1 /* $NetBSD: sys_pipe.c,v 1.75 2006/09/23 15:36:12 xtraeme Exp $ */ 2 3 /*- 4 * Copyright (c) 2003 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Paul Kranenburg. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Copyright (c) 1996 John S. Dyson 41 * All rights reserved. 42 * 43 * Redistribution and use in source and binary forms, with or without 44 * modification, are permitted provided that the following conditions 45 * are met: 46 * 1. Redistributions of source code must retain the above copyright 47 * notice immediately at the beginning of the file, without modification, 48 * this list of conditions, and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. Absolutely no warranty of function or purpose is made by the author 53 * John S. Dyson. 54 * 4. Modifications may be freely made to this file if the above conditions 55 * are met. 56 * 57 * $FreeBSD: src/sys/kern/sys_pipe.c,v 1.95 2002/03/09 22:06:31 alfred Exp $ 58 */ 59 60 /* 61 * This file contains a high-performance replacement for the socket-based 62 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support 63 * all features of sockets, but does do everything that pipes normally 64 * do. 65 * 66 * Adaption for NetBSD UVM, including uvm_loan() based direct write, was 67 * written by Jaromir Dolecek. 68 */ 69 70 /* 71 * This code has two modes of operation, a small write mode and a large 72 * write mode. The small write mode acts like conventional pipes with 73 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the 74 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT 75 * and PIPE_SIZE in size it is mapped read-only into the kernel address space 76 * using the UVM page loan facility from where the receiving process can copy 77 * the data directly from the pages in the sending process. 78 * 79 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will 80 * happen for small transfers so that the system will not spend all of 81 * its time context switching. PIPE_SIZE is constrained by the 82 * amount of kernel virtual memory. 83 */ 84 85 #include <sys/cdefs.h> 86 __KERNEL_RCSID(0, "$NetBSD: sys_pipe.c,v 1.75 2006/09/23 15:36:12 xtraeme Exp $"); 87 88 #include <sys/param.h> 89 #include <sys/systm.h> 90 #include <sys/proc.h> 91 #include <sys/fcntl.h> 92 #include <sys/file.h> 93 #include <sys/filedesc.h> 94 #include <sys/filio.h> 95 #include <sys/kernel.h> 96 #include <sys/ttycom.h> 97 #include <sys/stat.h> 98 #include <sys/malloc.h> 99 #include <sys/poll.h> 100 #include <sys/signalvar.h> 101 #include <sys/vnode.h> 102 #include <sys/uio.h> 103 #include <sys/lock.h> 104 #include <sys/select.h> 105 #include <sys/mount.h> 106 #include <sys/sa.h> 107 #include <sys/syscallargs.h> 108 #include <uvm/uvm.h> 109 #include <sys/sysctl.h> 110 #include <sys/kernel.h> 111 #include <sys/kauth.h> 112 113 #include <sys/pipe.h> 114 115 /* 116 * Use this define if you want to disable *fancy* VM things. Expect an 117 * approx 30% decrease in transfer rate. 118 */ 119 /* #define PIPE_NODIRECT */ 120 121 /* 122 * interfaces to the outside world 123 */ 124 static int pipe_read(struct file *fp, off_t *offset, struct uio *uio, 125 kauth_cred_t cred, int flags); 126 static int pipe_write(struct file *fp, off_t *offset, struct uio *uio, 127 kauth_cred_t cred, int flags); 128 static int pipe_close(struct file *fp, struct lwp *l); 129 static int pipe_poll(struct file *fp, int events, struct lwp *l); 130 static int pipe_kqfilter(struct file *fp, struct knote *kn); 131 static int pipe_stat(struct file *fp, struct stat *sb, struct lwp *l); 132 static int pipe_ioctl(struct file *fp, u_long cmd, void *data, 133 struct lwp *l); 134 135 static const struct fileops pipeops = { 136 pipe_read, pipe_write, pipe_ioctl, fnullop_fcntl, pipe_poll, 137 pipe_stat, pipe_close, pipe_kqfilter 138 }; 139 140 /* 141 * Default pipe buffer size(s), this can be kind-of large now because pipe 142 * space is pageable. The pipe code will try to maintain locality of 143 * reference for performance reasons, so small amounts of outstanding I/O 144 * will not wipe the cache. 145 */ 146 #define MINPIPESIZE (PIPE_SIZE/3) 147 #define MAXPIPESIZE (2*PIPE_SIZE/3) 148 149 /* 150 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but 151 * is there so that on large systems, we don't exhaust it. 152 */ 153 #define MAXPIPEKVA (8*1024*1024) 154 static int maxpipekva = MAXPIPEKVA; 155 156 /* 157 * Limit for direct transfers, we cannot, of course limit 158 * the amount of kva for pipes in general though. 159 */ 160 #define LIMITPIPEKVA (16*1024*1024) 161 static int limitpipekva = LIMITPIPEKVA; 162 163 /* 164 * Limit the number of "big" pipes 165 */ 166 #define LIMITBIGPIPES 32 167 static int maxbigpipes = LIMITBIGPIPES; 168 static int nbigpipe = 0; 169 170 /* 171 * Amount of KVA consumed by pipe buffers. 