trace: add syslog tracing backend

This patch adds a tracing backend which sends output using syslog().
The syslog backend is limited to POSIX compliant systems.

openlog() is called with facility set to LOG_DAEMON, with the LOG_PID
option. Trace events are logged at level LOG_INFO.

Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Message-id: 1470318254-29989-1-git-send-email-paul.durrant@citrix.com
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/configure b/configure
index 4b808f9d17..5a9bda18b5 100755
--- a/configure
+++ b/configure
@@ -4192,6 +4192,18 @@ if compile_prog "" "" ; then
 fi
 
 ##########################################
+# check if we have posix_syslog
+
+posix_syslog=no
+cat > $TMPC << EOF
+#include <syslog.h>
+int main(void) { openlog("qemu", LOG_PID, LOG_DAEMON); syslog(LOG_INFO, "configure"); return 0; }
+EOF
+if compile_prog "" "" ; then
+    posix_syslog=yes
+fi
+
+##########################################
 # check if trace backend exists
 
 $python "$source_path/scripts/tracetool.py" "--backends=$trace_backends" --check-backends  > /dev/null 2> /dev/null
@@ -5468,6 +5480,13 @@ if have_backend "ftrace"; then
     feature_not_found "ftrace(trace backend)" "ftrace requires Linux"
   fi
 fi
+if have_backend "syslog"; then
+  if test "$posix_syslog" = "yes" ; then
+    echo "CONFIG_TRACE_SYSLOG=y" >> $config_host_mak
+  else
+    feature_not_found "syslog(trace backend)" "syslog not available"
+  fi
+fi
 echo "CONFIG_TRACE_FILE=$trace_file" >> $config_host_mak
 
 if test "$rdma" = "yes" ; then