gecko-dev/mozglue/build/BionicGlue.cpp

199 lines
5.2 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 <pthread.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <android/log.h>
#include <sys/syscall.h>
#include "mozilla/Alignment.h"
#include <vector>
#define NS_EXPORT __attribute__ ((visibility("default")))
#if ANDROID_VERSION < 17 || defined(MOZ_WIDGET_ANDROID)
/* Android doesn't have pthread_atfork(), so we need to use our own. */
struct AtForkFuncs {
void (*prepare)(void);
void (*parent)(void);
void (*child)(void);
};
/* jemalloc's initialization calls pthread_atfork. When pthread_atfork (see
* further below) stores the corresponding data, it's going to allocate memory,
* which will loop back to jemalloc's initialization, leading to a dead-lock.
* So, for that specific vector, we use a special allocator that returns a
* static buffer for small sizes, and force the initial vector capacity to
* a size enough to store one atfork function table. */
template <typename T>
struct SpecialAllocator: public std::allocator<T>
{
SpecialAllocator(): bufUsed(false) {}
inline typename std::allocator<T>::pointer allocate(typename std::allocator<T>::size_type n, const void * = 0) {
if (!bufUsed && n == 1) {
bufUsed = true;
return buf.addr();
}
return reinterpret_cast<T *>(::operator new(sizeof(T) * n));
}
inline void deallocate(typename std::allocator<T>::pointer p, typename std::allocator<T>::size_type n) {
if (p == buf.addr())
bufUsed = false;
else
::operator delete(p);
}
template<typename U>
struct rebind {
typedef SpecialAllocator<U> other;
};
private:
mozilla::AlignedStorage2<T> buf;
bool bufUsed;
};
static std::vector<AtForkFuncs, SpecialAllocator<AtForkFuncs> > atfork;
#endif
#ifdef MOZ_WIDGET_GONK
#include "cpuacct.h"
#if ANDROID_VERSION < 17 || defined(MOZ_WIDGET_ANDROID)
extern "C" NS_EXPORT int
timer_create(clockid_t, struct sigevent*, timer_t*)
{
__android_log_print(ANDROID_LOG_ERROR, "BionicGlue", "timer_create not supported!");
abort();
return -1;
}
#endif
#else
#define cpuacct_add(x)
#endif
#if ANDROID_VERSION < 17 || defined(MOZ_WIDGET_ANDROID)
extern "C" NS_EXPORT int
pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void))
{
AtForkFuncs funcs;
funcs.prepare = prepare;
funcs.parent = parent;
funcs.child = child;
if (!atfork.capacity())
atfork.reserve(1);
atfork.push_back(funcs);
return 0;
}
extern "C" NS_EXPORT pid_t __fork(void);
extern "C" NS_EXPORT pid_t
fork(void)
{
pid_t pid;
for (auto it = atfork.rbegin();
it < atfork.rend(); ++it)
if (it->prepare)
it->prepare();
switch ((pid = syscall(__NR_clone, SIGCHLD, NULL, NULL, NULL, NULL))) {
case 0:
cpuacct_add(getuid());
for (auto it = atfork.begin();
it < atfork.end(); ++it)
if (it->child)
it->child();
break;
default:
for (auto it = atfork.begin();
it < atfork.end(); ++it)
if (it->parent)
it->parent();
}
return pid;
}
#endif
extern "C" NS_EXPORT int
raise(int sig)
{
// Bug 741272: Bionic incorrectly uses kill(), which signals the
// process, and thus could signal another thread (and let this one
// return "successfully" from raising a fatal signal).
//
// Bug 943170: POSIX specifies pthread_kill(pthread_self(), sig) as
// equivalent to raise(sig), but Bionic also has a bug with these
// functions, where a forked child will kill its parent instead.
extern pid_t gettid(void);
return syscall(__NR_tgkill, getpid(), gettid(), sig);
}
/*
* The following wrappers for PR_Xxx are needed until we can get
* PR_DuplicateEnvironment landed in NSPR.
* See see bug 772734 and bug 773414.
*
* We can't #include the pr headers here, and we can't call any of the
* PR/PL functions either, so we just reimplemnt using native code.
*/
static pthread_mutex_t _pr_envLock = PTHREAD_MUTEX_INITIALIZER;
extern "C" NS_EXPORT char*
__wrap_PR_GetEnv(const char *var)
{
char *ev;
pthread_mutex_lock(&_pr_envLock);
ev = getenv(var);
pthread_mutex_unlock(&_pr_envLock);
return ev;
}
extern "C" NS_EXPORT int
__wrap_PR_SetEnv(const char *string)
{
int result;
if ( !strchr(string, '=')) return(-1);
pthread_mutex_lock(&_pr_envLock);
result = putenv(const_cast<char*>(string));
pthread_mutex_unlock(&_pr_envLock);
return (result)? -1 : 0;
}
extern "C" NS_EXPORT pthread_mutex_t *
PR_GetEnvLock(void)
{
return &_pr_envLock;
}
/* Flash plugin uses symbols that are not present in Android >= 4.4 */
#ifndef MOZ_WIDGET_GONK
namespace android {
namespace VectorImpl {
NS_EXPORT void reservedVectorImpl1(void) { }
NS_EXPORT void reservedVectorImpl2(void) { }
NS_EXPORT void reservedVectorImpl3(void) { }
NS_EXPORT void reservedVectorImpl4(void) { }
NS_EXPORT void reservedVectorImpl5(void) { }
NS_EXPORT void reservedVectorImpl6(void) { }
NS_EXPORT void reservedVectorImpl7(void) { }
NS_EXPORT void reservedVectorImpl8(void) { }
}
}
#endif