X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Frts%2FSignals.c;h=425d90a77a7a787c003b51e6e26b859999fa9b30;hb=e0b21a6c8434d1815db5ae0d336de590a04b31fc;hp=0685a2b2f6c57c7016832a6742ce7253af966aba;hpb=fbdb63665bef739a56e080670c78bda57b24af78;p=ghc-hetmet.git diff --git a/ghc/rts/Signals.c b/ghc/rts/Signals.c index 0685a2b..425d90a 100644 --- a/ghc/rts/Signals.c +++ b/ghc/rts/Signals.c @@ -1,5 +1,4 @@ /* ----------------------------------------------------------------------------- - * $Id: Signals.c,v 1.27 2002/09/03 14:07:03 simonmar Exp $ * * (c) The GHC Team, 1998-1999 * @@ -16,10 +15,13 @@ #include "Signals.h" #include "RtsUtils.h" #include "RtsFlags.h" -#include "StablePriv.h" -#ifdef alpha_TARGET_ARCH -# include +#ifdef alpha_HOST_ARCH +# if defined(linux_HOST_OS) +# include +# else +# include +# endif #endif #ifdef HAVE_UNISTD_H @@ -32,9 +34,17 @@ #include -#ifndef mingw32_TARGET_OS +/* This curious flag is provided for the benefit of the Haskell binding + * to POSIX.1 to control whether or not to include SA_NOCLDSTOP when + * installing a SIGCHLD handler. + */ +StgInt nocldstop = 0; -#ifndef PAR +/* ----------------------------------------------------------------------------- + * The table of signal handlers + * -------------------------------------------------------------------------- */ + +#if defined(RTS_USER_SIGNALS) /* SUP: The type of handlers is a little bit, well, doubtful... */ static StgInt *handlers = NULL; /* Dynamically grown array of signal handlers */ @@ -42,13 +52,6 @@ static StgInt nHandlers = 0; /* Size of handlers array */ static nat n_haskell_handlers = 0; -#define N_PENDING_HANDLERS 16 - -StgPtr pending_handler_buf[N_PENDING_HANDLERS]; -StgPtr *next_pending_handler = pending_handler_buf; - -StgInt nocldstop = 0; - /* ----------------------------------------------------------------------------- * Allocate/resize the table of signal handlers. * -------------------------------------------------------------------------- */ @@ -62,14 +65,10 @@ more_handlers(I_ sig) return; if (handlers == NULL) - handlers = (StgInt *) malloc((sig + 1) * sizeof(StgInt)); + handlers = (StgInt *)stgMallocBytes((sig + 1) * sizeof(StgInt), "more_handlers"); else - handlers = (StgInt *) realloc(handlers, (sig + 1) * sizeof(StgInt)); + handlers = (StgInt *)stgReallocBytes(handlers, (sig + 1) * sizeof(StgInt), "more_handlers"); - if (handlers == NULL) { - // 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; @@ -78,6 +77,53 @@ more_handlers(I_ sig) } /* ----------------------------------------------------------------------------- + * Pending Handlers + * + * The mechanism for starting handlers differs between the threaded + * (RTS_SUPPORTS_THREADS) and non-threaded versions of the RTS. + * + * When the RTS is single-threaded, we just write the pending signal + * handlers into a buffer, and start a thread for each one in the + * scheduler loop. + * + * When RTS_SUPPORTS_THREADS, the problem is that signals might be + * delivered to multiple threads, so we would need to synchronise + * access to pending_handler_buf somehow. Using thread + * synchronisation from a signal handler isn't possible in general + * (some OSs support it, eg. MacOS X, but not all). So instead: + * + * - the signal handler writes the signal number into the pipe + * managed by the IO manager thread (see GHC.Conc). + * - the IO manager picks up the signal number and calls + * startSignalHandler() to start the thread. + * + * This also has the nice property that we don't need to arrange to + * wake up a worker task to start the signal handler: the IO manager + * wakes up when we write into the pipe. + * + * -------------------------------------------------------------------------- */ + +// Here's the pipe into which we will send our signals +static int io_manager_pipe = -1; + +void +setIOManagerPipe (int fd) +{ + // only called when RTS_SUPPORTS_THREADS, but unconditionally + // compiled here because GHC.Conc depends on it. + io_manager_pipe = fd; +} + +#if !defined(RTS_SUPPORTS_THREADS) + +#define N_PENDING_HANDLERS 16 + +StgPtr pending_handler_buf[N_PENDING_HANDLERS]; +StgPtr *next_pending_handler = pending_handler_buf; + +#endif /* RTS_SUPPORTS_THREADS */ + +/* ----------------------------------------------------------------------------- * SIGCONT handler * * It seems that shells tend to put stdin back into blocking mode @@ -105,6 +151,21 @@ generic_handler(int sig) { sigset_t signals; +#if defined(RTS_SUPPORTS_THREADS) + + if (io_manager_pipe != -1) + { + // Write the signal number into the pipe as a single byte. We + // hope that signals fit into a byte... + StgWord8 csig = (StgWord8)sig; + write(io_manager_pipe, &csig, 1); + } + // If the IO manager hasn't told us what the FD of the write end + // of its pipe is, there's not much we can do here, so just ignore + // the signal.. + +#else /* not RTS_SUPPORTS_THREADS */ + /* Can't call allocate from here. Probably can't call malloc either. However, we have to schedule a new thread somehow. @@ -137,9 +198,12 @@ generic_handler(int sig) // stack full? if (next_pending_handler == &pending_handler_buf[N_PENDING_HANDLERS]) { - barf("too many pending signals"); + errorBelch("too many pending signals"); + stg_exit(EXIT_FAILURE); } +#endif /* RTS_SUPPORTS_THREADS */ + // re-establish the signal handler, and carry on sigemptyset(&signals); sigaddset(&signals, sig); @@ -169,7 +233,7 @@ initUserSignals(void) void blockUserSignals(void) { - sigprocmask(SIG_SETMASK, &userSignals, &savedSignals); + sigprocmask(SIG_BLOCK, &userSignals, &savedSignals); } void @@ -184,6 +248,7 @@ anyUserHandlers(void) return n_haskell_handlers != 0; } +#if !defined(RTS_SUPPORTS_THREADS) void awaitUserSignals(void) { @@ -191,13 +256,14 @@ awaitUserSignals(void) pause(); } } +#endif /* ----------------------------------------------------------------------------- * Install a Haskell signal handler. * -------------------------------------------------------------------------- */ -StgInt -stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, void *mask) +int +stg_sig_install(int sig, int spi, StgStablePtr *handler, void *mask) { sigset_t signals, osignals; struct sigaction action; @@ -214,6 +280,8 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, void *mask) previous_spi = handlers[sig]; + action.sa_flags = 0; + switch(spi) { case STG_SIG_IGN: handlers[sig] = STG_SIG_IGN; @@ -228,9 +296,13 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, void *mask) break; case STG_SIG_HAN: - handlers[sig] = (StgInt)handler; + case STG_SIG_RST: + handlers[sig] = (StgInt)*handler; sigaddset(&userSignals, sig); action.sa_handler = generic_handler; + if (spi == STG_SIG_RST) { + action.sa_flags = SA_RESETHAND; + } n_haskell_handlers++; break; @@ -243,7 +315,7 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, void *mask) else sigemptyset(&action.sa_mask); - action.sa_flags = sig == SIGCHLD && nocldstop ? SA_NOCLDSTOP : 0; + action.sa_flags |= sig == SIGCHLD && nocldstop ? SA_NOCLDSTOP : 0; if (sigaction(sig, &action, NULL) || sigprocmask(SIG_SETMASK, &osignals, NULL)) @@ -256,16 +328,40 @@ stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, void *mask) } return STG_SIG_ERR; } - - return previous_spi; + + if (previous_spi == STG_SIG_DFL || previous_spi == STG_SIG_IGN + || previous_spi == STG_SIG_ERR) { + return previous_spi; + } else { + *handler = (StgStablePtr)previous_spi; + return