log: add support for logging to syslogd

include/villas/log.h

@@ -31,6 +31,7 @@ extern "C" {
 #include <time.h>
 #include <sys/ioctl.h>
 
+#include "advio.h"
 #include "common.h"
 #include "log_config.h"
 
@@ -99,6 +100,8 @@ struct log {
 	long facilities;	/**< Debug facilities used by the debug() macro. */
 	const char *path;	/**< Path of the log file. */
 	char *prefix;		/**< Prefix each line with this string. */
+	int syslog;		/**< Whether or not to log to syslogd. */
+
 	FILE *file;		/**< Send all log output to this file / stdout / stderr. */
 };
 

lib/log.c

@@ -26,6 +26,7 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <syslog.h>
 
 #include "config.h"
 #include "log.h"
@@ -128,6 +129,7 @@ int log_init(struct log *l, int level, long facilitites)
 	global_log = l;
 
 	l->level = level;
+	l->syslog = 0;
 	l->facilities = facilitites;
 	l->file = stderr;
 	l->path = NULL;
@@ -162,14 +164,22 @@ int log_init(struct log *l, int level, long facilitites)
 
 int log_start(struct log *l)
 {
-	l->file = l->path ? fopen(l->path, "a+") : stderr;
-	if (!l->file) {
-		l->file = stderr;
-		error("Failed to open log file '%s'", l->path);
+	if (l->path) {
+		l->file = fopen(l->path, "a+");;
+		if (!l->file) {
+			l->file = stderr;
+			error("Failed to open log file '%s'", l->path);
+		}
 	}
+	else
+		l->file = stderr;
 
 	l->state = STATE_STARTED;
 
+	if (l->syslog) {
+		openlog(NULL, LOG_PID, LOG_DAEMON);
+	}
+
 	debug(LOG_LOG | 5, "Log sub-system started: level=%d, faciltities=%#lx, path=%s", l->level, l->facilities, l->path);
 
 	return 0;
@@ -177,9 +187,15 @@ int log_start(struct log *l)
 
 int log_stop(struct log *l)
 {
-	if (l->state == STATE_STARTED) {
-		if (l->file != stderr && l->file != stdout)
-			fclose(l->file);
+	if (l->state != STATE_STARTED)
+		return 0;
+
+	if (l->file != stderr && l->file != stdout) {
+		fclose(l->file);
+	}
+
+	if (l->syslog) {
+		closelog();
 	}
 
 	l->state = STATE_STOPPED;

lib/log_config.c

@@ -23,6 +23,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <syslog.h>
 
 #include "config.h"
 #include "log.h"
@@ -38,10 +39,11 @@ int log_parse(struct log *l, json_t *cfg)
 
 	json_error_t err;
 
-	ret = json_unpack_ex(cfg, &err, 0, "{ s?: i, s?: s, s?: s }",
+	ret = json_unpack_ex(cfg, &err, 0, "{ s?: i, s?: s, s?: s, s?: b }",
 		"level", &l->level,
 		"file", &path,
-		"facilities", &facilities
+		"facilities", &facilities,
+		"syslog", &l->syslog
 	);
 	if (ret)
 		jerror(&err, "Failed to parse logging configuration");
@@ -71,6 +73,9 @@ void jerror(json_error_t *err, const char *fmt, ...)
 	log_print(l, LOG_LVL_ERROR, "%s:", buf);
 	{ INDENT
 		log_print(l, LOG_LVL_ERROR, "%s in %s:%d:%d", err->text, err->source, err->line, err->column);
+
+		if (l->syslog)
+			syslog(LOG_ERR, "%s in %s:%d:%d", err->text, err->source, err->line, err->column);
 	}
 
 	free(buf);

lib/log_helper.c

@@ -22,6 +22,7 @@
 
 #include <errno.h>
 #include <unistd.h>
+#include <syslog.h>
 
 #include "utils.h"
 #include "log.h"
@@ -37,7 +38,12 @@ void debug(long class, const char *fmt, ...)
 
 	if (((fac == 0) || (fac & l->facilities)) && (lvl <= l->level)) {
 		va_start(ap, fmt);
+
 		log_vprint(l, LOG_LVL_DEBUG, fmt, ap);
+
+		if (l->syslog)
+			syslog(LOG_DEBUG, fmt, ap);
+
 		va_end(ap);
 	}
 }
@@ -49,7 +55,12 @@ void info(const char *fmt, ...)
 	struct log *l = global_log;
 
 	va_start(ap, fmt);
+
 	log_vprint(l, LOG_LVL_INFO, fmt, ap);
+
+	if (l->syslog)
+		syslog(LOG_INFO, fmt, ap);
+
 	va_end(ap);
 }
 
@@ -60,7 +71,12 @@ void warn(const char *fmt, ...)
 	struct log *l = global_log;
 
 	va_start(ap, fmt);
+
 	log_vprint(l, LOG_LVL_WARN, fmt, ap);
+
+	if (l->syslog)
+		syslog(LOG_WARNING, fmt, ap);
+
 	va_end(ap);
 }
 
@@ -71,7 +87,12 @@ void stats(const char *fmt, ...)
 	struct log *l = global_log;
 
 	va_start(ap, fmt);
+
 	log_vprint(l, LOG_LVL_STATS, fmt, ap);
+
+	if (l->syslog)
+		syslog(LOG_INFO, fmt, ap);
+
 	va_end(ap);
 }
 
@@ -82,7 +103,12 @@ void error(const char *fmt, ...)
 	struct log *l = global_log;
 
 	va_start(ap, fmt);
+
 	log_vprint(l, LOG_LVL_ERROR, fmt, ap);
+
+	if (l->syslog)
+		syslog(LOG_ERR, fmt, ap);
+
 	va_end(ap);
 
 	killme(SIGABRT);
@@ -102,6 +128,9 @@ void serror(const char *fmt, ...)
 
 	log_print(l, LOG_LVL_ERROR, "%s: %m (%u)", buf, errno);
 
+	if (l->syslog)
+		syslog(LOG_ERR, "%s: %m (%u)", buf, errno);
+
 	free(buf);
 
 	killme(SIGABRT);