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Packit |
33f14e |
# Check prerequisites for compiling lib/c-stack.c.
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Packit |
33f14e |
|
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Packit |
33f14e |
# Copyright (C) 2002-2004, 2008-2017 Free Software Foundation, Inc.
|
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Packit |
33f14e |
# This file is free software; the Free Software Foundation
|
|
Packit |
33f14e |
# gives unlimited permission to copy and/or distribute it,
|
|
Packit |
33f14e |
# with or without modifications, as long as this notice is preserved.
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|
Packit |
33f14e |
|
|
Packit |
33f14e |
# Written by Paul Eggert.
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Packit |
33f14e |
|
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Packit |
33f14e |
# serial 15
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
|
|
Packit |
33f14e |
[
|
|
Packit |
33f14e |
AC_REQUIRE([AC_CANONICAL_HOST])
|
|
Packit |
33f14e |
AC_CHECK_FUNCS_ONCE([setrlimit])
|
|
Packit |
33f14e |
AC_CHECK_HEADERS_ONCE([ucontext.h])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
dnl List of signals that are sent when an invalid virtual memory address
|
|
Packit |
33f14e |
dnl is accessed, or when the stack overflows.
|
|
Packit |
33f14e |
dnl Either { SIGSEGV } or { SIGSEGV, SIGBUS }.
|
|
Packit |
33f14e |
case "$host_os" in
|
|
Packit |
33f14e |
sunos4* | freebsd* | dragonfly* | openbsd* | mirbsd* | netbsd* | kfreebsd* | knetbsd*) # BSD systems
|
|
Packit |
33f14e |
FAULT_YIELDS_SIGBUS=1 ;;
|
|
Packit |
33f14e |
hpux*) # HP-UX
|
|
Packit |
33f14e |
FAULT_YIELDS_SIGBUS=1 ;;
|
|
Packit |
33f14e |
macos* | darwin*) # Mac OS X
|
|
Packit |
33f14e |
FAULT_YIELDS_SIGBUS=1 ;;
|
|
Packit |
33f14e |
gnu*) # Hurd
|
|
Packit |
33f14e |
FAULT_YIELDS_SIGBUS=1 ;;
|
|
Packit |
33f14e |
*)
|
|
Packit |
33f14e |
FAULT_YIELDS_SIGBUS=0 ;;
|
|
Packit |
33f14e |
esac
|
|
Packit |
33f14e |
AC_DEFINE_UNQUOTED([FAULT_YIELDS_SIGBUS], [$FAULT_YIELDS_SIGBUS],
|
|
Packit |
33f14e |
[Define to 1 if an invalid memory address access may yield a SIGBUS.])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_CACHE_CHECK([for working C stack overflow detection],
|
|
Packit |
33f14e |
[ac_cv_sys_stack_overflow_works],
|
|
Packit |
33f14e |
[AC_RUN_IFELSE([AC_LANG_SOURCE(
|
|
Packit |
33f14e |
[[
|
|
Packit |
33f14e |
#include <unistd.h>
|
|
Packit |
33f14e |
#include <signal.h>
|
|
Packit |
33f14e |
#if HAVE_SETRLIMIT
|
|
Packit |
33f14e |
# include <sys/types.h>
|
|
Packit |
33f14e |
# include <sys/time.h>
|
|
Packit |
33f14e |
# include <sys/resource.h>
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
#ifndef SIGSTKSZ
|
|
Packit |
33f14e |
# define SIGSTKSZ 16384
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static union
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
char buffer[2 * SIGSTKSZ];
|
|
Packit |
33f14e |
long double ld;
|
|
Packit |
33f14e |
long u;
|
|
Packit |
33f14e |
void *p;
|
|
Packit |
33f14e |
} alternate_signal_stack;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static void
|
|
Packit |
33f14e |
segv_handler (int signo)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
_exit (0);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static int
|
|
Packit |
33f14e |
