1 /*- 2 * Copyright (c) 1996 John S. Dyson 3 * Copyright (c) 2012 Giovanni Trematerra 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice immediately at the beginning of the file, without modification, 11 * this list of conditions, and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Absolutely no warranty of function or purpose is made by the author 16 * John S. Dyson. 17 * 4. Modifications may be freely made to this file if the above conditions 18 * are met. 19 */ 20 21 /* 22 * This file contains a high-performance replacement for the socket-based 23 * pipes scheme originally used in FreeBSD/4.4Lite. It does not support 24 * all features of sockets, but does do everything that pipes normally 25 * do. 26 */ 27 28 /* 29 * This code has two modes of operation, a small write mode and a large 30 * write mode. The small write mode acts like conventional pipes with 31 * a kernel buffer. If the buffer is less than PIPE_MINDIRECT, then the 32 * "normal" pipe buffering is done. If the buffer is between PIPE_MINDIRECT 33 * and PIPE_SIZE in size, the sending process pins the underlying pages in 34 * memory, and the receiving process copies directly from these pinned pages 35 * in the sending process. 36 * 37 * If the sending process receives a signal, it is possible that it will 38 * go away, and certainly its address space can change, because control 39 * is returned back to the user-mode side. In that case, the pipe code 40 * arranges to copy the buffer supplied by the user process, to a pageable 41 * kernel buffer, and the receiving process will grab the data from the 42 * pageable kernel buffer. Since signals don't happen all that often, 43 * the copy operation is normally eliminated. 44 * 45 * The constant PIPE_MINDIRECT is chosen to make sure that buffering will 46 * happen for small transfers so that the system will not spend all of 47 * its time context switching. 48 * 49 * In order to limit the resource use of pipes, two sysctls exist: 50 * 51 * kern.ipc.maxpipekva - This is a hard limit on the amount of pageable 52 * address space available to us in pipe_map. This value is normally 53 * autotuned, but may also be loader tuned. 54 * 55 * kern.ipc.pipekva - This read-only sysctl tracks the current amount of 56 * memory in use by pipes. 57 * 58 * Based on how large pipekva is relative to maxpipekva, the following 59 * will happen: 60 * 61 * 0% - 50%: 62 * New pipes are given 16K of memory backing, pipes may dynamically 63 * grow to as large as 64K where needed. 64 * 50% - 75%: 65 * New pipes are given 4K (or PAGE_SIZE) of memory backing, 66 * existing pipes may NOT grow. 67 * 75% - 100%: 68 * New pipes are given 4K (or PAGE_SIZE) of memory backing, 69 * existing pipes will be shrunk down to 4K whenever possible. 70 * 71 * Resizing may be disabled by setting kern.ipc.piperesizeallowed=0. If 72 * that is set, the only resize that will occur is the 0 -> SMALL_PIPE_SIZE 73 * resize which MUST occur for reverse-direction pipes when they are 74 * first used. 75 * 76 * Additional information about the current state of pipes may be obtained 77 * from kern.ipc.pipes, kern.ipc.pipefragretry, kern.ipc.pipeallocfail, 78 * and kern.ipc.piperesizefail. 79 * 80 * Locking rules: There are two locks present here: A mutex, used via 81 * PIPE_LOCK, and a flag, used via pipelock(). All locking is done via 82 * the flag, as mutexes can not persist over uiomove. The mutex 83 * exists only to guard access to the flag, and is not in itself a 84 * locking mechanism. Also note that there is only a single mutex for 85 * both directions of a pipe. 86 * 87 * As pipelock() may have to sleep before it can acquire the flag, it 88 * is important to reread all data after a call to pipelock(); everything 89 * in the structure may have changed. 90 */ 91 92 #include <sys/cdefs.h> 93 __FBSDID("$FreeBSD$"); 94 95 #include <sys/param.h> 96 #include <sys/systm.h> 97 #include <sys/conf.h> 98 #include <sys/fcntl.h> 99 #include <sys/file.h> 100 #include <sys/filedesc.h> 101 #include <sys/filio.h> 102 #include <sys/kernel.h> 103 #include <sys/lock.h> 104 #include <sys/mutex.h> 105 #include <sys/ttycom.h> 106 #include <sys/stat.h> 107 #include <sys/malloc.h> 108 #include <sys/poll.h> 109 #include <sys/selinfo.h> 110 #include <sys/signalvar.h> 111 #include <sys/syscallsubr.h> 112 #include <sys/sysctl.h> 113 #include <sys/sysproto.h> 114 #include <sys/pipe.h> 115 #include <sys/proc.h> 116 #include <sys/vnode.h> 117 #include <sys/uio.h> 118 #include <sys/event.h> 119 120 #include <security/mac/mac_framework.h> 121 122 #include <vm/vm.h> 123 #include <vm/vm_param.h> 124 #include <vm/vm_object.h> 125 #include <vm/vm_kern.h> 126 #include <vm/vm_extern.h> 127 #include <vm/pmap.h> 128 #include <vm/vm_map.h> 129 #include <vm/vm_page.h> 130 #include <vm/uma.h> 131 132 /* 133 * Use this define if you want to disable *fancy* VM things. Expect an 134 * approx 30% decrease in transfer rate. This could be useful for 135 * NetBSD or OpenBSD. 136 */ 137 /* #define PIPE_NODIRECT */ 138 139 #define PIPE_PEER(pipe) \ 140 (((pipe)->pipe_state & PIPE_NAMED) ? (pipe) : ((pipe)->pipe_peer)) 141 142 /* 143 * interfaces to the outside world 144 */ 145 static fo_rdwr_t pipe_read; 146 static fo_rdwr_t pipe_write; 147 static fo_truncate_t pipe_truncate; 148 static fo_ioctl_t pipe_ioctl; 149 static fo_poll_t pipe_poll; 150 static fo_kqfilter_t pipe_kqfilter; 151 static fo_stat_t pipe_stat; 152 static fo_close_t pipe_close; 153 static fo_chmod_t pipe_chmod; 154 static fo_chown_t pipe_chown; 155 156 struct fileops pipeops = { 157 .fo_read = pipe_read, 158 .fo_write = pipe_write, 159 .fo_truncate = pipe_truncate, 160 .fo_ioctl = pipe_ioctl, 161 .fo_poll = pipe_poll, 162 .fo_kqfilter = pipe_kqfilter, 163 .fo_stat = pipe_stat, 164 .fo_close = pipe_close, 165 .fo_chmod = pipe_chmod, 166 .fo_chown = pipe_chown, 167 .fo_flags = DFLAG_PASSABLE 168 }; 169 170 static void filt_pipedetach(struct knote *kn); 171 static void filt_pipedetach_notsup(struct knote *kn); 172 static int filt_pipenotsup(struct knote *kn, long hint); 173 static int filt_piperead(struct knote *kn, long hint); 174 static int filt_pipewrite(struct knote *kn, long hint); 175 176 static struct filterops pipe_nfiltops = { 177 .f_isfd = 1, 178 .f_detach = filt_pipedetach_notsup, 179 .f_event = filt_pipenotsup 180 }; 181 static struct filterops pipe_rfiltops = { 182 .f_isfd = 1, 183 .f_detach = filt_pipedetach, 184 .f_event = filt_piperead 185 }; 186 static struct filterops pipe_wfiltops = { 187 .f_isfd = 1, 188 .f_detach = filt_pipedetach, 189 .f_event = filt_pipewrite 190 }; 191 192 /* 193 * Default pipe buffer size(s), this can be kind-of large now because pipe 194 * space is pageable. The pipe code will try to maintain locality of 195 * reference for performance reasons, so small amounts of outstanding I/O 196 * will not wipe the cache. 