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 int 481 sys_pipe2(struct thread *td, struct pipe2_args *uap) 482 { 483 int error, fildes[2]; 484 485 if (uap->flags & ~(O_CLOEXEC | O_NONBLOCK)) 486 return (EINVAL); 487 error = kern_pipe2(td, fildes, uap->flags); 488 if (error) 489 return (error); 490 error = copyout(fildes, uap->fildes, 2 * sizeof(int)); 491 if (error) { 492 (void)kern_close(td, fildes[0]); 493 (void)kern_close(td, fildes[1]); 494 } 495 return (error); 496 } 497 498 /* 499 * Allocate kva for pipe circular buffer, the space is pageable 500 * This routine will 'realloc' the size of a pipe safely, if it fails 501 * it will retain the old buffer. 502 * If it fails it will return ENOMEM. 503 */ 504 static int 505 pipespace_new(cpipe, size) 506 struct pipe *cpipe; 507 int size; 508 { 509 caddr_t buffer; 510 int error, cnt, firstseg; 511 static int curfail = 0; 512 static struct timeval lastfail; 513 514 KASSERT(!mtx_owned(PIPE_MTX(cpipe)), ("pipespace: pipe mutex locked")); 515 KASSERT(!(cpipe->pipe_state & PIPE_DIRECTW), 516 ("pipespace: resize of direct writes not allowed")); 517 retry: 518 cnt = cpipe->pipe_buffer.cnt; 519 if (cnt > size) 520 size = cnt; 521 522 size = round_page(size); 523 buffer = (caddr_t) vm_map_min(pipe_map); 524 525 error = vm_map_find(pipe_map, NULL, 0, 526 (vm_offset_t *) &buffer, size, 1, 527 VM_PROT_ALL, VM_PROT_ALL, 0); 528 if (error != KERN_SUCCESS) { 529 if ((cpipe->pipe_buffer.buffer == NULL) && 530 (size > SMALL_PIPE_SIZE)) { 531 size = SMALL_PIPE_SIZE; 532 pipefragretry++; 533 goto retry; 534 } 535 if (cpipe->pipe_buffer.buffer == NULL) { 536 pipeallocfail++; 537 if (ppsratecheck(&lastfail, &curfail, 1)) 538 printf("kern.ipc.maxpipekva exceeded; see tuning(7)\n"); 539 } else { 540 piperesizefail++; 541 } 542 return (ENOMEM); 543 } 544 545 /* copy data, then free old resources if we're resizing */ 546 if (cnt > 0) { 547 if (cpipe->pipe_buffer.in <= cpipe->pipe_buffer.out) { 548 firstseg = cpipe->pipe_buffer.size - cpipe->pipe_buffer.out; 549 bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out], 550 buffer, firstseg); 551 if ((cnt - firstseg) > 0) 552 bcopy(cpipe->pipe_buffer.buffer, &buffer[firstseg], 553 cpipe->pipe_buffer.in); 554 } else { 555 bcopy(&cpipe->pipe_buffer.buffer[cpipe->pipe_buffer.out], 556 buffer, cnt); 557 } 558 } 559 pipe_free_kmem(cpipe); 560 cpipe->pipe_buffer.buffer = buffer; 561 cpipe->pipe_buffer.size = size; 562 cpipe->pipe_buffer.in = cnt; 563 cpipe->pipe_buffer.out = 0; 564 cpipe->pipe_buffer.cnt = cnt; 565 atomic_add_long(&amountpipekva, cpipe->pipe_buffer.size); 566 return (0); 567 } 568 569 /* 570 * Wrapper for pipespace_new() that performs locking assertions. 571 */ 572 static int 573 pipespace(cpipe, size) 574 struct pipe *cpipe; 575 int size; 576 { 577 578 KASSERT(cpipe->pipe_state & PIPE_LOCKFL, 579 ("Unlocked pipe passed to pipespace")); 580 return (pipespace_new(cpipe, size)); 581 } 582 583 /* 584 * lock a pipe for I/O, blocking other access 585 */ 586 static __inline int 587 pipelock(cpipe, catch) 588 struct pipe *cpipe; 589 int catch; 590 { 591 int error; 592 593 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 594 while (cpipe->pipe_state & PIPE_LOCKFL) { 595 cpipe->pipe_state |= PIPE_LWANT; 596 error = msleep(cpipe, PIPE_MTX(cpipe), 597 catch ? (PRIBIO | PCATCH) : PRIBIO, 598 "pipelk", 0); 599 if (error != 0) 600 return (error); 601 } 602 cpipe->pipe_state |= PIPE_LOCKFL; 603 return (0); 604 } 605 606 /* 607 * unlock a pipe I/O lock 608 */ 609 static __inline void 610 pipeunlock(cpipe) 611 struct pipe *cpipe; 612 { 613 614 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 615 KASSERT(cpipe->pipe_state & PIPE_LOCKFL, 616 ("Unlocked pipe passed to pipeunlock")); 617 cpipe->pipe_state &= ~PIPE_LOCKFL; 618 if (cpipe->pipe_state & PIPE_LWANT) { 619 cpipe->pipe_state &= ~PIPE_LWANT; 620 wakeup(cpipe); 621 } 622 } 623 624 void 625 pipeselwakeup(cpipe) 626 struct pipe *cpipe; 627 { 628 629 PIPE_LOCK_ASSERT(cpipe, MA_OWNED); 630 if (cpipe->pipe_state & PIPE_SEL) { 631 selwakeuppri(&cpipe->pipe_sel, PSOCK); 632 if (!SEL_WAITING(&cpipe->pipe_sel)) 633 cpipe->pipe_state &= ~PIPE_SEL; 634 } 635 if ((cpipe->pipe_state & PIPE_ASYNC) && cpipe->pipe_sigio) 636 pgsigio(&cpipe->pipe_sigio, SIGIO, 0); 637 KNOTE_LOCKED(&cpipe->pipe_sel.si_note, 0); 638 } 639 640 /* 641 * Initialize and allocate