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ocaml/byterun/signals.c

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/**************************************************************************/
/* */
/* OCaml */
/* */
/* Xavier Leroy and Damien Doligez, INRIA Rocquencourt */
/* */
/* Copyright 1996 Institut National de Recherche en Informatique et */
/* en Automatique. */
/* */
/* All rights reserved. This file is distributed under the terms of */
/* the GNU Lesser General Public License version 2.1, with the */
/* special exception on linking described in the file LICENSE. */
/* */
/**************************************************************************/
/* Signal handling, code common to the bytecode and native systems */
#include <signal.h>
#include <errno.h>
#include "caml/alloc.h"
#include "caml/callback.h"
#include "caml/config.h"
#include "caml/fail.h"
#include "caml/memory.h"
#include "caml/misc.h"
#include "caml/mlvalues.h"
#include "caml/roots.h"
#include "caml/signals.h"
#include "caml/signals_machdep.h"
#include "caml/sys.h"
#ifndef NSIG
#define NSIG 64
#endif
/* The set of pending signals (received but not yet processed) */
CAMLexport intnat volatile caml_signals_are_pending = 0;
CAMLexport intnat volatile caml_pending_signals[NSIG];
/* Execute all pending signals */
void caml_process_pending_signals(void)
{
int i;
if (caml_signals_are_pending) {
caml_signals_are_pending = 0;
for (i = 0; i < NSIG; i++) {
if (caml_pending_signals[i]) {
caml_pending_signals[i] = 0;
caml_execute_signal(i, 0);
}
}
}
}
/* Record the delivery of a signal, and arrange for it to be processed
as soon as possible:
- in bytecode: via caml_something_to_do, processed in caml_process_event
- in native-code: by playing with the allocation limit, processed
in caml_garbage_collection
*/
void caml_record_signal(int signal_number)
{
caml_pending_signals[signal_number] = 1;
caml_signals_are_pending = 1;
#ifndef NATIVE_CODE
caml_something_to_do = 1;
#else
caml_young_limit = caml_young_alloc_end;
#endif
}
/* Management of blocking sections. */
static intnat volatile caml_async_signal_mode = 0;
static void caml_enter_blocking_section_default(void)
{
Assert (caml_async_signal_mode == 0);
caml_async_signal_mode = 1;
}
static void caml_leave_blocking_section_default(void)
{
Assert (caml_async_signal_mode == 1);
caml_async_signal_mode = 0;
}
static int caml_try_leave_blocking_section_default(void)
{
intnat res;
Read_and_clear(res, caml_async_signal_mode);
return res;
}
CAMLexport void (*caml_enter_blocking_section_hook)(void) =
caml_enter_blocking_section_default;
CAMLexport void (*caml_leave_blocking_section_hook)(void) =
caml_leave_blocking_section_default;
CAMLexport int (*caml_try_leave_blocking_section_hook)(void) =
caml_try_leave_blocking_section_default;
CAMLexport void caml_enter_blocking_section(void)
{
while (1){
/* Process all pending signals now */
caml_process_pending_signals();
caml_enter_blocking_section_hook ();
/* Check again for pending signals.
If none, done; otherwise, try again */
if (! caml_signals_are_pending) break;
caml_leave_blocking_section_hook ();
}
}
CAMLexport void caml_leave_blocking_section(void)
{
int saved_errno;
/* Save the value of errno (PR#5982). */
saved_errno = errno;
caml_leave_blocking_section_hook ();
caml_process_pending_signals();
errno = saved_errno;
}
/* Execute a signal handler immediately */
static value caml_signal_handlers = 0;
void caml_execute_signal(int signal_number, int in_signal_handler)
{
value res;
#ifdef POSIX_SIGNALS
sigset_t sigs;
/* Block the signal before executing the handler, and record in sigs
the original signal mask */
sigemptyset(&sigs);
sigaddset(&sigs, signal_number);
sigprocmask(SIG_BLOCK, &sigs, &sigs);
#endif
res = caml_callback_exn(
Field(caml_signal_handlers, signal_number),
Val_int(caml_rev_convert_signal_number(signal_number)));
#ifdef POSIX_SIGNALS
if (! in_signal_handler) {
/* Restore the original signal mask */
sigprocmask(SIG_SETMASK, &sigs, NULL);
} else if (Is_exception_result(res)) {
