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/*-------------------------------------------------------------------------
*
* fd.h
* Virtual file descriptor definitions.
*
*
* Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/storage/fd.h
*
*-------------------------------------------------------------------------
*/
/*
* calls:
*
* File {Close, Read, Write, Seek, Tell, Sync}
* {Path Name Open, Allocate, Free} File
*
* These are NOT JUST RENAMINGS OF THE UNIX ROUTINES.
* Use them for all file activity...
*
* File fd;
* fd = PathNameOpenFile("foo", O_RDONLY, 0600);
*
* AllocateFile();
* FreeFile();
*
* Use AllocateFile, not fopen, if you need a stdio file (FILE*); then
* use FreeFile, not fclose, to close it. AVOID using stdio for files
* that you intend to hold open for any length of time, since there is
* no way for them to share kernel file descriptors with other files.
*
* Likewise, use AllocateDir/FreeDir, not opendir/closedir, to allocate
* open directories (DIR*), and OpenTransientFile/CloseTransient File for an
* unbuffered file descriptor.
*/
#ifndef FD_H
#define FD_H
#include <dirent.h>
/*
* FileSeek uses the standard UNIX lseek(2) flags.
*/
typedef char *FileName;
typedef int File;
/* GUC parameter */
extern PGDLLIMPORT int max_files_per_process;
/*
* This is private to fd.c, but exported for save/restore_backend_variables()
*/
extern int max_safe_fds;
/*
* prototypes for functions in fd.c
*/
/* Operations on virtual Files --- equivalent to Unix kernel file ops */
extern File PathNameOpenFile(FileName fileName, int fileFlags, int fileMode);
extern File OpenTemporaryFile(bool interXact);
extern void FileClose(File file);
extern int FilePrefetch(File file, off_t offset, int amount);
extern int FileRead(File file, char *buffer, int amount);
extern int FileWrite(File file, char *buffer, int amount);
extern int FileSync(File file);
extern off_t FileSeek(File file, off_t offset, int whence);
extern int FileTruncate(File file, off_t offset);
extern void FileWriteback(File file, off_t offset, off_t nbytes);
extern char *FilePathName(File file);
extern int FileGetRawDesc(File file);
extern int FileGetRawFlags(File file);
extern int FileGetRawMode(File file);
/* Operations that allow use of regular stdio --- USE WITH CAUTION */
extern FILE *AllocateFile(const char *name, const char *mode);
extern int FreeFile(FILE *file);
/* Operations that allow use of pipe streams (popen/pclose) */
extern FILE *OpenPipeStream(const char *command, const char *mode);
extern int ClosePipeStream(FILE *file);
/* Operations to allow use of the <dirent.h> library routines */
extern DIR *AllocateDir(const char *dirname);
extern struct dirent *ReadDir(DIR *dir, const char *dirname);
extern struct dirent *ReadDirExtended(DIR *dir, const char *dirname,
int elevel);
extern int FreeDir(DIR *dir);
/* Operations to allow use of a plain kernel FD, with automatic cleanup */
extern int OpenTransientFile(FileName fileName, int fileFlags, int fileMode);
extern int CloseTransientFile(int fd);
/* If you've really really gotta have a plain kernel FD, use this */
extern int BasicOpenFile(FileName fileName, int fileFlags, int fileMode);
/* Miscellaneous support routines */
extern void InitFileAccess(void);
extern void set_max_safe_fds(void);
extern void closeAllVfds(void);
extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces);
extern bool TempTablespacesAreSet(void);
extern Oid GetNextTempTableSpace(void);
extern void AtEOXact_Files(void);
extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
SubTransactionId parentSubid);
extern void RemovePgTempFiles(void);
extern int pg_fsync(int fd);
extern int pg_fsync_no_writethrough(int fd);
extern int pg_fsync_writethrough(int fd);
extern int pg_fdatasync(int fd);
extern void pg_flush_data(int fd, off_t offset, off_t amount);
extern void fsync_fname(const char *fname, bool isdir);
extern int durable_rename(const char *oldfile, const char *newfile, int loglevel);
extern int durable_link_or_rename(const char *oldfile, const char *newfile, int loglevel);
extern void SyncDataDirectory(void);
/* Filename components for OpenTemporaryFile */
#define PG_TEMP_FILES_DIR "pgsql_tmp"
#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
#endif /* FD_H */
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