Accessing X Display through Apache - php

I am trying to send keypresses to a Raspberry Pi running Raspdbian from from a web page hosted on an Apache server at /var/www.
I'm using xdotool, which can send keypresses using commands like this:
xdotool key C
I made a python script xdotool.py that sends a few keypresses like that:
#!/usr/bin/env python
import os
print 'sending HI'
os.system("export DISPLAY=:0")
os.system("xdotool key H")
os.system("xdotool key I")
I am SSH'd into the Raspberry as user Pi, and running this script from terminal works fine and sends the keystrokes "HI" to the Raspberry.
However, I want to be able to do this through a web page. I've made a php-script that runs python scripts and displays the terminal output in the browser, but it does not work with the xdotool.py script. I have given the script permission to be viewed/changed/executed by all users.
I've also changed the Apache settings in /etc/apache2/envvars and changed the user from www-data to pi. The user pi should have all necessary permissions.
The script does run, and "sending HI" is displayed in the browser. But it doesn't send the keystrokes. The error I get from error.log is this:
Error: Can't open display: (null)
Failed creating new xdo instance
Any ideas how I can accomplish this? If there's a way to give everyone permission to do everything, that wouldn't be a problem seeing that this server will only run on a local network with no internet access.

Related

Serial port access denied

I am running an Apache web server on a Raspberry Pi. I have some Python code which executes in the index.php file as follows:
<?php
system("python /home/pi/python/foobar.py")
?>
The python script opens a serial port, like so:
ser = serial.Serial()
ser.port = "/dev/ttyUSB0"
When I run the python script from the command line on the Raspberry Pi, it works perfectly. However, when I browse the site on another computer, I get this error message:
[Errno 13] Permission denied: '/dev/ttyUSB0'
I have done some research and found that most people who run into this error do so because the user doesn't belong to the dialout group. When using the Raspberry Pi, I do belong to it, and I assume that on another computer, I don't.
In summary, how do I get permission to access a serial port on a Raspberry Pi server?

PHP exec running in background with Windows & Apache but not Nginx

I have tried both Apache/PHP and Nginx/PHP with nearly the same configuration.
I am running this script:
<?php
exec("calc.exe");
?>
In Apache/PHP, calc.exe is not opened but is found running as a background process.
In Nginx/PHP, calc.exe is opened properly.
I would like to use Apache/PHP to open calc.exe properly.
Exec has no functionality with display, it will spawn processes and such under a different user (thus no affect on the current logged in user)
Scenario; your logged in as User1
On php do the following;
Exec("whoami");
You will see a different user which apache/web service is running as

Raspberry Pi unable to execute script by PHP

I'm playing with Raspberry Pi and anm Arduino shield in order to run a script via Apache/PHP. This script simple blink a LED. I have already tested the script via shell and it works fine, with the command
/root/arduPi/blink_test
I'm able to see my LED blinking. So I made the same thing via Apache PHP with this short PHP script
<?php
if(isset($_GET['cmd'])){
echo '/root/arduPi/'.$_GET['cmd'];
exec('/root/arduPi/'.$_GET['cmd']);
}
?>
but nothing happen and no error has been displayed.
I tested the PHP code with
<?php
phpinfo();
?>
and it's fine. How can I fix this problem?
I had the same issue a while back it was because Apache does not have permission to access certain devices on the Pi. I fixed this by getting rid of the need to be root to access these devices. HERE Is my post about this same issue the fix was to setup sudo as passwordless.
THIS is what I used to accomplish setting up sudo as passwordless. You should then be able to execute the script as follows exec('sudo /root/arduPi/'.$_GET['cmd']);

How can I launch a local Application on OSX from php running MAMP?

I'm running a bunch of local Kiosks on mac mini's and have been using dropbox to keep all the files in sync. However - the dropbox updates have been sketchy as of late because of the firewall settings where these things are. A workaround I have found is by having dropbox quit and restart periodically to force it to update.
My question is - since all of these are running php applications on MAMP - is there a way to launch a local app from php? I'm able to kill dropbox by doing something like this:
$killit = killall -KILL Dropbox;
But it doesn't work the same to restart it. I've tried doing this:
$start_dbox = open /Applications/Dropbox.app;
To no avail. Is there a better way to automate this process of shutting down and reopening a local application?
I've had similar problems trying to control software remotely. The 'open' command must be executed either as the currently logged in console user, or from a terminal owned by the console (e.g. Terminal.app).
If you change your PHP to redirect STDERR, you should see the error that 'open' is returning:
$start_dbox = "open /Applications/Dropbox.app 2>&1";
The following text should then be returned from the system call:
LSOpenURLsWithRole() failed with error -10810 for the file /Applications/Dropbox.app.
One workaround I've used in the past is to create a lock file somewhere in the filesystem, which your PHP script can write to and your console user can read. Then, you can create a cron that runs as the console user and periodically checks the lock file to see if it needs to restart Dropbox.
I was actually able to solve this by creating a shell script with the following:
#!/bin/sh
export DYLD_LIBRARY_PATH=""
osascript -e 'tell application "Dropbox" to activate'
Saved it as start_db.sh and dropped it in my root apache directory (so there was no permissions problem for that user).
Then in my php file I was able to do:
$start_dbox = exec('/full/path/to/start_db.sh');
Worked like a charm. Dropbox now quits and restarts with no issues.

Server side script for launching application

I have been trying unsuccessfully so far to write a php script that will run when a page is opened and that will launch metasploit!
I ve tried shell_exec and exec and all the other alternatives but although I can get it to do simple things (i.e. ls, cds etc) if I try msfconsole it doesnt do anything!
I have also tried a different script that launches firefox and again nothing happens!
Now i know that php runs on the server and I m not expecting to see a console or firefox opening in the clients machine! Instead in order to check if it works I am trying to echo out the output of the shell_exec!But anyway since im hosting the files on my machine (i.e. this is the server and a VM is the client) if it could actually launch firefox i should be able to see the app opening here in the same way as by just doing this from the command line!
What am I missing?
Is there any other way to do this?(i.e. Launch metasploit everytime a user opens up my page)
NOTE: I've tried specifying the full path for msfconsole but that didnt work either!
Heres what I have so far:
$output = shell_exec('/opt/local/libexec/metasploit3/msfconsole;show');
echo "<pre>$output</pre>";
The ";show" bit was used in order to actually make it run something and print some stuff but didnt make any difference!
When you run a gui application from the command prompt in a X window system, it will use the default display. When you run it using php which is embedded in apache webserver, the program may not know where to display the gui application.
there are 2 things to make this work.
The program that executes the gui application must have permission to use display
you need to tell the program which display to use.
I used the following in my php script
<?php
$cmd = `export DISPLAY=:0; gedit`;
shell_exec($cmd);
?>
and ran the script from terminal using php -f test.php
I got the gedit up and running.
You can test the same with the script in apache too.
Please add apache user with privileges to access display server
update: I just added the following in /etc/apache2/apache2.conf (I am using ubuntu)
User poomalai
Group poomalai
and restarted the web server
sudo service apache2 restart
now I accessed localhost/test.php
and Presto!! I got the gedit :)
Hope this helps

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