uPlexa

Copyright (c) 2018 uPlexa.
Portions Copyright (c) 2012-2013 The Cryptonote developers.

Development resources

• Web: uplexa.com
• Mail: [email protected]
• GitHub: https://github.com/uPlexa/uplexa
• Discord: (https://discord.gg/a7mAQwJ)

Vulnerability response

• Our Vulnerability Response Process encourages responsible disclosure. Please send a message to [email protected] with "vuln" somewhere within the title, or reach out to QuantumL3aper in Discord.

Announcements

• Subscribe to our Reddit for important announcements regarding uPlexa (https://www.reddit.com/r/uPlexa/)

Build

Coverage

Type	Status
License

Introduction

uPlexa 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: uPlexa 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, uPlexa 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 uPlexa. 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 uPlexa 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 uPlexa'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.

License

See LICENSE.

Contributing

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

Scheduled software upgrades

uPlexa uses a fixed-schedule software upgrade (hard fork) mechanism to implement new features. This means that users of uPlexa (end users and service providers) should run current versions and upgrade their software on a regular schedule. Software upgrades occur during the months of March and August. 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 uPlexa 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 uPlexa version	Recommended uPlexa version	Details
2	2018-10-23	v9	v0.1.9.0	v0.1.9.0	CryptoNight-UPX, BulletProof
52279	2018-11-25	v10	v0.2.0.0	v0.2.0.0	120s block times, LWMA difficulty
162,090	2019-04-29	v11	v0.2.1.0	v0.2.1.0	ALGO: UPXTWO (Crazy fast)
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.

Compiling uPlexa 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	3.5	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
OpenPGM	?	NO	libpgm-dev	libpgm	openpgm-devel	NO	For ZeroMQ
libunbound	1.4.16	YES	libunbound-dev	unbound	unbound-devel	NO	DNS resolver
libsodium	?	NO	libsodium-dev	libsodium	libsodium-devel	NO	cryptography
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/

Debian / Ubuntu one liner for all dependencies
sudo apt update && sudo apt install build-essential cmake pkg-config libboost-all-dev libssl-dev libzmq3-dev libunbound-dev libsodium-dev libunwind8-dev liblzma-dev libreadline6-dev libldns-dev libexpat1-dev doxygen graphviz libpgm-dev

Cloning the repository

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

$ git clone --recursive https://github.com/uPlexa/uplexa

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

$ cd uplexa && git submodule init && git submodule update

Build instructions

uPlexa 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, change to the most recent release branch, and build:

    cd uplexa
    git checkout master
    make release
  

  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.

  Note: The instructions above will compile the most stable release of the uPlexa software. If you would like to use and test the most recent software, use git checkout master. The master branch may contain updates that are both unstable and incompatible with release software, though testing is always encouraged.

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

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

• Run uPlexa with uplexad --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 uPlexa 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 uplexa and checkout most recent release version:

        git clone https://github.com/uPlexa/uplexa.git
	cd uplexa
	git checkout tags/v0.2.1.0

• Build:

        make release

• Wait 4-6 hours

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

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

• Run uPlexa with uplexad --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 uPlexa is a bit more complicated. The version of Boost available in the Debian Jessie repositories is too old to use with uPlexa, 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 uPlexa 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 cxxflags=-fPIC cflags=-fPIC -a install

• Wait ~4 hours

• From here, follow the general Raspberry Pi instructions from the "Clone uplexa 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 mingw-w64-x86_64-hidapi
  

  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 mingw-w64-i686-hidapi
  

• 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.

Cloning

• To git clone, run:

    git clone --recursive https://github.com/uPlexa/uplexa.git
  

Building

• Change to the cloned directory, run:

    cd uplexa
  

• If you would like a specific version/tag, do a git checkout for that version. eg. 'v0.2.1.0'. If you dont care about the version and just want binaries from master, skip this step:

    git checkout master
  

• 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

• Optional: to build Windows binaries suitable for debugging on a 64-bit system, run:

    make debug-static-win64
  

• Optional: to build Windows binaries suitable for debugging on a 32-bit system, run:

    make debug-static-win32
  

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

On FreeBSD:

The project can be built from scratch by following instructions for Linux above. If you are running uplexa 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 uPlexa 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++ 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 uPlexa.

