From bd39076a1ca11987f1cbef34823ab5d09b082550 Mon Sep 17 00:00:00 2001
From: Raphael Hertzog <hertzog@debian.org>
Date: Fri, 15 Feb 2008 15:45:10 +0100
Subject: [PATCH] Dpkg::IPC: new module to handle common IPC

* scripts/Dpkg/IPC.pm: New module handling IPC. Started with
fork_and_exec() and wait_child(). STDIN/STDOUT of the child
process can be easily redirected to a file or any other
filehandle.
---
 debian/dpkg-dev.install |  1 +
 scripts/Dpkg/IPC.pm     | 80 +++++++++++++++++++++++++++++++++++++++++
 scripts/Makefile.am     |  1 +
 scripts/po/POTFILES.in  |  1 +
 4 files changed, 83 insertions(+)
 create mode 100644 scripts/Dpkg/IPC.pm

diff --git a/debian/dpkg-dev.install b/debian/dpkg-dev.install
index b6eeb462..db4d00d6 100644
--- a/debian/dpkg-dev.install
+++ b/debian/dpkg-dev.install
@@ -71,6 +71,7 @@ usr/share/perl5/Dpkg/Changelog/Debian.pm
 usr/share/perl5/Dpkg/Deps.pm
 usr/share/perl5/Dpkg/ErrorHandling.pm
 usr/share/perl5/Dpkg/Fields.pm
+usr/share/perl5/Dpkg/IPC.pm
 usr/share/perl5/Dpkg/Path.pm
 usr/share/perl5/Dpkg/Shlibs
 usr/share/perl5/Dpkg/Shlibs.pm
diff --git a/scripts/Dpkg/IPC.pm b/scripts/Dpkg/IPC.pm
new file mode 100644
index 00000000..090ecc97
--- /dev/null
+++ b/scripts/Dpkg/IPC.pm
@@ -0,0 +1,80 @@
+# Copyright 2008 Raphaël Hertzog <hertzog@debian.org>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+
+# This program 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 General Public License for more details.
+
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+package Dpkg::IPC;
+
+use strict;
+use warnings;
+
+use Dpkg::ErrorHandling qw(error syserr subprocerr);
+use Dpkg::Gettext;
+
+use Exporter;
+our @ISA = qw(Exporter);
+our @EXPORT = qw(fork_and_exec wait_child);
+
+sub fork_and_exec {
+    my (%opts) = @_;
+    error("exec parameter is mandatory in fork_and_exec()") unless $opts{"exec"};
+    my @prog;
+    if (ref($opts{"exec"}) =~ /ARRAY/) {
+	push @prog, @{$opts{"exec"}};
+    } elsif (not ref($opts{"exec"})) {
+	push @prog, $opts{"exec"};
+    } else {
+	error(_g("invalid exec parameter in fork_and_exec()"));
+    }
+    # Fork and exec
+    my $pid = fork();
+    syserr(_g("fork for %s"), "@prog") unless defined $pid;
+    if (not $pid) {
+	# Redirect STDIN if needed
+	if ($opts{"from_file"}) {
+	    open(STDIN, "<", $opts{"from_file"}) ||
+		syserr(_g("cannot open %s"), $opts{"from_file"});
+	} elsif ($opts{"from_handle"}) {
+	    open(STDIN, "<&", $opts{"from_handle"}) || syserr(_g("reopen stdin"));
+	    close($opts{"from_handle"}); # has been duped, can be closed
+	}
+	# Redirect STDOUT if needed
+	if ($opts{"to_file"}) {
+	    open(STDOUT, ">", $opts{"to_file"}) ||
+		syserr(_g("cannot write %s"), $opts{"to_file"});
+	} elsif ($opts{"to_handle"}) {
+	    open(STDOUT, ">&", $opts{"to_handle"}) || syserr(_g("reopen stdout"));
+	    close($opts{"to_handle"}); # has been duped, can be closed
+	}
+	# Close some inherited filehandles
+        close($_) foreach (@{$opts{"close_in_child"}});
+	# Execute the program
+        exec(@prog) or syserr(_g("exec %s"), "@prog");
+    }
+    # Close handle that we can't use any more
+    close($opts{"from_handle"}) if exists $opts{"from_handle"};
+    close($opts{"to_handle"}) if exists $opts{"to_handle"};
+
+    return $pid;
+}
+
+sub wait_child {
+    my ($pid, %opts) = @_;
+    $opts{"cmdline"} ||= _g("child process");
+    error(_g("no PID set, cannot wait end of process")) unless $pid;
+    $pid == waitpid($pid, 0) or syserr(_g("wait for %s"), $opts{"cmdline"});
+    subprocerr($opts{"cmdline"}) if $?;
+}
+
+1;
diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index 8d91d9df..4d79817b 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -95,6 +95,7 @@ nobase_dist_perllib_DATA = \
 	Dpkg/ErrorHandling.pm \
 	Dpkg/Fields.pm \
 	Dpkg/Gettext.pm \
+	Dpkg/IPC.pm \
 	Dpkg/Path.pm \
 	Dpkg/Shlibs.pm \
 	Dpkg/Shlibs/Objdump.pm \
diff --git a/scripts/po/POTFILES.in b/scripts/po/POTFILES.in
index 4a14b35f..240ff28f 100644
--- a/scripts/po/POTFILES.in
+++ b/scripts/po/POTFILES.in
@@ -22,6 +22,7 @@ scripts/Dpkg/Control.pm
 scripts/Dpkg/Deps.pm
 scripts/Dpkg/ErrorHandling.pm
 scripts/Dpkg/Fields.pm
+scripts/Dpkg/IPC.pm
 scripts/Dpkg/Shlibs.pm
 scripts/Dpkg/Shlibs/Objdump.pm
 scripts/Dpkg/Shlibs/SymbolFile.pm
-- 
2.39.5