1 /* $NetBSD: sys_pipe.c,v 1.20 2001/12/11 18:15:09 jdolecek Exp $ */ 2 3 /* 4 * Copyright (c) 1996 John S. Dyson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice immediately at the beginning of the file, without modification, 12 * this list of conditions, and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Absolutely no warranty of function or purpose is made by the author 17 * John S. Dyson. 18 * 4. Modifications may be freely made to this file if the above conditions 19 * are met. 20 * 21 * $FreeBSD: src/sys/kern/sys_pipe.c,v 1.82 2001/06/15 20:45:01 jlemon Exp $ 22 */ 23 24 /* 25 * This file contains a high-performance replacement for the socket-based 26 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support 27 * all features of sockets, but does do everything that pipes normally 28 * do. 29 * 30 * Adaption for NetBSD UVM, including uvm_loan() based direct write, was 31 * written by Jaromir Dolecek. 32 */ 33 34 /* 35 * This code has two modes of operation, a small write mode and a large 36 * write mode. The small write mode acts like conventional pipes with 37 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the 38 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT 39 * and PIPE_SIZE in size, it is fully mapped into the kernel (on FreeBSD, 40 * those pages are also wired), and the receiving process can copy it directly 41 * from the pages in the sending process. 42 * 43 * If the sending process receives a signal, it is possible that it will 44 * go away, and certainly its address space can change, because control 45 * is returned back to the user-mode side. In that case, the pipe code 46 * arranges to copy the buffer supplied by the user process on FreeBSD, to 47 * a pageable kernel buffer, and the receiving process will grab the data 48 * from the pageable kernel buffer. Since signals don't happen all that often, 49 * the copy operation is normally eliminated. 50 * For NetBSD, the pages are mapped read-only, COW for kernel by uvm_loan(), 51 * so no explicit handling need to be done, all is handled by standard VM 52 * facilities. 53 * 54 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will 55 * happen for small transfers so that the system will not spend all of 56 * its time context switching. PIPE_SIZE is constrained by the 57 * amount of kernel virtual memory. 58 */ 59 60 #include <sys/cdefs.h> 61 __KERNEL_RCSID(0, "$NetBSD: sys_pipe.c,v 1.20 2001/12/11 18:15:09 jdolecek Exp $"); 62 63 #include <sys/param.h> 64 #include <sys/systm.h> 65 #include <sys/proc.h> 66 #include <sys/fcntl.h> 67 #include <sys/file.h> 68 #include <sys/filedesc.h> 69 #include <sys/filio.h> 70 #include <sys/ttycom.h> 71 #include <sys/stat.h> 72 #include <sys/poll.h> 73 #include <sys/signalvar.h> 74 #include <sys/vnode.h> 75 #include <sys/uio.h> 76 #include <sys/lock.h> 77 #ifdef __FreeBSD__ 78 #include <sys/mutex.h> 79 #include <sys/selinfo.h> 80 #include <sys/sysproto.h> 81 #elif defined(__NetBSD__) 82 #include <sys/select.h> 83 #include <sys/malloc.h> 84 #include <sys/mount.h> 85 #include <sys/syscallargs.h> 86 #include <uvm/uvm.h> 87 #include <sys/sysctl.h> 88 #include <sys/kernel.h> 89 #endif /* NetBSD, FreeBSD */ 90 91 #include <sys/pipe.h> 92 93 #ifdef __NetBSD__ 94 /* 95 * Avoid microtime(9), it's slow. We don't guard the read from time(9) 96 * with splclock(9) since we don't actually need to be THAT sure the access 97 * is atomic. 98 */ 99 #define vfs_timestamp(tv) (*(tv) = time) 100 #endif 101 102 /* 103 * Use this define if you want to disable *fancy* VM things. Expect an 104 * approx 30% decrease in transfer rate. This could be useful for 105 * OpenBSD. 106 */ 107 /* #define PIPE_NODIRECT */ 108 109 /* 110 * interfaces to the outside world 111 */ 112 #ifdef __FreeBSD__ 113 static int pipe_read __P((struct file *fp, struct uio *uio, 114 struct ucred *cred, int flags, struct proc *p)); 115 static int pipe_write __P((struct file *fp, struct uio *uio, 116 struct ucred *cred, int flags, struct proc *p)); 117 static int pipe_close __P((struct file *fp, struct proc *p)); 118 static int pipe_poll __P((struct file *fp, int events, struct ucred *cred, 119 struct proc *p)); 120 static int pipe_kqfilter __P((struct file *fp, struct knote *kn)); 121 static int pipe_stat __P((struct file *fp, struct stat *sb, struct proc *p)); 122 static int pipe_ioctl __P((struct file *fp, u_long cmd, caddr_t data, struct proc *p)); 123 124 static struct fileops pipeops = { 125 pipe_read, pipe_write, pipe_ioctl, pipe_poll, pipe_kqfilter, 126 pipe_stat, pipe_close 127 }; 128 129 static void filt_pipedetach(struct knote *kn); 130 static int filt_piperead(struct knote *kn, long hint); 131 static int filt_pipewrite(struct knote *kn, long hint); 132 133 static struct filterops pipe_rfiltops = 134 { 1, NULL, filt_pipedetach, filt_piperead }; 135 static struct filterops pipe_wfiltops = 136 { 1, NULL, filt_pipedetach, filt_pipewrite }; 137 #endif /* FreeBSD */ 138 139 #ifdef __NetBSD__ 140 static int pipe_read __P((struct file *fp, off_t *offset, struct uio *uio, 141 struct ucred *cred, int flags)); 142 static int pipe_write __P((struct file *fp, off_t *offset, struct uio *uio, 143 struct ucred *cred, int flags)); 144 static int pipe_close __P((struct file *fp, struct proc *p)); 145 static int pipe_poll __P((struct file *fp, int events, struct proc *p)); 146 static int pipe_fcntl __P((struct file *fp, u_int com, caddr_t data, 147 struct proc *p)); 148 static int pipe_stat __P((struct file *fp, struct stat *sb, struct proc *p)); 149 static int pipe_ioctl __P((struct file *fp, u_long cmd, caddr_t data, struct proc *p)); 150 151 static struct fileops pipeops = 152 { pipe_read, pipe_write, pipe_ioctl, pipe_fcntl, pipe_poll, 153 pipe_stat, pipe_close }; 154 #endif /* NetBSD */ 155 156 /* 157 * Default pipe buffer size(s), this can be kind-of large now because pipe 158 * space is pageable. The pipe code will try to maintain locality of 159 * reference for performance reasons, so small amounts of outstanding I/O 160 * will not wipe the cache. 