linux-kernel - [PATCH 14/15] tools/nolibc: implement fall back to sys_clock

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Message-Id: <20250423-nolibc-misc-v1-14-a925bf40297b@linutronix.de>
Date: Wed, 23 Apr 2025 17:01:44 +0200
From: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
To: Willy Tarreau <w@....eu>, 
 Thomas Weißschuh <linux@...ssschuh.net>, 
 Shuah Khan <shuah@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 Thomas Weißschuh <thomas.weissschuh@...utronix.de>
Subject: [PATCH 14/15] tools/nolibc: implement fall back to
 sys_clock_gettime() in gettimeofday()

Newer architectures (like riscv32) do not implement sys_gettimeofday().
In those cases fall back to sys_clock_gettime().
While that does not support the timezone argument of sys_gettimeofday(),
specifying this argument invokes undefined behaviour, so it's safe to ignore.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@...utronix.de>
---
 tools/include/nolibc/sys/time.h | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/sys/time.h b/tools/include/nolibc/sys/time.h
index 1d326c05ee627b6bdb7d2777cbb11eea385f2407..e949844bf642a4ffd8a95d95752d4b9c37d71ac5 100644
--- a/tools/include/nolibc/sys/time.h
+++ b/tools/include/nolibc/sys/time.h
@@ -10,6 +10,8 @@
 #include "../arch.h"
 #include "../sys.h"
 
+static int sys_clock_gettime(clockid_t clockid, struct timespec *tp);
+
 /*
  * int gettimeofday(struct timeval *tv, struct timezone *tz);
  */
@@ -20,7 +22,18 @@ int sys_gettimeofday(struct timeval *tv, struct timezone *tz)
 #ifdef __NR_gettimeofday
 	return my_syscall2(__NR_gettimeofday, tv, tz);
 #else
-	return __nolibc_enosys(__func__, tv, tz);
+	(void) tz; /* Non-NULL tz is undefined behaviour */
+
+	struct timespec tp;
+	int ret;
+
+	ret = sys_clock_gettime(CLOCK_REALTIME, &tp);
+	if (!ret && tv) {
+		tv->tv_sec = tp.tv_sec;
+		tv->tv_usec = tp.tv_nsec / 1000;
+	}
+
+	return ret;
 #endif
 }
 

-- 
2.49.0