src/port/open.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * open.c
   4  *         Win32 open() replacement
   5  *
   6  *
   7  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
   8  *
   9  * $PostgreSQL$
  10  *
  11  *-------------------------------------------------------------------------
  12  */
  13
  14 #ifdef WIN32
  15
  16 #ifndef FRONTEND
  17 #include "postgres.h"
  18 #else
  19 #include "postgres_fe.h"
  20 #endif
  21
  22 #include <windows.h>
  23 #include <fcntl.h>
  24 #include <assert.h>
  25
  26
  27 static int
  28 openFlagsToCreateFileFlags(int openFlags)
  29 {
  30         switch (openFlags & (O_CREAT | O_TRUNC | O_EXCL))
  31         {
  32                         /* O_EXCL is meaningless without O_CREAT */
  33                 case 0:
  34                 case O_EXCL:
  35                         return OPEN_EXISTING;
  36
  37                 case O_CREAT:
  38                         return OPEN_ALWAYS;
  39
  40                         /* O_EXCL is meaningless without O_CREAT */
  41                 case O_TRUNC:
  42                 case O_TRUNC | O_EXCL:
  43                         return TRUNCATE_EXISTING;
  44
  45                 case O_CREAT | O_TRUNC:
  46                         return CREATE_ALWAYS;
  47
  48                         /* O_TRUNC is meaningless with O_CREAT */
  49                 case O_CREAT | O_EXCL:
  50                 case O_CREAT | O_TRUNC | O_EXCL:
  51                         return CREATE_NEW;
  52         }
  53
  54         /* will never get here */
  55         return 0;
  56 }
  57
  58 /*
  59  *       - file attribute setting, based on fileMode?
  60  */
  61 int
  62 pgwin32_open(const char *fileName, int fileFlags,...)
  63 {
  64         int                     fd;
  65         HANDLE          h = INVALID_HANDLE_VALUE;
  66         SECURITY_ATTRIBUTES sa;
  67         int                     loops = 0;
  68
  69         /* Check that we can handle the request */
  70         assert((fileFlags & ((O_RDONLY | O_WRONLY | O_RDWR) | O_APPEND |
  71                                                  (O_RANDOM | O_SEQUENTIAL | O_TEMPORARY) |
  72                                                  _O_SHORT_LIVED | O_DSYNC | O_DIRECT |
  73                   (O_CREAT | O_TRUNC | O_EXCL) | (O_TEXT | O_BINARY))) == fileFlags);
  74
  75         sa.nLength = sizeof(sa);
  76         sa.bInheritHandle = TRUE;
  77         sa.lpSecurityDescriptor = NULL;
  78
  79         while ((h = CreateFile(fileName,
  80         /* cannot use O_RDONLY, as it == 0 */
  81                                           (fileFlags & O_RDWR) ? (GENERIC_WRITE | GENERIC_READ) :
  82                                          ((fileFlags & O_WRONLY) ? GENERIC_WRITE : GENERIC_READ),
  83         /* These flags allow concurrent rename/unlink */
  84                                         (FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE),
  85                                                 &sa,
  86                                                 openFlagsToCreateFileFlags(fileFlags),
  87                                                 FILE_ATTRIBUTE_NORMAL |
  88                                          ((fileFlags & O_RANDOM) ? FILE_FLAG_RANDOM_ACCESS : 0) |
  89                            ((fileFlags & O_SEQUENTIAL) ? FILE_FLAG_SEQUENTIAL_SCAN : 0) |
  90                           ((fileFlags & _O_SHORT_LIVED) ? FILE_ATTRIBUTE_TEMPORARY : 0) |
  91                                 ((fileFlags & O_TEMPORARY) ? FILE_FLAG_DELETE_ON_CLOSE : 0) |
  92                                           ((fileFlags & O_DIRECT) ? FILE_FLAG_NO_BUFFERING : 0) |
  93                                                 ((fileFlags & O_DSYNC) ? FILE_FLAG_WRITE_THROUGH : 0),
  94                                                 NULL)) == INVALID_HANDLE_VALUE)
  95         {
  96                 /*
  97                  * Sharing violation or locking error can indicate antivirus, backup
  98                  * or similar software that's locking the file. Try again for 30 seconds
  99                  * before giving up.
 100                  */
 101                 DWORD err = GetLastError();
 102                 if (err == ERROR_SHARING_VIOLATION ||
 103                         err == ERROR_LOCK_VIOLATION)
 104                 {
 105                         pg_usleep(100000);
 106                         loops++;
 107
 108 #ifndef FRONTEND
 109                         if (loops == 50)
 110                                 ereport(LOG,
 111                                     (errmsg("could not open file \"%s\": %s", fileName,
 112                                           (err == ERROR_SHARING_VIOLATION)?_("sharing violation"):_("lock violation")),
 113                                          errdetail("Continuing to retry for 30 seconds."),
 114                                          errhint("You might have antivirus, backup, or similar software interfering with the database system.")));
 115 #endif
 116
 117                         if (loops < 300)
 118                                 continue;
 119                 }
 120
 121                 _dosmaperr(err);
 122                 return -1;
 123         }
 124
 125         /* _open_osfhandle will, on error, set errno accordingly */
 126         if ((fd = _open_osfhandle((long) h, fileFlags & O_APPEND)) < 0)
 127                 CloseHandle(h);                 /* will not affect errno */
 128         else if (fileFlags & (O_TEXT | O_BINARY) &&
 129                          _setmode(fd, fileFlags & (O_TEXT | O_BINARY)) < 0)
 130         {
 131                 _close(fd);
 132                 return -1;
 133         }
 134
 135         return fd;
 136 }
 137
 138 FILE *
 139 pgwin32_fopen(const char *fileName, const char *mode)
 140 {
 141         int                     openmode = 0;
 142         int                     fd;
 143
 144         if (strstr(mode, "r+"))
 145                 openmode |= O_RDWR;
 146         else if (strchr(mode, 'r'))
 147                 openmode |= O_RDONLY;
 148         if (strstr(mode, "w+"))
 149                 openmode |= O_RDWR | O_CREAT | O_TRUNC;
 150         else if (strchr(mode, 'w'))
 151                 openmode |= O_WRONLY | O_CREAT | O_TRUNC;
 152         if (strchr(mode, 'a'))
 153                 openmode |= O_WRONLY | O_CREAT | O_APPEND;
 154
 155         if (strchr(mode, 'b'))
 156                 openmode |= O_BINARY;
 157         if (strchr(mode, 't'))
 158                 openmode |= O_TEXT;
 159
 160         fd = pgwin32_open(fileName, openmode);
 161         if (fd == -1)
 162                 return NULL;
 163         return _fdopen(fd, mode);
 164 }
 165
 166 #endif