1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
22
23 /*
24 * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
25 */
26
27 /*
28 * The routines defined in this file are supporting routines for FIFOFS
29 * file system type.
30 */
31 #include <sys/types.h>
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/debug.h>
35 #include <sys/errno.h>
36 #include <sys/time.h>
37 #include <sys/kmem.h>
38 #include <sys/inline.h>
39 #include <sys/file.h>
40 #include <sys/proc.h>
41 #include <sys/stat.h>
42 #include <sys/sysmacros.h>
43 #include <sys/var.h>
44 #include <sys/vfs.h>
45 #include <sys/vfs_opreg.h>
46 #include <sys/vnode.h>
47 #include <sys/mode.h>
48 #include <sys/signal.h>
49 #include <sys/user.h>
50 #include <sys/uio.h>
51 #include <sys/flock.h>
52 #include <sys/stream.h>
53 #include <sys/fs/fifonode.h>
54 #include <sys/strsubr.h>
55 #include <sys/stropts.h>
56 #include <sys/cmn_err.h>
57 #include <fs/fs_subr.h>
58 #include <sys/ddi.h>
59
60
61 #if FIFODEBUG
62 int Fifo_fastmode = 1; /* pipes/fifos will be opened in fast mode */
63 int Fifo_verbose = 0; /* msg when switching out of fast mode */
64 int Fifohiwat = FIFOHIWAT; /* Modifiable FIFO high water mark */
65 #endif
66
67 /*
68 * This is the loadable module wrapper.
69 */
70 #include <sys/modctl.h>
71
72 extern struct qinit fifo_strdata;
73
74 struct vfsops *fifo_vfsops;
75
76 static vfsdef_t vfw = {
77 VFSDEF_VERSION,
78 "fifofs",
79 fifoinit,
80 VSW_ZMOUNT,
81 NULL
82 };
83
84 /*
85 * Module linkage information for the kernel.
86 */
87 extern struct mod_ops mod_fsops;
88
89 static struct modlfs modlfs = {
90 &mod_fsops, "filesystem for fifo", &vfw
91 };
92
93 static struct modlinkage modlinkage = {
94 MODREV_1, (void *)&modlfs, NULL
95 };
96
97 int
_init()98 _init()
99 {
100 return (mod_install(&modlinkage));
101 }
102
103 int
_info(struct modinfo * modinfop)104 _info(struct modinfo *modinfop)
105 {
106 return (mod_info(&modlinkage, modinfop));
107 }
108
109 /*
110 * Define data structures within this file.
111 * XXX should the hash size be configurable ?
112 */
113 #define FIFOSHFT 5
114 #define FIFO_HASHSZ 63
115
116 #if ((FIFO_HASHSZ & (FIFO_HASHSZ - 1)) == 0)
117 #define FIFOHASH(vp) (((uintptr_t)(vp) >> FIFOSHFT) & (FIFO_HASHSZ - 1))
118 #else
119 #define FIFOHASH(vp) (((uintptr_t)(vp) >> FIFOSHFT) % FIFO_HASHSZ)
120 #endif
121
122 fifonode_t *fifoalloc[FIFO_HASHSZ];
123 dev_t fifodev;
124 struct vfs *fifovfsp;
125 int fifofstype;
126
127 kmutex_t ftable_lock;
128 static kmutex_t fino_lock;
129 struct kmem_cache *fnode_cache;
130 struct kmem_cache *pipe_cache;
131
132 static void fifoinsert(fifonode_t *);
133 static fifonode_t *fifofind(vnode_t *);
134 static int fifo_connld(struct vnode **, int, cred_t *);
135 static void fifo_fastturnoff(fifonode_t *);
136
137 static void fifo_reinit_vp(vnode_t *);
138
139 static void fnode_destructor(void *, void *);
140
141 /*
142 * Constructor/destructor routines for fifos and pipes.
143 *
144 * In the interest of code sharing, we define a common fifodata structure
145 * which consists of a fifolock and one or two fnodes. A fifo contains
146 * one fnode; a pipe contains two. The fifolock is shared by the fnodes,
147 * each of which points to it:
148 *
149 * --> --> --------- --- ---
150 * | | | lock | | |
151 * | | --------- | |
152 * | | | | fifo |
153 * | --- | fnode | | |
154 * | | | | pipe
155 * | --------- --- |
156 * | | | |
157 * ------- | fnode | |
158 * | | |
159 * --------- ---
160 *
161 * Since the fifolock is at the beginning of the fifodata structure,
162 * the fifolock address is the same as the fifodata address. Thus,
163 * we can determine the fifodata address from any of its member fnodes.
164 * This is essential for fifo_inactive.
165 *
166 * The fnode constructor is designed to handle any fifodata structure,
167 * deducing the number of fnodes from the total size. Thus, the fnode
168 * constructor does most of the work for the pipe constructor.
