[PATCH v2 22/87] trace-cmd library: Write header before file sections

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

Headers are added before these file secrtions, in trace
file version 7:
 - ftrace events format
 - format of recorded events
 - information of the mapping of function addresses to the function names
 - trace_printk() format strings
 - information of the mapping a PID to a process name

New options are defined for each of these sections, holding
the section's offset into the trace file.

Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
---
 .../include/private/trace-cmd-private.h       |  6 ++
 lib/trace-cmd/trace-output.c                  | 69 +++++++++++++++++++
 2 files changed, 75 insertions(+)

diff --git a/lib/trace-cmd/include/private/trace-cmd-private.h b/lib/trace-cmd/include/private/trace-cmd-private.h
index 77948fbb..b193d6de 100644
--- a/lib/trace-cmd/include/private/trace-cmd-private.h
+++ b/lib/trace-cmd/include/private/trace-cmd-private.h
@@ -135,6 +135,12 @@ enum {
 	TRACECMD_OPTION_TIME_SHIFT,
 	TRACECMD_OPTION_GUEST,
 	TRACECMD_OPTION_TSC2NSEC,
+	TRACECMD_OPTION_HEADER_INFO,
+	TRACECMD_OPTION_FTRACE_EVENTS,
+	TRACECMD_OPTION_EVENT_FORMATS,
+	TRACECMD_OPTION_KALLSYMS,
+	TRACECMD_OPTION_PRINTK,
+	TRACECMD_OPTION_CMDLINES,
 	TRACECMD_OPTION_MAX,
 };
 
diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
index 74192ea2..a5c11eba 100644
--- a/lib/trace-cmd/trace-output.c
+++ b/lib/trace-cmd/trace-output.c
@@ -438,8 +438,10 @@ __hidden int out_update_section_header(struct tracecmd_output *handle, unsigned
 
 static int read_header_files(struct tracecmd_output *handle, bool compress)
 {
+	enum tracecmd_section_flags flags = 0;
 	tsize_t size, check_size, endian8;
 	struct stat st;
+	tsize_t offset;
 	char *path;
 	int fd = -1;
 	int ret;
@@ -454,6 +456,13 @@ static int read_header_files(struct tracecmd_output *handle, bool compress)
 	if (!path)
 		return -1;
 
+	if (compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_HEADER_INFO,
+					  "headers", flags, true);
+	if (offset == (off_t)-1)
+		return -1;
+
 	if (compress)
 		out_compression_start(handle);
 	ret = stat(path, &st);
@@ -469,6 +478,8 @@ static int read_header_files(struct tracecmd_output *handle, bool compress)
 			goto out_close;
 		if (do_write_check(handle, &size, 8))
 			goto out_close;
+		if (out_update_section_header(handle, offset))
+			goto out_close;
 		if (compress && out_compression_end(handle))
 			goto out_close;
 		return 0;
@@ -523,6 +534,8 @@ static int read_header_files(struct tracecmd_output *handle, bool compress)
 	put_tracing_file(path);
 	if (compress && out_compression_end(handle))
 		goto out_close;
+	if (out_update_section_header(handle, offset))
+		goto out_close;
 	handle->file_state = TRACECMD_FILE_HEADERS;
 
 	return 0;
@@ -759,8 +772,10 @@ create_event_list_item(struct tracecmd_output *handle,
 
 static int read_ftrace_files(struct tracecmd_output *handle, bool compress)
 {
+	enum tracecmd_section_flags flags = 0;
 	struct list_event_system *systems = NULL;
 	struct tracecmd_event_list list = { .glob = "ftrace/*" };
+	tsize_t offset;
 	int ret;
 
 	if (!check_out_state(handle, TRACECMD_FILE_FTRACE_EVENTS)) {
@@ -769,6 +784,13 @@ static int read_ftrace_files(struct tracecmd_output *handle, bool compress)
 		return -1;
 	}
 
+	if (compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_FTRACE_EVENTS,
+					  "ftrace events", flags, true);
+	if (offset == (off_t)-1)
+		return -1;
+
 	create_event_list_item(handle, &systems, &list);
 	if (compress)
 		out_compression_start(handle);
@@ -780,6 +802,10 @@ static int read_ftrace_files(struct tracecmd_output *handle, bool compress)
 			out_compression_reset(handle);
 	}
 	free_list_events(systems);
+	if (ret)
+		return ret;
+	if (out_update_section_header(handle, offset))
+		return -1;
 
 	handle->file_state = TRACECMD_FILE_FTRACE_EVENTS;
 
