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 1.32 2005/09/02 07:16:58 hsu 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 #include <sys/socket.h> 76 77 #include <vm/vm.h> 78 #include <vm/vm_param.h> 79 #include <sys/lock.h> 80 #include <vm/vm_object.h> 81 #include <vm/vm_kern.h> 82 #include <vm/vm_extern.h> 83 #include <vm/pmap.h> 84 #include <vm/vm_map.h> 85 #include <vm/vm_page.h> 86 #include <vm/vm_zone.h> 87 88 #include <sys/file2.h> 89 90 #include <machine/cpufunc.h> 91 92 /* 93 * interfaces to the outside world 94 */ 95 static int pipe_read (struct file *fp, struct uio *uio, 96 struct ucred *cred, int flags, struct thread *td); 97 static int pipe_write (struct file *fp, struct uio *uio, 98 struct ucred *cred, int flags, struct thread *td); 99 static int pipe_close (struct file *fp, struct thread *td); 100 static int pipe_shutdown (struct file *fp, int how, struct thread *td); 101 static int pipe_poll (struct file *fp, int events, struct ucred *cred, 102 struct thread *td); 103 static int pipe_kqfilter (struct file *fp, struct knote *kn); 104 static int pipe_stat (struct file *fp, struct stat *sb, struct thread *td); 105 static int pipe_ioctl (struct file *fp, u_long cmd, caddr_t data, struct thread *td); 106 107 static struct fileops pipeops = { 108 NULL, /* port */ 109 NULL, /* clone */ 110 pipe_read, pipe_write, pipe_ioctl, pipe_poll, pipe_kqfilter, 111 pipe_stat, pipe_close, pipe_shutdown 112 }; 113 114 static void filt_pipedetach(struct knote *kn); 115 static int filt_piperead(struct knote *kn, long hint); 116 static int filt_pipewrite(struct knote *kn, long hint); 117 118 static struct filterops pipe_rfiltops = 119 { 1, NULL, filt_pipedetach, filt_piperead }; 120 static struct filterops pipe_wfiltops = 121 { 1, NULL, filt_pipedetach, filt_pipewrite }; 122 123 MALLOC_DEFINE(M_PIPE, "pipe", "pipe structures"); 124 125 /* 126 * Default pipe buffer size(s), this can be kind-of large now because pipe 127 * space is pageable. The pipe code will try to maintain locality of 128 * reference for performance reasons, so small amounts of outstanding I/O 129 * will not wipe the cache. 130 */ 131 #define MINPIPESIZE (PIPE_SIZE/3) 132 #define MAXPIPESIZE (2*PIPE_SIZE/3) 133 134 /* 135 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but 136 * is there so that on large systems, we don't exhaust it. 137 */ 138 #define MAXPIPEKVA (8*1024*1024) 139 140 /* 141 * Limit for direct transfers, we cannot, of course limit 142 * the amount of kva for pipes in general though. 143 */ 144 #define LIMITPIPEKVA (16*1024*1024) 145 146 /* 147 * Limit the number of "big" pipes 148 */ 149 #define LIMITBIGPIPES 32 150 #define PIPEQ_MAX_CACHE 16 /* per-cpu pipe structure cache */ 151 152 static int pipe_maxbig = LIMITBIGPIPES; 153 static int pipe_maxcache = PIPEQ_MAX_CACHE; 154 static int pipe_nbig; 155 static int pipe_bcache_alloc; 156 static int pipe_bkmem_alloc; 157 static int pipe_dwrite_enable = 1; /* 0:copy, 1:kmem/sfbuf 2:force */ 158 static int pipe_dwrite_sfbuf = 1; /* 0:kmem_map 1:sfbufs 2:sfbufs_dmap */ 159 /* 3:sfbuf_dmap w/ forced invlpg */ 160 161 SYSCTL_NODE(_kern, OID_AUTO, pipe, CTLFLAG_RW, 0, "Pipe operation"); 162 SYSCTL_INT(_kern_pipe, OID_AUTO, nbig, 163 CTLFLAG_RD, &pipe_nbig, 0, "numer of big pipes allocated"); 164 SYSCTL_INT(_kern_pipe, OID_AUTO, maxcache, 165 CTLFLAG_RW, &pipe_maxcache, 0, "max pipes cached per-cpu"); 166 SYSCTL_INT(_kern_pipe, OID_AUTO, maxbig, 167 CTLFLAG_RW, &pipe_maxbig, 0, "max number of big pipes"); 168 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_enable, 169 CTLFLAG_RW, &pipe_dwrite_enable, 0, "1:enable/2:force direct writes"); 170 SYSCTL_INT(_kern_pipe, OID_AUTO, dwrite_sfbuf, 171 CTLFLAG_RW, &pipe_dwrite_sfbuf, 0, 172 "(if dwrite_enable) 0:kmem 1:sfbuf 2:sfbuf_dmap 3:sfbuf_dmap_forceinvlpg"); 173 #if !defined(NO_PIPE_SYSCTL_STATS) 174 SYSCTL_INT(_kern_pipe, OID_AUTO, bcache_alloc, 175 CTLFLAG_RW, &pipe_bcache_alloc, 0, "pipe buffer from pcpu cache"); 176 SYSCTL_INT(_kern_pipe, OID_AUTO, bkmem_alloc, 177 CTLFLAG_RW, &pipe_bkmem_alloc, 0, "pipe buffer from kmem"); 178 #endif 179 180 static void pipeclose (struct pipe *cpipe); 181 static void pipe_free_kmem (struct pipe *cpipe); 182 static int pipe_create (struct pipe **cpipep); 183 static __inline int pipelock (struct pipe *cpipe, int catch); 184 static __inline void pipeunlock (struct pipe *cpipe); 185 static __inline void pipeselwakeup (struct pipe *cpipe); 186 #ifndef PIPE_NODIRECT 187 static int pipe_build_write_buffer (struct pipe *wpipe, struct uio *uio); 188 static int pipe_direct_write (struct pipe *wpipe, struct uio *uio); 189 static void pipe_clone_write_buffer (struct pipe *wpipe); 190 #endif 191 static int pipespace (struct pipe *cpipe, int size); 192 193 /* 194 * The pipe system call for the DTYPE_PIPE type of pipes 195 * 196 * pipe_ARgs(int dummy) 197 */ 198 199 /* ARGSUSED */ 200 int 201 pipe(struct pipe_args *uap) 202 { 203 struct thread *td = curthread; 204 struct proc *p = td->td_proc; 205 struct filedesc *fdp; 206 struct file *rf, *wf; 207 struct pipe *rpipe, *wpipe; 208 int fd1, fd2, error; 209 210 KKASSERT(p); 211 fdp = p->p_fd; 212 213 rpipe = wpipe = NULL; 214 if (pipe_create(&rpipe) || pipe_create(&wpipe)) { 215 pipeclose(rpipe); 216 pipeclose(wpipe); 217 return (ENFILE); 218 } 219 220 rpipe->pipe_state |= PIPE_DIRECTOK; 221 wpipe->pipe_state |= PIPE_DIRECTOK; 222 223 /* 224 * Select the direct-map features to use for this pipe. Since the 225 * sysctl's can change on the fly we record the settings when the 226 * pipe is created. 227 * 228 * Generally speaking the system will default to what we consider 229 * to be the best-balanced and most stable option. Right now this 230 * is SFBUF1. Modes 2 and 3 are considered experiemental at the 231 * moment. 232 */ 233 wpipe->pipe_feature = PIPE_COPY; 234 if (pipe_dwrite_enable) { 235 switch(pipe_dwrite_sfbuf) { 236 case 0: 237 wpipe->pipe_feature = PIPE_KMEM; 238 break; 239 case 1: 240 wpipe->pipe_feature = PIPE_SFBUF1; 241 break; 242 case 2: 243 case 3: 244 wpipe->pipe_feature = PIPE_SFBUF2; 245 break; 246 } 247 } 248 rpipe->pipe_feature = wpipe->pipe_feature; 249 250 error = falloc(p, &rf, &fd1); 251 if (error) { 252 pipeclose(rpipe); 253 pipeclose(wpipe); 254 return (error); 255 } 256 uap->sysmsg_fds[0] = fd1; 257 258 /* 259 * Warning: once we've gotten past allocation of the fd for the 260 * read-side, we can only drop the read side via fdrop() in order 261 * to avoid races against processes which manage to dup() the read 262 * side while we are blocked trying to allocate the write side. 263 */ 264 rf->f_type = DTYPE_PIPE; 265 rf->f_flag = FREAD | FWRITE; 266 rf->f_ops = &pipeops; 267 rf->f_data = rpipe; 268 error = falloc(p, &wf, &fd2); 269 if (error) { 270 if (fdp->fd_files[fd1].fp == rf) { 271 funsetfd(fdp, fd1); 272 fdrop(rf, td); 273 } 274 fdrop(rf, td); 275 /* rpipe has been closed by fdrop(). */ 276 pipeclose(wpipe); 277 return (error); 278 } 279 wf->f_type = DTYPE_PIPE; 280 wf->f_flag = FREAD | FWRITE; 281 wf->f_ops = &pipeops; 282 wf->f_data = wpipe; 283 uap->sysmsg_fds[1] = fd2; 284 285 rpipe->pipe_peer = wpipe; 286 wpipe->pipe_peer = rpipe; 287 fdrop(rf, td); 288 fdrop(wf, td); 289 290 return (0); 291 } 292 293 /* 294 * Allocate kva for pipe circular buffer, the space is pageable 295 * This routine will 'realloc' the size of a pipe safely, if it fails 296 * it will retain the old buffer. 297 * If it fails it will return ENOMEM. 298 */ 299 static int 300 pipespace(struct pipe *cpipe, int size) 301 { 302 struct vm_object *object; 303 caddr_t buffer; 304 int npages, error; 305 306 npages = round_page(size) / PAGE_SIZE; 307 object = cpipe->pipe_buffer.object; 308 309 /* 310 * [re]create the object if necessary and reserve space for it 311 * in the kernel_map. The object and memory are pageable. On 312 * success, free the old resources before assigning the new 313 * ones. 314 */ 315 if (object == NULL || object->size != npages) { 316 object = vm_object_allocate(OBJT_DEFAULT, npages); 317 buffer = (caddr_t) vm_map_min(kernel_map); 318 319 error = vm_map_find(kernel_map, object, 0, 320 (vm_offset_t *) &buffer, size, 1, 321 VM_PROT_ALL, VM_PROT_ALL, 0); 322 323 if (error != KERN_SUCCESS) { 324 vm_object_deallocate(object); 325 return (ENOMEM); 326 } 327 pipe_free_kmem(cpipe); 328 cpipe->pipe_buffer.object = object; 329 cpipe->pipe_buffer.buffer = buffer; 330 cpipe->pipe_buffer.size = size; 331 ++pipe_bkmem_alloc; 332 } else { 333 ++pipe_bcache_alloc; 334 } 335 cpipe->pipe_buffer.in = 0; 336 cpipe->pipe_buffer.out = 0; 337 cpipe->pipe_buffer.cnt = 0; 338 return (0); 339 } 340 341 /* 342 * Initialize and allocate VM and memory for pipe, pulling the pipe from 343 * our per-cpu cache if possible. For now make sure it is sized for the 344 * smaller PIPE_SIZE default. 