169 */
170 static int
fnode_constructor(void * buf,void * cdrarg,int kmflags)171 fnode_constructor(void *buf, void *cdrarg, int kmflags)
172 {
173 fifodata_t *fdp = buf;
174 fifolock_t *flp = &fdp->fifo_lock;
175 fifonode_t *fnp = &fdp->fifo_fnode[0];
176 size_t size = (uintptr_t)cdrarg;
177
178 mutex_init(&flp->flk_lock, NULL, MUTEX_DEFAULT, NULL);
179 cv_init(&flp->flk_wait_cv, NULL, CV_DEFAULT, NULL);
180 flp->flk_ocsync = 0;
181
182 while ((char *)fnp < (char *)buf + size) {
183
184 vnode_t *vp;
185
186 vp = vn_alloc(kmflags);
187 if (vp == NULL) {
188 fnp->fn_vnode = NULL; /* mark for destructor */
189 fnode_destructor(buf, cdrarg);
190 return (-1);
191 }
192 fnp->fn_vnode = vp;
193
194 fnp->fn_lock = flp;
195 fnp->fn_open = 0;
196 fnp->fn_dest = fnp;
197 fnp->fn_mp = NULL;
198 fnp->fn_count = 0;
199 fnp->fn_rsynccnt = 0;
200 fnp->fn_wsynccnt = 0;
201 fnp->fn_wwaitcnt = 0;
202 fnp->fn_insync = 0;
203 fnp->fn_pcredp = NULL;
204 fnp->fn_cpid = -1;
205 /*
206 * 32-bit stat(2) may fail if fn_ino isn't initialized
207 */
208 fnp->fn_ino = 0;
209
210 cv_init(&fnp->fn_wait_cv, NULL, CV_DEFAULT, NULL);
211
212 vn_setops(vp, fifo_vnodeops);
213 vp->v_stream = NULL;
214 vp->v_type = VFIFO;
215 vp->v_data = (caddr_t)fnp;
216 vp->v_flag = VNOMAP | VNOSWAP;
217 vn_exists(vp);
218 fnp++;
219 }
220 return (0);
221 }
222
223 static void
fnode_destructor(void * buf,void * cdrarg)224 fnode_destructor(void *buf, void *cdrarg)
225 {
226 fifodata_t *fdp = buf;
227 fifolock_t *flp = &fdp->fifo_lock;
228 fifonode_t *fnp = &fdp->fifo_fnode[0];
229 size_t size = (uintptr_t)cdrarg;
230
231 mutex_destroy(&flp->flk_lock);
232 cv_destroy(&flp->flk_wait_cv);
233 ASSERT(flp->flk_ocsync == 0);
234
235 while ((char *)fnp < (char *)buf + size) {
236
237 vnode_t *vp = FTOV(fnp);
238
239 if (vp == NULL) {
240 return; /* constructor failed here */
241 }
242
243 ASSERT(fnp->fn_mp == NULL);
244 ASSERT(fnp->fn_count == 0);
245 ASSERT(fnp->fn_lock == flp);
246 ASSERT(fnp->fn_open == 0);
247 ASSERT(fnp->fn_insync == 0);
248 ASSERT(fnp->fn_rsynccnt == 0 && fnp->fn_wsynccnt == 0);
249 ASSERT(fnp->fn_wwaitcnt == 0);
250 ASSERT(fnp->fn_pcredp == NULL);
251 ASSERT(vn_matchops(vp, fifo_vnodeops));
252 ASSERT(vp->v_stream == NULL);
253 ASSERT(vp->v_type == VFIFO);
254 ASSERT(vp->v_data == (caddr_t)fnp);
255 ASSERT((vp->v_flag & (VNOMAP|VNOSWAP)) == (VNOMAP|VNOSWAP));
256
257 cv_destroy(&fnp->fn_wait_cv);
258 vn_invalid(vp);
259 vn_free(vp);
260
261 fnp++;
262 }
263 }
264
265 static int
pipe_constructor(void * buf,void * cdrarg,int kmflags)266 pipe_constructor(void *buf, void *cdrarg, int kmflags)
267 {
268 fifodata_t *fdp = buf;
269 fifonode_t *fnp1 = &fdp->fifo_fnode[0];
270 fifonode_t *fnp2 = &fdp->fifo_fnode[1];
271 vnode_t *vp1;
272 vnode_t *vp2;
273
274 (void) fnode_constructor(buf, cdrarg, kmflags);
275
276 vp1 = FTOV(fnp1);
277 vp2 = FTOV(fnp2);
278
279 vp1->v_vfsp = vp2->v_vfsp = fifovfsp;
280 vp1->v_rdev = vp2->v_rdev = fifodev;
281 fnp1->fn_realvp = fnp2->fn_realvp = NULL;
282 fnp1->fn_dest = fnp2;
283 fnp2->fn_dest = fnp1;
284
285 return (0);
286 }
287
288 static void
pipe_destructor(void * buf,void * cdrarg)289 pipe_destructor(void *buf, void *cdrarg)
290 {
291 #ifdef DEBUG
292 fifodata_t *fdp = buf;
293 fifonode_t *fnp1 = &fdp->fifo_fnode[0];
294 fifonode_t *fnp2 = &fdp->fifo_fnode[1];
295 vnode_t *vp1 = FTOV(fnp1);
296 vnode_t *vp2 = FTOV(fnp2);
297
298 ASSERT(vp1->v_vfsp == fifovfsp);
299 ASSERT(vp2->v_vfsp == fifovfsp);
300 ASSERT(vp1->v_rdev == fifodev);
301 ASSERT(vp2->v_rdev == fifodev);
302 #endif
303 fnode_destructor(buf, cdrarg);
304 }
305
306 /*
307 * Reinitialize a FIFO vnode (uses normal vnode reinit, but ensures that
308 * vnode type and flags are reset).
309 */
310
fifo_reinit_vp(vnode_t * vp)311 static void fifo_reinit_vp(vnode_t *vp)
312 {
313 vn_reinit(vp);
314 vp->v_type = VFIFO;
315 vp->v_flag &= VROOT;
316 vp->v_flag |= VNOMAP | VNOSWAP;
317 }
318
319 /*
320 * Save file system type/index, initialize vfs operations vector, get
321 * unique device number for FIFOFS and initialize the FIFOFS hash.
322 * Create and initialize a "generic" vfs pointer that will be placed
323 * in the v_vfsp field of each pipe's vnode.
