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 * $DragonFly: src/sys/kern/sys_process.c,v 1.30 2007/02/19 01:14:23 corecode Exp $ 33 */ 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/sysproto.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 <sys/user.h> 51 #include <vfs/procfs/procfs.h> 52 53 #include <sys/thread2.h> 54 #include <sys/spinlock2.h> 55 56 /* use the equivalent procfs code */ 57 #if 0 58 static int 59 pread (struct proc *procp, unsigned int addr, unsigned int *retval) { 60 int rv; 61 vm_map_t map, tmap; 62 vm_object_t object; 63 vm_offset_t kva = 0; 64 int page_offset; /* offset into page */ 65 vm_offset_t pageno; /* page number */ 66 vm_map_entry_t out_entry; 67 vm_prot_t out_prot; 68 int wflags; 69 vm_pindex_t pindex; 70 71 /* Map page into kernel space */ 72 73 map = &procp->p_vmspace->vm_map; 74 75 page_offset = addr - trunc_page(addr); 76 pageno = trunc_page(addr); 77 78 tmap = map; 79 rv = vm_map_lookup(&tmap, pageno, VM_PROT_READ, &out_entry, 80 &object, &pindex, &out_prot, &wflags); 81 82 if (rv != KERN_SUCCESS) 83 return EINVAL; 84 85 vm_map_lookup_done (tmap, out_entry, 0); 86 87 /* Find space in kernel_map for the page we're interested in */ 88 rv = vm_map_find (&kernel_map, object, NULL, 89 IDX_TO_OFF(pindex), &kva, PAGE_SIZE, 90 PAGE_SIZE, FALSE, 91 VM_MAPTYPE_NORMAL, VM_SUBSYS_PROC, 92 VM_PROT_ALL, VM_PROT_ALL, 0); 93 94 if (!rv) { 95 vm_object_reference XXX (object); 96 97 rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0); 98 if (!rv) { 99 *retval = 0; 100 bcopy ((caddr_t)kva + page_offset, 101 retval, sizeof *retval); 102 } 103 vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE); 104 } 105 106 return rv; 107 } 108 109 static int 110 pwrite (struct proc *procp, unsigned int addr, unsigned int datum) { 111 int rv; 112 vm_map_t map, tmap; 113 vm_object_t object; 114 vm_offset_t kva = 0; 115 int page_offset; /* offset into page */ 116 vm_offset_t pageno; /* page number */ 117 vm_map_entry_t out_entry; 118 vm_prot_t out_prot; 119 int wflags; 120 vm_pindex_t pindex; 121 boolean_t fix_prot = 0; 122 123 /* Map page into kernel space */ 124 125 map = &procp->p_vmspace->vm_map; 126 127 page_offset = addr - trunc_page(addr); 128 pageno = trunc_page(addr); 129 130 /* 131 * Check the permissions for the area we're interested in. 132 */ 133 134 if (vm_map_check_protection (map, pageno, pageno + PAGE_SIZE, 135 VM_PROT_WRITE, FALSE) == FALSE) { 136 /* 137 * If the page was not writable, we make it so. 138 * XXX It is possible a page may *not* be read/executable, 139 * if a process changes that! 140 */ 141 fix_prot = 1; 142 /* The page isn't writable, so let's try making it so... */ 143 if ((rv = vm_map_protect (map, pageno, pageno + PAGE_SIZE, 144 VM_PROT_ALL, 0)) != KERN_SUCCESS) 145 return EFAULT; /* I guess... */ 146 } 147 148 /* 149 * Now we need to get the page. out_entry, out_prot, wflags, and 150 * single_use aren't used. One would think the vm code would be 151 * a *bit* nicer... We use tmap because vm_map_lookup() can 152 * change the map argument. 