A couple of months ago, I built a serial connection library in C for the Arduino Micro-controller. I was thinking about how awesome it would be if I could write a PHP wrapper for the library.
I wrote a PHP extension with just one function called "acm_get_door()," which should either return a -1, 0, or 1, depending upon the status of a certain pin on my Arduino. If it returns -1, then that means that the connection wasn't set.
So after loading up the custom extension and changing both of my php.ini files, and restarting everything else, I ran this test via the CLI:
$ php -r 'echo acm_get_door();'
It returned a '1'. I was excited, so I played with the circuitry to see if I could get a '0'. Well I did and I thought my extension was working perfectly.
I then went to a .php file in my test webserver (same computer) and tried to run the function. I got a '-1' result from it. The extension does load, but I can't seem to initiate a connection to the Arduino.
I am wondering if it might be a permissions thing regarding access to certain files. The function needs to get access to a file called "/dev/ttyACM0" which it is able to in the CLI version. It is possible that my Apache web server doesn't have the permissions to access that file, and if so, how would I be able to adjust stuff so that it does?
Thank you for your time.
Probably the group has permissions to read/write the device.
Therefore, find out the group owner of the device using ls -l /dev/tty/ACM0. Then, add yourself to the group using:
sudo adduser <me> <the_group>
(where me is your username and the_group is the group of the device)
You might need to log out/in to gain the effect of the changed group permissions.
Okay, thanks to John Jesus, I just had to change the permissions of the file /dev/ttyACM0.
It was set to 660, 666 seems to work (though it it probably a bad idea).
Related
$output = shell_exec('echo "php '.$realFile.'" | at '.$targTime.' '.$targDate.' 2>&1');
print $output;
Can someone please help me figure out why the above line isn't doing what it's supposed to be doing? The idea is for it to create an 'at' job that will execute a php script. If I switch to the user apache(which will ideally control the at function when the php file is complete) I can run
echo "php $realFile.php" | at 00:00 05/30/17
and it'll do EXACTLY what I want. The problem is in the above snippet from my php file it will not create the at job correctly. when I do a at -c job# on both of them the job made from my file is about a 3rd the length missing the User info and everything. It basically starts at PATH= and goes down. Doesn't include HOSTNAME=, SHELL=, SSH_CLIENT=, SSH_TTY=, USER=. I assume it needs most of this info to run correctly. The end output (below)is always the same though it just doesn't have any of the top part for some reason. Let me know if you need more info. I didn't want to paste all of my code here as it contains job specific information.
${SHELL:-/bin/sh} << 'marcinDELIMITER0e4bb3e8'
php "$realFile".php
marcinDELIMITER0e4bb3e8
It doesn't seem to be a permission issue because I can su to apache and run the exact command needed. The folder the files are located in are also owned by apache. I've also resulted to giving each file I try to run 777 or 755 permissions through chmod so I don't think that's the issue.
I figured out a coupe ways around it a while back. The way I'm using right now is an ssh2 connect to my own server as root and creating it that way. No compromise as you have to enter the password manually each time. Really bad work around. The main issue is that apache doesn't have the correct permissions to do everything needed for the AT job so someone figuring that out would be awesome. Another option I found on a random webpage would be to use sudo through the php script, but basically the same minus having to reconnect to your own server. Any other options would be appreciated.
Reading the manual and logs would be a good place to start. In particular:
The value of the SHELL environment variable at the time of at invocation will determine which shell is used to execute the at job commands. If SHELL is unset when at is invoked, the user’s login shell will be used; otherwise, if SHELL is set when at is invoked, it must contain the path of a shell interpreter executable that will be used to run the commands at the specified time.
Other things to check are that the user is included in at.allow, SELinux is disabled and the webserver is not running chrrot.
I'm trying to execute a command through shell_exec in php. But I'm getting an error.
My code :
shell_exec('groovy log_analyser1.groovy').
But I'm getting this error :
sh: groovy: command not found
Put groovy installation somewhere sane (/usr/local or /opt or whatever your ops team allows you) and then call groovy with the absolute path.
Since you have currently installed in in your root users ~, other users (like the user your php/httpd runs as) don't have access to it (for good reasons).
Even if you would use the same user as your php/httpd and use GVM there you will have a hard time to make this work properly, since GVM relies on some scripts to run. So just copy from your GVM files (~/.gvm/groovy/<version>) where it's easy for all users to access it.
Finally got the output. I have moved the groovy directory from /root to /usr/share/. Then gave the groovy path in my php file. Now its working fine. To set java environmental variable.
I have set this putenv("JAVA_HOME=/usr/share/java/jdk1.7.0_03/");
$result = shell_exec('/usr/share/groovy/2.4.3/bin/groovy log_analyser1.groovy');
Thanks Cfrick for the help.
echo $result;
I have two users on Ubuntu, www-data and labor, both are in the group chiara.
