src/port/win32stat.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * win32stat.c
   4  *        Replacements for <sys/stat.h> functions using GetFileInformationByHandle
   5  *
   6  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/port/win32stat.c
  12  *
  13  *-------------------------------------------------------------------------
  14  */
  15
  16 #ifdef WIN32
  17
  18 #include "c.h"
  19 #include <windows.h>
  20
  21 /*
  22  * Convert a FILETIME struct into a 64 bit time_t.
  23  */
  24 static __time64_t
  25 filetime_to_time(const FILETIME *ft)
  26 {
  27         ULARGE_INTEGER unified_ft = {0};
  28         static const uint64 EpochShift = UINT64CONST(116444736000000000);
  29
  30         unified_ft.LowPart = ft->dwLowDateTime;
  31         unified_ft.HighPart = ft->dwHighDateTime;
  32
  33         if (unified_ft.QuadPart < EpochShift)
  34                 return -1;
  35
  36         unified_ft.QuadPart -= EpochShift;
  37         unified_ft.QuadPart /= 10 * 1000 * 1000;
  38
  39         return unified_ft.QuadPart;
  40 }
  41
  42 /*
  43  * Convert WIN32 file attributes to a Unix-style mode.
  44  *
  45  * Only owner permissions are set.
  46  */
  47 static unsigned short
  48 fileattr_to_unixmode(int attr)
  49 {
  50         unsigned short uxmode = 0;
  51
  52         uxmode |= (unsigned short) ((attr & FILE_ATTRIBUTE_DIRECTORY) ?
  53                                                                 (_S_IFDIR) : (_S_IFREG));
  54
  55         uxmode |= (unsigned short) ((attr & FILE_ATTRIBUTE_READONLY) ?
  56                                                                 (_S_IREAD) : (_S_IREAD | _S_IWRITE));
  57
  58         /* there is no need to simulate _S_IEXEC using CMD's PATHEXT extensions */
  59         uxmode |= _S_IEXEC;
  60
  61         return uxmode;
  62 }
  63
  64 /*
  65  * Convert WIN32 file information (from a HANDLE) to a struct stat.
  66  */
  67 static int
  68 fileinfo_to_stat(HANDLE hFile, struct stat *buf)
  69 {
  70         BY_HANDLE_FILE_INFORMATION fiData;
  71
  72         memset(buf, 0, sizeof(*buf));
  73
  74         /*
  75          * GetFileInformationByHandle minimum supported version: Windows XP and
  76          * Windows Server 2003, so it exists everywhere we care about.
  77          */
  78         if (!GetFileInformationByHandle(hFile, &fiData))
  79         {
  80                 _dosmaperr(GetLastError());
  81                 return -1;
  82         }
  83
  84         if (fiData.ftLastWriteTime.dwLowDateTime ||
  85                 fiData.ftLastWriteTime.dwHighDateTime)
  86                 buf->st_mtime = filetime_to_time(&fiData.ftLastWriteTime);
  87
  88         if (fiData.ftLastAccessTime.dwLowDateTime ||
  89                 fiData.ftLastAccessTime.dwHighDateTime)
  90                 buf->st_atime = filetime_to_time(&fiData.ftLastAccessTime);
  91         else
  92                 buf->st_atime = buf->st_mtime;
  93
  94         if (fiData.ftCreationTime.dwLowDateTime ||
  95                 fiData.ftCreationTime.dwHighDateTime)
  96                 buf->st_ctime = filetime_to_time(&fiData.ftCreationTime);
  97         else
  98                 buf->st_ctime = buf->st_mtime;
  99
 100         buf->st_mode = fileattr_to_unixmode(fiData.dwFileAttributes);
 101         buf->st_nlink = fiData.nNumberOfLinks;
 102
 103         buf->st_size = ((((uint64) fiData.nFileSizeHigh) << 32) |
 104                                         fiData.nFileSizeLow);
 105
 106         return 0;
 107 }
 108
 109 /*
 110  * Windows implementation of stat().
 111  *
 112  * This currently also implements lstat(), though perhaps that should change.
 113  */
 114 int
 115 _pgstat64(const char *name, struct stat *buf)
 116 {
 117         /*
 118          * Our open wrapper will report STATUS_DELETE_PENDING as ENOENT.  We
 119          * request FILE_FLAG_BACKUP_SEMANTICS so that we can open directories too,
 120          * for limited purposes.  We use the private handle-based version, so we
 121          * don't risk running out of fds.
 122          */
 123         HANDLE          hFile;
 124         int                     ret;
 125
 126         hFile = pgwin32_open_handle(name, O_RDONLY, true);
 127         if (hFile == INVALID_HANDLE_VALUE)
 128                 return -1;
 129
 130         ret = fileinfo_to_stat(hFile, buf);
 131
 132         CloseHandle(hFile);
 133         return ret;
 134 }
 135
 136 /*
 137  * Windows implementation of fstat().
 138  */
 139 int
 140 _pgfstat64(int fileno, struct stat *buf)
 141 {
 142         HANDLE          hFile = (HANDLE) _get_osfhandle(fileno);
 143         BY_HANDLE_FILE_INFORMATION fiData;
 144
 145         if (hFile == INVALID_HANDLE_VALUE || buf == NULL)
 146         {
 147                 errno = EINVAL;
 148                 return -1;
 149         }
 150
 151         /*
 152          * Check if the fileno is a data stream.  If so, unless it has been
 153          * redirected to a file, getting information through its HANDLE will fail,
 154          * so emulate its stat information in the most appropriate way and return
 155          * it instead.
 156          */
 157         if ((fileno == _fileno(stdin) ||
 158                  fileno == _fileno(stdout) ||
 159                  fileno == _fileno(stderr)) &&
 160                 !GetFileInformationByHandle(hFile, &fiData))
 161         {
 162                 memset(buf, 0, sizeof(*buf));
 163                 buf->st_mode = _S_IFCHR;
 164                 buf->st_dev = fileno;
 165                 buf->st_rdev = fileno;
 166                 buf->st_nlink = 1;
 167                 return 0;
 168         }
 169
 170         return fileinfo_to_stat(hFile, buf);
 171 }
 172
 173 #endif                                                  /* WIN32 */