lib: fs: add library for implementing a filesystem service

lib/libfs/context.c

@@ -0,0 +1,86 @@
+#include "btree.h"
+#include "file.h"
+#include "interface.h"
+
+#include <fs/allocator.h>
+#include <fs/context.h>
+
+BTREE_DEFINE_SIMPLE_GET(struct fs_file, unsigned long, f_node, f_id, get_file);
+BTREE_DEFINE_SIMPLE_INSERT(struct fs_file, f_node, f_id, put_file);
+
+struct fs_context {
+	struct fs_superblock *ctx_sb;
+	struct fs_allocator *ctx_alloc;
+	struct btree ctx_filelist;
+
+	struct fs_vtable ctx_vtable;
+};
+
+struct fs_context *fs_context_create(
+	struct fs_allocator *alloc,
+	struct fs_superblock *sb)
+{
+	struct fs_context *ctx = fs_alloc(alloc, sizeof *ctx);
+	if (!ctx) {
+		return NULL;
+	}
+
+	memset(ctx, 0x0, sizeof *ctx);
+
+	ctx->ctx_sb = sb;
+	ctx->ctx_alloc = alloc;
+
+	ctx->ctx_vtable.open = fs_msg_open;
+
+	return ctx;
+}
+
+void fs_context_destroy(struct fs_context *ctx)
+{
+	fs_free(ctx->ctx_alloc, ctx);
+}
+
+struct fs_file *fs_context_open_file(struct fs_context *ctx, unsigned long id)
+{
+	struct fs_file *f = get_file(&ctx->ctx_filelist, id);
+	if (!f) {
+		f = fs_alloc(ctx->ctx_alloc, sizeof *f);
+		if (!f) {
+			return NULL;
+		}
+
+		memset(f, 0x0, sizeof *f);
+
+		f->f_id = id;
+		put_file(&ctx->ctx_filelist, f);
+	}
+
+	return f;
+}
+
+void fs_context_close_file(struct fs_context *ctx, struct fs_file *f)
+{
+}
+
+struct fs_dentry *fs_context_resolve_path(
+	struct fs_context *ctx,
+	const char *path)
+{
+	return NULL;
+}
+
+kern_status_t fs_context_dispatch_msg(
+	struct fs_context *ctx,
+	kern_handle_t channel,
+	struct msg_endpoint *sender,
+	struct msg_header *hdr)
+{
+	return fs_dispatch(
+		channel,
+		&ctx->ctx_vtable,
+		sender,
+		hdr,
+		NULL,
+		0,
+		ctx);
+}