161 */ 162 #define MINPIPESIZE (PIPE_SIZE/3) 163 #define MAXPIPESIZE (2*PIPE_SIZE/3) 164 165 /* 166 * Maximum amount of kva for pipes -- this is kind-of a soft limit, but 167 * is there so that on large systems, we don't exhaust it. 168 */ 169 #define MAXPIPEKVA (8*1024*1024) 170 static int maxpipekva = MAXPIPEKVA; 171 172 /* 173 * Limit for direct transfers, we cannot, of course limit 174 * the amount of kva for pipes in general though. 175 */ 176 #define LIMITPIPEKVA (16*1024*1024) 177 static int limitpipekva = LIMITPIPEKVA; 178 179 /* 180 * Limit the number of "big" pipes 181 */ 182 #define LIMITBIGPIPES 32 183 static int maxbigpipes = LIMITBIGPIPES; 184 static int nbigpipe = 0; 185 186 /* 187 * Amount of KVA consumed by pipe buffers. 188 */ 189 static int amountpipekva = 0; 190 191 static void pipeclose __P((struct pipe *)); 192 static void pipe_free_kmem __P((struct pipe *)); 193 static int pipe_create __P((struct pipe **, int)); 194 static __inline int pipelock __P((struct pipe *, int)); 195 static __inline void pipeunlock __P((struct pipe *)); 196 static __inline void pipeselwakeup __P((struct pipe *, struct pipe *)); 197 static int pipespace __P((struct pipe *, int)); 198 199 #ifdef __FreeBSD__ 200 #ifndef PIPE_NODIRECT 201 static int pipe_build_write_buffer __P((struct pipe *wpipe, struct uio *uio)); 202 static void pipe_destroy_write_buffer __P((struct pipe *wpipe)); 203 static int pipe_direct_write __P((struct pipe *wpipe, struct uio *uio)); 204 static void pipe_clone_write_buffer __P((struct pipe *wpipe)); 205 #endif 206 207 static vm_zone_t pipe_zone; 208 #endif /* FreeBSD */ 209 210 #ifdef __NetBSD__ 211 #ifndef PIPE_NODIRECT 212 static int pipe_direct_write __P((struct pipe *, struct uio *)); 213 static int pipe_loan_alloc __P((struct pipe *, int)); 214 static void pipe_loan_free __P((struct pipe *)); 215 #endif /* PIPE_NODIRECT */ 216 217 static struct pool pipe_pool; 218 #endif /* NetBSD */ 219 220 /* 221 * The pipe system call for the DTYPE_PIPE type of pipes 222 */ 223 224 /* ARGSUSED */ 225 #ifdef __FreeBSD__ 226 int 227 pipe(p, uap) 228 struct proc *p; 229 struct pipe_args /* { 230 int dummy; 231 } */ *uap; 232 #elif defined(__NetBSD__) 233 int 234 sys_pipe(p, v, retval) 235 struct proc *p; 236 void *v; 237 register_t *retval; 238 #endif 239 { 240 struct file *rf, *wf; 241 struct pipe *rpipe, *wpipe; 242 int fd, error; 243 244 #ifdef __FreeBSD__ 245 if (pipe_zone == NULL) 246 pipe_zone = zinit("PIPE", sizeof(struct pipe), 0, 0, 4); 247 248 rpipe = wpipe = NULL; 249 if (pipe_create(&rpipe, 1) || pipe_create(&wpipe, 1)) { 250 pipeclose(rpipe); 251 pipeclose(wpipe); 252 return (ENFILE); 253 } 254 255 error = falloc(p, &rf, &fd); 256 if (error) { 257 pipeclose(rpipe); 258 pipeclose(wpipe); 259 return (error); 260 } 261 fhold(rf); 262 p->p_retval[0] = fd; 263 264 /* 265 * Warning: once we've gotten past allocation of the fd for the 266 * read-side, we can only drop the read side via fdrop() in order 267 * to avoid races against processes which manage to dup() the read 268 * side while we are blocked trying to allocate the write side. 269 */ 270 rf->f_flag = FREAD | FWRITE; 271 rf->f_type = DTYPE_PIPE; 272 rf->f_data = (caddr_t)rpipe; 273 rf->f_ops = &pipeops; 274 error = falloc(p, &wf, &fd); 275 if (error) { 276 struct filedesc *fdp = p->p_fd; 277 278 if (fdp->fd_ofiles[p->p_retval[0]] == rf) { 279 fdp->fd_ofiles[p->p_retval[0]] = NULL; 280 fdrop(rf, p); 281 } 282 fdrop(rf, p); 283 /* rpipe has been closed by fdrop(). */ 284 pipeclose(wpipe); 285 return (error); 286 } 287 wf->f_flag = FREAD | FWRITE; 288 wf->f_type = DTYPE_PIPE; 289 wf->f_data = (caddr_t)wpipe; 290 wf->f_ops = &pipeops; 291 p->p_retval[1] = fd; 292 293 rpipe->pipe_peer = wpipe; 294 wpipe->pipe_peer = rpipe; 295 fdrop(rf, p); 296 #endif /* FreeBSD */ 297 298 #ifdef __NetBSD__ 299 rpipe = wpipe = NULL; 300 if (pipe_create(&rpipe, 1) || pipe_create(&wpipe, 0)) { 301 pipeclose(rpipe); 302 pipeclose(wpipe); 303 return (ENFILE); 304 } 305 306 /* 307 * Note: the file structure returned from falloc() is marked 308 * as 'larval' initially. Unless we mark it as 'mature' by 309 * FILE_SET_MATURE(), any attempt to do anything with it would 310 * return EBADF, including e.g. dup(2) or close(2). This avoids 311 * file descriptor races if we block in the second falloc(). 312 */ 313 314 error = falloc(p, &rf, &fd); 315 if (error) 316 goto free2; 317 retval[0] = fd; 318 rf->f_flag = FREAD; 319 rf->f_type = DTYPE_PIPE; 320 rf->f_data = (caddr_t)rpipe; 321 rf->f_ops = &pipeops; 322 323 error = falloc(p, &wf, &fd); 324 if (error) 325 goto free3; 326 retval[1] = fd; 327 wf->f_flag = FWRITE; 328 wf->f_type = DTYPE_PIPE; 329 wf->f_data = (caddr_t)wpipe; 330 wf->f_ops = &pipeops; 331 332 rpipe->pipe_peer = wpipe; 333 wpipe->pipe_peer = rpipe; 334 335 FILE_SET_MATURE(rf); 336 FILE_SET_MATURE(wf); 337 FILE_UNUSE(rf, p); 338 FILE_UNUSE(wf, p); 339 return (0); 340 free3: 341 FILE_UNUSE(rf, p); 342 ffree(rf); 343 fdremove(p->p_fd, retval[0]); 344 free2: 345 pipeclose(wpipe); 346 pipeclose(rpipe); 347 #endif /* NetBSD */ 348 349 return (error); 350 } 351 352 /* 353 * Allocate kva for pipe circular buffer, the space is pageable 354 * This routine will 'realloc' the size of a pipe safely, if it fails 355 * it will retain the old buffer. 356 * If it fails it will return ENOMEM. 357 */ 358 static int 359 pipespace(cpipe, size) 360 struct pipe *cpipe; 361 int size; 362 { 363 caddr_t buffer; 364 #ifdef __FreeBSD__ 365 struct vm_object *object; 366 int npages, error; 367 368 npages = round_page(size)/PAGE_SIZE; 369 /* 370 * Create an object, I don't like the idea of paging to/from 371 * kernel_object. 372 */ 373 mtx_lock(&vm_mtx); 374 object = vm_object_allocate(OBJT_DEFAULT, npages); 375 buffer = (caddr_t) vm_map_min(kernel_map); 376 377 /* 378 * Insert the object into the kernel map, and allocate kva for it. 379 * The map entry is, by default, pageable. 380 */ 381 error = vm_map_find(kernel_map, object, 0, 382 (vm_offset_t *) &buffer, size, 1, 383 VM_PROT_ALL, VM_PROT_ALL, 0); 384 385 if (error != KERN_SUCCESS) { 386 vm_object_deallocate(object); 387 mtx_unlock(&vm_mtx); 388 return (ENOMEM); 389 } 390 #endif /* FreeBSD */ 391 392 #ifdef __NetBSD__ 393 /* 394 * Allocate pageable virtual address space. Physical memory is allocated 395 * on demand. 