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