user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/options/internal/generic/sigset.cpp

@@ -0,0 +1,92 @@
+#include <bits/sigset_t.h>
+#include <bits/ensure.h>
+#include <errno.h>
+#include <limits.h>
+#include <string.h>
+#include <stddef.h>
+
+namespace {
+
+template<class T> struct remove_reference { typedef T type; };
+template<class T> struct remove_reference<T&> { typedef T type; };
+
+// Assume that the struct has a member named 'sig'.
+template<typename T>
+struct sigset_type_helper {
+	using type = typename remove_reference<decltype(T::sig[0])>::type;
+	static_assert(offsetof(T, sig) == 0);
+};
+
+template<>
+struct sigset_type_helper<unsigned long> { using type = unsigned long; };
+
+template<>
+struct sigset_type_helper<unsigned long long> { using type = unsigned long long; };
+
+template<>
+struct sigset_type_helper<long> { using type = long; };
+
+template<>
+struct sigset_type_helper<long long> { using type = long long; };
+
+// Some ABIs define sigset_t as a simple integer (e.g unsigned long),
+// while others define it as a struct containing an array of integers.
+using sigset_underlying_type = sigset_type_helper<sigset_t>::type;
+
+size_t signo_to_field(int signo) {
+	return signo / (sizeof(sigset_underlying_type) * CHAR_BIT);
+}
+
+size_t signo_to_bit(int signo) {
+	return signo % (sizeof(sigset_underlying_type) * CHAR_BIT);
+}
+
+} // namespace
+
+int sigemptyset(sigset_t *sigset) {
+	memset(sigset, 0, sizeof(*sigset));
+	return 0;
+}
+
+int sigfillset(sigset_t *sigset) {
+	memset(sigset, ~0, sizeof(*sigset));
+	return 0;
+}
+
+int sigaddset(sigset_t *sigset, int sig) {
+	int signo = sig - 1;
+	if(signo < 0 || static_cast<unsigned int>(signo) >= (sizeof(sigset_t) * CHAR_BIT)) {
+		errno = EINVAL;
+		return -1;
+	}
+	auto ptr = reinterpret_cast<sigset_underlying_type *>(sigset);
+	auto field = signo_to_field(signo);
+	auto bit = signo_to_bit(signo);
+	ptr[field] |= (1UL << bit);
+	return 0;
+}
+
+int sigdelset(sigset_t *sigset, int sig) {
+	int signo = sig - 1;
+	if(signo < 0 || static_cast<unsigned int>(signo) >= (sizeof(sigset_t) * CHAR_BIT)) {
+		errno = EINVAL;
+		return -1;
+	}
+	auto ptr = reinterpret_cast<sigset_underlying_type *>(sigset);
+	auto field = signo_to_field(signo);
+	auto bit = signo_to_bit(signo);
+	ptr[field] &= ~(1UL << bit);
+	return 0;
+}
+
+int sigismember(const sigset_t *sigset, int sig) {
+	int signo = sig - 1;
+	if(signo < 0 || static_cast<unsigned int>(signo) >= (sizeof(sigset_t) * CHAR_BIT)) {
+		errno = EINVAL;
+		return -1;
+	}
+	auto ptr = reinterpret_cast<const sigset_underlying_type *>(sigset);
+	auto field = signo_to_field(signo);
+	auto bit = signo_to_bit(signo);
+	return (ptr[field] & (1UL << bit)) != 0;
+}