Date: Tue, 22 Jan 2002 01:50:01 -0800 (PST) From: Maxim Konovalov <maxim@macomnet.ru> To: freebsd-bugs@FreeBSD.org Subject: Re: kern/34020: poll(2) on fifos is broken Message-ID: <200201220950.g0M9o1F92222@freefall.freebsd.org>
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The following reply was made to PR kern/34020; it has been noted by GNATS.
From: Maxim Konovalov <maxim@macomnet.ru>
To: clemensF <ino-e31cbe40@spotteswoode.dnsalias.org>
Cc: FreeBSD-gnats-submit@FreeBSD.ORG
Subject: Re: kern/34020: poll(2) on fifos is broken
Date: Tue, 22 Jan 2002 12:42:01 +0300 (MSK)
Here you are.
Index: poll.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/poll.h,v
retrieving revision 1.6.2.1
diff -u -r1.6.2.1 poll.h
--- poll.h 2000/08/21 12:25:58 1.6.2.1
+++ poll.h 2002/01/22 09:37:31
@@ -70,6 +70,8 @@
#define POLLATTRIB 0x0400 /* file attributes may have changed */
#define POLLNLINK 0x0800 /* (un)link/rename may have happened */
#define POLLWRITE 0x1000 /* file's contents may have changed */
+/* General FreeBSD extensions (currently only supported for sockets): */
+#define POLLINIGNEOF 0x2000 /* POLLIN, except ignore EOF */
/*
* These events are set if they occur regardless of whether they were
Index: fifo_vnops.c
===================================================================
RCS file: /home/ncvs/src/sys/fs/fifofs/fifo_vnops.c,v
retrieving revision 1.45.2.2
diff -u -r1.45.2.2 fifo_vnops.c
--- fifo_vnops.c 2001/02/26 04:23:20 1.45.2.2
+++ fifo_vnops.c 2002/01/22 09:37:42
@@ -446,18 +446,41 @@
} */ *ap;
{
struct file filetmp;
- int revents = 0;
+ int events, revents = 0;
- if (ap->a_events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
+ events = ap->a_events &
+ (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM | POLLRDBAND);
+ if (events) {
+ /*
+ * Tell socket poll to ignore EOF so that we block if
+ * there is no writer (and no data).
+ */
+ if (events & (POLLIN | POLLRDNORM)) {
+ events &= ~(POLLIN | POLLRDNORM);
+ events |= POLLINIGNEOF;
+ }
filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_readsock;
if (filetmp.f_data)
- revents |= soo_poll(&filetmp, ap->a_events, ap->a_cred,
+ revents |= soo_poll(&filetmp, events, ap->a_cred,
ap->a_p);
+
+ /*
+ * If POLLIN or POLLRDNORM was requested and POLLINIGNEOF was
+ * not then convert POLLINIGNEOF back to POLLIN.
+ */
+ events = ap->a_events & (POLLIN | POLLRDNORM | POLLINIGNEOF);
+ if ((events & (POLLIN | POLLRDNORM)) &&
+ !(events & POLLINIGNEOF) &&
+ (revents & POLLINIGNEOF)) {
+ revents &= ~POLLINIGNEOF;
+ revents |= (events & (POLLIN | POLLRDNORM));
+ }
}
- if (ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
+ events = ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND);
+ if (events) {
filetmp.f_data = (caddr_t)ap->a_vp->v_fifoinfo->fi_writesock;
if (filetmp.f_data)
- revents |= soo_poll(&filetmp, ap->a_events, ap->a_cred,
+ revents |= soo_poll(&filetmp, events, ap->a_cred,
ap->a_p);
}
return (revents);
Index: uipc_socket.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/uipc_socket.c,v
retrieving revision 1.68.2.17
diff -u -r1.68.2.17 uipc_socket.c
--- uipc_socket.c 2001/12/01 21:32:42 1.68.2.17
+++ uipc_socket.c 2002/01/22 09:37:54
@@ -1518,6 +1518,11 @@
if (soreadable(so))
revents |= events & (POLLIN | POLLRDNORM);
+ if (events & POLLINIGNEOF)
+ if (so->so_rcv.sb_cc >= so->so_rcv.sb_lowat ||
+ !TAILQ_EMPTY(&so->so_comp) || so->so_error)
+ revents |= POLLINIGNEOF;
+
if (events & (POLLOUT | POLLWRNORM))
if (sowriteable(so))
revents |= events & (POLLOUT | POLLWRNORM);
@@ -1527,7 +1532,9 @@
revents |= events & (POLLPRI | POLLRDBAND);
if (revents == 0) {
- if (events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
+ if (events &
+ (POLLIN | POLLINIGNEOF | POLLPRI | POLLRDNORM |
+ POLLRDBAND)) {
selrecord(p, &so->so_rcv.sb_sel);
so->so_rcv.sb_flags |= SB_SEL;
}
--
Maxim Konovalov, MAcomnet, Internet-Intranet Dept., system engineer
phone: +7 (095) 796-9079, mailto: maxim@macomnet.ru
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