From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Add the following functions:
tracefs_event_get_file() to easily put together a path to a file in the
event directory.
tracefs_event_file_read() to easily read the content from a file in the
event directory.
tracefs_event_file_write() to easily write content to a file in the
event directory.
tracefs_event_file_append() to easily append content to a file in the
event directory.
tracefs_event_file_clear() to easily clear the content of a file in the
event directory.
tracefs_event_file_exists() to easily know if a file exists in the
event directory.
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/tracefs.h | 19 +++++
src/tracefs-events.c | 182 +++++++++++++++++++++++++++++++++++++++++++
2 files changed, 201 insertions(+)
diff --git a/include/tracefs.h b/include/tracefs.h
index 6b9a76c4c40a..afbfd4eb01d6 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -102,6 +102,25 @@ int tracefs_iterate_raw_events(struct tep_handle *tep,
void *callback_context);
void tracefs_iterate_stop(struct tracefs_instance *instance);
+char *tracefs_event_get_file(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file);
+char *tracefs_event_file_read(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, int *psize);
+int tracefs_event_file_write(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, const char *str);
+int tracefs_event_file_append(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, const char *str);
+int tracefs_event_file_clear(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file);
+bool tracefs_event_file_exists(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file);
+
char **tracefs_tracers(const char *tracing_dir);
struct tep_handle *tracefs_local_events(const char *tracing_dir);
diff --git a/src/tracefs-events.c b/src/tracefs-events.c
index 4bfd8e451ef5..7febc2a0f24d 100644
--- a/src/tracefs-events.c
+++ b/src/tracefs-events.c
@@ -302,6 +302,188 @@ __hidden char *trace_append_file(const char *dir, const char *name)
return ret < 0 ? NULL : file;
}
+static int event_file(char **path, const char *system,
+ const char *event, const char *file)
+{
+ if (!system || !event || !file)
+ return -1;
+
+ return asprintf(path, "events/%s/%s/%s",
+ system, event, file);
+}
+
+/**
+ * tracefs_event_get_file - return a file in an event directory
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ *
+ * Returns a path to a file in the event director.
+ * or NULL on error. The path returned must be freed with
+ * tracefs_put_tracing_file().
+ */
+char *tracefs_event_get_file(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file)
+{
+ char *instance_path;
+ char *path;
+ int ret;
+
+ ret = event_file(&path, system, event, file);
+ if (ret < 0)
+ return NULL;
+
+ instance_path = tracefs_instance_get_file(instance, path);
+ free(path);
+
+ return instance_path;
+}
+
+/**
+ * tracefs_event_file_read - read the content from an event file
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ * @psize: the size of the content read.
+ *
+ * Reads the content of the event file that is passed via the
+ * arguments and returns the content.
+ *
+ * Return a string containing the content of the file or NULL
+ * on error. The string returned must be freed with free().
+ */
+char *tracefs_event_file_read(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, int *psize)
+{
+ char *content;
+ char *path;
+ int ret;
+
+ ret = event_file(&path, system, event, file);
+ if (ret < 0)
+ return NULL;
+
+ content = tracefs_instance_file_read(instance, path, psize);
+ free(path);
+ return content;
+}
+
+/**
+ * tracefs_event_file_write - write to an event file
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ * @str: The string to write into the file
+ *
+ * Writes the content of @str to a file in the instance directory.
+ * The content of the file will be overwritten by @str.
+ *
+ * Return 0 on success, and -1 on error.
+ */
+int tracefs_event_file_write(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, const char *str)
+{
+ char *path;
+ int ret;
+
+ ret = event_file(&path, system, event, file);
+ if (ret < 0)
+ return -1;
+
+ ret = tracefs_instance_file_write(instance, path, str);
+ free(path);
+ return ret;
+}
+
+/**
+ * tracefs_event_file_append - write to an event file
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ * @str: The string to write into the file
+ *
+ * Writes the content of @str to a file in the instance directory.
+ * The content of @str will be appended to the content of the file.
+ * The current content should not be lost.
+ *
+ * Return 0 on success, and -1 on error.
+ */
+int tracefs_event_file_append(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file, const char *str)
+{
+ char *path;
+ int ret;
+
+ ret = event_file(&path, system, event, file);
+ if (ret < 0)
+ return -1;
+
+ ret = tracefs_instance_file_append(instance, path, str);
+ free(path);
+ return ret;
+}
+
+/**
+ * tracefs_event_file_clear - clear an event file
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ *
+ * Clears the content of the event file. That is, it is opened
+ * with O_TRUNC and then closed.
+ *
+ * Return 0 on success, and -1 on error.
+ */
+int tracefs_event_file_clear(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file)
+{
+ char *path;
+ int ret;
+
+ ret = event_file(&path, system, event, file);
+ if (ret < 0)
+ return -1;
+
+ ret = tracefs_instance_file_clear(instance, path);
+ free(path);
+ return ret;
+}
+
+/**
+ * tracefs_event_file_exits - test if a file exists
+ * @instance: The instance the event is in (NULL for top level)
+ * @system: The system name that the event file is in
+ * @event: The event name of the event
+ * @file: The name of the file in the event directory.
+ *
+ * Return true if the file exists, false if it odes not or
+ * an error occurred.
+ */
+bool tracefs_event_file_exists(struct tracefs_instance *instance,
+ const char *system, const char *event,
+ const char *file)
+{
+ char *path;
+ bool ret;
+
+ if (event_file(&path, system, event, file) < 0)
+ return false;
+
+ ret = tracefs_file_exists(instance, path);
+ free(path);
+ return ret;
+}
+
/**
* tracefs_event_systems - return list of systems for tracing
* @tracing_dir: directory holding the "events" directory
--
2.30.2
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