Add gitian build guide

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doc/gitian-building.md

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+Gitian building
+================
+
+*Setup instructions for a gitian build of Bitcoin using a Debian VM or physical system.*
+
+Gitian is the deterministic build process that is used to build the Bitcoin
+Core executables [1]. It provides a way to be reasonably sure that the
+executables are really built from source on github. It also makes sure that
+the same, tested dependencies are used and statically built into the executable.
+
+Multiple developers build the source code by following a specific descriptor
+("recipe"), cryptographically sign the result, and upload the resulting signature.
+These results are compared and only if they match, the build is accepted and uploaded
+to bitcoin.org.
+
+More independent gitian builders are needed, which is why I wrote this
+guide. It is preferred to follow these steps yourself instead of using someone else's
+VM image to avoid 'contaminating' the build.
+
+[1] For all platforms except for MacOSX, at this point. Work for deterministic
+builds for Mac is under way here: https://github.com/theuni/osx-cross-depends .
+
+Table of Contents
+------------------
+
+- [Create a new VirtualBox VM](#create-a-new-virtualbox-vm)
+- [Connecting to the VM](#connecting-to-the-vm)
+- [Setting up Debian for gitian building](#setting-up-debian-for-gitian-building)
+- [Installing gitian](#installing-gitian)
+- [Setting up gitian images](#setting-up-gitian-images)
+- [Getting and building the inputs](#getting-and-building-the-inputs)
+- [Building Bitcoin](#building-bitcoin)
+- [Building an alternative repository](#building-an-alternative-repository)
+- [Signing externally](#signing-externally)
+- [Uploading signatures](#uploading-signatures)
+
+Create a new VirtualBox VM
+---------------------------
+
+The first step is to create a new Virtual Machine, which will be explained in
+this section.  This VM will be used to do the Gitian builds. In this guide it
+will be explained how to set up the environment, and how to get the builds
+started.
+
+Debian Linux was chosen as the host distribution because it has a lightweight install (in
+contrast to Ubuntu) and is readily available. We here show the steps for
+VirtualBox [1], but any kind of virtualization can be used. You can also install
+on actual hardware instead of using a VM, in this case you can skip this section.
+
+In the VirtualBox GUI click "Create" and choose the following parameters in the wizard:
+
+![](gitian-building/create_vm_page1.png =100x20)
+
+- Type: Linux, Debian (64 bit)
+
+![](gitian-building/create_vm_memsize.png)
+
+- Memory Size: at least 1024MB, anything lower will really slow the build down
+
+![](gitian-building/create_vm_hard_drive.png)
+
+- Hard Drive: Create a virtual hard drive now
+    
+![](gitian-building/create_vm_hard_drive_file_type.png)
+
+- Hard Drive file type: Use the default, VDI (VirtualBox Disk Image) 
+
+![](gitian-building/create_vm_storage_physical_hard_drive.png)
+    
+- Storage on Physical hard drive: Dynamically Allocated 
+    
+![](gitian-building/create_vm_file_location_size.png)
+
+- Disk size: at least 40GB; as low as 20GB *may* be possible, but better to err on the safe side 
+- Push the `Create` button
+
+Get the [Debian 7.4 net installer](http://cdimage.debian.org/debian-cd/7.4.0/amd64/iso-cd/debian-7.4.0-amd64-netinst.iso).
+This DVD image can be validated using a SHA256 hashing tool, for example on
+Unixy OSes by entering the following in a terminal:
+
+    echo "b712a141bc60269db217d3b3e456179bd6b181645f90e4aac9c42ed63de492e9  /home/orion/Downloads/debian-7.4.0-amd64-netinst.iso" | sha256sum -c
+    # (must return OK)
+
+After creating the VM, we need to configure it. 
+
+- Click the `Settings` button, then go to the `Network` tab. Adapter 1 should be attacked to `NAT`.
+
+![](gitian-building/network_settings.png)
+
+- Click `Advanced`, then `Port Forwarding`. We want to set up a port through where we can reach the VM to get files in and out.