345 */ 346 static int 347 pipe_create(cpipep) 348 struct pipe **cpipep; 349 { 350 globaldata_t gd = mycpu; 351 struct pipe *cpipe; 352 int error; 353 354 if ((cpipe = gd->gd_pipeq) != NULL) { 355 gd->gd_pipeq = cpipe->pipe_peer; 356 --gd->gd_pipeqcount; 357 cpipe->pipe_peer = NULL; 358 } else { 359 cpipe = malloc(sizeof(struct pipe), M_PIPE, M_WAITOK|M_ZERO); 360 } 361 *cpipep = cpipe; 362 if ((error = pipespace(cpipe, PIPE_SIZE)) != 0) 363 return (error); 364 vfs_timestamp(&cpipe->pipe_ctime); 365 cpipe->pipe_atime = cpipe->pipe_ctime; 366 cpipe->pipe_mtime = cpipe->pipe_ctime; 367 return (0); 368 } 369 370 371 /* 372 * lock a pipe for I/O, blocking other access 373 */ 374 static __inline int 375 pipelock(cpipe, catch) 376 struct pipe *cpipe; 377 int catch; 378 { 379 int error; 380 381 while (cpipe->pipe_state & PIPE_LOCK) { 382 cpipe->pipe_state |= PIPE_LWANT; 383 error = tsleep(cpipe, (catch ? PCATCH : 0), "pipelk", 0); 384 if (error != 0) 385 return (error); 386 } 387 cpipe->pipe_state |= PIPE_LOCK; 388 return (0); 389 } 390 391 /* 392 * unlock a pipe I/O lock 393 */ 394 static __inline void 395 pipeunlock(cpipe) 396 struct pipe *cpipe; 397 { 398 399 cpipe->pipe_state &= ~PIPE_LOCK; 400 if (cpipe->pipe_state & PIPE_LWANT) { 401 cpipe->pipe_state &= ~PIPE_LWANT; 402 wakeup(cpipe); 403 } 404 } 405 406 static __inline void 407 pipeselwakeup(cpipe) 408 struct pipe *cpipe; 409 { 410 411 if (cpipe->pipe_state & PIPE_SEL) { 412 cpipe->pipe_state &= ~PIPE_SEL; 413 selwakeup(&cpipe->pipe_sel); 414 } 415 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) 416 pgsigio(cpipe->pipe_sigio, SIGIO, 0); 417 KNOTE(&cpipe->pipe_sel.si_note, 0); 418 } 419 420 /* ARGSUSED */ 421 static int 422 pipe_read(struct file *fp, struct uio *uio, struct ucred *cred, 423 int flags, struct thread *td) 424 { 425 struct pipe *rpipe = (struct pipe *) fp->f_data; 426 int error; 427 int nread = 0; 428 u_int size; 429 430 ++rpipe->pipe_busy; 431 error = pipelock(rpipe, 1); 432 if (error) 433 goto unlocked_error; 434 435 while (uio->uio_resid) { 436 caddr_t va; 437 438 if (rpipe->pipe_buffer.cnt > 0) { 439 /* 440 * normal pipe buffer receive 441 */ 442 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 443 if (size > rpipe->pipe_buffer.cnt) 444 size = rpipe->pipe_buffer.cnt; 445 if (size > (u_int) uio->uio_resid) 446 size = (u_int) uio->uio_resid; 447 448 error = uiomove(&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 449 size, uio); 450 if (error) 451 break; 452 453 rpipe->pipe_buffer.out += size; 454 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 455 rpipe->pipe_buffer.out = 0; 456 457 rpipe->pipe_buffer.cnt -= size; 458 459 /* 460 * If there is no more to read in the pipe, reset 461 * its pointers to the beginning. This improves 462 * cache hit stats. 463 */ 464 if (rpipe->pipe_buffer.cnt == 0) { 465 rpipe->pipe_buffer.in = 0; 466 rpipe->pipe_buffer.out = 0; 467 } 468 nread += size; 469 #ifndef PIPE_NODIRECT 470 } else if (rpipe->pipe_kva && 471 rpipe->pipe_feature == PIPE_KMEM && 472 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 473 == PIPE_DIRECTW 474 ) { 475 /* 476 * Direct copy using source-side kva mapping 477 */ 478 size = rpipe->pipe_map.xio_bytes - 479 rpipe->pipe_buffer.out; 480 if (size > (u_int)uio->uio_resid) 481 size = (u_int)uio->uio_resid; 482 va = (caddr_t)rpipe->pipe_kva + 483 xio_kvaoffset(&rpipe->pipe_map, rpipe->pipe_buffer.out); 484 error = uiomove(va, size, uio); 485 if (error) 486 break; 487 nread += size; 488 rpipe->pipe_buffer.out += size; 489 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) { 490 rpipe->pipe_state |= PIPE_DIRECTIP; 491 rpipe->pipe_state &= ~PIPE_DIRECTW; 492 /* reset out index for copy mode */ 493 rpipe->pipe_buffer.out = 0; 494 wakeup(rpipe); 495 } 496 } else if (rpipe->pipe_buffer.out != rpipe->pipe_map.xio_bytes && 497 rpipe->pipe_kva && 498 rpipe->pipe_feature == PIPE_SFBUF2 && 499 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 500 == PIPE_DIRECTW 501 ) { 502 /* 503 * Direct copy, bypassing a kernel buffer. We cannot 504 * mess with the direct-write buffer until 505 * PIPE_DIRECTIP is cleared. In order to prevent 506 * the pipe_write code from racing itself in 507 * direct_write, we set DIRECTIP when we clear 508 * DIRECTW after we have exhausted the buffer. 509 */ 510 if (pipe_dwrite_sfbuf == 3) 511 rpipe->pipe_kvamask = 0; 512 pmap_qenter2(rpipe->pipe_kva, rpipe->pipe_map.xio_pages, 513 rpipe->pipe_map.xio_npages, 514 &rpipe->pipe_kvamask); 515 size = rpipe->pipe_map.xio_bytes - 516 rpipe->pipe_buffer.out; 517 if (size > (u_int)uio->uio_resid) 518 size = (u_int)uio->uio_resid; 519 va = (caddr_t)rpipe->pipe_kva + xio_kvaoffset(&rpipe->pipe_map, rpipe->pipe_buffer.out); 520 error = uiomove(va, size, uio); 521 if (error) 522 break; 523 nread += size; 524 rpipe->pipe_buffer.out += size; 525 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) { 526 rpipe->pipe_state |= PIPE_DIRECTIP; 527 rpipe->pipe_state &= ~PIPE_DIRECTW; 528 /* reset out index for copy mode */ 529 rpipe->pipe_buffer.out = 0; 530 wakeup(rpipe); 531 } 532 } else if (rpipe->pipe_buffer.out != rpipe->pipe_map.xio_bytes && 533 rpipe->pipe_feature == PIPE_SFBUF1 && 534 (rpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) 535 == PIPE_DIRECTW 536 ) { 537 /* 538 * Direct copy, bypassing a kernel buffer. We cannot 539 * mess with the direct-write buffer until 540 * PIPE_DIRECTIP is cleared. In order to prevent 541 * the pipe_write code from racing itself in 542 * direct_write, we set DIRECTIP when we clear 543 * DIRECTW after we have exhausted the buffer. 