c_stack_action ()
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
stack_t st;
|
|
Packit |
33f14e |
struct sigaction act;
|
|
Packit |
33f14e |
int r;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
st.ss_flags = 0;
|
|
Packit |
33f14e |
/* Use the midpoint to avoid Irix sigaltstack bug. */
|
|
Packit |
33f14e |
st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
|
|
Packit |
33f14e |
st.ss_size = SIGSTKSZ;
|
|
Packit |
33f14e |
r = sigaltstack (&st, 0);
|
|
Packit |
33f14e |
if (r != 0)
|
|
Packit |
33f14e |
return 1;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
sigemptyset (&act.sa_mask);
|
|
Packit |
33f14e |
act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
|
|
Packit |
33f14e |
act.sa_handler = segv_handler;
|
|
Packit |
33f14e |
#if FAULT_YIELDS_SIGBUS
|
|
Packit |
33f14e |
if (sigaction (SIGBUS, &act, 0) < 0)
|
|
Packit |
33f14e |
return 2;
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
if (sigaction (SIGSEGV, &act, 0) < 0)
|
|
Packit |
33f14e |
return 3;
|
|
Packit |
33f14e |
return 0;
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
static volatile int *
|
|
Packit |
33f14e |
recurse_1 (volatile int n, volatile int *p)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
if (n >= 0)
|
|
Packit |
33f14e |
*recurse_1 (n + 1, p) += n;
|
|
Packit |
33f14e |
return p;
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
static int
|
|
Packit |
33f14e |
recurse (volatile int n)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
int sum = 0;
|
|
Packit |
33f14e |
return *recurse_1 (n, &sum);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
int
|
|
Packit |
33f14e |
main ()
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
int result;
|
|
Packit |
33f14e |
#if HAVE_SETRLIMIT && defined RLIMIT_STACK
|
|
Packit |
33f14e |
/* Before starting the endless recursion, try to be friendly
|
|
Packit |
33f14e |
to the user's machine. On some Linux 2.2.x systems, there
|
|
Packit |
33f14e |
is no stack limit for user processes at all. We don't want
|
|
Packit |
33f14e |
to kill such systems. */
|
|
Packit |
33f14e |
struct rlimit rl;
|
|
Packit |
33f14e |
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
|
|
Packit |
33f14e |
setrlimit (RLIMIT_STACK, &rl);
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
result = c_stack_action ();
|
|
Packit |
33f14e |
if (result != 0)
|
|
Packit |
33f14e |
return result;
|
|
Packit |
33f14e |
return recurse (0);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
]])],
|
|
Packit |
33f14e |
[ac_cv_sys_stack_overflow_works=yes],
|
|
Packit |
33f14e |
[ac_cv_sys_stack_overflow_works=no],
|
|
Packit |
33f14e |
[ac_cv_sys_stack_overflow_works=cross-compiling])])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
if test $ac_cv_sys_stack_overflow_works = yes; then
|
|
Packit |
33f14e |
AC_DEFINE([HAVE_STACK_OVERFLOW_HANDLING], [1],
|
|
Packit |
33f14e |
[Define to 1 if extending the stack slightly past the limit causes
|
|
Packit |
33f14e |
a SIGSEGV which can be handled on an alternate stack established
|
|
Packit |
33f14e |
with sigaltstack.])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
dnl The ss_sp field of a stack_t is, according to POSIX, the lowest address
|
|
Packit |
33f14e |
dnl of the memory block designated as an alternate stack. But IRIX 5.3
|
|
Packit |
33f14e |
dnl interprets it as the highest address!
