summaryrefslogtreecommitdiff
path: root/gnu/dist/diffutils/m4/c-stack.m4
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/dist/diffutils/m4/c-stack.m4')
-rw-r--r--gnu/dist/diffutils/m4/c-stack.m4131
1 files changed, 0 insertions, 131 deletions
diff --git a/gnu/dist/diffutils/m4/c-stack.m4 b/gnu/dist/diffutils/m4/c-stack.m4
deleted file mode 100644
index 0599d5023ff..00000000000
--- a/gnu/dist/diffutils/m4/c-stack.m4
+++ /dev/null
@@ -1,131 +0,0 @@
-# Check prerequisites for compiling lib/c-stack.c.
-
-# Copyright (C) 2002 Free Software Foundation, Inc.
-
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2, or (at your option)
-# any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
-# 02111-1307, USA.
-
-AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
- [# for STACK_DIRECTION
- AC_REQUIRE([AC_FUNC_ALLOCA])
-
- AC_CACHE_CHECK([for working C stack overflow detection],
- ac_cv_sys_xsi_stack_overflow_heuristic,
- [AC_TRY_RUN(
- [
- #include <signal.h>
- #include <ucontext.h>
-
- static union
- {
- char buffer[SIGSTKSZ];
- long double ld;
- uintmax_t u;
- void *p;
- } alternate_signal_stack;
-
- #if STACK_DIRECTION
- # define find_stack_direction(ptr) STACK_DIRECTION
- #else
- static int
- find_stack_direction (char const *addr)
- {
- char dummy;
- return (! addr ? find_stack_direction (&dummy)
- : addr < &dummy ? 1 : -1);
- }
- #endif
-
- static void
- segv_handler (int signo, siginfo_t *info, void *context)
- {
- if (0 < info->si_code)
- {
- ucontext_t const *user_context = context;
- char const *stack_min = user_context->uc_stack.ss_sp;
- size_t stack_size = user_context->uc_stack.ss_size;
- char const *faulting_address = info->si_addr;
- size_t s = faulting_address - stack_min;
- size_t page_size = sysconf (_SC_PAGESIZE);
- if (find_stack_direction (0) < 0)
- s += page_size;
- if (s < stack_size + page_size)
- _exit (0);
- }
-
- _exit (1);
- }
-
- static int
- c_stack_action (void)
- {
- stack_t st;
- struct sigaction act;
- int r;
-
- st.ss_flags = 0;
- st.ss_sp = alternate_signal_stack.buffer;
- st.ss_size = sizeof alternate_signal_stack.buffer;
- r = sigaltstack (&st, 0);
- if (r != 0)
- return r;
-
- sigemptyset (&act.sa_mask);
- act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
- act.sa_sigaction = segv_handler;
- return sigaction (SIGSEGV, &act, 0);
- }
-
- static int
- recurse (char *p)
- {
- char array[500];
- array[0] = 1;
- return *p + recurse (array);
- }
-
- int
- main (void)
- {
- c_stack_action ();
- return recurse ("\1");
- }
- ],
- [ac_cv_sys_xsi_stack_overflow_heuristic=yes],
- [ac_cv_sys_xsi_stack_overflow_heuristic=no],
- [ac_cv_sys_xsi_stack_overflow_heuristic=cross-compiling])])
-
- if test $ac_cv_sys_xsi_stack_overflow_heuristic = yes; then
- AC_DEFINE(HAVE_XSI_STACK_OVERFLOW_HEURISTIC, 1,
- [Define to 1 if extending the stack slightly past the limit causes
- a SIGSEGV, and an alternate stack can be established with sigaltstack,
- and the signal handler is passed a context that specifies the
- run time stack. This behavior is defined by POSIX 1003.1-2001
- with the X/Open System Interface (XSI) option
- and is a standardized way to implement a SEGV-based stack
- overflow detection heuristic.])
- fi])
-
-
-AC_DEFUN([jm_PREREQ_C_STACK],
- [AC_REQUIRE([jm_AC_TYPE_UINTMAX_T])
- AC_REQUIRE([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC])
-
- # for STACK_DIRECTION
- AC_REQUIRE([AC_FUNC_ALLOCA])
-
- AC_CHECK_HEADERS(unistd.h)
-
- AC_CHECK_TYPES([siginfo_t, stack_t], , , [#include <signal.h>])])