544 */ 545 error = xio_uio_copy(&rpipe->pipe_map, rpipe->pipe_buffer.out, uio, &size); 546 if (error) 547 break; 548 nread += size; 549 rpipe->pipe_buffer.out += size; 550 if (rpipe->pipe_buffer.out == rpipe->pipe_map.xio_bytes) { 551 rpipe->pipe_state |= PIPE_DIRECTIP; 552 rpipe->pipe_state &= ~PIPE_DIRECTW; 553 /* reset out index for copy mode */ 554 rpipe->pipe_buffer.out = 0; 555 wakeup(rpipe); 556 } 557 #endif 558 } else { 559 /* 560 * detect EOF condition 561 * read returns 0 on EOF, no need to set error 562 */ 563 if (rpipe->pipe_state & PIPE_EOF) 564 break; 565 566 /* 567 * If the "write-side" has been blocked, wake it up now. 568 */ 569 if (rpipe->pipe_state & PIPE_WANTW) { 570 rpipe->pipe_state &= ~PIPE_WANTW; 571 wakeup(rpipe); 572 } 573 574 /* 575 * Break if some data was read. 576 */ 577 if (nread > 0) 578 break; 579 580 /* 581 * Unlock the pipe buffer for our remaining 582 * processing. We will either break out with an 583 * error or we will sleep and relock to loop. 584 */ 585 pipeunlock(rpipe); 586 587 /* 588 * Handle non-blocking mode operation or 589 * wait for more data. 590 */ 591 if (fp->f_flag & FNONBLOCK) { 592 error = EAGAIN; 593 } else { 594 rpipe->pipe_state |= PIPE_WANTR; 595 if ((error = tsleep(rpipe, PCATCH|PNORESCHED, 596 "piperd", 0)) == 0) { 597 error = pipelock(rpipe, 1); 598 } 599 } 600 if (error) 601 goto unlocked_error; 602 } 603 } 604 pipeunlock(rpipe); 605 606 if (error == 0) 607 vfs_timestamp(&rpipe->pipe_atime); 608 unlocked_error: 609 --rpipe->pipe_busy; 610 611 /* 612 * PIPE_WANT processing only makes sense if pipe_busy is 0. 613 */ 614 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 615 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 616 wakeup(rpipe); 617 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 618 /* 619 * Handle write blocking hysteresis. 620 */ 621 if (rpipe->pipe_state & PIPE_WANTW) { 622 rpipe->pipe_state &= ~PIPE_WANTW; 623 wakeup(rpipe); 624 } 625 } 626 627 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 628 pipeselwakeup(rpipe); 629 return (error); 630 } 631 632 #ifndef PIPE_NODIRECT 633 /* 634 * Map the sending processes' buffer into kernel space and wire it. 635 * This is similar to a physical write operation. 636 */ 637 static int 638 pipe_build_write_buffer(wpipe, uio) 639 struct pipe *wpipe; 640 struct uio *uio; 641 { 642 int error; 643 u_int size; 644 645 size = (u_int) uio->uio_iov->iov_len; 646 if (size > wpipe->pipe_buffer.size) 647 size = wpipe->pipe_buffer.size; 648 649 if (uio->uio_segflg == UIO_SYSSPACE) { 650 error = xio_init_kbuf(&wpipe->pipe_map, uio->uio_iov->iov_base, 651 size); 652 } else { 653 error = xio_init_ubuf(&wpipe->pipe_map, uio->uio_iov->iov_base, 654 size, XIOF_READ); 655 } 656 wpipe->pipe_buffer.out = 0; 657 if (error) 658 return(error); 659 660 /* 661 * Create a kernel map for KMEM and SFBUF2 copy modes. SFBUF2 will 662 * map the pages on the target while KMEM maps the pages now. 663 */ 664 switch(wpipe->pipe_feature) { 665 case PIPE_KMEM: 666 case PIPE_SFBUF2: 667 if (wpipe->pipe_kva == NULL) { 668 wpipe->pipe_kva = 669 kmem_alloc_nofault(kernel_map, XIO_INTERNAL_SIZE); 670 wpipe->pipe_kvamask = 0; 671 } 672 if (wpipe->pipe_feature == PIPE_KMEM) { 673 pmap_qenter(wpipe->pipe_kva, wpipe->pipe_map.xio_pages, 674 wpipe->pipe_map.xio_npages); 675 } 676 break; 677 default: 678 break; 679 } 680 681 /* 682 * And update the uio data. The XIO might have loaded fewer bytes 683 * then requested so reload 'size'. 684 */ 685 size = wpipe->pipe_map.xio_bytes; 686 uio->uio_iov->iov_len -= size; 687 uio->uio_iov->iov_base += size; 688 if (uio->uio_iov->iov_len == 0) 689 uio->uio_iov++; 690 uio->uio_resid -= size; 691 uio->uio_offset += size; 692 return (0); 693 } 694 695 /* 696 * In the case of a signal, the writing process might go away. This 697 * code copies the data into the circular buffer so that the source 698 * pages can be freed without loss of data. 699 * 700 * Note that in direct mode pipe_buffer.out is used to track the 701 * XIO offset. We are converting the direct mode into buffered mode 702 * which changes the meaning of pipe_buffer.out. 703 */ 704 static void 705 pipe_clone_write_buffer(wpipe) 706 struct pipe *wpipe; 707 { 708 int size; 709 int offset; 710 711 offset = wpipe->pipe_buffer.out; 712 size = wpipe->pipe_map.xio_bytes - offset; 713 714 KKASSERT(size <= wpipe->pipe_buffer.size); 715 716 wpipe->pipe_buffer.in = size; 717 wpipe->pipe_buffer.out = 0; 718 wpipe->pipe_buffer.cnt = size; 719 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP); 720 721 xio_copy_xtok(&wpipe->pipe_map, offset, wpipe->pipe_buffer.buffer, size); 722 