Commit 760f104f authored by simonmar's avatar simonmar

[project @ 2001-10-31 10:34:29 by simonmar]

Fix a problem when a Haskell process is suspended/resumed using shell
job control in Unix.  The shell tends to put stdin back into blocking
mode before resuming the process, so we have to catch SIGCONT and put
it back into O_NONBLOCK.

Also:

  - fix a bug in the scheduler: reverse the order of the check
    for pending signals and the call to awaitEvent to block on I/O.

  - do a style sweep in Signals.c
parent ab01dd37
/* -----------------------------------------------------------------------------
* $Id: RtsStartup.c,v 1.53 2001/09/04 18:29:21 ken Exp $
* $Id: RtsStartup.c,v 1.54 2001/10/31 10:34:29 simonmar Exp $
*
* (c) The GHC Team, 1998-2000
*
......@@ -177,7 +177,7 @@ startupHaskell(int argc, char *argv[], void (*init_root)(void))
/* Initialise the user signal handler set */
initUserSignals();
/* Set up handler to run on SIGINT, etc. */
init_default_handlers();
initDefaultHandlers();
#endif
#ifdef RTS_GTK_FRONTPANEL
......
/* ---------------------------------------------------------------------------
* $Id: Schedule.c,v 1.103 2001/10/27 22:05:48 sof Exp $
* $Id: Schedule.c,v 1.104 2001/10/31 10:34:29 simonmar Exp $
*
* (c) The GHC Team, 1998-2000
*
......@@ -529,6 +529,13 @@ schedule( void )
}
#endif /* SMP */
/* check for signals each time around the scheduler */
#ifndef mingw32_TARGET_OS
if (signals_pending()) {
startSignalHandlers();
}
#endif
/* Check whether any waiting threads need to be woken up. If the
* run queue is empty, and there are no other tasks running, we
* can wait indefinitely for something to happen.
......@@ -546,13 +553,6 @@ schedule( void )
/* we can be interrupted while waiting for I/O... */
if (interrupted) continue;
/* check for signals each time around the scheduler */
#ifndef mingw32_TARGET_OS
if (signals_pending()) {
start_signal_handlers();
}
#endif
/*
* Detect deadlock: when we have no threads to run, there are no
* threads waiting on I/O or sleeping, and all the other tasks are
......
/* -----------------------------------------------------------------------------
* $Id: Select.c,v 1.17 2001/08/14 13:40:09 sewardj Exp $
* $Id: Select.c,v 1.18 2001/10/31 10:34:29 simonmar Exp $
*
* (c) The GHC Team 1995-1999
*
......@@ -201,7 +201,7 @@ awaitEvent(rtsBool wait)
*/
if (signals_pending()) {
RELEASE_LOCK(&sched_mutex); /* ToDo: kill */
start_signal_handlers();
startSignalHandlers();
ACQUIRE_LOCK(&sched_mutex);
return; /* still hold the lock */
}
......
/* -----------------------------------------------------------------------------
* $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
*
......@@ -7,7 +7,7 @@
*
* ---------------------------------------------------------------------------*/
/* This is non=Posix compliant.
/* This is non-Posix-compliant.
#include "PosixSource.h"
*/
#include "Rts.h"
......@@ -38,39 +38,55 @@ StgPtr *next_pending_handler = pending_handler_buf;
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)
......@@ -105,24 +121,29 @@ 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;
......@@ -147,8 +168,8 @@ unblockUserSignals(void)
/* -----------------------------------------------------------------------------
Install a Haskell signal handler.
-------------------------------------------------------------------------- */
* Install a Haskell signal handler.
* -------------------------------------------------------------------------- */
StgInt
stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask)
......@@ -157,12 +178,13 @@ 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];
......@@ -181,7 +203,7 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask)
break;
case STG_SIG_HAN:
handlers[sig] = (I_)handler;
handlers[sig] = (StgInt)handler;
sigaddset(&userSignals, sig);
action.sa_handler = generic_handler;
break;
......@@ -200,24 +222,22 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask)
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();
......@@ -233,27 +253,26 @@ start_signal_handlers(void)
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
......@@ -262,28 +281,29 @@ static void
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.
*
......@@ -295,31 +315,40 @@ shutdown_handler(int sig STG_UNUSED)
* 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);
......
/* -----------------------------------------------------------------------------
* $Id: Signals.h,v 1.5 2000/02/22 12:09:24 simonmar Exp $
* $Id: Signals.h,v 1.6 2001/10/31 10:34:29 simonmar Exp $
*
* (c) The GHC Team, 1998-1999
*
......@@ -20,9 +20,8 @@ extern void unblockUserSignals(void);
/* sig_install declared in PrimOps.h */
extern void start_signal_handlers(void);
extern void init_default_handlers(void);
extern void startSignalHandlers(void);
extern void initDefaultHandlers(void);
#else
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment