Monero

Copyright (c) 2014-2018 The Monero Project.
Portions Copyright (c) 2012-2013 The Cryptonote developers.

Development resources

• Web: getmonero.org
• Forum: forum.getmonero.org
• Mail: dev@getmonero.org
• GitHub: https://github.com/monero-project/monero
• IRC: #monero-dev on Freenode

Vulnerability response

• Our Vulnerability Response Process encourages responsible disclosure
• We are also available via HackerOne

Announcements

• You can subscribe to an announcement listserv to get critical announcements from the Monero core team. The announcement list can be very helpful for knowing when software updates are needed.

Build

Operating System	Processor	Status
Ubuntu 16.04	i686
Ubuntu 16.04	amd64
Ubuntu 16.04	armv7
Debian Stable	armv8
OSX 10.10	amd64
OSX 10.11	amd64
OSX 10.12	amd64
FreeBSD 11	amd64
DragonFly BSD 4.6	amd64
Windows (MSYS2/MinGW)	i686
Windows (MSYS2/MinGW)	amd64

Coverage

Type	Status
Coverity
Coveralls
License

Introduction

Monero is a private, secure, untraceable, decentralised digital currency. You are your bank, you control your funds, and nobody can trace your transfers unless you allow them to do so.

Privacy: Monero uses a cryptographically sound system to allow you to send and receive funds without your transactions being easily revealed on the blockchain (the ledger of transactions that everyone has). This ensures that your purchases, receipts, and all transfers remain absolutely private by default.

Security: Using the power of a distributed peer-to-peer consensus network, every transaction on the network is cryptographically secured. Individual wallets have a 25 word mnemonic seed that is only displayed once, and can be written down to backup the wallet. Wallet files are encrypted with a passphrase to ensure they are useless if stolen.

Untraceability: By taking advantage of ring signatures, a special property of a certain type of cryptography, Monero is able to ensure that transactions are not only untraceable, but have an optional measure of ambiguity that ensures that transactions cannot easily be tied back to an individual user or computer.

About this project

This is the core implementation of Monero. It is open source and completely free to use without restrictions, except for those specified in the license agreement below. There are no restrictions on anyone creating an alternative implementation of Monero that uses the protocol and network in a compatible manner.

As with many development projects, the repository on Github is considered to be the "staging" area for the latest changes. Before changes are merged into that branch on the main repository, they are tested by individual developers in their own branches, submitted as a pull request, and then subsequently tested by contributors who focus on testing and code reviews. That having been said, the repository should be carefully considered before using it in a production environment, unless there is a patch in the repository for a particular show-stopping issue you are experiencing. It is generally a better idea to use a tagged release for stability.

Anyone is welcome to contribute to Monero's codebase! If you have a fix or code change, feel free to submit it as a pull request directly to the "master" branch. In cases where the change is relatively small or does not affect other parts of the codebase it may be merged in immediately by any one of the collaborators. On the other hand, if the change is particularly large or complex, it is expected that it will be discussed at length either well in advance of the pull request being submitted, or even directly on the pull request.

Supporting the project

Monero is a 100% community-sponsored endeavor. If you want to join our efforts, the easiest thing you can do is support the project financially. Both Monero and Bitcoin donations can be made to donate.getmonero.org if using a client that supports the OpenAlias standard. Alternatively you can send XMR to the Monero donation address via the donate command (type help in the command-line wallet for details).

The Monero donation address is: 44AFFq5kSiGBoZ4NMDwYtN18obc8AemS33DBLWs3H7otXft3XjrpDtQGv7SqSsaBYBb98uNbr2VBBEt7f2wfn3RVGQBEP3A (viewkey: f359631075708155cc3d92a32b75a7d02a5dcf27756707b47a2b31b21c389501)

The Bitcoin donation address is: 1KTexdemPdxSBcG55heUuTjDRYqbC5ZL8H

Core development funding and/or some supporting services are also graciously provided by sponsors:

There are also several mining pools that kindly donate a portion of their fees, a list of them can be found on our Bitcointalk post.

License

See LICENSE.

Contributing

If you want to help out, see CONTRIBUTING for a set of guidelines.

Scheduled software upgrades

Monero uses a fixed-schedule software upgrade (hard fork) mechanism to implement new features. This means that users of Monero (end users and service providers) should run current versions and upgrade their software on a regular schedule. Software upgrades occur during the months of April and October. The required software for these upgrades will be available prior to the scheduled date. Please check the repository prior to this date for the proper Monero software version. Below is the historical schedule and the projected schedule for the next upgrade. Dates are provided in the format YYYY-MM-DD.

