Adding upstream version 3.4.23.upstream/3.4.23upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 314 insertions, 0 deletions

diff --git a/src/util/watchdog.c b/src/util/watchdog.c
new file mode 100644
index 0000000..3ec1fbc
--- /dev/null
+++ b/src/util/watchdog.c
@@ -0,0 +1,314 @@
+/*++
+/* NAME
+/*	watchdog 3
+/* SUMMARY
+/*	watchdog timer
+/* SYNOPSIS
+/*	#include <watchdog.h>
+/*
+/*	WATCHDOG *watchdog_create(timeout, action, context)
+/*	unsigned timeout;
+/*	void	(*action)(WATCHDOG *watchdog, char *context);
+/*	char	*context;
+/*
+/*	void	watchdog_start(watchdog)
+/*	WATCHDOG *watchdog;
+/*
+/*	void	watchdog_stop(watchdog)
+/*	WATCHDOG *watchdog;
+/*
+/*	void	watchdog_destroy(watchdog)
+/*	WATCHDOG *watchdog;
+/*
+/*	void	watchdog_pat()
+/* DESCRIPTION
+/*	This module implements watchdog timers that are based on ugly
+/*	UNIX alarm timers. The module is designed to survive systems
+/*	with clocks that jump occasionally.
+/*
+/*	Watchdog timers can be stacked. Only one watchdog timer can be
+/*	active at a time. Only the last created watchdog timer can be
+/*	manipulated. Watchdog timers must be destroyed in reverse order
+/*	of creation.
+/*
+/*	watchdog_create() suspends the current watchdog timer, if any,
+/*	and instantiates a new watchdog timer.
+/*
+/*	watchdog_start() starts or restarts the watchdog timer.
+/*
+/*	watchdog_stop() stops the watchdog timer.
+/*
+/*	watchdog_destroy() stops the watchdog timer, and resumes the
+/*	watchdog timer instance that was suspended by watchdog_create().
+/*
+/*	watchdog_pat() pats the watchdog, so it stays quiet.
+/*
+/*	Arguments:
+/* .IP timeout
+/*	The watchdog time limit. When the watchdog timer runs, the
+/*	process must invoke watchdog_start(), watchdog_stop() or
+/*	watchdog_destroy() before the time limit is reached.
+/* .IP action
+/*	A null pointer, or pointer to function that is called when the
+/*	watchdog alarm goes off. The default action is to terminate
+/*	the process with a fatal error.
+/* .IP context
+/*	Application context that is passed to the action routine.
+/* .IP watchdog
+/*	Must be a pointer to the most recently created watchdog instance.
+/*	This argument is checked upon each call.
+/* BUGS
+/*	UNIX alarm timers are not stackable, so there can be at most one
+/*	watchdog instance active at any given time.
+/* SEE ALSO
+/*	msg(3) diagnostics interface
+/* DIAGNOSTICS
+/*	Fatal errors: memory allocation problem, system call failure.
+/*	Panics: interface violations.
+/* LICENSE
+/* .ad
+/* .fi
+/*	The Secure Mailer license must be distributed with this software.
+/* AUTHOR(S)
+/*	Wietse Venema
+/*	IBM T.J. Watson Research
+/*	P.O. Box 704
+/*	Yorktown Heights, NY 10598, USA
+/*
+/*	Wietse Venema
+/*	Google, Inc.
+/*	111 8th Avenue
+/*	New York, NY 10011, USA
+/*--*/
+
+/* System library. */
+
+#include <sys_defs.h>
+#include <unistd.h>
+#include <signal.h>
+#include <posix_signals.h>
+
+/* Utility library. */
+
+#include <msg.h>
+#include <mymalloc.h>
+#include <killme_after.h>
+#include <watchdog.h>
+
+/* Application-specific. */
+
+ /*
+  * Rather than having one timer that goes off when it is too late, we break
+  * up the time limit into smaller intervals so that we can deal with clocks
+  * that jump occasionally.
+  */
+#define WATCHDOG_STEPS	3
+
+ /*
+  * UNIX alarms are not stackable, but we can save and restore state, so that
+  * watchdogs can at least be nested, sort of.
+  */
+struct WATCHDOG {
+    unsigned timeout;			/* our time resolution */
+    WATCHDOG_FN action;			/* application routine */
+    char   *context;			/* application context */
+    int     trip_run;			/* number of successive timeouts */
+    WATCHDOG *saved_watchdog;		/* saved state */
+    struct sigaction saved_action;	/* saved state */
+    unsigned saved_time;		/* saved state */
+};
+
+ /*
+  * However, only one watchdog instance can be current, and the caller has to
+  * restore state before a prior watchdog instance can be manipulated.
+  */
+static WATCHDOG *watchdog_curr;
+
+ /*
+  * Workaround for systems where the alarm signal does not wakeup the event
+  * machinery, and therefore does not restart the watchdog timer in the
+  * single_server etc. skeletons. The symptom is that programs abort when the
+  * watchdog timeout is less than the max_idle time.
+  */
+#ifdef USE_WATCHDOG_PIPE
+#include <errno.h>
+#include <iostuff.h>
+#include <events.h>
+
+static int watchdog_pipe[2];
+
+/* watchdog_read - read event pipe */
+
+static void watchdog_read(int unused_event, void *unused_context)
+{
+    char    ch;
+
+    while (read(watchdog_pipe[0], &ch, 1) > 0)
+	 /* void */ ;
+}
+
+#endif					/* USE_WATCHDOG_PIPE */
+
+/* watchdog_event - handle timeout event */
+
+static void watchdog_event(int unused_sig)
+{
+    const char *myname = "watchdog_event";
+    WATCHDOG *wp;
+
+    /*
+     * This routine runs as a signal handler. We should not do anything that
+     * could involve memory allocation/deallocation, but exiting without
+     * proper explanation would be unacceptable. For this reason, msg(3) was
+     * made safe for usage by signal handlers that terminate the process.
