misc/cgo/testsigfwd: move to runtime/testprog/testprogcgo

This migrates testsigfwd, which uses some one-off build
infrastructure, to be part of the runtime's testprogcgo.

The test is largely unchanged. Because it's part of a larger binary,
this CL renames a few things and gates the constructor-time signal
handler registration on an environment variable. This CL also replaces
an errant fmt.Errorf with fmt.Fprintf.

For #37486, since it eliminates a non-go-test from dist.

Change-Id: I0efd146ea0a0a3f0b361431349a419af0f0ecc61
Reviewed-on: https://go-review.googlesource.com/c/go/+/443068
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/src/runtime/testdata/testprogcgo/sigfwd.go b/src/runtime/testdata/testprogcgo/sigfwd.go
new file mode 100644
index 0000000000..1694289700
--- /dev/null
+++ b/src/runtime/testdata/testprogcgo/sigfwd.go
@@ -0,0 +1,80 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build linux
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+/*
+#include <signal.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+int *sigfwdP;
+static void sigsegv() {
+	*sigfwdP = 1;
+	fprintf(stderr, "ERROR: C SIGSEGV not thrown on caught?.\n");
+	exit(2);
+}
+
+static void segvhandler(int signum) {
+	if (signum == SIGSEGV) {
+		fprintf(stdout, "OK\n");
+		exit(0);  // success
+	}
+}
+
+static void __attribute__ ((constructor)) sigsetup(void) {
+	if (getenv("GO_TEST_CGOSIGFWD") == NULL) {
+		return;
+	}
+
+	struct sigaction act;
+
+	memset(&act, 0, sizeof act);
+	act.sa_handler = segvhandler;
+	sigaction(SIGSEGV, &act, NULL);
+}
+*/
+import "C"
+
+func init() {
+	register("CgoSigfwd", CgoSigfwd)
+}
+
+var nilPtr *byte
+
+func f() (ret bool) {
+	defer func() {
+		if recover() == nil {
+			fmt.Errorf("ERROR: couldn't raise SIGSEGV in Go.")
+			C.exit(2)
+		}
+		ret = true
+	}()
+	*nilPtr = 1
+	return false
+}
+
+func CgoSigfwd() {
+	if os.Getenv("GO_TEST_CGOSIGFWD") == "" {
+		fmt.Fprintf(os.Stderr, "test must be run with GO_TEST_CGOSIGFWD set\n")
+		os.Exit(1)
+	}
+
+	// Test that the signal originating in Go is handled (and recovered) by Go.
+	if !f() {
+		fmt.Fprintf(os.Stderr, "couldn't recover from SIGSEGV in Go.\n")
+		C.exit(2)
+	}
+
+	// Test that the signal originating in C is handled by C.
+	C.sigsegv()
+}