vfs: Add devtmpfs + memfiles

include/zinnia/chardev.h

@@ -0,0 +1,46 @@
+// SPDX-License-Identifier: ISC
+
+#pragma once
+
+#include <zinnia/errno.h>
+#include <zinnia/initgraph.h>
+#include <zinnia/refcount.h>
+#include <zinnia/types.h>
+#include <zinnia/vfs.h>
+#include <stdint.h>
+
+static inline dev_t dev_make(uint32_t major, uint32_t minor) {
+    return (minor & 0xFF) | ((major & 0xFFF) << 8) | ((dev_t)(minor & ~0xFFU) << 12) | ((dev_t)(major & ~0xFFFU) << 32);
+}
+
+struct chardev;
+
+struct chardev_ops {
+    errno_t (*open)(struct chardev* dev, struct vfs_file* file);
+    void (*destroy)(struct chardev* dev);
+};
+
+struct chardev {
+    struct refcount rc;
+    const struct chardev_ops* ops;
+    const struct vfs_file_ops* file_ops;
+    dev_t dev;
+};
+
+void chardev_init(
+    struct chardev* dev,
+    const struct chardev_ops* ops,
+    const struct vfs_file_ops* file_ops,
+    uint32_t major,
+    uint32_t minor
+);
+void chardev_ref(struct chardev* dev);
+void chardev_unref(struct chardev* dev);
+
+struct vfs_path devtmpfs_root();
+errno_t devtmpfs_add_chardev(const char* name, struct chardev* dev, mode_t mode);
+errno_t devtmpfs_mkdir(const char* name, mode_t mode);
+errno_t devtmpfs_remove(const char* name);
+errno_t devtmpfs_symlink(const char* name, const char* target);
+
+INIT_EXTERN(devtmpfs_stage);