172 */ 173 static int amountpipekva = 0; 174 175 MALLOC_DEFINE(M_PIPE, "pipe", "Pipe structures"); 176 177 static void pipeclose(struct file *fp, struct pipe *pipe); 178 static void pipe_free_kmem(struct pipe *pipe); 179 static int pipe_create(struct pipe **pipep, int allockva); 180 static int pipelock(struct pipe *pipe, int catch); 181 static inline void pipeunlock(struct pipe *pipe); 182 static void pipeselwakeup(struct pipe *pipe, struct pipe *sigp, int code); 183 #ifndef PIPE_NODIRECT 184 static int pipe_direct_write(struct file *fp, struct pipe *wpipe, 185 struct uio *uio); 186 #endif 187 static int pipespace(struct pipe *pipe, int size); 188 189 #ifndef PIPE_NODIRECT 190 static int pipe_loan_alloc(struct pipe *, int); 191 static void pipe_loan_free(struct pipe *); 192 #endif /* PIPE_NODIRECT */ 193 194 static POOL_INIT(pipe_pool, sizeof(struct pipe), 0, 0, 0, "pipepl", 195 &pool_allocator_nointr); 196 197 /* 198 * The pipe system call for the DTYPE_PIPE type of pipes 199 */ 200 201 /* ARGSUSED */ 202 int 203 sys_pipe(struct lwp *l, void *v, register_t *retval) 204 { 205 struct file *rf, *wf; 206 struct pipe *rpipe, *wpipe; 207 int fd, error; 208 209 rpipe = wpipe = NULL; 210 if (pipe_create(&rpipe, 1) || pipe_create(&wpipe, 0)) { 211 pipeclose(NULL, rpipe); 212 pipeclose(NULL, wpipe); 213 return (ENFILE); 214 } 215 216 /* 217 * Note: the file structure returned from falloc() is marked 218 * as 'larval' initially. Unless we mark it as 'mature' by 219 * FILE_SET_MATURE(), any attempt to do anything with it would 220 * return EBADF, including e.g. dup(2) or close(2). This avoids 221 * file descriptor races if we block in the second falloc(). 222 */ 223 224 error = falloc(l, &rf, &fd); 225 if (error) 226 goto free2; 227 retval[0] = fd; 228 rf->f_flag = FREAD; 229 rf->f_type = DTYPE_PIPE; 230 rf->f_data = (caddr_t)rpipe; 231 rf->f_ops = &pipeops; 232 233 error = falloc(l, &wf, &fd); 234 if (error) 235 goto free3; 236 retval[1] = fd; 237 wf->f_flag = FWRITE; 238 wf->f_type = DTYPE_PIPE; 239 wf->f_data = (caddr_t)wpipe; 240 wf->f_ops = &pipeops; 241 242 rpipe->pipe_peer = wpipe; 243 wpipe->pipe_peer = rpipe; 244 245 FILE_SET_MATURE(rf); 246 FILE_SET_MATURE(wf); 247 FILE_UNUSE(rf, l); 248 FILE_UNUSE(wf, l); 249 return (0); 250 free3: 251 FILE_UNUSE(rf, l); 252 ffree(rf); 253 fdremove(l->l_proc->p_fd, retval[0]); 254 free2: 255 pipeclose(NULL, wpipe); 256 pipeclose(NULL, rpipe); 257 258 return (error); 259 } 260 261 /* 262 * Allocate kva for pipe circular buffer, the space is pageable 263 * This routine will 'realloc' the size of a pipe safely, if it fails 264 * it will retain the old buffer. 265 * If it fails it will return ENOMEM. 266 */ 267 static int 268 pipespace(struct pipe *pipe, int size) 269 { 270 caddr_t buffer; 271 /* 272 * Allocate pageable virtual address space. Physical memory is 273 * allocated on demand. 274 */ 275 buffer = (caddr_t) uvm_km_alloc(kernel_map, round_page(size), 0, 276 UVM_KMF_PAGEABLE); 277 if (buffer == NULL) 278 return (ENOMEM); 279 280 /* free old resources if we're resizing */ 281 pipe_free_kmem(pipe); 282 pipe->pipe_buffer.buffer = buffer; 283 pipe->pipe_buffer.size = size; 284 pipe->pipe_buffer.in = 0; 285 pipe->pipe_buffer.out = 0; 286 pipe->pipe_buffer.cnt = 0; 287 amountpipekva += pipe->pipe_buffer.size; 288 return (0); 289 } 290 291 /* 292 * Initialize and allocate VM and memory for pipe. 293 */ 294 static int 295 pipe_create(struct pipe **pipep, int allockva) 296 { 297 struct pipe *pipe; 298 int error; 299 300 pipe = *pipep = pool_get(&pipe_pool, PR_WAITOK); 301 302 /* Initialize */ 303 memset(pipe, 0, sizeof(struct pipe)); 304 pipe->pipe_state = PIPE_SIGNALR; 305 306 getmicrotime(&pipe->pipe_ctime); 307 pipe->pipe_atime = pipe->pipe_ctime; 308 pipe->pipe_mtime = pipe->pipe_ctime; 309 simple_lock_init(&pipe->pipe_slock); 310 311 if (allockva && (error = pipespace(pipe, PIPE_SIZE))) 312 return (error); 313 314 return (0); 315 } 316 317 318 /* 319 * Lock a pipe for I/O, blocking other access 320 * Called with pipe spin lock held. 321 * Return with pipe spin lock released on success. 322 */ 323 static int 324 pipelock(struct pipe *pipe, int catch) 325 { 326 327 LOCK_ASSERT(simple_lock_held(&pipe->pipe_slock)); 328 329 while (pipe->pipe_state & PIPE_LOCKFL) { 330 int error; 331 const int pcatch = catch ? PCATCH : 0; 332 333 pipe->pipe_state |= PIPE_LWANT; 334 error = ltsleep(pipe, PSOCK | pcatch, "pipelk", 0, 335 &pipe->pipe_slock); 336 if (error != 0) 337 return error; 338 } 339 340 pipe->pipe_state |= PIPE_LOCKFL; 341 simple_unlock(&pipe->pipe_slock); 342 343 return 0; 344 } 345 346 /* 347 * unlock a pipe I/O lock 348 */ 349 static inline void 350 pipeunlock(struct pipe *pipe) 351 { 352 353 KASSERT(pipe->pipe_state & PIPE_LOCKFL); 354 355 pipe->pipe_state &= ~PIPE_LOCKFL; 356 if (pipe->pipe_state & PIPE_LWANT) { 357 