user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/options/ansi/generic/signal.cpp

@@ -0,0 +1,44 @@
+
+#include <bits/ensure.h>
+#include <errno.h>
+#include <signal.h>
+
+#include <mlibc/debug.hpp>
+#include <mlibc/ansi-sysdeps.hpp>
+
+__sighandler signal(int sn, __sighandler handler) {
+	struct sigaction sa;
+	sa.sa_handler = handler;
+	sa.sa_flags = 0;
+	sigemptyset(&sa.sa_mask);
+	struct sigaction old;
+	MLIBC_CHECK_OR_ENOSYS(mlibc::sys_sigaction, SIG_ERR);
+	if(int e = mlibc::sys_sigaction(sn, &sa, &old)){
+		errno = e;
+		return SIG_ERR;
+	}
+	return old.sa_handler;
+}
+
+int raise(int sig) {
+	MLIBC_CHECK_OR_ENOSYS(mlibc::sys_getpid && mlibc::sys_kill, -1);
+	pid_t pid = mlibc::sys_getpid();
+
+	if (int e = mlibc::sys_kill(pid, sig)) {
+		errno = e;
+		return -1;
+	}
+
+	return 0;
+}
+
+// This is a POSIX extension, but we have it in here for sigsetjmp
+int sigprocmask(int how, const sigset_t *__restrict set, sigset_t *__restrict retrieve) {
+	MLIBC_CHECK_OR_ENOSYS(mlibc::sys_sigprocmask, -1);
+	if(int e = mlibc::sys_sigprocmask(how, set, retrieve); e) {
+		errno = e;
+		return -1;
+	}
+	return 0;
+}
+