396 */ 397 buffer = (caddr_t) uvm_km_valloc(kernel_map, round_page(size)); 398 if (buffer == NULL) 399 return (ENOMEM); 400 #endif /* NetBSD */ 401 402 /* free old resources if we're resizing */ 403 pipe_free_kmem(cpipe); 404 #ifdef __FreeBSD__ 405 mtx_unlock(&vm_mtx); 406 cpipe->pipe_buffer.object = object; 407 #endif 408 cpipe->pipe_buffer.buffer = buffer; 409 cpipe->pipe_buffer.size = size; 410 cpipe->pipe_buffer.in = 0; 411 cpipe->pipe_buffer.out = 0; 412 cpipe->pipe_buffer.cnt = 0; 413 amountpipekva += cpipe->pipe_buffer.size; 414 return (0); 415 } 416 417 /* 418 * initialize and allocate VM and memory for pipe 419 */ 420 static int 421 pipe_create(cpipep, allockva) 422 struct pipe **cpipep; 423 int allockva; 424 { 425 struct pipe *cpipe; 426 int error; 427 428 #ifdef __FreeBSD__ 429 *cpipep = zalloc(pipe_zone); 430 #endif 431 #ifdef __NetBSD__ 432 *cpipep = pool_get(&pipe_pool, M_WAITOK); 433 #endif 434 if (*cpipep == NULL) 435 return (ENOMEM); 436 437 cpipe = *cpipep; 438 439 /* Initialize */ 440 memset(cpipe, 0, sizeof(*cpipe)); 441 cpipe->pipe_state = PIPE_SIGNALR; 442 443 if (allockva && (error = pipespace(cpipe, PIPE_SIZE))) 444 return (error); 445 446 vfs_timestamp(&cpipe->pipe_ctime); 447 cpipe->pipe_atime = cpipe->pipe_ctime; 448 cpipe->pipe_mtime = cpipe->pipe_ctime; 449 #ifdef __NetBSD__ 450 cpipe->pipe_pgid = NO_PID; 451 lockinit(&cpipe->pipe_lock, PRIBIO | PCATCH, "pipelk", 0, 0); 452 #endif 453 454 return (0); 455 } 456 457 458 /* 459 * lock a pipe for I/O, blocking other access 460 */ 461 static __inline int 462 pipelock(cpipe, catch) 463 struct pipe *cpipe; 464 int catch; 465 { 466 int error; 467 468 #ifdef __FreeBSD__ 469 while (cpipe->pipe_state & PIPE_LOCK) { 470 cpipe->pipe_state |= PIPE_LWANT; 471 error = tsleep(cpipe, catch ? (PRIBIO | PCATCH) : PRIBIO, 472 "pipelk", 0); 473 if (error != 0) 474 return (error); 475 } 476 cpipe->pipe_state |= PIPE_LOCK; 477 return (0); 478 #endif 479 480 #ifdef __NetBSD__ 481 do { 482 error = lockmgr(&cpipe->pipe_lock, LK_EXCLUSIVE, NULL); 483 } while (!catch && (error == EINTR || error == ERESTART)); 484 return (error); 485 #endif 486 } 487 488 /* 489 * unlock a pipe I/O lock 490 */ 491 static __inline void 492 pipeunlock(cpipe) 493 struct pipe *cpipe; 494 { 495 #ifdef __FreeBSD__ 496 cpipe->pipe_state &= ~PIPE_LOCK; 497 if (cpipe->pipe_state & PIPE_LWANT) { 498 cpipe->pipe_state &= ~PIPE_LWANT; 499 wakeup(cpipe); 500 } 501 #endif 502 503 #ifdef __NetBSD__ 504 lockmgr(&cpipe->pipe_lock, LK_RELEASE, NULL); 505 #endif 506 } 507 508 /* 509 * Select/poll wakup. This also sends SIGIO to peer connected to 510 * 'sigpipe' side of pipe. 511 */ 512 static __inline void 513 pipeselwakeup(selp, sigp) 514 struct pipe *selp, *sigp; 515 { 516 if (selp->pipe_state & PIPE_SEL) { 517 selp->pipe_state &= ~PIPE_SEL; 518 selwakeup(&selp->pipe_sel); 519 } 520 #ifdef __FreeBSD__ 521 if (sigp && (sigp->pipe_state & PIPE_ASYNC) && sigp->pipe_sigio) 522 pgsigio(sigp->pipe_sigio, SIGIO, 0); 523 KNOTE(&selp->pipe_sel.si_note, 0); 524 #endif 525 526 #ifdef __NetBSD__ 527 if (sigp && (sigp->pipe_state & PIPE_ASYNC) 528 && sigp->pipe_pgid != NO_PID){ 529 struct proc *p; 530 531 if (sigp->pipe_pgid < 0) 532 gsignal(-sigp->pipe_pgid, SIGIO); 533 else if (sigp->pipe_pgid > 0 && (p = pfind(sigp->pipe_pgid)) != 0) 534 psignal(p, SIGIO); 535 } 536 #endif /* NetBSD */ 537 } 538 539 /* ARGSUSED */ 540 #ifdef __FreeBSD__ 541 static int 542 pipe_read(fp, uio, cred, flags, p) 543 struct file *fp; 544 struct uio *uio; 545 struct ucred *cred; 546 int flags; 547 struct proc *p; 548 #elif defined(__NetBSD__) 549 static int 550 pipe_read(fp, offset, uio, cred, flags) 551 struct file *fp; 552 off_t *offset; 553 struct uio *uio; 554 struct ucred *cred; 555 int flags; 556 #endif 557 { 558 struct pipe *rpipe = (struct pipe *) fp->f_data; 559 int error; 560 size_t nread = 0; 561 size_t size; 562 size_t ocnt; 563 564 ++rpipe->pipe_busy; 565 error = pipelock(rpipe, 1); 566 if (error) 567 goto unlocked_error; 568 569 ocnt = rpipe->pipe_buffer.cnt; 570 571 while (uio->uio_resid) { 572 /* 573 * normal pipe buffer receive 574 */ 575 if (rpipe->pipe_buffer.cnt > 0) { 576 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 577 if (size > rpipe->pipe_buffer.cnt) 578 size = rpipe->pipe_buffer.cnt; 579 if (size > uio->uio_resid) 580 size = uio->uio_resid; 581 582 error = uiomove(&rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 583 size, uio); 584 if (error) 585 break; 586 587 rpipe->pipe_buffer.out += size; 588 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 589 rpipe->pipe_buffer.out = 0; 590 591 rpipe->pipe_buffer.cnt -= size; 592 593 /* 594 * If there is no more to read in the pipe, reset 595 * its pointers to the beginning. This improves 596 * cache hit stats. 597 */ 598 if (rpipe->pipe_buffer.cnt == 0) { 599 rpipe->pipe_buffer.in = 0; 600 rpipe->pipe_buffer.out = 0; 601 } 602 nread += size; 603 #ifndef PIPE_NODIRECT 604 /* 605 * Direct copy, bypassing a kernel buffer. 606 */ 607 } else if ((size = rpipe->pipe_map.cnt) && 608 (rpipe->pipe_state & PIPE_DIRECTW)) { 609 caddr_t va; 610 if (size > uio->uio_resid) 611 size = uio->uio_resid; 612 613 va = (caddr_t) rpipe->pipe_map.kva + 614 rpipe->pipe_map.pos; 615 error = uiomove(va, size, uio); 616 if (error) 617 break; 618 nread += size; 619 rpipe->pipe_map.pos += size; 620 rpipe->pipe_map.cnt -= size; 621 if (rpipe->pipe_map.cnt == 0) { 622 rpipe->pipe_state &= ~PIPE_DIRECTW; 623 wakeup(rpipe); 624 } 625 #endif 626 } else { 627 /* 628 * detect EOF condition 629 * read returns 0 on EOF, no need to set error 630 */ 631 if (rpipe->pipe_state & PIPE_EOF) 632 break; 633 634 /* 635 * If the "write-side" has been blocked, wake it up now. 636 */ 637 if (rpipe->pipe_state & PIPE_WANTW) { 638 rpipe->pipe_state &= ~PIPE_WANTW; 639 wakeup(rpipe); 640 } 641 642 /* 643 * Break if some data was read. 644 */ 645 if (nread > 0) 646 break; 647 648 /* 649 * don't block on non-blocking I/O 650 */ 651 if (fp->f_flag & FNONBLOCK) { 652 error = EAGAIN; 653 break; 654 } 655 656 /* 657 * Unlock the pipe buffer for our remaining processing. 