LibreOffice Module bridges (master)  1
gcc3_ios/except.cxx
Go to the documentation of this file.
1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 /*
3  * This file is part of the LibreOffice project.
4  *
5  * This Source Code Form is subject to the terms of the Mozilla Public
6  * License, v. 2.0. If a copy of the MPL was not distributed with this
7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8  *
9  * This file incorporates work covered by the following license notice:
10  *
11  * Licensed to the Apache Software Foundation (ASF) under one or more
12  * contributor license agreements. See the NOTICE file distributed
13  * with this work for additional information regarding copyright
14  * ownership. The ASF licenses this file to you under the Apache
15  * License, Version 2.0 (the "License"); you may not use this file
16  * except in compliance with the License. You may obtain a copy of
17  * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18  */
19 
20 #include "sal/config.h"
21 
22 #include <cassert>
23 #include <new>
24 #include <stdio.h>
25 #include <string.h>
26 #include <typeinfo>
27 
28 #include <cxxabi.h>
29 #include <dlfcn.h>
30 
31 #include "com/sun/star/uno/RuntimeException.hpp"
32 #include "com/sun/star/uno/genfunc.hxx"
33 #include <sal/log.hxx>
34 #include "osl/mutex.hxx"
35 #include "rtl/strbuf.hxx"
36 #include "rtl/ustrbuf.hxx"
37 #include "typelib/typedescription.h"
38 #include "uno/any2.h"
39 #include <unordered_map>
40 #include "share.hxx"
41 
42 using namespace ::osl;
43 using namespace ::com::sun::star::uno;
44 
45 namespace CPPU_CURRENT_NAMESPACE {
46 
47 namespace {
48 
49 struct Fake_type_info {
50  virtual ~Fake_type_info() = delete;
51  char const * name;
52 };
53 
54 struct Fake_class_type_info: Fake_type_info {
55  virtual ~Fake_class_type_info() override = delete;
56 };
57 
58 struct Fake_si_class_type_info: Fake_class_type_info {
59  virtual ~Fake_si_class_type_info() override = delete;
60  void const * base;
61 };
62 
63 struct Base {};
64 struct Derived: Base {};
65 
66 std::type_info * createFake_class_type_info(char const * name) {
67  char * buf = new char[sizeof (Fake_class_type_info)];
68 
69  *reinterpret_cast<void **>(buf) = *reinterpret_cast<void * const *>(
70  &typeid(Base));
71  // copy __cxxabiv1::__class_type_info vtable into place
72  Fake_class_type_info * fake = reinterpret_cast<Fake_class_type_info *>(buf);
73  fake->name = name;
74  return reinterpret_cast<std::type_info *>(
75  static_cast<Fake_type_info *>(fake));
76 }
77 
78 std::type_info * createFake_si_class_type_info(
79  char const * name, std::type_info const * base)
80 {
81  char * buf = new char[sizeof (Fake_si_class_type_info)];
82 
83  *reinterpret_cast<void **>(buf) = *reinterpret_cast<void * const *>(
84  &typeid(Derived));
85  // copy __cxxabiv1::__si_class_type_info vtable into place
86  Fake_si_class_type_info * fake
87  = reinterpret_cast<Fake_si_class_type_info *>(buf);
88  fake->name = name;
89  fake->base = base;
90  return reinterpret_cast<std::type_info *>(
91  static_cast<Fake_type_info *>(fake));
92 }
93 
94 }
95 
96 #ifdef __GNUC__
97 #pragma GCC diagnostic push
98 #pragma GCC diagnostic ignored "-Wunused-function"
99 #endif
100 void dummy_can_throw_anything( char const * )
101 {
102 }
103 #ifdef __GNUC__
104 #pragma GCC diagnostic pop
105 #endif
106 
107 static OUString toUNOname( char const * p )
108 {
109 #if OSL_DEBUG_LEVEL > 1
110  char const * start = p;
111 #endif
112 
113  // example: N3com3sun4star4lang24IllegalArgumentExceptionE
114 
115  OUStringBuffer buf( 64 );
116  assert( 'N' == *p );
117  ++p; // skip N
118 
119  while ('E' != *p)
120  {
121  // read chars count
122  long n = (*p++ - '0');
123  while ('0' <= *p && '9' >= *p)
124  {
125  n *= 10;
126  n += (*p++ - '0');
127  }
128  buf.appendAscii( p, n );
129  p += n;
130  if ('E' != *p)
131  buf.append( '.' );
132  }
133 
134 #if OSL_DEBUG_LEVEL > 1
135  OUString ret( buf.makeStringAndClear() );
136  OString c_ret( OUStringToOString( ret, RTL_TEXTENCODING_ASCII_US ) );