197 */ 198 #define MINPIPESIZE (PIPE_SIZE/3) 199 #define MAXPIPESIZE (2*PIPE_SIZE/3) 200 201 static long amountpipekva; 202 static int pipefragretry; 203 static int pipeallocfail; 204 static int piperesizefail; 205 static int piperesizeallowed = 1; 206 207 SYSCTL_LONG(_kern_ipc, OID_AUTO, maxpipekva, CTLFLAG_RDTUN, 208 &maxpipekva, 0, "Pipe KVA limit"); 209 SYSCTL_LONG(_kern_ipc, OID_AUTO, pipekva, CTLFLAG_RD, 210 &amountpipekva, 0, "Pipe KVA usage"); 211 SYSCTL_INT(_kern_ipc, OID_AUTO, pipefragretry, CTLFLAG_RD, 212 &pipefragretry, 0, "Pipe allocation retries due to fragmentation"); 213 SYSCTL_INT(_kern_ipc, OID_AUTO, pipeallocfail, CTLFLAG_RD, 214 &pipeallocfail, 0, "Pipe allocation failures"); 215 SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizefail, CTLFLAG_RD, 216 &piperesizefail, 0, "Pipe resize failures"); 217 SYSCTL_INT(_kern_ipc, OID_AUTO, piperesizeallowed, CTLFLAG_RW, 218 &piperesizeallowed, 0, "Pipe resizing allowed"); 219 220 static void pipeinit(void *dummy __unused); 221 static void pipeclose(struct pipe *cpipe); 222 static void pipe_free_kmem(struct pipe *cpipe); 223 static int pipe_create(struct pipe *pipe, int backing); 224 static int pipe_paircreate(struct thread *td, struct pipepair **p_pp); 225 static __inline int pipelock(struct pipe *cpipe, int catch); 226 static __inline void pipeunlock(struct pipe *cpipe); 227 #ifndef PIPE_NODIRECT 228 static int pipe_build_write_buffer(struct pipe *wpipe, struct uio *uio); 229 static void pipe_destroy_write_buffer(struct pipe *wpipe); 230 static int pipe_direct_write(struct pipe *wpipe, struct uio *uio); 231 static void pipe_clone_write_buffer(struct pipe *wpipe); 232 #endif 233 static int pipespace(struct pipe *cpipe, int size); 234 static int pipespace_new(struct pipe *cpipe, int size); 235 236 static int pipe_zone_ctor(void *mem, int size, void *arg, int flags); 237 static int pipe_zone_init(void *mem, int size, int flags); 238 static void pipe_zone_fini(void *mem, int size); 239 240 static uma_zone_t pipe_zone; 241 static struct unrhdr *pipeino_unr; 242 static dev_t pipedev_ino; 243 244 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_ANY, pipeinit, NULL); 245 246 static void 247 pipeinit(void *dummy __unused) 248 { 249 250 pipe_zone = uma_zcreate("pipe", sizeof(struct pipepair), 251 pipe_zone_ctor, NULL, pipe_zone_init, pipe_zone_fini, 252 UMA_ALIGN_PTR, 0); 253 KASSERT(pipe_zone != NULL, ("pipe_zone not initialized")); 254 pipeino_unr = new_unrhdr(1, INT32_MAX, NULL); 255 KASSERT(pipeino_unr != NULL, ("pipe fake inodes not initialized")); 256 pipedev_ino = devfs_alloc_cdp_inode(); 257 KASSERT(pipedev_ino > 0, ("pipe dev inode not initialized")); 258 } 259 260 static int 261 pipe_zone_ctor(void *mem, int size, void *arg, int flags) 262 { 263 struct pipepair *pp; 264 struct pipe *rpipe, *wpipe; 265 266 KASSERT(size == sizeof(*pp), ("pipe_zone_ctor: wrong size")); 267 268 pp = (struct pipepair *)mem; 269 270 /* 271 * We zero both pipe endpoints to make sure all the kmem pointers 272 * are NULL, flag fields are zero'd, etc. We timestamp both 273 * endpoints with the same time. 274 */ 275 rpipe = &pp->pp_rpipe; 276 bzero(rpipe, sizeof(*rpipe)); 277 vfs_timestamp(&rpipe->pipe_ctime); 278 rpipe->pipe_atime = rpipe->pipe_mtime = rpipe->pipe_ctime; 279 280 wpipe = &pp->pp_wpipe; 281 bzero(wpipe, sizeof(*wpipe)); 282 wpipe->pipe_ctime = rpipe->pipe_ctime; 283 wpipe->pipe_atime = wpipe->pipe_mtime = rpipe->pipe_ctime; 284 285 rpipe->pipe_peer = wpipe; 286 rpipe->pipe_pair = pp; 287 wpipe->pipe_peer = rpipe; 288 wpipe->pipe_pair = pp; 289 290 /* 291 * Mark both endpoints as present; they will later get free'd 292 * one at a time. When both are free'd, then the whole pair 293 * is released. 294 */ 295 rpipe->pipe_present = PIPE_ACTIVE; 296 wpipe->pipe_present = PIPE_ACTIVE; 297 298 /* 299 * Eventually, the MAC Framework may initialize the label 300 * in ctor or init, but for now we do it elswhere to avoid 301 * blocking in ctor or init. 302 */ 303 pp->pp_label = NULL; 304 305 return (0); 306 } 307 308 static int 309 pipe_zone_init(void *mem, int size, int flags) 310 { 311 struct pipepair *pp; 312 313 KASSERT(size == sizeof(*pp), ("pipe_zone_init: wrong size")); 314 315 pp = (struct pipepair *)mem; 316 317 mtx_init(&pp->pp_mtx, "pipe mutex", NULL, MTX_DEF | MTX_RECURSE); 318 return (0); 319 } 320 321 static void 322 pipe_zone_fini(void *mem, int size) 323 { 324 struct pipepair *pp; 325 326 KASSERT(size == sizeof(*pp), ("pipe_zone_fini: wrong size")); 327 328 pp = (struct pipepair *)mem; 329 330 mtx_destroy(&pp->pp_mtx); 331 } 332 333 static int 334 pipe_paircreate(struct thread *td, struct pipepair **p_pp) 335 { 336 struct pipepair *pp; 337 struct pipe *rpipe, *wpipe; 338 int error; 339 340 *p_pp = pp = uma_zalloc(pipe_zone, M_WAITOK); 341 #ifdef MAC 342 /* 343 * The MAC label is shared between the connected endpoints. As a 344 * result mac_pipe_init() and mac_pipe_create() are called once 345 * for the pair, and not on the endpoints. 