xio_release(&wpipe->pipe_map); 723 if (wpipe->pipe_kva) { 724 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES); 725 kmem_free(kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE); 726 wpipe->pipe_kva = NULL; 727 } 728 } 729 730 /* 731 * This implements the pipe buffer write mechanism. Note that only 732 * a direct write OR a normal pipe write can be pending at any given time. 733 * If there are any characters in the pipe buffer, the direct write will 734 * be deferred until the receiving process grabs all of the bytes from 735 * the pipe buffer. Then the direct mapping write is set-up. 736 */ 737 static int 738 pipe_direct_write(wpipe, uio) 739 struct pipe *wpipe; 740 struct uio *uio; 741 { 742 int error; 743 744 retry: 745 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 746 if (wpipe->pipe_state & PIPE_WANTR) { 747 wpipe->pipe_state &= ~PIPE_WANTR; 748 wakeup(wpipe); 749 } 750 wpipe->pipe_state |= PIPE_WANTW; 751 error = tsleep(wpipe, PCATCH, "pipdww", 0); 752 if (error) 753 goto error2; 754 if (wpipe->pipe_state & PIPE_EOF) { 755 error = EPIPE; 756 goto error2; 757 } 758 } 759 KKASSERT(wpipe->pipe_map.xio_bytes == 0); 760 if (wpipe->pipe_buffer.cnt > 0) { 761 if (wpipe->pipe_state & PIPE_WANTR) { 762 wpipe->pipe_state &= ~PIPE_WANTR; 763 wakeup(wpipe); 764 } 765 766 wpipe->pipe_state |= PIPE_WANTW; 767 error = tsleep(wpipe, PCATCH, "pipdwc", 0); 768 if (error) 769 goto error2; 770 if (wpipe->pipe_state & PIPE_EOF) { 771 error = EPIPE; 772 goto error2; 773 } 774 goto retry; 775 } 776 777 /* 778 * Build our direct-write buffer 779 */ 780 wpipe->pipe_state |= PIPE_DIRECTW | PIPE_DIRECTIP; 781 error = pipe_build_write_buffer(wpipe, uio); 782 if (error) 783 goto error1; 784 wpipe->pipe_state &= ~PIPE_DIRECTIP; 785 786 /* 787 * Wait until the receiver has snarfed the data. Since we are likely 788 * going to sleep we optimize the case and yield synchronously, 789 * possibly avoiding the tsleep(). 790 */ 791 error = 0; 792 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 793 if (wpipe->pipe_state & PIPE_EOF) { 794 pipelock(wpipe, 0); 795 xio_release(&wpipe->pipe_map); 796 if (wpipe->pipe_kva) { 797 pmap_qremove(wpipe->pipe_kva, XIO_INTERNAL_PAGES); 798 kmem_free(kernel_map, wpipe->pipe_kva, XIO_INTERNAL_SIZE); 799 wpipe->pipe_kva = NULL; 800 } 801 pipeunlock(wpipe); 802 pipeselwakeup(wpipe); 803 error = EPIPE; 804 goto error1; 805 } 806 if (wpipe->pipe_state & PIPE_WANTR) { 807 wpipe->pipe_state &= ~PIPE_WANTR; 808 wakeup(wpipe); 809 } 810 pipeselwakeup(wpipe); 811 error = tsleep(wpipe, PCATCH|PNORESCHED, "pipdwt", 0); 812 } 813 pipelock(wpipe,0); 814 if (wpipe->pipe_state & PIPE_DIRECTW) { 815 /* 816 * this bit of trickery substitutes a kernel buffer for 817 * the process that might be going away. 818 */ 819 pipe_clone_write_buffer(wpipe); 820 KKASSERT((wpipe->pipe_state & PIPE_DIRECTIP) == 0); 821 } else { 822 /* 823 * note: The pipe_kva mapping is not qremove'd here. For 824 * legacy PIPE_KMEM mode this constitutes an improvement 825 * over the original FreeBSD-4 algorithm. For PIPE_SFBUF2 826 * mode the kva mapping must not be removed to get the 827 * caching benefit. 828 * 829 * For testing purposes we will give the original algorithm 830 * the benefit of the doubt 'what it could have been', and 831 * keep the optimization. 832 */ 833 KKASSERT(wpipe->pipe_state & PIPE_DIRECTIP); 834 xio_release(&wpipe->pipe_map); 835 wpipe->pipe_state &= ~PIPE_DIRECTIP; 836 } 837 pipeunlock(wpipe); 838 return (error); 839 840 /* 841 * Direct-write error, clear the direct write flags. 842 */ 843 error1: 844 wpipe->pipe_state &= ~(PIPE_DIRECTW | PIPE_DIRECTIP); 845 /* fallthrough */ 846 847 /* 848 * General error, wakeup the other side if it happens to be sleeping. 849 */ 850 error2: 851 wakeup(wpipe); 852 return (error); 853 } 854 #endif 855 856 static int 857 pipe_write(struct file *fp, struct uio *uio, struct ucred *cred, 858 int flags, struct thread *td) 859 { 860 int error = 0; 861 int orig_resid; 862 struct pipe *wpipe, *rpipe; 863 864 rpipe = (struct pipe *) fp->f_data; 865 wpipe = rpipe->pipe_peer; 866 867 /* 868 * detect loss of pipe read side, issue SIGPIPE if lost. 869 */ 870 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 871 return (EPIPE); 872 } 873 ++wpipe->pipe_busy; 874 875 /* 876 * If it is advantageous to resize the pipe buffer, do 877 * so. 878 */ 879 if ((uio->uio_resid > PIPE_SIZE) && 880 (pipe_nbig < pipe_maxbig) && 881 (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) == 0 && 882 (wpipe->pipe_buffer.size <= PIPE_SIZE) && 883 (wpipe->pipe_buffer.cnt == 0)) { 884 885 if ((error = pipelock(wpipe,1)) == 0) { 886 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 887 pipe_nbig++; 888 pipeunlock(wpipe); 889 } 890 } 891 892 /* 893 * If an early error occured unbusy and return, waking up any pending 894 * readers. 