[PATCH v2 03/13] commands: uptime: enable structured I/O

[Ahmad Fatoum]

The uptime command can format the uptime into a human readable time
string. We have no API to capture this output, so let's add one by using
structured I/O.

Signed-off-by: Ahmad Fatoum <a.fat...@barebox.org>
---
v1 -> v2:
  - no change
---
 commands/uptime.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/commands/uptime.c b/commands/uptime.c
index d67538631c8f..7d7d8fa9be70 100644
--- a/commands/uptime.c
+++ b/commands/uptime.c
@@ -4,26 +4,31 @@
 #include <command.h>
 #include <clock.h>
 #include <getopt.h>
+#include <structio.h>
 #include <linux/math64.h>
 
+#define BUFSIZE                128
+
 #define NSEC_PER_MINUTE        (NSEC_PER_SEC * 60LL)
 #define NSEC_PER_HOUR  (NSEC_PER_MINUTE * 60LL)
 #define NSEC_PER_DAY   (NSEC_PER_HOUR * 24LL)
 #define NSEC_PER_WEEK  (NSEC_PER_DAY * 7LL)
 
-static bool print_with_unit(u64 val, const char *unit, bool comma)
+static bool print_with_unit(char *buf, u64 val, const char *unit, bool comma)
 {
        if (!val)
                return comma;
 
-       printf("%s%llu %s%s", comma ? ", " : "", val, unit, val > 1 ? "s" : "");
+       snprintf(buf, BUFSIZE,
+                "%s%llu %s%s", comma ? ", " : "", val, unit, val > 1 ? "s" : 
"");
        return true;
 }
 
 static int do_uptime(int argc, char *argv[])
 {
+       char buf[BUFSIZE];
        u64 timestamp, weeks, days, hours, minutes;
-       bool comma = false;
+       bool nanoseconds = false, comma = false;
        int opt;
 
        timestamp = get_time_ns();
@@ -31,8 +36,8 @@ static int do_uptime(int argc, char *argv[])
        while((opt = getopt(argc, argv, "n")) > 0) {
                switch(opt) {
                case 'n':
-                       printf("up %lluns\n", timestamp);
-                       return 0;
+                       nanoseconds = true;
+                       break;
                default:
                        return COMMAND_ERROR_USAGE;
                }
@@ -41,24 +46,29 @@ static int do_uptime(int argc, char *argv[])
        if (optind != argc)
                return COMMAND_ERROR_USAGE;
 
-       printf("up ");
+       stnoprintf("up ");
+
+       if (nanoseconds) {
+               stprintf_single("uptime", "%lluns", timestamp);
+               return 0;
+       }
 
        weeks = div64_u64_rem(timestamp, NSEC_PER_WEEK, &timestamp);
        days = div64_u64_rem(timestamp, NSEC_PER_DAY, &timestamp);
        hours = div64_u64_rem(timestamp, NSEC_PER_HOUR, &timestamp);
        minutes = div64_u64_rem(timestamp, NSEC_PER_MINUTE, &timestamp);
 
-       comma = print_with_unit(weeks, "week", false);
-       comma = print_with_unit(days, "day", comma);
-       comma = print_with_unit(hours, "hour", comma);
-       comma = print_with_unit(minutes, "minute", comma);
+       comma = print_with_unit(buf, weeks, "week", false);
+       comma = print_with_unit(buf, days, "day", comma);
+       comma = print_with_unit(buf, hours, "hour", comma);
+       comma = print_with_unit(buf, minutes, "minute", comma);
 
        if (!comma) {
                u64 seconds = div64_u64_rem(timestamp, NSEC_PER_SEC, 
&timestamp);
-               print_with_unit(seconds, "second", false);
+               print_with_unit(buf, seconds, "second", false);
        }
 
-       printf("\n");
+       stprintf_single("uptime", "%s", buf);
 
        return 0;
 }
-- 
2.39.5