/**
* \file vfs.h
* \brief Acess VFS Layer
+ *
+ * The Acess Virtual File System (VFS) provides abstraction of multiple
+ * physical filesystems, network storage and devices (both hardware and
+ * virtual) to the user.
+ *
+ * The core of the VFS is the concept of a \ref tVFS_Node "VFS Node".
+ * A VFS Node represents a "file" in the VFS tree, this can be any sort
+ * of file (an ordinary file, a directory, a symbolic link or a device)
+ * depending on the bits set in the \ref tVFS_Node.Flags Flags field.
+ * - For more information see "VFS Node Flags"
*/
#ifndef _VFS_H
#define _VFS_H
#include <acess.h>
/**
- * \name VFS Node Flags
+ * \brief Thread list datatype for VFS_Select
+ */
+typedef struct sVFS_SelectList tVFS_SelectList;
+
+/**
+ * \name tVFS_Node Flags
+ * \brief Flag values for tVFS_Node.Flags
* \{
*/
-#define VFS_FFLAG_READONLY 0x01 //!< Read-only file
-#define VFS_FFLAG_DIRECTORY 0x02 //!< Directory
-#define VFS_FFLAG_SYMLINK 0x04 //!< Symbolic Link
+//! \todo Is this still needed
+#define VFS_FFLAG_READONLY 0x01 //!< Readonly File
+/**
+ * \brief Directory Flag
+ *
+ * This flag marks the tVFS_Node as describing a directory, and says
+ * that the tVFS_Node.FindDir, tVFS_Node.ReadDir, tVFS_Node.MkNod and
+ * tVFS_Node.Relink function pointers are valid.
+ * For a directory the tVFS_Node.Size field contains the number of files
+ * within the directory, or -1 for undetermined.
+ */
+#define VFS_FFLAG_DIRECTORY 0x02
+/**
+ * \brief Symbolic Link Flag
+ *
+ * Marks a file as a symbolic link
+ */
+#define VFS_FFLAG_SYMLINK 0x04
+/**
+ * \brief Set User ID Flag
+ *
+ * Allows an executable file to change it's executing user to the file's
+ * owner.
+ * In the case of a directory, it means that all immediate children will
+ * inherit the UID of the parent.
+ */
+#define VFS_FFLAG_SETUID 0x08
+/**
+ * \brief Set Group ID Flag
+ *
+ * Allows an executable file to change it's executing group to the file's
+ * owning group.
+ * In the case of a directory, it means that all immediate children will
+ * inherit the GID of the parent.
+ */
+#define VFS_FFLAG_SETGID 0x10
+
+/**
+ * \brief "Don't do Write-Back" Flag
+ *
+ * Stops the VFS from calling tVFS_Node.Write on dirty pages when a region
+ * is unmapped. Nice for read-only files and memory-only files (or
+ * pseudo-readonly filesystems)
+ */
+#define VFS_FFLAG_NOWRITEBACK
/**
* \}
*/
/**
- * \brief VFS Node
- * \todo Complete / Finalise
+ * \brief Represents a node (file or directory) in the VFS tree
+ *
+ * This structure provides the VFS with the functions required to read/write
+ * the file (or directory) that it represents.
*/
-typedef struct sVFS_Node {
- Uint64 Inode; //!< Inode ID
+typedef struct sVFS_Node
+{
+ /**
+ * \name Identifiers
+ * \brief Fields used by the driver to identify what data this node
+ * corresponds to.
