PHP exec fails when called from a browser but not from CLI

问题

I have a simple PHP script:

exec('git pull origin master', $shell_output, $output);
print_r($shell_output);
print_r($output)

When I call this via CLI php git.php, it works fine. I get the expected output, and a return value of 0. When I visit the page via a web browser, it fails with a return value of 1.

I've set file permissions to 777, and ensured php.ini doesn't block the exec() function.

回答1:

The CLI runs with the currently logged in user's (you) credentials and it's most probably different from what the web server process uses. Do a exec('whoami') etc. to verify.

回答2:

I was able to fix the issue with some help by Ates Goral.

To debug the issue, I ran:

sudo -u www-data php git.php

to see how the script behaved when run under the www-data user. There were two issues:

www-data did not have its own public key. I created one and added it to the github repo. And the .git folder was not readable by www-data. This was fixed by chowning the directory to give permissions to the group www-data that both I and apache belong to.

来源：https://stackoverflow.com/questions/13097550/php-exec-fails-when-called-from-a-browser-but-not-from-cli