how to use web to invoke php program, and the php program call c program

bellhuang · 01-10-2014, 03:38 AM

with apache as server and safe_mode = off, after the data submitted by form post mode, the php program was invoked, then the php program call c program which located in an other directory by exec command. The problem is that it is seemed that exec command can run, but the c program couldn't be called. How to solve this problem? thanks.

mpapet · 01-10-2014, 01:55 PM

Does the apache user have permission to execute your program??

Does the apache server have access to the executable's path??

Smokey_justme · 01-10-2014, 02:02 PM

Could you at least provide some sort of error message or more details about "exec command can run, but the c program couldn't be called"?

Also, a copy/paste of your relevant php lines would be great... Maybe there lies the problem..

bellhuang · 01-10-2014, 07:23 PM

1. In the log/messages exists:
Executable '/usr/local/bin/excutableCprogram' doesn't belong to any package

2.
a. test1.php
<?php exec("/usr/local/bin/excutableCprogram $a",$output); ?>
It can run with php test1.php

b. test2.php
<?php
$a=$_POST['data'];
$output=NULL;
exec("ls /usr/local/bin/",$output);
?>
It can run after form submitted.

c. test3.php
<?php
$a=$_POST['data'];
$output=NULL;
exec("/usr/local/bin/excutableCprogram $a",$output);
?>
It can't output anything.

thanks.

bellhuang · 01-10-2014, 08:23 PM

Maybe it give some hints: example in a can only run with root, general user can't output anything. Is it helpful set env to locate executable program as ls command?

Smokey_justme · 01-11-2014, 12:59 PM

Please run the following php script and see the output:

PHP Code:


			
<?php



echo "<pre>"; //Just in case you run it from a browser

echo "Exec returned: " . exec('echo "All Ok!"',$output) . "\n";

echo $output;

echo "</pre>";

If you'll see All Ok!.. Then it all works as expected...

If it does, can you run the executableCprogram as a normal user and see if it works..
Also try (while being root, since it won't work otherwise):

Code:

su -c /usr/local/bin/executableCprogram apache

Please replace 'apache' in the last command with the user in which your apache server works (usually 'apache' or 'httpd')

bellhuang · 01-12-2014, 02:55 AM

hi Smokey_justme, it can output "ALL OK", I'll try your other suggestion. Thanks.

bellhuang · 01-12-2014, 04:17 AM

I guess it's a privilege problem, can change to other user in exec function from php scrip?

Smokey_justme · 01-12-2014, 04:34 AM

Not really.. But can't you simply

Code:

chmod a+x /usr/local/bin/executableCprogram

?

bellhuang · 01-12-2014, 07:39 AM

in command line, with root privilege, the program can run in its directory, while using an other user e.g. user1, it can't work;
so I change the path to 777, user1 can work; but the browser still can't invoke the program.
What about to run it with cgi?

bellhuang · 01-13-2014, 06:09 AM

I have tried an other c program, it is no problem. So, maybe the previous program use unsuitable functions cause to its failure. Thanks.