[PATCH 1/2] libbb/rtc: rtc_read_tm: return error code on RTC_RD_TIME failure

rtc_read_tm() used xioctl() which calls bb_simple_perror_msg_and_die()
on any ioctl failure, giving callers no way to distinguish error cases.

Change the return type from void to int and use a plain ioctl() call.
Return -errno on failure, 0 on success. This lets callers inspect the
error and decide how to handle it rather than always dying.

Signed-off-by: Thomas Perrot <[email protected]>
Reviewed-by: Alexandre Belloni <[email protected]>
---
 include/rtc_.h | 2 +-
 libbb/rtc.c    | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/include/rtc_.h b/include/rtc_.h
index 7829660908a5..4f0ce05720d5 100644
--- a/include/rtc_.h
+++ b/include/rtc_.h
@@ -19,7 +19,7 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
 int rtc_adjtime_is_utc(void) FAST_FUNC;
 int rtc_xopen(const char **default_rtc, int flags) FAST_FUNC;
-void rtc_read_tm(struct tm *ptm, int fd) FAST_FUNC;
+int rtc_read_tm(struct tm *ptm, int fd) FAST_FUNC;
 time_t rtc_tm2time(struct tm *ptm, int utc) FAST_FUNC;
 
 
diff --git a/libbb/rtc.c b/libbb/rtc.c
index 54b52f23a3c6..43ef2a7086cf 100644
--- a/libbb/rtc.c
+++ b/libbb/rtc.c
@@ -78,11 +78,13 @@ int FAST_FUNC rtc_xopen(const char **default_rtc, int flags)
 	}
 }
 
-void FAST_FUNC rtc_read_tm(struct tm *ptm, int fd)
+int FAST_FUNC rtc_read_tm(struct tm *ptm, int fd)
 {
 	memset(ptm, 0, sizeof(*ptm));
-	xioctl(fd, RTC_RD_TIME, ptm);
+	if (ioctl(fd, RTC_RD_TIME, ptm) < 0)
+		return -errno;
 	ptm->tm_isdst = -1; /* "not known" */
+	return 0;
 }
 
 time_t FAST_FUNC rtc_tm2time(struct tm *ptm, int utc)

-- 
2.54.0