/* Copyright (C) 1995,1996,1997,1998,1999,2000,2001, 2002, 2004, 2006, * 2007, 2008, 2009, 2011, 2013, 2014, 2017 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License * as published by the Free Software Foundation; either version 3 of * the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * 02110-1301 USA */ #ifdef HAVE_CONFIG_H # include #endif #include /* for mingw */ #include #include #include #ifdef HAVE_PROCESS_H #include /* for mingw */ #endif #include #ifdef HAVE_SYS_TIME_H #include #endif #include #include "libguile/_scm.h" #include "libguile/async.h" #include "libguile/eval.h" #include "libguile/vectors.h" #include "libguile/threads.h" #include "libguile/validate.h" #include "libguile/scmsigs.h" /* SIGRETTYPE is the type that signal handlers return. See */ #ifdef RETSIGTYPE # define SIGRETTYPE RETSIGTYPE #else # ifdef STDC_HEADERS # define SIGRETTYPE void # else # define SIGRETTYPE int # endif #endif /* take_signal is installed as the C signal handler whenever a Scheme handler is set. When a signal arrives, take_signal will write a byte into the 'signal pipe'. The 'signal delivery thread' will read this pipe and queue the appropriate asyncs. When Guile is built without threads, the signal handler will install the async directly. */ /* Scheme vectors with information about a signal. signal_handlers contains the handler procedure or #f, signal_handler_asyncs contains the thunk to be marked as an async when the signal arrives (or the cell with the thunk in a singlethreaded Guile), and signal_handler_threads points to the thread that a signal should be delivered to. */ static scm_i_pthread_mutex_t signal_handler_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER; static SCM *signal_handlers; static SCM signal_handler_asyncs; static SCM signal_handler_threads; /* The signal delivery thread. */ scm_i_thread *scm_i_signal_delivery_thread = NULL; /* The mutex held when launching the signal delivery thread. */ static scm_i_pthread_mutex_t signal_delivery_thread_mutex = SCM_I_PTHREAD_MUTEX_INITIALIZER; /* saves the original C handlers, when a new handler is installed. set to SIG_ERR if the original handler is installed. */ #ifdef HAVE_SIGACTION static struct sigaction orig_handlers[NSIG]; #else static SIGRETTYPE (*orig_handlers[NSIG])(int); #endif static SCM close_1 (SCM proc, SCM arg) { /* Eval in the root module so that `lambda' has its usual meaning. */ return scm_eval (scm_list_3 (scm_sym_lambda, SCM_EOL, scm_list_2 (proc, arg)), scm_the_root_module ()); } #if SCM_USE_PTHREAD_THREADS /* On mingw there's no notion of inter-process signals, only a raise() within the process itself which apparently invokes the registered handler immediately. Not sure how well the following code will cope in this case. It builds but it may not offer quite the same scheme-level semantics as on a proper system. If you're relying on much in the way of signal handling on mingw you probably lose anyway. */ static int signal_pipe[2]; static SIGRETTYPE take_signal (int signum) { int old_errno = errno; char sigbyte = signum; full_write (signal_pipe[1], &sigbyte, 1); #ifndef HAVE_SIGACTION signal (signum, take_signal); #endif errno = old_errno; } struct signal_pipe_data { char sigbyte; ssize_t n; int err; }; static void* read_signal_pipe_data (void * data) { struct signal_pipe_data *sdata = data; sdata->n = read (signal_pipe[0], &sdata->sigbyte, 1); sdata->err = errno; return NULL; } static SCM signal_delivery_thread (void *data) { int sig; #if HAVE_PTHREAD_SIGMASK /* not on mingw, see notes above */ sigset_t all_sigs; sigfillset (&all_sigs); /* On libgc 7.1 and earlier, GC_do_blocking doesn't actually do anything. So in that case, libgc will want to suspend the signal delivery thread, so we need to allow it to do so by unmasking the suspend signal. */ sigdelset (&all_sigs, GC_get_suspend_signal ()); scm_i_pthread_sigmask (SIG_SETMASK, &all_sigs, NULL); #endif while (1) { struct signal_pipe_data sigdata; /* This tick gives any pending asyncs a chance to run before we block indefinitely waiting for a signal to arrive. For example it can happen that the garbage collector is triggered while marking the signal handler for future execution. Due to the way the after-gc-hook is designed, without a call to scm_async_tick, the after-gc-hook will not be triggered. */ scm_async_tick (); scm_without_guile (read_signal_pipe_data, &sigdata); sig = sigdata.sigbyte; if (sigdata.n == 1 && sig >= 0 && sig < NSIG) { SCM h, t; h = SCM_SIMPLE_VECTOR_REF (signal_handler_asyncs, sig); t = SCM_SIMPLE_VECTOR_REF (signal_handler_threads, sig); if (scm_is_true (h)) scm_system_async_mark_for_thread (h, t); } else if (sigdata.n == 0) break; /* the signal pipe was closed. */ else if (sigdata.n < 0 && sigdata.err != EINTR) perror ("error in signal delivery thread"); } return SCM_UNSPECIFIED; /* not reached unless all other threads exited */ } static void start_signal_delivery_thread (void) { SCM signal_thread; scm_i_pthread_mutex_lock (&signal_delivery_thread_mutex); if (pipe2 (signal_pipe, O_CLOEXEC) != 0) scm_syserror (NULL); signal_thread = scm_spawn_thread (signal_delivery_thread, NULL, scm_handle_by_message, "signal delivery thread"); scm_i_signal_delivery_thread = SCM_I_THREAD_DATA (signal_thread); scm_i_pthread_mutex_unlock (&signal_delivery_thread_mutex); } void scm_i_ensure_signal_delivery_thread () { static scm_i_pthread_once_t once = SCM_I_PTHREAD_ONCE_INIT; scm_i_pthread_once (&once, start_signal_delivery_thread); } #else /* !SCM_USE_PTHREAD_THREADS */ static SIGRETTYPE take_signal (int signum) { SCM cell = SCM_SIMPLE_VECTOR_REF (signal_handler_asyncs, signum); scm_i_thread *t = SCM_I_CURRENT_THREAD; if (scm_is_false (SCM_CDR (cell))) { SCM_SETCDR (cell, t->pending_asyncs); t->pending_asyncs = cell; } #ifndef HAVE_SIGACTION signal (signum, take_signal); #endif } void scm_i_ensure_signal_delivery_thread () { return; } #endif /* !SCM_USE_PTHREAD_THREADS */ static void install_handler (int signum, SCM thread, SCM handler) { if (scm_is_false (handler)) { SCM_SIMPLE_VECTOR_SET (*signal_handlers, signum, SCM_BOOL_F); SCM_SIMPLE_VECTOR_SET (signal_handler_asyncs, signum, SCM_BOOL_F); } else { SCM async = close_1 (handler, scm_from_int (signum)); #if !SCM_USE_PTHREAD_THREADS async = scm_cons (async, SCM_BOOL_F); #endif SCM_SIMPLE_VECTOR_SET (*signal_handlers, signum, handler); SCM_SIMPLE_VECTOR_SET (signal_handler_asyncs, signum, async); } SCM_SIMPLE_VECTOR_SET (signal_handler_threads, signum, thread); } SCM scm_sigaction (SCM signum, SCM handler, SCM flags) { return scm_sigaction_for_thread (signum, handler, flags, SCM_UNDEFINED); } /* user interface for installation of signal handlers. */ SCM_DEFINE (scm_sigaction_for_thread, "sigaction", 1, 3, 0, (SCM signum, SCM handler, SCM flags, SCM thread), "Install or report the signal handler for a specified signal.