From 79a2ad1d88369a03227295e4a9e81ad035aef07c Mon Sep 17 00:00:00 2001 From: finga Date: Fri, 27 Oct 2023 19:08:26 +0200 Subject: [PATCH] sysvmq: Implement `send` and `recv` and refactor Implement sending to and receiving from SysV IPC message queues. While at it refactor the whole library. Write documentation for the sysvmq library. --- sysvmq/CHANGELOG.md | 29 +++ sysvmq/src/lib.rs | 430 +++++++++++++++++++++++++++++++------------ sysvmq/tests/main.rs | 68 +++++++ 3 files changed, 413 insertions(+), 114 deletions(-) create mode 100644 sysvmq/tests/main.rs diff --git a/sysvmq/CHANGELOG.md b/sysvmq/CHANGELOG.md index 1333e79..477be38 100644 --- a/sysvmq/CHANGELOG.md +++ b/sysvmq/CHANGELOG.md @@ -8,8 +8,37 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). ## [Unreleased] +### Added + +- Basic tests to create, send, receive and delete a message queue as + well as changing the mode of a queue. +- The functions `SysvMq::stat()`, `SysvMq::info()`, + `SysvMq::msg_stat()` and `SysvMq::msg_info()` are added to receive + parameters of a queue. +- The function `new()` passes now a key which is used for the new + message queue. +- A basic test to test the happy path of a queue. +- The function `get()` to gather facts from a message queue. +- The function `set()` to set facts of a message queue. +- The function `create()` to create a message queue. +- The functions `send()` and `SysvMq::send()` to send messages to a + queue. +- The functions `recv()` and `SysvMq::recv()` to receive messages from + a queue. +- The function `SysvMq::delete()` to delete a queue. + ### Changed +- The function `SysvMq::mode()` now also updates the message queue + accordingly. +- Remove `PhantomData` from the `SysvMq` struct. +- The function `SysvMq::create()` is replaced by `SysvMq::new()`. +- Remove generic type for `SysvMq`. +- Rename `unlink_id()` to `delete()`. - Update to the latest verscion of `nix`. - Fix several clippy findings in preperation to enable several lint groups. + +### Removed + +- The function `id_from_key()` was removed. diff --git a/sysvmq/src/lib.rs b/sysvmq/src/lib.rs index 7bd6cfb..1869e56 100644 --- a/sysvmq/src/lib.rs +++ b/sysvmq/src/lib.rs @@ -1,24 +1,216 @@ +#![allow(clippy::doc_markdown)] +//! This library provides a convenient API to SysV IPC message queues. +//! +//! # Example +//! +//! ```rust +//! use sysvmq::{SysvMq, SysvMqError}; +//! +//! fn example() -> Result<(), SysvMqError> { +//! let mut mq = SysvMq::new(0)?; +//! let mut buf = [0u8; 11]; +//! +//! mq.send(b"hello queue")?; +//! mq.recv(&mut buf)?; +//! mq.delete()?; +//! +//! Ok(()) +//! } +//! ``` + use libc::{ - msgctl, msgget, msqid_ds, IPC_CREAT, IPC_INFO, IPC_NOWAIT, IPC_RMID, MSG_INFO,g MSG_STAT, + c_void, msgctl, msgget, msgrcv, msgsnd, msqid_ds, IPC_CREAT, IPC_NOWAIT, IPC_RMID, IPC_SET, }; +pub use libc::{IPC_INFO, IPC_STAT, MSG_INFO, MSG_STAT}; use nix::errno::{errno, Errno}; -use std::{marker::PhantomData, mem::MaybeUninit, ptr}; +use std::{convert::TryFrom, mem::MaybeUninit, ptr}; use thiserror::Error; #[derive(Debug, Error)] +/// An enum containing all errors pub enum SysvMqError { #[error("SysV message queue: {0}")] ErrnoError(&'static str), + #[error("Cannot convert integer")] + From(#[from] std::num::TryFromIntError), } -#[allow(clippy::doc_markdown)] -/// Unlink (delete) an existing SysV IPC message queue. +/// Low level function to create a new SysV IPC message queue. +/// +/// # Example +/// +/// ```rust +/// # use sysvmq::delete; +/// use sysvmq::{create, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_id = create(0, 0o644)?; +/// println!