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      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_
    116