Software upgrade block height	Date	Fork version	Minimum Monero version	Recommended Monero version	Details
1009827	2016-03-22	v2	v0.9.4	v0.9.4	Allow only >= ringsize 3, blocktime = 120 seconds, fee-free blocksize 60 kb
1141317	2016-09-21	v3	v0.9.4	v0.10.0	Splits coinbase into denominations
1220516	2017-01-05	v4	v0.10.1	v0.10.2.1	Allow normal and RingCT transactions
1288616	2017-04-15	v5	v0.10.3.0	v0.10.3.1	Adjusted minimum blocksize and fee algorithm
1400000	2017-09-16	v6	v0.11.0.0	v0.11.0.0	Allow only RingCT transactions, allow only >= ringsize 5
1546000	2018-04-06	v7	v0.12.0.0	v0.12.0.0	Cryptonight variant 1, ringsize >= 7, sorted inputs
XXXXXXX	2018-10-XX	XX	XXXXXXXXX	XXXXXXXXX	X

X's indicate that these details have not been determined as of commit date.

Release staging schedule and protocol

Approximately three months prior to a scheduled software upgrade, a branch from Master will be created with the new release version tag. Pull requests that address bugs should then be made to both Master and the new release branch. Pull requests that require extensive review and testing (generally, optimizations and new features) should not be made to the release branch.

Installing Monero from a package

Packages are available for

• Ubuntu and snap supported systems, via a community contributed build.

  snap install monero --beta

Installing a snap is very quick. Snaps are secure. They are isolated with all of their dependencies. Snaps also auto update when a new version is released.

• Arch Linux (via AUR):

  • Stable release: monero
  • Bleeding edge: monero-git

• Void Linux:

  xbps-install -S monero

• GuixSD

    guix package -i monero
  

• OS X via Homebrew

    brew tap sammy007/cryptonight
    brew install monero --build-from-source
  

• Docker

    # Build using all available cores
    docker build -t monero .
  
    # or build using a specific number of cores (reduce RAM requirement)
    docker build --build-arg NPROC=1 -t monero .
  
    # either run in foreground
    docker run -it -v /monero/chain:/root/.bitmonero -v /monero/wallet:/wallet -p 18080:18080 monero
  
    # or in background
    docker run -it -d -v /monero/chain:/root/.bitmonero -v /monero/wallet:/wallet -p 18080:18080 monero
  

Packaging for your favorite distribution would be a welcome contribution!

Compiling Monero from source

Dependencies

The following table summarizes the tools and libraries required to build. A few of the libraries are also included in this repository (marked as "Vendored"). By default, the build uses the library installed on the system, and ignores the vendored sources. However, if no library is found installed on the system, then the vendored source will be built and used. The vendored sources are also used for statically-linked builds because distribution packages often include only shared library binaries (.so) but not static library archives (.a).

Dep	Min. version	Vendored	Debian/Ubuntu pkg	Arch pkg	Fedora	Optional	Purpose
GCC	4.7.3	NO	build-essential	base-devel	gcc	NO
CMake	3.0.0	NO	cmake	cmake	cmake	NO
pkg-config	any	NO	pkg-config	base-devel	pkgconf	NO
Boost	1.58	NO	libboost-all-dev	boost	boost-devel	NO	C++ libraries
OpenSSL	basically any	NO	libssl-dev	openssl	openssl-devel	NO	sha256 sum
libzmq	3.0.0	NO	libzmq3-dev	zeromq	cppzmq-devel	NO	ZeroMQ library
libunbound	1.4.16	YES	libunbound-dev	unbound	unbound-devel	NO	DNS resolver
libsodium	?	NO	libsodium-dev	?	libsodium-devel	NO	libsodium
libminiupnpc	2.0	YES	libminiupnpc-dev	miniupnpc	miniupnpc-devel	YES	NAT punching
libunwind	any	NO	libunwind8-dev	libunwind	libunwind-devel	YES	Stack traces
liblzma	any	NO	liblzma-dev	xz	xz-devel	YES	For libunwind
libreadline	6.3.0	NO	libreadline6-dev	readline	readline-devel	YES	Input editing
ldns	1.6.17	NO	libldns-dev	ldns	ldns-devel	YES	SSL toolkit
expat	1.1	NO	libexpat1-dev	expat	expat-devel	YES	XML parsing
GTest	1.5	YES	libgtest-dev^	gtest	gtest-devel	YES	Test suite
Doxygen	any	NO	doxygen	doxygen	doxygen	YES	Documentation
Graphviz	any	NO	graphviz	graphviz	graphviz	YES	Documentation