("new queue: {mq_id}"); +/// # delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` /// /// # Errors /// -/// Return an `SysvMqError` when no queue with the given key can be +/// Return `SysvMqError` when the queue cannot be created. +pub fn create(key: i32, mode: i32) -> Result { + let mq = unsafe { msgget(key, IPC_CREAT | mode) }; + + match mq { + -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), + id => Ok(id), + } +} + +/// Low level function to send a message to a SysV IPC message queue. +/// +/// # Example +/// +/// ```rust +/// # use sysvmq::{delete}; +/// use sysvmq::{create, send, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_id = create(0, 0o644)?; +/// let msg = b"hello queue"; +/// send(mq_id, msg, 0)?; +/// # delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` +/// +/// # Errors +/// +/// Return `SysvMqError` when the message cannot be sent to the queue. +pub fn send(id: i32, msg: &[u8], mask: i32) -> Result<(), SysvMqError> { + match unsafe { msgsnd(id, msg.as_ptr().cast::(), msg.len(), mask) } { + -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), + _ => Ok(()), + } +} + +/// Low level function to receive a message from a SysV IPC message +/// queue. +/// +/// # Example +/// +/// ```rust +/// # use sysvmq::{delete, send}; +/// use sysvmq::{create, recv, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_mask = 0o644; +/// let mq_id = create(0, mq_mask)?; +/// let mut buf = [0u8; 32]; +/// # let msg = b"hello queue"; +/// # send(mq_id, msg, 0)?; +/// recv(mq_id, &mut buf, mq_mask)?; +/// println!("received message: {:?}", buf); +/// # delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` +/// +/// # Errors +/// +/// Return `SysvMqError` when the message cannot be received from the +/// queue. +pub fn recv(id: i32, msg: &mut [u8], mask: i32) -> Result<(), SysvMqError> { + match unsafe { msgrcv(id, msg.as_mut_ptr().cast::(), msg.len(), 0, mask) } { + -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), + _ => Ok(()), + } +} + +/// Low level function to get parameters of a SysV IPC message queue. +/// +/// # Example +/// +/// ```rust +/// # use sysvmq::{delete}; +/// use sysvmq::{create, get, IPC_STAT, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_id = create(0, 0o644)?; +/// let mq_stat = get(mq_id, IPC_STAT)?; +/// println!("received message: {:?}", mq_stat); +/// # delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` +/// +/// # Errors +/// +/// Return `SysvMqError` when the parameters cannot be gathered. +pub fn get(id: i32, cmd: i32) -> Result { + let mut ipc_info = MaybeUninit::::uninit(); + let ret; + + let ipc_info = unsafe { + ret = msgctl(id, cmd, ipc_info.as_mut_ptr()); + ipc_info.assume_init() + }; + + match ret { + 0 => Ok(ipc_info), + _ => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), + } +} + +/// Low level function to set parameters of a SysV IPC message queue. +/// +/// # Example +/// +/// ```rust +/// # use sysvmq::{delete}; +/// use sysvmq::{create, get, IPC_STAT, set, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_id = create(0, 0o644)?; +/// let mut mq_stat = get(mq_id, IPC_STAT)?; +/// mq_stat.msg_perm.mode = 0o666; +/// set(mq_id, &mut mq_stat)?; +/// # delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` +/// +/// # Errors +/// +/// Return `SysvMqError` when the parameters cannot be set. +pub fn set(id: i32, data: &mut msqid_ds) -> Result<(), SysvMqError> { + match unsafe { msgctl(id, IPC_SET, data) } { + 0 => Ok(()), + _ => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), + } +} + +/// Low level function to delete a SysV IPC message queue. +/// +/// # Example +/// +/// ```rust +/// use sysvmq::{create, delete, SysvMqError}; +/// +/// fn main() -> Result<(), SysvMqError> { +/// let mq_id = create(0, 0o644)?; +/// delete(mq_id)?; +/// +/// Ok(()) +/// } +/// ``` +/// +/// # Errors +/// +/// Return `SysvMqError` when no queue with the given key can be /// found. -pub fn unlink_id(id: i32) -> Result<(), SysvMqError> { +pub fn delete(id: i32) -> Result<(), SysvMqError> { let res = unsafe { msgctl(id, IPC_RMID, ptr::null::().cast_mut()) }; match res { @@ -27,127 +219,137 @@ pub