895 */ 896 if (error) { 897 --wpipe->pipe_busy; 898 if ((wpipe->pipe_busy == 0) && 899 (wpipe->pipe_state & PIPE_WANT)) { 900 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 901 wakeup(wpipe); 902 } 903 return(error); 904 } 905 906 KASSERT(wpipe->pipe_buffer.buffer != NULL, ("pipe buffer gone")); 907 908 orig_resid = uio->uio_resid; 909 910 while (uio->uio_resid) { 911 int space; 912 913 #ifndef PIPE_NODIRECT 914 /* 915 * If the transfer is large, we can gain performance if 916 * we do process-to-process copies directly. 917 * If the write is non-blocking, we don't use the 918 * direct write mechanism. 919 * 920 * The direct write mechanism will detect the reader going 921 * away on us. 922 */ 923 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT || 924 pipe_dwrite_enable > 1) && 925 (fp->f_flag & FNONBLOCK) == 0 && 926 pipe_dwrite_enable) { 927 error = pipe_direct_write( wpipe, uio); 928 if (error) 929 break; 930 continue; 931 } 932 #endif 933 934 /* 935 * Pipe buffered writes cannot be coincidental with 936 * direct writes. We wait until the currently executing 937 * direct write is completed before we start filling the 938 * pipe buffer. We break out if a signal occurs or the 939 * reader goes away. 940 */ 941 retrywrite: 942 while (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 943 if (wpipe->pipe_state & PIPE_WANTR) { 944 wpipe->pipe_state &= ~PIPE_WANTR; 945 wakeup(wpipe); 946 } 947 error = tsleep(wpipe, PCATCH, "pipbww", 0); 948 if (wpipe->pipe_state & PIPE_EOF) 949 break; 950 if (error) 951 break; 952 } 953 if (wpipe->pipe_state & PIPE_EOF) { 954 error = EPIPE; 955 break; 956 } 957 958 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 959 960 /* Writes of size <= PIPE_BUF must be atomic. */ 961 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 962 space = 0; 963 964 /* 965 * Write to fill, read size handles write hysteresis. Also 966 * additional restrictions can cause select-based non-blocking 967 * writes to spin. 968 */ 969 if (space > 0) { 970 if ((error = pipelock(wpipe,1)) == 0) { 971 int size; /* Transfer size */ 972 int segsize; /* first segment to transfer */ 973 974 /* 975 * It is possible for a direct write to 976 * slip in on us... handle it here... 977 */ 978 if (wpipe->pipe_state & (PIPE_DIRECTW|PIPE_DIRECTIP)) { 979 pipeunlock(wpipe); 980 goto retrywrite; 981 } 982 /* 983 * If a process blocked in uiomove, our 984 * value for space might be bad. 985 * 986 * XXX will we be ok if the reader has gone 987 * away here? 988 */ 989 if (space > wpipe->pipe_buffer.size - 990 wpipe->pipe_buffer.cnt) { 991 pipeunlock(wpipe); 992 goto retrywrite; 993 } 994 995 /* 996 * Transfer size is minimum of uio transfer 997 * and free space in pipe buffer. 998 */ 999 if (space > uio->uio_resid) 1000 size = uio->uio_resid; 1001 else 1002 size = space; 1003 /* 1004 * First segment to transfer is minimum of 1005 * transfer size and contiguous space in 1006 * pipe buffer. If first segment to transfer 1007 * is less than the transfer size, we've got 1008 * a wraparound in the buffer. 1009 */ 1010 segsize = wpipe->pipe_buffer.size - 1011 wpipe->pipe_buffer.in; 1012 if (segsize > size) 1013 segsize = size; 1014 1015 /* Transfer first segment */ 1016 1017 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1018 segsize, uio); 1019 1020 if (error == 0 && segsize < size) { 1021 /* 1022 * Transfer remaining part now, to 1023 * support atomic writes. Wraparound 1024 * happened. 1025 */ 1026 if (wpipe->pipe_buffer.in + segsize != 1027 wpipe->pipe_buffer.size) 1028 panic("Expected pipe buffer wraparound disappeared"); 1029 1030 error = uiomove(&wpipe->pipe_buffer.buffer[0], 1031 size - segsize, uio); 1032 } 1033 if (error == 0) { 1034 wpipe->pipe_buffer.in += size; 1035 if (wpipe->pipe_buffer.in >= 1036 wpipe->pipe_buffer.size) { 1037 if (wpipe->pipe_buffer.in != size - segsize + wpipe->pipe_buffer.size) 1038 panic("Expected wraparound bad"); 1039 wpipe->pipe_buffer.in = size - segsize; 1040 } 1041 1042 wpipe->pipe_buffer.cnt += size; 1043 if (wpipe->pipe_buffer.cnt > wpipe->pipe_buffer.size) 1044 panic("Pipe buffer overflow"); 1045 1046 } 1047 pipeunlock(wpipe); 1048 } 1049 if (error) 1050 break; 1051 1052 } else { 1053 /* 1054 * If the "read-side" has been blocked, wake it up now 1055 * and yield to let it drain synchronously rather 1056 * then block. 1057 */ 1058 if (wpipe->pipe_state & PIPE_WANTR) { 1059 wpipe->pipe_state &= ~PIPE_WANTR; 1060 wakeup(wpipe); 1061 } 1062 1063 /* 1064 * don't block on non-blocking I/O 1065 */ 1066 if (fp->f_flag & FNONBLOCK) { 1067 error = EAGAIN; 1068 break; 1069 } 1070 1071 /* 1072 * We have no more space and have something to offer, 1073 * wake up select/poll. 1074 */ 1075 pipeselwakeup(wpipe); 1076 1077 wpipe->pipe_state |= PIPE_WANTW; 1078 error = tsleep(wpipe, PCATCH|PNORESCHED, "pipewr", 0); 1079 if (error != 0) 1080 break; 1081 /* 1082 * If read side wants to go away, we just issue a signal 1083 * to ourselves. 