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Allow a pipe to be opened read/write at one end, as is allowed in

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SunOS and SCO.  You can then even use the pipe as a cheap fifo stack
(yuck!).  A semantic change also important (but not limited) to iBCS2
compatibility.
Submitted by:	swallace
This commit is contained in:
Jordan K. Hubbard 1995-08-06 16:14:21 +00:00
parent 59eab48836
commit 78f1a844fb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=9973
2 changed files with 56 additions and 30 deletions
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43
sys/fs/fifofs/fifo_vnops.c
View File

@ -149,8 +149,6 @@ fifo_open(ap)
int error;
static char openstr[] = "fifo";
if ((ap->a_mode & (FREAD|FWRITE)) == (FREAD|FWRITE))
return (EINVAL);
if ((fip = vp->v_fifoinfo) == NULL) {
MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
vp->v_fifoinfo = fip;
@ -182,24 +180,38 @@ fifo_open(ap)
rso->so_state |= SS_CANTSENDMORE;
}
error = 0;
if (ap->a_mode & FREAD) {
if ((ap->a_mode & (FREAD|FWRITE)) == (FREAD|FWRITE)) {
if (fip->fi_readers == 0) {
fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
if (fip->fi_writers > 0)
wakeup((caddr_t)&fip->fi_writers);
}
if (fip->fi_writers == 0) {
fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
if (fip->fi_readers > 0)
wakeup((caddr_t)&fip->fi_readers);
}
fip->fi_readers++;
fip->fi_writers++;
}
else if (ap->a_mode & FREAD) {
fip->fi_readers++;
if (fip->fi_readers == 1) {
fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
if (fip->fi_writers > 0)
wakeup((caddr_t)&fip->fi_writers);
}
if (ap->a_mode & O_NONBLOCK)
return (0);
while (fip->fi_writers == 0) {
VOP_UNLOCK(vp);
error = tsleep((caddr_t)&fip->fi_readers,
PCATCH | PSOCK, openstr, 0);
VOP_LOCK(vp);
if (error)
break;
}
} else {
if (!(ap->a_mode & O_NONBLOCK))
while (fip->fi_writers == 0) {
VOP_UNLOCK(vp);
error = tsleep((caddr_t)&fip->fi_readers,
PCATCH | PSOCK, openstr, 0);
VOP_LOCK(vp);
if (error)
break;
}
}
else {
fip->fi_writers++;
if (fip->fi_readers == 0 && (ap->a_mode & O_NONBLOCK)) {
error = ENXIO;
@ -408,7 +420,8 @@ fifo_close(ap)
fip->fi_writers--;
if (fip->fi_writers == 0)
socantrcvmore(fip->fi_readsock);
} else {
}
if (ap->a_fflag & FREAD) {
fip->fi_readers--;
if (fip->fi_readers == 0)
socantsendmore(fip->fi_writesock);

43
sys/miscfs/fifofs/fifo_vnops.c
View File

@ -149,8 +149,6 @@ fifo_open(ap)
int error;
static char openstr[] = "fifo";
if ((ap->a_mode & (FREAD|FWRITE)) == (FREAD|FWRITE))
return (EINVAL);
if ((fip = vp->v_fifoinfo) == NULL) {
MALLOC(fip, struct fifoinfo *, sizeof(*fip), M_VNODE, M_WAITOK);
vp->v_fifoinfo = fip;
@ -182,24 +180,38 @@ fifo_open(ap)
rso->so_state |= SS_CANTSENDMORE;
}
error = 0;
if (ap->a_mode & FREAD) {
if ((ap->a_mode & (FREAD|FWRITE)) == (FREAD|FWRITE)) {
if (fip->fi_readers == 0) {
fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
if (fip->fi_writers > 0)
wakeup((caddr_t)&fip->fi_writers);
}
if (fip->fi_writers == 0) {
fip->fi_readsock->so_state &= ~SS_CANTRCVMORE;
if (fip->fi_readers > 0)
wakeup((caddr_t)&fip->fi_readers);
}
fip->fi_readers++;
fip->fi_writers++;
}
else if (ap->a_mode & FREAD) {
fip->fi_readers++;
if (fip->fi_readers == 1) {
fip->fi_writesock->so_state &= ~SS_CANTSENDMORE;
if (fip->fi_writers > 0)
wakeup((caddr_t)&fip->fi_writers);
}
if (ap->a_mode & O_NONBLOCK)
return (0);
while (fip->fi_writers == 0) {
VOP_UNLOCK(vp);
error = tsleep((caddr_t)&fip->fi_readers,
PCATCH | PSOCK, openstr, 0);
VOP_LOCK(vp);
if (error)
break;
}
} else {
if (!(ap->a_mode & O_NONBLOCK))
while (fip->fi_writers == 0) {
VOP_UNLOCK(vp);
error = tsleep((caddr_t)&fip->fi_readers,
PCATCH | PSOCK, openstr, 0);
VOP_LOCK(vp);
if (error)
break;
}
}
else {
fip->fi_writers++;
if (fip->fi_readers == 0 && (ap->a_mode & O_NONBLOCK)) {
error = ENXIO;
@ -408,7 +420,8 @@ fifo_close(ap)
fip->fi_writers--;
if (fip->fi_writers == 0)
socantrcvmore(fip->fi_readsock);
} else {
}
if (ap->a_fflag & FREAD) {
fip->fi_readers--;
if (fip->fi_readers == 0)
socantsendmore(fip->fi_writesock);