sys_pipe.c revision 116127
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: head/sys/kern/sys_pipe.c 116127 2003-06-09 21:57:48Z mux $ 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 */ 97static fo_rdwr_t pipe_read; 98static fo_rdwr_t pipe_write; 99static fo_ioctl_t pipe_ioctl; 100static fo_poll_t pipe_poll; 101static fo_kqfilter_t pipe_kqfilter; 102static fo_stat_t pipe_stat; 103static fo_close_t pipe_close; 104 105static struct fileops pipeops = { 106 pipe_read, pipe_write, pipe_ioctl, pipe_poll, pipe_kqfilter, 107 pipe_stat, pipe_close, DFLAG_PASSABLE 108}; 109 110static void filt_pipedetach(struct knote *kn); 111static int filt_piperead(struct knote *kn, long hint); 112static int filt_pipewrite(struct knote *kn, long hint); 113 114static struct filterops pipe_rfiltops = 115 { 1, NULL, filt_pipedetach, filt_piperead }; 116static 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 159static int nbigpipe; 160 161static int amountpipekva; 162 163static void pipeinit(void *dummy __unused); 164static void pipeclose(struct pipe *cpipe); 165static void pipe_free_kmem(struct pipe *cpipe); 166static int pipe_create(struct pipe **cpipep); 167static __inline int pipelock(struct pipe *cpipe, int catch); 168static __inline void pipeunlock(struct pipe *cpipe); 169static __inline void pipeselwakeup(struct pipe *cpipe); 170#ifndef PIPE_NODIRECT 171static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio); 172static void pipe_destroy_write_buffer(struct pipe *wpipe); 173static int pipe_direct_write(struct pipe *wpipe, struct uio *uio); 174static void pipe_clone_write_buffer(struct pipe *wpipe); 175#endif 176static int pipespace(struct pipe *cpipe, int size); 177 178static uma_zone_t pipe_zone; 179 180SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL); 181 182static void 183pipeinit(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 */ 194int 195pipe(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_WAITOK | 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 */ 291static int 292pipespace(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 atomic_add_int(&amountpipekva, cpipe->pipe_buffer.size); 336 return (0); 337} 338 339/* 340 * initialize and allocate VM and memory for pipe 341 */ 342static int 343pipe_create(cpipep) 344 struct pipe **cpipep; 345{ 346 struct pipe *cpipe; 347 int error; 348 349 *cpipep = uma_zalloc(pipe_zone, M_WAITOK); 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 */ 396static __inline int 397pipelock(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 */ 419static __inline void 420pipeunlock(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 432static __inline void 433pipeselwakeup(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 */ 447static int 448pipe_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( 485 &rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 486 size, uio); 487 PIPE_LOCK(rpipe); 488 if (error) 489 break; 490 491 rpipe->pipe_buffer.out += size; 492 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 493 rpipe->pipe_buffer.out = 0; 494 495 rpipe->pipe_buffer.cnt -= size; 496 497 /* 498 * If there is no more to read in the pipe, reset 499 * its pointers to the beginning. This improves 500 * cache hit stats. 501 */ 502 if (rpipe->pipe_buffer.cnt == 0) { 503 rpipe->pipe_buffer.in = 0; 504 rpipe->pipe_buffer.out = 0; 505 } 506 nread += size; 507#ifndef PIPE_NODIRECT 508 /* 509 * Direct copy, bypassing a kernel buffer. 