winsup/cygwin/fhandler/cygdrive.cc

   1 /* fhandler_cygdrive.cc
   2
   3 This file is part of Cygwin.
   4
   5 This software is a copyrighted work licensed under the terms of the
   6 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   7 details. */
   8
   9 #include "winsup.h"
  10 #include <lm.h>
  11 #include <sys/statvfs.h>
  12 #include "cygerrno.h"
  13 #include "security.h"
  14 #include "path.h"
  15 #include "fhandler.h"
  16 #include "dtable.h"
  17 #include "cygheap.h"
  18 #include "shared_info.h"
  19
  20 #define _LIBC
  21 #include <dirent.h>
  22
  23 fhandler_cygdrive::fhandler_cygdrive () :
  24   fhandler_disk_file ()
  25 {
  26 }
  27
  28 int
  29 fhandler_cygdrive::open (int flags, mode_t mode)
  30 {
  31   if ((flags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
  32     {
  33       set_errno (EEXIST);
  34       return 0;
  35     }
  36   if (flags & O_WRONLY)
  37     {
  38       set_errno (EISDIR);
  39       return 0;
  40     }
  41   /* Open a fake handle to \\Device\\Null */
  42   return open_null (flags);
  43 }
  44
  45 int
  46 fhandler_cygdrive::fstat (struct stat *buf)
  47 {
  48   fhandler_base::fstat (buf);
  49   buf->st_ino = 2;
  50   buf->st_mode = S_IFDIR | STD_RBITS | STD_XBITS;
  51   buf->st_nlink = 1;
  52   return 0;
  53 }
  54
  55 int
  56 fhandler_cygdrive::fstatvfs (struct statvfs *sfs)
  57 {
  58   /* Virtual file system.  Just return an empty buffer with a few values
  59      set to something useful.  Just as on Linux. */
  60   memset (sfs, 0, sizeof (*sfs));
  61   sfs->f_bsize = sfs->f_frsize = 4096;
  62   sfs->f_flag = ST_RDONLY;
  63   sfs->f_namemax = NAME_MAX;
  64   return 0;
  65 }
  66
  67 #define MAX_DRIVE_BUF_LEN       (sizeof ("x:\\") * 26 + 2)
  68
  69 struct __DIR_drives
  70 {
  71   char *pdrive;
  72   char  pbuf[MAX_DRIVE_BUF_LEN];
  73 };
  74
  75 #define d_drives(d)     ((__DIR_drives *) (d)->__d_internal)
  76
  77 DIR *
  78 fhandler_cygdrive::opendir (int fd)
  79 {
  80   DIR *dir;
  81
  82   dir = fhandler_disk_file::opendir (fd);
  83   if (dir)
  84     {
  85       dir->__d_internal = (uintptr_t) new __DIR_drives;
  86       GetLogicalDriveStrings (MAX_DRIVE_BUF_LEN, d_drives(dir)->pbuf);
  87       d_drives(dir)->pdrive = d_drives(dir)->pbuf;
  88     }
  89
  90   return dir;
  91 }
  92
  93 int
  94 fhandler_cygdrive::readdir (DIR *dir, dirent *de)
  95 {
  96   WCHAR drive[] = L"X:";
  97
  98   while (true)
  99     {
 100       if (!d_drives(dir)->pdrive || !*d_drives(dir)->pdrive)
 101         {
 102           if (!(dir->__flags & dirent_saw_dot))
 103             {
 104               de->d_name[0] = '.';
 105               de->d_name[1] = '\0';
 106               de->d_ino = 2;
 107             }
 108           return ENMFILE;
 109         }
 110       disk_type dt = get_disk_type ((drive[0] = *d_drives(dir)->pdrive, drive));
 111       if (dt == DT_SHARE_SMB)
 112         {
 113           /* Calling NetUseGetInfo on SMB drives allows to fetch the
 114              current state of the drive without trying to open a file
 115              descriptor on the share (GetFileAttributes).  This avoids
 116              waiting for SMB timeouts.  Of course, there's a downside:
 117              If a drive becomes availabe again, it can take a couple of
 118              minutes to recognize it. As long as this didn't happen,
 119              the drive will not show up in the cygdrive dir. */
 120           PUSE_INFO_1 pui1;
 121           DWORD status;
 122
 123           if (NetUseGetInfo (NULL, drive, 1, (PBYTE *) &pui1) == NERR_Success)
 124             {
 125               status = pui1->ui1_status;
 126               NetApiBufferFree (pui1);
 127               if (status == USE_OK)
 128                 break;
 129             }
 130         }
 131       else if (dt != DT_FLOPPY
 132                && GetFileAttributes (d_drives(dir)->pdrive) != INVALID_FILE_ATTRIBUTES)
 133         break;
 134       d_drives(dir)->pdrive = strchr (d_drives(dir)->pdrive, '\0') + 1;
 135     }
 136   *de->d_name = cyg_tolower (*d_drives(dir)->pdrive);
 137   de->d_name[1] = '\0';
 138   user_shared->warned_msdos = true;
 139   de->d_ino = readdir_get_ino (d_drives(dir)->pdrive, false);
 140   dir->__d_position++;
 141   d_drives(dir)->pdrive = strchr (d_drives(dir)->pdrive, '\0') + 1;
 142   syscall_printf ("%p = readdir (%p) (%s)", &de, dir, de->d_name);
 143   return 0;
 144 }
 145
 146 void
 147 fhandler_cygdrive::rewinddir (DIR *dir)
 148 {
 149   d_drives(dir)->pdrive = d_drives(dir)->pbuf;
 150   dir->__d_position = 0;
 151 }
 152
 153 int
 154 fhandler_cygdrive::closedir (DIR *dir)
 155 {
 156   delete d_drives(dir);
 157   return 0;
 158 }