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/* Longjump/Setjump wrapper
Copyright (C) 2002 - 2015 Tristan Gingold.
GHDL 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.
GHDL 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 GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.
As a special exception, if other files instantiate generics from this
unit, or you link this unit with other files to produce an executable,
this unit does not by itself cause the resulting executable to be
covered by the GNU General Public License. This exception does not
however invalidate any other reasons why the executable file might be
covered by the GNU Public License.
*/
#define _GNU_SOURCE
#include <stddef.h>
#include <signal.h>
#include <fcntl.h>
#if defined (__linux__) || defined (__APPLE__)
#define HAVE_BACKTRACE 1
#include <sys/ucontext.h>
#endif
#ifdef HAVE_BACKTRACE
#include <execinfo.h>
#endif
#include "grt_itf.h"
/* There is a simple setjmp/longjmp mechanism used to report failures.
We have the choice between 3 mechanisms:
* USE_BUITLIN_SJLJ: gcc builtin setjmp/longjmp, very fast but gcc specific.
* USE__SETJMP: _setjmp/_longjmp
* USE_SETJMP: setjmp/longjmp, slower because signals mask is saved/restored.
*/
#if defined (__GNUC__) && !defined (__clang__)
# define USE_BUILTIN_SJLJ
#else
# define USE__SETJMP
#endif
#ifdef USE_BUILTIN_SJLJ
typedef void *JMP_BUF[5];
static int sjlj_val;
# define SETJMP(BUF) (__builtin_setjmp (BUF), sjlj_val)
# define LONGJMP(BUF, VAL) \
do { sjlj_val = (VAL); __builtin_longjmp (BUF, 1); } while (0)
#else
# include <setjmp.h>
typedef jmp_buf JMP_BUF;
# ifdef USE__SETJMP
# define SETJMP _setjmp
# define LONGJMP _longjmp
# elif defined (USE_SETJMP)
# define SETJMP setjmp
# define LONGJMP longjmp
# else
# error "SETJMP/LONGJMP not configued"
# endif
#endif
static int run_env_en;
static JMP_BUF run_env;
#ifdef __APPLE__
#define NEED_SIGFPE_HANDLER
#define NEED_SIGBUS_HANDLER
#endif
static struct sigaction prev_sigfpe_act;
#ifdef NEED_SIGFPE_HANDLER
static struct sigaction prev_sigsegv_act;
#endif
#ifdef NEED_SIGBUS_HANDLER
static struct sigaction prev_sigbus_act;
#endif
static void
get_bt_from_ucontext (void *uctxt, struct backtrace_addrs *bt)
{
void *pc = NULL;
int i;
#ifdef HAVE_BACKTRACE
bt->size = backtrace (bt->addrs, sizeof (bt->addrs) / sizeof (void *));
bt->skip = 0;
#else
bt->size = 0;
return;
#endif
#if defined (__linux__) && defined (__x86_64__)
ucontext *u = (ucontext *)uctxt;
pc = (void *)u->uc_mcontext.gregs[REG_RIP];
#endif
#if defined (__APPLE__) && defined (__i386__)
ucontext_t *u = (ucontext_t *)uctxt;
pc = (void *)u->uc_mcontext->__ss.__eip;
bt->skip = 3; /* This frame + sighandler + trampoline + marker - pc. */
bt->addrs[3] = pc;
#endif
}
/* Handler for SIGFPE signal.
It is also raised in case of overflow (i386 linux). */
static void
grt_overflow_handler (int signo, siginfo_t *info, void *ptr)
{
struct backtrace_addrs bt;
get_bt_from_ucontext (ptr, &bt);
grt_overflow_error (&bt);
}
/* Posix handler for overflow. This is used only by mcode. */
static void
grt_sigsegv_handler (int signo, siginfo_t *info, void *ptr)
{
struct backtrace_addrs bt;
get_bt_from_ucontext (ptr, &bt);
#if defined (__linux__) && defined (__i386__)
if (signo == SIGSEGV)
{
ucontext_t *uctxt = (ucontext_t *)ptr;
/* Linux generates a SIGSEGV (!) for an overflow exception. */
if (uctxt->uc_mcontext.gregs[REG_TRAPNO] == 4)
grt_overflow_error (&bt);
}
#endif
/* We loose. */
grt_null_access_error (&bt);
}
static void
grt_signal_setup (void)
{
{
struct sigaction sigsegv_act;
sigsegv_act.sa_sigaction = &grt_sigsegv_handler;
sigemptyset (&sigsegv_act.sa_mask);
sigsegv_act.sa_flags = SA_SIGINFO;
#ifdef SA_ONESHOT
sigsegv_act.sa_flags |= SA_ONESHOT;
#elif defined (SA_RESETHAND)
sigsegv_act.sa_flags |= SA_RESETHAND;
#endif
/* We don't care about the return status.
If the handler is not installed, then some feature are lost. */
sigaction (SIGSEGV, &sigsegv_act, &prev_sigsegv_act);
#ifdef NEED_SIGBUS_HANDLER
sigaction (SIGBUS, &sigsegv_act, &prev_sigbus_act);
#endif
}
#ifdef NEED_SIGFPE_HANDLER
{
struct sigaction sig_ovf_act;
sig_ovf_act.sa_sigaction = &grt_overflow_handler;
sigemptyset (&sig_ovf_act.sa_mask);
sig_ovf_act.sa_flags = SA_SIGINFO;
sigaction (SIGFPE, &sig_ovf_act, &prev_sigfpe_act);
}
#endif
}
static void
grt_signal_restore (void)
{
sigaction (SIGSEGV, &prev_sigsegv_act, NULL);
#ifdef NEED_SIGBUS_HANDLER
sigaction (SIGBUS, &prev_sigbus_act, NULL);
#endif
#ifdef NEED_SIGFPE_HANDLER
sigaction (SIGFPE, &prev_sigfpe_act, NULL);
#endif
}
void
__ghdl_maybe_return_via_longjump (int val)
{
if (run_env_en)
LONGJMP (run_env, val);
}
int
__ghdl_run_through_longjump (int (*func)(void))
{
int res;
run_env_en = 1;
grt_signal_setup ();
res = SETJMP (run_env);
if (res == 0)
res = (*func)();
grt_signal_restore ();
run_env_en = 0;
return res;
}
void
grt_save_backtrace (struct backtrace_addrs *bt, int skip)
{
#ifdef HAVE_BACKTRACE
bt->size = backtrace (bt->addrs, sizeof (bt->addrs) / sizeof (void *));
bt->skip = skip + 1;
#else
bt->size = 0;
#endif
}
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