bsd/miscfs/fifofs/fifo_vnops.c

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  29 /*
  30  * Copyright (c) 1990, 1993, 1995
  31  *      The Regents of the University of California.  All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  * 3. All advertising materials mentioning features or use of this software
  42  *    must display the following acknowledgement:
  43  *      This product includes software developed by the University of
  44  *      California, Berkeley and its contributors.
  45  * 4. Neither the name of the University nor the names of its contributors
  46  *    may be used to endorse or promote products derived from this software
  47  *    without specific prior written permission.
  48  *
  49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  59  * SUCH DAMAGE.
  60  *
  61  *      @(#)fifo_vnops.c        8.4 (Berkeley) 8/10/94
  62  */
  63
  64 #include <sys/param.h>
  65 #include <sys/proc.h>
  66 #include <sys/time.h>
  67 #include <sys/namei.h>
  68 #include <sys/vnode_internal.h>
  69 #include <sys/socket.h>
  70 #include <sys/socketvar.h>
  71 #include <sys/stat.h>
  72 #include <sys/systm.h>
  73 #include <sys/ioctl.h>
  74 #include <sys/file_internal.h>
  75 #include <sys/errno.h>
  76 #include <sys/malloc.h>
  77 #include <miscfs/fifofs/fifo.h>
  78 #include <vfs/vfs_support.h>
  79
  80 #define VOPFUNC int (*)(void *)
  81
  82 int (**fifo_vnodeop_p)(void *);
  83 struct vnodeopv_entry_desc fifo_vnodeop_entries[] = {
  84         { &vnop_default_desc, (VOPFUNC)vn_default_error },
  85         { &vnop_lookup_desc, (VOPFUNC)fifo_lookup },            /* lookup */
  86         { &vnop_create_desc, (VOPFUNC)err_create },             /* create */
  87         { &vnop_mknod_desc, (VOPFUNC)err_mknod },               /* mknod */
  88         { &vnop_open_desc, (VOPFUNC)fifo_open },                        /* open */
  89         { &vnop_close_desc, (VOPFUNC)fifo_close },              /* close */
  90         { &vnop_access_desc, (VOPFUNC)fifo_access },            /* access */
  91         { &vnop_getattr_desc, (VOPFUNC)fifo_getattr },          /* getattr */
  92         { &vnop_setattr_desc, (VOPFUNC)fifo_setattr },          /* setattr */
  93         { &vnop_read_desc, (VOPFUNC)fifo_read },                        /* read */
  94         { &vnop_write_desc, (VOPFUNC)fifo_write },              /* write */
  95         { &vnop_ioctl_desc, (VOPFUNC)fifo_ioctl },              /* ioctl */
  96         { &vnop_select_desc, (VOPFUNC)fifo_select },            /* select */
  97         { &vnop_revoke_desc, (VOPFUNC)fifo_revoke },            /* revoke */
  98         { &vnop_mmap_desc, (VOPFUNC)err_mmap },                 /* mmap */
  99         { &vnop_fsync_desc, (VOPFUNC)fifo_fsync },              /* fsync */
 100         { &vnop_remove_desc, (VOPFUNC)err_remove },             /* remove */
 101         { &vnop_link_desc, (VOPFUNC)err_link },                 /* link */
 102         { &vnop_rename_desc, (VOPFUNC)err_rename },             /* rename */
 103         { &vnop_mkdir_desc, (VOPFUNC)err_mkdir },               /* mkdir */
 104         { &vnop_rmdir_desc, (VOPFUNC)err_rmdir },               /* rmdir */
 105         { &vnop_symlink_desc, (VOPFUNC)err_symlink },           /* symlink */
 106         { &vnop_readdir_desc, (VOPFUNC)err_readdir },           /* readdir */
 107         { &vnop_readlink_desc, (VOPFUNC)err_readlink },         /* readlink */
 108         { &vnop_inactive_desc, (VOPFUNC)fifo_inactive },                /* inactive */
 109         { &vnop_reclaim_desc, (VOPFUNC)fifo_reclaim },          /* reclaim */
 110         { &vnop_strategy_desc, (VOPFUNC)err_strategy },         /* strategy */
 111         { &vnop_pathconf_desc, (VOPFUNC)fifo_pathconf },                /* pathconf */
 112         { &vnop_advlock_desc, (VOPFUNC)fifo_advlock },          /* advlock */
 113         { &vnop_bwrite_desc, (VOPFUNC)fifo_bwrite },            /* bwrite */
 114         { &vnop_pagein_desc, (VOPFUNC)err_pagein },             /* Pagein */
 115         { &vnop_pageout_desc, (VOPFUNC)err_pageout },           /* Pageout */
