From 71a9f8839a1da73c52c30860ec01be503551248f Mon Sep 17 00:00:00 2001
From: Nathan Fisher <nfisher.sr@gmail.com>
Date: Sat, 21 Jan 2023 01:54:52 -0500
Subject: [PATCH] Add `mknod` applet (untested)

---
 Cargo.toml           |   2 +-
 src/cmd/mknod/mod.rs | 124 +++++++++++++++++++++++++++++++++++++++++++
 src/cmd/mod.rs       |   5 +-
 src/mode/parser.rs   |   2 +-
 4 files changed, 130 insertions(+), 3 deletions(-)
 create mode 100644 src/cmd/mknod/mod.rs

diff --git a/Cargo.toml b/Cargo.toml
index 4f592a7..cf91692 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,7 +7,7 @@ edition = "2021"
 
 [dependencies]
 atty = "0.2"
-clap = "4.0"
+clap = "4.1"
 clap_complete = "4.0"
 clap_complete_nushell = "0.1"
 clap_mangen = "0.2"
diff --git a/src/cmd/mknod/mod.rs b/src/cmd/mknod/mod.rs
new file mode 100644
index 0000000..6836ef8
--- /dev/null
+++ b/src/cmd/mknod/mod.rs
@@ -0,0 +1,124 @@
+use super::Cmd;
+use crate::mode::{get_umask, Parser};
+use clap::{value_parser, Arg, ArgAction, ArgMatches, Command};
+use std::{convert::Infallible, error::Error, ffi::CString, io, str::FromStr};
+
+#[derive(Debug, Default)]
+pub struct MkNod;
+
+impl Cmd for MkNod {
+    fn cli(&self) -> clap::Command {
+        Command::new("mknod")
+            .about("make block or character special files")
+            .author("Nathan Fisher")
+            .version(env!("CARGO_PKG_VERSION"))
+            .args([
+                Arg::new("mode")
+                    .short('m')
+                    .long("mode")
+                    .help("set file permission bits to MODE, not a=rw - umask")
+                    .value_name("MODE")
+                    .num_args(1),
+                Arg::new("verbose")
+                    .short('v')
+                    .long("verbose")
+                    .action(ArgAction::SetTrue),
+                Arg::new("file").value_name("NAME").required(true),
+                Arg::new("type")
+                    .value_name("TYPE")
+                    .required(true)
+                    .value_parser(["b", "c", "p"]),
+                Arg::new("major")
+                    .value_name("MAJOR")
+                    .value_parser(value_parser!(u32))
+                    .required_if_eq_any([("type", "b"), ("type", "c")]),
+                Arg::new("minor")
+                    .value_name("MINOR")
+                    .value_parser(value_parser!(u32))
+                    .required_if_eq_any([("type", "b"), ("type", "c")]),
+            ])
+    }
+
+    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 Some(file) = matches.get_one::<String>("file") else {
+            return Err(io::Error::new(io::ErrorKind::Other, "no file given").into());
+        };
+        let Some(t) = matches.get_one::<String>("type") else {
+            return Err(io::Error::new(io::ErrorKind::Other, "no type given").into());
+        };
+        let mut mode = if let Some(m) = matches.get_one::<String>("mode") {
+            Parser::default().parse(m.as_str())?
+        } else {
+            let mask = get_umask();
+            0o666 & !mask
+        };
+        let special: Special = t.parse()?;
+        mode |= special as u32;
+        let dev_t = match special {
+            Special::Block | Special::Char => {
+                let Some(major) = matches.get_one::<u32>("major") else {
+                    return Err(io::Error::new(io::ErrorKind::Other, "missing MAJOR").into());
+                };
+                let Some(minor) = matches.get_one::<u32>("minor") else {
+                    return Err(io::Error::new(io::ErrorKind::Other, "missing MINOR").into());
+                };
+                libc::makedev(*major, *minor)
+            }
+            Special::Pipe => 0,
+        };
+        let fname = CString::new(file.as_str())?;
+        let ret = unsafe { libc::mknod(fname.as_ptr(), mode, dev_t) };
+        if ret != 0 {
+            return Err(io::Error::last_os_error().into());
+        }
+        if matches.get_flag("verbose") {
+            match special {
+                Special::Block => {
+                    println!(
+                        "mknod: created block device with mode {mode:o} major {} and minor {}",
+                        unsafe { libc::major(dev_t) },
+                        unsafe { libc::minor(dev_t) },
+                    );
+                }
+                Special::Char => {
+                    println!(
+                        "mknod: created character device with mode {mode:o} major {} and minor {}",
+                        unsafe { libc::major(dev_t) },
+                        unsafe { libc::minor(dev_t) },
+                    );
+                }
+                Special::Pipe => {
+                    println!("mknod: created fifo with mode {mode:o}");
+                }
+            }
+        }
+        Ok(())
+    }
+
+    fn path(&self) -> Option<crate::Path> {
+        Some(crate::Path::Sbin)
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+enum Special {
+    Block = 0o60000,
+    Char = 0o20000,
+    Pipe = 0o10000,
+}
+
+impl FromStr for Special {
+    type Err = Infallible;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(match s {
+            "b" => Self::Block,
+            "c" => Self::Char,
+            "p" => Self::Pipe,
+            _ => unreachable!(),
+        })
+    }
+}
diff --git a/src/cmd/mod.rs b/src/cmd/mod.rs
index 90b20bd..f25746a 100644
--- a/src/cmd/mod.rs
+++ b/src/cmd/mod.rs
@@ -26,6 +26,7 @@ mod link;
 mod ln;
 mod ls;
 mod mkfifo;
+mod mknod;
 mod mountpoint;
 mod mv;
 mod nologin;
@@ -79,6 +80,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
         "head" => Some(Box::new(head::Head::default())),
         "link" => Some(Box::new(link::Link::default())),
         "mkfifo" => Some(Box::new(mkfifo::MkFifo::default())),
+        "mknod" => Some(Box::new(mknod::MkNod::default())),
         "mountpoint" => Some(Box::new(mountpoint::Mountpoint::default())),
         "nologin" => Some(Box::new(nologin::Nologin::default())),
         "nproc" => Some(Box::new(nproc::Nproc::default())),
@@ -98,7 +100,7 @@ pub fn get(name: &str) -> Option<Box<dyn Cmd>> {
     }
 }
 
-pub static COMMANDS: [&str; 33] = [
+pub static COMMANDS: [&str; 34] = [
     "base32",
     "base64",
     "basename",
@@ -117,6 +119,7 @@ pub static COMMANDS: [&str; 33] = [
     "hostname",
     "link",
     "mkfifo",
+    "mknod",
     "mountpoint",
     "nologin",
     "nproc",
diff --git a/src/mode/parser.rs b/src/mode/parser.rs
index 4008678..6177563 100644
--- a/src/mode/parser.rs
+++ b/src/mode/parser.rs
@@ -101,7 +101,7 @@ pub struct Parser {
 impl Default for Parser {
     fn default() -> Self {
         let umask = get_umask();
-        let mut mode = 0o0777;
+        let mut mode = 0o0666;
         mode &= umask;
         Self {
             mode,