STG_SIG_HAN; + } } /* ----------------------------------------------------------------------------- - * Creating new threads for the pending signal handlers. + * Creating new threads for signal handlers. * -------------------------------------------------------------------------- */ + +void +startSignalHandler(int sig) // called by the IO manager, see GHC.Conc +{ +#if defined(RTS_SUPPORTS_THREADS) + // ToDo: fix race window between the time at which the signal is + // delivered and the deRefStablePtr() call here. There's no way + // to safely uninstall a signal handler. + scheduleThread( + createIOThread(RtsFlags.GcFlags.initialStkSize, + (StgClosure *)deRefStablePtr((StgStablePtr)handlers[sig])) + ); +#else + (void)sig; /* keep gcc -Wall happy */ +#endif +} + void startSignalHandlers(void) { +#if !defined(RTS_SUPPORTS_THREADS) blockUserSignals(); while (next_pending_handler != pending_handler_buf) { @@ -278,22 +374,51 @@ startSignalHandlers(void) } unblockUserSignals(); +#endif } -#else // PAR -StgInt -stg_sig_install(StgInt sig, StgInt spi, StgStablePtr handler, sigset_t *mask) +/* ---------------------------------------------------------------------------- + * Mark signal handlers during GC. + * + * We do this rather than trying to start all the signal handlers + * prior to GC, because that requires extra heap for the new threads. + * Signals must be blocked (see blockUserSignals() above) during GC to + * avoid race conditions. + * -------------------------------------------------------------------------- */ + +#if !defined(RTS_SUPPORTS_THREADS) +void +markSignalHandlers (evac_fn evac) { - // don't fflush(stdout); WORKAROUND bug in Linux glibc - barf("no signal handling support in a parallel implementation"); -} + StgPtr *p; + p = next_pending_handler; + while (p != pending_handler_buf) { + p--; + evac((StgClosure **)p); + } +} +#else void -startSignalHandlers(void) +markSignalHandlers (evac_fn evac STG_UNUSED) +{ +} +#endif + +#else /* !RTS_USER_SIGNALS */ +StgInt +stg_sig_install(StgInt sig STG_UNUSED, + StgInt spi STG_UNUSED, + StgStablePtr* handler STG_UNUSED, + void* mask STG_UNUSED) { + //barf("User signals not supported"); + return STG_SIG_DFL; } + #endif +#if defined(RTS_USER_SIGNALS) /* ----------------------------------------------------------------------------- * SIGINT handler. * @@ -322,7 +447,7 @@ shutdown_handler(int sig STG_UNUSED) // extreme prejudice. So the first ^C tries to exit the program // cleanly, and the second one just kills it. if (interrupted) { - exit(EXIT_INTERRUPTED); + stg_exit(EXIT_INTERRUPTED); } else { interruptStgRts(); } @@ -357,10 +482,10 @@ initDefaultHandlers() sigemptyset(&action.sa_mask); action.sa_flags = 0; if (sigaction(SIGINT, &action, &oact) != 0) { - prog_belch("warning: failed to install SIGINT handler"); + errorBelch("warning: failed to install SIGINT handler"); } -#ifndef cygwin32_TARGET_OS +#if defined(HAVE_SIGINTERRUPT) siginterrupt(SIGINT, 1); // isn't this the default? --SDM #endif @@ -369,7 +494,7 @@ initDefaultHandlers() sigemptyset(&action.sa_mask); action.sa_flags = 0; if (sigaction(SIGCONT, &action, &oact) != 0) { - prog_belch("warning: failed to install SIGCONT handler"); + errorBelch("warning: failed to install SIGCONT handler"); } // install the SIGFPE handler @@ -387,13 +512,13 @@ initDefaultHandlers() sigemptyset(&action.sa_mask); action.sa_flags = 0; if (sigaction(SIGFPE, &action, &oact) != 0) { - prog_belch("warning: failed to install SIGFPE handler"); + errorBelch("warning: failed to install SIGFPE handler"); } #endif -#ifdef alpha_TARGET_ARCH +#ifdef alpha_HOST_ARCH ieee_set_fp_control(0); #endif } -#endif /*! mingw32_TARGET_OS */ +#endif /* RTS_USER_SIGNALS */