_result);
266 if (error)
267 return (error);
268
269 switch (uap->req) {
270 case PT_IO:
271 (void)copyout(&r.piod, uap->addr, sizeof r.piod);
272 break;
273 case PT_GETREGS:
274 error = copyout(&r.reg, uap->addr, sizeof r.reg);
275 break;
276 case PT_GETFPREGS:
277 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg);
278 break;
279 #ifdef PT_GETDBREGS
280 case PT_GETDBREGS:
281 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg);
282 break;
283 #endif
284 }
285
286 return (error);
287 }
288
289 int
kern_ptrace(struct proc * curp,int req,pid_t pid,void * addr,int data,int * res)290 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr,
291 int data, int *res)
292 {
293 struct proc *p, *pp;
294 struct lwp *lp;
295 struct iovec iov;
296 struct uio uio;
297 struct ptrace_io_desc *piod;
298 int error = 0;
299 int write, tmp;
300 int t;
301
302 write = 0;
303 if (req == PT_TRACE_ME) {
304 p = curp;
305 PHOLD(p);
306 } else {
307 if ((p = pfind(pid)) == NULL)
308 return ESRCH;
309 }
310 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) {
311 PRELE(p);
312 return (ESRCH);
313 }
314 if (p->p_flags & P_SYSTEM) {
315 PRELE(p);
316 return EINVAL;
317 }
318
319 lwkt_gettoken(&p->p_token);
320 /* Can't trace a process that's currently exec'ing. */
321 if ((p->p_flags & P_INEXEC) != 0) {
322 lwkt_reltoken(&p->p_token);
323 PRELE(p);
324 return EAGAIN;
325 }
326
327 /*
328 * Permissions check
329 */
330 switch (req) {
331 case PT_TRACE_ME:
332 /* Always legal. */
333 break;
334
335 case PT_ATTACH:
336 /* Self */
337 if (p->p_pid == curp->p_pid) {
338 lwkt_reltoken(&p->p_token);
339 PRELE(p);
340 return EINVAL;
341 }
342
343 /* Already traced */
344 if (p->p_flags & P_TRACED) {
345 lwkt_reltoken(&p->p_token);
346 PRELE(p);
347 return EBUSY;
348 }
349
350 if (curp->p_flags & P_TRACED)
351 for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr)
352 if (pp == p) {
353 lwkt_reltoken(&p->p_token);
354 PRELE(p);
355 return (EINVAL);
356 }
357
358 /* not owned by you, has done setuid (unless you're root) */
359 if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) ||
360 (p->p_flags & P_SUGID)) {
361 error = caps_priv_check(curp->p_ucred,
362 SYSCAP_RESTRICTEDROOT);
363 if (error) {
364 lwkt_reltoken(&p->p_token);
365 PRELE(p);
366 return error;
367 }
368 }
369
370 /* can't trace init when securelevel > 0 */
371 if (securelevel > 0 && p->p_pid == 1) {
372 lwkt_reltoken(&p->p_token);
373 PRELE(p);
374 return EPERM;
375 }
376
377 /* OK */
378 break;
379
380 case PT_READ_I:
381 case PT_READ_D:
382 case PT_WRITE_I:
383 case PT_WRITE_D:
384 case PT_IO:
385 case PT_CONTINUE:
386 case PT_KILL:
387 case PT_STEP:
388 case PT_DETACH:
389 #ifdef PT_GETREGS
390 case PT_GETREGS:
391 #endif
392 #ifdef PT_SETREGS
393 case PT_SETREGS:
394 #endif
395 #ifdef PT_GETFPREGS
396 case PT_GETFPREGS:
397 #endif
398 #ifdef PT_SETFPREGS
399 case PT_SETFPREGS:
400 #endif
401 #ifdef PT_GETDBREGS
402 case PT_GETDBREGS:
403 #endif
404 #ifdef PT_SETDBREGS
405 case PT_SETDBREGS:
406 #endif