137  fprintf( stderr, "> toUNOname(): %s => %s\n", start, c_ret.getStr() );
138  return ret;
139 #else
140  return buf.makeStringAndClear();
141 #endif
142 }
143 
144 class RTTI
145 {
146  typedef std::unordered_map< OUString, std::type_info *, OUStringHash > t_rtti_map;
147 
148  Mutex m_mutex;
149  t_rtti_map m_rttis;
150  t_rtti_map m_generatedRttis;
151 
152  void * m_hApp;
153 
154 public:
155  RTTI();
156  ~RTTI();
157 
158  std::type_info * getRTTI( typelib_CompoundTypeDescription * );
159 };
160 
161 RTTI::RTTI()
162  : m_hApp( dlopen( nullptr, RTLD_LAZY ) )
163 {
164 }
165 
166 RTTI::~RTTI()
167 {
168  dlclose( m_hApp );
169 }
170 
171 
172 std::type_info * RTTI::getRTTI( typelib_CompoundTypeDescription *pTypeDescr )
173 {
174  std::type_info * rtti;
175 
176  OUString const & unoName = OUString::unacquired(&pTypeDescr->aBase.pTypeName);
177 
178  MutexGuard guard( m_mutex );
179  t_rtti_map::const_iterator iFind( m_rttis.find( unoName ) );
180  if (iFind == m_rttis.end())
181  {
182  // RTTI symbol
183  OStringBuffer buf( 64 );
184  buf.append( "_ZTIN" );
185  sal_Int32 index = 0;
186  do
187  {
188  OUString token( unoName.getToken( 0, '.', index ) );
189  buf.append( token.getLength() );
190  OString c_token( OUStringToOString( token, RTL_TEXTENCODING_ASCII_US ) );
191  buf.append( c_token );
192  }
193  while (index >= 0);
194  buf.append( 'E' );
195 
196  OString symName( buf.makeStringAndClear() );
197  rtti = static_cast<std::type_info *>(dlsym( m_hApp, symName.getStr() ));
198 
199  if (rtti)
200  {
201  std::pair< t_rtti_map::iterator, bool > insertion(
202  m_rttis.insert( t_rtti_map::value_type( unoName, rtti ) ) );
203  SAL_WARN_IF( !insertion.second,
204  "bridges",
205  "inserting new rtti failed" );
206  }
207  else
208  {
209  // try to lookup the symbol in the generated rtti map
210  t_rtti_map::const_iterator iFind2( m_generatedRttis.find( unoName ) );
211  if (iFind2 == m_generatedRttis.end())
212  {
213  // we must generate it !
214  // symbol and rtti-name is nearly identical,
215  // the symbol is prefixed with _ZTI
216  char * rttiName = strdup(symName.getStr() + 4);
217  if (rttiName == nullptr) {
218  throw std::bad_alloc();
219  }
220 #if OSL_DEBUG_LEVEL > 1
221  fprintf( stderr,"generated rtti for %s\n", rttiName );
222 #endif
223  if (pTypeDescr->pBaseTypeDescription)
224  {
225  // ensure availability of base
226  std::type_info * base_rtti = getRTTI(
227  pTypeDescr->pBaseTypeDescription );
228  rtti = createFake_si_class_type_info(rttiName, base_rtti);
229  }
230  else
231  {
232  rtti = createFake_class_type_info(rttiName);
233  }
234 
235  std::pair< t_rtti_map::iterator, bool > insertion(
236  m_generatedRttis.insert( t_rtti_map::value_type( unoName, rtti ) ) );
237  SAL_WARN_IF( !insertion.second,
238  "bridges",
239  "inserting new generated rtti failed" );
240  }
241  else // taking already generated rtti
242  {
243  rtti = iFind2->second;
244  }
245  }
246  }
247  else
248  {
249  rtti = iFind->second;
250  }
251 
252  return rtti;
253 }
254 
255 
256 static void deleteException( void * pExc )
257 {
258  __cxa_exception const * header = static_cast<__cxa_exception const *>(pExc) - 1;
259  // The libcxxabi commit
260  // <http://llvm.org/viewvc/llvm-project?view=revision&revision=303175>
261  // "[libcxxabi] Align unwindHeader on a double-word boundary" towards
262  // LLVM 5.0 changed the size of __cxa_exception by adding
263  //
264  // __attribute__((aligned))
265  //
266  // to the final member unwindHeader, on x86-64 effectively adding a hole of
267  // size 8 in front of that member (changing its offset from 88 to 96,
268  // sizeof(__cxa_exception) from 120 to 128, and alignof(__cxa_exception)
269  // from 8 to 16); a hack to dynamically determine whether we run against a
270  // LLVM 5 libcxxabi is to look at the exceptionDestructor member, which must
271  // point to this function (the use of __cxa_exception in fillUnoException is
272  // unaffected, as it only accesses members towards the start of the struct,
