1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/*-------------------------------------------------------------------------
*
* open.c
* Win32 open() replacement
*
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
*
* src/port/open.c
*
*-------------------------------------------------------------------------
*/
#ifdef WIN32
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include <fcntl.h>
#include <assert.h>
#include <sys/stat.h>
static int
openFlagsToCreateFileFlags(int openFlags)
{
switch (openFlags & (O_CREAT | O_TRUNC | O_EXCL))
{
/* O_EXCL is meaningless without O_CREAT */
case 0:
case O_EXCL:
return OPEN_EXISTING;
case O_CREAT:
return OPEN_ALWAYS;
/* O_EXCL is meaningless without O_CREAT */
case O_TRUNC:
case O_TRUNC | O_EXCL:
return TRUNCATE_EXISTING;
case O_CREAT | O_TRUNC:
return CREATE_ALWAYS;
/* O_TRUNC is meaningless with O_CREAT */
case O_CREAT | O_EXCL:
case O_CREAT | O_TRUNC | O_EXCL:
return CREATE_NEW;
}
/* will never get here */
return 0;
}
/*
* - file attribute setting, based on fileMode?
*/
int
pgwin32_open(const char *fileName, int fileFlags,...)
{
int fd;
HANDLE h = INVALID_HANDLE_VALUE;
SECURITY_ATTRIBUTES sa;
int loops = 0;
/* Check that we can handle the request */
assert((fileFlags & ((O_RDONLY | O_WRONLY | O_RDWR) | O_APPEND |
(O_RANDOM | O_SEQUENTIAL | O_TEMPORARY) |
_O_SHORT_LIVED | O_DSYNC | O_DIRECT |
(O_CREAT | O_TRUNC | O_EXCL) | (O_TEXT | O_BINARY))) == fileFlags);
#ifndef FRONTEND
Assert(pgwin32_signal_event != NULL); /* small chance of pg_usleep() */
#endif
#ifdef FRONTEND
/*
* Since PostgreSQL 12, those concurrent-safe versions of open() and
* fopen() can be used by frontends, having as side-effect to switch the
* file-translation mode from O_TEXT to O_BINARY if none is specified.
* Caller may want to enforce the binary or text mode, but if nothing is
* defined make sure that the default mode maps with what versions older
* than 12 have been doing.
*/
if ((fileFlags & O_BINARY) == 0)
fileFlags |= O_TEXT;
#endif
sa.nLength = sizeof(sa);
sa.bInheritHandle = TRUE;
sa.lpSecurityDescriptor = NULL;
while ((h = CreateFile(fileName,
/* cannot use O_RDONLY, as it == 0 */
(fileFlags & O_RDWR) ? (GENERIC_WRITE | GENERIC_READ) :
((fileFlags & O_WRONLY) ? GENERIC_WRITE : GENERIC_READ),
/* These flags allow concurrent rename/unlink */
(FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
&sa,
openFlagsToCreateFileFlags(fileFlags),
FILE_ATTRIBUTE_NORMAL |
((fileFlags & O_RANDOM) ? FILE_FLAG_RANDOM_ACCESS : 0) |
((fileFlags & O_SEQUENTIAL) ? FILE_FLAG_SEQUENTIAL_SCAN : 0) |
((fileFlags & _O_SHORT_LIVED) ? FILE_ATTRIBUTE_TEMPORARY : 0) |
((fileFlags & O_TEMPORARY) ? FILE_FLAG_DELETE_ON_CLOSE : 0) |
((fileFlags & O_DIRECT) ? FILE_FLAG_NO_BUFFERING : 0) |
((fileFlags & O_DSYNC) ? FILE_FLAG_WRITE_THROUGH : 0),
NULL)) == INVALID_HANDLE_VALUE)
{
/*
* Sharing violation or locking error can indicate antivirus, backup
* or similar software that's locking the file. Wait a bit and try
* again, giving up after 30 seconds.
*/
DWORD err = GetLastError();
if (err == ERROR_SHARING_VIOLATION ||
err == ERROR_LOCK_VIOLATION)
{
#ifndef FRONTEND
if (loops == 50)
ereport(LOG,
(errmsg("could not open file \"%s\": %s", fileName,
(err == ERROR_SHARING_VIOLATION) ? _("sharing violation") : _("lock violation")),
errdetail("Continuing to retry for 30 seconds."),
errhint("You might have antivirus, backup, or similar software interfering with the database system.")));
#endif
if (loops < 300)
{
pg_usleep(100000);
loops++;
continue;
}
}
/*
* ERROR_ACCESS_DENIED is returned if the file is deleted but not yet
* gone (Windows NT status code is STATUS_DELETE_PENDING). In that
* case we want to wait a bit and try again, giving up after 1 second
* (since this condition should never persist very long). However,
* there are other commonly-hit cases that return ERROR_ACCESS_DENIED,
* so care is needed. In particular that happens if we try to open a
* directory, or of course if there's an actual file-permissions
* problem. To distinguish these cases, try a stat(). In the
* delete-pending case, it will either also get STATUS_DELETE_PENDING,
* or it will see the file as gone and fail with ENOENT. In other
* cases it will usually succeed. The only somewhat-likely case where
* this coding will uselessly wait is if there's a permissions problem
* with a containing directory, which we hope will never happen in any
* performance-critical code paths.
*/
if (err == ERROR_ACCESS_DENIED)
{
if (loops < 10)
{
struct stat st;
if (stat(fileName, &st) != 0)
{
pg_usleep(100000);
loops++;
continue;
}
}
}
_dosmaperr(err);
return -1;
}
/* _open_osfhandle will, on error, set errno accordingly */
if ((fd = _open_osfhandle((intptr_t) h, fileFlags & O_APPEND)) < 0)
CloseHandle(h); /* will not affect errno */
else if (fileFlags & (O_TEXT | O_BINARY) &&
_setmode(fd, fileFlags & (O_TEXT | O_BINARY)) < 0)
{
_close(fd);
return -1;
}
return fd;
}
FILE *
pgwin32_fopen(const char *fileName, const char *mode)
{
int openmode = 0;
int fd;
if (strstr(mode, "r+"))
openmode |= O_RDWR;
else if (strchr(mode, 'r'))
openmode |= O_RDONLY;
if (strstr(mode, "w+"))
openmode |= O_RDWR | O_CREAT | O_TRUNC;
else if (strchr(mode, 'w'))
openmode |= O_WRONLY | O_CREAT | O_TRUNC;
if (strchr(mode, 'a'))
openmode |= O_WRONLY | O_CREAT | O_APPEND;
if (strchr(mode, 'b'))
openmode |= O_BINARY;
if (strchr(mode, 't'))
openmode |= O_TEXT;
fd = pgwin32_open(fileName, openmode);
if (fd == -1)
return NULL;
return _fdopen(fd, mode);
}
#endif
|