fn unlink_id(id: i32) -> Result<(), SysvMqError> { } } -#[allow(clippy::doc_markdown)] -/// Get the id of an existing SysV IPC message queue by passing its -/// key. -/// -/// # Errors -/// -/// Return an `SysvMqError` when no queue with the given key can be -/// found. -pub fn id_from_key(key: i32) -> Result { - let id = unsafe { msgget(key, 0) }; +#[derive(Clone, Debug)] +/// Struct representation of a Message Queue +pub struct SysvMq { + pub key: i32, + pub id: i32, + pub mask: i32, + pub mode: i32, +} - match id { - -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), - id => Ok(id), +impl Default for SysvMq { + fn default() -> Self { + Self { + key: 0, + id: -1, + mask: 0, + mode: 0o644, + } } } -#[allow(clippy::doc_markdown)] -/// Get the info about an existing SysV IPC message queue. -pub fn ipc_info(id: i32) { - let mut ipc_info = MaybeUninit::::uninit(); - - let ipc_info = unsafe { - msgctl(id, IPC_INFO, ipc_info.as_mut_ptr()); - ipc_info.assume_init() - }; - - println!("info: {ipc_info:?}"); -} - -#[allow(clippy::doc_markdown)] -/// Get the stats about an existing SysV IPC message queue. -pub fn stat_info(id: i32) { - let mut stat_info = MaybeUninit::::uninit(); - - let stat_info = unsafe { - msgctl(id, MSG_STAT, stat_info.as_mut_ptr()); - stat_info.assume_init() - }; - - println!("info: {stat_info:?}"); -} - -#[allow(clippy::doc_markdown)] -/// Get the message info about an existing SysV IPC message queue. -pub fn msg_info(id: i32) { - let mut msg_info = MaybeUninit::::uninit(); - - let msg_info = unsafe { - msgctl(id, MSG_INFO, msg_info.as_mut_ptr()); - msg_info.assume_init() - }; - - println!("info: {msg_info:?}"); -} - -pub struct SysvMq { - pub id: i32, - pub key: i32, - message_mask: i32, - mode: i32, - types: PhantomData, -} - -impl SysvMq { - /// Create a new message queye with the given key. +impl SysvMq { + /// Create a new message SysV IPC message queue with the given + /// key. /// /// # Errors /// - /// Return an `SysvMqError` when no queue with the given key can be - /// created. - pub fn create(&mut self, key: i32) -> Result<&Self, SysvMqError> { - self.key = key; - self.id = unsafe { msgget(self.key, IPC_CREAT | self.mode) }; - - match self.id { - -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), - _ => Ok(self), - } + /// Return `SysvMqError` when the queue cannot be created. + pub fn new(key: i32) -> Result { + let mut mq = Self::default(); + mq.key = key; + mq.id = create(mq.key, mq.mode)?; + Ok(mq) } - /// Open an existing message queye with the given key. + /// Open an existing SysV IPC message queye with the given key. + /// + /// # Errors + /// + /// Return `SysvMqError` when the queue cannot be opened. + pub fn open(key: i32, id: i32) -> Result { + let mut mq = Self::default(); + mq.key = key; + mq.id = id; + mq.mode = i32::from(get(mq.id, IPC_STAT)?.msg_perm.mode); + Ok(mq) + } + + /// Set the mode of a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the mode of the queue cannot be set. + pub fn mode(&mut self, mode: i32) -> Result<(), SysvMqError> { + self.mode = mode; + let mut stats = get(self.id, IPC_STAT)?; + stats.msg_perm.mode = u16::try_from(self.mode)?; + set(self.id, &mut stats) + } + + /// Set the mask of a SysV IPC message queue to nonblocking + /// (`IPC_NOWAIT`). + pub fn nonblocking(&mut self) { + self.mask |= IPC_NOWAIT; + } + + /// Send a message to a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the message cannot be sent to the queue. + pub fn send(&mut self, msg: &[u8]) -> Result<(), SysvMqError> { + send(self.id, msg, self.mask) + } + + /// Receive a message from a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the message cannot be received from the + /// queue. + pub fn recv(&mut self, msg: &mut [u8]) -> Result<(), SysvMqError> { + recv(self.id, msg, self.mask) + } + + /// Receive stats from a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the