510 */ 511 } else if ((size = rpipe->pipe_map.cnt) && 512 (rpipe->pipe_state & PIPE_DIRECTW)) { 513 caddr_t va; 514 if (size > (u_int) uio->uio_resid) 515 size = (u_int) uio->uio_resid; 516 517 va = (caddr_t) rpipe->pipe_map.kva + 518 rpipe->pipe_map.pos; 519 PIPE_UNLOCK(rpipe); 520 error = uiomove(va, size, uio); 521 PIPE_LOCK(rpipe); 522 if (error) 523 break; 524 nread += size; 525 rpipe->pipe_map.pos += size; 526 rpipe->pipe_map.cnt -= size; 527 if (rpipe->pipe_map.cnt == 0) { 528 rpipe->pipe_state &= ~PIPE_DIRECTW; 529 wakeup(rpipe); 530 } 531#endif 532 } else { 533 /* 534 * detect EOF condition 535 * read returns 0 on EOF, no need to set error 536 */ 537 if (rpipe->pipe_state & PIPE_EOF) 538 break; 539 540 /* 541 * If the "write-side" has been blocked, wake it up now. 542 */ 543 if (rpipe->pipe_state & PIPE_WANTW) { 544 rpipe->pipe_state &= ~PIPE_WANTW; 545 wakeup(rpipe); 546 } 547 548 /* 549 * Break if some data was read. 550 */ 551 if (nread > 0) 552 break; 553 554 /* 555 * Unlock the pipe buffer for our remaining processing. 556 * We will either break out with an error or we will 557 * sleep and relock to loop. 558 */ 559 pipeunlock(rpipe); 560 561 /* 562 * Handle non-blocking mode operation or 563 * wait for more data. 564 */ 565 if (fp->f_flag & FNONBLOCK) { 566 error = EAGAIN; 567 } else { 568 rpipe->pipe_state |= PIPE_WANTR; 569 if ((error = msleep(rpipe, PIPE_MTX(rpipe), 570 PRIBIO | PCATCH, 571 "piperd", 0)) == 0) 572 error = pipelock(rpipe, 1); 573 } 574 if (error) 575 goto unlocked_error; 576 } 577 } 578#ifdef MAC 579locked_error: 580#endif 581 pipeunlock(rpipe); 582 583 /* XXX: should probably do this before getting any locks. */ 584 if (error == 0) 585 vfs_timestamp(&rpipe->pipe_atime); 586unlocked_error: 587 --rpipe->pipe_busy; 588 589 /* 590 * PIPE_WANT processing only makes sense if pipe_busy is 0. 591 */ 592 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 593 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 594 wakeup(rpipe); 595 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 596 /* 597 * Handle write blocking hysteresis. 598 */ 599 if (rpipe->pipe_state & PIPE_WANTW) { 600 rpipe->pipe_state &= ~PIPE_WANTW; 601 wakeup(rpipe); 602 } 603 } 604 605 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 606 pipeselwakeup(rpipe); 607 608 PIPE_UNLOCK(rpipe); 609 return (error); 610} 611 612#ifndef PIPE_NODIRECT 613/* 614 * Map the sending processes' buffer into kernel space and wire it. 615 * This is similar to a physical write operation. 616 */ 617static int 618pipe_build_write_buffer(wpipe, uio) 619 struct pipe *wpipe; 620 struct uio *uio; 621{ 622 u_int size; 623 int i; 624 vm_offset_t addr, endaddr; 625 vm_paddr_t paddr; 626 627 GIANT_REQUIRED; 628 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 629 630 size = (u_int) uio->uio_iov->iov_len; 631 if (size > wpipe->pipe_buffer.size) 632 size = wpipe->pipe_buffer.size; 633 634 endaddr = round_page((vm_offset_t)uio->uio_iov->iov_base + size); 635 addr = trunc_page((vm_offset_t)uio->uio_iov->iov_base); 636 for (i = 0; addr < endaddr; addr += PAGE_SIZE, i++) { 637 vm_page_t m; 638 639 /* 640 * vm_fault_quick() can sleep. Consequently, 641 * vm_page_lock_queue() and vm_page_unlock_queue() 642 * should not be performed outside of this loop. 643 */ 644 if (vm_fault_quick((caddr_t)addr, VM_PROT_READ) < 0 || 645 (paddr = pmap_extract(vmspace_pmap(curproc->p_vmspace), 646 addr)) == 0) { 647 int j; 648 649 vm_page_lock_queues(); 650 for (j = 0; j < i; j++) 651 vm_page_unwire(wpipe->pipe_map.ms[j], 1); 652 vm_page_unlock_queues(); 653 return (EFAULT); 654 } 655 656 m = PHYS_TO_VM_PAGE(paddr); 657 vm_page_lock_queues(); 658 vm_page_wire(m); 659 vm_page_unlock_queues(); 660 wpipe->pipe_map.ms[i] = m; 661 } 662 663/* 664 * set up the control block 665 */ 666 wpipe->pipe_map.npages = i; 667 wpipe->pipe_map.pos = 668 ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; 669 wpipe->pipe_map.cnt = size; 670 671/* 672 * and map the buffer 673 */ 674 if (wpipe->pipe_map.kva == 0) { 675 /* 676 * We need to allocate space for an extra page because the 677 * address range might (will) span pages at times. 