hwclock: make it report system/rtc clock difference

function                                             old     new   delta
rtc_tm2time                                            -      89     +89
read_rtc                                              23      86     +63
rtc_read_tm                                            -      49     +49
hwclock_main                                         428     466     +38
rtcwake_main                                         453     477     +24
rtc_read_time                                        142       -    -142
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 3/0 up/down: 263/-142)          Total: 121 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/libbb/rtc.c b/libbb/rtc.c
index 2f38b8a7e..9807e1cf9 100644
--- a/libbb/rtc.c
+++ b/libbb/rtc.c
@@ -59,15 +59,17 @@ int FAST_FUNC rtc_xopen(const char **default_rtc, int flags)
         return xopen(*default_rtc, flags);
 }
 
-time_t FAST_FUNC rtc_read_time(int fd, int utc)
+void FAST_FUNC rtc_read_tm(struct tm *tm, int fd)
 {
-        struct tm tm;
-        char *oldtz = 0;
-        time_t t = 0;
+        memset(tm, 0, sizeof(*tm));
+        xioctl(fd, RTC_RD_TIME, tm);
+        tm->tm_isdst = -1; /* "not known" */
+}
 
-        memset(&tm, 0, sizeof(struct tm));
-        xioctl(fd, RTC_RD_TIME, &tm);
-        tm.tm_isdst = -1; /* not known */
+time_t FAST_FUNC rtc_tm2time(struct tm *tm, int utc)
+{
+        char *oldtz = oldtz; /* for compiler */
+        time_t t;
 
         if (utc) {
                 oldtz = getenv("TZ");
@@ -75,7 +77,7 @@ time_t FAST_FUNC rtc_read_time(int fd, int utc)
                 tzset();
         }
 
-        t = mktime(&tm);
+        t = mktime(tm);
 
         if (utc) {
                 unsetenv("TZ");