1 /* 2 * Copyright (c) 1996 John S. Dyson 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 immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 * 19 * $FreeBSD$ 20 */ 21 22 /* 23 * This file contains a high-performance replacement for the socket-based 24 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support 25 * all features of sockets, but does do everything that pipes normally 26 * do. 27 */ 28 29 /* 30 * This code has two modes of operation, a small write mode and a large 31 * write mode. The small write mode acts like conventional pipes with 32 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the 33 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT 34 * and PIPE_SIZE in size, it is fully mapped and wired into the kernel, and 35 * the receiving process can copy it directly from the pages in the sending 36 * process. 37 * 38 * If the sending process receives a signal, it is possible that it will 39 * go away, and certainly its address space can change, because control 40 * is returned back to the user-mode side. In that case, the pipe code 41 * arranges to copy the buffer supplied by the user process, to a pageable 42 * kernel buffer, and the receiving process will grab the data from the 43 * pageable kernel buffer. Since signals don't happen all that often, 44 * the copy operation is normally eliminated. 45 * 46 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will 47 * happen for small transfers so that the system will not spend all of 48 * its time context switching. PIPE_SIZE is constrained by the 49 * amount of kernel virtual memory. 50 */ 51 52 #include "opt_mac.h" 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/fcntl.h> 57 #include <sys/file.h> 58 #include <sys/filedesc.h> 59 #include <sys/filio.h> 60 #include <sys/kernel.h> 61 #include <sys/lock.h> 62 #include <sys/mac.h> 63 #include <sys/mutex.h> 64 #include <sys/ttycom.h> 65 #include <sys/stat.h> 66 #include <sys/malloc.h> 67 #include <sys/poll.h> 68 #include <sys/selinfo.h> 69 #include <sys/signalvar.h> 70 #include <sys/sysproto.h> 71 #include <sys/pipe.h> 72 #include <sys/proc.h> 73 #include <sys/vnode.h> 74 #include <sys/uio.h> 75 #include <sys/event.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <vm/vm_object.h> 80 #include <vm/vm_kern.h> 81 #include <vm/vm_extern.h> 82 #include <vm/pmap.h> 83 #include <vm/vm_map.h> 84 #include <vm/vm_page.h> 85 #include <vm/uma.h> 86 87 /* 88 * Use this define if you want to disable *fancy* VM things. Expect an 89 * approx 30% decrease in transfer rate. This could be useful for 90 * NetBSD or OpenBSD. 91 */ 92 /* #define PIPE_NODIRECT */ 93 94 /* 95 * interfaces to the outside world 96 */ 97 static fo_rdwr_t pipe_read; 98 static fo_rdwr_t pipe_write; 99 static fo_ioctl_t pipe_ioctl; 100 static fo_poll_t pipe_poll; 101 static fo_kqfilter_t pipe_kqfilter; 102 static fo_stat_t pipe_stat; 103 static fo_close_t pipe_close; 104 105 static struct fileops pipeops = { 106 pipe_read, pipe_write, pipe_ioctl, pipe_poll, pipe_kqfilter, 107 pipe_stat, pipe_close 108 }; 109 110 static void filt_pipedetach(struct knote *kn); 111 static int filt_piperead(struct knote *kn, long hint); 112 static int filt_pipewrite(struct knote *kn, long hint); 113 114 static struct filterops pipe_rfiltops = 115 { 1, NULL, filt_pipedetach, filt_piperead }; 116 static struct filterops pipe_wfiltops = 117 { 1, NULL, filt_pipedetach, filt_pipewrite }; 118 119 #define PIPE_GET_GIANT(pipe) \ 120 do { \ 121 KASSERT(((pipe)->pipe_state & PIPE_LOCKFL) != 0, \ 122 ("%s:%d PIPE_GET_GIANT: line pipe not locked", \ 123 __FILE__, __LINE__)); \ 124 PIPE_UNLOCK(pipe); \ 125 mtx_lock(&Giant); \ 126 } while (0) 127 128 #define PIPE_DROP_GIANT(pipe) \ 129 do { \ 130 mtx_unlock(&Giant); \ 131 PIPE_LOCK(pipe); \ 132 } while (0) 133 134 /* 135 * Default pipe buffer size(s), this can be kind-of large now because pipe 136 * space is pageable. The pipe code will try to maintain locality of 137 * reference for performance reasons, so small amounts of outstanding I/O 138 * will not wipe the cache. 139 */ 140 #define MINPIPESIZE (PIPE_SIZE/3) 141 #define MAXPIPESIZE (2*PIPE_SIZE/3) 142 143 /* 144 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but 145 * is there so that on large systems, we don't exhaust it. 146 */ 147 #define MAXPIPEKVA (8*1024*1024) 148 149 /* 150 * Limit for direct transfers, we cannot, of course limit 151 * the amount of kva for pipes in general though. 