\n\n" "@var{signum} is the signal number, which can be specified using the value\n" "of variables such as @code{SIGINT}.\n\n" "If @var{handler} is omitted, @code{sigaction} returns a pair: the\n" "CAR is the current\n" "signal hander, which will be either an integer with the value @code{SIG_DFL}\n" "(default action) or @code{SIG_IGN} (ignore), or the Scheme procedure which\n" "handles the signal, or @code{#f} if a non-Scheme procedure handles the\n" "signal. The CDR contains the current @code{sigaction} flags for the handler.\n\n" "If @var{handler} is provided, it is installed as the new handler for\n" "@var{signum}. @var{handler} can be a Scheme procedure taking one\n" "argument, or the value of @code{SIG_DFL} (default action) or\n" "@code{SIG_IGN} (ignore), or @code{#f} to restore whatever signal handler\n" "was installed before @code{sigaction} was first used. When\n" "a scheme procedure has been specified, that procedure will run\n" "in the given @var{thread}. When no thread has been given, the\n" "thread that made this call to @code{sigaction} is used.\n" "Flags can optionally be specified for the new handler.\n" "The return value is a pair with information about the\n" "old handler as described above.\n\n" "This interface does not provide access to the \"signal blocking\"\n" "facility. Maybe this is not needed, since the thread support may\n" "provide solutions to the problem of consistent access to data\n" "structures.") #define FUNC_NAME s_scm_sigaction_for_thread { int csig; #ifdef HAVE_SIGACTION struct sigaction action; struct sigaction old_action; #else SIGRETTYPE (* chandler) (int) = SIG_DFL; SIGRETTYPE (* old_chandler) (int); #endif int query_only = 0; int save_handler = 0; SCM old_handler; csig = scm_to_signed_integer (signum, 0, NSIG-1); #if defined(HAVE_SIGACTION) action.sa_flags = 0; if (!SCM_UNBNDP (flags)) action.sa_flags |= scm_to_int (flags); sigemptyset (&action.sa_mask); #endif if (SCM_UNBNDP (thread)) thread = scm_current_thread (); else SCM_VALIDATE_THREAD (4, thread); scm_i_ensure_signal_delivery_thread (); scm_dynwind_begin (0); scm_i_dynwind_pthread_mutex_lock (&signal_handler_lock); scm_dynwind_block_asyncs (); old_handler = SCM_SIMPLE_VECTOR_REF (*signal_handlers, csig); if (SCM_UNBNDP (handler)) query_only = 1; else if (scm_is_integer (handler)) { long handler_int = scm_to_long (handler); if (handler_int == (long) SIG_DFL || handler_int == (long) SIG_IGN) { #ifdef HAVE_SIGACTION action.sa_handler = (SIGRETTYPE (*) (int)) handler_int; #else chandler = (SIGRETTYPE (*) (int)) handler_int; #endif install_handler (csig, SCM_BOOL_F, SCM_BOOL_F); } else { SCM_OUT_OF_RANGE (2, handler); } } else if (scm_is_false (handler)) { /* restore the default handler. */ #ifdef HAVE_SIGACTION if (orig_handlers[csig].sa_handler == SIG_ERR) query_only = 1; else { action = orig_handlers[csig]; orig_handlers[csig].sa_handler = SIG_ERR; install_handler (csig, SCM_BOOL_F, SCM_BOOL_F); } #else if (orig_handlers[csig] == SIG_ERR) query_only = 1; else { chandler = orig_handlers[csig]; orig_handlers[csig] = SIG_ERR; install_handler (csig, SCM_BOOL_F, SCM_BOOL_F); } #endif } else { SCM_VALIDATE_PROC (2, handler); #ifdef HAVE_SIGACTION action.sa_handler = take_signal; if (orig_handlers[csig].sa_handler == SIG_ERR) save_handler = 1; #else chandler = take_signal; if (orig_handlers[csig] == SIG_ERR) save_handler = 1; #endif install_handler (csig, thread, handler); } /* XXX - Silently ignore setting handlers for `program error signals' because they can't currently be handled by Scheme code. */ switch (csig) { /* This list of program error signals is from the GNU Libc Reference Manual */ case SIGFPE: case SIGILL: case SIGSEGV: #ifdef SIGBUS case SIGBUS: #endif case SIGABRT: #if defined(SIGIOT) && (SIGIOT != SIGABRT) case SIGIOT: #endif #ifdef SIGTRAP case SIGTRAP: #endif #ifdef SIGEMT case SIGEMT: #endif #ifdef SIGSYS case SIGSYS: #endif query_only = 1; } #ifdef HAVE_SIGACTION if (query_only) { if (sigaction (csig, 0, &old_action) == -1) SCM_SYSERROR; } else { if (sigaction (csig, &action , &old_action) == -1) SCM_SYSERROR; if (save_handler) orig_handlers[csig] = old_action; } if (old_action.sa_handler == SIG_DFL || old_action.sa_handler == SIG_IGN) old_handler = scm_from_long ((long) old_action.sa_handler); scm_dynwind_end (); return scm_cons (old_handler, scm_from_int (old_action.sa_flags)); #else if (query_only) { if ((old_chandler = signal (csig, SIG_IGN)) == SIG_ERR) SCM_SYSERROR; if (signal (csig, old_chandler) == SIG_ERR) SCM_SYSERROR; } else { if ((old_chandler = signal (csig, chandler)) == SIG_ERR) SCM_SYSERROR; if (save_handler) orig_handlers[csig] = old_chandler; } if (old_chandler == SIG_DFL || old_chandler == SIG_IGN) old_handler = scm_from_long ((long) old_chandler); scm_dynwind_end (); return scm_cons (old_handler, scm_from_int (0)); #endif } #undef FUNC_NAME SCM_DEFINE (scm_restore_signals, "restore-signals", 0, 0, 0, (void), "Return all signal handlers to the values they had before any call to\n" "@code{sigaction} was made. The return value is unspecified.") #define FUNC_NAME s_scm_restore_signals { int i; for (i = 0; i < NSIG; i++) { #ifdef HAVE_SIGACTION if (orig_handlers[i].sa_handler != SIG_ERR) { if (sigaction (i, &orig_handlers[i], NULL) == -1) SCM_SYSERROR; orig_handlers[i].sa_handler = SIG_ERR; SCM_SIMPLE_VECTOR_SET (*signal_handlers, i, SCM_BOOL_F); } #else if (orig_handlers[i] != SIG_ERR) { if (signal (i, orig_handlers[i]) == SIG_ERR) SCM_SYSERROR; orig_handlers[i] = SIG_ERR; SCM_SIMPLE_VECTOR_SET (*signal_handlers, i, SCM_BOOL_F); } #endif } return SCM_UNSPECIFIED; } #undef FUNC_NAME #if HAVE_DECL_ALARM SCM_DEFINE (scm_alarm, "alarm", 1, 0, 0, (SCM i), "Set a timer to raise a @code{SIGALRM} signal after the specified\n" "number of seconds (an integer). It's advisable to install a signal\n" "handler for\n" "@code{SIGALRM} beforehand, since the default action is to terminate\n" "the process.\n\n" "The return value indicates the time remaining for the previous alarm,\n" "if any. The new value replaces the previous alarm. If there was\n" "no previous alarm, the return value is zero.") #define FUNC_NAME s_scm_alarm { return scm_from_uint (alarm (scm_to_uint (i))); } #undef FUNC_NAME #endif /* HAVE_ALARM */ static void pack_tv (struct timeval *tv, SCM seconds, SCM microseconds) { tv->tv_sec = scm_to_long (seconds); tv->tv_usec = scm_to_long (microseconds); /* Allow usec to be outside the range [0, 999999). */ tv->tv_sec += tv->tv_usec / (1000 * 1000); tv->tv_usec %= 1000 * 1000; } static SCM unpack_tv (const struct timeval *tv) { return scm_cons (scm_from_long (tv->tv_sec), scm_from_long (tv->tv_usec)); } #ifdef HAVE_SETITIMER SCM_DEFINE (scm_setitimer, "setitimer", 5, 0, 0, (SCM which_timer, SCM interval_seconds, SCM interval_microseconds, SCM value_seconds, SCM value_microseconds), "Set the timer specified by @var{which_timer} according to the given\n" "@var{interval_seconds}, @var{interval_microseconds},\n" "@var{value_seconds}, and @var{value_microseconds} values.