Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * fd.h
4 : : * Virtual file descriptor definitions.
5 : : *
6 : : *
7 : : * Portions Copyright (c) 1996-2024, 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, ReadV, Write, WriteV, 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 : : * If you really can't use any of the above, at least call AcquireExternalFD
40 : : * or ReserveExternalFD to report any file descriptors that are held for any
41 : : * length of time. Failure to do so risks unnecessary EMFILE errors.
42 : : */
43 : : #ifndef FD_H
44 : : #define FD_H
45 : :
46 : : #include "port/pg_iovec.h"
47 : :
48 : : #include <dirent.h>
49 : : #include <fcntl.h>
50 : :
51 : : typedef int File;
52 : :
53 : :
54 : : #define IO_DIRECT_DATA 0x01
55 : : #define IO_DIRECT_WAL 0x02
56 : : #define IO_DIRECT_WAL_INIT 0x04
57 : :
58 : :
59 : : /* GUC parameter */
60 : : extern PGDLLIMPORT int max_files_per_process;
61 : : extern PGDLLIMPORT bool data_sync_retry;
62 : : extern PGDLLIMPORT int recovery_init_sync_method;
63 : : extern PGDLLIMPORT int io_direct_flags;
64 : :
65 : : /*
66 : : * This is private to fd.c, but exported for save/restore_backend_variables()
67 : : */
68 : : extern PGDLLIMPORT int max_safe_fds;
69 : :
70 : : /*
71 : : * On Windows, we have to interpret EACCES as possibly meaning the same as
72 : : * ENOENT, because if a file is unlinked-but-not-yet-gone on that platform,
73 : : * that's what you get. Ugh. This code is designed so that we don't
74 : : * actually believe these cases are okay without further evidence (namely,
75 : : * a pending fsync request getting canceled ... see ProcessSyncRequests).
76 : : */
77 : : #ifndef WIN32
78 : : #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT)
79 : : #else
80 : : #define FILE_POSSIBLY_DELETED(err) ((err) == ENOENT || (err) == EACCES)
81 : : #endif
82 : :
83 : : /*
84 : : * O_DIRECT is not standard, but almost every Unix has it. We translate it
85 : : * to the appropriate Windows flag in src/port/open.c. We simulate it with
86 : : * fcntl(F_NOCACHE) on macOS inside fd.c's open() wrapper. We use the name
87 : : * PG_O_DIRECT rather than defining O_DIRECT in that case (probably not a good
88 : : * idea on a Unix). We can only use it if the compiler will correctly align
89 : : * PGIOAlignedBlock for us, though.
90 : : */
91 : : #if defined(O_DIRECT) && defined(pg_attribute_aligned)
92 : : #define PG_O_DIRECT O_DIRECT
93 : : #elif defined(F_NOCACHE)
94 : : #define PG_O_DIRECT 0x80000000
95 : : #define PG_O_DIRECT_USE_F_NOCACHE
96 : : #else
97 : : #define PG_O_DIRECT 0
98 : : #endif
99 : :
100 : : /*
101 : : * prototypes for functions in fd.c
102 : : */
103 : :
104 : : /* Operations on virtual Files --- equivalent to Unix kernel file ops */
105 : : extern File PathNameOpenFile(const char *fileName, int fileFlags);
106 : : extern File PathNameOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
107 : : extern File OpenTemporaryFile(bool interXact);
108 : : extern void FileClose(File file);
109 : : extern int FilePrefetch(File file, off_t offset, off_t amount, uint32 wait_event_info);
110 : : extern ssize_t FileReadV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
111 : : extern ssize_t FileWriteV(File file, const struct iovec *ioc, int iovcnt, off_t offset, uint32 wait_event_info);
112 : : extern int FileSync(File file, uint32 wait_event_info);
113 : : extern int FileZero(File file, off_t offset, off_t amount, uint32 wait_event_info);
114 : : extern int FileFallocate(File file, off_t offset, off_t amount, uint32 wait_event_info);
115 : :
116 : : extern off_t FileSize(File file);
117 : : extern int FileTruncate(File file, off_t offset, uint32 wait_event_info);
118 : : extern void FileWriteback(File file, off_t offset, off_t nbytes, uint32 wait_event_info);
119 : : extern char *FilePathName(File file);
120 : : extern int FileGetRawDesc(File file);
121 : : extern int FileGetRawFlags(File file);
122 : : extern mode_t FileGetRawMode(File file);
123 : :
124 : : /* Operations used for sharing named temporary files */
125 : : extern File PathNameCreateTemporaryFile(const char *path, bool error_on_failure);
126 : : extern File PathNameOpenTemporaryFile(const char *path, int mode);
127 : : extern bool PathNameDeleteTemporaryFile(const char *path, bool error_on_failure);
