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| -rw-r--r-- | include/iprt/file.h | 1560 |
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diff --git a/include/iprt/file.h b/include/iprt/file.h new file mode 100644 index 00000000..5915fec0 --- /dev/null +++ b/include/iprt/file.h @@ -0,0 +1,1560 @@ +/** @file + * IPRT - File I/O. + */ + +/* + * Copyright (C) 2006-2019 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_file_h +#define IPRT_INCLUDED_file_h +#ifndef RT_WITHOUT_PRAGMA_ONCE +# pragma once +#endif + +#include <iprt/cdefs.h> +#include <iprt/types.h> +#include <iprt/stdarg.h> +#include <iprt/fs.h> +#include <iprt/sg.h> + +RT_C_DECLS_BEGIN + +/** @defgroup grp_rt_fileio RTFile - File I/O + * @ingroup grp_rt + * @{ + */ + +/** Platform specific text line break. + * @deprecated Use text I/O streams and '\\n'. See iprt/stream.h. */ +#if defined(RT_OS_OS2) || defined(RT_OS_WINDOWS) +# define RTFILE_LINEFEED "\r\n" +#else +# define RTFILE_LINEFEED "\n" +#endif + +/** Platform specific native standard input "handle". */ +#ifdef RT_OS_WINDOWS +# define RTFILE_NATIVE_STDIN ((uint32_t)-10) +#else +# define RTFILE_NATIVE_STDIN 0 +#endif + +/** Platform specific native standard out "handle". */ +#ifdef RT_OS_WINDOWS +# define RTFILE_NATIVE_STDOUT ((uint32_t)-11) +#else +# define RTFILE_NATIVE_STDOUT 1 +#endif + +/** Platform specific native standard error "handle". */ +#ifdef RT_OS_WINDOWS +# define RTFILE_NATIVE_STDERR ((uint32_t)-12) +#else +# define RTFILE_NATIVE_STDERR 2 +#endif + + +/** + * Checks if the specified file name exists and is a regular file. + * + * Symbolic links will be resolved. + * + * @returns true if it's a regular file, false if it isn't. + * @param pszPath The path to the file. + * + * @sa RTDirExists, RTPathExists, RTSymlinkExists. + */ +RTDECL(bool) RTFileExists(const char *pszPath); + +/** + * Queries the size of a file, given the path to it. + * + * Symbolic links will be resolved. + * + * @returns IPRT status code. + * @param pszPath The path to the file. + * @param pcbFile Where to return the file size (bytes). + * + * @sa RTFileGetSize, RTPathQueryInfoEx. + */ +RTDECL(int) RTFileQuerySize(const char *pszPath, uint64_t *pcbFile); + + +/** @name Open flags + * @{ */ +/** Attribute access only. + * @remarks Only accepted on windows, requires RTFILE_O_ACCESS_ATTR_MASK + * to yield a non-zero result. Otherwise, this is invalid. */ +#define RTFILE_O_ATTR_ONLY UINT32_C(0x00000000) +/** Open the file with read access. */ +#define RTFILE_O_READ UINT32_C(0x00000001) +/** Open the file with write access. */ +#define RTFILE_O_WRITE UINT32_C(0x00000002) +/** Open the file with read & write access. */ +#define RTFILE_O_READWRITE UINT32_C(0x00000003) +/** The file access mask. + * @remarks The value 0 is invalid, except for windows special case. */ +#define RTFILE_O_ACCESS_MASK UINT32_C(0x00000003) + +/** Open file in APPEND mode, so all writes to the file handle will + * append data at the end of the file. + * @remarks It is ignored if write access is not requested, that is + * RTFILE_O_WRITE is not set. */ +#define RTFILE_O_APPEND UINT32_C(0x00000004) + /* UINT32_C(0x00000008) is unused atm. */ + +/** Sharing mode: deny none. */ +#define RTFILE_O_DENY_NONE UINT32_C(0x00000080) +/** Sharing mode: deny read. */ +#define RTFILE_O_DENY_READ UINT32_C(0x00000010) +/** Sharing mode: deny write. */ +#define RTFILE_O_DENY_WRITE UINT32_C(0x00000020) +/** Sharing mode: deny read and write. */ +#define RTFILE_O_DENY_READWRITE UINT32_C(0x00000030) +/** Sharing mode: deny all. */ +#define RTFILE_O_DENY_ALL RTFILE_O_DENY_READWRITE +/** Sharing mode: do NOT deny delete (NT). + * @remarks This might not be implemented on all platforms, and will be + * defaulted & ignored on those. + */ +#define RTFILE_O_DENY_NOT_DELETE UINT32_C(0x00000040) +/** Sharing mode mask. */ +#define RTFILE_O_DENY_MASK UINT32_C(0x000000f0) + +/** Action: Open an existing file (the default action). */ +#define RTFILE_O_OPEN UINT32_C(0x00000700) +/** Action: Create a new file or open an existing one. */ +#define RTFILE_O_OPEN_CREATE UINT32_C(0x00000100) +/** Action: Create a new a file. */ +#define RTFILE_O_CREATE UINT32_C(0x00000200) +/** Action: Create a new file or replace an existing one. */ +#define RTFILE_O_CREATE_REPLACE UINT32_C(0x00000300) +/** Action mask. */ +#define RTFILE_O_ACTION_MASK UINT32_C(0x00000700) + +/** Turns off indexing of files on Windows hosts, *CREATE* only. + * @remarks Window only. */ +#define RTFILE_O_NOT_CONTENT_INDEXED UINT32_C(0x00000800) +/** Truncate the file. + * @remarks This will not truncate files opened for read-only. + * @remarks The truncation doesn't have to be atomically, so anyone else opening + * the file may be racing us. The caller is responsible for not causing + * this race. */ +#define RTFILE_O_TRUNCATE UINT32_C(0x00001000) +/** Make the handle inheritable on RTProcessCreate(/exec). */ +#define RTFILE_O_INHERIT UINT32_C(0x00002000) +/** Open file in non-blocking mode - non-portable. + * @remarks This flag may not be supported on all platforms, in which case it's + * considered an invalid parameter. */ +#define RTFILE_O_NON_BLOCK UINT32_C(0x00004000) +/** Write through directly to disk. Workaround to avoid iSCSI + * initiator deadlocks on Windows hosts. + * @remarks This might not be implemented on all platforms, and will be ignored + * on those. */ +#define RTFILE_O_WRITE_THROUGH UINT32_C(0x00008000) + +/** Attribute access: Attributes can be read if the file is being opened with + * read access, and can be written with write access. */ +#define RTFILE_O_ACCESS_ATTR_DEFAULT UINT32_C(0x00000000) +/** Attribute access: Attributes can be read. + * @remarks Windows only. */ +#define RTFILE_O_ACCESS_ATTR_READ UINT32_C(0x00010000) +/** Attribute access: Attributes can be written. + * @remarks Windows only. */ +#define RTFILE_O_ACCESS_ATTR_WRITE UINT32_C(0x00020000) +/** Attribute access: Attributes can be both read & written. + * @remarks Windows only. */ +#define RTFILE_O_ACCESS_ATTR_READWRITE UINT32_C(0x00030000) +/** Attribute access: The file attributes access mask. + * @remarks Windows only. */ +#define RTFILE_O_ACCESS_ATTR_MASK UINT32_C(0x00030000) + +/** Open file for async I/O + * @remarks This flag may not be needed on all platforms, and will be ignored on + * those. */ +#define RTFILE_O_ASYNC_IO UINT32_C(0x00040000) + +/** Disables caching. + * + * Useful when using very big files which might bring the host I/O scheduler to + * its knees during high I/O load. + * + * @remarks This flag might impose restrictions + * on the buffer alignment, start offset and/or transfer size. + * + * On Linux the buffer needs to be aligned to the 512 sector + * boundary. + * + * On Windows the FILE_FLAG_NO_BUFFERING is used (see + * http://msdn.microsoft.com/en-us/library/cc644950(VS.85).aspx ). + * The buffer address, the transfer size and offset needs to be aligned + * to the sector size of the volume. Furthermore FILE_APPEND_DATA is + * disabled. To write beyond the size of file use RTFileSetSize prior + * writing the data to the file. + * + * This flag does not work on Solaris if the target filesystem is ZFS. + * RTFileOpen will return an error with that configuration. When used + * with UFS the same alginment restrictions apply like Linux and + * Windows. + * + * @remarks