VM and memory for pipe. The structure 642 * will start out zero'd from the ctor, so we just manage the kmem. 643 */ 644 static int 645 pipe_create(pipe, backing) 646 struct pipe *pipe; 647 int backing; 648 { 649 int error; 650 651 if (backing) { 652 if (amountpipekva > maxpipekva / 2) 653 error = pipespace_new(pipe, SMALL_PIPE_SIZE); 654 else 655 error = pipespace_new(pipe, PIPE_SIZE); 656 } else { 657 /* If we're not backing this pipe, no need to do anything. */ 658 error = 0; 659 } 660 pipe->pipe_ino = -1; 661 return (error); 662 } 663 664 /* ARGSUSED */ 665 static int 666 pipe_read(fp, uio, active_cred, flags, td) 667 struct file *fp; 668 struct uio *uio; 669 struct ucred *active_cred; 670 struct thread *td; 671 int flags; 672 { 673 struct pipe *rpipe; 674 int error; 675 int nread = 0; 676 int size; 677 678 rpipe = fp->f_data; 679 PIPE_LOCK(rpipe); 680 ++rpipe->pipe_busy; 681 error = pipelock(rpipe, 1); 682 if (error) 683 goto unlocked_error; 684 685 #ifdef MAC 686 error = mac_pipe_check_read(active_cred, rpipe->pipe_pair); 687 if (error) 688 goto locked_error; 689 #endif 690 if (amountpipekva > (3 * maxpipekva) / 4) { 691 if (!(rpipe->pipe_state & PIPE_DIRECTW) && 692 (rpipe->pipe_buffer.size > SMALL_PIPE_SIZE) && 693 (rpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) && 694 (piperesizeallowed == 1)) { 695 PIPE_UNLOCK(rpipe); 696 pipespace(rpipe, SMALL_PIPE_SIZE); 697 PIPE_LOCK(rpipe); 698 } 699 } 700 701 while (uio->uio_resid) { 702 /* 703 * normal pipe buffer receive 704 */ 705 if (rpipe->pipe_buffer.cnt > 0) { 706 size = rpipe->pipe_buffer.size - rpipe->pipe_buffer.out; 707 if (size > rpipe->pipe_buffer.cnt) 708 size = rpipe->pipe_buffer.cnt; 709 if (size > uio->uio_resid) 710 size = uio->uio_resid; 711 712 PIPE_UNLOCK(rpipe); 713 error = uiomove( 714 &rpipe->pipe_buffer.buffer[rpipe->pipe_buffer.out], 715 size, uio); 716 PIPE_LOCK(rpipe); 717 if (error) 718 break; 719 720 rpipe->pipe_buffer.out += size; 721 if (rpipe->pipe_buffer.out >= rpipe->pipe_buffer.size) 722 rpipe->pipe_buffer.out = 0; 723 724 rpipe->pipe_buffer.cnt -= size; 725 726 /* 727 * If there is no more to read in the pipe, reset 728 * its pointers to the beginning. This improves 729 * cache hit stats. 730 */ 731 if (rpipe->pipe_buffer.cnt == 0) { 732 rpipe->pipe_buffer.in = 0; 733 rpipe->pipe_buffer.out = 0; 734 } 735 nread += size; 736 #ifndef PIPE_NODIRECT 737 /* 738 * Direct copy, bypassing a kernel buffer. 739 */ 740 } else if ((size = rpipe->pipe_map.cnt) && 741 (rpipe->pipe_state & PIPE_DIRECTW)) { 742 if (size > uio->uio_resid) 743 size = (u_int) uio->uio_resid; 744 745 PIPE_UNLOCK(rpipe); 746 error = uiomove_fromphys(rpipe->pipe_map.ms, 747 rpipe->pipe_map.pos, size, uio); 748 PIPE_LOCK(rpipe); 749 if (error) 750 break; 751 nread += size; 752 rpipe->pipe_map.pos += size; 753 rpipe->pipe_map.cnt -= size; 754 if (rpipe->pipe_map.cnt == 0) { 755 rpipe->pipe_state &= ~(PIPE_DIRECTW|PIPE_WANTW); 756 wakeup(rpipe); 757 } 758 #endif 759 } else { 760 /* 761 * detect EOF condition 762 * read returns 0 on EOF, no need to set error 763 */ 764 if (rpipe->pipe_state & PIPE_EOF) 765 break; 766 767 /* 768 * If the "write-side" has been blocked, wake it up now. 769 */ 770 if (rpipe->pipe_state & PIPE_WANTW) { 771 rpipe->pipe_state &= ~PIPE_WANTW; 772 wakeup(rpipe); 773 } 774 775 /* 776 * Break if some data was read. 777 */ 778 if (nread > 0) 779 break; 780 781 /* 782 * Unlock the pipe buffer for our remaining processing. 783 * We will either break out with an error or we will 784 * sleep and relock to loop. 785 */ 786 pipeunlock(rpipe); 787 788 /* 789 * Handle non-blocking mode operation or 790 * wait for more data. 791 */ 792 if (fp->f_flag & FNONBLOCK) { 793 error = EAGAIN; 794 } else { 795 rpipe->pipe_state |= PIPE_WANTR; 796 if ((error = msleep(rpipe, PIPE_MTX(rpipe), 797 PRIBIO | PCATCH, 798 "piperd", 0)) == 0) 799 error = pipelock(rpipe, 1); 800 } 801 if (error) 802 goto unlocked_error; 803 } 804 } 805 #ifdef MAC 806 locked_error: 807 #endif 808 pipeunlock(rpipe); 809 810 /* XXX: should probably do this before getting any locks. */ 811 if (error == 0) 812 vfs_timestamp(&rpipe->pipe_atime); 813 unlocked_error: 814 --rpipe->pipe_busy; 815 816 /* 817 * PIPE_WANT processing only makes sense if pipe_busy is 0. 