mm(1): adds ioerr(), usage(), and oser() functions

src/mm.rs

@@ -20,9 +20,9 @@
 use std::{
 	env::args,
 	fs::File,
-	io::{ stdin, stdout, stderr, BufWriter, Read, Write },
+	io::{ Error, BufWriter, Read, Write, stderr, stdin, stdout },
 	os::fd::{ AsRawFd, FromRawFd },
-	process::{ exit, ExitCode },
+	process::{ ExitCode, exit},
 };
 
 extern crate getopt;
@@ -47,15 +47,29 @@ use ArgMode::*;
 
 enum ArgMode { In, Out }
 
+fn ioerr(argv0: &String, e: Error) -> ExitCode {
+	eprintln!("{}: {}", argv0, e.strerror());
+	ExitCode::from(EX_IOERR as u8)
+}
+
+#[cfg(target_os="openbsd")]
+fn oserr(argv0: &String, e: Error) -> ExitCode {
+	eprintln!("{}: {}", argv0, e.strerror());
+	ExitCode::from(EX_OSERR as u8)
+}
+
+fn usage(argv0: &String) -> ExitCode {
+	eprintln!("Usage: {} [-aetu] [-i input] [-o output]", argv0);
+	ExitCode::from(EX_USAGE as u8)
+}
+
 fn main() -> ExitCode {
 	let argv = args().collect::<Vec<_>>();
-	let usage = format!("Usage: {} [-aetu] [-i input] [-o output]", argv[0]);
 
 	#[cfg(target_os="openbsd")] {
 		let promises = Promises::new("cpath rpath stdio unveil wpath");
 		if let Err(e) = pledge(Some(promises), None) {
-			eprintln!("{}: {}", argv[0], e.strerror());
+			return oserr(&argv[0], e);
-			return ExitCode::from(EX_OSERR as u8);
 		}
 	}
 
@@ -85,8 +99,7 @@ fn main() -> ExitCode {
 				mode = Some(Out); /* latest argument == -o */
 			},
 			Err(_) | Ok(_) => {
-				eprintln!("{}", usage);
+				return usage(&argv[0]);
-				return ExitCode::from(EX_USAGE as u8);
 			},
 		};
 
@@ -111,8 +124,7 @@ fn main() -> ExitCode {
 			let perms = UnveilPerms::new(vec!['r']);
 
 			if let Err(e) = unveil(Some(&input), Some(perms)) {
-				eprintln!("{}: {}", argv[0], e.strerror());
+				return oserr(&argv[0], e);
-				return ExitCode::from(EX_OSERR as u8);
 			}
 		}
 
@@ -120,20 +132,17 @@ fn main() -> ExitCode {
 			let perms = UnveilPerms::new(vec!['c', 'w']);
 
 			if let Err(e) = unveil(Some(&output), Some(perms)) {
-				eprintln!("{}: {}", argv[0], e.strerror());
+				return oserr(&argv[0], e);
-				return ExitCode::from(EX_OSERR as u8);
 			}
 		}
 
 		if let Err(e) = unveil(None, None) {
-			eprintln!("{}: {}", argv[0], e.strerror());
+			return oserr(&argv[0], e);
-			return ExitCode::from(EX_OSERR as u8);
 		}
 	}
 
 	if ins.is_empty() && outs.is_empty() && argv.len() > optind {
-		eprintln!("Usage: {}", usage);
+		return usage(&argv[0]);
-		return ExitCode::from(EX_USAGE as u8);
 	}
 
 	/* use stdin if no inputs are specified */
@@ -153,7 +162,7 @@ fn main() -> ExitCode {
 		match File::open(file) {
 			Ok(f) => f,
 			Err(e) => {
-				eprintln!("{}: {}: {}", argv[0], file, e.strerror());
+				let _ = ioerr(&argv[0], e);
 				exit(EX_IOERR);
 			},
 		}
@@ -180,7 +189,7 @@ fn main() -> ExitCode {
 		match options {
 			Ok(f) => return f,
 			Err(e) => {
-				eprintln!("{}: {}: {}", argv[0], file, e.strerror());
+				let _ = ioerr(&argv[0], e);
 				exit(EX_IOERR);
 			},
 		};
@@ -205,21 +214,19 @@ fn main() -> ExitCode {
 	for file in inputs {
 		for byte in file.bytes().map(|b| {
 			b.unwrap_or_else(|e| {
-				eprintln!("{}: {}", argv[0], e.strerror());
+				let _ = ioerr(&argv[0], e);
 				exit(EX_IOERR);
 			})
 		}) {
 			for out in &mut outputs {
 				if let Err(e) = out.write(&[byte]) {
-					eprintln!("{}: {}", argv[0], e.strerror());
+					return ioerr(&argv[0], e);
-					return ExitCode::from(EX_IOERR as u8);
 				}
 
 				if u {
 					/* immediately flush the output for -u */
 					if let Err(e) = out.flush() { 
-						eprintln!("{}: {}", argv[0], e.strerror());
+						return ioerr(&argv[0], e);
-						return ExitCode::from(EX_IOERR as u8);
 					}
 				}
 			}