From 4d69fcb9850b191db87d8dc8729a19c0273b95fb Mon Sep 17 00:00:00 2001
From: Elliot Thomas <elliot@midnightspark.net>
Date: Mon, 6 Mar 2023 01:21:05 +0000
Subject: Emulate 'futimesat' when __NR_futimesat is not available.

---
 libc/sysdeps/linux/common/futimesat.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/libc/sysdeps/linux/common/futimesat.c b/libc/sysdeps/linux/common/futimesat.c
index bd73eae7e..fd19fea7c 100644
--- a/libc/sysdeps/linux/common/futimesat.c
+++ b/libc/sysdeps/linux/common/futimesat.c
@@ -11,6 +11,28 @@
 
 #ifdef __NR_futimesat
 _syscall3(int, futimesat, int, fd, const char *, file, const struct timeval *, tvp)
-#else
-/* should add emulation with futimes() and /proc/self/fd/ ... */
+#elif defined __NR_utimensat
+#include <errno.h>
+#define __need_NULL
+#include <stddef.h>
+
+int futimesat(int dirfd, const char *file, const struct timeval tvp[2])
+{
+	struct timespec ts[2];
+
+	if (tvp != NULL)
+	{
+		if (tvp[0].tv_usec < 0 || tvp[0].tv_usec >= 1000000
+		    || tvp[1].tv_usec < 0 || tvp[1].tv_usec >= 1000000)
+		{
+			__set_errno(EINVAL);
+			return -1;
+		}
+
+		TIMEVAL_TO_TIMESPEC(&tvp[0], &ts[0]);
+		TIMEVAL_TO_TIMESPEC(&tvp[1], &ts[1]);
+	}
+
+	return utimensat(dirfd, file, tvp ? ts : NULL, 0);
+}
 #endif
-- 
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