818 */ 819 if ((rpipe->pipe_busy == 0) && (rpipe->pipe_state & PIPE_WANT)) { 820 rpipe->pipe_state &= ~(PIPE_WANT|PIPE_WANTW); 821 wakeup(rpipe); 822 } else if (rpipe->pipe_buffer.cnt < MINPIPESIZE) { 823 /* 824 * Handle write blocking hysteresis. 825 */ 826 if (rpipe->pipe_state & PIPE_WANTW) { 827 rpipe->pipe_state &= ~PIPE_WANTW; 828 wakeup(rpipe); 829 } 830 } 831 832 if ((rpipe->pipe_buffer.size - rpipe->pipe_buffer.cnt) >= PIPE_BUF) 833 pipeselwakeup(rpipe); 834 835 PIPE_UNLOCK(rpipe); 836 return (error); 837 } 838 839 #ifndef PIPE_NODIRECT 840 /* 841 * Map the sending processes' buffer into kernel space and wire it. 842 * This is similar to a physical write operation. 843 */ 844 static int 845 pipe_build_write_buffer(wpipe, uio) 846 struct pipe *wpipe; 847 struct uio *uio; 848 { 849 u_int size; 850 int i; 851 852 PIPE_LOCK_ASSERT(wpipe, MA_NOTOWNED); 853 KASSERT(wpipe->pipe_state & PIPE_DIRECTW, 854 ("Clone attempt on non-direct write pipe!")); 855 856 if (uio->uio_iov->iov_len > wpipe->pipe_buffer.size) 857 size = wpipe->pipe_buffer.size; 858 else 859 size = uio->uio_iov->iov_len; 860 861 if ((i = vm_fault_quick_hold_pages(&curproc->p_vmspace->vm_map, 862 (vm_offset_t)uio->uio_iov->iov_base, size, VM_PROT_READ, 863 wpipe->pipe_map.ms, PIPENPAGES)) < 0) 864 return (EFAULT); 865 866 /* 867 * set up the control block 868 */ 869 wpipe->pipe_map.npages = i; 870 wpipe->pipe_map.pos = 871 ((vm_offset_t) uio->uio_iov->iov_base) & PAGE_MASK; 872 wpipe->pipe_map.cnt = size; 873 874 /* 875 * and update the uio data 876 */ 877 878 uio->uio_iov->iov_len -= size; 879 uio->uio_iov->iov_base = (char *)uio->uio_iov->iov_base + size; 880 if (uio->uio_iov->iov_len == 0) 881 uio->uio_iov++; 882 uio->uio_resid -= size; 883 uio->uio_offset += size; 884 return (0); 885 } 886 887 /* 888 * unmap and unwire the process buffer 889 */ 890 static void 891 pipe_destroy_write_buffer(wpipe) 892 struct pipe *wpipe; 893 { 894 895 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 896 vm_page_unhold_pages(wpipe->pipe_map.ms, wpipe->pipe_map.npages); 897 wpipe->pipe_map.npages = 0; 898 } 899 900 /* 901 * In the case of a signal, the writing process might go away. This 902 * code copies the data into the circular buffer so that the source 903 * pages can be freed without loss of data. 904 */ 905 static void 906 pipe_clone_write_buffer(wpipe) 907 struct pipe *wpipe; 908 { 909 struct uio uio; 910 struct iovec iov; 911 int size; 912 int pos; 913 914 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 915 size = wpipe->pipe_map.cnt; 916 pos = wpipe->pipe_map.pos; 917 918 wpipe->pipe_buffer.in = size; 919 wpipe->pipe_buffer.out = 0; 920 wpipe->pipe_buffer.cnt = size; 921 wpipe->pipe_state &= ~PIPE_DIRECTW; 922 923 PIPE_UNLOCK(wpipe); 924 iov.iov_base = wpipe->pipe_buffer.buffer; 925 iov.iov_len = size; 926 uio.uio_iov = &iov; 927 uio.uio_iovcnt = 1; 928 uio.uio_offset = 0; 929 uio.uio_resid = size; 930 uio.uio_segflg = UIO_SYSSPACE; 931 uio.uio_rw = UIO_READ; 932 uio.uio_td = curthread; 933 uiomove_fromphys(wpipe->pipe_map.ms, pos, size, &uio); 934 PIPE_LOCK(wpipe); 935 pipe_destroy_write_buffer(wpipe); 936 } 937 938 /* 939 * This implements the pipe buffer write mechanism. Note that only 940 * a direct write OR a normal pipe write can be pending at any given time. 941 * If there are any characters in the pipe buffer, the direct write will 942 * be deferred until the receiving process grabs all of the bytes from 943 * the pipe buffer. Then the direct mapping write is set-up. 944 */ 945 static int 946 pipe_direct_write(wpipe, uio) 947 struct pipe *wpipe; 948 struct uio *uio; 949 { 950 int error; 951 952 retry: 953 PIPE_LOCK_ASSERT(wpipe, MA_OWNED); 954 error = pipelock(wpipe, 1); 955 if (wpipe->pipe_state & PIPE_EOF) 956 error = EPIPE; 957 if (error) { 958 pipeunlock(wpipe); 959 goto error1; 960 } 961 while (wpipe->pipe_state & PIPE_DIRECTW) { 962 if (wpipe->pipe_state & PIPE_WANTR) { 963 wpipe->pipe_state &= ~PIPE_WANTR; 964 wakeup(wpipe); 965 } 966 pipeselwakeup(wpipe); 967 wpipe->pipe_state |= PIPE_WANTW; 968 pipeunlock(wpipe); 969 error = msleep(wpipe, PIPE_MTX(wpipe), 970 PRIBIO | PCATCH, "pipdww", 0); 971 if (error) 972 goto error1; 973 else 974 goto retry; 975 } 976 wpipe->pipe_map.cnt = 0; /* transfer not ready yet */ 977 if (wpipe->pipe_buffer.cnt > 0) { 978 if (wpipe->pipe_state & PIPE_WANTR) { 979 wpipe->pipe_state &= ~PIPE_WANTR; 980 wakeup(wpipe); 981 } 982 pipeselwakeup(wpipe); 983 