uucore: disable default signal-handlers added by Rust

Fixes #6759

Test procedure (verifies that a single SIGSEGV stops a program):
```
ecordonnier@lj8k2dq3:~/dev/coreutils$ ./target/release/coreutils sleep 100 &
[1] 4175464
ecordonnier@lj8k2dq3:~/dev/coreutils$ kill -11 $(pidof coreutils)
ecordonnier@lj8k2dq3:~/dev/coreutils$
[1]+  Segmentation fault      (core dumped) ./target/release/coreutils sleep 100
```

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

@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 
-// spell-checker:ignore (vars/api) fcntl setrlimit setitimer rubout pollable sysconf
+// spell-checker:ignore (vars/api) fcntl setrlimit setitimer rubout pollable sysconf sigaction
 // spell-checker:ignore (vars/signals) ABRT ALRM CHLD SEGV SIGABRT SIGALRM SIGBUS SIGCHLD SIGCONT SIGDANGER SIGEMT SIGFPE SIGHUP SIGILL SIGINFO SIGINT SIGIO SIGIOT SIGKILL SIGMIGRATE SIGMSG SIGPIPE SIGPRE SIGPROF SIGPWR SIGQUIT SIGSEGV SIGSTOP SIGSYS SIGTALRM SIGTERM SIGTRAP SIGTSTP SIGTHR SIGTTIN SIGTTOU SIGURG SIGUSR SIGVIRT SIGVTALRM SIGWINCH SIGXCPU SIGXFSZ STKFLT PWR THR TSTP TTIN TTOU VIRT VTALRM XCPU XFSZ SIGCLD SIGPOLL SIGWAITING SIGAIOCANCEL SIGLWP SIGFREEZE SIGTHAW SIGCANCEL SIGLOST SIGXRES SIGJVM SIGRTMIN SIGRT SIGRTMAX TALRM AIOCANCEL XRES RTMIN RTMAX
 
 //! This module provides a way to handle signals in a platform-independent way.
@@ -14,7 +14,8 @@
 use nix::errno::Errno;
 #[cfg(unix)]
 use nix::sys::signal::{
-    signal, SigHandler::SigDfl, SigHandler::SigIgn, Signal::SIGINT, Signal::SIGPIPE,
+    sigaction, signal, SaFlags, SigAction, SigHandler::SigDfl, SigHandler::SigIgn, SigSet,
+    Signal::SIGBUS, Signal::SIGINT, Signal::SIGPIPE, Signal::SIGSEGV,
 };
 
 /// The default signal value.
@@ -387,6 +388,25 @@ pub fn ignore_interrupts() -> Result<(), Errno> {
     unsafe { signal(SIGINT, SigIgn) }.map(|_| ())
 }
 
+// Disables the custom signal handlers installed by Rust for stack-overflow handling. With those custom signal handlers processes ignore the first SIGBUS and SIGSEGV signal they receive.
+// See https://github.com/rust-lang/rust/blob/8ac1525e091d3db28e67adcbbd6db1e1deaa37fb/src/libstd/sys/unix/stack_overflow.rs#L71-L92 for details.
+#[cfg(unix)]
+pub fn disable_rust_signal_handlers() -> Result<(), Errno> {
+    unsafe {
+        sigaction(
+            SIGSEGV,
+            &SigAction::new(SigDfl, SaFlags::empty(), SigSet::all()),
+        )
+    }?;
+    unsafe {
+        sigaction(
+            SIGBUS,
+            &SigAction::new(SigDfl, SaFlags::empty(), SigSet::all()),
+        )
+    }?;
+    Ok(())
+}
+
 #[test]
 fn signal_by_value() {
     assert_eq!(signal_by_name_or_value("0"), Some(0));

src/uucore_procs/src/lib.rs

@@ -24,6 +24,9 @@ pub fn main(_args: TokenStream, stream: TokenStream) -> TokenStream {
 
     let new = quote!(
         pub fn uumain(args: impl uucore::Args) -> i32 {
+            #[cfg(unix)]
+            uucore::signals::disable_rust_signal_handlers().expect("Disabling rust signal handlers failed");
+
             #stream
             let result = uumain(args);
             match result {