* miscfuncs.h (class NT_readline): New class to implement line-wise

reading from file using native NT functions.
	* miscfuncs.cc (NT_readline::init): New method.
	* mount.cc (mount_info::from_fstab): Utilize NT_readline to read
	fstab files.

winsup/cygwin/ChangeLog

@@ -1,3 +1,11 @@
+2014-02-08  Corinna Vinschen  <corinna@vinschen.de>
+
+	* miscfuncs.h (class NT_readline): New class to implement line-wise
+	reading from file using native NT functions.
+	* miscfuncs.cc (NT_readline::init): New method.
+	* mount.cc (mount_info::from_fstab): Utilize NT_readline to read
+	fstab files.
+
 2014-02-06  Corinna Vinschen  <corinna@vinschen.de>
 
 	* fhandler_disk_file.cc (fhandler_disk_file::fchown): Fix typo in

winsup/cygwin/miscfuncs.cc

@@ -1,7 +1,7 @@
 /* miscfuncs.cc: misc funcs that don't belong anywhere else
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
-   2007, 2008, 2009, 2010, 2011, 2012, 2013 Red Hat, Inc.
+   2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -384,6 +384,82 @@ WritePipeOverlapped (HANDLE h, LPCVOID buf, DWORD len, LPDWORD ret_len,
   return ret;
 }
 
+bool
+NT_readline::init (POBJECT_ATTRIBUTES attr, PCHAR in_buf, ULONG in_buflen)
+{
+  NTSTATUS status;
+  IO_STATUS_BLOCK io;
+
+  status = NtOpenFile (&fh, SYNCHRONIZE | FILE_READ_DATA, attr, &io,
+                       FILE_SHARE_VALID_FLAGS,
+                       FILE_SYNCHRONOUS_IO_NONALERT
+                       | FILE_OPEN_FOR_BACKUP_INTENT);
+  if (!NT_SUCCESS (status))
+    {
+      paranoid_printf ("NtOpenFile(%S) failed, status %y",
+		       &attr->ObjectName, status);
+      return false;
+    }
+  buf = in_buf;
+  buflen = in_buflen;
+  got = end = buf;
+  len = 0;
+  line = 1;
+  return true;
+}
+
+PCHAR 
+NT_readline::gets ()
+{
+  IO_STATUS_BLOCK io;
+
+  while (true)
+    {
+      /* len == 0 indicates we have to read from the file. */
+      if (!len)
+	{
+	  if (!NT_SUCCESS (NtReadFile (fh, NULL, NULL, NULL, &io, got,
+				       (buflen - 2) - (got - buf), NULL, NULL)))
+	    return NULL;
+	  len = io.Information;
+	  /* Set end marker. */
+	  got[len] = got[len + 1] = '\0';
+	  /* Set len to the absolute len of bytes in buf. */
+	  len += got - buf;
+	  /* Reset got to start reading at the start of the buffer again. */
+	  got = end = buf;
+	}
+      else
+	{
+	  got = end + 1;
+	  ++line;
+	}
+      /* Still some valid full line? */
+      if (got < buf + len)
+	{
+	  if ((end = strchr (got, '\n')))
+	    {
+	      end[end[-1] == '\r' ? -1 : 0] = '\0';
+	      return got;
+	    }
+	  /* Last line missing a \n at EOF? */
+	  if (len < buflen - 2)
+	    {
+	      len = 0;
+	      return got;
+	    }
+	}
+      /* We have to read once more.  Move remaining bytes to the start of
+         the buffer and reposition got so that it points to the end of
+         the remaining bytes. */
+      len = buf + len - got;
+      memmove (buf, got, len);
+      got = buf + len;
+      buf[len] = buf[len + 1] = '\0';
+      len = 0;
+    }
+}
+
 /* backslashify: Convert all forward slashes in src path to back slashes
    in dst path.  Add a trailing slash to dst when trailing_slash_p arg
    is set to 1. */

winsup/cygwin/miscfuncs.h

@@ -1,7 +1,7 @@
 /* miscfuncs.h: main Cygwin header file.
 
    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
-   2007, 2008, 2009, 2010, 2011, 2012, 2013 Red Hat, Inc.
+   2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014 Red Hat, Inc.
 
 This file is part of Cygwin.
 
