trace: Specify trace file name
Allow users to specify a file for trace-outputs at configuration.
Also, allow trace files to be annotated by <pid> so each qemu instance has
unique traces.
The trace file name can be passed as a config option:
--trace-file=/path/to/file
(Default: trace )
At runtime, the pid of the qemu process is appended to the filename so
that mutiple qemu instances do not have overlapping logs.
Eg : trace-1234 for qemu launched with pid 1234.
I have yet to test this on windows. getpid() is used at many places
in code(including vnc.c), so I'm hoping this would be okay too.
Edited-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/configure b/configure
index 5afb3b5..234e75b 100755
--- a/configure
+++ b/configure
@@ -318,6 +318,7 @@
user_pie="no"
zero_malloc=""
trace_backend="nop"
+trace_file="trace"
# OS specific
if check_define __linux__ ; then
@@ -522,6 +523,8 @@
;;
--trace-backend=*) trace_backend="$optarg"
;;
+ --trace-file=*) trace_file="$optarg"
+ ;;
--enable-gprof) gprof="yes"
;;
--static)
@@ -901,6 +904,8 @@
echo " --disable-vhost-net disable vhost-net acceleration support"
echo " --enable-vhost-net enable vhost-net acceleration support"
echo " --trace-backend=B Trace backend nop simple"
+echo " --trace-file=NAME Full PATH,NAME of file to store traces"
+echo " Default:trace-<pid>"
echo ""
echo "NOTE: The object files are built at the place where configure is launched"
exit 1
@@ -2206,6 +2211,7 @@
echo "uuid support $uuid"
echo "vhost-net support $vhost_net"
echo "Trace backend $trace_backend"
+echo "Trace output file $trace_file-<pid>"
if test $sdl_too_old = "yes"; then
echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -2471,6 +2477,12 @@
if test "$trace_backend" = "simple"; then
echo "CONFIG_SIMPLE_TRACE=y" >> $config_host_mak
fi
+# Set the appropriate trace file.
+if test "$trace_backend" = "simple"; then
+ trace_file="\"$trace_file-%u\""
+fi
+echo "CONFIG_TRACE_FILE=$trace_file" >> $config_host_mak
+
echo "TOOLS=$tools" >> $config_host_mak
echo "ROMS=$roms" >> $config_host_mak
echo "MAKE=$make" >> $config_host_mak
diff --git a/simpletrace.c b/simpletrace.c
index 688959a..97045a6 100644
--- a/simpletrace.c
+++ b/simpletrace.c
@@ -54,13 +54,26 @@
return fwrite(&header, sizeof header, 1, fp) == 1;
}
+static bool open_trace_file(void)
+{
+ char *filename;
+
+ if (asprintf(&filename, CONFIG_TRACE_FILE, getpid()) < 0) {
+ return false;
+ }
+
+ trace_fp = fopen(filename, "w");
+ free(filename);
+ if (!trace_fp) {
+ return false;
+ }
+ return write_header(trace_fp);
+}
+
static void flush_trace_buffer(void)
{
if (!trace_fp) {
- trace_fp = fopen("trace.log", "w");
- if (trace_fp) {
- write_header(trace_fp);
- }
+ open_trace_file();
}
if (trace_fp) {
size_t unused; /* for when fwrite(3) is declared warn_unused_result */
