user: implement mlibc as the libc, finally.

It's finally done..

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

user/include/mlibc/tests/posix/pthread_key.c

@@ -0,0 +1,95 @@
+#include <assert.h>
+#include <pthread.h>
+#include <errno.h>
+#include <limits.h>
+
+_Atomic int dtors_entered = 0;
+pthread_key_t key3;
+
+static void dtor1(void *arg) {
+	(void)arg;
+	dtors_entered++;
+
+	// Set the key during destruction to trigger dtor2 (as it only runs if
+	// the key value is non-NULL).
+	assert(!pthread_setspecific(key3, &key3));
+	assert(pthread_getspecific(key3) == &key3);
+}
+
+static void dtor2(void *arg) {
+	(void)arg;
+	dtors_entered++;
+}
+
+static void *worker1(void *arg) {
+	(void)arg;
+
+	pthread_key_t key1, key2;
+	assert(!pthread_key_create(&key1, NULL));
+	assert(!pthread_key_create(&key2, dtor1));
+	assert(!pthread_key_create(&key3, dtor2));
+
+	assert(!pthread_setspecific(key1, &key1));
+	assert(pthread_getspecific(key1) == &key1);
+
+	assert(!pthread_setspecific(key2, &key2));
+	assert(pthread_getspecific(key2) == &key2);
+
+	pthread_exit(0);
+	return NULL;
+}
+
+static void dtor3(void *arg) {
+	(void)arg;
+
+	// Make sure that we can create and destroy keys inside the dtor.
+	pthread_key_t dtorKey;
+	assert(!pthread_key_create(&dtorKey, NULL));
+
+	assert(!pthread_setspecific(dtorKey, &dtorKey));
+	assert(pthread_getspecific(dtorKey) == &dtorKey);
+
+	assert(!pthread_key_delete(dtorKey));
+}
+
+static void *worker2(void *arg) {
+	(void)arg;
+
+	pthread_key_t key;
+	assert(!pthread_key_create(&key, dtor3));
+
+	assert(!pthread_setspecific(key, &key));
+	assert(pthread_getspecific(key) == &key);
+
+	pthread_exit(0);
+	return NULL;
+}
+
+int main() {
+	// NOTE that the EINVAL return from pthread_setspecific is mlibc-specific,
+	// POSIX specifies that accessing an invalid key is undefined behavior.
+
+	assert(pthread_getspecific(PTHREAD_KEYS_MAX) == NULL);
+	assert(pthread_setspecific(PTHREAD_KEYS_MAX, NULL) == EINVAL);
+
+	pthread_key_t key;
+	assert(!pthread_key_create(&key, NULL));
+	assert(!pthread_setspecific(key, &key));
+	assert(pthread_getspecific(key) == &key);
+	assert(!pthread_key_delete(key));
+
+	pthread_t thread;
+	assert(!pthread_create(&thread, NULL, &worker1, NULL));
+	assert(!pthread_join(thread, NULL));
+
+	assert(pthread_getspecific(key) == NULL);
+	assert(!pthread_setspecific(key, &key));
+	assert(pthread_getspecific(key) == &key);
+
+	assert(dtors_entered == 2);
+
+	assert(!pthread_create(&thread, NULL, &worker2, NULL));
+	assert(!pthread_join(thread, NULL));
+
+	return 0;
+}