retval(1) sans documentation

Makefile

@@ -32,7 +32,7 @@ RUSTLIBS = --extern getopt=build/o/libgetopt.rlib \
 CFLAGS += -I$(SYSEXITS)
 
 .PHONY: all
-all: dj false fop hru intcmp mm npc rpn scrut str strcmp swab true
+all: dj false fop hru intcmp mm npc retval rpn scrut str strcmp swab true
 
 # keep build/include until bindgen(1) has stdin support
 # https://github.com/rust-lang/rust-bindgen/issues/2703
@@ -122,6 +122,11 @@ npc: build/bin/npc
 build/bin/npc: src/npc.c build
 	$(CC) $(CFLAGAS) -o $@ src/npc.c
 
+.PHONY: retval
+retval: build/bin/retval
+build/bin/retval: src/retval.rs build rustlibs
+	$(RUSTC) $(RUSTFLAGS) $(RUSTLIBS) -o $@ src/retval.rs
+
 .PHONY: rpn
 rpn: build/bin/rpn
 build/bin/rpn: src/rpn.rs build rustlibs

docs/simexec.1

@@ -1,49 +0,0 @@
-.TH SIMEXEC 1
-
-.SH NAME
-
-simexec \(en execute a program with the given argv
-
-.SH SYNOPSIS
-
-simexec
-.RB [ pathname ]
-.RB [ argv... ]
-
-.SH DESCRIPTION
-
-Simexec executes a given program with the given argv.
-
-.SH PITFALLS
-
-Non-binary programs cannot be executed. The PATH environment variable is not used and a valid pathname (relative or absolute) must be specified.
-.PP
-Simexec relies on the user to take proper precautions.
-argv is not just the operands for the program but in fact directly the argv it will receive in runtime;
-the first argv entry is the program's name, and forgoing this, though acceptable by simexec, can break customary assumptions.
-for example, the true(1) implementation in the GNU coreutils suffers a segmentation fault if there is no argv[0].
-.PP
-While POSIX.1-2017 doesn't mandate there being an argv[0] per se a Strictly Conforming POSIX Application must pass an argv[0].
-It has also been said that those who do not pass an argv[0] are mean and nasty and smell of elderberries.
-.PP
-Simexec directly uses the execv library function. It cannot execute shell scripts intelligently (via shebang).
-It is inadviseable to use simexec as an alternative to simply calling a program, and in fact probably inadviseable to use simexec at all.
-
-.SH DIAGNOSTICS
-
-Simexec returns the value of execv(3), which will be -1 (or 0xFF; 255) if an error occurs.
-This is not distinguishable from the executed program returning the same exit status.
-.PP
-Simexec will print a error message and return the proper sysexits(3) value if used in an invalid manner.
-
-.SH COPYRIGHT
-
-Public domain.
-
-.SH SEE ALSO
-
-exec(3)
-.PP
-The C89 standard's draft, section 2.1.2.2: "Hosted environment".
-.PP
-POSIX.1-2017 System Interfaces: execv. Particularly under the RATIONALE section header.

src/retval.rs

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2023 DTB <trinity@trinity.moe>
+ * Copyright (c) 2024 DTB <trinity@trinity.moe>
  * SPDX-License-Identifier: AGPL-3.0-or-later
  *
  * This program is free software: you can redistribute it and/or modify it under
@@ -16,20 +16,24 @@
  * along with this program. If not, see https://www.gnu.org/licenses/.
  */
 
-#include <stdio.h> /* fprintf(3), NULL */
+use std::{ env::args, process::ExitCode };
-#include <unistd.h> /* execv(3), */
-#include <sysexits.h> /* EX_USAGE */
 
-char *program_name = "simexec";
+extern crate sysexits;
+use sysexits::EX_USAGE;
 
-int main(int argc, char *argv[]){
+fn usage(s: &str) -> ExitCode {
-
+	eprintln!("Usage: {} status", s);
-	if(argc < 2){
+	ExitCode::from(EX_USAGE)
-		fprintf(stderr, "Usage: %s binary argv...\n",
+}
-			argv[0] == NULL ? program_name : argv[0]
+
-		);
+fn main() -> ExitCode {
-		return EX_USAGE;
+	let argv = args().collect::<Vec<String>>();
-	}
+
-
+	match argv.len() {
-	execv(argv[1], &argv[2]);
+		2 => match argv[1].parse::<u8>() {
+				Ok(e) => ExitCode::from(e),
+				_ => usage(&argv[0])
+			},
+		_ => usage(&argv[0])
+	}
 }