This might not be implemented on all platforms, and will be ignored + * on those. + */ +#define RTFILE_O_NO_CACHE UINT32_C(0x00080000) + +/** Don't allow symbolic links as part of the path. + * @remarks this flag is currently not implemented and will be ignored. */ +#define RTFILE_O_NO_SYMLINKS UINT32_C(0x20000000) + +/** Unix file mode mask for use when creating files. */ +#define RTFILE_O_CREATE_MODE_MASK UINT32_C(0x1ff00000) +/** The number of bits to shift to get the file mode mask. + * To extract it: (fFlags & RTFILE_O_CREATE_MODE_MASK) >> RTFILE_O_CREATE_MODE_SHIFT. + */ +#define RTFILE_O_CREATE_MODE_SHIFT 20 + + /* UINT32_C(0x40000000) + and UINT32_C(0x80000000) are unused atm. */ + +/** Mask of all valid flags. + * @remark This doesn't validate the access mode properly. + */ +#define RTFILE_O_VALID_MASK UINT32_C(0x3ffffff7) + +/** @} */ + + +#ifdef IN_RING3 +/** + * Force the use of open flags for all files opened after the setting is + * changed. The caller is responsible for not causing races with RTFileOpen(). + * + * @returns iprt status code. + * @param fOpenForAccess Access mode to which the set/mask settings apply. + * @param fSet Open flags to be forced set. + * @param fMask Open flags to be masked out. + */ +RTR3DECL(int) RTFileSetForceFlags(unsigned fOpenForAccess, unsigned fSet, unsigned fMask); +#endif /* IN_RING3 */ + +/** + * Open a file. + * + * @returns iprt status code. + * @param pFile Where to store the handle to the opened file. + * @param pszFilename Path to the file which is to be opened. (UTF-8) + * @param fOpen Open flags, i.e a combination of the RTFILE_O_* defines. + * The ACCESS, ACTION and DENY flags are mandatory! + */ +RTDECL(int) RTFileOpen(PRTFILE pFile, const char *pszFilename, uint64_t fOpen); + +/** + * Open a file given as a format string. + * + * @returns iprt status code. + * @param pFile Where to store the handle to the opened file. + * @param fOpen Open flags, i.e a combination of the RTFILE_O_* defines. + * The ACCESS, ACTION and DENY flags are mandatory! + * @param pszFilenameFmt Format string givin the path to the file which is to + * be opened. (UTF-8) + * @param ... Arguments to the format string. + */ +RTDECL(int) RTFileOpenF(PRTFILE pFile, uint64_t fOpen, const char *pszFilenameFmt, ...) RT_IPRT_FORMAT_ATTR(3, 4); + +/** + * Open a file given as a format string. + * + * @returns iprt status code. + * @param pFile Where to store the handle to the opened file. + * @param fOpen Open flags, i.e a combination of the RTFILE_O_* defines. + * The ACCESS, ACTION and DENY flags are mandatory! + * @param pszFilenameFmt Format string givin the path to the file which is to + * be opened. (UTF-8) + * @param va Arguments to the format string. + */ +RTDECL(int) RTFileOpenV(PRTFILE pFile, uint64_t fOpen, const char *pszFilenameFmt, va_list va) RT_IPRT_FORMAT_ATTR(3, 0); + +/** + * Open the bit bucket (aka /dev/null or nul). + * + * @returns IPRT status code. + * @param phFile Where to store the handle to the opened file. + * @param fAccess The desired access only, i.e. read, write or both. + */ +RTDECL(int) RTFileOpenBitBucket(PRTFILE phFile, uint64_t fAccess); + +/** + * Close a file opened by RTFileOpen(). + * + * @returns iprt status code. + * @param File The file handle to close. + */ +RTDECL(int) RTFileClose(RTFILE File); + +/** + * Creates an IPRT file handle from a native one. + * + * @returns IPRT status code. + * @param pFile Where to store the IPRT file handle. + * @param uNative The native handle. + */ +RTDECL(int) RTFileFromNative(PRTFILE pFile, RTHCINTPTR uNative); + +/** + * Gets the native handle for an IPRT file handle. + * + * @return The native handle. + * @param File The IPRT file handle. + */ +RTDECL(RTHCINTPTR) RTFileToNative(RTFILE File); + +/** + * Delete a file. + * + * @returns iprt status code. + * @param pszFilename Path to the file which is to be deleted. (UTF-8) + * @todo This is a RTPath api! + */ +RTDECL(int) RTFileDelete(const char *pszFilename); + +/** @name Seek flags. + * @{ */ +/** Seek from the start of the file. */ +#define RTFILE_SEEK_BEGIN 0x00 +/** Seek from the current file position. */ +#define RTFILE_SEEK_CURRENT 0x01 +/** Seek from the end of the file. */ +#define RTFILE_SEEK_END 0x02 +/** @internal */ +#define RTFILE_SEEK_FIRST RTFILE_SEEK_BEGIN +/** @internal */ +#define RTFILE_SEEK_LAST RTFILE_SEEK_END +/** @} */ + + +/** + * Changes the read & write position in a file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param offSeek Offset to seek. + * @param uMethod Seek method, i.e. one of the RTFILE_SEEK_* defines. + * @param poffActual Where to store the new file position. + * NULL is allowed. + */ +RTDECL(int) RTFileSeek(RTFILE File, int64_t offSeek, unsigned uMethod, uint64_t *poffActual); + +/** + * Read bytes from a file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pvBuf Where to put the bytes we read. + * @param cbToRead How much to read. + * @param *pcbRead How much we actually read . + * If NULL an error will be returned for a partial read. + */ +RTDECL(int) RTFileRead(RTFILE File, void *pvBuf, size_t cbToRead, size_t *pcbRead); + +/** + * Read bytes from a file at a given offset. + * This function may modify the file position. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param off Where to read. + * @param pvBuf Where to put the bytes we read. + * @param cbToRead How much to read. + * @param *pcbRead How much we actually read . + * If NULL an error will be returned for a partial read. + */ +RTDECL(int) RTFileReadAt(RTFILE File, RTFOFF off, void *pvBuf, size_t cbToRead, size_t *pcbRead); + +/** + * Read bytes from a file at a given offset into a S/G buffer. + * This function may modify the file position. + * + * @returns iprt status code. + * @param hFile Handle to the file. + * @param off Where to read. + * @param pSgBuf Pointer to the S/G buffer to read into. + * @param cbToRead How much to read. + * @param *pcbRead How much we actually read . + * If NULL an error will be returned for a partial read. + */ +RTDECL(int) RTFileSgReadAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToRead, size_t *pcbRead); + +/** + * Write bytes to a file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pvBuf What to write. + * @param cbToWrite How much to write. + * @param *pcbWritten How much we actually wrote. + * If NULL an error will be returned for a partial write. + */ +RTDECL(int) RTFileWrite(RTFILE File, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten); + +/** + * Write bytes to a file at a given offset. + * This function may modify the file position. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param off Where to write. + * @param pvBuf What to write. + * @param cbToWrite How much to write. + * @param *pcbWritten How much we actually wrote. + * If NULL an error will be returned for a partial write. + */ +RTDECL(int) RTFileWriteAt(RTFILE File, RTFOFF off, const void *pvBuf, size_t cbToWrite, size_t *pcbWritten); + +/** + * Write bytes from a S/G buffer to a file at a given offset. + * This function may modify the file position. + * + * @returns iprt status code. + * @param hFile Handle to the file. + * @param off Where to write. + * @param pSgBuf What to write. + * @param cbToWrite How much to write. + * @param *pcbWritten How much we actually wrote. + * If NULL an error will be returned for a partial write. + */ +RTDECL(int) RTFileSgWriteAt(RTFILE hFile, RTFOFF off, PRTSGBUF pSgBuf, size_t cbToWrite, size_t *pcbWritten); + +/** + * Flushes the buffers for the specified file. + * + * @returns iprt status code. + * @param File Handle to the file. + */ +RTDECL(int) RTFileFlush(RTFILE File); + +/** + * Set the size of the file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param cbSize The new file size. + */ +RTDECL(int) RTFileSetSize(RTFILE File, uint64_t cbSize); + +/** + * Query the size of the file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pcbSize Where to store the filesize. + */ +RTDECL(int) RTFileGetSize(RTFILE File, uint64_t *pcbSize); + +/** + * Determine the maximum file size. + * + * @returns The max size of the file. + * -1 on failure, the file position is undefined. + * @param File Handle to the file. + * @see RTFileGetMaxSizeEx. + */ +RTDECL(RTFOFF) RTFileGetMaxSize(RTFILE File); + +/** + * Determine the maximum file size. + * + * @returns IPRT status code. + * @param File Handle to the file. + * @param pcbMax Where to store the max file size. + * @see RTFileGetMaxSize. + */ +RTDECL(int) RTFileGetMaxSizeEx(RTFILE File, PRTFOFF pcbMax); + +/** + * Determine the maximum file size depending on the file system the file is stored on. + * + * @returns The max size of the file. + * -1 on failure. + * @param File Handle to the file. + */ +RTDECL(RTFOFF) RTFileGetMaxSize(RTFILE File); + +/** + * Gets the current file position. + * + * @returns File offset. + * @returns ~0UUL on failure. + * @param File Handle to the file. + */ +RTDECL(uint64_t) RTFileTell(RTFILE File); + +/** + * Checks if the supplied handle is valid. + * + * @returns true if valid. + * @returns false if invalid. + * @param File The file handle + */ +RTDECL(bool) RTFileIsValid(RTFILE File); + +/** + * Copies a file. + * + * @returns IPRT status code + * @retval VERR_ALREADY_EXISTS if the destination file exists. + * + * @param pszSrc The path to the source file. + * @param pszDst The path to the destination file. + * This file will be created. + */ +RTDECL(int) RTFileCopy(const char *pszSrc, const char *pszDst); + +/** + * Copies a file given the handles to both files. + * + * @returns IPRT status code + * + * @param FileSrc The source file. The file position is unaltered. + * @param FileDst The destination file. + * On successful returns the file position is at the end of the file. + * On failures the file position and size is undefined. + */ +RTDECL(int) RTFileCopyByHandles(RTFILE FileSrc, RTFILE FileDst); + +/** Flags for RTFileCopyEx(). + * @{ */ +/** Do not use RTFILE_O_DENY_WRITE on the source file to allow for copying files opened for writing. */ +#define RTFILECOPY_FLAGS_NO_SRC_DENY_WRITE RT_BIT(0) +/** Do not use RTFILE_O_DENY_WRITE on the target file. */ +#define RTFILECOPY_FLAGS_NO_DST_DENY_WRITE RT_BIT(1) +/** Do not use RTFILE_O_DENY_WRITE on either of the two files. */ +#define RTFILECOPY_FLAGS_NO_DENY_WRITE ( RTFILECOPY_FLAGS_NO_SRC_DENY_WRITE | RTFILECOPY_FLAGS_NO_DST_DENY_WRITE ) +/** */ +#define RTFILECOPY_FLAGS_MASK UINT32_C(0x00000003) +/** @} */ + +/** + * Copies a file. + * + * @returns IPRT status code + * @retval VERR_ALREADY_EXISTS if the destination file exists. + * + * @param pszSrc The path to the source file. + * @param pszDst The path to the destination file. + * This file will be created. + * @param fFlags Flags (RTFILECOPY_*). + * @param pfnProgress Pointer to callback function for reporting progress. + * @param pvUser User argument to pass to pfnProgress along with the completion percentage. + */ +RTDECL(int) RTFileCopyEx(const char *pszSrc, const char *pszDst, uint32_t fFlags, PFNRTPROGRESS pfnProgress, void *pvUser); + +/** + * Copies a file given the handles to both files and + * provide progress callbacks. + * + * @returns IPRT status code. + * + * @param FileSrc The source file. The file position is unaltered. + * @param FileDst The destination file. + * On successful returns the file position is at the end of the file. + * On failures the file position and size is undefined. + * @param pfnProgress Pointer to callback function for reporting progress. + * @param pvUser User argument to pass to pfnProgress along with the completion percentage. + */ +RTDECL(int) RTFileCopyByHandlesEx(RTFILE FileSrc, RTFILE FileDst, PFNRTPROGRESS pfnProgress, void *pvUser); + + +/** + * Compares two file given the paths to both files. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS if equal. + * @retval VERR_NOT_EQUAL if not equal. + * + * @param pszFile1 The path to the first file. + * @param pszFile2 The path to the second file. + */ +RTDECL(int) RTFileCompare(const char *pszFile1, const char *pszFile2); + +/** + * Compares two file given the handles to both files. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS if equal. + * @retval VERR_NOT_EQUAL if not equal. + * + * @param hFile1 The first file. Undefined return position. + * @param hFile2 The second file. Undefined return position. + */ +RTDECL(int) RTFileCompareByHandles(RTFILE hFile1, RTFILE hFile2); + +/** Flags for RTFileCompareEx(). + * @{ */ +/** Do not use RTFILE_O_DENY_WRITE on the first file. */ +#define RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE1 RT_BIT(0) +/** Do not use RTFILE_O_DENY_WRITE on the second file. */ +#define RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE2 RT_BIT(1) +/** Do not use RTFILE_O_DENY_WRITE on either of the two files. */ +#define RTFILECOMP_FLAGS_NO_DENY_WRITE ( RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE1 | RTFILECOMP_FLAGS_NO_DENY_WRITE_FILE2 ) +/** */ +#define RTFILECOMP_FLAGS_MASK UINT32_C(0x00000003) +/** @} */ + +/** + * Compares two files, extended version with progress callback. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS if equal. + * @retval VERR_NOT_EQUAL if not equal. + * + * @param pszFile1 The path to the source file. + * @param pszFile2 The path to the destination file. This file will be + * created. + * @param fFlags Flags, any of the RTFILECOMP_FLAGS_ \#defines. + * @param pfnProgress Pointer to callback function for reporting progress. + * @param pvUser User argument to pass to pfnProgress along with the completion percentage. + */ +RTDECL(int) RTFileCompareEx(const char *pszFile1, const char *pszFile2, uint32_t fFlags, PFNRTPROGRESS pfnProgress, void *pvUser); + +/** + * Compares two files given their handles, extended version with progress + * callback. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS if equal. + * @retval VERR_NOT_EQUAL if not equal. + * + * @param hFile1 The first file. Undefined return position. + * @param hFile2 The second file. Undefined return position. + * + * @param fFlags Flags, any of the RTFILECOMP_FLAGS_ \#defines, flags + * related to opening of the files will be ignored. + * @param pfnProgress Pointer to callback function for reporting progress. + * @param pvUser User argument to pass to pfnProgress along with the completion percentage. + */ +RTDECL(int) RTFileCompareByHandlesEx(RTFILE hFile1, RTFILE hFile2, uint32_t fFlags, PFNRTPROGRESS pfnProgress, void *pvUser); + +/** + * Renames a file. + * + * Identical to RTPathRename except that it will ensure that the source is not a directory. + * + * @returns IPRT status code. + * @returns VERR_ALREADY_EXISTS if the destination file exists. + * + * @param pszSrc The path to the source file. + * @param pszDst The path to the destination file. + * This file will be created. + * @param fRename See RTPathRename. + */ +RTDECL(int) RTFileRename(const char *pszSrc, const char *pszDst, unsigned fRename); + + +/** @name RTFileMove flags (bit masks). + * @{ */ +/** Replace destination file if present. */ +#define RTFILEMOVE_FLAGS_REPLACE 0x1 +/** Don't allow symbolic links as part of the path. + * @remarks this flag is currently not implemented and will be ignored. */ +#define RTFILEMOVE_FLAGS_NO_SYMLINKS 0x2 +/** @} */ + +/** + * Converts file opening modes (used by fopen, for example) to IPRT + * compatible flags, which then can be used with RTFileOpen* APIs. + * + * @note Handling sharing modes is not supported yet, so RTFILE_O_DENY_NONE + * will always be used. + * + * @return IPRT status code. + * @param pszMode Mode string to convert. + * @param pfMode Where to store the converted mode flags on + * success. + */ +RTDECL(int) RTFileModeToFlags(const char *pszMode, uint64_t *pfMode); + +/** + * Converts file opening modes along with a separate disposition command + * to IPRT compatible flags, which then can be used with RTFileOpen* APIs. + * + * Access modes: + * - "r": Opens a file for reading. + * - "r+": Opens a file for reading and writing. + * - "w": Opens a file for writing. + * - "w+": Opens a file for writing and reading. + * + * Disposition modes: + * - "oe", "open": Opens an existing file or fail if it does not exist. + * - "oc", "open-create": Opens an existing file or create it if it does + * not exist. + * - "oa", "open-append": Opens an existing file and places the file + * pointer at the end of the file, if opened with write access. Create + * the file if it does not exist. + * - "ot", "open-truncate": Opens and truncate an existing file or fail if + * it does not exist. + * - "ce", "create": Creates a new file if it does not exist. Fail if + * exist. + * - "ca", "create-replace": Creates a new file, always. Overwrites an + * existing file. + * + * Sharing mode: + * - "nr": Deny read. + * - "nw": Deny write. + * - "nrw": Deny both read and write. + * - "d": Allow delete. + * - "", NULL: Deny none, except delete. + * + * @return IPRT status code. + * @param pszAccess Access mode string to convert. + * @param pszDisposition Disposition mode string to convert. + * @param pszSharing Sharing mode string to convert. + * @param pfMode Where to store the converted mode flags on success. + */ +RTDECL(int) RTFileModeToFlagsEx(const char *pszAccess, const char *pszDisposition, const char *pszSharing, uint64_t *pfMode); + +/** + * Moves a file. + * + * RTFileMove differs from RTFileRename in that it works across volumes. + * + * @returns IPRT status code. + * @returns VERR_ALREADY_EXISTS if the destination file exists. + * + * @param pszSrc The path to the source file. + * @param pszDst The path to the destination file. + * This file will be created. + * @param fMove A combination of the RTFILEMOVE_* flags. + */ +RTDECL(int) RTFileMove(const char *pszSrc, const char *pszDst, unsigned fMove); + + +/** + * Creates a new file with a unique name using the given template. + * + * One or more trailing X'es in the template will be replaced by random alpha + * numeric characters until a RTFileOpen with RTFILE_O_CREATE succeeds or we + * run out of patience. + * For instance: + * "/tmp/myprog-XXXXXX" + * + * As an alternative to trailing X'es, it is possible to put 3 or more X'es + * somewhere inside the file name. In the following string only the last + * bunch of X'es will be modified: + * "/tmp/myprog-XXX-XXX.tmp" + * + * @returns iprt status code. + * @param pszTemplate The file name template on input. The actual file + * name on success. Empty string on failure. + * @param fMode The mode to create the file with. Use 0600 unless + * you have reason not to. + */ +RTDECL(int) RTFileCreateTemp(char *pszTemplate, RTFMODE fMode); + +/** + * Secure version of @a RTFileCreateTemp with a fixed mode of 0600. + * + * This function behaves in the same way as @a RTFileCreateTemp with two + * additional points. Firstly the mode is fixed to 0600. Secondly it will + * fail if it is not possible to perform the operation securely. Possible + * reasons include that the file could be removed by another unprivileged + * user before it is used (e.g. if is created in a non-sticky /tmp directory) + * or that the path contains symbolic links which another unprivileged user + * could manipulate; however the exact criteria will be specified on a + * platform-by-platform basis as platform support is added. + * @see RTPathIsSecure for the current list of criteria. + * @returns iprt status code. + * @returns VERR_NOT_SUPPORTED if the interface can not be supported on the + * current platform at this time. + * @returns VERR_INSECURE if the file could not be created securely. + * @param pszTemplate The file name template on input. The actual + * file name on success. Empty string on failure. + */ +RTDECL(int) RTFileCreateTempSecure(char *pszTemplate); + +/** + * Opens a new file with a unique name in the temp directory. + * + * Unlike the other temp file creation APIs, this does not allow you any control + * over the name. Nor do you have to figure out where the temporary directory + * is. + * + * @returns iprt status code. + * @param phFile Where to return the handle to the file. + * @param pszFilename Where to return the name (+path) of the file . + * @param cbFilename The size of the buffer @a pszFilename points to. + * @param fOpen The RTFILE_O_XXX flags to open the file with. + * + * @remarks If actual control over the filename or location is required, we'll + * create an extended edition of this API. + */ +RTDECL(int) RTFileOpenTemp(PRTFILE phFile, char *pszFilename, size_t cbFilename, uint64_t fOpen); + + +/** @page pg_rt_filelock RT File locking API description + * + * File locking general rules: + * + * Region to lock or unlock can be located beyond the end of file, this can be used for + * growing files. + * Read (or Shared) locks can be acquired held by an unlimited number of processes at the + * same time, but a Write (or Exclusive) lock can only be acquired by one process, and + * cannot coexist with a Shared lock. To acquire a Read lock, a process must wait until + * there are no processes holding any Write locks. To acquire a Write lock, a process must + * wait until there are no processes holding either kind of lock. + * By default, RTFileLock and RTFileChangeLock calls returns error immediately if the lock + * can't be acquired due to conflict with other locks, however they can be called in wait mode. + * + * Differences in implementation: + * + * Win32, OS/2: Locking is mandatory, since locks are enforced by the operating system. + * I.e. when file region is locked in Read mode, any write in it will fail; in case of Write + * lock - region can be read and writed only by lock's owner. + * + * Win32: File size change (RTFileSetSize) is not controlled by locking at all (!) in the + * operation system. Also see comments to RTFileChangeLock API call. + * + * Linux/Posix: By default locks in Unixes are advisory. This means that cooperating processes + * may use locks to coordinate access to a file between themselves, but programs