153 */ 154 155 tmap = map; 156 rv = vm_map_lookup(&tmap, pageno, VM_PROT_WRITE, &out_entry, 157 &object, &pindex, &out_prot, &wflags); 158 if (rv != KERN_SUCCESS) 159 return EINVAL; 160 161 /* 162 * Okay, we've got the page. Let's release tmap. 163 */ 164 vm_map_lookup_done (tmap, out_entry, 0); 165 166 /* 167 * Fault the page in... 168 */ 169 rv = vm_fault(map, pageno, VM_PROT_WRITE|VM_PROT_READ, FALSE); 170 if (rv != KERN_SUCCESS) 171 return EFAULT; 172 173 /* Find space in kernel_map for the page we're interested in */ 174 rv = vm_map_find (&kernel_map, object, NULL, 175 IDX_TO_OFF(pindex), &kva, PAGE_SIZE, 176 PAGE_SIZE, FALSE, 177 VM_MAPTYPE_NORMAL, VM_SUBSYS_PROC, 178 VM_PROT_ALL, VM_PROT_ALL, 0); 179 if (!rv) { 180 vm_object_reference XXX (object); 181 182 rv = vm_map_wire (&kernel_map, kva, kva + PAGE_SIZE, 0); 183 if (!rv) { 184 bcopy (&datum, (caddr_t)kva + page_offset, sizeof datum); 185 } 186 vm_map_remove (&kernel_map, kva, kva + PAGE_SIZE); 187 } 188 189 if (fix_prot) 190 vm_map_protect (map, pageno, pageno + PAGE_SIZE, 191 VM_PROT_READ|VM_PROT_EXECUTE, 0); 192 return rv; 193 } 194 #endif 195 196 /* 197 * Process debugging system call. 198 * 199 * MPALMOSTSAFE 200 */ 201 int 202 sys_ptrace(struct ptrace_args *uap) 203 { 204 struct proc *p = curproc; 205 206 /* 207 * XXX this obfuscation is to reduce stack usage, but the register 208 * structs may be too large to put on the stack anyway. 209 */ 210 union { 211 struct ptrace_io_desc piod; 212 struct dbreg dbreg; 213 struct fpreg fpreg; 214 struct reg reg; 215 } r; 216 void *addr; 217 int error = 0; 218 219 addr = &r; 220 switch (uap->req) { 221 case PT_GETREGS: 222 case PT_GETFPREGS: 223 #ifdef PT_GETDBREGS 224 case PT_GETDBREGS: 225 #endif 226 break; 227 case PT_SETREGS: 228 error = copyin(uap->addr, &r.reg, sizeof r.reg); 229 break; 230 case PT_SETFPREGS: 231 error = copyin(uap->addr, &r.fpreg, sizeof r.fpreg); 232 break; 233 #ifdef PT_SETDBREGS 234 case PT_SETDBREGS: 235 error = copyin(uap->addr, &r.dbreg, sizeof r.dbreg); 236 break; 237 #endif 238 case PT_IO: 239 error = copyin(uap->addr, &r.piod, sizeof r.piod); 240 break; 241 default: 242 addr = uap->addr; 243 } 244 if (error) 245 return (error); 246 247 error = kern_ptrace(p, uap->req, uap->pid, addr, uap->data, 248 &uap->sysmsg_result); 249 if (error) 250 return (error); 251 252 switch (uap->req) { 253 case PT_IO: 254 (void)copyout(&r.piod, uap->addr, sizeof r.piod); 255 break; 256 case PT_GETREGS: 257 error = copyout(&r.reg, uap->addr, sizeof r.reg); 258 break; 259 case PT_GETFPREGS: 260 error = copyout(&r.fpreg, uap->addr, sizeof