152 */ 153 #define LIMITPIPEKVA (16*1024*1024) 154 155 /* 156 * Limit the number of "big" pipes 157 */ 158 #define LIMITBIGPIPES 32 159 static int nbigpipe; 160 161 static int amountpipekva; 162 163 static void pipeinit(void *dummy __unused); 164 static void pipeclose(struct pipe *cpipe); 165 static void pipe_free_kmem(struct pipe *cpipe); 166 static int pipe_create(struct pipe **cpipep); 167 static __inline int pipelock(struct pipe *cpipe, int catch); 168 static __inline void pipeunlock(struct pipe *cpipe); 169 static __inline void pipeselwakeup(struct pipe *cpipe); 170 #ifndef PIPE_NODIRECT 171 static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio); 172 static void pipe_destroy_write_buffer(struct pipe *wpipe); 173 static int pipe_direct_write(struct pipe *wpipe, struct uio *uio); 174 static void pipe_clone_write_buffer(struct pipe *wpipe); 175 #endif 176 static int pipespace(struct pipe *cpipe, int size); 177 178 static uma_zone_t pipe_zone; 179 180 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL); 181 182 static void 183 pipeinit(void *dummy __unused) 184 { 185 pipe_zone = uma_zcreate("PIPE", sizeof(struct pipe), NULL, 186 NULL, NULL, NULL, UMA_ALIGN_PTR, 0); 187 } 188 189 /* 190 * The pipe system call for the DTYPE_PIPE type of pipes 191 */ 192 193 /* ARGSUSED */ 194 int 195 pipe(td, uap) 196 struct thread *td; 197 struct pipe_args /* { 198 int dummy; 199 } */ *uap; 200 { 201 struct filedesc *fdp = td->td_proc->p_fd; 202 struct file *rf, *wf; 203 struct pipe *rpipe, *wpipe; 204 struct mtx *pmtx; 205 int fd, error; 206 207 KASSERT(pipe_zone != NULL, ("pipe_zone not initialized")); 208 209 pmtx = malloc(sizeof(*pmtx), M_TEMP, M_ZERO); 210 211 rpipe = wpipe = NULL; 212 if (pipe_create(&rpipe) || pipe_create(&wpipe)) { 213 pipeclose(rpipe); 214 pipeclose(wpipe); 215 free(pmtx, M_TEMP); 216 return (ENFILE); 217 } 218 219 rpipe->pipe_state |= PIPE_DIRECTOK; 220 wpipe->pipe_state |= PIPE_DIRECTOK; 221 222 error = falloc(td, &rf, &fd); 223 if (error) { 224 pipeclose(rpipe); 225 pipeclose(wpipe); 226 free(pmtx, M_TEMP); 227 return (error); 228 } 229 fhold(rf); 230 td->td_retval[0] = fd; 231 232 /* 233 * Warning: once we've gotten past allocation of the fd for the 234 * read-side, we can only drop the read side via fdrop() in order 235 * to avoid races against processes which manage to dup() the read 236 * side while we are blocked trying to allocate the write side. 237 */ 238 FILE_LOCK(rf); 239 rf->f_flag = FREAD | FWRITE; 240 rf->f_type = DTYPE_PIPE; 241 rf->f_data = rpipe; 242 rf->f_ops = &pipeops; 243 FILE_UNLOCK(rf); 244 error = falloc(td, &wf, &fd); 245 if (error) { 246 FILEDESC_LOCK(fdp); 247 if (fdp->fd_ofiles[td->td_retval[0]] == rf) { 248 fdp->fd_ofiles[td->td_retval[0]] = NULL; 249 FILEDESC_UNLOCK(fdp); 250 fdrop(rf, td); 251 } else 252 FILEDESC_UNLOCK(fdp); 253 fdrop(rf, td); 254 /* rpipe has been closed by fdrop(). */ 255 pipeclose(wpipe); 256 free(pmtx, M_TEMP); 257 return (error); 258 } 259 FILE_LOCK(wf); 260 wf->f_flag = FREAD | FWRITE; 261 wf->f_type = DTYPE_PIPE; 262 wf->f_data = wpipe; 263 wf->f_ops = &pipeops; 264 FILE_UNLOCK(wf); 265 td->td_retval[1] = fd; 266 rpipe->pipe_peer = wpipe; 267 wpipe->pipe_peer = rpipe; 268 #ifdef MAC 269 /* 270 * struct pipe represents a pipe endpoint. The MAC label is shared 271 * between the connected endpoints. As a result mac_init_pipe() and 272 * mac_create_pipe() should only be called on one of the endpoints 273 * after they have been connected. 274 */ 275 mac_init_pipe(rpipe); 276 mac_create_pipe(td->td_ucred, rpipe); 277 #endif 278 mtx_init(pmtx, "pipe mutex", NULL, MTX_DEF | MTX_RECURSE); 279 rpipe->pipe_mtxp = wpipe->pipe_mtxp = pmtx; 280 fdrop(rf, td); 281 282 return (0); 283 } 284 285 /* 286 * Allocate kva for pipe circular buffer, the space is pageable 287 * This routine will 'realloc' the size of a pipe safely, if it fails 288 * it will retain the old buffer. 289 * If it fails it will return ENOMEM. 290 */ 291 static int 292 pipespace(cpipe, size) 293 struct pipe *cpipe; 294 int size; 295 { 296 struct vm_object *object; 297 caddr_t buffer; 298 int npages, error; 299 300 GIANT_REQUIRED; 301 KASSERT(cpipe->pipe_mtxp == NULL || !mtx_owned(PIPE_MTX(cpipe)), 302 ("pipespace: pipe mutex locked")); 303 304 npages = round_page(size)/PAGE_SIZE; 305 /* 306 * Create an object, I don't like the idea of paging to/from 307 * kernel_object. 308 * XXX -- minor change needed here for NetBSD/OpenBSD VM systems. 309 */ 310 object = vm_object_allocate(OBJT_DEFAULT, npages); 311 buffer = (caddr_t) vm_map_min(kernel_map); 312 313 /* 314 * Insert the object into the kernel map, and allocate kva for it. 315 * The map entry is, by default, pageable. 316 * XXX -- minor change needed here for NetBSD/OpenBSD VM systems. 