are also free + * to ignore locks and access the file in any way they choose to. + * + * Additional reading: + * http://en.wikipedia.org/wiki/File_locking + * http://unixhelp.ed.ac.uk/CGI/man-cgi?fcntl+2 + * http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/fs/lockfileex.asp + */ + +/** @name Lock flags (bit masks). + * @{ */ +/** Read access, can be shared with others. */ +#define RTFILE_LOCK_READ 0x00 +/** Write access, one at a time. */ +#define RTFILE_LOCK_WRITE 0x01 +/** Don't wait for other locks to be released. */ +#define RTFILE_LOCK_IMMEDIATELY 0x00 +/** Wait till conflicting locks have been released. */ +#define RTFILE_LOCK_WAIT 0x02 +/** Valid flags mask */ +#define RTFILE_LOCK_MASK 0x03 +/** @} */ + + +/** + * Locks a region of file for read (shared) or write (exclusive) access. + * + * @returns iprt status code. + * @returns VERR_FILE_LOCK_VIOLATION if lock can't be acquired. + * @param File Handle to the file. + * @param fLock Lock method and flags, see RTFILE_LOCK_* defines. + * @param offLock Offset of lock start. + * @param cbLock Length of region to lock, may overlap the end of file. + */ +RTDECL(int) RTFileLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock); + +/** + * Changes a lock type from read to write or from write to read. + * The region to type change must correspond exactly to an existing locked region. + * If change can't be done due to locking conflict and non-blocking mode is used, error is + * returned and lock keeps its state (see next warning). + * + * WARNING: win32 implementation of this call is not atomic, it transforms to a pair of + * calls RTFileUnlock and RTFileLock. Potentially the previously acquired lock can be + * lost, i.e. function is called in non-blocking mode, previous lock is freed, new lock can't + * be acquired, and old lock (previous state) can't be acquired back too. This situation + * may occurs _only_ if the other process is acquiring a _write_ lock in blocking mode or + * in race condition with the current call. + * In this very bad case special error code VERR_FILE_LOCK_LOST will be returned. + * + * @returns iprt status code. + * @returns VERR_FILE_NOT_LOCKED if region was not locked. + * @returns VERR_FILE_LOCK_VIOLATION if lock type can't be changed, lock remains its type. + * @returns VERR_FILE_LOCK_LOST if lock was lost, we haven't this lock anymore :( + * @param File Handle to the file. + * @param fLock Lock method and flags, see RTFILE_LOCK_* defines. + * @param offLock Offset of lock start. + * @param cbLock Length of region to lock, may overlap the end of file. + */ +RTDECL(int) RTFileChangeLock(RTFILE File, unsigned fLock, int64_t offLock, uint64_t cbLock); + +/** + * Unlocks previously locked region of file. + * The region to unlock must correspond exactly to an existing locked region. + * + * @returns iprt status code. + * @returns VERR_FILE_NOT_LOCKED if region was not locked. + * @param File Handle to the file. + * @param offLock Offset of lock start. + * @param cbLock Length of region to unlock, may overlap the end of file. + */ +RTDECL(int) RTFileUnlock(RTFILE File, int64_t offLock, uint64_t cbLock); + + +/** + * Query information about an open file. + * + * @returns iprt status code. + * + * @param File Handle to the file. + * @param pObjInfo Object information structure to be filled on successful return. + * @param enmAdditionalAttribs Which set of additional attributes to request. + * Use RTFSOBJATTRADD_NOTHING if this doesn't matter. + */ +RTDECL(int) RTFileQueryInfo(RTFILE File, PRTFSOBJINFO pObjInfo, RTFSOBJATTRADD enmAdditionalAttribs); + +/** + * Changes one or more of the timestamps associated of file system object. + * + * @returns iprt status code. + * @retval VERR_NOT_SUPPORTED is returned if the operation isn't supported by + * the OS. + * + * @param File Handle to the file. + * @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. + * + * @remark The file system might not implement all these time attributes, + * the API will ignore the ones which aren't supported. + * + * @remark The file system might not implement the time resolution + * employed by this interface, the time will be chopped to fit. + * + * @remark The file system may update the change time even if it's + * not specified. + * + * @remark POSIX can only set Access & Modification and will always set both. + */ +RTDECL(int) RTFileSetTimes(RTFILE File, PCRTTIMESPEC pAccessTime, PCRTTIMESPEC pModificationTime, + PCRTTIMESPEC pChangeTime, PCRTTIMESPEC pBirthTime); + +/** + * Gets one or more of the timestamps associated of file system object. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pAccessTime Where to store the access time. NULL is ok. + * @param pModificationTime Where to store the modifcation time. NULL is ok. + * @param pChangeTime Where to store the change time. NULL is ok. + * @param pBirthTime Where to store the time of birth. NULL is ok. + * + * @remark This is wrapper around RTFileQueryInfo() and exists to complement RTFileSetTimes(). + */ +RTDECL(int) RTFileGetTimes(RTFILE File, PRTTIMESPEC pAccessTime, PRTTIMESPEC pModificationTime, + PRTTIMESPEC pChangeTime, PRTTIMESPEC pBirthTime); + +/** + * Changes the mode flags of an open file. + * + * The API requires at least one of the mode flag sets (Unix/Dos) to + * be set. The type is ignored. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param fMode The new file mode, see @ref grp_rt_fs for details. + */ +RTDECL(int) RTFileSetMode(RTFILE File, RTFMODE fMode); + +/** + * Gets the mode flags of an open file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pfMode Where to store the file mode, see @ref grp_rt_fs for details. + * + * @remark This is wrapper around RTFileQueryInfo() + * and exists to complement RTFileSetMode(). + */ +RTDECL(int) RTFileGetMode(RTFILE File, uint32_t *pfMode); + +/** + * Changes the owner and/or group of an open file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param uid The new file owner user id. Pass NIL_RTUID to leave + * this unchanged. + * @param gid The new group id. Pass NIL_RTGID to leave this + * unchanged. + */ +RTDECL(int) RTFileSetOwner(RTFILE File, uint32_t uid, uint32_t gid); + +/** + * Gets the owner and/or group of an open file. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param pUid Where to store the owner user id. NULL is ok. + * @param pGid Where to store the group id. NULL is ok. + * + * @remark This is wrapper around RTFileQueryInfo() and exists to complement RTFileGetOwner(). + */ +RTDECL(int) RTFileGetOwner(RTFILE File, uint32_t *pUid, uint32_t *pGid); + +/** + * Executes an IOCTL on a file descriptor. + * + * This function is currently only available in L4 and posix environments. + * Attemps at calling it from code shared with any other platforms will break things! + * + * The rational for defining this API is to simplify L4 porting of audio drivers, + * and to remove some of the assumptions on RTFILE being a file descriptor on + * platforms using the posix file implementation. + * + * @returns iprt status code. + * @param File Handle to the file. + * @param ulRequest IOCTL request to carry out. + * @param pvData IOCTL data. + * @param cbData Size of the IOCTL data. + * @param piRet Return value of the IOCTL request. + */ +RTDECL(int) RTFileIoCtl(RTFILE File, unsigned long ulRequest, void *pvData, unsigned cbData, int *piRet); + +/** + * Query the sizes of a filesystem. + * + * @returns iprt status code. + * @retval VERR_NOT_SUPPORTED is returned if the operation isn't supported by + * the OS. + * + * @param hFile The file handle. + * @param pcbTotal Where to store the total filesystem space. (Optional) + * @param pcbFree Where to store the remaining free space in the filesystem. (Optional) + * @param pcbBlock Where to store the block size. (Optional) + * @param pcbSector Where to store the sector size. (Optional) + * + * @sa RTFsQuerySizes + */ +RTDECL(int) RTFileQueryFsSizes(RTFILE hFile, PRTFOFF pcbTotal, RTFOFF *pcbFree, + uint32_t *pcbBlock, uint32_t *pcbSector); + +/** + * Reads the file into memory. + * + * The caller must free the memory using RTFileReadAllFree(). + * + * @returns IPRT status code. + * @param pszFilename The name of the file. + * @param ppvFile Where to store the pointer to the memory on successful return. + * @param pcbFile Where to store the size of the returned memory. + * + * @remarks Note that this function may be implemented using memory mapping, which means + * that the file may remain open until RTFileReadAllFree() is called. It also + * means that the return memory may reflect the state of the file when it's + * accessed instead of when this call was done. So, in short, don't use this + * API for volatile files, then rather use the extended variant with a + * yet-to-be-defined flag. + */ +RTDECL(int) RTFileReadAll(const char *pszFilename, void **ppvFile, size_t *pcbFile); + +/** + * Reads the file into memory. + * + * The caller must free the memory using RTFileReadAllFree(). + * + * @returns IPRT status code. + * @param pszFilename The name of the file. + * @param off The offset to start reading at. + * @param cbMax The maximum number of bytes to read into memory. Specify RTFOFF_MAX + * to read to the end of the file. + * @param fFlags See RTFILE_RDALL_*. + * @param ppvFile Where to store the pointer to the memory on successful return. + * @param pcbFile Where to store the size of the returned memory. + * + * @remarks See the remarks for RTFileReadAll. + */ +RTDECL(int) RTFileReadAllEx(const char *pszFilename, RTFOFF off, RTFOFF cbMax, uint32_t fFlags, void **ppvFile, size_t *pcbFile); + +/** + * Reads the file into memory. + * + * The caller must free the memory using RTFileReadAllFree(). + * + * @returns IPRT status code. + * @param File The handle to the file. + * @param ppvFile Where to store the pointer to the memory on successful return. + * @param pcbFile Where to store the size of the returned memory. + * + * @remarks See the remarks for RTFileReadAll. + */ +RTDECL(int) RTFileReadAllByHandle(RTFILE File, void **ppvFile, size_t *pcbFile); + +/** + * Reads the file into memory. + * + * The caller must free the memory using RTFileReadAllFree(). + * + * @returns IPRT status code. + * @param File The handle to the file. + * @param off The offset to start reading at. + * @param cbMax The maximum number of bytes to read into memory. Specify RTFOFF_MAX + * to read to the end of the file. + * @param fFlags See RTFILE_RDALL_*. + * @param ppvFile Where to store the pointer to the memory on successful return. + * @param pcbFile Where to store the size of the returned memory. + * + * @remarks See the remarks for RTFileReadAll. + */ +RTDECL(int) RTFileReadAllByHandleEx(RTFILE File, RTFOFF off, RTFOFF cbMax, uint32_t fFlags, void **ppvFile, size_t *pcbFile); + +/** + * Frees the memory returned by one of the RTFileReadAll(), RTFileReadAllEx(), + * RTFileReadAllByHandle() and RTFileReadAllByHandleEx() functions. + * + * @param pvFile Pointer to the memory. + * @param cbFile The size of the memory. + */ +RTDECL(void) RTFileReadAllFree(void *pvFile, size_t cbFile); + +/** @name RTFileReadAllEx and RTFileReadAllHandleEx flags + * The open flags are ignored by RTFileReadAllHandleEx. + * @{ */ +#define RTFILE_RDALL_O_DENY_NONE RTFILE_O_DENY_NONE +#define RTFILE_RDALL_O_DENY_READ RTFILE_O_DENY_READ +#define RTFILE_RDALL_O_DENY_WRITE RTFILE_O_DENY_WRITE +#define RTFILE_RDALL_O_DENY_READWRITE RTFILE_O_DENY_READWRITE +#define RTFILE_RDALL_O_DENY_ALL RTFILE_O_DENY_ALL +#define RTFILE_RDALL_O_DENY_NOT_DELETE RTFILE_O_DENY_NOT_DELETE +#define RTFILE_RDALL_O_DENY_MASK RTFILE_O_DENY_MASK +/** Fail with VERR_OUT_OF_RANGE if the file size exceeds the specified maximum + * size. The default behavior is to cap the size at cbMax. */ +#define RTFILE_RDALL_F_FAIL_ON_MAX_SIZE RT_BIT_32(30) +/** Add a trailing zero byte to facilitate reading text files. */ +#define RTFILE_RDALL_F_TRAILING_ZERO_BYTE RT_BIT_32(31) +/** Mask of valid flags. */ +#define RTFILE_RDALL_VALID_MASK (RTFILE_RDALL_O_DENY_MASK | UINT32_C(0xc0000000)) +/** @} */ + +/** + * Sets the current size of the file ensuring that all required blocks + * are allocated on the underlying medium. + * + * @returns IPRT status code. + * @retval VERR_NOT_SUPPORTED if either this operation is not supported on the + * current host in an efficient manner or the given combination of + * flags is not supported. + * @param hFile The handle to the file. + * @param cbSize The new size of the file to allocate. + * @param fFlags Combination of RTFILE_ALLOC_SIZE_F_* + */ +RTDECL(int) RTFileSetAllocationSize(RTFILE hFile, uint64_t cbSize, uint32_t fFlags); + +/** @name RTFILE_ALLOC_SIZE_F_XXX - RTFileSetAllocationSize flags + * @{ */ +/** Default flags. */ +#define RTFILE_ALLOC_SIZE_F_DEFAULT 0 +/** Do not change the size of the file if the given size is bigger than the + * current file size. + * + * Useful to preallocate blocks beyond the current size for appending data in an + * efficient manner. Might not be supported on all hosts and will return + * VERR_NOT_SUPPORTED in that case. */ +#define RTFILE_ALLOC_SIZE_F_KEEP_SIZE RT_BIT(0) +/** Mask of valid flags. */ +#define RTFILE_ALLOC_SIZE_F_VALID (RTFILE_ALLOC_SIZE_F_KEEP_SIZE) +/** @} */ + + +#ifdef IN_RING3 + +/** @page pg_rt_asyncio RT File async I/O API + * + * File operations are usually blocking the calling thread until + * they completed making it impossible to let the thread do anything + * else in-between. + * The RT File async I/O API provides an easy and efficient way to + * access files asynchronously using the native facilities provided + * by each operating system. + * + * @section sec_rt_asyncio_objects Objects + * + * There are two objects used in this API. + * The first object is the request. A request contains every information + * needed two complete the file operation successfully like the start offset + * and pointer to the source or destination buffer. + * Requests are created with RTFileAioReqCreate() and destroyed with + * RTFileAioReqDestroy(). + * Because creating a request may require allocating various operating + * system dependent resources and may be quite expensive it is possible + * to use a request more than once to save CPU cycles. + * A request is constructed with either RTFileAioReqPrepareRead() + * which will set up a request to read from the given file or + * RTFileAioReqPrepareWrite() which will write to a given file. + * + * The second object is the context. A file is associated with a context + * and requests for this file may complete only on the context the file + * was associated with and not on the context given in RTFileAioCtxSubmit() + * (see