github.com/geraldss/go/src@v0.0.0-20210511222824-ac7d0ebfc235/runtime/testdata/testprogcgo/sigstack.go (about)

     1  // Copyright 2017 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  // +build !plan9,!windows
     6  
     7  // Test handling of Go-allocated signal stacks when calling from
     8  // C-created threads with and without signal stacks. (See issue
     9  // #22930.)
    10  
    11  package main
    12  
    13  /*
    14  #include <pthread.h>
    15  #include <signal.h>
    16  #include <stdio.h>
    17  #include <stdlib.h>
    18  #include <sys/mman.h>
    19  
    20  #ifdef _AIX
    21  // On AIX, SIGSTKSZ is too small to handle Go sighandler.
    22  #define CSIGSTKSZ 0x4000
    23  #else
    24  #define CSIGSTKSZ SIGSTKSZ
    25  #endif
    26  
    27  extern void SigStackCallback();
    28  
    29  static void* WithSigStack(void* arg __attribute__((unused))) {
    30  	// Set up an alternate system stack.
    31  	void* base = mmap(0, CSIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
    32  	if (base == MAP_FAILED) {
    33  		perror("mmap failed");
    34  		abort();
    35  	}
    36  	stack_t st = {}, ost = {};
    37  	st.ss_sp = (char*)base;
    38  	st.ss_flags = 0;
    39  	st.ss_size = CSIGSTKSZ;
    40  	if (sigaltstack(&st, &ost) < 0) {
    41  		perror("sigaltstack failed");
    42  		abort();
    43  	}
    44  
    45  	// Call Go.
    46  	SigStackCallback();
    47  
    48  	// Disable signal stack and protect it so we can detect reuse.
    49  	if (ost.ss_flags & SS_DISABLE) {
    50  		// Darwin libsystem has a bug where it checks ss_size
    51  		// even if SS_DISABLE is set. (The kernel gets it right.)
    52  		ost.ss_size = CSIGSTKSZ;
    53  	}
    54  	if (sigaltstack(&ost, NULL) < 0) {
    55  		perror("sigaltstack restore failed");
    56  		abort();
    57  	}
    58  	mprotect(base, CSIGSTKSZ, PROT_NONE);
    59  	return NULL;
    60  }
    61  
    62  static void* WithoutSigStack(void* arg __attribute__((unused))) {
    63  	SigStackCallback();
    64  	return NULL;
    65  }
    66  
    67  static void DoThread(int sigstack) {
    68  	pthread_t tid;
    69  	if (sigstack) {
    70  		pthread_create(&tid, NULL, WithSigStack, NULL);
    71  	} else {
    72  		pthread_create(&tid, NULL, WithoutSigStack, NULL);
    73  	}
    74  	pthread_join(tid, NULL);
    75  }
    76  */
    77  import "C"
    78  
    79  func init() {
    80  	register("SigStack", SigStack)
    81  }
    82  
    83  func SigStack() {
    84  	C.DoThread(0)
    85  	C.DoThread(1)
    86  	C.DoThread(0)
    87  	C.DoThread(1)
    88  	println("OK")
    89  }
    90  
    91  var BadPtr *int
    92  
    93  //export SigStackCallback
    94  func SigStackCallback() {
    95  	// Cause the Go signal handler to run.
    96  	defer func() { recover() }()
    97  	*BadPtr = 42
    98  }