dmesg: move get_boot_time() to lib/timeutils

In future the last(1) will use get_boot_time() as well.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>

1 files changed, 29 insertions, 0 deletions

diff --git a/lib/timeutils.c b/lib/timeutils.c
index 7fe62187d..c1b632e0a 100644
--- a/lib/timeutils.c
+++ b/lib/timeutils.c
@@ -21,9 +21,12 @@
 #include <assert.h>
 #include <ctype.h>
 #include <string.h>
+#include <sys/sysinfo.h>
+#include <sys/time.h>
 #include <time.h>
 
 #include "c.h"
+#include "nls.h"
 #include "strutils.h"
 #include "timeutils.h"
 
@@ -336,3 +339,29 @@ int parse_timestamp(const char *t, usec_t *usec)
 
 	return 0;
 }
+
+int get_boot_time(struct timeval *boot_time)
+{
+	struct timespec hires_uptime;
+	struct timeval lores_uptime, now;
+	struct sysinfo info;
+
+	if (gettimeofday(&now, NULL) != 0) {
+		warn(_("gettimeofday failed"));
+		return -errno;
+	}
+#ifdef CLOCK_BOOTTIME
+	if (clock_gettime(CLOCK_BOOTTIME, &hires_uptime) == 0) {
+		TIMESPEC_TO_TIMEVAL(&lores_uptime, &hires_uptime);
+		timersub(&now, &lores_uptime, boot_time);
+		return 0;
+	}
+#endif
+	/* fallback */
+	if (sysinfo(&info) != 0)
+		warn(_("sysinfo failed"));
+
+	boot_time->tv_sec = now.tv_sec - info.uptime;
+	boot_time->tv_usec = 0;
+	return 0;
+}