sigaltstack.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build !windows && !android
     6  // +build !windows,!android
     7  
     8  // Test that the Go runtime still works if C code changes the signal stack.
     9  
    10  package cgotest
    11  
    12  /*
    13  #include <signal.h>
    14  #include <stdio.h>
    15  #include <stdlib.h>
    16  #include <string.h>
    17  
    18  #ifdef _AIX
    19  // On AIX, SIGSTKSZ is too small to handle Go sighandler.
    20  #define CSIGSTKSZ 0x4000
    21  #else
    22  #define CSIGSTKSZ SIGSTKSZ
    23  #endif
    24  
    25  static stack_t oss;
    26  static char signalStack[CSIGSTKSZ];
    27  
    28  static void changeSignalStack(void) {
    29  	stack_t ss;
    30  	memset(&ss, 0, sizeof ss);
    31  	ss.ss_sp = signalStack;
    32  	ss.ss_flags = 0;
    33  	ss.ss_size = CSIGSTKSZ;
    34  	if (sigaltstack(&ss, &oss) < 0) {
    35  		perror("sigaltstack");
    36  		abort();
    37  	}
    38  }
    39  
    40  static void restoreSignalStack(void) {
    41  #if (defined(__x86_64__) || defined(__i386__)) && defined(__APPLE__)
    42  	// The Darwin C library enforces a minimum that the kernel does not.
    43  	// This is OK since we allocated this much space in mpreinit,
    44  	// it was just removed from the buffer by stackalloc.
    45  	oss.ss_size = MINSIGSTKSZ;
    46  #endif
    47  	if (sigaltstack(&oss, NULL) < 0) {
    48  		perror("sigaltstack restore");
    49  		abort();
    50  	}
    51  }
    52  
    53  static int zero(void) {
    54  	return 0;
    55  }
    56  */
    57  import "C"
    58  
    59  import (
    60  	"runtime"
    61  	"testing"
    62  )
    63  
    64  func testSigaltstack(t *testing.T) {
    65  	switch {
    66  	case runtime.GOOS == "solaris", runtime.GOOS == "illumos", runtime.GOOS == "ios" && runtime.GOARCH == "arm64":
    67  		t.Skipf("switching signal stack not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
    68  	}
    69  
    70  	C.changeSignalStack()
    71  	defer C.restoreSignalStack()
    72  	defer func() {
    73  		if recover() == nil {
    74  			t.Error("did not see expected panic")
    75  		}
    76  	}()
    77  	v := 1 / int(C.zero())
    78  	t.Errorf("unexpected success of division by zero == %d", v)
    79  }
    80
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