317 */ 318 error = vm_map_find(kernel_map, object, 0, 319 (vm_offset_t *) &buffer, size, 1, 320 VM_PROT_ALL, VM_PROT_ALL, 0); 321 322 if (error != KERN_SUCCESS) { 323 vm_object_deallocate(object); 324 return (ENOMEM); 325 } 326 327 /* free old resources if we're resizing */ 328 pipe_free_kmem(cpipe); 329 cpipe->pipe_buffer.object = object; 330 cpipe->pipe_buffer.buffer = buffer; 331 cpipe->pipe_buffer.size = size; 332 cpipe->pipe_buffer.in = 0; 333 cpipe->pipe_buffer.out = 0; 334 cpipe->pipe_buffer.cnt = 0; 335 amountpipekva += cpipe->pipe_buffer.size; 336 return (0); 337 } 338 339 /* 340 * initialize and allocate VM and memory for pipe 341 */ 342 static int 343 pipe_create(cpipep) 344 struct pipe **cpipep; 345 { 346 struct pipe *cpipe; 347 int error; 348 349 *cpipep = uma_zalloc(pipe_zone, 0); 350 if (*cpipep == NULL) 351 return (ENOMEM); 352 353 cpipe = *cpipep; 354 355 /* so pipespace()->pipe_free_kmem() doesn't follow junk pointer */ 356 cpipe->pipe_buffer.object = NULL; 357 #ifndef PIPE_NODIRECT 358 cpipe->pipe_map.kva = 0; 359 #endif 360 /* 361 * protect so pipeclose() doesn't follow a junk pointer 362 * if pipespace() fails. 363 */ 364 bzero(&cpipe->pipe_sel, sizeof(cpipe->pipe_sel)); 365 cpipe->pipe_state = 0; 366 cpipe->pipe_peer = NULL; 367 cpipe->pipe_busy = 0; 368 369 #ifndef PIPE_NODIRECT 370 /* 371 * pipe data structure initializations to support direct pipe I/O 372 */ 373 cpipe->pipe_map.cnt = 0; 374 cpipe->pipe_map.kva = 0; 375 cpipe->pipe_map.pos = 0; 376 cpipe->pipe_map.npages = 0; 377 /* cpipe->pipe_map.ms[] = invalid */ 378 #endif 379 380 cpipe->pipe_mtxp = NULL; /* avoid pipespace assertion */ 381 error = pipespace(cpipe, PIPE_SIZE); 382 if (error) 383 return (error); 384 385 vfs_timestamp(&cpipe->pipe_ctime); 386 cpipe->pipe_atime = cpipe->pipe_ctime; 387 cpipe->pipe_mtime = cpipe->pipe_ctime; 388 389 return (0); 390 } 391 392 393 /* 394 * lock a pipe for I/O, blocking other access 395 */ 396 static __inline int 397 pipelock(cpipe, catch) 398 struct pipe *cpipe; 399 int catch; 400 { 401 int error; 402 403 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 404 while (cpipe->pipe_state & PIPE_LOCKFL) { 405 cpipe->pipe_state |= PIPE_LWANT; 406 error = msleep(cpipe, PIPE_MTX(cpipe), 407 catch ? (PRIBIO | PCATCH) : PRIBIO, 408 "pipelk", 0); 409 if (error != 0) 410 return (error); 411 } 412 cpipe->pipe_state |= PIPE_LOCKFL; 413 return (0); 414 } 415 416 /* 417 * unlock a pipe I/O lock 418 */ 419 static __inline void 420 pipeunlock(cpipe) 421 struct pipe *cpipe; 422 { 423 424 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 425 cpipe->pipe_state &= ~PIPE_LOCKFL; 426 if (cpipe->pipe_state & PIPE_LWANT) { 427 cpipe->pipe_state &= ~PIPE_LWANT; 428 wakeup(cpipe); 429 } 430 } 431 432 static __inline void 433 pipeselwakeup(cpipe) 434 struct pipe *cpipe; 435 { 436 437 if (cpipe->pipe_state & PIPE_SEL) { 438 cpipe->pipe_state &= ~PIPE_SEL; 439 selwakeup(&cpipe->pipe_sel); 440 } 441 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) 442 pgsigio(&cpipe->pipe_sigio, SIGIO, 0); 443 KNOTE(&cpipe->pipe_sel.si_note, 0); 444 } 445 446 /* ARGSUSED */ 447 static int 448 pipe_read(fp, uio, active_cred, flags, td) 449 struct file *fp; 450 struct uio *uio; 451 struct ucred *active_cred; 452 struct thread *td; 453 int flags; 454 { 455 struct pipe *rpipe = fp->f_data; 456 int error; 457 int nread = 0; 458 u_int size; 459 460 PIPE_LOCK(rpipe); 461 ++rpipe->pipe_busy; 462 error = pipelock(rpipe, 1); 463 if (error) 464 goto unlocked_error; 465 466 #ifdef MAC 467 error = mac_check_pipe_read(active_cred, rpipe); 468 if (error) 469 goto locked_error; 470 #endif 471 472 while (uio->uio_resid) { 473 /* 474 * normal pipe buffer receive 475 */ 476 if (rpipe->pipe_buffer.cnt > 0) { 477 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 478 if (size > rpipe->pipe_buffer.cnt) 479 size = rpipe->pipe_buffer.cnt; 480 if (size > (u_int) uio->uio_resid) 481 size = (u_int) uio->uio_resid; 482 483 PIPE_UNLOCK(rpipe); 484 error = uiomove(&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 485 size, uio); 486 PIPE_LOCK(rpipe); 487 if (error) 488 break; 489 490 rpipe->pipe_buffer.out += size; 491 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 492 rpipe->pipe_buffer.out = 0; 493 494 rpipe->pipe_buffer.cnt -= size; 495 496 /* 497 * If there is no more to read in the pipe, reset 498 * its pointers to the beginning. This improves 499 * cache hit stats. 500 */ 501 if (rpipe->pipe_buffer.cnt == 0) { 502 rpipe->pipe_buffer.in = 0; 503 rpipe->pipe_buffer.out = 0; 504 } 505 nread += size; 506 #ifndef PIPE_NODIRECT 507 /* 508 * Direct copy, bypassing a kernel buffer. 