346 */ 347 mac_pipe_init(pp); 348 mac_pipe_create(td->td_ucred, pp); 349 #endif 350 rpipe = &pp->pp_rpipe; 351 wpipe = &pp->pp_wpipe; 352 353 knlist_init_mtx(&rpipe->pipe_sel.si_note, PIPE_MTX(rpipe)); 354 knlist_init_mtx(&wpipe->pipe_sel.si_note, PIPE_MTX(wpipe)); 355 356 /* Only the forward direction pipe is backed by default */ 357 if ((error = pipe_create(rpipe, 1)) != 0 || 358 (error = pipe_create(wpipe, 0)) != 0) { 359 pipeclose(rpipe); 360 pipeclose(wpipe); 361 return (error); 362 } 363 364 rpipe->pipe_state |= PIPE_DIRECTOK; 365 wpipe->pipe_state |= PIPE_DIRECTOK; 366 return (0); 367 } 368 369 int 370 pipe_named_ctor(struct pipe **ppipe, struct thread *td) 371 { 372 struct pipepair *pp; 373 int error; 374 375 error = pipe_paircreate(td, &pp); 376 if (error != 0) 377 return (error); 378 pp->pp_rpipe.pipe_state |= PIPE_NAMED; 379 *ppipe = &pp->pp_rpipe; 380 return (0); 381 } 382 383 void 384 pipe_dtor(struct pipe *dpipe) 385 { 386 ino_t ino; 387 388 ino = dpipe->pipe_ino; 389 funsetown(&dpipe->pipe_sigio); 390 pipeclose(dpipe); 391 if (dpipe->pipe_state & PIPE_NAMED) { 392 dpipe = dpipe->pipe_peer; 393 funsetown(&dpipe->pipe_sigio); 394 pipeclose(dpipe); 395 } 396 if (ino != 0 && ino != (ino_t)-1) 397 free_unr(pipeino_unr, ino); 398 } 399 400 /* 401 * The pipe system call for the DTYPE_PIPE type of pipes. If we fail, let 402 * the zone pick up the pieces via pipeclose(). 403 */ 404 int 405 kern_pipe(struct thread *td, int fildes[2]) 406 { 407 408 return (kern_pipe2(td, fildes, 0)); 409 } 410 411 int 412 kern_pipe2(struct thread *td, int fildes[2], int flags) 413 { 414 struct filedesc *fdp; 415 struct file *rf, *wf; 416 struct pipe *rpipe, *wpipe; 417 struct pipepair *pp; 418 int fd, fflags, error; 419 420 fdp = td->td_proc->p_fd; 421 error = pipe_paircreate(td, &pp); 422 if (error != 0) 423 return (error); 424 rpipe = &pp->pp_rpipe; 425 wpipe = &pp->pp_wpipe; 426 error = falloc(td, &rf, &fd, flags); 427 if (error) { 428 pipeclose(rpipe); 429 pipeclose(wpipe); 430 return (error); 431 } 432 /* An extra reference on `rf' has been held for us by falloc(). */ 433 fildes[0] = fd; 434 435 fflags = FREAD | FWRITE; 436 if ((flags & O_NONBLOCK) != 0) 437 fflags |= FNONBLOCK; 438 439 /* 440 * Warning: once we've gotten past allocation of the fd for the 441 * read-side, we can only drop the read side via fdrop() in order 442 * to avoid races against processes which manage to dup() the read 443 * side while we are blocked trying to allocate the write side. 444 */ 445 finit(rf, fflags, DTYPE_PIPE, rpipe, &pipeops); 446 error = falloc(td, &wf, &fd, flags); 447 if (error) { 448 fdclose(fdp, rf, fildes[0], td); 449 fdrop(rf, td); 450 /* rpipe has been closed by fdrop(). */ 451 pipeclose(wpipe); 452 return (error); 453 } 454 /* An extra reference on `wf' has been held for us by falloc(). */ 455 finit(wf, fflags, DTYPE_PIPE, wpipe, &pipeops); 456 fdrop(wf, td); 457 fildes[1] = fd; 458 fdrop(rf, td); 459 460 return (0); 461 } 462 463 /* ARGSUSED */ 464 int 465 sys_pipe(struct thread *td, struct pipe_args *uap) 466 { 467 int error; 468 int fildes[2]; 469 470 error = kern_pipe(td, fildes); 471 if (error) 472 return (error); 473 474 td->td_retval[0] = fildes[0]; 475 td->td_retval[1] = fildes[1]; 476 477 return (0); 478 } 479 480 /* 481 * Allocate kva for pipe circular buffer, the space is pageable 482 * This routine will 'realloc' the size of a pipe safely, if it fails 483 * it will retain the old buffer. 484 * If it fails it will return ENOMEM. 485 */ 486 static int 487 pipespace_new(cpipe, size) 488 struct pipe *cpipe; 489 int size; 490 { 491 caddr_t buffer; 492 int error, cnt, firstseg; 493 static int curfail = 0; 494 static struct timeval lastfail; 495 496 KASSERT(!mtx_owned(PIPE_MTX(cpipe)), ("pipespace: pipe mutex locked")); 497 KASSERT(!(cpipe->pipe_state & PIPE_DIRECTW), 498 ("pipespace: resize of direct writes not allowed")); 499 retry: 500 cnt = cpipe->pipe_buffer.cnt; 501 if (cnt > size) 502 size = cnt; 503 504 size = round_page(size); 505 buffer = (caddr_t) vm_map_min(pipe_map); 506 507 error = vm_map_find(pipe_map, NULL, 0, 508 (vm_offset_t *) &buffer, size, 1, 509 VM_PROT_ALL, VM_PROT_ALL, 0); 510 if (error != KERN_SUCCESS) { 511 if ((cpipe->pipe_buffer.buffer == NULL) && 512 (size > SMALL_PIPE_SIZE)) { 513 size = SMALL_PIPE_SIZE; 514 pipefragretry++; 515 goto retry; 516 } 517 if (cpipe->pipe_buffer.buffer == NULL) { 518 pipeallocfail++; 519 if (ppsratecheck(&lastfail, &curfail, 1)) 520 printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n"); 521 } else { 522 piperesizefail++; 523 } 524 return (ENOMEM); 525 } 526 527 /* copy data, then free old resources if we're resizing */ 528 if (cnt > 0) { 529 if (cpipe->pipe_buffer.in <= cpipe->pipe_buffer.out) { 530 firstseg = cpipe->pipe_buffer.size - cpipe->pipe_buffer.out; 531 bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out], 532 buffer, firstseg); 533 if ((cnt - firstseg) > 0) 534 bcopy(cpipe->pipe_buffer.buffer, &buffer[firstseg], 535 cpipe->pipe_buffer.in); 536 } else { 537 bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out], 538 buffer, cnt); 539 } 540 } 541 pipe_free_kmem(cpipe); 542 cpipe->pipe_buffer.buffer = buffer; 543 cpipe->pipe_buffer.size = size; 544 cpipe->pipe_buffer.in = cnt; 545 cpipe->pipe_buffer.out = 0; 546 cpipe->pipe_buffer.cnt = cnt; 547 atomic_add_long(&amountpipekva, cpipe->pipe_buffer.size); 548 return (0); 549 } 550 551 /* 552 * Wrapper for pipespace_new() that performs locking assertions. 553 */ 554 static int 555 pipespace(cpipe, size) 556 struct pipe *cpipe; 557 int size; 558 { 559 560 KASSERT(cpipe->pipe_state & PIPE_LOCKFL, 561 ("Unlocked pipe passed to pipespace")); 562 return (pipespace_new(cpipe, size)); 563 } 564 565 /* 566 * lock a pipe for I/O, blocking other access 567 */ 568 static __inline int 569 pipelock(cpipe, catch) 570 struct pipe *cpipe; 571 int catch; 572 { 573 int error; 574 575 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 576 while (cpipe->pipe_state & PIPE_LOCKFL) { 577 cpipe->pipe_state |= PIPE_LWANT; 578 error = msleep(cpipe, PIPE_MTX(cpipe), 579 catch ? (PRIBIO | PCATCH) : PRIBIO, 580 "pipelk", 0); 581 if (error != 0) 582 return (error); 583 } 584 cpipe->pipe_state |= PIPE_LOCKFL; 585 return (0); 586 } 587 588 /* 589 * unlock a pipe I/O lock 590 */ 591 static __inline void 592 pipeunlock(cpipe) 593 struct pipe *cpipe; 594 { 595 596 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 597 KASSERT(cpipe->pipe_state & PIPE_LOCKFL, 598 ("Unlocked pipe passed to pipeunlock")); 599 cpipe->pipe_state &= ~PIPE_LOCKFL; 600 if (cpipe->pipe_state & PIPE_LWANT) { 601 cpipe->pipe_state &= ~PIPE_LWANT; 602 wakeup(cpipe); 603 } 604 } 605 606 void 607 