[PATCH v7 07/25] trace-cmd library: Add multiple options sections in trace file version 7

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

Introduced chain of options sections in trace file version 7. Extended
the "DONE" option to hold the offset into the file to the next options
section.
Format of trace file version 7 is extended with a new mandatory field
after the compression algorithm header:
 <8 bytes>, unsigned long long integer - offset into the trace file
where the first options section is located. This allows to place this
section anywhere in the file. As all other sections have corresponding
options, describing their offsets into the trace file, this change makes
the structure of trace file version 7 flexible.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 lib/trace-cmd/trace-output.c | 103 ++++++++++++++++++++++++++++++++---
 1 file changed, 96 insertions(+), 7 deletions(-)

diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index aa55aad7..6e07fece 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -64,7 +64,7 @@ struct tracecmd_output {
 	unsigned long		file_version;
 	unsigned long		strings_p;
 	unsigned long		strings_offs;
-	size_t			options_start;
+	tsize_t			options_start;
 	bool			big_endian;
 
 	struct list_head	options;
@@ -89,6 +89,7 @@ struct list_event_system {
 
 #define HAS_SECTIONS(H) ((H)->file_version >= FILE_VERSION_SECTIONS)
 
+static int write_options_v7(struct tracecmd_output *handle);
 static int save_string_section(struct tracecmd_output *handle);
 
 static stsize_t
@@ -218,6 +219,9 @@ void tracecmd_output_close(struct tracecmd_output *handle)
 		return;
 
 	if (handle->file_version >= FILE_VERSION_SECTIONS) {
+		/* write any unsaved options at the end of trace files with sections */
+		write_options_v7(handle);
+
 		/* write strings section */
 		save_string_section(handle);
 	}
@@ -1295,6 +1299,7 @@ int tracecmd_output_set_version(struct tracecmd_output *handle, int file_version
  */
 static int output_write_init(struct tracecmd_output *handle)
 {
+	unsigned long long offset;
 	char buf[BUFSIZ];
 	int endian4;
 
@@ -1328,6 +1333,14 @@ static int output_write_init(struct tracecmd_output *handle)
 	endian4 = convert_endian_4(handle, handle->page_size);
 	if (do_write_check(handle, &endian4, 4))
 		return -1;
+	if (HAS_SECTIONS(handle)) {
+		/* Write 0 as options offset and save its location */
+		offset = 0;
+		handle->options_start = do_lseek(handle, 0, SEEK_CUR);
+		if (do_write_check(handle, &offset, 8))
+			return -1;
+	}
+
 	handle->file_state = TRACECMD_FILE_INIT;
 	return 0;
 }
@@ -1396,7 +1409,7 @@ tracecmd_add_option_v(struct tracecmd_output *handle,
 	 * We can only add options before tracing data were written.
 	 * This may change in the future.
 	 */
-	if (handle->file_state > TRACECMD_FILE_OPTIONS)
+	if (!HAS_SECTIONS(handle) && handle->file_state > TRACECMD_FILE_OPTIONS)
 		return NULL;
 
 	for (i = 0; i < count; i++)
@@ -1409,8 +1422,7 @@ tracecmd_add_option_v(struct tracecmd_output *handle,
 			return NULL;
 		}
 	}
-
-	option = malloc(sizeof(*option));
+	option = calloc(1, sizeof(*option));
 	if (!option) {
 		tracecmd_warning("Could not allocate space for option");
 		free(data);
@@ -1473,7 +1485,7 @@ int tracecmd_write_cpus(struct tracecmd_output *handle, int cpus)
 	return 0;
 }
 