stats cannot be gathered from + /// the queue. + pub fn stat(&self) -> Result { + get(self.id, IPC_STAT) + } + + /// Receive info from a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the info cannot be gathered from the + /// queue. + pub fn info(&self) -> Result { + get(self.id, IPC_INFO) + } + + /// Receive message stats from a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the message stats cannot be gathered + /// from the queue. + pub fn msg_stat(&self) -> Result { + get(self.id, MSG_STAT) + } + + /// Receive message info from a SysV IPC message queue. + /// + /// # Errors + /// + /// Return `SysvMqError` when the message info cannot be gathered + /// from the queue. + pub fn msg_info(&self) -> Result { + get(self.id, MSG_INFO) + } + + /// Delete an existing SysV IPC message queue. /// /// # Errors /// /// Return an `SysvMqError` when no queue with the given key can be /// found. - pub fn open(mut self, key: i32) -> Result { - self.key = key; - self.id = unsafe { msgget(self.key, self.mode) }; - - match self.id { - -1 => Err(SysvMqError::ErrnoError(Errno::from_i32(errno()).desc())), - _ => Ok(self), - } - } - - pub fn mode(&mut self, mode: i32) -> &Self { - self.mode = mode; - self - } - - pub fn nonblocking(&mut self) -> &Self { - self.message_mask |= IPC_NOWAIT; - self - } - - #[must_use] - pub const fn new() -> Self { - Self { - id: -1, - key: 0, - message_mask: 0, - mode: 0o644, - types: PhantomData, - } - } -} - -impl Default for SysvMq { - fn default() -> Self { - Self::new() + pub fn delete(&mut self) -> Result<(), SysvMqError> { + delete(self.id) } } diff --git a/sysvmq/tests/main.rs b/sysvmq/tests/main.rs new file mode 100644 index 0000000..8c08550 --- /dev/null +++ b/sysvmq/tests/main.rs @@ -0,0 +1,68 @@ +use sysvmq::SysvMq; + +#[test] +fn new_send_recv_delete() { + let mut mq = SysvMq::new(0).expect("could not create SysV message queue with key 0"); + let msg = b"this is a test"; + let mut buf = [0u8; 14]; + mq.send(msg) + .expect("could not send message to SysV message queue"); + mq.recv(&mut buf) + .expect("could not receive message from SysV message queue"); + mq.delete().expect("could not destroy SysV message queue"); + assert_eq!(msg, &buf); +} + +#[test] +fn separate_send_recv_clone() { + let mut sender = SysvMq::new(0).expect("could not create SysV message queue with key 0"); + let mut receiver = sender.clone(); + let msg = b"this is another test"; + let mut buf = [0u8; 20]; + sender + .send(msg) + .expect("could not send message to SysV message queue"); + receiver + .recv(&mut buf) + .expect("could not receive message from SysV message queue"); + sender + .delete() + .expect("could not destroy SysV message queue"); + assert_eq!(msg, &buf); +} + +#[test] +fn separate_send_recv_open() { + let mut sender = SysvMq::new(0).expect("could not create SysV message queue with key 0"); + let mut receiver = SysvMq::open(sender.key, sender.id) + .expect("could not create second handle to SysV message queue"); + let msg = b"this is another test"; + let mut buf = [0u8; 20]; + sender + .send(msg) + .expect("could not send message to SysV message queue"); + receiver + .recv(&mut buf) + .expect("could not receive message from SysV message queue"); + sender + .delete() + .expect("could not destroy SysV message queue"); + assert_eq!(msg, &buf); +} + +#[test] +fn change_mode() { + let mut mq = SysvMq::new(0).expect("could not create SysV message queue with key 0"); + let init_stats = mq + .stat() + .expect("could not get stats from SysV message queue"); + mq.mode(0o666) + .expect("could not set mode of SysV message queue"); + let new_stats = mq + .stat() + .expect("could not get stats from SysV message queue"); + mq.delete().expect("could not destroy SysV message queue"); + + assert_eq!(0o644, init_stats.msg_perm.mode); + assert_eq!(0o666, new_stats.msg_perm.mode); +}