- Check out our [Vulnerability Response Process](https://loki-project.github.io/loki-docs/Contributing/VULNERABILITY_RESPONSE_LOKI), encourages prompt disclosure of any Vulnerabilities
Loki is a private cryptocurrency based on Monero. Loki currently offers an incentivised full node layer, over the coming months we will be looking to support a secondary p2p network (Lokinet) and a messenger that offers private communications based on the Signal protocol (Loki Messenger).
More information on the project can be found on the website and in the whitepaper.
Loki is an open source project, and we encourage contributions from anyone with something to offer. For more information on contributing, please contact team@loki.network
## Compiling Loki 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
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/ ```
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.
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](#note-for-raspbian-jessie-users).
* If using an external hard disk without an external power supply, ensure it gets enough power to avoid hardware issues when syncing, by adding the line "max_usb_current=1" to /boot/config.txt
* The resulting executables can be found in `build/release/bin`
* Add `PATH="$PATH:$HOME/loki/build/release/bin"` to `.profile`
* Run Loki with `lokid --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 Loki is a bit more complicated. The version of Boost available in the Debian Jessie repositories is too old to use with Loki, 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
* Then, install the dependencies for Loki 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):
* Download and install the [MSYS2 installer](https://www.msys2.org), either the 64-bit (x86_64) or the 32-bit (i686) package, depending on your system.
* Note: Installation must be on the C drive and root directory as result of [Monero issue 3167](https://github.com/monero-project/monero/issues/3167).
* Open the MSYS shell via the `MSYS2 MSYS` shortcut in the Start Menu or "C:\msys64\msys2_shell.cmd -msys"
* Exit the MSYS shell using Alt+F4 when you get a warning stating: "terminate MSYS2 without returning to shell and check for updates again/for example close your terminal window instead of calling exit"
* Open the MSYS MinGW shell via the `MSYS2 MinGW 64-bit` shortcut or "C:\msys64\msys2_shell.cmd -mingw64" for 64-bit builds or via the `MSYS2 MinGW 32-bit` shortcut or "C:\msys64\msys2_shell.cmd -mingw32" for 32-bit builds
* **Optional**: if you would like a specific [version/tag](https://github.com/loki-project/loki/tags), do a git checkout for that version. eg. 'v3.0.4'. If you don't care about the version and just want binaries from master, skip this step:
The project can be built from scratch by following instructions for Linux above(but use `gmake` instead of `make`). If you are running loki 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`.
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"):
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
Using `depends` might also be easier to compile Loki on Windows than using MSYS. Activate Windows Subsystem for Linux (WSL) with a distro (for example Ubuntu), install the apt build-essentials and follow the `depends` steps as depicted above.
The produced binaries still link libc dynamically. If the binary is compiled on a current distribution, it might not run on an older distribution with an older installation of libc. Passing `-DBACKCOMPAT=ON` to cmake will make sure that the binary will run on systems having at least libc version 2.17.
This section contains general instructions for debugging failed installs or problems encountered with Loki. 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:
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 lokid. 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/lokid /path/to/dumpfile`
Print the stack trace with `bt`
* To run loki within gdb:
Type `gdb /path/to/lokid`
Pass command-line options with `--args` followed by the relevant arguments
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 ~/loki/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.