658 * We will either break out with an error or we will 659 * sleep and relock to loop. 660 */ 661 pipeunlock(rpipe); 662 663 /* 664 * We want to read more, wake up select/poll. 665 */ 666 pipeselwakeup(rpipe, rpipe->pipe_peer); 667 668 rpipe->pipe_state |= PIPE_WANTR; 669 error = tsleep(rpipe, PRIBIO | PCATCH, "piperd", 0); 670 if (error != 0 || (error = pipelock(rpipe, 1))) 671 goto unlocked_error; 672 } 673 } 674 pipeunlock(rpipe); 675 676 if (error == 0) 677 vfs_timestamp(&rpipe->pipe_atime); 678 unlocked_error: 679 --rpipe->pipe_busy; 680 681 /* 682 * PIPE_WANTCLOSE processing only makes sense if pipe_busy is 0. 683 */ 684 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANTCLOSE)) { 685 rpipe->pipe_state &= ~(PIPE_WANTCLOSE|PIPE_WANTW); 686 wakeup(rpipe); 687 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 688 /* 689 * Handle write blocking hysteresis. 690 */ 691 if (rpipe->pipe_state & PIPE_WANTW) { 692 rpipe->pipe_state &= ~PIPE_WANTW; 693 wakeup(rpipe); 694 } 695 } 696 697 /* 698 * If anything was read off the buffer, signal to the writer it's 699 * possible to write more data. Also send signal if we are here for the 700 * first time after last write. 701 */ 702 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF 703 && (ocnt != rpipe->pipe_buffer.cnt || (rpipe->pipe_state & PIPE_SIGNALR))) { 704 pipeselwakeup(rpipe, rpipe->pipe_peer); 705 rpipe->pipe_state &= ~PIPE_SIGNALR; 706 } 707 708 return (error); 709 } 710 711 #ifdef __FreeBSD__ 712 #ifndef PIPE_NODIRECT 713 /* 714 * Map the sending processes' buffer into kernel space and wire it. 715 * This is similar to a physical write operation. 716 */ 717 static int 718 pipe_build_write_buffer(wpipe, uio) 719 struct pipe *wpipe; 720 struct uio *uio; 721 { 722 size_t size; 723 int i; 724 vm_offset_t addr, endaddr, paddr; 725 726 size = uio->uio_iov->iov_len; 727 if (size > wpipe->pipe_buffer.size) 728 size = wpipe->pipe_buffer.size; 729 730 endaddr = round_page((vm_offset_t)uio->uio_iov->iov_base + size); 731 mtx_lock(&vm_mtx); 732 addr = trunc_page((vm_offset_t)uio->uio_iov->iov_base); 733 for (i = 0; addr < endaddr; addr += PAGE_SIZE, i++) { 734 vm_page_t m; 735 736 if (vm_fault_quick((caddr_t)addr, VM_PROT_READ) < 0 || 737 (paddr = pmap_kextract(addr)) == 0) { 738 int j; 739 740 for (j = 0; j < i; j++) 741 vm_page_unwire(wpipe->pipe_map.ms[j], 1); 742 mtx_unlock(&vm_mtx); 743 return (EFAULT); 744 } 745 746 m = PHYS_TO_VM_PAGE(paddr); 747 vm_page_wire(m); 748 wpipe->pipe_map.ms[i] = m; 749 } 750 751 /* 752 * set up the control block 753 */ 754 wpipe->pipe_map.npages = i; 755 wpipe->pipe_map.pos = 756 ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; 757 wpipe->pipe_map.cnt = size; 758 759 /* 760 * and map the buffer 761 */ 762 if (wpipe->pipe_map.kva == 0) { 763 /* 764 * We need to allocate space for an extra page because the 765 * address range might (will) span pages at times. 766 */ 767 wpipe->pipe_map.kva = kmem_alloc_pageable(kernel_map, 768 wpipe->pipe_buffer.size + PAGE_SIZE); 769 amountpipekva += wpipe->pipe_buffer.size + PAGE_SIZE; 770 } 771 pmap_qenter(wpipe->pipe_map.kva, wpipe->pipe_map.ms, 772 wpipe->pipe_map.npages); 773 774 mtx_unlock(&vm_mtx); 775 /* 776 * and update the uio data 777 */ 778 779 uio->uio_iov->iov_len -= size; 780 uio->uio_iov->iov_base += size; 781 if (uio->uio_iov->iov_len == 0) 782 uio->uio_iov++; 783 uio->uio_resid -= size; 784 uio->uio_offset += size; 785 return (0); 786 } 787 788 /* 789 * unmap and unwire the process buffer 790 */ 791 static void 792 pipe_destroy_write_buffer(wpipe) 793 struct pipe *wpipe; 794 { 795 int i; 796 797 mtx_lock(&vm_mtx); 798 if (wpipe->pipe_map.kva) { 799 pmap_qremove(wpipe->pipe_map.kva, wpipe->pipe_map.npages); 800 801 if (amountpipekva > maxpipekva) { 802 vm_offset_t kva = wpipe->pipe_map.kva; 803 wpipe->pipe_map.kva = 0; 804 kmem_free(kernel_map, kva, 805 wpipe->pipe_buffer.size + PAGE_SIZE); 806 amountpipekva -= wpipe->pipe_buffer.size + PAGE_SIZE; 807 } 808 } 809 for (i = 0; i < wpipe->pipe_map.npages; i++) 810 vm_page_unwire(wpipe->pipe_map.ms[i], 1); 811 mtx_unlock(&vm_mtx); 812 } 813 814 /* 815 * In the case of a signal, the writing process might go away. This 816 * code copies the data into the circular buffer so that the source 817 * pages can be freed without loss of data. 818 */ 819 static void 820 pipe_clone_write_buffer(wpipe) 821 struct pipe *wpipe; 822 { 823 int size; 824 int pos; 825 826 size = wpipe->pipe_map.cnt; 827 pos = wpipe->pipe_map.pos; 828 memcpy((caddr_t) wpipe->pipe_buffer.buffer, 829 (caddr_t) wpipe->pipe_map.kva + pos, size); 830 831 wpipe->pipe_buffer.in = size; 832 wpipe->pipe_buffer.out = 0; 833 wpipe->pipe_buffer.cnt = size; 834 wpipe->pipe_state &= ~PIPE_DIRECTW; 835 836 pipe_destroy_write_buffer(wpipe); 837 } 838 839 /* 840 * This implements the pipe buffer write mechanism. Note that only 841 * a direct write OR a normal pipe write can be pending at any given time. 842 * If there are any characters in the pipe buffer, the direct write will 843 * be deferred until the receiving process grabs all of the bytes from 844 * the pipe buffer. Then the direct mapping write is set-up. 845 */ 846 static int 847 pipe_direct_write(wpipe, uio) 848 struct pipe *wpipe; 849 struct uio *uio; 850 { 851 int error; 852 853 retry: 854 while (wpipe->pipe_state & PIPE_DIRECTW) { 855 if (wpipe->pipe_state & PIPE_WANTR) { 856 wpipe->pipe_state &= ~PIPE_WANTR; 857 wakeup(wpipe); 858 } 859 wpipe->pipe_state |= PIPE_WANTW; 860 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdww", 0); 861 if (error) 862 goto error1; 863 if (wpipe->pipe_state & PIPE_EOF) { 864 error = EPIPE; 865 goto error1; 866 } 867 } 868 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 869 if (wpipe->pipe_buffer.cnt > 0) { 870 if (wpipe->pipe_state & PIPE_WANTR) { 871 wpipe->pipe_state &= ~PIPE_WANTR; 872 wakeup(wpipe); 873 } 874 875 wpipe->pipe_state |= PIPE_WANTW; 876 