678 */ 679 wpipe->pipe_map.kva = kmem_alloc_pageable(kernel_map, 680 wpipe->pipe_buffer.size + PAGE_SIZE); 681 atomic_add_int(&amountpipekva, 682 wpipe->pipe_buffer.size + PAGE_SIZE); 683 } 684 pmap_qenter(wpipe->pipe_map.kva, wpipe->pipe_map.ms, 685 wpipe->pipe_map.npages); 686 687/* 688 * and update the uio data 689 */ 690 691 uio->uio_iov->iov_len -= size; 692 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; 693 if (uio->uio_iov->iov_len == 0) 694 uio->uio_iov++; 695 uio->uio_resid -= size; 696 uio->uio_offset += size; 697 return (0); 698} 699 700/* 701 * unmap and unwire the process buffer 702 */ 703static void 704pipe_destroy_write_buffer(wpipe) 705 struct pipe *wpipe; 706{ 707 int i; 708 709 GIANT_REQUIRED; 710 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 711 712 if (wpipe->pipe_map.kva) { 713 pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages); 714 715 if (amountpipekva > MAXPIPEKVA) { 716 vm_offset_t kva = wpipe->pipe_map.kva; 717 wpipe->pipe_map.kva = 0; 718 kmem_free(kernel_map, kva, 719 wpipe->pipe_buffer.size + PAGE_SIZE); 720 atomic_subtract_int(&amountpipekva, 721 wpipe->pipe_buffer.size + PAGE_SIZE); 722 } 723 } 724 vm_page_lock_queues(); 725 for (i = 0; i < wpipe->pipe_map.npages; i++) 726 vm_page_unwire(wpipe->pipe_map.ms[i], 1); 727 vm_page_unlock_queues(); 728 wpipe->pipe_map.npages = 0; 729} 730 731/* 732 * In the case of a signal, the writing process might go away. This 733 * code copies the data into the circular buffer so that the source 734 * pages can be freed without loss of data. 735 */ 736static void 737pipe_clone_write_buffer(wpipe) 738 struct pipe *wpipe; 739{ 740 int size; 741 int pos; 742 743 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 744 size = wpipe->pipe_map.cnt; 745 pos = wpipe->pipe_map.pos; 746 747 wpipe->pipe_buffer.in = size; 748 wpipe->pipe_buffer.out = 0; 749 wpipe->pipe_buffer.cnt = size; 750 wpipe->pipe_state &= ~PIPE_DIRECTW; 751 752 PIPE_GET_GIANT(wpipe); 753 bcopy((caddr_t) wpipe->pipe_map.kva + pos, 754 wpipe->pipe_buffer.buffer, size); 755 pipe_destroy_write_buffer(wpipe); 756 PIPE_DROP_GIANT(wpipe); 757} 758 759/* 760 * This implements the pipe buffer write mechanism. Note that only 761 * a direct write OR a normal pipe write can be pending at any given time. 762 * If there are any characters in the pipe buffer, the direct write will 763 * be deferred until the receiving process grabs all of the bytes from 764 * the pipe buffer. Then the direct mapping write is set-up. 765 */ 766static int 767pipe_direct_write(wpipe, uio) 768 struct pipe *wpipe; 769 struct uio *uio; 770{ 771 int error; 772 773retry: 774 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 775 while (wpipe->pipe_state & PIPE_DIRECTW) { 776 if (wpipe->pipe_state & PIPE_WANTR) { 777 wpipe->pipe_state &= ~PIPE_WANTR; 778 wakeup(wpipe); 779 } 780 wpipe->pipe_state |= PIPE_WANTW; 781 error = msleep(wpipe, PIPE_MTX(wpipe), 782 PRIBIO | PCATCH, "pipdww", 0); 783 if (error) 784 goto error1; 785 if (wpipe->pipe_state & PIPE_EOF) { 786 error = EPIPE; 787 goto error1; 788 } 789 } 790 