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diff --git a/include/iprt/vfslowlevel.h b/include/iprt/vfslowlevel.h new file mode 100644 index 00000000..d1f80728 --- /dev/null +++ b/include/iprt/vfslowlevel.h @@ -0,0 +1,1515 @@ +/** @file + * IPRT - Virtual Filesystem. + */ + +/* + * Copyright (C) 2010-2020 Oracle Corporation + * + * This file is part of VirtualBox Open Source Edition (OSE), as + * available from http://www.virtualbox.org. This file is free software; + * you can redistribute it and/or modify it under the terms of the GNU + * General Public License (GPL) as published by the Free Software + * Foundation, in version 2 as it comes in the "COPYING" file of the + * VirtualBox OSE distribution. VirtualBox OSE is distributed in the + * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. + * + * The contents of this file may alternatively be used under the terms + * of the Common Development and Distribution License Version 1.0 + * (CDDL) only, as it comes in the "COPYING.CDDL" file of the + * VirtualBox OSE distribution, in which case the provisions of the + * CDDL are applicable instead of those of the GPL. + * + * You may elect to license modified versions of this file under the + * terms and conditions of either the GPL or the CDDL or both. + */ + +#ifndef IPRT_INCLUDED_vfslowlevel_h +#define IPRT_INCLUDED_vfslowlevel_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/vfs.h> +#include <iprt/errcore.h> +#include <iprt/list.h> +#include <iprt/param.h> + + +RT_C_DECLS_BEGIN + +/** @defgroup grp_rt_vfs_lowlevel RTVfs - Low-level Interface. + * @ingroup grp_rt_vfs + * @{ + */ + + +/** @name VFS Lock Abstraction + * @todo This should be moved somewhere else as it is of general use. + * @{ */ + +/** + * VFS lock types. + */ +typedef enum RTVFSLOCKTYPE +{ + /** Invalid lock type. */ + RTVFSLOCKTYPE_INVALID = 0, + /** Read write semaphore. */ + RTVFSLOCKTYPE_RW, + /** Fast mutex semaphore (critical section in ring-3). */ + RTVFSLOCKTYPE_FASTMUTEX, + /** Full fledged mutex semaphore. */ + RTVFSLOCKTYPE_MUTEX, + /** The end of valid lock types. */ + RTVFSLOCKTYPE_END, + /** The customary 32-bit type hack. */ + RTVFSLOCKTYPE_32BIT_HACK = 0x7fffffff +} RTVFSLOCKTYPE; + +/** VFS lock handle. */ +typedef struct RTVFSLOCKINTERNAL *RTVFSLOCK; +/** Pointer to a VFS lock handle. */ +typedef RTVFSLOCK *PRTVFSLOCK; +/** Nil VFS lock handle. */ +#define NIL_RTVFSLOCK ((RTVFSLOCK)~(uintptr_t)0) + +/** Special handle value for creating a new read/write semaphore based lock. */ +#define RTVFSLOCK_CREATE_RW ((RTVFSLOCK)~(uintptr_t)1) +/** Special handle value for creating a new fast mutex semaphore based lock. */ +#define RTVFSLOCK_CREATE_FASTMUTEX ((RTVFSLOCK)~(uintptr_t)2) +/** Special handle value for creating a new mutex semaphore based lock. */ +#define RTVFSLOCK_CREATE_MUTEX ((RTVFSLOCK)~(uintptr_t)3) + +/** + * Retains a reference to the VFS lock handle. + * + * @returns New reference count on success, UINT32_MAX on failure. + * @param hLock The VFS lock handle. + */ +RTDECL(uint32_t) RTVfsLockRetain(RTVFSLOCK hLock); + +/** + * Releases a reference to the VFS lock handle. + * + * @returns New reference count on success (0 if closed), UINT32_MAX on failure. + * @param hLock The VFS lock handle. + */ +RTDECL(uint32_t) RTVfsLockRelease(RTVFSLOCK hLock); + +/** + * Gets the lock type. + * + * @returns The lock type on success, RTVFSLOCKTYPE_INVALID if the handle is + * not valid. + * @param hLock The lock handle. + */ +RTDECL(RTVFSLOCKTYPE) RTVfsLockGetType(RTVFSLOCK hLock); + + + +RTDECL(void) RTVfsLockAcquireReadSlow(RTVFSLOCK hLock); +RTDECL(void) RTVfsLockReleaseReadSlow(RTVFSLOCK hLock); +RTDECL(void) RTVfsLockAcquireWriteSlow(RTVFSLOCK hLock); +RTDECL(void) RTVfsLockReleaseWriteSlow(RTVFSLOCK hLock); + +/** + * Acquire a read lock. + * + * @param hLock The lock handle, can be NIL. + */ +DECLINLINE(void) RTVfsLockAcquireRead(RTVFSLOCK hLock) +{ + if (hLock != NIL_RTVFSLOCK) + RTVfsLockAcquireReadSlow(hLock); +} + + +/** + * Release a read lock. + * + * @param hLock The lock handle, can be NIL. + */ +DECLINLINE(void) RTVfsLockReleaseRead(RTVFSLOCK hLock) +{ + if (hLock != NIL_RTVFSLOCK) + RTVfsLockReleaseReadSlow(hLock); +} + + +/** + * Acquire a write lock. + * + * @param hLock The lock handle, can be NIL. + */ +DECLINLINE(void) RTVfsLockAcquireWrite(RTVFSLOCK hLock) +{ + if (hLock != NIL_RTVFSLOCK) + RTVfsLockAcquireWriteSlow(hLock); +} + + +/** + * Release a write lock. + * + * @param hLock The lock handle, can be NIL. + */ +DECLINLINE(void) RTVfsLockReleaseWrite(RTVFSLOCK hLock) +{ + if (hLock != NIL_RTVFSLOCK) + RTVfsLockReleaseWriteSlow(hLock); +} + +/** @} */ + +/** + * The basis for all virtual file system objects. + */ +typedef struct RTVFSOBJOPS +{ + /** The structure version (RTVFSOBJOPS_VERSION). */ + uint32_t uVersion; + /** The object type for type introspection. */ + RTVFSOBJTYPE enmType; + /** The name of the operations. */ + const char *pszName; + + /** + * Close the object. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + */ + DECLCALLBACKMEMBER(int, pfnClose)(void *pvThis); + + /** + * Get information about the file. + * + * @returns IPRT status code. See RTVfsObjQueryInfo. + * @retval VERR_WRONG_TYPE if file system or file system stream. + * @param pvThis The implementation specific file data. + * @param pObjInfo Where to return the object info on success. + * @param enmAddAttr Which set of additional attributes to request. + * @sa RTVfsObjQueryInfo, RTFileQueryInfo, RTPathQueryInfo + */ + DECLCALLBACKMEMBER(int, pfnQueryInfo)(void *pvThis, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr); + + /** Marks the end of the structure (RTVFSOBJOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSOBJOPS; +/** Pointer to constant VFS object operations. */ +typedef RTVFSOBJOPS const *PCRTVFSOBJOPS; + +/** The RTVFSOBJOPS structure version. */ +#define RTVFSOBJOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x1f,1,0) + + +/** + * The VFS operations. + */ +typedef struct RTVFSOPS +{ + /** The basic object operation. */ + RTVFSOBJOPS Obj; + /** The structure version (RTVFSOPS_VERSION). */ + uint32_t uVersion; + /** The virtual file system feature mask. */ + uint32_t fFeatures; + + /** + * Opens the root directory. + * + * @returns