strndup.c\string\src - musl - musl - an implementation of the standard library for Linux-based systems

#include <stdlib.h>
#include <string.h>
char *strndup(const char *s, size_t n)
{
	size_t l = strnlen(s, n);
	char *d = malloc(l+1);
	if (!d) return NULL;
	memcpy(d, s, l);
	d[l] = 0;
	return d;
}