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: src/sys/kern/sys_pipe.c,v 1.60.2.13 2002/08/05 15:05:15 des Exp $ 20 * $DragonFly: src/sys/kern/sys_pipe.c,v 1.25 2004/11/12 00:09:24 dillon Exp $ 21 */ 22 23 /* 24 * This file contains a high-performance replacement for the socket-based 25 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support 26 * all features of sockets, but does do everything that pipes normally 27 * do. 28 */ 29 30 /* 31 * This code has two modes of operation, a small write mode and a large 32 * write mode. The small write mode acts like conventional pipes with 33 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the 34 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT 35 * and PIPE_SIZE in size, it is fully mapped and wired into the kernel, and 36 * the receiving process can copy it directly from the pages in the sending 37 * process. 38 * 39 * If the sending process receives a signal, it is possible that it will 40 * go away, and certainly its address space can change, because control 41 * is returned back to the user-mode side. In that case, the pipe code 42 * arranges to copy the buffer supplied by the user process, to a pageable 43 * kernel buffer, and the receiving process will grab the data from the 44 * pageable kernel buffer. Since signals don't happen all that often, 45 * the copy operation is normally eliminated. 46 * 47 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will 48 * happen for small transfers so that the system will not spend all of 49 * its time context switching. PIPE_SIZE is constrained by the 50 * amount of kernel virtual memory. 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/kernel.h> 56 #include <sys/proc.h> 57 #include <sys/fcntl.h> 58 #include <sys/file.h> 59 #include <sys/filedesc.h> 60 #include <sys/filio.h> 61 #include <sys/ttycom.h> 62 #include <sys/stat.h> 63 #include <sys/poll.h> 64 #include <sys/select.h> 65 #include <sys/signalvar.h> 66 #include <sys/sysproto.h> 67 #include <sys/pipe.h> 68 #include <sys/vnode.h> 69 #include <sys/uio.h> 70 #include <sys/event.h> 71 #include <sys/globaldata.h> 72 #include <sys/module.h> 73 #include <sys/malloc.h> 74 #include <sys/sysctl.h> 75 76 #include <vm/vm.h> 77 #include <vm/vm_param.h> 78 #include <sys/lock.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/vm_zone.h> 86 87 #include <sys/file2.h> 88 89 #include <machine/cpufunc.h> 90 91 /* 92 * interfaces to the outside world 93 */ 94 static int pipe_read (struct file *fp, struct uio *uio, 95 struct ucred *cred, int flags, struct thread *td); 96 static int pipe_write (struct file *fp, struct uio *uio, 97 struct ucred *cred, int flags, struct thread *td); 98 static int pipe_close (struct file *fp, struct thread *td); 99 static int pipe_poll (struct file *fp, int events, struct ucred *cred, 100 struct thread *td); 101 static int pipe_kqfilter (struct file *fp, struct knote *kn); 102 static int pipe_stat (struct file *fp, struct stat *sb, struct thread *td); 103 static int pipe_ioctl (struct file *fp, u_long cmd, caddr_t data, struct thread *td); 104 105 static struct fileops pipeops = { 106 NULL, /* port */ 107 NULL, /* clone */ 108 pipe_read, pipe_write, pipe_ioctl, pipe_poll, pipe_kqfilter, 109 pipe_stat, pipe_close 110 }; 111 112 static void filt_pipedetach(struct knote *kn); 113 static int filt_piperead(struct knote *kn, long hint); 114 static int filt_pipewrite(struct knote *kn, long hint); 115 116 static struct filterops pipe_rfiltops = 117 { 1, NULL, filt_pipedetach, filt_piperead }; 118 static struct filterops pipe_wfiltops = 119 { 1, NULL, filt_pipedetach, filt_pipewrite }; 120 121 MALLOC_DEFINE(M_PIPE, "pipe", "pipe structures"); 122 123 /* 124 * Default pipe buffer size(s), this can be kind-of large now because pipe 125 * space is pageable. The pipe code will try to maintain locality of 126 * reference for performance reasons, so small amounts of outstanding I/O 127 * will not wipe the cache. 128 */ 129 #define MINPIPESIZE (PIPE_SIZE/3) 130 #define MAXPIPESIZE (2*PIPE_SIZE/3) 131 132 /* 133 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but 134 * is there so that on large systems, we don't exhaust it. 135 */ 136 #define MAXPIPEKVA (8*1024*1024) 137 138 /* 139 * Limit for direct transfers, we cannot, of course limit 140 * the amount of kva for pipes in general though. 