r.fpreg); 261 break; 262 #ifdef PT_GETDBREGS 263 case PT_GETDBREGS: 264 error = copyout(&r.dbreg, uap->addr, sizeof r.dbreg); 265 break; 266 #endif 267 } 268 269 return (error); 270 } 271 272 int 273 kern_ptrace(struct proc *curp, int req, pid_t pid, void *addr, 274 int data, int *res) 275 { 276 struct proc *p, *pp; 277 struct lwp *lp; 278 struct iovec iov; 279 struct uio uio; 280 struct ptrace_io_desc *piod; 281 int error = 0; 282 int write, tmp; 283 int t; 284 285 write = 0; 286 if (req == PT_TRACE_ME) { 287 p = curp; 288 PHOLD(p); 289 } else { 290 if ((p = pfind(pid)) == NULL) 291 return ESRCH; 292 } 293 if (!PRISON_CHECK(curp->p_ucred, p->p_ucred)) { 294 PRELE(p); 295 return (ESRCH); 296 } 297 if (p->p_flags & P_SYSTEM) { 298 PRELE(p); 299 return EINVAL; 300 } 301 302 lwkt_gettoken(&p->p_token); 303 /* Can't trace a process that's currently exec'ing. */ 304 if ((p->p_flags & P_INEXEC) != 0) { 305 lwkt_reltoken(&p->p_token); 306 PRELE(p); 307 return EAGAIN; 308 } 309 310 /* 311 * Permissions check 312 */ 313 switch (req) { 314 case PT_TRACE_ME: 315 /* Always legal. */ 316 break; 317 318 case PT_ATTACH: 319 /* Self */ 320 if (p->p_pid == curp->p_pid) { 321 lwkt_reltoken(&p->p_token); 322 PRELE(p); 323 return EINVAL; 324 } 325 326 /* Already traced */ 327 if (p->p_flags & P_TRACED) { 328 lwkt_reltoken(&p->p_token); 329 PRELE(p); 330 return EBUSY; 331 } 332 333 if (curp->p_flags & P_TRACED) 334 for (pp = curp->p_pptr; pp != NULL; pp = pp->p_pptr) 335 if (pp == p) { 336 lwkt_reltoken(&p->p_token); 337 PRELE(p); 338 return (EINVAL); 339 } 340 341 /* not owned by you, has done setuid (unless you're root) */ 342 if ((p->p_ucred->cr_ruid != curp->p_ucred->cr_ruid) || 343 (p->p_flags & P_SUGID)) { 344 if ((error = priv_check_cred(curp->p_ucred, PRIV_ROOT, 0)) != 0) { 345 lwkt_reltoken(&p->p_token); 346 PRELE(p); 347 return error; 348 } 349 } 350 351 /* can't trace init when securelevel > 0 */ 352 if (securelevel > 0 && p->p_pid == 1) { 353 lwkt_reltoken(&p->p_token); 354 PRELE(p); 355 return EPERM; 356 } 357 358 /* OK */ 359 break; 360 361 case PT_READ_I: 362 case PT_READ_D: 363 case PT_WRITE_I: 364 case PT_WRITE_D: 365 case PT_IO: 366 case PT_CONTINUE: 367 case PT_KILL: 368 case PT_STEP: 369 case PT_DETACH: 370 #ifdef PT_GETREGS 371 case PT_GETREGS: 372 #endif 373 #ifdef PT_SETREGS 374 case PT_SETREGS: 375 #endif 376 #ifdef PT_GETFPREGS 377 case PT_GETFPREGS: 378 #endif 379 #ifdef PT_SETFPREGS 380 case PT_SETFPREGS: 381 #endif 382 #ifdef PT_GETDBREGS 383 case PT_GETDBREGS: 384 #endif 385 #ifdef PT_SETDBREGS 386 case PT_SETDBREGS: 387 #endif 388 /* not being traced... */ 389 if ((p->p_flags & P_TRACED) == 0) { 390 lwkt_reltoken(&p->p_token); 391 PRELE(p); 392 return EPERM; 393 } 394 395 /* not being traced by YOU */ 396 if (p->p_pptr != curp) { 397 lwkt_reltoken(&p->p_token); 