basic _syscall_fs_wait() impl, doesn't pass the req yet

6 files changed, 53 insertions, 4 deletions

diff --git a/src/init/main.c b/src/init/main.c
index 41f51d3..8d677af 100644
--- a/src/init/main.c
+++ b/src/init/main.c
@@ -30,8 +30,18 @@ int main(void) {
 void fs_test(void) {
 	handle_t front, back, file;
 	front = _syscall_fs_create((void*)&back); // TODO change user_ptr to void*
-	_syscall_mount(front, argify("/mnt"));
-	file = _syscall_open(argify("/mnt/test"));
+
+	if (_syscall_fork()) {
+		// child: is the fs server
+		log("fs_wait started. ");
+		_syscall_fs_wait(back, NULL);
+		log("fs_wait returned. ");
+	} else {
+		// parent: accesses the fs
+		_syscall_mount(front, argify("/mnt"));
+		log("requesting file. ");
+		file = _syscall_open(argify("/mnt/test"));
+	}
 }
 
 void misc_tests(void) {
diff --git a/src/init/syscalls.c b/src/init/syscalls.c
index 4c645c2..c091247 100644
--- a/src/init/syscalls.c
+++ b/src/init/syscalls.c
@@ -40,3 +40,7 @@ int _syscall_close(handle_t handle) {
 handle_t _syscall_fs_create(user_ptr back) {
 	return _syscall(_SYSCALL_FS_CREATE, (int)back, 0, 0);
 }
+
+int _syscall_fs_wait(handle_t back, user_ptr info) {
+	return _syscall(_SYSCALL_FS_WAIT, back, info, 0);
+}
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 0b557fb..fcd3c1e 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -200,6 +200,27 @@ fail:
 	return -1;
 }
 
+int _syscall_fs_wait(handle_t back, user_ptr info) {
+	struct handle *back_handle;
+
+	if (back < 0 || back >= HANDLE_MAX) return -1;
+	back_handle = &process_current->handles[back];
+	if (back_handle->type != HANDLE_FS_BACK)
+		return -1;
+
+	process_current->state = PS_WAITS4REQUEST;
+	back_handle->fs.backend->handler = process_current;
+
+	if (back_handle->fs.backend->queue) {
+		// handle queued requests
+		struct process *queued = back_handle->fs.backend->queue;
+		back_handle->fs.backend->queue = NULL; // TODO get the next queued proc
+		vfs_request_pass2handler(queued->pending_req);
+	} else {
+		process_switch_any();
+	}
+}
+
 int syscall_handler(int num, int a, int b, int c) {
 	switch (num) {
 		case _SYSCALL_EXIT:
@@ -220,6 +241,8 @@ int syscall_handler(int num, int a, int b, int c) {
 			return _syscall_close(a);
 		case _SYSCALL_FS_CREATE:
 			return _syscall_fs_create(a);
+		case _SYSCALL_FS_WAIT:
+			return _syscall_fs_wait(a, b);
 		default:
 			tty_const("unknown syscall ");
 			panic();
diff --git a/src/kernel/vfs/backend.c b/src/kernel/vfs/backend.c
index 7e53e51..4b22104 100644
--- a/src/kernel/vfs/backend.c
+++ b/src/kernel/vfs/backend.c
@@ -27,14 +27,22 @@ _Noreturn void vfs_backend_dispatch(struct vfs_backend *backend, struct vfs_op o
 				process_current->pending_req = req;
 				process_switch_any();
 			} else {
-				assert(backend->handler->state == PS_WAITS4REQUEST);
-				panic(); // TODO
+				vfs_request_pass2handler(req);
 			}
 		default:
 			panic();
 	}
 }
 
+_Noreturn void vfs_request_pass2handler(struct vfs_op_request *req) {
+	assert(req->backend->handler);
+	assert(req->backend->handler->state == PS_WAITS4REQUEST);
+
+	req->backend->handler->state = PS_RUNNING;
+	// TODO pass the request to the process
+	process_switch(req->backend->handler);
+}
+
 // returns from a VFS operation to the calling process
 _Noreturn void vfs_backend_finish(struct vfs_op_request *req, int ret) {
 	struct process *caller = req->caller;
diff --git a/src/kernel/vfs/backend.h b/src/kernel/vfs/backend.h
index bf16ee7..bc0dc45 100644
--- a/src/kernel/vfs/backend.h
+++ b/src/kernel/vfs/backend.h
@@ -25,4 +25,5 @@ struct vfs_op_request {
 
 // these can switch processes
 _Noreturn void vfs_backend_dispatch(struct vfs_backend *backend, struct vfs_op op);
+_Noreturn void vfs_request_pass2handler(struct vfs_op_request *);
 _Noreturn void vfs_backend_finish(struct vfs_op_request *, int ret);
diff --git a/src/shared/syscalls.h b/src/shared/syscalls.h
index 29836b0..7b130c1 100644
--- a/src/shared/syscalls.h
+++ b/src/shared/syscalls.h
@@ -21,6 +21,7 @@ enum {
 	_SYSCALL_CLOSE,
 
 	_SYSCALL_FS_CREATE,
+	_SYSCALL_FS_WAIT,
 };
 
 /** Kills the current process.
@@ -50,3 +51,5 @@ int _syscall_close(handle_t);
  * @param back a pointer to a handle_t which will store the back pointer
  */
 handle_t _syscall_fs_create(user_ptr back);
+
+int _syscall_fs_wait(handle_t back, user_ptr info);