logging

src/Makefile

@@ -3,7 +3,7 @@ CC=gcc
 CFLAGS=-Wall
 LDFLAGS=-lwiringPi -lcurl -lconfig
 
-counter:	counter.o LS7366R.o influx.o ringbuffer.o led.o
+counter:	counter.o LS7366R.o influx.o ringbuffer.o led.o logging.o
 	$(CC) -o $@ $(LDFLAGS) $^
 
 .c.o:

src/counter.c

@@ -10,6 +10,7 @@
 #include "influx.h"
 #include "ringbuffer.h"
 #include "led.h"
+#include "logging.h"
 
 
 const int CTRL_OUT = 16;
@@ -51,9 +52,9 @@ void init() {
 void readConfig() {
   config_init(&cfg);
   if (! config_read_file(&cfg, "/opt/etc/counter.cfg")) {
-    fprintf(stderr, "failed to read config file: %s:%d - %s\n",
-            config_error_file(&cfg), config_error_line(&cfg),
-            config_error_text(&cfg));
+    logmsg(LOG_ERR, "failed to read config file: %s:%d - %s\n",
+        config_error_file(&cfg), config_error_line(&cfg),
+        config_error_text(&cfg));
     config_destroy(&cfg);
     exit(-1);
   }
@@ -87,7 +88,7 @@ int main (void) {
     double f = 1.0 / (((double) diff) / 1000000.0);
 
     if (settled && (abs(f - lastF) > epsilon)) {
-      fprintf(stderr, "Current f=%f, last f=%f, gradient too large, skipped\n", f, lastF);
+      logmsg(LOG_INFO, "Current f=%f, last f=%f, gradient too large, skipped\n", f, lastF);
       skipped++;
       f = lastF;
     }
@@ -100,7 +101,7 @@ int main (void) {
       ledTick = 0;
       led(E_GREEN, false);
       if (! settled) {
-        fprintf(stderr, "Now it is settled\n");
+        logmsg(LOG_INFO, "Now it is settled\n");
         settled = true;
       }
     }

src/influx.c

@@ -7,6 +7,7 @@
 #include <libconfig.h>
 
 #include "led.h"
+#include "logging.h"
 
 
 const char INFLUXURL_KEY[] = "influxUrl";
@@ -70,7 +71,7 @@ static void influxSendRequest() {
         curl_easy_setopt(curl, CURLOPT_POSTFIELDS, influxBuffer);
         CURLcode res = curl_easy_perform(curl);
         if(res != CURLE_OK) {
-            fprintf(stderr, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
+            logmsg(LOG_ERR, "curl_easy_perform() failed: %s\n", curl_easy_strerror(res));
             led(E_RED, true);
         }
         curl_easy_cleanup(curl);
@@ -92,7 +93,7 @@ void influxAddFrequency(double f) {
         influxSendRequest();
         influxClearBuffer();
         totalEntries += entries;
-        fprintf(stderr, "%u entries sent to database, in total %u, skipped: %u\n", entries, totalEntries, skipped);
+        logmsg(LOG_INFO, "%u entries sent to database, in total %u, skipped: %u\n", entries, totalEntries, skipped);
         entries = 0;
     }
 

src/logging.c

@@ -0,0 +1,13 @@
+#include <syslog.h>
+#include <stdarg.h>
+
+void logmsg(int prio, const char* format, ...) {
+  va_list vl;
+  
+  openlog("counter", 0, LOG_LOCAL0);
+  va_start(vl, format);
+  vsyslog(prio, format, vl);
+  va_end(vl);
+  closelog();
+}
+

src/logging.h

@@ -0,0 +1,8 @@
+#ifndef _LOGGING_H_
+#define _LOGGING_H_
+
+#include <syslog.h>
+
+void logmsg(int prio, const char* format, ...);
+
+#endif // _LOGGING_H_