git: 5fac6f16877f - stable/13 - poll(2): Add POLLRDHUP.
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Date: Fri, 17 Jun 2022 19:24:00 UTC
The branch stable/13 has been updated by dchagin:
URL: https://cgit.FreeBSD.org/src/commit/?id=5fac6f16877f6c0c5bb9de706b552fd405006690
commit 5fac6f16877f6c0c5bb9de706b552fd405006690
Author: Thomas Munro <tmunro@FreeBSD.org>
AuthorDate: 2021-04-28 09:31:38 +0000
Commit: Dmitry Chagin <dchagin@FreeBSD.org>
CommitDate: 2022-06-17 19:22:13 +0000
poll(2): Add POLLRDHUP.
Teach poll(2) to support Linux-style POLLRDHUP events for sockets, if
requested. Triggered when the remote peer shuts down writing or closes
its end.
Reviewed by: kib
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D29757
(cherry picked from commit 3aaaa2efde896e19d229ee2cf09fe7e6ab0fbf6e)
---
lib/libc/sys/poll.2 | 14 +++-
sys/kern/uipc_socket.c | 4 +-
sys/sys/poll.h | 1 +
tests/sys/netinet/socket_afinet.c | 141 ++++++++++++++++++++++++++++++++++++++
usr.bin/truss/syscalls.c | 2 +-
5 files changed, 159 insertions(+), 3 deletions(-)
diff --git a/lib/libc/sys/poll.2 b/lib/libc/sys/poll.2
index bea4aac82bd3..fec82db08944 100644
--- a/lib/libc/sys/poll.2
+++ b/lib/libc/sys/poll.2
@@ -28,7 +28,7 @@
.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd February 27, 2019
+.Dd April 27, 2021
.Dt POLL 2
.Os
.Sh NAME
@@ -126,6 +126,15 @@ POLLOUT
should never be present in the
.Fa revents
bitmask at the same time.
+.It POLLRDHUP
+Remote peer closed connection, or shut down writing.
+Unlike
+POLLHUP,
+POLLRDHUP
+must be present in the
+.Fa events
+bitmask to be reported.
+Applies only to stream sockets.
.It POLLNVAL
The file descriptor is not open,
or in capability mode the file descriptor has insufficient rights.
@@ -261,6 +270,9 @@ function conforms to
The
.Fn ppoll
is not specified by POSIX.
+The
+POLLRDHUP
+flag is not specified by POSIX, but is compatible with Linux and illumos.
.Sh HISTORY
The
.Fn poll
diff --git a/sys/kern/uipc_socket.c b/sys/kern/uipc_socket.c
index bbcd5dd30320..8f2122c98ef5 100644
--- a/sys/kern/uipc_socket.c
+++ b/sys/kern/uipc_socket.c
@@ -3581,9 +3581,11 @@ sopoll_generic(struct socket *so, int events, struct ucred *active_cred,
revents |= POLLHUP;
}
}
+ if (so->so_rcv.sb_state & SBS_CANTRCVMORE)
+ revents |= events & POLLRDHUP;
if (revents == 0) {
if (events &
- (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) {
+ (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND | POLLRDHUP)) {
selrecord(td, &so->so_rdsel);
so->so_rcv.sb_flags |= SB_SEL;
}
diff --git a/sys/sys/poll.h b/sys/sys/poll.h
index 6805704ca39f..02347ed09a13 100644
--- a/sys/sys/poll.h
+++ b/sys/sys/poll.h
@@ -71,6 +71,7 @@ struct pollfd {
#if __BSD_VISIBLE
/* General FreeBSD extension (currently only supported for sockets): */
#define POLLINIGNEOF 0x2000 /* like POLLIN, except ignore EOF */
+#define POLLRDHUP 0x4000 /* half shut down */
#endif
/*
diff --git a/tests/sys/netinet/socket_afinet.c b/tests/sys/netinet/socket_afinet.c
index 54585086da23..985d67d83c99 100644
--- a/tests/sys/netinet/socket_afinet.c
+++ b/tests/sys/netinet/socket_afinet.c
@@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
#include <sys/errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
+#include <poll.h>
#include <atf-c.h>
@@ -89,12 +90,152 @@ ATF_TC_BODY(socket_afinet_bind_ok, tc)
close(sd);
}
+ATF_TC_WITHOUT_HEAD(socket_afinet_poll_no_rdhup);
+ATF_TC_BODY(socket_afinet_poll_no_rdhup, tc)
+{
+ int ss, ss2, cs, rc;
+ struct sockaddr_in sin;
+ struct pollfd pfd;
+ int one = 1;
+
+ /* Verify that we don't expose POLLRDHUP if not requested. */
+
+ /* Server setup. */
+ ss = socket(PF_INET, SOCK_STREAM, 0);
+ ATF_CHECK(ss >= 0);
+ rc = setsockopt(ss, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+ ATF_CHECK_EQ(0, rc);
+ bzero(&sin, sizeof(sin));
+ sin.sin_family = AF_INET;
+ sin.sin_len = sizeof(sin);
+ sin.sin_port = htons(6666);
+ sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ rc = bind(ss, (struct sockaddr *)&sin, sizeof(sin));
+ ATF_CHECK_EQ(0, rc);
+ rc = listen(ss, 1);
+ ATF_CHECK_EQ(0, rc);
+
+ /* Client connects, server accepts. */
+ cs = socket(PF_INET, SOCK_STREAM, 0);
+ ATF_CHECK(cs >= 0);
+ rc = connect(cs, (struct sockaddr *)&sin, sizeof(sin));
+ ATF_CHECK_EQ(0, rc);
+ ss2 = accept(ss, NULL, NULL);
+ ATF_CHECK(ss2 >= 0);
+
+ /* Server can write, sees only POLLOUT. */
+ pfd.fd = ss2;
+ pfd.events = POLLIN | POLLOUT;
+ rc = poll(&pfd, 1, 0);
+ ATF_CHECK_EQ(1, rc);
+ ATF_CHECK_EQ(POLLOUT, pfd.revents);
+
+ /* Client closes socket! */
+ rc = close(cs);
+ ATF_CHECK_EQ(0, rc);
+
+ /*
+ * Server now sees POLLIN, but not POLLRDHUP because we didn't ask.