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 791 if (wpipe->pipe_buffer.cnt > 0) { 792 if (wpipe->pipe_state & PIPE_WANTR) { 793 wpipe->pipe_state &= ~PIPE_WANTR; 794 wakeup(wpipe); 795 } 796 797 wpipe->pipe_state |= PIPE_WANTW; 798 error = msleep(wpipe, PIPE_MTX(wpipe), 799 PRIBIO | PCATCH, "pipdwc", 0); 800 if (error) 801 goto error1; 802 if (wpipe->pipe_state & PIPE_EOF) { 803 error = EPIPE; 804 goto error1; 805 } 806 goto retry; 807 } 808 809 wpipe->pipe_state |= PIPE_DIRECTW; 810 811 pipelock(wpipe, 0); 812 PIPE_GET_GIANT(wpipe); 813 error = pipe_build_write_buffer(wpipe, uio); 814 PIPE_DROP_GIANT(wpipe); 815 pipeunlock(wpipe); 816 if (error) { 817 wpipe->pipe_state &= ~PIPE_DIRECTW; 818 goto error1; 819 } 820 821 error = 0; 822 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 823 if (wpipe->pipe_state & PIPE_EOF) { 824 pipelock(wpipe, 0); 825 PIPE_GET_GIANT(wpipe); 826 pipe_destroy_write_buffer(wpipe); 827 PIPE_DROP_GIANT(wpipe); 828 pipeselwakeup(wpipe); 829 pipeunlock(wpipe); 830 error = EPIPE; 831 goto error1; 832 } 833 if (wpipe->pipe_state & PIPE_WANTR) { 834 wpipe->pipe_state &= ~PIPE_WANTR; 835 wakeup(wpipe); 836 } 837 pipeselwakeup(wpipe); 838 error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, 839 "pipdwt", 0); 840 } 841 842 pipelock(wpipe,0); 843 if (wpipe->pipe_state & PIPE_DIRECTW) { 844 /* 845 * this bit of trickery substitutes a kernel buffer for 846 * the process that might be going away. 847 */ 848 pipe_clone_write_buffer(wpipe); 849 } else { 850 PIPE_GET_GIANT(wpipe); 851 pipe_destroy_write_buffer(wpipe); 852 PIPE_DROP_GIANT(wpipe); 853 } 854 pipeunlock(wpipe); 855 return (error); 856 857error1: 858 wakeup(wpipe); 859 return (error); 860} 861#endif 862 863static int 864pipe_write(fp, uio, active_cred, flags, td) 865 struct file *fp; 866 struct uio *uio; 867 struct ucred *active_cred; 868 struct thread *td; 869 int flags; 870{ 871 int error = 0; 872 int orig_resid; 873 struct pipe *wpipe, *rpipe; 874 875 rpipe = fp->f_data; 876 wpipe = rpipe->pipe_peer; 877 878 PIPE_LOCK(rpipe); 879 /* 880 * detect loss of pipe read side, issue SIGPIPE if lost. 881 */ 882 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 883 PIPE_UNLOCK(rpipe); 884 return (EPIPE); 885 } 886#ifdef MAC 887 error = mac_check_pipe_write(active_cred, wpipe); 888 if (error) { 889 PIPE_UNLOCK(rpipe); 890 return (error); 891 } 892#endif 893 ++wpipe->pipe_busy; 894 895 /* 896 * If it is advantageous to resize the pipe buffer, do 897 * so. 898 */ 899 if ((uio->uio_resid > PIPE_SIZE) && 900 (nbigpipe < LIMITBIGPIPES) && 901 (wpipe->pipe_state & PIPE_DIRECTW) == 0 && 902 (wpipe->pipe_buffer.size <= PIPE_SIZE) && 903 (wpipe->pipe_buffer.cnt == 0)) { 904 905 if ((error = pipelock(wpipe, 1)) == 0) { 906 PIPE_GET_GIANT(wpipe); 907 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 908 nbigpipe++; 909 PIPE_DROP_GIANT(wpipe); 910 pipeunlock(wpipe); 911 } 912 } 913 914 /* 915 * If an early error occured unbusy and return, waking up any pending 916 * readers. 917 */ 918 if (error) { 919 --wpipe->pipe_busy; 920 if ((wpipe->pipe_busy == 0) && 921 (wpipe->pipe_state & PIPE_WANT)) { 922 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 923 wakeup(wpipe); 924 } 925 PIPE_UNLOCK(rpipe); 926 return(error); 927 } 928 929 orig_resid = uio->uio_resid; 930 931 while (uio->uio_resid) { 932 int space; 933 934#ifndef PIPE_NODIRECT 935 /* 936 * If the transfer is large, we can gain performance if 937 * we do process-to-process copies directly. 938 * If the write is non-blocking, we don't use the 939 * direct write mechanism. 