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdwc", 0); 877 if (error) 878 goto error1; 879 if (wpipe->pipe_state & PIPE_EOF) { 880 error = EPIPE; 881 goto error1; 882 } 883 goto retry; 884 } 885 886 wpipe->pipe_state |= PIPE_DIRECTW; 887 888 error = pipe_build_write_buffer(wpipe, uio); 889 if (error) { 890 wpipe->pipe_state &= ~PIPE_DIRECTW; 891 goto error1; 892 } 893 894 error = 0; 895 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 896 if (wpipe->pipe_state & PIPE_EOF) { 897 pipelock(wpipe, 0); 898 pipe_destroy_write_buffer(wpipe); 899 pipeunlock(wpipe); 900 pipeselwakeup(wpipe, wpipe); 901 error = EPIPE; 902 goto error1; 903 } 904 if (wpipe->pipe_state & PIPE_WANTR) { 905 wpipe->pipe_state &= ~PIPE_WANTR; 906 wakeup(wpipe); 907 } 908 pipeselwakeup(wpipe, wpipe); 909 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdwt", 0); 910 } 911 912 pipelock(wpipe,0); 913 if (wpipe->pipe_state & PIPE_DIRECTW) { 914 /* 915 * this bit of trickery substitutes a kernel buffer for 916 * the process that might be going away. 917 */ 918 pipe_clone_write_buffer(wpipe); 919 } else { 920 pipe_destroy_write_buffer(wpipe); 921 } 922 pipeunlock(wpipe); 923 return (error); 924 925 error1: 926 wakeup(wpipe); 927 return (error); 928 } 929 #endif /* !PIPE_NODIRECT */ 930 #endif /* FreeBSD */ 931 932 #ifdef __NetBSD__ 933 #ifndef PIPE_NODIRECT 934 /* 935 * Allocate structure for loan transfer. 936 */ 937 static int 938 pipe_loan_alloc(wpipe, npages) 939 struct pipe *wpipe; 940 int npages; 941 { 942 vsize_t len; 943 944 len = (vsize_t)npages << PAGE_SHIFT; 945 wpipe->pipe_map.kva = uvm_km_valloc_wait(kernel_map, len); 946 if (wpipe->pipe_map.kva == NULL) 947 return (ENOMEM); 948 949 amountpipekva += len; 950 wpipe->pipe_map.npages = npages; 951 wpipe->pipe_map.pgs = malloc(npages * sizeof(struct vm_page *), M_PIPE, 952 M_WAITOK); 953 return (0); 954 } 955 956 /* 957 * Free resources allocated for loan transfer. 958 */ 959 static void 960 pipe_loan_free(wpipe) 961 struct pipe *wpipe; 962 { 963 vsize_t len; 964 965 len = (vsize_t)wpipe->pipe_map.npages << PAGE_SHIFT; 966 pmap_kremove(wpipe->pipe_map.kva, len); 967 uvm_km_free(kernel_map, wpipe->pipe_map.kva, len); 968 wpipe->pipe_map.kva = NULL; 969 amountpipekva -= len; 970 free(wpipe->pipe_map.pgs, M_PIPE); 971 wpipe->pipe_map.pgs = NULL; 972 } 973 974 /* 975 * NetBSD direct write, using uvm_loan() mechanism. 976 * This implements the pipe buffer write mechanism. Note that only 977 * a direct write OR a normal pipe write can be pending at any given time. 978 * If there are any characters in the pipe buffer, the direct write will 979 * be deferred until the receiving process grabs all of the bytes from 980 * the pipe buffer. Then the direct mapping write is set-up. 981 */ 982 static int 983 pipe_direct_write(wpipe, uio) 984 struct pipe *wpipe; 985 struct uio *uio; 986 { 987 int error, npages, j; 988 struct vm_page **pgs; 989 vaddr_t bbase, kva, base, bend; 990 vsize_t blen, bcnt; 991 voff_t bpos; 992 993 retry: 994 while (wpipe->pipe_state & PIPE_DIRECTW) { 995 if (wpipe->pipe_state & PIPE_WANTR) { 996 wpipe->pipe_state &= ~PIPE_WANTR; 997 wakeup(wpipe); 998 } 999 wpipe->pipe_state |= PIPE_WANTW; 1000 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdww", 0); 1001 if (error) 1002 goto error; 1003 if (wpipe->pipe_state & PIPE_EOF) { 1004 error = EPIPE; 1005 goto error; 1006 } 1007 } 1008 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 1009 if (wpipe->pipe_buffer.cnt > 0) { 1010 if (wpipe->pipe_state & PIPE_WANTR) { 1011 wpipe->pipe_state &= ~PIPE_WANTR; 1012 wakeup(wpipe); 1013 } 1014 1015 wpipe->pipe_state |= PIPE_WANTW; 1016 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdwc", 0); 1017 if (error) 1018 goto error; 1019 if (wpipe->pipe_state & PIPE_EOF) { 1020 error = EPIPE; 1021 goto error; 1022 } 1023 goto retry; 1024 } 1025 1026 /* 1027 * Handle first PIPE_CHUNK_SIZE bytes of buffer. Deal with buffers 1028 * not aligned to PAGE_SIZE. 1029 */ 1030 bbase = (vaddr_t)uio->uio_iov->iov_base; 1031 base = trunc_page(bbase); 1032 bend = round_page(bbase + uio->uio_iov->iov_len); 1033 blen = bend - base; 1034 bpos = bbase - base; 1035 1036 if (blen > PIPE_DIRECT_CHUNK) { 1037 blen = PIPE_DIRECT_CHUNK; 1038 bend = base + blen; 1039 bcnt = PIPE_DIRECT_CHUNK - bpos; 1040 } else { 1041 bcnt = uio->uio_iov->iov_len; 1042 } 1043 npages = blen >> PAGE_SHIFT; 1044 1045 wpipe->pipe_map.pos = bpos; 1046 wpipe->pipe_map.cnt = bcnt; 1047 1048 /* 1049 * Free the old kva if we need more pages than we have 1050 * allocated. 1051 */ 1052 if (wpipe->pipe_map.kva && npages > wpipe->pipe_map.npages) 1053 pipe_loan_free(wpipe); 1054 1055 /* Allocate new kva. */ 1056 if (wpipe->pipe_map.kva == NULL) { 1057 error = pipe_loan_alloc(wpipe, npages); 1058 if (error) { 1059 goto error; 1060 } 1061 } 1062 1063 /* Loan the write buffer memory from writer process */ 1064 pgs = wpipe->pipe_map.pgs; 1065 error = uvm_loan(&uio->uio_procp->p_vmspace->vm_map, base, blen, 1066 pgs, UVM_LOAN_TOPAGE); 1067 if (error) { 1068 pgs = NULL; 1069 goto cleanup; 1070 } 1071 1072 /* Enter the loaned pages to kva */ 1073 kva = wpipe->pipe_map.kva; 1074 for (j = 0; j < npages; j++, kva += PAGE_SIZE) { 1075 pmap_kenter_pa(kva, VM_PAGE_TO_PHYS(pgs[j]), VM_PROT_READ); 1076 } 1077 pmap_update(pmap_kernel()); 1078 1079 wpipe->pipe_state |= PIPE_DIRECTW; 1080 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 1081 if (wpipe->pipe_state & PIPE_EOF) { 1082 error = EPIPE; 1083 break; 1084 } 1085 if (wpipe->pipe_state & PIPE_WANTR) { 1086 wpipe->pipe_state &= ~PIPE_WANTR; 1087 wakeup(wpipe); 1088 } 1089 pipeselwakeup(wpipe, wpipe); 1090 error = tsleep(wpipe, PRIBIO | PCATCH, "pipdwt", 0); 1091 } 1092 1093 if (error) 1094 wpipe->pipe_state &= ~PIPE_DIRECTW; 1095 1096 cleanup: 1097 pipelock(wpipe, 0); 1098 if (pgs != NULL) 1099 uvm_unloan(pgs, npages, UVM_LOAN_TOPAGE); 1100 if (error || amountpipekva > maxpipekva) 1101 pipe_loan_free(wpipe); 1102 pipeunlock(wpipe); 1103 1104 if (error) { 1105 pipeselwakeup(wpipe, wpipe); 1106 1107 /* 1108 * If nothing was read from what we offered, return error 1109 * straight on. Otherwise update uio resid first. Caller 1110 * will deal with the error condition, returning short 1111 * write, error, or restarting the write(2) as appropriate. 