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usr.sbin/makefs/ffs: Remove m_buf::b_is_hammer2
[dragonfly.git] / sys / kern / sys_process.c
blobef51141d6d0afef2d9d0f5de15ed249288f203fd
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/priv.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
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
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 if ((error = priv_check_cred(curp->p_ucred, PRIV_ROOT, 0)) != 0) {
362 lwkt_reltoken(&p->p_token);
363 PRELE(p);
364 return error;
365 }
366 }
367
368 /* can't trace init when securelevel > 0 */
369 if (securelevel > 0 && p->p_pid == 1) {
370 lwkt_reltoken(&p->p_token);
371 PRELE(p);
372 return EPERM;
373 }
374
375 /* OK */
376 break;
377
378 case PT_READ_I:
379 case PT_READ_D:
380 case PT_WRITE_I:
381 case PT_WRITE_D:
382 case PT_IO:
383 case PT_CONTINUE:
384 case PT_KILL:
385 case PT_STEP:
386 case PT_DETACH:
387 #ifdef PT_GETREGS
388 case PT_GETREGS:
389 #endif
390 #ifdef PT_SETREGS
391 case PT_SETREGS:
392 #endif
393 #ifdef PT_GETFPREGS
394 case PT_GETFPREGS:
395 #endif
396 #ifdef PT_SETFPREGS
397 case PT_SETFPREGS:
398 #endif
399 #ifdef PT_GETDBREGS
400 case PT_GETDBREGS:
401 #endif
402 #ifdef PT_SETDBREGS
403 case PT_SETDBREGS:
404 #endif
405 /* not being traced... */
406 if ((p->p_flags & P_TRACED) == 0) {
407 lwkt_reltoken(&p->p_token);
408 PRELE(p);
409 return EPERM;
410 }
411
412 /* not being traced by YOU */
413 if (p->p_pptr != curp) {
414 lwkt_reltoken(&p->p_token);
415 PRELE(p);
416 return EBUSY;
417 }
418
419 /* not currently stopped */
420 if (p->p_stat != SSTOP ||
421 (p->p_flags & P_WAITED) == 0) {
422 lwkt_reltoken(&p->p_token);
423 PRELE(p);
424 return EBUSY;
425 }
426
427 /* OK */
428 break;
429
430 default:
431 lwkt_reltoken(&p->p_token);
432 PRELE(p);
433 return EINVAL;
434 }
435
436 /* XXX lwp */
437 lp = FIRST_LWP_IN_PROC(p);
438 if (lp == NULL) {
439 lwkt_reltoken(&p->p_token);
440 PRELE(p);
441 return EINVAL;
442 }
443
444 #ifdef FIX_SSTEP
445 /*
446 * Single step fixup ala procfs
447 */
448 FIX_SSTEP(lp);
449 #endif
450
451 /*
452 * Actually do the requests
453 */
454
455 *res = 0;
456
457 switch (req) {
458 case PT_TRACE_ME:
459 /* set my trace flag and "owner" so it can read/write me */
460 p->p_flags |= P_TRACED;
461 p->p_oppid = p->p_pptr->p_pid;
462 lwkt_reltoken(&p->p_token);
463 PRELE(p);
464 return 0;
465
466 case PT_ATTACH:
467 /* security check done above */
468 p->p_flags |= P_TRACED;
469 p->p_oppid = p->p_pptr->p_pid;
470 proc_reparent(p, curp);
471 data = SIGSTOP;
472 goto sendsig; /* in PT_CONTINUE below */
473
474 case PT_STEP:
475 case PT_CONTINUE:
476 case PT_DETACH:
477 /* Zero means do not send any signal */
478 if (data < 0 || data >= _SIG_MAXSIG) {
479 lwkt_reltoken(&p->p_token);
480 PRELE(p);
481 return EINVAL;
482 }
483
484 LWPHOLD(lp);
485
486 if (req == PT_STEP) {
487 if ((error = ptrace_single_step (lp))) {
488 LWPRELE(lp);
489 lwkt_reltoken(&p->p_token);
490 PRELE(p);
491 return error;
492 }
493 }
494
495 if (addr != (void *)1) {
496 if ((error = ptrace_set_pc (lp, (u_long)addr))) {
497 LWPRELE(lp);
498 lwkt_reltoken(&p->p_token);
499 PRELE(p);
500 return error;
501 }
502 }
503 LWPRELE(lp);
504
505 if (req == PT_DETACH) {
506 /* reset process parent */
507 if (p->p_oppid != p->p_pptr->p_pid) {
508 struct proc *pp;
509
510 pp = pfind(p->p_oppid);
511 if (pp) {
512 proc_reparent(p, pp);
513 PRELE(pp);
514 }
515 }
516
517 p->p_flags &= ~(P_TRACED | P_WAITED);
518 p->p_oppid = 0;
519
520 /* should we send SIGCHLD? */
521 }
522
523 sendsig:
524 /*
525 * Deliver or queue signal. If the process is stopped
526 * force it to be SACTIVE again.
