132 lines
3.6 KiB
Plaintext
132 lines
3.6 KiB
Plaintext
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# Check prerequisites for compiling lib/c-stack.c.
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# Copyright (C) 2002 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2, or (at your option)
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# any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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# 02111-1307, USA.
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AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
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[# for STACK_DIRECTION
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AC_REQUIRE([AC_FUNC_ALLOCA])
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AC_CACHE_CHECK([for working C stack overflow detection],
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ac_cv_sys_xsi_stack_overflow_heuristic,
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[AC_TRY_RUN(
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[
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#include <signal.h>
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#include <ucontext.h>
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static union
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{
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char buffer[SIGSTKSZ];
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long double ld;
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uintmax_t u;
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void *p;
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} alternate_signal_stack;
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#if STACK_DIRECTION
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# define find_stack_direction(ptr) STACK_DIRECTION
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#else
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static int
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find_stack_direction (char const *addr)
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{
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char dummy;
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return (! addr ? find_stack_direction (&dummy)
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: addr < &dummy ? 1 : -1);
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}
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#endif
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static void
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segv_handler (int signo, siginfo_t *info, void *context)
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{
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if (0 < info->si_code)
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{
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ucontext_t const *user_context = context;
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char const *stack_min = user_context->uc_stack.ss_sp;
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size_t stack_size = user_context->uc_stack.ss_size;
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char const *faulting_address = info->si_addr;
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size_t s = faulting_address - stack_min;
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size_t page_size = sysconf (_SC_PAGESIZE);
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if (find_stack_direction (0) < 0)
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s += page_size;
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if (s < stack_size + page_size)
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_exit (0);
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}
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_exit (1);
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}
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static int
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c_stack_action (void)
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{
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stack_t st;
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struct sigaction act;
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int r;
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st.ss_flags = 0;
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st.ss_sp = alternate_signal_stack.buffer;
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st.ss_size = sizeof alternate_signal_stack.buffer;
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r = sigaltstack (&st, 0);
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if (r != 0)
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return r;
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sigemptyset (&act.sa_mask);
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act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
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act.sa_sigaction = segv_handler;
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return sigaction (SIGSEGV, &act, 0);
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}
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static int
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recurse (char *p)
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{
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char array[500];
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array[0] = 1;
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return *p + recurse (array);
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}
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int
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main (void)
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{
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c_stack_action ();
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return recurse ("\1");
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}
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],
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[ac_cv_sys_xsi_stack_overflow_heuristic=yes],
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[ac_cv_sys_xsi_stack_overflow_heuristic=no],
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[ac_cv_sys_xsi_stack_overflow_heuristic=cross-compiling])])
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if test $ac_cv_sys_xsi_stack_overflow_heuristic = yes; then
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AC_DEFINE(HAVE_XSI_STACK_OVERFLOW_HEURISTIC, 1,
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[Define to 1 if extending the stack slightly past the limit causes
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a SIGSEGV, and an alternate stack can be established with sigaltstack,
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and the signal handler is passed a context that specifies the
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run time stack. This behavior is defined by POSIX 1003.1-2001
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with the X/Open System Interface (XSI) option
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and is a standardized way to implement a SEGV-based stack
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overflow detection heuristic.])
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fi])
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AC_DEFUN([jm_PREREQ_C_STACK],
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[AC_REQUIRE([jm_AC_TYPE_UINTMAX_T])
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AC_REQUIRE([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC])
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# for STACK_DIRECTION
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AC_REQUIRE([AC_FUNC_ALLOCA])
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AC_CHECK_HEADERS(unistd.h)
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AC_CHECK_TYPES([siginfo_t, stack_t], , , [#include <signal.h>])])
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