940 * 941 * The direct write mechanism will detect the reader going 942 * away on us. 943 */ 944 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && 945 (fp->f_flag & FNONBLOCK) == 0 && 946 (wpipe->pipe_map.kva || (amountpipekva < LIMITPIPEKVA)) && 947 (uio->uio_iov->iov_len >= PIPE_MINDIRECT)) { 948 error = pipe_direct_write(wpipe, uio); 949 if (error) 950 break; 951 continue; 952 } 953#endif 954 955 /* 956 * Pipe buffered writes cannot be coincidental with 957 * direct writes. We wait until the currently executing 958 * direct write is completed before we start filling the 959 * pipe buffer. We break out if a signal occurs or the 960 * reader goes away. 961 */ 962 retrywrite: 963 while (wpipe->pipe_state & PIPE_DIRECTW) { 964 if (wpipe->pipe_state & PIPE_WANTR) { 965 wpipe->pipe_state &= ~PIPE_WANTR; 966 wakeup(wpipe); 967 } 968 error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH, 969 "pipbww", 0); 970 if (wpipe->pipe_state & PIPE_EOF) 971 break; 972 if (error) 973 break; 974 } 975 if (wpipe->pipe_state & PIPE_EOF) { 976 error = EPIPE; 977 break; 978 } 979 980 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 981 982 /* Writes of size <= PIPE_BUF must be atomic. */ 983 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 984 space = 0; 985 986 if (space > 0 && (wpipe->pipe_buffer.cnt < PIPE_SIZE)) { 987 if ((error = pipelock(wpipe,1)) == 0) { 988 int size; /* Transfer size */ 989 int segsize; /* first segment to transfer */ 990 991 /* 992 * It is possible for a direct write to 993 * slip in on us... handle it here... 994 */ 995 if (wpipe->pipe_state & PIPE_DIRECTW) { 996 pipeunlock(wpipe); 997 goto retrywrite; 998 } 999 /* 1000 * If a process blocked in uiomove, our 1001 * value for space might be bad. 1002 * 1003 * XXX will we be ok if the reader has gone 1004 * away here? 1005 */ 1006 if (space > wpipe->pipe_buffer.size - 1007 wpipe->pipe_buffer.cnt) { 1008 pipeunlock(wpipe); 1009 goto retrywrite; 1010 } 1011 1012 /* 1013 * Transfer size is minimum of uio transfer 1014 * and free space in pipe buffer. 1015 */ 1016 if (space > uio->uio_resid) 1017 size = uio->uio_resid; 1018 else 1019 size = space; 1020 /* 1021 * First segment to transfer is minimum of 1022 * transfer size and contiguous space in 1023 * pipe buffer. If first segment to transfer 1024 * is less than the transfer size, we've got 1025 * a wraparound in the buffer. 1026 */ 1027 segsize = wpipe->pipe_buffer.size - 1028 wpipe->pipe_buffer.in; 1029 if (segsize > size) 1030 segsize = size; 1031 1032 /* Transfer first segment */ 1033 1034 PIPE_UNLOCK(rpipe); 1035 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1036 segsize, uio); 1037 PIPE_LOCK(rpipe); 1038 1039 if (error == 0 && segsize < size) { 1040 /* 1041 * Transfer remaining part now, to 1042 * support atomic writes. Wraparound 1043 * happened. 1044 */ 1045 if (wpipe->pipe_buffer.in + segsize != 1046 wpipe->pipe_buffer.size) 1047 panic("Expected pipe buffer " 1048 "wraparound disappeared"); 1049 1050 PIPE_UNLOCK(rpipe); 1051 error = uiomove( 1052 &wpipe->pipe_buffer.buffer[0], 1053 size - segsize, uio); 1054 PIPE_LOCK(rpipe); 1055 } 1056 if (error == 0) { 1057 wpipe->pipe_buffer.in += size; 1058 if (wpipe->pipe_buffer.in >= 1059 wpipe->pipe_buffer.size) { 1060 if (wpipe->pipe_buffer.in != 1061 size - segsize + 1062 wpipe->pipe_buffer.size) 1063 panic("Expected " 1064 "wraparound bad"); 1065 wpipe->pipe_buffer.in = size - 1066 segsize; 1067 } 1068 1069 wpipe->pipe_buffer.cnt += size; 1070 if (wpipe->pipe_buffer.cnt > 1071 wpipe->pipe_buffer.size) 