pipeselwakeup(cpipe) 608 struct pipe *cpipe; 609 { 610 611 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 612 if (cpipe->pipe_state & PIPE_SEL) { 613 selwakeuppri(&cpipe->pipe_sel, PSOCK); 614 if (!SEL_WAITING(&cpipe->pipe_sel)) 615 cpipe->pipe_state &= ~PIPE_SEL; 616 } 617 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) 618 pgsigio(&cpipe->pipe_sigio, SIGIO, 0); 619 KNOTE_LOCKED(&cpipe->pipe_sel.si_note, 0); 620 } 621 622 /* 623 * Initialize and allocate VM and memory for pipe. The structure 624 * will start out zero'd from the ctor, so we just manage the kmem. 625 */ 626 static int 627 pipe_create(pipe, backing) 628 struct pipe *pipe; 629 int backing; 630 { 631 int error; 632 633 if (backing) { 634 if (amountpipekva > maxpipekva / 2) 635 error = pipespace_new(pipe, SMALL_PIPE_SIZE); 636 else 637 error = pipespace_new(pipe, PIPE_SIZE); 638 } else { 639 /* If we're not backing this pipe, no need to do anything. */ 640 error = 0; 641 } 642 pipe->pipe_ino = -1; 643 return (error); 644 } 645 646 /* ARGSUSED */ 647 static int 648 pipe_read(fp, uio, active_cred, flags, td) 649 struct file *fp; 650 struct uio *uio; 651 struct ucred *active_cred; 652 struct thread *td; 653 int flags; 654 { 655 struct pipe *rpipe; 656 int error; 657 int nread = 0; 658 int size; 659 660 rpipe = fp->f_data; 661 PIPE_LOCK(rpipe); 662 ++rpipe->pipe_busy; 663 error = pipelock(rpipe, 1); 664 if (error) 665 goto unlocked_error; 666 667 #ifdef MAC 668 error = mac_pipe_check_read(active_cred, rpipe->pipe_pair); 669 if (error) 670 goto locked_error; 671 #endif 672 if (amountpipekva > (3 * maxpipekva) / 4) { 673 if (!(rpipe->pipe_state & PIPE_DIRECTW) && 674 (rpipe->pipe_buffer.size > SMALL_PIPE_SIZE) && 675 (rpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) && 676 (piperesizeallowed == 1)) { 677 PIPE_UNLOCK(rpipe); 678 pipespace(rpipe, SMALL_PIPE_SIZE); 679 PIPE_LOCK(rpipe); 680 } 681 } 682 683 while (uio->uio_resid) { 684 /* 685 * normal pipe buffer receive 686 */ 687 if (rpipe->pipe_buffer.cnt > 0) { 688 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 689 if (size > rpipe->pipe_buffer.cnt) 690 size = rpipe->pipe_buffer.cnt; 691 if (size > uio->uio_resid) 692 size = uio->uio_resid; 693 694 PIPE_UNLOCK(rpipe); 695 error = uiomove( 696 &rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 697 size, uio); 698 PIPE_LOCK(rpipe); 699 if (error) 700 break; 701 702 rpipe->pipe_buffer.out += size; 703 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 704 rpipe->pipe_buffer.out = 0; 705 706 rpipe->pipe_buffer.cnt -= size; 707 708 /* 709 * If there is no more to read in the pipe, reset 710 * its pointers to the beginning. This improves 711 * cache hit stats. 712 */ 713 if (rpipe->pipe_buffer.cnt == 0) { 714 rpipe->pipe_buffer.in = 0; 715 rpipe->pipe_buffer.out = 0; 716 } 717 nread += size; 718 #ifndef PIPE_NODIRECT 719 /* 720 * Direct copy, bypassing a kernel buffer. 721 */ 722 } else if ((size = rpipe->pipe_map.cnt) && 723 (rpipe->pipe_state & PIPE_DIRECTW)) { 724 if (size > uio->uio_resid) 725 size = (u_int) uio->uio_resid; 726 727 PIPE_UNLOCK(rpipe); 728 error = uiomove_fromphys(rpipe->pipe_map.ms, 729 rpipe->pipe_map.pos, size, uio); 730 PIPE_LOCK(rpipe); 731 if (error) 732 break; 733 nread += size; 734 rpipe->pipe_map.pos += size; 735 rpipe->pipe_map.cnt -= size; 736 if (rpipe->pipe_map.cnt == 0) { 737 rpipe->pipe_state &= ~(PIPE_DIRECTW|PIPE_WANTW); 738 wakeup(rpipe); 739 } 740 #endif 741 } else { 742 /* 743 * detect EOF condition 744 * read returns 0 on EOF, no need to set error 745 */ 746 if (rpipe->pipe_state & PIPE_EOF) 747 break; 748 749 /* 750 * If the "write-side" has been blocked, wake it up now. 751 */ 752 if (rpipe->pipe_state & PIPE_WANTW) { 753 rpipe->pipe_state &= ~PIPE_WANTW; 754 wakeup(rpipe); 755 } 756 757 /* 758 * Break if some data was read. 759 */ 760 if (nread > 0) 761 break; 762 763 /* 764 * Unlock the pipe buffer for our remaining processing. 765 * We will either break out with an error or we will 766 * sleep and relock to loop. 767 */ 768 pipeunlock(rpipe); 769 770 /* 771 * Handle non-blocking mode operation or 772 * wait for more data. 773 */ 774 if (fp->f_flag & FNONBLOCK) { 775 error = EAGAIN; 776 } else { 777 rpipe->pipe_state |= PIPE_WANTR; 778 if ((error = msleep(rpipe, PIPE_MTX(rpipe), 779 PRIBIO | PCATCH, 780 "piperd", 0)) == 0) 781 error = pipelock(rpipe, 1); 782 } 783 if (error) 784 goto unlocked_error; 785 } 786 } 787 #ifdef MAC 788 locked_error: 789 #endif 790 pipeunlock(rpipe); 791 792 /* XXX: should probably do this before getting any locks. */ 793 if (error == 0) 794 vfs_timestamp(&rpipe->pipe_atime); 795 unlocked_error: 796 --rpipe->pipe_busy; 797 798 /* 799 * PIPE_WANT processing only makes sense if pipe_busy is 0. 800 */ 801 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 802 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 803 wakeup(rpipe); 804 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 805 /* 806 * Handle write blocking hysteresis. 807 */ 808 if (rpipe->pipe_state & PIPE_WANTW) { 809 rpipe->pipe_state &= ~PIPE_WANTW; 810 wakeup(rpipe); 811 } 812 } 813 814 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 815 pipeselwakeup(rpipe); 816 817 PIPE_UNLOCK(rpipe); 818 return (error); 819 } 820 821 #ifndef PIPE_NODIRECT 822 /* 823 * Map the sending processes' buffer into kernel space and wire it. 824 * This is similar to a physical write operation. 