\n" "\n" "Return information about the timer's previous setting." "\n" "Errors are handled as described in the guile info pages under ``POSIX\n" "Interface Conventions''.\n" "\n" "The timers available are: @code{ITIMER_REAL}, @code{ITIMER_VIRTUAL},\n" "and @code{ITIMER_PROF}.\n" "\n" "The return value will be a list of two cons pairs representing the\n" "current state of the given timer. The first pair is the seconds and\n" "microseconds of the timer @code{it_interval}, and the second pair is\n" "the seconds and microseconds of the timer @code{it_value}." "\n" "@code{ITIMER_PROF} or @code{ITIMER_VIRTUAL} are not supported on\n" "some platforms and will always error. @code{(provided? 'ITIMER_PROF)}\n" "and @code{(provided? 'ITIMER_VIRTUAL)} report whether those timers\n" "are supported.\n") #define FUNC_NAME s_scm_setitimer { int rv; int c_which_timer; struct itimerval new_timer; struct itimerval old_timer; c_which_timer = SCM_NUM2INT(1, which_timer); pack_tv (&new_timer.it_interval, interval_seconds, interval_microseconds); pack_tv (&new_timer.it_value, value_seconds, value_microseconds); SCM_SYSCALL(rv = setitimer(c_which_timer, &new_timer, &old_timer)); if(rv != 0) SCM_SYSERROR; return scm_list_2 (unpack_tv (&old_timer.it_interval), unpack_tv (&old_timer.it_value)); } #undef FUNC_NAME #endif /* HAVE_SETITIMER */ #ifdef HAVE_GETITIMER SCM_DEFINE (scm_getitimer, "getitimer", 1, 0, 0, (SCM which_timer), "Return information about the timer specified by @var{which_timer}" "\n" "Errors are handled as described in the guile info pages under ``POSIX\n" "Interface Conventions''.\n" "\n" "The timers available are: @code{ITIMER_REAL}, @code{ITIMER_VIRTUAL},\n" "and @code{ITIMER_PROF}.\n" "\n" "The return value will be a list of two cons pairs representing the\n" "current state of the given timer. The first pair is the seconds and\n" "microseconds of the timer @code{it_interval}, and the second pair is\n" "the seconds and microseconds of the timer @code{it_value}." "\n" "@code{ITIMER_PROF} or @code{ITIMER_VIRTUAL} are not supported on\n" "some platforms and will always error. @code{(provided? 'ITIMER_PROF)}\n" "and @code{(provided? 'ITIMER_VIRTUAL)} report whether those timers\n" "are supported.\n") #define FUNC_NAME s_scm_getitimer { int rv; int c_which_timer; struct itimerval old_timer; c_which_timer = SCM_NUM2INT(1, which_timer); SCM_SYSCALL(rv = getitimer(c_which_timer, &old_timer)); if(rv != 0) SCM_SYSERROR; return scm_list_2 (scm_cons (scm_from_long (old_timer.it_interval.tv_sec), scm_from_long (old_timer.it_interval.tv_usec)), scm_cons (scm_from_long (old_timer.it_value.tv_sec), scm_from_long (old_timer.it_value.tv_usec))); } #undef FUNC_NAME #endif /* HAVE_GETITIMER */ #ifdef HAVE_PAUSE SCM_DEFINE (scm_pause, "pause", 0, 0, 0, (), "Pause the current process (thread?) until a signal arrives whose\n" "action is to either terminate the current process or invoke a\n" "handler procedure. The return value is unspecified.") #define FUNC_NAME s_scm_pause { pause (); return SCM_UNSPECIFIED; } #undef FUNC_NAME #endif SCM_DEFINE (scm_sleep, "sleep", 1, 0, 0, (SCM i), "Wait for the given number of seconds (an integer) or until a signal\n" "arrives. The return value is zero if the time elapses or the number\n" "of seconds remaining otherwise.