398 PRELE(p); 399 return EBUSY; 400 } 401 402 /* not currently stopped */ 403 if (p->p_stat != SSTOP || 404 (p->p_flags & P_WAITED) == 0) { 405 lwkt_reltoken(&p->p_token); 406 PRELE(p); 407 return EBUSY; 408 } 409 410 /* OK */ 411 break; 412 413 default: 414 lwkt_reltoken(&p->p_token); 415 PRELE(p); 416 return EINVAL; 417 } 418 419 /* XXX lwp */ 420 lp = FIRST_LWP_IN_PROC(p); 421 #ifdef FIX_SSTEP 422 /* 423 * Single step fixup ala procfs 424 */ 425 FIX_SSTEP(lp); 426 #endif 427 428 /* 429 * Actually do the requests 430 */ 431 432 *res = 0; 433 434 switch (req) { 435 case PT_TRACE_ME: 436 /* set my trace flag and "owner" so it can read/write me */ 437 p->p_flags |= P_TRACED; 438 p->p_oppid = p->p_pptr->p_pid; 439 lwkt_reltoken(&p->p_token); 440 PRELE(p); 441 return 0; 442 443 case PT_ATTACH: 444 /* security check done above */ 445 p->p_flags |= P_TRACED; 446 p->p_oppid = p->p_pptr->p_pid; 447 proc_reparent(p, curp); 448 data = SIGSTOP; 449 goto sendsig; /* in PT_CONTINUE below */ 450 451 case PT_STEP: 452 case PT_CONTINUE: 453 case PT_DETACH: 454 /* Zero means do not send any signal */ 455 if (data < 0 || data > _SIG_MAXSIG) { 456 lwkt_reltoken(&p->p_token); 457 PRELE(p); 458 return EINVAL; 459 } 460 461 LWPHOLD(lp); 462 463 if (req == PT_STEP) { 464 if ((error = ptrace_single_step (lp))) { 465 LWPRELE(lp); 466 lwkt_reltoken(&p->p_token); 467 PRELE(p); 468 return error; 469 } 470 } 471 472 if (addr != (void *)1) { 473 if ((error = ptrace_set_pc (lp, 474 (u_long)(uintfptr_t)addr))) { 475 LWPRELE(lp); 476 lwkt_reltoken(&p->p_token); 477 PRELE(p); 478 return error; 479 } 480 } 481 LWPRELE(lp); 482 483 if (req == PT_DETACH) { 484 /* reset process parent */ 485 if (p->p_oppid != p->p_pptr->p_pid) { 486 struct proc *pp; 487 488 pp = pfind(p->p_oppid); 489 if (pp) { 490 proc_reparent(p, pp); 491 PRELE(pp); 492 } 493 } 494 495 p->p_flags &= ~(P_TRACED | P_WAITED); 496 p->p_oppid = 0; 497 498 /* should we send SIGCHLD? */ 499 } 500 501 sendsig: 502 /* 503 * Deliver or queue signal. If the process is stopped 504 * force it to be SACTIVE again. 505 */ 506 crit_enter(); 507 if (p->p_stat == SSTOP) { 508 p->p_xstat = data; 509 proc_unstop(p, SSTOP); 510 } else if (data) { 511 ksignal(p, data); 512 } 513 crit_exit(); 514 lwkt_reltoken(&p->p_token); 515 PRELE(p); 516 return 0; 517 518 case PT_WRITE_I: 519 case PT_WRITE_D: 520 write = 1; 521 /* fallthrough */ 522 case PT_READ_I: 523 case PT_READ_D: 524 /* 525 * NOTE! uio_offset represents the offset in the target 526 * process. The iov is in the current process (the guy 527 * making the ptrace call) so uio_td must be the current 528 * process (though for a SYSSPACE transfer it doesn't 529 * really matter). 