On Your Own Machine

This page will help you get started setting up an environment on your personal computer to let you do most of the labs and MPs without remote connecting to the EWS machines. We highly recommend you attempt programming locally (on your own machine) as the EWS servers have a history of going down, being slow, and/or being overloaded in general. This will also enable you to work on assignments offline.

Please come to office hours or post on Piazza if these instructions do not make sense, or do not work.

Remote Connect

You have two options for remotely working on the EWS Linux cluster:

• Running a full desktop session using FastX: https://it.engineering.illinois.edu/user-guides/remote-access/connecting-ews-linux-fastx
• Connecting to a console session over SSH: https://it.engineering.illinois.edu/user-guides/remote-access/accessing-linux-terminals-remotely-ssh
  • For Mac OS X or any other Unix-like variant, you will need to open a terminal session.
    1. On OS X: Applications->Utilities->Terminal
    2. Then run the command: ssh NETID@linux.ews.illinois.edu (replacing NETID with your NetID)
    3. If this is your first connection, it will then prompt you to accept the public key from the host; type yes at this prompt and hit enter.
    4. At this point you should be prompted for your AD password; note that you will not see any characters displayed as you type.
    5. If your password was successfully accepted you should have a fully functioning EWS shell.
  • For Windows you will need to download http://the.earth.li/~sgtatham/putty/latest/x86/putty.exe.
    1. Once you download PuTTY you will be prompted to enter the address to the server. Use NETID@linux.ews.illinois.edu, substituting in your NetID.
    2. You can save this by clicking the save button to the right of the highlighted default session. Optionally you could name this connection EWS.
    3. Now click connect and click “Yes” if it prompts you to accept the public key of the host machine.
    4. You will be asked to enter your AD password; note you will not see any characters as they are typed.
    5. If your password was successfully accepted you should have a fully functioning EWS shell.

We recommend connecting to a console session since an excessive amount of FastX sessions tends to become unstable on the EWS cluster or ends up refusing connections.

Working Natively

Windows

The Windows Subsystem for Linux (WSL) is an amazing tool allowing Linux to run in Windows natively. To get WSL installed:

1. Follow Microsoft’s instructions for installing WSL, choosing Ubuntu as the distribution: https://docs.microsoft.com/en-us/windows/wsl/install-win10.

2. Continue following Microsoft’s instructions for initializing your Ubuntu distribution: https://docs.microsoft.com/en-us/windows/wsl/initialize-distro

3. Download the packages used for C++ by running the following command to install the packages we will be using:

sudo apt-get update && sudo apt-get install clang-5.0 libc++abi-dev libc++-dev git gdb valgrind graphviz imagemagick gnuplot
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-5.0 100
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-5.0 100
sudo update-alternatives --install /usr/bin/llvm-symbolizer llvm-symbolizer /usr/bin/llvm-symbolizer-5.0 100

Using your Windows Desktop in WSL/Ubuntu

When you start Ubuntu, your shell will begin in the Linux home directory. However, you will likely want to work with files that are somewhere inside of your Windows file system. By default, your C: drive is mounted at /mnt/c.

Some find it useful to create a shortcut to jump directly to your Windows Desktop (or possibly a cs225 folder inside your Windows desktop). To do so:

1. Navigate to your Windows desktop within the Linux shell:

cd /mnt/c/Users/
cd <Your-User-Name-on Windows>  // Use `ls` to find the available users in green
cd Desktop

1. In your Windows Desktop directory you just navigated to, run the following command to create a symbolic link (ex: a shortcut) from your Linux home directory to your Windows desktop to easily navigate there in the future:

ln -s `pwd` ~/desktop

1. In the future when you launch WSL/Ubuntu, you can immediately jump to your Windows desktop by running cd desktop.

Linux

You should make sure you have the following packages installed:

• Clang and libc++ and the libc++abi: The Clang compiler and the libc++ C++ standard library implementation. This provides all of the compiler Utilities. On most distros you will need to make sure you have clang, libc++ and libc++abi (or similar) packages installed.
• Valgrind: A tool for finding memory leaks and general programming errors.
• Graphviz: Graph plotting tools used for assignments which display graphs and trees as images.
• GNUPlot: Plotting tools used for assignments which display graphs and charts as images.
• GDB: The GNU Debugger. We do not officially offer a tutorial for this tool as Valgrind usually suffices, but GDB allows you to step through your code and test specific execution paths.
• Subversion: The revision control system used for turning in assignments. On systems which have a separate package (something like libsvn-dev or subversion-dev) for the header files, you’ll need those too.

