[LTP] [PATCH v4] Add epoll_wait05 test

[LTP] [PATCH v4] Add epoll_wait05 test

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

This test verifies that epoll receives EPOLLRDHUP event when we hang
a reading half-socket we are polling on.

Implements: https://github.com/linux-test-project/ltp/issues/860
Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 runtest/syscalls                              |   1 +
 .../kernel/syscalls/epoll_wait/.gitignore     |   1 +
 .../kernel/syscalls/epoll_wait/epoll_wait05.c | 126 ++++++++++++++++++
 3 files changed, 128 insertions(+)
 create mode 100644 testcases/kernel/syscalls/epoll_wait/epoll_wait05.c

diff --git a/runtest/syscalls b/runtest/syscalls
index 7af2842f3..27819b41b 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -175,6 +175,7 @@ epoll_wait01 epoll_wait01
 epoll_wait02 epoll_wait02
 epoll_wait03 epoll_wait03
 epoll_wait04 epoll_wait04
+epoll_wait05 epoll_wait05
 epoll_pwait01 epoll_pwait01
 epoll_pwait02 epoll_pwait02
 epoll_pwait03 epoll_pwait03
diff --git a/testcases/kernel/syscalls/epoll_wait/.gitignore b/testcases/kernel/syscalls/epoll_wait/.gitignore
index 222955dd2..ab5a9c010 100644
--- a/testcases/kernel/syscalls/epoll_wait/.gitignore
+++ b/testcases/kernel/syscalls/epoll_wait/.gitignore
@@ -2,3 +2,4 @@ epoll_wait01
 epoll_wait02
 epoll_wait03
 epoll_wait04
+epoll_wait05
diff --git a/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c b/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c
new file mode 100644
index 000000000..a055a5885
--- /dev/null
+++ b/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2023 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify that epoll receives EPOLLRDHUP event when we hang a reading
+ * half-socket we are polling on.
+ *
+ * As reference please check https://lwn.net/Articles/864947/
+ */
+
+#include "tst_test.h"
+#include "tst_net.h"
+#include "tst_epoll.h"
+
+static int epfd;
+static int sockfd_client;
+static int sockfd_server;
+static in_port_t *sock_port;
+
+static void create_server(void)
+{
+	int sockfd_server;
+	socklen_t len;
+	struct sockaddr_in serv_addr;
+	struct sockaddr_in sin;
+
+	tst_init_sockaddr_inet_bin(&serv_addr, INADDR_ANY, 0);
+
+	sockfd_server = SAFE_SOCKET(AF_INET, SOCK_STREAM, 0);
+	SAFE_BIND(sockfd_server, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
+	SAFE_LISTEN(sockfd_server, 10);
+
+	len = sizeof(sin);
+	memset(&sin, 0, sizeof(struct sockaddr_in));
+	SAFE_GETSOCKNAME(sockfd_server, (struct sockaddr *)&sin, &len);
+
+	*sock_port = ntohs(sin.sin_port);
+
+	tst_res(TINFO, "Listening on port %d", *sock_port);
+
+	TST_CHECKPOINT_WAKE_AND_WAIT(0);
+
+	SAFE_CLOSE(sockfd_server);
+}
+
+static void run(void)
+{
+	struct sockaddr_in client_addr;
+	struct epoll_event evt_req;
+	struct epoll_event evt_rec;
+
+	if (!SAFE_FORK()) {
+		create_server();
+		return;
+	}
+
+	TST_CHECKPOINT_WAIT(0);
+
+	tst_res(TINFO, "Connecting to port %d", *sock_port);
+
+	sockfd_client = SAFE_SOCKET(AF_INET, SOCK_STREAM, 0);
+
+	tst_init_sockaddr_inet(&client_addr, "127.0.0.1", *sock_port);
+
+	SAFE_CONNECT(sockfd_client,
+		(struct sockaddr *)&client_addr,
+		sizeof(client_addr));
+
+	tst_res(TINFO, "Polling on socket");
+
+	epfd = SAFE_EPOLL_CREATE1(0);
+	evt_req.events = EPOLLRDHUP;
+	SAFE_EPOLL_CTL(epfd, EPOLL_CTL_ADD, sockfd_client, &evt_req);
+
+	tst_res(TINFO, "Hang socket");
+
+	TST_EXP_PASS_SILENT(shutdown(sockfd_client, SHUT_RD));
+	SAFE_EPOLL_WAIT(epfd, &evt_rec, 1, 2000);
+
+	if (evt_rec.events & EPOLLRDHUP)
+		tst_res(TPASS, "Received EPOLLRDHUP");
+	else
+		tst_res(TFAIL, "EPOLLRDHUP has not been received");
+
+	SAFE_CLOSE(epfd);
+	SAFE_CLOSE(sockfd_client);
+
+	TST_CHECKPOINT_WAKE(0);
+}
+
+static void setup(void)
+{
+	sock_port = SAFE_MMAP(NULL, sizeof(in_port_t), PROT_READ | PROT_WRITE,
+		MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+}
+
+static void cleanup(void)
+{
+	if (sock_port)
+		SAFE_MUNMAP(sock_port, sizeof(in_port_t));
+
+	if (fcntl(sockfd_client, F_GETFD) > 0)
+		SAFE_CLOSE(sockfd_client);
+
+	if (fcntl(sockfd_server, F_GETFD) > 0)
+		SAFE_CLOSE(sockfd_server);
+
+	if (fcntl(epfd, F_GETFD) > 0)
+		SAFE_CLOSE(epfd);
+}
+
+static struct tst_test test = {
+	.setup = setup,
+	.cleanup = cleanup,
+	.test_all = run,
+	.forks_child = 1,
+	.needs_checkpoints = 1,
+	.tags = (const struct tst_tag[]) {
+		{"linux-git", "3a34b13a88ca"},
+		{},
+	}
+};
-- 
2.35.3


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Re: [LTP] [PATCH v4] Add epoll_wait05 test

[Cyril Hrubis]

Hi!
> This test verifies that epoll receives EPOLLRDHUP event when we hang
> a reading half-socket we are polling on.
> 
> Implements: https://github.com/linux-test-project/ltp/issues/860
> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>

...

