Add new subcommand list

Also add it to the readme and manpage.

README.md

@@ -46,10 +46,10 @@ from `target/{debug,release}/mqrs` depending on which
 one you built.
 
 ## Using `mqrs`
-`mqrs` supports five commands: `create`, `info`, `unlink`, `send` and
-`recv`. All commands do not have to be specified fully. If the
-command is clearly distinguishable from all the others, it does not
-have to be completed further.
+`mqrs` supports five commands: `create`, `info`, `list`, `unlink`,
+`send` and `recv`. All commands do not have to be specified fully. If
+the command is clearly distinguishable from all the others, it does
+not have to be completed further.
 
 ### Create a message queue
 Use the `create` command to create a new POSIX message queue. Following
@@ -62,6 +62,11 @@ optional arguments are supported:
 Use the `info` command to print further information about a message
 queue.
 
+### List all message queues
+Use the `list` command to print a list of all message
+queues. Following option argument is supported:
+- `-a`, `--all`: Print all available information
+
 ### Delete a message queue
 Use the `unlink` command to delete a message queue.
 

mqrs.1

@@ -11,6 +11,8 @@ is a small cli program to handle POSIX message queues. Supported commands are
 ,
 .B info\
 ,
+.B list\
+,
 .B unlink\
 ,
 .B send
@@ -18,8 +20,8 @@ and
 .B recv
 .
 All commands do not have to be specified fully. If the command is
-clearly distinguishable from all the others, it does not have to be
-completed further.
+clearly distinguishable from all the others, it is not needed to
+complete it further.
 .SH OPTIONS
 .TP 8
 .B \-h, \-\-help
@@ -90,6 +92,21 @@ Prints help information
 .B \-v, \-\-verbose
 Produce verbose output
 .RE
+.SS list [FLAGS]
+Print a list of all existing POSIX message queues.
+.TP 8
+.SS FLAGS
+.RS
+.TP 8
+.B \-h, \-\-help
+Prints help information
+.TP 8
+.B \-v, \-\-verbose
+Produce verbose output
+.TP 8
+.B \-a, \-\-all
+Print all available information
+.RE
 .SS recv [FLAGS] [OPTIONS] \fI<QUEUE>\fP
 Receive and print one or more messages message from a message queue.
 .TP 8

src/main.rs

@@ -7,6 +7,7 @@ mod posix;
 enum Command {
     Create(posix::Create),
     Info(posix::Info),
+    List(posix::List),
     Unlink(posix::Unlink),
     Send(posix::Send),
     Recv(posix::Recv),
@@ -47,6 +48,7 @@ fn main() -> Result<()> {
         Command::Unlink(u) => u.run()?,
         Command::Send(s) => s.run()?,
         Command::Recv(r) => r.run()?,
+        Command::List(l) => l.run()?,
     }
 
     Ok(())

src/posix.rs

@@ -1,11 +1,13 @@
 mod create;
 mod info;
+mod list;
 mod recv;
 mod send;
 mod unlink;
 
 pub use create::Create;
 pub use info::Info;
+pub use list::List;
 pub use recv::Recv;
 pub use send::Send;
 pub use unlink::Unlink;

src/posix/list.rs

@@ -0,0 +1,58 @@
+use anyhow::{anyhow, Result};
+use chrono::{DateTime, Local};
+use clap::Clap;
+use log::warn;
+use std::{fs, os::unix::fs::PermissionsExt};
+
+/// Print information about an existing message queue
+#[derive(Clap, Debug)]
+pub struct List {
+    /// Show all parameters
+    #[clap(short, long)]
+    all: bool,
+}
+
+impl List {
+    pub fn run(&self) -> Result<()> {
+        match self.all {
+            false => println!("Name"),
+            true => println!(
+                "{0: <10} {1: <10} {2: <12} {3: <26}  {4: <26}",
+                "Name", "Size", "Permissions", "Modified", "Accessed",
+            ),
+        }
+
+        for mq in fs::read_dir("/dev/mqueue")? {
+            match mq {
+                Ok(mq) => {
+                    print!(
+                        "/{0: <10}",
+                        mq.file_name().into_string().map_err(|e| anyhow!(
+                            "Could not convert queue name to string: {:?}",
+                            e
+                        ))?
+                    );
+
+                    if self.all {
+                        let metadata = mq.metadata()?;
+                        let modified: DateTime<Local> = metadata.modified()?.into();
+                        let accessed: DateTime<Local> = metadata.accessed()?.into();
+
+                        print!(
+                            "{0: <10} {1: <12o} {2: <26}  {3: <26}",
+                            metadata.len(),
+                            metadata.permissions().mode(),
+                            modified,
+                            accessed,
+                        );
+                    }
+
+                    println!();
+                }
+                Err(e) => warn!("Could not read file: {:?}", e),
+            }
+        }
+
+        Ok(())
+    }
+}