 116         { &vnop_copyfile_desc, (VOPFUNC)err_copyfile },         /* Copyfile */
 117         { &vnop_blktooff_desc, (VOPFUNC)err_blktooff },         /* blktooff */
 118         { &vnop_offtoblk_desc, (VOPFUNC)err_offtoblk },         /* offtoblk */
 119         { &vnop_blockmap_desc, (VOPFUNC)err_blockmap },                 /* blockmap */
 120         { (struct vnodeop_desc*)NULL, (int(*)(void *))NULL }
 121 };
 122 struct vnodeopv_desc fifo_vnodeop_opv_desc =
 123         { &fifo_vnodeop_p, fifo_vnodeop_entries };
 124
 125 /*
 126  * Trivial lookup routine that always fails.
 127  */
 128 /* ARGSUSED */
 129 int
 130 fifo_lookup(struct vnop_lookup_args *ap)
 131 {
 132
 133         *ap->a_vpp = NULL;
 134         return (ENOTDIR);
 135 }
 136
 137 /*
 138  * Open called to set up a new instance of a fifo or
 139  * to find an active instance of a fifo.
 140  */
 141 /* ARGSUSED */
 142 int
 143 fifo_open(struct vnop_open_args *ap)
 144 {
 145         struct vnode *vp = ap->a_vp;
 146         struct fifoinfo *fip;
 147         struct socket *rso, *wso;
 148         int error;
 149
 150         vnode_lock(vp);
 151
 152 retry:
 153
 154         fip = vp->v_fifoinfo;
 155
 156         if (fip == (struct fifoinfo *)0)
 157                 panic("fifo_open with no fifoinfo");
 158
 159         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 160                 if (fip->fi_flags & FIFO_INCREATE) {
 161                         fip->fi_flags |= FIFO_CREATEWAIT;
 162                         error = msleep(&fip->fi_flags, &vp->v_lock, PRIBIO | PCATCH, "fifocreatewait", NULL);
 163                         if (error) {
 164                                 vnode_unlock(vp);
 165                                 return(error);
 166                         }
 167                         goto retry;
 168                 } else {
 169                         fip->fi_flags |= FIFO_INCREATE;
 170                         vnode_unlock(vp);
 171                         if ( (error = socreate(AF_LOCAL, &rso, SOCK_STREAM, 0)) ) {
 172                                 goto bad1;
 173                         }
 174
 175                         if ( (error = socreate(AF_LOCAL, &wso, SOCK_STREAM, 0)) ) {
 176                                 (void)soclose(rso);
 177                                 goto bad1;
 178                         }
 179
 180                         if ( (error = soconnect2(wso, rso)) ) {
 181                                 (void)soclose(wso);
 182                                 (void)soclose(rso);
 183                                 goto bad1;
 184                         }
 185                         fip->fi_readers = fip->fi_writers = 0;
 186
 187                         /* Lock ordering between wso and rso does not matter here
 188                          * because they are just created and no one has a reference to them
 189                          */
 190                         socket_lock(wso, 1);
 191                         wso->so_state |= SS_CANTRCVMORE;
 192                         wso->so_snd.sb_lowat = PIPE_BUF;
 193                         socket_unlock(wso, 1);
 194
 195                         socket_lock(rso, 1);
 196                         rso->so_state |= SS_CANTSENDMORE;
 197                         socket_unlock(rso, 1);
 198
 199                         vnode_lock(vp);
 200                         fip->fi_readsock = rso;
 201                         fip->fi_writesock = wso;
 202
 203                         fip->fi_flags |= FIFO_CREATED;
 204                         fip->fi_flags &= ~FIFO_INCREATE;
 205
 206                         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 207                                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 208                                 wakeup(&fip->fi_flags);
 209                         }
 210                         /* vnode lock is held  to process further */
 211                 }
 212         }
 213
 214         /* vnode is locked at this point */
 215         /* fifo in created already */