530 */ 531 tmp = 0; 532 /* write = 0 set above */ 533 iov.iov_base = write ? (caddr_t)&data : (caddr_t)&tmp; 534 iov.iov_len = sizeof(int); 535 uio.uio_iov = &iov; 536 uio.uio_iovcnt = 1; 537 uio.uio_offset = (off_t)(uintptr_t)addr; 538 uio.uio_resid = sizeof(int); 539 uio.uio_segflg = UIO_SYSSPACE; 540 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 541 uio.uio_td = curthread; 542 error = procfs_domem(curp, lp, NULL, &uio); 543 if (uio.uio_resid != 0) { 544 /* 545 * XXX procfs_domem() doesn't currently return ENOSPC, 546 * so I think write() can bogusly return 0. 547 * XXX what happens for short writes? We don't want 548 * to write partial data. 549 * XXX procfs_domem() returns EPERM for other invalid 550 * addresses. Convert this to EINVAL. Does this 551 * clobber returns of EPERM for other reasons? 552 */ 553 if (error == 0 || error == ENOSPC || error == EPERM) 554 error = EINVAL; /* EOF */ 555 } 556 if (!write) 557 *res = tmp; 558 lwkt_reltoken(&p->p_token); 559 PRELE(p); 560 return (error); 561 562 case PT_IO: 563 /* 564 * NOTE! uio_offset represents the offset in the target 565 * process. The iov is in the current process (the guy 566 * making the ptrace call) so uio_td must be the current 567 * process. 568 */ 569 piod = addr; 570 iov.iov_base = piod->piod_addr; 571 iov.iov_len = piod->piod_len; 572 uio.uio_iov = &iov; 573 uio.uio_iovcnt = 1; 574 uio.uio_offset = (off_t)(uintptr_t)piod->piod_offs; 575 uio.uio_resid = piod->piod_len; 576 uio.uio_segflg = UIO_USERSPACE; 577 uio.uio_td = curthread; 578 switch (piod->piod_op) { 579 case PIOD_READ_D: 580 case PIOD_READ_I: 581 uio.uio_rw = UIO_READ; 582 break; 583 case PIOD_WRITE_D: 584 case PIOD_WRITE_I: 585 uio.uio_rw = UIO_WRITE; 586 break; 587 default: 588 lwkt_reltoken(&p->p_token); 589 PRELE(p); 590 return (EINVAL); 591 } 592 error = procfs_domem(curp, lp, NULL, &uio); 593 piod->piod_len -= uio.uio_resid; 594 lwkt_reltoken(&p->p_token); 595 PRELE(p); 596 return (error); 597 598 case PT_KILL: 599 data = SIGKILL; 600 goto sendsig; /* in PT_CONTINUE above */ 601 602 #ifdef PT_SETREGS 603 case PT_SETREGS: 604 write = 1; 605 /* fallthrough */ 606 #endif /* PT_SETREGS */ 607 #ifdef PT_GETREGS 608 case PT_GETREGS: 609 /* write = 0 above */ 610 #endif /* PT_SETREGS */ 611 #if defined(PT_SETREGS) || defined(PT_GETREGS) 612 if (!procfs_validregs(lp)) { 613 lwkt_reltoken(&p->p_token); 614 PRELE(p); 615 return EINVAL; 616 } else { 617 iov.iov_base = addr; 618 iov.iov_len = sizeof(struct reg); 619 uio.uio_iov = &iov; 620 uio.uio_iovcnt = 1; 621 uio.uio_offset = 0; 622 uio.uio_resid = sizeof(struct reg); 623 uio.uio_segflg = UIO_SYSSPACE; 624 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 625 uio.uio_td = curthread; 626 t = procfs_doregs(curp, lp, NULL, &uio); 627 lwkt_reltoken(&p->p_token); 628 PRELE(p); 629 return t; 630 } 631 #endif /* defined(PT_SETREGS) || defined(PT_GETREGS) */ 632 633 #ifdef PT_SETFPREGS 634 case PT_SETFPREGS: 635 