2 * Copyright (c) 1990, 1993, 1995
3 * The Regents of the University of California.
4 * Copyright (c) 2005 Robert N. M. Watson
5 * Copyright (c) 2012 Giovanni Trematerra
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9 * modification, are permitted provided that the following conditions
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32 * @(#)fifo_vnops.c 8.10 (Berkeley) 5/27/95
36 #include <sys/param.h>
37 #include <sys/event.h>
39 #include <sys/filedesc.h>
40 #include <sys/filio.h>
41 #include <sys/fcntl.h>
42 #include <sys/kernel.h>
44 #include <sys/mutex.h>
45 #include <sys/malloc.h>
46 #include <sys/selinfo.h>
49 #include <sys/signalvar.h>
51 #include <sys/systm.h>
53 #include <sys/unistd.h>
54 #include <sys/vnode.h>
57 * This structure is associated with the FIFO vnode and stores
58 * the state associated with the FIFO.
59 * Notes about locking:
60 * - fi_pipe is invariant since init time.
61 * - fi_readers and fi_writers are protected by the vnode lock.
71 static vop_print_t fifo_print;
72 static vop_open_t fifo_open;
73 static vop_close_t fifo_close;
74 static vop_advlock_t fifo_advlock;
76 struct vop_vector fifo_specops = {
77 .vop_default = &default_vnodeops,
79 .vop_advlock = fifo_advlock,
80 .vop_close = fifo_close,
81 .vop_create = VOP_PANIC,
82 .vop_getattr = VOP_EBADF,
83 .vop_ioctl = VOP_PANIC,
84 .vop_kqfilter = VOP_PANIC,
85 .vop_link = VOP_PANIC,
86 .vop_mkdir = VOP_PANIC,
87 .vop_mknod = VOP_PANIC,
88 .vop_open = fifo_open,
89 .vop_pathconf = vop_stdpathconf,
90 .vop_print = fifo_print,
91 .vop_read = VOP_PANIC,
92 .vop_readdir = VOP_PANIC,
93 .vop_readlink = VOP_PANIC,
94 .vop_reallocblks = VOP_PANIC,
95 .vop_reclaim = VOP_NULL,
96 .vop_remove = VOP_PANIC,
97 .vop_rename = VOP_PANIC,
98 .vop_rmdir = VOP_PANIC,
99 .vop_setattr = VOP_EBADF,
100 .vop_symlink = VOP_PANIC,
101 .vop_write = VOP_PANIC,
105 * Dispose of fifo resources.
108 fifo_cleanup(struct vnode *vp)
110 struct fifoinfo *fip;
112 ASSERT_VOP_ELOCKED(vp, "fifo_cleanup");
113 fip = vp->v_fifoinfo;
114 if (fip->fi_readers == 0 && fip->fi_writers == 0) {
115 vp->v_fifoinfo = NULL;
116 pipe_dtor(fip->fi_pipe);
122 * Open called to set up a new instance of a fifo or
123 * to find an active instance of a fifo.
128 struct vop_open_args /* {
131 struct ucred *a_cred;
139 struct fifoinfo *fip;
142 int error, stops_deferred;
147 ASSERT_VOP_ELOCKED(vp, "fifo_open");
148 if (fp == NULL || (ap->a_mode & FEXEC) != 0)
150 if ((fip = vp->v_fifoinfo) == NULL) {
151 pipe_named_ctor(&fpipe, td);
152 fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
153 fip->fi_pipe = fpipe;
154 fpipe->pipe_wgen = fip->fi_readers = fip->fi_writers = 0;
155 KASSERT(vp->v_fifoinfo == NULL, ("fifo_open: v_fifoinfo race"));
156 vp->v_fifoinfo = fip;
158 fpipe = fip->fi_pipe;
159 KASSERT(fpipe != NULL, ("fifo_open: pipe is NULL"));
162 * Use the pipe mutex here, in addition to the vnode lock,
163 * in order to allow vnode lock dropping before msleep() calls
164 * and still avoiding missed wakeups.
167 if (ap->a_mode & FREAD) {
170 if (fip->fi_readers == 1) {
171 fpipe->pipe_state &= ~PIPE_EOF;
172 if (fip->fi_writers > 0)
173 wakeup(&fip->fi_writers);
175 fp->f_seqcount = fpipe->pipe_wgen - fip->fi_writers;
177 if (ap->a_mode & FWRITE) {
178 if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
180 if (fip->fi_writers == 0)
186 if (fip->fi_writers == 1) {
187 fpipe->pipe_state &= ~PIPE_EOF;
188 if (fip->fi_readers > 0)
189 wakeup(&fip->fi_readers);
192 if ((ap->a_mode & O_NONBLOCK) == 0) {
193 if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
196 stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
197 error = msleep(&fip->fi_readers, PIPE_MTX(fpipe),
198 PDROP | PCATCH | PSOCK, "fifoor", 0);
199 sigallowstop(stops_deferred);
200 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
201 if (error != 0 && gen == fip->fi_wgen) {
203 if (fip->fi_readers == 0) {
205 fpipe->pipe_state |= PIPE_EOF;
206 if (fpipe->pipe_state & PIPE_WANTW)
215 * We must have got woken up because we had a writer.
216 * That (and not still having one) is the condition
217 * that we must wait for.
220 if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
223 stops_deferred = sigdeferstop(SIGDEFERSTOP_OFF);
224 error = msleep(&fip->fi_writers, PIPE_MTX(fpipe),
225 PDROP | PCATCH | PSOCK, "fifoow", 0);
226 sigallowstop(stops_deferred);
227 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
228 if (error != 0 && gen == fip->fi_rgen) {
230 if (fip->fi_writers == 0) {
232 fpipe->pipe_state |= PIPE_EOF;
233 if (fpipe->pipe_state & PIPE_WANTR)
242 * We must have got woken up because we had
243 * a reader. That (and not still having one)
244 * is the condition that we must wait for.
250 KASSERT(fp != NULL, ("can't fifo/vnode bypass"));
251 KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
252 finit(fp, fp->f_flag, DTYPE_FIFO, fpipe, &pipeops);
257 * Device close routine
262 struct vop_close_args /* {
265 struct ucred *a_cred;
270 struct fifoinfo *fip;
274 fip = vp->v_fifoinfo;
275 cpipe = fip->fi_pipe;
276 ASSERT_VOP_ELOCKED(vp, "fifo_close");
277 if (ap->a_fflag & FREAD) {
279 if (fip->fi_readers == 0) {
281 cpipe->pipe_state |= PIPE_EOF;
282 if ((cpipe->pipe_state & PIPE_WANTW)) {
283 cpipe->pipe_state &= ~PIPE_WANTW;
286 pipeselwakeup(cpipe);
290 if (ap->a_fflag & FWRITE) {
292 if (fip->fi_writers == 0) {
294 cpipe->pipe_state |= PIPE_EOF;
295 if ((cpipe->pipe_state & PIPE_WANTR)) {
296 cpipe->pipe_state &= ~PIPE_WANTR;
300 pipeselwakeup(cpipe);
309 * Print out internal contents of a fifo vnode.
315 struct fifoinfo *fip = vp->v_fifoinfo;
318 printf(", NULL v_fifoinfo");
321 printf(", fifo with %ld readers and %ld writers",
322 fip->fi_readers, fip->fi_writers);
327 * Print out the contents of a fifo vnode.
331 struct vop_print_args /* {
336 fifo_printinfo(ap->a_vp);
342 * Fifo advisory byte-level locks.
347 struct vop_advlock_args /* {
356 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);