How i can run function exec in PHP - php

I can't add * to my code to find file
this code work
exec("mediaconvert -t wav -i /home/20220228/11/23401.rec -o /var/www/html/test.mp3");
if i add a the *, it don't work
exec("mediaconvert -t wav -i /home/20220228/11/*01.rec -o /var/www/html/test.mp3");
p.s. in path is only one file, when i try execute this code from shell it work. Pls help me)

Filename expansion and other bash-specific features may/will not work in other shells (e.g. standard POSIX). If your command with * is not executed in bash/compatible, it won't work as expected. You need to verify the environment/shell that your PHP installation executes commands in.
Run the following test script:
<?php
exec('echo "$SHELL"', $out);
var_dump($out);
When I run the PHP script directly on CLI, I get "/bin/bash" for the shell that's called. When I run it via browser, curiously I get "/sbin/nologin" instead. There are different environments for user apache that executes PHP via browser calls, and the "actual" user logging in via SSH. Bash shell is not available for the Apache user by default.
These results are from a Centos7 server with Apache 2.4/PHP 8.1.4 running. Your mileage may vary. Bottom line: if the command you are executing depends on bash-specific features, it must execute in a bash environment, or another shell that supports the required features.
If bash is not available, your other option is using e.g. glob to get files matching the pattern in your directory, and then loop over them while executing the command for each specific file.
Edit: As pointed out by #Sammitch (see comments), /sbin/nologin is a common "shell name" choice for non-login users, and most likely uses /bin/sh. This should still allow for filename expansion/globbing. Testing browser script call with exec('ls *.php', $out); the wildcard functions as expected.
You may find this question/answer relevant: Use php exec to launch a linux command with brace expansion.

I recommend you do the opposite. First, get the files you want to input then you exec. For instance:
$input_files = ...
exec("mediaconvert -t wav -i " . $input_files . " -o /var/www/html/test.mp3");

You can try to find files with glob() function and after that you can use exec(). You can try a similiar solution with the following code:
$input_files = '/home/20220228/11/*01.rec';
foreach (glob($input_files) as $filename) {
exec("mediaconvert -t wav -i " . $filename . " -o /var/www/html/test.mp3");
}

Related

Allow PHP/Apache to shell_execute commands on Ubuntu

I'm trying to execute a command through PHP with shell_exec. The PHP file is hosted by Apache on my Ubuntu server.
When I run this:
echo shell_exec("ps ax | grep nginx");
Then I get to see data. But when I run another command, for example:
echo shell_exec("cat /usr/local/nginx/config/nginx.config");
Then it's not showing anything at all. But when I copy that command and paste it in my terminal, then it executes fine.
My Apache server is running as user www-data. So I edited sudoers and added this line:
www-data ALL=(ALL:ALL) ALL
I know this is a security risk, but I wanted to make sure (for now) that www-data is able to execute all commands. But, for some reason I'm still not able to execute all commands with my PHP script.
Anyone any idea what to do?
have you read http://php.net/manual/en/function.shell-exec.php
There is quite a discussion in comments section. Top comment is:
If you're trying to run a command such as "gunzip -t" in shell_exec and getting an empty result, you might need to add 2>&1 to the end of the command, eg:
Won't always work:
echo shell_exec("gunzip -c -t $path_to_backup_file");
Should work:
echo shell_exec("gunzip -c -t $path_to_backup_file 2>&1");
In the above example, a line break at the beginning of the gunzip output seemed to prevent shell_exec printing anything else. Hope this saves someone else an hour or two.
echo shell_exec("sudo cat /usr/local/nginx/config/nginx.config");
Try that.

PHP exec in background using & is not working

I am using this code on Ubuntu 13.04,
$cmd = "sleep 20 &> /dev/null &";
exec($cmd, $output);
Although it actually sits there for 20 seconds and waits :/ usually it works fine when using & to send a process to the background, but on this machine php just won't do it :/
What could be causing this??
Try
<?PHP
$cmd = '/bin/sleep';
$args = array('20');
$pid=pcntl_fork();
if($pid==0)
{
posix_setsid();
pcntl_exec($cmd,$args,$_ENV);
// child becomes the standalone detached process
}
echo "DONE\n";
I tested it for it works.
Here you first fork the php process and then exceute your task.
Or if the pcntl module is not availabil use:
<?PHP
$cmd = "sleep 20 &> /dev/null &";
exec('/bin/bash -c "' . addslashes($cmd) . '"');
The REASON this doesn't work is that exec() executes the string you're passing into it. Since & is interpreted by the shell as "execute in the background", but you don't execute a shell in your exec call, the & is just passed along with 20 to the /bin/sleep executable - which probably just ignores that.
The same applies to the redirection of output, since that is also parsed by the shell, not in exec.
So, you either need to find a way to fork your process (as described above), or a way to run the subprocess as a shell.
My workaround to do this on ubuntu 13.04 with Apache2 and any version of PHP:
libssh2-php, I just used nohup $cmd & inside a local SSH session using PHP and it ran it just fine the background, of course this requires putting certain security protocols in place, such as enabling SSH access for the webserver user, so it would have exec-like permissions then only allowing localhost to login to the webserver ssh account.