+ * \{
+ */
+ Uint64 Inode; //!< Inode ID (Essentially another ImplInt)
Uint ImplInt; //!< Implementation Usable Integer
void *ImplPtr; //!< Implementation Usable Pointer
+ /**
+ * \}
+ */
+ /**
+ * \name Node State
+ * \brief Stores the misc information about the node
+ * \{
+ */
int ReferenceCount; //!< Number of times the node is used
Uint64 Size; //!< File Size
Uint32 Flags; //!< File Flags
+ /**
+ * \brief Pointer to cached data (FS Specific)
+ * \note The Inode_* functions will free when the node is uncached
+ * this if needed
+ */
+ void *Data;
+
+ /**
+ * \brief Node mutex
+ * \note Provided for the Filesystem driver's use
+ */
+ tMutex Lock;
+
+ /**
+ * \}
+ */
+
+ /**
+ * \name Times
+ * \{
+ */
Sint64 ATime; //!< Last Accessed Time
Sint64 MTime; //!< Last Modified Time
Sint64 CTime; //!< Creation Time
+ /**
+ * \}
+ */
- Uint UID; //!< Owning User
- Uint GID; //!< Owning Group
+ /**
+ * \name Access control
+ * \{
+ */
+ tUID UID; //!< ID of Owning User
+ tGID GID; //!< ID of Owning Group
int NumACLs; //!< Number of ACL entries
- tVFS_ACL *ACLs; //!< ACL Entries
+ tVFS_ACL *ACLs; //!< Access Controll List pointer
+ /**
+ * \}
+ */
+ /**
+ * \name VFS_Select() fields
+ * \{
+ */
+ int DataAvaliable;
+ tVFS_SelectList *ReadThreads; //!< Threads waiting to read
+ int BufferFull;
+ tVFS_SelectList *WriteThreads; //!< Threads waiting to write
+ int ErrorOccurred;
+ tVFS_SelectList *ErrorThreads; //!< Threads waiting for an error
+ /**
+ * \}
+ */
+
+ /**
+ * \name Common Functions
+ * \brief Functions that are used no matter the value of .Flags
+ * \{
+ */
/**
* \brief Reference the node
* \param Node Pointer to this node
*/
int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data);
+ /**
+ * \}
+ */
+
+ /**
+ * \name Buffer Functions
+ * \brief Functions for accessing a buffer-type file (normal file or
+ * symbolic link)
+ * \{
+ */
+
/**
* \brief Read from the file
* \param Node Pointer to this node
* \return Number of bytes read
*/
Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
+
+ /**
+ * \brief Map a region of a file into memory
+ * \param Node Pointer to this node
+ * \param Offset Start of the region (page aligned)
+ * \param Length Length of the region (page aligned)
+ * \param Dest Location to which to map
+ * \return Boolean Failure
+ * \note If NULL, the VFS implements it using .Read
+ */
+ int (*MMap)(struct sVFS_Node *Node, Uint64 Offset, int Length, void *Dest);
+ /**
+ * \}
+ */
+
+ /**
+ * \name Directory Functions
+ * \{
+ */
/**
* \brief Find an directory entry by name
* \param Node Pointer to this node
* \note The node returned must be accessable until ::tVFS_Node.Close
* is called and ReferenceCount reaches zero.
*/
- struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, char *Name);
+ struct sVFS_Node *(*FindDir)(struct sVFS_Node *Node, const char *Name);
/**
* \brief Read from a directory
* \param Node Pointer to this node
* \param Name Name of the new child
* \param Flags Flags to apply to the new child (directory or symlink)
- * \return Boolean success
+ * \return Zero on Success, non-zero on error (see errno.h)
*/
- int (*MkNod)(struct sVFS_Node *Node, char *Name, Uint Flags);
+ int (*MkNod)(struct sVFS_Node *Node, const char *Name, Uint Flags);
/**
* \brief Relink (Rename/Remove) a file/directory
* \param Node Pointer to this node
* \param OldName Name of the item to move/delete
* \param NewName New name (or NULL if unlinking is wanted)
- * \return Boolean Success
+ * \return Zero on Success, non-zero on error (see errno.h)
+ */
+ int (*Relink)(struct sVFS_Node *Node, const char *OldName, const char *NewName);
+
+ /**
+ * \brief Link a node to a name
+ * \param Node Pointer to this node (directory)
+ * \param Child Node to create a new link to