141 */ 142 #define LIMITPIPEKVA (16*1024*1024) 143 144 /* 145 * Limit the number of "big" pipes 146 */ 147 #define LIMITBIGPIPES 32 148 #define PIPEQ_MAX_CACHE 16 /* per-cpu pipe structure cache */ 149 150 static int pipe_maxbig = LIMITBIGPIPES; 151 static int pipe_maxcache = PIPEQ_MAX_CACHE; 152 static int pipe_nbig; 153 static int pipe_bcache_alloc; 154 static int pipe_bkmem_alloc; 155 static int pipe_dwrite_enable = 1; /* 0:copy, 1:kmem/sfbuf 2:force */ 156 static int pipe_dwrite_sfbuf = 1; /* 0:kmem_map 1:sfbufs 2:sfbufs_dmap */ 157 /* 3:sfbuf_dmap w/ forced invlpg */ 158 159 SYSCTL_NODE(_kern, OID_AUTO, pipe, CTLFLAG_RW, 0, "Pipe operation"); 160 SYSCTL_INT(_kern_pipe, OID_AUTO, nbig, 161 CTLFLAG_RD, &pipe_nbig, 0, "numer of big pipes allocated"); 162 SYSCTL_INT(_kern_pipe, OID_AUTO, maxcache, 163 CTLFLAG_RW, &pipe_maxcache, 0, "max pipes cached per-cpu"); 164 SYSCTL_INT(_kern_pipe, OID_AUTO, maxbig, 165 CTLFLAG_RW, &pipe_maxbig, 0, "max number of big pipes"); 166 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_enable, 167 CTLFLAG_RW, &pipe_dwrite_enable, 0, "1:enable/2:force direct writes"); 168 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_sfbuf, 169 CTLFLAG_RW, &pipe_dwrite_sfbuf, 0, 170 "(if dwrite_enable) 0:kmem 1:sfbuf 2:sfbuf_dmap 3:sfbuf_dmap_forceinvlpg"); 171 #if !defined(NO_PIPE_SYSCTL_STATS) 172 SYSCTL_INT(_kern_pipe, OID_AUTO, bcache_alloc, 173 CTLFLAG_RW, &pipe_bcache_alloc, 0, "pipe buffer from pcpu cache"); 174 SYSCTL_INT(_kern_pipe, OID_AUTO, bkmem_alloc, 175 CTLFLAG_RW, &pipe_bkmem_alloc, 0, "pipe buffer from kmem"); 176 #endif 177 178 static void pipeclose (struct pipe *cpipe); 179 static void pipe_free_kmem (struct pipe *cpipe); 180 static int pipe_create (struct pipe **cpipep); 181 static __inline int pipelock (struct pipe *cpipe, int catch); 182 static __inline void pipeunlock (struct pipe *cpipe); 183 static __inline void pipeselwakeup (struct pipe *cpipe); 184 #ifndef PIPE_NODIRECT 185 static int pipe_build_write_buffer (struct pipe *wpipe, struct uio *uio); 186 static int pipe_direct_write (struct pipe *wpipe, struct uio *uio); 187 static void pipe_clone_write_buffer (struct pipe *wpipe); 188 #endif 189 static int pipespace (struct pipe *cpipe, int size); 190 191 /* 192 * The pipe system call for the DTYPE_PIPE type of pipes 193 * 194 * pipe_ARgs(int dummy) 195 */ 196 197 /* ARGSUSED */ 198 int 199 pipe(struct pipe_args *uap) 200 { 201 struct thread *td = curthread; 202 struct proc *p = td->td_proc; 203 struct filedesc *fdp; 204 struct file *rf, *wf; 205 struct pipe *rpipe, *wpipe; 206 int fd1, fd2, error; 207 208 KKASSERT(p); 209 fdp = p->p_fd; 210 211 rpipe = wpipe = NULL; 212 if (pipe_create(&rpipe) || pipe_create(&wpipe)) { 213 pipeclose(rpipe); 214 pipeclose(wpipe); 215 return (ENFILE); 216 } 217 218 rpipe->pipe_state |= PIPE_DIRECTOK; 219 wpipe->pipe_state |= PIPE_DIRECTOK; 220 221 /* 222 * Select the direct-map features to use for this pipe. Since the 223 * sysctl's can change on the fly we record the settings when the 224 * pipe is created. 225 * 226 * Generally speaking the system will default to what we consider 227 * to be the best-balanced and most stable option. Right now this 228 * is SFBUF1. Modes 2 and 3 are considered experiemental at the 229 * moment. 230 */ 231 wpipe->pipe_feature = PIPE_COPY; 232 if (pipe_dwrite_enable) { 233 switch(pipe_dwrite_sfbuf) { 234 case 0: 235 wpipe->pipe_feature = PIPE_KMEM; 236 break; 237 case 1: 238 wpipe->pipe_feature = PIPE_SFBUF1; 239 break; 240 case 2: 241 case 3: 242 wpipe->pipe_feature = PIPE_SFBUF2; 243 break; 244 } 245 } 246 rpipe->pipe_feature = wpipe->pipe_feature; 247 248 error = falloc(p, &rf, &fd1); 249 if (error) { 250 pipeclose(rpipe); 251 pipeclose(wpipe); 252 return (error); 253 } 254 uap->sysmsg_fds[0] = fd1; 255 256 /* 257 * Warning: once we've gotten past allocation of the fd for the 258 * read-side, we can only drop the read side via fdrop() in order 259 * to avoid races against processes which manage to dup() the read 260 * side while we are blocked trying to allocate the write side. 261 */ 262 rf->f_flag = FREAD | FWRITE; 263 rf->f_type = DTYPE_PIPE; 264 rf->f_data = (caddr_t)rpipe; 265 rf->f_ops = &pipeops; 266 error = falloc(p, &wf, &fd2); 267 if (error) { 268 if (fdp->fd_ofiles[fd1] == rf) { 269 fdp->fd_ofiles[fd1] = NULL; 270 fdrop(rf, td); 271 } 272 fdrop(rf, td); 273 /* rpipe has been closed by fdrop(). */ 274 pipeclose(wpipe); 275 return (error); 276 } 277 wf->f_flag = FREAD | FWRITE; 278 wf->f_type = DTYPE_PIPE; 279 wf->f_data = (caddr_t)wpipe; 280 wf->f_ops = &pipeops; 281 uap->sysmsg_fds[1] = fd2; 282 283 rpipe->pipe_peer = wpipe; 284 wpipe->pipe_peer = rpipe; 285 fdrop(rf, td); 286 fdrop(wf, td); 287 288 return (0); 289 } 290 291 /* 292 * Allocate kva for pipe circular buffer, the space is pageable 293 * This routine will 'realloc' the size of a pipe safely, if it fails 294 * it will retain the old buffer. 295 * If it fails it will return ENOMEM. 