I am having an issue using the PHP function shell_exec().
I have an application which I can run from the linux command line perfectly fine. The application takes several hours to run, so I am trying to spawn a new instance using shell_exec() to manage better. However, when I run the exact same command (which works on the command line) through shell_exec(), it returns an empty string, and it doesn't look like any new processes were started. Plus it completes almost instantly. shell_exec() is suppose to wait until the command has finished correct?
I have also tried variations of exec() with the same outcome.
Does anyone have any idea what could be going on here?
There are no symbolic links or anything funky in the command: just the path to the application and a few command line parametes.
Some thing with you env
See output of env from cli (command line interface) and php script
Also see what your shell interpreter?
And does script and cli application runs from one user?
If so, se option safe_mode
Make sure the user apache is running on (probably www-data) has access to the files and that they are executable (ls -la). A simple chmod 777 [filename] would fix that.
By default PHP will timeout after 30 sec. You can disable the limit like this:
<?php
set_time_limit(0);
?>
Edit:
Also consider this: http://www.rabbitmq.com/
Related
I'm controlling my home automation with a Raspberry Pi and webserver. I use this line to turn on my lights (sending an RC signal to wireless power socket).
exec("sudo ./../../../home/pi/wiringPi/examples/lights/action 63 A on");
This is working when the script is ran by a cron job, but when I manually want to execute this command (using a php form and buttons), it does not work. I tried adding $output, $return); and checking $return, and that confirms the exec() function is not executed. However, when I use something like exec("whoami");, the script is executed.
What is it about my command that makes it work only in cron jobs? I had this working once, don't know what happened. Manually sending the command via ssh in the terminal is working normally.
Fix permissions on this command and run it without sudo (for ubuntu default php user is www-data, for suse wwwrun, ...).
Check the path also. I recommend absolute paths.
This is really simple but I cannot get it to work at all. Spent many hours and I've always give up. I created php script called copy.php and it should call a python script called copy.py.
I want to execute a command line like this
<?php exec('/var/www/html/copy.py'); ?>
Really simple.
Why cannot I get the python script executed from php exec()? The function inside python script is to get a copy of error_log from a different directory (outside of Apache) into html directory.
If I run that from a terminal
> php copy.php
It did execute the function and made a copy. Why is that the web browser isn't doing it?
Let me simplify this:
why cannot exec("cp /var/log/httpd/error_log /var/www/html/path/to/php/script") work?
it works fine if I type it in terminal but not when run in a browser.
As others have alluded to, the difference is probably permissions. When you run a command from the command line, you're generally not the same users as your apache script is running as.
Put another way, if from the command line you type whoami, you'll probably get whatever name your user account is.
The echo exec('whoami'); from within php shows who the script is running as, which is Apache.
So, whatever command you're trying to run from your web server isn't available to run as the Apache user. You mentioned you've been able to have exec("python /usr/diskpurge/script.py") work, but not to have exec('/var/www/html/copy.py') doesn't. This is due to in one instance you're running python, in the other you're trying to execute your copy.py script. If copy.py doesn't have execute permissions for the Apache user, you're not going to be able to run it from the browser.
Perhaps different settings apply for the Apache environment versus the command line.
Use error_reporting(E_ALL); and ini_set('display_errors', true) to see what errosr may come up.
It is possible that the Apache environment is prohibited from using exec or the fact that Apache runs under a different user that does not have execute rights on the python script.
sounds like a permission error. Check if your server is running with sufficient rights.
echo exec('whoami');
Set your error reporting to report all:
ini_set('display_errors', true);
error_reporting(E_ALL);
and check for errors..
If your whoami returns a user which is not a member of the SU family (linux) or administration (windows) then resite your permissions..
Linux:
Assign the user returned by whoami correct permissions to run python scripts.. Do not allow the resulted username to run as root with total administration powers.. This is a big no no
The only reason its not working is because you didn't set the write permissions!
Do:
sudo nano /etc/sudoers
And then put the following:
www-data ALL=(root) NOPASSWD:ALL
it's a bit complicated. :-) I have a website written in PHP that needs to call an external program written in .NET, running under Mono. It calls the program with:
/path/mono /path/executable arguments...
as per usual (I also tried to put this into a bash script and call the script itself from PHP).
As far as I can tell, everything is set up as required. Mono itself running all right, executable (or script) with executable rights, owners are all right. The correct setup can also be ascertained from the fact that if I issue the command line above (or call the script mentioned) from a command line on the server (Debian Lenny), everything works perfectly, my executable is executed without error.
