From a705fdcb15c0515d512d54df43d3738b708ead65 Mon Sep 17 00:00:00 2001
From: Frank Fesevur <fesevur@gmail.com>
Date: Wed, 26 Dec 2012 23:14:09 +1100
Subject: [PATCH] uptime: add since option

The --since or -s option will show the time since the host was online.
Reference(s):
http://www.freelists.org/post/procps/Patch-Added-since-option-to-uptime

Signed-off-by: Craig Small <csmall@enc.com.au>
---
 uptime.1 |  5 ++++-
 uptime.c | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/uptime.1 b/uptime.1
index 11fa036c..13a9125e 100644
--- a/uptime.1
+++ b/uptime.1
@@ -1,6 +1,6 @@
 .\"             -*-Nroff-*-
 .\"
-.TH UPTIME "1" "June 2011" "procps-ng" "User Commands"
+.TH UPTIME "1" "December 2012" "procps-ng" "User Commands"
 .SH NAME
 uptime \- Tell how long the system has been running.
 .SH SYNOPSIS
@@ -28,6 +28,9 @@ the time.
 \fB\-h\fR, \fB\-\-help\fR
 display this help text
 .TP
+\fB\-s\fR, \fB\-\-since\fR
+system up since, in yyyy-mm-dd MM:HH:SS format
+.TP
 \fB\-V\fR, \fB\-\-version\fR
 display version information and exit
 .SH FILES
diff --git a/uptime.c b/uptime.c
index 3ea14e76..ac4579cd 100644
--- a/uptime.c
+++ b/uptime.c
@@ -21,19 +21,45 @@
 #include <getopt.h>
 #include <stdlib.h>
 #include <stdio.h>
+#include <time.h>
+#include <sys/time.h>
 
 #include "c.h"
 #include "fileutils.h"
 #include "nls.h"
+#include "proc/sysinfo.h"
 #include "proc/whattime.h"
 #include "proc/version.h"
 
+static void print_uptime_since()
+{
+	double now, uptime_secs, idle_secs;
+	time_t up_since_secs;
+	struct tm *up_since;
+	struct timeval tim;
+
+	/* Get the current time and convert it to a double */
+	gettimeofday(&tim, NULL);
+	now = tim.tv_sec + (tim.tv_usec / 1000000.0);
+
+	/* Get the uptime and calculate when that was */
+	uptime(&uptime_secs, &idle_secs);
+	up_since_secs = (time_t) ((now - uptime_secs) + 0.5);
+
+	/* Show this */
+	up_since = localtime(&up_since_secs);
+	printf("%04d-%02d-%02d %02d:%02d:%02d\n",
+		up_since->tm_year + 1900, up_since->tm_mon + 1, up_since->tm_mday,
+		up_since->tm_hour, up_since->tm_min, up_since->tm_sec);
+}
+
 static void __attribute__ ((__noreturn__)) usage(FILE * out)
 {
 	fputs(USAGE_HEADER, out);
 	fprintf(out, _(" %s [options]\n"), program_invocation_short_name);
 	fputs(USAGE_OPTIONS, out);
 	fputs(USAGE_HELP, out);
+	fputs(_(" -s, --since    system up since\n"), out);
 	fputs(USAGE_VERSION, out);
 	fprintf(out, USAGE_MAN_TAIL("uptime(1)"));
 
@@ -46,6 +72,7 @@ int main(int argc, char **argv)
 
 	static const struct option longopts[] = {
 		{"help", no_argument, NULL, 'h'},
+		{"since", no_argument, NULL, 's'},
 		{"version", no_argument, NULL, 'V'},
 		{NULL, 0, NULL, 0}
 	};
@@ -56,10 +83,13 @@ int main(int argc, char **argv)
 	textdomain(PACKAGE);
 	atexit(close_stdout);
 
-	while ((c = getopt_long(argc, argv, "hV", longopts, NULL)) != -1)
+	while ((c = getopt_long(argc, argv, "hsV", longopts, NULL)) != -1)
 		switch (c) {
 		case 'h':
 			usage(stdout);
+		case 's':
+			print_uptime_since();
+			return EXIT_SUCCESS;
 		case 'V':
 			printf(PROCPS_NG_VERSION);
 			return EXIT_SUCCESS;