324 */
325 int
fifoinit(int fstype,char * name)326 fifoinit(int fstype, char *name)
327 {
328 static const fs_operation_def_t fifo_vfsops_template[] = {
329 NULL, NULL
330 };
331 int error;
332 major_t dev;
333
334 fifofstype = fstype;
335 error = vfs_setfsops(fstype, fifo_vfsops_template, &fifo_vfsops);
336 if (error != 0) {
337 cmn_err(CE_WARN, "fifoinit: bad vfs ops template");
338 return (error);
339 }
340
341 error = vn_make_ops(name, fifo_vnodeops_template, &fifo_vnodeops);
342 if (error != 0) {
343 (void) vfs_freevfsops_by_type(fstype);
344 cmn_err(CE_WARN, "fifoinit: bad vnode ops template");
345 return (error);
346 }
347
348 if ((dev = getudev()) == (major_t)-1) {
349 cmn_err(CE_WARN, "fifoinit: can't get unique device number");
350 dev = 0;
351 }
352 fifodev = makedevice(dev, 0);
353
354 fifovfsp = kmem_zalloc(sizeof (struct vfs), KM_SLEEP);
355 fifovfsp->vfs_next = NULL;
356 vfs_setops(fifovfsp, fifo_vfsops);
357 fifovfsp->vfs_vnodecovered = NULL;
358 fifovfsp->vfs_flag = 0;
359 fifovfsp->vfs_bsize = 1024;
360 fifovfsp->vfs_fstype = fifofstype;
361 vfs_make_fsid(&fifovfsp->vfs_fsid, fifodev, fifofstype);
362 fifovfsp->vfs_data = NULL;
363 fifovfsp->vfs_dev = fifodev;
364 fifovfsp->vfs_bcount = 0;
365
366 /*
367 * It is necessary to initialize vfs_count here to 1.
368 * This prevents the fifovfsp from getting freed when
369 * a thread does a VFS_HOLD followed by a VFS_RELE
370 * on the fifovfsp
371 *
372 * The fifovfsp should never be freed.
373 */
374 fifovfsp->vfs_count = 1;
375
376 mutex_init(&ftable_lock, NULL, MUTEX_DEFAULT, NULL);
377 mutex_init(&fino_lock, NULL, MUTEX_DEFAULT, NULL);
378
379 /*
380 * vnodes are cached aligned
381 */
382 fnode_cache = kmem_cache_create("fnode_cache",
383 sizeof (fifodata_t) - sizeof (fifonode_t), 32,
384 fnode_constructor, fnode_destructor, NULL,
385 (void *)(sizeof (fifodata_t) - sizeof (fifonode_t)), NULL, 0);
386
387 pipe_cache = kmem_cache_create("pipe_cache", sizeof (fifodata_t), 32,
388 pipe_constructor, pipe_destructor, NULL,
389 (void *)(sizeof (fifodata_t)), NULL, 0);
390
391 #if FIFODEBUG
392 if (Fifohiwat < FIFOHIWAT)
393 Fifohiwat = FIFOHIWAT;
394 #endif /* FIFODEBUG */
395 fifo_strdata.qi_minfo->mi_hiwat = Fifohiwat;
396
397 return (0);
398 }
399
400 /*
401 * Provide a shadow for a vnode. We create a new shadow before checking for an
402 * existing one, to minimize the amount of time we need to hold ftable_lock.
403 * If a vp already has a shadow in the hash list, return its shadow. If not,
404 * we hash the new vnode and return its pointer to the caller.
405 */
406 vnode_t *
fifovp(vnode_t * vp,cred_t * crp)407 fifovp(vnode_t *vp, cred_t *crp)
408 {
409 fifonode_t *fnp;
410 fifonode_t *spec_fnp; /* Speculative fnode ptr. */
411 fifodata_t *fdp;
412 vnode_t *newvp;
413 struct vattr va;
414 vnode_t *rvp;
415
416 ASSERT(vp != NULL);
417
418 fdp = kmem_cache_alloc(fnode_cache, KM_SLEEP);
419
420 fdp->fifo_lock.flk_ref = 1;
421 fnp = &fdp->fifo_fnode[0];
422
423 /*
424 * Its possible that fifo nodes on different lofs mountpoints
425 * shadow the same real filesystem fifo node.
426 * In this case its necessary to get and store the realvp.
427 * This way different fifo nodes sharing the same real vnode
428 * can use realvp for communication.
429 */
430
431 if (VOP_REALVP(vp, &rvp, NULL) == 0)
432 vp = rvp;
433
434 fnp->fn_realvp = vp;
435 fnp->fn_wcnt = 0;
436 fnp->fn_rcnt = 0;
437
438 #if FIFODEBUG
439 if (! Fifo_fastmode) {
440 fnp->fn_flag = 0;
441 } else {
442 fnp->fn_flag = FIFOFAST;
443 }
444 #else /* FIFODEBUG */
445 fnp->fn_flag = FIFOFAST;
446 #endif /* FIFODEBUG */
447
448 /*
449 * initialize the times from vp.
450 */
451 va.va_mask = AT_TIMES;
452 if (VOP_GETATTR(vp, &va, 0, crp, NULL) == 0) {
453 fnp->fn_atime = va.va_atime.tv_sec;
454 fnp->fn_mtime = va.va_mtime.tv_sec;
455 fnp->fn_ctime = va.va_ctime.tv_sec;
456 } else {
457 fnp->fn_atime = 0;
458 fnp->fn_mtime = 0;
459 fnp->fn_ctime = 0;
460 }
461
462 /*
463 * Grab the VP here to avoid holding locks
464 * whilst trying to acquire others.
465 */
466
467 VN_HOLD(vp);
468
469 mutex_enter(&ftable_lock);
470
471 if ((spec_fnp = fifofind(vp)) != NULL) {
472 mutex_exit(&ftable_lock);
473
474 /*
475 * Release the vnode and free up our pre-prepared fnode.
476 * Zero the lock reference just to explicitly signal
477 * this is unused.
