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/ChangeLog b/lib/ChangeLog
index 108a202..b3d452e 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,3 +1,20 @@
+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.
+
2004-07-13 Greg Troxel <gdt@poblano.ir.bbn.com>
* sigevent.c: Don't block SIGTRAP and SIGKILL. Blocking SIGTRAP
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 */
}
-
diff --git a/lib/sigevent.h b/lib/sigevent.h
index 6296736..20012af 100644
--- a/lib/sigevent.h
+++ b/lib/sigevent.h
@@ -23,6 +23,7 @@
#ifndef _QUAGGA_SIGNAL_H
#define _QUAGGA_SIGNAL_H
+
#include <thread.h>
#define QUAGGA_SIGNAL_TIMER_INTERVAL 2L
@@ -46,4 +47,7 @@
void signal_init (struct thread_master *m, int sigc,
struct quagga_signal_t *signals);
+/* check whether there are signals to handle, process any found */
+int quagga_sigevent_process (void);
+
#endif /* _QUAGGA_SIGNAL_H */
diff --git a/lib/thread.c b/lib/thread.c
index 93809f2..2e953c5 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -28,6 +28,7 @@
#include "log.h"
#include "hash.h"
#include "command.h"
+#include "sigevent.h"
static struct hash *cpu_record = NULL;
@@ -748,23 +749,26 @@
while (1)
{
- /* Normal event is the highest priority. */
+ /* Signals are highest priority */
+ quagga_sigevent_process ();
+
+ /* Normal event are the next highest priority. */
if ((thread = thread_trim_head (&m->event)) != NULL)
- return thread_run (m, thread, fetch);
+ return thread_run (m, thread, fetch);
/* Execute timer. */
gettimeofday (&timer_now, NULL);
for (thread = m->timer.head; thread; thread = thread->next)
- if (timeval_cmp (timer_now, thread->u.sands) >= 0)
- {
- thread_list_delete (&m->timer, thread);
- return thread_run (m, thread, fetch);
- }
+ if (timeval_cmp (timer_now, thread->u.sands) >= 0)
+ {
+ thread_list_delete (&m->timer, thread);
+ return thread_run (m, thread, fetch);
+ }
/* If there are any ready threads, process top of them. */
if ((thread = thread_trim_head (&m->ready)) != NULL)
- return thread_run (m, thread, fetch);
+ return thread_run (m, thread, fetch);
/* Structure copy. */
readfd = m->readfd;
@@ -777,16 +781,20 @@
num = select (FD_SETSIZE, &readfd, &writefd, &exceptfd, timer_wait);
if (num == 0)
- continue;
+ continue;
if (num < 0)
- {
- if (errno == EINTR)
- continue;
+ {
+ if (errno == EINTR)
+ {
+ /* signal received */
+ quagga_sigevent_process ();
+ continue;
+ }
- zlog_warn ("select() error: %s", strerror (errno));
- return NULL;
- }
+ zlog_warn ("select() error: %s", strerror (errno));
+ return NULL;
+ }
/* Normal priority read thead. */
ready = thread_process_fd (m, &m->read, &readfd, &m->readfd);
@@ -795,7 +803,7 @@
ready = thread_process_fd (m, &m->write, &writefd, &m->writefd);
if ((thread = thread_trim_head (&m->ready)) != NULL)
- return thread_run (m, thread, fetch);
+ return thread_run (m, thread, fetch);
}
}