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0c5803b450
The file handling functions from fd.c were called with a diverse mix of notations for the file permissions when they were opening new files. Almost all files created by the server should have the same permissions set. So change the API so that e.g. OpenTransientFile() automatically uses the standard permissions set, and OpenTransientFilePerm() is a new function that takes an explicit permissions set for the few cases where it is needed. This also saves an unnecessary argument for call sites that are just opening an existing file. While we're reviewing these APIs, get rid of the FileName typedef and use the standard const char * for the file name and mode_t for the file mode. This makes these functions match other file handling functions and removes an unnecessary layer of mysteriousness. We can also get rid of a few casts that way. Author: David Steele <david@pgmasters.net>
131 lines
4.6 KiB
C
131 lines
4.6 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) 1996-2017, 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, Seek, Tell, 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/CloseTransient File 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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/*
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* FileSeek uses the standard UNIX lseek(2) flags.
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*/
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typedef int File;
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/* GUC parameter */
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extern int max_files_per_process;
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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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* 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, uint32 wait_event_info);
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extern int FileWrite(File file, char *buffer, int amount, uint32 wait_event_info);
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extern int FileSync(File file, uint32 wait_event_info);
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extern off_t FileSeek(File file, off_t offset, int whence);
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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 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 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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/* 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 Oid GetNextTempTableSpace(void);
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extern void AtEOXact_Files(void);
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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 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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/* Filename components for OpenTemporaryFile */
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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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