wownero/README.md

# ~~Mo~~Wownero

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

## Resources

- Web: [wownero.org](http://wownero.org)
- Twitter: [@w0wn3r0](https://twitter.com/w0wn3r0)
- Discord: [discord.gg/sQt74ep](https://discord.gg/sQt74ep)
- Reddit: [/r/wownero](https://www.reddit.com/r/wownero)
- Mail: [wownero@protonmail.com](mailto:wownero@protonmail.com)
- GitHub: [https://github.com/wownero/wownero](https://github.com/wownero/wownero)
- IRC: [#wownero on Freenode](https://kiwiirc.com/client/irc.freenode.net/?nick=suchchatter|?#wownero)
- Bitmessage Chan: wownero (`BM-2cSzWtrj2pzLva9GF1Jp2TYsnLjrnJpvba`)

## Vulnerability response

- TODO


## Announcements

You can subscribe to an [announcement listserv](https://lists.getmonero.org) 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    | TODO
| Ubuntu 16.04          |  amd64   | TODO
| Ubuntu 16.04          |  armv7   | TODO
| Debian Stable         |  armv8   | TODO
| OSX 10.10             |  amd64   | TODO
| OSX 10.11             |  amd64   | TODO
| OSX 10.12             |  amd64   | TODO
| FreeBSD 11            |  amd64   | TODO
| DragonFly BSD 4.6     |  amd64   | TODO
| Windows (MSYS2/MinGW) |  i686    | TODO
| Windows (MSYS2/MinGW) |  amd64   | TODO

## Coverage

| Type      | Status |
|-----------|--------|
| License   | [![License](https://img.shields.io/badge/license-BSD3-blue.svg)](https://opensource.org/licenses/BSD-3-Clause)

## Introduction

Wownero is a fork of the private cryptocurrenty Monero with two major changes: A capped emmision that disallows infinite coin creation 10x the coin for 10x the W0W; Wownero is a fairly launched coin with no premine. It's not a fork of another blockchain. With its own genesis block there is no degradation of privacy due to ring signatures using different participants for the same tx outputs on opposing forks.

**Privacy:** Wownero 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, Wownero 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 Wownero. 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 Wownero 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 Wownero'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. All pull requests will be considered safe until the US dollar valuation of 1 Wownero equals $1000. After this valuation has been reached, more reseach will be needed to introduce experimental cryptography and/or code into the codebase.  

## Supporting the project

Wownero is a 100% community-sponsored endeavor. If you want to join our efforts, the easiest thing you can do is support the project financially.

The Wownero donation address (mostly reserved for hookers and blow) is: `Wo3MWeKwtA918DU4c69hVSNgejdWFCRCuWjShRY66mJkU2Hv58eygJWDJS1MNa2Ge5M1WjUkGHuLqHkweDxwZZU42d16v94mP`

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

The Monero Bitcoin donation address is: `1KTexdemPdxSBcG55heUuTjDRYqbC5ZL8H`

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

<img width="100" src="https://botw-pd.s3.amazonaws.com/styles/logo-thumbnail/s3/0024/1083/brand.gif"/><img width="100" src="https://blogvecindad.com/imagenes/2007/02/brawndo.jpg"/><img width="100" src="https://www.subscribepro.com/wp-content/uploads/2016/04/logo-depend-250x130.png"/>

## License

See [LICENSE](LICENSE).

## Contributing

If you want to help out, see [CONTRIBUTING](CONTRIBUTING.md) for a set of guidelines.

## Scheduled software upgrades

Wownero uses a fixed-schedule mandatory software upgrade (hard fork) mechanism to implement new features. This means that users of Wownero (end users and service providers) need to run current versions and upgrade their software on a regular schedule.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 Wownero 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 Wownero version | Recommended Wownero version | Details                                                                            |  
| ------------------------------ | -----------| ----------------- | ---------------------- | -------------------------- | ---------------------------------------------------------------------------------- |
| 1                              | 2018-04-01 | v7                | v0.1.0.0               | v0.1.0.0                  | Cryptonight variant 1, ringsize >= 8, sorted inputs
| 6969                           | 2018-04-24 | v8                | v0.2.0.0               | v0.2.0.0                  | Bulletproofs, LWMA difficulty algorithm, ringsize >= 10, reduce unlock to 4
| 53666                          | 2018-10-06 | v9                | v0.3.0.0               | v0.3.0.0                  | Cryptonight variant 2, LWMA v2, ringsize = 22, XXX

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 mandatory 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 Wownero 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  |
| pcsclite     | ?             | NO       | `libpcsclite-dev`  | ?            | `pcsc-lite pcsc-lite-devel` | NO | Ledger     |          


[^] 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 libpcsclite-dev libpgm-dev```

### Cloning the repository

`$ git clone https://github.com/wownero/wownero`

Submodules are fetched and updated automatically. If you wish to
do this manually, run CMake flag `-DMANUAL_SUBMODULES=ON` to opt out.

### Build instructions

Wownero uses the CMake build system and a top-level [Makefile](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 wownero
        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/wownero/build/release/bin"` to `.profile`

* Run Wownero with `wownerod --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 Windows:

Binaries for Windows are built on Windows using the MinGW toolchain within
[MSYS2 environment](http://msys2.github.io). 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](http://msys2.github.io), 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 wownero 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`.

### 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 Wownero.

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 wownero: `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.

### 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 wownerod

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/wownerod

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

To run as a systemd service, copy
[wownerod.service](utils/systemd/wownerod.service) to `/etc/systemd/system/` and
[wownerod.conf](utils/conf/wownerod.conf) to `/etc/`. The [example
service](utils/systemd/wownerod.service) assumes that the user `wownero` exists
and its home is the data directory specified in the [example
config](utils/conf/wownerod.conf).

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

## Internationalization

See [README.i18n.md](README.i18n.md).

## Using Tor

While Wownero 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
  wownerod.conf to disable listening for connections on external interfaces.
* `--no-igd` on the command line or `no-igd=1` in wownerod.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, wownerod uses the default list of
  servers defined in [src/common/dns_utils.cpp](src/common/dns_utils.cpp).
* `TORSOCKS_ALLOW_INBOUND=1` to tell torsocks to allow wownerod 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/wownerod.service](utils/systemd/wownerod.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 wownerod through Tor:

    DNS_PUBLIC=tcp torsocks wownerod --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 34568 -j ACCEPT
    DNS_PUBLIC=tcp torsocks ./wownerod --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 Wownero. 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/wownerod `pidof wownerod` 
```

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 wownerod. 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/wownerod /path/to/dumpfile`

Print the stack trace with `bt`

* To run wownero within gdb:

Type `gdb /path/to/wownerod`

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

Type `run` to run wownerod

### Analysing memory corruption

We use the tool `valgrind` for this.

Run with `valgrind /path/to/wownerod`. 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 ~/wownero/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.