IPRT status code. + * @param pvThis The implementation specific data. + * @param phVfsDir Where to return the handle to the root directory. + */ + DECLCALLBACKMEMBER(int, pfnOpenRoot)(void *pvThis, PRTVFSDIR phVfsDir); + + /** + * Query the status of the given storage range (optional). + * + * This can be used by the image compaction utilites to evict non-zero blocks + * that aren't currently being used by the file system. + * + * @returns IPRT status code. + * @param pvThis The implementation specific data. + * @param off Start offset to check. + * @param cb Number of bytes to check. + * @param pfUsed Where to store whether the given range is in use. + */ + DECLCALLBACKMEMBER(int, pfnQueryRangeState)(void *pvThis, uint64_t off, size_t cb, bool *pfUsed); + + /** @todo There will be more methods here to optimize opening and + * querying. */ + +#if 0 + /** + * Optional entry point for optimizing path traversal within the file system. + * + * @returns IPRT status code. + * @param pvThis The implementation specific data. + * @param pszPath The path to resolve. + * @param poffPath The current path offset on input, what we've + * traversed to on successful return. + * @param phVfs??? Return handle to what we've traversed. + * @param p??? Return other stuff... + */ + DECLCALLBACKMEMBER(int, pfnTraverse)(void *pvThis, const char *pszPath, size_t *poffPath, PRTVFS??? phVfs?, ???* p???); +#endif + + /** @todo need rename API */ + + /** Marks the end of the structure (RTVFSOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSOPS; +/** Pointer to constant VFS operations. */ +typedef RTVFSOPS const *PCRTVFSOPS; + +/** The RTVFSOPS structure version. */ +#define RTVFSOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x0f,1,0) + +/** @name RTVFSOPS::fFeatures + * @{ */ +/** The VFS supports attaching other systems. */ +#define RTVFSOPS_FEAT_ATTACH RT_BIT_32(0) +/** @} */ + +/** + * Creates a new VFS handle. + * + * @returns IPRT status code + * @param pVfsOps The VFS operations. + * @param cbInstance The size of the instance data. + * @param hVfs The VFS handle to associate this VFS with. + * NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfs Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNew(PCRTVFSOPS pVfsOps, size_t cbInstance, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFS phVfs, void **ppvInstance); + + +/** + * Creates a new VFS base object handle. + * + * @returns IPRT status code + * @param pObjOps The base object operations. + * @param cbInstance The size of the instance data. + * @param hVfs The VFS handle to associate this base object + * with. NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfsObj Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewBaseObj(PCRTVFSOBJOPS pObjOps, size_t cbInstance, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFSOBJ phVfsObj, void **ppvInstance); + + +/** + * Additional operations for setting object attributes. + */ +typedef struct RTVFSOBJSETOPS +{ + /** The structure version (RTVFSOBJSETOPS_VERSION). */ + uint32_t uVersion; + /** The offset back to the RTVFSOBJOPS structure. */ + uint32_t offObjOps; + + /** + * Set the unix style owner and group. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param fMode The new mode bits. + * @param fMask The mask indicating which bits we are + * changing. + * @note Optional, failing with VERR_WRITE_PROTECT if NULL. + * @sa RTFileSetMode + */ + DECLCALLBACKMEMBER(int, pfnSetMode)(void *pvThis, RTFMODE fMode, RTFMODE fMask); + + /** + * Set the timestamps associated with the object. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param pAccessTime Pointer to the new access time. NULL if not + * to be changed. + * @param pModificationTime Pointer to the new modifcation time. NULL if + * not to be changed. + * @param pChangeTime Pointer to the new change time. NULL if not + * to be changed. + * @param pBirthTime Pointer to the new time of birth. NULL if + * not to be changed. + * @remarks See RTFileSetTimes for restrictions and behavior imposed by the + * host OS or underlying VFS provider. + * @note Optional, failing with VERR_WRITE_PROTECT if NULL. + * @sa RTFileSetTimes + */ + DECLCALLBACKMEMBER(int, pfnSetTimes)(void *pvThis, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime, + PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime); + + /** + * Set the unix style owner and group. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param uid The user ID of the new owner. NIL_RTUID if + * unchanged. + * @param gid The group ID of the new owner group. NIL_RTGID if + * unchanged. + * @note Optional, failing with VERR_WRITE_PROTECT if NULL. + * @sa RTFileSetOwner + */ + DECLCALLBACKMEMBER(int, pfnSetOwner)(void *pvThis, RTUID uid, RTGID gid); + + /** Marks the end of the structure (RTVFSOBJSETOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSOBJSETOPS; +/** Pointer to const object attribute setter operations. */ +typedef RTVFSOBJSETOPS const *PCRTVFSOBJSETOPS; + +/** The RTVFSOBJSETOPS structure version. */ +#define RTVFSOBJSETOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x2f,1,0) + + +/** + * The filesystem stream operations. + * + * @extends RTVFSOBJOPS + */ +typedef struct RTVFSFSSTREAMOPS +{ + /** The basic object operation. */ + RTVFSOBJOPS Obj; + /** The structure version (RTVFSFSSTREAMOPS_VERSION). */ + uint32_t uVersion; + /** Reserved field, MBZ. */ + uint32_t fReserved; + + /** + * Gets the next object in the stream. + * + * Readable streams only. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS if a new object was retrieved. + * @retval VERR_EOF when there are no more objects. + * @param pvThis The implementation specific directory data. + * @param ppszName Where to return the object name. Must be freed by + * calling RTStrFree. + * @param penmType Where to return the object type. + * @param phVfsObj Where to return the object handle (referenced). This + * must be cast to the desired type before use. + * @sa RTVfsFsStrmNext + * + * @note Setting this member to NULL is okay for write-only streams. + */ + DECLCALLBACKMEMBER(int, pfnNext)(void *pvThis, char **ppszName, RTVFSOBJTYPE *penmType, PRTVFSOBJ phVfsObj); + + /** + * Adds another object into the stream. + * + * Writable streams only. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszPath The path to the object. + * @param hVfsObj The object to add. + * @param fFlags Reserved for the future, MBZ. + * @sa RTVfsFsStrmAdd + * + * @note Setting this member to NULL is okay for read-only streams. + */ + DECLCALLBACKMEMBER(int, pfnAdd)(void *pvThis, const char *pszPath, RTVFSOBJ hVfsObj, uint32_t fFlags); + + /** + * Pushes an byte stream onto the stream (optional). + * + * Writable streams only. + * + * This differs from RTVFSFSSTREAMOPS::pfnAdd() in that it will create a regular + * file in the output file system stream and provide the actual content bytes + * via the returned I/O stream object. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszPath The path to the file. + * @param cbFile The file size. This can also be set to UINT64_MAX if + * the file system stream is backed by a file. + * @param paObjInfo Array of zero or more RTFSOBJINFO structures containing + * different pieces of information about the file. If any + * provided, the first one should be a RTFSOBJATTRADD_UNIX + * one, additional can be supplied if wanted. What exactly + * is needed depends on the underlying FS stream + * implementation. + * @param cObjInfo Number of items in the array @a paObjInfo points at. + * @param fFlags RTVFSFSSTRM_PUSH_F_XXX. + * @param phVfsIos Where to return the I/O stream to feed the file content + * to. If the FS stream is backed by a file, the returned + * handle can be cast to a file if necessary. + */ + DECLCALLBACKMEMBER(int, pfnPushFile)(void *pvThis, const char *pszPath, uint64_t cbFile, + PCRTFSOBJINFO paObjInfo, uint32_t cObjInfo, uint32_t fFlags, PRTVFSIOSTREAM phVfsIos); + + /** + * Marks the end of the stream. + * + * Writable streams only. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @sa RTVfsFsStrmEnd + * + * @note Setting this member to NULL is okay for read-only streams. + */ + DECLCALLBACKMEMBER(int, pfnEnd)(void *pvThis); + + /** Marks the end of the structure (RTVFSFSSTREAMOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSFSSTREAMOPS; +/** Pointer to const object attribute setter operations. */ +typedef RTVFSFSSTREAMOPS const *PCRTVFSFSSTREAMOPS; + +/** The RTVFSFSSTREAMOPS structure version. */ +#define RTVFSFSSTREAMOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x3f,2,0) + + +/** + * Creates a new VFS filesystem stream handle. + * + * @returns IPRT status code + * @param pFsStreamOps The filesystem stream operations. + * @param cbInstance The size of the instance data. + * @param hVfs The VFS handle to associate this filesystem + * stream with. NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param fReadOnly Set if read-only, clear if write-only. + * @param phVfsFss Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewFsStream(PCRTVFSFSSTREAMOPS pFsStreamOps, size_t cbInstance, RTVFS hVfs, RTVFSLOCK hLock, bool fReadOnly, + PRTVFSFSSTREAM phVfsFss, void **ppvInstance); + +/** + * Gets the private data of an filesystem stream. + * + * @returns Pointer to the private data. NULL if the handle is invalid in some + * way. + * @param hVfsFss The FS stream handle. + * @param pFsStreamOps The FS stream operations. This servers as a + * sort of password. + */ +RTDECL(void *) RTVfsFsStreamToPrivate(RTVFSFSSTREAM hVfsFss, PCRTVFSFSSTREAMOPS pFsStreamOps); + + +/** + * The directory operations. + * + * @extends RTVFSOBJOPS + * @extends RTVFSOBJSETOPS + */ +typedef struct RTVFSDIROPS +{ + /** The basic object operation. */ + RTVFSOBJOPS Obj; + /** The structure version (RTVFSDIROPS_VERSION). */ + uint32_t uVersion; + /** Reserved field, MBZ. */ + uint32_t fReserved; + /** The object setter operations. */ + RTVFSOBJSETOPS ObjSet; + + /** + * Generic method for opening any kind of file system object. + * + * Can also create files and directories. Symbolic links, devices and such + * needs to be created using special methods or this would end up being way more + * complicated than it already is. + * + * There are optional specializations available. + * + * @returns IPRT status code. + * @retval VERR_PATH_NOT_FOUND or VERR_FILE_NOT_FOUND if @a pszEntry was not + * found. + * @retval VERR_IS_A_FILE if @a pszEntry is a file or similar but @a fFlags + * indicates that the type of object should not be opened. + * @retval VERR_IS_A_DIRECTORY if @a pszEntry is a directory but @a fFlags + * indicates that directories should not be opened. + * @retval VERR_IS_A_SYMLINK if @a pszEntry is a symbolic link but @a fFlags + * indicates that symbolic links should not be opened (or followed). + * @retval VERR_IS_A_FIFO if @a pszEntry is a FIFO but @a fFlags indicates that + * FIFOs should not be opened. + * @retval VERR_IS_A_SOCKET if @a pszEntry is a socket but @a fFlags indicates + * that sockets should not be opened. + * @retval VERR_IS_A_BLOCK_DEVICE if @a pszEntry is a block device but + * @a fFlags indicates that block devices should not be opened, or vice + * versa. + * + * @param pvThis The implementation specific directory data. + * @param pszEntry The name of the immediate file to open or create. + * @param fOpenFile RTFILE_O_XXX combination. + * @param fObjFlags More flags: RTVFSOBJ_F_XXX, RTPATH_F_XXX. + * The meaning of RTPATH_F_FOLLOW_LINK differs here, if + * @a pszEntry is a symlink it should be opened for + * traversal rather than according to @a fOpenFile. + * @param phVfsObj Where to return the handle to the opened object. + * @sa RTFileOpen, RTDirOpen + */ + DECLCALLBACKMEMBER(int, pfnOpen)(void *pvThis, const char *pszEntry, uint64_t fOpenFile, + uint32_t fObjFlags, PRTVFSOBJ phVfsObj); + + /** + * Optional method for symbolic link handling in the vfsstddir.cpp. + * + * This is really just a hack to make symbolic link handling work when working + * with directory objects that doesn't have an associated VFS. It also helps + * deal with drive letters in symbolic links on Windows and OS/2. + * + * @returns IPRT status code. + * @retval VERR_PATH_IS_RELATIVE if @a pszPath isn't absolute and should be + * handled using pfnOpen(). + * + * @param pvThis The implementation specific directory data. + * @param pszRoot Path to the alleged root. + * @param phVfsDir Where to return the handle to the specified root + * directory (or may current dir on a drive letter). + */ + DECLCALLBACKMEMBER(int, pfnFollowAbsoluteSymlink)(void *pvThis, const char *pszRoot, PRTVFSDIR phVfsDir); + + /** + * Open or create a file. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszFilename The name of the immediate file to open or create. + * @param fOpen The open flags (RTFILE_O_XXX). + * @param phVfsFile Where to return the handle to the opened file. + * @note Optional. RTVFSDIROPS::pfnOpenObj will be used if NULL. + * @sa RTFileOpen. + */ + DECLCALLBACKMEMBER(int, pfnOpenFile)(void *pvThis, const char *pszFilename, uint64_t fOpen, PRTVFSFILE phVfsFile); + + /** + * Open an existing subdirectory. + * + * @returns IPRT status code. + * @retval VERR_IS_A_SYMLINK if @a pszSubDir is a symbolic link. + * @retval VERR_NOT_A_DIRECTORY is okay for symbolic links too. + * + * @param pvThis The implementation specific directory data. + * @param pszSubDir The name of the immediate subdirectory to open. + * @param fFlags RTDIR_F_XXX. + * @param phVfsDir Where to return the handle to the opened directory. + * Optional. + * @note Optional. RTVFSDIROPS::pfnOpenObj will be used if NULL. + * @sa RTDirOpen. + */ + DECLCALLBACKMEMBER(int, pfnOpenDir)(void *pvThis, const char *pszSubDir, uint32_t fFlags, PRTVFSDIR phVfsDir); + + /** + * Creates a new subdirectory. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszSubDir The name of the immediate subdirectory to create. + * @param fMode The mode mask of the new directory. + * @param phVfsDir Where to optionally return the handle to the newly + * create directory. + * @note Optional. RTVFSDIROPS::pfnOpenObj will be used if NULL. + * @sa RTDirCreate. + */ + DECLCALLBACKMEMBER(int, pfnCreateDir)(void *pvThis, const char *pszSubDir, RTFMODE fMode, PRTVFSDIR phVfsDir); + + /** + * Opens an existing symbolic link. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszSymlink The name of the immediate symbolic link to open. + * @param phVfsSymlink Where to optionally return the handle to the + * newly create symbolic link. + * @note Optional. RTVFSDIROPS::pfnOpenObj will be used if NULL. + * @sa RTSymlinkCreate. + */ + DECLCALLBACKMEMBER(int, pfnOpenSymlink)(void *pvThis, const char *pszSymlink, PRTVFSSYMLINK phVfsSymlink); + + /** + * Creates a new symbolic link. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszSymlink The name of the immediate symbolic link to create. + * @param pszTarget The symbolic link target. + * @param enmType The symbolic link type. + * @param phVfsSymlink Where to optionally return the handle to the + * newly create symbolic link. + * @sa RTSymlinkCreate. + */ + DECLCALLBACKMEMBER(int, pfnCreateSymlink)(void *pvThis, const char *pszSymlink, const char *pszTarget, + RTSYMLINKTYPE enmType, PRTVFSSYMLINK phVfsSymlink); + + /** + * Query information about an entry. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszEntry The name of the directory entry to remove. + * @param pObjInfo Where to return the info on success. + * @param enmAddAttr Which set of additional attributes to request. + * @note Optional. RTVFSDIROPS::pfnOpenObj and RTVFSOBJOPS::pfnQueryInfo + * will be used if NULL. + * @sa RTPathQueryInfo, RTVFSOBJOPS::pfnQueryInfo + */ + DECLCALLBACKMEMBER(int, pfnQueryEntryInfo)(void *pvThis, const char *pszEntry, + PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAddAttr); + + /** + * Removes a directory entry. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszEntry The name of the directory entry to remove. + * @param fType If non-zero, this restricts the type of the entry to + * the object type indicated by the mask + * (RTFS_TYPE_XXX). + * @sa RTFileRemove, RTDirRemove, RTSymlinkRemove. + */ + DECLCALLBACKMEMBER(int, pfnUnlinkEntry)(void *pvThis, const char *pszEntry, RTFMODE fType); + + /** + * Renames a directory entry. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pszEntry The name of the directory entry to rename. + * @param fType If non-zero, this restricts the type of the entry to + * the object type indicated by the mask + * (RTFS_TYPE_XXX). + * @param pszNewName The new entry name. + * @sa RTPathRename + * + * @todo This API is not flexible enough, must be able to rename between + * directories within a file system. + */ + DECLCALLBACKMEMBER(int, pfnRenameEntry)(void *pvThis, const char *pszEntry, RTFMODE fType, const char *pszNewName); + + /** + * Rewind the directory stream so that the next read returns the first + * entry. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + */ + DECLCALLBACKMEMBER(int, pfnRewindDir)(void *pvThis); + + /** + * Rewind the directory stream so that the next read returns the first + * entry. + * + * @returns IPRT status code. + * @param pvThis The implementation specific directory data. + * @param pDirEntry Output buffer. + * @param pcbDirEntry Complicated, see RTDirReadEx. + * @param enmAddAttr Which set of additional attributes to request. + * @sa RTDirReadEx + */ + DECLCALLBACKMEMBER(int, pfnReadDir)(void *pvThis, PRTDIRENTRYEX pDirEntry, size_t *pcbDirEntry, RTFSOBJATTRADD enmAddAttr); + + /** Marks the end of the structure (RTVFSDIROPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSDIROPS; +/** Pointer to const directory operations. */ +typedef RTVFSDIROPS const *PCRTVFSDIROPS; +/** The RTVFSDIROPS structure version. */ +#define RTVFSDIROPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x4f,1,0) + + +/** + * Creates a new VFS directory handle. + * + * @returns IPRT status code + * @param pDirOps The directory operations. + * @param cbInstance The size of the instance data. + * @param fFlags RTVFSDIR_F_XXX + * @param hVfs The VFS handle to associate this directory with. + * NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfsDir Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewDir(PCRTVFSDIROPS pDirOps, size_t cbInstance, uint32_t fFlags, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFSDIR phVfsDir, void **ppvInstance); + +/** @name RTVFSDIR_F_XXX + * @{ */ +/** Don't reference the @a hVfs parameter passed to RTVfsNewDir. + * This is a permanent root directory hack. */ +#define RTVFSDIR_F_NO_VFS_REF RT_BIT_32(0) +/** @} */ + +/** + * Gets the private data of a directory. + * + * @returns Pointer to the private data. NULL if the handle is invalid in some + * way. + * @param hVfsDir The directory