1 files changed, 77 insertions, 5 deletions

diff --git a/winsup/cygwin/mount.cc b/winsup/cygwin/mount.cc
index eecd72692..43f462686 100644
--- a/winsup/cygwin/mount.cc
+++ b/winsup/cygwin/mount.cc
@@ -1177,9 +1177,10 @@ mount_info::from_fstab (bool user, WCHAR fstab[], PWCHAR fstab_end)
 {
   UNICODE_STRING upath;
   OBJECT_ATTRIBUTES attr;
-  NT_readline rl;
+  IO_STATUS_BLOCK io;
+  NTSTATUS status;
+  HANDLE fh;
   tmp_pathbuf tp;
-  char *buf = tp.c_get ();
 
   if (user)
     {
@@ -1194,10 +1195,81 @@ 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);
-  if (rl.init (&attr, buf, NT_MAX_PATH))
-    while ((buf = rl.gets ()))
-      if (!from_fstab_line (buf, user))
+  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))
+    {
+      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;
 }