Date: Mon, 10 Mar 2003 22:50:40 +0100 From: Richard Nyberg <rnyberg@it.su.se> To: freebsd-stable@freebsd.org Subject: -pthread and test program Message-ID: <20030310215040.GA60926@murmeldjur.it.su.se>
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This program i from the lang/ocaml port. It is supposed to check
wether stack overflow is detectable or not.
The test is compiled in two different ways:
1) cc stackov.c
2) cc -pthread stackov.c
The first binary exits fast with a value of 0.
The second binary however, never exits. It just runs
forever eating CPU. Is this a bug in libc_r?
-Richard
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/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 2001 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License, with */
/* the special exception on linking described in file ../../LICENSE. */
/* */
/***********************************************************************/
/* $Id: stackov.c,v 1.3 2001/12/07 13:39:44 xleroy Exp $ */
#include <stdio.h>
#include <signal.h>
#include <sys/resource.h>
static char sig_alt_stack[SIGSTKSZ];
static char * system_stack_top;
#if defined(TARGET_i386) && defined(SYS_linux_elf)
static void segv_handler(int signo, struct sigcontext sc)
{
char * fault_addr = (char *) sc.cr2;
#else
static void segv_handler(int signo, siginfo_t * info, void * context)
{
char * fault_addr = (char *) info->si_addr;
#endif
struct rlimit limit;
if (getrlimit(RLIMIT_STACK, &limit) == 0 &&
((long) fault_addr & (sizeof(long) - 1)) == 0 &&
fault_addr < system_stack_top &&
fault_addr >= system_stack_top - limit.rlim_cur - 0x2000) {
_exit(0);
} else {
_exit(4);
}
}
void f(char * c);
void g(char * c) { char d[1024]; f(d); }
void f(char * c) { char d[1024]; g(d); }
int main(int argc, char ** argv)
{
struct sigaltstack stk;
struct sigaction act;
struct rlimit limit;
stk.ss_sp = sig_alt_stack;
stk.ss_size = SIGSTKSZ;
stk.ss_flags = 0;
#if defined(TARGET_i386) && defined(SYS_linux_elf)
act.sa_handler = (void (*)(int)) segv_handler;
act.sa_flags = SA_ONSTACK | SA_NODEFER;
#else
act.sa_sigaction = segv_handler;
act.sa_flags = SA_SIGINFO | SA_ONSTACK | SA_NODEFER;
#endif
sigemptyset(&act.sa_mask);
system_stack_top = (char *) &act;
limit.rlim_max = limit.rlim_cur = 0x20000;
if (sigaltstack(&stk, NULL) != 0) { perror("sigaltstack"); return 2; }
if (sigaction(SIGSEGV, &act, NULL) != 0) { perror("sigaction"); return 2; }
if (setrlimit(RLIMIT_STACK, &limit) != 0) { perror("setrlimit"); return 2; }
f(NULL);
return 2;
}
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