wpipe->pipe_state |= PIPE_WANTW; 984 pipeunlock(wpipe); 985 error = msleep(wpipe, PIPE_MTX(wpipe), 986 PRIBIO | PCATCH, "pipdwc", 0); 987 if (error) 988 goto error1; 989 else 990 goto retry; 991 } 992 993 wpipe->pipe_state |= PIPE_DIRECTW; 994 995 PIPE_UNLOCK(wpipe); 996 error = pipe_build_write_buffer(wpipe, uio); 997 PIPE_LOCK(wpipe); 998 if (error) { 999 wpipe->pipe_state &= ~PIPE_DIRECTW; 1000 pipeunlock(wpipe); 1001 goto error1; 1002 } 1003 1004 error = 0; 1005 while (!error && (wpipe->pipe_state & PIPE_DIRECTW)) { 1006 if (wpipe->pipe_state & PIPE_EOF) { 1007 pipe_destroy_write_buffer(wpipe); 1008 pipeselwakeup(wpipe); 1009 pipeunlock(wpipe); 1010 error = EPIPE; 1011 goto error1; 1012 } 1013 if (wpipe->pipe_state & PIPE_WANTR) { 1014 wpipe->pipe_state &= ~PIPE_WANTR; 1015 wakeup(wpipe); 1016 } 1017 pipeselwakeup(wpipe); 1018 wpipe->pipe_state |= PIPE_WANTW; 1019 pipeunlock(wpipe); 1020 error = msleep(wpipe, PIPE_MTX(wpipe), PRIBIO | PCATCH, 1021 "pipdwt", 0); 1022 pipelock(wpipe, 0); 1023 } 1024 1025 if (wpipe->pipe_state & PIPE_EOF) 1026 error = EPIPE; 1027 if (wpipe->pipe_state & PIPE_DIRECTW) { 1028 /* 1029 * this bit of trickery substitutes a kernel buffer for 1030 * the process that might be going away. 1031 */ 1032 pipe_clone_write_buffer(wpipe); 1033 } else { 1034 pipe_destroy_write_buffer(wpipe); 1035 } 1036 pipeunlock(wpipe); 1037 return (error); 1038 1039 error1: 1040 wakeup(wpipe); 1041 return (error); 1042 } 1043 #endif 1044 1045 static int 1046 pipe_write(fp, uio, active_cred, flags, td) 1047 struct file *fp; 1048 struct uio *uio; 1049 struct ucred *active_cred; 1050 struct thread *td; 1051 int flags; 1052 { 1053 int error = 0; 1054 int desiredsize; 1055 ssize_t orig_resid; 1056 struct pipe *wpipe, *rpipe; 1057 1058 rpipe = fp->f_data; 1059 wpipe = PIPE_PEER(rpipe); 1060 PIPE_LOCK(rpipe); 1061 error = pipelock(wpipe, 1); 1062 if (error) { 1063 PIPE_UNLOCK(rpipe); 1064 return (error); 1065 } 1066 /* 1067 * detect loss of pipe read side, issue SIGPIPE if lost. 1068 */ 1069 if (wpipe->pipe_present != PIPE_ACTIVE || 1070 (wpipe->pipe_state & PIPE_EOF)) { 1071 pipeunlock(wpipe); 1072 PIPE_UNLOCK(rpipe); 1073 return (EPIPE); 1074 } 1075 #ifdef MAC 1076 error = mac_pipe_check_write(active_cred, wpipe->pipe_pair); 1077 if (error) { 1078 pipeunlock(wpipe); 1079 PIPE_UNLOCK(rpipe); 1080 return (error); 1081 } 1082 #endif 1083 ++wpipe->pipe_busy; 1084 1085 /* Choose a larger size if it's advantageous */ 1086 desiredsize = max(SMALL_PIPE_SIZE, wpipe->pipe_buffer.size); 1087 while (desiredsize < wpipe->pipe_buffer.cnt + uio->uio_resid) { 1088 if (piperesizeallowed != 1) 1089 break; 1090 if (amountpipekva > maxpipekva / 2) 1091 break; 1092 if (desiredsize == BIG_PIPE_SIZE) 1093 break; 1094 desiredsize = desiredsize * 2; 1095 } 1096 1097 /* Choose a smaller size if we're in a OOM situation */ 1098 if ((amountpipekva > (3 * maxpipekva) / 4) && 1099 (wpipe->pipe_buffer.size > SMALL_PIPE_SIZE) && 1100 (wpipe->pipe_buffer.cnt <= SMALL_PIPE_SIZE) && 1101 (piperesizeallowed == 1)) 1102 desiredsize = SMALL_PIPE_SIZE; 1103 1104 /* Resize if the above determined that a new size was necessary */ 1105 if ((desiredsize != wpipe->pipe_buffer.size) && 1106 ((wpipe->pipe_state & PIPE_DIRECTW) == 0)) { 1107 PIPE_UNLOCK(wpipe); 1108 pipespace(wpipe, desiredsize); 1109 PIPE_LOCK(wpipe); 1110 } 1111 if (wpipe->pipe_buffer.size == 0) { 1112 /* 1113 * This can only happen for reverse direction use of pipes 1114 * in a complete OOM situation. 1115 */ 1116 error = ENOMEM; 1117 --wpipe->pipe_busy; 1118 pipeunlock(wpipe); 1119 PIPE_UNLOCK(wpipe); 1120 return (error); 1121 } 1122 1123 pipeunlock(wpipe); 1124 1125 orig_resid = uio->uio_resid; 1126 1127 while (uio->uio_resid) { 1128 int space; 1129 1130 pipelock(wpipe, 0); 1131 if (wpipe->pipe_state & PIPE_EOF) { 1132 pipeunlock(wpipe); 1133 error = EPIPE; 1134 break; 1135 } 1136 #ifndef PIPE_NODIRECT 1137 /* 1138 * If the transfer is large, we can gain performance if 1139 * we do process-to-process copies directly. 1140 * If the write is non-blocking, we don't use the 1141 * direct write mechanism. 