/* -----------------------------------------------------------------------------
- * $Id: Signals.c,v 1.21 2001/08/14 13:40:09 sewardj Exp $
+ * $Id: Signals.c,v 1.22 2001/10/31 10:34:29 simonmar Exp $
*
* (c) The GHC Team, 1998-1999
*
*
* ---------------------------------------------------------------------------*/
-/* This is non=Posix compliant.
+/* This is non-Posix-compliant.
#include "PosixSource.h"
*/
#include "Rts.h"
StgInt nocldstop = 0;
/* -----------------------------------------------------------------------------
- Allocate/resize the table of signal handlers.
- -------------------------------------------------------------------------- */
+ * Allocate/resize the table of signal handlers.
+ * -------------------------------------------------------------------------- */
static void
more_handlers(I_ sig)
{
- I_ i;
+ StgInt i;
if (sig < nHandlers)
- return;
+ return;
if (handlers == NULL)
- handlers = (I_ *) malloc((sig + 1) * sizeof(I_));
+ handlers = (StgInt *) malloc((sig + 1) * sizeof(StgInt));
else
- handlers = (I_ *) realloc(handlers, (sig + 1) * sizeof(I_));
+ handlers = (StgInt *) realloc(handlers, (sig + 1) * sizeof(StgInt));
if (handlers == NULL) {
- /* don't fflush(stdout); WORKAROUND bug in Linux glibc */
- barf("VM exhausted (in more_handlers)");
+ // don't fflush(stdout); WORKAROUND bug in Linux glibc
+ barf("VM exhausted (in more_handlers)");
}
for(i = nHandlers; i <= sig; i++)
- /* Fill in the new slots with default actions */
- handlers[i] = STG_SIG_DFL;
+ // Fill in the new slots with default actions
+ handlers[i] = STG_SIG_DFL;
nHandlers = sig + 1;
}
/* -----------------------------------------------------------------------------
- Low-level signal handler
+ * SIGCONT handler
+ *
+ * It seems that shells tend to put stdin back into blocking mode
+ * following a suspend/resume of the process. Here we arrange to put
+ * it back into non-blocking mode. We don't do anything to
+ * stdout/stderr because these handles don't get put into non-blocking
+ * mode at all - see the comments on stdout/stderr in PrelHandle.hsc.
+ * -------------------------------------------------------------------------- */
- Places the requested handler on a stack of pending handlers to be
- started up at the next context switch.
- -------------------------------------------------------------------------- */
+static void
+cont_handler(int sig STG_UNUSED)
+{
+ setNonBlockingFd(0);
+}
+
+/* -----------------------------------------------------------------------------
+ * Low-level signal handler
+ *
+ * Places the requested handler on a stack of pending handlers to be
+ * started up at the next context switch.
+ * -------------------------------------------------------------------------- */
static void
generic_handler(int sig)
circumstances, depending on the signal.
*/
- *next_pending_handler++ = deRefStablePtr(stgCast(StgStablePtr,handlers[sig]));
+ *next_pending_handler++ = deRefStablePtr((StgStablePtr)handlers[sig]);
- /* stack full? */
+ // stack full?
if (next_pending_handler == &pending_handler_buf[N_PENDING_HANDLERS]) {
- barf("too many pending signals");
+ barf("too many pending signals");
}
- /* re-establish the signal handler, and carry on */
+ // re-establish the signal handler, and carry on
sigemptyset(&signals);
sigaddset(&signals, sig);
sigprocmask(SIG_UNBLOCK, &signals, NULL);
+ // *always* do the SIGCONT handler, even if the user overrides it.
+ if (sig == SIGCONT) {
+ cont_handler(sig);
+ }
+
context_switch = 1;
}
/* -----------------------------------------------------------------------------
- Blocking/Unblocking of the user signals
- -------------------------------------------------------------------------- */
+ * Blocking/Unblocking of the user signals
+ * -------------------------------------------------------------------------- */
static sigset_t userSignals;
static sigset_t savedSignals;
/* -----------------------------------------------------------------------------
- Install a Haskell signal handler.
- -------------------------------------------------------------------------- */
+ * Install a Haskell signal handler.
+ * -------------------------------------------------------------------------- */
StgInt
stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask)
struct sigaction action;
StgInt previous_spi;
- /* Block the signal until we figure out what to do */
- /* Count on this to fail if the signal number is invalid */
- if(sig < 0 || sigemptyset(&signals) || sigaddset(&signals, sig) ||
- sigprocmask(SIG_BLOCK, &signals, NULL))
- return STG_SIG_ERR;
-
+ // Block the signal until we figure out what to do
+ // Count on this to fail if the signal number is invalid
+ if (sig < 0 || sigemptyset(&signals) ||
+ sigaddset(&signals, sig) || sigprocmask(SIG_BLOCK, &signals, NULL)) {
+ return STG_SIG_ERR;
+ }
+
more_handlers(sig);
previous_spi = handlers[sig];
break;
case STG_SIG_HAN:
- handlers[sig] = (I_)handler;
+ handlers[sig] = (StgInt)handler;
sigaddset(&userSignals, sig);
action.sa_handler = generic_handler;
break;
if (sigaction(sig, &action, NULL) ||
sigprocmask(SIG_UNBLOCK, &signals, NULL))
{
- /* need to return an error code, so avoid a stable pointer leak
- * by freeing the previous handler if there was one.