[^] On Debian/Ubuntu libgtest-dev only includes sources and headers. You must build the library binary manually. This can be done with the following command sudo apt-get install libgtest-dev && cd /usr/src/gtest && sudo cmake . && sudo make && sudo mv libg* /usr/lib/

Cloning the repository

Clone recursively to pull-in needed submodule(s):

$ git clone --recursive https://github.com/monero-project/monero

If you already have a repo cloned, initialize and update:

$ cd monero && git submodule init && git submodule update

Build instructions

Monero uses the CMake build system and a top-level Makefile that invokes cmake commands as needed.

On Linux and OS X

• Install the dependencies

• Change to the root of the source code directory and build:

    cd monero
    make
  

  Optional: If your machine has several cores and enough memory, enable parallel build by running make -j<number of threads> instead of make. For this to be worthwhile, the machine should have one core and about 2GB of RAM available per thread.

  Note: If cmake can not find zmq.hpp file on OS X, installing zmq.hpp from https://github.com/zeromq/cppzmq to /usr/local/include should fix that error.

• The resulting executables can be found in build/release/bin

• Add PATH="$PATH:$HOME/monero/build/release/bin" to .profile

• Run Monero with monerod --detach

• Optional: build and run the test suite to verify the binaries:

    make release-test
  

  NOTE: core_tests test may take a few hours to complete.

• Optional: to build binaries suitable for debugging:

     make debug
  

• Optional: to build statically-linked binaries:

     make release-static
  

Dependencies need to be built with -fPIC. Static libraries usually aren't, so you may have to build them yourself with -fPIC. Refer to their documentation for how to build them.

• Optional: build documentation in doc/html (omit HAVE_DOT=YES if graphviz is not installed):

    HAVE_DOT=YES doxygen Doxyfile
  

On the Raspberry Pi

Tested on a Raspberry Pi Zero with a clean install of minimal Raspbian Stretch (2017-09-07 or later) from https://www.raspberrypi.org/downloads/raspbian/. If you are using Raspian Jessie, please see note in the following section.

• apt-get update && apt-get upgrade to install all of the latest software

• Install the dependencies for Monero from the 'Debian' column in the table above.

• Increase the system swap size:

	sudo /etc/init.d/dphys-swapfile stop  
	sudo nano /etc/dphys-swapfile  
	CONF_SWAPSIZE=1024  
	sudo /etc/init.d/dphys-swapfile start  

• Clone monero and checkout most recent release version:

        git clone https://github.com/monero-project/monero.git
	cd monero
	git checkout tags/v0.11.1.0

• Build:

        make release

• Wait 4-6 hours

• The resulting executables can be found in build/release/bin

• Add PATH="$PATH:$HOME/monero/build/release/bin" to .profile

• Run Monero with monerod --detach

• You may wish to reduce the size of the swap file after the build has finished, and delete the boost directory from your home directory

Note for Raspbian Jessie users:

If you are using the older Raspbian Jessie image, compiling Monero is a bit more complicated. The version of Boost available in the Debian Jessie repositories is too old to use with Monero, and thus you must compile a newer version yourself. The following explains the extra steps, and has been tested on a Raspberry Pi 2 with a clean install of minimal Raspbian Jessie.

• As before, apt-get update && apt-get upgrade to install all of the latest software, and increase the system swap size

	sudo /etc/init.d/dphys-swapfile stop  
	sudo nano /etc/dphys-swapfile  
	CONF_SWAPSIZE=1024  
	sudo /etc/init.d/dphys-swapfile start  

• Then, install the dependencies for Monero except libunwind and libboost-all-dev

• Install the latest version of boost (this may first require invoking apt-get remove --purge libboost* to remove a previous version if you're not using a clean install):

	cd  
	wget https://sourceforge.net/projects/boost/files/boost/1.64.0/boost_1_64_0.tar.bz2  
	tar xvfo boost_1_64_0.tar.bz2  
	cd boost_1_64_0  
	./bootstrap.sh  
	sudo ./b2  

• Wait ~8 hours

	sudo ./bjam install

• Wait ~4 hours

• From here, follow the general Raspberry Pi instructions from the "Clone monero and checkout most recent release version" step.

