user: implement mlibc as the libc, finally.

It's finally done..

Signed-off-by: kaguya <vpshinomiya@protonmail.com>

user/include/mlibc/options/posix/generic/net-if.cpp

@@ -0,0 +1,40 @@
+#include <errno.h>
+#include <net/if.h>
+#include <stdlib.h>
+
+#include <bits/ensure.h>
+#include <mlibc/debug.hpp>
+#include <mlibc/posix-sysdeps.hpp>
+
+void if_freenameindex(struct if_nameindex *) {
+	mlibc::infoLogger() << "mlibc: if_freenameindex is a no-op" << frg::endlog;
+}
+
+char *if_indextoname(unsigned int index, char *name) {
+	auto sysdep = MLIBC_CHECK_OR_ENOSYS(mlibc::sys_if_indextoname, NULL);
+
+	if(int e = sysdep(index, name); e) {
+		errno = e;
+		return nullptr;
+	}
+
+	return name;
+}
+
+struct if_nameindex *if_nameindex(void) {
+	mlibc::infoLogger() << "mlibc: if_nameindex() is a no-op" << frg::endlog;
+	errno = ENOSYS;
+	return nullptr;
+}
+
+unsigned int if_nametoindex(const char *name) {
+	auto sysdep = MLIBC_CHECK_OR_ENOSYS(mlibc::sys_if_nametoindex, 0);
+	unsigned int ret = 0;
+
+	if(int e = sysdep(name, &ret); e) {
+		errno = e;
+		return 0;
+	}
+
+	return ret;
+}