/* Restore the original signal mask and unblock the signal itself */
sigdelset(&sigs, signal_number);
sigprocmask(SIG_SETMASK, &sigs, NULL);
}
#endif
if (Is_exception_result(res)) caml_raise(Extract_exception(res));
}
/* Arrange for a garbage collection to be performed as soon as possible */
int volatile caml_requested_major_slice = 0;
int volatile caml_requested_minor_gc = 0;
void caml_request_major_slice (void)
{
caml_requested_major_slice = 1;
#ifndef NATIVE_CODE
caml_something_to_do = 1;
#else
caml_young_limit = caml_young_alloc_end;
/* This is only moderately effective on ports that cache [caml_young_limit]
in a register, since [caml_modify] is called directly, not through
[caml_c_call], so it may take a while before the register is reloaded
from [caml_young_limit]. */
#endif
}
void caml_request_minor_gc (void)
{
caml_requested_minor_gc = 1;
#ifndef NATIVE_CODE
caml_something_to_do = 1;
#else
caml_young_limit = caml_young_alloc_end;
/* Same remark as above in [caml_request_major_slice]. */
#endif
}
/* OS-independent numbering of signals */
#ifndef SIGABRT
#define SIGABRT -1
#endif
#ifndef SIGALRM
#define SIGALRM -1
#endif
#ifndef SIGFPE
#define SIGFPE -1
#endif
#ifndef SIGHUP
#define SIGHUP -1
#endif
#ifndef SIGILL
#define SIGILL -1
#endif
#ifndef SIGINT
#define SIGINT -1
#endif
#ifndef SIGKILL
#define SIGKILL -1
#endif
#ifndef SIGPIPE
#define SIGPIPE -1
#endif
#ifndef SIGQUIT
#define SIGQUIT -1
#endif
#ifndef SIGSEGV
#define SIGSEGV -1
#endif
#ifndef SIGTERM
#define SIGTERM -1
#endif
#ifndef SIGUSR1
#define SIGUSR1 -1
#endif
#ifndef SIGUSR2
#define SIGUSR2 -1
#endif
#ifndef SIGCHLD
#define SIGCHLD -1
#endif
#ifndef SIGCONT
#define SIGCONT -1
#endif
#ifndef SIGSTOP
#define SIGSTOP -1
#endif
#ifndef SIGTSTP
#define SIGTSTP -1
#endif
#ifndef SIGTTIN
#define SIGTTIN -1
#endif
#ifndef SIGTTOU
#define SIGTTOU -1
#endif
#ifndef SIGVTALRM
#define SIGVTALRM -1
#endif
#ifndef SIGPROF
#define SIGPROF -1
#endif
#ifndef SIGBUS
#define SIGBUS -1
#endif
#ifndef SIGPOLL
#define SIGPOLL -1
#endif
#ifndef SIGSYS
#define SIGSYS -1
#endif
#ifndef SIGTRAP
#define SIGTRAP -1
#endif
#ifndef SIGURG
#define SIGURG -1
#endif
#ifndef SIGXCPU
#define SIGXCPU -1
#endif
#ifndef SIGXFSZ
#define SIGXFSZ -1
#endif
static int posix_signals[] = {
SIGABRT, SIGALRM, SIGFPE, SIGHUP, SIGILL, SIGINT, SIGKILL, SIGPIPE,
SIGQUIT, SIGSEGV, SIGTERM, SIGUSR1, SIGUSR2, SIGCHLD, SIGCONT,
SIGSTOP, SIGTSTP, SIGTTIN, SIGTTOU, SIGVTALRM, SIGPROF, SIGBUS,
SIGPOLL, SIGSYS, SIGTRAP, SIGURG, SIGXCPU, SIGXFSZ
};
CAMLexport int caml_convert_signal_number(int signo)
{
if (signo < 0 && signo >= -(sizeof(posix_signals) / sizeof(int)))
return posix_signals[-signo-1];
else
return signo;
}
CAMLexport int caml_rev_convert_signal_number(int signo)
{
int i;
for (i = 0; i < sizeof(posix_signals) / sizeof(int); i++)
if (signo == posix_signals[i]) return -i - 1;
return signo;
}
/* Installation of a signal handler (as per [Sys.signal]) */
CAMLprim value caml_install_signal_handler(value signal_number, value action)
{
CAMLparam2 (signal_number, action);
CAMLlocal1 (res);
int sig, act, oldact;
sig = caml_convert_signal_number(Int_val(signal_number));
if (sig < 0 || sig >= NSIG)
caml_invalid_argument("Sys.signal: unavailable signal");
switch(action) {
case Val_int(0): /* Signal_default */
act = 0;
break;
case Val_int(1): /* Signal_ignore */
act = 1;
break;
default: /* Signal_handle */
act = 2;
break;
}
oldact = caml_set_signal_action(sig, act);
switch (oldact) {
case 0: /* was Signal_default */
res = Val_int(0);
break;
case 1: /* was Signal_ignore */
res = Val_int(1);
break;
case 2: /* was Signal_handle */
res = caml_alloc_small (1, 0);
Field(res, 0) = Field(caml_signal_handlers, sig);
break;
default: /* error in caml_set_signal_action */
caml_sys_error(NO_ARG);
}
if (Is_block(action)) {
if (caml_signal_handlers == 0) {
caml_signal_handlers = caml_alloc(NSIG, 0);
caml_register_global_root(&caml_signal_handlers);
}
caml_modify(&Field(caml_signal_handlers, sig), Field(action, 0));
}
caml_process_pending_signals();
CAMLreturn (res);
}
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