Change how rlimit is set

Last release changed to using the systemd LimitNOFILE=16384. This also
has the effect of changing the hard rlimit to the same number. If we
instead call getrlimit and set the soft limit to the hard limit, we
can have more descriptors available.

Also correct the error detection of failed nice syscalls.

init/fapolicyd.service

@@ -6,7 +6,6 @@ Documentation=man:fapolicyd(8)
 
 [Service]
 OOMScoreAdjust=-1000
-LimitNOFILE=16384
 Type=forking
 PIDFile=/run/fapolicyd.pid
 ExecStartPre=/usr/sbin/fagenrules

src/daemon/fapolicyd.c

@@ -516,12 +516,21 @@ int main(int argc, const char *argv[])
 	limit.rlim_cur = RLIM_INFINITY;
 	limit.rlim_max = RLIM_INFINITY;
 	setrlimit(RLIMIT_FSIZE, &limit);
+	getrlimit(RLIMIT_NOFILE, &limit);
+	if (limit.rlim_max >= 16384)
+		limit.rlim_cur = limit.rlim_max;
+	else
+		limit.rlim_cur = 16834;
 	if (setrlimit(RLIMIT_NOFILE, &limit))
 		msg(LOG_WARNING, "Can't increase file number rlimit - %s",
 		    strerror(errno));
+	else
+		msg(LOG_INFO, "Can handle %u file descriptors", limit.rlim_cur);
 
 	// get more time slices because everything is waiting on us
-	if (nice(-config.nice_val))
+	errno = 0;
+	nice(-config.nice_val);
+	if (errno)
 		msg(LOG_WARNING, "Couldn't adjust priority (%s)",
 				strerror(errno));