1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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>
# define gettid() static_cast<pid_t>(syscall(SYS_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_SOLARIS)
#include <ucontext.h>
JS_STATIC_ASSERT(JS_STACK_GROWTH_DIRECTION < 0);
void*
js::GetNativeStackBaseImpl()
{
stack_t st;
stack_getbounds(&st);
return static_cast<char*>(st.ss_sp) + st.ss_size;
}
#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 */
|