1084 */ 1085 if (wpipe->pipe_state & PIPE_EOF) { 1086 error = EPIPE; 1087 break; 1088 } 1089 } 1090 } 1091 1092 --wpipe->pipe_busy; 1093 1094 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1095 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1096 wakeup(wpipe); 1097 } else if (wpipe->pipe_buffer.cnt > 0) { 1098 /* 1099 * If we have put any characters in the buffer, we wake up 1100 * the reader. 1101 */ 1102 if (wpipe->pipe_state & PIPE_WANTR) { 1103 wpipe->pipe_state &= ~PIPE_WANTR; 1104 wakeup(wpipe); 1105 } 1106 } 1107 1108 /* 1109 * Don't return EPIPE if I/O was successful 1110 */ 1111 if ((wpipe->pipe_buffer.cnt == 0) && 1112 (uio->uio_resid == 0) && 1113 (error == EPIPE)) { 1114 error = 0; 1115 } 1116 1117 if (error == 0) 1118 vfs_timestamp(&wpipe->pipe_mtime); 1119 1120 /* 1121 * We have something to offer, 1122 * wake up select/poll. 1123 */ 1124 if (wpipe->pipe_buffer.cnt) 1125 pipeselwakeup(wpipe); 1126 1127 return (error); 1128 } 1129 1130 /* 1131 * we implement a very minimal set of ioctls for compatibility with sockets. 1132 */ 1133 int 1134 pipe_ioctl(struct file *fp, u_long cmd, caddr_t data, struct thread *td) 1135 { 1136 struct pipe *mpipe = (struct pipe *)fp->f_data; 1137 1138 switch (cmd) { 1139 1140 case FIONBIO: 1141 return (0); 1142 1143 case FIOASYNC: 1144 if (*(int *)data) { 1145 mpipe->pipe_state |= PIPE_ASYNC; 1146 } else { 1147 mpipe->pipe_state &= ~PIPE_ASYNC; 1148 } 1149 return (0); 1150 1151 case FIONREAD: 1152 if (mpipe->pipe_state & PIPE_DIRECTW) { 1153 *(int *)data = mpipe->pipe_map.xio_bytes - 1154 mpipe->pipe_buffer.out; 1155 } else { 1156 *(int *)data = mpipe->pipe_buffer.cnt; 1157 } 1158 return (0); 1159 1160 case FIOSETOWN: 1161 return (fsetown(*(int *)data, &mpipe->pipe_sigio)); 1162 1163 case FIOGETOWN: 1164 *(int *)data = fgetown(mpipe->pipe_sigio); 1165 return (0); 1166 1167 /* This is deprecated, FIOSETOWN should be used instead. */ 1168 case TIOCSPGRP: 1169 return (fsetown(-(*(int *)data), &mpipe->pipe_sigio)); 1170 1171 /* This is deprecated, FIOGETOWN should be used instead. */ 1172 case TIOCGPGRP: 1173 *(int *)data = -fgetown(mpipe->pipe_sigio); 1174 return (0); 1175 1176 } 1177 return (ENOTTY); 1178 } 1179 1180 int 1181 pipe_poll(struct file *fp, int events, struct ucred *cred, struct thread *td) 1182 { 1183 struct pipe *rpipe = (struct pipe *)fp->f_data; 1184 struct pipe *wpipe; 1185 int revents = 0; 1186 1187 wpipe = rpipe->pipe_peer; 1188 if (events & (POLLIN | POLLRDNORM)) 1189 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1190 (rpipe->pipe_buffer.cnt > 0) || 1191 (rpipe->pipe_state & PIPE_EOF)) 1192 revents |= events & (POLLIN | POLLRDNORM); 1193 1194 if (events & (POLLOUT | POLLWRNORM)) 1195 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) || 1196 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1197 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1198 revents |= events & (POLLOUT | POLLWRNORM); 1199 1200 if ((rpipe->pipe_state & PIPE_EOF) || 1201 (wpipe == NULL) || 1202 (wpipe->pipe_state & PIPE_EOF)) 1203 revents |= POLLHUP; 1204 1205 if (revents == 0) { 1206 if (events & (POLLIN | POLLRDNORM)) { 1207 selrecord(td, &rpipe->pipe_sel); 1208 rpipe->pipe_state |= PIPE_SEL; 1209 } 1210 1211 if (events & (POLLOUT | POLLWRNORM)) { 1212 selrecord(td, &wpipe->pipe_sel); 1213 wpipe->pipe_state |= PIPE_SEL; 1214 } 1215 } 1216 1217 return (revents); 1218 } 1219 1220 static int 1221 pipe_stat(struct file *fp, struct stat *ub, struct thread *td) 1222 { 1223 struct pipe *pipe = (struct pipe *)fp->f_data; 1224 1225 bzero((caddr_t)ub, sizeof(*ub)); 1226 ub->st_mode = S_IFIFO; 1227 ub->st_blksize = pipe->pipe_buffer.size; 1228 ub->st_size = pipe->pipe_buffer.cnt; 1229 if (ub->st_size == 0 && (pipe->pipe_state & PIPE_DIRECTW)) { 1230 ub->st_size = pipe->pipe_map.xio_bytes - 1231 pipe->pipe_buffer.out; 1232 } 1233 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1234 ub->st_atimespec = pipe->pipe_atime; 1235 ub->st_mtimespec = pipe->pipe_mtime; 1236 ub->st_ctimespec = pipe->pipe_ctime; 1237 /* 1238 * Left as 0: st_dev, st_ino, st_nlink, st_uid, st_gid, st_rdev, 1239 * st_flags, st_gen. 1240 * XXX (st_dev, st_ino) should be unique. 