misc: Add new test for daemon

This commit adds a new testcase for the daemon function.
---
The dev_null_redir function may be too linux specific.  Not sure about
a better way to do it.
---
 misc/Makefile     |   1 +
 misc/tst-daemon.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 156 insertions(+)
 create mode 100644 misc/tst-daemon.c

On 27/06/24 13:20, Martin Cermak wrote:
> This commit adds a new testcase for the daemon function.
> ---
> The dev_null_redir function may be too linux specific.  Not sure about
> a better way to do it.

This new tests has failed for some reason on aarch64/armhf buildbot [1][2].
The log does not show much information though [2]

FAIL: misc/tst-daemon
original exit status 127

Usually '127' means a SEGFAULT.

[1] https://patchwork.sourceware.org/project/glibc/patch/20240627162005.407679-1-mcermak@redhat.com/
[2] https://ci.linaro.org/job/tcwg_glibc_check--master-aarch64-precommit/2000/artifact/artifacts/artifacts.precommit/00-sumfiles/


> ---
>  misc/Makefile     |   1 +
>  misc/tst-daemon.c | 155 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 156 insertions(+)
>  create mode 100644 misc/tst-daemon.c
> 
> diff --git a/misc/Makefile b/misc/Makefile
> index c273ec6974..7313f9122d 100644
> --- a/misc/Makefile
> +++ b/misc/Makefile
> @@ -232,6 +232,7 @@ gpl2lgpl := \
>  tests := \
>    bug-hsearch1 \
>    bug18240 \
> +  tst-daemon \
>    tst-dbl-efgcvt \
>    tst-dirname \
>    tst-empty \
> diff --git a/misc/tst-daemon.c b/misc/tst-daemon.c
> new file mode 100644
> index 0000000000..9ab72781e1
> --- /dev/null
> +++ b/misc/tst-daemon.c
> @@ -0,0 +1,155 @@
> +/* Tests for daemon.
> +   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 <errno.h>
> +#include <error.h>
> +#include <stdlib.h>
> +#include <wait.h>
> +#include <support/check.h>
> +#include <string.h>
> +#include <stdio.h>
> +
> +/* Define pipe communication encoding.  */
> +#define STATUS_PASS 'p'
> +#define STATUS_FAIL 'f'
> +
> +/* Check if given file descriptor is redirected to /dev/null.  */
> +unsigned char
> +dev_null_redir (FILE * f)
> +{
> +  char b1[1024];
> +  char b2[1024];
> +  ssize_t len;
> +
> +  int fd = fileno (f);
> +
> +  len = snprintf (b1, sizeof (b1), "/proc/self/fd/%d", fd);
> +  if (len < 0 || len >= sizeof (b1))
> +    return 1;
> +
> +  len = readlink (b1, b2, sizeof (b2) - 1);
> +  if (len < 0)
> +    return 1;
> +
> +  b2[len] = '\0';
> +
> +  if (strcmp (b2, "/dev/null") != 0)
> +    return 1;
> +
> +  return 0;
> +}
> +
> +/* Run one daemon test with specified parameters.  */
> +void
> +test_daemon (int nochdir, int noclose)
> +{
> +  pid_t pid;
> +  int status;
> +  int pipefd[2];
> +  char buf;
> +
> +  if (pipe (pipefd) == -1)
> +      error (EXIT_FAILURE, errno, "failed to create the pipe");
> +
> +  pid = fork ();
> +  if (pid == 0)
> +  {
> +    /* This is the child.  */
> +    char cwd[1024];
> +    char origcwd[1024];
> +    char retval = STATUS_PASS;
> +
> +    getcwd (origcwd, sizeof (origcwd));
> +
> +    /* Daemonize the child.  */
> +    if (daemon (nochdir, noclose) != 0)
> +      retval = STATUS_FAIL;
> +
> +    switch (nochdir)
> +    {
> +      case 0:
> +        getcwd (cwd, sizeof (cwd));
> +        if (strcmp (cwd, "/") != 0)
> +          retval = STATUS_FAIL;
> +        break;
> +      default:
> +        getcwd (cwd, sizeof (cwd));
> +        if (strcmp (cwd, origcwd) != 0)
> +          retval = STATUS_FAIL;
> +    }
> +
> +    switch (noclose)
> +    {
> +      case 0:
> +        if (dev_null_redir (stdin) != 0)
> +          retval = STATUS_FAIL;
> +        if (dev_null_redir (stdout) != 0)
> +          retval = STATUS_FAIL;
> +        if (dev_null_redir (stderr) != 0)
> +          retval = STATUS_FAIL;
> +        break;
> +      default:
> +        if (dev_null_redir (stdin) != 1)
> +          retval = STATUS_FAIL;
> +        if (dev_null_redir (stdout) != 1)
> +          retval = STATUS_FAIL;
> +        if (dev_null_redir (stderr) != 1)
> +          retval = STATUS_FAIL;
> +    }
> +
> +    /* Report test result to the parent.  */
> +    close (pipefd[0]);
> +    write (pipefd[1], &retval, 1);
> +    close (pipefd[1]);
> +
> +    _exit (0);
> +  }
> +  else if (pid < 0)
> +    /* Something went wrong.  */
> +    error (EXIT_FAILURE, errno, "cannot fork");
> +
> +  /* This is the parent.  */
> +  if (waitpid (pid, &status, 0) != pid)
> +    error (EXIT_FAILURE, 0, "oops, wrong test program terminated");
> +
> +  if (WTERMSIG (status) != 0)
> +    error (EXIT_FAILURE, 0, "child terminated incorrectly");
> +  status = WEXITSTATUS (status);
> +
> +  /* Read test result from the daemon and report it.  */
> +  close (pipefd[1]);
> +  if (read (pipefd[0], &buf, 1) != 1)
> +    error (EXIT_FAILURE, 0, "failed reading daemon status");
> +  close (pipefd[0]);
> +  TEST_VERIFY_EXIT (buf == STATUS_PASS);
> +}
> +
> +
> +int
> +do_test (void)
> +{
> +  /* Run daemon tests with various parameters.  */
> +  test_daemon (0, 0);
> +  test_daemon (1, 0);
> +  test_daemon (0, 1);
> +  test_daemon (1, 1);
> +
> +  return 0;
> +}
> +
> +#include <support/test-driver.c>