syslog: simplify and model after lxc log functions

- add lxc_syslog_priority_to_string()
- add lxc_syslog_priority_to_int()
- remove syslog_facility struct
- add lxc.syslog to lxc_getconfig struct
- adapt config_syslog() callback

Signed-off-by: Christian Brauner <christian.brauner@mailbox.org>

src/lxc/conf.c

@@ -4168,6 +4168,7 @@ void lxc_conf_free(struct lxc_conf *conf)
 	free(conf->init_cmd);
 	free(conf->unexpanded_config);
 	free(conf->pty_names);
+	free(conf->syslog);
 	lxc_clear_config_network(conf);
 	free(conf->lsm_aa_profile);
 	free(conf->lsm_se_context);

src/lxc/conf.h

@@ -378,6 +378,10 @@ struct lxc_conf {
 
 	/* indicator if the container will be destroyed on shutdown */
 	int ephemeral;
+
+	/* The facility to pass to syslog. Let's users establish as what type of
+	 * program liblxc is supposed to write to the syslog. */
+	char *syslog;
 };
 
 #ifdef HAVE_TLS

src/lxc/confile.c

@@ -273,23 +273,6 @@ static const struct signame signames[] = {
 #endif
 };
 
-struct syslog_facility {
-	const char *name;
-	int facility;
-};
-
-static const struct syslog_facility syslog_facilities[] = {
-	{ "daemon",	LOG_DAEMON },
-	{ "local0",	LOG_LOCAL0 },
-	{ "local1",	LOG_LOCAL1 },
-	{ "local2",	LOG_LOCAL2 },
-	{ "local3",	LOG_LOCAL3 },
-	{ "local4",	LOG_LOCAL4 },
-	{ "local5",	LOG_LOCAL5 },
-	{ "local6",	LOG_LOCAL6 },
-	{ "local7",	LOG_LOCAL7 },
-};
-
 static const size_t config_size = sizeof(config)/sizeof(struct lxc_config_t);
 
 extern struct lxc_config_t *lxc_getconfig(const char *key)
@@ -2577,6 +2560,8 @@ int lxc_get_config_item(struct lxc_conf *c, const char *key, char *retv,
 		return lxc_get_conf_int(c, retv, inlen, c->init_gid);
 	else if (strcmp(key, "lxc.ephemeral") == 0)
 		return lxc_get_conf_int(c, retv, inlen, c->ephemeral);
+	else if (strcmp(key, "lxc.syslog") == 0)
+		v = c->syslog;
 	else return -1;
 
 	if (!v)
@@ -2959,17 +2944,13 @@ static int config_ephemeral(const char *key, const char *value,
 static int config_syslog(const char *key, const char *value,
 			 struct lxc_conf *lxc_conf)
 {
-	int n;
-	int facility = -1;
-
-	for (n = 0; n < sizeof(syslog_facilities) / sizeof((syslog_facilities)[0]); n++) {
-		if (strcasecmp(syslog_facilities[n].name, value) == 0) {
-			facility = syslog_facilities[n].facility;
-			lxc_log_syslog(facility);
-			return 0;
-		}
-	}
-
+	int facility;
+	facility = lxc_syslog_priority_to_int(value);
+	if (facility == -EINVAL) {
 		ERROR("Wrong value for lxc.syslog");
 		return -1;
 	}
+
+	lxc_log_syslog(facility);
+	return config_string_item(&lxc_conf->syslog, value);
+}

src/lxc/log.c

@@ -108,8 +108,9 @@ static int log_append_syslog(const struct lxc_log_appender *appender,
 	}
 
 	syslog(lxc_log_priority_to_syslog(event->priority),
-		"%s %s - %s:%s:%d - %s" ,
+		"%s%s %s - %s:%s:%d - %s" ,
 		log_vmname ? log_vmname : "",
+		log_vmname ? ":" : "",
 		event->category,
 		event->locinfo->file, event->locinfo->func,
 		event->locinfo->line,

src/lxc/log.h

@@ -26,12 +26,14 @@
 
 #include "config.h"
 
+#include <errno.h>
 #include <stdarg.h>
 #include <stdio.h>
 #include <sys/time.h>
 #include <string.h>
 #include <strings.h>
 #include <stdbool.h>
+#include <syslog.h>
 
 #include "conf.h"
 
@@ -53,7 +55,7 @@
 #define ATTR_UNUSED
 #endif
 
-/* predefined priorities. */
+/* predefined lxc log priorities. */
 enum lxc_loglevel {
 	LXC_LOG_PRIORITY_TRACE,
 	LXC_LOG_PRIORITY_DEBUG,
@@ -151,6 +153,24 @@ static inline const char* lxc_log_priority_to_string(int priority)
 		return "NOTSET";
 	}
 }
+
+static inline const char* lxc_syslog_priority_to_string(int priority)
+{
+	switch (priority) {
+	case LOG_DAEMON: return "daemon";
+	case LOG_LOCAL0: return "local0";
+	case LOG_LOCAL1: return "local1";
+	case LOG_LOCAL2: return "local2";
+	case LOG_LOCAL3: return "local3";
+	case LOG_LOCAL4: return "local4";
+	case LOG_LOCAL5: return "local5";
+	case LOG_LOCAL6: return "local6";
+	case LOG_LOCAL7: return "local7";
+	default:
+		return "NOTSET";
+	}
+}
+
 /*
  * converts a literal priority to an int
  */
@@ -169,6 +189,21 @@ static inline int lxc_log_priority_to_int(const char* name)
 	return LXC_LOG_PRIORITY_NOTSET;
 }
 
+static inline int lxc_syslog_priority_to_int(const char* name)
+{
+	if (!strcasecmp("daemon", name)) return LOG_DAEMON;
+	if (!strcasecmp("local0", name)) return LOG_LOCAL0;
+	if (!strcasecmp("local1", name)) return LOG_LOCAL1;
+	if (!strcasecmp("local2", name)) return LOG_LOCAL2;
+	if (!strcasecmp("local3", name)) return LOG_LOCAL3;
+	if (!strcasecmp("local4", name)) return LOG_LOCAL4;
+	if (!strcasecmp("local5", name)) return LOG_LOCAL5;
+	if (!strcasecmp("local6", name)) return LOG_LOCAL6;
+	if (!strcasecmp("local7", name)) return LOG_LOCAL7;
+
+	return -EINVAL;
+}
+
 static inline void
 __lxc_log_append(const struct lxc_log_appender *appender,
 		struct lxc_log_event* event)