509 */ 510 } else if ((size = rpipe->pipe_map.cnt) && 511 (rpipe->pipe_state & PIPE_DIRECTW)) { 512 caddr_t va; 513 if (size > (u_int) uio->uio_resid) 514 size = (u_int) uio->uio_resid; 515 516 va = (caddr_t) rpipe->pipe_map.kva + 517 rpipe->pipe_map.pos; 518 PIPE_UNLOCK(rpipe); 519 error = uiomove(va, size, uio); 520 PIPE_LOCK(rpipe); 521 if (error) 522 break; 523 nread += size; 524 rpipe->pipe_map.pos += size; 525 rpipe->pipe_map.cnt -= size; 526 if (rpipe->pipe_map.cnt == 0) { 527 rpipe->pipe_state &= ~PIPE_DIRECTW; 528 wakeup(rpipe); 529 } 530 #endif 531 } else { 532 /* 533 * detect EOF condition 534 * read returns 0 on EOF, no need to set error 535 */ 536 if (rpipe->pipe_state & PIPE_EOF) 537 break; 538 539 /* 540 * If the "write-side" has been blocked, wake it up now. 541 */ 542 if (rpipe->pipe_state & PIPE_WANTW) { 543 rpipe->pipe_state &= ~PIPE_WANTW; 544 wakeup(rpipe); 545 } 546 547 /* 548 * Break if some data was read. 549 */ 550 if (nread > 0) 551 break; 552 553 /* 554 * Unlock the pipe buffer for our remaining processing. We 555 * will either break out with an error or we will sleep and 556 * relock to loop. 557 */ 558 pipeunlock(rpipe); 559 560 /* 561 * Handle non-blocking mode operation or 562 * wait for more data. 563 */ 564 if (fp->f_flag & FNONBLOCK) { 565 error = EAGAIN; 566 } else { 567 rpipe->pipe_state |= PIPE_WANTR; 568 if ((error = msleep(rpipe, PIPE_MTX(rpipe), 569 PRIBIO | PCATCH, 570 "piperd", 0)) == 0) 571 error = pipelock(rpipe, 1); 572 } 573 if (error) 574 goto unlocked_error; 575 } 576 } 577 #ifdef MAC 578 locked_error: 579 #endif 580 pipeunlock(rpipe); 581 582 /* XXX: should probably do this before getting any locks. */ 583 if (error == 0) 584 vfs_timestamp(&rpipe->pipe_atime); 585 unlocked_error: 586 --rpipe->pipe_busy; 587 588 /* 589 * PIPE_WANT processing only makes sense if pipe_busy is 0. 590 */ 591 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 592 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 593 wakeup(rpipe); 594 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 595 /* 596 * Handle write blocking hysteresis. 597 */ 598 if (rpipe->pipe_state & PIPE_WANTW) { 599 rpipe->pipe_state &= ~PIPE_WANTW; 600 wakeup(rpipe); 601 } 602 } 603 604 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 605 pipeselwakeup(rpipe); 606 607 PIPE_UNLOCK(rpipe); 608 return (error); 609 } 610 611 #ifndef PIPE_NODIRECT 612 /* 613 * Map the sending processes' buffer into kernel space and wire it. 614 * This is similar to a physical write operation. 615 */ 616 static int 617 pipe_build_write_buffer(wpipe, uio) 618 struct pipe *wpipe; 619 struct uio *uio; 620 { 621 u_int size; 622 int i; 623 vm_offset_t addr, endaddr, paddr; 624 625 GIANT_REQUIRED; 626 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 627 628 size = (u_int) uio->uio_iov->iov_len; 629 if (size > wpipe->pipe_buffer.size) 630 size = wpipe->pipe_buffer.size; 631 632 endaddr = round_page((vm_offset_t)uio->uio_iov->iov_base + size); 633 addr = trunc_page((vm_offset_t)uio->uio_iov->iov_base); 634 for (i = 0; addr < endaddr; addr += PAGE_SIZE, i++) { 635 vm_page_t m; 636 637 /* 638 * vm_fault_quick() can sleep. Consequently, 639 * vm_page_lock_queue() and vm_page_unlock_queue() 640 * should not be performed outside of this loop. 641 */ 642 if (vm_fault_quick((caddr_t)addr, VM_PROT_READ) < 0 || 643 (paddr = pmap_extract(vmspace_pmap(curproc->p_vmspace), 644 addr)) == 0) { 645 int j; 646 647 vm_page_lock_queues(); 648 for (j = 0; j < i; j++) 649 vm_page_unwire(wpipe->pipe_map.ms[j], 1); 650 vm_page_unlock_queues(); 651 return (EFAULT); 652 } 653 654 m = PHYS_TO_VM_PAGE(paddr); 655 vm_page_lock_queues(); 656 vm_page_wire(m); 657 vm_page_unlock_queues(); 658 wpipe->pipe_map.ms[i] = m; 659 } 660 661 /* 662 * set up the control block 663 */ 664 wpipe->pipe_map.npages = i; 665 wpipe->pipe_map.pos = 666 ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; 667 wpipe->pipe_map.cnt = size; 668 669 /* 670 * and map the buffer 671 */ 672 if (wpipe->pipe_map.kva == 0) { 673 /* 674 * We need to allocate space for an extra page because the 675 * address range might (will) span pages at times. 676 */ 677 wpipe->pipe_map.kva = kmem_alloc_pageable(kernel_map, 678 wpipe->pipe_buffer.size + PAGE_SIZE); 679 amountpipekva += wpipe->pipe_buffer.size + PAGE_SIZE; 680 } 681 pmap_qenter(wpipe->pipe_map.kva, wpipe->pipe_map.ms, 682 wpipe->pipe_map.npages); 683 684 /* 685 * and update the uio data 686 */ 687 688 uio->uio_iov->iov_len -= size; 689 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; 690 if (uio->uio_iov->iov_len == 0) 691 uio->uio_iov++; 692 uio->uio_resid -= size; 693 uio->uio_offset += size; 694 return (0); 695 } 696 697 /* 698 * unmap and unwire the process buffer 699 */ 700 static void 701 pipe_destroy_write_buffer(wpipe) 702 struct pipe *wpipe; 703 { 704 int i; 705 706 GIANT_REQUIRED; 707 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 708 709 if (wpipe->pipe_map.kva) { 710 pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages); 711 712 if (amountpipekva > MAXPIPEKVA) { 713 vm_offset_t kva = wpipe->pipe_map.kva; 714 wpipe->pipe_map.kva = 0; 715 kmem_free(kernel_map, kva, 716 wpipe->pipe_buffer.size + PAGE_SIZE); 717 amountpipekva -= wpipe->pipe_buffer.size + PAGE_SIZE; 718 } 719 } 720 vm_page_lock_queues(); 721 for (i = 0; i < wpipe->pipe_map.npages; i++) 722 vm_page_unwire(wpipe->pipe_map.ms[i], 1); 723 vm_page_unlock_queues(); 724 wpipe->pipe_map.npages = 0; 725 } 726 727 /* 728 * In the case of a signal, the writing process might go away. This 729 * code copies the data into