478 */
479 VN_RELE(vp);
480 fdp->fifo_lock.flk_ref = 0;
481 kmem_cache_free(fnode_cache, fdp);
482
483 return (FTOV(spec_fnp));
484 }
485
486 newvp = FTOV(fnp);
487 fifo_reinit_vp(newvp);
488 /*
489 * Since the fifo vnode's v_vfsp needs to point to the
490 * underlying filesystem's vfsp we need to bump up the
491 * underlying filesystem's vfs reference count.
492 * The count is decremented when the fifo node is
493 * inactivated.
494 */
495
496 VFS_HOLD(vp->v_vfsp);
497 newvp->v_vfsp = vp->v_vfsp;
498 newvp->v_rdev = vp->v_rdev;
499 newvp->v_flag |= (vp->v_flag & VROOT);
500
501 fifoinsert(fnp);
502 mutex_exit(&ftable_lock);
503
504 return (newvp);
505 }
506
507 /*
508 * Create a pipe end by...
509 * allocating a vnode-fifonode pair and initializing the fifonode.
510 */
511 void
makepipe(vnode_t ** vpp1,vnode_t ** vpp2)512 makepipe(vnode_t **vpp1, vnode_t **vpp2)
513 {
514 fifonode_t *fnp1;
515 fifonode_t *fnp2;
516 vnode_t *nvp1;
517 vnode_t *nvp2;
518 fifodata_t *fdp;
519 time_t now;
520
521 fdp = kmem_cache_alloc(pipe_cache, KM_SLEEP);
522 fdp->fifo_lock.flk_ref = 2;
523 fnp1 = &fdp->fifo_fnode[0];
524 fnp2 = &fdp->fifo_fnode[1];
525
526 fnp1->fn_wcnt = fnp2->fn_wcnt = 1;
527 fnp1->fn_rcnt = fnp2->fn_rcnt = 1;
528 #if FIFODEBUG
529 if (! Fifo_fastmode) {
530 fnp1->fn_flag = fnp2->fn_flag = ISPIPE;
531 } else {
532 fnp1->fn_flag = fnp2->fn_flag = ISPIPE | FIFOFAST;
533 }
534 #else /* FIFODEBUG */
535 fnp1->fn_flag = fnp2->fn_flag = ISPIPE | FIFOFAST;
536 #endif /* FIFODEBUG */
537 now = gethrestime_sec();
538 fnp1->fn_atime = fnp2->fn_atime = now;
539 fnp1->fn_mtime = fnp2->fn_mtime = now;
540 fnp1->fn_ctime = fnp2->fn_ctime = now;
541
542 *vpp1 = nvp1 = FTOV(fnp1);
543 *vpp2 = nvp2 = FTOV(fnp2);
544
545 fifo_reinit_vp(nvp1); /* Reinitialize vnodes for reuse... */
546 fifo_reinit_vp(nvp2);
547 nvp1->v_vfsp = fifovfsp; /* Need to re-establish VFS & device */
548 nvp2->v_vfsp = fifovfsp; /* before we can reuse this vnode. */
549 nvp1->v_rdev = fifodev;
550 nvp2->v_rdev = fifodev;
551 }
552
553 /*
554 * Attempt to establish a unique pipe id. Only un-named pipes use this
555 * routine.
556 */
557 ino_t
fifogetid(void)558 fifogetid(void)
559 {
560 static ino_t fifo_ino = 0;
561 ino_t fino;
562
563 mutex_enter(&fino_lock);
564 fino = fifo_ino++ & 0xffffffffull;
565 mutex_exit(&fino_lock);
566 return (fino);
567 }
568
569
570 /*
571 * Stream a pipe/FIFO.
572 * The FIFOCONNLD flag is used when CONNLD has been pushed on the stream.
573 * If the flag is set, a new vnode is created by calling fifo_connld().
574 * Connld logic was moved to fifo_connld() to speed up the open
575 * operation, simplify the connld/fifo interaction, and remove inherent
576 * race conditions between the connld module and fifos.
577 * This routine is single threaded for two reasons.
578 * 1) connld requests are synchronous; that is, they must block
579 * until the server does an I_RECVFD (oh, well). Single threading is
580 * the simplest way to accomplish this.
581 * 2) fifo_close() must not send M_HANGUP or M_ERROR while we are
582 * in stropen. Stropen() has a tendency to reset things and
583 * we would like streams to remember that a hangup occurred.
584 */
585 int
fifo_stropen(vnode_t ** vpp,int flag,cred_t * crp,int dotwist,int lockheld)586 fifo_stropen(vnode_t **vpp, int flag, cred_t *crp, int dotwist, int lockheld)
587 {
588 int error = 0;
589 vnode_t *oldvp = *vpp;
590 fifonode_t *fnp = VTOF(*vpp);
591 dev_t pdev = 0;
592 int firstopen = 0;
593 fifolock_t *fn_lock;
594
595 fn_lock = fnp->fn_lock;
596 if (!lockheld)
597 mutex_enter(&fn_lock->flk_lock);
598 ASSERT(MUTEX_HELD(&fnp->fn_lock->flk_lock));
599
600 /*
601 * FIFO is in the process of opening. Wait for it
602 * to complete before starting another open on it
603 * This prevents races associated with connld open
604 */
605 while (fnp->fn_flag & FIFOOPEN) {
606 if (!cv_wait_sig(&fnp->fn_wait_cv, &fn_lock->flk_lock)) {
607 fifo_cleanup(oldvp, flag);
608 if (!lockheld)
609 mutex_exit(&fn_lock->flk_lock);
610 return (EINTR);
611 }
612 }
613
614 /*
615 * The other end of the pipe is almost closed so
616 * reject any other open on this end of the pipe
617 * This only happens with a pipe mounted under namefs
618 */
619 if ((fnp->fn_flag & (FIFOCLOSE|ISPIPE)) == (FIFOCLOSE|ISPIPE)) {
620 fifo_cleanup(oldvp, flag);
621 cv_broadcast(&fnp->fn_wait_cv);
622 if (!lockheld)
623 mutex_exit(&fn_lock->flk_lock);
624 return (ENXIO);
625 }
626
627 fnp->fn_flag |= FIFOOPEN;
628
629 /*
630 * can't allow close to happen while we are
631 * in the middle of stropen().
