Virtual filesystem and ramdiskfs

kernel/fs/vfs.c

@@ -0,0 +1,99 @@
+#include <fs/ramdiskfs.h>
+#include <fs/vfs.h>
+#include <libk/fieldsizeof.h>
+#include <libk/hash.h>
+#include <libk/lengthof.h>
+#include <libk/std.h>
+#include <libk/string.h>
+#include <mm/liballoc.h>
+#include <sync/spin_lock.h>
+#include <sys/debug.h>
+
+static struct vfs_mount_table mount_table;
+
+static struct vfs_mountpoint* vfs_find_mountpoint (const char* mountpoint) {
+  struct hash_node_link* found_link = NULL;
+  size_t mountpoint_len = strlen (mountpoint);
+  uint32_t hash = hash_fnv32 (mountpoint, strlen (mountpoint));
+
+  spin_lock (&mount_table.lock);
+  hash_find (&mount_table, mountpoint, mountpoint_len, hash,
+             lengthof (mount_table.mountpoint_buckets), mountpoint_buckets, struct vfs_mountpoint,
+             mount_table_link, key, found_link);
+  spin_unlock (&mount_table.lock);
+
+  if (found_link == NULL)
+    return NULL;
+
+  return hash_entry (found_link, struct vfs_mountpoint, mount_table_link);
+}
+
+struct vfs_mountpoint* vfs_create_mountpoint (const char* key, int fs_type) {
+  if (strlen_null (key) > fieldsizeof (struct vfs_mountpoint, key))
+    return NULL;
+
+  struct vfs_mountpoint* mountpoint = malloc (sizeof (*mountpoint));
+
+  if (mountpoint == NULL)
+    return NULL;
+
+  memset (mountpoint, 0, sizeof (*mountpoint));
+
+  memcpy (mountpoint->key, key, strlen_null (key));
+  mountpoint->fs_type = fs_type;
+  mountpoint->lock = SPIN_LOCK_INIT;
+
+  switch (mountpoint->fs_type) {
+  case VFS_RAMDISKFS: {
+    mountpoint->driver_ops.mount = &ramdiskfs_mount;
+    mountpoint->driver_ops.describe = &ramdiskfs_describe;
+    mountpoint->driver_ops.read = &ramdiskfs_read;
+  } break;
+  default: {
+    free (mountpoint);
+    return NULL;
+  } break;
+  }
+
+  bool ok = mountpoint->driver_ops.mount (mountpoint);
+
+  if (!ok) {
+    free (mountpoint);
+    return NULL;
+  }
+
+  uint32_t mp_hash = hash_fnv32 (mountpoint->key, strlen (mountpoint->key));
+
+  spin_lock (&mount_table.lock);
+
+  hash_insert (&mount_table, &mountpoint->mount_table_link, mp_hash,
+               lengthof (mount_table.mountpoint_buckets), mountpoint_buckets);
+
+  spin_unlock (&mount_table.lock);
+
+  return mountpoint;
+}
+
+int vfs_describe (const char* mountpoint, const char* path, struct fs_desc_buffer* desc) {
+  struct vfs_mountpoint* vmp = vfs_find_mountpoint (mountpoint);
+
+  if (vmp == NULL)
+    return -VFS_NOT_FOUND;
+
+  return vmp->driver_ops.describe (vmp, path, desc);
+}
+
+int vfs_read (const char* mountpoint, const char* path, uint8_t* buffer, size_t off, size_t size) {
+  struct vfs_mountpoint* vmp = vfs_find_mountpoint (mountpoint);
+
+  if (vmp == NULL)
+    return -VFS_NOT_FOUND;
+
+  return vmp->driver_ops.read (vmp, path, buffer, off, size);
+}
+
+void vfs_init (void) {
+  memset (&mount_table, 0, sizeof (mount_table));
+
+  mount_table.lock = SPIN_LOCK_INIT;
+}