I have a very simple PHP script to try to use the exec command. The code is
<?php
// outputs the username that owns the running php/httpd process
// (on a system with the "whoami" executable in the path)
echo("test<br>");
echo exec('whoami');
echo("test");
?>
However when I access the page, it just prints out:
test
test
It does not print the output from "whoami" command, which when run from command line displays
me
What is the problem here? I cannot work it out.
Thanks a lot!
(on a system with the "whoami" executable in the path)
PATH, like all environment variables, is not system-wide but ultimately per-process.
That is, though your typical bash session may well include the path to this executable in PATH, the environment in which your PHP script is running (say, an Apache CGI context) does not. This may be for any reason.
Provide an absolute path to whoami, instead.
Related
In my php code:
exec(test.sh);
and test.sh has code:
echo "Hi this is test?" | espeak --stdout > demo.wav
But nothing happen. No error, No output.
If i try to execute test.sh from terminal that it will work perfectly. So why it not run on my php.
Can someone help me?
How do you run your PHP script? With php-cli (in shell mode)? HTTP (Apache, ...)?
It could be a path problem. Could you give us the path of your test.sh, the path of your php script or the URI which is called to run the PHP if you use apache or other HTTP server?
the apache user will need write access to the current working directory (presumably the same directory that contains your php script and test.sh).
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
I am having difficulty with the PHP exec() function. It seems to not be calling certain functions. For instance, the code echo exec('ls'); produces no output whatsoever (it should, there are files in the directory). That main reason this is a problem for me is that I'm trying execute a .jar from a PHP exec() call.
As far as I know I'm calling the java program properly, but I'm not getting any of the output. The .jar can be executed from the command line on the server. (For the record, it's an apache server).
My php for the .jar execute looks like this:
$output = array();
exec('java -jar testJava.jar', $output);
print_r($output);
All I get for output from this exec() call is Array().
I have had success with exec() executing 'whoami' and 'pwd'. I can't figure out why some functions are working and some aren't. I'm not the most experienced person with PHP either, so I'm not too sure how to diagnose the issue. Any and all help would be appreciated.
The reason why you are not able to execute ls is because of permissions.
If you are running the web server as user A , then you can only ls only those directories which have permissions for user A.
You can either change the permission of the directory or you can change the user under which the server is running by changing the httpd.conf file(i am assuming that you are using apache).
If you are changing the permissions of the directory, then make sure that you change permissions of parent directories also.
To change the web server user, follow following steps:
Open the following file:
vi /etc/httpd/conf/httpd.conf
Search for
User apache
Group apache
Change the user and group name. After changing the user and group, restart the server using following command.
/sbin/service httpd restart
Then you will be able to execute all commands which can be run by that user.
EDIT:
The 'User' should be a non-root user in httpd.conf. Apache by default doesnot serve pages when run as root. You have to set user as a non-root user or else you will get error.
If you want to force apache to run as root, then you have to set a environment variable as below:
env CFLAGS=-DBIG_SECURITY_HOLE
Then you have to rebuild apache before you can run it as root.
I have found the issue - SELinux was blocking PHP from accessing certain functions. Putting SELinux into permissive mode has fixed the issues (although, I'd rather not have to leave SELinux in permissive mode; I'd rather find a way of allowing certain functions if I can).
I have a solution:
command runs from console, but not from php via exec/system/passthru.
The issue is the path to command. It works with the absolute path to command
So that:
wkhtmltopdf "htm1Eufn7.htm" "pdfIZrNcb.pdf"
becomes:
/usr/local/bin/wkhtmltopdf "htm1Eufn7.htm" "pdfIZrNcb.pdf"
And now, it's works from php via exec
Where command binary you can see via whereis wkhtmltopdf
Tore my hair out trying to work out why PHP exec works from command line but not from Apache. At the end, I found the following permissions:
***getsebool -a | grep httpd*** ---->
**httpd_setrlimit --> off
httpd_ssi_exec --> off
httpd_sys_script_anon_write --> off**
USE: setsebool -P httpd_ssi_exec 1
SEE: https://linux.die.net/man/8/httpd_selinux
Your problem is not an execution issue but the syntax of the exec command. The second argument is always returned as an array and contains a single line of the output in each index. The return value of the exec function will contain the final line of the commands output. To show the output you can use:
foreach($output as $line) echo "$line\n";
See http://php.net/manual/en/function.exec.php for details. You can also get the command's exit value with a third argument.
I am trying to run a shell script from a php script.
I have complete control of the environment (unix on mac), I should have all the permissions, etc. set correctly.
The web script is in /htdocs/
The shell script can be executed from anywhere so when I go to /htdocs/ in the shell, I can easily run it like this:
$ my_shellscript
.. but when my php script (which is located in htdocs) tries to call it:
shell_exec('my_shellscript');
I get nothing.
I have proven the script can be called from that location and I have temporarily granted full access to try to get it working somehow. I am going crazy, please help.
If you know of some other way of triggering a shell script via the web that would be fine.
Thanks in advance.
well i got few weeks same problem, the solution is to check if the apace has the permission to execute your script. You could also try to run the script in php cli.
Since it is a shellscript, it needs to be invoked with the path prefix. My guess is you need to do this:
shell_exec('./my_shellscript');
First thing: make sure php isn't running in Safe Mode
Next thing: Try running it with the exec() function and using the full path (e.g. /var/www/htdocs/my_shellscript)
Try doing
echo shell_exec('my_shellscript 2>&1');
which will capture the script's stderr output and print it out. If something inside the script is failing, this output would otherwise be lost when not being run interactively.
I have a multithreaded cli downloader for ubuntu called Aria2c.
I've been trying to get a php script to run aria2c and download a file using shell_exec, but i can't seem to get it to work. Ultimately I plan to have an input box on a page where I can enter a link and aria would download it.
Here's the code I've come up with (for now im inputting the link manually):
<?php $dl = shell_exec('aria2c -d /home/user/ www.downloadlink.com'); ?>
Note that the aria2c command I specified works well in the shell; and the directory I'm attempting to download to is set to '777'.
I'm baffled as to why it's not working, any ideas?
PS: I prefer to use aria rather than the alternatives because it is multithreaded and it supports cookies.
Check if PHP is running in safe_mode. shell_exec won't work if safe_mode is on.
EDIT: aria2c was not referenced with a full path. Referencing it like this: shell_exec('/path/to/aria2c -d /home/user/ www.downloadlink.com') works.
I'll make the assumption that you are running PHP through a web server. In such case, it's very unlikely that the web server has permission to write into your user's home directory: Apache runs as daemon with the credentials of a limited user. Also, the PATH env variable in Apache is not necessarily the same as your user's PATH. Last but not least, you don't check the return value or the script output.
Try something like this:
<?php
exec('/path/to/aria2c -d /tmp www.downloadlink.com', $output, $return_var);
var_dump($output, $return_var);
?>
You can get the full path for aria2c with:
which aria2c