[LTP] [PATCH v1] Add epoll_wait06 test

[Andrea Cervesato]

Hi,
please ignore v1 and consider v2 that is fixing make check.

On 10/10/22 16:18, Andrea Cervesato wrote:
> This test verifies EPOLLET functionality.
>
> Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
> ---
>   .../kernel/syscalls/epoll_wait/.gitignore     |  1 +
>   .../kernel/syscalls/epoll_wait/epoll_wait06.c | 97 +++++++++++++++++++
>   2 files changed, 98 insertions(+)
>   create mode 100644 testcases/kernel/syscalls/epoll_wait/epoll_wait06.c
>
> diff --git a/testcases/kernel/syscalls/epoll_wait/.gitignore b/testcases/kernel/syscalls/epoll_wait/.gitignore
> index ab5a9c010..8c5ed7c5c 100644
> --- a/testcases/kernel/syscalls/epoll_wait/.gitignore
> +++ b/testcases/kernel/syscalls/epoll_wait/.gitignore
> @@ -3,3 +3,4 @@ epoll_wait02
>   epoll_wait03
>   epoll_wait04
>   epoll_wait05
> +epoll_wait06
> diff --git a/testcases/kernel/syscalls/epoll_wait/epoll_wait06.c b/testcases/kernel/syscalls/epoll_wait/epoll_wait06.c
> new file mode 100644
> index 000000000..ef3883e83
> --- /dev/null
> +++ b/testcases/kernel/syscalls/epoll_wait/epoll_wait06.c
> @@ -0,0 +1,97 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2022 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
> + */
> +
> +/*\
> + * [Description]
> + *
> + * Verify that edge triggered behavior is correctly handled by epoll.
> + *
> + * [Algorithm]
> + *
> + * 1. The file descriptor that represents the read side of a pipe (rfd) is
> + *    registered on the epoll instance.
> + * 2. A pipe writer writes 2 kB of data on the write side of the pipe.
> + * 3. A call to epoll_wait(2) is done that will return rfd as a ready file
> + *    descriptor.
> + * 4. The pipe reader reads 1 kB of data from rfd.
> + * 5. A call to epoll_wait(2) should fail because there's data left to read.
> + */
> +
> +#include <poll.h>
> +#include <sys/epoll.h>
> +#include "tst_test.h"
> +
> +#define WRITE_SIZE 2048
> +#define READ_SIZE WRITE_SIZE / 2
> +
> +static int fds[2];
> +static int epfd;
> +
> +static void cleanup(void)
> +{
> +	if (epfd > 0)
> +		SAFE_CLOSE(epfd);
> +
> +	if (fds[0] > 0)
> +		SAFE_CLOSE(fds[0]);
> +
> +	if (fds[1] > 0)
> +		SAFE_CLOSE(fds[1]);
> +}
> +
> +static void run(void)
> +{
> +	int res;
> +	char buff[WRITE_SIZE];
> +	struct epoll_event evt_receive;
> +	struct epoll_event evt_request;
> +
> +	SAFE_PIPE(fds);
> +
> +	evt_request.events = EPOLLIN | EPOLLET;
> +	evt_request.data.fd = fds[0];
> +
> +	epfd = epoll_create(2);
> +	if (epfd == -1)
> +		tst_brk(TBROK | TERRNO, "fail to create epoll instance");
> +
> +	tst_res(TINFO, "Polling channel with EPOLLET");
> +
> +	res = epoll_ctl(epfd, EPOLL_CTL_ADD, fds[0], &evt_request);
> +	if (res == -1)
> +		tst_brk(TBROK | TERRNO, "epoll_ctl failure");
> +
> +	tst_res(TINFO, "Write bytes on channel");
> +
> +	memset(buff, 'a', WRITE_SIZE);
> +	SAFE_WRITE(0, fds[1], buff, WRITE_SIZE);
> +
> +	res = epoll_wait(epfd, &evt_receive, 1, 2000);
> +	if (res <= 0) {
> +		tst_res(TFAIL | TERRNO, "epoll_wait() returned %i", res);
> +		goto close;
> +	}
> +
> +	if ((evt_receive.events & EPOLLIN) == 0) {
> +		tst_brk(TFAIL, "No data received");
> +		goto close;
> +	}
> +
> +	tst_res(TINFO, "Received EPOLLIN event. Read half bytes from channel");
> +
> +	memset(buff, 0, READ_SIZE);
> +	SAFE_READ(1, evt_receive.data.fd, buff, READ_SIZE);
> +
> +	TST_EXP_EQ_LI(epoll_wait(epfd, &evt_receive, 1, 10), 0);
> +
> +close:
> +	SAFE_CLOSE(fds[0]);
> +	SAFE_CLOSE(fds[1]);
> +}
> +
> +static struct tst_test test = {
> +	.cleanup = cleanup,
> +	.test_all = run,
> +};