Refactor signal handling in yes, tee, and timeout

Yes, using libc while using nix was a bit redundant.
Upon investigation, duplicated code was found and moved to uucore.

src/uu/tee/src/tee.rs

@@ -16,7 +16,7 @@ use uucore::{format_usage, help_about, help_section, help_usage, show_error};
 // spell-checker:ignore nopipe
 
 #[cfg(unix)]
-use uucore::libc;
+use uucore::signals::{enable_pipe_errors, ignore_interrupts};
 
 const ABOUT: &str = help_about!("tee.md");
 const USAGE: &str = help_usage!("tee.md");
@@ -135,44 +135,19 @@ pub fn uu_app() -> Command {
         )
 }
 
-#[cfg(unix)]
-fn ignore_interrupts() -> Result<()> {
-    let ret = unsafe { libc::signal(libc::SIGINT, libc::SIG_IGN) };
-    if ret == libc::SIG_ERR {
-        return Err(Error::new(ErrorKind::Other, ""));
-    }
-    Ok(())
-}
-
-#[cfg(not(unix))]
-fn ignore_interrupts() -> Result<()> {
-    // Do nothing.
-    Ok(())
-}
-
-#[cfg(unix)]
-fn enable_pipe_errors() -> Result<()> {
-    let ret = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_DFL) };
-    if ret == libc::SIG_ERR {
-        return Err(Error::new(ErrorKind::Other, ""));
-    }
-    Ok(())
-}
-
-#[cfg(not(unix))]
-fn enable_pipe_errors() -> Result<()> {
-    // Do nothing.
-    Ok(())
-}
-
 fn tee(options: &Options) -> Result<()> {
-    if options.ignore_interrupts {
-        ignore_interrupts()?;
-    }
-    if options.output_error.is_none() {
-        enable_pipe_errors()?;
-    }
+    #[cfg(unix)]
+    {
+        // ErrorKind::Other is raised by MultiWriter when all writers have exited.
+        // This is therefore just a clever way to stop all writers
 
+        if options.ignore_interrupts {
+            ignore_interrupts().map_err(|_| Error::from(ErrorKind::Other))?;
+        }
+        if options.output_error.is_none() {
+            enable_pipe_errors().map_err(|_| Error::from(ErrorKind::Other))?;
+        }
+    }
     let mut writers: Vec<NamedWriter> = options
         .files
         .clone()

src/uu/timeout/src/timeout.rs

@@ -17,8 +17,14 @@ use std::time::Duration;
 use uucore::display::Quotable;
 use uucore::error::{UClapError, UResult, USimpleError, UUsageError};
 use uucore::process::ChildExt;
-use uucore::signals::{signal_by_name_or_value, signal_name_by_value};
-use uucore::{format_usage, show_error};
+
+#[cfg(unix)]
+use uucore::signals::enable_pipe_errors;
+
+use uucore::{
+    format_usage, show_error,
+    signals::{signal_by_name_or_value, signal_name_by_value},
+};
 
 static ABOUT: &str = "Start COMMAND, and kill it if still running after DURATION.";
 const USAGE: &str = "{} [OPTION] DURATION COMMAND...";
@@ -285,21 +291,6 @@ fn preserve_signal_info(signal: libc::c_int) -> libc::c_int {
     signal
 }
 
-#[cfg(unix)]
-fn enable_pipe_errors() -> std::io::Result<()> {
-    let ret = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_DFL) };
-    if ret == libc::SIG_ERR {
-        return Err(std::io::Error::new(std::io::ErrorKind::Other, ""));
-    }
-    Ok(())
-}
-
-#[cfg(not(unix))]
-fn enable_pipe_errors() -> std::io::Result<()> {
-    // Do nothing.
-    Ok(())
-}
-
 /// TODO: Improve exit codes, and make them consistent with the GNU Coreutils exit codes.
 
 fn timeout(
@@ -314,7 +305,7 @@ fn timeout(
     if !foreground {
         unsafe { libc::setpgid(0, 0) };
     }
-
+    #[cfg(unix)]
     enable_pipe_errors()?;
 
     let process = &mut process::Command::new(&cmd[0])

src/uu/yes/Cargo.toml

@@ -16,12 +16,14 @@ path = "src/yes.rs"
 
 [dependencies]
 clap = { workspace=true }
-libc = { workspace=true }
-uucore = { workspace=true, features=["pipes"] }
 
-[target.'cfg(any(target_os = "linux", target_os = "android"))'.dependencies]
+[target.'cfg(unix)'.dependencies]
+uucore = { workspace=true, features=["pipes", "signals"] }
 nix = { workspace=true }
 