1142 * 1143 * The direct write mechanism will detect the reader going 1144 * away on us. 1145 */ 1146 if (uio->uio_segflg == UIO_USERSPACE && 1147 uio->uio_iov->iov_len >= PIPE_MINDIRECT && 1148 wpipe->pipe_buffer.size >= PIPE_MINDIRECT && 1149 (fp->f_flag & FNONBLOCK) == 0) { 1150 pipeunlock(wpipe); 1151 error = pipe_direct_write(wpipe, uio); 1152 if (error) 1153 break; 1154 continue; 1155 } 1156 #endif 1157 1158 /* 1159 * Pipe buffered writes cannot be coincidental with 1160 * direct writes. We wait until the currently executing 1161 * direct write is completed before we start filling the 1162 * pipe buffer. We break out if a signal occurs or the 1163 * reader goes away. 1164 */ 1165 if (wpipe->pipe_state & PIPE_DIRECTW) { 1166 if (wpipe->pipe_state & PIPE_WANTR) { 1167 wpipe->pipe_state &= ~PIPE_WANTR; 1168 wakeup(wpipe); 1169 } 1170 pipeselwakeup(wpipe); 1171 wpipe->pipe_state |= PIPE_WANTW; 1172 pipeunlock(wpipe); 1173 error = msleep(wpipe, PIPE_MTX(rpipe), PRIBIO | PCATCH, 1174 "pipbww", 0); 1175 if (error) 1176 break; 1177 else 1178 continue; 1179 } 1180 1181 space = wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt; 1182 1183 /* Writes of size <= PIPE_BUF must be atomic. */ 1184 if ((space < uio->uio_resid) && (orig_resid <= PIPE_BUF)) 1185 space = 0; 1186 1187 if (space > 0) { 1188 int size; /* Transfer size */ 1189 int segsize; /* first segment to transfer */ 1190 1191 /* 1192 * Transfer size is minimum of uio transfer 1193 * and free space in pipe buffer. 1194 */ 1195 if (space > uio->uio_resid) 1196 size = uio->uio_resid; 1197 else 1198 size = space; 1199 /* 1200 * First segment to transfer is minimum of 1201 * transfer size and contiguous space in 1202 * pipe buffer. If first segment to transfer 1203 * is less than the transfer size, we've got 1204 * a wraparound in the buffer. 1205 */ 1206 segsize = wpipe->pipe_buffer.size - 1207 wpipe->pipe_buffer.in; 1208 if (segsize > size) 1209 segsize = size; 1210 1211 /* Transfer first segment */ 1212 1213 PIPE_UNLOCK(rpipe); 1214 error = uiomove(&wpipe->pipe_buffer.buffer[wpipe->pipe_buffer.in], 1215 segsize, uio); 1216 PIPE_LOCK(rpipe); 1217 1218 if (error == 0 && segsize < size) { 1219 KASSERT(wpipe->pipe_buffer.in + segsize == 1220 wpipe->pipe_buffer.size, 1221 ("Pipe buffer wraparound disappeared")); 1222 /* 1223 * Transfer remaining part now, to 1224 * support atomic writes. Wraparound 1225 * happened. 1226 */ 1227 1228 PIPE_UNLOCK(rpipe); 1229 error = uiomove( 1230 &wpipe->pipe_buffer.buffer[0], 1231 size - segsize, uio); 1232 PIPE_LOCK(rpipe); 1233 } 1234 if (error == 0) { 1235 wpipe->pipe_buffer.in += size; 1236 if (wpipe->pipe_buffer.in >= 1237 wpipe->pipe_buffer.size) { 1238 KASSERT(wpipe->pipe_buffer.in == 1239 size - segsize + 1240 wpipe->pipe_buffer.size, 1241 ("Expected wraparound bad")); 1242 wpipe->pipe_buffer.in = size - segsize; 1243 } 1244 1245 wpipe->pipe_buffer.cnt += size; 1246 KASSERT(wpipe->pipe_buffer.cnt <= 1247 wpipe->pipe_buffer.size, 1248 ("Pipe buffer overflow")); 1249 } 1250 pipeunlock(wpipe); 1251 if (error != 0) 1252 break; 1253 } else { 1254 /* 1255 * If the "read-side" has been blocked, wake it up now. 1256 */ 1257 if (wpipe->pipe_state & PIPE_WANTR) { 1258 wpipe->pipe_state &= ~PIPE_WANTR; 1259 wakeup(wpipe); 1260 } 1261 1262 /* 1263 * don't block on non-blocking I/O 1264 */ 1265 if (fp->f_flag & FNONBLOCK) { 1266 error = EAGAIN; 1267 pipeunlock(wpipe); 1268 break; 1269 } 1270 1271 /* 1272 * We have no more space and have something to offer, 1273 * wake up select/poll. 1274 */ 1275 pipeselwakeup(wpipe); 1276 1277 wpipe->pipe_state |= PIPE_WANTW; 1278 pipeunlock(wpipe); 1279 error = msleep(wpipe, PIPE_MTX(rpipe), 1280 PRIBIO | PCATCH, "pipewr", 0); 1281 if (error != 0) 1282 break; 1283 } 1284 } 1285 1286 pipelock(wpipe, 0); 1287 --wpipe->pipe_busy; 1288 1289 if ((wpipe->pipe_busy == 0) && (wpipe->pipe_state & PIPE_WANT)) { 1290 wpipe->pipe_state &= ~(PIPE_WANT | PIPE_WANTR); 1291 wakeup(wpipe); 1292 } else if (wpipe->pipe_buffer.cnt > 0) { 1293 /* 1294 * If we have put any characters in the buffer, we wake up 1295 * the reader. 