 216         if (ap->a_mode & FREAD) {
 217                 fip->fi_readers++;
 218                 if (fip->fi_readers == 1) {
 219                         socket_lock(fip->fi_writesock, 1);
 220                         fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
 221                         socket_unlock(fip->fi_writesock, 1);
 222
 223                         if (fip->fi_writers > 0)
 224                                 wakeup((caddr_t)&fip->fi_writers);
 225                 }
 226         }
 227         if (ap->a_mode & FWRITE) {
 228                 fip->fi_writers++;
 229                 if (fip->fi_writers == 1) {
 230                         socket_lock(fip->fi_readsock, 1);
 231                         fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
 232                         socket_unlock(fip->fi_readsock, 1);
 233
 234                         if (fip->fi_readers > 0)
 235                                 wakeup((caddr_t)&fip->fi_readers);
 236                 }
 237         }
 238         if ((ap->a_mode & FREAD) && (ap->a_mode & O_NONBLOCK) == 0) {
 239                 if (fip->fi_writers == 0) {
 240                         error = msleep((caddr_t)&fip->fi_readers, &vp->v_lock,
 241                                         PCATCH | PSOCK, "fifoor", NULL);
 242                         if (error)
 243                                 goto bad;
 244                         if (fip->fi_readers == 1) {
 245                                 if (fip->fi_writers > 0)
 246                                         wakeup((caddr_t)&fip->fi_writers);
 247                         }
 248                 }
 249         }
 250         if (ap->a_mode & FWRITE) {
 251                 if (ap->a_mode & O_NONBLOCK) {
 252                         if (fip->fi_readers == 0) {
 253                                         error = ENXIO;
 254                                         goto bad;
 255                         }
 256                 } else {
 257                         if (fip->fi_readers == 0) {
 258                                 error = msleep((caddr_t)&fip->fi_writers,&vp->v_lock,
 259                                                 PCATCH | PSOCK, "fifoow", NULL);
 260                                 if (error)
 261                                         goto bad;
 262                                 if (fip->fi_writers == 1) {
 263                                         if (fip->fi_readers > 0)
 264                                                 wakeup((caddr_t)&fip->fi_readers);
 265                                 }
 266                         }
 267                 }
 268         }
 269
 270         vnode_unlock(vp);
 271         return (0);
 272 bad:
 273         fifo_close_internal(vp, ap->a_mode, ap->a_context, 1);
 274
 275         vnode_unlock(vp);
 276         return (error);
 277 bad1:
 278         vnode_lock(vp);
 279
 280         fip->fi_flags &= ~FIFO_INCREATE;
 281
 282         if ((fip->fi_flags & FIFO_CREATEWAIT)) {
 283                 fip->fi_flags &= ~FIFO_CREATEWAIT;
 284                 wakeup(&fip->fi_flags);
 285         }
 286         vnode_unlock(vp);
 287
 288         return (error);
 289 }
 290
 291 /*
 292  * Vnode op for read
 293  */
 294 int
 295 fifo_read(struct vnop_read_args *ap)
 296 {
 297         struct uio *uio = ap->a_uio;
 298         struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
 299         user_ssize_t startresid;
 300         int error;
 301         int rflags;
 302
 303 #if DIAGNOSTIC
 304         if (uio->uio_rw != UIO_READ)
 305                 panic("fifo_read mode");
 306 #endif
 307         if (uio_resid(uio) == 0)
 308                 return (0);
 309
 310         rflags = (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0;
 311
 312         startresid = uio_resid(uio);
 313
 314         /* fifo conformance - if we have a reader open on the fifo but no
 315          * writers then we need to make sure we do not block.  We do that by
 316          * checking the receive buffer and if empty set error to EWOULDBLOCK.
