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authorMarkus Armbruster <armbru@redhat.com>2020-05-27 08:56:13 +0200
committerStefan Hajnoczi <stefanha@redhat.com>2020-06-24 11:21:00 +0100
commitdb25d56c014aa1a96319c663e0a60346a223b31e (patch)
tree71eba884363be7e000b42695fb7b20058f3bf327 /trace
parentf892b494fafd39660679c1c4ef1dbe711a73df45 (diff)
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trace/simple: Fix unauthorized enable
st_set_trace_file() accidentally enables tracing. It's called unconditionally during startup, which is why QEMU built with the simple trace backend always writes a trace file "trace-$PID". This has been broken for quite a while. I didn't track down the exact commit. Fix st_set_trace_file() to restore the state. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Message-id: 20200527065613.25322-1-armbru@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'trace')
-rw-r--r--trace/simple.c20
-rw-r--r--trace/simple.h2
2 files changed, 15 insertions, 7 deletions
diff --git a/trace/simple.c b/trace/simple.c
index fc7106e..9cd2ed1 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -302,10 +302,17 @@ static int st_write_event_mapping(void)
return 0;
}
-void st_set_trace_file_enabled(bool enable)
+/**
+ * Enable / disable tracing, return whether it was enabled.
+ *
+ * @enable: enable if %true, else disable.
+ */
+bool st_set_trace_file_enabled(bool enable)
{
+ bool was_enabled = trace_fp;
+
if (enable == !!trace_fp) {
- return; /* no change */
+ return was_enabled; /* no change */
}
/* Halt trace writeout */
@@ -323,14 +330,14 @@ void st_set_trace_file_enabled(bool enable)
trace_fp = fopen(trace_file_name, "wb");
if (!trace_fp) {
- return;
+ return was_enabled;
}
if (fwrite(&header, sizeof header, 1, trace_fp) != 1 ||
st_write_event_mapping() < 0) {
fclose(trace_fp);
trace_fp = NULL;
- return;
+ return was_enabled;
}
/* Resume trace writeout */
@@ -340,6 +347,7 @@ void st_set_trace_file_enabled(bool enable)
fclose(trace_fp);
trace_fp = NULL;
}
+ return was_enabled;
}
/**
@@ -350,7 +358,7 @@ void st_set_trace_file_enabled(bool enable)
*/
void st_set_trace_file(const char *file)
{
- st_set_trace_file_enabled(false);
+ bool saved_enable = st_set_trace_file_enabled(false);
g_free(trace_file_name);
@@ -361,7 +369,7 @@ void st_set_trace_file(const char *file)
trace_file_name = g_strdup_printf("%s", file);
}
- st_set_trace_file_enabled(true);
+ st_set_trace_file_enabled(saved_enable);
}
void st_print_trace_file_status(void)
diff --git a/trace/simple.h b/trace/simple.h
index 5771a06..26ccbc8 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -12,7 +12,7 @@
#define TRACE_SIMPLE_H
void st_print_trace_file_status(void);
-void st_set_trace_file_enabled(bool enable);
+bool st_set_trace_file_enabled(bool enable);
void st_set_trace_file(const char *file);
bool st_init(void);
void st_flush_trace_buffer(void);