* fhandler_floppy.cc (fhandler_dev_floppy::lseek): Determine

drive geometry or partition size to allow seeking from the end of
raw floppy device. Don't allow positioning past the end of media or
to offsets bigger then max off_t.

winsup/cygwin/ChangeLog

@@ -1,3 +1,10 @@
+2001-02-28  Egor Duda  <deo@logos-m.ru>
+
+	* fhandler_floppy.cc (fhandler_dev_floppy::lseek): Determine
+	drive geometry or partition size to allow seeking from the end of
+	raw floppy device. Don't allow positioning past the end of media or
+	to offsets bigger then max off_t.
+
 2001-02-27  Egor Duda  <deo@logos-m.ru>
 
 	* fhandler.h (class fhandler_console): Make all variables that

winsup/cygwin/fhandler_floppy.cc

@@ -16,6 +16,7 @@ details. */
 #include <unistd.h>
 #include "fhandler.h"
 #include "cygerrno.h"
+#include <winioctl.h>
 
 /**********************************************************************/
 /* fhandler_dev_floppy */
@@ -80,78 +81,114 @@ off_t
 fhandler_dev_floppy::lseek (off_t offset, int whence)
 {
   int ret;
-  DWORD off;
   char buf[512];
+  long long drive_size = 0;
+  long long lloffset = offset;
+  long long current_position;
+  off_t sector_aligned_offset;
+  off_t bytes_left;
+  DWORD low;
+  LONG high = 0;
 
-  if (whence == SEEK_SET)
+  if (os_being_run == winNT)
     {
-      if (offset < 0)
+      DISK_GEOMETRY di;
-        {
+      PARTITION_INFORMATION pi;
-	  set_errno (EINVAL);
+      DWORD bytes_read;
-	  return -1;
-	}
 
-      /* Invalidate buffer. */
+      if ( !DeviceIoControl ( get_handle(),
-      ret = writebuf ();
+                              IOCTL_DISK_GET_DRIVE_GEOMETRY,
-      if (ret)
+                              NULL, 0,
-	return ret;
+                              &di, sizeof (di),
-      devbufstart = devbufend = 0;
+                              &bytes_read, NULL) )
-
-      off = (offset / 512) * 512;
-
-      if (SetFilePointer (get_handle (), off, NULL, FILE_BEGIN)
-          == INVALID_SET_FILE_POINTER)
         {
           __seterrno ();
           return -1;
         }
-      return raw_read (buf, offset - off);
+      debug_printf ( "disk geometry: (%ld cyl)*(%ld trk)*(%ld sec)*(%ld bps)",
-    }
+                     di.Cylinders.LowPart,
-  else if (whence == SEEK_CUR)
+                     di.TracksPerCylinder,
+                     di.SectorsPerTrack,
+                     di.BytesPerSector );
+      if ( DeviceIoControl ( get_handle (),
+                             IOCTL_DISK_GET_PARTITION_INFO,
+                             NULL, 0,
+                             &pi, sizeof (pi),
+                             &bytes_read, NULL ))
         {
-      DWORD low;
+          debug_printf ( "partition info: %ld (%ld)",
-      LONG high = 0;
+                          pi.StartingOffset.LowPart,
+                          pi.PartitionLength.LowPart);
+          drive_size = (long long) pi.PartitionLength.QuadPart;
+        }
+      else
+        {
+          drive_size = (long long) di.Cylinders.QuadPart * di.TracksPerCylinder *
+                       di.SectorsPerTrack * di.BytesPerSector;
+        }
+      debug_printf ( "drive size: %ld", drive_size );
+    }
 
+  if (whence == SEEK_END && drive_size > 0)
+    {
+      lloffset = offset + drive_size;
+      whence = SEEK_SET; 
+    }
+
+  if (whence == SEEK_CUR)
+    {
       low = SetFilePointer (get_handle (), 0, &high, FILE_CURRENT);
       if (low == INVALID_SET_FILE_POINTER && GetLastError ())
 	{
 	  __seterrno ();
 	  return -1;
 	}
-      long long cur = (long long) high << 32 + low;
+      current_position = (long long) low + ((long long) high << 32);
       if (is_writing)
-	cur += devbufend - devbufstart;
+	current_position += devbufend - devbufstart;
       else
-	cur -= devbufend - devbufstart;
+	current_position -= devbufend - devbufstart;
 
+      lloffset += current_position;
+      whence = SEEK_SET;
+    }
+
+  if (lloffset < 0 ||
+      drive_size > 0 && lloffset > drive_size)
+    {
+      set_errno (EINVAL);
+      return -1;
+    }
+  high = lloffset >> 32;
+  low = lloffset & 0xffffffff;
+  if ( high || (off_t) low < 0 )
+    {
+      set_errno (EFBIG);
+      return -1;
+    }
+  offset = (off_t) low;
+
+  /* FIXME: sector can possibly be not 512 bytes long */
+  sector_aligned_offset = (offset / 512) * 512;
+  bytes_left = offset - sector_aligned_offset;
+
+  if (whence == SEEK_SET)
+    {
       /* Invalidate buffer. */
       ret = writebuf ();
       if (ret)
 	return ret;
       devbufstart = devbufend = 0;
 
-      cur += offset;
+      if (SetFilePointer (get_handle (), sector_aligned_offset, NULL, FILE_BEGIN)
-      if (cur < 0)
+          == INVALID_SET_FILE_POINTER)
-	{
-	  set_errno (EINVAL);
-	  return -1;
-	}
-
-      long long set = (cur / 512) * 512;
-      high = set >> 32;
-      low = set & 0xffffffff;
-
-      off = cur - set;
-
-      low = SetFilePointer (get_handle (), low, &high, FILE_BEGIN);
-      if (low == INVALID_SET_FILE_POINTER && GetLastError ())
         {
 	  __seterrno ();
 	  return -1;
 	}
-      return raw_read (buf, off);
+      return sector_aligned_offset + raw_read (buf, bytes_left);
     }
-  /* SEEK_END is not supported on raw disk devices. */
+
   set_errno (EINVAL);
   return -1;
 }