Using PHP and Bash to log into an external server via SSH

I'm trying to set up a centralized server which is in charge of monitoring my other servers. This centralized server needs to be able to collect particular information/metrics about a specific server (such as df -h and service httpd status); but it also needs to be able to restart Apache if needed.
If it wasn't for the Apache restart, I could write a listening script to provide a means of giving the centralized server the data it needs without having to SSH in. But because I also want it to be able to restart Apache, it needs to be able to log in and initiate scripts through a combination of PHP and Bash.
At the moment, I'm using PHP's shell_exec to execute this (very simple) Bash script:
#!/bin/sh
ssh -i /path/to/keyFile.pem ec2-user#x.x.x.x;
I'm accessing the external server (which is an EC2 instance) through a private IP. If I launch this script, I can log in without any problem - the problem comes, however, when I then want to send back the output for commands like the ones I've listed above.
In a Bash script, how would I output a command like df -h after SSHing into another server? Is this possible?
There is a PECL extension for SSH.
Other than that you'll probably want to either use the &$output parameter of exec() to grab the output:
$output = array();
exec('bash myscript.sh', $output);
print_r($output);
Or use output redirection
$output = '/path/to/output.txt';
exec("bash myscript.sh > $output");
if( file_exists($output) && is_readable($output) ) {
$mydata = file_get_contents($output);
}
and, of coure, this all assumes your script looks like what jeroen has in his answer.
You could use:
ssh -i /path/to/keyFile.pem ec2-user#x.x.x.x 'df -h'
or for multiple commands:
ssh -i /path/to/keyFile.pem ec2-user#x.x.x.x 'ls -al ; df -h'
That works from the command line but I have not tried it via php's exec (nor on Amazon to be honest...).
If you're doing ssh I'd suggest phpseclib, a pure PHP SSH implementation. It's a ton more portable than the PECL SSH extension and more reliable too.

php command line exec() multiple execution and directories?

I am trying to Execute a multiple commands in php using exec() and shell_exec but i am getting a null value back which i shouldn't and nothing is happening (if i copy and paste the strings below in the command line it will work fine and accomplish the job needed) this is the commands i am using:
$command = "cd /../Desktop/FolderName;";
$command .= 'export PATH=$PATH:`pwd`;';
$command .= 'Here i execute a compiler;';
and then i use the escapeshellcmd()
$escaped_command = escapeshellcmd($command);
then
shell_exec($escaped_command);
any ideas what i am doing wrong and i also tried escapeshellarg() instead of escapeshellcmd()?
Solution: the Problem was the permission of the execution compiler for other owners is non and this was the problem.
because when you are using exec() function in php the owner of the file will be www-data so you need to give permission for the www-data either from the ACL of ubuntu or whatever linux based operating system(you can know the owner by doing this exec('whoami')), or by the files you need to execute.
(Sorry my bad English)
On Linux you can add your Commands in a Shell Script.
You can put this in any file:
#!/bin/bash
cd /../Desktop/FolderName
export PATH=$PATH:`pwd`
EXECUTE COMPILER
And save this as fille.sh
Then, add execution permissions:
chmod +x path/to/file.sh
From PHP, you can call this Script executing:
shell_exec('sh path/to/file.sh');
Hope this helps!

PHP exec() Not Working With ffmpeg

I'm attempting to run the following command in PHP (on Ubuntu):
<?php
if (exec("/home/johnboy/ffmpeg/ffmpeg -i test1.mp4 -acodec aac -ab 128kb -vcodec mpeg4 -b 1220kb -mbd 1 -s 320x180 final_video.mov"))
{ echo "Success"; }
else { echo "No good"; }
And I always get "No good" echoed back, and no file created.
Interestingly, if I run the same exact command in Shell, it works, no problems.
Also, when I run the same code above, but subsitute "whoami" instead of the ffmpeg stuff, it works. (It echoes back "Success")
Any ideas on why this wouldn't be working? Thanks.
get the stderr will give the result
try
ffmpeg -i inputfile [more_params] 2>&1
Can the apache/web user reach /home/johnboy/ffmpeg/ffmpeg? That is, perhaps /home/johnboy is 0700 instead of 0755?
Perhaps there are resource limits affecting loading of such a large program and all its libraries?
If you run the script to the php cli sapi, does it behave correctly? Even when running as the apache user?
What does strace -ff show when the apache web user runs the php script through the php cli?
Use this
$ffmpeg = "ffmpeg Installed path";
$flvfile = "source video file with root path";
$png_path " "Destination video file with root path and file type";
exec("$ffmpeg -y -i $flvfile -vframes 1 -ss 00:01:60
-an -vcodec png -f rawvideo -s 110x90 $png_path");
You are using relative paths to the file names. Are you sure you are executing the command in the right directory?
There would be some issues if you want to execute something that way.
1. Maybe you have some permission issue, the webserver have limitation to handle some execution to the system.
2. Maybe your path file is incorrect.
3. you can try to use shell_exec to perform the execution to the system.
Anyway, what I would do to make my execution would go smoothly are,
I will write 2 programs with message passing included between them, for example client server program.
The server would wait some messages from the client to execute some command (all of the command, it would be no permission issues). All you have to do in you web is to call your client application.
What I emphasize is to build some interface from web and the system. It would solve a lot of problem with permission issues.
hope this help.
The function exec() only returns the last line of output, I suspect that the last line of that command is blank. if you want the entire contents of the command you should use shell_exec().
Also keep track of where the command is executing, try: print(shell_exec("pwd"));
Enable safemode and it will work
$output = shell_exec('/home/person/www/ffmpeg 2>&1');
echo "<pre>$output</pre>";
Notice the 2>&1 part ...

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