std::process::unix: Command: Do not unwind past fork(), in child

library/std/src/sys/unix/process/process_unix.rs

@@ -1,6 +1,7 @@
 use crate::convert::TryInto;
 use crate::fmt;
 use crate::io::{self, Error, ErrorKind};
+use crate::panic;
 use crate::ptr;
 use crate::sys;
 use crate::sys::cvt;
@@ -53,7 +54,7 @@ impl Command {
 
         let pid = unsafe {
             match result {
-                0 => {
+                0 => match panic::catch_unwind(panic::AssertUnwindSafe(|| -> ! {
                     drop(input);
                     let Err(err) = self.do_exec(theirs, envp.as_ref());
                     let errno = err.raw_os_error().unwrap_or(libc::EINVAL) as u32;
@@ -73,7 +74,9 @@ impl Command {
                     // we're being torn down regardless
                     rtassert!(output.write(&bytes).is_ok());
                     libc::_exit(1)
-                }
+                })) {
+                    Err(_) => crate::process::abort(),
+                },
                 n => n,
             }
         };
@@ -533,3 +536,7 @@ impl fmt::Display for ExitStatus {
         }
     }
 }
+
+#[cfg(test)]
+#[path = "process_unix/tests.rs"]
+mod tests;

library/std/src/sys/unix/process/process_unix/tests.rs

@@ -0,0 +1,22 @@
+#[test]
+fn test_command_fork_no_unwind() {
+    use crate::os::unix::process::CommandExt;
+    use crate::os::unix::process::ExitStatusExt;
+    use crate::panic::catch_unwind;
+    use crate::process::Command;
+
+    let got = catch_unwind(|| {
+        let mut c = Command::new("echo");
+        c.arg("hi");
+        unsafe {
+            c.pre_exec(|| panic!("crash now!"));
+        }
+        let st = c.status().expect("failed to get command status");
+        eprintln!("{:?}", st);
+        st
+    });
+    eprintln!("got={:?}", &got);
+    let estatus = got.expect("panic unexpectedly propagated");
+    let signal = estatus.signal().expect("expected child to die of signal");
+    assert!(signal == libc::SIGABRT || signal == libc::SIGILL);
+}