From 1334ca42c672320cd7113cbcbc253cd93bf158b8 Mon Sep 17 00:00:00 2001
From: Bent Bisballe Nyeng <deva@aasimon.org>
Date: Thu, 30 Jan 2025 20:49:41 +0100
Subject: Correctly return errors caused bu sub-process signals such as
 segfaults and aborts.

---
 src/execute.cc       | 32 +++++++++++++++++++++++++++++---
 test/execute_test.cc |  6 ++++++
 test/testprog.cc     |  8 ++++++--
 3 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/src/execute.cc b/src/execute.cc
index 17f8714..a905efc 100644
--- a/src/execute.cc
+++ b/src/execute.cc
@@ -48,12 +48,38 @@ int parent_waitpid(pid_t pid)
 {
 	int status{};
 
-	if(waitpid(pid, &status, 0) != pid)
+	auto rc_pid = waitpid(pid, &status, 0);
+
+	if(rc_pid > 0)
 	{
-		return 1;
+		if(WIFEXITED(status))
+		{
+			// Child exited with normally
+			return WEXITSTATUS(status);
+		}
+		if(WIFSIGNALED(status))
+		{
+			// Child exited via signal (segfault, abort, ...)
+			std::cerr << strsignal(status) << '\n';
+			return WTERMSIG(status);
+		}
+	}
+	else
+	{ // No PID returned, this is an error
+		if(errno == ECHILD)
+		{
+			// No children exist.
+			return 1;
+		}
+		else
+		{
+			// Unexpected error.
+			abort();
+		}
 	}
 
-	return WEXITSTATUS(status);
+	// Should never happen...
+	return 1;
 }
 } // namespace ::
 
diff --git a/test/execute_test.cc b/test/execute_test.cc
index 4c686bf..722b6ea 100644
--- a/test/execute_test.cc
+++ b/test/execute_test.cc
@@ -35,6 +35,12 @@ public:
 		uASSERT_EQUAL(1, value);
 		value = execute(s, "no-such-binary", {}, {}, false);
 		uASSERT_EQUAL(1, value);
+		value = execute(s, cmd, {"segfault"}, {}, false);
+		uASSERT_EQUAL(11, value);
+		value = execute(s, cmd, {"throw"}, {}, false);
+		uASSERT_EQUAL(6, value);
+		value = execute(s, cmd, {"abort"}, {}, false);
+		uASSERT_EQUAL(6, value);
 	}
 
 	void env()
diff --git a/test/testprog.cc b/test/testprog.cc
index dbfb665..faf1498 100644
--- a/test/testprog.cc
+++ b/test/testprog.cc
@@ -1,8 +1,7 @@
 #include <iostream>
 #include <fstream>
 #include <string>
-
-extern const char **environ; // see 'man environ'
+#include <signal.h>
 
 int main(int argc, const char* argv[])
 {
@@ -40,6 +39,11 @@ int main(int argc, const char* argv[])
 		abort();
 	}
 
+	if(cmd == "segfault")
+	{
+		raise(SIGSEGV);
+	}
+
 	if(cmd == "throw")
 	{
 		throw "ouch";
-- 
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