After installing the required packages, you should now be able to check out, build, and run assignments as described in their documentation.

Ubuntu >= 14.04

This should get you all of the packages you’ll need:

sudo apt-get update && sudo apt-get install clang-5.0 libc++abi-dev libc++-dev git gdb valgrind graphviz imagemagick gnuplot
sudo update-alternatives --install /usr/bin/clang clang /usr/bin/clang-5.0 100
sudo update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-5.0 100
sudo update-alternatives --install /usr/bin/llvm-symbolizer llvm-symbolizer /usr/bin/llvm-symbolizer-5.0 100

If you have a different version of clang installed, you might need to remove it first. Alternatively, if you don’t mind using a different version of clang, you can use the other version instead—just make sure to test your code on EWS. (You should do that anyway.)

Arch

This should get you all of the packages you’ll need:

sudo pacman -Sy base-devel clang gdb valgrind graphviz imagemagick git gnuplot

You will also need to install libc++ and libc++-abi from the AUR.

The default clang package should work (it’s currently at 6.0), but make sure to test your code on EWS (which will be using clang 5.0). (You should do that anyway.)

macOS

If you experience difficulties installing the software listed below, then please come speak with a TA during office hours, a lab section, or by posting on Piazza.

Compiler, Git

Disclaimer: Especially since the clang versions on EWS and the Mac environment will be different as well as the LLVM environments, please be sure to test your code on EWS as well to make sure it works in our grading environment.

Run

xcode-select --install

to install the Xcode commandline tools. You should run that command even if you already have the commandline tools installed—running it sets up Apple’s version of clang to look for headers in the “regular” *nix places.

Next, we will install the Brew Package Manager for macOS using the following command.

/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

We will now use the brew package manager to install gdb.

brew install gdb

Configure gdb to be a signed application permitted to debug process (gdb will not work without doing this).

1. Open the Keychain Access app (can be found in Applications/Utilities or can be searched for).
2. Click Certificate Assistant > Create a certificate.
3. Set the name of the certificate to gdbcert, Identity Type to Self Signed Root, and Certificate Type to Code Signing.
4. Check Let me override defaults and click Continue.
5. Set Security Number to 1 and Validity Period to 1825 (this means you can use gdb with this certificate for 1825 days. Increase the number for more days. The max is 20 years). Click Continue again.
6. Keep clicking Continue till you see the screen named Key Pair Information. For algorithm, select ECC and for Key Size select 384 bits.
7. Keep clicking Continue till you see the screen named Specify a Location For The Certificate. For Keychain, select System.
8. Finally, you can click the Create button. You may be prompted for you computer password.
9. In the Keychain Access application, choose the System keychain on the left sidebar. Select gdbcert. Right click and open the context menu. Select Get Info. Exapnd the Trust section. Set the Code Signing property to Always Trust.
10. Quit the Keychain Access application.

Now, we will sign gdb. To do so, we must first kill the taskgated process using the following command.

sudo pkill taskgated

We must first wait for the taskgated process to restart. To check whether it has restarted, run the following and see if a /usr/libexec/taskgated entry pops up. (This can take up to one to two minutes).

sudo lsof | grep taskgated

Now, lets sign our gdb application. To do so, run

codesign -s gdbcert /usr/local/bin/gdb

where you may then be prompted for your computer’s username and password. You should now be able to use gdb to debug your code.

Next, we will need to use brew to install valgrind.

To do so, run

brew edit valgrind

and change the URL in the head section from https://sourceware.org/git/valgrind.git to git://sourceware.org/git/valgrind.git then run the following

brew update
brew install --HEAD valgrind

Next, we need to install imagemagick and graphviz with brew. Run

brew install ghostscript imagemagick graphviz