Both users can do
>chown :chiara some_file
>chgrp chiara some_file
I have a python test.py script that uses
import os
os.system('whoami') # displays 'www-data' in both cases
res = os.system('chown :chiara some_file')
print res # 0 when called from shell, 256 when called from php script
When I call this script as either user, it works properly.
However, when I call this script from a php script in apache
shell_exec('test.py')
it does not work - despite the displayed user is 'www-data'.
This problem persists if I change 'chmod' this into 'chgrp'.
Also, using os.chown does not work. Seems like a general permission problem to me...
EDIT: using subprocess.Popen in python, I could retrieve the error message
changing group of '/absolute/path/to/some_file': Operation not permitted
EDIT 2: I think of surrender on this question... in my specific application, "chmod 777" on the directories is sufficient (that works!). However, I'd just like to understand what went wrong.
I'm brand new to ruby and Watir, here's my issue...
I have a MySQL DB with test data that I need. I've done a lot in the past with this data and so I have a whole library of PHP tools for accessing this data, marking data as in use/used/bad/etc, and in general I have a lot of time invested in the PHP framework. So I'd really like to use the PHP framework as a wrapper around the Watir script - for example, use PHP to grab test user login data from the DB and pass it to the ruby script for processing.
I now have sites with javascript that need work/testing and PHP & cURL can't deal with this. So I'm working with Watir-WebDriver on Ubuntu 10.10 (Maverick, Desktop not Server) for these sites. The problem I'm having is with the use of PHP's shell_exec of the ruby script with all the Watir code.
The PHP shell_exec is executing the file - I can see it because I have some puts lines in the file which are being displayed. However, the code appears to be failing on the line
ff = Watir::Browser.new :firefox
I'm not getting an error from PHP.
The PHP line is:
echo shell_exec('ruby /var/www/watir_test.rb');
The ruby script works fine when I call it from a terminal window with the line:
ruby /var/www/watir_test.rb
I originally expected this was a permissions issue since it worked from the command line but not from a browser. However, since it can call the file well enough to return the hardcoded data I've provided for the test then ruby file permissions don't seem to be the issue. Could there be a permissions issue with opening a Firefox window from the www-data user?
When I run
ruby -d -v /var/www/watir_test.rb
I get:
{:extension=>:webdriver} {"app.update.enabled"=>"false"} {"browser.link.open_newwindow"=>"2"} {"browser.shell.checkDefaultBrowser"=>"false"} {"extensions.update.enabled"=>"false"} {"security.warn_entering_secure.show_once"=>"false"} {"webdriver_assume_untrusted_issuer"=>true} {"startup.homepage_welcome_url"=>"\"about:blank\""} {"browser.tabs.warnOnClose"=>"false"} {"extensions.update.notifyUser"=>"false"} {"toolkit.networkmanager.disable"=>"true"} {"security.warn_entering_weak.show_once"=>"false"} {"webdriver_firefox_port"=>"7055"} {"browser.download.manager.showWhenStarting"=>"false"} {"extensions.logging.enabled"=>"true"} {"network.manage-offline-status"=>"false"} {"network.http.max-connections-per-server"=>"10"} {"security.warn_submit_insecure"=>"false"} {"security.warn_entering_weak"=>"false"} {"security.warn_leaving_secure"=>"false"} {"prompts.tab_modal.enabled"=>"false"} {"security.warn_viewing_mixed.show_once"=>"false"} {"dom.max_script_run_time"=>"30"} {"webdriver_accept_untrusted_certs"=>true} {"browser.safebrowsing.enabled"=>"false"} {"security.warn_leaving_secure.show_once"=>"false"} {"signon.rememberSignons"=>"false"} {"javascript.options.showInConsole"=>"true"} {"app.update.auto"=>"false"} {"browser.EULA.3.accepted"=>"true"} {"browser.tabs.warnOnOpen"=>"false"} {"dom.disable_open_during_load"=>"false"} {"network.http.phishy-userpass-length"=>"255"} {"security.warn_entering_secure"=>"false"} {"browser.startup.homepage"=>"\"about:blank\""} {"browser.EULA.override"=>"true"} {"browser.dom.window.dump.enabled"=>"true"} {"browser.startup.page"=>"0"} {"browser.link.open_external"=>"2"} {"browser.search.update"=>"false"} {"browser.sessionstore.resume_from_crash"=>"false"} {"security.warn_viewing_mixed"=>"false"} {"dom.report_all_js_exceptions"=>"true"} {"webdriver_enable_native_events"=>false} {"devtools.errorconsole.enabled"=>"true"}
How do I get PHP to execute the shell_exec properly? The script works and my initial tests were run using firewatir (which shell_exec ran fine) but I am really wanting to use Watir-WebDriver instead of FireWatir - WatirWebDriver should be capable of running a Chrome browser (and IE on a Windows machine) while FireWatir can only run Firefox.
