D48259.1774705797.diff
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	diff --git a/lib/libc/string/swab.c b/lib/libc/string/swab.c
	--- a/lib/libc/string/swab.c
	+++ b/lib/libc/string/swab.c
	@@ -4,19 +4,22 @@
	*/

	#include <unistd.h>
	+#include <sys/endian.h>

	void
	swab(const void * __restrict from, void * __restrict to, ssize_t len)
	{
	- const unsigned char *f = from;
	- unsigned char *t = to;
	+ const uint16_t *f __aligned(1) = from;
	+ uint16_t *t __aligned(1) = to;

	+ /*
	+ * POSIX says overlapping copy behavior is undefined, however many
	+ * applications assume the old FreeBSD and current GNU libc behavior
	+ * that will swap the bytes correctly when from == to. Reading both bytes
	+ * and swapping them before writing them back accomplishes this.
	+ */
	while (len > 1) {
	- t[0] = f[1];
	- t[1] = f[0];
	-
	- f += 2;
	- t += 2;
	+ t++ = bswap16(f++);
	len -= 2;
	}
	}