Trying to execute python command through php but permission errors

Question

I uploaded an image file and copied it from temporary folder to a folder inside /var/www/. Then, tried to execute a python command via php where the exec() command is in the following format.

exec('python file.py $_FILES["file"]["name"]');

and even doing the following does not work,

exec('python file.py' + $_FILES["file"]["name"]);

In the python side, I am trying to read the filename and do some processing on it and save the image.

source = cv2.imread(sys.argv[1])
#some processing 
cv2.imwrite("upload/result.png", resultimage)

Note: The uploaded images are being shown as owned by www-data group after upload. I have added my user to the www-data group and have done the following as well.

sudo chown -R tilaprimera:www-data upload
sudo chmod -R g+s upload

where here upload is my folder storing the uploaded images. I have made the python script executable too,

sudo chmod +x script.py 

and also the script.py is perfectly running okay as

./script.py 

Why is the python script not executing via the php?

Answer 1

In the python script file, the directory change was done as

os.chdir('/var/www/upload')

and in the php side, I gave the full path for the python script to run

exec('python /var/www/upload/script.py ' . $_FILES["file"]["name"]);

This way, the problem got solved.