the circular buffer so that the source 730 * pages can be freed without loss of data. 731 */ 732 static void 733 pipe_clone_write_buffer(wpipe) 734 struct pipe *wpipe; 735 { 736 int size; 737 int pos; 738 739 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 740 size = wpipe->pipe_map.cnt; 741 pos = wpipe->pipe_map.pos; 742 743 wpipe->pipe_buffer.in = size; 744 wpipe->pipe_buffer.out = 0; 745 wpipe->pipe_buffer.cnt = size; 746 wpipe->pipe_state &= ~PIPE_DIRECTW; 747 748 PIPE_GET_GIANT(wpipe); 749 bcopy((caddr_t) wpipe->pipe_map.kva + pos, 750 wpipe->pipe_buffer.buffer, size); 751 pipe_destroy_write_buffer(wpipe); 752 PIPE_DROP_GIANT(wpipe); 753 } 754 755 /* 756 * This implements the pipe buffer write mechanism. Note that only 757 * a direct write OR a normal pipe write can be pending at any given time. 758 * If there are any characters in the pipe buffer, the direct write will 759 * be deferred until the receiving process grabs all of the bytes from 760 * the pipe buffer. Then the direct mapping write is set-up. 761 */ 762 static int 763 pipe_direct_write(wpipe, uio) 764 struct pipe *wpipe; 765 struct uio *uio; 766 { 767 int error; 768 769 retry: 770 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 771 while (wpipe->pipe_state & PIPE_DIRECTW) { 772 if (wpipe->pipe_state & PIPE_WANTR) { 773 wpipe->pipe_state &= ~PIPE_WANTR; 774 wakeup(wpipe); 775 } 776 wpipe->pipe_state |= PIPE_WANTW; 777 error = msleep(wpipe, PIPE_MTX(wpipe), 778 PRIBIO | PCATCH, "pipdww", 0); 779 if (error) 780 goto error1; 781 if (wpipe->pipe_state & PIPE_EOF) { 782 error = EPIPE; 783 goto error1; 784 } 785 } 786 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 787 if (wpipe->pipe_buffer.cnt > 0) { 788 if (wpipe->pipe_state & PIPE_WANTR) { 789 wpipe->pipe_state &= ~PIPE_WANTR; 790 wakeup(wpipe); 791 } 792 793 wpipe->pipe_state |= PIPE_WANTW; 794 error = msleep(wpipe, PIPE_MTX(wpipe), 795 PRIBIO | PCATCH, "pipdwc", 0); 796 if (error) 797 goto error1; 798 if (wpipe->pipe_state & PIPE_EOF) { 799 error = EPIPE; 800 goto error1; 801 } 802 goto retry; 803 } 804 805 wpipe->pipe_state |= PIPE_DIRECTW; 806 807 pipelock(wpipe, 0); 808 PIPE_GET_GIANT(wpipe); 809 error = pipe_build_write_buffer(wpipe, uio); 810 PIPE_DROP_GIANT(wpipe); 811 pipeunlock(wpipe); 812 if (error) { 813 wpipe->pipe_state &= ~PIPE_DIRECTW; 814 goto error1; 815 } 816 817 error = 0; 818 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 819 if (wpipe->pipe_state & PIPE_EOF) { 820 pipelock(wpipe, 0); 821 PIPE_GET_GIANT(wpipe); 822 pipe_destroy_write_buffer(wpipe); 823 PIPE_DROP_GIANT(wpipe); 824 pipeunlock(wpipe); 825 pipeselwakeup(wpipe); 826 error = EPIPE; 827 goto error1; 828 } 829 if (wpipe->pipe_state & PIPE_WANTR) { 830 wpipe->pipe_state &= ~PIPE_WANTR; 831 wakeup(wpipe); 832 } 833 pipeselwakeup(wpipe); 834 error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, 835 "pipdwt", 0); 836 } 837 838 pipelock(wpipe,0); 839 if (wpipe->pipe_state & PIPE_DIRECTW) { 840 /* 841 * this bit of trickery substitutes a kernel buffer for 842 * the process that might be going away. 843 */ 844 pipe_clone_write_buffer(wpipe); 845 } else { 846 PIPE_GET_GIANT(wpipe); 847 pipe_destroy_write_buffer(wpipe); 848 PIPE_DROP_GIANT(wpipe); 849 } 850 pipeunlock(wpipe); 851 return (error); 852 853 error1: 854 wakeup(wpipe); 855 return (error); 856 } 857 #endif 858 859 static int 860 pipe_write(fp, uio, active_cred, flags, td) 861 struct file *fp; 862 struct uio *uio; 863 struct ucred *active_cred; 864 struct thread *td; 865 int flags; 866 { 867 int error = 0; 868 int orig_resid; 869 struct pipe *wpipe, *rpipe; 870 871 rpipe = fp->f_data; 872 wpipe = rpipe->pipe_peer; 873 874 PIPE_LOCK(rpipe); 875 /* 876 * detect loss of pipe read side, issue SIGPIPE if lost. 877 */ 878 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 879 PIPE_UNLOCK(rpipe); 880 return (EPIPE); 881 } 882 #ifdef MAC 883 error = mac_check_pipe_write(active_cred, wpipe); 884 if (error) { 885 PIPE_UNLOCK(rpipe); 886 return (error); 887 } 888 #endif 889 ++wpipe->pipe_busy; 890 891 /* 892 * If it is advantageous to resize the pipe buffer, do 893 * so. 894 */ 895 if ((uio->uio_resid > PIPE_SIZE) && 896 (nbigpipe < LIMITBIGPIPES) && 897 (wpipe->pipe_state & PIPE_DIRECTW) == 0 && 898 (wpipe->pipe_buffer.size <= PIPE_SIZE) && 899 (wpipe->pipe_buffer.cnt == 0)) { 900 901 if ((error = pipelock(wpipe, 1)) == 0) { 902 PIPE_GET_GIANT(wpipe); 903 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 904 nbigpipe++; 905 PIPE_DROP_GIANT(wpipe); 906 pipeunlock(wpipe); 907 } 908 } 909 910 /* 911 * If an early error occured unbusy and return, waking up any pending 912 * readers. 