X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Finclude%2Fvfs.h;h=8618a048993e5471ad8f59e050000035d68cf26c;hb=9d85201216cb35e1b1e051b1d7cdc38eaa5befa4;hp=75c301289f91f9b2f22c84dbf775147613d091f4;hpb=1e7db40300bc594cf708bb6082a6e05a268da946;p=tpg%2Facess2.git diff --git a/Kernel/include/vfs.h b/Kernel/include/vfs.h index 75c30128..8618a048 100644 --- a/Kernel/include/vfs.h +++ b/Kernel/include/vfs.h @@ -5,48 +5,145 @@ /** * \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 +#include /** - * \name VFS Node Flags + * \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 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 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 + /** + * \} + */ + /** + * \name Common Functions + * \brief Functions that are used no matter the value of .Flags + * \{ + */ /** * \brief Reference the node * \param Node Pointer to this node @@ -55,6 +152,9 @@ typedef struct sVFS_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); @@ -67,6 +167,17 @@ typedef struct sVFS_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 @@ -86,6 +197,14 @@ typedef struct sVFS_Node { */ Uint64 (*Write)(struct sVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer); + /** + * \} + */ + + /** + * \name Directory Functions + * \{ + */ /** * \brief Find an directory entry by name * \param Node Pointer to this node @@ -94,7 +213,7 @@ typedef struct sVFS_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 @@ -113,18 +232,31 @@ typedef struct sVFS_Node { * \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; /** @@ -133,12 +265,12 @@ typedef struct sVFS_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) @@ -155,7 +287,8 @@ typedef struct sVFS_Driver 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 @@ -178,7 +311,7 @@ extern int VFS_AddDriver(tVFS_Driver *Info); * \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); /** * \fn tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group) * \brief Transforms Unix Permssions into Acess ACLs @@ -190,14 +323,21 @@ extern tVFS_Driver *VFS_GetFSByName(char *Name); extern tVFS_ACL *VFS_UnixToAcessACL(Uint Mode, Uint Owner, Uint Group); // --- 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 @@ -215,7 +355,7 @@ extern tVFS_Node *Inode_GetCache(int Handle, Uint64 Inode); */ 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 @@ -228,6 +368,8 @@ extern void Inode_UncacheNode(int Handle, Uint64 Inode); */ extern void Inode_ClearCache(int Handle); -//! \} +/** + * \} + */ #endif