pipe->pipe_state &= ~PIPE_LWANT; 358 wakeup(pipe); 359 } 360 } 361 362 /* 363 * Select/poll wakup. This also sends SIGIO to peer connected to 364 * 'sigpipe' side of pipe. 365 */ 366 static void 367 pipeselwakeup(struct pipe *selp, struct pipe *sigp, int code) 368 { 369 int band; 370 371 selnotify(&selp->pipe_sel, NOTE_SUBMIT); 372 373 if (sigp == NULL || (sigp->pipe_state & PIPE_ASYNC) == 0) 374 return; 375 376 switch (code) { 377 case POLL_IN: 378 band = POLLIN|POLLRDNORM; 379 break; 380 case POLL_OUT: 381 band = POLLOUT|POLLWRNORM; 382 break; 383 case POLL_HUP: 384 band = POLLHUP; 385 break; 386 #if POLL_HUP != POLL_ERR 387 case POLL_ERR: 388 band = POLLERR; 389 break; 390 #endif 391 default: 392 band = 0; 393 #ifdef DIAGNOSTIC 394 printf("bad siginfo code %d in pipe notification.\n", code); 395 #endif 396 break; 397 } 398 399 fownsignal(sigp->pipe_pgid, SIGIO, code, band, selp); 400 } 401 402 /* ARGSUSED */ 403 static int 404 pipe_read(struct file *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, 405 int flags) 406 { 407 struct pipe *rpipe = (struct pipe *) fp->f_data; 408 struct pipebuf *bp = &rpipe->pipe_buffer; 409 int error; 410 size_t nread = 0; 411 size_t size; 412 size_t ocnt; 413 414 PIPE_LOCK(rpipe); 415 ++rpipe->pipe_busy; 416 ocnt = bp->cnt; 417 418 again: 419 error = pipelock(rpipe, 1); 420 if (error) 421 goto unlocked_error; 422 423 while (uio->uio_resid) { 424 /* 425 * normal pipe buffer receive 426 */ 427 if (bp->cnt > 0) { 428 size = bp->size - bp->out; 429 if (size > bp->cnt) 430 size = bp->cnt; 431 if (size > uio->uio_resid) 432 size = uio->uio_resid; 433 434 error = uiomove(&bp->buffer[bp->out], size, uio); 435 if (error) 436 break; 437 438 bp->out += size; 439 if (bp->out >= bp->size) 440 bp->out = 0; 441 442 bp->cnt -= size; 443 444 /* 445 * If there is no more to read in the pipe, reset 446 * its pointers to the beginning. This improves 447 * cache hit stats. 448 */ 449 if (bp->cnt == 0) { 450 bp->in = 0; 451 bp->out = 0; 452 } 453 nread += size; 454 #ifndef PIPE_NODIRECT 455 } else if ((rpipe->pipe_state & PIPE_DIRECTR) != 0) { 456 /* 457 * Direct copy, bypassing a kernel buffer. 458 */ 459 caddr_t va; 460 461 KASSERT(rpipe->pipe_state & PIPE_DIRECTW); 462 463 size = rpipe->pipe_map.cnt; 464 if (size > uio->uio_resid) 465 size = uio->uio_resid; 466 467 va = (caddr_t) rpipe->pipe_map.kva + 468 rpipe->pipe_map.pos; 469 error = uiomove(va, size, uio); 470 if (error) 471 break; 472 nread += size; 473 rpipe->pipe_map.pos += size; 474 rpipe->pipe_map.cnt -= size; 475 if (rpipe->pipe_map.cnt == 0) { 476 PIPE_LOCK(rpipe); 477 rpipe->pipe_state &= ~PIPE_DIRECTR; 478 wakeup(rpipe); 479 PIPE_UNLOCK(rpipe); 480 } 481 #endif 482 } else { 483 /* 484 * Break if some data was read. 485 */ 486 if (nread > 0) 487 break; 488 489 PIPE_LOCK(rpipe); 490 491 /* 492 * detect EOF condition 493 * read returns 0 on EOF, no need to set error 494 */ 495 if (rpipe->pipe_state & PIPE_EOF) { 496 PIPE_UNLOCK(rpipe); 497 break; 498 } 499 500 /* 501 * don't block on non-blocking I/O 502 */ 503 if (fp->f_flag & FNONBLOCK) { 504 PIPE_UNLOCK(rpipe); 505 error = EAGAIN; 506 break; 507 } 508 509 /* 510 * Unlock the pipe buffer for our remaining processing. 511 * We will either break out with an error or we will 512 * sleep and relock to loop. 513 */ 514 pipeunlock(rpipe); 515 516 /* 517 * The PIPE_DIRECTR flag is not under the control 518 * of the long-term lock (see pipe_direct_write()), 519 * so re-check now while holding the spin lock. 520 */ 521 if ((rpipe->pipe_state & PIPE_DIRECTR) != 0) 522 goto again; 523 524 /* 525 * We want to read more, wake up select/poll. 526 */ 527 pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_IN); 528 529 /* 530 * If the "write-side" is blocked, wake it up now. 531 */ 532 if (rpipe->pipe_state & PIPE_WANTW) { 533 rpipe->pipe_state &= ~PIPE_WANTW; 534 wakeup(rpipe); 535 } 536 537 /* Now wait until the pipe is filled */ 538 rpipe->pipe_state |= PIPE_WANTR; 539 error = ltsleep(rpipe, PSOCK | PCATCH, 540 "piperd", 0, &rpipe->pipe_slock); 541 if (error != 0) 542 goto unlocked_error; 543 goto again; 544 } 545 } 546 547 if (error == 0) 548 getmicrotime(&rpipe->pipe_atime); 549 550 PIPE_LOCK(rpipe); 551 pipeunlock(rpipe); 552 553 unlocked_error: 554 --rpipe->pipe_busy; 555 556 /* 557 * PIPE_WANTCLOSE processing only makes sense if pipe_busy is 0. 558 */ 559 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANTCLOSE)) { 560 rpipe->pipe_state &= ~(PIPE_WANTCLOSE|PIPE_WANTW); 561 wakeup(rpipe); 562 } else if (bp->cnt < MINPIPESIZE) { 563 /* 564 * Handle write blocking hysteresis. 565 */ 566 if (rpipe->pipe_state & PIPE_WANTW) { 567 rpipe->pipe_state &= ~PIPE_WANTW; 568 wakeup(rpipe); 569 } 570 } 571 572 /* 573 * If anything was read off the buffer, signal to the writer it's 574 * possible to write more data. Also send signal if we are here for the 575 * first time after last write. 