Thanks
Gabe
Here's my "Create Browser" code:
# Include the RubyGems file
require 'rubygems'
# Include the Watir-WebDriver file.
require 'watir-webdriver'
# Create the necessary objects
def create_browser(proxy)
# Setup the proper Firefox Profile
profile = Selenium::WebDriver::Firefox::Profile.new
profile.proxy = Selenium::WebDriver::Proxy.new :http => proxy
puts "<br>Using proxy " + proxy + "..."
#ff=FireWatir::Firefox.new :profile => profile
ff = Watir::Browser.new :firefox #, :profile => profile
puts "<br>Firefox ready..."
return ff
end
If the server is headless, you should install the headless gem so that Firefox can work.
require 'watir-webdriver'
require 'headless'
headless = Headless.new
headless.start
b = Watir::Browser.start 'www.google.com'
puts b.title
b.close
headless.destroy
See: http://watirwebdriver.com/headless/
It't a permission problem, the PHP script runs with the permissions of the server, normally apache.
You can do a sudo www and try to run the script then with rb to see if there is a problem when running ruby with the server user.
Put the two lines of code that is below at the very top of your PHP script. The result of this is that when you browse to your PHP page with your browser it will display exactly what the errors are, including any permission errors.
ini_set("display_errors",1);
error_reporting(E_ALL);
So a recent update to Firefox killed it's support for Watir (no JSSH update if I remember). As a result I rewrote what little code I had for Selenium::WebDriver. But I'm thinking that isn't particularly relevant (its included in case it is relevant I don't know it).
My ultimate solution was to use phpseclib. This allows me to SSH into the machine via their SSH2 PHP class. Once logged in as my typical username (with typical password) I was able to fire off a headless version of my script no problem. The only real issues this creates is that I now have to view everything that's going on through log files and screenshots but that was likely to be true no matter what solution I came up with.
phpseclib needs your username and password for the server (at least until you set some form of public private key pair). So I wouldn't want to do this on a publicly available machine without a couple of layers of security - like setting .htaccess to deny read access to the file with the login data, encrypting the password stored in the file, etc. However, for my purposes I'm logging into one machine on my LAN from another machine on my LAN. The password is only good on my LAN (not my web servers) and while my LAN can see out it should not be (easily) available to the rest of the world (to the best of my knowledge). So the security concerns are minimal.
I never did figure this out. Headless isn't the answer to getting PHP to exec the script. I'm pretty sure it is a permissions issue with Firefox's executable but I can't be positive until I find an actual fix.
Ultimately I've had to break up the tool where PHP manages the DB and task scheduling. Then PHP creates text files with all the data necessary for ruby to run the browser to right site, login, etc, etc... Then ruby moves the data file to one of a few different folders (success, failure, bad login, etc) and adds some text to the data file. Finally PHP parses all this info in the moved text files and updates the DB with that info.
It's less than ideal but it is getting the job done. Now I just need to figure out how to run all of this with mutliple threads...
Thanks for the help
I'm on a foreign linux system and need to determine the user that apache runs on (and so does php).
The aim:
I need to get the owner of the script (this is no problem as I can use SplFileInfo) and compare it to the owner of the apache process.
I'm open to any alternative proposals.
Regards,
Mario
Edit:
Additional info:
The script is a thumbnail generator, that uses an XML file to generate thumbs from larger images. The script needs to create folders and write files. As I cannot influence the php configuration and I do not have any shell access, this has to be done very silently.
The creation process stopps via exception and sends a mail on failue. As most of php's function cannot throw exceptions on failue, I need some manual checks to determine the environment I'm in. Therefore I need the apache user to compare it to some directory or fileowner.
You can call the php exec function to execute whoami:
<?php echo exec('whoami'); ?>
see posix_getuid() and posix_getpwuid()
Some complicated answers here.
This works for me:
$user = getenv('APACHE_RUN_USER');
Not sure if this is just a new thing that been added to apache since this question was asked but it's definitely there now.
phpinfo will dump a lot of system information. For apache2 installs, there is a section that displays the apache user and group ids. Try creating a php script that just has one line, a call to phpinfo(), and open it in your web browser.
Some php script must be run on apache user (cli), whoami is not appropriate in that case.
Here is my solution :
$output = exec('apachectl -S 2>/dev/null | grep User');
$apacheUser = preg_match('/name="([^"]+)"/', $output, $match) ? $match[1] : 'www-data';