On Windows:

Binaries for Windows are built on Windows using the MinGW toolchain within MSYS2 environment. The MSYS2 environment emulates a POSIX system. The toolchain runs within the environment and cross-compiles binaries that can run outside of the environment as a regular Windows application.

Preparing the build environment

• Download and install the MSYS2 installer, either the 64-bit or the 32-bit package, depending on your system.

• Open the MSYS shell via the MSYS2 Shell shortcut

• Update packages using pacman:

    pacman -Syuu  
  

• Exit the MSYS shell using Alt+F4

• Edit the properties for the MSYS2 Shell shortcut changing "msys2_shell.bat" to "msys2_shell.cmd -mingw64" for 64-bit builds or "msys2_shell.cmd -mingw32" for 32-bit builds

• Restart MSYS shell via modified shortcut and update packages again using pacman:

    pacman -Syuu  
  

• Install dependencies:

  To build for 64-bit Windows:

    pacman -S mingw-w64-x86_64-toolchain make mingw-w64-x86_64-cmake mingw-w64-x86_64-boost mingw-w64-x86_64-openssl mingw-w64-x86_64-zeromq mingw-w64-x86_64-libsodium
  

  To build for 32-bit Windows:

    pacman -S mingw-w64-i686-toolchain make mingw-w64-i686-cmake mingw-w64-i686-boost mingw-w64-i686-openssl mingw-w64-i686-zeromq mingw-w64-i686-libsodium
  

• Open the MingW shell via MinGW-w64-Win64 Shell shortcut on 64-bit Windows or MinGW-w64-Win64 Shell shortcut on 32-bit Windows. Note that if you are running 64-bit Windows, you will have both 64-bit and 32-bit MinGW shells.

Building

• If you are on a 64-bit system, run:

    make release-static-win64
  

• If you are on a 32-bit system, run:

    make release-static-win32
  

• The resulting executables can be found in build/release/bin

On FreeBSD:

The project can be built from scratch by following instructions for Linux above. If you are running monero in a jail you need to add the flag: allow.sysvipc=1 to your jail configuration, otherwise lmdb will throw the error message: Failed to open lmdb environment: Function not implemented.

We expect to add Monero into the ports tree in the near future, which will aid in managing installations using ports or packages.

On OpenBSD:

OpenBSD < 6.2

This has been tested on OpenBSD 5.8.

You will need to add a few packages to your system. pkg_add db cmake gcc gcc-libs g++ miniupnpc gtest.

The doxygen and graphviz packages are optional and require the xbase set.

The Boost package has a bug that will prevent librpc.a from building correctly. In order to fix this, you will have to Build boost yourself from scratch. Follow the directions here (under "Building Boost"): https://github.com/bitcoin/bitcoin/blob/master/doc/build-openbsd.md

You will have to add the serialization, date_time, and regex modules to Boost when building as they are needed by Monero.

To build: env CC=egcc CXX=eg++ CPP=ecpp DEVELOPER_LOCAL_TOOLS=1 BOOST_ROOT=/path/to/the/boost/you/built make release-static-64

OpenBSD >= 6.2

You will need to add a few packages to your system. pkg_add cmake miniupnpc zeromq libiconv.

The doxygen and graphviz packages are optional and require the xbase set.

Build the Boost library using clang. This guide is derived from: https://github.com/bitcoin/bitcoin/blob/master/doc/build-openbsd.md

We assume you are compiling with a non-root user and you have doas enabled.

Note: do not use the boost package provided by OpenBSD, as we are installing boost to /usr/local.

# Create boost building directory
mkdir ~/boost
cd ~/boost

# Fetch boost source
ftp -o boost_1_64_0.tar.bz2 https://netcologne.dl.sourceforge.net/project/boost/boost/1.64.0/boost_1_64_0.tar.bz2 

# MUST output: (SHA256) boost_1_64_0.tar.bz2: OK
echo "7bcc5caace97baa948931d712ea5f37038dbb1c5d89b43ad4def4ed7cb683332 boost_1_64_0.tar.bz2" | sha256 -c
tar xfj boost_1_64_0.tar.bz2

# Fetch and apply boost patches, required for OpenBSD
ftp -o boost_test_impl_execution_monitor_ipp.patch https://raw.githubusercontent.com/openbsd/ports/bee9e6df517077a7269ff0dfd57995f5c6a10379/devel/boost/patches/patch-boost_test_impl_execution_monitor_ipp
ftp -o boost_config_platform_bsd_hpp.patch https://raw.githubusercontent.com/openbsd/ports/90658284fb786f5a60dd9d6e8d14500c167bdaa0/devel/boost/patches/patch-boost_config_platform_bsd_hpp

