1 files changed, 119 insertions, 0 deletions
diff --git a/winsup/mingw/mingwex/mingw-fseek.c b/winsup/mingw/mingwex/mingw-fseek.c
new file mode 100644
index 000000000..6a3b66119
--- /dev/null
+++ b/winsup/mingw/mingwex/mingw-fseek.c
@@ -0,0 +1,119 @@
+/*
+ * Workaround for limitations on win9x where a file contents are
+ * not zero'd out if you seek past the end and then write.
+ * Copied from ming local-patch to binutils/bfd/libbfd.c written by
+ * Mumit Khan  <khan@xraylith.wisc.edu> 
+ */
+
+#include <windows.h>
+#include <stdio.h>
+#include <io.h>
+
+#ifdef __GNUC__
+# define INLINE __inline__
+#elif defined _MSC_VER
+# define INLINE __inline
+#else 
+# define INLINE
+#endif
+
+#define ZEROBLOCKSIZE 512
+static int __mingw_fseek_called;
+
+/* FIXME: put this in startup code and make os_platform_id global?
+   Or just get _osver from msvcrt.dll and bitest (_osver & 0x8000)? */
+
+INLINE 
+static
+int
+__mingw_is_win9x (void)
+{
+  static DWORD os_platform_id =  -1 ;
+
+  if (os_platform_id == -1)
+    {
+      OSVERSIONINFO os_version_info;
+      memset (&os_version_info, 0, sizeof (OSVERSIONINFO));
+      os_version_info.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
+      GetVersionEx (&os_version_info);
+
+      os_platform_id = os_version_info.dwPlatformId;
+    }
+ 
+  /* Don't even bother to check for Win32s. */
+  return os_platform_id == VER_PLATFORM_WIN32_WINDOWS;
+}
+
+/* The fseek in Win9x runtime does not zero out the file if seeking past
+   the end; if you don't want random stuff from your disk included in your
+   output DLL/executable, use this version instead. On WinNT/Win2k, it
+   just calls runtime fseek().  
+   
+   CHECK/FIXME: Does this work for both text and binary modes?? */ 
+
+
+int
+__mingw_fseek (FILE *fp, long offset, int whence)
+{
+# undef fseek 
+  __mingw_fseek_called = 1;
+  return fseek (fp, offset, whence);
+}
+
+int
+__mingw_fwrite (const void *buffer, size_t size, size_t count, FILE *fp)
+{
+# undef fwrite 
+  if ( __mingw_is_win9x () &&  __mingw_fseek_called)
+    {
+      DWORD actual_length, current_position;
+      __mingw_fseek_called = 0;
+      fflush (fp);
+      actual_length = GetFileSize ((HANDLE) _get_osfhandle (fileno (fp)), 
+                                   NULL);
+      current_position = SetFilePointer ((HANDLE) _get_osfhandle (fileno (fp)),
+                                         0, 0, FILE_CURRENT);
+#ifdef DEBUG
+      printf ("__mingw_fwrite: current %ld, actual %ld\n", 
+	      current_position, actual_length);
+#endif /* DEBUG */
+      if (current_position > actual_length)
+	{
+	  static char __mingw_zeros[ZEROBLOCKSIZE];
+	  long numleft;
+
+	  SetFilePointer ((HANDLE) _get_osfhandle (fileno (fp)), 
+	                  0, 0, FILE_END);
+	  numleft = current_position - actual_length;
+
+#ifdef DEBUG
+	  printf ("__mingw_fwrite: Seeking %ld bytes past end\n", numleft);
+#endif /* DEBUG */
+	  while (numleft > 0)
+	    {
+	      DWORD nzeros = (numleft > ZEROBLOCKSIZE)
+	                     ? ZEROBLOCKSIZE : numleft;
+	      DWORD written;
+	      if (! WriteFile ((HANDLE) _get_osfhandle (fileno (fp)),
+	                       __mingw_zeros, nzeros, &written, NULL))
+	        {
+		  /* Best we can hope for, or at least DJ says so. */
+	          SetFilePointer ((HANDLE) _get_osfhandle (fileno (fp)), 
+	                          0, 0, FILE_BEGIN);
+		  return -1;
+		}
+	      if (written < nzeros)
+	        {
+		  /* Likewise. */
+	          SetFilePointer ((HANDLE) _get_osfhandle (fileno (fp)), 
+	                          0, 0, FILE_BEGIN);
+		  return -1;
+		}
+
+	      numleft -= written;
+	    }
+	    FlushFileBuffers ((HANDLE) _get_osfhandle (fileno (fp)));
+	}
+    }
+  return fwrite (buffer, size, count, fp);
+}