825 */ 826 static int 827 pipe_build_write_buffer(wpipe, uio) 828 struct pipe *wpipe; 829 struct uio *uio; 830 { 831 u_int size; 832 int i; 833 834 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 835 KASSERT(wpipe->pipe_state & PIPE_DIRECTW, 836 ("Clone attempt on non-direct write pipe!")); 837 838 if (uio->uio_iov->iov_len > wpipe->pipe_buffer.size) 839 size = wpipe->pipe_buffer.size; 840 else 841 size = uio->uio_iov->iov_len; 842 843 if ((i = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 844 (vm_offset_t)uio->uio_iov->iov_base, size, VM_PROT_READ, 845 wpipe->pipe_map.ms, PIPENPAGES)) < 0) 846 return (EFAULT); 847 848 /* 849 * set up the control block 850 */ 851 wpipe->pipe_map.npages = i; 852 wpipe->pipe_map.pos = 853 ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; 854 wpipe->pipe_map.cnt = size; 855 856 /* 857 * and update the uio data 858 */ 859 860 uio->uio_iov->iov_len -= size; 861 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; 862 if (uio->uio_iov->iov_len == 0) 863 uio->uio_iov++; 864 uio->uio_resid -= size; 865 uio->uio_offset += size; 866 return (0); 867 } 868 869 /* 870 * unmap and unwire the process buffer 871 */ 872 static void 873 pipe_destroy_write_buffer(wpipe) 874 struct pipe *wpipe; 875 { 876 877 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 878 vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages); 879 wpipe->pipe_map.npages = 0; 880 } 881 882 /* 883 * In the case of a signal, the writing process might go away. This 884 * code copies the data into the circular buffer so that the source 885 * pages can be freed without loss of data. 886 */ 887 static void 888 pipe_clone_write_buffer(wpipe) 889 struct pipe *wpipe; 890 { 891 struct uio uio; 892 struct iovec iov; 893 int size; 894 int pos; 895 896 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 897 size = wpipe->pipe_map.cnt; 898 pos = wpipe->pipe_map.pos; 899 900 wpipe->pipe_buffer.in = size; 901 wpipe->pipe_buffer.out = 0; 902 wpipe->pipe_buffer.cnt = size; 903 wpipe->pipe_state &= ~PIPE_DIRECTW; 904 905 PIPE_UNLOCK(wpipe); 906 iov.iov_base = wpipe->pipe_buffer.buffer; 907 iov.iov_len = size; 908 uio.uio_iov = &iov; 909 uio.uio_iovcnt = 1; 910 uio.uio_offset = 0; 911 uio.uio_resid = size; 912 uio.uio_segflg = UIO_SYSSPACE; 913 uio.uio_rw = UIO_READ; 914 uio.uio_td = curthread; 915 uiomove_fromphys(wpipe->pipe_map.ms, pos, size, &uio); 916 PIPE_LOCK(wpipe); 917 pipe_destroy_write_buffer(wpipe); 918 } 919 920 /* 921 * This implements the pipe buffer write mechanism. Note that only 922 * a direct write OR a normal pipe write can be pending at any given time. 923 * If there are any characters in the pipe buffer, the direct write will 924 * be deferred until the receiving process grabs all of the bytes from 925 * the pipe buffer. Then the direct mapping write is set-up. 926 */ 927 static int 928 pipe_direct_write(wpipe, uio) 929 struct pipe *wpipe; 930 struct uio *uio; 931 { 932 int error; 933 934 retry: 935 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 936 error = pipelock(wpipe, 1); 937 if (wpipe->pipe_state & PIPE_EOF) 938 error = EPIPE; 939 if (error) { 940 pipeunlock(wpipe); 941 goto error1; 942 } 943 while (wpipe->pipe_state & PIPE_DIRECTW) { 944 if (wpipe->pipe_state & PIPE_WANTR) { 945 wpipe->pipe_state &= ~PIPE_WANTR; 946 wakeup(wpipe); 947 } 948 pipeselwakeup(wpipe); 949 wpipe->pipe_state |= PIPE_WANTW; 950 pipeunlock(wpipe); 951 error = msleep(wpipe, PIPE_MTX(wpipe), 952 PRIBIO | PCATCH, "pipdww", 0); 953 if (error) 954 goto error1; 955 else 956 goto retry; 957 } 958 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 959 if (wpipe->pipe_buffer.cnt > 0) { 960 if (wpipe->pipe_state & PIPE_WANTR) { 961 wpipe->pipe_state &= ~PIPE_WANTR; 962 wakeup(wpipe); 963 } 964 pipeselwakeup(wpipe); 965 wpipe->pipe_state |= PIPE_WANTW; 966 pipeunlock(wpipe); 967 error = msleep(wpipe, PIPE_MTX(wpipe), 968 PRIBIO | PCATCH, "pipdwc", 0); 969 if (error) 970 goto error1; 971 else 972 goto retry; 973 } 974 975 wpipe->pipe_state |= PIPE_DIRECTW; 976 977 PIPE_UNLOCK(wpipe); 978 error = pipe_build_write_buffer(wpipe, uio); 979 PIPE_LOCK(wpipe); 980 if (error) { 981 wpipe->pipe_state &= ~PIPE_DIRECTW; 982 pipeunlock(wpipe); 983 goto error1; 984 } 985 986 error = 0; 987 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 988 if (wpipe->pipe_state & PIPE_EOF) { 989 pipe_destroy_write_buffer(wpipe); 990 pipeselwakeup(wpipe); 991 pipeunlock(wpipe); 992 error = EPIPE; 993 goto error1; 994 } 995 if (wpipe->pipe_state & PIPE_WANTR) { 996 wpipe->pipe_state &= ~PIPE_WANTR; 997 wakeup(wpipe); 998 } 999 pipeselwakeup(wpipe); 1000 wpipe->pipe_state |= PIPE_WANTW; 1001 pipeunlock(wpipe); 1002 error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, 1003 "pipdwt", 0); 1004 pipelock(wpipe, 0); 1005 } 1006 1007 if (wpipe->pipe_state & PIPE_EOF) 1008 error = EPIPE; 1009 if (wpipe->pipe_state & PIPE_DIRECTW) { 1010 /* 1011 * this bit of trickery substitutes a kernel buffer for 1012 * the process that might be going away. 1013 */ 1014 pipe_clone_write_buffer(wpipe); 1015 } else { 1016 pipe_destroy_write_buffer(wpipe); 1017 } 1018 pipeunlock(wpipe); 1019 return (error); 1020 1021 error1: 1022 wakeup(wpipe); 1023 return (error); 1024 } 1025 #endif 1026 1027 static int 1028 pipe_write(fp, uio, active_cred, flags, td) 1029 struct file *fp; 1030 struct uio *uio; 1031 struct ucred *active_cred; 1032 struct thread *td; 1033 int flags; 1034 { 1035 int error = 0; 1036 int desiredsize; 1037 ssize_t orig_resid; 1038 struct pipe *wpipe, *rpipe; 1039 1040 rpipe = fp->f_data; 1041 wpipe = PIPE_PEER(rpipe); 1042 PIPE_LOCK(rpipe); 1043 error = pipelock(wpipe, 1); 1044 if (error) { 1045 PIPE_UNLOCK(rpipe); 1046 return (error); 1047 } 1048 /* 1049 * detect loss of pipe read side, issue SIGPIPE if lost. 1050 */ 1051 if (wpipe->pipe_present != PIPE_ACTIVE || 1052 (wpipe->pipe_state & PIPE_EOF)) { 1053 pipeunlock(wpipe); 1054 PIPE_UNLOCK(rpipe); 1055 return (EPIPE); 1056 } 1057 #ifdef MAC 1058 error = mac_pipe_check_write(active_cred, wpipe->pipe_pair); 1059 if (error) { 1060 pipeunlock(wpipe); 1061 PIPE_UNLOCK(rpipe); 1062 return (error); 1063 } 1064 #endif 1065 ++wpipe->pipe_busy; 1066 1067 /* Choose a larger size if it's advantageous */ 1068 desiredsize = max(SMALL_PIPE_SIZE, wpipe->pipe_buffer.size); 1069 while (desiredsize < wpipe->pipe_buffer.cnt + uio->uio_resid) { 1070 if (piperesizeallowed != 1) 1071 break; 1072 if (amountpipekva > maxpipekva / 2) 1073 break; 1074 if (desiredsize == BIG_PIPE_SIZE) 1075 break; 1076 desiredsize = desiredsize * 2; 1077 } 1078 1079 /* Choose a smaller size if we're in a OOM situation */ 1080 if ((amountpipekva > (3 * maxpipekva) / 4) && 1081 (wpipe->pipe_buffer.size > SMALL_PIPE_SIZE) && 1082 (wpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) && 1083 (piperesizeallowed == 1)) 1084 desiredsize = SMALL_PIPE_SIZE; 1085 1086 /* Resize if the above determined that a new size was necessary */ 1087 if ((desiredsize != wpipe->pipe_buffer.size) && 1088 ((wpipe->pipe_state & PIPE_DIRECTW) == 0)) { 1089 PIPE_UNLOCK(wpipe); 1090 pipespace(wpipe, desiredsize); 1091 PIPE_LOCK(wpipe); 1092 } 1093 if (wpipe->pipe_buffer.size == 0) { 1094 /* 1095 * This can only happen for reverse direction use of pipes 1096 * in a complete OOM situation. 