I have a script that calls fswebcam to capture a jpg with my USB camera. I've made it executable with "chmod +x webcam.sh" :
File : /var/www/html/webcam.sh
#!/bin/bash
DATE=$(date + "%Y-%m-%d_%H%M")
fswebcam -r 640x480 /home/pi/webcam/$DATE.jpg
This is working fine in command line without sudo, so I've made a small PHP page :
File : /var/www/html/index.php
<?php
$output = shell_exec('sh /var/www/html/webcam.sh');
echo "<pre>$output</pre>";
?>
When I go to the webpage, I just get a blank page and no jpg is created in my webcam folder.
I got the following error :
Apache2 error log
So I've tried modifying my call in PHP, to :
<?php
$output = shell_exec('/usr/bin/sudo /bin/bash /var/www/html/webcam.sh');
echo "<pre>$output</pre>";
?>
I've also add the following to sudoers file
www-data ALL=NOPASSWD: /path/to/script
But I still get the error : apache2 log error
I've tried everything from this thread : How to run .sh script with php?
Do you have any idea ?
Thanks in advance,
Victor
First off:
Don't use sudo if you don't have a very good reason for it.
sh does not necessarily invoke bash.
sudo expects a password, but you didn't provide any hence the error.
I suggest trying with exec instead of shell_exec (there is a difference between the two):
<?php
exec('/var/www/html/webcam.sh', $output, $exitCode);
echo 'Exit code: '.$exitCode.' <hr />';
echo implode('<br />', $output);
Another source of your problem could be permission related:
The webserver usually runs as a different user.
Make sure the webserver can actually write to the output directory.
Related
I an Ubuntu 16.04 machine running NGINX and PHP. I would like to enable the www-data user (via web browser) to be able to access a PHP page (php-test.php) that will execute either a bash script (script_test.sh) or execute Linux CLI commands using shell_exec or exec.
I have done the following.
Created my bash script file script_test.sh
#!/bin/bash
whoami
echo $USER
echo 'test'
exit
when I run this from CLI, using
./ script_test.sh
It does indeed work and I can see the info echoed out in the CLI.
I then pursued the goal of being able to allow the www-data user run this bash script through a PHP page running on this same machine from NGINX.
I created my php page (php_test.php) and it contains the following
<?php
chdir('/path/to/my/files/');
shell_exec('./script_test.sh'); // ATTEMPT RUN SCRIPT
shell_exec('/path/to/my/files/script_test.sh'); // ATTEMPT RUN SCRIPT
echo 'test 123'; // SIMPLE ECHO IN THE PHP PAGE
?>
I then ran the following to modify the sudoers file, giving www-data access to the bash script
sudo nano /etc/sudoers
to which I added the following line
www-data ALL=NOPASSWD: /path/to/my/files/script_test.sh
I then made sure the script was executable, for the sake of my testing, not worrying about security, I just set it to 777 with the following command
sudo chmod 777 script_test.sh
From there I opened a web browser and browsed to the localhost (NGINX) web server (php_test.php) and the only thing I see on the page is the 'test 123' that I echo from PHP... none of the bash script appears to have run at all. I tailed the NGINX error log and don't see any error at all.
Is there another log that could contain clues on this?
What else should I check here?
The result of shell_exec() is returned as string. To display it in your browser, simply add echo.
<?php
chdir('/path/to/my/files/');
echo shell_exec('./script_test.sh'); // ATTEMPT RUN SCRIPT
echo shell_exec('/path/to/my/files/script_test.sh'); // ATTEMPT RUN SCRIPT
echo 'test 123'; // SIMPLE ECHO IN THE PHP PAGE
?>
See the Return Values in the manual:
The output from the executed command or NULL if an error occurred or
the command produces no output.
Can you try to use passthru instead of shell_exec, and see the output anything?
Also try this, and see if it shows on the log file:
if(file_exists('/path/to/my/files/script_test.sh')) { die('File not found!'); }
shell_exec("nohup /path/to/my/files/script_test.sh > /path/to/my/files/output.log &");
Also, are you running PHP with the www-data user (check your fpm pool)?
Do you have any error on /var/log/syslog or /var/log/auth.log ?
Have you restarted the server after changing the sudo permissions?
What does su - www-data -c "whoami" and su - www-data -s /bin/bash -c "whoami" outputs?