+- Create a new rule by clicking the plus icon.
+
+![](gitian-building/port_forwarding_rules.png)
+
+- Set up the new rule the following way:
+  - Name: `SSH`
+  - Protocol: `TCP`
+  - Leave Host IP empty
+  - Host Port: `22222`
+  - Leave Guest IP empty
+  - Guest Port: `22`
+
+- Click `Ok` twice to save.
+
+Then start the VM. On the first launch you will be asked for a CD or DVD image. Choose the downloaded iso.
+
+![](gitian-building/select_startup_disk.png)
+
+[1] https://www.virtualbox.org/
+
+Installing Debian
+------------------
+
+In this section it will be explained how to install Debian on the newly created VM.
+
+- Choose the non-graphical installer.  We do not need the graphical environment, it will only increase installation time and disk usage.
+
+![](gitian-building/debian_install_1_boot_menu.png)
+
+**Note**: Navigation in the Debian installer: To keep a setting at the default
+and proceed, just press `Enter`. To select a different button, press `Tab`.
+
+- Choose locale and keyboard settings (doesn't matter, you can just go with the defaults or select your own information)
+
+![](gitian-building/debian_install_2_select_a_language.png)
+![](gitian-building/debian_install_3_select_location.png)
+![](gitian-building/debian_install_4_configure_keyboard.png)
+
+- The VM will detect network settings using DHCP, this should all proceed automatically
+- Configure the network: 
+  - System name `debian`.
+  - Leave domain name empty.
+
+![](gitian-building/debian_install_5_configure_the_network.png)
+
+- Choose a root password and enter it twice (and remember it for later) 
+
+![](gitian-building/debian_install_6a_set_up_root_password.png)
+
+- Name the new user `debian` (the full name doesn't matter, you can leave it empty) 
+
+![](gitian-building/debian_install_7_set_up_user_fullname.png)
+![](gitian-building/debian_install_8_set_up_username.png)
+
+- Choose a user password and enter it twice (and remember it for later) 
+
+![](gitian-building/debian_install_9_user_password.png)
+
+- The installer will set up the clock using a time server, this process should be automatic
+- Set up the clock: choose a time zone (depends on the locale settings that you picked earlier; specifics don't matter)  
+
+![](gitian-building/debian_install_10_configure_clock.png)
+
+- Disk setup
+  - Partitioning method: Guided - Use the entire disk 
+  
+![](gitian-building/debian_install_11_partition_disks.png)
+
+  - Select disk to partition: SCSI1 (0,0,0) 
+
+![](gitian-building/debian_install_12_choose_disk.png)
+
+  - Partitioning scheme: All files in one partition 
+  
+![](gitian-building/debian_install_13_partition_scheme.png)
+
+  - Finish partitioning and write changes to disk -> *Yes* (`Tab`, `Enter` to select the `Yes` button)
+
+![](gitian-building/debian_install_14_finish.png) 
+![](gitian-building/debian_install_15_write_changes.png)
+
+- The base system will be installed, this will take a minute or so
+- Choose a mirror (any will do) 
+
+![](gitian-building/debian_install_16_choose_a_mirror.png)
+
+- Enter proxy information (unless you are on an intranet, you can leave this empty)
+
+![](gitian-building/debian_install_18_proxy_settings.png)
+
+- Wait a bit while 'Select and install software' runs
+- Participate in popularity contest -> *No*
+- Choose software to install. We need just the base system. 
+
+![](gitian-building/debian_install_19_software_selection.png)
+
+- Make sure only 'SSH server' and 'Standard System Utilities' are checked
+- Uncheck 'Debian Desktop Environment' and 'Print Server'
+
+![](gitian-building/debian_install_20_install_grub.png)
+
+- Install the GRUB boot loader to the master boot record? -> Yes 
+
+![](gitian-building/debian_install_21_finish_installation.png)
+
+- Installation Complete -> *Continue*
+- After installation, the VM will reboot and you will have a working Debian VM. Congratulations!
