libntirpc-sys 0.2.0

# libntirpc-sys

Low-level bindings for the [libntirpc](https://github.com/nfs-ganesha/ntirpc)
library.

Some documentation for the libary can be found in the Linux man pages
[rpc(3)](https://linux.die.net/man/3/rpc) and
[xdr(3)](https://linux.die.net/man/3/xdr). However, the doc has some
inconsistency with the library, so we should use the doc as a reference not as a
definitive guide.

Its implementation is adapted from the
[libtirpc-sys](https://crates.io/crates/libtirpc-sys) library.

## Dependencies

The build script clones and compiles [libntirpc](https://github.com/nfs-ganesha/ntirpc)
from source, which requires the following tools and libraries:

| Dependency | Package (Ubuntu) | Purpose |
| --- | --- | --- |
| cmake | `cmake` | configure and build libntirpc |
| make | `make` | build libntirpc |
| git | `git` | clone libntirpc (with submodules) |
| clang | `clang` | provide the headers used by bindgen to generate bindings |
| liburcu | `liburcu-dev` | userspace RCU library used by libntirpc |

Install them on Ubuntu with:

```sh
sudo apt install cmake make git clang liburcu-dev
```

## Examples

The [examples](examples/) directory contains a small "hello world" RPC
client-server pair built directly on the raw bindings. They need the
`rpcbind` daemon, which is used to register the server's program number and
for the client to look it up:

```sh
sudo apt install rpcbind
```

Make sure it is running (restart it if the server fails to register):

```sh
sudo systemctl restart rpcbind
```

Run the server in one terminal:

```sh
cargo run --example hello_server
```

It should print `hello server: prog=0x30000001 vers=1 on udp` and register
with rpcbind (check with `rpcinfo -p`). Then, in another terminal, call it:

```sh
cargo run --example hello_client -- Alice 127.0.0.1
```

which prints `Hello, Alice!`. Both arguments are optional (`name` defaults to
`world`, `host` to `127.0.0.1`).