[PATCH 1/4] trace-cmd library: Add internal database for trace buffers

["Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>]

The new list with trace buffers information is added in the output
handler, and internal APIs to work with that list. Storing various trace
buffers information in the handler hides the complexity of this
logic inside the library and simplifies possible extensions in the
future.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 .../include/private/trace-cmd-private.h       |  2 +
 lib/trace-cmd/trace-output.c                  | 58 ++++++++++++++++++-
 2 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index 167f3804..75680d73 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -292,6 +292,8 @@ tracecmd_add_option_v(struct tracecmd_output *handle,
 
 struct tracecmd_option *tracecmd_add_buffer_option(struct tracecmd_output *handle,
 						   const char *name, int cpus);
+int tracecmd_add_buffer_info(struct tracecmd_output *handle, const char *name, int cpus);
+int tracecmd_write_buffer_info(struct tracecmd_output *handle);
 
 int tracecmd_write_cpus(struct tracecmd_output *handle, int cpus);
 int tracecmd_write_cmdlines(struct tracecmd_output *handle);
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 27f296dd..f0f6aeed 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -39,6 +39,14 @@ struct tracecmd_option {
 	struct list_head list;
 };
 
+struct tracecmd_buffer {
+	int				cpus;
+	void				*name;
+	tsize_t				offset;
+	struct tracecmd_option		*option;
+	struct list_head		list;
+};
+
 enum {
 	OUTPUT_FL_SEND_META	= (1 << 0),
 };
@@ -58,6 +66,7 @@ struct tracecmd_output {
 	bool			big_endian;
 
 	struct list_head	options;
+	struct list_head	buffers;
 	struct tracecmd_msg_handle *msg_handle;
 	char			*trace_clock;
 };
@@ -140,6 +149,7 @@ bool tracecmd_get_quiet(struct tracecmd_output *handle)
 void tracecmd_output_free(struct tracecmd_output *handle)
 {
 	struct tracecmd_option *option;
+	struct tracecmd_buffer *buffer;
 
 	if (!handle)
 		return;
@@ -150,6 +160,13 @@ void tracecmd_output_free(struct tracecmd_output *handle)
 	if (handle->pevent)
 		tep_unref(handle->pevent);
 
+	while (!list_empty(&handle->buffers)) {
+		buffer = container_of(handle->buffers.next,
+				      struct tracecmd_buffer, list);
+		list_del(&buffer->list);
+		free(buffer->name);
+		free(buffer);
+	}
 	while (!list_empty(&handle->options)) {
 		option = container_of(handle->options.next,
 				      struct tracecmd_option, list);
@@ -157,6 +174,7 @@ void tracecmd_output_free(struct tracecmd_output *handle)
 		free(option->data);
 		free(option);
 	}
+
 	free(handle->trace_clock);
 	free(handle);
 }
@@ -907,6 +925,7 @@ struct tracecmd_output *tracecmd_output_allocate(int fd)
 	handle->big_endian = tracecmd_host_bigendian();
 
 	list_head_init(&handle->options);
+	list_head_init(&handle->buffers);
 
 	handle->file_state = TRACECMD_FILE_ALLOCATED;
 
@@ -1323,7 +1342,7 @@ tracecmd_add_buffer_option(struct tracecmd_output *handle, const char *name,
 	char *buf;
 	int size = 8 + strlen(name) + 1;
 
-	buf = malloc(size);
+	buf = calloc(1, size);
 	if (!buf) {
 		tracecmd_warning("Failed to malloc buffer");
 		return NULL;
@@ -1345,6 +1364,38 @@ tracecmd_add_buffer_option(struct tracecmd_output *handle, const char *name,
 	return option;
 }
 
+int tracecmd_add_buffer_info(struct tracecmd_output *handle, const char *name, int cpus)
+{
+	struct tracecmd_buffer *buf;
+
+	buf = calloc(1, sizeof(struct tracecmd_buffer));
+	if (!buf)
+		return -1;
+	buf->name = strdup(name);
+	buf->cpus = cpus;
+	if (!buf->name) {
+		free(buf);
+		return -1;
+	}
+	list_add_tail(&buf->list, &handle->buffers);
+	return 0;
+}
+
+int tracecmd_write_buffer_info(struct tracecmd_output *handle)
+{
+	struct tracecmd_option *option;
+	struct tracecmd_buffer *buf;
+
+	list_for_each_entry(buf, &handle->buffers, list) {
+		option = tracecmd_add_buffer_option(handle, buf->name, buf->cpus);
+		if (!option)
+			return -1;
+		buf->option = option;
+	}
+
+	return 0;
+}
+
 int tracecmd_write_cmdlines(struct tracecmd_output *handle)
 {
 	int ret;
@@ -1580,7 +1631,9 @@ int tracecmd_append_cpu_data(struct tracecmd_output *handle,
 	ret = tracecmd_write_cpus(handle, cpus);
 	if (ret)
 		return ret;
-
+	ret = tracecmd_write_buffer_info(handle);
+	if (ret)
+		return ret;
 	ret = tracecmd_write_options(handle);
 	if (ret)
 		return ret;
@@ -1658,6 +1711,7 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd)
 	handle->file_version = tracecmd_get_in_file_version(ihandle);
 	handle->options_start = tracecmd_get_options_offset(ihandle);
 	list_head_init(&handle->options);
+	list_head_init(&handle->buffers);
 
 	tracecmd_close(ihandle);
 
-- 
2.31.1