Module Name: src
Committed By: thorpej
Date: Sat Oct 2 02:07:42 UTC 2021
Modified Files:
src/sys/kern: uipc_socket2.c
src/sys/miscfs/fifofs: fifo_vnops.c
src/tests/lib/libc/sys: t_poll.c
Log Message:
- fifo_poll(): If the last writer has disappeared, detect this and return
POLLHUP, per POSIX.
- fifo_close(): Use the new fifo_socantrcvmore(), which is like the
garden-variety socantrcvmore(), except it specifies POLL_HUP rather
than POLL_IN (so the correct code for SIGIO is sent).
- sowakeup(): Allow POLL_HUP as a code (notifies poll'ers with POLLHUP).
- Add test cases for correct POLLHUP behavior with FIFOs.
Fixes PR kern/56429.
To generate a diff of this commit:
cvs rdiff -u -r1.139 -r1.140 src/sys/kern/uipc_socket2.c
cvs rdiff -u -r1.86 -r1.87 src/sys/miscfs/fifofs/fifo_vnops.c
cvs rdiff -u -r1.4 -r1.5 src/tests/lib/libc/sys/t_poll.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/uipc_socket2.c
diff -u src/sys/kern/uipc_socket2.c:1.139 src/sys/kern/uipc_socket2.c:1.140
--- src/sys/kern/uipc_socket2.c:1.139 Thu Mar 4 01:35:31 2021
+++ src/sys/kern/uipc_socket2.c Sat Oct 2 02:07:41 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: uipc_socket2.c,v 1.139 2021/03/04 01:35:31 msaitoh Exp $ */
+/* $NetBSD: uipc_socket2.c,v 1.140 2021/10/02 02:07:41 thorpej Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uipc_socket2.c,v 1.139 2021/03/04 01:35:31 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uipc_socket2.c,v 1.140 2021/10/02 02:07:41 thorpej Exp $");
#ifdef _KERNEL_OPT
#include "opt_ddb.h"
@@ -555,10 +555,27 @@ sowakeup(struct socket *so, struct sockb
KASSERT(solocked(so));
KASSERT(sb->sb_so == so);
- if (code == POLL_IN)
+ switch (code) {
+ case POLL_IN:
band = POLLIN|POLLRDNORM;
- else
+ break;
+
+ case POLL_OUT:
band = POLLOUT|POLLWRNORM;
+ break;
+
+ case POLL_HUP:
+ band = POLLHUP;
+ break;
+
+ default:
+ band = 0;
+#ifdef DIAGNOSTIC
+ printf("bad siginfo code %d in socket notification.\n", code);
+#endif
+ break;
+ }
+
sb->sb_flags &= ~SB_NOTIFY;
selnotify(&sb->sb_sel, band, NOTE_SUBMIT);
cv_broadcast(&sb->sb_cv);
Index: src/sys/miscfs/fifofs/fifo_vnops.c
diff -u src/sys/miscfs/fifofs/fifo_vnops.c:1.86 src/sys/miscfs/fifofs/fifo_vnops.c:1.87
--- src/sys/miscfs/fifofs/fifo_vnops.c:1.86 Wed Sep 29 13:15:45 2021
+++ src/sys/miscfs/fifofs/fifo_vnops.c Sat Oct 2 02:07:41 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: fifo_vnops.c,v 1.86 2021/09/29 13:15:45 thorpej Exp $ */
+/* $NetBSD: fifo_vnops.c,v 1.87 2021/10/02 02:07:41 thorpej Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -58,7 +58,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: fifo_vnops.c,v 1.86 2021/09/29 13:15:45 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: fifo_vnops.c,v 1.87 2021/10/02 02:07:41 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -337,24 +337,69 @@ fifo_poll(void *v)
struct vop_poll_args /* {
struct vnode *a_vp;
int a_events;
- struct lwp *a_l;
} */ *ap = v;
- struct socket *so;
- int revents;
+ struct socket *rso = ap->a_vp->v_fifoinfo->fi_readsock;
+ struct socket *wso = ap->a_vp->v_fifoinfo->fi_writesock;
+ struct socket *lso = NULL;
+ int events;
+
+ /*
+ * N.B. We're using a slightly different naming convention
+ * for these variables that most poll handlers.