1112 */ 1113 if (wpipe->pipe_map.cnt == bcnt) { 1114 error: 1115 wakeup(wpipe); 1116 return (error); 1117 } 1118 1119 bcnt -= wpipe->pipe_map.cnt; 1120 } 1121 1122 uio->uio_resid -= bcnt; 1123 /* uio_offset not updated, not set/used for write(2) */ 1124 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + bcnt; 1125 uio->uio_iov->iov_len -= bcnt; 1126 if (uio->uio_iov->iov_len == 0) { 1127 uio->uio_iov++; 1128 uio->uio_iovcnt--; 1129 } 1130 1131 return (error); 1132 } 1133 #endif /* !PIPE_NODIRECT */ 1134 #endif /* NetBSD */ 1135 1136 #ifdef __FreeBSD__ 1137 static int 1138 pipe_write(fp, uio, cred, flags, p) 1139 struct file *fp; 1140 off_t *offset; 1141 struct uio *uio; 1142 struct ucred *cred; 1143 int flags; 1144 struct proc *p; 1145 #elif defined(__NetBSD__) 1146 static int 1147 pipe_write(fp, offset, uio, cred, flags) 1148 struct file *fp; 1149 off_t *offset; 1150 struct uio *uio; 1151 struct ucred *cred; 1152 int flags; 1153 #endif 1154 { 1155 int error = 0; 1156 struct pipe *wpipe, *rpipe; 1157 1158 rpipe = (struct pipe *) fp->f_data; 1159 wpipe = rpipe->pipe_peer; 1160 1161 /* 1162 * detect loss of pipe read side, issue SIGPIPE if lost. 1163 */ 1164 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) 1165 return (EPIPE); 1166 1167 ++wpipe->pipe_busy; 1168 1169 /* 1170 * If it is advantageous to resize the pipe buffer, do 1171 * so. 1172 */ 1173 if ((uio->uio_resid > PIPE_SIZE) && 1174 (nbigpipe < maxbigpipes) && 1175 #ifndef PIPE_NODIRECT 1176 (wpipe->pipe_state & PIPE_DIRECTW) == 0 && 1177 #endif 1178 (wpipe->pipe_buffer.size <= PIPE_SIZE) && 1179 (wpipe->pipe_buffer.cnt == 0)) { 1180 1181 if ((error = pipelock(wpipe,1)) == 0) { 1182 if (pipespace(wpipe, BIG_PIPE_SIZE) == 0) 1183 nbigpipe++; 1184 pipeunlock(wpipe); 1185 } else { 1186 /* 1187 * If an error occurred, unbusy and return, waking up 1188 * any waiting readers. 1189 */ 1190 --wpipe->pipe_busy; 1191 if (wpipe->pipe_busy == 0 1192 && (wpipe->pipe_state & PIPE_WANTCLOSE)) { 1193 wpipe->pipe_state &= 1194 ~(PIPE_WANTCLOSE | PIPE_WANTR); 1195 wakeup(wpipe); 1196 } 1197 1198 return (error); 1199 } 1200 } 1201 1202 #ifdef __FreeBSD__ 1203 KASSERT(wpipe->pipe_buffer.buffer != NULL, ("pipe buffer gone")); 1204 #endif 1205 1206 while (uio->uio_resid) { 1207 int space; 1208 1209 #ifndef PIPE_NODIRECT 1210 /* 1211 * If the transfer is large, we can gain performance if 1212 * we do process-to-process copies directly. 1213 * If the write is non-blocking, we don't use the 1214 * direct write mechanism. 1215 * 1216 * The direct write mechanism will detect the reader going 1217 * away on us. 1218 */ 1219 if ((uio->uio_iov->iov_len >= PIPE_MINDIRECT) && 1220 (fp->f_flag & FNONBLOCK) == 0 && 1221 (wpipe->pipe_map.kva || (amountpipekva < limitpipekva))) { 1222 error = pipe_direct_write(wpipe, uio); 1223 1224 /* 1225 * Break out if error occured, unless it's ENOMEM. 1226 * ENOMEM means we failed to allocate some resources 1227 * for direct write, so we just fallback to ordinary 1228 * write. If the direct write was successful, 1229 * process rest of data via ordinary write. 1230 */ 1231 if (!error) 1232 continue; 1233 1234 if (error != ENOMEM) 1235 break; 1236 } 1237 #endif /* PIPE_NODIRECT */ 1238 1239 /* 1240 * Pipe buffered writes cannot be coincidental with 1241 * direct writes. We wait until the currently executing 1242 * direct write is completed before we start filling the 1243 * pipe buffer. We break out if a signal occurs or the 1244 * reader goes away. 1245 */ 1246 retrywrite: 1247 while (wpipe->pipe_state & PIPE_DIRECTW) { 1248 if (wpipe->pipe_state & PIPE_WANTR) { 1249 wpipe->pipe_state &= ~PIPE_WANTR; 1250 wakeup(wpipe); 1251 } 1252 error = tsleep(wpipe, PRIBIO | PCATCH, "pipbww", 0); 1253 if (wpipe->pipe_state & PIPE_EOF) 1254 break; 1255 if (error) 1256 break; 1257 } 1258 if (wpipe->pipe_state & PIPE_EOF) { 1259 error = EPIPE; 1260 break; 1261 } 1262 1263 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1264 1265 /* Writes of size <= PIPE_BUF must be atomic. */ 1266 if ((space < uio->uio_resid) && (uio->uio_resid <= PIPE_BUF)) 1267 space = 0; 1268 1269 if (space > 0) { 1270 int size; /* Transfer size */ 1271 int segsize; /* first segment to transfer */ 1272 1273 if ((error = pipelock(wpipe,1)) != 0) 1274 break; 1275 1276 /* 1277 * It is possible for a direct write to 1278 * slip in on us... handle it here... 1279 */ 1280 if (wpipe->pipe_state & PIPE_DIRECTW) { 1281 pipeunlock(wpipe); 1282 goto retrywrite; 1283 } 1284 /* 1285 * If a process blocked in uiomove, our 1286 * value for space might be bad. 1287 * 1288 * XXX will we be ok if the reader has gone 1289 * away here? 1290 */ 1291 if (space > wpipe->pipe_buffer.size - 1292 wpipe->pipe_buffer.cnt) { 1293 pipeunlock(wpipe); 1294 goto retrywrite; 1295 } 1296 1297 /* 1298 * Transfer size is minimum of uio transfer 1299 * and free space in pipe buffer. 1300 */ 1301 if (space > uio->uio_resid) 1302 size = uio->uio_resid; 1303 else 1304 size = space; 1305 /* 1306 * First segment to transfer is minimum of 1307 * transfer size and contiguous space in 1308 * pipe buffer. If first segment to transfer 1309 * is less than the transfer size, we've got 1310 * a wraparound in the buffer. 1311 */ 1312 segsize = wpipe->pipe_buffer.size - 1313 wpipe->pipe_buffer.in; 1314 if (segsize > size) 1315 segsize = size; 1316 1317 /* Transfer first segment */ 1318 1319 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1320 segsize, uio); 1321 1322 if (error == 0 && segsize < size) { 1323 /* 1324 * Transfer remaining part now, to 1325 * support atomic writes. Wraparound 1326 * happened. 