GUAC-911: Only log up to specified log level. Add comments to log.h.

src/guacd/daemon.c

@@ -392,7 +392,8 @@ int main(int argc, char* argv[]) {
     /* Set up logging prefix */
     strncpy(log_prefix, basename(argv[0]), sizeof(log_prefix));
 
-    /* Open log as early as we can */
+    /* Init logging as early as possible */
+    log_level = config->max_log_level;
     openlog("guacd", LOG_PID, LOG_DAEMON);
 
     /* Log start */

src/guacd/log.c

@@ -21,6 +21,7 @@
  */
 
 #include "config.h"
+#include "log.h"
 
 #include <guacamole/client.h>
 #include <guacamole/error.h>
@@ -33,14 +34,21 @@
 /* Log prefix, defaulting to "guacd" */
 char log_prefix[64] = "guacd";
 
+int log_level = GUAC_LOG_INFO;
+
 void vguacd_log(guac_client_log_level level, const char* format,
         va_list args) {
 
     const char* priority_name;
     int priority;
 
-    /* Copy log message into buffer */
     char message[2048];
+
+    /* Don't bother if the log level is too high */
+    if (level > log_level)
+        return;
+
+    /* Copy log message into buffer */
     vsnprintf(message, sizeof(message), format, args);
 
     /* Convert log level to syslog priority */

src/guacd/log.h

@@ -28,14 +28,49 @@
 
 #include <guacamole/client.h>
 
+/**
+ * The maximum level at which to log messages. All other messages will be
+ * dropped.
+ */
+extern int log_level;
+
+/**
+ * The string to prepend to all log messages.
+ */
 extern char log_prefix[64];
 
+/**
+ * Writes a message to guacd's logs. This function takes a format and va_list,
+ * similar to vprintf.
+ */
 void vguacd_log(guac_client_log_level level, const char* format, va_list args);
+
+/**
+ * Writes a message to guacd's logs. This function accepts parameters
+ * identically to printf.
+ */
 void guacd_log(guac_client_log_level level, const char* format, ...);
 
-void guacd_client_log(guac_client* client, guac_client_log_level level, const char* format, va_list args);
+/**
+ * Writes a message using the logging facilities of the given client,
+ * automatically including any information present in guac_error. This function
+ * accepts parameters identically to printf.
+ */
+void guacd_client_log(guac_client* client, guac_client_log_level level,
+        const char* format, va_list args);
 
+/**
+ * Prints an error message to guacd's logs, automatically including any
+ * information present in guac_error. This function accepts parameters
+ * identically to printf.
+ */
 void guacd_log_guac_error(const char* message);
+
+/**
+ * Prints an error message using the logging facilities of the given client,
+ * automatically including any information present in guac_error. This function
+ * accepts parameters identically to printf.
+ */
 void guacd_client_log_guac_error(guac_client* client, const char* message);
 
 #endif