/**
* \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 <common.h>
+#include <acess.h>
-//! \name ACL Permissions
-//! \{
/**
- * \brief Readable
- */
-#define VFS_PERM_READ 0x00000001
-/**
- * \brief Writeable
- */
-#define VFS_PERM_WRITE 0x00000002
-/**
- * \brief Append allowed
+ * \name tVFS_Node Flags
+ * \brief Flag values for tVFS_Node.Flags
+ * \{
*/
-#define VFS_PERM_APPEND 0x00000004
+//! \todo Is this still needed
+#define VFS_FFLAG_READONLY 0x01 //!< Readonly File
/**
- * \brief Executable
+ * \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_PERM_EXECUTE 0x00000008
+#define VFS_FFLAG_DIRECTORY 0x02
/**
- * \brief All permissions granted
+ * \brief Symbolic Link Flag
+ *
+ * Marks a file as a symbolic link
*/
-#define VFS_PERM_ALL 0x7FFFFFFF // Mask for permissions
+#define VFS_FFLAG_SYMLINK 0x04
/**
- * \brief Denies instead of granting permissions
- * \note Denials take precedence
+ * \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_PERM_DENY 0x80000000 // Inverts permissions
-//! \}
-
+#define VFS_FFLAG_SETUID 0x08
/**
- * \name VFS Node Flags
- * \{
+ * \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_READONLY 0x01 //!< Read-only file
-#define VFS_FFLAG_DIRECTORY 0x02 //!< Directory
-#define VFS_FFLAG_SYMLINK 0x04 //!< Symbolic Link
+#define VFS_FFLAG_SETGID 0x10
/**
* \}
*/
/**
- * \brief VFS Node
+ * \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;
+ /**
+ * \}
+ */
+
+ /**
+ * \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 controll
+ * \{
+ */
+ 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
+ /**
+ * \}
+ */
- //! Reference the node
+ /**
+ * \name Common Functions
+ * \brief Functions that are used no matter the value of .Flags
+ * \{
+ */
+ /**
+ * \brief Reference the node
+ * \param Node Pointer to this node
+ */
void (*Reference)(struct sVFS_Node *Node);
- //! Close (dereference) the node
+ /**
+ * \brief Close (dereference) the node
+ * \param Node Pointer to this node
+ *
+ * Usually .Close is used to write any changes to the node back to
+ * the persistent storage.
+ */
void (*Close)(struct sVFS_Node *Node);
- //! Send an IO Control
+
+ /**
+ * \brief Send an IO Control
+ * \param Node Pointer to this node
+ * \param Id IOCtl call number
+ * \param Data Pointer to data to pass to the driver
+ * \return Implementation defined
+ */
int (*IOCtl)(struct sVFS_Node *Node, int Id, void *Data);
- //! \brief Read from the file
+ /**
+ * \}
+ */
+
+ /**
+ * \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
+ * \param Offset Byte offset in the file
+ * \param Length Number of bytes to read
+ * \param Buffer Destination for read data
+ * \return Number of bytes read
+ */
Uint64 (*Read)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
- //! \brief Write to the file
+ /**
+ * \brief Write to the file
+ * \param Node Pointer to this node
+ * \param Offset Byte offser in the file
+ * \param Length Number of bytes to write
+ * \param Buffer Source of written data
+ * \return Number of bytes read
+ */
Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
- //! \brief Find an directory entry by name
- //! \note The node returned must be accessable until ::tVFS_Node.Close is called
+ /**
+ * \}
+ */
+
+ /**
+ * \name Directory Functions
+ * \{
+ */
+ /**
+ * \brief Find an directory entry by name
+ * \param Node Pointer to this node
+ * \param Name Name of the file wanted
+ * \return Pointer to the requested node or NULL if it cannot be found
+ * \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);
- //! \brief Read from a directory
- //! \note MUST return a heap address
+ /**
+ * \brief Read from a directory
+ * \param Node Pointer to this node
+ * \param Pos Offset in the directory
+ * \return Pointer to the name of the item on the heap (will be freed
+ * by the caller). If the directory end has been reached, NULL
+ * will be returned.
+ * If an item is required to be skipped either &::NULLNode,
+ * ::VFS_SKIP or ::VFS_SKIPN(0...1023) will be returned.
+ */
char *(*ReadDir)(struct sVFS_Node *Node, int Pos);
- //! \brief Create a node in a directory
+ /**
+ * \brief Create a node in 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 Zero on Success, non-zero on error (see errno.h)
+ */
int (*MkNod)(struct sVFS_Node *Node, char *Name, Uint Flags);
- //! \brief Relink (Rename/Remove) a file/directory
+ /**
+ * \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 Zero on Success, non-zero on error (see errno.h)
+ */
int (*Relink)(struct sVFS_Node *Node, char *OldName, char *NewName);
- //!< \todo Complete
+ /**
+ * \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 (*Link)(struct sVFS_Node *Node, struct sVFS_Node *Child, char *NewName);
+
+ /**
+ * \}
+ */
} tVFS_Node;
/**
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
extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group);
// --- Node Cache --
-//! \name Node Cache
-//! \{
+/**
+ * \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()
* \brief Gets a unique handle to 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
git.ucc.asn.au / tpg / acess2.git / blobdiff
UCC git Repository :: git.ucc.asn.au