+
+Connecting to the VM
+----------------------
+
+After the VM has booted you can connect to it using SSH, and files can be copied from and to the VM using a SFTP utility.
+Connect to `localhost`, port `22222` (or the port configured when installing the VM).
+On Windows you can use putty[1] and WinSCP[2].
+
+For example to connect as `root` from a Linux command prompt use
+
+    $ ssh root@localhost -p 22222
+    The authenticity of host '[localhost]:22222 ([127.0.0.1]:22222)' can't be established.
+    ECDSA key fingerprint is 8e:71:f9:5b:62:46:de:44:01:da:fb:5f:34:b5:f2:18.
+    Are you sure you want to continue connecting (yes/no)? yes
+    Warning: Permanently added '[localhost]:22222' (ECDSA) to the list of known hosts.
+    root@localhost's password: (enter root password configured during install)
+    Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64
+    root@debian:~#
+
+Replace `root` with `debian` to log in as user.
+
+[1] http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
+[2] http://winscp.net/eng/index.php
+
+Setting up Debian for gitian building
+--------------------------------------
+
+In this section we will be setting up the Debian installation for Gitian building.
+
+First we need to log in as `root` to set up dependencies and make sure that our
+user can use the sudo command. Type/paste the following in the terminal:
+
+
+```bash
+apt-get install git ruby sudo apt-cacher-ng qemu-utils debootstrap lxc python-cheetah parted kpartx bridge-utils
+adduser debian sudo
+```
+
+When you get a colorful screen with a question about the 'LXC directory', just
+go with the default (`/var/lib/lxc`).
+
+Then set up LXC and the rest with the following is a complex jumble of settings and workarounds:
+
+```bash
+# the version of lxc-start in Debian 7.4 needs to run as root, so make sure
+# that the build script can exectute it without providing a password
+echo "%sudo ALL=NOPASSWD: /usr/bin/lxc-start" > /etc/sudoers.d/gitian-lxc
+# add cgroup for LXC
+echo "cgroup  /sys/fs/cgroup  cgroup  defaults  0   0" >> /etc/fstab
+# make /etc/rc.local script that sets up bridge between guest and host
+echo '#!/bin/sh -e' > /etc/rc.local
+echo 'brctl addbr br0' >> /etc/rc.local
+echo 'ifconfig br0 10.0.3.2/24 up' >> /etc/rc.local
+echo 'exit 0' >> /etc/rc.local
+# make sure that USE_LXC is always set when logging in as debian
+echo 'export USE_LXC=1' >> /home/debian/.profile
+reboot
+```
+
+At the end the VM is rebooted to make sure that the changes take effect.
+
+**Note**: If you're following this guide on a physical system instead of a VirtualBox VM you could use `10.0.2.2` instead
+of `10.0.3.2` in the above `ifconfig` line. This avoids having to patch gitian-builder in next section.
+
+Installing gitian
+------------------
+
+Re-login as the user `debian` that was created during installation.
+The rest of the steps in this guide will be performed as that user.
+
+There is no `python-vm-builder` package in Debian, so we need to install it from source ourselves,
+
+```bash
+wget http://archive.ubuntu.com/ubuntu/pool/universe/v/vm-builder/vm-builder_0.12.4+bzr489.orig.tar.gz
+echo "ec12e0070a007989561bfee5862c89a32c301992dd2771c4d5078ef1b3014f03  vm-builder_0.12.4+bzr489.orig.tar.gz" | sha256sum -c
+# (verification -- must return OK)
+tar -zxvf vm-builder_0.12.4+bzr489.orig.tar.gz
+cd vm-builder-0.12.4+bzr489
+sudo python setup.py install
+cd ..
+```
+
+**Note**: When sudo asks for a password, enter the password for the user *debian* not for *root*.