|
|
Packit |
33f14e |
AC_CACHE_CHECK([for correct stack_t interpretation],
|
|
Packit |
33f14e |
[gl_cv_sigaltstack_low_base], [
|
|
Packit |
33f14e |
AC_RUN_IFELSE([
|
|
Packit |
33f14e |
AC_LANG_SOURCE([[
|
|
Packit |
33f14e |
#include <stdlib.h>
|
|
Packit |
33f14e |
#include <signal.h>
|
|
Packit |
33f14e |
#if HAVE_SYS_SIGNAL_H
|
|
Packit |
33f14e |
# include <sys/signal.h>
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
#ifndef SIGSTKSZ
|
|
Packit |
33f14e |
# define SIGSTKSZ 16384
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
volatile char *stack_lower_bound;
|
|
Packit |
33f14e |
volatile char *stack_upper_bound;
|
|
Packit |
33f14e |
static void check_stack_location (volatile char *addr)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
if (addr >= stack_lower_bound && addr <= stack_upper_bound)
|
|
Packit |
33f14e |
exit (0);
|
|
Packit |
33f14e |
else
|
|
Packit |
33f14e |
exit (1);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
static void stackoverflow_handler (int sig)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
char dummy;
|
|
Packit |
33f14e |
check_stack_location (&dummy);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
int main ()
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
char mystack[2 * SIGSTKSZ];
|
|
Packit |
33f14e |
stack_t altstack;
|
|
Packit |
33f14e |
struct sigaction action;
|
|
Packit |
33f14e |
/* Install the alternate stack. */
|
|
Packit |
33f14e |
altstack.ss_sp = mystack + SIGSTKSZ;
|
|
Packit |
33f14e |
altstack.ss_size = SIGSTKSZ;
|
|
Packit |
33f14e |
stack_lower_bound = (char *) altstack.ss_sp;
|
|
Packit |
33f14e |
stack_upper_bound = (char *) altstack.ss_sp + altstack.ss_size - 1;
|
|
Packit |
33f14e |
altstack.ss_flags = 0; /* no SS_DISABLE */
|
|
Packit |
33f14e |
if (sigaltstack (&altstack, NULL) < 0)
|
|
Packit |
33f14e |
exit (2);
|
|
Packit |
33f14e |
/* Install the SIGSEGV handler. */
|
|
Packit |
33f14e |
sigemptyset (&action.sa_mask);
|
|
Packit |
33f14e |
action.sa_handler = &stackoverflow_handler;
|
|
Packit |
33f14e |
action.sa_flags = SA_ONSTACK;
|
|
Packit |
33f14e |
if (sigaction (SIGSEGV, &action, (struct sigaction *) NULL) < 0)
|
|
Packit |
33f14e |
exit(3);
|
|
Packit |
33f14e |
/* Provoke a SIGSEGV. */
|
|
Packit |
33f14e |
raise (SIGSEGV);
|
|
Packit |
33f14e |
exit (4);
|
|
Packit |
33f14e |
}]])],
|
|
Packit |
33f14e |
[gl_cv_sigaltstack_low_base=yes],
|
|
Packit |
33f14e |
[gl_cv_sigaltstack_low_base=no],
|
|
Packit |
33f14e |
[gl_cv_sigaltstack_low_base=cross-compiling])])
|
|
Packit |
33f14e |
if test "$gl_cv_sigaltstack_low_base" = no; then
|
|
Packit |
33f14e |
AC_DEFINE([SIGALTSTACK_SS_REVERSED], [1],
|
|
Packit |
33f14e |
[Define if sigaltstack() interprets the stack_t.ss_sp field
|
|
Packit |
33f14e |
incorrectly, as the highest address of the alternate stack range
|
|
Packit |
33f14e |
rather than as the lowest address.])