\n" "\n" "See also @code{usleep}.") #define FUNC_NAME s_scm_sleep { return scm_from_uint (scm_std_sleep (scm_to_uint (i))); } #undef FUNC_NAME SCM_DEFINE (scm_usleep, "usleep", 1, 0, 0, (SCM i), "Wait the given period @var{usecs} microseconds (an integer).\n" "If a signal arrives the wait stops and the return value is the\n" "time remaining, in microseconds. If the period elapses with no\n" "signal the return is zero.\n" "\n" "On most systems the process scheduler is not microsecond accurate and\n" "the actual period slept by @code{usleep} may be rounded to a system\n" "clock tick boundary. Traditionally such ticks were 10 milliseconds\n" "apart, and that interval is often still used.\n" "\n" "See also @code{sleep}.") #define FUNC_NAME s_scm_usleep { return scm_from_ulong (scm_std_usleep (scm_to_ulong (i))); } #undef FUNC_NAME SCM_DEFINE (scm_raise, "raise", 1, 0, 0, (SCM sig), "Sends a specified signal @var{sig} to the current process, where\n" "@var{sig} is as described for the kill procedure.") #define FUNC_NAME s_scm_raise { if (raise (scm_to_int (sig)) != 0) SCM_SYSERROR; return SCM_UNSPECIFIED; } #undef FUNC_NAME void scm_i_close_signal_pipe() { /* SIGNAL_DELIVERY_THREAD_MUTEX is only locked while the signal delivery thread is being launched. The thread that calls this function is already holding the thread admin mutex, so if the delivery thread hasn't been launched at this point, it never will be before shutdown. */ scm_i_pthread_mutex_lock (&signal_delivery_thread_mutex); #if SCM_USE_PTHREAD_THREADS if (scm_i_signal_delivery_thread != NULL) close (signal_pipe[1]); #endif scm_i_pthread_mutex_unlock (&signal_delivery_thread_mutex); } void scm_init_scmsigs () { int i; signal_handlers = SCM_VARIABLE_LOC (scm_c_define ("signal-handlers", scm_c_make_vector (NSIG, SCM_BOOL_F))); signal_handler_asyncs = scm_c_make_vector (NSIG, SCM_BOOL_F); signal_handler_threads = scm_c_make_vector (NSIG, SCM_BOOL_F); for (i = 0; i < NSIG; i++) { #ifdef HAVE_SIGACTION orig_handlers[i].sa_handler = SIG_ERR; #else orig_handlers[i] = SIG_ERR; #endif } scm_c_define ("NSIG", scm_from_long (NSIG)); scm_c_define ("SIG_IGN", scm_from_long ((long) SIG_IGN)); scm_c_define ("SIG_DFL", scm_from_long ((long) SIG_DFL)); #ifdef SA_NOCLDSTOP scm_c_define ("SA_NOCLDSTOP", scm_from_long (SA_NOCLDSTOP)); #endif #ifdef SA_RESTART scm_c_define ("SA_RESTART", scm_from_long (SA_RESTART)); #endif #if defined(HAVE_SETITIMER) || defined(HAVE_GETITIMER) /* Stuff needed by setitimer and getitimer. */ scm_c_define ("ITIMER_REAL", scm_from_int (ITIMER_REAL)); scm_c_define ("ITIMER_VIRTUAL", scm_from_int (ITIMER_VIRTUAL)); scm_c_define ("ITIMER_PROF", scm_from_int (ITIMER_PROF)); #ifdef HAVE_USABLE_GETITIMER_PROF scm_add_feature ("ITIMER_PROF"); #endif #ifdef HAVE_USABLE_GETITIMER_VIRTUAL scm_add_feature ("ITIMER_VIRTUAL"); #endif #endif /* defined(HAVE_SETITIMER) || defined(HAVE_GETITIMER) */ #include "libguile/scmsigs.x" } /* Local Variables: c-file-style: "gnu" End: */