159 lines
6.0 KiB
C
159 lines
6.0 KiB
C
/*-------------------------------------------------------------------------
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*
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* fd.h
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* Virtual file descriptor definitions.
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*
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*
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* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/storage/fd.h
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* calls:
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*
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* File {Close, Read, Write, Size, Sync}
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* {Path Name Open, Allocate, Free} File
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*
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* These are NOT JUST RENAMINGS OF THE UNIX ROUTINES.
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* Use them for all file activity...
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*
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* File fd;
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* fd = PathNameOpenFile("foo", O_RDONLY);
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*
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* AllocateFile();
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* FreeFile();
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*
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* Use AllocateFile, not fopen, if you need a stdio file (FILE*); then
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* use FreeFile, not fclose, to close it. AVOID using stdio for files
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* that you intend to hold open for any length of time, since there is
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* no way for them to share kernel file descriptors with other files.
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*
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* Likewise, use AllocateDir/FreeDir, not opendir/closedir, to allocate
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* open directories (DIR*), and OpenTransientFile/CloseTransientFile for an
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* unbuffered file descriptor.
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*/
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#ifndef FD_H
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#define FD_H
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#include <dirent.h>
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typedef int File;
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/* GUC parameter */
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extern PGDLLIMPORT int max_files_per_process;
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extern PGDLLIMPORT bool data_sync_retry;
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/*
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* This is private to fd.c, but exported for save/restore_backend_variables()
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*/
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extern int max_safe_fds;
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/*
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* On Windows, we have to interpret EACCES as possibly meaning the same as
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* ENOENT, because if a file is unlinked-but-not-yet-gone on that platform,
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* that's what you get. Ugh. This code is designed so that we don't
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* actually believe these cases are okay without further evidence (namely,
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* a pending fsync request getting canceled ... see ProcessSyncRequests).
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*/
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#ifndef WIN32
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#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT)
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#else
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#define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES)
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#endif
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/*
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* prototypes for functions in fd.c
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*/
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/* Operations on virtual Files --- equivalent to Unix kernel file ops */
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extern File PathNameOpenFile(const char *fileName, int fileFlags);
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extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
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extern File OpenTemporaryFile(bool interXact);
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extern void FileClose(File file);
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extern int FilePrefetch(File file, off_t offset, int amount, uint32 wait_event_info);
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extern int FileRead(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info);
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extern int FileWrite(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info);
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extern int FileSync(File file, uint32 wait_event_info);
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extern off_t FileSize(File file);
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extern int FileTruncate(File file, off_t offset, uint32 wait_event_info);
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extern void FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info);
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extern char *FilePathName(File file);
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extern int FileGetRawDesc(File file);
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extern int FileGetRawFlags(File file);
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extern mode_t FileGetRawMode(File file);
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/* Operations used for sharing named temporary files */
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extern File PathNameCreateTemporaryFile(const char *name, bool error_on_failure);
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extern File PathNameOpenTemporaryFile(const char *name);
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extern bool PathNameDeleteTemporaryFile(const char *name, bool error_on_failure);
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extern void PathNameCreateTemporaryDir(const char *base, const char *name);
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extern void PathNameDeleteTemporaryDir(const char *name);
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extern void TempTablespacePath(char *path, Oid tablespace);
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/* Operations that allow use of regular stdio --- USE WITH CAUTION */
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extern FILE *AllocateFile(const char *name, const char *mode);
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extern int FreeFile(FILE *file);
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/* Operations that allow use of pipe streams (popen/pclose) */
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extern FILE *OpenPipeStream(const char *command, const char *mode);
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extern int ClosePipeStream(FILE *file);
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/* Operations to allow use of the <dirent.h> library routines */
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extern DIR *AllocateDir(const char *dirname);
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extern struct dirent *ReadDir(DIR *dir, const char *dirname);
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extern struct dirent *ReadDirExtended(DIR *dir, const char *dirname,
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int elevel);
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extern int FreeDir(DIR *dir);
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/* Operations to allow use of a plain kernel FD, with automatic cleanup */
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extern int OpenTransientFile(const char *fileName, int fileFlags);
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extern int OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
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extern int CloseTransientFile(int fd);
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/* If you've really really gotta have a plain kernel FD, use this */
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extern int BasicOpenFile(const char *fileName, int fileFlags);
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extern int BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
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/* Make a directory with default permissions */
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extern int MakePGDirectory(const char *directoryName);
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/* Miscellaneous support routines */
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extern void InitFileAccess(void);
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extern void set_max_safe_fds(void);
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extern void closeAllVfds(void);
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extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces);
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extern bool TempTablespacesAreSet(void);
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extern int GetTempTablespaces(Oid *tableSpaces, int numSpaces);
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extern Oid GetNextTempTableSpace(void);
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extern void AtEOXact_Files(bool isCommit);
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extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
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SubTransactionId parentSubid);
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extern void RemovePgTempFiles(void);
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extern void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok,
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bool unlink_all);
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extern bool looks_like_temp_rel_name(const char *name);
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extern int pg_fsync(int fd);
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extern int pg_fsync_no_writethrough(int fd);
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extern int pg_fsync_writethrough(int fd);
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extern int pg_fdatasync(int fd);
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extern void pg_flush_data(int fd, off_t offset, off_t amount);
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extern void fsync_fname(const char *fname, bool isdir);
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extern int durable_rename(const char *oldfile, const char *newfile, int loglevel);
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extern int durable_unlink(const char *fname, int loglevel);
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extern int durable_link_or_rename(const char *oldfile, const char *newfile, int loglevel);
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extern void SyncDataDirectory(void);
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extern int data_sync_elevel(int elevel);
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/* Filename components */
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#define PG_TEMP_FILES_DIR "pgsql_tmp"
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#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
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#endif /* FD_H */
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