[v2] socket: Add new test for shutdown

  This commit adds shutdown test with SHUT_RD, SHUT_WR, SHUT_RDWR for an
UNIX socket connection.
---
Changes from v1:
 initialize peer_len in do_test_shut_rdwr function.
---
 socket/Makefile       |   1 +
 socket/tst-shutdown.c | 245 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 246 insertions(+)
 create mode 100644 socket/tst-shutdown.c
  

Sergey Kolosov <skolosov@redhat.com> writes:
> This commit adds shutdown test with SHUT_RD, SHUT_WR, SHUT_RDWR for an
> UNIX socket connection.

Two changes needed:

1. Comments need two spaces after period.
2. SHUT_RDWR test is missing test for SHUT_RD portion.

> +  tst-shutdown \

Ok.

> diff --git a/socket/tst-shutdown.c b/socket/tst-shutdown.c
> +/* Test the shutdown function.
> +   Copyright (C) 2024 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <arpa/inet.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <signal.h>
> +#include <stdbool.h>
> +#include <support/check.h>
> +#include <support/xsocket.h>
> +#include <support/xunistd.h>
> +#include <sys/socket.h>
> +#include <stdio.h>
> +
> +#include <fcntl.h>
> +#include <string.h>
> +#include <support/support.h>
> +#include <support/xsignal.h>
> +#include <support/temp_file.h>

Ok.

> +struct connection
> +{
> +  int sockets[2];
> +};
> +
> +void
> +establish_connection (struct connection *conn)
> +{
> +  if (socketpair (AF_UNIX, SOCK_STREAM, 0, conn->sockets) != 0)
> +    {
> +      FAIL_EXIT1 ("socketpair (AF_UNIX, SOCK_STREAM, 0): %m\n");
> +    }
> +}

Ok.

> +void
> +close_connection (struct connection *conn)
> +{
> +  xclose (conn->sockets[0]);
> +  xclose (conn->sockets[1]);
> +}

Ok.

> +/*  Open a file and check that shutdown fails with the ENOTSOCK error code. */

Note two spaces after period please.

> +void
> +do_test_enotsock (void)
> +{
> +  char *tmp_dir = support_create_temp_directory ("tst-shutdown-");
> +  char *path_to_file = xasprintf ("%s/shutdown.txt", tmp_dir);
> +
> +  /* open file and check that shutdown will fail with ENOTSOCK. */
> +  int fd = xopen (path_to_file, O_CREAT | O_RDWR, S_IRWXU);

Ok.

> +  int result = shutdown (fd, SHUT_RD);
> +  if (result == 0 || errno != ENOTSOCK)
> +    {
> +      FAIL_EXIT1 ("shutdown should fail with ENOTSOCK");
> +    }
> +  xclose (fd);

Ok.

> +  /* remove file, temp directory will be removed itself. */
> +  xunlink (path_to_file);
> +}

Ok.

> +/* Test shutdown with SHUT_RD. */
> +void
> +do_test_shut_rd (void)
> +{
> +  struct connection conn;
> +  const char *str = "AAAAAAA";
> +  int len = 8;
> +  int ret;
> +  void *s_buf = xmalloc (len);
> +  bzero (s_buf, len);
> +
> +  establish_connection (&conn);
> +  int server = conn.sockets[0];
> +  int client = conn.sockets[1];

Ok.

> +  /* call shutdown with SHUT_RD on server socket. */
> +  if (shutdown (server, SHUT_RD) != 0)
> +    {
> +      FAIL_EXIT1 ("shutdown with SHUT_RD on socket %d failed", server);
> +    }

Reads on server should return 0 now, ok.

> +  ret = send (server, str, len, 0);
> +  if (ret <= 0)
> +    {
> +      FAIL_EXIT1 ("send (%d, data, %d): %m", server, len);
> +    }

writes to server should still be ok, ok.

> +  ret = recv (client, s_buf, len, 0);
> +  if (ret <= 0)
> +    {
> +      FAIL_EXIT1 ("recv (%d, data, %d): %m", client, len);
> +    }

Read data just sent, ok.

> +  TEST_COMPARE_BLOB (str, len, s_buf, len);

Ok.

> +  /* send data should be disallowed on shutdown socket. */
> +  errno = 0;
> +  ret = send (client, str, len, MSG_NOSIGNAL);
> +  if (ret >= 0 || errno != EPIPE)
> +    {
> +      FAIL_EXIT1 ("Send on SHUT_RD socket should be disallowed: %m");
> +    }

Ok.

