#!/usr/bin/perl --        -*-CPerl-*-

use strict;

$::Prog = "ifup-tryall";

##  @ifs = ifs_up()
##    -- Returns list of eth/wlan interfaces currently up
sub ifs_up
{
    my (@lines);

    ##  See if any eth interfaces are already up
    @lines = `/bin/netstat -i`;
    @lines = (map (($_ =~ /^(eth\d+)\s+/) ?  $1 : (), @lines),
	      map (($_ =~ /^(wlan\d+)\s+/) ?  $1 : (), @lines));
    return (@lines);
};

sub main
{
    my ($pid, $if, @ifs, @lines);

    ($> == 0) || die ("Must run $::Prog as root\n");

    ##  Detach & fork
    setpgrp() || die ("$::Prog: Cannot setpgrp: $!");
    defined ($pid = fork())
      || die ("$::Prog: cannot fork: $!");
    $pid && exit(0);  ##  I am the parent

    ##  Redirect output to log file
    open (STDIN, "/dev/null");
    open (STDOUT, ">>/var/log/$::Prog")
      || die ("cannot open STDOUT to /var/log/$::Prog: $!");
    select (STDOUT); $| = 1;
    open (STDERR, ">&STDOUT")
      || die ("cannot open STDERR to STDOUT (dup): $!");
    select (STDERR); $| = 1;
    select (STDOUT);

    @ifs = ifs_up();
    if (scalar (@ifs))
    {
	##  One or more interfaces are already up
	print ::STDOUT ($_ = localtime, " interfaces already up: ",
			join (" ", @ifs), "\n");
	return;
    };

    ##  Get configured interfaces
    @ifs = </etc/sysconfig/network-scripts/ifcfg-*>;
    @ifs = (map (($_ =~ /(eth\d+)$/) ?  $1 : (), @ifs),
	    map (($_ =~ /(wlan\d+)$/) ?  $1 : (), @ifs));
    if (! scalar (@ifs))
    {
	print ::STDOUT ($_ = localtime, " No configured interfaces found\n");
	return;
    };

    ##  Bring one up
    foreach $if (@ifs)
    {
	print ::STDOUT ($_ = localtime, " Trying to start $if\n");
	system ("/sbin/ifup", $if, "up");
	if (scalar (ifs_up()))
	{
	    print ::STDOUT ($_ = localtime, " Interface is now up\n");
	    return;
	};
    };

    print ::STDOUT ($_ = localtime,
		    " Cannot bring up any interfaces, exiting\n");
};

main();