576 */ 577 if ((bp->size - bp->cnt) >= PIPE_BUF 578 && (ocnt != bp->cnt || (rpipe->pipe_state & PIPE_SIGNALR))) { 579 pipeselwakeup(rpipe, rpipe->pipe_peer, POLL_OUT); 580 rpipe->pipe_state &= ~PIPE_SIGNALR; 581 } 582 583 PIPE_UNLOCK(rpipe); 584 return (error); 585 } 586 587 #ifndef PIPE_NODIRECT 588 /* 589 * Allocate structure for loan transfer. 590 */ 591 static int 592 pipe_loan_alloc(struct pipe *wpipe, int npages) 593 { 594 vsize_t len; 595 596 len = (vsize_t)npages << PAGE_SHIFT; 597 wpipe->pipe_map.kva = uvm_km_alloc(kernel_map, len, 0, 598 UVM_KMF_VAONLY | UVM_KMF_WAITVA); 599 if (wpipe->pipe_map.kva == 0) 600 return (ENOMEM); 601 602 amountpipekva += len; 603 wpipe->pipe_map.npages = npages; 604 wpipe->pipe_map.pgs = malloc(npages * sizeof(struct vm_page *), M_PIPE, 605 M_WAITOK); 606 return (0); 607 } 608 609 /* 610 * Free resources allocated for loan transfer. 611 */ 612 static void 613 pipe_loan_free(struct pipe *wpipe) 614 { 615 vsize_t len; 616 617 len = (vsize_t)wpipe->pipe_map.npages << PAGE_SHIFT; 618 uvm_km_free(kernel_map, wpipe->pipe_map.kva, len, UVM_KMF_VAONLY); 619 wpipe->pipe_map.kva = 0; 620 amountpipekva -= len; 621 free(wpipe->pipe_map.pgs, M_PIPE); 622 wpipe->pipe_map.pgs = NULL; 623 } 624 625 /* 626 * NetBSD direct write, using uvm_loan() mechanism. 627 * This implements the pipe buffer write mechanism. Note that only 628 * a direct write OR a normal pipe write can be pending at any given time. 629 * If there are any characters in the pipe buffer, the direct write will 630 * be deferred until the receiving process grabs all of the bytes from 631 * the pipe buffer. Then the direct mapping write is set-up. 632 * 633 * Called with the long-term pipe lock held. 634 */ 635 static int 636 pipe_direct_write(struct file *fp, struct pipe *wpipe, struct uio *uio) 637 { 638 int error, npages, j; 639 struct vm_page **pgs; 640 vaddr_t bbase, kva, base, bend; 641 vsize_t blen, bcnt; 642 voff_t bpos; 643 644 KASSERT(wpipe->pipe_map.cnt == 0); 645 646 /* 647 * Handle first PIPE_CHUNK_SIZE bytes of buffer. Deal with buffers 648 * not aligned to PAGE_SIZE. 649 */ 650 bbase = (vaddr_t)uio->uio_iov->iov_base; 651 base = trunc_page(bbase); 652 bend = round_page(bbase + uio->uio_iov->iov_len); 653 blen = bend - base; 654 bpos = bbase - base; 655 656 if (blen > PIPE_DIRECT_CHUNK) { 657 blen = PIPE_DIRECT_CHUNK; 658 bend = base + blen; 659 bcnt = PIPE_DIRECT_CHUNK - bpos; 660 } else { 661 bcnt = uio->uio_iov->iov_len; 662 } 663 npages = blen >> PAGE_SHIFT; 664 665 /* 666 * Free the old kva if we need more pages than we have 667 * allocated. 668 */ 669 if (wpipe->pipe_map.kva != 0 && npages > wpipe->pipe_map.npages) 670 pipe_loan_free(wpipe); 671 672 /* Allocate new kva. */ 673 if (wpipe->pipe_map.kva == 0) { 674 error = pipe_loan_alloc(wpipe, npages); 675 if (error) 676 return (error); 677 } 678 679 /* Loan the write buffer memory from writer process */ 680 pgs = wpipe->pipe_map.pgs; 681 error = uvm_loan(&uio->uio_vmspace->vm_map, base, blen, 682 pgs, UVM_LOAN_TOPAGE); 683 if (error) { 684 pipe_loan_free(wpipe); 685 return (ENOMEM); /* so that caller fallback to ordinary write */ 686 } 687 688 /* Enter the loaned pages to kva */ 689 kva = wpipe->pipe_map.kva; 690 for (j = 0; j < npages; j++, kva += PAGE_SIZE) { 691 pmap_kenter_pa(kva, VM_PAGE_TO_PHYS(pgs[j]), VM_PROT_READ); 692 } 693 pmap_update(pmap_kernel()); 694 695 /* Now we can put the pipe in direct write mode */ 696 wpipe->pipe_map.pos = bpos; 697 wpipe->pipe_map.cnt = bcnt; 698 wpipe->pipe_state |= PIPE_DIRECTW; 699 700 /* 701 * But before we can let someone do a direct read, 702 * we have to wait until the pipe is drained. 703 */ 704 705 /* Relase the pipe lock while we wait */ 706 PIPE_LOCK(wpipe); 707 pipeunlock(wpipe); 708 709 while (error == 0 && wpipe->pipe_buffer.cnt > 0) { 710 if (wpipe->pipe_state & PIPE_WANTR) { 711 wpipe->pipe_state &= ~PIPE_WANTR; 712 wakeup(wpipe); 713 } 714 715 wpipe->pipe_state |= PIPE_WANTW; 716 error = ltsleep(wpipe, PSOCK | PCATCH, "pipdwc", 0, 717 &wpipe->pipe_slock); 718 if (error == 0 && wpipe->pipe_state & PIPE_EOF) 719 error = EPIPE; 720 } 721 722 /* Pipe is drained; next read will off the direct buffer */ 723 wpipe->pipe_state |= PIPE_DIRECTR; 724 725 /* Wait until the reader is done */ 726 while (error == 0 && (wpipe->pipe_state & PIPE_DIRECTR)) { 727 if (wpipe->pipe_state & PIPE_WANTR) { 728 wpipe->pipe_state &= ~PIPE_WANTR; 729 wakeup(wpipe); 730 } 731 pipeselwakeup(wpipe, wpipe, POLL_IN); 732 error = ltsleep(wpipe, PSOCK | PCATCH, "pipdwt", 0, 733 &wpipe->pipe_slock); 734 if (error == 0 && wpipe->pipe_state & PIPE_EOF) 735 error = EPIPE; 736 } 737 738 /* Take pipe out of direct write mode */ 739 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTR); 740 741 /* Acquire the pipe lock and cleanup */ 742 (void)pipelock(wpipe, 0); 743 if (pgs != NULL) { 744 pmap_kremove(wpipe->pipe_map.kva, blen); 745 uvm_unloan(pgs, npages, UVM_LOAN_TOPAGE); 746 } 747 if (error || amountpipekva > maxpipekva) 748 pipe_loan_free(wpipe); 749 750 if (error) { 751 pipeselwakeup(wpipe, wpipe, POLL_ERR); 752 753 /* 754 * If nothing was read from what we offered, return error 755 * straight on. Otherwise update uio resid first. Caller 756 * will deal with the error condition, returning short 757 * write, error, or restarting the write(2) as appropriate. 