handle. + * @param pDirOps The directory operations. This servers as a + * sort of password. + */ +RTDECL(void *) RTVfsDirToPrivate(RTVFSDIR hVfsDir, PCRTVFSDIROPS pDirOps); + + +/** + * The symbolic link operations. + * + * @extends RTVFSOBJOPS + * @extends RTVFSOBJSETOPS + */ +typedef struct RTVFSSYMLINKOPS +{ + /** The basic object operation. */ + RTVFSOBJOPS Obj; + /** The structure version (RTVFSSYMLINKOPS_VERSION). */ + uint32_t uVersion; + /** Reserved field, MBZ. */ + uint32_t fReserved; + /** The object setter operations. */ + RTVFSOBJSETOPS ObjSet; + + /** + * Read the symbolic link target. + * + * @returns IPRT status code. + * @param pvThis The implementation specific symbolic link data. + * @param pszTarget The target buffer. + * @param cbTarget The size of the target buffer. + * @sa RTSymlinkRead + */ + DECLCALLBACKMEMBER(int, pfnRead)(void *pvThis, char *pszTarget, size_t cbTarget); + + /** Marks the end of the structure (RTVFSSYMLINKOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSSYMLINKOPS; +/** Pointer to const symbolic link operations. */ +typedef RTVFSSYMLINKOPS const *PCRTVFSSYMLINKOPS; +/** The RTVFSSYMLINKOPS structure version. */ +#define RTVFSSYMLINKOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x5f,1,0) + + +/** + * Creates a new VFS symlink handle. + * + * @returns IPRT status code + * @param pSymlinkOps The symlink operations. + * @param cbInstance The size of the instance data. + * @param hVfs The VFS handle to associate this symlink object + * with. NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfsSym Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewSymlink(PCRTVFSSYMLINKOPS pSymlinkOps, size_t cbInstance, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFSSYMLINK phVfsSym, void **ppvInstance); + + +/** + * The basis for all I/O objects (files, pipes, sockets, devices, ++). + * + * @extends RTVFSOBJOPS + */ +typedef struct RTVFSIOSTREAMOPS +{ + /** The basic object operation. */ + RTVFSOBJOPS Obj; + /** The structure version (RTVFSIOSTREAMOPS_VERSION). */ + uint32_t uVersion; + /** Feature field. */ + uint32_t fFeatures; + + /** + * Reads from the file/stream. + * + * @returns IPRT status code. See RTVfsIoStrmRead. + * @param pvThis The implementation specific file data. + * @param off Where to read at, -1 for the current position. + * @param pSgBuf Gather buffer describing the bytes that are to be + * written. + * @param fBlocking If @c true, the call is blocking, if @c false it + * should not block. + * @param pcbRead Where return the number of bytes actually read. + * This is set it 0 by the caller. If NULL, try read + * all and fail if incomplete. + * @sa RTVfsIoStrmRead, RTVfsIoStrmSgRead, RTVfsFileRead, + * RTVfsFileReadAt, RTFileRead, RTFileReadAt. + */ + DECLCALLBACKMEMBER(int, pfnRead)(void *pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbRead); + + /** + * Writes to the file/stream. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param off Where to start wrinting, -1 for the current + * position. + * @param pSgBuf Gather buffers describing the bytes that are to be + * written. + * @param fBlocking If @c true, the call is blocking, if @c false it + * should not block. + * @param pcbWritten Where to return the number of bytes actually + * written. This is set it 0 by the caller. If + * NULL, try write it all and fail if incomplete. + * @note Optional, failing with VERR_WRITE_PROTECT if NULL. + * @sa RTFileWrite, RTFileWriteAt. + */ + DECLCALLBACKMEMBER(int, pfnWrite)(void *pvThis, RTFOFF off, PCRTSGBUF pSgBuf, bool fBlocking, size_t *pcbWritten); + + /** + * Flushes any pending data writes to the stream. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @sa RTFileFlush. + */ + DECLCALLBACKMEMBER(int, pfnFlush)(void *pvThis); + + /** + * Poll for events. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param fEvents The events to poll for (RTPOLL_EVT_XXX). + * @param cMillies How long to wait for event to eventuate. + * @param fIntr Whether the wait is interruptible and can return + * VERR_INTERRUPTED (@c true) or if this condition + * should be hidden from the caller (@c false). + * @param pfRetEvents Where to return the event mask. + * @note Optional. If NULL, immediately return all requested non-error + * events, waiting for errors works like sleep. + * @sa RTPollSetAdd, RTPoll, RTPollNoResume. + */ + DECLCALLBACKMEMBER(int, pfnPollOne)(void *pvThis, uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr, + uint32_t *pfRetEvents); + + /** + * Tells the current file/stream position. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param poffActual Where to return the actual offset. + * @sa RTFileTell + */ + DECLCALLBACKMEMBER(int, pfnTell)(void *pvThis, PRTFOFF poffActual); + + /** + * Skips @a cb ahead in the stream. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param cb The number bytes to skip. + * @remarks This is optional and can be NULL. + */ + DECLCALLBACKMEMBER(int, pfnSkip)(void *pvThis, RTFOFF cb); + + /** + * Fills the stream with @a cb zeros. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param cb The number of zero bytes to insert. + * @remarks This is optional and can be NULL. + */ + DECLCALLBACKMEMBER(int, pfnZeroFill)(void *pvThis, RTFOFF cb); + + /** Marks the end of the structure (RTVFSIOSTREAMOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSIOSTREAMOPS; +/** Pointer to const I/O stream operations. */ +typedef RTVFSIOSTREAMOPS const *PCRTVFSIOSTREAMOPS; + +/** The RTVFSIOSTREAMOPS structure version. */ +#define RTVFSIOSTREAMOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x6f,1,0) + +/** @name RTVFSIOSTREAMOPS::fFeatures + * @{ */ +/** No scatter gather lists, thank you. */ +#define RTVFSIOSTREAMOPS_FEAT_NO_SG RT_BIT_32(0) +/** Mask of the valid I/O stream feature flags. */ +#define RTVFSIOSTREAMOPS_FEAT_VALID_MASK UINT32_C(0x00000001) +/** @} */ + + +/** + * Creates a new VFS I/O stream handle. + * + * @returns IPRT status code + * @param pIoStreamOps The I/O stream operations. + * @param cbInstance The size of the instance data. + * @param fOpen The open flags. The minimum is the access mask. + * @param hVfs The VFS handle to associate this I/O stream + * with. NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfsIos Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewIoStream(PCRTVFSIOSTREAMOPS pIoStreamOps, size_t cbInstance, uint32_t fOpen, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFSIOSTREAM phVfsIos, void **ppvInstance); + + +/** + * Gets the private data of an I/O stream. + * + * @returns Pointer to the private data. NULL if the handle is invalid in some + * way. + * @param hVfsIos The I/O stream handle. + * @param pIoStreamOps The I/O stream operations. This servers as a + * sort of password. + */ +RTDECL(void *) RTVfsIoStreamToPrivate(RTVFSIOSTREAM hVfsIos, PCRTVFSIOSTREAMOPS pIoStreamOps); + + +/** + * The file operations. + * + * @extends RTVFSIOSTREAMOPS + * @extends RTVFSOBJSETOPS + */ +typedef struct RTVFSFILEOPS +{ + /** The I/O stream and basis object operations. */ + RTVFSIOSTREAMOPS Stream; + /** The structure version (RTVFSFILEOPS_VERSION). */ + uint32_t uVersion; + /** Reserved field, MBZ. */ + uint32_t fReserved; + /** The object setter operations. */ + RTVFSOBJSETOPS ObjSet; + + /** + * Changes the current file position. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param offSeek The offset to seek. + * @param uMethod The seek method, i.e. what the seek is relative to. + * @param poffActual Where to return the actual offset. + * @sa RTFileSeek + */ + DECLCALLBACKMEMBER(int, pfnSeek)(void *pvThis, RTFOFF offSeek, unsigned uMethod, PRTFOFF poffActual); + + /** + * Get the current file size. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param pcbFile Where to store the current file size. + * @sa RTFileQuerySize + */ + DECLCALLBACKMEMBER(int, pfnQuerySize)(void *pvThis, uint64_t *pcbFile); + + /** + * Change the file size. + * + * @returns IPRT status code. + * @retval VERR_ACCESS_DENIED if handle isn't writable. + * @retval VERR_WRITE_PROTECT if read-only file system. + * @retval VERR_FILE_TOO_BIG if cbSize is larger than what the file system can + * theoretically deal with. + * @retval VERR_DISK_FULL if the file system if full. + * @retval VERR_NOT_SUPPORTED if fFlags indicates some operation that's not + * supported by the file system / host operating system. + * + * @param pvThis The implementation specific file data. + * @param pcbFile Where to store the current file size. + * @param fFlags RTVFSFILE_SET_SIZE_F_XXX. + * @note Optional. If NULL, VERR_WRITE_PROTECT will be returned. + * @sa RTFileSetSize, RTFileSetAllocationSize + */ + DECLCALLBACKMEMBER(int, pfnSetSize)(void *pvThis, uint64_t cbFile, uint32_t fFlags); + + /** + * Determine the maximum file size. + * + * This won't take amount of freespace into account, just the limitations of the + * underlying file system / host operating system. + * + * @returns IPRT status code. + * @param pvThis The implementation specific file data. + * @param pcbMax Where to return the max file size. + * @note Optional. If NULL, VERR_NOT_IMPLEMENTED will be returned. + * @sa RTFileQueryMaxSizeEx + */ + DECLCALLBACKMEMBER(int, pfnQueryMaxSize)(void *pvThis, uint64_t *pcbMax); + + /** @todo There will be more methods here. */ + + /** Marks the end of the structure (RTVFSFILEOPS_VERSION). */ + uintptr_t uEndMarker; +} RTVFSFILEOPS; +/** Pointer to const file operations. */ +typedef RTVFSFILEOPS const *PCRTVFSFILEOPS; + +/** The RTVFSFILEOPS structure version. */ +#define RTVFSFILEOPS_VERSION RT_MAKE_U32_FROM_U8(0xff,0x7f,2,0) + +/** + * Creates a new VFS file handle. + * + * @returns IPRT status code + * @param pFileOps The file operations. + * @param cbInstance The size of the instance data. + * @param fOpen The open flags. The minimum is the access mask. + * @param hVfs The VFS handle to associate this file with. + * NIL_VFS is ok. + * @param hLock Handle to a custom lock to be used with the new + * object. The reference is consumed. NIL and + * special lock handles are fine. + * @param phVfsFile Where to return the new handle. + * @param ppvInstance Where to return the pointer to the instance data + * (size is @a cbInstance). + */ +RTDECL(int) RTVfsNewFile(PCRTVFSFILEOPS pFileOps, size_t cbInstance, uint32_t fOpen, RTVFS hVfs, RTVFSLOCK hLock, + PRTVFSFILE phVfsFile, void **ppvInstance); + + +/** @defgroup grp_rt_vfs_ll_util VFS Utility APIs + * @{ */ + +/** + * Parsed path. + */ +typedef struct RTVFSPARSEDPATH +{ + /** The length of the path in szCopy. */ + uint16_t cch; + /** The number of path components. */ + uint16_t cComponents; + /** Set if the path ends with slash, indicating that it's a directory + * reference and not a file reference. The slash has been removed from + * the copy. */ + bool fDirSlash; + /** Set if absolute. */ + bool fAbsolute; + /** The offset where each path component starts, i.e. the char after the + * slash. The array has cComponents + 1 entries, where the final one is + * cch + 1 so that one can always terminate the current component by + * szPath[aoffComponent[i] - 1] = '\0'. */ + uint16_t aoffComponents[RTPATH_MAX / 2 + 1]; + /** A normalized copy of the path. + * Reserve some extra space so we can be more relaxed about overflow + * checks and terminator paddings, especially when recursing. */ + char szPath[RTPATH_MAX]; +} RTVFSPARSEDPATH; +/** Pointer to a parsed path. */ +typedef RTVFSPARSEDPATH *PRTVFSPARSEDPATH; + +/** The max accepted path length. + * This must be a few chars shorter than RTVFSPARSEDPATH::szPath because we + * use two terminators and wish be a little bit lazy with checking. */ +#define RTVFSPARSEDPATH_MAX (RTPATH_MAX - 4) + +/** + * Appends @a pszPath (relative) to the already parsed path @a pPath. + * + * @retval VINF_SUCCESS + * @retval VERR_FILENAME_TOO_LONG + * @retval VERR_INTERNAL_ERROR_4 + * @param pPath The parsed path to append @a pszPath onto. + * This is both input and output. + * @param pszPath The path to append. This must be relative. + * @param piRestartComp The component to restart parsing at. This is + * input/output. The input does not have to be + * within the valid range. Optional. + */ +RTDECL(int) RTVfsParsePathAppend(PRTVFSPARSEDPATH pPath, const char *pszPath, uint16_t *piRestartComp); + +/** + * Parses a path. + * + * @retval VINF_SUCCESS + * @retval VERR_FILENAME_TOO_LONG + * @param pPath Where to store the parsed path. + * @param pszPath The path to parse. Absolute or relative to @a + * pszCwd. + * @param pszCwd