632 * M_HANGUP and M_ERROR could leave the stream in a strange state
633 */
634 while (fn_lock->flk_ocsync)
635 cv_wait(&fn_lock->flk_wait_cv, &fn_lock->flk_lock);
636
637 fn_lock->flk_ocsync = 1;
638
639 if (fnp->fn_flag & FIFOCONNLD) {
640 /*
641 * This is a reopen, so we should release the fifo lock
642 * just in case some strange module pushed on connld
643 * has some odd side effect.
644 * Note: this stropen is on the oldvp. It will
645 * have no impact on the connld vp returned and
646 * strclose() will only be called when we release
647 * flk_ocsync
648 */
649 mutex_exit(&fn_lock->flk_lock);
650 if ((error = stropen(oldvp, &pdev, flag, crp)) != 0) {
651 mutex_enter(&fn_lock->flk_lock);
652 fifo_cleanup(oldvp, flag);
653 fn_lock->flk_ocsync = 0;
654 cv_broadcast(&fn_lock->flk_wait_cv);
655 goto out;
656 }
657 /*
658 * streams open done, allow close on other end if
659 * required. Do this now.. it could
660 * be a very long time before fifo_connld returns.
661 */
662 mutex_enter(&fn_lock->flk_lock);
663 /*
664 * we need to fake an open here so that if this
665 * end of the pipe closes, we don't loose the
666 * stream head (kind of like single threading
667 * open and close for this end of the pipe)
668 * We'll need to call fifo_close() to do clean
669 * up in case this end of the pipe was closed
670 * down while we were in fifo_connld()
671 */
672 ASSERT(fnp->fn_open > 0);
673 fnp->fn_open++;
674 fn_lock->flk_ocsync = 0;
675 cv_broadcast(&fn_lock->flk_wait_cv);
676 mutex_exit(&fn_lock->flk_lock);
677 /*
678 * Connld has been pushed onto the pipe
679 * Create new pipe on behalf of connld
680 */
681 if (error = fifo_connld(vpp, flag, crp)) {
682 (void) fifo_close(oldvp, flag, 1, 0, crp, NULL);
683 mutex_enter(&fn_lock->flk_lock);
684 goto out;
685 }
686 /*
687 * undo fake open. We need to call fifo_close
688 * because some other thread could have done
689 * a close and detach of the named pipe while
690 * we were in fifo_connld(), so
691 * we want to make sure the close completes (yuk)
692 */
693 (void) fifo_close(oldvp, flag, 1, 0, crp, NULL);
694 /*
695 * fifo_connld has changed the vp, so we
696 * need to re-initialize locals
697 */
698 fnp = VTOF(*vpp);
699 fn_lock = fnp->fn_lock;
700 mutex_enter(&fn_lock->flk_lock);
701 } else {
702 /*
703 * release lock in case there are modules pushed that
704 * could have some strange side effect
705 */
706
707 mutex_exit(&fn_lock->flk_lock);
708
709 /*
710 * If this is the first open of a fifo (dotwist
711 * will be non-zero) we will need to twist the queues.
712 */
713 if (oldvp->v_stream == NULL)
714 firstopen = 1;
715
716
717 /*
718 * normal open of pipe/fifo
719 */
720
721 if ((error = stropen(oldvp, &pdev, flag, crp)) != 0) {
722 mutex_enter(&fn_lock->flk_lock);
723 fifo_cleanup(oldvp, flag);
724 ASSERT(fnp->fn_open != 0 || oldvp->v_stream == NULL);
725 fn_lock->flk_ocsync = 0;
726 cv_broadcast(&fn_lock->flk_wait_cv);
727 goto out;
728 }
729 mutex_enter(&fn_lock->flk_lock);
730
731 /*
732 * twist the ends of the fifo together
733 */
734 if (dotwist && firstopen)
735 strmate(*vpp, *vpp);
736
737 /*
738 * Show that this open has succeeded
739 * and allow closes or other opens to proceed
740 */
741 fnp->fn_open++;
742 fn_lock->flk_ocsync = 0;
743 cv_broadcast(&fn_lock->flk_wait_cv);
744 }
745 out:
746 fnp->fn_flag &= ~FIFOOPEN;
747 if (error == 0) {
748 fnp->fn_flag |= FIFOISOPEN;
749 /*
750 * If this is a FIFO and has the close flag set
751 * and there are now writers, clear the close flag
752 * Note: close flag only gets set when last writer
753 * on a FIFO goes away.
754 */
755 if (((fnp->fn_flag & (ISPIPE|FIFOCLOSE)) == FIFOCLOSE) &&
756 fnp->fn_wcnt > 0)
757 fnp->fn_flag &= ~FIFOCLOSE;
758 }
759 cv_broadcast(&fnp->fn_wait_cv);
760 if (!lockheld)
761 mutex_exit(&fn_lock->flk_lock);
762 return (error);
763 }
764
765 /*
766 * Clean up the state of a FIFO and/or mounted pipe in the
767 * event that a fifo_open() was interrupted while the
768 * process was blocked.
769 */
770 void
fifo_cleanup(vnode_t * vp,int flag)771 fifo_cleanup(vnode_t *vp, int flag)
772 {
773 fifonode_t *fnp = VTOF(vp);
774
775 ASSERT(MUTEX_HELD(&fnp->fn_lock->flk_lock));
776
777 cleanlocks(vp, curproc->p_pid, 0);
778 cleanshares(vp, curproc->p_pid);
779 if (flag & FREAD) {
780 fnp->fn_rcnt--;
781 }
782 if (flag & FWRITE) {
783 fnp->fn_wcnt--;
784 }
785 cv_broadcast(&fnp->fn_wait_cv);
786 }
787
788
789 /*
790 * Insert a fifonode-vnode pair onto the fifoalloc hash list.
