diff --git a/src/main.c b/src/main.c
index 2fd02c1..0ac06a2 100644
--- a/src/main.c
+++ b/src/main.c
@@ -7,6 +7,23 @@
 
 #include <getopt.h>
 #include <signal.h>
+#include <pwd.h>
+#include <grp.h>
+
+struct {
+  bool daemon;
+  uid_t uid;
+  gid_t gid;
+  char config_path[PATH_MAX];
+  char logfile_path[PATH_MAX];
+  char pidfile_path[PATH_MAX];
+} opts = {
+  true,
+  0, 0,
+  "/etc/f2b/f2b.conf",
+  "/var/log/f2b.log",
+  "/var/run/f2b.pid",
+};
 
 bool run  = true;
 bool rcfg = false;
@@ -31,23 +48,76 @@ void sa_hup(int signum) {
   }
 
 void usage(int exitcode) {
-  fprintf(stderr, "Usage: f2b -c <config>\n");
+  fprintf(stderr, "Usage: f2b [-c <config>] [-d] [-h]\n");
   exit(exitcode);
 }
 
+void
+update_opts_from_config(f2b_config_section_t *section) {
+  f2b_config_param_t *pa, *pb;
+
+  if (!section)
+    return;
+
+  /* set uid & gid. note: set only once if root */
+  if (opts.uid == 0 && (pa = f2b_config_param_find(section->param, "user")) != NULL) {
+    struct passwd *pw;
+    if ((pw = getpwnam(pa->value)) != NULL)
+      opts.uid = pw->pw_uid, opts.gid = pw->pw_gid;
+  }
+  if (opts.gid == 0 && (pa = f2b_config_param_find(section->param, "group")) != NULL) {
+    struct group *grp;
+    if ((grp = getgrnam(pa->value)) != NULL)
+      opts.gid = grp->gr_gid;
+  }
+
+  if (opts.daemon == false && (pa = f2b_config_param_find(section->param, "daemon")) != NULL) {
+    if (strcmp(pa->value, "yes") == 0)
+      opts.daemon = true;
+  }
+
+  /* setup logging */
+  if ((pa = f2b_config_param_find(section->param, "loglevel")) != NULL)
+    f2b_log_set_level(pa->value);
+
+  pa = f2b_config_param_find(section->param, "logdest");
+  pb = f2b_config_param_find(section->param, "logfile");
+  if (pa) {
+    if (!opts.daemon && strcmp(pa->value, "stderr") == 0) {
+      f2b_log_to_stderr();
+    } else if (strcmp(pa->value, "file") == 0) {
+      if (pb && *pb->value != '\0') {
+        size_t len = sizeof(opts.logfile_path);
+        strncpy(opts.logfile_path, pb->value, len - 1);
+        opts.logfile_path[len - 1] = '\0';
+        f2b_log_to_file(opts.logfile_path);
+      } else {
+        f2b_log_msg(log_warn, "you must set 'logfile' option with 'logdest = file'");
+        f2b_log_to_syslog();
+      }
+    } else {
+      f2b_log_to_syslog();
+    }
+  }
+
+  /* TODO: */
+}
+
 int main(int argc, char *argv[]) {
   struct sigaction act;
   f2b_config_t config;
   f2b_config_section_t *section = NULL;
   f2b_jail_t *jails = NULL;
   f2b_jail_t *jail  = NULL;
-  char *config_file = NULL;
   char opt = '\0';
 
-  while ((opt = getopt(argc, argv, "c:h")) != -1) {
+  while ((opt = getopt(argc, argv, "c:dh")) != -1) {
     switch (opt) {
       case 'c':
-        config_file = optarg;
+        strncpy(opts.config_path, optarg, sizeof(opts.config_path));
+        break;
+      case 'd':
+        opts.daemon = true;
         break;
       case 'h':
         usage(EXIT_SUCCESS);
@@ -61,13 +131,41 @@ int main(int argc, char *argv[]) {
   SA_REGISTER(SIGTERM, &sa_term);
   SA_REGISTER(SIGHUP,  &sa_hup);
 
-  if (!config_file)
+  if (opts.config_path[0] == '\0')
     usage(EXIT_FAILURE);
   memset(&config, 0x0, sizeof(config));
-  if (f2b_config_load(&config, config_file, true) != true) {
-    f2b_log_msg(log_error, "can't load config from '%s'", config_file);
+  if (f2b_config_load(&config, opts.config_path, true) != true) {
+    f2b_log_msg(log_error, "can't load config from '%s'", opts.config_path);
     return EXIT_FAILURE;
   }
+  update_opts_from_config(config.main);
+
+  if (opts.daemon) {
+    pid_t pid = fork();
+    if (pid > 0)
+      exit(EXIT_SUCCESS);
+      /* parent */
+    if (pid < 0) {
+      /* parent */
+      perror("child: fork() failed");
+      exit(EXIT_FAILURE);
+    }
+    /* child */
+    setsid();
+    if (getuid() == 0 &&
+        (setuid(opts.uid) != 0 ||
+         setgid(opts.gid) != 0)) {
+      perror("child: setuid()/setgid() failed");
+      exit(EXIT_FAILURE);
+    }
+    if (chdir("/") != 0 ||
+        freopen("/dev/null", "r", stdin)  == NULL ||
+        freopen("/dev/null", "w", stdout) == NULL ||
+        freopen("/dev/null", "w", stderr) == NULL) {
+      perror("child: freopen() failed");
+      exit(EXIT_FAILURE);
+    }
+  }
 
   if (config.defaults)
     f2b_jail_set_defaults(config.defaults);