zircon/system/ulib/fs/file_connection.cc

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <fs/internal/file_connection.h>

#include <fcntl.h>
#include <fuchsia/io/llcpp/fidl.h>
#include <lib/fdio/io.h>
#include <lib/fdio/vfs.h>
#include <lib/zircon-internal/debug.h>
#include <lib/zx/handle.h>
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <zircon/assert.h>

#include <memory>
#include <type_traits>
#include <utility>

#include <fbl/string_buffer.h>
#include <fs/debug.h>
#include <fs/internal/fidl_transaction.h>
#include <fs/trace.h>
#include <fs/vfs_types.h>
#include <fs/vnode.h>

namespace fio = ::llcpp::fuchsia::io;

namespace fs {

namespace internal {

FileConnection::FileConnection(fs::Vfs* vfs, fbl::RefPtr<fs::Vnode> vnode, VnodeProtocol protocol,
                               VnodeConnectionOptions options)
    : Connection(vfs, std::move(vnode), protocol, options, FidlProtocol::Create<fio::File>(this)) {}

void FileConnection::Clone(uint32_t clone_flags, zx::channel object,
                           CloneCompleter::Sync completer) {
  Connection::NodeClone(clone_flags, std::move(object));
}

void FileConnection::Close(CloseCompleter::Sync completer) {
  auto result = Connection::NodeClose();
  if (result.is_error()) {
    return completer.Reply(result.error());
  }
  completer.Reply(ZX_OK);
}

void FileConnection::Describe(DescribeCompleter::Sync completer) {
  auto result = Connection::NodeDescribe();
  if (result.is_error()) {
    return completer.Close(result.error());
  }
  ConvertToIoV1NodeInfo(result.take_value(), [&](fio::NodeInfo* info) {
    completer.Reply(std::move(*info));
  });
}

void FileConnection::Sync(SyncCompleter::Sync completer) {
  Connection::NodeSync([completer = completer.ToAsync()](zx_status_t sync_status) mutable {
    completer.Reply(sync_status);
  });
}

void FileConnection::GetAttr(GetAttrCompleter::Sync completer) {
  auto result = Connection::NodeGetAttr();
  if (result.is_error()) {
    return completer.Reply(result.error(), fio::NodeAttributes());
  }
  completer.Reply(ZX_OK, result.value().ToIoV1NodeAttributes());
}

void FileConnection::SetAttr(uint32_t flags, ::llcpp::fuchsia::io::NodeAttributes attributes,
                             SetAttrCompleter::Sync completer) {
  auto result = Connection::NodeSetAttr(flags, attributes);
  if (result.is_error()) {
    return completer.Reply(result.error());
  }
  completer.Reply(ZX_OK);
}

void FileConnection::NodeGetFlags(NodeGetFlagsCompleter::Sync completer) {
  auto result = Connection::NodeNodeGetFlags();
  if (result.is_error()) {
    return completer.Reply(result.error(), 0);
  }
  completer.Reply(ZX_OK, result.value());
}

void FileConnection::NodeSetFlags(uint32_t flags, NodeSetFlagsCompleter::Sync completer) {
  auto result = Connection::NodeNodeSetFlags(flags);
  if (result.is_error()) {
    return completer.Reply(result.error());
  }
  completer.Reply(ZX_OK);
}

void FileConnection::Read(uint64_t count, ReadCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileRead] options: ", options());

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, fidl::VectorView<uint8_t>());
  }
  if (!options().rights.read) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, fidl::VectorView<uint8_t>());
  }
  if (count > fio::MAX_BUF) {
    return completer.Reply(ZX_ERR_INVALID_ARGS, fidl::VectorView<uint8_t>());
  }
  uint8_t data[fio::MAX_BUF];
  size_t actual = 0;
  zx_status_t status = vnode()->Read(data, count, offset_, &actual);
  if (status == ZX_OK) {
    ZX_DEBUG_ASSERT(actual <= count);
    offset_ += actual;
  }
  completer.Reply(status, fidl::VectorView(data, actual));
}

void FileConnection::ReadAt(uint64_t count, uint64_t offset, ReadAtCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileReadAt] options: ", options());

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, fidl::VectorView<uint8_t>());
  }
  if (!options().rights.read) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, fidl::VectorView<uint8_t>());
  }
  if (count > fio::MAX_BUF) {
    return completer.Reply(ZX_ERR_INVALID_ARGS, fidl::VectorView<uint8_t>());
  }
  uint8_t data[fio::MAX_BUF];
  size_t actual = 0;
  zx_status_t status = vnode()->Read(data, count, offset, &actual);
  if (status == ZX_OK) {
    ZX_DEBUG_ASSERT(actual <= count);
  }
  completer.Reply(status, fidl::VectorView(data, actual));
}

void FileConnection::Write(fidl::VectorView<uint8_t> data, WriteCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileWrite] options: ", options());

