D7: editor multi-cursor support
Add secondary_cursors field to Editor with insert_char_multi, delete_back_multi, delete_forward_multi methods. Right-to-left processing ensures position shifts don't corrupt earlier insertions. 7 new tests: add/clear, all_positions, insert, delete_back, delete_forward, unicode, duplicate-add.
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@@ -0,0 +1,359 @@
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# Check prerequisites for compiling lib/c-stack.c.
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# Copyright (C) 2002-2004, 2008-2017 Free Software Foundation, Inc.
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# This file is free software; the Free Software Foundation
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# gives unlimited permission to copy and/or distribute it,
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# with or without modifications, as long as this notice is preserved.
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# Written by Paul Eggert.
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# serial 15
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AC_DEFUN([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC],
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[
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AC_REQUIRE([AC_CANONICAL_HOST])
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AC_CHECK_FUNCS_ONCE([setrlimit])
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AC_CHECK_HEADERS_ONCE([ucontext.h])
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dnl List of signals that are sent when an invalid virtual memory address
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dnl is accessed, or when the stack overflows.
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dnl Either { SIGSEGV } or { SIGSEGV, SIGBUS }.
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case "$host_os" in
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sunos4* | freebsd* | dragonfly* | openbsd* | mirbsd* | netbsd* | kfreebsd* | knetbsd*) # BSD systems
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FAULT_YIELDS_SIGBUS=1 ;;
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hpux*) # HP-UX
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FAULT_YIELDS_SIGBUS=1 ;;
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macos* | darwin*) # Mac OS X
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FAULT_YIELDS_SIGBUS=1 ;;
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gnu*) # Hurd
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FAULT_YIELDS_SIGBUS=1 ;;
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*)
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FAULT_YIELDS_SIGBUS=0 ;;
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esac
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AC_DEFINE_UNQUOTED([FAULT_YIELDS_SIGBUS], [$FAULT_YIELDS_SIGBUS],
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[Define to 1 if an invalid memory address access may yield a SIGBUS.])
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AC_CACHE_CHECK([for working C stack overflow detection],
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[ac_cv_sys_stack_overflow_works],
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[AC_RUN_IFELSE([AC_LANG_SOURCE(
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[[
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#include <unistd.h>
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#include <signal.h>
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#if HAVE_SETRLIMIT
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# include <sys/types.h>
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# include <sys/time.h>
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# include <sys/resource.h>
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#endif
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#ifndef SIGSTKSZ
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# define SIGSTKSZ 16384
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#endif
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static union
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{
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char buffer[2 * SIGSTKSZ];
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long double ld;
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long u;
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void *p;
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} alternate_signal_stack;
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static void
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segv_handler (int signo)
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{
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_exit (0);
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}
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static int
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c_stack_action ()
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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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/* Use the midpoint to avoid Irix sigaltstack bug. */
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st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
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st.ss_size = SIGSTKSZ;
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r = sigaltstack (&st, 0);
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if (r != 0)
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return 1;
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sigemptyset (&act.sa_mask);
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act.sa_flags = SA_NODEFER | SA_ONSTACK | SA_RESETHAND;
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act.sa_handler = segv_handler;
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#if FAULT_YIELDS_SIGBUS
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if (sigaction (SIGBUS, &act, 0) < 0)
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return 2;
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#endif
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if (sigaction (SIGSEGV, &act, 0) < 0)
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return 3;
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return 0;
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}
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static volatile int *
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recurse_1 (volatile int n, volatile int *p)
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{
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if (n >= 0)
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*recurse_1 (n + 1, p) += n;
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return p;
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}
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static int
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recurse (volatile int n)
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{
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int sum = 0;
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return *recurse_1 (n, &sum);
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}
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int
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main ()
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{
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int result;
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#if HAVE_SETRLIMIT && defined RLIMIT_STACK
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/* Before starting the endless recursion, try to be friendly
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to the user's machine. On some Linux 2.2.x systems, there
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is no stack limit for user processes at all. We don't want
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to kill such systems. */
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struct rlimit rl;
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rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
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setrlimit (RLIMIT_STACK, &rl);
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#endif
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result = c_stack_action ();
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if (result != 0)
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return result;
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return recurse (0);
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}
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]])],
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[ac_cv_sys_stack_overflow_works=yes],
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[ac_cv_sys_stack_overflow_works=no],
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[ac_cv_sys_stack_overflow_works=cross-compiling])])
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if test $ac_cv_sys_stack_overflow_works = yes; then
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AC_DEFINE([HAVE_STACK_OVERFLOW_HANDLING], [1],
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[Define to 1 if extending the stack slightly past the limit causes
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a SIGSEGV which can be handled on an alternate stack established
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with sigaltstack.])
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dnl The ss_sp field of a stack_t is, according to POSIX, the lowest address
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dnl of the memory block designated as an alternate stack. But IRIX 5.3
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dnl interprets it as the highest address!
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AC_CACHE_CHECK([for correct stack_t interpretation],
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[gl_cv_sigaltstack_low_base], [
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AC_RUN_IFELSE([
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AC_LANG_SOURCE([[
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#include <stdlib.h>
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#include <signal.h>
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#if HAVE_SYS_SIGNAL_H
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# include <sys/signal.h>
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#endif
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#ifndef SIGSTKSZ
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# define SIGSTKSZ 16384
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#endif
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volatile char *stack_lower_bound;
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volatile char *stack_upper_bound;
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static void check_stack_location (volatile char *addr)
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{
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if (addr >= stack_lower_bound && addr <= stack_upper_bound)
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exit (0);
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else
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exit (1);
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}
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static void stackoverflow_handler (int sig)
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{
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char dummy;
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check_stack_location (&dummy);
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}
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int main ()
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{
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char mystack[2 * SIGSTKSZ];
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stack_t altstack;
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struct sigaction action;
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/* Install the alternate stack. */
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altstack.ss_sp = mystack + SIGSTKSZ;
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altstack.ss_size = SIGSTKSZ;
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stack_lower_bound = (char *) altstack.ss_sp;
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stack_upper_bound = (char *) altstack.ss_sp + altstack.ss_size - 1;
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altstack.ss_flags = 0; /* no SS_DISABLE */
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if (sigaltstack (&altstack, NULL) < 0)
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exit (2);
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/* Install the SIGSEGV handler. */
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sigemptyset (&action.sa_mask);
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action.sa_handler = &stackoverflow_handler;
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action.sa_flags = SA_ONSTACK;
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if (sigaction (SIGSEGV, &action, (struct sigaction *) NULL) < 0)
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exit(3);
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/* Provoke a SIGSEGV. */
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raise (SIGSEGV);
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exit (4);
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}]])],
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[gl_cv_sigaltstack_low_base=yes],
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[gl_cv_sigaltstack_low_base=no],
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[gl_cv_sigaltstack_low_base=cross-compiling])])
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if test "$gl_cv_sigaltstack_low_base" = no; then
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AC_DEFINE([SIGALTSTACK_SS_REVERSED], [1],
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[Define if sigaltstack() interprets the stack_t.ss_sp field
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incorrectly, as the highest address of the alternate stack range
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rather than as the lowest address.])
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fi
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AC_CACHE_CHECK([for precise C stack overflow detection],
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ac_cv_sys_xsi_stack_overflow_heuristic,
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[AC_RUN_IFELSE([AC_LANG_SOURCE(
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[[
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#include <unistd.h>
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#include <signal.h>
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#if HAVE_UCONTEXT_H
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# include <ucontext.h>
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#endif
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#if HAVE_SETRLIMIT
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# include <sys/types.h>
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# include <sys/time.h>
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# include <sys/resource.h>
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#endif
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#ifndef SIGSTKSZ
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# define SIGSTKSZ 16384
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#endif
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static union
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{
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char buffer[2 * SIGSTKSZ];
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long double ld;
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long 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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/* For XSI heuristics to work, we need uc_stack to describe
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the interrupted stack (as on Solaris), and not the
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currently executing stack (as on Linux). */
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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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_exit (4);
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}
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_exit (5);
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}
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static int
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c_stack_action ()
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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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/* Use the midpoint to avoid Irix sigaltstack bug. */
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st.ss_sp = alternate_signal_stack.buffer + SIGSTKSZ;
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st.ss_size = SIGSTKSZ;
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r = sigaltstack (&st, 0);
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if (r != 0)
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return 1;
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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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#if FAULT_YIELDS_SIGBUS
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if (sigaction (SIGBUS, &act, 0) < 0)
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return 2;
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#endif
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if (sigaction (SIGSEGV, &act, 0) < 0)
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return 3;
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return 0;
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}
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static volatile int *
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recurse_1 (volatile int n, volatile int *p)
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{
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if (n >= 0)
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*recurse_1 (n + 1, p) += n;
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return p;
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}
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static int
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recurse (volatile int n)
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{
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int sum = 0;
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return *recurse_1 (n, &sum);
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}
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int
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main ()
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{
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int result;
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#if HAVE_SETRLIMIT && defined RLIMIT_STACK
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/* Before starting the endless recursion, try to be friendly
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to the user's machine. On some Linux 2.2.x systems, there
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is no stack limit for user processes at all. We don't want
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to kill such systems. */
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struct rlimit rl;
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rl.rlim_cur = rl.rlim_max = 0x100000; /* 1 MB */
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setrlimit (RLIMIT_STACK, &rl);
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#endif
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result = c_stack_action ();
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if (result != 0)
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return result;
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return recurse (0);
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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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fi])
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AC_DEFUN([gl_PREREQ_C_STACK],
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[AC_REQUIRE([AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC])
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AC_REQUIRE([gl_LIBSIGSEGV])
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# for STACK_DIRECTION
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AC_REQUIRE([AC_FUNC_ALLOCA])
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AC_CHECK_FUNCS_ONCE([sigaltstack])
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AC_CHECK_DECLS([sigaltstack], , , [[#include <signal.h>]])
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AC_CHECK_HEADERS_ONCE([unistd.h ucontext.h])
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AC_CHECK_TYPES([stack_t], , , [#include <signal.h>])
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dnl c-stack does not need -lsigsegv if the system has XSI heuristics.
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if test "$gl_cv_lib_sigsegv" = yes \
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&& test $"ac_cv_sys_xsi_stack_overflow_heuristic" != yes ; then
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AC_SUBST([LIBCSTACK], [$LIBSIGSEGV])
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AC_SUBST([LTLIBCSTACK], [$LTLIBSIGSEGV])
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fi
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])
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AC_DEFUN([gl_C_STACK],
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[
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dnl Prerequisites of lib/c-stack.c.
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gl_PREREQ_C_STACK
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])
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