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