2004-07-14 Paul Jakma <paul@dishone.st>
* sigevent.c: (quagga_signal_handler) add a global caught flag, set
the flags to a constant rather increment to be kinder.
(quagga_sigevent_process) new function, to do core of what
quagga_signal_timer did. dont block signals at all as sig->caught
is volatile sig_atomic_t and should be safe to access from signal
and normal contexts. The signal blocking is unneeded paranoia, but
is left intact under an ifdef, should some platform require it.
Check global caught flag before iterating through array.
(quagga_signal_timer) nearly everything moved to
quagga_sigevent_process. Left in under ifdef, in case some
platform could use a regular timer check for signals.
* sigevent.h: quagga_sigevent_process declaration.
* thread.c: (thread_fetch) check for signals at beginning of
scheduler loop, check for signals if select returns EINTR.
diff --git a/lib/sigevent.c b/lib/sigevent.c
index 6a2fd80..937180c 100644
--- a/lib/sigevent.c
+++ b/lib/sigevent.c
@@ -23,15 +23,16 @@
#include <sigevent.h>
#include <log.h>
+/* master signals descriptor struct */
struct quagga_sigevent_master_t
{
- struct thread_master *tm;
struct thread *t;
- struct quagga_signal_t *signals;
+ struct quagga_signal_t *signals;
int sigc;
-
-} sigmaster;
+
+ volatile sig_atomic_t caught;
+} sigmaster;
/* Generic signal handler
* Schedules signal event thread
@@ -47,20 +48,22 @@
sig = &(sigmaster.signals[i]);
if (sig->signal == signo)
- sig->caught++;
+ sig->caught = 1;
}
+
+ sigmaster.caught = 1;
}
+/* check if signals have been caught and run appropriate handlers */
int
-quagga_signal_timer (struct thread *t)
+quagga_sigevent_process (void)
{
- sigset_t newmask, oldmask;
- struct quagga_sigevent_master_t *sigm;
struct quagga_signal_t *sig;
int i;
+#ifdef SIGEVENT_BLOCK_SIGNALS
+ /* shouldnt need to block signals, but potentially may be needed */
+ sigset_t newmask, oldmask;
- sigm = THREAD_ARG (t);
-
/*
* Block most signals, but be careful not to defer SIGTRAP because
* doing so breaks gdb, at least on NetBSD 2.0. Avoid asking to
@@ -69,34 +72,57 @@
sigfillset (&newmask);
sigdelset (&newmask, SIGTRAP);
sigdelset (&newmask, SIGKILL);
-
+
if ( (sigprocmask (SIG_BLOCK, &newmask, &oldmask)) < 0)
{
zlog_err ("quagga_signal_timer: couldnt block signals!");
- sigm->t = thread_add_timer (sigm->tm, quagga_signal_timer,
- &sigmaster, QUAGGA_SIGNAL_TIMER_INTERVAL);
return -1;
}
-
- for (i = 0; i < sigm->sigc; i++)
+#endif /* SIGEVENT_BLOCK_SIGNALS */
+
+ if (sigmaster.caught > 0)
{
- sig = &(sigm->signals[i]);
- if (sig->caught > 0)
+ sigmaster.caught = 0;
+ /* must not read or set sigmaster.caught after here,
+ * race condition with per-sig caught flags if one does
+ */
+
+ for (i = 0; i < sigmaster.sigc; i++)
{
- sig->caught = 0;
- sig->handler();
+ sig = &(sigmaster.signals[i]);
+
+ if (sig->caught > 0)
+ {
+ sig->caught = 0;
+ sig->handler ();
+ }
}
}
-
- sigm->t = thread_add_timer (sigm->tm, quagga_signal_timer, &sigmaster,
- QUAGGA_SIGNAL_TIMER_INTERVAL);
+#ifdef SIGEVENT_BLOCK_SIGNALS
if ( sigprocmask (SIG_UNBLOCK, &oldmask, NULL) < 0 );
return -1;
-
+#endif /* SIGEVENT_BLOCK_SIGNALS */
+
return 0;
}
+#ifdef SIGEVENT_SCHEDULE_THREAD
+/* timer thread to check signals. Shouldnt be needed */
+int
+quagga_signal_timer (struct thread *t)
+{
+ struct quagga_sigevent_master_t *sigm;
+ struct quagga_signal_t *sig;
+ int i;
+
+ sigm = THREAD_ARG (t);
+ sigm->t = thread_add_timer (sigm->t->master, quagga_signal_timer, &sigmaster,
+ QUAGGA_SIGNAL_TIMER_INTERVAL);
+ return quagga_sigevent_process ();
+}
+#endif /* SIGEVENT_SCHEDULE_THREAD */
+
/* Initialization of signal handles. */
/* Signale wrapper. */
int
@@ -127,8 +153,8 @@
}
void
-signal_init (struct thread_master *m,
- int sigc, struct quagga_signal_t signals[])
+signal_init (struct thread_master *m, int sigc,
+ struct quagga_signal_t signals[])
{
int i = 0;
@@ -144,11 +170,10 @@
sigmaster.sigc = sigc;
sigmaster.signals = signals;
- sigmaster.tm = m;
-
+
+#ifdef SIGEVENT_SCHEDULE_THREAD
sigmaster.t =
thread_add_timer (m, quagga_signal_timer, &sigmaster,
QUAGGA_SIGNAL_TIMER_INTERVAL);
-
+#endif /* SIGEVENT_SCHEDULE_THREAD */
}
-