root vfs: implement writing to /tty

4 files changed, 42 insertions, 6 deletions

diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 8f520ab..4718b4b 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -141,8 +141,18 @@ int _syscall_fd_read(handle_t handle, user_ptr buf, int len) {
 	return -1;
 }
 
-int _syscall_fd_write(handle_t handle, user_ptr buf, int len) {
-	if (handle < 0 || handle >= HANDLE_MAX) return -1;
+int _syscall_fd_write(handle_t handle_num, user_ptr buf, int len) {
+	struct handle *handle = &process_current->handles[handle_num];
+	if (handle_num < 0 || handle_num >= HANDLE_MAX) return -1;
+	if (handle->type != HANDLE_FILE) return -1;
+	vfs_backend_dispatch(handle->file.backend, (struct vfs_op) {
+			.type = VFSOP_WRITE,
+			.rw = {
+				.buf = buf,
+				.buf_len = len,
+				.id = handle->file.id,
+			}
+		});
 	return -1;
 }
 
diff --git a/src/kernel/vfs/backend.c b/src/kernel/vfs/backend.c
index cf73ef0..9a2b777 100644
--- a/src/kernel/vfs/backend.c
+++ b/src/kernel/vfs/backend.c
@@ -8,6 +8,7 @@ _Noreturn void vfs_backend_dispatch(struct vfs_backend *backend, struct vfs_op o
 	struct vfs_op_request req = {
 		.op = op,
 		.caller = process_current,
+		.backend = backend,
 	};
 	switch (backend->type) {
 		case VFS_BACK_ROOT:
diff --git a/src/kernel/vfs/root.c b/src/kernel/vfs/root.c
index c90557b..0f11a5b 100644
--- a/src/kernel/vfs/root.c
+++ b/src/kernel/vfs/root.c
@@ -1,6 +1,9 @@
-#include <kernel/vfs/root.h>
-#include <kernel/util.h>
+#include <kernel/mem.h>
 #include <kernel/panic.h>
+#include <kernel/proc.h>
+#include <kernel/types.h>
+#include <kernel/util.h>
+#include <kernel/vfs/root.h>
 
 int vfs_root_handler(struct vfs_op_request *req) {
 	switch (req->op.type) {
@@ -10,7 +13,20 @@ int vfs_root_handler(struct vfs_op_request *req) {
 				return 0;
 			}
 			return -1;
-		default:
-			panic();
+		case VFSOP_WRITE:
+			switch (req->op.rw.id) {
+				// every id corresponds to a special file type
+				// this is a shit way to do this but :shrug:
+				case 0: { // tty
+					struct virt_iter iter;
+					virt_iter_new(&iter, req->op.rw.buf, req->op.rw.buf_len,
+							req->caller->pages, true, false);
+					while (virt_iter_next(&iter))
+						tty_write(iter.frag, iter.frag_len);
+					return iter.prior;
+				}
+				default: panic();
+			}
+		default: panic();
 	}
 }
diff --git a/src/shared/vfs.h b/src/shared/vfs.h
index 1d4812d..d88c424 100644
--- a/src/shared/vfs.h
+++ b/src/shared/vfs.h
@@ -5,8 +5,12 @@
 
 enum vfs_op_types {
 	VFSOP_OPEN,
+	VFSOP_WRITE,
 };
 
+/* currently, this struct is fully created in kernelspace
+ * i might add a syscall which allows a process to just pass it raw, with some
+ * validation - so keep that in mind */
 struct vfs_op {
 	enum vfs_op_types type;
 	union {
@@ -14,5 +18,10 @@ struct vfs_op {
 			const char *path;
 			int path_len;
 		} open;
+		struct {
+			user_ptr buf;
+			int buf_len;
+			int id; // filled in by the kernel
+		} rw;
 	};
 };