913 */ 914 if (error) { 915 --wpipe->pipe_busy; 916 if ((wpipe->pipe_busy == 0) && 917 (wpipe->pipe_state & PIPE_WANT)) { 918 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 919 wakeup(wpipe); 920 } 921 PIPE_UNLOCK(rpipe); 922 return(error); 923 } 924 925 orig_resid = uio->uio_resid; 926 927 while (uio->uio_resid) { 928 int space; 929 930 #ifndef PIPE_NODIRECT 931 /* 932 * If the transfer is large, we can gain performance if 933 * we do process-to-process copies directly. 934 * If the write is non-blocking, we don't use the 935 * direct write mechanism. 936 * 937 * The direct write mechanism will detect the reader going 938 * away on us. 939 */ 940 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && 941 (fp->f_flag & FNONBLOCK) == 0 && 942 (wpipe->pipe_map.kva || (amountpipekva < LIMITPIPEKVA)) && 943 (uio->uio_iov->iov_len >= PIPE_MINDIRECT)) { 944 error = pipe_direct_write(wpipe, uio); 945 if (error) 946 break; 947 continue; 948 } 949 #endif 950 951 /* 952 * Pipe buffered writes cannot be coincidental with 953 * direct writes. We wait until the currently executing 954 * direct write is completed before we start filling the 955 * pipe buffer. We break out if a signal occurs or the 956 * reader goes away. 957 */ 958 retrywrite: 959 while (wpipe->pipe_state & PIPE_DIRECTW) { 960 if (wpipe->pipe_state & PIPE_WANTR) { 961 wpipe->pipe_state &= ~PIPE_WANTR; 962 wakeup(wpipe); 963 } 964 error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH, 965 "pipbww", 0); 966 if (wpipe->pipe_state & PIPE_EOF) 967 break; 968 if (error) 969 break; 970 } 971 if (wpipe->pipe_state & PIPE_EOF) { 972 error = EPIPE; 973 break; 974 } 975 976 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 977 978 /* Writes of size <= PIPE_BUF must be atomic. */ 979 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 980 space = 0; 981 982 if (space > 0 && (wpipe->pipe_buffer.cnt < PIPE_SIZE)) { 983 if ((error = pipelock(wpipe,1)) == 0) { 984 int size; /* Transfer size */ 985 int segsize; /* first segment to transfer */ 986 987 /* 988 * It is possible for a direct write to 989 * slip in on us... handle it here... 990 */ 991 if (wpipe->pipe_state & PIPE_DIRECTW) { 992 pipeunlock(wpipe); 993 goto retrywrite; 994 } 995 /* 996 * If a process blocked in uiomove, our 997 * value for space might be bad. 998 * 999 * XXX will we be ok if the reader has gone 1000 * away here? 1001 */ 1002 if (space > wpipe->pipe_buffer.size - 1003 wpipe->pipe_buffer.cnt) { 1004 pipeunlock(wpipe); 1005 goto retrywrite; 1006 } 1007 1008 /* 1009 * Transfer size is minimum of uio transfer 1010 * and free space in pipe buffer. 1011 */ 1012 if (space > uio->uio_resid) 1013 size = uio->uio_resid; 1014 else 1015 size = space; 1016 /* 1017 * First segment to transfer is minimum of 1018 * transfer size and contiguous space in 1019 * pipe buffer. If first segment to transfer 1020 * is less than the transfer size, we've got 1021 * a wraparound in the buffer. 1022 */ 1023 segsize = wpipe->pipe_buffer.size - 1024 wpipe->pipe_buffer.in; 1025 if (segsize > size) 1026 segsize = size; 1027 1028 /* Transfer first segment */ 1029 1030 PIPE_UNLOCK(rpipe); 1031 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1032 segsize, uio); 1033 PIPE_LOCK(rpipe); 1034 1035 if (error == 0 && segsize < size) { 1036 /* 1037 * Transfer remaining part now, to 1038 * support atomic writes. Wraparound 1039 * happened. 1040 */ 1041 if (wpipe->pipe_buffer.in + segsize != 1042 wpipe->pipe_buffer.size) 1043 panic("Expected pipe buffer wraparound disappeared"); 1044 1045 PIPE_UNLOCK(rpipe); 1046 error = uiomove(&wpipe->pipe_buffer.buffer[0], 1047 size - segsize, uio); 1048 PIPE_LOCK(rpipe); 1049 } 1050 if (error == 0) { 1051 wpipe->pipe_buffer.in += size; 1052 if (wpipe->pipe_buffer.in >= 1053 wpipe->pipe_buffer.size) { 1054 if (wpipe->pipe_buffer.in != size - segsize + wpipe->pipe_buffer.size) 1055 panic("Expected wraparound bad"); 1056 wpipe->pipe_buffer.in = size - segsize; 1057 } 1058 1059 wpipe->pipe_buffer.cnt += size; 1060 if (wpipe->pipe_buffer.cnt > wpipe->pipe_buffer.size) 1061 panic("Pipe buffer overflow"); 1062 1063 } 1064 pipeunlock(wpipe); 1065 } 1066 if (error) 1067 break; 1068 1069 } else { 1070 /* 1071 * If the "read-side" has been blocked, wake it up now. 1072 */ 1073 if (wpipe->pipe_state & PIPE_WANTR) { 1074 wpipe->pipe_state &= ~PIPE_WANTR; 1075 wakeup(wpipe); 1076 } 1077 1078 /* 1079 * don't block on non-blocking I/O 1080 */ 1081 if (fp->f_flag & FNONBLOCK) { 1082 error = EAGAIN; 1083 break; 1084 } 1085 1086 /* 1087 * We have no more space and have something to offer, 1088 * wake up select/poll. 1089 */ 1090 pipeselwakeup(wpipe); 1091 1092 wpipe->pipe_state |= PIPE_WANTW; 1093 error = msleep(wpipe, PIPE_MTX(rpipe), 1094 PRIBIO | PCATCH, "pipewr", 0); 1095 if (error != 0) 1096 break; 1097 /* 1098 * If read side wants to go away, we just issue a signal 1099 * to ourselves. 