> +  /* recv should return zero and no error. */
> +  errno = 0;
> +  ret = recv (server, s_buf, len, 0);
> +  if (ret != 0 || errno != 0)
> +    {
> +      FAIL_EXIT1 ("recv should return 0 without error: %m");
> +    }

Ok.

> +  close_connection (&conn);
> +}

Ok.

> +/* Test shutdown with SHUT_WR. */
> +void
> +do_test_shut_wr (void)
> +{
> +  struct connection conn;
> +  const char *str1 = "CCCCCCC";
> +  const char *str2 = "DDDDDDD";
> +  const char *str3 = "EEEEEEE";
> +  int len = 8;
> +  int ret;
> +  void *c_buf = xmalloc (len);
> +  void *s_buf = xmalloc (len);
> +
> +  establish_connection (&conn);
> +  int server = conn.sockets[0];
> +  int client = conn.sockets[1];

Ok.

> +  xwrite (client, str1, len);

pre-fill, ok.

> +  if (shutdown (client, SHUT_WR) != 0)
> +    {
> +      FAIL_EXIT1 ("shutdown with SHUT_WR on socket %d failed", client);
> +    }

No more writes, ok.

> +  ret = send (client, str2, len, MSG_NOSIGNAL);
> +  if (ret >= 0)
> +    {
> +      FAIL_EXIT1 ("send on SHUT_WR socket should fail");
> +    }

Ok.

> +  /* read data written before shutdown and check if it's correct. */
> +  xread (server, s_buf, len);
> +  TEST_COMPARE_BLOB (str1, len, s_buf, len);

Ok.

> +  /* Second read should return zero without error. */
> +  errno = 0;
> +  if (read (server, s_buf, len) != 0 || errno != 0)
> +    {
> +      FAIL_EXIT1 ("read after shutdown should return zero without error: %m");
> +    }

Ok.

> +  /* write some data to socket and check it still can be read on other side. */
> +  memcpy (s_buf, str3, len);
> +  xwrite (server, s_buf, len);
> +
> +  xread (client, c_buf, len);
> +  TEST_COMPARE_BLOB (s_buf, len, c_buf, len);

Ok.

> +  close_connection (&conn);
> +}

Ok.

> +/* Test shutdown with SHUT_RDWR. */
> +void
> +do_test_shut_rdwr (void)
> +{
> +  struct connection conn;
> +  struct sockaddr peer;
> +  socklen_t peer_len = sizeof (peer);
> +
> +  const char *str = "GGGGGGG";
> +  int len = 8;
> +  int ret;
> +  void *s_buf = xmalloc (len);
> +  bzero (s_buf, len);
> +
> +  establish_connection (&conn);
> +  int server = conn.sockets[0];
> +  int client = conn.sockets[1];

Ok.

> +  xwrite (client, str, len);

Fill buffer, ok

> +  if (shutdown (client, SHUT_RDWR) != 0)
> +    {
> +      FAIL_EXIT1 ("shutdown with SHUT_RDWR on socket %d failed", client);
> +    }

Ok.

> +  /* verify that socket is still connected. */
> +  xgetsockname (client, &peer, &peer_len);

Ok.

> +  /* read data written before shutdown. */
> +  xread (server, s_buf, len);
> +  TEST_COMPARE_BLOB (s_buf, len, str, len);

Ok.

> +  /* second read should return zero, but no error. */
> +  errno = 0;
> +  if (read (server, s_buf, len) != 0 || errno != 0)
> +    {
> +      FAIL_EXIT1 ("read after shutdown should return zero without error: %m");
> +    }

This tests the SHUT_WR side, Ok.

> +  /* send some data to shutdown socket and expect error. */
> +  errno = 0;
> +  ret = send (client, str, len, MSG_NOSIGNAL);
> +  if (ret >= 0 || errno != EPIPE)
> +    {
> +      FAIL_EXIT1 ("send to RDWR shutdown socket should fail with EPIPE");
> +    }

This also tests the SHUT_WR side.

> +  close_connection (&conn);
> +}

Where is the test for the SHUT_RD side?

> +static int
> +do_test (void)
> +{
> +  do_test_enotsock ();
> +  do_test_shut_rd ();
> +  do_test_shut_wr ();
> +  do_test_shut_rdwr ();
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>

Ok.