+ */
+ int revents = 0;
+ int wevents = 0;
+
+ if (rso != NULL) {
+ lso = rso;
+ } else if (wso != NULL) {
+ lso = wso;
+ }
- revents = 0;
- if (ap->a_events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
- so = ap->a_vp->v_fifoinfo->fi_readsock;
- if (so)
- revents |= sopoll(so, ap->a_events);
+ if (lso == NULL) {
+ /* No associated sockets -> no events to report. */
+ return 0;
+ }
+
+ KASSERT(rso == NULL || lso->so_lock == rso->so_lock);
+ KASSERT(wso == NULL || lso->so_lock == wso->so_lock);
+
+ solock(lso);
+
+ if (rso != NULL) {
+ events = ap->a_events & (POLLIN | POLLRDNORM);
+ if (events != 0 && soreadable(rso)) {
+ revents |= events;
+ }
+ if (rso->so_state & SS_CANTRCVMORE) {
+ revents |= POLLHUP;
+ }
+ /*
+ * We always selrecord the read side here regardless
+ * of the caller's read interest because we need to
+ * action POLLHUP.
+ */
+ if (revents == 0) {
+ selrecord(curlwp, &rso->so_rcv.sb_sel);
+ rso->so_rcv.sb_flags |= SB_NOTIFY;
+ }
}
- if (ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND)) {
- so = ap->a_vp->v_fifoinfo->fi_writesock;
- if (so)
- revents |= sopoll(so, ap->a_events);
+
+ /* POSIX sez: POLLHUP and POLLOUT are mutually-exclusive. */
+ if (wso != NULL && (revents & POLLHUP) == 0) {
+ events = ap->a_events & (POLLOUT | POLLWRNORM);
+ if (events != 0 && sowritable(wso)) {
+ wevents |= events;
+ }
+ if (wevents == 0 && events != 0) {
+ selrecord(curlwp, &wso->so_snd.sb_sel);
+ wso->so_snd.sb_flags |= SB_NOTIFY;
+ }
}
- return (revents);
+ sounlock(lso);
+
+ return (revents | wevents);
}
static int
@@ -392,6 +437,20 @@ fifo_bmap(void *v)
}
/*
+ * This is like socantrcvmore(), but we send the POLL_HUP code.
+ */
+static void
+fifo_socantrcvmore(struct socket *so)
+{
+ KASSERT(solocked(so));
+
+ so->so_state |= SS_CANTRCVMORE;
+ if (sb_notify(&so->so_rcv)) {
+ sowakeup(so, &so->so_rcv, POLL_HUP);
+ }
+}
+
+/*
* Device close routine
*/
/* ARGSUSED */
@@ -422,13 +481,13 @@ fifo_close(void *v)
}
if (fip->fi_writers != 0) {
fip->fi_writers = 0;
- socantrcvmore(rso);
+ fifo_socantrcvmore(rso);
}
} else {
if ((ap->a_fflag & FREAD) && --fip->fi_readers == 0)
socantsendmore(wso);
if ((ap->a_fflag & FWRITE) && --fip->fi_writers == 0)
- socantrcvmore(rso);
+ fifo_socantrcvmore(rso);
}
if ((fip->fi_readers + fip->fi_writers) == 0) {
sounlock(wso);
Index: src/tests/lib/libc/sys/t_poll.c
diff -u src/tests/lib/libc/sys/t_poll.c:1.4 src/tests/lib/libc/sys/t_poll.c:1.5
--- src/tests/lib/libc/sys/t_poll.c:1.4 Fri Jul 17 15:34:16 2020
+++ src/tests/lib/libc/sys/t_poll.c Sat Oct 2 02:07:41 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: t_poll.c,v 1.4 2020/07/17 15:34:16 kamil Exp $ */
+/* $NetBSD: t_poll.c,v 1.5 2021/10/02 02:07:41 thorpej Exp $ */
/*-
* Copyright (c) 2011 The NetBSD Foundation, Inc.
@@ -29,6 +29,7 @@
* POSSIBILITY OF SUCH DAMAGE.