- */
- if (previous_spi >= 0) {
- freeStablePtr(stgCast(StgStablePtr,handlers[sig]));
- }
- return STG_SIG_ERR;
+ // need to return an error code, so avoid a stable pointer leak
+ // by freeing the previous handler if there was one.
+ if (previous_spi >= 0) {
+ freeStablePtr(stgCast(StgStablePtr,handlers[sig]));
+ }
+ return STG_SIG_ERR;
}
-
+
return previous_spi;
}
/* -----------------------------------------------------------------------------
- Creating new threads for the pending signal handlers.
- -------------------------------------------------------------------------- */
-
+ * Creating new threads for the pending signal handlers.
+ * -------------------------------------------------------------------------- */
void
-start_signal_handlers(void)
+startSignalHandlers(void)
{
blockUserSignals();
unblockUserSignals();
}
-#else /* PAR */
+#else // PAR
StgInt
stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask)
{
- /* don't fflush(stdout); WORKAROUND bug in Linux glibc */
- barf("no signal handling support in a parallel implementation");
+ // don't fflush(stdout); WORKAROUND bug in Linux glibc
+ barf("no signal handling support in a parallel implementation");
}
void
-start_signal_handlers(void)
+startSignalHandlers(void)
{
}
#endif
/* -----------------------------------------------------------------------------
- SIGINT handler.
-
- We like to shutdown nicely after receiving a SIGINT, write out the
- stats, write profiling info, close open files and flush buffers etc.
- -------------------------------------------------------------------------- */
-
+ * SIGINT handler.
+ *
+ * We like to shutdown nicely after receiving a SIGINT, write out the
+ * stats, write profiling info, close open files and flush buffers etc.
+ * -------------------------------------------------------------------------- */
#ifdef SMP
pthread_t startup_guy;
#endif
shutdown_handler(int sig STG_UNUSED)
{
#ifdef SMP
- /* if I'm a worker thread, send this signal to the guy who
- * originally called startupHaskell(). Since we're handling
- * the signal, it won't be a "send to all threads" type of signal
- * (according to the POSIX threads spec).
- */
- if (pthread_self() != startup_guy) {
- pthread_kill(startup_guy, sig);
- } else
+ // if I'm a worker thread, send this signal to the guy who
+ // originally called startupHaskell(). Since we're handling
+ // the signal, it won't be a "send to all threads" type of signal
+ // (according to the POSIX threads spec).
+ if (pthread_self() != startup_guy) {
+ pthread_kill(startup_guy, sig);
+ return;
+ }
#endif
- /* If we're already trying to interrupt the RTS, terminate with
- * extreme prejudice. So the first ^C tries to exit the program
- * cleanly, and the second one just kills it.
- */
- if (interrupted) {
- exit(EXIT_INTERRUPTED);
- } else {
- interruptStgRts();
- }
+ // If we're already trying to interrupt the RTS, terminate with
+ // extreme prejudice. So the first ^C tries to exit the program
+ // cleanly, and the second one just kills it.
+ if (interrupted) {
+ exit(EXIT_INTERRUPTED);
+ } else {
+ interruptStgRts();
+ }
}
-/*
+/* -----------------------------------------------------------------------------
+ * Install default signal handlers.
+ *
* The RTS installs a default signal handler for catching
* SIGINT, so that we can perform an orderly shutdown.
*
* by ignoring it. Apparently IEEE requires floating-point
* exceptions to be ignored by default, but alpha-dec-osf3
* doesn't seem to do so.
- */
+ * -------------------------------------------------------------------------- */
void
-init_default_handlers()
+initDefaultHandlers()
{
struct sigaction action,oact;
#ifdef SMP
startup_guy = pthread_self();
#endif
+
+ // install the SIGINT handler
action.sa_handler = shutdown_handler;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
if (sigaction(SIGINT, &action, &oact) != 0) {
- /* Oh well, at least we tried. */
- prog_belch("failed to install SIGINT handler");
+ prog_belch("warning: failed to install SIGINT handler");
}
- siginterrupt(SIGINT, 1);
+ siginterrupt(SIGINT, 1); // isn't this the default? --SDM
+
+ // install the SIGCONT handler
+ action.sa_handler = cont_handler;
+ sigemptyset(&action.sa_mask);
+ action.sa_flags = 0;
+ if (sigaction(SIGCONT, &action, &oact) != 0) {
+ prog_belch("warning: failed to install SIGCONT handler");
+ }
+ // install the SIGFPE handler
action.sa_handler = SIG_IGN;
sigemptyset(&action.sa_mask);
action.sa_flags = 0;
if (sigaction(SIGFPE, &action, &oact) != 0) {
- /* Oh well, at least we tried. */
- prog_belch("failed to install SIGFPE handler");
+ prog_belch("warning: failed to install SIGFPE handler");
}
#ifdef alpha_TARGET_ARCH
ieee_set_fp_control(0);
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