But, if PHP calls the same (using exec(), system() or any other variant), I immediately get an exit code of 6 from Mono and my executable is not run at all (in order to test it, I use a "Hello World" executable that does nothing but emits a single output line and returns 0). Compiled without any additional dependency, just a real "Hello Word". It's absolutely sure that this program doesn't return the exit code 6, it must come from Mono but I couldn't find it documented anywhere.
I can call anything else from PHP, so it's not safe mode or any similar restriction that would keep me from executing external programs from PHP.
Thanks for any idea...
Try to execute mono from the command line but with the user running the webserver (www-data or apache).
ej.
#su apache
$/path/to/mono /path/to/program.exe
The common problems that I have using exec is a different environment variables (look if is bash or sh what apache is using), permissions to the user/group of apache, etc.
I have a program that returns a comma-separated string of numbers after doing some background processing. I intended to run this in symfony using shell_exec; however, all I get is NULL (revealed through a var_dump(). I tried the following debugging steps.
I ran the file (it's a PHP class) through a command-line lime unit test in Symfony - it works and gives the correct result there.
Just to check, I tried a simple command ls -l at the same place to see whether I would get anything. Again, I had the same problem - the var_dump in the browser showed NULL, but it worked through the command line.
What could be the problem? Are there restrictions on running shell_exec() in a browser?
EDIT: Just to clarify, shell_exec() commands work when I run them as standalone php scripts on the web server (for example, by putting them in my document root. They don't seem to be working under the symfony framework, for some reason.
I finally solved it, and it turned out to be something quite simple, and quite unrelated.
The shell command I was running was in this format: face_query -D args. I didn't realize that Apache would be executing PHP as user www-data and thus the program face_query wouldn't be in the PATH (the directory is actually ~/bin). Changing the program name to the full path of the program solved it.
I also gather from this that only commands which www-data has permission to execute can be run. In this case, www-data is in the same group as my user, but it might be a problem otherwise.
Have you tried using exec? Or one of the other variants. I am never sure of which one to use and always lump with exec.
http://uk.php.net/manual/en/function.exec.php
Is your web server running php in safe mode?
Note: This function is disabled when PHP is running in safe mode.
From: http://php.net/manual/en/function.shell-exec.php
I have a Ruby script that's being used to do some API calls/screen scraping, but our main app is in PHP. Our PHP app is using shell_exec() to call the Ruby script.
The ruby script works great when called from the command line–but it will randomly exits early when called via PHP's shell exec.
Here's an example of the Ruby script:
#!/usr/bin/env ruby
require 'rubygems'
require 'mysql'
require 'net/http'
require 'open-uri'
require 'uri'
require 'cgi'
require 'fileutils'
# Bunch of code here ... works fine
somePath = 'http://foo.com/bar.php'
# Seems to always exit when I do a Net::HTTP or open-uri call
post = Net::HTTP.post_form(URI.parse(somePath),{'id'=>ID,'q'=>'some query'})
data = post.body
# OR
data = open(somePath).read
# More code here ...
So, all I can deduce so far is that it's always exiting when I try to grab/read an external URL via net/http or open-uri calls. The pages I'm grabbing can accept POST or GET requests, but it seems to be exiting either way.
I'm outputting the results with PHP after the shell_exec call, but there are no error messages or exits. I do have messages being output by my Ruby script with "puts ...." here and there. Could that be a problem (I'm thinking 'no' because it doesn't exit with earlier puts messages)?
Again, it works fine when called from the shell. It's almost like the shell_exec call isn't waiting for the net/http call to finish.
Any ideas?
I'm not sure on this, but given your explanation, which sounds plausible, have you looked at all at proc_open:
http://us3.php.net/proc_open
Ruby's open-uri requires tempfile, so I'm guessing there's a file ownership conflict between you running your ruby script and the web server running it. Can the web server create a temp file using tempfile?
Just an FYI, I never really uncovered why this was happening. The best I could deduce was that some type of permission issue was preventing Ruby's open-uri commands from working properly.
I opted for queuing these jobs in a db table and running my ruby script via cron periodically. Everything seems to work fine when the ruby script runs with root/sudo perms.
Run on Linux terminal:
sudo -H -u <user> bash -c <your code> where <user> is the Apache's user.
To find Apache's user you can echo("shell_exec(\"whoami\")"); inside your code and run it on browser. whoami works on Linux and Windows, but if you're under Windows, the Apache default user is your user. You can test it anyway in case it's different, but I can't tell how to run the code on Windows like if it's Apache running it.
After that you can have a clue of what's happening. In most cases the problem is the Apache's root folder is different from operating system's folder. So when you run a command with absolute path, the OS consider / and Apache consider /var/www/html on Linux, /opt/lampp/htdocs on Xampp(Linux) and C:/xampp/htdocs on Xampp(Windows). You get the idea i think.