296 */ 297 static int 298 pipespace(struct pipe *cpipe, int size) 299 { 300 struct vm_object *object; 301 caddr_t buffer; 302 int npages, error; 303 304 npages = round_page(size) / PAGE_SIZE; 305 object = cpipe->pipe_buffer.object; 306 307 /* 308 * [re]create the object if necessary and reserve space for it 309 * in the kernel_map. The object and memory are pageable. On 310 * success, free the old resources before assigning the new 311 * ones. 312 */ 313 if (object == NULL || object->size != npages) { 314 object = vm_object_allocate(OBJT_DEFAULT, npages); 315 buffer = (caddr_t) vm_map_min(kernel_map); 316 317 error = vm_map_find(kernel_map, object, 0, 318 (vm_offset_t *) &buffer, size, 1, 319 VM_PROT_ALL, VM_PROT_ALL, 0); 320 321 if (error != KERN_SUCCESS) { 322 vm_object_deallocate(object); 323 return (ENOMEM); 324 } 325 pipe_free_kmem(cpipe); 326 cpipe->pipe_buffer.object = object; 327 cpipe->pipe_buffer.buffer = buffer; 328 cpipe->pipe_buffer.size = size; 329 ++pipe_bkmem_alloc; 330 } else { 331 ++pipe_bcache_alloc; 332 } 333 cpipe->pipe_buffer.in = 0; 334 cpipe->pipe_buffer.out = 0; 335 cpipe->pipe_buffer.cnt = 0; 336 return (0); 337 } 338 339 /* 340 * Initialize and allocate VM and memory for pipe, pulling the pipe from 341 * our per-cpu cache if possible. For now make sure it is sized for the 342 * smaller PIPE_SIZE default. 343 */ 344 static int 345 pipe_create(cpipep) 346 struct pipe **cpipep; 347 { 348 globaldata_t gd = mycpu; 349 struct pipe *cpipe; 350 int error; 351 352 if ((cpipe = gd->gd_pipeq) != NULL) { 353 gd->gd_pipeq = cpipe->pipe_peer; 354 --gd->gd_pipeqcount; 355 cpipe->pipe_peer = NULL; 356 } else { 357 cpipe = malloc(sizeof(struct pipe), M_PIPE, M_WAITOK|M_ZERO); 358 } 359 *cpipep = cpipe; 360 if ((error = pipespace(cpipe, PIPE_SIZE)) != 0) 361 return (error); 362 vfs_timestamp(&cpipe->pipe_ctime); 363 cpipe->pipe_atime = cpipe->pipe_ctime; 364 cpipe->pipe_mtime = cpipe->pipe_ctime; 365 return (0); 366 } 367 368 369 /* 370 * lock a pipe for I/O, blocking other access 371 */ 372 static __inline int 373 pipelock(cpipe, catch) 374 struct pipe *cpipe; 375 int catch; 376 { 377 int error; 378 379 while (cpipe->pipe_state & PIPE_LOCK) { 380 cpipe->pipe_state |= PIPE_LWANT; 381 error = tsleep(cpipe, (catch ? PCATCH : 0), "pipelk", 0); 382 if (error != 0) 383 return (error); 384 } 385 cpipe->pipe_state |= PIPE_LOCK; 386 return (0); 387 } 388 389 /* 390 * unlock a pipe I/O lock 391 */ 392 static __inline void 393 pipeunlock(cpipe) 394 struct pipe *cpipe; 395 { 396 397 cpipe->pipe_state &= ~PIPE_LOCK; 398 if (cpipe->pipe_state & PIPE_LWANT) { 399 cpipe->pipe_state &= ~PIPE_LWANT; 400 wakeup(cpipe); 401 } 402 } 403 404 static __inline void 405 pipeselwakeup(cpipe) 406 struct pipe *cpipe; 407 { 408 409 if (cpipe->pipe_state & PIPE_SEL) { 410 cpipe->pipe_state &= ~PIPE_SEL; 411 selwakeup(&cpipe->pipe_sel); 412 } 413 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) 414 pgsigio(cpipe->pipe_sigio, SIGIO, 0); 415 KNOTE(&cpipe->pipe_sel.si_note, 0); 416 } 417 418 /* ARGSUSED */ 419 static int 420 pipe_read(struct file *fp, struct uio *uio, struct ucred *cred, 421 int flags, struct thread *td) 422 { 423 struct pipe *rpipe = (struct pipe *) fp->f_data; 424 int error; 425 int nread = 0; 426 u_int size; 427 428 ++rpipe->pipe_busy; 429 error = pipelock(rpipe, 1); 430 if (error) 431 goto unlocked_error; 432 433 while (uio->uio_resid) { 434 caddr_t va; 435 436 if (rpipe->pipe_buffer.cnt > 0) { 437 /* 438 * normal pipe buffer receive 439 */ 440 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 441 if (size > rpipe->pipe_buffer.cnt) 442 size = rpipe->pipe_buffer.cnt; 443 if (size > (u_int) uio->uio_resid) 444 size = (u_int) uio->uio_resid; 445 446 error = uiomove(&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 447 size, uio); 448 if (error) 449 break; 450 451 rpipe->pipe_buffer.out += size; 452 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 453 rpipe->pipe_buffer.out = 0; 454 455 rpipe->pipe_buffer.cnt -= size; 456 457 /* 458 * If there is no more to read in the pipe, reset 459 * its pointers to the beginning. This improves 460 * cache hit stats. 461 */ 462 if (rpipe->pipe_buffer.cnt == 0) { 463 rpipe->pipe_buffer.in = 0; 464 rpipe->pipe_buffer.out = 0; 465 } 466 nread += size; 467 #ifndef PIPE_NODIRECT 468 } else if (rpipe->pipe_kva && 469 rpipe->pipe_feature == PIPE_KMEM && 470 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 471 == PIPE_DIRECTW 472 ) { 473 /* 474 * Direct copy using source-side kva mapping 475 */ 476 size = rpipe->pipe_map.xio_bytes; 477 if (size > (u_int)uio->uio_resid) 478 size = (u_int)uio->uio_resid; 479 va = (caddr_t)rpipe->pipe_kva + rpipe->pipe_map.xio_offset; 480 error = uiomove(va, size, uio); 481 if (error) 482 break; 483 nread += size; 484 rpipe->pipe_map.xio_offset += size; 485 rpipe->pipe_map.xio_bytes -= size; 486 if (rpipe->pipe_map.xio_bytes == 0) { 487 rpipe->pipe_state |= PIPE_DIRECTIP; 488 rpipe->pipe_state &= ~PIPE_DIRECTW; 489 wakeup(rpipe); 490 } 491 } else if (rpipe->pipe_map.xio_bytes && 492 rpipe->pipe_kva && 493 rpipe->pipe_feature == PIPE_SFBUF2 && 494 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 495 == PIPE_DIRECTW 496 ) { 497 /* 498 * Direct copy, bypassing a kernel buffer. We cannot 499 * mess with the direct-write buffer until 500 * PIPE_DIRECTIP is cleared. In order to prevent 501 * the pipe_write code from racing itself in 502 * direct_write, we set DIRECTIP when we clear 503 * DIRECTW after we have exhausted the buffer. 