791 */
792 static void
fifoinsert(fifonode_t * fnp)793 fifoinsert(fifonode_t *fnp)
794 {
795 int idx = FIFOHASH(fnp->fn_realvp);
796
797 /*
798 * We don't need to hold fn_lock since we're holding ftable_lock and
799 * this routine is only called right after we've allocated an fnode.
800 * FIFO is inserted at head of NULL terminated doubly linked list.
801 */
802
803 ASSERT(MUTEX_HELD(&ftable_lock));
804 fnp->fn_backp = NULL;
805 fnp->fn_nextp = fifoalloc[idx];
806 fifoalloc[idx] = fnp;
807 if (fnp->fn_nextp)
808 fnp->fn_nextp->fn_backp = fnp;
809 }
810
811 /*
812 * Find a fifonode-vnode pair on the fifoalloc hash list.
813 * vp is a vnode to be shadowed. If it's on the hash list,
814 * it already has a shadow, therefore return its corresponding
815 * fifonode.
816 */
817 static fifonode_t *
fifofind(vnode_t * vp)818 fifofind(vnode_t *vp)
819 {
820 fifonode_t *fnode;
821
822 ASSERT(MUTEX_HELD(&ftable_lock));
823 for (fnode = fifoalloc[FIFOHASH(vp)]; fnode; fnode = fnode->fn_nextp) {
824 if (fnode->fn_realvp == vp) {
825 VN_HOLD(FTOV(fnode));
826 return (fnode);
827 }
828 }
829 return (NULL);
830 }
831
832 /*
833 * Remove a fifonode-vnode pair from the fifoalloc hash list.
834 * This routine is called from the fifo_inactive() routine when a
835 * FIFO is being released.
836 * If the link to be removed is the only link, set fifoalloc to NULL.
837 */
838 void
fiforemove(fifonode_t * fnp)839 fiforemove(fifonode_t *fnp)
840 {
841 int idx = FIFOHASH(fnp->fn_realvp);
842 fifonode_t *fnode;
843
844 ASSERT(MUTEX_HELD(&ftable_lock));
845 fnode = fifoalloc[idx];
846 /*
847 * fast path... only 1 FIFO in this list entry
848 */
849 if (fnode != NULL && fnode == fnp &&
850 !fnode->fn_nextp && !fnode->fn_backp) {
851 fifoalloc[idx] = NULL;
852 } else {
853
854 for (; fnode; fnode = fnode->fn_nextp) {
855 if (fnode == fnp) {
856 /*
857 * if we are first entry
858 */
859 if (fnp == fifoalloc[idx])
860 fifoalloc[idx] = fnp->fn_nextp;
861 if (fnode->fn_nextp)
862 fnode->fn_nextp->fn_backp =
863 fnode->fn_backp;
864 if (fnode->fn_backp)
865 fnode->fn_backp->fn_nextp =
866 fnode->fn_nextp;
867 break;
868 }
869 }
870 }
871 }
872
873 /*
874 * Flush all data from a fifo's message queue
875 */
876
877 void
fifo_fastflush(fifonode_t * fnp)878 fifo_fastflush(fifonode_t *fnp)
879 {
880 mblk_t *bp;
881 ASSERT(MUTEX_HELD(&fnp->fn_lock->flk_lock));
882
883 if ((bp = fnp->fn_mp) != NULL) {
884 fnp->fn_mp = NULL;
885 fnp->fn_count = 0;
886 freemsg(bp);
887 }
888 fifo_wakewriter(fnp->fn_dest, fnp->fn_lock);
889 }
890
891 /*
892 * Note: This routine is single threaded
893 * Protected by FIFOOPEN flag (i.e. flk_lock is not held)
894 * Upon successful completion, the original fifo is unlocked
895 * and FIFOOPEN is cleared for the original vpp.
896 * The new fifo returned has FIFOOPEN set.
897 */
898 static int
fifo_connld(struct vnode ** vpp,int flag,cred_t * crp)899 fifo_connld(struct vnode **vpp, int flag, cred_t *crp)
900 {
901 struct vnode *vp1;
902 struct vnode *vp2;
903 struct fifonode *oldfnp;
904 struct fifonode *fn_dest;
905 int error;
906 struct file *filep;
907 struct fifolock *fn_lock;
908 cred_t *c;
909
910 /*
911 * Get two vnodes that will represent the pipe ends for the new pipe.
912 */
913 makepipe(&vp1, &vp2);
914
915 /*
916 * Allocate a file descriptor and file pointer for one of the pipe
917 * ends. The file descriptor will be used to send that pipe end to
918 * the process on the other end of this stream. Note that we get
919 * the file structure only, there is no file list entry allocated.
920 */
921 if (error = falloc(vp1, FWRITE|FREAD, &filep, NULL)) {
922 VN_RELE(vp1);
923 VN_RELE(vp2);
924 return (error);
925 }
926 mutex_exit(&filep->f_tlock);
927 oldfnp = VTOF(*vpp);
928 fn_lock = oldfnp->fn_lock;
929 fn_dest = oldfnp->fn_dest;
930
931 /*
932 * Create two new stream heads and attach them to the two vnodes for
933 * the new pipe.
