[LTP] [PATCH v3 3/3] syscalls/pipe2_03: Add new test for pipe2 O_DIRECT flag

Li Wang liwang@redhat.com
Tue Apr 21 11:53:29 CEST 2020


On Thu, Apr 16, 2020 at 3:29 PM Yang Xu <xuyang2018.jy@cn.fujitsu.com>
wrote:

> Signed-off-by: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
> ---
>  runtest/syscalls                           |   1 +
>  testcases/kernel/syscalls/pipe2/.gitignore |   1 +
>  testcases/kernel/syscalls/pipe2/pipe2_03.c | 157 +++++++++++++++++++++
>  3 files changed, 159 insertions(+)
>  create mode 100644 testcases/kernel/syscalls/pipe2/pipe2_03.c
>
> diff --git a/runtest/syscalls b/runtest/syscalls
> index 44254d7da..4d8ebc5a3 100644
> --- a/runtest/syscalls
> +++ b/runtest/syscalls
> @@ -912,6 +912,7 @@ pipe13 pipe13
>
>  pipe2_01 pipe2_01
>  pipe2_02 pipe2_02
> +pipe2_03 pipe2_03
>
>  pivot_root01 pivot_root01
>
> diff --git a/testcases/kernel/syscalls/pipe2/.gitignore
> b/testcases/kernel/syscalls/pipe2/.gitignore
> index 786222de2..4cc5acaf1 100644
> --- a/testcases/kernel/syscalls/pipe2/.gitignore
> +++ b/testcases/kernel/syscalls/pipe2/.gitignore
> @@ -1,3 +1,4 @@
>  /pipe2_01
>  /pipe2_02
>  /pipe2_02_child
> +/pipe2_03
> diff --git a/testcases/kernel/syscalls/pipe2/pipe2_03.c
> b/testcases/kernel/syscalls/pipe2/pipe2_03.c
> new file mode 100644
> index 000000000..0b5d37dd0
> --- /dev/null
> +++ b/testcases/kernel/syscalls/pipe2/pipe2_03.c
> @@ -0,0 +1,157 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2020 FUJITSU LIMITED. All rights reserved.
> + * Author: Yang Xu <xuyang2018.jy@cn.fujitsu.com>
> + *
> + * This case is designed to test the basic functionality about the
> + * O_DIRECT flag of pipe2.
> + *
> + * It includes three sub tests.
> + * 1) Each write(2) to the pipe is dealt with as a separate packet, and
> + * read(2)s from the pipe will read one packet at a time.
> + * 2) Writes of greater than PIPE_BUF bytes (see pipe(7)) will be split
> + * into multiple packet.
> + * 3)If a read(2) specifies a buffer size that is smaller than the next
> + * packet, then the requested number of bytes are read, and the excess
> + * bytes in the packet are discarded.
> + */
> +#define _GNU_SOURCE
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <linux/limits.h>
> +#include "lapi/fcntl.h"
> +#include "tst_test.h"
> +
> +static int fds[2], packet_num, pipe_size;
> +static char *wrbuf;
> +static char *rdbuf;
> +static void check_peer_rw(void);
> +static void check_split(void);
> +static void check_discard(void);
> +
> +static void (*test_func[])(void) = {check_peer_rw, check_split,
> check_discard};
> +
> +static void check_peer_rw(void)
> +{
> +       int i, pid;
> +
> +       SAFE_PIPE2(fds, O_DIRECT | O_NONBLOCK);
> +       for (i = 0; i < packet_num; i++)
> +               SAFE_WRITE(1, fds[1], "x", 1);
> +
> +       TEST(write(fds[1], "x", 1));
> +       if (TST_RET != -1) {
> +               tst_res(TFAIL, "write succeeded unexpectedly");
> +       } else {
> +               if (TST_ERR == EAGAIN)
> +                       tst_res(TPASS, "Each write(2) uses a separate
> packet");
> +               else
> +                       tst_res(TFAIL | TTERRNO, "write failed, expected
> EAGAIN but got");
> +       }
> +       pid = SAFE_FORK();
> +       if (!pid) {
> +               memset(rdbuf, 0, pipe_size);
> +               for (i = 0; i < packet_num; i++) {
> +                       TEST(SAFE_READ(0, fds[0], rdbuf, pipe_size));
> +                       if (TST_RET != 1)
> +                               tst_res(TFAIL,
> +                                       "Each read(2) doesn't read a
> separate packet, return %ld", TST_RET);
> +               }
> +               tst_res(TPASS, "Each read(2) reads a separate packet");
>

I would add _exit(0); at the end of the child.
+               _exit(0);

+       }
>

And move the tst_reap_children() from the main process to here.