1072 panic("Pipe buffer overflow"); 1073 1074 } 1075 pipeunlock(wpipe); 1076 } 1077 if (error) 1078 break; 1079 1080 } else { 1081 /* 1082 * If the "read-side" has been blocked, wake it up now. 1083 */ 1084 if (wpipe->pipe_state & PIPE_WANTR) { 1085 wpipe->pipe_state &= ~PIPE_WANTR; 1086 wakeup(wpipe); 1087 } 1088 1089 /* 1090 * don't block on non-blocking I/O 1091 */ 1092 if (fp->f_flag & FNONBLOCK) { 1093 error = EAGAIN; 1094 break; 1095 } 1096 1097 /* 1098 * We have no more space and have something to offer, 1099 * wake up select/poll. 1100 */ 1101 pipeselwakeup(wpipe); 1102 1103 wpipe->pipe_state |= PIPE_WANTW; 1104 error = msleep(wpipe, PIPE_MTX(rpipe), 1105 PRIBIO | PCATCH, "pipewr", 0); 1106 if (error != 0) 1107 break; 1108 /* 1109 * If read side wants to go away, we just issue a signal 1110 * to ourselves. 1111 */ 1112 if (wpipe->pipe_state & PIPE_EOF) { 1113 error = EPIPE; 1114 break; 1115 } 1116 } 1117 } 1118 1119 --wpipe->pipe_busy; 1120 1121 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1122 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1123 wakeup(wpipe); 1124 } else if (wpipe->pipe_buffer.cnt > 0) { 1125 /* 1126 * If we have put any characters in the buffer, we wake up 1127 * the reader. 1128 */ 1129 if (wpipe->pipe_state & PIPE_WANTR) { 1130 wpipe->pipe_state &= ~PIPE_WANTR; 1131 wakeup(wpipe); 1132 } 1133 } 1134 1135 /* 1136 * Don't return EPIPE if I/O was successful 1137 */ 1138 if ((wpipe->pipe_buffer.cnt == 0) && 1139 (uio->uio_resid == 0) && 1140 (error == EPIPE)) { 1141 error = 0; 1142 } 1143 1144 if (error == 0) 1145 vfs_timestamp(&wpipe->pipe_mtime); 1146 1147 /* 1148 * We have something to offer, 1149 * wake up select/poll. 1150 */ 1151 if (wpipe->pipe_buffer.cnt) 1152 pipeselwakeup(wpipe); 1153 1154 PIPE_UNLOCK(rpipe); 1155 return (error); 1156} 1157 1158/* 1159 * we implement a very minimal set of ioctls for compatibility with sockets. 1160 */ 1161static int 1162pipe_ioctl(fp, cmd, data, active_cred, td) 1163 struct file *fp; 1164 u_long cmd; 1165 void *data; 1166 struct ucred *active_cred; 1167 struct thread *td; 1168{ 1169 struct pipe *mpipe = fp->f_data; 1170#ifdef MAC 1171 int error; 1172#endif 1173 1174 PIPE_LOCK(mpipe); 1175 1176#ifdef MAC 1177 error = mac_check_pipe_ioctl(active_cred, mpipe, cmd, data); 1178 if (error) 1179 return (error); 1180#endif 1181 1182 switch (cmd) { 1183 1184 case FIONBIO: 1185 PIPE_UNLOCK(mpipe); 1186 return (0); 1187 1188 case FIOASYNC: 1189 if (*(int *)data) { 1190 mpipe->pipe_state |= PIPE_ASYNC; 1191 } else { 1192 mpipe->pipe_state &= ~PIPE_ASYNC; 1193 } 1194 PIPE_UNLOCK(mpipe); 1195 return (0); 1196 1197 case FIONREAD: 1198 if (mpipe->pipe_state & PIPE_DIRECTW) 1199 *(int *)data = mpipe->pipe_map.cnt; 1200 else 1201 *(int *)data = mpipe->pipe_buffer.cnt; 1202 PIPE_UNLOCK(mpipe); 1203 return (0); 1204 1205 case FIOSETOWN: 1206 PIPE_UNLOCK(mpipe); 1207 return (fsetown(*(int *)data, &mpipe->pipe_sigio)); 1208 1209 case FIOGETOWN: 1210 PIPE_UNLOCK(mpipe); 1211 *(int *)data = fgetown(&mpipe->pipe_sigio); 1212 return (0); 1213 1214 /* This is deprecated, FIOSETOWN should be used instead. */ 1215 case TIOCSPGRP: 1216 PIPE_UNLOCK(mpipe); 1217 return (fsetown(-(*(int *)data), &mpipe->pipe_sigio)); 1218 1219 /* This is deprecated, FIOGETOWN should be used instead. */ 1220 case TIOCGPGRP: 1221 PIPE_UNLOCK(mpipe); 1222 *(int *)data = -fgetown(&mpipe->pipe_sigio); 1223 return (0); 1224 1225 } 1226 PIPE_UNLOCK(mpipe); 1227 return (ENOTTY); 1228} 1229 1230static int 1231pipe_poll(fp, events, active_cred, td) 1232 struct file *fp; 1233 