1 files changed, 64 insertions, 0 deletions
diff --git a/xnloader.py b/xnloader.py
new file mode 100644
index 0000000..e194da4
--- /dev/null
+++ b/xnloader.py
@@ -0,0 +1,64 @@
+# NetWare-specific operations
+#
+# Copyright (c) 2013 Suse Linux Products.
+# Author: Charles Arnold <carnold@suse.com>
+#
+# This software may be freely redistributed under the terms of the GNU
+# general public license.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# 51 Franklin St, Boston, MA 02110
+
+# Binary patching of xnloader.sys
+# For launching NetWare on Xen 4.2 and newer
+
+
+import os, sys, base64
+
+CODE_OFFSET=0x49F5
+NUMBER_OF_CODE_BYTES=17
+ORIGINAL_CODE="BA00080000C786FC1F0000FFFFFFFF31C9"
+PATCHED_CODE="BAF8070000834C961CFFB9080000009090"
+XNLOADER_SYS_MD5SUM="eb76cce2a2d45928ea2bf26e01430af2"
+
+def patch_netware_loader(loader):
+    """Open the given xnloader.sys file and patch the relevant code hunk."""
+
+    # domUloader calls this with all kernels so perhaps this is not the NetWare loader
+    md5sum_cmd = 'md5sum ' + loader
+    p = os.popen(md5sum_cmd)
+    sum = p.read().split()[0]
+    p.close()
+    if sum != XNLOADER_SYS_MD5SUM:
+        return
+
+    try:
+        fd = os.open(loader, os.O_RDWR)
+    except Exception as e:
+        print(e, file=sys.stderr)
+        raise
+
+    # Validate minimum size for I/O
+    stat = os.fstat(fd)
+    if stat.st_size < CODE_OFFSET+NUMBER_OF_CODE_BYTES:
+        os.close(fd)
+        return
+
+    # Seek to location of code hunk
+    os.lseek(fd, CODE_OFFSET, os.SEEK_SET)
+
+    # Read code bytes at offset
+    buf = os.read(fd, NUMBER_OF_CODE_BYTES)
+
+    code_as_hex = base64.b16encode(buf)
+    code_as_hex = code_as_hex.decode('utf-8')
+    if code_as_hex == ORIGINAL_CODE:
+        # Seek back to start location of the code hunk
+        os.lseek(fd, CODE_OFFSET, os.SEEK_SET)
+        # Convert the PATCHED_CODE string to raw binary
+        code_as_bin = base64.b16decode(PATCHED_CODE)
+        # Write the patched code
+        os.write(fd, code_as_bin)
+    os.close(fd)
+