504 */ 505 if (pipe_dwrite_sfbuf == 3) 506 rpipe->pipe_kvamask = 0; 507 pmap_qenter2(rpipe->pipe_kva, rpipe->pipe_map.xio_pages, 508 rpipe->pipe_map.xio_npages, 509 &rpipe->pipe_kvamask); 510 size = rpipe->pipe_map.xio_bytes; 511 if (size > (u_int)uio->uio_resid) 512 size = (u_int)uio->uio_resid; 513 va = (caddr_t)rpipe->pipe_kva + 514 rpipe->pipe_map.xio_offset; 515 error = uiomove(va, size, uio); 516 if (error) 517 break; 518 nread += size; 519 rpipe->pipe_map.xio_offset += size; 520 rpipe->pipe_map.xio_bytes -= size; 521 if (rpipe->pipe_map.xio_bytes == 0) { 522 rpipe->pipe_state |= PIPE_DIRECTIP; 523 rpipe->pipe_state &= ~PIPE_DIRECTW; 524 wakeup(rpipe); 525 } 526 } else if (rpipe->pipe_map.xio_bytes && 527 rpipe->pipe_feature == PIPE_SFBUF1 && 528 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 529 == PIPE_DIRECTW 530 ) { 531 /* 532 * Direct copy, bypassing a kernel buffer. We cannot 533 * mess with the direct-write buffer until 534 * PIPE_DIRECTIP is cleared. In order to prevent 535 * the pipe_write code from racing itself in 536 * direct_write, we set DIRECTIP when we clear 537 * DIRECTW after we have exhausted the buffer. 538 */ 539 error = xio_uio_copy(&rpipe->pipe_map, uio, &size); 540 if (error) 541 break; 542 nread += size; 543 if (rpipe->pipe_map.xio_bytes == 0) { 544 rpipe->pipe_state |= PIPE_DIRECTIP; 545 rpipe->pipe_state &= ~PIPE_DIRECTW; 546 wakeup(rpipe); 547 } 548 #endif 549 } else { 550 /* 551 * detect EOF condition 552 * read returns 0 on EOF, no need to set error 553 */ 554 if (rpipe->pipe_state & PIPE_EOF) 555 break; 556 557 /* 558 * If the "write-side" has been blocked, wake it up now. 559 */ 560 if (rpipe->pipe_state & PIPE_WANTW) { 561 rpipe->pipe_state &= ~PIPE_WANTW; 562 wakeup(rpipe); 563 } 564 565 /* 566 * Break if some data was read. 567 */ 568 if (nread > 0) 569 break; 570 571 /* 572 * Unlock the pipe buffer for our remaining 573 * processing. We will either break out with an 574 * error or we will sleep and relock to loop. 575 */ 576 pipeunlock(rpipe); 577 578 /* 579 * Handle non-blocking mode operation or 580 * wait for more data. 581 */ 582 if (fp->f_flag & FNONBLOCK) { 583 error = EAGAIN; 584 } else { 585 rpipe->pipe_state |= PIPE_WANTR; 586 if ((error = tsleep(rpipe, PCATCH|PNORESCHED, 587 "piperd", 0)) == 0) { 588 error = pipelock(rpipe, 1); 589 } 590 } 591 if (error) 592 goto unlocked_error; 593 } 594 } 595 pipeunlock(rpipe); 596 597 if (error == 0) 598 vfs_timestamp(&rpipe->pipe_atime); 599 unlocked_error: 600 --rpipe->pipe_busy; 601 602 /* 603 * PIPE_WANT processing only makes sense if pipe_busy is 0. 604 */ 605 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 606 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 607 wakeup(rpipe); 608 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 609 /* 610 * Handle write blocking hysteresis. 611 */ 612 if (rpipe->pipe_state & PIPE_WANTW) { 613 rpipe->pipe_state &= ~PIPE_WANTW; 614 wakeup(rpipe); 615 } 616 } 617 618 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 619 pipeselwakeup(rpipe); 620 return (error); 621 } 622 623 #ifndef PIPE_NODIRECT 624 /* 625 * Map the sending processes' buffer into kernel space and wire it. 626 * This is similar to a physical write operation. 627 */ 628 static int 629 pipe_build_write_buffer(wpipe, uio) 630 struct pipe *wpipe; 631 struct uio *uio; 632 { 633 int error; 634 u_int size; 635 636 size = (u_int) uio->uio_iov->iov_len; 637 if (size > wpipe->pipe_buffer.size) 638 size = wpipe->pipe_buffer.size; 639 640 error = xio_init_ubuf(&wpipe->pipe_map, uio->uio_iov->iov_base, 641 size, XIOF_READ); 642 if (error) 643 return(error); 644 645 /* 646 * Create a kernel map for KMEM and SFBUF2 copy modes. SFBUF2 will 647 * map the pages on the target while KMEM maps the pages now. 648 */ 649 switch(wpipe->pipe_feature) { 650 case PIPE_KMEM: 651 case PIPE_SFBUF2: 652 if (wpipe->pipe_kva == NULL) { 653 wpipe->pipe_kva = 654 kmem_alloc_nofault(kernel_map, XIO_INTERNAL_SIZE); 655 wpipe->pipe_kvamask = 0; 656 } 657 if (wpipe->pipe_feature == PIPE_KMEM) { 658 pmap_qenter(wpipe->pipe_kva, wpipe->pipe_map.xio_pages, 659 wpipe->pipe_map.xio_npages); 660 } 661 break; 662 default: 663 break; 664 } 665 666 /* 667 * And update the uio data. The XIO might have loaded fewer bytes 668 * then requested so reload 'size'. 