-int tracecmd_write_options(struct tracecmd_output *handle)
+static int write_options_v6(struct tracecmd_output *handle)
 {
 	struct tracecmd_option *options;
 	unsigned short option;
@@ -1491,7 +1503,7 @@ int tracecmd_write_options(struct tracecmd_output *handle)
 
 	if (do_write_check(handle, "options  ", 10))
 		return -1;
-
+	handle->options_start = do_lseek(handle, 0, SEEK_CUR);
 	list_for_each_entry(options, &handle->options, list) {
 		endian2 = convert_endian_2(handle, options->id);
 		if (do_write_check(handle, &endian2, 2))
@@ -1515,6 +1527,70 @@ int tracecmd_write_options(struct tracecmd_output *handle)
 		return -1;
 
 	handle->file_state = TRACECMD_FILE_OPTIONS;
+	return 0;
+}
+
+static int write_options_v7(struct tracecmd_output *handle)
+{
+	struct tracecmd_option *options;
+	unsigned long long endian8;
+	unsigned short endian2;
+	unsigned int endian4;
+	bool new = false;
+	tsize_t offset;
+
+	/* Check if there are unsaved options */
+	list_for_each_entry(options, &handle->options, list) {
+		if (!options->offset) {
+			new = true;
+			break;
+		}
+	}
+
+	if (!new)
+		return 0;
+	offset = do_lseek(handle, 0, SEEK_CUR);
+	/* Append to the previous options section, if any */
+	if (handle->options_start) {
+		if (do_lseek(handle, handle->options_start, SEEK_SET) == (off64_t)-1)
+			return -1;
+		endian8 = convert_endian_8(handle, offset);
+		if (do_write_check(handle, &endian8, 8))
+			return -1;
+		if (do_lseek(handle, offset, SEEK_SET) == (off_t)-1)
+			return -1;
+	}
+	offset = out_write_section_header(handle, TRACECMD_OPTION_DONE, "options", 0, false);
+	if (offset == (off_t)-1)
+		return -1;
+	list_for_each_entry(options, &handle->options, list) {
+		/* Option is already saved, skip it */
+		if (options->offset)
+			continue;
+		endian2 = convert_endian_2(handle, options->id);
+		if (do_write_check(handle, &endian2, 2))
+			return -1;
+		endian4 = convert_endian_4(handle, options->size);
+		if (do_write_check(handle, &endian4, 4))
+			return -1;
+		/* Save the data location */
+		options->offset = do_lseek(handle, 0, SEEK_CUR);
+		if (do_write_check(handle, options->data, options->size))
+			return -1;
+	}
+
+	endian2 = convert_endian_2(handle, TRACECMD_OPTION_DONE);
+	if (do_write_check(handle, &endian2, 2))
+		return -1;
+	endian4 = convert_endian_4(handle, 8);
+	if (do_write_check(handle, &endian4, 4))
+		return -1;
+	endian8 = 0;
+	handle->options_start = do_lseek(handle, 0, SEEK_CUR);
+	if (do_write_check(handle, &endian8, 8))
+		return -1;
+	if (out_update_section_header(handle, offset))
+		return -1;
 
 	return 0;
 }
@@ -1527,8 +1603,14 @@ int tracecmd_write_meta_strings(struct tracecmd_output *handle)
 	return save_string_section(handle);
 }
 
+int tracecmd_write_options(struct tracecmd_output *handle)
+{
+	if (!HAS_SECTIONS(handle))
+		return write_options_v6(handle);
+	return write_options_v7(handle);
+}
 
-int tracecmd_append_options(struct tracecmd_output *handle)
+static int append_options_v6(struct tracecmd_output *handle)
 {
 	struct tracecmd_option *options;
 	unsigned short option;
@@ -1579,6 +1661,13 @@ int tracecmd_append_options(struct tracecmd_output *handle)
 	return 0;
 }
 
+int tracecmd_append_options(struct tracecmd_output *handle)
+{
+	if (!HAS_SECTIONS(handle))
+		return append_options_v6(handle);
+	return write_options_v7(handle);
+}
+
 static struct tracecmd_option *
 add_buffer_option(struct tracecmd_output *handle, const char *name, int cpus)
 {
-- 
2.33.1