> +/*\
> + * [Description]
> + *
> + * Verify that epoll receives EPOLLRDHUP event when we hang a reading
> + * half-socket we are polling on.
> + *
> + * As reference please check https://lwn.net/Articles/864947/

I'm a bit confused here, the test itself looks good, but it references
an article and a kernel commit that changed how polling on _pipe_ works.
The kernel change literally changes only pipe_write() in fs/pipe.c and
this test actually tests inet sockets.

I guess that the confusion is caused by the fact that the github issue
referenced the lwn.net article as a reason why we need more epoll
coverage, but these tests are not directly related to that commit at
all.

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v4] Add epoll_wait05 test

[Andrea Cervesato via ltp]

Hi,

On 8/29/23 09:25, Cyril Hrubis wrote:
> Hi!
>> This test verifies that epoll receives EPOLLRDHUP event when we hang
>> a reading half-socket we are polling on.
>>
>> Implements: https://github.com/linux-test-project/ltp/issues/860
>> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
> ...
>
>> +/*\
>> + * [Description]
>> + *
>> + * Verify that epoll receives EPOLLRDHUP event when we hang a reading
>> + * half-socket we are polling on.
>> + *
>> + * As reference please check https://lwn.net/Articles/864947/
> I'm a bit confused here, the test itself looks good, but it references
> an article and a kernel commit that changed how polling on _pipe_ works.
> The kernel change literally changes only pipe_write() in fs/pipe.c and
> this test actually tests inet sockets.
>
> I guess that the confusion is caused by the fact that the github issue
> referenced the lwn.net article as a reason why we need more epoll
> coverage, but these tests are not directly related to that commit at
> all.
>
If patch is fine, is it possible to push it removing the reference?

Thanks,
Andrea



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Re: [LTP] [PATCH v4] Add epoll_wait05 test

[Cyril Hrubis]

Hi!
> If patch is fine, is it possible to push it removing the reference?

Sure, will do.

-- 
Cyril Hrubis
chrubis@suse.cz

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Re: [LTP] [PATCH v4] Add epoll_wait05 test

[Cyril Hrubis]

Hi!
> If patch is fine, is it possible to push it removing the reference?

Pushed with one minor change, thanks.

I've also added check that epoll_wait() returns 1 otherwise the content
of the returned event is not valid.

Full diff:

diff --git a/testcases/kernel/mce-test b/testcases/kernel/mce-test
index 95e136a3b..0b4e77570 160000
--- a/testcases/kernel/mce-test
+++ b/testcases/kernel/mce-test
@@ -1 +1 @@
-Subproject commit 95e136a3b0cde818448d5fcff5bf75d58600dc0d
+Subproject commit 0b4e7757068381139db1317c07bdb7532196ef76
diff --git a/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c b/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c
index a055a5885..d06a024ff 100644
--- a/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c
+++ b/testcases/kernel/syscalls/epoll_wait/epoll_wait05.c
@@ -8,8 +8,6 @@
  *
  * Verify that epoll receives EPOLLRDHUP event when we hang a reading
  * half-socket we are polling on.
- *
- * As reference please check https://lwn.net/Articles/864947/
  */
 
 #include "tst_test.h"
@@ -52,6 +50,7 @@ static void run(void)
 	struct sockaddr_in client_addr;
 	struct epoll_event evt_req;
 	struct epoll_event evt_rec;
+	int ret;
 
 	if (!SAFE_FORK()) {
 		create_server();
@@ -79,13 +78,18 @@ static void run(void)
 	tst_res(TINFO, "Hang socket");
 
 	TST_EXP_PASS_SILENT(shutdown(sockfd_client, SHUT_RD));
-	SAFE_EPOLL_WAIT(epfd, &evt_rec, 1, 2000);
+	ret = SAFE_EPOLL_WAIT(epfd, &evt_rec, 1, 2000);
+	if (ret != 1) {
+		tst_res(TFAIL, "Wrong number of events reported %i", ret);
+		goto exit;
+	}
 
 	if (evt_rec.events & EPOLLRDHUP)
 		tst_res(TPASS, "Received EPOLLRDHUP");
 	else
 		tst_res(TFAIL, "EPOLLRDHUP has not been received");
 
+exit:
 	SAFE_CLOSE(epfd);
 	SAFE_CLOSE(sockfd_client);
 
@@ -119,8 +123,4 @@ static struct tst_test test = {
 	.test_all = run,
 	.forks_child = 1,
 	.needs_checkpoints = 1,
-	.tags = (const struct tst_tag[]) {
-		{"linux-git", "3a34b13a88ca"},
-		{},
-	}
 };

-- 
Cyril Hrubis
chrubis@suse.cz

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