+       tst_reap_children();
+       SAFE_CLOSE(fds[0]);
+       SAFE_CLOSE(fds[1]);



> +}
> +
> +static void check_split(void)
> +{
> +       int i, pid;
> +
> +       SAFE_PIPE2(fds, O_DIRECT);
> +       SAFE_WRITE(1, fds[1], wrbuf, PIPE_BUF * 2);
> +
> +       pid = SAFE_FORK();
> +       if (!pid) {
> +               memset(rdbuf, 0, pipe_size);
> +               for (i = 0; i < 2; i++) {
> +                       TEST(SAFE_READ(0, fds[0], rdbuf, pipe_size));
> +                       if (TST_RET != PIPE_BUF)
> +                               tst_res(TFAIL,
> +                                       "write(higner than PIPE_BUF) split
> into multiple packet, return %ld", TST_RET);
> +               }
> +               tst_res(TPASS, "write(higner than PIPE_BUF) split into
> multiple packet");
>

+               _exit(0);

+       }
>

+       tst_reap_children();
+       SAFE_CLOSE(fds[0]);
+       SAFE_CLOSE(fds[1]);


> +}
> +
> +static void check_discard(void)
> +{
> +       int pid;
> +       char tmp_buf[20];
> +       char tmp_secondbuf[20];
> +
> +       SAFE_PIPE2(fds, O_DIRECT);
> +       SAFE_WRITE(1, fds[1], wrbuf, PIPE_BUF);
> +       SAFE_WRITE(1, fds[1], "1", 1);
> +
> +       pid = SAFE_FORK();
> +       if (!pid) {
> +               TEST(SAFE_READ(0, fds[0], tmp_buf, 20));
> +               if (TST_RET != 20)
> +                       tst_res(TFAIL,
> +                               "the excess bytes in the packet isn't
> discarded by read, return %ld", TST_RET);
> +               TEST(SAFE_READ(0, fds[0], tmp_secondbuf, 20));
> +               if (TST_RET == 1) {
> +                       if (!strcmp(tmp_secondbuf, "1"))
> +                               tst_res(TPASS,
> +                                       "the excess bytes in the packet is
> discarded by read, only read 1");
> +                       else
> +                               tst_res(TFAIL,
> +                                       "the excess bytes in the packet is
> discarded by read, expect 1 got %s", tmp_secondbuf);
> +               }
>

+               _exit(0);


> +       }
>

+       tst_reap_children();
+       SAFE_CLOSE(fds[0]);
+       SAFE_CLOSE(fds[1]);

+}
> +
> +static void verify_pipe2(unsigned int n)
> +{
> +       int pid;
> +
> +       pid = SAFE_FORK();
>

Why we need fork() here? I don't see any necessary reason for twice fork in
the main process.



> +       if (pid == 0) {
> +               (*test_func[n])();
>


> +               tst_reap_children();
> +               SAFE_CLOSE(fds[0]);
> +               SAFE_CLOSE(fds[1]);
>

I tend to move the cloese(fd) to the test process to nearby pipe2().
Otherwise, it causes an unclear error like:

# ./pipe2_03
tst_test.c:1246: INFO: Timeout per run is 0h 05m 00s
pipe2_03.c:48: PASS: Each write(2) uses a separate packet
pipe2_03.c:61: PASS: Each read(2) reads a separate packet
pipe2_03.c:81: PASS: write(higner than PIPE_BUF) split into multiple packet
pipe2_03.c:108: FAIL: the excess bytes in the packet is discarded by read,
expect 1 got 1%A



> +       }
> +       tst_reap_children();
> +}
> +
> +static void setup(void)
> +{
> +       SAFE_PIPE2(fds, O_DIRECT);
> +       pipe_size = SAFE_FCNTL(fds[1], F_GETPIPE_SZ);
> +       wrbuf = SAFE_MALLOC(PIPE_BUF * 2);
> +       rdbuf = SAFE_MALLOC(pipe_size);
> +       memset(wrbuf, 'x', PIPE_BUF * 2);
> +       packet_num = pipe_size / PIPE_BUF;
> +       SAFE_CLOSE(fds[0]);
> +       SAFE_CLOSE(fds[1]);
> +}
> +
> +static void cleanup(void)
> +{
> +       if (fds[0] > 0)
> +               SAFE_CLOSE(fds[0]);
> +       if (fds[1] > 0)
> +               SAFE_CLOSE(fds[1]);
> +       if (wrbuf)
> +               free(wrbuf);
> +       if (rdbuf)
> +               free(rdbuf);
> +}
> +
> +static struct tst_test test = {
> +       .setup = setup,
> +       .cleanup = cleanup,
> +       .forks_child = 1,
> +       .test = verify_pipe2,
> +       .tcnt = ARRAY_SIZE(test_func),
> +};
> --
> 2.23.0
>
>
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
>
>

-- 
Regards,
Li Wang
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