2946cd7010
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
140 lines
4.7 KiB
C++
140 lines
4.7 KiB
C++
//=-- lsan_common_linux.cc ------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of LeakSanitizer.
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// Implementation of common leak checking functionality. Linux-specific code.
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//
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//===----------------------------------------------------------------------===//
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#include "sanitizer_common/sanitizer_platform.h"
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#include "lsan_common.h"
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#if CAN_SANITIZE_LEAKS && SANITIZER_LINUX
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#include <link.h>
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#include "sanitizer_common/sanitizer_common.h"
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#include "sanitizer_common/sanitizer_flags.h"
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#include "sanitizer_common/sanitizer_getauxval.h"
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#include "sanitizer_common/sanitizer_linux.h"
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#include "sanitizer_common/sanitizer_stackdepot.h"
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namespace __lsan {
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static const char kLinkerName[] = "ld";
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static char linker_placeholder[sizeof(LoadedModule)] ALIGNED(64);
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static LoadedModule *linker = nullptr;
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static bool IsLinker(const LoadedModule& module) {
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#if SANITIZER_USE_GETAUXVAL
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return module.base_address() == getauxval(AT_BASE);
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#else
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return LibraryNameIs(module.full_name(), kLinkerName);
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#endif // SANITIZER_USE_GETAUXVAL
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}
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__attribute__((tls_model("initial-exec")))
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THREADLOCAL int disable_counter;
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bool DisabledInThisThread() { return disable_counter > 0; }
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void DisableInThisThread() { disable_counter++; }
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void EnableInThisThread() {
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if (disable_counter == 0) {
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DisableCounterUnderflow();
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}
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disable_counter--;
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}
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void InitializePlatformSpecificModules() {
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ListOfModules modules;
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modules.init();
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for (LoadedModule &module : modules) {
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if (!IsLinker(module))
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continue;
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if (linker == nullptr) {
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linker = reinterpret_cast<LoadedModule *>(linker_placeholder);
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*linker = module;
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module = LoadedModule();
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} else {
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VReport(1, "LeakSanitizer: Multiple modules match \"%s\". "
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"TLS and other allocations originating from linker might be "
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"falsely reported as leaks.\n", kLinkerName);
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linker->clear();
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linker = nullptr;
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return;
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}
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}
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if (linker == nullptr) {
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VReport(1, "LeakSanitizer: Dynamic linker not found. TLS and other "
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"allocations originating from linker might be falsely reported "
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"as leaks.\n");
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}
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}
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static int ProcessGlobalRegionsCallback(struct dl_phdr_info *info, size_t size,
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void *data) {
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Frontier *frontier = reinterpret_cast<Frontier *>(data);
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for (uptr j = 0; j < info->dlpi_phnum; j++) {
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const ElfW(Phdr) *phdr = &(info->dlpi_phdr[j]);
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// We're looking for .data and .bss sections, which reside in writeable,
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// loadable segments.
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if (!(phdr->p_flags & PF_W) || (phdr->p_type != PT_LOAD) ||
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(phdr->p_memsz == 0))
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continue;
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uptr begin = info->dlpi_addr + phdr->p_vaddr;
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uptr end = begin + phdr->p_memsz;
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ScanGlobalRange(begin, end, frontier);
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}
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return 0;
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}
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// Scans global variables for heap pointers.
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void ProcessGlobalRegions(Frontier *frontier) {
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if (!flags()->use_globals) return;
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dl_iterate_phdr(ProcessGlobalRegionsCallback, frontier);
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}
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LoadedModule *GetLinker() { return linker; }
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void ProcessPlatformSpecificAllocations(Frontier *frontier) {}
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struct DoStopTheWorldParam {
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StopTheWorldCallback callback;
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void *argument;
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};
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// While calling Die() here is undefined behavior and can potentially
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// cause race conditions, it isn't possible to intercept exit on linux,
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// so we have no choice but to call Die() from the atexit handler.
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void HandleLeaks() {
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if (common_flags()->exitcode) Die();
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}
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static int DoStopTheWorldCallback(struct dl_phdr_info *info, size_t size,
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void *data) {
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DoStopTheWorldParam *param = reinterpret_cast<DoStopTheWorldParam *>(data);
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StopTheWorld(param->callback, param->argument);
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return 1;
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}
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// LSan calls dl_iterate_phdr() from the tracer task. This may deadlock: if one
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// of the threads is frozen while holding the libdl lock, the tracer will hang
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// in dl_iterate_phdr() forever.
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// Luckily, (a) the lock is reentrant and (b) libc can't distinguish between the
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// tracer task and the thread that spawned it. Thus, if we run the tracer task
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// while holding the libdl lock in the parent thread, we can safely reenter it
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// in the tracer. The solution is to run stoptheworld from a dl_iterate_phdr()
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// callback in the parent thread.
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void DoStopTheWorld(StopTheWorldCallback callback, void *argument) {
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DoStopTheWorldParam param = {callback, argument};
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dl_iterate_phdr(DoStopTheWorldCallback, ¶m);
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}
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} // namespace __lsan
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#endif // CAN_SANITIZE_LEAKS && SANITIZER_LINUX
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