+
+Clone the git repositories for bitcoin and gitian,
+
+```bash
+git clone https://github.com/devrandom/gitian-builder.git
+git clone https://github.com/bitcoin/bitcoin
+```
+
+We need to change the guest IP range for the gitian builder because otherwise it will
+collide with VirtualBox its NAT IP range. Gitian does not have a way yet to configure
+this, so we need to patch the IPs using `sed`. This is not nice but it will
+have to do for now... (a [pull request
+(#52)](https://github.com/devrandom/gitian-builder/pull/52) to make this
+configurable without patching has been submitted):
+
+```bash
+sed -i 's/10.0.2.2/10.0.3.2/g' gitian-builder/target-bin/bootstrap-fixup
+sed -i 's/10.0.2.5/10.0.3.5/g' gitian-builder/etc/lxc.config.in
+```
+
+*note* After you update the gitian-builder repository, you may need to repeat these manual changes.
+
+Setting up gitian images
+-------------------------
+
+Gitian needs virtual images of the operating system to build in.
+Currently this is Ubuntu Precise for both x86 architectures.
+These images will be copied and used every time that a build is started to
+make sure that the build is deterministic.
+Creating the images will take a while, but only has to be done once.
+
+Execute the following as user `debian`:
+
+```bash
+cd gitian-builder
+bin/make-base-vm --lxc --arch i386 --suite precise
+bin/make-base-vm --lxc --arch amd64 --suite precise
+```
+
+There will be a lot of warnings printed during build of the images. These can be ignored.
+
+**Note**: When sudo asks for a password, enter the password for the user *debian* not for *root*.
+
+Getting and building the inputs
+--------------------------------
+
+In [doc/release-process.md](release-process.md) in the bitcoin repository under 'Fetch and build inputs'.
+you will find a list of `wget` commands that can be executed to get the dependencies.
+
+I needed to add `--no-check-certificate` to the OpenSSL wget line to make it work.
+Likely this is because the ca-certificates in Debian 7.4 is fairly old. This does not create a 
+security issue as the gitian descriptors check integrity of the input archives and refuse to work
+if any one is corrupted.
+
+After downloading the archives, execute the `gbuild` commends to build the dependencies.
+This can take a long time, but only has to be done when the dependencies change, for example
+to upgrade the used version.
+
+**Note**: Do not forget to copy the result from `build/out` to `inputs` after every gbuild command! This will save
+you a lot of time.
+
+At any time you can check the package installation and build progress with
+
+```bash
+tail -f var/install.log
+tail -f var/build.log
+```
+
+To make sure that the output is exactly the same, and that the time, date, locale and
+even the ordering of files in the file system doesn't influence the result,
+some special precautions are taken. This means that the result is expected to
+be the same every time. The expected SHA256 hashes of the intermediate
+inputs (at the time of release 0.9.0) are:
+
+    05fe8e9aef00d295f24a94deef7d3a918af5aeef371ba57fdd5a6acd8c51f6cb  bitcoin-deps-linux32-gitian-r3.zip
+    4227aa9d9fedbb4265b8d10a4f78b7435f34b00a54eb4d662bf78f59c6e70c27  bitcoin-deps-linux64-gitian-r3.zip
+    f29b7d9577417333fb56e023c2977f5726a7c297f320b175a4108cf7cd4c2d29  boost-linux32-1.55.0-gitian-r1.zip
+    88232451c4104f7eb16e469ac6474fd1231bd485687253f7b2bdf46c0781d535  boost-linux64-1.55.0-gitian-r1.zip
+    60dc2d3b61e9c7d5dbe2f90d5955772ad748a47918ff2d8b74e8db9b1b91c909  boost-win32-1.55.0-gitian-r6.zip
+    f65fcaf346bc7b73bc8db3a8614f4f6bee2f61fcbe495e9881133a7c2612a167  boost-win64-1.55.0-gitian-r6.zip
+    0ba0855e1084132d05fd8687c19d8430b91f6c410a9ab7938e4fea650c2b22c8  bitcoin-deps-win32-gitian-r10.zip
+    5f9ffba0c13ddefc1d339f66ab973ea64623c9cc1f9078cb2b145bce86bd28e2  bitcoin-deps-win64-gitian-r10.zip
+    963e3e5e85879010a91143c90a711a5d1d5aba992e38672cdf7b54e42c56b2f1  qt-win32-5.2.0-gitian-r2.zip
+    751c579830d173ef3e6f194e83d18b92ebef6df03289db13ab77a52b6bc86ef0  qt-win64-5.2.0-gitian-r2.zip
+    e2e403e1a08869c7eed4d4293bce13d51ec6a63592918b90ae215a0eceb44cb4  protobuf-win32-2.5.0-gitian-r4.zip
+    a0999037e8b0ef9ade13efd88fee261ba401f5ca910068b7e0cd3262ba667db0  protobuf-win64-2.5.0-gitian-r4.zip
+
+Building Bitcoin
+----------------
+
+To build Bitcoin (for Linux and/or Windows) just follow the steps under 'perform
+gitian builds' in [doc/release-process.md](release-process.md) in the bitcoin repository.