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, 0);
  }
  if (!options().rights.write) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, 0);
  }
  size_t actual = 0;
  zx_status_t status;
  if (options().flags.append) {
    size_t end;
    status = vnode()->Append(data.data(), data.count(), &end, &actual);
    if (status == ZX_OK) {
      offset_ = end;
    }
  } else {
    status = vnode()->Write(data.data(), data.count(), offset_, &actual);
    if (status == ZX_OK) {
      offset_ += actual;
    }
  }
  ZX_DEBUG_ASSERT(actual <= data.count());
  completer.Reply(status, actual);
}

void FileConnection::WriteAt(fidl::VectorView<uint8_t> data, uint64_t offset,
                             WriteAtCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileWriteAt] options: ", options());

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, 0);
  }
  if (!options().rights.write) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, 0);
  }
  size_t actual = 0;
  zx_status_t status = vnode()->Write(data.data(), data.count(), offset, &actual);
  ZX_DEBUG_ASSERT(actual <= data.count());
  completer.Reply(status, actual);
}

void FileConnection::Seek(int64_t offset, ::llcpp::fuchsia::io::SeekOrigin start,
                          SeekCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileSeek] options: ", options());

  static_assert(SEEK_SET == static_cast<int>(fio::SeekOrigin::START), "");
  static_assert(SEEK_CUR == static_cast<int>(fio::SeekOrigin::CURRENT), "");
  static_assert(SEEK_END == static_cast<int>(fio::SeekOrigin::END), "");

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, offset_);
  }
  fs::VnodeAttributes attr;
  zx_status_t r;
  if ((r = vnode()->GetAttributes(&attr)) < 0) {
    return completer.Close(r);
  }
  size_t n;
  switch (start) {
    case fio::SeekOrigin::START:
      if (offset < 0) {
        return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
      }
      n = offset;
      break;
    case fio::SeekOrigin::CURRENT:
      n = offset_ + offset;
      if (offset < 0) {
        // if negative seek
        if (n > offset_) {
          // wrapped around. attempt to seek before start
          return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
        }
      } else {
        // positive seek
        if (n < offset_) {
          // wrapped around. overflow
          return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
        }
      }
      break;
    case fio::SeekOrigin::END:
      n = attr.content_size + offset;
      if (offset < 0) {
        // if negative seek
        if (n > attr.content_size) {
          // wrapped around. attempt to seek before start
          return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
        }
      } else {
        // positive seek
        if (n < attr.content_size) {
          // wrapped around
          return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
        }
      }
      break;
    default:
      return completer.Reply(ZX_ERR_INVALID_ARGS, offset_);
  }
  offset_ = n;
  completer.Reply(ZX_OK, offset_);
}

void FileConnection::Truncate(uint64_t length, TruncateCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileTruncate] options: ", options());

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE);
  }
  if (!options().rights.write) {
    return completer.Reply(ZX_ERR_BAD_HANDLE);
  }

  zx_status_t status = vnode()->Truncate(length);
  return completer.Reply(status);
}

void FileConnection::GetFlags(GetFlagsCompleter::Sync completer) {
  uint32_t flags = options().ToIoV1Flags() & (kStatusFlags | ZX_FS_RIGHTS);
  return completer.Reply(ZX_OK, flags);
}

void FileConnection::SetFlags(uint32_t flags, SetFlagsCompleter::Sync completer) {
  auto options = VnodeConnectionOptions::FromIoV1Flags(flags);
  set_append(options.flags.append);
  return completer.Reply(ZX_OK);
}

void FileConnection::GetBuffer(uint32_t flags, GetBufferCompleter::Sync completer) {
  FS_PRETTY_TRACE_DEBUG("[FileGetBuffer] our options: ", options(),
                        ", incoming flags: ", ZxFlags(flags));

  if (options().flags.node_reference) {
    return completer.Reply(ZX_ERR_BAD_HANDLE, nullptr);
  }

  if ((flags & fio::VMO_FLAG_PRIVATE) && (flags & fio::VMO_FLAG_EXACT)) {
    return completer.Reply(ZX_ERR_INVALID_ARGS, nullptr);
  }
  if ((options().flags.append) && (flags & fio::VMO_FLAG_WRITE)) {
    return completer.Reply(ZX_ERR_ACCESS_DENIED, nullptr);
  }
  if (!options().rights.write && (flags & fio::VMO_FLAG_WRITE)) {
    return completer.Reply(ZX_ERR_ACCESS_DENIED, nullptr);
  }
  if (!options().rights.execute && (flags & fio::VMO_FLAG_EXEC)) {
    return completer.Reply(ZX_ERR_ACCESS_DENIED, nullptr);
  }
  if (!options().rights.read) {
    return completer.Reply(ZX_ERR_ACCESS_DENIED, nullptr);
  }

  ::llcpp::fuchsia::mem::Buffer buffer;
  zx_status_t status = vnode()->GetVmo(flags, &buffer.vmo, &buffer.size);
  completer.Reply(status, status == ZX_OK ? &buffer : nullptr);
}

}  // namespace internal

}  // namespace fs