758 */ 759 if (wpipe->pipe_map.cnt == bcnt) { 760 wpipe->pipe_map.cnt = 0; 761 wakeup(wpipe); 762 return (error); 763 } 764 765 bcnt -= wpipe->pipe_map.cnt; 766 } 767 768 uio->uio_resid -= bcnt; 769 /* uio_offset not updated, not set/used for write(2) */ 770 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + bcnt; 771 uio->uio_iov->iov_len -= bcnt; 772 if (uio->uio_iov->iov_len == 0) { 773 uio->uio_iov++; 774 uio->uio_iovcnt--; 775 } 776 777 wpipe->pipe_map.cnt = 0; 778 return (error); 779 } 780 #endif /* !PIPE_NODIRECT */ 781 782 static int 783 pipe_write(struct file *fp, off_t *offset, struct uio *uio, kauth_cred_t cred, 784 int flags) 785 { 786 struct pipe *wpipe, *rpipe; 787 struct pipebuf *bp; 788 int error; 789 790 /* We want to write to our peer */ 791 rpipe = (struct pipe *) fp->f_data; 792 793 retry: 794 error = 0; 795 PIPE_LOCK(rpipe); 796 wpipe = rpipe->pipe_peer; 797 798 /* 799 * Detect loss of pipe read side, issue SIGPIPE if lost. 800 */ 801 if (wpipe == NULL) 802 error = EPIPE; 803 else if (simple_lock_try(&wpipe->pipe_slock) == 0) { 804 /* Deal with race for peer */ 805 PIPE_UNLOCK(rpipe); 806 goto retry; 807 } else if ((wpipe->pipe_state & PIPE_EOF) != 0) { 808 PIPE_UNLOCK(wpipe); 809 error = EPIPE; 810 } 811 812 PIPE_UNLOCK(rpipe); 813 if (error != 0) 814 return (error); 815 816 ++wpipe->pipe_busy; 817 818 /* Aquire the long-term pipe lock */ 819 if ((error = pipelock(wpipe,1)) != 0) { 820 --wpipe->pipe_busy; 821 if (wpipe->pipe_busy == 0 822 && (wpipe->pipe_state & PIPE_WANTCLOSE)) { 823 wpipe->pipe_state &= ~(PIPE_WANTCLOSE | PIPE_WANTR); 824 wakeup(wpipe); 825 } 826 PIPE_UNLOCK(wpipe); 827 return (error); 828 } 829 830 bp = &wpipe->pipe_buffer; 831 832 /* 833 * If it is advantageous to resize the pipe buffer, do so. 834 */ 835 if ((uio->uio_resid > PIPE_SIZE) && 836 (nbigpipe < maxbigpipes) && 837 #ifndef PIPE_NODIRECT 838 (wpipe->pipe_state & PIPE_DIRECTW) == 0 && 839 #endif 840 (bp->size <= PIPE_SIZE) && (bp->cnt == 0)) { 841 842 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 843 nbigpipe++; 844 } 845 846 while (uio->uio_resid) { 847 size_t space; 848 849 #ifndef PIPE_NODIRECT 850 /* 851 * Pipe buffered writes cannot be coincidental with 852 * direct writes. Also, only one direct write can be 853 * in progress at any one time. We wait until the currently 854 * executing direct write is completed before continuing. 855 * 856 * We break out if a signal occurs or the reader goes away. 857 */ 858 while (error == 0 && wpipe->pipe_state & PIPE_DIRECTW) { 859 PIPE_LOCK(wpipe); 860 if (wpipe->pipe_state & PIPE_WANTR) { 861 wpipe->pipe_state &= ~PIPE_WANTR; 862 wakeup(wpipe); 863 } 864 pipeunlock(wpipe); 865 error = ltsleep(wpipe, PSOCK | PCATCH, 866 "pipbww", 0, &wpipe->pipe_slock); 867 868 (void)pipelock(wpipe, 0); 869 if (wpipe->pipe_state & PIPE_EOF) 870 error = EPIPE; 871 } 872 if (error) 873 break; 874 875 /* 876 * If the transfer is large, we can gain performance if 877 * we do process-to-process copies directly. 878 * If the write is non-blocking, we don't use the 879 * direct write mechanism. 880 * 881 * The direct write mechanism will detect the reader going 882 * away on us. 883 */ 884 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && 885 (fp->f_flag & FNONBLOCK) == 0 && 886 (wpipe->pipe_map.kva || (amountpipekva < limitpipekva))) { 887 error = pipe_direct_write(fp, wpipe, uio); 888 889 /* 890 * Break out if error occurred, unless it's ENOMEM. 891 * ENOMEM means we failed to allocate some resources 892 * for direct write, so we just fallback to ordinary 893 * write. If the direct write was successful, 894 * process rest of data via ordinary write. 895 */ 896 if (error == 0) 897 continue; 898 899 if (error != ENOMEM) 900 break; 901 } 902 #endif /* PIPE_NODIRECT */ 903 904 space = bp->size - bp->cnt; 905 906 /* Writes of size <= PIPE_BUF must be atomic. */ 907 if ((space < uio->uio_resid) && (uio->uio_resid <= PIPE_BUF)) 908 space = 0; 909 910 if (space > 0) { 911 int size; /* Transfer size */ 912 int segsize; /* first segment to transfer */ 913 914 /* 915 * Transfer size is minimum of uio transfer 916 * and free space in pipe buffer. 