273  // through a pointer known to actually point at the start). The libcxxabi commit
274  // <https://github.com/llvm/llvm-project/commit/9ef1daa46edb80c47d0486148c0afc4e0d83ddcf>
275  // "Insert padding before the __cxa_exception header to ensure the thrown" in LLVM 6
276  // removes the need for this hack, so it can be removed again once we can be sure that we only
277  // run against libcxxabi from LLVM >= 6:
278  if (header->exceptionDestructor != &deleteException) {
279  header = reinterpret_cast<__cxa_exception const *>(
280  reinterpret_cast<char const *>(header) - 8);
281  assert(header->exceptionDestructor == &deleteException);
282  }
283  typelib_TypeDescription * pTD = nullptr;
284  OUString unoName( toUNOname( header->exceptionType->name() ) );
285  ::typelib_typedescription_getByName( &pTD, unoName.pData );
286  assert(pTD && "### unknown exception type! leaving out destruction => leaking!!!");
287  if (pTD)
288  {
289  ::uno_destructData( pExc, pTD, cpp_release );
290  ::typelib_typedescription_release( pTD );
291  }
292 }
293 
294 void raiseException( uno_Any * pUnoExc, uno_Mapping * pUno2Cpp )
295 {
296 #if OSL_DEBUG_LEVEL > 1
297  OString cstr(
299  OUString::unacquired( &pUnoExc->pType->pTypeName ),
300  RTL_TEXTENCODING_ASCII_US ) );
301  fprintf( stderr, "> uno exception occurred: %s\n", cstr.getStr() );
302 #endif
303  void * pCppExc;
304  std::type_info * rtti;
305 
306  {
307  // construct cpp exception object
308  typelib_TypeDescription * pTypeDescr = nullptr;
309  TYPELIB_DANGER_GET( &pTypeDescr, pUnoExc->pType );
310  assert(pTypeDescr);
311  if (! pTypeDescr)
312  {
313  throw RuntimeException(
314  "cannot get typedescription for type " +
315  OUString::unacquired( &pUnoExc->pType->pTypeName ) );
316  }
317 
318  pCppExc = __cxxabiv1::__cxa_allocate_exception( pTypeDescr->nSize );
319  ::uno_copyAndConvertData( pCppExc, pUnoExc->pData, pTypeDescr, pUno2Cpp );
320 
321  // destruct uno exception
322  ::uno_any_destruct( pUnoExc, nullptr );
323  // avoiding locked counts
324  static RTTI rtti_data;
325  rtti = rtti_data.getRTTI(reinterpret_cast<typelib_CompoundTypeDescription*>(pTypeDescr));
326  TYPELIB_DANGER_RELEASE( pTypeDescr );
327  assert(rtti && "### no rtti for throwing exception!");
328  if (! rtti)
329  {
330  throw RuntimeException(
331  "no rtti for type " +
332  OUString::unacquired( &pUnoExc->pType->pTypeName ) );
333  }
334  }
335 
336  // void __cxa_throw(void* thrown_exception,
337  // struct std::type_info * tinfo,
338  // void (*dest)(void*));
339  __cxxabiv1::__cxa_throw( pCppExc, rtti, deleteException );
340 }
341 
342 void fillUnoException(uno_Any * pUnoExc, uno_Mapping * pCpp2Uno)
343 {
345  if (! header)
346  {
347  RuntimeException aRE( "no exception header!" );
348  Type const & rType = cppu::UnoType<decltype(aRE)>::get();
349  uno_type_any_constructAndConvert( pUnoExc, &aRE, rType.getTypeLibType(), pCpp2Uno );
350  SAL_WARN("bridges", aRE.Message);
351  return;
352  }
353 
354  // Very bad HACK to find out whether we run against a libcxxabi that has a new
355  // __cxa_exception::reserved member at the start, introduced with LLVM 10
356  // <https://github.com/llvm/llvm-project/commit/674ec1eb16678b8addc02a4b0534ab383d22fa77>
357  // "[libcxxabi] Insert padding in __cxa_exception struct for compatibility". The layout of the
358  // start of __cxa_exception is
359  //
360  // [8 byte void *reserve]
361  // 8 byte size_t referenceCount
362  //
363  // where the (bad, hacky) assumption is that reserve (if present) is null
364  // (__cxa_allocate_exception in at least LLVM 11 zero-fills the object, and nothing actively
365  // sets reserve) while referenceCount is non-null (__cxa_throw sets it to 1, and
366  // __cxa_decrement_exception_refcount destroys the exception as soon as it drops to 0; for a
367  // __cxa_dependent_exception, the referenceCount member is rather
368  //
369  // 8 byte void* primaryException
370  //
371  // but which also will always be set to a non-null value in __cxa_rethrow_primary_exception).