@@ -802,11 +828,13 @@ create_event_list(struct tracecmd_output *handle,
 static int read_event_files(struct tracecmd_output *handle,
 			    struct tracecmd_event_list *event_list, bool compress)
 {
+	enum tracecmd_section_flags flags = 0;
 	struct list_event_system *systems;
 	struct list_event_system *slist;
 	struct tracecmd_event_list *list;
 	struct tracecmd_event_list all_events = { .glob = "*/*" };
 	int count = 0;
+	tsize_t offset;
 	int endian4;
 	int ret;
 
@@ -815,6 +843,13 @@ static int read_event_files(struct tracecmd_output *handle,
 				 handle->file_state);
 		return -1;
 	}
+
+	if (compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_EVENT_FORMATS,
+					  "events format", flags, true);
+	if (offset == (off64_t)-1)
+		return -1;
 	/*
 	 * If any of the list is the special keyword "all" then
 	 * just do all files.
@@ -854,6 +889,8 @@ static int read_event_files(struct tracecmd_output *handle,
 		if (ret)
 			goto out_free;
 	}
+	ret = out_update_section_header(handle, offset);
+
  out_free:
 	if (!ret)
 		handle->file_state = TRACECMD_FILE_ALL_EVENTS;
@@ -907,8 +944,10 @@ err:
 
 static int read_proc_kallsyms(struct tracecmd_output *handle, bool compress)
 {
+	enum tracecmd_section_flags flags = 0;
 	unsigned int size, check_size, endian4;
 	const char *path = "/proc/kallsyms";
+	tsize_t offset;
 	struct stat st;
 	int ret;
 
@@ -921,6 +960,13 @@ static int read_proc_kallsyms(struct tracecmd_output *handle, bool compress)
 	if (handle->kallsyms)
 		path = handle->kallsyms;
 
+	if (compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_KALLSYMS,
+					  "kallsyms", flags, true);
+	if (offset == (off64_t)-1)
+		return -1;
+
 	if (compress)
 		out_compression_start(handle);
 	ret = stat(path, &st);
@@ -953,6 +999,7 @@ static int read_proc_kallsyms(struct tracecmd_output *handle, bool compress)
 		if (ret)
 			goto out;
 	}
+	ret = out_update_section_header(handle, offset);
 out:
 	if (!ret)
 		handle->file_state = TRACECMD_FILE_KALLSYMS;
@@ -963,7 +1010,9 @@ out:
 
 static int read_ftrace_printk(struct tracecmd_output *handle, bool compress)
 {
+	enum tracecmd_section_flags flags = 0;
 	unsigned int size, check_size, endian4;
+	tsize_t offset;
 	struct stat st;
 	char *path;
 	int ret;
@@ -978,6 +1027,12 @@ static int read_ftrace_printk(struct tracecmd_output *handle, bool compress)
 	if (!path)
 		return -1;
 
+	if (compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_PRINTK, "printk", flags, true);
+	if (offset == (off64_t)-1)
+		return -1;
+
 	if (compress)
 		out_compression_start(handle);
 	ret = stat(path, &st);
@@ -1004,6 +1059,8 @@ static int read_ftrace_printk(struct tracecmd_output *handle, bool compress)
 	put_tracing_file(path);
 	if (compress && out_compression_end(handle))
 		return -1;
+	if (out_update_section_header(handle, offset))
+		return -1;
 	handle->file_state = TRACECMD_FILE_PRINTK;
 	return 0;
  fail:
@@ -1636,6 +1693,8 @@ tracecmd_add_buffer_option(struct tracecmd_output *handle, const char *name,
 
 int tracecmd_write_cmdlines(struct tracecmd_output *handle)
 {
+	enum tracecmd_section_flags flags = 0;
+	tsize_t offset;
 	int ret;
 
 	if (!check_out_state(handle, TRACECMD_FILE_CMD_LINES)) {
@@ -1644,6 +1703,13 @@ int tracecmd_write_cmdlines(struct tracecmd_output *handle)
 		return -1;
 	}
 
+	if (handle->compress)
+		flags |= TRACECMD_SEC_FL_COMPRESS;
+	offset = out_write_section_header(handle, TRACECMD_OPTION_CMDLINES,
+					  "command lines", flags, true);
+	if (offset == (off_t)-1)
+		return -1;
+
 	if (handle->compress)
 		out_compression_start(handle);
 
@@ -1656,6 +1722,9 @@ int tracecmd_write_cmdlines(struct tracecmd_output *handle)
 	if (handle->compress && out_compression_end(handle))
 		return -1;
 
+	if (out_update_section_header(handle, offset))
+		return -1;
+
 	handle->file_state = TRACECMD_FILE_CMD_LINES;
 	return 0;
 }
-- 
2.31.1