934 */
935 if ((error = fifo_stropen(&vp1, FREAD|FWRITE, filep->f_cred, 0, 0)) !=
936 0 ||
937 (error = fifo_stropen(&vp2, flag, filep->f_cred, 0, 0)) != 0) {
938 #if DEBUG
939 cmn_err(CE_NOTE, "fifo stropen failed error 0x%x", error);
940 #endif
941 /*
942 * this will call fifo_close and VN_RELE on vp1
943 */
944 (void) closef(filep);
945 VN_RELE(vp2);
946 return (error);
947 }
948
949 /*
950 * twist the ends of the pipe together
951 */
952 strmate(vp1, vp2);
953
954 /*
955 * Set our end to busy in open
956 * Note: Don't need lock around this because we're the only
957 * one who knows about it
958 */
959 VTOF(vp2)->fn_flag |= FIFOOPEN;
960
961 mutex_enter(&fn_lock->flk_lock);
962
963 fn_dest->fn_flag |= FIFOSEND;
964 /*
965 * check to make sure neither end of pipe has gone away
966 */
967 if (!(fn_dest->fn_flag & FIFOISOPEN)) {
968 error = ENXIO;
969 fn_dest->fn_flag &= ~FIFOSEND;
970 mutex_exit(&fn_lock->flk_lock);
971 /*
972 * this will call fifo_close and VN_RELE on vp1
973 */
974 goto out;
975 }
976 mutex_exit(&fn_lock->flk_lock);
977
978 /*
979 * Tag the sender's credential on the pipe descriptor.
980 */
981 crhold(VTOF(vp1)->fn_pcredp = crp);
982 VTOF(vp1)->fn_cpid = curproc->p_pid;
983
984 /*
985 * send the file descriptor to other end of pipe
986 */
987 if (error = do_sendfp((*vpp)->v_stream, filep, crp)) {
988 mutex_enter(&fn_lock->flk_lock);
989 fn_dest->fn_flag &= ~FIFOSEND;
990 mutex_exit(&fn_lock->flk_lock);
991 /*
992 * this will call fifo_close and VN_RELE on vp1
993 */
994 goto out;
995 }
996
997 mutex_enter(&fn_lock->flk_lock);
998 /*
999 * Wait for other end to receive file descriptor
1000 * FIFOCLOSE indicates that one or both sides of the pipe
1001 * have gone away.
1002 */
1003 while ((fn_dest->fn_flag & (FIFOCLOSE | FIFOSEND)) == FIFOSEND) {
1004 if (!cv_wait_sig(&oldfnp->fn_wait_cv, &fn_lock->flk_lock)) {
1005 error = EINTR;
1006 fn_dest->fn_flag &= ~FIFOSEND;
1007 mutex_exit(&fn_lock->flk_lock);
1008 goto out;
1009 }
1010 }
1011 /*
1012 * If either end of pipe has gone away and the other end did not
1013 * receive pipe, reject the connld open
1014 */
1015 if ((fn_dest->fn_flag & FIFOSEND)) {
1016 error = ENXIO;
1017 fn_dest->fn_flag &= ~FIFOSEND;
1018 mutex_exit(&fn_lock->flk_lock);
1019 goto out;
1020 }
1021
1022 oldfnp->fn_flag &= ~FIFOOPEN;
1023 cv_broadcast(&oldfnp->fn_wait_cv);
1024 mutex_exit(&fn_lock->flk_lock);
1025
1026 VN_RELE(*vpp);
1027 *vpp = vp2;
1028 (void) closef(filep);
1029 return (0);
1030 out:
1031 c = filep->f_cred;
1032 crhold(c);
1033 (void) closef(filep);
1034 VTOF(vp2)->fn_flag &= ~FIFOOPEN;
1035 (void) fifo_close(vp2, flag, 1, (offset_t)0, c, NULL);
1036 crfree(c);
1037 VN_RELE(vp2);
1038 return (error);
1039 }
1040
1041 /*
1042 * Disable fastpath mode.
1043 */
1044 void
fifo_fastoff(fifonode_t * fnp)1045 fifo_fastoff(fifonode_t *fnp)
1046 {
1047 ASSERT(MUTEX_HELD(&fnp->fn_lock->flk_lock));
1048 ASSERT(FTOV(fnp)->v_stream);
1049
1050 /* FIFOSTAYFAST is set => FIFOFAST is set */
1051 while ((fnp->fn_flag & FIFOSTAYFAST) || ((fnp->fn_flag & ISPIPE) &&
1052 (fnp->fn_dest->fn_flag & FIFOSTAYFAST))) {
1053 ASSERT(fnp->fn_flag & FIFOFAST);
1054 /* indicate someone is waiting to turn into stream mode */
1055 fnp->fn_flag |= FIFOWAITMODE;
1056 cv_wait(&fnp->fn_wait_cv, &fnp->fn_lock->flk_lock);
1057 fnp->fn_flag &= ~FIFOWAITMODE;
1058 }
1059
1060 /* as we may have relased the lock, test the FIFOFAST flag here */
1061 if (!(fnp->fn_flag & FIFOFAST))
1062 return;
1063 #if FIFODEBUG
1064 if (Fifo_verbose)
1065 cmn_err(CE_NOTE, "Fifo reverting to streams mode\n");
1066 #endif
1067
1068 fifo_fastturnoff(fnp);
1069 if (fnp->fn_flag & ISPIPE) {
1070 fifo_fastturnoff(fnp->fn_dest);
1071 }
1072 }
1073
1074
1075 /*
1076 * flk_lock must be held while calling fifo_fastturnoff() to
1077 * preserve data ordering (no reads or writes allowed)
1078 */
1079
1080 static void
fifo_fastturnoff(fifonode_t * fnp)1081 fifo_fastturnoff(fifonode_t *fnp)
1082 {
1083 fifonode_t *fn_dest = fnp->fn_dest;
1084 mblk_t *fn_mp;
1085 int fn_flag;
1086
1087 ASSERT(MUTEX_HELD(&fnp->fn_lock->flk_lock));
1088 /*
1089 * Note: This end can't be closed if there
1090 * is stuff in fn_mp
1091 */
1092 if ((fn_mp = fnp->fn_mp) != NULL) {
1093 ASSERT(fnp->fn_flag & FIFOISOPEN);
1094 ASSERT(FTOV(fnp)->v_stream != NULL);
1095 ASSERT(FTOV(fnp)->v_stream->sd_wrq != NULL);
1096 ASSERT(RD(FTOV(fnp)->v_stream->sd_wrq) != NULL);
1097 ASSERT(strvp2wq(FTOV(fnp)) != NULL);
1098 fnp->fn_mp = NULL;
1099 fnp->fn_count = 0;
1100 /*
1101 * Don't need to drop flk_lock across the put()
1102 * since we're just moving the message from the fifo
1103 * node to the STREAM head...