|
|
Packit |
33f14e |
fi
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_CACHE_CHECK([for precise C stack overflow detection],
|
|
Packit |
33f14e |
ac_cv_sys_xsi_stack_overflow_heuristic,
|
|
Packit |
33f14e |
[AC_RUN_IFELSE([AC_LANG_SOURCE(
|
|
Packit |
33f14e |
[[
|
|
Packit |
33f14e |
#include <unistd.h>
|
|
Packit |
33f14e |
#include <signal.h>
|
|
Packit |
33f14e |
#if HAVE_UCONTEXT_H
|
|
Packit |
33f14e |
# include <ucontext.h>
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
#if HAVE_SETRLIMIT
|
|
Packit |
33f14e |
# include <sys/types.h>
|
|
Packit |
33f14e |
# include <sys/time.h>
|
|
Packit |
33f14e |
# include <sys/resource.h>
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
#ifndef SIGSTKSZ
|
|
Packit |
33f14e |
# define SIGSTKSZ 16384
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static union
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
char buffer[2 * SIGSTKSZ];
|
|
Packit |
33f14e |
long double ld;
|
|
Packit |
33f14e |
long u;
|
|
Packit |
33f14e |
void *p;
|
|
Packit |
33f14e |
} alternate_signal_stack;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
#if STACK_DIRECTION
|
|
Packit |
33f14e |
# define find_stack_direction(ptr) STACK_DIRECTION
|
|
Packit |
33f14e |
#else
|
|
Packit |
33f14e |
static int
|
|
Packit |
33f14e |
find_stack_direction (char const *addr)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
char dummy;
|
|
Packit |
33f14e |
return (! addr ? find_stack_direction (&dummy)
|
|
Packit |
33f14e |
: addr < &dummy ? 1 : -1);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static void
|
|
Packit |
33f14e |
segv_handler (int signo, siginfo_t *info, void *context)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
if (0 < info->si_code)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
/* For XSI heuristics to work, we need uc_stack to describe
|
|
Packit |
33f14e |
the interrupted stack (as on Solaris), and not the
|
|
Packit |
33f14e |
currently executing stack (as on Linux). */
|
|
Packit |
33f14e |
ucontext_t const *user_context = context;
|
|
Packit |
33f14e |
char const *stack_min = user_context->uc_stack.ss_sp;
|
|
Packit |
33f14e |
size_t stack_size = user_context->uc_stack.ss_size;
|
|
Packit |
33f14e |
char const *faulting_address = info->si_addr;
|
|
Packit |
33f14e |
size_t s = faulting_address - stack_min;
|
|
Packit |
33f14e |
size_t page_size = sysconf (_SC_PAGESIZE);
|
|
Packit |
33f14e |
if (find_stack_direction (0) < 0)
|
|
Packit |
33f14e |
s += page_size;
|
|
Packit |
33f14e |
if (s < stack_size + page_size)
|
|
Packit |
33f14e |
_exit (0);
|
|
Packit |
33f14e |
_exit (4);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
_exit (5);
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
static int
|
|
Packit |
33f14e |
c_stack_action ()
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
stack_t st;
|
|
Packit |
33f14e |
struct sigaction act;
|
|
Packit |
33f14e |
int r;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
st.ss_flags = 0;
|
|
Packit |
33f14e |
/* Use the midpoint to avoid Irix sigaltstack bug. */
|
|
Packit |
33f14e |
st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
|
|
Packit |
33f14e |
st.ss_size = SIGSTKSZ;
|
|
Packit |
33f14e |
r = sigaltstack (&st, 0);
|
|
Packit |
33f14e |
if (r != 0)
|
|
Packit |
33f14e |
return 1;
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
sigemptyset (&act.sa_mask);
|
|
Packit |
33f14e |
act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
|
|
Packit |
33f14e |
act.sa_sigaction = segv_handler;
|
|
Packit |
33f14e |
#if FAULT_YIELDS_SIGBUS
|
|
Packit |
33f14e |
if (sigaction (SIGBUS, &act, 0) < 0)
|
|
Packit |
33f14e |
return 2;
|
|
Packit |
33f14e |
#endif
|
|
Packit |
33f14e |
if (sigaction (SIGSEGV, &act, 0) < 0)
|
|
Packit |
33f14e |
return 3;
|
|
Packit |
33f14e |
return 0;
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
static volatile int *
|
|
Packit |
33f14e |
recurse_1 (volatile int n, volatile int *p)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
if (n >= 0)
|
|
Packit |
33f14e |
*recurse_1 (n + 1, p) += n;
|
|
Packit |
33f14e |
return p;
|
|
Packit |
33f14e |
}
|
|
Packit |
33f14e |
static int
|
|
Packit |
33f14e |
recurse (volatile int n)
|
|
Packit |
33f14e |
{
|
|
Packit |
33f14e |
int sum = 0;
|
|
Packit |
33f14e |
return *recurse_1 (n, &sum);
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33f14e |
}
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Packit |
33f14e |
int
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Packit |
33f14e |
main ()