527 */
528 crit_enter();
529 if (p->p_stat == SSTOP) {
530 p->p_xstat = data;
531 proc_unstop(p, SSTOP);
532 } else if (data) {
533 ksignal(p, data);
534 }
535 crit_exit();
536 lwkt_reltoken(&p->p_token);
537 PRELE(p);
538 return 0;
539
540 case PT_WRITE_I:
541 case PT_WRITE_D:
542 write = 1;
543 /* fallthrough */
544 case PT_READ_I:
545 case PT_READ_D:
546 /*
547 * NOTE! uio_offset represents the offset in the target
548 * process. The iov is in the current process (the guy
549 * making the ptrace call) so uio_td must be the current
550 * process (though for a SYSSPACE transfer it doesn't
551 * really matter).
552 */
553 tmp = 0;
554 /* write = 0 set above */
555 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp;
556 iov.iov_len = sizeof(int);
557 uio.uio_iov = &iov;
558 uio.uio_iovcnt = 1;
559 uio.uio_offset = (off_t)(uintptr_t)addr;
560 uio.uio_resid = sizeof(int);
561 uio.uio_segflg = UIO_SYSSPACE;
562 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
563 uio.uio_td = curthread;
564 error = procfs_domem(curp, lp, NULL, &uio);
565 if (uio.uio_resid != 0) {
566 /*
567 * XXX procfs_domem() doesn't currently return ENOSPC,
568 * so I think write() can bogusly return 0.
569 * XXX what happens for short writes? We don't want
570 * to write partial data.
571 * XXX procfs_domem() returns EPERM for other invalid
572 * addresses. Convert this to EINVAL. Does this
573 * clobber returns of EPERM for other reasons?
574 */
575 if (error == 0 || error == ENOSPC || error == EPERM)
576 error = EINVAL; /* EOF */
577 }
578 if (!write)
579 *res = tmp;
580 lwkt_reltoken(&p->p_token);
581 PRELE(p);
582 return (error);
583
584 case PT_IO:
585 /*
586 * NOTE! uio_offset represents the offset in the target
587 * process. The iov is in the current process (the guy
588 * making the ptrace call) so uio_td must be the current
589 * process.
590 */
591 piod = addr;
592 iov.iov_base = piod->piod_addr;
593 iov.iov_len = piod->piod_len;
594 uio.uio_iov = &iov;
595 uio.uio_iovcnt = 1;
596 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs;
597 uio.uio_resid = piod->piod_len;
598 uio.uio_segflg = UIO_USERSPACE;
599 uio.uio_td = curthread;
600 switch (piod->piod_op) {
601 case PIOD_READ_D:
602 case PIOD_READ_I:
603 uio.uio_rw = UIO_READ;
604 break;
605 case PIOD_WRITE_D:
606 case PIOD_WRITE_I:
607 uio.uio_rw = UIO_WRITE;
608 break;
609 default:
610 lwkt_reltoken(&p->p_token);
611 PRELE(p);
612 return (EINVAL);
613 }
614 error = procfs_domem(curp, lp, NULL, &uio);
615 piod->piod_len -= uio.uio_resid;
616 lwkt_reltoken(&p->p_token);
617 PRELE(p);
618 return (error);
619
620 case PT_KILL:
621 data = SIGKILL;
622 goto sendsig; /* in PT_CONTINUE above */
623
624 #ifdef PT_SETREGS
625 case PT_SETREGS:
626 write = 1;
627 /* fallthrough */
628 #endif /* PT_SETREGS */
629 #ifdef PT_GETREGS
630 case PT_GETREGS:
631 /* write = 0 above */
632 #endif /* PT_SETREGS */
633 #if defined(PT_SETREGS) || defined(PT_GETREGS)
634 if (!procfs_validregs(lp)) {
635 lwkt_reltoken(&p->p_token);
636 PRELE(p);
637 return EINVAL;
638 } else {
639 iov.iov_base = addr;
640 iov.iov_len = sizeof(struct reg);
641 uio.uio_iov = &iov;
642 uio.uio_iovcnt = 1;
643 uio.uio_offset = 0;
644 uio.uio_resid = sizeof(struct reg);