 317          * If error is set to EWOULDBLOCK we skip the call into soreceive
 318          */
 319         error = 0;
 320         if (ap->a_vp->v_fifoinfo->fi_writers < 1) {
 321                 socket_lock(rso, 1);
 322                 error = (rso->so_rcv.sb_cc == 0) ? EWOULDBLOCK : 0;
 323                 socket_unlock(rso, 1);
 324         }
 325
 326         /* skip soreceive to avoid blocking when we have no writers */
 327         if (error != EWOULDBLOCK) {
 328                 error = soreceive(rso, (struct sockaddr **)0, uio, (struct mbuf **)0,
 329                                                 (struct mbuf **)0, &rflags);
 330                 if (error == 0)
 331                         lock_vnode_and_post(ap->a_vp, 0);
 332         }
 333         else {
 334                 /* clear EWOULDBLOCK and return EOF (zero) */
 335                 error = 0;
 336         }
 337         /*
 338          * Clear EOF indication after first such return.
 339          */
 340         if (uio_resid(uio) == startresid) {
 341                 socket_lock(rso, 1);
 342                 rso->so_state &= ~SS_CANTRCVMORE;
 343                 socket_unlock(rso, 1);
 344         }
 345         return (error);
 346 }
 347
 348 /*
 349  * Vnode op for write
 350  */
 351 int
 352 fifo_write(struct vnop_write_args *ap)
 353 {
 354         struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
 355         int error;
 356
 357 #if DIAGNOSTIC
 358         if (ap->a_uio->uio_rw != UIO_WRITE)
 359                 panic("fifo_write mode");
 360 #endif
 361         error = sosend(wso, (struct sockaddr *)0, ap->a_uio, NULL,
 362                        (struct mbuf *)0, (ap->a_ioflag & IO_NDELAY) ? MSG_NBIO : 0);
 363         if (error == 0)
 364                 lock_vnode_and_post(ap->a_vp, 0);
 365
 366         return (error);
 367 }
 368
 369 /*
 370  * Device ioctl operation.
 371  */
 372 int
 373 fifo_ioctl(struct vnop_ioctl_args *ap)
 374 {
 375         struct fileproc filetmp;
 376         struct fileglob filefg;
 377         int error;
 378
 379         if (ap->a_command == FIONBIO)
 380                 return (0);
 381         bzero(&filetmp, sizeof(struct fileproc));
 382         filetmp.f_fglob = &filefg;
 383         if (ap->a_fflag & FREAD) {
 384                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 385                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
 386                 if (error)
 387                         return (error);
 388         }
 389         if (ap->a_fflag & FWRITE) {
 390                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 391                 error = soo_ioctl(&filetmp, ap->a_command, ap->a_data, ap->a_context);
 392                 if (error)
 393                         return (error);
 394         }
 395         return (0);
 396 }
 397
 398 int
 399 fifo_select(struct vnop_select_args *ap)
 400 {
 401         struct fileproc filetmp;
 402         struct fileglob filefg;
 403         int ready;
 404
 405         bzero(&filetmp, sizeof(struct fileproc));
 406         filetmp.f_fglob = &filefg;
 407         if (ap->a_which & FREAD) {
 408                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
 409                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
 410                 if (ready)
 411                         return (ready);
 412         }
 413         if (ap->a_which & FWRITE) {
 414                 filetmp.f_fglob->fg_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
 415                 ready = soo_select(&filetmp, ap->a_which, ap->a_wql, ap->a_context);
 416                 if (ready)
 417                         return (ready);
 418         }
 419         return (0);
 420 }
 421
 422 int
 423 fifo_inactive(__unused struct vnop_inactive_args *ap)
 424 {
 425         return (0);
 426 }
 427
 428
 429 /*
 430  * Device close routine
 431  */
 432 int
 433 fifo_close(struct vnop_close_args *ap)
 434 {
 435         return fifo_close_internal(ap->a_vp, ap->a_fflag, ap->a_context, 0);
 436 }