669 */ 670 size = wpipe->pipe_map.xio_bytes; 671 uio->uio_iov->iov_len -= size; 672 uio->uio_iov->iov_base += size; 673 if (uio->uio_iov->iov_len == 0) 674 uio->uio_iov++; 675 uio->uio_resid -= size; 676 uio->uio_offset += size; 677 return (0); 678 } 679 680 /* 681 * In the case of a signal, the writing process might go away. This 682 * code copies the data into the circular buffer so that the source 683 * pages can be freed without loss of data. 684 */ 685 static void 686 pipe_clone_write_buffer(wpipe) 687 struct pipe *wpipe; 688 { 689 int size; 690 691 size = wpipe->pipe_map.xio_bytes; 692 693 KKASSERT(size <= wpipe->pipe_buffer.size); 694 695 wpipe->pipe_buffer.in = size; 696 wpipe->pipe_buffer.out = 0; 697 wpipe->pipe_buffer.cnt = size; 698 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP); 699 700 xio_copy_xtok(&wpipe->pipe_map, wpipe->pipe_buffer.buffer, size); 701 xio_release(&wpipe->pipe_map); 702 if (wpipe->pipe_kva) { 703 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES); 704 kmem_free(kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE); 705 wpipe->pipe_kva = NULL; 706 } 707 } 708 709 /* 710 * This implements the pipe buffer write mechanism. Note that only 711 * a direct write OR a normal pipe write can be pending at any given time. 712 * If there are any characters in the pipe buffer, the direct write will 713 * be deferred until the receiving process grabs all of the bytes from 714 * the pipe buffer. Then the direct mapping write is set-up. 715 */ 716 static int 717 pipe_direct_write(wpipe, uio) 718 struct pipe *wpipe; 719 struct uio *uio; 720 { 721 int error; 722 723 retry: 724 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 725 if (wpipe->pipe_state & PIPE_WANTR) { 726 wpipe->pipe_state &= ~PIPE_WANTR; 727 wakeup(wpipe); 728 } 729 wpipe->pipe_state |= PIPE_WANTW; 730 error = tsleep(wpipe, PCATCH, "pipdww", 0); 731 if (error) 732 goto error2; 733 if (wpipe->pipe_state & PIPE_EOF) { 734 error = EPIPE; 735 goto error2; 736 } 737 } 738 KKASSERT(wpipe->pipe_map.xio_bytes == 0); 739 if (wpipe->pipe_buffer.cnt > 0) { 740 if (wpipe->pipe_state & PIPE_WANTR) { 741 wpipe->pipe_state &= ~PIPE_WANTR; 742 wakeup(wpipe); 743 } 744 745 wpipe->pipe_state |= PIPE_WANTW; 746 error = tsleep(wpipe, PCATCH, "pipdwc", 0); 747 if (error) 748 goto error2; 749 if (wpipe->pipe_state & PIPE_EOF) { 750 error = EPIPE; 751 goto error2; 752 } 753 goto retry; 754 } 755 756 /* 757 * Build our direct-write buffer 758 */ 759 wpipe->pipe_state |= PIPE_DIRECTW | PIPE_DIRECTIP; 760 error = pipe_build_write_buffer(wpipe, uio); 761 if (error) 762 goto error1; 763 wpipe->pipe_state &= ~PIPE_DIRECTIP; 764 765 /* 766 * Wait until the receiver has snarfed the data. Since we are likely 767 * going to sleep we optimize the case and yield synchronously, 768 * possibly avoiding the tsleep(). 769 */ 770 error = 0; 771 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 772 if (wpipe->pipe_state & PIPE_EOF) { 773 pipelock(wpipe, 0); 774 xio_release(&wpipe->pipe_map); 775 if (wpipe->pipe_kva) { 776 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES); 777 kmem_free(kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE); 778 wpipe->pipe_kva = NULL; 779 } 780 pipeunlock(wpipe); 781 pipeselwakeup(wpipe); 782 error = EPIPE; 783 goto error1; 784 } 785 if (wpipe->pipe_state & PIPE_WANTR) { 786 wpipe->pipe_state &= ~PIPE_WANTR; 787 wakeup(wpipe); 788 } 789 pipeselwakeup(wpipe); 790 error = tsleep(wpipe, PCATCH|PNORESCHED, "pipdwt", 0); 791 } 792 pipelock(wpipe,0); 793 if (wpipe->pipe_state & PIPE_DIRECTW) { 794 /* 795 * this bit of trickery substitutes a kernel buffer for 796 * the process that might be going away. 797 */ 798 pipe_clone_write_buffer(wpipe); 799 KKASSERT((wpipe->pipe_state & PIPE_DIRECTIP) == 0); 800 } else { 801 /* 802 * note: The pipe_kva mapping is not qremove'd here. For 803 * legacy PIPE_KMEM mode this constitutes an improvement 804 * over the original FreeBSD-4 algorithm. For PIPE_SFBUF2 805 * mode the kva mapping must not be removed to get the 806 * caching benefit. 807 * 808 * For testing purposes we will give the original algorithm 809 * the benefit of the doubt 'what it could have been', and 810 * keep the optimization. 811 */ 812 KKASSERT(wpipe->pipe_state & PIPE_DIRECTIP); 813 xio_release(&wpipe->pipe_map); 814 wpipe->pipe_state &= ~PIPE_DIRECTIP; 815 } 816 pipeunlock(wpipe); 817 return (error); 818 819 /* 820 * Direct-write error, clear the direct write flags. 821 */ 822 error1: 823 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP); 824 /* fallthrough */ 825 826 /* 827 * General error, wakeup the other side if it happens to be sleeping. 