Kernel/LibC: Add basic support for pthread_{create,exit}

userspace/libraries/LibC/CMakeLists.txt

@@ -17,6 +17,7 @@ set(LIBC_SOURCES
 	netdb.cpp
 	poll.cpp
 	printf_impl.cpp
+	pthread.cpp
 	pwd.cpp
 	scanf_impl.cpp
 	setjmp.cpp

userspace/libraries/LibC/include/sys/syscall.h

@@ -90,6 +90,8 @@ __BEGIN_DECLS
 	O(SYS_FSYNC,			fsync)			\
 	O(SYS_SYMLINKAT,		symlinkat)		\
 	O(SYS_HARDLINKAT,		hardlinkat)		\
+	O(SYS_PTHREAD_CREATE,	pthread_create)	\
+	O(SYS_PTHREAD_EXIT,		pthread_exit)	\
 
 enum Syscall
 {

userspace/libraries/LibC/pthread.cpp

@@ -0,0 +1,49 @@
+#include <BAN/Assert.h>
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+struct pthread_trampoline_info_t
+{
+	void* (*start_routine)(void*);
+	void* arg;
+};
+
+static void pthread_trampoline(void* arg)
+{
+	pthread_trampoline_info_t info;
+	memcpy(&info, arg, sizeof(pthread_trampoline_info_t));
+	free(arg);
+
+	pthread_exit(info.start_routine(info.arg));
+	ASSERT_NOT_REACHED();
+}
+
+int pthread_create(pthread_t* __restrict thread, const pthread_attr_t* __restrict attr, void* (*start_routine)(void*), void* __restrict arg)
+{
+	auto* info = static_cast<pthread_trampoline_info_t*>(malloc(sizeof(pthread_trampoline_info_t)));
+	if (info == nullptr)
+		return -1;
+	info->start_routine = start_routine;
+	info->arg = arg;
+
+	const auto ret = syscall(SYS_PTHREAD_CREATE, attr, pthread_trampoline, info);
+	if (ret == -1)
+	{
+		free(info);
+		return -1;
+	}
+
+	if (thread)
+		*thread = ret;
+	return 0;
+}
+
+void pthread_exit(void* value_ptr)
+{
+	syscall(SYS_PTHREAD_EXIT, value_ptr);
+	ASSERT_NOT_REACHED();
+}

userspace/tests/test-pthread/CMakeLists.txt

@@ -0,0 +1,8 @@
+set(SOURCES
+	main.cpp
+)
+
+add_executable(test-pthread ${SOURCES})
+banan_link_library(test-pthread libc)
+
+install(TARGETS test-pthread OPTIONAL)

userspace/tests/test-pthread/main.cpp

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+
+void* thread_func(void*)
+{
+	printf("hello from thread\n");
+	return nullptr;
+}
+
+int main(int argc, char** argv)
+{
+	pthread_t tid;
+
+	printf("creating thread\n");
+
+	if (pthread_create(&tid, nullptr, &thread_func, nullptr) == -1)
+	{
+		perror("pthread_create");
+		return 1;
+	}
+
+	sleep(1);
+
+	printf("exiting\n");
+
+	return 0;
+}