+ * Need non-zero timeout to wait for the FIN to arrive and trigger the
+ * socket to become readable.
+ */
+ pfd.fd = ss2;
+ pfd.events = POLLIN;
+ rc = poll(&pfd, 1, 60000);
+ ATF_CHECK_EQ(1, rc);
+ ATF_CHECK_EQ(POLLIN, pfd.revents);
+
+ close(ss2);
+ close(ss);
+}
+
+ATF_TC_WITHOUT_HEAD(socket_afinet_poll_rdhup);
+ATF_TC_BODY(socket_afinet_poll_rdhup, tc)
+{
+ int ss, ss2, cs, rc;
+ struct sockaddr_in sin;
+ struct pollfd pfd;
+ char buffer;
+ int one = 1;
+
+ /* Verify that server sees POLLRDHUP if it asks for it. */
+
+ /* Server setup. */
+ ss = socket(PF_INET, SOCK_STREAM, 0);
+ ATF_CHECK(ss >= 0);
+ rc = setsockopt(ss, SOL_SOCKET, SO_REUSEPORT, &one, sizeof(one));
+ ATF_CHECK_EQ(0, rc);
+ bzero(&sin, sizeof(sin));
+ sin.sin_family = AF_INET;
+ sin.sin_len = sizeof(sin);
+ sin.sin_port = htons(6666);
+ sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
+ rc = bind(ss, (struct sockaddr *)&sin, sizeof(sin));
+ ATF_CHECK_EQ(0, rc);
+ rc = listen(ss, 1);
+ ATF_CHECK_EQ(0, rc);
+
+ /* Client connects, server accepts. */
+ cs = socket(PF_INET, SOCK_STREAM, 0);
+ ATF_CHECK(cs >= 0);
+ rc = connect(cs, (struct sockaddr *)&sin, sizeof(sin));
+ ATF_CHECK_EQ(0, rc);
+ ss2 = accept(ss, NULL, NULL);
+ ATF_CHECK(ss2 >= 0);
+
+ /* Server can write, so sees POLLOUT. */
+ pfd.fd = ss2;
+ pfd.events = POLLIN | POLLOUT | POLLRDHUP;
+ rc = poll(&pfd, 1, 0);
+ ATF_CHECK_EQ(1, rc);
+ ATF_CHECK_EQ(POLLOUT, pfd.revents);
+
+ /* Client writes two bytes, server reads only one of them. */
+ rc = write(cs, "xx", 2);
+ ATF_CHECK_EQ(2, rc);
+ rc = read(ss2, &buffer, 1);
+ ATF_CHECK_EQ(1, rc);
+
+ /* Server can read, so sees POLLIN. */
+ pfd.fd = ss2;
+ pfd.events = POLLIN | POLLOUT | POLLRDHUP;
+ rc = poll(&pfd, 1, 0);
+ ATF_CHECK_EQ(1, rc);
+ ATF_CHECK_EQ(POLLIN | POLLOUT, pfd.revents);
+
+ /* Client closes socket! */
+ rc = close(cs);
+ ATF_CHECK_EQ(0, rc);
+
+ /*
+ * Server sees Linux-style POLLRDHUP. Note that this is the case even
+ * though one byte of data remains unread.
+ *
+ * This races against the delivery of FIN caused by the close() above.
+ * Sometimes (more likely when run under truss or if another system
+ * call is added in between) it hits the path where sopoll_generic()
+ * immediately sees SBS_CANTRCVMORE, and sometimes it sleeps with flag
+ * SB_SEL so that it's woken up almost immediately and runs again,
+ * which is why we need a non-zero timeout here.
+ */
+ pfd.fd = ss2;
+ pfd.events = POLLRDHUP;
+ rc = poll(&pfd, 1, 60000);
+ ATF_CHECK_EQ(1, rc);
+ ATF_CHECK_EQ(POLLRDHUP, pfd.revents);
+
+ close(ss2);
+ close(ss);
+}
+
ATF_TP_ADD_TCS(tp)
{
ATF_TP_ADD_TC(tp, socket_afinet);
ATF_TP_ADD_TC(tp, socket_afinet_bind_zero);
ATF_TP_ADD_TC(tp, socket_afinet_bind_ok);
+ ATF_TP_ADD_TC(tp, socket_afinet_poll_no_rdhup);
+ ATF_TP_ADD_TC(tp, socket_afinet_poll_rdhup);
return atf_no_error();
}
diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c
index a84f64f70ff7..06e984de3fe8 100644
--- a/usr.bin/truss/syscalls.c
+++ b/usr.bin/truss/syscalls.c
@@ -736,7 +736,7 @@ struct xlat {
static struct xlat poll_flags[] = {
X(POLLSTANDARD) X(POLLIN) X(POLLPRI) X(POLLOUT) X(POLLERR)
X(POLLHUP) X(POLLNVAL) X(POLLRDNORM) X(POLLRDBAND)
- X(POLLWRBAND) X(POLLINIGNEOF) XEND
+ X(POLLWRBAND) X(POLLINIGNEOF) X(POLLRDHUP) XEND
};
static struct xlat sigaction_flags[] = {