user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/linux/ppoll.c

@@ -0,0 +1,96 @@
+#include <assert.h>
+#include <errno.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+#include <time.h>
+#include <unistd.h>
+
+static void sig_handler(int sig) {
+	(void)sig;
+}
+
+int main() {
+	int fds[2];
+	int ret = pipe(fds);
+	assert(ret == 0);
+
+	struct pollfd poll_fds[1];
+	poll_fds[0].fd = fds[0];
+	poll_fds[0].events = POLLIN;
+
+	struct timespec timeout;
+	timeout.tv_sec = 0;
+	timeout.tv_nsec = 1000000; // 1 ms
+
+	// Test that ppoll times out correctly.
+	ret = ppoll(poll_fds, 1, &timeout, NULL);
+	assert(ret == 0);
+
+	// Test that ppoll returns 1 if there is an event.
+	char buf[1];
+	ret = write(fds[1], "a", 1);
+	assert(ret == 1);
+
+	ret = ppoll(poll_fds, 1, &timeout, NULL);
+	assert(ret == 1);
+	assert(poll_fds[0].revents & POLLIN);
+
+	// Test that ppoll returns 0 if there are no events and timeout is 0.
+	ret = read(fds[0], buf, 1);
+	assert(ret == 1);
+
+	timeout.tv_nsec = 0;
+	ret = ppoll(poll_fds, 1, &timeout, NULL);
+	assert(ret == 0);
+
+	// Test that ppoll returns immediately if there is an event and timeout is 0.
+	ret = write(fds[1], "a", 1);
+	assert(ret == 1);
+
+	ret = ppoll(poll_fds, 1, &timeout, NULL);
+	assert(ret == 1);
+	assert(poll_fds[0].revents & POLLIN);
+
+	char recvbuf[2];
+	ret = read(fds[0], &recvbuf, 2);
+	assert(ret == 1);
+
+	// Test that ppoll is interrupted by a signal.
+	struct sigaction sa;
+	sa.sa_handler = sig_handler;
+	sigemptyset(&sa.sa_mask);
+	sa.sa_flags = 0;
+	ret = sigaction(SIGUSR1, &sa, NULL);
+	assert(ret == 0);
+
+	pid_t pid = fork();
+	assert(pid >= 0);
+
+	if (pid == 0) {
+		// Child process.
+		usleep(100000); // 100 ms
+		ret = kill(getppid(), SIGUSR1);
+		assert(ret == 0);
+		exit(0);
+	} else {
+		// Parent process.
+		timeout.tv_sec = 1;
+		timeout.tv_nsec = 0;
+		ret = ppoll(poll_fds, 1, &timeout, NULL);
+		assert(ret == -1);
+		assert(errno == EINTR);
+
+		int status;
+		ret = waitpid(pid, &status, 0);
+		assert(ret == pid);
+		assert(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+	}
+
+	close(fds[0]);
+	close(fds[1]);
+
+	return 0;
+}