* log.[ch]: add f2b_log_set_dest(), f2b_log_setup()

src/log.c

@@ -1,7 +1,11 @@
 #include "common.h"
 #include "log.h"
 
+#include "syslog.h"
+
 static log_msgtype_t minlevel = log_info;
+static enum { log_stderr = 0, log_file = 1, log_syslog = 2 } dest = log_stderr;
+static FILE *logfile = NULL;
 
 static const char *loglevels[] = {
   "debug",
@@ -11,9 +15,21 @@ static const char *loglevels[] = {
   "fatal",
 };
 
+static inline int
+get_facility(log_msgtype_t l) {
+  switch (l) {
+    case log_debug: return LOG_DEBUG;
+    case log_info:  return LOG_INFO;
+    case log_warn:  return LOG_WARNING;
+    case log_error: return LOG_ERR;
+    case log_fatal: return LOG_CRIT;
+      break;
+  }
+  return LOG_INFO;
+}
+
 void f2b_log_msg(log_msgtype_t l, const char *fmt, ...) {
   va_list args;
-  char line[LOGLINE_MAX] = "";
   char msg[LOGLINE_MAX]  = "";
 
   if (l < minlevel)
@@ -22,10 +38,20 @@ void f2b_log_msg(log_msgtype_t l, const char *fmt, ...) {
   va_start(args, fmt);
   vsnprintf(msg, sizeof(msg), fmt, args);
   va_end(args);
-  snprintf(line, LOGLINE_MAX, "[%s] %s", loglevels[l], msg);
-  /* TODO */
-  fputs(line, stderr);
-  fputc('\n', stderr);
+
+  if (!logfile)
+    logfile = stderr;
+
+  switch (dest) {
+    case log_syslog:
+      syslog(get_facility(l), "%s", msg);
+      break;
+    case log_stderr:
+    case log_file:
+    default:
+      fprintf(logfile, "[%s] %s\n", loglevels[l], msg);
+      break;
+  }
 
   return;
 }
@@ -37,3 +63,30 @@ void f2b_log_set_level(const char *level) {
   if (strcmp(level, "error") == 0) { minlevel = log_error; return; }
   if (strcmp(level, "fatal") == 0) { minlevel = log_fatal; return; }
 }
+
+void f2b_log_set_dest(const char *target) {
+  if (strcmp(target, "syslog") == 0) { dest = log_syslog; return; }
+  if (strcmp(target, "stderr") == 0) { dest = log_stderr; return; }
+  if (strcmp(target, "file")   == 0) { dest = log_file;   return; }
+}
+
+void f2b_log_setup(const char *path) {
+  switch (dest) {
+    case log_file:
+      if (logfile)
+        fclose(logfile);
+      if ((logfile = fopen(path, "a")) == NULL)
+        dest = log_stderr, logfile = stderr;
+      f2b_log_msg(log_error, "can't open logfile: %s -- %s", path, strerror(errno));
+      break;
+    case log_syslog:
+      openlog("f2b", LOG_CONS, LOG_DAEMON);
+      break;
+    case log_stderr:
+    default:
+      logfile = stderr;
+      break;
+  }
+
+  return;
+}

src/log.h

@@ -13,5 +13,7 @@ typedef enum {
 
 void f2b_log_msg(log_msgtype_t l, const char *fmt, ...);
 void f2b_log_set_level(const char *level);
+void f2b_log_set_dest (const char *dest);
+void f2b_log_setup    (const char *path);
 
 #endif /* F2B_LOG_H_ */