917 */ 918 if (space > uio->uio_resid) 919 size = uio->uio_resid; 920 else 921 size = space; 922 /* 923 * First segment to transfer is minimum of 924 * transfer size and contiguous space in 925 * pipe buffer. If first segment to transfer 926 * is less than the transfer size, we've got 927 * a wraparound in the buffer. 928 */ 929 segsize = bp->size - bp->in; 930 if (segsize > size) 931 segsize = size; 932 933 /* Transfer first segment */ 934 error = uiomove(&bp->buffer[bp->in], segsize, uio); 935 936 if (error == 0 && segsize < size) { 937 /* 938 * Transfer remaining part now, to 939 * support atomic writes. Wraparound 940 * happened. 941 */ 942 #ifdef DEBUG 943 if (bp->in + segsize != bp->size) 944 panic("Expected pipe buffer wraparound disappeared"); 945 #endif 946 947 error = uiomove(&bp->buffer[0], 948 size - segsize, uio); 949 } 950 if (error) 951 break; 952 953 bp->in += size; 954 if (bp->in >= bp->size) { 955 #ifdef DEBUG 956 if (bp->in != size - segsize + bp->size) 957 panic("Expected wraparound bad"); 958 #endif 959 bp->in = size - segsize; 960 } 961 962 bp->cnt += size; 963 #ifdef DEBUG 964 if (bp->cnt > bp->size) 965 panic("Pipe buffer overflow"); 966 #endif 967 } else { 968 /* 969 * If the "read-side" has been blocked, wake it up now. 970 */ 971 PIPE_LOCK(wpipe); 972 if (wpipe->pipe_state & PIPE_WANTR) { 973 wpipe->pipe_state &= ~PIPE_WANTR; 974 wakeup(wpipe); 975 } 976 PIPE_UNLOCK(wpipe); 977 978 /* 979 * don't block on non-blocking I/O 980 */ 981 if (fp->f_flag & FNONBLOCK) { 982 error = EAGAIN; 983 break; 984 } 985 986 /* 987 * We have no more space and have something to offer, 988 * wake up select/poll. 989 */ 990 if (bp->cnt) 991 pipeselwakeup(wpipe, wpipe, POLL_OUT); 992 993 PIPE_LOCK(wpipe); 994 pipeunlock(wpipe); 995 wpipe->pipe_state |= PIPE_WANTW; 996 error = ltsleep(wpipe, PSOCK | PCATCH, "pipewr", 0, 997 &wpipe->pipe_slock); 998 (void)pipelock(wpipe, 0); 999 if (error != 0) 1000 break; 1001 /* 1002 * If read side wants to go away, we just issue a signal 1003 * to ourselves. 1004 */ 1005 if (wpipe->pipe_state & PIPE_EOF) { 1006 error = EPIPE; 1007 break; 1008 } 1009 } 1010 } 1011 1012 PIPE_LOCK(wpipe); 1013 --wpipe->pipe_busy; 1014 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANTCLOSE)) { 1015 wpipe->pipe_state &= ~(PIPE_WANTCLOSE | PIPE_WANTR); 1016 wakeup(wpipe); 1017 } else if (bp->cnt > 0) { 1018 /* 1019 * If we have put any characters in the buffer, we wake up 1020 * the reader. 1021 */ 1022 if (wpipe->pipe_state & PIPE_WANTR) { 1023 wpipe->pipe_state &= ~PIPE_WANTR; 1024 wakeup(wpipe); 1025 } 1026 } 1027 1028 /* 1029 * Don't return EPIPE if I/O was successful 1030 */ 1031 if (error == EPIPE && bp->cnt == 0 && uio->uio_resid == 0) 1032 error = 0; 1033 1034 if (error == 0) 1035 getmicrotime(&wpipe->pipe_mtime); 1036 1037 /* 1038 * We have something to offer, wake up select/poll. 1039 * wpipe->pipe_map.cnt is always 0 in this point (direct write 1040 * is only done synchronously), so check only wpipe->pipe_buffer.cnt 1041 */ 1042 if (bp->cnt) 1043 pipeselwakeup(wpipe, wpipe, POLL_OUT); 1044 1045 /* 1046 * Arrange for next read(2) to do a signal. 1047 */ 1048 wpipe->pipe_state |= PIPE_SIGNALR; 1049 1050 pipeunlock(wpipe); 1051 PIPE_UNLOCK(wpipe); 1052 return (error); 1053 } 1054 1055 /* 1056 * we implement a very minimal set of ioctls for compatibility with sockets. 1057 */ 1058 int 1059 pipe_ioctl(struct file *fp, u_long cmd, void *data, struct lwp *l) 1060 { 1061 struct pipe *pipe = (struct pipe *)fp->f_data; 1062 struct proc *p = l->l_proc; 1063 1064 switch (cmd) { 1065 1066 case FIONBIO: 1067 return (0); 1068 1069 case FIOASYNC: 1070 PIPE_LOCK(pipe); 1071 if (*(int *)data) { 1072 pipe->pipe_state |= PIPE_ASYNC; 1073 } else { 1074 pipe->pipe_state &= ~PIPE_ASYNC; 1075 } 1076 PIPE_UNLOCK(pipe); 1077 return (0); 1078 1079 case FIONREAD: 1080 PIPE_LOCK(pipe); 1081 #ifndef PIPE_NODIRECT 1082 if (pipe->pipe_state & PIPE_DIRECTW) 1083 *(int *)data = pipe->pipe_map.cnt; 1084 else 1085 #endif 1086 *(int *)data = pipe->pipe_buffer.cnt; 1087 PIPE_UNLOCK(pipe); 1088 return (0); 1089 1090 case FIONWRITE: 1091 /* Look at other side */ 1092 pipe = pipe->pipe_peer; 1093 PIPE_LOCK(pipe); 1094 #ifndef PIPE_NODIRECT 1095 if (pipe->pipe_state & PIPE_DIRECTW) 1096 *(int *)data = pipe->pipe_map.cnt; 1097 else 1098 #endif 1099 *(int *)data = pipe->pipe_buffer.cnt; 1100 PIPE_UNLOCK(pipe); 1101 return (0); 1102 1103 case FIONSPACE: 1104 /* Look at other side */ 1105 pipe = pipe->pipe_peer; 1106 PIPE_LOCK(pipe); 1107 #ifndef PIPE_NODIRECT 1108 /* 1109 * If we're in direct-mode, we don't really have a 1110 * send queue, and any other write will block. Thus 1111 * zero seems like the best answer. 