1100 */ 1101 if (wpipe->pipe_state & PIPE_EOF) { 1102 error = EPIPE; 1103 break; 1104 } 1105 } 1106 } 1107 1108 --wpipe->pipe_busy; 1109 1110 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1111 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1112 wakeup(wpipe); 1113 } else if (wpipe->pipe_buffer.cnt > 0) { 1114 /* 1115 * If we have put any characters in the buffer, we wake up 1116 * the reader. 1117 */ 1118 if (wpipe->pipe_state & PIPE_WANTR) { 1119 wpipe->pipe_state &= ~PIPE_WANTR; 1120 wakeup(wpipe); 1121 } 1122 } 1123 1124 /* 1125 * Don't return EPIPE if I/O was successful 1126 */ 1127 if ((wpipe->pipe_buffer.cnt == 0) && 1128 (uio->uio_resid == 0) && 1129 (error == EPIPE)) { 1130 error = 0; 1131 } 1132 1133 if (error == 0) 1134 vfs_timestamp(&wpipe->pipe_mtime); 1135 1136 /* 1137 * We have something to offer, 1138 * wake up select/poll. 1139 */ 1140 if (wpipe->pipe_buffer.cnt) 1141 pipeselwakeup(wpipe); 1142 1143 PIPE_UNLOCK(rpipe); 1144 return (error); 1145 } 1146 1147 /* 1148 * we implement a very minimal set of ioctls for compatibility with sockets. 1149 */ 1150 static int 1151 pipe_ioctl(fp, cmd, data, active_cred, td) 1152 struct file *fp; 1153 u_long cmd; 1154 void *data; 1155 struct ucred *active_cred; 1156 struct thread *td; 1157 { 1158 struct pipe *mpipe = fp->f_data; 1159 #ifdef MAC 1160 int error; 1161 #endif 1162 1163 PIPE_LOCK(mpipe); 1164 1165 #ifdef MAC 1166 error = mac_check_pipe_ioctl(active_cred, mpipe, cmd, data); 1167 if (error) 1168 return (error); 1169 #endif 1170 1171 switch (cmd) { 1172 1173 case FIONBIO: 1174 PIPE_UNLOCK(mpipe); 1175 return (0); 1176 1177 case FIOASYNC: 1178 if (*(int *)data) { 1179 mpipe->pipe_state |= PIPE_ASYNC; 1180 } else { 1181 mpipe->pipe_state &= ~PIPE_ASYNC; 1182 } 1183 PIPE_UNLOCK(mpipe); 1184 return (0); 1185 1186 case FIONREAD: 1187 if (mpipe->pipe_state & PIPE_DIRECTW) 1188 *(int *)data = mpipe->pipe_map.cnt; 1189 else 1190 *(int *)data = mpipe->pipe_buffer.cnt; 1191 PIPE_UNLOCK(mpipe); 1192 return (0); 1193 1194 case FIOSETOWN: 1195 PIPE_UNLOCK(mpipe); 1196 return (fsetown(*(int *)data, &mpipe->pipe_sigio)); 1197 1198 case FIOGETOWN: 1199 PIPE_UNLOCK(mpipe); 1200 *(int *)data = fgetown(&mpipe->pipe_sigio); 1201 return (0); 1202 1203 /* This is deprecated, FIOSETOWN should be used instead. */ 1204 case TIOCSPGRP: 1205 PIPE_UNLOCK(mpipe); 1206 return (fsetown(-(*(int *)data), &mpipe->pipe_sigio)); 1207 1208 /* This is deprecated, FIOGETOWN should be used instead. */ 1209 case TIOCGPGRP: 1210 PIPE_UNLOCK(mpipe); 1211 *(int *)data = -fgetown(&mpipe->pipe_sigio); 1212 return (0); 1213 1214 } 1215 PIPE_UNLOCK(mpipe); 1216 return (ENOTTY); 1217 } 1218 1219 static int 1220 pipe_poll(fp, events, active_cred, td) 1221 struct file *fp; 1222 int events; 1223 struct ucred *active_cred; 1224 struct thread *td; 1225 { 1226 struct pipe *rpipe = fp->f_data; 1227 struct pipe *wpipe; 1228 int revents = 0; 1229 #ifdef MAC 1230 int error; 1231 #endif 1232 1233 wpipe = rpipe->pipe_peer; 1234 PIPE_LOCK(rpipe); 1235 #ifdef MAC 1236 error = mac_check_pipe_poll(active_cred, rpipe); 1237 if (error) 1238 goto locked_error; 1239 #endif 1240 if (events & (POLLIN | POLLRDNORM)) 1241 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1242 (rpipe->pipe_buffer.cnt > 0) || 1243 (rpipe->pipe_state & PIPE_EOF)) 1244 revents |= events & (POLLIN | POLLRDNORM); 1245 1246 if (events & (POLLOUT | POLLWRNORM)) 1247 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) || 1248 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1249 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1250 revents |= events & (POLLOUT | POLLWRNORM); 1251 1252 if ((rpipe->pipe_state & PIPE_EOF) || 1253 (wpipe == NULL) || 1254 (wpipe->pipe_state & PIPE_EOF)) 1255 revents |= POLLHUP; 1256 1257 if (revents == 0) { 1258 if (events & (POLLIN | POLLRDNORM)) { 1259 selrecord(td, &rpipe->pipe_sel); 1260 rpipe->pipe_state |= PIPE_SEL; 1261 } 1262 1263 if (events & (POLLOUT | POLLWRNORM)) { 1264 selrecord(td, &wpipe->pipe_sel); 1265 wpipe->pipe_state |= PIPE_SEL; 1266 } 1267 } 1268 #ifdef MAC 1269 locked_error: 1270 #endif 1271 PIPE_UNLOCK(rpipe); 1272 1273 return (revents); 1274 } 1275 1276 /* 1277 * We shouldn't need locks here as we're doing a read and this should 1278 * be a natural race. 1279 */ 1280 static int 1281 pipe_stat(fp, ub, active_cred, td) 1282 struct file *fp; 1283 struct stat *ub; 1284 struct ucred *active_cred; 1285 struct thread *td; 1286 { 1287 struct pipe *pipe = fp->f_data; 1288 #ifdef MAC 1289 int error; 1290 1291 PIPE_LOCK(pipe); 1292 error = mac_check_pipe_stat(active_cred, pipe); 1293 PIPE_UNLOCK(pipe); 1294 if (error) 1295 return (error); 1296 #endif 1297 bzero(ub, sizeof(*ub)); 1298 ub->st_mode = S_IFIFO; 1299 ub->st_blksize = pipe->pipe_buffer.size; 1300 ub->st_size = pipe->pipe_buffer.cnt; 1301 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1302 ub->st_atimespec = pipe->pipe_atime; 1303 ub->st_mtimespec = pipe->pipe_mtime; 1304 ub->st_ctimespec = pipe->pipe_ctime; 1305 ub->st_uid = fp->f_cred->cr_uid; 1306 ub->st_gid = fp->f_cred->cr_gid; 1307 /* 1308 * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen. 1309 * XXX (st_dev, st_ino) should be unique. 