*/
#include <signal.h>
-#include "time_user.h"
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdarg.h>
+#include <string.h>
+#include <sys/mman.h>
+#include "user_util.h"
+#include "user.h"
+#include "signal_kern.h"
+#include "sysdep/sigcontext.h"
+#include "sysdep/barrier.h"
+#include "sigcontext.h"
#include "mode.h"
-#include "sysdep/signal.h"
+#include "os.h"
-void sig_handler(ARCH_SIGHDLR_PARAM)
+/* These are the asynchronous signals. SIGVTALRM and SIGARLM are handled
+ * together under SIGVTALRM_BIT. SIGPROF is excluded because we want to
+ * be able to profile all of UML, not just the non-critical sections. If
+ * profiling is not thread-safe, then that is not my problem. We can disable
+ * profiling when SMP is enabled in that case.
+ */
+#define SIGIO_BIT 0
+#define SIGIO_MASK (1 << SIGIO_BIT)
+
+#define SIGVTALRM_BIT 1
+#define SIGVTALRM_MASK (1 << SIGVTALRM_BIT)
+
+#define SIGALRM_BIT 2
+#define SIGALRM_MASK (1 << SIGALRM_BIT)
+
+/* These are used by both the signal handlers and
+ * block/unblock_signals. I don't want modifications cached in a
+ * register - they must go straight to memory.
+ */
+static volatile int signals_enabled = 1;
+static volatile int pending = 0;
+
+void sig_handler(int sig, struct sigcontext *sc)
{
- struct sigcontext *sc;
+ int enabled;
+
+ enabled = signals_enabled;
+ if(!enabled && (sig == SIGIO)){
+ pending |= SIGIO_MASK;
+ return;
+ }
+
+ block_signals();
- ARCH_GET_SIGCONTEXT(sc, sig);
CHOOSE_MODE_PROC(sig_handler_common_tt, sig_handler_common_skas,
sig, sc);
-}
-extern int timer_irq_inited;
+ set_signals(enabled);
+}
-void alarm_handler(ARCH_SIGHDLR_PARAM)
+static void real_alarm_handler(int sig, struct sigcontext *sc)
{
- struct sigcontext *sc;
-
- ARCH_GET_SIGCONTEXT(sc, sig);
- if(!timer_irq_inited) return;
-
if(sig == SIGALRM)
switch_timers(0);
if(sig == SIGALRM)
switch_timers(1);
+
}
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only. This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-file-style: "linux"
- * End:
- */
+void alarm_handler(int sig, struct sigcontext *sc)
+{
+ int enabled;
+
+ enabled = signals_enabled;
+ if(!signals_enabled){
+ if(sig == SIGVTALRM)
+ pending |= SIGVTALRM_MASK;
+ else pending |= SIGALRM_MASK;
+
+ return;
+ }
+
+ block_signals();
+
+ real_alarm_handler(sig, sc);
+ set_signals(enabled);
+}
+
+void set_sigstack(void *sig_stack, int size)
+{
+ stack_t stack = ((stack_t) { .ss_flags = 0,
+ .ss_sp = (__ptr_t) sig_stack,
+ .ss_size = size - sizeof(void *) });
+
+ if(sigaltstack(&stack, NULL) != 0)
+ panic("enabling signal stack failed, errno = %d\n", errno);
+}
+
+void remove_sigstack(void)
+{
+ stack_t stack = ((stack_t) { .ss_flags = SS_DISABLE,
+ .ss_sp = NULL,
+ .ss_size = 0 });
+
+ if(sigaltstack(&stack, NULL) != 0)
+ panic("disabling signal stack failed, errno = %d\n", errno);
+}
+
+void (*handlers[_NSIG])(int sig, struct sigcontext *sc);
+
+extern void hard_handler(int sig);
+
+void set_handler(int sig, void (*handler)(int), int flags, ...)
+{
+ struct sigaction action;
+ va_list ap;
+ sigset_t sig_mask;
+ int mask;
+
+ handlers[sig] = (void (*)(int, struct sigcontext *)) handler;
+ action.sa_handler = hard_handler;
+
+ sigemptyset(&action.sa_mask);
+
+ va_start(ap, flags);
+ while((mask = va_arg(ap, int)) != -1)
+ sigaddset(&action.sa_mask, mask);
+ va_end(ap);
+
+ action.sa_flags = flags;
+ action.sa_restorer = NULL;
+ if(sigaction(sig, &action, NULL) < 0)
+ panic("sigaction failed - errno = %d\n", errno);
+
+ sigemptyset(&sig_mask);
+ sigaddset(&sig_mask, sig);
+ if(sigprocmask(SIG_UNBLOCK, &sig_mask, NULL) < 0)
+ panic("sigprocmask failed - errno = %d\n", errno);
+}
+
+int change_sig(int signal, int on)
+{
+ sigset_t sigset, old;
+
+ sigemptyset(&sigset);
+ sigaddset(&sigset, signal);
+ sigprocmask(on ? SIG_UNBLOCK : SIG_BLOCK, &sigset, &old);
+ return(!sigismember(&old, signal));
+}
+
+void block_signals(void)
+{
+ signals_enabled = 0;
+ /* This must return with signals disabled, so this barrier
+ * ensures that writes are flushed out before the return.
+ * This might matter if gcc figures out how to inline this and
+ * decides to shuffle this code into the caller.
+ */
+ mb();
+}
+
+void unblock_signals(void)
+{
+ int save_pending;
+
+ if(signals_enabled == 1)
+ return;
+
+ /* We loop because the IRQ handler returns with interrupts off. So,
+ * interrupts may have arrived and we need to re-enable them and
+ * recheck pending.
+ */
+ while(1){
+ /* Save and reset save_pending after enabling signals. This
+ * way, pending won't be changed while we're reading it.
+ */
+ signals_enabled = 1;
+
+ /* Setting signals_enabled and reading pending must
+ * happen in this order.
+ */
+ mb();
+
+ save_pending = pending;
+ if(save_pending == 0){
+ /* This must return with signals enabled, so
+ * this barrier ensures that writes are
+ * flushed out before the return. This might
+ * matter if gcc figures out how to inline
+ * this (unlikely, given its size) and decides
+ * to shuffle this code into the caller.
+ */
+ mb();
+ return;
+ }
+
+ pending = 0;
+
+ /* We have pending interrupts, so disable signals, as the
+ * handlers expect them off when they are called. They will
+ * be enabled again above.
+ */
+
+ signals_enabled = 0;
+
+ /* Deal with SIGIO first because the alarm handler might
+ * schedule, leaving the pending SIGIO stranded until we come
+ * back here.
+ */
+ if(save_pending & SIGIO_MASK)
+ CHOOSE_MODE_PROC(sig_handler_common_tt,
+ sig_handler_common_skas, SIGIO, NULL);
+
+ if(save_pending & SIGALRM_MASK)
+ real_alarm_handler(SIGALRM, NULL);
+
+ if(save_pending & SIGVTALRM_MASK)
+ real_alarm_handler(SIGVTALRM, NULL);
+ }
+}
+
+int get_signals(void)
+{
+ return signals_enabled;
+}
+
+int set_signals(int enable)
+{
+ int ret;
+ if(signals_enabled == enable)
+ return enable;
+
+ ret = signals_enabled;
+ if(enable)
+ unblock_signals();
+ else block_signals();
+
+ return ret;
+}
+
+void os_usr1_signal(int on)
+{
+ change_sig(SIGUSR1, on);
+}
git://git.onelab.eu / linux-2.6.git / blobdiff