int events; 1234 struct ucred *active_cred; 1235 struct thread *td; 1236{ 1237 struct pipe *rpipe = fp->f_data; 1238 struct pipe *wpipe; 1239 int revents = 0; 1240#ifdef MAC 1241 int error; 1242#endif 1243 1244 wpipe = rpipe->pipe_peer; 1245 PIPE_LOCK(rpipe); 1246#ifdef MAC 1247 error = mac_check_pipe_poll(active_cred, rpipe); 1248 if (error) 1249 goto locked_error; 1250#endif 1251 if (events & (POLLIN | POLLRDNORM)) 1252 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1253 (rpipe->pipe_buffer.cnt > 0) || 1254 (rpipe->pipe_state & PIPE_EOF)) 1255 revents |= events & (POLLIN | POLLRDNORM); 1256 1257 if (events & (POLLOUT | POLLWRNORM)) 1258 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) || 1259 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1260 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1261 revents |= events & (POLLOUT | POLLWRNORM); 1262 1263 if ((rpipe->pipe_state & PIPE_EOF) || 1264 (wpipe == NULL) || 1265 (wpipe->pipe_state & PIPE_EOF)) 1266 revents |= POLLHUP; 1267 1268 if (revents == 0) { 1269 if (events & (POLLIN | POLLRDNORM)) { 1270 selrecord(td, &rpipe->pipe_sel); 1271 rpipe->pipe_state |= PIPE_SEL; 1272 } 1273 1274 if (events & (POLLOUT | POLLWRNORM)) { 1275 selrecord(td, &wpipe->pipe_sel); 1276 wpipe->pipe_state |= PIPE_SEL; 1277 } 1278 } 1279#ifdef MAC 1280locked_error: 1281#endif 1282 PIPE_UNLOCK(rpipe); 1283 1284 return (revents); 1285} 1286 1287/* 1288 * We shouldn't need locks here as we're doing a read and this should 1289 * be a natural race. 1290 */ 1291static int 1292pipe_stat(fp, ub, active_cred, td) 1293 struct file *fp; 1294 struct stat *ub; 1295 struct ucred *active_cred; 1296 struct thread *td; 1297{ 1298 struct pipe *pipe = fp->f_data; 1299#ifdef MAC 1300 int error; 1301 1302 PIPE_LOCK(pipe); 1303 error = mac_check_pipe_stat(active_cred, pipe); 1304 PIPE_UNLOCK(pipe); 1305 if (error) 1306 return (error); 1307#endif 1308 bzero(ub, sizeof(*ub)); 1309 ub->st_mode = S_IFIFO; 1310 ub->st_blksize = pipe->pipe_buffer.size; 1311 ub->st_size = pipe->pipe_buffer.cnt; 1312 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1313 ub->st_atimespec = pipe->pipe_atime; 1314 ub->st_mtimespec = pipe->pipe_mtime; 1315 ub->st_ctimespec = pipe->pipe_ctime; 1316 ub->st_uid = fp->f_cred->cr_uid; 1317 ub->st_gid = fp->f_cred->cr_gid; 1318 /* 1319 * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen. 1320 * XXX (st_dev, st_ino) should be unique. 1321 */ 1322 return (0); 1323} 1324 1325/* ARGSUSED */ 1326static int 1327pipe_close(fp, td) 1328 struct file *fp; 1329 struct thread *td; 1330{ 1331 struct pipe *cpipe = fp->f_data; 1332 1333 fp->f_ops = &badfileops; 1334 fp->f_data = NULL; 1335 funsetown(&cpipe->pipe_sigio); 1336 pipeclose(cpipe); 1337 return (0); 1338} 1339 1340static void 1341pipe_free_kmem(cpipe) 1342 struct pipe *cpipe; 1343{ 1344 1345 GIANT_REQUIRED; 1346 KASSERT(cpipe->pipe_mtxp == NULL || !mtx_owned(PIPE_MTX(cpipe)), 1347 ("pipespace: pipe mutex locked")); 1348 1349 if (cpipe->pipe_buffer.buffer != NULL) { 1350 if (cpipe->pipe_buffer.size > PIPE_SIZE) 1351 --nbigpipe; 1352 atomic_subtract_int(&amountpipekva, cpipe->pipe_buffer.size); 1353 kmem_free(kernel_map, 1354 (vm_offset_t)cpipe->pipe_buffer.buffer, 1355 cpipe->pipe_buffer.size); 1356 cpipe->pipe_buffer.buffer = NULL; 1357 } 1358#ifndef PIPE_NODIRECT 1359 if (cpipe->pipe_map.kva != 0) { 1360 atomic_subtract_int(&amountpipekva, 1361 cpipe->pipe_buffer.size + PAGE_SIZE); 1362 kmem_free(kernel_map, 1363 cpipe->pipe_map.kva, 1364 cpipe->pipe_buffer.size + PAGE_SIZE); 1365 cpipe->pipe_map.cnt = 0; 1366 cpipe->pipe_map.kva = 0; 1367 cpipe->pipe_map.pos = 0; 1368 cpipe->pipe_map.npages = 0; 1369 } 1370#endif 1371} 1372 1373/* 1374 * shutdown the pipe 1375 */ 1376static void 1377pipeclose(cpipe) 1378 struct pipe *cpipe; 1379{ 1380 struct pipe *ppipe; 1381 int hadpeer; 1382 1383 if (cpipe == NULL) 1384 return; 1385 1386 hadpeer = 0; 1387 1388 /* partially created pipes won't have a valid mutex. */ 1389 if (PIPE_MTX(cpipe) != NULL) 1390 PIPE_LOCK(cpipe); 1391 1392 pipeselwakeup(cpipe); 1393 1394 /* 1395 * If the other side is blocked, wake it up saying that 1396 * we want to close it down. 1397 */ 1398 while (cpipe->pipe_busy) { 1399 wakeup(cpipe); 1400 cpipe->pipe_state |= PIPE_WANT | PIPE_EOF; 1401 msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0); 1402 } 1403 1404#ifdef MAC 1405 if (cpipe->pipe_label != NULL && cpipe->pipe_peer == NULL) 1406 mac_destroy_pipe(cpipe); 1407#endif 1408 1409 /* 1410 * Disconnect from peer 1411 */ 1412 if ((ppipe = cpipe->pipe_peer) != NULL) { 1413 hadpeer++; 1414 pipeselwakeup(ppipe); 1415 1416 ppipe->pipe_state |= PIPE_EOF; 1417 wakeup(ppipe); 1418 KNOTE(&ppipe->pipe_sel.si_note, 0); 1419 ppipe->pipe_peer = NULL; 1420 } 1421 /* 1422 * free resources 1423 */ 1424 if (PIPE_MTX(cpipe) != NULL) { 1425 PIPE_UNLOCK(cpipe); 1426 if (!hadpeer) { 1427 mtx_destroy(PIPE_MTX(cpipe)); 1428 free(PIPE_MTX(cpipe), M_TEMP); 1429 } 1430 } 1431 mtx_lock(&Giant); 1432 pipe_free_kmem(cpipe); 1433 uma_zfree(pipe_zone, cpipe); 1434 mtx_unlock(&Giant); 1435} 1436 1437/*ARGSUSED*/ 1438static int 1439pipe_kqfilter(struct file *fp, struct knote *kn) 1440{ 1441 struct pipe *cpipe; 1442 1443 cpipe = kn->kn_fp->f_data; 1444 switch (kn->kn_filter) { 1445 case EVFILT_READ: 1446 kn->kn_fop = &pipe_rfiltops; 1447 break; 1448 case EVFILT_WRITE: 1449 kn->kn_fop = &pipe_wfiltops; 1450 cpipe = cpipe->pipe_peer; 1451 if (cpipe == NULL) 1452 /* other end of pipe has been closed */ 1453 return (EBADF); 1454 break; 1455 default: 1456 return (1); 1457 } 1458 kn->kn_hook = cpipe; 1459 1460 PIPE_LOCK(cpipe); 1461 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext); 1462 PIPE_UNLOCK(cpipe); 1463 return (0); 1464} 1465 1466static void 1467filt_pipedetach(struct knote *kn) 1468{ 1469 struct pipe *cpipe = (struct pipe *)kn->kn_hook; 1470 1471 PIPE_LOCK(cpipe); 1472 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext); 1473 PIPE_UNLOCK(cpipe); 1474} 1475 1476/*ARGSUSED*/ 1477static int 1478filt_piperead(struct knote *kn, long hint) 1479{ 1480 struct pipe *rpipe = kn->kn_fp->f_data; 1481 struct pipe *wpipe = rpipe->pipe_peer; 1482 1483 PIPE_LOCK(rpipe); 1484 kn->kn_data = rpipe->pipe_buffer.cnt; 1485 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1486 kn->kn_data = rpipe->pipe_map.cnt; 1487 1488 if ((rpipe->pipe_state & PIPE_EOF) || 1489 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1490 kn->kn_flags |= EV_EOF; 1491 PIPE_UNLOCK(rpipe); 1492 return (1); 1493 } 1494 PIPE_UNLOCK(rpipe); 1495 return (kn->kn_data > 0); 1496} 1497 1498/*ARGSUSED*/ 1499static int 1500filt_pipewrite(struct knote *kn, long hint) 1501{ 1502 struct pipe *rpipe = kn->kn_fp->f_data; 1503 struct pipe *wpipe = rpipe->pipe_peer; 1504 1505 PIPE_LOCK(rpipe); 1506 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1507 kn->kn_data = 0; 1508 kn->kn_flags |= EV_EOF; 1509 PIPE_UNLOCK(rpipe); 1510 return (1); 1511 } 1512 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1513 if (wpipe->pipe_state & PIPE_DIRECTW) 1514 kn->kn_data = 0; 1515 1516 PIPE_UNLOCK(rpipe); 1517 return (kn->kn_data >= PIPE_BUF); 1518} 1519