Quick parse Apache httpd error log

[user@logs]# cat error_log | cut -d " " -f 11,13,14 | sort -n | uniq -c | sort -r
    728 script not found
    101 AH01276: serve directory
     57 AH02811: not found
     25 PHP  Undefined
      3 server does NOT
      3 PHP  session_start():
      1 slotmem mod_heartmonitor
      1 mpm (prefork.c) is
      1 line: -D FOREGROUND'
      1 () PHP/7.3.11 configured
     
      ---

So most often error message is "script not found". A concrete example of error that needs to be addressed is the below:
[client 173.212.201.253:34544] script '/var/www/html/sitedomain/prod/wp-login.php' not found or unable to stat, referer: http://sitedomain.com/wp-login.php

This is to be tackled in another article :)

Fix PHP Notice: Undefined index: HTTP_HOST in php on line

It might be that $_SERVER['HTTP_HOST'] is undefined.

To check this, better to verify using isset before instantiating it:


$link .= "http://";

if (isset($_SERVER['HTTP_HOST'])) {
        $link .= $_SERVER['HTTP_HOST'];
}

Script to check when specific SSL website certificate is to expire

#!/bin/bash
expire=$(echo | openssl s_client -servername easybiny.com -connect easybiny.com:443 2>/dev/null | openssl x509 -noout -dates | awk 'BEGIN{FS="After="} {print $2}')

date_today=$(date -d "now" +%s)
date_expire=$(date -d "$expire" +%s)
result=$(( (date_expire - date_today) / 86400 ))-days
echo $result


Running the above will prodice the desired output:

[root@x.x.x.x monitoring]# ./check-easybiny-certificate.sh
75-days

SSL Certificate - Get expiration date from shell with openssl

Very simple, just run the following command:

[root@ip-172-31-39-55 monitoring]# echo | openssl s_client -servername www.easybiny.com -connect www.easybiny.com:443 2>/dev/null | openssl x509 -noout -dates
 
notBefore=Mar 28 13:43:20 2020 GMT
notAfter=Jun 26 13:43:20 2020 GMT

Fixed: Where PHP sessions are stored?

This is setup using the following parameter:

session.save_path  

By default, at least in PHP 7.3, this is commented in php.ini:
;session.save_path = "/tmp"

It means default location is the following one:
/var/lib/php/session

In there you'll get files like the below:
[root@ip-172-31-39-55 session]# ls -l
-rw------- 1 apache apache 71 Apr 18 18:31 sess_0a2bbj0u9nsf9gh5vbddte855e
-rw------- 1 apache apache  0 Apr 18 11:13 sess_0uttil3jnenoos2kcf6t45gqj5
-rw------- 1 apache apache  0 Apr 17 15:30 sess_1f57jnsc28gj06km301b4von1a
-rw------- 1 apache apache  0 Apr 18 10:39 sess_2ips2j6djo8fst8lm4lq9q7l6n
-rw------- 1 apache apache  0 Apr 18 09:23 sess_32ta8talaki4a7umbuq6ivfqdi


If you also have have session parameters ($_SESSION['parameter']), you shall see those in file:
cat sess_vssets4hr5b1h89ad7k93q3rhl
loggedin|b:1;name|s:1:"D";id|i:6;

PHP 7.3 - Find php.ini file

Simply run this command:

php -i | grep "Loaded Configuration File"

In my case it found the file here:

[root@x.x.x.x etc]# php -i | grep "Loaded Configuration File"
Loaded Configuration File => /etc/php.ini

Crontab -e log history on Amazon Linux 2

This is located here:

/var/log/cron

Example of usage:

tail -500f /var/log/cron

You shall find your scripts from crontab -e being run:

Apr 17 22:43:01 ip-172-31-39-55 CROND[1407]: (root) CMD (sh /home/dtech/monitoring/check-daily-requests.sh)
Apr 17 22:43:01 ip-172-31-39-55 CROND[1408]: (root) CMD (sh /home/dtech/monitoring/check-cpu)

Splunk: Split URL Path by removing query parameters

If you have something like the below:

/easybiny.stockprice.json?dt=123213

and want only to get the path without query string:
/easybiny.stockprice.json

Then easy way is to do this in the Splunk search statement:

eval url=mvindex(split(request, "?"), 0) | table request,url

MariaDB/MySQL show privilegies for DB User

MariaDB [xxxx]> show grants for 'xxxx'@"localhost";
+------------------------------------------------------------------------+
|Grants for xxxx@localhost                                              |
+------------------------------------------------------------------------+
| GRANT USAGE ON *.* TO 'xxxx'@'localhost' IDENTIFIED BY PASSWORD '*xxx'
| GRANT SELECT, INSERT ON `dtech`.`bins` TO 'xxxx'@'localhost'          
+------------------------------------------------------------------------+

Fix "PHP Fatal error: Uncaught Error: Call to a member function bind_param() on bool in"

First of all, please make sure you have proper verbose error to identify root cause:


if ($stmt = $conn->prepare("SELECT id, password FROM accounts WHERE email = ?")) {
        $stmt->bind_param("s", $_POST['username']);
        $stmt->execute();
        $stmt->store_result();
....

else{
$error = $conn->errno . ' ' . $conn->error;
echo $error;
}

Once this in place, I can get the exact error message in browser:

1142 SELECT command denied to user 'xxxx'@'localhost' for table 'accounts'DB error

So my xxxx user does not have proper access. 

This is easily to be fixed by running the following command:

GRANT SELECT ON db.accounts TO xxxx@'localhost';

Redirect www subdomain to "apex" like subdomain

First, please always use https and proper certificate.

Secondly, add the following rule to your virtual host:

...

RewriteEngine on
RewriteCond %{SERVER_NAME} =www.stage.easybiny.com
RewriteRule ^ https://stage.easybiny.com%{REQUEST_URI} [END,NE,R=permanent]

...

Note: In this example, stage.easybiny.com is the "apex" like subdomain.