128 : : extern void PathNameCreateTemporaryDir(const char *basedir, const char *directory);
129 : : extern void PathNameDeleteTemporaryDir(const char *dirname);
130 : : extern void TempTablespacePath(char *path, Oid tablespace);
131 : :
132 : : /* Operations that allow use of regular stdio --- USE WITH CAUTION */
133 : : extern FILE *AllocateFile(const char *name, const char *mode);
134 : : extern int FreeFile(FILE *file);
135 : :
136 : : /* Operations that allow use of pipe streams (popen/pclose) */
137 : : extern FILE *OpenPipeStream(const char *command, const char *mode);
138 : : extern int ClosePipeStream(FILE *file);
139 : :
140 : : /* Operations to allow use of the <dirent.h> library routines */
141 : : extern DIR *AllocateDir(const char *dirname);
142 : : extern struct dirent *ReadDir(DIR *dir, const char *dirname);
143 : : extern struct dirent *ReadDirExtended(DIR *dir, const char *dirname,
144 : : int elevel);
145 : : extern int FreeDir(DIR *dir);
146 : :
147 : : /* Operations to allow use of a plain kernel FD, with automatic cleanup */
148 : : extern int OpenTransientFile(const char *fileName, int fileFlags);
149 : : extern int OpenTransientFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
150 : : extern int CloseTransientFile(int fd);
151 : :
152 : : /* If you've really really gotta have a plain kernel FD, use this */
153 : : extern int BasicOpenFile(const char *fileName, int fileFlags);
154 : : extern int BasicOpenFilePerm(const char *fileName, int fileFlags, mode_t fileMode);
155 : :
156 : : /* Use these for other cases, and also for long-lived BasicOpenFile FDs */
157 : : extern bool AcquireExternalFD(void);
158 : : extern void ReserveExternalFD(void);
159 : : extern void ReleaseExternalFD(void);
160 : :
161 : : /* Make a directory with default permissions */
162 : : extern int MakePGDirectory(const char *directoryName);
163 : :
164 : : /* Miscellaneous support routines */
165 : : extern void InitFileAccess(void);
166 : : extern void InitTemporaryFileAccess(void);
167 : : extern void set_max_safe_fds(void);
168 : : extern void closeAllVfds(void);
169 : : extern void SetTempTablespaces(Oid *tableSpaces, int numSpaces);
170 : : extern bool TempTablespacesAreSet(void);
171 : : extern int GetTempTablespaces(Oid *tableSpaces, int numSpaces);
172 : : extern Oid GetNextTempTableSpace(void);
173 : : extern void AtEOXact_Files(bool isCommit);
174 : : extern void AtEOSubXact_Files(bool isCommit, SubTransactionId mySubid,
175 : : SubTransactionId parentSubid);
176 : : extern void RemovePgTempFiles(void);
177 : : extern void RemovePgTempFilesInDir(const char *tmpdirname, bool missing_ok,
178 : : bool unlink_all);
179 : : extern bool looks_like_temp_rel_name(const char *name);
180 : :
181 : : extern int pg_fsync(int fd);
182 : : extern int pg_fsync_no_writethrough(int fd);
183 : : extern int pg_fsync_writethrough(int fd);
184 : : extern int pg_fdatasync(int fd);
185 : : extern bool pg_file_exists(const char *fname);
186 : : extern void pg_flush_data(int fd, off_t offset, off_t nbytes);
187 : : extern int pg_truncate(const char *path, off_t length);
188 : : extern void fsync_fname(const char *fname, bool isdir);
189 : : extern int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel);
190 : : extern int durable_rename(const char *oldfile, const char *newfile, int elevel);
191 : : extern int durable_unlink(const char *fname, int elevel);
192 : : extern void SyncDataDirectory(void);
193 : : extern int data_sync_elevel(int elevel);
194 : :
195 : : static inline ssize_t
124 tmunro@postgresql.or 196 :GNC 400406 : FileRead(File file, void *buffer, size_t amount, off_t offset,
197 : : uint32 wait_event_info)
198 : : {
199 : 400406 : struct iovec iov = {
200 : : .iov_base = buffer,
201 : : .iov_len = amount
202 : : };
203 : :
204 : 400406 : return FileReadV(file, &iov, 1, offset, wait_event_info);
205 : : }
206 : :
207 : : static inline ssize_t
208 : 174156 : FileWrite(File file, const void *buffer, size_t amount, off_t offset,
209 : : uint32 wait_event_info)
210 : : {
211 : 174156 : struct iovec iov = {
212 : 174156 : .iov_base = unconstify(void *, buffer),
213 : : .iov_len = amount
214 : : };
215 : :
216 : 174156 : return FileWriteV(file, &iov, 1, offset, wait_event_info);
217 : : }
218 : :
219 : : #endif /* FD_H */
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