# MUST output: (SHA256) boost_config_platform_bsd_hpp.patch: OK
echo "1f5e59d1154f16ee1e0cc169395f30d5e7d22a5bd9f86358f738b0ccaea5e51d boost_config_platform_bsd_hpp.patch" | sha256 -c
# MUST output: (SHA256) boost_test_impl_execution_monitor_ipp.patch: OK
echo "30cec182a1437d40c3e0bd9a866ab5ddc1400a56185b7e671bb3782634ed0206 boost_test_impl_execution_monitor_ipp.patch" | sha256 -c

cd boost_1_64_0
patch -p0 < ../boost_test_impl_execution_monitor_ipp.patch
patch -p0 < ../boost_config_platform_bsd_hpp.patch

# Start building boost
echo 'using clang : : c++ : <cxxflags>"-fvisibility=hidden -fPIC" <linkflags>"" <archiver>"ar" <striper>"strip"  <ranlib>"ranlib" <rc>"" : ;' > user-config.jam
./bootstrap.sh --without-icu --with-libraries=chrono,filesystem,program_options,system,thread,test,date_time,regex,serialization,locale --with-toolset=clang
./b2 toolset=clang cxxflags="-stdlib=libc++" linkflags="-stdlib=libc++" -sICONV_PATH=/usr/local
doas ./b2 -d0 runtime-link=shared threadapi=pthread threading=multi link=static variant=release --layout=tagged --build-type=complete --user-config=user-config.jam -sNO_BZIP2=1 -sICONV_PATH=/usr/local --prefix=/usr/local install

Build cppzmq

Build the cppzmq bindings.

We assume you are compiling with a non-root user and you have doas enabled.

# Create cppzmq building directory
mkdir ~/cppzmq
cd ~/cppzmq

# Fetch cppzmq source
ftp -o cppzmq-4.2.3.tar.gz https://github.com/zeromq/cppzmq/archive/v4.2.3.tar.gz

# MUST output: (SHA256) cppzmq-4.2.3.tar.gz: OK
echo "3e6b57bf49115f4ae893b1ff7848ead7267013087dc7be1ab27636a97144d373 cppzmq-4.2.3.tar.gz" | sha256 -c
tar xfz cppzmq-4.2.3.tar.gz

# Start building cppzmq
cd cppzmq-4.2.3
mkdir build
cd build
cmake ..
doas make install

Build monero: env DEVELOPER_LOCAL_TOOLS=1 BOOST_ROOT=/usr/local make release-static

On Solaris:

The default Solaris linker can't be used, you have to install GNU ld, then run cmake manually with the path to your copy of GNU ld:

    mkdir -p build/release
    cd build/release
    cmake -DCMAKE_LINKER=/path/to/ld -D CMAKE_BUILD_TYPE=Release ../..
    cd ../..

Then you can run make as usual.

On Linux for Android (using docker):

    # Build image (select android64.Dockerfile for aarch64)
    cd utils/build_scripts/ && docker build -f android32.Dockerfile -t monero-android .
    # Create container
    docker create -it --name monero-android monero-android bash
    # Get binaries
    docker cp monero-android:/opt/android/monero/build/release/bin .

Building portable statically linked binaries

By default, in either dynamically or statically linked builds, binaries target the specific host processor on which the build happens and are not portable to other processors. Portable binaries can be built using the following targets:

• make release-static-linux-x86_64 builds binaries on Linux on x86_64 portable across POSIX systems on x86_64 processors
• make release-static-linux-i686 builds binaries on Linux on x86_64 or i686 portable across POSIX systems on i686 processors
• make release-static-linux-armv8 builds binaries on Linux portable across POSIX systems on armv8 processors
• make release-static-linux-armv7 builds binaries on Linux portable across POSIX systems on armv7 processors
• make release-static-linux-armv6 builds binaries on Linux portable across POSIX systems on armv6 processors
• make release-static-win64 builds binaries on 64-bit Windows portable across 64-bit Windows systems
• make release-static-win32 builds binaries on 64-bit or 32-bit Windows portable across 32-bit Windows systems

Running monerod

The build places the binary in bin/ sub-directory within the build directory from which cmake was invoked (repository root by default). To run in foreground:

./bin/monerod

To list all available options, run ./bin/monerod --help. Options can be specified either on the command line or in a configuration file passed by the --config-file argument. To specify an option in the configuration file, add a line with the syntax argumentname=value, where argumentname is the name of the argument without the leading dashes, for example log-level=1.