828 */ 829 error2: 830 wakeup(wpipe); 831 return (error); 832 } 833 #endif 834 835 static int 836 pipe_write(struct file *fp, struct uio *uio, struct ucred *cred, 837 int flags, struct thread *td) 838 { 839 int error = 0; 840 int orig_resid; 841 struct pipe *wpipe, *rpipe; 842 843 rpipe = (struct pipe *) fp->f_data; 844 wpipe = rpipe->pipe_peer; 845 846 /* 847 * detect loss of pipe read side, issue SIGPIPE if lost. 848 */ 849 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 850 return (EPIPE); 851 } 852 ++wpipe->pipe_busy; 853 854 /* 855 * If it is advantageous to resize the pipe buffer, do 856 * so. 857 */ 858 if ((uio->uio_resid > PIPE_SIZE) && 859 (pipe_nbig < pipe_maxbig) && 860 (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) == 0 && 861 (wpipe->pipe_buffer.size <= PIPE_SIZE) && 862 (wpipe->pipe_buffer.cnt == 0)) { 863 864 if ((error = pipelock(wpipe,1)) == 0) { 865 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 866 pipe_nbig++; 867 pipeunlock(wpipe); 868 } 869 } 870 871 /* 872 * If an early error occured unbusy and return, waking up any pending 873 * readers. 874 */ 875 if (error) { 876 --wpipe->pipe_busy; 877 if ((wpipe->pipe_busy == 0) && 878 (wpipe->pipe_state & PIPE_WANT)) { 879 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 880 wakeup(wpipe); 881 } 882 return(error); 883 } 884 885 KASSERT(wpipe->pipe_buffer.buffer != NULL, ("pipe buffer gone")); 886 887 orig_resid = uio->uio_resid; 888 889 while (uio->uio_resid) { 890 int space; 891 892 #ifndef PIPE_NODIRECT 893 /* 894 * If the transfer is large, we can gain performance if 895 * we do process-to-process copies directly. 896 * If the write is non-blocking, we don't use the 897 * direct write mechanism. 898 * 899 * The direct write mechanism will detect the reader going 900 * away on us. 901 */ 902 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT || 903 pipe_dwrite_enable > 1) && 904 (fp->f_flag & FNONBLOCK) == 0 && 905 pipe_dwrite_enable) { 906 error = pipe_direct_write( wpipe, uio); 907 if (error) 908 break; 909 continue; 910 } 911 #endif 912 913 /* 914 * Pipe buffered writes cannot be coincidental with 915 * direct writes. We wait until the currently executing 916 * direct write is completed before we start filling the 917 * pipe buffer. We break out if a signal occurs or the 918 * reader goes away. 919 */ 920 retrywrite: 921 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 922 if (wpipe->pipe_state & PIPE_WANTR) { 923 wpipe->pipe_state &= ~PIPE_WANTR; 924 wakeup(wpipe); 925 } 926 error = tsleep(wpipe, PCATCH, "pipbww", 0); 927 if (wpipe->pipe_state & PIPE_EOF) 928 break; 929 if (error) 930 break; 931 } 932 if (wpipe->pipe_state & PIPE_EOF) { 933 error = EPIPE; 934 break; 935 } 936 937 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 938 939 /* Writes of size <= PIPE_BUF must be atomic. */ 940 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 941 space = 0; 942 943 /* 944 * Write to fill, read size handles write hysteresis. Also 945 * additional restrictions can cause select-based non-blocking 946 * writes to spin. 947 */ 948 if (space > 0) { 949 if ((error = pipelock(wpipe,1)) == 0) { 950 int size; /* Transfer size */ 951 int segsize; /* first segment to transfer */ 952 953 /* 954 * It is possible for a direct write to 955 * slip in on us... handle it here... 956 */ 957 if (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 958 pipeunlock(wpipe); 959 goto retrywrite; 960 } 961 /* 962 * If a process blocked in uiomove, our 963 * value for space might be bad. 964 * 965 * XXX will we be ok if the reader has gone 966 * away here? 967 */ 968 if (space > wpipe->pipe_buffer.size - 969 wpipe->pipe_buffer.cnt) { 970 pipeunlock(wpipe); 971 goto retrywrite; 972 } 973 974 /* 975 * Transfer size is minimum of uio transfer 976 * and free space in pipe buffer. 977 */ 978 if (space > uio->uio_resid) 979 size = uio->uio_resid; 980 else 981 size = space; 982 /* 983 * First segment to transfer is minimum of 984 * transfer size and contiguous space in 985 * pipe buffer. If first segment to transfer 986 * is less than the transfer size, we've got 987 * a wraparound in the buffer. 988 */ 989 segsize = wpipe->pipe_buffer.size - 990 wpipe->pipe_buffer.in; 991 if (segsize > size) 992 segsize = size; 993 994 /* Transfer first segment */ 995 996 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 997 segsize, uio); 998 999 if (error == 0 && segsize < size) { 1000 /* 1001 * Transfer remaining part now, to 1002 * support atomic writes. Wraparound 1003 * happened. 