From c8aa5a6b578c1149431661236724fb1c1d7b94ef Mon Sep 17 00:00:00 2001
From: Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
Date: Sat, 1 Mar 2025 22:38:19 +0200
Subject: [PATCH] mesg: Add tool
---
Cargo.lock | 10 ++++
Cargo.toml | 2 +
src/uu/mesg/Cargo.toml | 16 ++++++
src/uu/mesg/mesg.md | 7 +++
src/uu/mesg/src/main.rs | 1 +
src/uu/mesg/src/mesg.rs | 101 +++++++++++++++++++++++++++++++++++++
tests/by-util/test_mesg.rs | 36 +++++++++++++
tests/tests.rs | 4 ++
8 files changed, 177 insertions(+)
create mode 100644 src/uu/mesg/Cargo.toml
create mode 100644 src/uu/mesg/mesg.md
create mode 100644 src/uu/mesg/src/main.rs
create mode 100644 src/uu/mesg/src/mesg.rs
create mode 100644 tests/by-util/test_mesg.rs
diff --git a/Cargo.lock b/Cargo.lock
index 8ff316a..e447cdc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -976,6 +976,7 @@ dependencies = [
"uu_lscpu",
"uu_lslocks",
"uu_lsmem",
+ "uu_mesg",
"uu_mountpoint",
"uu_rev",
"uu_setsid",
@@ -1067,6 +1068,15 @@ dependencies = [
"uucore",
]
+[[package]]
+name = "uu_mesg"
+version = "0.0.1"
+dependencies = [
+ "clap",
+ "nix",
+ "uucore",
+]
+
[[package]]
name = "uu_mountpoint"
version = "0.0.1"
diff --git a/Cargo.toml b/Cargo.toml
index 2c7adc1..e4242c5 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,6 +34,7 @@ feat_common_core = [
"lscpu",
"lslocks",
"lsmem",
+ "mesg",
"mountpoint",
"rev",
"setsid",
@@ -79,6 +80,7 @@ last = { optional = true, version = "0.0.1", package = "uu_last", path = "src/uu
lscpu = { optional = true, version = "0.0.1", package = "uu_lscpu", path = "src/uu/lscpu" }
lslocks = { optional = true, version = "0.0.1", package = "uu_lslocks", path = "src/uu/lslocks" }
lsmem = { optional = true, version = "0.0.1", package = "uu_lsmem", path = "src/uu/lsmem" }
+mesg = { optional = true, version = "0.0.1", package = "uu_mesg", path = "src/uu/mesg" }
mountpoint = { optional = true, version = "0.0.1", package = "uu_mountpoint", path = "src/uu/mountpoint" }
rev = { optional = true, version = "0.0.1", package = "uu_rev", path = "src/uu/rev" }
setsid = { optional = true, version = "0.0.1", package = "uu_setsid", path ="src/uu/setsid" }
diff --git a/src/uu/mesg/Cargo.toml b/src/uu/mesg/Cargo.toml
new file mode 100644
index 0000000..c75a4d8
--- /dev/null
+++ b/src/uu/mesg/Cargo.toml
@@ -0,0 +1,16 @@
+[package]
+name = "uu_mesg"
+version = "0.0.1"
+edition = "2021"
+
+[lib]
+path = "src/mesg.rs"
+
+[[bin]]
+name = "mesg"
+path = "src/main.rs"
+
+[dependencies]
+clap = { workspace = true }
+nix = { workspace = true }
+uucore = { workspace = true }
diff --git a/src/uu/mesg/mesg.md b/src/uu/mesg/mesg.md
new file mode 100644
index 0000000..afcb543
--- /dev/null
+++ b/src/uu/mesg/mesg.md
@@ -0,0 +1,7 @@
+# mesg
+
+```
+mesg [option] [y|n]
+```
+
+enables or disables displaying messages from other users
diff --git a/src/uu/mesg/src/main.rs b/src/uu/mesg/src/main.rs
new file mode 100644
index 0000000..aff7ec1
--- /dev/null
+++ b/src/uu/mesg/src/main.rs
@@ -0,0 +1 @@
+uucore::bin!(uu_mesg);
diff --git a/src/uu/mesg/src/mesg.rs b/src/uu/mesg/src/mesg.rs
new file mode 100644
index 0000000..220ed36
--- /dev/null
+++ b/src/uu/mesg/src/mesg.rs
@@ -0,0 +1,101 @@
+// This file is part of the uutils util-linux package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use clap::{builder::PossibleValuesParser, crate_version, Arg, ArgAction, ArgMatches, Command};
+#[cfg(target_family = "unix")]
+use uucore::error::{set_exit_code, UIoError};
+use uucore::{error::UResult, format_usage, help_about, help_usage};
+
+const ABOUT: &str = help_about!("mesg.md");
+const USAGE: &str = help_usage!("mesg.md");
+
+#[cfg(target_family = "unix")]
+pub fn do_mesg(matches: &ArgMatches) -> UResult<()> {
+ use nix::sys::stat::{fchmod, fstat, Mode};
+ use std::{io, os::fd::AsRawFd};
+ use std::{io::IsTerminal, os::fd::AsFd};
+
+ for fd in &[
+ std::io::stdin().as_fd(),
+ std::io::stdout().as_fd(),
+ std::io::stderr().as_fd(),
+ ] {
+ if fd.is_terminal() {
+ let st = fstat(fd.as_raw_fd())?;
+ if let Some(enable) = matches.get_one::<String>("enable") {
+ // 'mesg y' on the GNU version seems to only modify the group write bit,
+ // but 'mesg n' modifies both group and others write bits.
