native_client_sdk/src/libraries/nacl_io/filesystem.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef LIBRARIES_NACL_IO_FILESYSTEM_H_
   6 #define LIBRARIES_NACL_IO_FILESYSTEM_H_
   7
   8 #include <map>
   9 #include <string>
  10
  11 #include "nacl_io/error.h"
  12 #include "nacl_io/inode_pool.h"
  13 #include "nacl_io/node.h"
  14 #include "nacl_io/path.h"
  15
  16 #include "sdk_util/macros.h"
  17 #include "sdk_util/ref_object.h"
  18 #include "sdk_util/scoped_ref.h"
  19
  20 struct fuse_operations;
  21
  22 namespace nacl_io {
  23
  24 class Filesystem;
  25 class Node;
  26 class PepperInterface;
  27
  28 typedef sdk_util::ScopedRef<Filesystem> ScopedFilesystem;
  29 typedef std::map<std::string, std::string> StringMap_t;
  30
  31 // This structure is passed to all filesystems via the Filesystem::Init virtual
  32 // function.  With it, we can add or remove initialization values without
  33 // changing the function signature.
  34 struct FsInitArgs {
  35   FsInitArgs() : dev(0), ppapi(NULL), fuse_ops(NULL) {}
  36   explicit FsInitArgs(int dev) : dev(dev), ppapi(NULL), fuse_ops(NULL) {}
  37
  38   // Device number of the new filesystem.
  39   int dev;
  40   StringMap_t string_map;
  41   PepperInterface* ppapi;
  42   fuse_operations* fuse_ops;
  43 };
  44
  45 // NOTE: The KernelProxy is the only class that should be setting errno. All
  46 // other classes should return Error (as defined by nacl_io/error.h).
  47 class Filesystem : public sdk_util::RefObject {
  48  protected:
  49   // The protected functions are only used internally and will not
  50   // acquire or release the filesystem's lock.
  51   Filesystem();
  52   virtual ~Filesystem();
  53
  54   // Init must be called by the factory before the filesystem is used.
  55   // |ppapi| can be NULL. If so, this filesystem cannot make any pepper calls.
  56   virtual Error Init(const FsInitArgs& args);
  57   virtual void Destroy();
  58
  59  public:
  60   PepperInterface* ppapi() { return ppapi_; }
  61   int dev() { return dev_; }
  62
  63   // All paths in functions below are expected to containing a leading "/".
  64
  65   // Test whether a file or directory at a given path can be accessed.
  66   // Returns 0 on success, or an appropriate errno value on failure.
  67   virtual Error Access(const Path& path, int a_mode) = 0;
  68
  69   // Open a node at |path| with the specified open flags. The resulting
  70   // Node is created with a ref count of 1.
  71   // Assumes that |out_node| is non-NULL.
  72   virtual Error Open(const Path& path,
  73                      int open_flags,
  74                      ScopedNode* out_node) = 0;
  75
  76   // OpenResource is only used to read files from the NaCl NMF file. No
  77   // filesystem except PassthroughFs should implement it.
  78   // Assumes that |out_node| is non-NULL.
  79   virtual Error OpenResource(const Path& path, ScopedNode* out_node);
  80
  81   // Unlink, Mkdir, Rmdir will affect the both the RefCount
  82   // and the nlink number in the stat object.
  83   virtual Error Unlink(const Path& path) = 0;
  84   virtual Error Mkdir(const Path& path, int permissions) = 0;
  85   virtual Error Rmdir(const Path& path) = 0;
  86   virtual Error Remove(const Path& path) = 0;
  87   virtual Error Rename(const Path& path, const Path& newpath) = 0;
  88   virtual Error Filesystem_VIoctl(int request, va_list args);
  89
  90   // Helper function that forwards to Filesystem_VIoctl.
  91   Error Filesystem_Ioctl(int request, ...);
  92
  93   // Assumes that |node| is non-NULL.
  94   void OnNodeCreated(Node* node);
  95
  96   // Assumes that |node| is non-NULL.
  97   void OnNodeDestroyed(Node* node);
  98
  99  protected:
 100   // Device number for the filesystem.
 101   int dev_;
 102   PepperInterface* ppapi_;  // Weak reference.
 103   INodePool inode_pool_;
 104
 105  private:
 106   // May only be called by the KernelProxy when the Kernel's
 107   // lock is held, so we make it private.
 108   friend class KernelObject;
 109   friend class KernelProxy;
 110   DISALLOW_COPY_AND_ASSIGN(Filesystem);
 111 };
 112
 113 }  // namespace nacl_io
 114
 115 #endif  // LIBRARIES_NACL_IO_FILESYSTEM_H_