/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sts=4 et sw=4 tw=99: * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #include "jsnativestack.h" #ifdef XP_WIN # include "jswin.h" #elif defined(XP_DARWIN) || defined(DARWIN) || defined(XP_UNIX) # include <pthread.h> # if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) # include <pthread_np.h> # endif # if defined(ANDROID) # include <sys/types.h> # include <unistd.h> # endif # if defined(XP_LINUX) && !defined(ANDROID) && defined(__GLIBC__) # include <dlfcn.h> # include <sys/syscall.h> # include <sys/types.h> # include <unistd.h> static pid_t gettid() { return syscall(__NR_gettid); } # endif #else # error "Unsupported platform" #endif #if defined(XP_WIN) void* js::GetNativeStackBaseImpl() { # if defined(_M_IX86) && defined(_MSC_VER) /* * offset 0x18 from the FS segment register gives a pointer to * the thread information block for the current thread */ NT_TIB* pTib; __asm { MOV EAX, FS:[18h] MOV pTib, EAX } return static_cast<void*>(pTib->StackBase); # elif defined(_M_X64) PNT_TIB64 pTib = reinterpret_cast<PNT_TIB64>(NtCurrentTeb()); return reinterpret_cast<void*>(pTib->StackBase); # elif defined(_M_ARM) PNT_TIB pTib = reinterpret_cast<PNT_TIB>(NtCurrentTeb()); return static_cast<void*>(pTib->StackBase); # elif defined(_WIN32) && defined(__GNUC__) NT_TIB* pTib; asm ("movl %%fs:0x18, %0\n" : "=r" (pTib)); return static_cast<void*>(pTib->StackBase); # endif } #elif defined(XP_LINUX) && !defined(ANDROID) && defined(__GLIBC__) void* js::GetNativeStackBaseImpl() { // On the main thread, get stack base from glibc's __libc_stack_end rather than pthread APIs // to avoid filesystem calls /proc/self/maps. Non-main threads spawned with pthreads can read // this information directly from their pthread struct, but when using the pthreads API, the // main thread must go parse /proc/self/maps to figure the mapped stack address space ranges. // We want to avoid reading from /proc/ so that the application can run in restricted // environments where /proc may not be mounted (e.g. chroot). if (gettid() == getpid()) { void** pLibcStackEnd = (void**)dlsym(RTLD_DEFAULT, "__libc_stack_end"); // If __libc_stack_end is not found, architecture specific frame pointer hopping will need // to be implemented. MOZ_RELEASE_ASSERT(pLibcStackEnd, "__libc_stack_end unavailable, unable to setup stack range for JS."); void* stackBase = *pLibcStackEnd; MOZ_RELEASE_ASSERT(stackBase, "Invalid stack base, unable to setup stack range for JS."); // We don't need to fix stackBase, as it already roughly points to beginning of the stack. return stackBase; } // Non-main threads have the required info stored in memory, so no filesystem calls are made. pthread_t thread = pthread_self(); pthread_attr_t sattr; pthread_attr_init(&sattr); pthread_getattr_np(thread, &sattr); // stackBase will be the *lowest* address on all architectures. void* stackBase = nullptr; size_t stackSize = 0; int rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize); if (rc) { MOZ_CRASH("Call to pthread_attr_getstack failed, unable to setup stack range for JS."); } MOZ_RELEASE_ASSERT(stackBase, "Invalid stack base, unable to setup stack range for JS."); pthread_attr_destroy(&sattr); # if JS_STACK_GROWTH_DIRECTION > 0 return stackBase; # else return static_cast<char*>(stackBase) + stackSize; # endif } #else /* XP_UNIX */ void* js::GetNativeStackBaseImpl() { pthread_t thread = pthread_self(); # if defined(XP_DARWIN) || defined(DARWIN) return pthread_get_stackaddr_np(thread); # else pthread_attr_t sattr; pthread_attr_init(&sattr); # if defined(__OpenBSD__) stack_t ss; # elif defined(PTHREAD_NP_H) || defined(_PTHREAD_NP_H_) || defined(NETBSD) /* e.g. on FreeBSD 4.8 or newer, neundorf@kde.org */ pthread_attr_get_np(thread, &sattr); # else /* * FIXME: this function is non-portable; * other POSIX systems may have different np alternatives */ pthread_getattr_np(thread, &sattr); # endif void* stackBase = 0; size_t stackSize = 0; int rc; # if defined(__OpenBSD__) rc = pthread_stackseg_np(pthread_self(), &ss); stackBase = (void*)((size_t) ss.ss_sp - ss.ss_size); stackSize = ss.ss_size; # elif defined(ANDROID) if (gettid() == getpid()) { // bionic's pthread_attr_getstack doesn't tell the truth for the main // thread (see bug 846670). So we scan /proc/self/maps to find the // segment which contains the stack. rc = -1; // Put the string on the stack, otherwise there is the danger that it // has not been decompressed by the the on-demand linker. Bug 1165460. // // The volatile keyword should stop the compiler from trying to omit // the stack copy in the future (hopefully). volatile char path[] = "/proc/self/maps"; FILE* fs = fopen((const char*)path, "r"); if (fs) { char line[100]; unsigned long stackAddr = (unsigned long)&sattr; while (fgets(line, sizeof(line), fs) != nullptr) { unsigned long stackStart; unsigned long stackEnd; if (sscanf(line, "%lx-%lx ", &stackStart, &stackEnd) == 2 && stackAddr >= stackStart && stackAddr < stackEnd) { stackBase = (void*)stackStart; stackSize = stackEnd - stackStart; rc = 0; break; } } fclose(fs); } } else // For non main-threads pthread allocates the stack itself so it tells // the truth. rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize); # else // Use the default pthread_attr_getstack() call. Note that this function // differs between libc implementations and could imply /proc access etc. // which may not work in restricted environments. rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize); # endif if (rc) { MOZ_CRASH("Call to pthread_attr_getstack failed, unable to setup stack range for JS."); } MOZ_RELEASE_ASSERT(stackBase, "Invalid stack base, unable to setup stack range for JS."); pthread_attr_destroy(&sattr); # if JS_STACK_GROWTH_DIRECTION > 0 return stackBase; # else return static_cast<char*>(stackBase) + stackSize; # endif # endif } #endif /* !XP_WIN */