1097 */ 1098 error = ENOMEM; 1099 --wpipe->pipe_busy; 1100 pipeunlock(wpipe); 1101 PIPE_UNLOCK(wpipe); 1102 return (error); 1103 } 1104 1105 pipeunlock(wpipe); 1106 1107 orig_resid = uio->uio_resid; 1108 1109 while (uio->uio_resid) { 1110 int space; 1111 1112 pipelock(wpipe, 0); 1113 if (wpipe->pipe_state & PIPE_EOF) { 1114 pipeunlock(wpipe); 1115 error = EPIPE; 1116 break; 1117 } 1118 #ifndef PIPE_NODIRECT 1119 /* 1120 * If the transfer is large, we can gain performance if 1121 * we do process-to-process copies directly. 1122 * If the write is non-blocking, we don't use the 1123 * direct write mechanism. 1124 * 1125 * The direct write mechanism will detect the reader going 1126 * away on us. 1127 */ 1128 if (uio->uio_segflg == UIO_USERSPACE && 1129 uio->uio_iov->iov_len >= PIPE_MINDIRECT && 1130 wpipe->pipe_buffer.size >= PIPE_MINDIRECT && 1131 (fp->f_flag & FNONBLOCK) == 0) { 1132 pipeunlock(wpipe); 1133 error = pipe_direct_write(wpipe, uio); 1134 if (error) 1135 break; 1136 continue; 1137 } 1138 #endif 1139 1140 /* 1141 * Pipe buffered writes cannot be coincidental with 1142 * direct writes. We wait until the currently executing 1143 * direct write is completed before we start filling the 1144 * pipe buffer. We break out if a signal occurs or the 1145 * reader goes away. 1146 */ 1147 if (wpipe->pipe_state & PIPE_DIRECTW) { 1148 if (wpipe->pipe_state & PIPE_WANTR) { 1149 wpipe->pipe_state &= ~PIPE_WANTR; 1150 wakeup(wpipe); 1151 } 1152 pipeselwakeup(wpipe); 1153 wpipe->pipe_state |= PIPE_WANTW; 1154 pipeunlock(wpipe); 1155 error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH, 1156 "pipbww", 0); 1157 if (error) 1158 break; 1159 else 1160 continue; 1161 } 1162 1163 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1164 1165 /* Writes of size <= PIPE_BUF must be atomic. */ 1166 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 1167 space = 0; 1168 1169 if (space > 0) { 1170 int size; /* Transfer size */ 1171 int segsize; /* first segment to transfer */ 1172 1173 /* 1174 * Transfer size is minimum of uio transfer 1175 * and free space in pipe buffer. 1176 */ 1177 if (space > uio->uio_resid) 1178 size = uio->uio_resid; 1179 else 1180 size = space; 1181 /* 1182 * First segment to transfer is minimum of 1183 * transfer size and contiguous space in 1184 * pipe buffer. If first segment to transfer 1185 * is less than the transfer size, we've got 1186 * a wraparound in the buffer. 1187 */ 1188 segsize = wpipe->pipe_buffer.size - 1189 wpipe->pipe_buffer.in; 1190 if (segsize > size) 1191 segsize = size; 1192 1193 /* Transfer first segment */ 1194 1195 PIPE_UNLOCK(rpipe); 1196 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1197 segsize, uio); 1198 PIPE_LOCK(rpipe); 1199 1200 if (error == 0 && segsize < size) { 1201 KASSERT(wpipe->pipe_buffer.in + segsize == 1202 wpipe->pipe_buffer.size, 1203 ("Pipe buffer wraparound disappeared")); 1204 /* 1205 * Transfer remaining part now, to 1206 * support atomic writes. Wraparound 1207 * happened. 1208 */ 1209 1210 PIPE_UNLOCK(rpipe); 1211 error = uiomove( 1212 &wpipe->pipe_buffer.buffer[0], 1213 size - segsize, uio); 1214 PIPE_LOCK(rpipe); 1215 } 1216 if (error == 0) { 1217 wpipe->pipe_buffer.in += size; 1218 if (wpipe->pipe_buffer.in >= 1219 wpipe->pipe_buffer.size) { 1220 KASSERT(wpipe->pipe_buffer.in == 1221 size - segsize + 1222 wpipe->pipe_buffer.size, 1223 ("Expected wraparound bad")); 1224 wpipe->pipe_buffer.in = size - segsize; 1225 } 1226 1227 wpipe->pipe_buffer.cnt += size; 1228 KASSERT(wpipe->pipe_buffer.cnt <= 1229 wpipe->pipe_buffer.size, 1230 ("Pipe buffer overflow")); 1231 } 1232 pipeunlock(wpipe); 1233 if (error != 0) 1234 break; 1235 } else { 1236 /* 1237 * If the "read-side" has been blocked, wake it up now. 1238 */ 1239 if (wpipe->pipe_state & PIPE_WANTR) { 1240 wpipe->pipe_state &= ~PIPE_WANTR; 1241 wakeup(wpipe); 1242 } 1243 1244 /* 1245 * don't block on non-blocking I/O 1246 */ 1247 if (fp->f_flag & FNONBLOCK) { 1248 error = EAGAIN; 1249 pipeunlock(wpipe); 1250 break; 1251 } 1252 1253 /* 1254 * We have no more space and have something to offer, 1255 * wake up select/poll. 1256 */ 1257 pipeselwakeup(wpipe); 1258 1259 wpipe->pipe_state |= PIPE_WANTW; 1260 pipeunlock(wpipe); 1261 error = msleep(wpipe, PIPE_MTX(rpipe), 1262 PRIBIO | PCATCH, "pipewr", 0); 1263 if (error != 0) 1264 break; 1265 } 1266 } 1267 1268 pipelock(wpipe, 0); 1269 --wpipe->pipe_busy; 1270 1271 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1272 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1273 wakeup(wpipe); 1274 } else if (wpipe->pipe_buffer.cnt > 0) { 1275 /* 1276 * If we have put any characters in the buffer, we wake up 1277 * the reader. 1278 */ 1279 if (wpipe->pipe_state & PIPE_WANTR) { 1280 wpipe->pipe_state &= ~PIPE_WANTR; 1281 wakeup(wpipe); 1282 } 1283 } 1284 1285 /* 1286 * Don't return EPIPE if I/O was successful 1287 */ 1288 if ((wpipe->pipe_buffer.cnt == 0) && 1289 (uio->uio_resid == 0) && 1290 (error == EPIPE)) { 1291 error = 0; 1292 } 1293 1294 if (error == 0) 1295 vfs_timestamp(&wpipe->pipe_mtime); 1296 1297 /* 1298 * We have something to offer, 1299 * wake up select/poll. 1300 */ 1301 if (wpipe->pipe_buffer.cnt) 1302 pipeselwakeup(wpipe); 1303 1304 pipeunlock(wpipe); 1305 PIPE_UNLOCK(rpipe); 1306 return (error); 1307 } 1308 1309 /* ARGSUSED */ 1310 static int 1311 pipe_truncate(fp, length, active_cred, td) 1312 struct file *fp; 1313 off_t length; 1314 struct ucred *active_cred; 1315 struct thread *td; 1316 { 1317 1318 /* For named pipes call the vnode operation. */ 1319 if (fp->f_vnode != NULL) 1320 return (vnops.fo_truncate(fp, length, active_cred, td)); 1321 return (EINVAL); 1322 } 1323 1324 /* 1325 * we implement a very minimal set of ioctls for compatibility with sockets. 