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 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 uplexa: 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 (for ARM 32-bit)
    docker build -f utils/build_scripts/android32.Dockerfile -t uplexa-android .
    # Build image (for ARM 64-bit)
    docker build -f utils/build_scripts/android64.Dockerfile -t uplexa-android .
    # Create container
    docker create -it --name uplexa-android uplexa-android bash
    # Get binaries
    docker cp uplexa-android:/src/build/release/bin .

Building portable statically linked binaries (Cross Compiling)

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

Installing uPlexa from a package

DISCLAIMER: These packages are not part of this repository or maintained by this project's contributors, and as such, do not go through the same review process to ensure their trustworthiness and security.

Packages are available for

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

  snap install uplexa --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: uplexa
  • Bleeding edge: uplexa-git

• Void Linux:

    xbps-install -S uplexa
  

• GuixSD

    guix package -i uplexa
  

• Docker

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

• The build needs 3 GB space.

• Wait one hour or more

Packaging for your favorite distribution would be a welcome contribution!

You can also cross-compile binaries on linux for windows and macos with the depends system. Go to contrib/depends and type:

• make HOST=x86_64-linux-gnu for 64-bit linux binaries.
• make HOST=x86_64-w64-mingw32 for 64-bit windows binaries. Requires: python3 nsis g++-mingw-w64-x86-64 wine1.6 bc
• make HOST=x86_64-apple-darwin11 for darwin binaries. Requires: cmake imagemagick libcap-dev librsvg2-bin libz-dev libbz2-dev libtiff-tools python-dev
• make HOST=i686-linux-gnu for 32-bit linux binaries. Requires: g++-multilib bc
• make HOST=i686-w64-mingw32 for 32-bit windows binaries. Requires: python3 nsis g++-mingw-w64-i686
• make HOST=arm-linux-gnueabihf for armv6 binaries. Requires: g++-arm-linux-gnueabihf

The required packages are the names for each toolchain on apt. Depending on your distro, they may have different names. Then go back to the source dir and type for example for windows 64bit:

• cmake -DCMAKE_TOOLCHAIN_FILE=`pwd`/contrib/depends/x86_64-w64-mingw32

Using depends might also be easier to compile uplexa on windows than using msys. Activate windows subsystem for linux (for example ubuntu) install the apt build-essentials and follow the depends steps as depicted above.

Running uplexad

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/uplexad

To list all available options, run ./bin/uplexad --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/uplexad --log-file uplexad.log --detach

To run as a systemd service, copy uplexad.service to /etc/systemd/system/ and uplexad.conf to /etc/. The example service assumes that the user uplexa 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 uplexa-wallet-cli, and possibly uplexad, if you get crashes refreshing.

Internationalization

See README.i18n.md.

Using Tor

While uPlexa 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 uplexad.conf to disable listening for connections on external interfaces.
• --no-igd on the command line or no-igd=1 in uplexad.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, uplexad uses the default list of servers defined in src/common/dns_utils.cpp.
• TORSOCKS_ALLOW_INBOUND=1 to tell torsocks to allow uplexad 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/uplexad.service for details).
• If you use the wallet with a Tor daemon via the loopback IP (eg, 127.0.0.1:9050), then use --untrusted-daemon unless it is your own hidden service.

Example command line to start uplexad through Tor:

DNS_PUBLIC=tcp torsocks uplexad --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 ./uplexad --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 uPlexa. 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/uplexad `pidof uplexad`

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 uplexad. 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/uplexad /path/to/dumpfile

Print the stack trace with bt

• To run uplexa within gdb:

Type gdb /path/to/uplexad

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

Type run to run uplexad

Analysing memory corruption

There are two tools available:

• ASAN

Configure uPlexa with the -D SANITIZE=ON cmake flag, eg:

cd build/debug && cmake -D SANITIZE=ON -D CMAKE_BUILD_TYPE=Debug ../..

You can then run the uplexa tools normally. Performance will typically halve.

• valgrind

Install valgrind and run as valgrind /path/to/uplexad. It will be very 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 ~/uplexa/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.