1112 */ 1113 if (pipe->pipe_state & PIPE_DIRECTW) 1114 *(int *)data = 0; 1115 else 1116 #endif 1117 *(int *)data = pipe->pipe_buffer.size - 1118 pipe->pipe_buffer.cnt; 1119 PIPE_UNLOCK(pipe); 1120 return (0); 1121 1122 case TIOCSPGRP: 1123 case FIOSETOWN: 1124 return fsetown(p, &pipe->pipe_pgid, cmd, data); 1125 1126 case TIOCGPGRP: 1127 case FIOGETOWN: 1128 return fgetown(p, pipe->pipe_pgid, cmd, data); 1129 1130 } 1131 return (EPASSTHROUGH); 1132 } 1133 1134 int 1135 pipe_poll(struct file *fp, int events, struct lwp *l) 1136 { 1137 struct pipe *rpipe = (struct pipe *)fp->f_data; 1138 struct pipe *wpipe; 1139 int eof = 0; 1140 int revents = 0; 1141 1142 retry: 1143 PIPE_LOCK(rpipe); 1144 wpipe = rpipe->pipe_peer; 1145 if (wpipe != NULL && simple_lock_try(&wpipe->pipe_slock) == 0) { 1146 /* Deal with race for peer */ 1147 PIPE_UNLOCK(rpipe); 1148 goto retry; 1149 } 1150 1151 if (events & (POLLIN | POLLRDNORM)) 1152 if ((rpipe->pipe_buffer.cnt > 0) || 1153 #ifndef PIPE_NODIRECT 1154 (rpipe->pipe_state & PIPE_DIRECTR) || 1155 #endif 1156 (rpipe->pipe_state & PIPE_EOF)) 1157 revents |= events & (POLLIN | POLLRDNORM); 1158 1159 eof |= (rpipe->pipe_state & PIPE_EOF); 1160 PIPE_UNLOCK(rpipe); 1161 1162 if (wpipe == NULL) 1163 revents |= events & (POLLOUT | POLLWRNORM); 1164 else { 1165 if (events & (POLLOUT | POLLWRNORM)) 1166 if ((wpipe->pipe_state & PIPE_EOF) || ( 1167 #ifndef PIPE_NODIRECT 1168 (wpipe->pipe_state & PIPE_DIRECTW) == 0 && 1169 #endif 1170 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1171 revents |= events & (POLLOUT | POLLWRNORM); 1172 1173 eof |= (wpipe->pipe_state & PIPE_EOF); 1174 PIPE_UNLOCK(wpipe); 1175 } 1176 1177 if (wpipe == NULL || eof) 1178 revents |= POLLHUP; 1179 1180 if (revents == 0) { 1181 if (events & (POLLIN | POLLRDNORM)) 1182 selrecord(l, &rpipe->pipe_sel); 1183 1184 if (events & (POLLOUT | POLLWRNORM)) 1185 selrecord(l, &wpipe->pipe_sel); 1186 } 1187 1188 return (revents); 1189 } 1190 1191 static int 1192 pipe_stat(struct file *fp, struct stat *ub, struct lwp *l) 1193 { 1194 struct pipe *pipe = (struct pipe *)fp->f_data; 1195 1196 memset((caddr_t)ub, 0, sizeof(*ub)); 1197 ub->st_mode = S_IFIFO | S_IRUSR | S_IWUSR; 1198 ub->st_blksize = pipe->pipe_buffer.size; 1199 if (ub->st_blksize == 0 && pipe->pipe_peer) 1200 ub->st_blksize = pipe->pipe_peer->pipe_buffer.size; 1201 ub->st_size = pipe->pipe_buffer.cnt; 1202 ub->st_blocks = (ub->st_size) ? 1 : 0; 1203 TIMEVAL_TO_TIMESPEC(&pipe->pipe_atime, &ub->st_atimespec); 1204 TIMEVAL_TO_TIMESPEC(&pipe->pipe_mtime, &ub->st_mtimespec); 1205 TIMEVAL_TO_TIMESPEC(&pipe->pipe_ctime, &ub->st_ctimespec); 1206 ub->st_uid = kauth_cred_geteuid(fp->f_cred); 1207 ub->st_gid = kauth_cred_getegid(fp->f_cred); 1208 /* 1209 * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen. 1210 * XXX (st_dev, st_ino) should be unique. 1211 */ 1212 return (0); 1213 } 1214 1215 /* ARGSUSED */ 1216 static int 1217 pipe_close(struct file *fp, struct lwp *l) 1218 { 1219 struct pipe *pipe = (struct pipe *)fp->f_data; 1220 1221 fp->f_data = NULL; 1222 pipeclose(fp, pipe); 1223 return (0); 1224 } 1225 1226 static void 1227 pipe_free_kmem(struct pipe *pipe) 1228 { 1229 1230 if (pipe->pipe_buffer.buffer != NULL) { 1231 if (pipe->pipe_buffer.size > PIPE_SIZE) 1232 --nbigpipe; 1233 amountpipekva -= pipe->pipe_buffer.size; 1234 uvm_km_free(kernel_map, 1235 (vaddr_t)pipe->pipe_buffer.buffer, 1236 pipe->pipe_buffer.size, UVM_KMF_PAGEABLE); 1237 pipe->pipe_buffer.buffer = NULL; 1238 } 1239 #ifndef PIPE_NODIRECT 1240 if (pipe->pipe_map.kva != 0) { 1241 pipe_loan_free(pipe); 1242 pipe->pipe_map.cnt = 0; 1243 pipe->pipe_map.kva = 0; 1244 pipe->pipe_map.pos = 0; 1245 pipe->pipe_map.npages = 0; 1246 } 1247 #endif /* !PIPE_NODIRECT */ 1248 } 1249 1250 /* 1251 * shutdown the pipe 1252 */ 1253 static void 1254 pipeclose(struct file *fp, struct pipe *pipe) 1255 { 1256 struct pipe *ppipe; 1257 1258 if (pipe == NULL) 1259 return; 1260 1261 retry: 1262 PIPE_LOCK(pipe); 1263 1264 pipeselwakeup(pipe, pipe, POLL_HUP); 1265 1266 /* 1267 * If the other side is blocked, wake it up saying that 1268 * we want to close it down. 1269 */ 1270 pipe->pipe_state |= PIPE_EOF; 1271 while (pipe->pipe_busy) { 1272 wakeup(pipe); 1273 pipe->pipe_state |= PIPE_WANTCLOSE; 1274 ltsleep(pipe, PSOCK, "pipecl", 0, &pipe->pipe_slock); 1275 } 1276 1277 /* 1278 * Disconnect from peer 1279 */ 1280 if ((ppipe = pipe->pipe_peer) != NULL) { 1281 /* Deal with race for peer */ 1282 if (simple_lock_try(&ppipe->pipe_slock) == 0) { 1283 PIPE_UNLOCK(pipe); 1284 goto retry; 1285 } 1286 pipeselwakeup(ppipe, ppipe, POLL_HUP); 1287 1288 ppipe->pipe_state |= PIPE_EOF; 1289 wakeup(ppipe); 1290 ppipe->pipe_peer = NULL; 1291 PIPE_UNLOCK(ppipe); 1292 } 1293 1294 KASSERT((pipe->pipe_state & PIPE_LOCKFL) == 0); 1295 1296 PIPE_UNLOCK(pipe); 1297 1298 /* 1299 * free resources 1300 */ 1301 pipe_free_kmem(pipe); 1302 pool_put(&pipe_pool, pipe); 1303 } 1304 1305 static void 1306 filt_pipedetach(struct knote *kn) 1307 { 1308 struct pipe *pipe = (struct