1296 */ 1297 if (wpipe->pipe_state & PIPE_WANTR) { 1298 wpipe->pipe_state &= ~PIPE_WANTR; 1299 wakeup(wpipe); 1300 } 1301 } 1302 1303 /* 1304 * Don't return EPIPE if I/O was successful 1305 */ 1306 if ((wpipe->pipe_buffer.cnt == 0) && 1307 (uio->uio_resid == 0) && 1308 (error == EPIPE)) { 1309 error = 0; 1310 } 1311 1312 if (error == 0) 1313 vfs_timestamp(&wpipe->pipe_mtime); 1314 1315 /* 1316 * We have something to offer, 1317 * wake up select/poll. 1318 */ 1319 if (wpipe->pipe_buffer.cnt) 1320 pipeselwakeup(wpipe); 1321 1322 pipeunlock(wpipe); 1323 PIPE_UNLOCK(rpipe); 1324 return (error); 1325 } 1326 1327 /* ARGSUSED */ 1328 static int 1329 pipe_truncate(fp, length, active_cred, td) 1330 struct file *fp; 1331 off_t length; 1332 struct ucred *active_cred; 1333 struct thread *td; 1334 { 1335 1336 /* For named pipes call the vnode operation. */ 1337 if (fp->f_vnode != NULL) 1338 return (vnops.fo_truncate(fp, length, active_cred, td)); 1339 return (EINVAL); 1340 } 1341 1342 /* 1343 * we implement a very minimal set of ioctls for compatibility with sockets. 1344 */ 1345 static int 1346 pipe_ioctl(fp, cmd, data, active_cred, td) 1347 struct file *fp; 1348 u_long cmd; 1349 void *data; 1350 struct ucred *active_cred; 1351 struct thread *td; 1352 { 1353 struct pipe *mpipe = fp->f_data; 1354 int error; 1355 1356 PIPE_LOCK(mpipe); 1357 1358 #ifdef MAC 1359 error = mac_pipe_check_ioctl(active_cred, mpipe->pipe_pair, cmd, data); 1360 if (error) { 1361 PIPE_UNLOCK(mpipe); 1362 return (error); 1363 } 1364 #endif 1365 1366 error = 0; 1367 switch (cmd) { 1368 1369 case FIONBIO: 1370 break; 1371 1372 case FIOASYNC: 1373 if (*(int *)data) { 1374 mpipe->pipe_state |= PIPE_ASYNC; 1375 } else { 1376 mpipe->pipe_state &= ~PIPE_ASYNC; 1377 } 1378 break; 1379 1380 case FIONREAD: 1381 if (!(fp->f_flag & FREAD)) { 1382 *(int *)data = 0; 1383 PIPE_UNLOCK(mpipe); 1384 return (0); 1385 } 1386 if (mpipe->pipe_state & PIPE_DIRECTW) 1387 *(int *)data = mpipe->pipe_map.cnt; 1388 else 1389 *(int *)data = mpipe->pipe_buffer.cnt; 1390 break; 1391 1392 case FIOSETOWN: 1393 PIPE_UNLOCK(mpipe); 1394 error = fsetown(*(int *)data, &mpipe->pipe_sigio); 1395 goto out_unlocked; 1396 1397 case FIOGETOWN: 1398 *(int *)data = fgetown(&mpipe->pipe_sigio); 1399 break; 1400 1401 /* This is deprecated, FIOSETOWN should be used instead. */ 1402 case TIOCSPGRP: 1403 PIPE_UNLOCK(mpipe); 1404 error = fsetown(-(*(int *)data), &mpipe->pipe_sigio); 1405 goto out_unlocked; 1406 1407 /* This is deprecated, FIOGETOWN should be used instead. */ 1408 case TIOCGPGRP: 1409 *(int *)data = -fgetown(&mpipe->pipe_sigio); 1410 break; 1411 1412 default: 1413 error = ENOTTY; 1414 break; 1415 } 1416 PIPE_UNLOCK(mpipe); 1417 out_unlocked: 1418 return (error); 1419 } 1420 1421 static int 1422 pipe_poll(fp, events, active_cred, td) 1423 struct file *fp; 1424 int events; 1425 struct ucred *active_cred; 1426 struct thread *td; 1427 { 1428 struct pipe *rpipe; 1429 struct pipe *wpipe; 1430 int levents, revents; 1431 #ifdef MAC 1432 int error; 1433 #endif 1434 1435 revents = 0; 1436 rpipe = fp->f_data; 1437 wpipe = PIPE_PEER(rpipe); 1438 PIPE_LOCK(rpipe); 1439 #ifdef MAC 1440 error = mac_pipe_check_poll(active_cred, rpipe->pipe_pair); 1441 if (error) 1442 goto locked_error; 1443 #endif 1444 if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM)) 1445 if ((rpipe->pipe_state & PIPE_DIRECTW) || 1446 (rpipe->pipe_buffer.cnt > 0)) 1447 revents |= events & (POLLIN | POLLRDNORM); 1448 1449 if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM)) 1450 if (wpipe->pipe_present != PIPE_ACTIVE || 1451 (wpipe->pipe_state & PIPE_EOF) || 1452 (((wpipe->pipe_state & PIPE_DIRECTW) == 0) && 1453 ((wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) >= PIPE_BUF || 1454 wpipe->pipe_buffer.size == 0))) 1455 revents |= events & (POLLOUT | POLLWRNORM); 1456 1457 levents = events & 1458 (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND); 1459 if (rpipe->pipe_state & PIPE_NAMED && fp->f_flag & FREAD && levents && 1460 fp->f_seqcount == rpipe->pipe_wgen) 1461 events |= POLLINIGNEOF; 1462 1463 if ((events & POLLINIGNEOF) == 0) { 1464 if (rpipe->pipe_state & PIPE_EOF) { 1465 revents |= (events & (POLLIN | POLLRDNORM)); 1466 if (wpipe->pipe_present != PIPE_ACTIVE || 1467 (wpipe->pipe_state & PIPE_EOF)) 1468 revents |= POLLHUP; 1469 } 1470 } 1471 1472 if (revents == 0) { 1473 if (fp->f_flag & FREAD && events & (POLLIN | POLLRDNORM)) { 1474 selrecord(td, &rpipe->pipe_sel); 1475 if (SEL_WAITING(&rpipe->pipe_sel)) 1476 rpipe->pipe_state |= PIPE_SEL; 1477 } 1478 1479 if (fp->f_flag & FWRITE && events & (POLLOUT | POLLWRNORM)) { 1480 selrecord(td, &wpipe->pipe_sel); 1481 if (SEL_WAITING(&wpipe->pipe_sel)) 1482 wpipe->pipe_state |= PIPE_SEL; 1483 } 1484 } 1485 #ifdef MAC 1486 locked_error: 1487 #endif 1488 PIPE_UNLOCK(rpipe); 1489 1490 return (revents); 1491 } 1492 1493 /* 1494 * We shouldn't need locks here as we're doing a read and this should 1495 * be a natural race. 1496 */ 1497 static int 1498 pipe_stat(fp, ub, active_cred, td) 1499 struct file *fp; 1500 struct stat *ub; 1501 struct ucred *active_cred; 1502 struct thread *td; 1503 { 1504 struct pipe *pipe; 1505 int new_unr; 1506 #ifdef MAC 1507 int error; 1508 #endif 1509 1510 pipe = fp->f_data; 1511 PIPE_LOCK(pipe); 1512 #ifdef MAC 1513 error = mac_pipe_check_stat(active_cred, pipe->pipe_pair); 1514 if (error) { 1515 PIPE_UNLOCK(pipe); 1516 return (error); 1517 } 1518 #endif 1519 1520 /* For named pipes ask the underlying filesystem. */ 1521 if (pipe->pipe_state & PIPE_NAMED) { 1522 PIPE_UNLOCK(pipe); 1523 return (vnops.fo_stat(fp, ub, active_cred, td)); 1524 } 1525 1526 /* 1527 * Lazily allocate an inode number for the pipe. Most pipe 1528 * users do not call fstat(2) on the pipe, which means that 1529 * postponing the inode allocation until it is must be 1530 * returned to userland is useful. If alloc_unr failed, 1531 * assign st_ino zero instead of returning an error. 1532 * Special pipe_ino values: 1533 * -1 - not yet initialized; 1534 * 0 - alloc_unr failed, return 0 as st_ino forever. 1535 */ 1536 if (pipe->pipe_ino == (ino_t)-1) { 1537 new_unr = alloc_unr(pipeino_unr); 1538 if (new_unr != -1) 1539 pipe->pipe_ino = new_unr; 1540 else 1541 pipe->pipe_ino = 0; 1542 } 1543 PIPE_UNLOCK(pipe); 1544 1545 bzero(ub, sizeof(*ub)); 1546 ub->st_mode = S_IFIFO; 1547 ub->st_blksize = PAGE_SIZE; 1548 if (pipe->pipe_state & PIPE_DIRECTW) 1549 ub->st_size = pipe->pipe_map.cnt; 1550 else 1551 ub->st_size = pipe->pipe_buffer.cnt; 1552 ub->st_blocks = (ub->st_size + ub->st_blksize - 1) / ub->st_blksize; 1553 ub->st_atim = pipe->pipe_atime; 1554 ub->st_mtim = pipe->pipe_mtime; 1555 ub->st_ctim = pipe->pipe_ctime; 1556 ub->st_uid = fp->f_cred->cr_uid; 1557 ub->st_gid = fp->f_cred->cr_gid; 1558 ub->st_dev = pipedev_ino; 1559 ub->st_ino = pipe->pipe_ino; 1560 /* 1561 * Left as 0: st_nlink, st_rdev, st_flags, st_gen. 1562 */ 1563 return (0); 1564 } 1565 1566 /* ARGSUSED */ 1567 static int 1568 pipe_close(fp, td) 1569 struct file *fp; 1570 struct thread *td; 1571 { 1572 1573 if (fp->f_vnode != NULL) 1574 return vnops.fo_close(fp, td); 1575 fp->f_ops = &badfileops; 1576 pipe_dtor(fp->f_data); 1577 fp->f_data = NULL; 1578 return (0); 1579 } 1580 1581 static int 1582 pipe_chmod(struct file *fp, mode_t mode, struct ucred *active_cred, struct thread *td) 1583 { 1584 struct pipe *cpipe; 1585 int error; 1586 1587 cpipe = fp->f_data; 1588 if (cpipe->pipe_state & PIPE_NAMED) 1589 error = vn_chmod(fp, mode, active_cred, td); 1590 else 1591 error = invfo_chmod(fp, mode, active_cred, td); 1592 return (error); 1593 } 1594 1595 static int 1596 pipe_chown(fp, uid, gid, active_cred, td) 1597 struct file *fp; 1598 uid_t uid; 1599 gid_t gid; 1600 struct ucred *active_cred; 1601 struct thread *td; 1602 { 1603 struct pipe *cpipe; 1604 int error; 1605 1606 cpipe = fp->f_data; 1607 if (cpipe->pipe_state & PIPE_NAMED) 1608 error = vn_chown(fp, uid, gid, active_cred, td); 1609 else 1610 error = invfo_chown(fp, uid, gid, active_cred, td); 1611 return (error); 1612 } 1613 1614 static void 1615 pipe_free_kmem(cpipe) 1616 struct pipe *cpipe; 1617 { 1618 1619 KASSERT(!mtx_owned(PIPE_MTX(cpipe)), 1620 ("pipe_free_kmem: pipe mutex locked")); 1621 1622 if (cpipe->pipe_buffer.buffer != NULL) { 1623 atomic_subtract_long(&amountpipekva, cpipe->pipe_buffer.size); 1624 vm_map_remove(pipe_map, 1625 (vm_offset_t)cpipe->pipe_buffer.buffer, 1626 (vm_offset_t)cpipe->pipe_buffer.buffer + cpipe->pipe_buffer.size); 1627 cpipe->pipe_buffer.buffer = NULL; 1628 } 1629 #ifndef PIPE_NODIRECT 1630 { 1631 cpipe->pipe_map.cnt = 0; 1632 cpipe->pipe_map.pos = 0; 1633 cpipe->pipe_map.npages = 0; 1634 } 1635 #endif 1636 } 1637 1638 /* 1639 * shutdown the pipe 1640 */ 1641 static void 1642 pipeclose(cpipe) 1643 struct pipe *cpipe; 1644 { 1645 struct pipepair *pp; 1646 struct pipe *ppipe; 1647 1648 KASSERT(cpipe != NULL, ("pipeclose: cpipe == NULL")); 1649 1650 PIPE_LOCK(cpipe); 1651 pipelock(cpipe, 0); 1652 pp = cpipe->pipe_pair; 1653 1654 pipeselwakeup(cpipe); 1655 1656 /* 1657 * If the other side is blocked, wake it up saying that 1658 * we want to close it down. 1659 */ 1660 cpipe->pipe_state |= PIPE_EOF; 1661 while (cpipe->pipe_busy) { 1662 wakeup(cpipe); 1663 