php warning fclose() expects parameter 1 to be resource boolean given - php

Question

I use newrelic to keep track of anything on my website and I always get this error:
Error message: E_WARNING: fclose() expects parameter 1 to be resource, boolean given
Stack trace: in fclose called at /etc/snmp/bfd-stats.php (68)
This is how /etc/snmp/bfd-stats.php looks like
<?php
$a = 0;
$ptr = 0;
$any = 0;
$mx = 0;
$ns = 0;
$cname = 0;
$soa = 0;
$srv = 0;
$aaaa = 0;
$txt = 0;
$total = 0;
if(file_exists('/etc/snmp/bfd-log-pos.stat')) {
$lfh = fopen('/etc/snmp/bfd-log-pos.stat','r');
$string = fread($lfh,2087);
$res = explode(',',$string);
fclose($lfh);
}
else {
$res = array();
$res[0] = 0;
$res[1] = 0;
}
if(file_exists("/var/log/bfd_log.1")) {
$stats = stat('/var/log/bfd_log.1');
if($stats[10] > $res[0]) {
$res[0] = 0;
$res[1] = 0;
}
}
$fh = fopen('/var/log/bfd_log', 'r');
fseek($fh,$res[1]);
$blocks = 0;
if(!$fh) {
echo "Error! Couldn't open the file.";
} else {
while (!feof($fh)) {
$data = fgets($fh);
if(preg_match('/executed\sban/',$data)) {
$blocks++;
}
}
}
$lfh = fopen('/etc/snmp/bfd-log-pos.stat','w');
$timestamp = time();
$pos = ftell($fh);
fwrite($lfh,"$timestamp,$pos");
fclose($lfh);
if(!fclose($fh)) {
echo "Error! Couldn't close the file.";
}
print("bfd_blocks\n$blocks");
?>
On line 40: $fh = fopen('/var/log/bfd_log', 'r'); I looked at the directory /var/log and there is no file called bfd_log, I dont know if I have to create it by myself or it is automatically created.
Can anyone help me on fixing this error, Thanks in advance.

Answer 1

The error indicates that you are trying to pass a variable with a boolean value (true/false) to a function that needs a resource instead of a boolean value.
Please make sure that before you use resources from variables, the function that returns the resource has not run into trouble. Only on success perform the other functions that use this resource/variable.
$fh = fopen('/var/log/bfd_log', 'r');
// check fh before other functions use this variable
if (!$fh) {
echo "Error! Couldn't open the file.";
} else {
// perform task with resource $fh
fseek($fh, $res[1]);
[...]
$lfh = fopen('/etc/snmp/bfd-log-pos.stat', 'w');
// check before other code block is executed and use this variable
if( $lfh )
{
// perform task with resource $lfh
$pos = ftell($fh);
fwrite($lfh, "$timestamp,$pos");
fclose($lfh);
fclose($fh);
[...]
} else {
// lfh error
}
}
If you always check before using variables, you won't run into this error anymore.

Answer 2

I wrestled with this problem and could not find the answer until I separated my write check (put it first) from the actual file write code. So before I would open the file fopen/fwrite then do the is_writable check and then do the fclose and i would get this error.
To resolve I moved the is_writable and variable declaration before the fopen/fwrite and the error went away. Shown below (former php code position shown in comments) The first comment did help me realize this... Thank you.
$myfile = "/var/www/html/newfile.txt";
if (is_writable($myfile)) {
echo "The file is writable";
}
else {
echo "The file is not writable";
}
$txt = "$name, $email, $command, $searchtype, $keyword \n";
$myfile = fopen('/var/www/html/newfile.txt', 'w') or die("Unable to open file!");
fwrite($myfile, $txt);
// $myfile = "/var/www/html/newfile.txt";
// if (is_writable($myfile)) {
// echo "The file is writable";
// }
// else {
// echo "The file is not writable";
// }
fclose($myfile);

Answer 3

Try
$fh = fopen('/var/log/bfd_log', 'a+');
a+ mode will create the file if it does not exists