server: log to syslog and stderr

As a daemon, let's log to syslog (and stderr).

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Reviewed-by: Ryan Neph <ryanneph@google.com>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>

server/main.c

@@ -27,8 +27,9 @@
 int
 main(int argc, char **argv)
 {
-   struct render_context_args ctx_args;
+   render_log_init();
 
+   struct render_context_args ctx_args;
    bool ok = render_server_main(argc, argv, &ctx_args);
 
    /* this is a subprocess */

server/render_common.c

@@ -7,6 +7,13 @@
 
 #include <stdarg.h>
 #include <stdio.h>
+#include <syslog.h>
+
+void
+render_log_init(void)
+{
+   openlog(NULL, LOG_NDELAY | LOG_PERROR | LOG_PID, LOG_USER);
+}
 
 void
 render_log(const char *fmt, ...)
@@ -14,10 +21,6 @@ render_log(const char *fmt, ...)
    va_list va;
 
    va_start(va, fmt);
-
-   fprintf(stderr, "render: ");
-   vfprintf(stderr, fmt, va);
-   fprintf(stderr, "\n");
-
+   vsyslog(LOG_DEBUG, fmt, va);
    va_end(va);
 }

server/render_common.h

@@ -29,6 +29,9 @@ struct render_virgl;
 struct render_worker;
 struct render_worker_jail;
 
+void
+render_log_init(void);
+
 void
 render_log(const char *fmt, ...);