+     */
+    if ((wp = watchdog_curr) == 0)
+	msg_panic("%s: no instance", myname);
+    if (msg_verbose > 1)
+	msg_info("%s: %p %d", myname, (void *) wp, wp->trip_run);
+    if (++(wp->trip_run) < WATCHDOG_STEPS) {
+#ifdef USE_WATCHDOG_PIPE
+	int     saved_errno = errno;
+
+	/* Wake up the events(3) engine. */
+	if (write(watchdog_pipe[1], "", 1) != 1)
+	    msg_warn("%s: write watchdog_pipe: %m", myname);
+	errno = saved_errno;
+#endif
+	alarm(wp->timeout);
+    } else {
+	if (wp->action)
+	    wp->action(wp, wp->context);
+	else {
+	    killme_after(5);
+#ifdef TEST
+	    pause();
+#endif
+	    msg_fatal("watchdog timeout");
+	}
+    }
+}
+
+/* watchdog_create - create watchdog instance */
+
+WATCHDOG *watchdog_create(unsigned timeout, WATCHDOG_FN action, char *context)
+{
+    const char *myname = "watchdog_create";
+    struct sigaction sig_action;
+    WATCHDOG *wp;
+
+    wp = (WATCHDOG *) mymalloc(sizeof(*wp));
+    if ((wp->timeout = timeout / WATCHDOG_STEPS) == 0)
+	msg_panic("%s: timeout %d is too small", myname, timeout);
+    wp->action = action;
+    wp->context = context;
+    wp->saved_watchdog = watchdog_curr;
+    wp->saved_time = alarm(0);
+    sigemptyset(&sig_action.sa_mask);
+#ifdef SA_RESTART
+    sig_action.sa_flags = SA_RESTART;
+#else
+    sig_action.sa_flags = 0;
+#endif
+    sig_action.sa_handler = watchdog_event;
+    if (sigaction(SIGALRM, &sig_action, &wp->saved_action) < 0)
+	msg_fatal("%s: sigaction(SIGALRM): %m", myname);
+    if (msg_verbose > 1)
+	msg_info("%s: %p %d", myname, (void *) wp, timeout);
+#ifdef USE_WATCHDOG_PIPE
+    if (watchdog_curr == 0) {
+	if (pipe(watchdog_pipe) < 0)
+	    msg_fatal("%s: pipe: %m", myname);
+	non_blocking(watchdog_pipe[0], NON_BLOCKING);
+	non_blocking(watchdog_pipe[1], NON_BLOCKING);
+	close_on_exec(watchdog_pipe[0], CLOSE_ON_EXEC);	/* Fix 20190126 */
+	close_on_exec(watchdog_pipe[1], CLOSE_ON_EXEC);	/* Fix 20190126 */
+	event_enable_read(watchdog_pipe[0], watchdog_read, (void *) 0);
+    }
+#endif
+    return (watchdog_curr = wp);
+}
+
+/* watchdog_destroy - destroy watchdog instance, restore state */
+
+void    watchdog_destroy(WATCHDOG *wp)
+{
+    const char *myname = "watchdog_destroy";
+
+    watchdog_stop(wp);
+    watchdog_curr = wp->saved_watchdog;
+    if (sigaction(SIGALRM, &wp->saved_action, (struct sigaction *) 0) < 0)
+	msg_fatal("%s: sigaction(SIGALRM): %m", myname);
+    if (wp->saved_time)
+	alarm(wp->saved_time);
+    myfree((void *) wp);
+#ifdef USE_WATCHDOG_PIPE
+    if (watchdog_curr == 0) {
+	event_disable_readwrite(watchdog_pipe[0]);
+	(void) close(watchdog_pipe[0]);
+	(void) close(watchdog_pipe[1]);
+    }
+#endif
+    if (msg_verbose > 1)
+	msg_info("%s: %p", myname, (void *) wp);
+}
+
+/* watchdog_start - enable watchdog timer */
+
+void    watchdog_start(WATCHDOG *wp)
+{
+    const char *myname = "watchdog_start";
+
+    if (wp != watchdog_curr)
+	msg_panic("%s: wrong watchdog instance", myname);
+    wp->trip_run = 0;
+    alarm(wp->timeout);
+    if (msg_verbose > 1)
+	msg_info("%s: %p", myname, (void *) wp);
+}
+
+/* watchdog_stop - disable watchdog timer */
+
+void    watchdog_stop(WATCHDOG *wp)
+{
+    const char *myname = "watchdog_stop";
+
+    if (wp != watchdog_curr)
+	msg_panic("%s: wrong watchdog instance", myname);
+    alarm(0);
+    if (msg_verbose > 1)
+	msg_info("%s: %p", myname, (void *) wp);
+}
+
+/* watchdog_pat - pat the dog so it stays quiet */
+
+void    watchdog_pat(void)
+{
+    const char *myname = "watchdog_pat";
+
+    if (watchdog_curr)
+	watchdog_curr->trip_run = 0;
+    if (msg_verbose > 1)
+	msg_info("%s: %p", myname, (void *) watchdog_curr);
+}
+
+#ifdef TEST
+
+#include <vstream.h>
+
+int     main(int unused_argc, char **unused_argv)
+{
+    WATCHDOG *wp;
+
+    msg_verbose = 2;
+
+    wp = watchdog_create(10, (WATCHDOG_FN) 0, (void *) 0);
+    watchdog_start(wp);
+    do {
+	watchdog_pat();
+    } while (VSTREAM_GETCHAR() != VSTREAM_EOF);
+    watchdog_destroy(wp);
+    return (0);
+}
+
+#endif