1327 */ 1328 #ifdef DEBUG 1329 if (wpipe->pipe_buffer.in + segsize != 1330 wpipe->pipe_buffer.size) 1331 panic("Expected pipe buffer wraparound disappeared"); 1332 #endif 1333 1334 error = uiomove(&wpipe->pipe_buffer.buffer[0], 1335 size - segsize, uio); 1336 } 1337 if (error == 0) { 1338 wpipe->pipe_buffer.in += size; 1339 if (wpipe->pipe_buffer.in >= 1340 wpipe->pipe_buffer.size) { 1341 #ifdef DEBUG 1342 if (wpipe->pipe_buffer.in != size - segsize + wpipe->pipe_buffer.size) 1343 panic("Expected wraparound bad"); 1344 #endif 1345 wpipe->pipe_buffer.in = size - segsize; 1346 } 1347 1348 wpipe->pipe_buffer.cnt += size; 1349 #ifdef DEBUG 1350 if (wpipe->pipe_buffer.cnt > wpipe->pipe_buffer.size) 1351 panic("Pipe buffer overflow"); 1352 #endif 1353 } 1354 pipeunlock(wpipe); 1355 if (error) 1356 break; 1357 } else { 1358 /* 1359 * If the "read-side" has been blocked, wake it up now. 1360 */ 1361 if (wpipe->pipe_state & PIPE_WANTR) { 1362 wpipe->pipe_state &= ~PIPE_WANTR; 1363 wakeup(wpipe); 1364 } 1365 1366 /* 1367 * don't block on non-blocking I/O 1368 */ 1369 if (fp->f_flag & FNONBLOCK) { 1370 error = EAGAIN; 1371 break; 1372 } 1373 1374 /* 1375 * We have no more space and have something to offer, 1376 * wake up select/poll. 1377 */ 1378 pipeselwakeup(wpipe, wpipe); 1379 1380 wpipe->pipe_state |= PIPE_WANTW; 1381 error = tsleep(wpipe, PRIBIO | PCATCH, "pipewr", 0); 1382 if (error != 0) 1383 break; 1384 /* 1385 * If read side wants to go away, we just issue a signal 1386 * to ourselves. 1387 */ 1388 if (wpipe->pipe_state & PIPE_EOF) { 1389 error = EPIPE; 1390 break; 1391 } 1392 } 1393 } 1394 1395 --wpipe->pipe_busy; 1396 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANTCLOSE)) { 1397 wpipe->pipe_state &= ~(PIPE_WANTCLOSE | PIPE_WANTR); 1398 wakeup(wpipe); 1399 } else if (wpipe->pipe_buffer.cnt > 0) { 1400 /* 1401 * If we have put any characters in the buffer, we wake up 1402 * the reader. 1403 */ 1404 if (wpipe->pipe_state & PIPE_WANTR) { 1405 wpipe->pipe_state &= ~PIPE_WANTR; 1406 wakeup(wpipe); 1407 } 1408 } 1409 1410 /* 1411 * Don't return EPIPE if I/O was successful 1412 */ 1413 if ((error == EPIPE) && (wpipe->pipe_buffer.cnt == 0) 1414 && (uio->uio_resid == 0)) 1415 error = 0; 1416 1417 if (error == 0) 1418 vfs_timestamp(&wpipe->pipe_mtime); 1419 1420 /* 1421 * We have something to offer, wake up select/poll. 1422 * wpipe->pipe_map.cnt is always 0 in this point (direct write 1423 * is only done synchronously), so check only wpipe->pipe_buffer.cnt 1424 */ 1425 if (wpipe->pipe_buffer.cnt) 1426 pipeselwakeup(wpipe, wpipe); 1427 1428 /* 1429 * Arrange for next read(2) to do a signal. 1430 */ 1431 wpipe->pipe_state |= PIPE_SIGNALR; 1432 1433 return (error); 1434 } 1435 1436 /* 1437 * we implement a very minimal set of ioctls for compatibility with sockets. 1438 */ 1439 int 1440 pipe_ioctl(fp, cmd, data, p) 1441 struct file *fp; 1442 u_long cmd; 1443 caddr_t data; 1444 struct proc *p; 1445 { 1446 struct pipe *mpipe = (struct pipe *)fp->f_data; 1447 1448 switch (cmd) { 1449 1450 case FIONBIO: 1451 return (0); 1452 1453 case FIOASYNC: 1454 if (*(int *)data) { 1455 mpipe->pipe_state |= PIPE_ASYNC; 1456 } else { 1457 mpipe->pipe_state &= ~PIPE_ASYNC; 1458 } 1459 return (0); 1460 1461 case FIONREAD: 1462 #ifndef PIPE_NODIRECT 1463 if (mpipe->pipe_state & PIPE_DIRECTW) 1464 *(int *)data = mpipe->pipe_map.cnt; 1465 else 1466 #endif 1467 *(int *)data = mpipe->pipe_buffer.cnt; 1468 return (0); 1469 1470 #ifdef __FreeBSD__ 1471 case FIOSETOWN: 1472 return (fsetown(*(int *)data, &mpipe->pipe_sigio)); 1473 1474 case FIOGETOWN: 1475 *(int *)data = fgetown(mpipe->pipe_sigio); 1476 return (0); 1477 1478 /* This is deprecated, FIOSETOWN should be used instead. */ 1479 case TIOCSPGRP: 1480 return (fsetown(-(*(int *)data), &mpipe->pipe_sigio)); 1481 1482 /* This is deprecated, FIOGETOWN should be used instead. */ 1483 case TIOCGPGRP: 1484 *(int *)data = -fgetown(mpipe->pipe_sigio); 1485 return (0); 1486 #endif /* FreeBSD */ 1487 #ifdef __NetBSD__ 1488 case TIOCSPGRP: 1489 mpipe->pipe_pgid = *(int *)data; 1490 return (0); 1491 1492 case TIOCGPGRP: 1493 *(int *)data = mpipe->pipe_pgid; 1494 return (0); 1495 #endif /* NetBSD */ 1496 1497 } 1498 return (ENOTTY); 1499 } 1500 1501 int 1502 pipe_poll(fp, events, p) 1503 struct file *fp; 1504 int events; 1505 struct proc *p; 1506 { 1507 struct pipe *rpipe = (struct pipe *)fp->f_data; 1508 struct pipe *wpipe; 1509 int revents = 0; 1510 1511 wpipe = rpipe->pipe_peer; 1512 if (events & (POLLIN | POLLRDNORM)) 1513 if ((rpipe->pipe_buffer.cnt > 0) || 1514 #ifndef PIPE_NODIRECT 1515 (rpipe->pipe_state & PIPE_DIRECTW) || 1516 #endif 1517 (rpipe->pipe_state & PIPE_EOF)) 1518 revents |= events & (POLLIN | POLLRDNORM); 1519 1520 if (events & (POLLOUT | POLLWRNORM)) 1521 if (wpipe == NULL || (wpipe->pipe_state & PIPE_EOF) 1522 || ( 1523 #ifndef PIPE_NODIRECT 1524 ((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1525 #endif 1526 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF)) 1527 revents |= events & (POLLOUT | POLLWRNORM); 1528 1529 if ((rpipe->pipe_state & PIPE_EOF) || 1530 (wpipe == NULL) || 1531 (wpipe->pipe_state & PIPE_EOF)) 1532 revents |= POLLHUP; 1533 1534 if (revents == 0) { 1535 if (events & (POLLIN | POLLRDNORM)) { 1536 selrecord(p, &rpipe->pipe_sel); 1537 rpipe->pipe_state |= PIPE_SEL; 1538 } 1539 1540 if (events & (POLLOUT | POLLWRNORM)) { 1541 selrecord(p, &wpipe->pipe_sel); 1542 wpipe->pipe_state |= PIPE_SEL; 1543 } 1544 } 1545 1546 return (revents); 1547 } 1548 1549 static int 1550 pipe_stat(fp, ub, p) 1551 struct file *fp; 1552 struct stat *ub; 1553 struct proc *p; 1554 { 1555 struct pipe *pipe = (struct pipe *)fp->f_data; 1556 1557 memset((caddr_t)ub, 0, sizeof(*ub)); 1558 ub->st_mode = S_IFIFO; 1559 ub->st_blksize = pipe->pipe_buffer.size; 1560 ub->st_size = pipe->pipe_buffer.cnt; 1561 ub->st_blocks = (ub->st_size) ? 1 : 0; 1562 #ifdef __FreeBSD__ 1563 ub->st_atimespec = pipe->pipe_atime; 1564 ub->st_mtimespec = pipe->pipe_mtime; 1565 ub->st_ctimespec = pipe->pipe_ctime; 1566 #endif /* FreeBSD */ 1567 #ifdef __NetBSD__ 1568 TIMEVAL_TO_TIMESPEC(&pipe->pipe_atime, &ub->st_atimespec) 1569 TIMEVAL_TO_TIMESPEC(&pipe->pipe_mtime, &ub->st_mtimespec); 1570 TIMEVAL_TO_TIMESPEC(&pipe->pipe_ctime, &ub->st_ctimespec); 1571 #endif /* NetBSD */ 1572 ub->st_uid = fp->f_cred->cr_uid; 1573 ub->st_gid = fp->f_cred->cr_gid; 1574 /* 1575 * Left as 0: st_dev, st_ino, st_nlink, st_rdev, st_flags, st_gen. 1576 * XXX (st_dev, st_ino) should be unique. 