From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Adds an API to read a "hist" file of a trace event and create a list of
tracefs_hist_data descriptors for every histogram that exists in the
"hist" file.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 7 ++++
src/tracefs-hist-data.c | 74 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 81 insertions(+)
diff --git a/include/tracefs.h b/include/tracefs.h
index 6bd40d72cb25..f1e4ffa0d65f 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -418,7 +418,14 @@ struct tracefs_hist_data;
struct tracefs_hist_data *tracefs_hist_data_parse(const char *buffer,
const char **next_buffer,
char **err);
+
+struct tracefs_hist_data **tracefs_hist_data_read(struct tracefs_instance *instance,
+ const char *system,
+ const char *event,
+ char **err);
+
void tracefs_hist_data_free(struct tracefs_hist_data *hdata);
+void tracefs_hist_data_free_list(struct tracefs_hist_data **hdata_list);
struct tracefs_synth;
diff --git a/src/tracefs-hist-data.c b/src/tracefs-hist-data.c
index c7e110559ee8..ab1ae824f59b 100644
--- a/src/tracefs-hist-data.c
+++ b/src/tracefs-hist-data.c
@@ -718,6 +718,24 @@ void tracefs_hist_data_free(struct tracefs_hist_data *hdata)
free(hdata);
}
+/**
+ * tracefs_hist_data_free_list - frees a list of created hist data descriptors
+ * @hdata_list: The tracefs_hist_data descriptor list to free.
+ *
+ * Frees the data allocated by tracefs_hist_data_read().
+ */
+void tracefs_hist_data_free_list(struct tracefs_hist_data **hdata_list)
+{
+ int i;
+
+ if (!hdata_list)
+ return;
+
+ for (i = 0; hdata_list[i]; i++)
+ tracefs_hist_data_free(hdata_list[i]);
+ free(hdata_list);
+}
+
/* Used for debugging in gdb */
static void breakpoint(char *text)
{
@@ -1019,3 +1037,59 @@ tracefs_hist_data_parse(const char *buffer, const char **next_buffer, char **err
tracefs_hist_data_free(hdata);
return NULL;
}
+
+/**
+ * tracefs_hist_data_read - Reads and parses the trace event "hist" file
+ * @instance: The instance the trace event is in (NULL for top level)
+ * @system: The system of the @event (NULL to pick first event)
+ * @event: The trace event name to read the hist file from
+ * @err: On parsing errors, @err will be set to a message explaining what failed.
+ *
+ * Reads the content of a trace @event hist file and parses it.
+ *
+ * Returns an array of tracefs_hist_data descriptors, as a hist file
+ * may contain more than one histogram. Must be freed with
+ * tracefs_hist_data_free_list().
+ *
+ * Returns NULL on error, and if there was a parsing error, @err will contain
+ * a message explaining what failed.
+ */
+struct tracefs_hist_data **
+tracefs_hist_data_read(struct tracefs_instance *instance,
+ const char *system, const char *event, char **err)
+{
+ struct tracefs_hist_data **tmp, **hdata_list = NULL;
+ const char *buffer;
+ char *content;
+ int cnt = 0;
+
+ if (err)
+ *err = NULL;
+
+ content = tracefs_event_file_read(instance, system, event, "hist", NULL);
+ if (!content)
+ return NULL;
+
+ buffer = content;
+ do {
+ tmp = realloc(hdata_list, sizeof(*tmp) * (cnt + 2));
+ if (!tmp)
+ goto error;
+ tmp[cnt + 1] = NULL;
+ tmp[cnt] = tracefs_hist_data_parse(buffer, &buffer, err);
+ if (!tmp[cnt])
+ goto error;
+ hdata_list = tmp;
+ if (buffer)
+ cnt++;
+ } while (buffer);
+
+ free(content);
+ return hdata_list;
+
+ error:
+ free(content);
+ tracefs_hist_data_free_list(hdata_list);
+ return NULL;
+}
+
--
2.30.2
