feat: Convert DirectTransport to use ctypes

Author: kadler

setup.py

@@ -1,5 +1,4 @@
-from setuptools import setup, find_packages, Extension
-from platform import system
+from setuptools import setup, find_packages
 
 
 setup(
@@ -14,10 +13,6 @@
     zip_safe=False,
     packages=find_packages(where="src"),
     package_dir={"": "src"},
-    ext_modules=[
-        Extension('itoolkit/transport/_direct',
-                  ['src/itoolkit/transport/direct.c'])
-    ] if system() == 'OS400' else [],
     classifiers=[
         "License :: OSI Approved :: MIT License",
         "Programming Language :: Python :: 2.7",

src/itoolkit/transport/_direct.py

@@ -0,0 +1,206 @@
+import os
+
+from ctypes import c_int, c_uint, c_int16, c_ulonglong, c_void_p, c_char_p, \
+                   CDLL, DEFAULT_MODE, POINTER, Structure, addressof, sizeof, \
+                   create_string_buffer
+
+RTLD_MEMBER = 0x00040000
+
+
+class ILEPointer(Structure):
+    "An ILE pointer type"
+    _pack_ = 16
+    _fields_ = [
+        ("hi", c_ulonglong),
+        ("lo", c_ulonglong)
+    ]
+
+
+try:
+    _LIBC = CDLL("/QOpenSys/usr/lib/libc.a(shr_64.o)",
+                 DEFAULT_MODE | RTLD_MEMBER)
+
+    _SETSPP = _LIBC._SETSPP
+    _SETSPP.argtypes = [POINTER(ILEPointer), c_void_p]
+
+    _ILELOADX = _LIBC._ILELOADX
+    _ILELOADX.argtypes = [c_char_p, c_uint]
+    _ILELOADX.restype = c_ulonglong
+
+    _ILESYMX = _LIBC._ILESYMX
+    _ILESYMX.argtypes = [POINTER(ILEPointer), c_ulonglong, c_char_p]
+
+    _ILECALLX = _LIBC._ILECALLX
+    _ILECALLX.argtypes = [
+        POINTER(ILEPointer),
+        c_void_p,
+        POINTER(c_int16),
+        c_int16,
+        c_int
+    ]
+except OSError:
+    # Either we couldn't load libc or we couldn't find the necessary syscalls
+    # exported from libc. Either way, this platform is unsupported so we raise
+    # an import error to prevent it from being used.
+    raise ImportError
+
+ILELOAD_LIBOBJ = 0x00000001
+ILESYM_PROCEDURE = 1
+
+RESULT_VOID = 0
+RESULT_INT8 = -1
+RESULT_UINT8 = -2
+RESULT_INT16 = -3
+RESULT_UINT16 = -4
+RESULT_INT32 = -5
+RESULT_UINT32 = -6
+RESULT_INT64 = -7
+RESULT_UINT64 = -8
+RESULT_FLOAT64 = -10
+RESULT_FLOAT128 = -18
+
+ARG_END = 0
+ARG_MEMPTR = -11
+
+
+class MemPointer(ILEPointer):
+    "An ILE pointer type to be used with ARG_MEMPTR"
+    _pack_ = 16
+
+    def __init__(self, addr=0):
+        super(MemPointer, self).__int__()
+        self.hi = 0
+        self.lo = addr
+
+    @property
+    def addr(self):
+        return self.lo
+
+    @addr.setter
+    def addr(self, addr):
+        self.lo = addr
+
+
+class ILEArglistBase(Structure):
+    "ILECALL argument list base member"
+    _pack_ = 16
+    _fields_ = [
+        ('descriptor', ILEPointer),
+        ('result', ILEPointer),
+    ]
+
+
+class RunASCIIArglist(Structure):
+    "Argument list definition for the RUNASCII procedure"
+    _pack_ = 16
+    _fields_ = [
+        ('base', ILEArglistBase),
+        ('ipc', MemPointer),
+        ('ipc_len', MemPointer),
+        ('ctl', MemPointer),
+        ('ctl_len', MemPointer),
+        ('xmlin', MemPointer),
+        ('xmlin_len', MemPointer),
+        ('xmlout', MemPointer),
+        ('xmlout_len', MemPointer),
+        ('pase_ccsid', MemPointer),
+        ('ile_ccsid', MemPointer),
+    ]
+
+
+RunASCIISignature = c_int16 * 11