645 uio.uio_segflg = UIO_SYSSPACE;
646 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
647 uio.uio_td = curthread;
648 t = procfs_doregs(curp, lp, NULL, &uio);
649 lwkt_reltoken(&p->p_token);
650 PRELE(p);
651 return t;
652 }
653 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */
654
655 #ifdef PT_SETFPREGS
656 case PT_SETFPREGS:
657 write = 1;
658 /* fallthrough */
659 #endif /* PT_SETFPREGS */
660 #ifdef PT_GETFPREGS
661 case PT_GETFPREGS:
662 /* write = 0 above */
663 #endif /* PT_SETFPREGS */
664 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS)
665 if (!procfs_validfpregs(lp)) {
666 lwkt_reltoken(&p->p_token);
667 PRELE(p);
668 return EINVAL;
669 } else {
670 iov.iov_base = addr;
671 iov.iov_len = sizeof(struct fpreg);
672 uio.uio_iov = &iov;
673 uio.uio_iovcnt = 1;
674 uio.uio_offset = 0;
675 uio.uio_resid = sizeof(struct fpreg);
676 uio.uio_segflg = UIO_SYSSPACE;
677 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
678 uio.uio_td = curthread;
679 t = procfs_dofpregs(curp, lp, NULL, &uio);
680 lwkt_reltoken(&p->p_token);
681 PRELE(p);
682 return t;
683 }
684 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */
685
686 #ifdef PT_SETDBREGS
687 case PT_SETDBREGS:
688 write = 1;
689 /* fallthrough */
690 #endif /* PT_SETDBREGS */
691 #ifdef PT_GETDBREGS
692 case PT_GETDBREGS:
693 /* write = 0 above */
694 #endif /* PT_SETDBREGS */
695 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS)
696 if (!procfs_validdbregs(lp)) {
697 lwkt_reltoken(&p->p_token);
698 PRELE(p);
699 return EINVAL;
700 } else {
701 iov.iov_base = addr;
702 iov.iov_len = sizeof(struct dbreg);
703 uio.uio_iov = &iov;
704 uio.uio_iovcnt = 1;
705 uio.uio_offset = 0;
706 uio.uio_resid = sizeof(struct dbreg);
707 uio.uio_segflg = UIO_SYSSPACE;
708 uio.uio_rw = write ? UIO_WRITE : UIO_READ;
709 uio.uio_td = curthread;
710 t = procfs_dodbregs(curp, lp, NULL, &uio);
711 lwkt_reltoken(&p->p_token);
712 PRELE(p);
713 return t;
714 }
715 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */
716
717 default:
718 break;
719 }
720
721 lwkt_reltoken(&p->p_token);
722 PRELE(p);
723
724 return 0;
725 }
726
727 int
728 trace_req(struct proc *p)
729 {
730 return 1;
731 }
732
733 /*
734 * stopevent()
735 *
736 * Stop a process because of a procfs event. Stay stopped until p->p_step
737 * is cleared (cleared by PIOCCONT in procfs).
738 *
739 * MPSAFE
740 */
741 void
742 stopevent(struct proc *p, unsigned int event, unsigned int val)
743 {
744 /*
745 * Set event info. Recheck p_stops in case we are
746 * racing a close() on procfs.
747 */
748 spin_lock(&p->p_spin);
749 if ((p->p_stops & event) == 0) {
750 spin_unlock(&p->p_spin);
751 return;
752 }
753 p->p_xstat = val;
754 p->p_stype = event;
755 p->p_step = 1;
756 tsleep_interlock(&p->p_step, 0);
757 spin_unlock(&p->p_spin);
758
759 /*
760 * Wakeup any PIOCWAITing procs and wait for p_step to
761 * be cleared.
762 */
763 for (;;) {
764 wakeup(&p->p_stype);
765 tsleep(&p->p_step, PINTERLOCKED, "stopevent", 0);
766 spin_lock(&p->p_spin);
767 if (p->p_step == 0) {
768 spin_unlock(&p->p_spin);
769 break;
770 }
771 tsleep_interlock(&p->p_step, 0);
772 spin_unlock(&p->p_spin);
773 }
774 }
775
DragonFly BSD