[PATCH] Add --foreground option for nscd

[Carlos O'Donell]

On Wed, May 9, 2012 at 3:26 AM, Andreas Jaeger <aj@suse.de> wrote:
>
> For a better integration of nscd with systemd, we should run nscd not as
> daemon but in the foreground. A new --foreground option should be added.
>
> The following patch is taken from Fedora, I tested it on Linux/x86-64,
>
> Ok to commit?
>
> Andreas
>
> 2012-05-09  Alexandre Oliva  <aoliva@redhat.com>
>
>        * nscd/nscd.c (go_background): Replaced with...
>        (run_in_foreground): ... this.  Document it.
>        (options): Add -F --foreground.
>        (main): Implement it.
>        (parse_opt): Parse it.
>
> diff --git a/nscd/nscd.c b/nscd/nscd.c
> index 9cd7273..77712bf 100644
> --- a/nscd/nscd.c
> +++ b/nscd/nscd.c
> @@ -1,4 +1,4 @@
> -/* Copyright (c) 1998-2011, 2012 Free Software Foundation, Inc.
> +/* Copyright (c) 1998-2012 Free Software Foundation, Inc.
>    This file is part of the GNU C Library.
>    Contributed by Thorsten Kukuk <kukuk@suse.de>, 1998.
>
> @@ -71,7 +71,12 @@ thread_info_t thread_info;
>  int do_shutdown;
>  int disabled_passwd;
>  int disabled_group;
> -int go_background = 1;
> +
> +/* Default is to daemonize.  Set to 1 to run in foreground in
> +   debugging mode, or negative to run in foreground but otherwise
> +   behave like a daemon, i.e., detach from terminal and use
> +   syslog.  */
> +static int run_in_foreground = 0;

Please use an enum. Magic constants are difficult to understand.

Everyone understands:

if (var == NAMED_STATE)

Nobody understands:

if (var <= 0)

... until they go and read the comment which describes two states at 1, and -1.

Am I the only one who doesn't like implied states?

>  static const char *conffile = _PATH_NSCDCONF;
>
> @@ -103,6 +108,8 @@ static const struct argp_option options[] =
>     N_("Read configuration data from NAME") },
>   { "debug", 'd', NULL, 0,
>     N_("Do not fork and display messages on the current tty") },
> +  { "foreground", 'F', NULL, 0,
> +    N_("Do not fork, but otherwise behave like a deamon") },
>   { "nthreads", 't', N_("NUMBER"), 0, N_("Start NUMBER threads") },
>   { "shutdown", 'K', NULL, 0, N_("Shut the server down") },
>   { "statistics", 'g', NULL, 0, N_("Print current configuration statistics") },
> @@ -173,16 +180,22 @@ main (int argc, char **argv)
>   /* Determine page size.  */
>   pagesize_m1 = getpagesize () - 1;
>
> -  /* Behave like a daemon.  */
> -  if (go_background)
> +  if (run_in_foreground <= 0)
>     {
>       int i;
> +      pid_t pid;
>
> -      pid_t pid = fork ();
> -      if (pid == -1)
> -       error (EXIT_FAILURE, errno, _("cannot fork"));
> -      if (pid != 0)
> -       exit (0);
> +      /* Behave like a daemon.  */
> +      if (!run_in_foreground)
> +       {
> +         pid = fork ();
> +         if (pid == -1)
> +           error (EXIT_FAILURE, errno, _("cannot fork"));
> +         if (pid != 0)
> +           exit (0);
> +       }
> +      else
> +       fprintf (stderr, _("further output sent to syslog\n"));
>
>       int nullfd = open (_PATH_DEVNULL, O_RDWR);
>       if (nullfd != -1)
> @@ -233,11 +246,14 @@ main (int argc, char **argv)
>        for (i = min_close_fd; i < getdtablesize (); i++)
>          close (i);
>
> -      pid = fork ();
> -      if (pid == -1)
> -       error (EXIT_FAILURE, errno, _("cannot fork"));
> -      if (pid != 0)
> -       exit (0);
> +      if (!run_in_foreground)
> +       {
> +         pid = fork ();
> +         if (pid == -1)
> +           error (EXIT_FAILURE, errno, _("cannot fork"));
> +         if (pid != 0)
> +           exit (0);
> +       }
>
>       setsid ();
>
> @@ -259,7 +275,7 @@ main (int argc, char **argv)
>       signal (SIGTSTP, SIG_IGN);
>     }
>   else
> -    /* In foreground mode we are not paranoid.  */
> +    /* In debug mode we are not paranoid.  */
>     paranoia = 0;
>
>   signal (SIGINT, termination_handler);
> @@ -308,7 +324,11 @@ parse_opt (int key, char *arg, struct argp_state *state)
>     {
>     case 'd':
>       ++debug_level;
> -      go_background = 0;
> +      run_in_foreground = 1;
> +      break;
> +
> +    case 'F':
> +      run_in_foreground = -1;
>       break;
>
>     case 'f':
>
> --
>  Andreas Jaeger aj@{suse.com,opensuse.org} Twitter/Identica: jaegerandi
>  SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany
>   GF: Jeff Hawn,Jennifer Guild,Felix Imendörffer,HRB16746 (AG Nürnberg)
>    GPG fingerprint = 93A3 365E CE47 B889 DF7F  FED1 389A 563C C272 A126