Does su - www-data -s /bin/bash -c "/path/to/my/files/script_test.sh" output something?
I'm in trouble and that much confused about a php shell_exec command.
When the command is execute by PHP I have no error but the execution fails. If I use exactly the same command from a terminal it works.
Here's the command :
/usr/bin/wkhtmltopdf --lowquality --dpi 300 --encoding utf-8 "/tmp/knplabs_snappyxa9otq.html" "/tmp/knplabs_snappyv3pD7h.pdf"
When I lauch this from a terminal :
$ /usr/bin/wkhtmltopdf --lowquality --dpi 300 --encoding utf-8 "/tmp/knplabs_snappyWG9XTd.html" "/tmp/knplabs_snappyv3pD7h.pdf"
Loading page (1/2)
Printing pages (2/2)
Done
But from my php script :
// Construct the previous command
$command = $this->buildCommand($url, $path);
../..
shell_exec($command);
../..
$content = file_get_contents($path);
../..
I've test the output of shell_exec, it's empty.
The log :
Warning: file_get_contents(/tmp/knplabs_snappyv3pD7h.pdf): failed to open stream: No such file or directory in /*****/lib/snappy/SnappyMedia.class.php on line 64
No permission pb in the /tmp directory :
$ ls -la /tmp
total 448
drwxrwxrwt 16 root root 4096 mars 12 21:51 .
../..
I've tried avec the PHP exec() function to get error informations, I just get an "1" error code in return_var and nothing in output.
For information this issue appear on my test server, my desktop computer but not on my notebook. All the 3 are with sames PHP, Apache, Mysql versions.
I don't understand anything ...
Thanks for any help, I'm loosing my mind.
David.
I've found the solution here : Executing wkhtmltopdf from PHP fails
Thanks to Krzychu.
First to get information from the shell_exec command add " 2>&1" at the end of the command. In that way you will get information in return of the command :
$no_output = shell_exec($command);
echo $no_output; // nothing
$output = shell_exec($command . ' 2>&1');
echo $output; // in my case : "cannot connect to X server"
The solution :
Not use the wkhtmltopdf ubuntu package (0.9.9-4)
Use the official package from the Wkhtmltopdf download page
So no need to install xvfb ! (I've seen this advice many times)
Looks like a user's permissions issue.
When you run the command from the terminal, it is the user account, currently used, which does have the right permissions, to run a command in /usr/bin, and execute the specific file.
When you run it from the php script, it is the http server account on your system, which needs the permission to execute the file in /usr/bin. Usually this is the apache user.
How you should setup permissions depends on your system. Just remember that what is allowed for apache, is allowed for anyone accessing your http server.
I have had this problem for ages and adding . ' 2>&1' after the $command has somehow solved the problem.
this:
$output = shell_exec($command . ' 2>&1');
instead of:
$output = shell_exec($command);
No idea why but it works and I'm grateful.
Is it a shared hosting? It seems like shell_exec is a restricted function. Try running error_reporting(E_ALL); ini_set('display_errors', 1); before calling shell_exec.
I stumbled upon the same Problem, in my case an absolut Path in the exec Command like /var/www did not work, I had to use relative Paths from the point where I executed the php File.
I also wanted to notice, that it did not work using shell_exec, however it worked using normal exec command, not sure wheres the difference here.
I want to start program when I enter my webpage, and problem is in permissions(??) because when I try
echo exec('whoami');
I've got valid response (www-data) but when i try code like it:
echo exec('/var/www/./sitesend');
and
echo passthru(/var/www/./sitesend');
I got no response. I tried to
chown www-data /var/www/sitesend
chmod 755 /var/www/sitesend
My C++ app runs correctly, and its sending by NRF infromations to turn lights.
But not work, when enter page app won't run and I don't get any reps in echo.
I don't have a conclusive answer, but you can try a number of things:
Try the follow command to see if www-data may run the command.
sudo -u www-data /var/www/sitesend
Try running a PHP script with the passthru command from the commandline.
See if you're running AppArmor for the Apache process. AppArmor will block execution for files not white listed.
ls /etc/apparmor.d
I'm new in using Linux, I'm trying to write a PHP code which can run .exe linux compatible file, I've made a short shell script
hello bash script:
#!/bin/bash
./program.exe file.mp4 // file.mp4 is an an input for .exe
echo "Hello World!"
shell.php:
<?php
$output = exec ("./hello ");
echo "<pre>$output</pre>";
?>
Now when I run shell.php using web browser it shows Hello World! but the .exe doesn't run, however when I run php using terminal command php shell.php, It works fine.
