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      1 // Copyright (c) 2012 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_MOUNT_NODE_H_
      6 #define LIBRARIES_NACL_IO_MOUNT_NODE_H_
      7 
      8 #include <string>
      9 
     10 #include "nacl_io/error.h"
     11 #include "nacl_io/event_listener.h"
     12 #include "nacl_io/osdirent.h"
     13 #include "nacl_io/osstat.h"
     14 #include "nacl_io/ostermios.h"
     15 
     16 #include "sdk_util/ref_object.h"
     17 #include "sdk_util/scoped_ref.h"
     18 #include "sdk_util/simple_lock.h"
     19 
     20 namespace nacl_io {
     21 
     22 class Mount;
     23 class MountNode;
     24 
     25 typedef sdk_util::ScopedRef<MountNode> ScopedMountNode;
     26 
     27 // NOTE: The KernelProxy is the only class that should be setting errno. All
     28 // other classes should return Error (as defined by nacl_io/error.h).
     29 class MountNode : public EventListener {
     30  protected:
     31   explicit MountNode(Mount* mount);
     32   virtual ~MountNode();
     33 
     34  protected:
     35   // Initialize with node specific flags, in this case stat permissions.
     36   virtual Error Init(int flags);
     37   virtual void Destroy();
     38 
     39  public:
     40    // Declared in EventEmitter. defaults to signalled.
     41    virtual uint32_t GetEventStatus();
     42 
     43   // Normal OS operations on a node (file), can be called by the kernel
     44   // directly so it must lock and unlock appropriately.  These functions
     45   // must not be called by the mount.
     46   virtual Error FSync();
     47   // It is expected that the derived MountNode will fill with 0 when growing
     48   // the file.
     49   virtual Error FTruncate(off_t length);
     50   // Assume that |out_bytes| is non-NULL.
     51   virtual Error GetDents(size_t offs,
     52                          struct dirent* pdir,
     53                          size_t count,
     54                          int* out_bytes);
     55   // Assume that |stat| is non-NULL.
     56   virtual Error GetStat(struct stat* stat);
     57   // Assume that |arg| is non-NULL.
     58   virtual Error Ioctl(int request, char* arg);
     59   // Assume that |buf| and |out_bytes| are non-NULL.
     60   virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
     61   // Assume that |buf| and |out_bytes| are non-NULL.
     62   virtual Error Write(size_t offs,
     63                       const void* buf,
     64                       size_t count,
     65                       int* out_bytes);
     66   // Assume that |addr| and |out_addr| are non-NULL.
     67   virtual Error MMap(void* addr,
     68                      size_t length,
     69                      int prot,
     70                      int flags,
     71                      size_t offset,
     72                      void** out_addr);
     73   virtual Error Tcflush(int queue_selector);
     74   virtual Error Tcgetattr(struct termios* termios_p);
     75   virtual Error Tcsetattr(int optional_actions,
     76                           const struct termios *termios_p);
     77 
     78   virtual int GetLinks();
     79   virtual int GetMode();
     80   virtual int GetType();
     81   // Assume that |out_size| is non-NULL.
     82   virtual Error GetSize(size_t* out_size);
     83   virtual bool IsaDir();
     84   virtual bool IsaFile();
     85   virtual bool IsaTTY();
     86 
     87 
     88   // Number of children for this node (directory)
     89   virtual int ChildCount();
     90 
     91  protected:
     92   // Directory operations on the node are done by the Mount. The mount's lock
     93   // must be held while these calls are made.
     94 
     95   // Adds or removes a directory entry updating the link numbers and refcount
     96   // Assumes that |node| is non-NULL.
     97   virtual Error AddChild(const std::string& name, const ScopedMountNode& node);
     98   virtual Error RemoveChild(const std::string& name);
     99 
    100   // Find a child and return it without updating the refcount
    101   // Assumes that |out_node| is non-NULL.
    102   virtual Error FindChild(const std::string& name, ScopedMountNode* out_node);
    103 
    104   // Update the link count
    105   virtual void Link();
    106   virtual void Unlink();
    107 
    108  protected:
    109   struct stat stat_;
    110   sdk_util::SimpleLock node_lock_;
    111 
    112   // We use a pointer directly to avoid cycles in the ref count.
    113   // TODO(noelallen) We should change this so it's unnecessary for the node
    114   // to track it's parent.  When a node is unlinked, the mount should do
    115   // any cleanup it needs.
    116   Mount* mount_;
    117 
    118   friend class Mount;
    119   friend class MountDev;
    120   friend class MountHtml5Fs;
    121   friend class MountHttp;
    122   friend class MountMem;
    123   friend class MountNodeDir;
    124 };
    125 
    126 }  // namespace nacl_io
    127 
    128 #endif  // LIBRARIES_NACL_IO_MOUNT_NODE_H_
    129