The current working directory. Must be + * absolute. + */ +RTDECL(int) RTVfsParsePath(PRTVFSPARSEDPATH pPath, const char *pszPath, const char *pszCwd); + +/** + * Same as RTVfsParsePath except that it allocates a temporary buffer. + * + * @retval VINF_SUCCESS + * @retval VERR_NO_TMP_MEMORY + * @retval VERR_FILENAME_TOO_LONG + * @param pszPath The path to parse. Absolute or relative to @a + * pszCwd. + * @param pszCwd The current working directory. Must be + * absolute. + * @param ppPath Where to store the pointer to the allocated + * buffer containing the parsed path. This must + * be freed by calling RTVfsParsePathFree. NULL + * will be stored on failured. + */ +RTDECL(int) RTVfsParsePathA(const char *pszPath, const char *pszCwd, PRTVFSPARSEDPATH *ppPath); + +/** + * Frees a buffer returned by RTVfsParsePathA. + * + * @param pPath The parsed path buffer to free. NULL is fine. + */ +RTDECL(void) RTVfsParsePathFree(PRTVFSPARSEDPATH pPath); + +/** + * Dummy implementation of RTVFSIOSTREAMOPS::pfnPollOne. + * + * This handles the case where there is no chance any events my be raised and + * all that is required is to wait according to the parameters. + * + * @returns IPRT status code. + * @param fEvents The events to poll for (RTPOLL_EVT_XXX). + * @param cMillies How long to wait for event to eventuate. + * @param fIntr Whether the wait is interruptible and can return + * VERR_INTERRUPTED (@c true) or if this condition + * should be hidden from the caller (@c false). + * @param pfRetEvents Where to return the event mask. + * @sa RTVFSIOSTREAMOPS::pfnPollOne, RTPollSetAdd, RTPoll, RTPollNoResume. + */ +RTDECL(int) RTVfsUtilDummyPollOne(uint32_t fEvents, RTMSINTERVAL cMillies, bool fIntr, uint32_t *pfRetEvents); + +/** @} */ + + +/** @defgroup grp_rt_vfs_lowlevel_chain VFS Chains (Low Level) + * @ref grp_rt_vfs_chain + * @{ + */ + +/** Pointer to a VFS chain element registration record. */ +typedef struct RTVFSCHAINELEMENTREG *PRTVFSCHAINELEMENTREG; +/** Pointer to a const VFS chain element registration record. */ +typedef struct RTVFSCHAINELEMENTREG const *PCRTVFSCHAINELEMENTREG; + +/** + * VFS chain element argument. + */ +typedef struct RTVFSCHAINELEMENTARG +{ + /** The string argument value. */ + char *psz; + /** The specification offset of this argument. */ + uint16_t offSpec; + /** Provider specific value. */ + uint64_t uProvider; +} RTVFSCHAINELEMENTARG; +/** Pointer to a VFS chain element argument. */ +typedef RTVFSCHAINELEMENTARG *PRTVFSCHAINELEMENTARG; + + +/** + * VFS chain element specification. + */ +typedef struct RTVFSCHAINELEMSPEC +{ + /** The provider name. + * This can be NULL if this is the final component and it's just a path. */ + char *pszProvider; + /** The input type, RTVFSOBJTYPE_INVALID if first. */ + RTVFSOBJTYPE enmTypeIn; + /** The element type. + * RTVFSOBJTYPE_END if this is the final component and it's just a path. */ + RTVFSOBJTYPE enmType; + /** The input spec offset of this element. */ + uint16_t offSpec; + /** The length of the input spec. */ + uint16_t cchSpec; + /** The number of arguments. */ + uint32_t cArgs; + /** Arguments. */ + PRTVFSCHAINELEMENTARG paArgs; + + /** The provider. */ + PCRTVFSCHAINELEMENTREG pProvider; + /** Provider specific value. */ + uint64_t uProvider; + /** The object (with reference). */ + RTVFSOBJ hVfsObj; +} RTVFSCHAINELEMSPEC; +/** Pointer to a chain element specification. */ +typedef RTVFSCHAINELEMSPEC *PRTVFSCHAINELEMSPEC; +/** Pointer to a const chain element specification. */ +typedef RTVFSCHAINELEMSPEC const *PCRTVFSCHAINELEMSPEC; + + +/** + * Parsed VFS chain specification. + */ +typedef struct RTVFSCHAINSPEC +{ + /** Open directory flags (RTFILE_O_XXX). */ + uint64_t fOpenFile; + /** To be defined. */ + uint32_t fOpenDir; + /** The type desired by the caller. */ + RTVFSOBJTYPE enmDesiredType; + /** The number of elements. */ + uint32_t cElements; + /** The elements. */ + PRTVFSCHAINELEMSPEC paElements; +} RTVFSCHAINSPEC; +/** Pointer to a parsed VFS chain specification. */ +typedef RTVFSCHAINSPEC *PRTVFSCHAINSPEC; +/** Pointer to a const, parsed VFS chain specification. */ +typedef RTVFSCHAINSPEC const *PCRTVFSCHAINSPEC; + + +/** + * A chain element provider registration record. + */ +typedef struct RTVFSCHAINELEMENTREG +{ + /** The version (RTVFSCHAINELEMENTREG_VERSION). */ + uint32_t uVersion; + /** Reserved, MBZ. */ + uint32_t fReserved; + /** The provider name (unique). */ + const char *pszName; + /** For chaining the providers. */ + RTLISTNODE ListEntry; + /** Help text. */ + const char *pszHelp; + + /** + * Checks the element specification. + * + * This is allowed to parse arguments and use pSpec->uProvider and + * pElement->paArgs[].uProvider to store information that pfnInstantiate and + * pfnCanReuseElement may use later on, thus avoiding duplicating work/code. + * + * @returns IPRT status code. + * @param pProviderReg Pointer to the element provider registration. + * @param pSpec The chain specification. + * @param pElement The chain element specification to validate. + * @param poffError Where to return error offset on failure. This is + * set to the pElement->offSpec on input, so it only + * needs to be adjusted if an argument is at fault. + * @param pErrInfo Where to return additional error information, if + * available. Optional. + */ + DECLCALLBACKMEMBER(int, pfnValidate)(PCRTVFSCHAINELEMENTREG pProviderReg, PRTVFSCHAINSPEC pSpec, + PRTVFSCHAINELEMSPEC pElement, uint32_t *poffError, PRTERRINFO pErrInfo); + + /** + * Create a VFS object according to the element specification. + * + * @returns IPRT status code. + * @param pProviderReg Pointer to the element provider registration. + * @param pSpec The chain specification. + * @param pElement The chain element specification to instantiate. + * @param hPrevVfsObj Handle to the previous VFS object, NIL_RTVFSOBJ if + * first. + * @param phVfsObj Where to return the VFS object handle. + * @param poffError Where to return error offset on failure. This is + * set to the pElement->offSpec on input, so it only + * needs to be adjusted if an argument is at fault. + * @param pErrInfo Where to return additional error information, if + * available. Optional. + */ + DECLCALLBACKMEMBER(int, pfnInstantiate)(PCRTVFSCHAINELEMENTREG