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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12 * notice, this list of conditions and the following disclaimer.
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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_pathconf_t fifo_pathconf;
75 static vop_advlock_t fifo_advlock;
77 struct vop_vector fifo_specops = {
78 .vop_default = &default_vnodeops,
80 .vop_advlock = fifo_advlock,
81 .vop_close = fifo_close,
82 .vop_create = VOP_PANIC,
83 .vop_getattr = VOP_EBADF,
84 .vop_ioctl = VOP_PANIC,
85 .vop_kqfilter = VOP_PANIC,
86 .vop_link = VOP_PANIC,
87 .vop_mkdir = VOP_PANIC,
88 .vop_mknod = VOP_PANIC,
89 .vop_open = fifo_open,
90 .vop_pathconf = fifo_pathconf,
91 .vop_print = fifo_print,
92 .vop_read = VOP_PANIC,
93 .vop_readdir = VOP_PANIC,
94 .vop_readlink = VOP_PANIC,
95 .vop_reallocblks = VOP_PANIC,
96 .vop_reclaim = VOP_NULL,
97 .vop_remove = VOP_PANIC,
98 .vop_rename = VOP_PANIC,
99 .vop_rmdir = VOP_PANIC,
100 .vop_setattr = VOP_EBADF,
101 .vop_symlink = VOP_PANIC,
102 .vop_write = VOP_PANIC,
106 * Dispose of fifo resources.
109 fifo_cleanup(struct vnode *vp)
111 struct fifoinfo *fip;
113 ASSERT_VOP_ELOCKED(vp, "fifo_cleanup");
114 fip = vp->v_fifoinfo;
115 if (fip->fi_readers == 0 && fip->fi_writers == 0) {
116 vp->v_fifoinfo = NULL;
117 pipe_dtor(fip->fi_pipe);
123 * Open called to set up a new instance of a fifo or
124 * to find an active instance of a fifo.
129 struct vop_open_args /* {
132 struct ucred *a_cred;
140 struct fifoinfo *fip;
143 int error, stops_deferred;
148 ASSERT_VOP_ELOCKED(vp, "fifo_open");
149 if (fp == NULL || (ap->a_mode & FEXEC) != 0)
151 if ((fip = vp->v_fifoinfo) == NULL) {
152 pipe_named_ctor(&fpipe, td);
153 fip = malloc(sizeof(*fip), M_VNODE, M_WAITOK);
154 fip->fi_pipe = fpipe;
155 fpipe->pipe_wgen = fip->fi_readers = fip->fi_writers = 0;
156 KASSERT(vp->v_fifoinfo == NULL, ("fifo_open: v_fifoinfo race"));
157 vp->v_fifoinfo = fip;
159 fpipe = fip->fi_pipe;
160 KASSERT(fpipe != NULL, ("fifo_open: pipe is NULL"));
163 * Use the pipe mutex here, in addition to the vnode lock,
164 * in order to allow vnode lock dropping before msleep() calls
165 * and still avoiding missed wakeups.
168 if (ap->a_mode & FREAD) {
171 if (fip->fi_readers == 1) {
172 fpipe->pipe_state &= ~PIPE_EOF;
173 if (fip->fi_writers > 0)
174 wakeup(&fip->fi_writers);
176 fp->f_seqcount = fpipe->pipe_wgen - fip->fi_writers;
178 if (ap->a_mode & FWRITE) {
179 if ((ap->a_mode & O_NONBLOCK) && fip->fi_readers == 0) {
181 if (fip->fi_writers == 0)
187 if (fip->fi_writers == 1) {
188 fpipe->pipe_state &= ~PIPE_EOF;
189 if (fip->fi_readers > 0)
190 wakeup(&fip->fi_readers);
193 if ((ap->a_mode & O_NONBLOCK) == 0) {
194 if ((ap->a_mode & FREAD) && fip->fi_writers == 0) {
197 stops_deferred = sigallowstop();
198 error = msleep(&fip->fi_readers, PIPE_MTX(fpipe),
199 PDROP | PCATCH | PSOCK, "fifoor", 0);
202 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
203 if (error != 0 && gen == fip->fi_wgen) {
205 if (fip->fi_readers == 0) {
207 fpipe->pipe_state |= PIPE_EOF;
208 if (fpipe->pipe_state & PIPE_WANTW)
217 * We must have got woken up because we had a writer.
218 * That (and not still having one) is the condition
219 * that we must wait for.
222 if ((ap->a_mode & FWRITE) && fip->fi_readers == 0) {
225 stops_deferred = sigallowstop();
226 error = msleep(&fip->fi_writers, PIPE_MTX(fpipe),
227 PDROP | PCATCH | PSOCK, "fifoow", 0);
230 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
231 if (error != 0 && gen == fip->fi_rgen) {
233 if (fip->fi_writers == 0) {
235 fpipe->pipe_state |= PIPE_EOF;
236 if (fpipe->pipe_state & PIPE_WANTR)
245 * We must have got woken up because we had
246 * a reader. That (and not still having one)
247 * is the condition that we must wait for.
253 KASSERT(fp != NULL, ("can't fifo/vnode bypass"));
254 KASSERT(fp->f_ops == &badfileops, ("not badfileops in fifo_open"));
255 finit(fp, fp->f_flag, DTYPE_FIFO, fpipe, &pipeops);
260 * Device close routine
265 struct vop_close_args /* {
268 struct ucred *a_cred;
273 struct fifoinfo *fip;
277 fip = vp->v_fifoinfo;
278 cpipe = fip->fi_pipe;
279 ASSERT_VOP_ELOCKED(vp, "fifo_close");
280 if (ap->a_fflag & FREAD) {
282 if (fip->fi_readers == 0) {
284 cpipe->pipe_state |= PIPE_EOF;
285 if ((cpipe->pipe_state & PIPE_WANTW)) {
286 cpipe->pipe_state &= ~PIPE_WANTW;
289 pipeselwakeup(cpipe);
293 if (ap->a_fflag & FWRITE) {
295 if (fip->fi_writers == 0) {
297 cpipe->pipe_state |= PIPE_EOF;
298 if ((cpipe->pipe_state & PIPE_WANTR)) {
299 cpipe->pipe_state &= ~PIPE_WANTR;
303 pipeselwakeup(cpipe);
312 * Print out internal contents of a fifo vnode.
318 register struct fifoinfo *fip = vp->v_fifoinfo;
321 printf(", NULL v_fifoinfo");
324 printf(", fifo with %ld readers and %ld writers",
325 fip->fi_readers, fip->fi_writers);
330 * Print out the contents of a fifo vnode.
334 struct vop_print_args /* {
339 fifo_printinfo(ap->a_vp);
345 * Return POSIX pathconf information applicable to fifo's.
349 struct vop_pathconf_args /* {
356 switch (ap->a_name) {
358 *ap->a_retval = LINK_MAX;
361 *ap->a_retval = PIPE_BUF;
363 case _PC_CHOWN_RESTRICTED:
373 * Fifo advisory byte-level locks.
378 struct vop_advlock_args /* {
387 return (ap->a_flags & F_FLOCK ? EOPNOTSUPP : EINVAL);