debug: Optimise construction of header_str_no_nl

If it isn't used then it isn't copied.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Volker Lendecke <vl@samba.org>

diff --git a/lib/util/debug.c b/lib/util/debug.c
index 27fdf03e21a5cd422ea035796a945ec7eefff549..d48a56ee70dab1b7d49903c8c2406c0b4256670a 100644 (file)
--- a/lib/util/debug.c
+++ b/lib/util/debug.c
@@ -225,6 +225,27 @@ static void copy_no_nl(char *out,
        memcpy(out, in, len);
        out[len] = '\0';
 }
+
+#if defined(HAVE_LIBSYSTEMD_JOURNAL) || defined(HAVE_LIBSYSTEMD) || \
+       defined(HAVE_LTTNG_TRACEF) || defined(HAVE_GPFS)
+static void ensure_copy_no_nl(char *out,
+                             size_t out_size,
+                             const char *in,
+                             size_t in_len)
+{
+       /*
+        * Assume out is a static buffer that is reused as a cache.
+        * If it isn't empty then this has already been done with the
+        * same input.
+        */
+       if (out[0] != '\0') {
+               return;
+       }
+
+       copy_no_nl(out, out_size, in, in_len);
+}
+#endif
+
 /* -------------------------------------------------------------------------- **
  * Debug backends. When logging to DEBUG_FILE, send the log entries to
  * all active backends.
@@ -314,6 +335,10 @@ static void debug_systemd_log(int msg_level,
                              const char *msg_no_nl)
 {
        if (state.hs_len > 0) {
+               ensure_copy_no_nl(state.header_str_no_nl,
+                                 sizeof(state.header_str_no_nl),
+                                 state.header_str,
+                                 state.hs_len);
                sd_journal_send("MESSAGE=%s",
                                state.header_str_no_nl,
                                "PRIORITY=%d",
@@ -337,6 +362,10 @@ static void debug_lttng_log(int msg_level,
                            const char *msg_no_nl)
 {
        if (state.hs_len > 0) {
+               ensure_copy_no_nl(state.header_str_no_nl,
+                                 sizeof(state.header_str_no_nl),
+                                 state.header_str,
+                                 state.hs_len);
                tracef(state.header_str_no_nl);
        }
        tracef(msg_no_nl);
@@ -374,6 +403,10 @@ static void debug_gpfs_log(int msg_level,
                           const char *msg_no_nl)
 {
        if (state.hs_len > 0) {
+               ensure_copy_no_nl(state.header_str_no_nl,
+                                 sizeof(state.header_str_no_nl),
+                                 state.header_str,
+                                 state.hs_len);
                gpfswrap_add_trace(msg_level, state.header_str_no_nl);
        }
        gpfswrap_add_trace(msg_level, msg_no_nl);
@@ -1738,10 +1771,7 @@ full:
                state.hs_len = sizeof(state.header_str) - 1;
        }
 
-       copy_no_nl(state.header_str_no_nl,
-                  sizeof(state.header_str_no_nl),
-                  state.header_str,
-                  state.hs_len);
+       state.header_str_no_nl[0] = '\0';
 
        errno = old_errno;
        return( true );