1326 */ 1327 static int 1328 pipe_ioctl(fp, cmd, data, active_cred, td) 1329 struct file *fp; 1330 u_long cmd; 1331 void *data; 1332 struct ucred *active_cred; 1333 struct thread *td; 1334 { 1335 struct pipe *mpipe = fp->f_data; 1336 int error; 1337 1338 PIPE_LOCK(mpipe); 1339 1340 #ifdef MAC 1341 error = mac_pipe_check_ioctl(active_cred, mpipe->pipe_pair, cmd, data); 1342 if (error) { 1343 PIPE_UNLOCK(mpipe); 1344 return (error); 1345 } 1346 #endif 1347 1348 error = 0; 1349 switch (cmd) { 1350 1351 case FIONBIO: 1352 break; 1353 1354 case FIOASYNC: 1355 if (*(int *)data) { 1356 mpipe->pipe_state |= PIPE_ASYNC; 1357 } else { 1358 mpipe->pipe_state &= ~PIPE_ASYNC; 1359 } 1360 break; 1361 1362 case FIONREAD: 1363 if (!(fp->f_flag & FREAD)) { 1364 *(int *)data = 0; 1365 PIPE_UNLOCK(mpipe); 1366 return (0); 1367 } 1368 if (mpipe->pipe_state & PIPE_DIRECTW) 1369 *(int *)data = mpipe->pipe_map.cnt; 1370 else 1371 *(int *)data = mpipe->pipe_buffer.cnt; 1372 break; 1373 1374 case FIOSETOWN: 1375 PIPE_UNLOCK(mpipe); 1376 error = fsetown(*(int *)data, &mpipe->pipe_sigio); 1377 goto out_unlocked; 1378 1379 case FIOGETOWN: 1380 *(int *)data = fgetown(&mpipe->pipe_sigio); 1381 break; 1382 1383 /* This is deprecated, FIOSETOWN should be used instead. */ 1384 case TIOCSPGRP: 1385 PIPE_UNLOCK(mpipe); 1386 error = fsetown(-(*(int *)data), &mpipe->pipe_sigio); 1387 goto out_unlocked; 1388 1389 /* This is deprecated, FIOGETOWN should be used instead. */ 1390 case TIOCGPGRP: 1391 *(int *)data = -fgetown(&mpipe->pipe_sigio); 1392 break; 1393 1394 default: 1395 error = ENOTTY; 1396 break; 1397 } 1398 PIPE_UNLOCK(mpipe); 1399 out_unlocked: 1400 return (error); 1401 } 1402 1403 static int 1404 pipe_poll(fp, events, active_cred, td) 1405 struct file *fp; 1406 int events; 1407 struct ucred *active_cred; 1408 struct thread *td; 1409 { 1410 struct pipe *rpipe; 1411 struct pipe *wpipe; 1412 int levents, revents; 1413 #ifdef MAC 1414 int error; 1415 #endif 1416 1417 revents = 0; 1418 rpipe = fp->f_data; 1419 wpipe = PIPE_PEER(rpipe); 1420 PIPE_LOCK(rpipe); 1421 #ifdef MAC 1422 error = mac_pipe_check_poll(active_cred, rpipe->pipe_pair); 1423 if (error) 1424 goto locked_error; 1425 #endif 1426 if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM)) 1427 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1428 (rpipe->pipe_buffer.cnt > 0)) 1429 revents |= events & (POLLIN | POLLRDNORM); 1430 1431 if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM)) 1432 if (wpipe->pipe_present != PIPE_ACTIVE || 1433 (wpipe->pipe_state & PIPE_EOF) || 1434 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1435 ((wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF || 1436 wpipe->pipe_buffer.size == 0))) 1437 revents |= events & (POLLOUT | POLLWRNORM); 1438 1439 levents = events & 1440 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); 1441 if (rpipe->pipe_state & PIPE_NAMED && fp->f_flag & FREAD && levents && 1442 fp->f_seqcount == rpipe->pipe_wgen) 1443 events |= POLLINIGNEOF; 1444 1445 if ((events & POLLINIGNEOF) == 0) { 1446 if (rpipe->pipe_state & PIPE_EOF) { 1447 revents |= (events & (POLLIN | POLLRDNORM)); 1448 if (wpipe->pipe_present != PIPE_ACTIVE || 1449 (wpipe->pipe_state & PIPE_EOF)) 1450 revents |= POLLHUP; 1451 } 1452 } 1453 1454 if (revents == 0) { 1455 if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM)) { 1456 selrecord(td, &rpipe->pipe_sel); 1457 if (SEL_WAITING(&rpipe->pipe_sel)) 1458 rpipe->pipe_state |= PIPE_SEL; 1459 } 1460 1461 if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM)) { 1462 selrecord(td, &wpipe->pipe_sel); 1463 if (SEL_WAITING(&wpipe->pipe_sel)) 1464 wpipe->pipe_state |= PIPE_SEL; 1465 } 1466 } 1467 #ifdef MAC 1468 locked_error: 1469 #endif 1470 PIPE_UNLOCK(rpipe); 1471 1472 return (revents); 1473 } 1474 1475 /* 1476 * We shouldn't need locks here as we're doing a read and this should 1477 * be a natural race. 1478 */ 1479 static int 1480 pipe_stat(fp, ub, active_cred, td) 1481 struct file *fp; 1482 struct stat *ub; 1483 struct ucred *active_cred; 1484 struct thread *td; 1485 { 1486 struct pipe *pipe; 1487 int new_unr; 1488 #ifdef MAC 1489 int error; 1490 #endif 1491 1492 pipe = fp->f_data; 1493 PIPE_LOCK(pipe); 1494 #ifdef MAC 1495 error = mac_pipe_check_stat(active_cred, pipe->pipe_pair); 1496 if (error) { 1497 PIPE_UNLOCK(pipe); 1498 return (error); 1499 } 1500 #endif 1501 1502 /* For named pipes ask the underlying filesystem. */ 1503 if (pipe->pipe_state & PIPE_NAMED) { 1504 PIPE_UNLOCK(pipe); 1505 return (vnops.fo_stat(fp, ub, active_cred, td)); 1506 } 1507 1508 /* 1509 * Lazily allocate an inode number for the pipe. Most pipe 1510 * users do not call fstat(2) on the pipe, which means that 1511 * postponing the inode allocation until it is must be 1512 * returned to userland is useful. If alloc_unr failed, 1513 * assign st_ino zero instead of returning an error. 1514 * Special pipe_ino values: 1515 * -1 - not yet initialized; 1516 * 0 - alloc_unr failed, return 0 as st_ino forever. 1517 */ 1518 if (pipe->pipe_ino == (ino_t)-1) { 1519 new_unr = alloc_unr(pipeino_unr); 1520 if (new_unr != -1) 1521 pipe->pipe_ino = new_unr; 1522 else 1523 pipe->pipe_ino = 0; 1524 } 1525 PIPE_UNLOCK(pipe); 1526 1527 bzero(ub, sizeof(*ub)); 1528 ub->st_mode = S_IFIFO; 1529 ub->st_blksize = PAGE_SIZE; 1530 if (pipe->pipe_state & PIPE_DIRECTW) 1531 ub->st_size = pipe->pipe_map.cnt; 1532 else 1533 ub->st_size = pipe->pipe_buffer.cnt; 1534 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1535 ub->st_atim = pipe->pipe_atime; 1536 ub->st_mtim = pipe->pipe_mtime; 1537 ub->st_ctim = pipe->pipe_ctime; 1538 ub->st_uid = fp->f_cred->cr_uid; 1539 ub->st_gid = fp->f_cred->cr_gid; 1540 ub->st_dev = pipedev_ino; 1541 ub->st_ino = pipe->pipe_ino; 1542 /* 1543 * Left as 0: st_nlink, st_rdev, st_flags, st_gen. 1544 */ 1545 return (0); 1546 } 1547 1548 /* ARGSUSED */ 1549 static int 1550 pipe_close(fp, td) 1551 struct file *fp; 1552 struct thread *td; 1553 { 1554 1555 if (fp->f_vnode != NULL) 1556 return vnops.fo_close(fp, td); 1557 fp->f_ops = &badfileops; 1558 pipe_dtor(fp->f_data); 1559 fp->f_data = NULL; 1560 return (0); 1561 } 1562 1563 static int 1564 pipe_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, struct thread *td) 1565 { 1566 struct pipe *cpipe; 1567 int error; 1568 1569 cpipe = fp->f_data; 1570 if (cpipe->pipe_state & PIPE_NAMED) 1571 error = vn_chmod(fp, mode, active_cred, td); 1572 else 1573 error = invfo_chmod(fp, mode, active_cred, td); 1574 return (error); 1575 } 1576 1577 static int 1578 pipe_chown(fp, uid, gid, active_cred, td) 1579 struct file *fp; 1580 uid_t uid; 1581 gid_t gid; 1582 struct ucred *active_cred; 1583 struct thread *td; 1584 { 1585 struct pipe *cpipe; 1586 int error; 1587 1588 cpipe = fp->f_data; 1589 if (cpipe->pipe_state & PIPE_NAMED) 1590 error = vn_chown(fp, uid, gid, active_cred, td); 1591 else 1592 error = invfo_chown(fp, uid, gid, active_cred, td); 1593 return (error); 1594 } 1595 1596 static void 1597 pipe_free_kmem(cpipe) 1598 struct pipe *cpipe; 1599 { 1600 1601 KASSERT(!mtx_owned(PIPE_MTX(cpipe)), 1602 ("pipe_free_kmem: pipe mutex locked")); 1603 1604 if (cpipe->pipe_buffer.buffer != NULL) { 1605 atomic_subtract_long(&amountpipekva, cpipe->pipe_buffer.size); 1606 vm_map_remove(pipe_map, 1607 (vm_offset_t)cpipe->pipe_buffer.buffer, 1608 (vm_offset_t)cpipe->pipe_buffer.buffer + cpipe->pipe_buffer.size); 1609 cpipe->pipe_buffer.buffer = NULL; 1610 } 1611 #ifndef PIPE_NODIRECT 1612 { 1613 cpipe->pipe_map.cnt = 0; 1614 cpipe->pipe_map.pos = 0; 1615 cpipe->pipe_map.npages = 0; 1616 } 1617 #endif 1618 } 1619 1620 /* 1621 * shutdown the pipe 1622 */ 1623 static void 1624 pipeclose(cpipe) 1625 struct pipe *cpipe; 1626 { 1627 struct pipepair *pp; 1628 struct pipe *ppipe; 1629 1630 KASSERT(cpipe != NULL, ("pipeclose: cpipe == NULL")); 1631 1632 PIPE_LOCK(cpipe); 1633 pipelock(cpipe, 0); 1634 pp = cpipe->pipe_pair; 1635 1636 pipeselwakeup(cpipe); 1637 1638 /* 1639 * If the other side is blocked, wake it up saying that 1640 * we want to close it down. 1641 */ 1642 cpipe->pipe_state |= PIPE_EOF; 1643 while (cpipe->pipe_busy) { 1644 wakeup(cpipe); 1645 cpipe->pipe_state |= PIPE_WANT; 1646 pipeunlock(cpipe); 1647 msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0); 1648 pipelock(cpipe, 0); 1649 } 1650 1651 1652 /* 1653 * Disconnect from peer, if any. 1654 */ 1655 ppipe = cpipe->pipe_peer; 1656 if (ppipe->pipe_present == PIPE_ACTIVE) { 1657 pipeselwakeup(ppipe); 1658 1659 ppipe->pipe_state |= PIPE_EOF; 1660 wakeup(ppipe); 1661 KNOTE_LOCKED(&ppipe->pipe_sel.si_note, 0); 1662 } 1663 1664 /* 1665 * Mark this endpoint as free. Release kmem resources. We 1666 * don't mark this endpoint as unused until we've finished 1667 * doing that, or the pipe might disappear out from under 1668 * us. 1669 */ 1670 PIPE_UNLOCK(cpipe); 1671 pipe_free_kmem(cpipe); 1672 PIPE_LOCK(cpipe); 1673 cpipe->pipe_present = PIPE_CLOSING; 1674 pipeunlock(cpipe); 1675 1676 /* 1677 * knlist_clear() may sleep dropping the PIPE_MTX. Set the 1678 * PIPE_FINALIZED, that allows other end to free the 1679 * pipe_pair, only after the knotes are completely dismantled. 1680 */ 1681 knlist_clear(&cpipe->pipe_sel.si_note, 1); 1682 cpipe->pipe_present = PIPE_FINALIZED; 1683 seldrain(&cpipe->pipe_sel); 1684 knlist_destroy(&cpipe->pipe_sel.si_note); 1685 1686 /* 1687 * If both endpoints are now closed, release the memory for the 1688 * pipe pair. If not, unlock. 1689 */ 1690 if (ppipe->pipe_present == PIPE_FINALIZED) { 1691 PIPE_UNLOCK(cpipe); 1692 #ifdef MAC 1693 mac_pipe_destroy(pp); 1694 #endif 1695 uma_zfree(pipe_zone, cpipe->pipe_pair); 1696 } else 1697 PIPE_UNLOCK(cpipe); 1698 } 1699 1700 /*ARGSUSED*/ 1701 static int 1702 pipe_kqfilter(struct file *fp, struct knote *kn) 1703 { 1704 struct pipe *cpipe; 1705 1706 /* 1707 * If a filter is requested that is not supported by this file 1708 * descriptor, don't return an error, but also don't ever generate an 1709 * event. 1710 */ 1711 if ((kn->kn_filter == EVFILT_READ) && !(fp->f_flag & FREAD)) { 1712 kn->kn_fop = &pipe_nfiltops; 1713 return (0); 1714 } 1715 if ((kn->kn_filter == EVFILT_WRITE) && !(fp->f_flag & FWRITE)) { 1716 kn->kn_fop = &pipe_nfiltops; 1717 return (0); 1718 } 1719 cpipe = fp->f_data; 1720 PIPE_LOCK(cpipe); 1721 switch (kn->kn_filter) { 1722 case EVFILT_READ: 1723 kn->kn_fop = &pipe_rfiltops; 1724 break; 1725 case EVFILT_WRITE: 1726 kn->kn_fop = &pipe_wfiltops; 1727 if (cpipe->pipe_peer->pipe_present != PIPE_ACTIVE) { 1728 /* other end of pipe has been closed */ 1729 PIPE_UNLOCK(cpipe); 1730 return (EPIPE); 1731 } 1732 cpipe = PIPE_PEER(cpipe); 1733 break; 1734 default: 1735 PIPE_UNLOCK(cpipe); 1736 return (EINVAL); 1737 } 1738 1739 kn->kn_hook = cpipe; 1740 knlist_add(&cpipe->pipe_sel.si_note, kn, 1); 1741 PIPE_UNLOCK(cpipe); 1742 return (0); 1743 } 1744 1745 static void 1746 filt_pipedetach(struct knote *kn) 1747 { 1748 struct pipe *cpipe = kn->kn_hook; 1749 1750 PIPE_LOCK(cpipe); 1751 knlist_remove(&cpipe->pipe_sel.si_note, kn, 1); 1752 PIPE_UNLOCK(cpipe); 1753 } 1754 1755 /*ARGSUSED*/ 1756 static int 1757 filt_piperead(struct knote *kn, long hint) 1758 { 1759 struct pipe *rpipe = kn->kn_hook; 1760 struct pipe *wpipe = rpipe->pipe_peer; 1761 int ret; 1762 1763 PIPE_LOCK(rpipe); 1764 kn->kn_data = rpipe->pipe_buffer.cnt; 1765 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1766 kn->kn_data = rpipe->pipe_map.cnt; 1767 1768 if ((rpipe->pipe_state & PIPE_EOF) || 1769 wpipe->pipe_present != PIPE_ACTIVE || 1770 (wpipe->pipe_state & PIPE_EOF)) { 1771 kn->kn_flags |= EV_EOF; 1772 PIPE_UNLOCK(rpipe); 1773 return (1); 1774 } 1775 ret = kn->kn_data > 0; 1776 PIPE_UNLOCK(rpipe); 1777 return ret; 1778 } 1779 1780 /*ARGSUSED*/ 1781 static int 1782 filt_pipewrite(struct knote *kn, long hint) 1783 { 1784 struct pipe *wpipe; 1785 1786 wpipe = kn->kn_hook; 1787 PIPE_LOCK(wpipe); 1788 if (wpipe->pipe_present != PIPE_ACTIVE || 1789 (wpipe->pipe_state & PIPE_EOF)) { 1790 kn->kn_data = 0; 1791 kn->kn_flags |= EV_EOF; 1792 PIPE_UNLOCK(wpipe); 1793 return (1); 1794 } 1795 kn->kn_data = (wpipe->pipe_buffer.size > 0) ? 1796 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF; 1797 if (wpipe->pipe_state & PIPE_DIRECTW) 1798 kn->kn_data = 0; 1799 1800 PIPE_UNLOCK(wpipe); 1801 return (kn->kn_data >= PIPE_BUF); 1802 } 1803 1804 static void 1805 filt_pipedetach_notsup(struct knote *kn) 1806 { 1807 1808 } 1809 1810 static int 1811 filt_pipenotsup(struct knote *kn, long hint) 1812 { 1813 1814 return (0); 1815 } 1816