I think I'm having problems with permissions but I'm new with Linux and I don't know how to solve this.
Update:
I ignored the shell script and I used
<?php
$output = shell_exec ("cd /var/www/ && ./program.exe file.mp4 2>& " );
?>
also I granted access to program.exe
chmod 777 program.exe
the error I receive in the browser :could not open debug.bin!
use the absolute path to hello executable exec("sh path/to/the/file")
I'm using something similar to call an app compiled with mono on a remote ubuntu webserver and return it's output to the calling script.
For any of this to work properly wine needs to be already installed.
On Ubuntu systems try:
sudo apt-get -y install wine
You then need to know the owner of the web server process. If you are running the apache web server try the following:
cat /etc/apache2/envvars | grep "RUN"
The output will look something like this:
export APACHE_RUN_USER=www-data
export APACHE_RUN_GROUP=www-data
export APACHE_RUN_DIR=/var/run/apache2$SUFFIX
Now that you have the name of the process owner, which in this case is www-data you should ensure the file is owned the user and its group:
sudo chown www-data /var/www/program.exe
sudo chgrp www-data /var/www/program.exe
Finally, we can invoke the application from inside our PHP script by passsing it as a parameter to 'wine' and using its full file path.
<?php
$output = shell_exec("wine /var/www/program.exe file.mp4" );
?>
Any output from the above shell command sent to the command line will be saved in the PHP script variable $output.
It looks like you are trying to do some output redirection with your use of program.exe file.mp4 2>& so I've left that off of the example for clairity.
Try using the absolute path, such as exec("sh /path/to/file")
Generally, php is run as www or apache, so make sure that the execute access permission is granted to all user.
I have used php's exec to execute FFmpeg command but its not woking when I open it in browser. But when i run this php file script in terminal it works fine.And my php safe mode is off. please help me to get it solved. my php code is
<?php
$output=exec("ffmpeg -f image2 -i /home/phedra/imgs/image/img%03d.png -r 12 -s 610x489 /home/phedra/imgs/video/out.avi", $out);
echo $out;
echo $output;
?>
try giving full path where the ffmpeg application is located.
e.g.
/usr/bin/ffmpeg
So your function might look like:
$output=exec("/usr/bin/ffmpeg -f image2 -i /home/phedra/imgs/image/img%03d.png -r 12 -s 610x489 /home/phedra/imgs/video/out.avi", $out);
You must check what is the location of "ffmpeg".
I had this problem and it turned out it was Apache's permission on the public directory.
Note: I am running Ubuntu 14 on AWS
After installing FFmpeg I had to change the /var/www/* ownership to www-data.
sudo chown -R www-data:root /var/www
(the www-data is the important part here)
Then I had the following code running, and it works when I access it via URL (Apache)
// test.php
$run = system("/opt/ffmpeg/bin/ffmpeg -i /var/www/html/input.mp4 -vf scale=640:480 /var/www/html/output.mp4 &");
if($run) {
echo "success";
} else {
echo "failed";
}
The /opt/ffmpeg/bin/ffmpeg is where my FFmpeg is running from. Yours might be /usr/bin/ffmpeg or something else. You can locate it by typing locate ffmpeg in the command line and looking through the list it gives you.
The input file was a public .mp4 file and the output.mp4 file was going to the same location.
Run this in your command line: php test.php - works
Run this from your browser: yourwebsite.com/test.php - works
Note that if you are on windows you must use COMMAS. I.E:
$output=exec('"/usr/bin/ffmpeg" -f image2 -i /home/phedra/imgs/image/img%03d.png -r 12 -s 610x489 /home/phedra/imgs/video/out.avi', $out);
Like #Arfeen mentioned in his answer, you should execute the command with the path of ffmpeg, but, the given path in the answer "/usr/bin/ffmpeg" is not always the same.
First locate your ffmpeg by using the command :
which ffmpeg
The result in my case is :
/usr/local/bin/ffmpeg
Then go back to your php code and replace "ffmpeg" in the command by the path of ffmpeg (which is /usr/local/bin/ffmpeg in my case).