info: Add utc_offset info for external usage

cmds/dump.c

@@ -540,7 +540,7 @@ static void dump_raw_header(struct uftrace_dump_ops *ops, struct uftrace_data *h
 	const char *info_str[] = { "EXE_NAME",	   "EXE_BUILD_ID", "EXIT_STATUS", "CMDLINE",
 				   "CPUINFO",	   "MEMINFO",	   "OSINFO",	  "TASKINFO",
 				   "USAGEINFO",	   "LOADINFO",	   "ARG_SPEC",	  "RECORD_DATE",
-				   "PATTERN_TYPE", "VERSION" };
+				   "PATTERN_TYPE", "VERSION",	   "UTC_OFFSET" };
 
 	pr_out("uftrace file header: magic         = ");
 	for (i = 0; i < UFTRACE_MAGIC_LEN; i++)

cmds/info.c

@@ -851,6 +851,41 @@ static int read_uftrace_version(void *arg)
 	return 0;
 }
 
+static int fill_utc_offset(void *arg)
+{
+	struct fill_handler_arg *fha = arg;
+	time_t current_time;
+	struct timespec ts;
+	long offset;
+
+	time(&current_time);
+	clock_gettime(clock_source, &ts);
+
+	/* calculate time offset between UTC and clock_source. */
+	offset = (long)difftime(current_time, ts.tv_sec);
+
+	dprintf(fha->fd, "utc_offset:%ld\n", offset);
+	return 0;
+}
+
+static int read_utc_offset(void *arg)
+{
+	struct read_handler_arg *rha = arg;
+	struct uftrace_data *handle = rha->handle;
+	struct uftrace_info *info = &handle->info;
+	char *buf = rha->buf;
+
+	if (fgets(buf, sizeof(rha->buf), handle->fp) == NULL)
+		return -1;
+
+	if (strncmp(buf, "utc_offset:", 11))
+		return -1;
+
+	info->utc_offset = copy_info_str(&buf[11]);
+
+	return 0;
+}
+
 struct uftrace_info_handler {
 	enum uftrace_info_bits bit;
 	int (*handler)(void *arg);
@@ -883,6 +918,7 @@ void fill_uftrace_info(uint64_t *info_mask, int fd, struct uftrace_opts *opts, i
 		{ RECORD_DATE, fill_record_date },
 		{ PATTERN_TYPE, fill_pattern_type },
 		{ VERSION, fill_uftrace_version },
+		{ UTC_OFFSET, fill_utc_offset },
 	};
 
 	for (i = 0; i < ARRAY_SIZE(fill_handlers); i++) {
@@ -926,6 +962,7 @@ int read_uftrace_info(uint64_t info_mask, struct uftrace_data *handle)
 		{ RECORD_DATE, read_record_date },
 		{ PATTERN_TYPE, read_pattern_type },
 		{ VERSION, read_uftrace_version },
+		{ UTC_OFFSET, read_utc_offset },
 	};
 
 	memset(&handle->info, 0, sizeof(handle->info));
@@ -955,6 +992,7 @@ void clear_uftrace_info(struct uftrace_info *info)
 	free(info->argspec);
 	free(info->record_date);
 	free(info->elapsed_time);
+	free(info->utc_offset);
 	free(info->uftrace_version);
 	free(info->retspec);
 	free(info->autoarg);

uftrace.h

@@ -98,6 +98,7 @@ enum uftrace_info_bits {
 	RECORD_DATE_BIT,
 	PATTERN_TYPE_BIT,
 	VERSION_BIT,
+	UTC_OFFSET_BIT,
 
 	INFO_BIT_MAX,
 
@@ -116,6 +117,7 @@ enum uftrace_info_bits {
 	RECORD_DATE = (1U << RECORD_DATE_BIT),
 	PATTERN_TYPE = (1U << PATTERN_TYPE_BIT),
 	VERSION = (1U << VERSION_BIT),
+	UTC_OFFSET = (1U << UTC_OFFSET_BIT),
 };
 
 struct uftrace_info {
@@ -142,6 +144,7 @@ struct uftrace_info {
 	double utime;
 	char *record_date;
 	char *elapsed_time;
+	char *utc_offset;
 	long vctxsw;
 	long ictxsw;
 	long maxrss;