1# nocrash.m4 serial 5
2dnl Copyright (C) 2005, 2009-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl Based on libsigsegv, from Bruno Haible and Paolo Bonzini.
8
9AC_PREREQ([2.13])
10
11dnl Expands to some code for use in .c programs that will cause the configure
12dnl test to exit instead of crashing. This is useful to avoid triggering
13dnl action from a background debugger and to avoid core dumps.
14dnl Usage:   ...
15dnl          ]GL_NOCRASH[
16dnl          ...
17dnl          int main() { nocrash_init(); ... }
18AC_DEFUN([GL_NOCRASH],[[
19#include <stdlib.h>
20#if defined __MACH__ && defined __APPLE__
21/* Avoid a crash on Mac OS X.  */
22#include <mach/mach.h>
23#include <mach/mach_error.h>
24#include <mach/thread_status.h>
25#include <mach/exception.h>
26#include <mach/task.h>
27#include <pthread.h>
28/* The exception port on which our thread listens.  */
29static mach_port_t our_exception_port;
30/* The main function of the thread listening for exceptions of type
31   EXC_BAD_ACCESS.  */
32static void *
33mach_exception_thread (void *arg)
34{
35  /* Buffer for a message to be received.  */
36  struct {
37    mach_msg_header_t head;
38    mach_msg_body_t msgh_body;
39    char data[1024];
40  } msg;
41  mach_msg_return_t retval;
42  /* Wait for a message on the exception port.  */
43  retval = mach_msg (&msg.head, MACH_RCV_MSG | MACH_RCV_LARGE, 0, sizeof (msg),
44                     our_exception_port, MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
45  if (retval != MACH_MSG_SUCCESS)
46    abort ();
47  exit (1);
48}
49static void
50nocrash_init (void)
51{
52  mach_port_t self = mach_task_self ();
53  /* Allocate a port on which the thread shall listen for exceptions.  */
54  if (mach_port_allocate (self, MACH_PORT_RIGHT_RECEIVE, &our_exception_port)
55      == KERN_SUCCESS) {
56    /* See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/mach_port_insert_right.html.  */
57    if (mach_port_insert_right (self, our_exception_port, our_exception_port,
58                                MACH_MSG_TYPE_MAKE_SEND)
59        == KERN_SUCCESS) {
60      /* The exceptions we want to catch.  Only EXC_BAD_ACCESS is interesting
61         for us.  */
62      exception_mask_t mask = EXC_MASK_BAD_ACCESS;
63      /* Create the thread listening on the exception port.  */
64      pthread_attr_t attr;
65      pthread_t thread;
66      if (pthread_attr_init (&attr) == 0
67          && pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED) == 0
68          && pthread_create (&thread, &attr, mach_exception_thread, NULL) == 0) {
69        pthread_attr_destroy (&attr);
70        /* Replace the exception port info for these exceptions with our own.
71           Note that we replace the exception port for the entire task, not only
72           for a particular thread.  This has the effect that when our exception
73           port gets the message, the thread specific exception port has already
74           been asked, and we don't need to bother about it.
75           See https://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.  */
76        task_set_exception_ports (self, mask, our_exception_port,
77                                  EXCEPTION_DEFAULT, MACHINE_THREAD_STATE);
78      }
79    }
80  }
81}
82#elif defined _WIN32 && ! defined __CYGWIN__
83/* Avoid a crash on native Windows.  */
84#define WIN32_LEAN_AND_MEAN
85#include <windows.h>
86#include <winerror.h>
87static LONG WINAPI
88exception_filter (EXCEPTION_POINTERS *ExceptionInfo)
89{
90  switch (ExceptionInfo->ExceptionRecord->ExceptionCode)
91    {
92    case EXCEPTION_ACCESS_VIOLATION:
93    case EXCEPTION_IN_PAGE_ERROR:
94    case EXCEPTION_STACK_OVERFLOW:
95    case EXCEPTION_GUARD_PAGE:
96    case EXCEPTION_PRIV_INSTRUCTION:
97    case EXCEPTION_ILLEGAL_INSTRUCTION:
98    case EXCEPTION_DATATYPE_MISALIGNMENT:
99    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
100    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
101      exit (1);
102    }
103  return EXCEPTION_CONTINUE_SEARCH;
104}
105static void
106nocrash_init (void)
107{
108  SetUnhandledExceptionFilter ((LPTOP_LEVEL_EXCEPTION_FILTER) exception_filter);
109}
110#else
111/* Avoid a crash on POSIX systems.  */
112#include <signal.h>
113#include <unistd.h>
114/* A POSIX signal handler.  */
115static void
116exception_handler (int sig)
117{
118  _exit (1);
119}
120static void
121nocrash_init (void)
122{
123#ifdef SIGSEGV
124  signal (SIGSEGV, exception_handler);
125#endif
126#ifdef SIGBUS
127  signal (SIGBUS, exception_handler);
128#endif
129}
130#endif
131]])
132