+ let new_mode = if enable == "y" {
+ st.st_mode | 0o020
+ } else {
+ st.st_mode & !0o022
+ };
+ fchmod(fd.as_raw_fd(), Mode::from_bits_retain(new_mode))?;
+ if enable == "n" {
+ set_exit_code(1);
+ }
+ if matches.get_flag("verbose") {
+ println!(
+ "write access to your terminal is {}",
+ if enable == "y" { "allowed" } else { "denied" }
+ );
+ }
+ } else if st.st_mode & 0o022 != 0 {
+ println!("is y");
+ } else {
+ set_exit_code(1);
+ println!("is n");
+ }
+ return Ok(());
+ }
+ }
+ Err(UIoError::new(
+ io::ErrorKind::Other,
+ "stdin/stdout/stderr is not a terminal",
+ ))
+}
+
+#[cfg(target_family = "unix")]
+#[uucore::main]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+ let matches = uu_app().try_get_matches_from(args)?;
+ if let Err(e) = do_mesg(&matches) {
+ set_exit_code(2);
+ uucore::show_error!("{}", e);
+ };
+ Ok(())
+}
+
+pub fn uu_app() -> Command {
+ Command::new(uucore::util_name())
+ .version(crate_version!())
+ .about(ABOUT)
+ .override_usage(format_usage(USAGE))
+ .infer_long_args(true)
+ .arg(
+ Arg::new("verbose")
+ .short('v')
+ .long("verbose")
+ .help("Explain what is being done")
+ .action(ArgAction::SetTrue),
+ )
+ .arg(
+ Arg::new("enable")
+ .help("Whether to allow or disallow messages")
+ .value_parser(PossibleValuesParser::new(["y", "n"]))
+ .action(ArgAction::Set),
+ )
+}
+
+#[cfg(not(target_family = "unix"))]
+#[uucore::main]
+pub fn uumain(args: impl uucore::Args) -> UResult<()> {
+ let _matches: ArgMatches = uu_app().try_get_matches_from(args)?;
+
+ Err(uucore::error::USimpleError::new(
+ 1,
+ "`mesg` is available only on Unix platforms.",
+ ))
+}
diff --git a/tests/by-util/test_mesg.rs b/tests/by-util/test_mesg.rs
new file mode 100644
index 0000000..7715a8d
--- /dev/null
+++ b/tests/by-util/test_mesg.rs
@@ -0,0 +1,36 @@
+// This file is part of the uutils util-linux package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use crate::common::util::TestScenario;
+
+#[test]
+fn test_invalid_verb() {
+ new_ucmd!().arg("foo").fails().code_is(1);
+}
+
+#[test]
+#[cfg(target_family = "unix")]
+fn test_no_terminal() {
+ for args in &[vec![], vec!["y"], vec!["n"]] {
+ new_ucmd!()
+ .args(args)
+ .fails()
+ .code_is(2)
+ .stderr_contains("stdin/stdout/stderr is not a terminal");
+ }
+}
+
+#[cfg(not(target_family = "unix"))]
+mod non_unix {
+ use crate::common::util::TestScenario;
+
+ #[test]
+ fn test_fails_on_unsupported_platforms() {
+ new_ucmd!()
+ .fails()
+ .code_is(1)
+ .stderr_is("mesg: `mesg` is available only on Unix platforms.\n");
+ }
+}
diff --git a/tests/tests.rs b/tests/tests.rs
index ae15cde..8d72ee6 100644
--- a/tests/tests.rs
+++ b/tests/tests.rs
@@ -17,6 +17,10 @@ mod test_lsmem;
#[path = "by-util/test_lslocks.rs"]
mod test_lslocks;
+#[cfg(feature = "mesg")]
+#[path = "by-util/test_mesg.rs"]
+mod test_mesg;
+
#[cfg(feature = "mountpoint")]
#[path = "by-util/test_mountpoint.rs"]
mod test_mountpoint;