372  // As described in the definition of __cxa_exception
373  // (bridges/source/cpp_uno/gcc3_macosx_x86-64/share.hxx), this hack (together with the "#if 0"
374  // there) can be dropped once we can be sure that we only run against new libcxxabi that has the
375  // reserve member:
376  if (*reinterpret_cast<void **>(header) == nullptr) {
377  header = reinterpret_cast<__cxa_exception *>(reinterpret_cast<void **>(header) + 1);
378  }
379 
380  std::type_info *exceptionType = __cxxabiv1::__cxa_current_exception_type();
381 
382  typelib_TypeDescription * pExcTypeDescr = nullptr;
383  OUString unoName( toUNOname( exceptionType->name() ) );
384 #if OSL_DEBUG_LEVEL > 1
385  OString cstr_unoName( OUStringToOString( unoName, RTL_TEXTENCODING_ASCII_US ) );
386  fprintf( stderr, "> c++ exception occurred: %s\n", cstr_unoName.getStr() );
387 #endif
388  typelib_typedescription_getByName( &pExcTypeDescr, unoName.pData );
389  if (nullptr == pExcTypeDescr)
390  {
391  RuntimeException aRE( "exception type not found: " + unoName );
392  Type const & rType = cppu::UnoType<decltype(aRE)>::get();
393  uno_type_any_constructAndConvert( pUnoExc, &aRE, rType.getTypeLibType(), pCpp2Uno );
394  SAL_WARN("bridges", aRE.Message);
395  }
396  else
397  {
398  // construct uno exception any
399  uno_any_constructAndConvert( pUnoExc, header->adjustedPtr, pExcTypeDescr, pCpp2Uno );
400  typelib_typedescription_release( pExcTypeDescr );
401  }
402 }
403 
404 }
405 
406 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
Type
static void deleteException(void *pExc)
static OUString toUNOname(char const *p)
struct _uno_Mapping uno_Mapping
Definition: msvc/except.hxx:32
void fillUnoException(uno_Any *pExc, uno_Mapping *pCpp2Uno)
sal_Int64 n
std::type_info * __cxa_current_exception_type()
void SAL_CALL uno_type_any_constructAndConvert(uno_Any *pDest, void *pSource, typelib_TypeDescriptionReference *pType, uno_Mapping *mapping) SAL_THROW_EXTERN_C()
void * m_hApp
void SAL_CALL uno_any_constructAndConvert(uno_Any *pDest, void *pSource, typelib_TypeDescription *pTypeDescr, uno_Mapping *mapping) SAL_THROW_EXTERN_C()
const sal_Int8 header[]
OString OUStringToOString(std::u16string_view str, ConnectionSettings const *settings)
struct _uno_Any uno_Any
Definition: msvc/except.hxx:31
Base
type_info * getRTTI(typelib_CompoundTypeDescription *)
void const * base
tuple index
struct _typelib_TypeDescription typelib_TypeDescription
Definition: msvc/except.hxx:52
void SAL_CALL typelib_typedescription_release(typelib_TypeDescription *pTD) SAL_THROW_EXTERN_C()
std::unordered_map< OUString, std::type_info *, OUStringHash > t_rtti_map
void SAL_CALL typelib_typedescription_getByName(typelib_TypeDescription **ppRet, rtl_uString *pName) SAL_THROW_EXTERN_C()
void * __cxa_allocate_exception(size_t thrown_size)
void raiseException(uno_Any *pUnoExc, uno_Mapping *pUno2Cpp)
__cxa_eh_globals * __cxa_get_globals()
#define SAL_WARN_IF(condition, area, stream)
void * p
#define SAL_WARN(area, stream)
void dummy_can_throw_anything(char const *)
void __cxa_throw(void *thrown_exception, std::type_info *tinfo, void(*dest)(void *)) __attribute__((noreturn))
char const * name