+ * \param NewName Name for the new link
+ * \return Zeron on success, non-zero on error (see errno.h)
*/
- int (*Relink)(struct sVFS_Node *Node, char *OldName, char *NewName);
+ int (*Link)(struct sVFS_Node *Node, struct sVFS_Node *Child, const char *NewName);
+
+ /**
+ * \}
+ */
} tVFS_Node;
/**
typedef struct sVFS_Driver
{
//! \brief Unique Identifier for this filesystem type
- char *Name;
+ const char *Name;
//! \brief Flags applying to this driver
Uint Flags;
//! \brief Callback to mount a device
- tVFS_Node *(*InitDevice)(char *Device, char **Options);
+ tVFS_Node *(*InitDevice)(const char *Device, const char **Options);
//! \brief Callback to unmount a device
void (*Unmount)(tVFS_Node *Node);
//! \brief Used internally (next driver in the chain)
extern tVFS_Node NULLNode; //!< NULL VFS Node (Ignored/Skipped)
/**
- * \name Simple ACLs to aid writing drivers
+ * \name Static ACLs
+ * \brief Simple ACLs to aid writing drivers
* \{
*/
extern tVFS_ACL gVFS_ACL_EveryoneRWX; //!< Everyone Read/Write/Execute
* \brief Get the information structure of a driver given its name
* \param Name Name of filesystem driver to find
*/
-extern tVFS_Driver *VFS_GetFSByName(char *Name);
+extern tVFS_Driver *VFS_GetFSByName(const char *Name);
+
+
+/**
+ * \brief Prepare a node for use
+ */
+extern void VFS_InitNode(tVFS_Node *Node);
+
+/**
+ * \brief Clean up a node, ready for deletion
+ * \note This should ALWAYS be called before a node is freed, as it
+ * cleans up VFS internal structures.
+ */
+extern void VFS_CleanupNode(tVFS_Node *Node);
+
/**
* \fn tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group)
* \brief Transforms Unix Permssions into Acess ACLs
*/
extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group);
+/**
+ * \brief Flags fro \a TypeFlag of VFS_SelectNode
+ * \{
+ */
+#define VFS_SELECT_READ 0x01
+#define VFS_SELECT_WRITE 0x02
+#define VFS_SELECT_ERROR 0x04
+/**
+ * \}
+ */
+
+/**
+ * \brief Wait for an event on a node
+ * \param Node Node to wait on
+ * \param Type Type of wait
+ * \param Timeout Time to wait (NULL for infinite wait)
+ * \param Name Name to show in debug output
+ * \return Number of nodes that actioned (0 or 1)
+ */
+extern int VFS_SelectNode(tVFS_Node *Node, int Type, tTime *Timeout, const char *Name);
+
+/**
+ * \brief Change the full flag on a node
+ */
+extern int VFS_MarkFull(tVFS_Node *Node, BOOL IsBufferFull);
+extern int VFS_MarkAvaliable(tVFS_Node *Node, BOOL IsDataAvaliable);
+extern int VFS_MarkError(tVFS_Node *Node, BOOL IsErrorState);
+
// --- Node Cache --
-//! \name Node Cache
-//! \{
/**
- * \fn int Inode_GetHandle()
+ * \name Node Cache
+ * \brief Functions to allow a node to be cached in memory by the VFS
+ *
+ * These functions store a node for the driver, to prevent it from having
+ * to re-generate the node on each call to FindDir. It also allows for
+ * fast cleanup when a filesystem is unmounted.
+ * \{
+ */
+/**
+ * \fn int Inode_GetHandle(void)
* \brief Gets a unique handle to the Node Cache
* \return A unique handle for use for the rest of the Inode_* functions
*/
-extern int Inode_GetHandle();
+extern int Inode_GetHandle(void);
/**
* \fn tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode)
* \brief Gets an inode from the node cache
*/
extern tVFS_Node *Inode_CacheNode(int Handle, tVFS_Node *Node);
/**
- * \fn void Inode_UncacheNode(int Handle, Uint64 Inode)
+ * \fn int Inode_UncacheNode(int Handle, Uint64 Inode)
* \brief Dereferences (and removes if needed) a node from the cache
* \param Handle A handle returned by Inode_GetHandle()
* \param Inode Value of the Inode field of the ::tVFS_Node you want to remove
*/
extern void Inode_ClearCache(int Handle);
-//! \}
+/**
+ * \}
+ */
#endif
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