saip-tool: Add 'extract-apps' to dump all applications from eSIM profile

This new action can be used to dump all java applications as either raw
IJC file or converted to CAP format (the usual format generated by
JavaCard toolchains).

Change-Id: I51cffa5ba3ddbea491341d678ec9249d7cf470a5
---
M contrib/saip-tool.py
M pySim/esim/saip/__init__.py
A pySim/javacard.py
3 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/contrib/saip-tool.py b/contrib/saip-tool.py
index 68072fa..6f2a2a4 100755
--- a/contrib/saip-tool.py
+++ b/contrib/saip-tool.py
@@ -19,11 +19,13 @@
 import sys
 import argparse
 import logging
+import zipfile
 from pathlib import Path
 from typing import List
 
 from pySim.esim.saip import *
 from pySim.esim.saip.validation import CheckBasicStructure
+from pySim import javacard
 from pySim.utils import h2b, b2h, swap_nibbles
 from pySim.pprint import HexBytesPrettyPrinter
 
@@ -56,6 +58,10 @@
 
 parser_info = subparsers.add_parser('info', help='Display information about the profile')
 
+parser_eapp = subparsers.add_parser('extract-apps', help='Extract applications as loadblock file')
+parser_eapp.add_argument('--output-dir', default='.', help='Output directory (where to store files)')
+parser_eapp.add_argument('--format', default='cap', choices=['ijc', 'cap'], help='Data format of output files')
+
 def do_split(pes: ProfileElementSequence, opts):
     i = 0
     for pe in pes.pe_list:
@@ -176,6 +182,21 @@
             print("\tInstance AID: %s" % b2h(inst['instanceAID']))
     pass
 
+def do_extract_apps(pes:ProfileElementSequence, opts):
+    apps = pes.pe_by_type.get('application', [])
+    for app_pe in apps:
+        package_aid = b2h(app_pe.decoded['loadBlock']['loadPackageAID'])
+
+        fname = os.path.join(opts.output_dir, '%s-%s.%s' % (pes.iccid, package_aid, opts.format))
+        load_block_obj = app_pe.decoded['loadBlock']['loadBlockObject']
+        print("Writing Load Package AID: %s to file %s" % (package_aid, fname))
+        if opts.format == 'ijc':
+            with open(fname, 'wb') as f:
+                f.write(load_block_obj)
+        else:
+            with io.BytesIO(load_block_obj) as f, zipfile.ZipFile(fname, 'w') as z:
+                javacard.ijc_to_cap(f, z, package_aid)
+
 
 if __name__ == '__main__':
     opts = parser.parse_args()
@@ -197,3 +218,5 @@
         do_remove_naa(pes, opts)
     elif opts.command == 'info':
         do_info(pes, opts)
+    elif opts.command == 'extract-apps':
+        do_extract_apps(pes, opts)
diff --git a/pySim/esim/saip/__init__.py b/pySim/esim/saip/__init__.py
index 278b5cf..e690e6c 100644
--- a/pySim/esim/saip/__init__.py
+++ b/pySim/esim/saip/__init__.py
@@ -617,7 +617,19 @@
         # TODO: remove any records related to the ADFs from EF.DIR
 
     def __repr__(self) -> str:
-        return "PESequence(%s)" % ', '.join([str(x) for x in self.pe_list])
+        return "PESequence(%s: %s)" % (self.iccid, ', '.join([str(x) for x in self.pe_list]))
 
     def __iter__(self) -> str:
         yield from self.pe_list
+
+    @property
+    def iccid(self) -> Optional[str]:
+        """The ICCID of the profile."""
+        if not 'header' in self.pe_by_type:
+            return None
+        if len(self.pe_by_type['header']) < 1:
+            return None
+        pe_hdr_dec = self.pe_by_type['header'][0].decoded
+        if not 'iccid' in pe_hdr_dec:
+            return None
+        return b2h(pe_hdr_dec['iccid'])
diff --git a/pySim/javacard.py b/pySim/javacard.py
new file mode 100644
index 0000000..46f6ec0
--- /dev/null
+++ b/pySim/javacard.py
@@ -0,0 +1,19 @@
+# JavaCard related utilities
+
+import zipfile
+import struct
+import sys
+import io
+
+def ijc_to_cap(in_file: io.IOBase, out_zip: zipfile.ZipFile, p : str = "foo"):
+    """Convert an ICJ (Interoperable Java Card) file [back] to a CAP file."""
+    TAGS = ["Header", "Directory", "Applet", "Import", "ConstantPool", "Class", "Method", "StaticField", "RefLocation", "Export", "Descriptor", "Debug"]
+    b = in_file.read()
+    while len(b):
+        tag, size = struct.unpack('!BH', b[0:3])
+        out_zip.writestr(p+"/javacard/"+TAGS[tag-1]+".cap", b[0:3+size])
+        b = b[3+size:]
+
+# example usage:
+# with io.open(sys.argv[1],"rb") as f, zipfile.ZipFile(sys.argv[2], "wb") as z:
+#     ijc_to_cap(f, z)