407 /* not being traced... */
408 if ((p->p_flags & P_TRACED) == 0) {
409 lwkt_reltoken(&p->p_token);
410 PRELE(p);
411 return EPERM;
412 }
413
414 /* not being traced by YOU */
415 if (p->p_pptr != curp) {
416 lwkt_reltoken(&p->p_token);
417 PRELE(p);
418 return EBUSY;
419 }
420
421 /* not currently stopped */
422 if (p->p_stat != SSTOP ||
423 (p->p_flags & P_WAITED) == 0) {
424 lwkt_reltoken(&p->p_token);
425 PRELE(p);
426 return EBUSY;
427 }
428
429 /* OK */
430 break;
431
432 default:
433 lwkt_reltoken(&p->p_token);
434 PRELE(p);
435 return EINVAL;
436 }
437
438 /* XXX lwp */
439 lp = FIRST_LWP_IN_PROC(p);
440 if (lp == NULL) {
441 lwkt_reltoken(&p->p_token);
442 PRELE(p);
443 return EINVAL;
444 }
445
446 #ifdef FIX_SSTEP
447 /*
448 * Single step fixup ala procfs
449 */
450 FIX_SSTEP(lp);
451 #endif
452
453 /*
454 * Actually do the requests
455 */
456
457 *res = 0;
458
459 switch (req) {
460 case PT_TRACE_ME:
461 /* set my trace flag and "owner" so it can read/write me */
462 p->p_flags |= P_TRACED;
463 p->p_oppid = p->p_pptr->p_pid;
464 lwkt_reltoken(&p->p_token);
465 PRELE(p);
466 return 0;
467
468 case PT_ATTACH:
469 /* security check done above */
470 p->p_flags |= P_TRACED;
471 p->p_oppid = p->p_pptr->p_pid;
472 proc_reparent(p, curp);
473 data = SIGSTOP;
474 goto sendsig; /* in PT_CONTINUE below */
475
476 case PT_STEP:
477 case PT_CONTINUE:
478 case PT_DETACH:
479 /* Zero means do not send any signal */
480 if (data < 0 || data >= _SIG_MAXSIG) {
481 lwkt_reltoken(&p->p_token);
482 PRELE(p);
483 return EINVAL;
484 }
485
486 LWPHOLD(lp);
487
488 if (req == PT_STEP) {
489 if ((error = ptrace_single_step (lp))) {
490 LWPRELE(lp);
491 lwkt_reltoken(&p->p_token);
492 PRELE(p);
493 return error;
494 }
495 }
496
497 if (addr != (void *)1) {
498 if ((error = ptrace_set_pc (lp, (u_long)addr))) {
499 LWPRELE(lp);
500 lwkt_reltoken(&p->p_token);
501 PRELE(p);
502 return error;
503 }
504 }
505 LWPRELE(lp);
506
507 if (req == PT_DETACH) {
508 /* reset process parent */
509 if (p->p_oppid != p->p_pptr->p_pid) {
510 struct proc *pp;
511
512 pp = pfind(p->p_oppid);
513 if (pp) {
514 proc_reparent(p, pp);
515 PRELE(pp);
516 }
517 }
518
519 p->p_flags &= ~(P_TRACED | P_WAITED);
520 p->p_oppid = 0;
521
522 /* should we send SIGCHLD? */
523 }
524
525 sendsig:
526 /*
527 * Deliver or queue signal. If the process is stopped
528 * force it to be SACTIVE again.
529 */
530 crit_enter();
531 if (p->p_stat == SSTOP) {
532 p->p_xstat = data;
533 proc_unstop(p, SSTOP);
534 } else if (data) {
535 ksignal(p, data);
536 }
537 crit_exit();
538 lwkt_reltoken(&p->p_token);
539 PRELE(p);
540 return 0;
541
542 case PT_WRITE_I:
543 case PT_WRITE_D:
544 write = 1;
545 /* fallthrough */
546 case PT_READ_I:
547 case PT_READ_D:
548 /*
549 * NOTE! uio_offset represents the offset in the target
550 * process. The iov is in the current process (the guy
551 * making the ptrace call) so uio_td must be the current
552 * process (though for a SYSSPACE transfer it doesn't
553 * really matter).
