native_client_sdk/src/libraries/nacl_io/node.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_NODE_H_
   6 #define LIBRARIES_NACL_IO_NODE_H_
   7
   8 #include <stdarg.h>
   9 #include <string>
  10
  11 #include "nacl_io/error.h"
  12 #include "nacl_io/event_listener.h"
  13 #include "nacl_io/log.h"
  14 #include "nacl_io/osdirent.h"
  15 #include "nacl_io/osstat.h"
  16 #include "nacl_io/ostermios.h"
  17
  18 #include "sdk_util/ref_object.h"
  19 #include "sdk_util/scoped_ref.h"
  20 #include "sdk_util/simple_lock.h"
  21
  22 #define S_IRALL (S_IRUSR | S_IRGRP | S_IROTH)
  23 #define S_IWALL (S_IWUSR | S_IWGRP | S_IWOTH)
  24 #define S_IXALL (S_IXUSR | S_IXGRP | S_IXOTH)
  25
  26 namespace nacl_io {
  27
  28 class Filesystem;
  29 class Node;
  30 struct HandleAttr;
  31
  32 typedef sdk_util::ScopedRef<Node> ScopedNode;
  33
  34 // NOTE: The KernelProxy is the only class that should be setting errno. All
  35 // other classes should return Error (as defined by nacl_io/error.h).
  36 class Node : public sdk_util::RefObject {
  37  protected:
  38   explicit Node(Filesystem* filesystem);
  39   virtual ~Node();
  40
  41  protected:
  42   virtual Error Init(int open_flags);
  43   virtual void Destroy();
  44
  45  public:
  46   // Return true if the node permissions match the given open mode.
  47   virtual bool CanOpen(int open_flags);
  48
  49   // Returns the emitter for this Node if it has one, if not, assume this
  50   // object can not block.
  51   virtual EventEmitter* GetEventEmitter();
  52   virtual uint32_t GetEventStatus();
  53
  54   // Normal OS operations on a node (file), can be called by the kernel
  55   // directly so it must lock and unlock appropriately.  These functions
  56   // must not be called by the filesystem.
  57   virtual Error FSync();
  58   // It is expected that the derived Node will fill with 0 when growing
  59   // the file.
  60   virtual Error FTruncate(off_t length);
  61   // Assume that |out_bytes| is non-NULL.
  62   virtual Error GetDents(size_t offs,
  63                          struct dirent* pdir,
  64                          size_t count,
  65                          int* out_bytes);
  66   // Assume that |stat| is non-NULL.
  67   virtual Error GetStat(struct stat* stat);
  68   // Assume that |arg| is non-NULL.
  69   Error Ioctl(int request, ...);
  70   virtual Error VIoctl(int request, va_list args);
  71   // Assume that |buf| and |out_bytes| are non-NULL.
  72   virtual Error Read(const HandleAttr& attr,
  73                      void* buf,
  74                      size_t count,
  75                      int* out_bytes);
  76   // Assume that |buf| and |out_bytes| are non-NULL.
  77   virtual Error Write(const HandleAttr& attr,
  78                       const void* buf,
  79                       size_t count,
  80                       int* out_bytes);
  81   // Assume that |addr| and |out_addr| are non-NULL.
  82   virtual Error MMap(void* addr,
  83                      size_t length,
  84                      int prot,
  85                      int flags,
  86                      size_t offset,
  87                      void** out_addr);
  88   virtual Error Tcflush(int queue_selector);
  89   virtual Error Tcgetattr(struct termios* termios_p);
  90   virtual Error Tcsetattr(int optional_actions,
  91                           const struct termios* termios_p);
  92
  93   virtual int GetLinks();
  94   virtual int GetMode();
  95   virtual int GetType();
  96   virtual void SetType(int type);
  97   // Assume that |out_size| is non-NULL.
  98   virtual Error GetSize(off_t* out_size);
  99   // Returns 0 if node is a TTY
 100   virtual Error Isatty();
 101
 102   virtual bool IsaDir();
 103   virtual bool IsaFile();
 104   virtual bool IsaSock();
 105
 106   // Number of children for this node (directory)
 107   virtual int ChildCount();
 108
 109  protected:
 110   // Directory operations on the node are done by the Filesystem. The
 111   // filesystem's lock must be held while these calls are made.
 112
 113   // Adds or removes a directory entry updating the link numbers and refcount
 114   // Assumes that |node| is non-NULL.
 115   virtual Error AddChild(const std::string& name, const ScopedNode& node);
 116   virtual Error RemoveChild(const std::string& name);
 117
 118   // Find a child and return it without updating the refcount
 119   // Assumes that |out_node| is non-NULL.
 120   virtual Error FindChild(const std::string& name, ScopedNode* out_node);
 121
 122   // Update the link count
 123   virtual void Link();
 124   virtual void Unlink();
 125
 126  protected:
 127   struct stat stat_;
 128   sdk_util::SimpleLock node_lock_;
 129
 130   // We use a pointer directly to avoid cycles in the ref count.
 131   // TODO(noelallen) We should change this so it's unnecessary for the node
 132   // to track it's parent.  When a node is unlinked, the filesystem should do
 133   // any cleanup it needs.
 134   Filesystem* filesystem_;
 135
 136   friend class DevFs;
 137   friend class DirNode;
 138   friend class Filesystem;
 139   friend class FuseFs;
 140   friend class Html5Fs;
 141   friend class HttpFs;
 142   friend class MemFs;
 143 };
 144
 145 }  // namespace nacl_io
 146
 147 #endif  // LIBRARIES_NACL_IO_NODE_H_