From 778242986fc1d75e6f5c8cbac5d49fc3152984ef Mon Sep 17 00:00:00 2001
From: Kim Woelders <kw@thrane.eu>
Date: Tue, 17 Jul 2018 14:02:44 +0200
Subject: [PATCH] Debug tweaks

- Add gcc printf format check to _log()
- Show thread ids
- Enable setting debug level
---
 ttynvt.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/ttynvt.c b/ttynvt.c
index 2ebf337..c00856e 100644
--- a/ttynvt.c
+++ b/ttynvt.c
@@ -29,6 +29,9 @@
 
 #define RX_BUF_SIZE 1024
 
+#define _PRF_N_(no) __attribute__((__format__(__printf__, (no), (no) + 1)))
+#define _PRF2_ _PRF_N_(2)
+
 
 static struct ttynvt_param {
     unsigned int    major;
@@ -69,17 +72,28 @@ typedef struct ttynvt {
     tn_ctx_t       *tn;
 } ttynvt_t;
 
-static void _log(int prio, const char *fmt, ...)
+#include <sys/syscall.h>
+#define gettid() (pid_t)syscall(__NR_gettid)
+
+_PRF2_ static void _log(int prio, const char *fmt, ...)
 {
     va_list         arg;
+    char            buf[256];
 
     va_start(arg, fmt);
+#if 0
     vsyslog(prio, fmt, arg);
+#else
+    vsnprintf(buf, sizeof(buf), fmt, arg);
+    syslog(prio, "[%d] %s", gettid(), buf);
+#endif
     va_end(arg);
 }
 
 #define DBG(...) \
-    if (ttynvt_param.debug) _log(LOG_DEBUG, __VA_ARGS__)
+    if (ttynvt_param.debug > 0) _log(LOG_DEBUG, __VA_ARGS__)
+#define DBG2(...) \
+    if (ttynvt_param.debug > 1) _log(LOG_DEBUG, __VA_ARGS__)
 
 
 static int _check_dev(void)
@@ -812,7 +826,7 @@ static const struct cuse_lowlevel_ops ttynvt_op = {
 #define TTYNET_OPT(t, p, v) { t, offsetof(struct ttynvt_param, p), v }
 
 static const struct fuse_opt ttynvt_opts[] = {
-    TTYNET_OPT("-D", debug, 1),
+    TTYNET_OPT("-D %d", debug, 1),
     TTYNET_OPT("-M %u", major, 1),
     TTYNET_OPT("--maj=%u", major, 1),
     TTYNET_OPT("-m %u", minor, 1),
@@ -829,7 +843,7 @@ static const struct fuse_opt ttynvt_opts[] = {
 static void print_help(void)
 {
     fprintf(stderr, "ttynvt Usage:\n"
-            "\t-D\tEnable debug\n"
+            "\t-D level\tEnable debug\n"
             "\t-M major, --maj=major\n"
             "\t-m minor, --min=minor\n"
             "\t-n name, --name=name (default: ttyNVT0)\n"