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// Copyright 2014 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.
// Test that SIGSETXID runs on signal stack, since it's likely to
// overflow if it runs on the Go stack.
package cgotest
/*
#include <sys/types.h>
#include <unistd.h>
*/
import "C"
import (
"runtime"
"runtime/debug"
"sync/atomic"
"testing"
"misc/cgo/test/issue9400"
)
func test9400(t *testing.T) {
// We synchronize through a shared variable, so we need two procs
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
// Start signaller
atomic.StoreInt32(&issue9400.Baton, 0)
go func() {
// Wait for RewindAndSetgid
for atomic.LoadInt32(&issue9400.Baton) == 0 {
runtime.Gosched()
}
// Broadcast SIGSETXID
runtime.LockOSThread()
C.setgid(0)
// Indicate that signalling is done
atomic.StoreInt32(&issue9400.Baton, 0)
}()
// Grow the stack and put down a test pattern
const pattern = 0x123456789abcdef
var big [1024]uint64 // len must match assembly
for i := range big {
big[i] = pattern
}
// Disable GC for the duration of the test.
// This avoids a potential GC deadlock when spinning in uninterruptable ASM below #49695.
defer debug.SetGCPercent(debug.SetGCPercent(-1))
// SetGCPercent waits until the mark phase is over, but the runtime
// also preempts at the start of the sweep phase, so make sure that's
// done too. See #49695.
runtime.GC()
// Temporarily rewind the stack and trigger SIGSETXID
issue9400.RewindAndSetgid()
// Check test pattern
for i := range big {
if big[i] != pattern {
t.Fatalf("entry %d of test pattern is wrong; %#x != %#x", i, big[i], uint64(pattern))
}
}
}
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