lib: msg-fs: implement open() send/recv

lib/libmsg-fs/fs.c

@@ -1,3 +1,111 @@
-void msg_fs_tmp(void)
+#include <rosetta/msg/fs.h>
+#include <string.h>
+
+kern_status_t rosetta_msg_fs_open_send(
+	kern_handle_t port,
+	const char *path,
+	int flags,
+	int *out_err)
 {
+	size_t path_len = strlen(path);
+
+	struct rosetta_msg_fs_open msg = {0};
+	rosetta_msg_init(&msg.msg_base, ROSETTA_MSG_FS, ROSETTA_MSG_FS_OPEN);
+	uint16_t offset = sizeof msg;
+	msg.msg_request.o_path = offset;
+	msg.msg_request.o_path_len = path_len;
+	msg.msg_request.o_flags = flags;
+
+	struct iovec send_vec[] = {
+		IOVEC(&msg, sizeof msg),
+		IOVEC(path, path_len),
+	};
+
+	struct iovec reply_vec[] = {
+		IOVEC(&msg, sizeof msg),
+	};
+
+	struct msg req = {
+		.msg_data = send_vec,
+		.msg_data_count = sizeof send_vec / sizeof send_vec[0],
+	};
+
+	struct msg resp = {
+		.msg_data = reply_vec,
+		.msg_data_count = sizeof reply_vec / sizeof reply_vec[0],
+	};
+
+	kern_status_t status = msg_send(port, 0, &req, &resp);
+	if (status != KERN_OK) {
+		return status;
+	}
+
+	*out_err = msg.msg_response.o_err;
+
+	return KERN_OK;
+}
+
+kern_status_t rosetta_msg_fs_open_recv(
+	kern_handle_t channel,
+	msgid_t id,
+	struct rosetta_msg_string *out_path,
+	int *out_flags)
+{
+	struct rosetta_msg_fs_open msg;
+	struct iovec vec = IOVEC(&msg, sizeof msg);
+	size_t r = 0;
+
+	kern_status_t status = msg_read(channel, id, 0, &vec, 1, &r);
+	if (status != KERN_OK) {
+		return status;
+	}
+
+	if (r != sizeof msg) {
+		/* TODO better error code for malformed messages */
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	out_path->s_len = msg.msg_request.o_path_len;
+	if (out_path->s_max > 0) {
+		vec.io_base = (virt_addr_t)out_path->s_buf;
+		vec.io_len = out_path->s_max - 1;
+
+		if (vec.io_len > out_path->s_len) {
+			vec.io_len = out_path->s_len;
+		}
+
+		status = msg_read(
+			channel,
+			id,
+			msg.msg_request.o_path,
+			&vec,
+			1,
+			&r);
+		if (status != KERN_OK) {
+			return status;
+		}
+
+		if (r != out_path->s_len) {
+			return KERN_INVALID_ARGUMENT;
+		}
+
+		out_path->s_buf[out_path->s_len] = 0;
+	}
+
+	*out_flags = msg.msg_request.o_flags;
+
+	return KERN_OK;
+}
+
+kern_status_t rosetta_msg_fs_open_reply(
+	kern_handle_t channel,
+	msgid_t id,
+	int err)
+{
+	struct rosetta_msg_fs_open msg = {0};
+	msg.msg_response.o_err = err;
+	struct iovec vec = IOVEC(&msg, sizeof msg);
+
+	struct msg kmsg = {.msg_data = &vec, .msg_data_count = 1};
+	return msg_reply(channel, 0, id, &kmsg);
 }