1 files changed, 198 insertions, 0 deletions
diff --git a/src/include/storage/fd.h b/src/include/storage/fd.h
new file mode 100644
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--- /dev/null
+++ b/src/include/storage/fd.h
@@ -0,0 +1,198 @@
+/*-------------------------------------------------------------------------
+ *
+ * fd.h
+ *	  Virtual file descriptor definitions.
+ *
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/storage/fd.h
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/*
+ * calls:
+ *
+ *	File {Close, Read, Write, Size, 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);
+ *
+ *	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/CloseTransientFile for an
+ * unbuffered file descriptor.
+ *
+ * If you really can't use any of the above, at least call AcquireExternalFD
+ * or ReserveExternalFD to report any file descriptors that are held for any
+ * length of time.  Failure to do so risks unnecessary EMFILE errors.
+ */
+#ifndef FD_H
+#define FD_H
+
+#include <dirent.h>
+
+typedef enum RecoveryInitSyncMethod
+{
+	RECOVERY_INIT_SYNC_METHOD_FSYNC,
+	RECOVERY_INIT_SYNC_METHOD_SYNCFS
+}			RecoveryInitSyncMethod;
+
+struct iovec;					/* avoid including port/pg_iovec.h here */
+
+typedef int File;
+
+
+/* GUC parameter */
+extern PGDLLIMPORT int max_files_per_process;
+extern PGDLLIMPORT bool data_sync_retry;
+extern PGDLLIMPORT int recovery_init_sync_method;
+
+/*
+ * This is private to fd.c, but exported for save/restore_backend_variables()
+ */
+extern PGDLLIMPORT int max_safe_fds;
+
+/*
+ * On Windows, we have to interpret EACCES as possibly meaning the same as
+ * ENOENT, because if a file is unlinked-but-not-yet-gone on that platform,
+ * that's what you get.  Ugh.  This code is designed so that we don't
+ * actually believe these cases are okay without further evidence (namely,
+ * a pending fsync request getting canceled ... see ProcessSyncRequests).
+ */
+#ifndef WIN32
+#define FILE_POSSIBLY_DELETED(err)	((err) == ENOENT)
+#else
+#define FILE_POSSIBLY_DELETED(err)	((err) == ENOENT || (err) == EACCES)
+#endif
+
+/*
+ * O_DIRECT is not standard, but almost every Unix has it.  We translate it
+ * to the appropriate Windows flag in src/port/open.c.  We simulate it with
+ * fcntl(F_NOCACHE) on macOS inside fd.c's open() wrapper.  We use the name
+ * PG_O_DIRECT rather than defining O_DIRECT in that case (probably not a good
+ * idea on a Unix).
+ */
+#if defined(O_DIRECT)
+#define		PG_O_DIRECT O_DIRECT
+#elif defined(F_NOCACHE)
+#define		PG_O_DIRECT 0x80000000
+#define		PG_O_DIRECT_USE_F_NOCACHE
+#else
+#define		PG_O_DIRECT 0
+#endif
+
+/*
+ * prototypes for functions in fd.c
+ */
+
+/* Operations on virtual Files --- equivalent to Unix kernel file ops */
+extern File PathNameOpenFile(const char *fileName, int fileFlags);
+extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
+extern File OpenTemporaryFile(bool interXact);
+extern void FileClose(File file);
+extern int	FilePrefetch(File file, off_t offset, int amount, uint32 wait_event_info);
+extern int	FileRead(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info);
+extern int	FileWrite(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info);
+extern int	FileSync(File file, uint32 wait_event_info);
+extern off_t FileSize(File file);
+extern int	FileTruncate(File file, off_t offset, uint32 wait_event_info);
+extern void FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info);
+extern char *FilePathName(File file);
+extern int	FileGetRawDesc(File file);
+extern int	FileGetRawFlags(File file);
+extern mode_t FileGetRawMode(File file);
+
+/* Operations used for sharing named temporary files */
+extern File PathNameCreateTemporaryFile(const char *name, bool error_on_failure);
+extern File PathNameOpenTemporaryFile(const char *path, int mode);
+extern bool PathNameDeleteTemporaryFile(const char *name, bool error_on_failure);
+extern void PathNameCreateTemporaryDir(const char *base, const char *name);
+extern void PathNameDeleteTemporaryDir(const char *name);
+extern void TempTablespacePath(char *path, Oid tablespace);
+
+/* 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(const char *fileName, int fileFlags);
+extern int	OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
+extern int	CloseTransientFile(int fd);
+
+/* If you've really really gotta have a plain kernel FD, use this */
+extern int	BasicOpenFile(const char *fileName, int fileFlags);
+extern int	BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
+
+/* Use these for other cases, and also for long-lived BasicOpenFile FDs */
+extern bool AcquireExternalFD(void);
+extern void ReserveExternalFD(void);
+extern void ReleaseExternalFD(void);
+
+/* Make a directory with default permissions */
+extern int	MakePGDirectory(const char *directoryName);
+
+/* Miscellaneous support routines */
+extern void InitFileAccess(void);
+extern void InitTemporaryFileAccess(void);
+extern void set_max_safe_fds(void);
+extern void closeAllVfds(void);
+extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces);
+extern bool TempTablespacesAreSet(void);
+extern int	GetTempTablespaces(Oid *tableSpaces, int numSpaces);
+extern Oid	GetNextTempTableSpace(void);
+extern void AtEOXact_Files(bool isCommit);
+extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
+							  SubTransactionId parentSubid);
+extern void RemovePgTempFiles(void);
+extern void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok,
+								   bool unlink_all);
+extern bool looks_like_temp_rel_name(const char *name);
+
+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 ssize_t pg_pwritev_with_retry(int fd,
+									 const struct iovec *iov,
+									 int iovcnt,
+									 off_t offset);
+extern int	pg_truncate(const char *path, off_t length);
+extern void fsync_fname(const char *fname, bool isdir);
+extern int	fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel);
+extern int	durable_rename(const char *oldfile, const char *newfile, int loglevel);
+extern int	durable_unlink(const char *fname, int loglevel);
+extern int	durable_rename_excl(const char *oldfile, const char *newfile, int loglevel);
+extern void SyncDataDirectory(void);
+extern int	data_sync_elevel(int elevel);
+
+/* Filename components */
+#define PG_TEMP_FILES_DIR "pgsql_tmp"
+#define PG_TEMP_FILE_PREFIX "pgsql_tmp"
+
+#endif							/* FD_H */