cpipe->pipe_state |= PIPE_WANT; 1664 pipeunlock(cpipe); 1665 msleep(cpipe, PIPE_MTX(cpipe), PRIBIO, "pipecl", 0); 1666 pipelock(cpipe, 0); 1667 } 1668 1669 1670 /* 1671 * Disconnect from peer, if any. 1672 */ 1673 ppipe = cpipe->pipe_peer; 1674 if (ppipe->pipe_present == PIPE_ACTIVE) { 1675 pipeselwakeup(ppipe); 1676 1677 ppipe->pipe_state |= PIPE_EOF; 1678 wakeup(ppipe); 1679 KNOTE_LOCKED(&ppipe->pipe_sel.si_note, 0); 1680 } 1681 1682 /* 1683 * Mark this endpoint as free. Release kmem resources. We 1684 * don't mark this endpoint as unused until we've finished 1685 * doing that, or the pipe might disappear out from under 1686 * us. 1687 */ 1688 PIPE_UNLOCK(cpipe); 1689 pipe_free_kmem(cpipe); 1690 PIPE_LOCK(cpipe); 1691 cpipe->pipe_present = PIPE_CLOSING; 1692 pipeunlock(cpipe); 1693 1694 /* 1695 * knlist_clear() may sleep dropping the PIPE_MTX. Set the 1696 * PIPE_FINALIZED, that allows other end to free the 1697 * pipe_pair, only after the knotes are completely dismantled. 1698 */ 1699 knlist_clear(&cpipe->pipe_sel.si_note, 1); 1700 cpipe->pipe_present = PIPE_FINALIZED; 1701 seldrain(&cpipe->pipe_sel); 1702 knlist_destroy(&cpipe->pipe_sel.si_note); 1703 1704 /* 1705 * If both endpoints are now closed, release the memory for the 1706 * pipe pair. If not, unlock. 1707 */ 1708 if (ppipe->pipe_present == PIPE_FINALIZED) { 1709 PIPE_UNLOCK(cpipe); 1710 #ifdef MAC 1711 mac_pipe_destroy(pp); 1712 #endif 1713 uma_zfree(pipe_zone, cpipe->pipe_pair); 1714 } else 1715 PIPE_UNLOCK(cpipe); 1716 } 1717 1718 /*ARGSUSED*/ 1719 static int 1720 pipe_kqfilter(struct file *fp, struct knote *kn) 1721 { 1722 struct pipe *cpipe; 1723 1724 /* 1725 * If a filter is requested that is not supported by this file 1726 * descriptor, don't return an error, but also don't ever generate an 1727 * event. 1728 */ 1729 if ((kn->kn_filter == EVFILT_READ) && !(fp->f_flag & FREAD)) { 1730 kn->kn_fop = &pipe_nfiltops; 1731 return (0); 1732 } 1733 if ((kn->kn_filter == EVFILT_WRITE) && !(fp->f_flag & FWRITE)) { 1734 kn->kn_fop = &pipe_nfiltops; 1735 return (0); 1736 } 1737 cpipe = fp->f_data; 1738 PIPE_LOCK(cpipe); 1739 switch (kn->kn_filter) { 1740 case EVFILT_READ: 1741 kn->kn_fop = &pipe_rfiltops; 1742 break; 1743 case EVFILT_WRITE: 1744 kn->kn_fop = &pipe_wfiltops; 1745 if (cpipe->pipe_peer->pipe_present != PIPE_ACTIVE) { 1746 /* other end of pipe has been closed */ 1747 PIPE_UNLOCK(cpipe); 1748 return (EPIPE); 1749 } 1750 cpipe = PIPE_PEER(cpipe); 1751 break; 1752 default: 1753 PIPE_UNLOCK(cpipe); 1754 return (EINVAL); 1755 } 1756 1757 kn->kn_hook = cpipe; 1758 knlist_add(&cpipe->pipe_sel.si_note, kn, 1); 1759 PIPE_UNLOCK(cpipe); 1760 return (0); 1761 } 1762 1763 static void 1764 filt_pipedetach(struct knote *kn) 1765 { 1766 struct pipe *cpipe = kn->kn_hook; 1767 1768 PIPE_LOCK(cpipe); 1769 knlist_remove(&cpipe->pipe_sel.si_note, kn, 1); 1770 PIPE_UNLOCK(cpipe); 1771 } 1772 1773 /*ARGSUSED*/ 1774 static int 1775 filt_piperead(struct knote *kn, long hint) 1776 { 1777 struct pipe *rpipe = kn->kn_hook; 1778 struct pipe *wpipe = rpipe->pipe_peer; 1779 int ret; 1780 1781 PIPE_LOCK(rpipe); 1782 kn->kn_data = rpipe->pipe_buffer.cnt; 1783 if ((kn->kn_data == 0) && (rpipe->pipe_state & PIPE_DIRECTW)) 1784 kn->kn_data = rpipe->pipe_map.cnt; 1785 1786 if ((rpipe->pipe_state & PIPE_EOF) || 1787 wpipe->pipe_present != PIPE_ACTIVE || 1788 (wpipe->pipe_state & PIPE_EOF)) { 1789 kn->kn_flags |= EV_EOF; 1790 PIPE_UNLOCK(rpipe); 1791 return (1); 1792 } 1793 ret = kn->kn_data > 0; 1794 PIPE_UNLOCK(rpipe); 1795 return ret; 1796 } 1797 1798 /*ARGSUSED*/ 1799 static int 1800 filt_pipewrite(struct knote *kn, long hint) 1801 { 1802 struct pipe *wpipe; 1803 1804 wpipe = kn->kn_hook; 1805 PIPE_LOCK(wpipe); 1806 if (wpipe->pipe_present != PIPE_ACTIVE || 1807 (wpipe->pipe_state & PIPE_EOF)) { 1808 kn->kn_data = 0; 1809 kn->kn_flags |= EV_EOF; 1810 PIPE_UNLOCK(wpipe); 1811 return (1); 1812 } 1813 kn->kn_data = (wpipe->pipe_buffer.size > 0) ? 1814 (wpipe->pipe_buffer.size - wpipe->pipe_buffer.cnt) : PIPE_BUF; 1815 if (wpipe->pipe_state & PIPE_DIRECTW) 1816 kn->kn_data = 0; 1817 1818 PIPE_UNLOCK(wpipe); 1819 return (kn->kn_data >= PIPE_BUF); 1820 } 1821 1822 static void 1823 filt_pipedetach_notsup(struct knote *kn) 1824 { 1825 1826 } 1827 1828 static int 1829 filt_pipenotsup(struct knote *kn, long hint) 1830 { 1831 1832 return (0); 1833 } 1834