1310 */ 1311 return (0); 1312 } 1313 1314 /* ARGSUSED */ 1315 static int 1316 pipe_close(fp, td) 1317 struct file *fp; 1318 struct thread *td; 1319 { 1320 struct pipe *cpipe = fp->f_data; 1321 1322 fp->f_ops = &badfileops; 1323 fp->f_data = NULL; 1324 funsetown(&cpipe->pipe_sigio); 1325 pipeclose(cpipe); 1326 return (0); 1327 } 1328 1329 static void 1330 pipe_free_kmem(cpipe) 1331 struct pipe *cpipe; 1332 { 1333 1334 GIANT_REQUIRED; 1335 KASSERT(cpipe->pipe_mtxp == NULL || !mtx_owned(PIPE_MTX(cpipe)), 1336 ("pipespace: pipe mutex locked")); 1337 1338 if (cpipe->pipe_buffer.buffer != NULL) { 1339 if (cpipe->pipe_buffer.size > PIPE_SIZE) 1340 --nbigpipe; 1341 amountpipekva -= cpipe->pipe_buffer.size; 1342 kmem_free(kernel_map, 1343 (vm_offset_t)cpipe->pipe_buffer.buffer, 1344 cpipe->pipe_buffer.size); 1345 cpipe->pipe_buffer.buffer = NULL; 1346 } 1347 #ifndef PIPE_NODIRECT 1348 if (cpipe->pipe_map.kva != 0) { 1349 amountpipekva -= cpipe->pipe_buffer.size + PAGE_SIZE; 1350 kmem_free(kernel_map, 1351 cpipe->pipe_map.kva, 1352 cpipe->pipe_buffer.size + PAGE_SIZE); 1353 cpipe->pipe_map.cnt = 0; 1354 cpipe->pipe_map.kva = 0; 1355 cpipe->pipe_map.pos = 0; 1356 cpipe->pipe_map.npages = 0; 1357 } 1358 #endif 1359 } 1360 1361 /* 1362 * shutdown the pipe 1363 */ 1364 static void 1365 pipeclose(cpipe) 1366 struct pipe *cpipe; 1367 { 1368 struct pipe *ppipe; 1369 int hadpeer; 1370 1371 if (cpipe == NULL) 1372 return; 1373 1374 hadpeer = 0; 1375 1376 /* partially created pipes won't have a valid mutex. */ 1377 if (PIPE_MTX(cpipe) != NULL) 1378 PIPE_LOCK(cpipe); 1379 1380 pipeselwakeup(cpipe); 1381 1382 /* 1383 * If the other side is blocked, wake it up saying that 1384 * we want to close it down. 1385 */ 1386 while (cpipe->pipe_busy) { 1387 wakeup(cpipe); 1388 cpipe->pipe_state |= PIPE_WANT | PIPE_EOF; 1389 msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0); 1390 } 1391 1392 #ifdef MAC 1393 if (cpipe->pipe_label != NULL && cpipe->pipe_peer == NULL) 1394 mac_destroy_pipe(cpipe); 1395 #endif 1396 1397 /* 1398 * Disconnect from peer 1399 */ 1400 if ((ppipe = cpipe->pipe_peer) != NULL) { 1401 hadpeer++; 1402 pipeselwakeup(ppipe); 1403 1404 ppipe->pipe_state |= PIPE_EOF; 1405 wakeup(ppipe); 1406 KNOTE(&ppipe->pipe_sel.si_note, 0); 1407 ppipe->pipe_peer = NULL; 1408 } 1409 /* 1410 * free resources 1411 */ 1412 if (PIPE_MTX(cpipe) != NULL) { 1413 PIPE_UNLOCK(cpipe); 1414 if (!hadpeer) { 1415 mtx_destroy(PIPE_MTX(cpipe)); 1416 free(PIPE_MTX(cpipe), M_TEMP); 1417 } 1418 } 1419 mtx_lock(&Giant); 1420 pipe_free_kmem(cpipe); 1421 uma_zfree(pipe_zone, cpipe); 1422 mtx_unlock(&Giant); 1423 } 1424 1425 /*ARGSUSED*/ 1426 static int 1427 pipe_kqfilter(struct file *fp, struct knote *kn) 1428 { 1429 struct pipe *cpipe; 1430 1431 cpipe = kn->kn_fp->f_data; 1432 switch (kn->kn_filter) { 1433 case EVFILT_READ: 1434 kn->kn_fop = &pipe_rfiltops; 1435 break; 1436 case EVFILT_WRITE: 1437 kn->kn_fop = &pipe_wfiltops; 1438 cpipe = cpipe->pipe_peer; 1439 if (cpipe == NULL) 1440 /* other end of pipe has been closed */ 1441 return (EBADF); 1442 break; 1443 default: 1444 return (1); 1445 } 1446 kn->kn_hook = cpipe; 1447 1448 PIPE_LOCK(cpipe); 1449 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext); 1450 PIPE_UNLOCK(cpipe); 1451 return (0); 1452 } 1453 1454 static void 1455 filt_pipedetach(struct knote *kn) 1456 { 1457 struct pipe *cpipe = (struct pipe *)kn->kn_hook; 1458 1459 PIPE_LOCK(cpipe); 1460 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext); 1461 PIPE_UNLOCK(cpipe); 1462 } 1463 1464 /*ARGSUSED*/ 1465 static int 1466 filt_piperead(struct knote *kn, long hint) 1467 { 1468 struct pipe *rpipe = kn->kn_fp->f_data; 1469 struct pipe *wpipe = rpipe->pipe_peer; 1470 1471 PIPE_LOCK(rpipe); 1472 kn->kn_data = rpipe->pipe_buffer.cnt; 1473 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1474 kn->kn_data = rpipe->pipe_map.cnt; 1475 1476 if ((rpipe->pipe_state & PIPE_EOF) || 1477 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1478 kn->kn_flags |= EV_EOF; 1479 PIPE_UNLOCK(rpipe); 1480 return (1); 1481 } 1482 PIPE_UNLOCK(rpipe); 1483 return (kn->kn_data > 0); 1484 } 1485 1486 /*ARGSUSED*/ 1487 static int 1488 filt_pipewrite(struct knote *kn, long hint) 1489 { 1490 struct pipe *rpipe = kn->kn_fp->f_data; 1491 struct pipe *wpipe = rpipe->pipe_peer; 1492 1493 PIPE_LOCK(rpipe); 1494 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1495 kn->kn_data = 0; 1496 kn->kn_flags |= EV_EOF; 1497 PIPE_UNLOCK(rpipe); 1498 return (1); 1499 } 1500 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1501 if (wpipe->pipe_state & PIPE_DIRECTW) 1502 kn->kn_data = 0; 1503 1504 PIPE_UNLOCK(rpipe); 1505 return (kn->kn_data >= PIPE_BUF); 1506 } 1507