below for further information). + * RTFileAioCtxWait() is used to wait for completion of requests which were + * associated with the context. While waiting for requests the thread can not + * respond to global state changes. That's why the API provides a way to let + * RTFileAioCtxWait() return immediately no matter how many requests + * have finished through RTFileAioCtxWakeup(). The return code is + * VERR_INTERRUPTED to let the thread know that he got interrupted. + * + * @section sec_rt_asyncio_request_states Request states + * + * Created: + * After a request was created with RTFileAioReqCreate() it is in the same state + * like it just completed successfully. RTFileAioReqGetRC() will return VINF_SUCCESS + * and a transfer size of 0. RTFileAioReqGetUser() will return NULL. The request can be + * destroyed RTFileAioReqDestroy(). It is also allowed to prepare a the request + * for a data transfer with the RTFileAioReqPrepare* methods. + * Calling any other method like RTFileAioCtxSubmit() will return VERR_FILE_AIO_NOT_PREPARED + * and RTFileAioReqCancel() returns VERR_FILE_AIO_NOT_SUBMITTED. + * + * Prepared: + * A request will enter this state if one of the RTFileAioReqPrepare* methods + * is called. In this state you can still destroy and retrieve the user data + * associated with the request but trying to cancel the request or getting + * the result of the operation will return VERR_FILE_AIO_NOT_SUBMITTED. + * + * Submitted: + * A prepared request can be submitted with RTFileAioCtxSubmit(). If the operation + * succeeds it is not allowed to touch the request or free any resources until + * it completed through RTFileAioCtxWait(). The only allowed method is RTFileAioReqCancel() + * which tries to cancel the request. The request will go into the completed state + * and RTFileAioReqGetRC() will return VERR_FILE_AIO_CANCELED. + * If the request completes not matter if successfully or with an error it will + * switch into the completed state. RTFileReqDestroy() fails if the given request + * is in this state. + * + * Completed: + * The request will be in this state after it completed and returned through + * RTFileAioCtxWait(). RTFileAioReqGetRC() returns the final result code + * and the number of bytes transferred. + * The request can be used for new data transfers. + * + * @section sec_rt_asyncio_threading Threading + * + * The API is a thin wrapper around the specific host OS APIs and therefore + * relies on the thread safety of the underlying API. + * The interesting functions with regards to thread safety are RTFileAioCtxSubmit() + * and RTFileAioCtxWait(). RTFileAioCtxWait() must not be called from different + * threads at the same time with the same context handle. The same applies to + * RTFileAioCtxSubmit(). However it is possible to submit new requests from a different + * thread while waiting for completed requests on another thread with RTFileAioCtxWait(). + * + * @section sec_rt_asyncio_implementations Differences in implementation + * + * Because the host APIs are quite different on every OS and every API has other limitations + * there are some things to consider to make the code as portable as possible. + * + * The first restriction at the moment is that every buffer has to be aligned to a 512 byte boundary. + * This limitation comes from the Linux io_* interface. To use the interface the file + * must be opened with O_DIRECT. This flag disables the kernel cache too which may + * degrade performance but is unfortunately the only way to make asynchronous + * I/O work till today (if O_DIRECT is omitted io_submit will revert to sychronous behavior + * and will return when the requests finished and when they are queued). + * It is mostly used by DBMS which do theire own caching. + * Furthermore there is no filesystem independent way to discover the restrictions at least + * for the 2.4 kernel series. Since 2.6 the 512 byte boundary seems to be used by all + * file systems. So Linus comment about this flag is comprehensible but Linux + * lacks an alternative at the moment. + * + * The next limitation applies only to Windows. Requests are not associated with the + * I/O context they are associated with but with the file the request is for. + * The file needs to be associated with exactly one I/O completion port and requests + * for this file will only arrive at that context after they completed and not on + * the context the request was submitted. + * To associate a file with a specific context RTFileAioCtxAssociateWithFile() is + * used. It is only implemented on Windows and does nothing on the other platforms. + * If the file needs to be associated with different context for some reason + * the file must be closed first. After it was opened again the new context + * can be associated with the other context. + * This can't be done by the API because there is no way to retrieve the flags + * the file was opened with. + */ + +/** + * Global limits for the AIO API. + */ +typedef struct RTFILEAIOLIMITS +{ + /** Global number of simultaneous outstanding requests allowed. + * RTFILEAIO_UNLIMITED_REQS means no limit. */ + uint32_t cReqsOutstandingMax; + /** The alignment data buffers need to have. + * 0 means no alignment restrictions. */ + uint32_t cbBufferAlignment; +} RTFILEAIOLIMITS; +/** A pointer to a AIO limits structure. */ +typedef RTFILEAIOLIMITS *PRTFILEAIOLIMITS; + +/** + * Returns the global limits for the AIO API. + * + * @returns IPRT status code. + * @retval VERR_NOT_SUPPORTED if the host does not support the async I/O API. + * + * @param pAioLimits Where to store the global limit information. + */ +RTDECL(int) RTFileAioGetLimits(PRTFILEAIOLIMITS pAioLimits); + +/** + * Creates an async I/O request handle. + * + * @returns IPRT status code. + * @param phReq Where to store the request handle. + */ +RTDECL(int) RTFileAioReqCreate(PRTFILEAIOREQ phReq); + +/** + * Destroys an async I/O request handle. + * + * @returns IPRT status code. + * @retval VERR_FILE_AIO_IN_PROGRESS if the request is still in progress. + * + * @param hReq The request handle. + */ +RTDECL(int) RTFileAioReqDestroy(RTFILEAIOREQ hReq); + +/** + * Prepares an async read request. + * + * @returns IPRT status code. + * @retval VERR_FILE_AIO_IN_PROGRESS if the request is still in progress. + * + * @param hReq The request handle. + * @param hFile The file to read from. + * @param off The offset to start reading at. + * @param pvBuf Where to store the read bits. + * @param cbRead Number of bytes to read. + * @param pvUser Opaque user data associated with this request which + * can be retrieved with RTFileAioReqGetUser(). + */ +RTDECL(int) RTFileAioReqPrepareRead(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off, + void *pvBuf, size_t cbRead, void *pvUser); + +/** + * Prepares an async write request. + * + * @returns IPRT status code. + * @retval VERR_FILE_AIO_IN_PROGRESS if the request is still in progress. + * + * @param hReq The request handle. + * @param hFile The file to write to. + * @param off The offset to start writing at. + * @param pvBuf The bits to write. + * @param cbWrite Number of bytes to write. + * @param pvUser Opaque user data associated with this request which + * can be retrieved with RTFileAioReqGetUser(). + */ +RTDECL(int) RTFileAioReqPrepareWrite(RTFILEAIOREQ hReq, RTFILE