554 */
555 tmp = 0;
556 /* write = 0 set above */
557 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
558 iov.iov_len = sizeof(int);
559 uio.uio_iov = &iov;
560 uio.uio_iovcnt = 1;
561 uio.uio_offset = (off_t)(uintptr_t)addr;
562 uio.uio_resid = sizeof(int);
563 uio.uio_segflg = UIO_SYSSPACE;
564 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
565 uio.uio_td = curthread;
566 error = procfs_domem(curp, lp, NULL, &uio);
567 if (uio.uio_resid != 0) {
568 /*
569 * XXX procfs_domem() doesn't currently return ENOSPC,
570 * so I think write() can bogusly return 0.
571 * XXX what happens for short writes? We don't want
572 * to write partial data.
573 * XXX procfs_domem() returns EPERM for other invalid
574 * addresses. Convert this to EINVAL. Does this
575 * clobber returns of EPERM for other reasons?
576 */
577 if (error == 0 || error == ENOSPC || error == EPERM)
578 error = EINVAL; /* EOF */
579 }
580 if (!write)
581 *res = tmp;
582 lwkt_reltoken(&p->p_token);
583 PRELE(p);
584 return (error);
585
586 case PT_IO:
587 /*
588 * NOTE! uio_offset represents the offset in the target
589 * process. The iov is in the current process (the guy
590 * making the ptrace call) so uio_td must be the current
591 * process.
592 */
593 piod = addr;
594 iov.iov_base = piod->piod_addr;
595 iov.iov_len = piod->piod_len;
596 uio.uio_iov = &iov;
597 uio.uio_iovcnt = 1;
598 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
599 uio.uio_resid = piod->piod_len;
600 uio.uio_segflg = UIO_USERSPACE;
601 uio.uio_td = curthread;
602 switch (piod->piod_op) {
603 case PIOD_READ_D:
604 case PIOD_READ_I:
605 uio.uio_rw = UIO_READ;
606 break;
607 case PIOD_WRITE_D:
608 case PIOD_WRITE_I:
609 uio.uio_rw = UIO_WRITE;
610 break;
611 default:
612 lwkt_reltoken(&p->p_token);
613 PRELE(p);
614 return (EINVAL);
615 }
616 error = procfs_domem(curp, lp, NULL, &uio);
617 piod->piod_len -= uio.uio_resid;
618 lwkt_reltoken(&p->p_token);
619 PRELE(p);
620 return (error);
621
622 case PT_KILL:
623 data = SIGKILL;
624 goto sendsig; /* in PT_CONTINUE above */
625
626 #ifdef PT_SETREGS
627 case PT_SETREGS:
628 write = 1;
629 /* fallthrough */
630 #endif /* PT_SETREGS */
631 #ifdef PT_GETREGS
632 case PT_GETREGS:
633 /* write = 0 above */
634 #endif /* PT_SETREGS */
635 #if defined(PT_SETREGS) || defined(PT_GETREGS)
636 if (!procfs_validregs(lp)) {
637 lwkt_reltoken(&p->p_token);
638 PRELE(p);
639 return EINVAL;
640 } else {
641 iov.iov_base = addr;
642 iov.iov_len = sizeof(struct reg);
643 uio.uio_iov = &iov;
644 uio.uio_iovcnt = 1;
645 uio.uio_offset = 0;
646 uio.uio_resid = sizeof(struct reg);
647 uio.uio_segflg = UIO_SYSSPACE;
648 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
649 uio.uio_td = curthread;
650 t = procfs_doregs(curp, lp, NULL, &uio);
651 lwkt_reltoken(&p->p_token);
652 PRELE(p);
653 return t;
654 }
655 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */
656
657 #ifdef PT_SETFPREGS
658 case PT_SETFPREGS:
