# Written by Paul Eggert.
-# serial 16
+# serial 17
AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
[
AC_CACHE_CHECK([for precise C stack overflow detection],
[ac_cv_sys_xsi_stack_overflow_heuristic],
- [AC_RUN_IFELSE([AC_LANG_SOURCE(
- [[
- #include <unistd.h>
- #include <signal.h>
- #if HAVE_UCONTEXT_H
- # include <ucontext.h>
- #endif
- #if HAVE_SETRLIMIT
- # include <sys/types.h>
- # include <sys/time.h>
- # include <sys/resource.h>
- #endif
- #ifndef SIGSTKSZ
- # define SIGSTKSZ 16384
- #endif
+ [dnl On Linux/sparc64 (both in 32-bit and 64-bit mode), it would be wrong
+ dnl to set HAVE_XSI_STACK_OVERFLOW_HEURISTIC to 1, because the third
+ dnl argument passed to the segv_handler is a 'struct sigcontext *', not
+ dnl an 'ucontext_t *'. It would lead to a failure of test-c-stack2.sh.
+ case "${host_os}--${host_cpu}" in
+ linux*--sparc*)
+ ac_cv_sys_xsi_stack_overflow_heuristic=no
+ ;;
+ *)
+ AC_RUN_IFELSE(
+ [AC_LANG_SOURCE(
+ [[
+ #include <unistd.h>
+ #include <signal.h>
+ #if HAVE_UCONTEXT_H
+ # include <ucontext.h>
+ #endif
+ #if HAVE_SETRLIMIT
+ # include <sys/types.h>
+ # include <sys/time.h>
+ # include <sys/resource.h>
+ #endif
+ #ifndef SIGSTKSZ
+ # define SIGSTKSZ 16384
+ #endif
- static union
- {
- char buffer[2 * SIGSTKSZ];
- long double ld;
- long u;
- void *p;
- } alternate_signal_stack;
+ static union
+ {
+ char buffer[2 * SIGSTKSZ];
+ long double ld;
+ long 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
+ #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)
+ static void
+ segv_handler (int signo, siginfo_t *info, void *context)
{
- /* For XSI heuristics to work, we need uc_stack to describe
- the interrupted stack (as on Solaris), and not the
- currently executing stack (as on Linux). */
- 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 (4);
+ if (0 < info->si_code)
+ {
+ /* For XSI heuristics to work, we need uc_stack to
+ describe the interrupted stack (as on Solaris), and
+ not the currently executing stack (as on Linux). */
+ 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 (4);
+ }
+ _exit (5);
}
- _exit (5);
- }
- static int
- c_stack_action ()
- {
- stack_t st;
- struct sigaction act;
- int r;
+ static int
+ c_stack_action ()
+ {
+ stack_t st;
+ struct sigaction act;
+ int r;
- st.ss_flags = 0;
- /* Use the midpoint to avoid Irix sigaltstack bug. */
- st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
- st.ss_size = SIGSTKSZ;
- r = sigaltstack (&st, 0);
- if (r != 0)
- return 1;
+ st.ss_flags = 0;
+ /* Use the midpoint to avoid Irix sigaltstack bug. */
+ st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
+ st.ss_size = SIGSTKSZ;
+ r = sigaltstack (&st, 0);
+ if (r != 0)
+ return 1;
- sigemptyset (&act.sa_mask);
- act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
- act.sa_sigaction = segv_handler;
- #if FAULT_YIELDS_SIGBUS
- if (sigaction (SIGBUS, &act, 0) < 0)
- return 2;
- #endif
- if (sigaction (SIGSEGV, &act, 0) < 0)
- return 3;
- return 0;
- }
- static volatile int *
- recurse_1 (volatile int n, volatile int *p)
- {
- if (n >= 0)
- *recurse_1 (n + 1, p) += n;
- return p;
- }
- static int
- recurse (volatile int n)
- {
- int sum = 0;
- return *recurse_1 (n, &sum);
- }
- int
- main ()
- {
- int result;
- #if HAVE_SETRLIMIT && defined RLIMIT_STACK
- /* Before starting the endless recursion, try to be friendly
- to the user's machine. On some Linux 2.2.x systems, there
- is no stack limit for user processes at all. We don't want
- to kill such systems. */
- struct rlimit rl;
- rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
- setrlimit (RLIMIT_STACK, &rl);
- #endif
+ sigemptyset (&act.sa_mask);
+ act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND | SA_SIGINFO;
+ act.sa_sigaction = segv_handler;
+ #if FAULT_YIELDS_SIGBUS
+ if (sigaction (SIGBUS, &act, 0) < 0)
+ return 2;
+ #endif
+ if (sigaction (SIGSEGV, &act, 0) < 0)
+ return 3;
+ return 0;
+ }
+ static volatile int *
+ recurse_1 (volatile int n, volatile int *p)
+ {
+ if (n >= 0)
+ *recurse_1 (n + 1, p) += n;
+ return p;
+ }
+ static int
+ recurse (volatile int n)
+ {
+ int sum = 0;
+ return *recurse_1 (n, &sum);
+ }
+ int
+ main ()
+ {
+ int result;
+ #if HAVE_SETRLIMIT && defined RLIMIT_STACK
+ /* Before starting the endless recursion, try to be friendly
+ to the user's machine. On some Linux 2.2.x systems, there
+ is no stack limit for user processes at all. We don't want
+ to kill such systems. */
+ struct rlimit rl;
+ rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
+ setrlimit (RLIMIT_STACK, &rl);
+ #endif
- result = c_stack_action ();
- if (result != 0)
- return result;
- return recurse (0);
- }
- ]])],
- [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])])
+ result = c_stack_action ();
+ if (result != 0)
+ return result;
+ return recurse (0);
+ }
+ ]])],
+ [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])
+ ;;
+ esac
+ ])
if test $ac_cv_sys_xsi_stack_overflow_heuristic = yes; then
AC_DEFINE([HAVE_XSI_STACK_OVERFLOW_HEURISTIC], [1],