 437
 438 int
 439 fifo_close_internal(vnode_t vp, int fflag, __unused vfs_context_t context, int locked)
 440 {
 441         struct fifoinfo *fip = vp->v_fifoinfo;
 442         int error1, error2;
 443         struct socket *rso;
 444         struct socket *wso;
 445
 446         if (!locked)
 447                 vnode_lock(vp);
 448
 449         if ((fip->fi_flags & FIFO_CREATED) == 0) {
 450                 if (!locked)
 451                         vnode_unlock(vp);
 452                 return(0);
 453
 454         }
 455
 456         if (fflag & FREAD) {
 457                 fip->fi_readers--;
 458                 if (fip->fi_readers == 0){
 459                         socket_lock(fip->fi_writesock, 1);
 460                         socantsendmore(fip->fi_writesock);
 461                         socket_unlock(fip->fi_writesock, 1);
 462                 }
 463         }
 464
 465         if (fflag & FWRITE) {
 466                 fip->fi_writers--;
 467                 if (fip->fi_writers == 0) {
 468                         socket_lock(fip->fi_readsock, 1);
 469                         socantrcvmore(fip->fi_readsock);
 470                         socket_unlock(fip->fi_readsock, 1);
 471                 }
 472         }
 473 #if 0
 474         if (vnode_isinuse_locked(vp, 0, 1)) {
 475                 if (!locked)
 476                         vnode_unlock(vp);
 477                 return (0);
 478         }
 479 #endif
 480
 481         if (fip->fi_writers || fip->fi_readers) {
 482                 if (!locked)
 483                         vnode_unlock(vp);
 484                 return (0);
 485         }
 486
 487         wso = fip->fi_writesock;
 488         rso = fip->fi_readsock;
 489         fip->fi_readsock = NULL;
 490         fip->fi_writesock = NULL;
 491         fip->fi_flags &= ~FIFO_CREATED;
 492         if (!locked)
 493                 vnode_unlock(vp);
 494         error1 = soclose(rso);
 495         error2 = soclose(wso);
 496
 497         if (error1)
 498                 return (error1);
 499         return (error2);
 500 }
 501
 502 /*
 503  * Print out internal contents of a fifo vnode.
 504  */
 505 void
 506 fifo_printinfo(struct vnode *vp)
 507 {
 508         struct fifoinfo *fip = vp->v_fifoinfo;
 509
 510         printf(", fifo with %ld readers and %ld writers",
 511                 fip->fi_readers, fip->fi_writers);
 512 }
 513
 514 /*
 515  * Return POSIX pathconf information applicable to fifo's.
 516  */
 517 int
 518 fifo_pathconf(struct vnop_pathconf_args *ap)
 519 {
 520         switch (ap->a_name) {
 521         case _PC_LINK_MAX:
 522                 *ap->a_retval = LINK_MAX;
 523                 return (0);
 524         case _PC_PIPE_BUF:
 525                 *ap->a_retval = PIPE_BUF;
 526                 return (0);
 527         case _PC_CHOWN_RESTRICTED:
 528                 *ap->a_retval = 200112;         /* _POSIX_CHOWN_RESTRICTED */
 529                 return (0);
 530         default:
 531                 return (EINVAL);
 532         }
 533         /* NOTREACHED */
 534 }
 535
 536 /*
 537  * Fifo failed operation
 538  */
 539 int
 540 fifo_ebadf(__unused void *dummy)
 541 {
 542
 543         return (EBADF);
 544 }
 545
 546 /*
 547  * Fifo advisory byte-level locks.
 548  */
 549 int
 550 fifo_advlock(__unused struct vnop_advlock_args *ap)
 551 {
 552
 553         return (ENOTSUP);
 554 }
 555
 556
 557 /* You'd certainly better have an iocount on the vnode! */
 558 int
 559 fifo_freespace(struct vnode *vp, long *count)
 560 {
 561         struct socket *rsock;
 562         rsock = vp->v_fifoinfo->fi_readsock;
 563         socket_lock(rsock, 1);
 564         *count = sbspace(&rsock->so_rcv);
 565         socket_unlock(rsock, 1);
 566         return 0;
 567 }
 568
 569 int
 570 fifo_charcount(struct vnode *vp, int *count)
 571 {
 572         int mcount;
 573         int err = sock_ioctl(vp->v_fifoinfo->fi_readsock, FIONREAD, (void*)&mcount);
 574         if (err == 0) {
 575                 *count = mcount;
 576         }
 577         return err;
 578 }