1004 */ 1005 if (wpipe->pipe_buffer.in + segsize != 1006 wpipe->pipe_buffer.size) 1007 panic("Expected pipe buffer wraparound disappeared"); 1008 1009 error = uiomove(&wpipe->pipe_buffer.buffer[0], 1010 size - segsize, uio); 1011 } 1012 if (error == 0) { 1013 wpipe->pipe_buffer.in += size; 1014 if (wpipe->pipe_buffer.in >= 1015 wpipe->pipe_buffer.size) { 1016 if (wpipe->pipe_buffer.in != size - segsize + wpipe->pipe_buffer.size) 1017 panic("Expected wraparound bad"); 1018 wpipe->pipe_buffer.in = size - segsize; 1019 } 1020 1021 wpipe->pipe_buffer.cnt += size; 1022 if (wpipe->pipe_buffer.cnt > wpipe->pipe_buffer.size) 1023 panic("Pipe buffer overflow"); 1024 1025 } 1026 pipeunlock(wpipe); 1027 } 1028 if (error) 1029 break; 1030 1031 } else { 1032 /* 1033 * If the "read-side" has been blocked, wake it up now 1034 * and yield to let it drain synchronously rather 1035 * then block. 1036 */ 1037 if (wpipe->pipe_state & PIPE_WANTR) { 1038 wpipe->pipe_state &= ~PIPE_WANTR; 1039 wakeup(wpipe); 1040 } 1041 1042 /* 1043 * don't block on non-blocking I/O 1044 */ 1045 if (fp->f_flag & FNONBLOCK) { 1046 error = EAGAIN; 1047 break; 1048 } 1049 1050 /* 1051 * We have no more space and have something to offer, 1052 * wake up select/poll. 1053 */ 1054 pipeselwakeup(wpipe); 1055 1056 wpipe->pipe_state |= PIPE_WANTW; 1057 error = tsleep(wpipe, PCATCH|PNORESCHED, "pipewr", 0); 1058 if (error != 0) 1059 break; 1060 /* 1061 * If read side wants to go away, we just issue a signal 1062 * to ourselves. 1063 */ 1064 if (wpipe->pipe_state & PIPE_EOF) { 1065 error = EPIPE; 1066 break; 1067 } 1068 } 1069 } 1070 1071 --wpipe->pipe_busy; 1072 1073 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1074 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1075 wakeup(wpipe); 1076 } else if (wpipe->pipe_buffer.cnt > 0) { 1077 /* 1078 * If we have put any characters in the buffer, we wake up 1079 * the reader. 1080 */ 1081 if (wpipe->pipe_state & PIPE_WANTR) { 1082 wpipe->pipe_state &= ~PIPE_WANTR; 1083 wakeup(wpipe); 1084 } 1085 } 1086 1087 /* 1088 * Don't return EPIPE if I/O was successful 1089 */ 1090 if ((wpipe->pipe_buffer.cnt == 0) && 1091 (uio->uio_resid == 0) && 1092 (error == EPIPE)) { 1093 error = 0; 1094 } 1095 1096 if (error == 0) 1097 vfs_timestamp(&wpipe->pipe_mtime); 1098 1099 /* 1100 * We have something to offer, 1101 * wake up select/poll. 1102 */ 1103 if (wpipe->pipe_buffer.cnt) 1104 pipeselwakeup(wpipe); 1105 1106 return (error); 1107 } 1108 1109 /* 1110 * we implement a very minimal set of ioctls for compatibility with sockets. 1111 */ 1112 int 1113 pipe_ioctl(struct file *fp, u_long cmd, caddr_t data, struct thread *td) 1114 { 1115 struct pipe *mpipe = (struct pipe *)fp->f_data; 1116 1117 switch (cmd) { 1118 1119 case FIONBIO: 1120 return (0); 1121 1122 case FIOASYNC: 1123 if (*(int *)data) { 1124 mpipe->pipe_state |= PIPE_ASYNC; 1125 } else { 1126 mpipe->pipe_state &= ~PIPE_ASYNC; 1127 } 1128 return (0); 1129 1130 case FIONREAD: 1131 if (mpipe->pipe_state & PIPE_DIRECTW) { 1132 *(int *)data = mpipe->pipe_map.xio_bytes; 1133 } else { 1134 *(int *)data = mpipe->pipe_buffer.cnt; 1135 } 1136 return (0); 1137 1138 case FIOSETOWN: 1139 return (fsetown(*(int *)data, &mpipe->pipe_sigio)); 1140 1141 case FIOGETOWN: 1142 *(int *)data = fgetown(mpipe->pipe_sigio); 1143 return (0); 1144 1145 /* This is deprecated, FIOSETOWN should be used instead. */ 1146 case TIOCSPGRP: 1147 return (fsetown(-(*(int *)data), &mpipe->pipe_sigio)); 1148 1149 /* This is deprecated, FIOGETOWN should be used instead. */ 1150 case TIOCGPGRP: 1151 *(int *)data = -fgetown(mpipe->pipe_sigio); 1152 return (0); 1153 1154 } 1155 return (ENOTTY); 1156 } 1157 1158 int 1159 pipe_poll(struct file *fp, int events, struct ucred *cred, struct thread *td) 1160 { 1161 struct pipe *rpipe = (struct pipe *)fp->f_data; 1162 struct pipe *wpipe; 1163 int revents = 0; 1164 1165 wpipe = rpipe->pipe_peer; 1166 if (events & (POLLIN | POLLRDNORM)) 1167 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1168 (rpipe->pipe_buffer.cnt > 0) || 1169 (rpipe->pipe_state & PIPE_EOF)) 1170 revents |= events & (POLLIN | POLLRDNORM); 1171 1172 if (events & (POLLOUT | POLLWRNORM)) 1173 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) || 1174 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1175 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1176 revents |= events & (POLLOUT | POLLWRNORM); 1177 1178 if ((rpipe->pipe_state & PIPE_EOF) || 1179 (wpipe == NULL) || 1180 (wpipe->pipe_state & PIPE_EOF)) 1181 revents |= POLLHUP; 1182 1183 if (revents == 0) { 1184 if (events & (POLLIN | POLLRDNORM)) { 1185 selrecord(td, &rpipe->pipe_sel); 1186 rpipe->pipe_state |= PIPE_SEL; 1187 } 1188 1189 if (events & (POLLOUT | POLLWRNORM)) { 1190 selrecord(td, &wpipe->pipe_sel); 1191 wpipe->pipe_state |= PIPE_SEL; 1192 } 1193 } 1194 1195 return (revents); 1196 } 1197 1198 static int 1199 pipe_stat(struct file *fp, struct stat *ub, struct thread *td) 1200 { 1201 struct pipe *pipe = (struct pipe *)fp->f_data; 1202 1203 bzero((caddr_t)ub, sizeof(*ub)); 1204 ub->st_mode = S_IFIFO; 1205 ub->st_blksize = pipe->pipe_buffer.size; 1206 ub->st_size = pipe->pipe_buffer.cnt; 1207 if (ub->st_size == 0 && (pipe->pipe_state & PIPE_DIRECTW)) 1208 ub->st_size = pipe->pipe_map.xio_bytes; 1209 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1210 ub->st_atimespec = pipe->pipe_atime; 1211 ub->st_mtimespec = pipe->pipe_mtime; 1212 ub->st_ctimespec = pipe->pipe_ctime; 1213 /* 1214 * Left as 0: st_dev, st_ino, st_nlink, st_uid, st_gid, st_rdev, 1215 * st_flags, st_gen. 1216 * XXX (st_dev, st_ino) should be unique. 