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Packit |
33f14e |
{
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Packit |
33f14e |
int result;
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Packit |
33f14e |
#if HAVE_SETRLIMIT && defined RLIMIT_STACK
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Packit |
33f14e |
/* Before starting the endless recursion, try to be friendly
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Packit |
33f14e |
to the user's machine. On some Linux 2.2.x systems, there
|
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Packit |
33f14e |
is no stack limit for user processes at all. We don't want
|
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Packit |
33f14e |
to kill such systems. */
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Packit |
33f14e |
struct rlimit rl;
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Packit |
33f14e |
rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
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Packit |
33f14e |
setrlimit (RLIMIT_STACK, &rl);
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Packit |
33f14e |
#endif
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Packit |
33f14e |
|
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Packit |
33f14e |
result = c_stack_action ();
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Packit |
33f14e |
if (result != 0)
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Packit |
33f14e |
return result;
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Packit |
33f14e |
return recurse (0);
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|
Packit |
33f14e |
}
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Packit |
33f14e |
]])],
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33f14e |
[ac_cv_sys_xsi_stack_overflow_heuristic=yes],
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Packit |
33f14e |
[ac_cv_sys_xsi_stack_overflow_heuristic=no],
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Packit |
33f14e |
[ac_cv_sys_xsi_stack_overflow_heuristic=cross-compiling])])
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Packit |
33f14e |
|
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Packit |
33f14e |
if test $ac_cv_sys_xsi_stack_overflow_heuristic = yes; then
|
|
Packit |
33f14e |
AC_DEFINE([HAVE_XSI_STACK_OVERFLOW_HEURISTIC], [1],
|
|
Packit |
33f14e |
[Define to 1 if extending the stack slightly past the limit causes
|
|
Packit |
33f14e |
a SIGSEGV, and an alternate stack can be established with sigaltstack,
|
|
Packit |
33f14e |
and the signal handler is passed a context that specifies the
|
|
Packit |
33f14e |
run time stack. This behavior is defined by POSIX 1003.1-2001
|
|
Packit |
33f14e |
with the X/Open System Interface (XSI) option
|
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Packit |
33f14e |
and is a standardized way to implement a SEGV-based stack
|
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Packit |
33f14e |
overflow detection heuristic.])
|
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Packit |
33f14e |
fi
|
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Packit |
33f14e |
fi])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_DEFUN([gl_PREREQ_C_STACK],
|
|
Packit |
33f14e |
[AC_REQUIRE([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC])
|
|
Packit |
33f14e |
AC_REQUIRE([gl_LIBSIGSEGV])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
# for STACK_DIRECTION
|
|
Packit |
33f14e |
AC_REQUIRE([AC_FUNC_ALLOCA])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_CHECK_FUNCS_ONCE([sigaltstack])
|
|
Packit |
33f14e |
AC_CHECK_DECLS([sigaltstack], , , [[#include <signal.h>]])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_CHECK_HEADERS_ONCE([unistd.h ucontext.h])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_CHECK_TYPES([stack_t], , , [#include <signal.h>])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
dnl c-stack does not need -lsigsegv if the system has XSI heuristics.
|
|
Packit |
33f14e |
if test "$gl_cv_lib_sigsegv" = yes \
|
|
Packit |
33f14e |
&& test $"ac_cv_sys_xsi_stack_overflow_heuristic" != yes ; then
|
|
Packit |
33f14e |
AC_SUBST([LIBCSTACK], [$LIBSIGSEGV])
|
|
Packit |
33f14e |
AC_SUBST([LTLIBCSTACK], [$LTLIBSIGSEGV])
|
|
Packit |
33f14e |
fi
|
|
Packit |
33f14e |
])
|
|
Packit |
33f14e |
|
|
Packit |
33f14e |
AC_DEFUN([gl_C_STACK],
|
|
Packit |
33f14e |
[
|
|
Packit |
33f14e |
dnl Prerequisites of lib/c-stack.c.
|
|
Packit |
33f14e |
gl_PREREQ_C_STACK
|
|
Packit |
33f14e |
])
|