Function wasmfs_unmount

system/lib/wasmfs/syscalls.cpp:878–907

wasmfs_unmount is similar to __syscall_unlinkat, but assumes AT_REMOVEDIR is true and will only unlink mountpoints (Empty and nonempty).

// wasmfs_unmount is similar to __syscall_unlinkat, but assumes AT_REMOVEDIR is
// true and will only unlink mountpoints (Empty and nonempty).
int wasmfs_unmount(const char* path) {
  auto parsed = path::parseParent(path, AT_FDCWD);
  if (auto err = parsed.getError()) {
    return err;
  }
  auto& [parent, childNameView] = parsed.getParentChild();
  std::string childName(childNameView);
  auto lockedParent = parent->locked();
  auto file = lockedParent.getChild(childName);
  if (!file) {
    return -ENOENT;
  }
  // Disallow removing the root directory, even if it is empty.
  if (file == wasmFS.getRootDirectory()) {
    return -EBUSY;
  }

  if (!file->dynCast<Directory>()) {
    // A normal file or symlink.
    return -ENOTDIR;
  }

  if (parent->getBackend() == file->getBackend()) {
    // The child is not a valid mountpoint.
    return -EINVAL;
  }

  // Input is valid, perform the unlink.
  return lockedParent.removeChild(childName);
}

int __syscall_getdents64(int fd, void* dirp, size_t count) {
  dirent* result = (dirent*)dirp;