int Mono_Unix_UnixSignal_uninstall (void* info) { signal_info* h; int r = -1; if (acquire_mutex (&signals_mutex) == -1) return -1; h = info; if (h == NULL || h < signals || h > &signals [NUM_SIGNALS]) errno = EINVAL; else { /* last UnixSignal -- we can unregister */ if (h->have_handler && count_handlers (h->signum) == 1) { mph_sighandler_t p = signal (h->signum, h->handler); if (p != SIG_ERR) r = 0; h->handler = NULL; h->have_handler = 0; } h->signum = 0; } release_mutex (&signals_mutex); return r; }
// A UnixSignal object is being Disposed int Mono_Unix_UnixSignal_uninstall (void* info) { #if defined(HAVE_SIGNAL) signal_info* h; int r = -1; if (acquire_mutex (&signals_mutex) == -1) return -1; h = info; if (h == NULL || h < signals || h > &signals [NUM_SIGNALS]) errno = EINVAL; else { /* last UnixSignal -- we can unregister */ int signum = mph_int_get (&h->signum); if (h->have_handler && count_handlers (signum) == 1) { mph_sighandler_t p = signal (signum, h->handler); if (p != SIG_ERR) r = 0; h->handler = NULL; h->have_handler = 0; } mph_int_set (&h->signum, 0); } release_mutex (&signals_mutex); return r; #else g_error ("signal() is not supported by this platform"); return 0; #endif }
int count_handlers( eventhandler **list ) { if (*list == NULL) { return 0; } else { return 1 + count_handlers( &( (*list)->next ) ); } }
void* Mono_Unix_UnixSignal_install (int sig) { int i; signal_info* h = NULL; int have_handler = 0; void* handler = NULL; if (acquire_mutex (&signals_mutex) == -1) return NULL; #if defined (SIGRTMIN) && defined (SIGRTMAX) /*The runtime uses some rt signals for itself so it's important to not override them.*/ if (sig >= SIGRTMIN && sig <= SIGRTMAX && count_handlers (sig) == 0) { struct sigaction sinfo; sigaction (sig, NULL, &sinfo); if (sinfo.sa_handler != SIG_DFL || (void*)sinfo.sa_sigaction != (void*)SIG_DFL) { pthread_mutex_unlock (&signals_mutex); errno = EADDRINUSE; return NULL; } } #endif /*defined (SIGRTMIN) && defined (SIGRTMAX)*/ for (i = 0; i < NUM_SIGNALS; ++i) { if (h == NULL && signals [i].signum == 0) { h = &signals [i]; h->handler = signal (sig, default_handler); if (h->handler == SIG_ERR) { h->handler = NULL; h = NULL; break; } else { h->have_handler = 1; } } if (!have_handler && signals [i].signum == sig && signals [i].handler != default_handler) { have_handler = 1; handler = signals [i].handler; } if (h && have_handler) break; } if (h && have_handler) { h->have_handler = 1; h->handler = handler; } if (h) { mph_int_set (&h->count, h->count, 0); mph_int_set (&h->signum, h->signum, sig); mph_int_set (&h->pipecnt, h->pipecnt, 0); } release_mutex (&signals_mutex); return h; }
// A UnixSignal object is being constructed void* Mono_Unix_UnixSignal_install (int sig) { #if defined(HAVE_SIGNAL) int i; signal_info* h = NULL; // signals[] slot to install to int have_handler = 0; // Candidates for signal_info handler fields void* handler = NULL; if (acquire_mutex (&signals_mutex) == -1) return NULL; #if defined (SIGRTMIN) && defined (SIGRTMAX) /*The runtime uses some rt signals for itself so it's important to not override them.*/ if (sig >= SIGRTMIN && sig <= SIGRTMAX && count_handlers (sig) == 0) { struct sigaction sinfo; sigaction (sig, NULL, &sinfo); if (sinfo.sa_handler != SIG_DFL || (void*)sinfo.sa_sigaction != (void*)SIG_DFL) { pthread_mutex_unlock (&signals_mutex); errno = EADDRINUSE; return NULL; // This is an rt signal with an existing handler. Bail out. } } #endif /*defined (SIGRTMIN) && defined (SIGRTMAX)*/ // Scan through signals list looking for (1) an unused spot (2) a usable value for handler for (i = 0; i < NUM_SIGNALS; ++i) { int just_installed = 0; // We're still looking for a signal_info spot, and this one is available: if (h == NULL && mph_int_get (&signals [i].signum) == 0) { h = &signals [i]; h->handler = signal (sig, default_handler); if (h->handler == SIG_ERR) { h->handler = NULL; h = NULL; break; } else { just_installed = 1; } } // Check if this slot has a "usable" (not installed by this file) handler-to-restore-later: // (On the first signal to be installed, signals [i] will be == h when this happens.) if (!have_handler && (just_installed || mph_int_get (&signals [i].signum) == sig) && signals [i].handler != default_handler) { have_handler = 1; handler = signals [i].handler; } if (h && have_handler) // We have everything we need break; } if (h) { // If we reached here without have_handler, this means that default_handler // was set as the signal handler before the first UnixSignal object was installed. g_assert (have_handler); // Overwrite the tenative handler we set a moment ago with a known-usable one h->handler = handler; h->have_handler = 1; mph_int_set (&h->count, 0); mph_int_set (&h->pipecnt, 0); mph_int_set (&h->signum, sig); } release_mutex (&signals_mutex); return h; #else g_error ("signal() is not supported by this platform"); return 0; #endif }