+
+_SIGNATURE = RunASCIISignature(
+        ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR,
+        ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR, ARG_MEMPTR,
+        ARG_END
+)
+
+
+class _XMLSERVICE:
+    def __init__(self, library):
+        self.library = library
+
+        path = "{library}/XMLSTOREDP".format(library=library)
+        actgrp = _ILELOADX(path.encode(), ILELOAD_LIBOBJ)
+        if actgrp == 0xffffffffffffffff:
+            raise OSError("{path} not found".format(path))
+
+        self._RUNASCII = ILEPointer()
+        if _ILESYMX(self._RUNASCII, actgrp, b"RUNASCII") != ILESYM_PROCEDURE:
+            raise OSError("RUNASCII procedure not found in {path}".format(path))
+
+    def __call__(self, xmlin, ipc, ctl):
+        ipc = c_char_p(ipc.encode())
+        ipc_len = c_int(len(ipc.value))
+
+        ctl = c_char_p(ctl.encode())
+        ctl_len = c_int(len(ctl.value))
+
+        xmlin = c_char_p(xmlin.encode())
+        xmlin_len = c_int(len(xmlin.value))
+
+        xmlout = create_string_buffer(0x1000000)  # 16MiB
+        xmlout_len = c_int(sizeof(xmlout))
+
+        pase_ccsid = c_int(1208)
+        ile_ccsid = c_int(0)
+
+        # RUNASCII doesn't just take ILE pointers, it takes ILE pointers to ILE
+        # pointers, so we first copy the PASE pointer in to a space pointer for
+        # each pointer parameter... *except* for the integer parameters, which
+        # are just pointers to integers for some reason...
+        ipc_spp = ILEPointer()
+        ctl_spp = ILEPointer()
+        xmlin_spp = ILEPointer()
+        xmlout_spp = ILEPointer()
+
+        _SETSPP(ipc_spp, ipc)
+        _SETSPP(ctl_spp, ctl)
+        _SETSPP(xmlin_spp, xmlin)
+        _SETSPP(xmlout_spp, xmlout)
+
+        arglist = RunASCIIArglist()
+        arglist.ipc.addr = addressof(ipc_spp)
+        arglist.ipc_len.addr = addressof(ipc_len)
+        arglist.ctl.addr = addressof(ctl_spp)
+        arglist.ctl_len.addr = addressof(ctl_len)
+        arglist.xmlin.addr = addressof(xmlin_spp)
+        arglist.xmlin_len.addr = addressof(xmlin_len)
+        arglist.xmlout.addr = addressof(xmlout_spp)
+        arglist.xmlout_len.addr = addressof(xmlout_len)
+        arglist.pase_ccsid.addr = addressof(pase_ccsid)
+        arglist.ile_ccsid.addr = addressof(ile_ccsid)
+
+        if _ILECALLX(self._RUNASCII, addressof(arglist), _SIGNATURE,
+                     RESULT_INT32, 0):
+            raise RuntimeError("Failed to call XMLSERVICE with _ILECALL")
+
+        if arglist.base.result.lo & 0xffffffff:
+            raise RuntimeError("XMLSERVICE returned an error")
+
+        return xmlout.value
+
+
+def xmlservice(xmlin, ipc, ctl):
+    # If we haven't yet initialized XMLSERVICE, do that now
+    if not hasattr(xmlservice, 'cached_obj'):
+
+        libraries = [os.getenv("XMLSERVICE"), "QXMLSERV", "XMLSERVICE"]
+
+        found = False
+        for library in libraries:
+            if not library:
+                continue
+
+            try:
+                xmlservice.cached_obj = _XMLSERVICE(library)
+                found = True
+            except OSError:
+                continue
+
+        if not found:
+            # TODO: Message string
+            raise OSError("Couldn't load RUNASCII function from XMLSERVICE")
+
+    return xmlservice.cached_obj(xmlin, ipc, ctl)