To run in background:

./bin/monerod --log-file monerod.log --detach

To run as a systemd service, copy monerod.service to /etc/systemd/system/ and monerod.conf to /etc/. The example service assumes that the user monero exists and its home is the data directory specified in the example config.

If you're on Mac, you may need to add the --max-concurrency 1 option to monero-wallet-cli, and possibly monerod, if you get crashes refreshing.

Internationalization

See README.i18n.md.

Using Tor

While Monero isn't made to integrate with Tor, it can be used wrapped with torsocks, by setting the following configuration parameters and environment variables:

• --p2p-bind-ip 127.0.0.1 on the command line or p2p-bind-ip=127.0.0.1 in monerod.conf to disable listening for connections on external interfaces.
• --no-igd on the command line or no-igd=1 in monerod.conf to disable IGD (UPnP port forwarding negotiation), which is pointless with Tor.
• DNS_PUBLIC=tcp or DNS_PUBLIC=tcp://x.x.x.x where x.x.x.x is the IP of the desired DNS server, for DNS requests to go over TCP, so that they are routed through Tor. When IP is not specified, monerod uses the default list of servers defined in src/common/dns_utils.cpp.
• TORSOCKS_ALLOW_INBOUND=1 to tell torsocks to allow monerod to bind to interfaces to accept connections from the wallet. On some Linux systems, torsocks allows binding to localhost by default, so setting this variable is only necessary to allow binding to local LAN/VPN interfaces to allow wallets to connect from remote hosts. On other systems, it may be needed for local wallets as well.
• Do NOT pass --detach when running through torsocks with systemd, (see utils/systemd/monerod.service for details).

Example command line to start monerod through Tor:

DNS_PUBLIC=tcp torsocks monerod --p2p-bind-ip 127.0.0.1 --no-igd

Using Tor on Tails

TAILS ships with a very restrictive set of firewall rules. Therefore, you need to add a rule to allow this connection too, in addition to telling torsocks to allow inbound connections. Full example:

sudo iptables -I OUTPUT 2 -p tcp -d 127.0.0.1 -m tcp --dport 18081 -j ACCEPT
DNS_PUBLIC=tcp torsocks ./monerod --p2p-bind-ip 127.0.0.1 --no-igd --rpc-bind-ip 127.0.0.1 \
    --data-dir /home/amnesia/Persistent/your/directory/to/the/blockchain

Debugging

This section contains general instructions for debugging failed installs or problems encountered with Monero. First ensure you are running the latest version built from the Github repo.

Obtaining stack traces and core dumps on Unix systems

We generally use the tool gdb (GNU debugger) to provide stack trace functionality, and ulimit to provide core dumps in builds which crash or segfault.

• To use gdb in order to obtain a stack trace for a build that has stalled:

Run the build.

Once it stalls, enter the following command:

gdb /path/to/monerod `pidof monerod` 

Type thread apply all bt within gdb in order to obtain the stack trace

• If however the core dumps or segfaults:

Enter ulimit -c unlimited on the command line to enable unlimited filesizes for core dumps

Enter echo core | sudo tee /proc/sys/kernel/core_pattern to stop cores from being hijacked by other tools

Run the build.

When it terminates with an output along the lines of "Segmentation fault (core dumped)", there should be a core dump file in the same directory as monerod. It may be named just core, or core.xxxx with numbers appended.

You can now analyse this core dump with gdb as follows:

gdb /path/to/monerod /path/to/dumpfile

Print the stack trace with bt

• To run monero within gdb:

Type gdb /path/to/monerod

Pass command-line options with --args followed by the relevant arguments

Type run to run monerod

Analysing memory corruption

We use the tool valgrind for this.

Run with valgrind /path/to/monerod. It will be slow.

LMDB

Instructions for debugging suspected blockchain corruption as per @HYC

There is an mdb_stat command in the LMDB source that can print statistics about the database but it's not routinely built. This can be built with the following command:

cd ~/monero/external/db_drivers/liblmdb && make

The output of mdb_stat -ea <path to blockchain dir> will indicate inconsistencies in the blocks, block_heights and block_info table.

The output of mdb_dump -s blocks <path to blockchain dir> and mdb_dump -s block_info <path to blockchain dir> is useful for indicating whether blocks and block_info contain the same keys.

These records are dumped as hex data, where the first line is the key and the second line is the data.