write = 1; 636 /* fallthrough */ 637 #endif /* PT_SETFPREGS */ 638 #ifdef PT_GETFPREGS 639 case PT_GETFPREGS: 640 /* write = 0 above */ 641 #endif /* PT_SETFPREGS */ 642 #if defined(PT_SETFPREGS) || defined(PT_GETFPREGS) 643 if (!procfs_validfpregs(lp)) { 644 lwkt_reltoken(&p->p_token); 645 PRELE(p); 646 return EINVAL; 647 } else { 648 iov.iov_base = addr; 649 iov.iov_len = sizeof(struct fpreg); 650 uio.uio_iov = &iov; 651 uio.uio_iovcnt = 1; 652 uio.uio_offset = 0; 653 uio.uio_resid = sizeof(struct fpreg); 654 uio.uio_segflg = UIO_SYSSPACE; 655 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 656 uio.uio_td = curthread; 657 t = procfs_dofpregs(curp, lp, NULL, &uio); 658 lwkt_reltoken(&p->p_token); 659 PRELE(p); 660 return t; 661 } 662 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */ 663 664 #ifdef PT_SETDBREGS 665 case PT_SETDBREGS: 666 write = 1; 667 /* fallthrough */ 668 #endif /* PT_SETDBREGS */ 669 #ifdef PT_GETDBREGS 670 case PT_GETDBREGS: 671 /* write = 0 above */ 672 #endif /* PT_SETDBREGS */ 673 #if defined(PT_SETDBREGS) || defined(PT_GETDBREGS) 674 if (!procfs_validdbregs(lp)) { 675 lwkt_reltoken(&p->p_token); 676 PRELE(p); 677 return EINVAL; 678 } else { 679 iov.iov_base = addr; 680 iov.iov_len = sizeof(struct dbreg); 681 uio.uio_iov = &iov; 682 uio.uio_iovcnt = 1; 683 uio.uio_offset = 0; 684 uio.uio_resid = sizeof(struct dbreg); 685 uio.uio_segflg = UIO_SYSSPACE; 686 uio.uio_rw = write ? UIO_WRITE : UIO_READ; 687 uio.uio_td = curthread; 688 t = procfs_dodbregs(curp, lp, NULL, &uio); 689 lwkt_reltoken(&p->p_token); 690 PRELE(p); 691 return t; 692 } 693 #endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */ 694 695 default: 696 break; 697 } 698 699 lwkt_reltoken(&p->p_token); 700 PRELE(p); 701 702 return 0; 703 } 704 705 int 706 trace_req(struct proc *p) 707 { 708 return 1; 709 } 710 711 /* 712 * stopevent() 713 * 714 * Stop a process because of a procfs event. Stay stopped until p->p_step 715 * is cleared (cleared by PIOCCONT in procfs). 716 * 717 * MPSAFE 718 */ 719 void 720 stopevent(struct proc *p, unsigned int event, unsigned int val) 721 { 722 /* 723 * Set event info. Recheck p_stops in case we are 724 * racing a close() on procfs. 725 */ 726 spin_lock(&p->p_spin); 727 if ((p->p_stops & event) == 0) { 728 spin_unlock(&p->p_spin); 729 return; 730 } 731 p->p_xstat = val; 732 p->p_stype = event; 733 p->p_step = 1; 734 tsleep_interlock(&p->p_step, 0); 735 spin_unlock(&p->p_spin); 736 737 /* 738 * Wakeup any PIOCWAITing procs and wait for p_step to 739 * be cleared. 740 */ 741 for (;;) { 742 wakeup(&p->p_stype); 743 tsleep(&p->p_step, PINTERLOCKED, "stopevent", 0); 744 spin_lock(&p->p_spin); 745 if (p->p_step == 0) { 746 spin_unlock(&p->p_spin); 747 break; 748 } 749 tsleep_interlock(&p->p_step, 0); 750 spin_unlock(&p->p_spin); 751 } 752 } 753 754