1104 */
1105 put(RD(strvp2wq(FTOV(fnp))), fn_mp);
1106 }
1107
1108 /*
1109 * Need to re-issue any pending poll requests
1110 * so that the STREAMS framework sees them
1111 * Writers would be waiting on fnp and readers on fn_dest
1112 */
1113 if ((fnp->fn_flag & (FIFOISOPEN | FIFOPOLLW)) ==
1114 (FIFOISOPEN | FIFOPOLLW)) {
1115 strpollwakeup(FTOV(fnp), POLLWRNORM);
1116 }
1117 fn_flag = fn_dest->fn_flag;
1118 if ((fn_flag & FIFOISOPEN) == FIFOISOPEN) {
1119 if ((fn_flag & (FIFOPOLLR | FIFOPOLLRBAND))) {
1120 strpollwakeup(FTOV(fn_dest), POLLIN|POLLRDNORM);
1121 }
1122 }
1123 /*
1124 * wake up any sleeping processes so they can notice we went
1125 * to streams mode
1126 */
1127 fnp->fn_flag &= ~(FIFOFAST|FIFOWANTW|FIFOWANTR);
1128 cv_broadcast(&fnp->fn_wait_cv);
1129 }
1130
1131 /*
1132 * Alternative version of fifo_fastoff()
1133 * optimized for putmsg/getmsg.
1134 */
1135 void
fifo_vfastoff(vnode_t * vp)1136 fifo_vfastoff(vnode_t *vp)
1137 {
1138 fifonode_t *fnp = VTOF(vp);
1139
1140 mutex_enter(&fnp->fn_lock->flk_lock);
1141 if (!(fnp->fn_flag & FIFOFAST)) {
1142 mutex_exit(&fnp->fn_lock->flk_lock);
1143 return;
1144 }
1145 fifo_fastoff(fnp);
1146 mutex_exit(&fnp->fn_lock->flk_lock);
1147 }
1148
1149 /*
1150 * Wake any sleeping writers, poll and send signals if necessary
1151 * This module is only called when we drop below the hi water mark
1152 * FIFOWANTW indicates that a process is sleeping in fifo_write()
1153 * FIFOHIWATW indicates that we have either attempted a poll or
1154 * non-blocking write and were over the high water mark
1155 * This routine assumes a low water mark of 0.
1156 */
1157
1158 void
fifo_wakewriter(fifonode_t * fn_dest,fifolock_t * fn_lock)1159 fifo_wakewriter(fifonode_t *fn_dest, fifolock_t *fn_lock)
1160 {
1161 int fn_dflag = fn_dest->fn_flag;
1162
1163 ASSERT(MUTEX_HELD(&fn_lock->flk_lock));
1164 ASSERT(fn_dest->fn_dest->fn_count < Fifohiwat);
1165 if ((fn_dflag & FIFOWANTW)) {
1166 cv_broadcast(&fn_dest->fn_wait_cv);
1167 }
1168 if ((fn_dflag & (FIFOHIWATW | FIFOISOPEN)) ==
1169 (FIFOHIWATW | FIFOISOPEN)) {
1170 if (fn_dflag & FIFOPOLLW)
1171 strpollwakeup(FTOV(fn_dest), POLLWRNORM);
1172 if (fn_dflag & FIFOSETSIG)
1173 str_sendsig(FTOV(fn_dest), S_WRNORM, 0, 0);
1174 }
1175 /*
1176 * FIFOPOLLW can't be set without setting FIFOHIWAT
1177 * This allows us to clear both here.
1178 */
1179 fn_dest->fn_flag = fn_dflag & ~(FIFOWANTW | FIFOHIWATW | FIFOPOLLW);
1180 }
1181
1182 /*
1183 * wake up any sleeping readers, poll or send signal if needed
1184 * FIFOWANTR indicates that a process is waiting in fifo_read() for data
1185 * FIFOSETSIG indicates that SIGPOLL should be sent to process
1186 * FIFOPOLLR indicates that a poll request for reading on the fifo was made
1187 */
1188
1189 void
fifo_wakereader(fifonode_t * fn_dest,fifolock_t * fn_lock)1190 fifo_wakereader(fifonode_t *fn_dest, fifolock_t *fn_lock)
1191 {
1192 int fn_dflag = fn_dest->fn_flag;
1193
1194 ASSERT(MUTEX_HELD(&fn_lock->flk_lock));
1195 if (fn_dflag & FIFOWANTR) {
1196 cv_broadcast(&fn_dest->fn_wait_cv);
1197 }
1198 if (fn_dflag & FIFOISOPEN) {
1199 if (fn_dflag & FIFOPOLLR)
1200 strpollwakeup(FTOV(fn_dest), POLLIN | POLLRDNORM);
1201 if (fn_dflag & FIFOSETSIG)
1202 str_sendsig(FTOV(fn_dest), S_INPUT | S_RDNORM, 0, 0);
1203 }
1204 fn_dest->fn_flag = fn_dflag & ~(FIFOWANTR | FIFOPOLLR);
1205 }
1206