(AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC): Limit stack size

to 1MB, so as not to render systems with no stack size limit (e.g.,
linux-2.2.x) unusable.  Suggestion and code from Bruno Haible.

diff --git a/m4/c-stack.m4 b/m4/c-stack.m4
index a58cde00917d68da2bf542da5188d6f2c32049e4..666a8ee06e2d7648f334942d92c62a403c5ba36f 100644 (file)
--- a/m4/c-stack.m4
+++ b/m4/c-stack.m4
@@ -22,6 +22,7 @@
 AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
   [# for STACK_DIRECTION
    AC_REQUIRE([AC_FUNC_ALLOCA])
+   AC_CHECK_FUNCS(setrlimit)
 
    AC_CACHE_CHECK([for working C stack overflow detection],
      ac_cv_sys_xsi_stack_overflow_heuristic,
@@ -30,6 +31,11 @@ AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
         #include <unistd.h>
         #include <signal.h>
         #include <ucontext.h>
+        #if HAVE_SETRLIMIT
+        # include <sys/types.h>
+        # include <sys/time.h>
+        # include <sys/resource.h>
+        #endif
 
         static union
         {
@@ -102,6 +108,16 @@ AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
         int
         main (void)
         {
+          #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
+
           c_stack_action ();
           return recurse ("\1");
         }