Add dummy logging implementation

The dummy log is the default and is effectively a NOP. It's set in case
the user forgets to use a real logging backend (syslog is the only other
supported logging backend right now).
Signed-off-by: Shawn Webb <shawn.webb@hardenedbsd.org>

Makefile

@@ -3,6 +3,7 @@ SHLIB_MAJOR=	0
 INCS=		liblattutil.h
 
 SRCS+=		config.c
+SRCS+=		log-dummy.c
 SRCS+=		log-main.c
 SRCS+=		log-syslog.c
 

include/liblattutil.h

@@ -159,6 +159,33 @@ void lattutil_log_free(lattutil_log_t **);
  */
 bool lattutil_log_syslog_init(lattutil_log_t *, int, int);
 
+/**
+ * Initialize NULL logging
+ *
+ * This is the default logger. It simply discards all logging
+ * messages.
+ *
+ * @param Logging object
+ */
+void lattutil_log_dummy_init(lattutil_log_t *);
+
+/**
+ * Determine if the logging subsystem is ready to receive messages
+ *
+ * @param Pointer to the logging object
+ */
+bool lattutil_log_ready(lattutil_log_t *);
+
+/**
+ * Get the configured minimum verbosity level
+ *
+ * @param Logging object
+ * @return Verbosity level
+ */
+int lattutil_log_verbosity(lattutil_log_t *);
+
+int lattutil_log_set_verbosity(lattutil_log_t *, int);
+
 #ifdef _lattutil_internal
 ssize_t lattutil_log_syslog_err(lattutil_log_t *, int,
     const char *, ...);
@@ -167,6 +194,14 @@ ssize_t lattutil_log_syslog_info(lattutil_log_t *, int,
 ssize_t lattutil_log_syslog_warn(lattutil_log_t *, int,
     const char *, ...);
 void lattutil_log_syslog_close(lattutil_log_t *);
+
+ssize_t lattutil_log_dummy_err(lattutil_log_t *, int,
+    const char *, ...);
+ssize_t lattutil_log_dummy_info(lattutil_log_t *, int,
+    const char *, ...);
+ssize_t lattutil_log_dummy_warn(lattutil_log_t *, int,
+    const char *, ...);
+void lattutil_log_dummy_close(lattutil_log_t *);
 #endif /* _lattutil_internal */
 
 #endif /* !_LIBLATTUTIL_H */

src/log-dummy.c

+/*-
+ * Copyright (c) 2021 Shawn Webb <shawn.webb@hardenedbsd.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "liblattutil.h"
+
+EXPORTED_SYM
+void
+lattutil_log_dummy_init(lattutil_log_t *res)
+{
+
+	res->ll_log_close = lattutil_log_dummy_close;
+	res->ll_log_err = lattutil_log_dummy_err;
+	res->ll_log_info = lattutil_log_dummy_info;
+	res->ll_log_warn = lattutil_log_dummy_warn;
+}
+
+ssize_t
+lattutil_log_dummy_err(lattutil_log_t *logp, int verbose,
+    const char *fmt, ...)
+{
+
+	return (0);
+}
+
+ssize_t
+lattutil_log_dummy_info(lattutil_log_t *logp, int verbose,
+    const char *fmt, ...)
+{
+
+	return (0);
+}
+
+ssize_t
+lattutil_log_dummy_warn(lattutil_log_t *logp, int verbose,
+    const char *fmt, ...)
+{
+
+	return (0);
+}
+
+void
+lattutil_log_dummy_close(lattutil_log_t *logp)
+{
+
+	return;
+}

src/log-main.c

@@ -52,6 +52,8 @@ lattutil_log_init(char *path, int verbosity)
 		}
 	}
 
+	lattutil_log_dummy_init(res);
+
 	return (res);
 }
 
@@ -78,24 +80,51 @@ lattutil_log_free(lattutil_log_t **logp)
 
 EXPORTED_SYM
 bool
-lattutil_log_syslog_init(lattutil_log_t *logp, int logopt, int facility)
+lattutil_log_ready(lattutil_log_t *logp)
 {
-	const char *name;
-
-	logp->ll_log_close = lattutil_log_syslog_close;
-	logp->ll_log_err = lattutil_log_syslog_err;
-	logp->ll_log_info = lattutil_log_syslog_info;
-	logp->ll_log_warn = lattutil_log_syslog_warn;
-
-	name = logp->ll_path;
-	if (name == NULL) {
-		name = getprogname();
-		if (name == NULL) {
-			name = LATTUTIL_LOG_DEFAULT_NAME;
-		}
+
+	if (logp == NULL) {
+		return (false);
 	}
 
-	openlog(name, logopt, facility);
+	if (logp->ll_log_err == NULL ||
+	    logp->ll_log_info == NULL ||
+	    logp->ll_log_warn == NULL) {
+		return (false);
+	}
 
 	return (true);
 }
+
+EXPORTED_SYM
+int
+lattutil_log_verbosity(lattutil_log_t *logp)
+{
+
+	if (logp == NULL) {
+		return (-1);
+	}
+
+	return (logp->ll_verbosity);
+}
+
+EXPORTED_SYM
+int
+lattutil_log_set_verbosity(lattutil_log_t *logp, int verbosity)
+{
+	int old;
+
+	if (logp == NULL) {
+		return (-1);
+	}
+
+	old = logp->ll_verbosity;
+
+	if (verbosity == -1) {
+		verbosity = LATTUTIL_LOG_VERBOSITY_DEFAULT;
+	}
+
+	logp->ll_verbosity = verbosity;
+
+	return (old);
+}

src/log-syslog.c

@@ -31,6 +31,30 @@
 
 #include "liblattutil.h"
 
+EXPORTED_SYM
+bool
+lattutil_log_syslog_init(lattutil_log_t *logp, int logopt, int facility)
+{
+	const char *name;
+
+	logp->ll_log_close = lattutil_log_syslog_close;
+	logp->ll_log_err = lattutil_log_syslog_err;
+	logp->ll_log_info = lattutil_log_syslog_info;
+	logp->ll_log_warn = lattutil_log_syslog_warn;
+
+	name = logp->ll_path;
+	if (name == NULL) {
+		name = getprogname();
+		if (name == NULL) {
+			name = LATTUTIL_LOG_DEFAULT_NAME;
+		}
+	}
+
+	openlog(name, logopt, facility);
+
+	return (true);
+}
+
 ssize_t
 lattutil_log_syslog_err(lattutil_log_t *logp, int verbose,
     const char *fmt, ...)