1217 */ 1218 return (0); 1219 } 1220 1221 /* ARGSUSED */ 1222 static int 1223 pipe_close(struct file *fp, struct thread *td) 1224 { 1225 struct pipe *cpipe = (struct pipe *)fp->f_data; 1226 1227 fp->f_ops = &badfileops; 1228 fp->f_data = NULL; 1229 funsetown(cpipe->pipe_sigio); 1230 pipeclose(cpipe); 1231 return (0); 1232 } 1233 1234 static void 1235 pipe_free_kmem(struct pipe *cpipe) 1236 { 1237 if (cpipe->pipe_buffer.buffer != NULL) { 1238 if (cpipe->pipe_buffer.size > PIPE_SIZE) 1239 --pipe_nbig; 1240 kmem_free(kernel_map, 1241 (vm_offset_t)cpipe->pipe_buffer.buffer, 1242 cpipe->pipe_buffer.size); 1243 cpipe->pipe_buffer.buffer = NULL; 1244 cpipe->pipe_buffer.object = NULL; 1245 } 1246 #ifndef PIPE_NODIRECT 1247 KKASSERT(cpipe->pipe_map.xio_bytes == 0 && 1248 cpipe->pipe_map.xio_offset == 0 && 1249 cpipe->pipe_map.xio_npages == 0); 1250 #endif 1251 } 1252 1253 /* 1254 * shutdown the pipe 1255 */ 1256 static void 1257 pipeclose(struct pipe *cpipe) 1258 { 1259 globaldata_t gd; 1260 struct pipe *ppipe; 1261 1262 if (cpipe == NULL) 1263 return; 1264 1265 pipeselwakeup(cpipe); 1266 1267 /* 1268 * If the other side is blocked, wake it up saying that 1269 * we want to close it down. 1270 */ 1271 while (cpipe->pipe_busy) { 1272 wakeup(cpipe); 1273 cpipe->pipe_state |= PIPE_WANT | PIPE_EOF; 1274 tsleep(cpipe, 0, "pipecl", 0); 1275 } 1276 1277 /* 1278 * Disconnect from peer 1279 */ 1280 if ((ppipe = cpipe->pipe_peer) != NULL) { 1281 pipeselwakeup(ppipe); 1282 1283 ppipe->pipe_state |= PIPE_EOF; 1284 wakeup(ppipe); 1285 KNOTE(&ppipe->pipe_sel.si_note, 0); 1286 ppipe->pipe_peer = NULL; 1287 } 1288 1289 if (cpipe->pipe_kva) { 1290 pmap_qremove(cpipe->pipe_kva, XIO_INTERNAL_PAGES); 1291 kmem_free(kernel_map, cpipe->pipe_kva, XIO_INTERNAL_SIZE); 1292 cpipe->pipe_kva = NULL; 1293 } 1294 1295 /* 1296 * free or cache resources 1297 */ 1298 gd = mycpu; 1299 if (gd->gd_pipeqcount >= pipe_maxcache || 1300 cpipe->pipe_buffer.size != PIPE_SIZE 1301 ) { 1302 pipe_free_kmem(cpipe); 1303 free(cpipe, M_PIPE); 1304 } else { 1305 KKASSERT(cpipe->pipe_map.xio_npages == 0 && 1306 cpipe->pipe_map.xio_bytes == 0 && 1307 cpipe->pipe_map.xio_offset == 0); 1308 cpipe->pipe_state = 0; 1309 cpipe->pipe_busy = 0; 1310 cpipe->pipe_peer = gd->gd_pipeq; 1311 gd->gd_pipeq = cpipe; 1312 ++gd->gd_pipeqcount; 1313 } 1314 } 1315 1316 /*ARGSUSED*/ 1317 static int 1318 pipe_kqfilter(struct file *fp, struct knote *kn) 1319 { 1320 struct pipe *cpipe = (struct pipe *)kn->kn_fp->f_data; 1321 1322 switch (kn->kn_filter) { 1323 case EVFILT_READ: 1324 kn->kn_fop = &pipe_rfiltops; 1325 break; 1326 case EVFILT_WRITE: 1327 kn->kn_fop = &pipe_wfiltops; 1328 cpipe = cpipe->pipe_peer; 1329 if (cpipe == NULL) 1330 /* other end of pipe has been closed */ 1331 return (EPIPE); 1332 break; 1333 default: 1334 return (1); 1335 } 1336 kn->kn_hook = (caddr_t)cpipe; 1337 1338 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext); 1339 return (0); 1340 } 1341 1342 static void 1343 filt_pipedetach(struct knote *kn) 1344 { 1345 struct pipe *cpipe = (struct pipe *)kn->kn_hook; 1346 1347 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext); 1348 } 1349 1350 /*ARGSUSED*/ 1351 static int 1352 filt_piperead(struct knote *kn, long hint) 1353 { 1354 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1355 struct pipe *wpipe = rpipe->pipe_peer; 1356 1357 kn->kn_data = rpipe->pipe_buffer.cnt; 1358 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1359 kn->kn_data = rpipe->pipe_map.xio_bytes; 1360 1361 if ((rpipe->pipe_state & PIPE_EOF) || 1362 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1363 kn->kn_flags |= EV_EOF; 1364 return (1); 1365 } 1366 return (kn->kn_data > 0); 1367 } 1368 1369 /*ARGSUSED*/ 1370 static int 1371 filt_pipewrite(struct knote *kn, long hint) 1372 { 1373 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1374 struct pipe *wpipe = rpipe->pipe_peer; 1375 1376 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1377 kn->kn_data = 0; 1378 kn->kn_flags |= EV_EOF; 1379 return (1); 1380 } 1381 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1382 if (wpipe->pipe_state & PIPE_DIRECTW) 1383 kn->kn_data = 0; 1384 1385 return (kn->kn_data >= PIPE_BUF); 1386 } 1387