@@ -23,6 +23,24 @@ BOOL WINAPI ReadPipeOverlapped (HANDLE h, PVOID buf, DWORD len,
 BOOL WINAPI WritePipeOverlapped (HANDLE h, LPCVOID buf, DWORD len,
 				 LPDWORD ret_len, DWORD timeout);
 
+/* class for per-line reading using native functions.  The caller provides
+   the file as an POBJECT_ATTRIBUTES, and the buffer space. */
+class NT_readline
+{
+  HANDLE fh;
+  PCHAR buf;
+  PCHAR got;
+  PCHAR end;
+  ULONG buflen;
+  ULONG len;
+  ULONG line;
+public:
+  NT_readline () : fh (NULL) {}
+  bool init (POBJECT_ATTRIBUTES attr, char *buf, ULONG buflen);
+  PCHAR gets ();
+  ~NT_readline () { if (fh) NtClose (fh); }
+};
+
 extern "C" void yield ();
 
 #define import_address(x) __import_address ((void *)(x))

winsup/cygwin/mount.cc

@@ -1177,10 +1177,9 @@ mount_info::from_fstab (bool user, WCHAR fstab[], PWCHAR fstab_end)
 {
   UNICODE_STRING upath;
   OBJECT_ATTRIBUTES attr;
-  IO_STATUS_BLOCK io;
+  NT_readline rl;
-  NTSTATUS status;
-  HANDLE fh;
   tmp_pathbuf tp;
+  char *buf = tp.c_get ();
 
   if (user)
     {
@@ -1195,81 +1194,10 @@ mount_info::from_fstab (bool user, WCHAR fstab[], PWCHAR fstab_end)
   RtlInitUnicodeString (&upath, fstab);
   InitializeObjectAttributes (&attr, &upath, OBJ_CASE_INSENSITIVE, NULL, NULL);
   debug_printf ("Try to read mounts from %W", fstab);
-  status = NtOpenFile (&fh, SYNCHRONIZE | FILE_READ_DATA, &attr, &io,
+  if (rl.init (&attr, buf, NT_MAX_PATH))
-		       FILE_SHARE_VALID_FLAGS,
+    while ((buf = rl.gets ()))
-		       FILE_SYNCHRONOUS_IO_NONALERT
+      if (!from_fstab_line (buf, user))
-		       | FILE_OPEN_FOR_BACKUP_INTENT);
-  if (!NT_SUCCESS (status))
-    {
-      debug_printf ("NtOpenFile(%S) failed, %y", &upath, status);
-      return false;
-    }
-
-  char *buf = tp.c_get ();
-  char *got = buf;
-  DWORD len = 0;
-  unsigned line = 1;
-  /* Using buffer size - 2 leaves space to append two \0. */
-  while (NT_SUCCESS (NtReadFile (fh, NULL, NULL, NULL, &io, got,
-				 (NT_MAX_PATH - 2) - (got - buf), NULL, NULL)))
-    {
-      char *end;
-
-      len = io.Information;
-      /* Set end marker. */
-      got[len] = got[len + 1] = '\0';
-      /* Set len to the absolute len of bytes in buf. */
-      len += got - buf;
-      /* Reset got to start reading at the start of the buffer again. */
-      got = buf;
-retry:
-      bool got_nl = false;
-      while (got < buf + len && (end = strchr (got, '\n')))
-	{
-	  got_nl = true;
-	  end[end[-1] == '\r' ? -1 : 0] = '\0';
-	  if (!from_fstab_line (got, user))
-	    goto done;
-	  got = end + 1;
-	  ++line;
-	}
-      if (len < (NT_MAX_PATH - 2))
 	break;
-      /* Check if the buffer contained at least one \n.  If not, the
-	 line length is > 32K.  We don't take such long lines.  Print
-	 a debug message and skip this line entirely. */
-      if (!got_nl)
-	{
-	  system_printf ("%W: Line %d too long, skipping...", fstab, line);
-	  while (NT_SUCCESS (NtReadFile (fh, NULL, NULL, NULL, &io, buf,
-					 (NT_MAX_PATH - 2), NULL, NULL)))
-	    {
-	      len = io.Information;
-	      buf[len] = buf[len + 1] = '\0';
-	      got = strchr (buf, '\n');
-	      if (got)
-		{
-		  ++got;
-		  ++line;
-		  goto retry;
-		}
-	    }
-	  got = buf;
-	  break;
-	}
-      /* We have to read once more.  Move remaining bytes to the start of
-	 the buffer and reposition got so that it points to the end of
-	 the remaining bytes. */
-      len = buf + len - got;
-      memmove (buf, got, len);
-      got = buf + len;
-      buf[len] = buf[len + 1] = '\0';
-    }
-  /* Catch a last line without trailing \n. */
-  if (got > buf)
-    from_fstab_line (got, user);
-done:
-  NtClose (fh);
   return true;
 }