Add `mkfifo` applet

README.md

@@ -34,6 +34,7 @@ code between applets, making for an overall smaller binary.
 - head
 - hostname
 - link
+- mkfifo
 - mountpoint
 - nologin
 - nproc

src/cmd/mkfifo/mod.rs

@@ -0,0 +1,72 @@
+use super::Cmd;
+use crate::mode::Parser;
+use clap::{Arg, ArgAction, ArgMatches, Command};
+use std::{error::Error, ffi::CString, io};
+
+#[derive(Debug, Default)]
+pub struct MkFifo;
+
+impl Cmd for MkFifo {
+    fn cli(&self) -> clap::Command {
+        Command::new("mkfifo")
+            .about("make FIFO special files")
+            .author("Nathan Fisher")
+            .version(env!("CARGO_PKG_VERSION"))
+            .args([
+                Arg::new("mode")
+                    .help(
+                        "Set  the  file  permission  bits of the newly-created \
+                        FIFO to the specified mode value.",
+                    )
+                    .long_help(
+                        "Set  the  file  permission  bits of the newly-created \
+                        FIFO to the specified mode value. The mode option-argument \
+                        shall be the same as the mode operand defined for the \
+                        chmod  utility. In the symbolic_mode strings, the op \
+                        characters '+' and '-' shall be interpreted relative to \
+                        an assumed initial mode of a=rw.",
+                    )
+                    .short('m')
+                    .long("mode")
+                    .value_name("MODE")
+                    .num_args(1),
+                Arg::new("verbose")
+                    .help("print a diagnostic for every pipe created")
+                    .short('v')
+                    .long("verbose")
+                    .action(ArgAction::SetTrue),
+                Arg::new("file").num_args(1..).required(true),
+            ])
+    }
+
+    fn run(&self, matches: Option<&ArgMatches>) -> Result<(), Box<dyn Error>> {
+        let Some(matches) = matches else {
+            return Err(io::Error::new(io::ErrorKind::Other, "no input").into());
+        };
+        let mode = if let Some(m) = matches.get_one::<String>("mode") {
+            Parser::new(0o666).parse(m)?
+        } else {
+            0o666
+        };
+        if let Some(files) = matches.get_many::<String>("file") {
+            for f in files {
+                let fname = CString::new(f.as_str())?;
+                let res = unsafe { libc::mkfifo(fname.as_ptr(), mode) };
+                if res != 0 {
+                    return Err(io::Error::last_os_error().into());
+                }
+                if matches.get_flag("verbose") {
+                    println!(
+                        "{}: created pipe '{f}' with mode {mode:o}",
+                        self.cli().get_name()
+                    );
+                }
+            }
+        }
+        Ok(())
+    }
+
+    fn path(&self) -> Option<crate::Path> {
+        Some(crate::Path::UsrBin)
+    }
+}

src/cmd/mod.rs

@@ -25,6 +25,7 @@ mod hostname;
 mod link;
 mod ln;
 mod ls;
+mod mkfifo;
 mod mountpoint;
 mod mv;
 mod nologin;
@@ -77,6 +78,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
         "groups" => Some(Box::new(groups::Groups::default())),
         "head" => Some(Box::new(head::Head::default())),
         "link" => Some(Box::new(link::Link::default())),
+        "mkfifo" => Some(Box::new(mkfifo::MkFifo::default())),
         "mountpoint" => Some(Box::new(mountpoint::Mountpoint::default())),
         "nologin" => Some(Box::new(nologin::Nologin::default())),
         "nproc" => Some(Box::new(nproc::Nproc::default())),
@@ -96,7 +98,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
     }
 }
 
-pub static COMMANDS: [&str; 32] = [
+pub static COMMANDS: [&str; 33] = [
     "base32",
     "base64",
     "basename",
@@ -114,6 +116,7 @@ pub static COMMANDS: [&str; 32] = [
     "head",
     "hostname",
     "link",
+    "mkfifo",
     "mountpoint",
     "nologin",
     "nproc",