From: Jason Stephenson <jason@sigio.com>
Date: Thu, 1 Jul 2021 18:28:36 +0000 (-0400)
Subject: Lp 1933984: Improve OpenSRF::Utils::daemonize
X-Git-Url: https://old-git.evergreen-ils.org/?a=commitdiff_plain;h=6fe9f449aab9a28b2e6ef65186c7b23247e0f871;p=working%2FOpenSRF.git

Lp 1933984: Improve OpenSRF::Utils::daemonize

Improve the Perl daemonize function to:

  1. Set the umask to a reasonable, known value (022).

  2. Close all open file descriptors inherited from the parent.

  3. Open /dev/null for standard input, standard output, and standard
  error so that library calls do not clutter the console.

For the logic behind these changes see Chapter 13 of __Advanced
Programming In the UNIX Environment, 3rd Edition__ by W. Richard
Stevens and Stephen A. Rago.

Signed-off-by: Jason Stephenson <jason@sigio.com>
---

diff --git a/src/perl/lib/OpenSRF/Utils.pm b/src/perl/lib/OpenSRF/Utils.pm
index bb6858a..d43a41f 100644
--- a/src/perl/lib/OpenSRF/Utils.pm
+++ b/src/perl/lib/OpenSRF/Utils.pm
@@ -9,6 +9,7 @@ use Exporter;
 use DateTime;
 use DateTime::Format::ISO8601;
 use DateTime::TimeZone;
+use BSD::Resource;
 
 =head1 NAME
 
@@ -426,8 +427,20 @@ sub daemonize {
 		exit 0;
 	} elsif (defined($pid)) {
 		set_psname($PS_NAME);
+		umask(022); # Something reasonable.
 		chdir '/';
 		setsid;
+		my $rlimit = getrlimit(RLIMIT_NOFILE);
+		$rlimit = ($rlimit == RLIM_INFINITY) ? 1024 : $rlimit;
+		for (my $i = 0; $i < $rlimit; $i++) {
+			POSIX::close($i);
+		}
+		# Direct STDIN, STDOUT, and STDERR to /dev/null to avoid
+		# console pollution
+		my ($fd0, $fd1, $fd2);
+		$fd0 = POSIX::open("/dev/null", O_RDWR);
+		$fd1 = dup($fd0);
+		$fd2 = dup($fd0);
 		return $$;
 	}
 }