+[target.'cfg(not(unix))'.dependencies]
+uucore = { workspace=true, features=["pipes"] }
+
 [[bin]]
 name = "yes"
 path = "src/main.rs"

src/uu/yes/src/yes.rs

@@ -7,13 +7,13 @@
 
 /* last synced with: yes (GNU coreutils) 8.13 */
 
-use std::borrow::Cow;
-use std::io::{self, Result, Write};
-
 use clap::{Arg, ArgAction, Command};
+use std::borrow::Cow;
+use std::io::{self, Write};
 use uucore::error::{UResult, USimpleError};
+#[cfg(unix)]
+use uucore::signals::enable_pipe_errors;
 use uucore::{format_usage, help_about, help_usage};
-
 #[cfg(any(target_os = "linux", target_os = "android"))]
 mod splice;
 
@@ -69,25 +69,10 @@ fn prepare_buffer<'a>(input: &'a str, buffer: &'a mut [u8; BUF_SIZE]) -> &'a [u8
     }
 }
 
-#[cfg(unix)]
-fn enable_pipe_errors() -> Result<()> {
-    let ret = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_DFL) };
-    if ret == libc::SIG_ERR {
-        return Err(io::Error::new(io::ErrorKind::Other, ""));
-    }
-    Ok(())
-}
-
-#[cfg(not(unix))]
-fn enable_pipe_errors() -> Result<()> {
-    // Do nothing.
-    Ok(())
-}
-
 pub fn exec(bytes: &[u8]) -> io::Result<()> {
     let stdout = io::stdout();
     let mut stdout = stdout.lock();
-
+    #[cfg(unix)]
     enable_pipe_errors()?;
 
     #[cfg(any(target_os = "linux", target_os = "android"))]

src/uucore/Cargo.toml

@@ -49,7 +49,7 @@ sm3 = { workspace=true }
 
 [target.'cfg(unix)'.dependencies]
 walkdir = { workspace=true, optional=true }
-nix = { workspace=true, features = ["fs", "uio", "zerocopy"] }
+nix = { workspace=true, features = ["fs", "uio", "zerocopy", "signal"] }
 
 [dev-dependencies]
 clap = { workspace=true }

src/uucore/src/lib/features/signals.rs

@@ -7,7 +7,12 @@
 
 // spell-checker:ignore (vars/api) fcntl setrlimit setitimer
 // spell-checker:ignore (vars/signals) ABRT ALRM CHLD SEGV SIGABRT SIGALRM SIGBUS SIGCHLD SIGCONT SIGEMT SIGFPE SIGHUP SIGILL SIGINFO SIGINT SIGIO SIGIOT SIGKILL SIGPIPE SIGPROF SIGPWR SIGQUIT SIGSEGV SIGSTOP SIGSYS SIGTERM SIGTRAP SIGTSTP SIGTHR SIGTTIN SIGTTOU SIGURG SIGUSR SIGVTALRM SIGWINCH SIGXCPU SIGXFSZ STKFLT PWR THR TSTP TTIN TTOU VTALRM XCPU XFSZ
-
+#[cfg(unix)]
+use nix::errno::Errno;
+#[cfg(unix)]
+use nix::sys::signal::{
+    signal, SigHandler::SigDfl, SigHandler::SigIgn, Signal::SIGINT, Signal::SIGPIPE,
+};
 pub static DEFAULT_SIGNAL: usize = 15;
 
 /*
@@ -196,6 +201,19 @@ pub fn signal_name_by_value(signal_value: usize) -> Option<&'static str> {
     ALL_SIGNALS.get(signal_value).copied()
 }
 
+#[cfg(unix)]
+pub fn enable_pipe_errors() -> Result<(), Errno> {
+    // We pass the error as is, the return value would just be Ok(SigDfl), so we can safely ignore it.
+    // SAFETY: this function is safe as long as we do not use a custom SigHandler -- we use the default one.
+    unsafe { signal(SIGPIPE, SigDfl) }.map(|_| ())
+}
+#[cfg(unix)]
+pub fn ignore_interrupts() -> Result<(), Errno> {
+    // We pass the error as is, the return value would just be Ok(SigIgn) so we can safely ignore it.
+    // SAFETY: this function is safe as long as we do not use a custom SigHandler -- we use the default one.
+    unsafe { signal(SIGINT, SigIgn) }.map(|_| ())
+}
+
 #[test]
 fn signal_by_value() {
     assert_eq!(signal_by_name_or_value("0"), Some(0));