1241 */ 1242 return (0); 1243 } 1244 1245 /* ARGSUSED */ 1246 static int 1247 pipe_close(struct file *fp, struct thread *td) 1248 { 1249 struct pipe *cpipe = (struct pipe *)fp->f_data; 1250 1251 fp->f_ops = &badfileops; 1252 fp->f_data = NULL; 1253 funsetown(cpipe->pipe_sigio); 1254 pipeclose(cpipe); 1255 return (0); 1256 } 1257 1258 /* 1259 * Shutdown one or both directions of a full-duplex pipe. 1260 */ 1261 /* ARGSUSED */ 1262 static int 1263 pipe_shutdown(struct file *fp, int how, struct thread *td) 1264 { 1265 struct pipe *rpipe = (struct pipe *)fp->f_data; 1266 struct pipe *wpipe; 1267 int error = EPIPE; 1268 1269 switch(how) { 1270 case SHUT_RDWR: 1271 case SHUT_RD: 1272 if (rpipe) { 1273 rpipe->pipe_state |= PIPE_EOF; 1274 pipeselwakeup(rpipe); 1275 if (rpipe->pipe_busy) 1276 wakeup(rpipe); 1277 error = 0; 1278 } 1279 if (how == SHUT_RD) 1280 break; 1281 /* fall through */ 1282 case SHUT_WR: 1283 if (rpipe && (wpipe = rpipe->pipe_peer) != NULL) { 1284 wpipe->pipe_state |= PIPE_EOF; 1285 pipeselwakeup(wpipe); 1286 if (wpipe->pipe_busy) 1287 wakeup(wpipe); 1288 error = 0; 1289 } 1290 } 1291 return (error); 1292 } 1293 1294 static void 1295 pipe_free_kmem(struct pipe *cpipe) 1296 { 1297 if (cpipe->pipe_buffer.buffer != NULL) { 1298 if (cpipe->pipe_buffer.size > PIPE_SIZE) 1299 --pipe_nbig; 1300 kmem_free(kernel_map, 1301 (vm_offset_t)cpipe->pipe_buffer.buffer, 1302 cpipe->pipe_buffer.size); 1303 cpipe->pipe_buffer.buffer = NULL; 1304 cpipe->pipe_buffer.object = NULL; 1305 } 1306 #ifndef PIPE_NODIRECT 1307 KKASSERT(cpipe->pipe_map.xio_bytes == 0 && 1308 cpipe->pipe_map.xio_offset == 0 && 1309 cpipe->pipe_map.xio_npages == 0); 1310 #endif 1311 } 1312 1313 /* 1314 * shutdown the pipe 1315 */ 1316 static void 1317 pipeclose(struct pipe *cpipe) 1318 { 1319 globaldata_t gd; 1320 struct pipe *ppipe; 1321 1322 if (cpipe == NULL) 1323 return; 1324 1325 pipeselwakeup(cpipe); 1326 1327 /* 1328 * If the other side is blocked, wake it up saying that 1329 * we want to close it down. 1330 */ 1331 while (cpipe->pipe_busy) { 1332 wakeup(cpipe); 1333 cpipe->pipe_state |= PIPE_WANT | PIPE_EOF; 1334 tsleep(cpipe, 0, "pipecl", 0); 1335 } 1336 1337 /* 1338 * Disconnect from peer 1339 */ 1340 if ((ppipe = cpipe->pipe_peer) != NULL) { 1341 pipeselwakeup(ppipe); 1342 1343 ppipe->pipe_state |= PIPE_EOF; 1344 wakeup(ppipe); 1345 KNOTE(&ppipe->pipe_sel.si_note, 0); 1346 ppipe->pipe_peer = NULL; 1347 } 1348 1349 if (cpipe->pipe_kva) { 1350 pmap_qremove(cpipe->pipe_kva, XIO_INTERNAL_PAGES); 1351 kmem_free(kernel_map, cpipe->pipe_kva, XIO_INTERNAL_SIZE); 1352 cpipe->pipe_kva = NULL; 1353 } 1354 1355 /* 1356 * free or cache resources 1357 */ 1358 gd = mycpu; 1359 if (gd->gd_pipeqcount >= pipe_maxcache || 1360 cpipe->pipe_buffer.size != PIPE_SIZE 1361 ) { 1362 pipe_free_kmem(cpipe); 1363 free(cpipe, M_PIPE); 1364 } else { 1365 KKASSERT(cpipe->pipe_map.xio_npages == 0 && 1366 cpipe->pipe_map.xio_bytes == 0 && 1367 cpipe->pipe_map.xio_offset == 0); 1368 cpipe->pipe_state = 0; 1369 cpipe->pipe_busy = 0; 1370 cpipe->pipe_peer = gd->gd_pipeq; 1371 gd->gd_pipeq = cpipe; 1372 ++gd->gd_pipeqcount; 1373 } 1374 } 1375 1376 /*ARGSUSED*/ 1377 static int 1378 pipe_kqfilter(struct file *fp, struct knote *kn) 1379 { 1380 struct pipe *cpipe = (struct pipe *)kn->kn_fp->f_data; 1381 1382 switch (kn->kn_filter) { 1383 case EVFILT_READ: 1384 kn->kn_fop = &pipe_rfiltops; 1385 break; 1386 case EVFILT_WRITE: 1387 kn->kn_fop = &pipe_wfiltops; 1388 cpipe = cpipe->pipe_peer; 1389 if (cpipe == NULL) 1390 /* other end of pipe has been closed */ 1391 return (EPIPE); 1392 break; 1393 default: 1394 return (1); 1395 } 1396 kn->kn_hook = (caddr_t)cpipe; 1397 1398 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext); 1399 return (0); 1400 } 1401 1402 static void 1403 filt_pipedetach(struct knote *kn) 1404 { 1405 struct pipe *cpipe = (struct pipe *)kn->kn_hook; 1406 1407 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext); 1408 } 1409 1410 /*ARGSUSED*/ 1411 static int 1412 filt_piperead(struct knote *kn, long hint) 1413 { 1414 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1415 struct pipe *wpipe = rpipe->pipe_peer; 1416 1417 kn->kn_data = rpipe->pipe_buffer.cnt; 1418 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) { 1419 kn->kn_data = rpipe->pipe_map.xio_bytes - 1420 rpipe->pipe_buffer.out; 1421 } 1422 1423 if ((rpipe->pipe_state & PIPE_EOF) || 1424 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1425 kn->kn_flags |= EV_EOF; 1426 return (1); 1427 } 1428 return (kn->kn_data > 0); 1429 } 1430 1431 /*ARGSUSED*/ 1432 static int 1433 filt_pipewrite(struct knote *kn, long hint) 1434 { 1435 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1436 struct pipe *wpipe = rpipe->pipe_peer; 1437 1438 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1439 kn->kn_data = 0; 1440 kn->kn_flags |= EV_EOF; 1441 return (1); 1442 } 1443 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1444 if (wpipe->pipe_state & PIPE_DIRECTW) 1445 kn->kn_data = 0; 1446 1447 return (kn->kn_data >= PIPE_BUF); 1448 } 1449