pipe *)kn->kn_fp->f_data; 1309 1310 switch(kn->kn_filter) { 1311 case EVFILT_WRITE: 1312 /* need the peer structure, not our own */ 1313 pipe = pipe->pipe_peer; 1314 /* XXXSMP: race for peer */ 1315 1316 /* if reader end already closed, just return */ 1317 if (pipe == NULL) 1318 return; 1319 1320 break; 1321 default: 1322 /* nothing to do */ 1323 break; 1324 } 1325 1326 #ifdef DIAGNOSTIC 1327 if (kn->kn_hook != pipe) 1328 panic("filt_pipedetach: inconsistent knote"); 1329 #endif 1330 1331 PIPE_LOCK(pipe); 1332 SLIST_REMOVE(&pipe->pipe_sel.sel_klist, kn, knote, kn_selnext); 1333 PIPE_UNLOCK(pipe); 1334 } 1335 1336 /*ARGSUSED*/ 1337 static int 1338 filt_piperead(struct knote *kn, long hint) 1339 { 1340 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1341 struct pipe *wpipe = rpipe->pipe_peer; 1342 1343 if ((hint & NOTE_SUBMIT) == 0) 1344 PIPE_LOCK(rpipe); 1345 kn->kn_data = rpipe->pipe_buffer.cnt; 1346 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1347 kn->kn_data = rpipe->pipe_map.cnt; 1348 1349 /* XXXSMP: race for peer */ 1350 if ((rpipe->pipe_state & PIPE_EOF) || 1351 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1352 kn->kn_flags |= EV_EOF; 1353 if ((hint & NOTE_SUBMIT) == 0) 1354 PIPE_UNLOCK(rpipe); 1355 return (1); 1356 } 1357 if ((hint & NOTE_SUBMIT) == 0) 1358 PIPE_UNLOCK(rpipe); 1359 return (kn->kn_data > 0); 1360 } 1361 1362 /*ARGSUSED*/ 1363 static int 1364 filt_pipewrite(struct knote *kn, long hint) 1365 { 1366 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1367 struct pipe *wpipe = rpipe->pipe_peer; 1368 1369 if ((hint & NOTE_SUBMIT) == 0) 1370 PIPE_LOCK(rpipe); 1371 /* XXXSMP: race for peer */ 1372 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1373 kn->kn_data = 0; 1374 kn->kn_flags |= EV_EOF; 1375 if ((hint & NOTE_SUBMIT) == 0) 1376 PIPE_UNLOCK(rpipe); 1377 return (1); 1378 } 1379 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1380 if (wpipe->pipe_state & PIPE_DIRECTW) 1381 kn->kn_data = 0; 1382 1383 if ((hint & NOTE_SUBMIT) == 0) 1384 PIPE_UNLOCK(rpipe); 1385 return (kn->kn_data >= PIPE_BUF); 1386 } 1387 1388 static const struct filterops pipe_rfiltops = 1389 { 1, NULL, filt_pipedetach, filt_piperead }; 1390 static const struct filterops pipe_wfiltops = 1391 { 1, NULL, filt_pipedetach, filt_pipewrite }; 1392 1393 /*ARGSUSED*/ 1394 static int 1395 pipe_kqfilter(struct file *fp, struct knote *kn) 1396 { 1397 struct pipe *pipe; 1398 1399 pipe = (struct pipe *)kn->kn_fp->f_data; 1400 switch (kn->kn_filter) { 1401 case EVFILT_READ: 1402 kn->kn_fop = &pipe_rfiltops; 1403 break; 1404 case EVFILT_WRITE: 1405 kn->kn_fop = &pipe_wfiltops; 1406 /* XXXSMP: race for peer */ 1407 pipe = pipe->pipe_peer; 1408 if (pipe == NULL) { 1409 /* other end of pipe has been closed */ 1410 return (EBADF); 1411 } 1412 break; 1413 default: 1414 return (1); 1415 } 1416 kn->kn_hook = pipe; 1417 1418 PIPE_LOCK(pipe); 1419 SLIST_INSERT_HEAD(&pipe->pipe_sel.sel_klist, kn, kn_selnext); 1420 PIPE_UNLOCK(pipe); 1421 return (0); 1422 } 1423 1424 /* 1425 * Handle pipe sysctls. 1426 */ 1427 SYSCTL_SETUP(sysctl_kern_pipe_setup, "sysctl kern.pipe subtree setup") 1428 { 1429 1430 sysctl_createv(clog, 0, NULL, NULL, 1431 CTLFLAG_PERMANENT, 1432 CTLTYPE_NODE, "kern", NULL, 1433 NULL, 0, NULL, 0, 1434 CTL_KERN, CTL_EOL); 1435 sysctl_createv(clog, 0, NULL, NULL, 1436 CTLFLAG_PERMANENT, 1437 CTLTYPE_NODE, "pipe", 1438 SYSCTL_DESCR("Pipe settings"), 1439 NULL, 0, NULL, 0, 1440 CTL_KERN, KERN_PIPE, CTL_EOL); 1441 1442 sysctl_createv(clog, 0, NULL, NULL, 1443 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1444 CTLTYPE_INT, "maxkvasz", 1445 SYSCTL_DESCR("Maximum amount of kernel memory to be " 1446 "used for pipes"), 1447 NULL, 0, &maxpipekva, 0, 1448 CTL_KERN, KERN_PIPE, KERN_PIPE_MAXKVASZ, CTL_EOL); 1449 sysctl_createv(clog, 0, NULL, NULL, 1450 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1451 CTLTYPE_INT, "maxloankvasz", 1452 SYSCTL_DESCR("Limit for direct transfers via page loan"), 1453 NULL, 0, &limitpipekva, 0, 1454 CTL_KERN, KERN_PIPE, KERN_PIPE_LIMITKVA, CTL_EOL); 1455 sysctl_createv(clog, 0, NULL, NULL, 1456 CTLFLAG_PERMANENT|CTLFLAG_READWRITE, 1457 CTLTYPE_INT, "maxbigpipes", 1458 SYSCTL_DESCR("Maximum number of \"big\" pipes"), 1459 NULL, 0, &maxbigpipes, 0, 1460 CTL_KERN, KERN_PIPE, KERN_PIPE_MAXBIGPIPES, CTL_EOL); 1461 sysctl_createv(clog, 0, NULL, NULL, 1462 CTLFLAG_PERMANENT, 1463 CTLTYPE_INT, "nbigpipes", 1464 SYSCTL_DESCR("Number of \"big\" pipes"), 1465 NULL, 0, &nbigpipe, 0, 1466 CTL_KERN, KERN_PIPE, KERN_PIPE_NBIGPIPES, CTL_EOL); 1467 sysctl_createv(clog, 0, NULL, NULL, 1468 CTLFLAG_PERMANENT, 1469 CTLTYPE_INT, "kvasize", 1470 SYSCTL_DESCR("Amount of kernel memory consumed by pipe " 1471 "buffers"), 1472 NULL, 0, &amountpipekva, 0, 1473 CTL_KERN, KERN_PIPE, KERN_PIPE_KVASIZE, CTL_EOL); 1474 } 1475