87 lines
2.7 KiB
C++
87 lines
2.7 KiB
C++
/*
|
|
* SignalSafeUnwind.cpp
|
|
*
|
|
* This source file is part of the FoundationDB open source project
|
|
*
|
|
* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
|
|
*
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
#include "SignalSafeUnwind.h"
|
|
|
|
int64_t dl_iterate_phdr_calls = 0;
|
|
|
|
#ifdef __linux__
|
|
|
|
#include <link.h>
|
|
|
|
static bool phdr_cache_initialized = false;
|
|
static std::vector< std::vector<uint8_t> > phdr_cache;
|
|
|
|
static int (*chain_dl_iterate_phdr)(
|
|
int (*callback) (struct dl_phdr_info *info,
|
|
size_t size, void *data),
|
|
void *data) = 0;
|
|
|
|
static int phdr_cache_add( struct dl_phdr_info *info, size_t size, void *data ) {
|
|
phdr_cache.push_back( std::vector<uint8_t>((uint8_t*)info, (uint8_t*)info + size) );
|
|
return 0;
|
|
}
|
|
|
|
static void initChain() {
|
|
// Ensure that chain_dl_iterate_phdr points to the "real" function that we are overriding
|
|
*(void**)&chain_dl_iterate_phdr = dlsym(RTLD_NEXT, "dl_iterate_phdr");
|
|
if (!chain_dl_iterate_phdr)
|
|
criticalError(FDB_EXIT_ERROR, "SignalSafeUnwindError", "Unable to find dl_iterate_phdr symbol");
|
|
}
|
|
|
|
void initSignalSafeUnwind() {
|
|
initChain();
|
|
|
|
phdr_cache.clear();
|
|
if (chain_dl_iterate_phdr(&phdr_cache_add, 0))
|
|
criticalError(FDB_EXIT_ERROR, "DLIterateError", "dl_iterate_phdr error");
|
|
phdr_cache_initialized = true;
|
|
}
|
|
|
|
// This overrides the function in libc!
|
|
extern "C" int dl_iterate_phdr(
|
|
int (*callback) (struct dl_phdr_info *info,
|
|
size_t size, void *data),
|
|
void *data)
|
|
{
|
|
interlockedIncrement64(&dl_iterate_phdr_calls);
|
|
|
|
if (phdr_cache_initialized)
|
|
{
|
|
// This path should be async signal safe
|
|
for(int i=0; i<phdr_cache.size(); i++)
|
|
{
|
|
int r = callback( (struct dl_phdr_info*)&phdr_cache[i][0], phdr_cache[i].size(), data );
|
|
if (r!=0)
|
|
return r;
|
|
}
|
|
return 0;
|
|
} else {
|
|
// This path is NOT async signal safe, and serves until and unless initSignalSafeUnwind() is called
|
|
initChain();
|
|
return chain_dl_iterate_phdr(callback, data);
|
|
}
|
|
}
|
|
|
|
#else // __linux__
|
|
|
|
void initSignalSafeUnwind() {}
|
|
|
|
#endif |