*/
+#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
@@ -233,6 +234,107 @@ ATF_TC_BODY(err, tc)
ATF_REQUIRE_ERRNO(EINVAL, poll(&pfd, 1, -2) == -1);
}
+static const char fifo_path[] = "pollhup_fifo";
+
+static void
+fifo_support(void)
+{
+ errno = 0;
+ if (mkfifo(fifo_path, 0600) == 0) {
+ ATF_REQUIRE(unlink(fifo_path) == 0);
+ return;
+ }
+
+ if (errno == EOPNOTSUPP) {
+ atf_tc_skip("the kernel does not support FIFOs");
+ } else {
+ atf_tc_fail("mkfifo(2) failed");
+ }
+}
+
+ATF_TC_WITH_CLEANUP(fifo_hup1);
+ATF_TC_HEAD(fifo_hup1, tc)
+{
+ atf_tc_set_md_var(tc, "descr",
+ "Check POLLHUP behavior with fifos [1]");
+}
+
+ATF_TC_BODY(fifo_hup1, tc)
+{
+ struct pollfd pfd;
+ int rfd, wfd;
+
+ fifo_support();
+
+ ATF_REQUIRE(mkfifo(fifo_path, 0600) == 0);
+ ATF_REQUIRE((rfd = open(fifo_path, O_RDONLY | O_NONBLOCK)) >= 0);
+ ATF_REQUIRE((wfd = open(fifo_path, O_WRONLY)) >= 0);
+
+ memset(&pfd, 0, sizeof(pfd));
+ pfd.fd = rfd;
+ pfd.events = POLLIN;
+
+ (void)close(wfd);
+
+ ATF_REQUIRE(poll(&pfd, 1, 0) == 1);
+ ATF_REQUIRE((pfd.revents & POLLHUP) != 0);
+}
+
+ATF_TC_CLEANUP(fifo_hup1, tc)
+{
+ (void)unlink(fifo_path);
+}
+
+ATF_TC_WITH_CLEANUP(fifo_hup2);
+ATF_TC_HEAD(fifo_hup2, tc)
+{
+ atf_tc_set_md_var(tc, "descr",
+ "Check POLLHUP behavior with fifos [2]");
+}
+
+ATF_TC_BODY(fifo_hup2, tc)
+{
+ struct pollfd pfd;
+ int rfd, wfd;
+ pid_t pid;
+ struct timespec ts1, ts2;
+
+ fifo_support();
+
+ ATF_REQUIRE(mkfifo(fifo_path, 0600) == 0);
+ ATF_REQUIRE((rfd = open(fifo_path, O_RDONLY | O_NONBLOCK)) >= 0);
+ ATF_REQUIRE((wfd = open(fifo_path, O_WRONLY)) >= 0);
+
+ memset(&pfd, 0, sizeof(pfd));
+ pfd.fd = rfd;
+ pfd.events = POLLIN;
+
+ pid = fork();
+ ATF_REQUIRE(pid >= 0);
+
+ if (pid == 0) {
+ (void)close(rfd);
+ sleep(5);
+ (void)close(wfd);
+ _exit(0);
+ }
+ (void)close(wfd);
+
+ ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &ts1) == 0);
+ ATF_REQUIRE(poll(&pfd, 1, INFTIM) == 1);
+ ATF_REQUIRE(clock_gettime(CLOCK_MONOTONIC, &ts2) == 0);
+
+ /* Make sure at least a couple of seconds have elapsed. */
+ ATF_REQUIRE(ts2.tv_sec - ts1.tv_sec >= 2);
+
+ ATF_REQUIRE((pfd.revents & POLLHUP) != 0);
+}
+
+ATF_TC_CLEANUP(fifo_hup2, tc)
+{
+ (void)unlink(fifo_path);
+}
+
ATF_TP_ADD_TCS(tp)
{
@@ -240,5 +342,8 @@ ATF_TP_ADD_TCS(tp)
ATF_TP_ADD_TC(tp, basic);
ATF_TP_ADD_TC(tp, err);
+ ATF_TP_ADD_TC(tp, fifo_hup1);
+ ATF_TP_ADD_TC(tp, fifo_hup2);
+
return atf_no_error();
}
