#!/usr/bin/perl -w
use English;
require Mysql;

#
# A library of useful DB stuff. Mostly things that get done a lot.
# Saves typing.
#

#
# Configure variables
#
my $TB		= "@prefix@";
my $DBNAME	= "@TBDBNAME@";
my $TBOPS       = "@TBOPSEMAIL@";

#
# Set up for querying the database.
# 
my $DB = Mysql->connect("localhost", $DBNAME, "script", "none");

#
# Record last DB error string.
#
my $DBErrorString = "";

#
# Test admin status. Optional argument is the UID to test. If not provided,
# then test the current UID.
#
# usage: TBAdmin([int uid]);
#        returns 1 if an admin type.
#        returns 0 if a mere user.
# 
sub TBAdmin(;$)
{
    my($uid) = @_;

    if (!defined($uid)) {
	$uid = $UID;
    }

    my ($name) = getpwuid($uid)
	or die "$uid not in passwd file\n";

    my $query_result =
	DBquery("select admin from users where uid='$name'");

    my @row = $query_result->fetchrow_array();
    if ($row[0] == 1) {
	return 1;
    }
    return 0;
}

#
# Check access permission to a list of nodes. First argument is a *reference* to
# a single node, or a list of nodes. Second argument is optional uid, defaults
# to the current uid.
#
# usage: NodeAccessCheck(array or scalar \@nodelist, [int uid])
#        returns 1 if the uid is allowed to muck with all the nodes.
#        returns 0 if the uid is not allowed to muck with at least one of the nodes.
#
sub NodeAccessCheck($;$)
{
    my($list, $uid) = @_;
    my(@nodelist);

    if (!defined($uid)) {
	$uid = $UID;
    }

    if (ref($list) eq "ARRAY") {
	@nodelist = @$list;
    }
    elsif (ref($list) eq "SCALAR") {
	@nodelist = ($$list);
    }

    if (!defined(@nodelist) ||
	scalar(@nodelist) == 0) {
	die("NodeAccessCheck:\n".
	    "  First parameter should be a reference to a node (scalar), ".
	    "or a list of nodes!\n");
    }

    #
    # Admin types can do anything to any node. So can Root.
    #
    if ($uid == 0 || TBAdmin($uid)) {
	return 1;
    }

    my ($name) = getpwuid($uid)
	or die "$uid not in passwd file\n";

    #
    # Check to make sure that mere user is allowed to muck with nodes.
    #
    foreach my $node (@$nodelist) {
	my $query_result =
	    DBquery("select reserved.node_id from reserved ".
		    "left join proj_memb on ".
		    "reserved.pid=proj_memb.pid and reserved.node_id='$node' ".
		    "where proj_memb.uid='$name'");

	if ($query_result == 0 ||
	    $query_result->numrows == 0) {
	    return 0;
	}
    }
    return 1;
}

#
# Check project membership. First argument is the project to check.
# Second argument is optional uid, defaults to the current uid.
#
# usage: ProjMember(char *pid, [int uid])
#        returns 1 if the uid is a member of pid.
#        returns 0 if the uid is not a member of pid.
# 
sub ProjMember($;$)
{
    my($pid, $uid) = @_;

    if (!defined($uid)) {
	$uid = $UID;
    }

    my ($name) = getpwuid($uid)
	or die "$uid not in passwd file\n";

    my $query_result =
	DBquery("select * from proj_memb where uid='$name' and pid='$pid'");

    if ($query_result == 0 ||
	$query_result->numrows == 0) {
	return 0;
    }
    return 1;
}

#
# Issue a DB query. Argument is a string. Returns the actual query object, so
# it is up to the caller to test it. I would not for one moment view this
# as encapsulation of the DB interface. I'm just tired of typing the same
# silly stuff over and over. 
# 
# usage: DBQuery(char *str)
#        returns the query object result.
#
# Sets $DBErrorString is case of error; saving the original query string and
# the error string from the DB module. Use DBFatal (below) to print/email
# that string, and then exit.
#
sub DBQuery($)
{
    my($query) = $_[0];
    my($result);

    $result = $DB->query($query);

    if (! $result) {
	$DBErrorString =
	    "  Query: $query\n".
	    "  Error: " . $DB->errstr . "\n";
    }
    return $result;
}

#
# Same as above, but die on error. 
# 
sub DBQueryFatal($)
{
    my($query) = $_[0];
    my($result);

    $result = DBQuery($query);

    if (! $result) {
	DBFatal("DB Query failed");
    }
    return $result;
}

#
# Die and send email after a failed DB query. First argument is the error
# message to display. The contents of $DBErrorString is also printed.
# 
# usage: DBFatal(char *message)
#
sub DBFatal($)
{
    my($message) = $_[0];
    my($text, $progname);

    #
    # Must taint check $PROGRAM_NAME cause it comes from outside.
    #
    if ($PROGRAM_NAME =~ /^([-\w.\/]+)$/) {
	$progname = $1;
    }
    else {
	$progname = "Tainted";
    }

    $text = "In TB script: $progname\n\n $message\n" . "$DBErrorString";

    print STDERR "$text\n";

    system("echo \"$text\" | /usr/bin/mail ".
	   "-s 'TESTBED: DBFatal - $message' \"$TBOPS\"");

    exit(-1);
}

1;