1577 */ 1578 return (0); 1579 } 1580 1581 /* ARGSUSED */ 1582 static int 1583 pipe_close(fp, p) 1584 struct file *fp; 1585 struct proc *p; 1586 { 1587 struct pipe *cpipe = (struct pipe *)fp->f_data; 1588 1589 #ifdef __FreeBSD__ 1590 fp->f_ops = &badfileops; 1591 funsetown(cpipe->pipe_sigio); 1592 #endif 1593 fp->f_data = NULL; 1594 pipeclose(cpipe); 1595 return (0); 1596 } 1597 1598 static void 1599 pipe_free_kmem(cpipe) 1600 struct pipe *cpipe; 1601 { 1602 1603 #ifdef __FreeBSD__ 1604 mtx_assert(&vm_mtx, MA_OWNED); 1605 #endif 1606 if (cpipe->pipe_buffer.buffer != NULL) { 1607 if (cpipe->pipe_buffer.size > PIPE_SIZE) 1608 --nbigpipe; 1609 amountpipekva -= cpipe->pipe_buffer.size; 1610 #ifdef __FreeBSD__ 1611 kmem_free(kernel_map, 1612 (vm_offset_t)cpipe->pipe_buffer.buffer, 1613 cpipe->pipe_buffer.size); 1614 #elif defined(__NetBSD__) 1615 uvm_km_free(kernel_map, 1616 (vaddr_t)cpipe->pipe_buffer.buffer, 1617 cpipe->pipe_buffer.size); 1618 #endif /* NetBSD */ 1619 cpipe->pipe_buffer.buffer = NULL; 1620 } 1621 #ifndef PIPE_NODIRECT 1622 if (cpipe->pipe_map.kva != NULL) { 1623 #ifdef __FreeBSD__ 1624 amountpipekva -= cpipe->pipe_buffer.size + PAGE_SIZE; 1625 kmem_free(kernel_map, 1626 cpipe->pipe_map.kva, 1627 cpipe->pipe_buffer.size + PAGE_SIZE); 1628 #elif defined(__NetBSD__) 1629 pipe_loan_free(cpipe); 1630 #endif /* NetBSD */ 1631 cpipe->pipe_map.cnt = 0; 1632 cpipe->pipe_map.kva = NULL; 1633 cpipe->pipe_map.pos = 0; 1634 cpipe->pipe_map.npages = 0; 1635 } 1636 #endif /* !PIPE_NODIRECT */ 1637 } 1638 1639 /* 1640 * shutdown the pipe 1641 */ 1642 static void 1643 pipeclose(cpipe) 1644 struct pipe *cpipe; 1645 { 1646 struct pipe *ppipe; 1647 1648 if (!cpipe) 1649 return; 1650 1651 pipeselwakeup(cpipe, cpipe); 1652 1653 /* 1654 * If the other side is blocked, wake it up saying that 1655 * we want to close it down. 1656 */ 1657 while (cpipe->pipe_busy) { 1658 wakeup(cpipe); 1659 cpipe->pipe_state |= PIPE_WANTCLOSE | PIPE_EOF; 1660 tsleep(cpipe, PRIBIO, "pipecl", 0); 1661 } 1662 1663 /* 1664 * Disconnect from peer 1665 */ 1666 if ((ppipe = cpipe->pipe_peer) != NULL) { 1667 pipeselwakeup(ppipe, ppipe); 1668 1669 ppipe->pipe_state |= PIPE_EOF; 1670 wakeup(ppipe); 1671 ppipe->pipe_peer = NULL; 1672 } 1673 1674 /* 1675 * free resources 1676 */ 1677 #ifdef __FreeBSD__ 1678 mtx_lock(&vm_mtx); 1679 pipe_free_kmem(cpipe); 1680 /* XXX: erm, doesn't zalloc already have its own locks and 1681 * not need the giant vm lock? 1682 */ 1683 zfree(pipe_zone, cpipe); 1684 mtx_unlock(&vm_mtx); 1685 #endif /* FreeBSD */ 1686 1687 #ifdef __NetBSD__ 1688 pipe_free_kmem(cpipe); 1689 (void) lockmgr(&cpipe->pipe_lock, LK_DRAIN, NULL); 1690 pool_put(&pipe_pool, cpipe); 1691 #endif 1692 } 1693 1694 #ifdef __FreeBSD__ 1695 /*ARGSUSED*/ 1696 static int 1697 pipe_kqfilter(struct file *fp, struct knote *kn) 1698 { 1699 struct pipe *cpipe = (struct pipe *)kn->kn_fp->f_data; 1700 1701 switch (kn->kn_filter) { 1702 case EVFILT_READ: 1703 kn->kn_fop = &pipe_rfiltops; 1704 break; 1705 case EVFILT_WRITE: 1706 kn->kn_fop = &pipe_wfiltops; 1707 cpipe = cpipe->pipe_peer; 1708 break; 1709 default: 1710 return (1); 1711 } 1712 kn->kn_hook = (caddr_t)cpipe; 1713 SLIST_INSERT_HEAD(&cpipe->pipe_sel.si_note, kn, kn_selnext); 1714 return (0); 1715 } 1716 1717 static void 1718 filt_pipedetach(struct knote *kn) 1719 { 1720 struct pipe *cpipe = (struct pipe *)kn->kn_fp->f_data; 1721 1722 SLIST_REMOVE(&cpipe->pipe_sel.si_note, kn, knote, kn_selnext); 1723 } 1724 1725 /*ARGSUSED*/ 1726 static int 1727 filt_piperead(struct knote *kn, long hint) 1728 { 1729 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1730 struct pipe *wpipe = rpipe->pipe_peer; 1731 1732 kn->kn_data = rpipe->pipe_buffer.cnt; 1733 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1734 kn->kn_data = rpipe->pipe_map.cnt; 1735 1736 if ((rpipe->pipe_state & PIPE_EOF) || 1737 (wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1738 kn->kn_flags |= EV_EOF; 1739 return (1); 1740 } 1741 return (kn->kn_data > 0); 1742 } 1743 1744 /*ARGSUSED*/ 1745 static int 1746 filt_pipewrite(struct knote *kn, long hint) 1747 { 1748 struct pipe *rpipe = (struct pipe *)kn->kn_fp->f_data; 1749 struct pipe *wpipe = rpipe->pipe_peer; 1750 1751 if ((wpipe == NULL) || (wpipe->pipe_state & PIPE_EOF)) { 1752 kn->kn_data = 0; 1753 kn->kn_flags |= EV_EOF; 1754 return (1); 1755 } 1756 kn->kn_data = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1757 if (wpipe->pipe_state & PIPE_DIRECTW) 1758 kn->kn_data = 0; 1759 1760 return (kn->kn_data >= PIPE_BUF); 1761 } 1762 #endif /* FreeBSD */ 1763 1764 #ifdef __NetBSD__ 1765 static int 1766 pipe_fcntl(fp, cmd, data, p) 1767 struct file *fp; 1768 u_int cmd; 1769 caddr_t data; 1770 struct proc *p; 1771 { 1772 if (cmd == F_SETFL) 1773 return (0); 1774 else 1775 return (EOPNOTSUPP); 1776 } 1777 1778 /* 1779 * Handle pipe sysctls. 1780 */ 1781 int 1782 sysctl_dopipe(name, namelen, oldp, oldlenp, newp, newlen) 1783 int *name; 1784 u_int namelen; 1785 void *oldp; 1786 size_t *oldlenp; 1787 void *newp; 1788 size_t newlen; 1789 { 1790 /* All sysctl names at this level are terminal. */ 1791 if (namelen != 1) 1792 return (ENOTDIR); /* overloaded */ 1793 1794 switch (name[0]) { 1795 case KERN_PIPE_MAXKVASZ: 1796 return (sysctl_int(oldp, oldlenp, newp, newlen, &maxpipekva)); 1797 case KERN_PIPE_LIMITKVA: 1798 return (sysctl_int(oldp, oldlenp, newp, newlen, &limitpipekva)); 1799 case KERN_PIPE_MAXBIGPIPES: 1800 return (sysctl_int(oldp, oldlenp, newp, newlen, &maxbigpipes)); 1801 case KERN_PIPE_NBIGPIPES: 1802 return (sysctl_rdint(oldp, oldlenp, newp, nbigpipe)); 1803 case KERN_PIPE_KVASIZE: 1804 return (sysctl_rdint(oldp, oldlenp, newp, amountpipekva)); 1805 default: 1806 return (EOPNOTSUPP); 1807 } 1808 /* NOTREACHED */ 1809 } 1810 1811 /* 1812 * Initialize pipe structs. 1813 */ 1814 void 1815 pipe_init(void) 1816 { 1817 pool_init(&pipe_pool, sizeof(struct pipe), 0, 0, 0, "pipepl", 1818 0, NULL, NULL, M_PIPE); 1819 } 1820 1821 #endif /* __NetBSD __ */ 1822