Initial implementation of zed (ZFS Event Daemon)

zed monitors ZFS events.  When a zevent is posted, zed will run any
scripts that have been enabled for the corresponding zevent class.
Multiple scripts may be invoked for a given zevent.  The zevent
nvpairs are passed to the scripts as environment variables.

Events are processed synchronously by the single thread, and there is
no maximum timeout for script execution.  Consequently, a misbehaving
script can delay (or forever block) the processing of subsequent
zevents.  Plans are to address this in future commits.

Initial scripts have been developed to log events to syslog
and send email in response to checksum/data/io errors and
resilver.finish/scrub.finish events.  By default, email will only
be sent if the ZED_EMAIL variable is configured in zed.rc (which is
serving as a config file of sorts until a proper configuration file
is implemented).

Signed-off-by: Chris Dunlap <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Issue #2

1 files changed, 171 insertions, 0 deletions

diff --git a/cmd/zed/zed_log.c b/cmd/zed/zed_log.c
new file mode 100644
index 000000000..bc432bc21
--- /dev/null
+++ b/cmd/zed/zed_log.c
@@ -0,0 +1,171 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license from the top-level
+ * OPENSOLARIS.LICENSE or <http://opensource.org/licenses/CDDL-1.0>.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each file
+ * and include the License file from the top-level OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049).
+ * Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC.
+ */
+
+#include <assert.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include "zed_log.h"
+
+#define	ZED_LOG_MAX_ID_LEN	64
+#define	ZED_LOG_MAX_LOG_LEN	1024
+
+static struct {
+	unsigned do_stderr:1;
+	unsigned do_syslog:1;
+	int level;
+	char id[ZED_LOG_MAX_ID_LEN];
+} _ctx;
+
+void
+zed_log_init(const char *identity)
+{
+	const char *p;
+
+	if (identity) {
+		p = (p = strrchr(identity, '/')) ? p + 1 : identity;
+		strlcpy(_ctx.id, p, sizeof (_ctx.id));
+	} else {
+		_ctx.id[0] = '\0';
+	}
+}
+
+void
+zed_log_fini()
+{
+	if (_ctx.do_syslog) {
+		closelog();
+	}
+}
+
+void
+zed_log_stderr_open(int level)
+{
+	_ctx.do_stderr = 1;
+	_ctx.level = level;
+}
+
+void
+zed_log_stderr_close(void)
+{
+	_ctx.do_stderr = 0;
+}
+
+void
+zed_log_syslog_open(int facility)
+{
+	const char *identity;
+
+	_ctx.do_syslog = 1;
+	identity = (_ctx.id[0] == '\0') ? NULL : _ctx.id;
+	openlog(identity, LOG_NDELAY, facility);
+}
+
+void
+zed_log_syslog_close(void)
+{
+	_ctx.do_syslog = 0;
+	closelog();
+}
+
+static void
+_zed_log_aux(int priority, const char *fmt, va_list vargs)
+{
+	char buf[ZED_LOG_MAX_LOG_LEN];
+	char *syslogp;
+	char *p;
+	int len;
+	int n;
+
+	assert(fmt != NULL);
+
+	syslogp = NULL;
+	p = buf;
+	len = sizeof (buf);
+
+	if (_ctx.id[0] != '\0') {
+		n = snprintf(p, len, "%s: ", _ctx.id);
+		if ((n < 0) || (n >= len)) {
+			p += len - 1;
+			len = 0;
+		} else {
+			p += n;
+			len -= n;
+		}
+	}
+	if ((len > 0) && fmt) {
+		syslogp = p;
+		n = vsnprintf(p, len, fmt, vargs);
+		if ((n < 0) || (n >= len)) {
+			p += len - 1;
+			len = 0;
+		} else {
+			p += n;
+			len -= n;
+		}
+	}
+	*p = '\0';
+
+	if (_ctx.do_syslog && syslogp)
+		syslog(priority, "%s", syslogp);
+
+	if (_ctx.do_stderr && priority <= _ctx.level)
+		fprintf(stderr, "%s\n", buf);
+}
+
+/*
+ * Log a message at the given [priority] level specified by the printf-style
+ *   format string [fmt].
+ */
+void
+zed_log_msg(int priority, const char *fmt, ...)
+{
+	va_list vargs;
+
+	if (fmt) {
+		va_start(vargs, fmt);
+		_zed_log_aux(priority, fmt, vargs);
+		va_end(vargs);
+	}
+}
+
+/*
+ * Log a fatal error message specified by the printf-style format string [fmt].
+ */
+void
+zed_log_die(const char *fmt, ...)
+{
+	va_list vargs;
+
+	if (fmt) {
+		va_start(vargs, fmt);
+		_zed_log_aux(LOG_ERR, fmt, vargs);
+		va_end(vargs);
+	}
+	exit(EXIT_FAILURE);
+}