UNIX BUILD NOTES

Some notes on how to build Bitcoin Core in Unix.

(for OpenBSD specific instructions, see build-openbsd.md)

Note

Always use absolute paths to configure and compile bitcoin and the dependencies, for example, when specifying the path of the dependency:

../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIX

Here BDB_PREFIX must be an absolute path - it is defined using $(pwd) which ensures the usage of the absolute path.

To Build

./autogen.sh./configuremakemake install # optional

This will build bitcoin-qt as well if the dependencies are met.

Dependencies

These dependencies are required:

LibraryPurposeDescriptionlibsslCryptoRandom Number Generation, Elliptic Curve CryptographylibboostUtilityLibrary for threading, data structures, etclibeventNetworkingOS independent asynchronous networking

Optional dependencies:

LibraryPurposeDescriptionminiupnpcUPnP SupportFirewall-jumping supportlibdb4.8Berkeley DBWallet storage (only needed when wallet enabled)qtGUIGUI toolkit (only needed when GUI enabled)protobufPayments in GUIData interchange format used for payment protocol (only needed when GUI enabled)libqrencodeQR codes in GUIOptional for generating QR codes (only needed when GUI enabled)univalueUtilityJSON parsing and encoding (bundled version will be used unless --with-system-univalue passed to configure)libzmq3ZMQ notificationOptional, allows generating ZMQ notifications (requires ZMQ version >= 4.x)

For the versions used in the release, see release-process.md under Fetch and build inputs.

Memory Requirements

C++ compilers are memory-hungry. It is recommended to have at least 1.5 GB of memory available when compiling Bitcoin Core. On systems with less, gcc can be tuned to conserve memory with additional CXXFLAGS:

./configure CXXFLAGS="--param ggc-min-expand=1 --param ggc-min-heapsize=32768"

Dependency Build Instructions: Ubuntu & Debian

Build requirements:

sudo apt-get install build-essential libtool autotools-dev automake pkg-config libssl-dev libevent-dev bsdmainutils

Options when installing required Boost library files:

1. On at least Ubuntu 14.04+ and Debian 7+ there are generic names for the individual boost development packages, so the following can be used to only install necessary parts of boost:

   sudo apt-get install libboost-system-dev libboost-filesystem-dev libboost-chrono-dev libboost-program-options-dev libboost-test-dev libboost-thread-dev

2. If that doesn't work, you can install all boost development packages with:

   sudo apt-get install libboost-all-dev

BerkeleyDB is required for the wallet. db4.8 packages are available here. You can add the repository and install using the following commands:

sudo add-apt-repository ppa:bitcoin/bitcoinsudo apt-get updatesudo apt-get install libdb4.8-dev libdb4.8++-dev

Ubuntu and Debian have their own libdb-dev and libdb++-dev packages, but these will install BerkeleyDB 5.1 or later, which break binary wallet compatibility with the distributed executables which are based on BerkeleyDB 4.8. If you do not care about wallet compatibility, pass --with-incompatible-bdb to configure.

See the section "Disable-wallet mode" to build Bitcoin Core without wallet.

Optional:

sudo apt-get install libminiupnpc-dev (see --with-miniupnpc and --enable-upnp-default)

ZMQ dependencies:

sudo apt-get install libzmq3-dev (provides ZMQ API 4.x)

Dependencies for the GUI: Ubuntu & Debian

If you want to build Bitcoin-Qt, make sure that the required packages for Qt development are installed. Either Qt 5 or Qt 4 are necessary to build the GUI. If both Qt 4 and Qt 5 are installed, Qt 5 will be used. Pass --with-gui=qt4 to configure to choose Qt4. To build without GUI pass --without-gui.

To build with Qt 5 (recommended) you need the following:

sudo apt-get install libqt5gui5 libqt5core5a libqt5dbus5 qttools5-dev qttools5-dev-tools libprotobuf-dev protobuf-compiler

Alternatively, to build with Qt 4 you need the following:

sudo apt-get install libqt4-dev libprotobuf-dev protobuf-compiler

libqrencode (optional) can be installed with:

sudo apt-get install libqrencode-dev

Once these are installed, they will be found by configure and a bitcoin-qt executable will be built by default.

