js/src/jsnativestack.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  * vim: set ts=8 sts=4 et sw=4 tw=99:
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "jsnativestack.h"
   8
   9 #ifdef XP_WIN
  10 # include "jswin.h"
  11
  12 #elif defined(XP_MACOSX) || defined(DARWIN) || defined(XP_UNIX)
  13 # include <pthread.h>
  14
  15 # if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
  16 #  include <pthread_np.h>
  17 # endif
  18
  19 # if defined(ANDROID)
  20 #  include <sys/types.h>
  21 #  include <unistd.h>
  22 # endif
  23
  24 #else
  25 # error "Unsupported platform"
  26
  27 #endif
  28
  29 #if defined(XP_WIN)
  30
  31 void*
  32 js::GetNativeStackBaseImpl()
  33 {
  34 # if defined(_M_IX86) && defined(_MSC_VER)
  35     /*
  36      * offset 0x18 from the FS segment register gives a pointer to
  37      * the thread information block for the current thread
  38      */
  39     NT_TIB* pTib;
  40     __asm {
  41         MOV EAX, FS:[18h]
  42         MOV pTib, EAX
  43     }
  44     return static_cast<void*>(pTib->StackBase);
  45
  46 # elif defined(_M_X64)
  47     PNT_TIB64 pTib = reinterpret_cast<PNT_TIB64>(NtCurrentTeb());
  48     return reinterpret_cast<void*>(pTib->StackBase);
  49
  50 # elif defined(_WIN32) && defined(__GNUC__)
  51     NT_TIB* pTib;
  52     asm ("movl %%fs:0x18, %0\n" : "=r" (pTib));
  53     return static_cast<void*>(pTib->StackBase);
  54
  55 # endif
  56 }
  57
  58 #elif defined(SOLARIS)
  59
  60 #include <ucontext.h>
  61
  62 JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
  63
  64 void*
  65 js::GetNativeStackBaseImpl()
  66 {
  67     stack_t st;
  68     stack_getbounds(&st);
  69     return static_cast<char*>(st.ss_sp) + st.ss_size;
  70 }
  71
  72 #elif defined(AIX)
  73
  74 #include <ucontext.h>
  75
  76 JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
  77
  78 void*
  79 js::GetNativeStackBaseImpl()
  80 {
  81     ucontext_t context;
  82     getcontext(&context);
  83     return static_cast<char*>(context.uc_stack.ss_sp) +
  84         context.uc_stack.ss_size;
  85 }
  86
  87 #else /* XP_UNIX */
  88
  89 void*
  90 js::GetNativeStackBaseImpl()
  91 {
  92     pthread_t thread = pthread_self();
  93 # if defined(XP_MACOSX) || defined(DARWIN)
  94     return pthread_get_stackaddr_np(thread);
  95
  96 # else
  97     pthread_attr_t sattr;
  98     pthread_attr_init(&sattr);
  99 #  if defined(__OpenBSD__)
 100     stack_t ss;
 101 #  elif defined(PTHREAD_NP_H) || defined(_PTHREAD_NP_H_) || defined(NETBSD)
 102     /* e.g. on FreeBSD 4.8 or newer, neundorf@kde.org */
 103     pthread_attr_get_np(thread, &sattr);
 104 #  else
 105     /*
 106      * FIXME: this function is non-portable;
 107      * other POSIX systems may have different np alternatives
 108      */
 109     pthread_getattr_np(thread, &sattr);
 110 #  endif
 111
 112     void* stackBase = 0;
 113     size_t stackSize = 0;
 114     int rc;
 115 # if defined(__OpenBSD__)
 116     rc = pthread_stackseg_np(pthread_self(), &ss);
 117     stackBase = (void*)((size_t) ss.ss_sp - ss.ss_size);
 118     stackSize = ss.ss_size;
 119 # elif defined(ANDROID)
 120     if (gettid() == getpid()) {
 121         // bionic's pthread_attr_getstack doesn't tell the truth for the main
 122         // thread (see bug 846670). So we scan /proc/self/maps to find the
 123         // segment which contains the stack.
 124         rc = -1;
 125         FILE* fs = fopen("/proc/self/maps", "r");
 126         if (fs) {
 127             char line[100];
 128             unsigned long stackAddr = (unsigned long)&sattr;
 129             while (fgets(line, sizeof(line), fs) != nullptr) {
 130                 unsigned long stackStart;
 131                 unsigned long stackEnd;
 132                 if (sscanf(line, "%lx-%lx ", &stackStart, &stackEnd) == 2 &&
 133                     stackAddr >= stackStart && stackAddr < stackEnd) {
 134                     stackBase = (void*)stackStart;
 135                     stackSize = stackEnd - stackStart;
 136                     rc = 0;
 137                     break;
 138                 }
 139             }
 140             fclose(fs);
 141         }
 142     } else
 143         // For non main-threads pthread allocates the stack itself so it tells
 144         // the truth.
 145         rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
 146 # else
 147     rc = pthread_attr_getstack(&sattr, &stackBase, &stackSize);
 148 # endif
 149     if (rc)
 150         MOZ_CRASH();
 151     MOZ_ASSERT(stackBase);
 152     pthread_attr_destroy(&sattr);
 153
 154 #  if JS_STACK_GROWTH_DIRECTION > 0
 155     return stackBase;
 156 #  else
 157     return static_cast<char*>(stackBase) + stackSize;
 158 #  endif
 159 # endif
 160 }
 161
 162 #endif /* !XP_WIN */