hFile, RTFOFF off, + void const *pvBuf, size_t cbWrite, void *pvUser); + +/** + * Prepares an async flush of all cached data associated with a file handle. + * + * @returns IPRT status code. + * @retval VERR_FILE_AIO_IN_PROGRESS if the request is still in progress. + * + * @param hReq The request handle. + * @param hFile The file to flush. + * @param pvUser Opaque user data associated with this request which + * can be retrieved with RTFileAioReqGetUser(). + * + * @remarks May also flush other caches on some platforms. + */ +RTDECL(int) RTFileAioReqPrepareFlush(RTFILEAIOREQ hReq, RTFILE hFile, void *pvUser); + +/** + * Gets the opaque user data associated with the given request. + * + * @returns Opaque user data. + * @retval NULL if the request hasn't been prepared yet. + * + * @param hReq The request handle. + */ +RTDECL(void *) RTFileAioReqGetUser(RTFILEAIOREQ hReq); + +/** + * Cancels a pending request. + * + * @returns IPRT status code. + * @retval VINF_SUCCESS If the request was canceled. + * @retval VERR_FILE_AIO_NOT_SUBMITTED If the request wasn't submitted yet. + * @retval VERR_FILE_AIO_IN_PROGRESS If the request could not be canceled because it is already processed. + * @retval VERR_FILE_AIO_COMPLETED If the request could not be canceled because it already completed. + * + * @param hReq The request to cancel. + */ +RTDECL(int) RTFileAioReqCancel(RTFILEAIOREQ hReq); + +/** + * Gets the status of a completed request. + * + * @returns The IPRT status code of the given request. + * @retval VERR_FILE_AIO_NOT_SUBMITTED if the request wasn't submitted yet. + * @retval VERR_FILE_AIO_CANCELED if the request was canceled. + * @retval VERR_FILE_AIO_IN_PROGRESS if the request isn't yet completed. + * + * @param hReq The request handle. + * @param pcbTransferred Where to store the number of bytes transferred. + * Optional since it is not relevant for all kinds of + * requests. + */ +RTDECL(int) RTFileAioReqGetRC(RTFILEAIOREQ hReq, size_t *pcbTransferred); + + + +/** + * Creates an async I/O context. + * + * @todo briefly explain what an async context is here or in the page + * above. + * + * @returns IPRT status code. + * @param phAioCtx Where to store the async I/O context handle. + * @param cAioReqsMax How many async I/O requests the context should be capable + * to handle. Pass RTFILEAIO_UNLIMITED_REQS if the + * context should support an unlimited number of + * requests. + * @param fFlags Combination of RTFILEAIOCTX_FLAGS_*. + */ +RTDECL(int) RTFileAioCtxCreate(PRTFILEAIOCTX phAioCtx, uint32_t cAioReqsMax, + uint32_t fFlags); + +/** Unlimited number of requests. + * Used with RTFileAioCtxCreate and RTFileAioCtxGetMaxReqCount. */ +#define RTFILEAIO_UNLIMITED_REQS UINT32_MAX + +/** When set RTFileAioCtxWait() will always wait for completing requests, + * even when there is none waiting currently, instead of returning + * VERR_FILE_AIO_NO_REQUEST. */ +#define RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS RT_BIT_32(0) +/** mask of valid flags. */ +#define RTFILEAIOCTX_FLAGS_VALID_MASK (RTFILEAIOCTX_FLAGS_WAIT_WITHOUT_PENDING_REQUESTS) + +/** + * Destroys an async I/O context. + * + * @returns IPRT status code. + * @param hAioCtx The async I/O context handle. + */ +RTDECL(int) RTFileAioCtxDestroy(RTFILEAIOCTX hAioCtx); + +/** + * Get the maximum number of requests one aio context can handle. + * + * @returns Maximum number of tasks the context can handle. + * RTFILEAIO_UNLIMITED_REQS if there is no limit. + * + * @param hAioCtx The async I/O context handle. + * If NIL_RTAIOCONTEXT is passed the maximum value + * which can be passed to RTFileAioCtxCreate() + * is returned. + */ +RTDECL(uint32_t) RTFileAioCtxGetMaxReqCount(RTFILEAIOCTX hAioCtx); + +/** + * Associates a file with an async I/O context. + * Requests for this file will arrive at the completion port + * associated with the file. + * + * @returns IPRT status code. + * + * @param hAioCtx The async I/O context handle. + * @param hFile The file handle. + */ +RTDECL(int) RTFileAioCtxAssociateWithFile(RTFILEAIOCTX hAioCtx, RTFILE hFile); + +/** + * Submits a set of requests to an async I/O context for processing. + * + * @returns IPRT status code. + * @returns VERR_FILE_AIO_INSUFFICIENT_RESSOURCES if the maximum number of + * simultaneous outstanding requests would be exceeded. + * + * @param hAioCtx The async I/O context handle. + * @param pahReqs Pointer to an array of request handles. + * @param cReqs The number of entries in the array. + * + * @remarks It is possible that some requests could be submitted successfully + * even if the method returns an error code. In that case RTFileAioReqGetRC() + * can be used to determine the status of a request. + * If it returns VERR_FILE_AIO_IN_PROGRESS it was submitted successfully. + * Any other error code may indicate why the request failed. + * VERR_FILE_AIO_NOT_SUBMITTED indicates that a request wasn't submitted + * probably because the previous request encountered an error. + * + * @remarks @a cReqs uses the type size_t while it really is a uint32_t, this is + * to avoid annoying warnings when using RT_ELEMENTS and similar + * macros. + */ +RTDECL(int) RTFileAioCtxSubmit(RTFILEAIOCTX hAioCtx, PRTFILEAIOREQ pahReqs, size_t cReqs); + +/** + * Waits for request completion. + * + * Only one thread at a time may call this API on a context. + * + * @returns IPRT status code. + * @retval VERR_INVALID_POINTER If pcReqs or/and pahReqs are invalid. + * @retval VERR_INVALID_HANDLE If hAioCtx is invalid. + * @retval VERR_OUT_OF_RANGE If cMinReqs is larger than cReqs. + * @retval VERR_INVALID_PARAMETER If cReqs is 0. + * @retval VERR_TIMEOUT If cMinReqs didn't complete before the + * timeout expired. + * @retval VERR_INTERRUPTED If the completion context was interrupted + * by RTFileAioCtxWakeup(). + * @retval VERR_FILE_AIO_NO_REQUEST If there are no pending request. + * + * @param hAioCtx The async I/O context handle to wait and get + * completed requests from. + * @param cMinReqs The minimum number of requests which have to + * complete before this function returns. + * @param cMillies The number of milliseconds to wait before returning + * VERR_TIMEOUT. Use RT_INDEFINITE_WAIT to wait + * forever. + * @param pahReqs Pointer to an array where the handles of the + * completed requests will be stored on success. + * @param cReqs The number of entries @a pahReqs can hold. + * @param pcReqs Where to store the number of returned (complete) + * requests. This will always be set. + * + * @remarks The wait will be resume if interrupted by a signal. An + * RTFileAioCtxWaitNoResume variant can be added later if it becomes + * necessary. + * + * @remarks @a cMinReqs and @a cReqs use the type size_t while they really are + * uint32_t's, this is to avoid annoying warnings when using + * RT_ELEMENTS and similar macros. + */ +RTDECL(int) RTFileAioCtxWait(RTFILEAIOCTX hAioCtx, size_t cMinReqs, RTMSINTERVAL cMillies, + PRTFILEAIOREQ pahReqs, size_t cReqs, uint32_t *pcReqs); + +/** + * Forces any RTFileAioCtxWait() call on another thread to return immediately. + * + * @returns IPRT status code. + * + * @param hAioCtx The handle of the async I/O context to wakeup. + */ +RTDECL(int) RTFileAioCtxWakeup(RTFILEAIOCTX hAioCtx); + +#endif /* IN_RING3 */ + +/** @} */ + +RT_C_DECLS_END + +#endif /* !IPRT_INCLUDED_file_h */ + |