659 write = 1;
660 /* fallthrough */
661 #endif /* PT_SETFPREGS */
662 #ifdef PT_GETFPREGS
663 case PT_GETFPREGS:
664 /* write = 0 above */
665 #endif /* PT_SETFPREGS */
666 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
667 if (!procfs_validfpregs(lp)) {
668 lwkt_reltoken(&p->p_token);
669 PRELE(p);
670 return EINVAL;
671 } else {
672 iov.iov_base = addr;
673 iov.iov_len = sizeof(struct fpreg);
674 uio.uio_iov = &iov;
675 uio.uio_iovcnt = 1;
676 uio.uio_offset = 0;
677 uio.uio_resid = sizeof(struct fpreg);
678 uio.uio_segflg = UIO_SYSSPACE;
679 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
680 uio.uio_td = curthread;
681 t = procfs_dofpregs(curp, lp, NULL, &uio);
682 lwkt_reltoken(&p->p_token);
683 PRELE(p);
684 return t;
685 }
686 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */
687
688 #ifdef PT_SETDBREGS
689 case PT_SETDBREGS:
690 write = 1;
691 /* fallthrough */
692 #endif /* PT_SETDBREGS */
693 #ifdef PT_GETDBREGS
694 case PT_GETDBREGS:
695 /* write = 0 above */
696 #endif /* PT_SETDBREGS */
697 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS)
698 if (!procfs_validdbregs(lp)) {
699 lwkt_reltoken(&p->p_token);
700 PRELE(p);
701 return EINVAL;
702 } else {
703 iov.iov_base = addr;
704 iov.iov_len = sizeof(struct dbreg);
705 uio.uio_iov = &iov;
706 uio.uio_iovcnt = 1;
707 uio.uio_offset = 0;
708 uio.uio_resid = sizeof(struct dbreg);
709 uio.uio_segflg = UIO_SYSSPACE;
710 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
711 uio.uio_td = curthread;
712 t = procfs_dodbregs(curp, lp, NULL, &uio);
713 lwkt_reltoken(&p->p_token);
714 PRELE(p);
715 return t;
716 }
717 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */
718
719 default:
720 break;
721 }
722
723 lwkt_reltoken(&p->p_token);
724 PRELE(p);
725
726 return 0;
727 }
728
729 int
trace_req(struct proc * p)730 trace_req(struct proc *p)
731 {
732 return 1;
733 }
734
735 /*
736 * stopevent()
737 *
738 * Stop a process because of a procfs event. Stay stopped until p->p_step
739 * is cleared (cleared by PIOCCONT in procfs).
740 *
741 * MPSAFE
742 */
743 void
stopevent(struct proc * p,unsigned int event,unsigned int val)744 stopevent(struct proc *p, unsigned int event, unsigned int val)
745 {
746 /*
747 * Set event info. Recheck p_stops in case we are
748 * racing a close() on procfs.
749 */
750 spin_lock(&p->p_spin);
751 if ((p->p_stops & event) == 0) {
752 spin_unlock(&p->p_spin);
753 return;
754 }
755 p->p_xstat = val;
756 p->p_stype = event;
757 p->p_step = 1;
758 tsleep_interlock(&p->p_step, 0);
759 spin_unlock(&p->p_spin);
760
761 /*
762 * Wakeup any PIOCWAITing procs and wait for p_step to
763 * be cleared.
764 */
765 for (;;) {
766 wakeup(&p->p_stype);
767 tsleep(&p->p_step, PINTERLOCKED, "stopevent", 0);
768 spin_lock(&p->p_spin);
769 if (p->p_step == 0) {
770 spin_unlock(&p->p_spin);
771 break;
772 }
773 tsleep_interlock(&p->p_step, 0);
774 spin_unlock(&p->p_spin);
775 }
776 }
777
778