pProviderReg, PCRTVFSCHAINSPEC pSpec, + PCRTVFSCHAINELEMSPEC pElement, RTVFSOBJ hPrevVfsObj, + PRTVFSOBJ phVfsObj, uint32_t *poffError, PRTERRINFO pErrInfo); + + /** + * Determins whether the element can be reused. + * + * This is for handling situations accessing the same file system twice, like + * for both the source and destiation of a copy operation. This allows not only + * sharing resources and avoid doing things twice, but also helps avoid file + * sharing violations and inconsistencies araising from the image being updated + * and read independently. + * + * @returns true if the element from @a pReuseSpec an be reused, false if not. + * @param pProviderReg Pointer to the element provider registration. + * @param pSpec The chain specification. + * @param pElement The chain element specification. + * @param pReuseSpec The chain specification of the existing chain. + * @param pReuseElement The chain element specification of the existing + * element that is being considered for reuse. + */ + DECLCALLBACKMEMBER(bool, pfnCanReuseElement)(PCRTVFSCHAINELEMENTREG pProviderReg, + PCRTVFSCHAINSPEC pSpec, PCRTVFSCHAINELEMSPEC pElement, + PCRTVFSCHAINSPEC pReuseSpec, PCRTVFSCHAINELEMSPEC pReuseElement); + + /** End marker (RTVFSCHAINELEMENTREG_VERSION). */ + uintptr_t uEndMarker; +} RTVFSCHAINELEMENTREG; + +/** The VFS chain element registration record version number. */ +#define RTVFSCHAINELEMENTREG_VERSION RT_MAKE_U32_FROM_U8(0xff, 0x7f, 1, 0) + + +/** + * Parses the specification. + * + * @returns IPRT status code. + * @param pszSpec The specification string to parse. + * @param fFlags Flags, see RTVFSCHAIN_PF_XXX. + * @param enmDesiredType The object type the caller wants to interface with. + * @param ppSpec Where to return the pointer to the parsed + * specification. This must be freed by calling + * RTVfsChainSpecFree. Will always be set (unless + * invalid parameters.) + * @param poffError Where to return the offset into the input + * specification of what's causing trouble. Always + * set, unless this argument causes an invalid pointer + * error. + */ +RTDECL(int) RTVfsChainSpecParse(const char *pszSpec, uint32_t fFlags, RTVFSOBJTYPE enmDesiredType, + PRTVFSCHAINSPEC *ppSpec, uint32_t *poffError); + +/** @name RTVfsChainSpecParse + * @{ */ +/** Mask of valid flags. */ +#define RTVFSCHAIN_PF_VALID_MASK UINT32_C(0x00000000) +/** @} */ + +/** + * Checks and setups the chain. + * + * @returns IPRT status code. + * @param pSpec The parsed specification. + * @param pReuseSpec Spec to reuse if applicable. Optional. + * @param phVfsObj Where to return the VFS object. + * @param ppszFinalPath Where to return the pointer to the final path if + * applicable. The caller needs to check whether this + * is NULL or a path, in the former case nothing more + * needs doing, whereas in the latter the caller must + * perform the desired operation(s) on *phVfsObj using + * the final path. + * @param poffError Where to return the offset into the input + * specification of what's causing trouble. Always + * set, unless this argument causes an invalid pointer + * error. + * @param pErrInfo Where to return additional error information, if + * available. Optional. + */ +RTDECL(int) RTVfsChainSpecCheckAndSetup(PRTVFSCHAINSPEC pSpec, PCRTVFSCHAINSPEC pReuseSpec, + PRTVFSOBJ phVfsObj, const char **ppszFinalPath, uint32_t *poffError, PRTERRINFO pErrInfo); + +/** + * Frees a parsed chain specification. + * + * @param pSpec What RTVfsChainSpecParse returned. NULL is + * quietly ignored. + */ +RTDECL(void) RTVfsChainSpecFree(PRTVFSCHAINSPEC pSpec); + +/** + * Registers a chain element provider. + * + * @returns IPRT status code + * @param pRegRec The registration record. + * @param fFromCtor Indicates where we're called from. + */ +RTDECL(int) RTVfsChainElementRegisterProvider(PRTVFSCHAINELEMENTREG pRegRec, bool fFromCtor); + +/** + * Deregisters a chain element provider. + * + * @returns IPRT status code + * @param pRegRec The registration record. + * @param fFromDtor Indicates where we're called from. + */ +RTDECL(int) RTVfsChainElementDeregisterProvider(PRTVFSCHAINELEMENTREG pRegRec, bool fFromDtor); + + +/** @def RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER + * Automatically registers a chain element provider using a global constructor + * and destructor hack. + * + * @param pRegRec Pointer to the registration record. + * @param name Some unique variable name prefix. + */ + +#ifdef __cplusplus +/** + * Class used for registering a VFS chain element provider. + */ +class RTVfsChainElementAutoRegisterHack +{ +private: + /** The registration record, NULL if registration failed. */ + PRTVFSCHAINELEMENTREG m_pRegRec; + +public: + RTVfsChainElementAutoRegisterHack(PRTVFSCHAINELEMENTREG a_pRegRec) + : m_pRegRec(a_pRegRec) + { + int rc = RTVfsChainElementRegisterProvider(m_pRegRec, true); + if (RT_FAILURE(rc)) + m_pRegRec = NULL; + } + + ~RTVfsChainElementAutoRegisterHack() + { + RTVfsChainElementDeregisterProvider(m_pRegRec, true); + m_pRegRec = NULL; + } +}; + +# define RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER(pRegRec, name) \ + static RTVfsChainElementAutoRegisterHack name ## AutoRegistrationHack(pRegRec) + +#else +# define RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER(pRegRec, name) \ + extern void *name ## AutoRegistrationHack = \ + &Sorry_but_RTVFSCHAIN_AUTO_REGISTER_ELEMENT_PROVIDER_does_not_work_in_c_source_files +#endif + + +/** + * Common worker for the 'stdfile' and 'open' providers for implementing + * RTVFSCHAINELEMENTREG::pfnValidate. + * + * Stores the RTFILE_O_XXX flags in pSpec->uProvider. + * + * @returns IPRT status code. + * @param pSpec The chain specification. + * @param pElement The chain element specification to validate. + * @param poffError Where to return error offset on failure. This is set to + * the pElement->offSpec on input, so it only needs to be + * adjusted if an argument is at fault. + * @param pErrInfo Where to return additional error information, if + * available. Optional. + */ +RTDECL(int) RTVfsChainValidateOpenFileOrIoStream(PRTVFSCHAINSPEC pSpec, PRTVFSCHAINELEMSPEC pElement, + uint32_t *poffError, PRTERRINFO pErrInfo); + + +/** @} */ + + +/** @} */ + +RT_C_DECLS_END + +#endif /* !IPRT_INCLUDED_vfslowlevel_h */ + |