Notes

The release is built with GCC and then "strip bitcoind" to strip the debug symbols, which reduces the executable size by about 90%.

miniupnpc

miniupnpc may be used for UPnP port mapping. It can be downloaded from here. UPnP support is compiled in and turned off by default. See the configure options for upnp behavior desired:

--without-miniupnpc      No UPnP support miniupnp not required--disable-upnp-default   (the default) UPnP support turned off by default at runtime--enable-upnp-default    UPnP support turned on by default at runtime

Berkeley DB

It is recommended to use Berkeley DB 4.8. If you have to build it yourself:

BITCOIN_ROOT=$(pwd)# Pick some path to install BDB to, here we create a directory within the bitcoin directoryBDB_PREFIX="${BITCOIN_ROOT}/db4"mkdir -p $BDB_PREFIX# Fetch the source and verify that it is not tampered withwget 'http://download.oracle.com/berkeley-db/db-4.8.30.NC.tar.gz'echo '12edc0df75bf9abd7f82f821795bcee50f42cb2e5f76a6a281b85732798364ef  db-4.8.30.NC.tar.gz' | sha256sum -c# -> db-4.8.30.NC.tar.gz: OKtar -xzvf db-4.8.30.NC.tar.gz# Build the library and install to our prefixcd db-4.8.30.NC/build_unix/#  Note: Do a static build so that it can be embedded into the executable, instead of having to find a .so at runtime../dist/configure --enable-cxx --disable-shared --with-pic --prefix=$BDB_PREFIXmake install# Configure Bitcoin Core to use our own-built instance of BDBcd $BITCOIN_ROOT./autogen.sh./configure LDFLAGS="-L${BDB_PREFIX}/lib/" CPPFLAGS="-I${BDB_PREFIX}/include/" # (other args...)

Note: You only need Berkeley DB if the wallet is enabled (see the section Disable-Wallet mode below).

Boost

If you need to build Boost yourself:

sudo su./bootstrap.sh./bjam install

Security

To help make your bitcoin installation more secure by making certain attacks impossible to exploit even if a vulnerability is found, binaries are hardened by default. This can be disabled with:

Hardening Flags:

./configure --enable-hardening./configure --disable-hardening

Hardening enables the following features:

• Position Independent Executable Build position independent code to take advantage of Address Space Layout Randomization offered by some kernels. Attackers who can cause execution of code at an arbitrary memory location are thwarted if they don't know where anything useful is located. The stack and heap are randomly located by default but this allows the code section to be randomly located as well.

  On an AMD64 processor where a library was not compiled with -fPIC, this will cause an error such as: "relocation R_X86_64_32 against `......' can not be used when making a shared object;"

  To test that you have built PIE executable, install scanelf, part of paxutils, and use:

  scanelf -e ./bitcoin

  The output should contain:

  TYPE ET_DYN

• Non-executable Stack If the stack is executable then trivial stack based buffer overflow exploits are possible if vulnerable buffers are found. By default, bitcoin should be built with a non-executable stack but if one of the libraries it uses asks for an executable stack or someone makes a mistake and uses a compiler extension which requires an executable stack, it will silently build an executable without the non-executable stack protection.

  To verify that the stack is non-executable after compiling use: scanelf -e ./bitcoin

  the output should contain: STK/REL/PTL RW- R-- RW-

  The STK RW- means that the stack is readable and writeable but not executable.

Disable-wallet mode

When the intention is to run only a P2P node without a wallet, bitcoin may be compiled in disable-wallet mode with:

./configure --disable-wallet

In this case there is no dependency on Berkeley DB 4.8.

Mining is also possible in disable-wallet mode, but only using the getblocktemplate RPC call not getwork.

Additional Configure Flags

A list of additional configure flags can be displayed with:

./configure --help

ARM Cross-compilation

These steps can be performed on, for example, an Ubuntu VM. The depends system will also work on other Linux distributions, however the commands for installing the toolchain will be different.

First install the toolchain:

sudo apt-get install g++-arm-linux-gnueabihf

To build executables for ARM:

cd dependsmake HOST=arm-linux-gnueabihf NO_QT=1cd .../configure --prefix=$PWD/depends/arm-linux-gnueabihf --enable-glibc-back-compat --enable-reduce-exports LDFLAGS=-static-libstdc++make

For further documentation on the depends system see README.md in the depends directory.