1 /*------------------------------------------------------------------------- 2 * 3 * fd.h 4 * Virtual file descriptor definitions. 5 * 6 * 7 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group 8 * Portions Copyright (c) 1994, Regents of the University of California 9 * 10 * src/include/storage/fd.h 11 * 12 *------------------------------------------------------------------------- 13 */ 14 15 /* 16 * calls: 17 * 18 * File {Close, Read, Write, Size, Sync} 19 * {Path Name Open, Allocate, Free} File 20 * 21 * These are NOT JUST RENAMINGS OF THE UNIX ROUTINES. 22 * Use them for all file activity... 23 * 24 * File fd; 25 * fd = PathNameOpenFile("foo", O_RDONLY); 26 * 27 * AllocateFile(); 28 * FreeFile(); 29 * 30 * Use AllocateFile, not fopen, if you need a stdio file (FILE*); then 31 * use FreeFile, not fclose, to close it. AVOID using stdio for files 32 * that you intend to hold open for any length of time, since there is 33 * no way for them to share kernel file descriptors with other files. 34 * 35 * Likewise, use AllocateDir/FreeDir, not opendir/closedir, to allocate 36 * open directories (DIR*), and OpenTransientFile/CloseTransientFile for an 37 * unbuffered file descriptor. 38 */ 39 #ifndef FD_H 40 #define FD_H 41 42 #include <dirent.h> 43 44 45 typedef int File; 46 47 48 /* GUC parameter */ 49 extern PGDLLIMPORT int max_files_per_process; 50 extern PGDLLIMPORT bool data_sync_retry; 51 52 /* 53 * This is private to fd.c, but exported for save/restore_backend_variables() 54 */ 55 extern int max_safe_fds; 56 57 /* 58 * On Windows, we have to interpret EACCES as possibly meaning the same as 59 * ENOENT, because if a file is unlinked-but-not-yet-gone on that platform, 60 * that's what you get. Ugh. This code is designed so that we don't 61 * actually believe these cases are okay without further evidence (namely, 62 * a pending fsync request getting canceled ... see ProcessSyncRequests). 63 */ 64 #ifndef WIN32 65 #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT) 66 #else 67 #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES) 68 #endif 69 70 /* 71 * prototypes for functions in fd.c 72 */ 73 74 /* Operations on virtual Files --- equivalent to Unix kernel file ops */ 75 extern File PathNameOpenFile(const char *fileName, int fileFlags); 76 extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode); 77 extern File OpenTemporaryFile(bool interXact); 78 extern void FileClose(File file); 79 extern int FilePrefetch(File file, off_t offset, int amount, uint32 wait_event_info); 80 extern int FileRead(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info); 81 extern int FileWrite(File file, char *buffer, int amount, off_t offset, uint32 wait_event_info); 82 extern int FileSync(File file, uint32 wait_event_info); 83 extern off_t FileSize(File file); 84 extern int FileTruncate(File file, off_t offset, uint32 wait_event_info); 85 extern void FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info); 86 extern char *FilePathName(File file); 87 extern int FileGetRawDesc(File file); 88 extern int FileGetRawFlags(File file); 89 extern mode_t FileGetRawMode(File file); 90 91 /* Operations used for sharing named temporary files */ 92 extern File PathNameCreateTemporaryFile(const char *name, bool error_on_failure); 93 extern File PathNameOpenTemporaryFile(const char *name); 94 extern bool PathNameDeleteTemporaryFile(const char *name, bool error_on_failure); 95 extern void PathNameCreateTemporaryDir(const char *base, const char *name); 96 extern void PathNameDeleteTemporaryDir(const char *name); 97 extern void TempTablespacePath(char *path, Oid tablespace); 98 99 /* Operations that allow use of regular stdio --- USE WITH CAUTION */ 100 extern FILE *AllocateFile(const char *name, const char *mode); 101 extern int FreeFile(FILE *file); 102 103 /* Operations that allow use of pipe streams (popen/pclose) */ 104 extern FILE *OpenPipeStream(const char *command, const char *mode); 105 extern int ClosePipeStream(FILE *file); 106 107 /* Operations to allow use of the <dirent.h> library routines */ 108 extern DIR *AllocateDir(const char *dirname); 109 extern struct dirent *ReadDir(DIR *dir, const char *dirname); 110 extern struct dirent *ReadDirExtended(DIR *dir, const char *dirname, 111 int elevel); 112 extern int FreeDir(DIR *dir); 113 114 /* Operations to allow use of a plain kernel FD, with automatic cleanup */ 115 extern int OpenTransientFile(const char *fileName, int fileFlags); 116 extern int OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode); 117 extern int CloseTransientFile(int fd); 118 119 /* If you've really really gotta have a plain kernel FD, use this */ 120 extern int BasicOpenFile(const char *fileName, int fileFlags); 121 extern int BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode); 122 123 /* Make a directory with default permissions */ 124 extern int MakePGDirectory(const char *directoryName); 125 126 /* Miscellaneous support routines */ 127 extern void InitFileAccess(void); 128 extern void set_max_safe_fds(void); 129 extern void closeAllVfds(void); 130 extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces); 131 extern bool TempTablespacesAreSet(void); 132 extern int GetTempTablespaces(Oid *tableSpaces, int numSpaces); 133 extern Oid GetNextTempTableSpace(void); 134 extern void AtEOXact_Files(bool isCommit); 135 extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid, 136 SubTransactionId parentSubid); 137 extern void RemovePgTempFiles(void); 138 extern bool looks_like_temp_rel_name(const char *name); 139 140 extern int pg_fsync(int fd); 141 extern int pg_fsync_no_writethrough(int fd); 142 extern int pg_fsync_writethrough(int fd); 143 extern int pg_fdatasync(int fd); 144 extern void pg_flush_data(int fd, off_t offset, off_t amount); 145 extern void fsync_fname(const char *fname, bool isdir); 146 extern int durable_rename(const char *oldfile, const char *newfile, int loglevel); 147 extern int durable_unlink(const char *fname, int loglevel); 148 extern int durable_link_or_rename(const char *oldfile, const char *newfile, int loglevel); 149 extern void SyncDataDirectory(void); 150 extern int data_sync_elevel(int elevel); 151 152 /* Filename components */ 153 #define PG_TEMP_FILES_DIR "pgsql_tmp" 154 #define PG_TEMP_FILE_PREFIX "pgsql_tmp" 155 156 #endif /* FD_H */ 157