+
+Output from `gbuild` will look something like
+
+    Initialized empty Git repository in /home/debian/gitian-builder/inputs/bitcoin/.git/
+    remote: Reusing existing pack: 35606, done.
+    remote: Total 35606 (delta 0), reused 0 (delta 0)
+    Receiving objects: 100% (35606/35606), 26.52 MiB | 4.28 MiB/s, done.
+    Resolving deltas: 100% (25724/25724), done.
+    From https://github.com/bitcoin/bitcoin
+    ... (new tags, new branch etc)
+    --- Building for precise i386 ---
+    Stopping target if it is up
+    Making a new image copy
+    stdin: is not a tty
+    Starting target
+    Checking if target is up
+    Preparing build environment
+    Updating apt-get repository (log in var/install.log)
+    Installing additional packages (log in var/install.log)
+    Grabbing package manifest
+    stdin: is not a tty
+    Creating build script (var/build-script)
+    lxc-start: Connection refused - inotify event with no name (mask 32768)
+    Running build script (log in var/build.log)
+
+As when building the dependencies, the progress of package installation and building
+can be inspected in `var/install.log` and `var/build.log`.
+
+Building an alternative repository
+-----------------------------------
+
+If you want to do a test build of a pull on github it can be useful to point
+the gitian builder at an alternative repository, using the same descriptors
+and inputs.
+
+For example:
+```bash
+URL=https://github.com/laanwj/bitcoin.git
+COMMIT=2014_03_windows_unicode_path
+./bin/gbuild --commit bitcoin=${COMMIT} --url bitcoin=${URL} ../bitcoin/contrib/gitian-descriptors/gitian-linux.yml
+./bin/gbuild --commit bitcoin=${COMMIT} --url bitcoin=${URL} ../bitcoin/contrib/gitian-descriptors/gitian-win.yml
+```
+
+Signing externally
+-------------------
+
+If you want to do the PGP signing on another device that's possible too; just define `SIGNER` as mentioned
+and follow the steps in the build process as normally.
+
+    gpg: skipped "laanwj": secret key not available
+
+When you execute `gsign` you will get an error from GPG, which can be ignored. Copy the resulting `.assert` files
+in `gitian.sigs` to your signing machine and do
+
+```bash
+    gpg --detach-sign ${VERSION}/${SIGNER}/bitcoin-build.assert
+    gpg --detach-sign ${VERSION}-win/${SIGNER}/bitcoin-build.assert
+```
+
+This will create the `.sig` files that can be committed together with the `.assert` files to assert your
+gitian build.
+
+Uploading signatures
+---------------------
+
+After building and signing you can push your signatures (both the `.assert` and
+`.assert.sig` files) to the
+[bitcoin/gitian.sigs](https://github.com/bitcoin/gitian.sigs/) repository, or
+if not possible create a pull request. You can also mail the files to me
+(laanwj@gmail.com) and I'll commit them.
+