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Revert "Unregister pthread_atfork handlers on dlclose()"

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The visibility control in pthread_atfork.h is incorrect.
 It breaks 64bit libc.so by hiding pthread_atfork.

 This reverts commit 6df122f852.

Change-Id: I21e4b344d500c6f6de0ccb7420b916c4e233dd34
This commit is contained in:
Dimitry Ivanov
2015-04-24 03:45:59 +00:00
parent 6df122f852
commit 094f58fb2a
13 changed files with 41 additions and 261 deletions
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2
libc/Android.mk
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@@ -63,7 +63,6 @@ libc_common_src_files := \
stdio/sprintf.c \
stdio/stdio.c \
stdio/stdio_ext.cpp \
stdlib/atexit.c \
stdlib/exit.c \
# Fortify implementations of libc functions.
@@ -482,6 +481,7 @@ libc_upstream_openbsd_ndk_src_files := \
upstream-openbsd/lib/libc/stdio/wprintf.c \
upstream-openbsd/lib/libc/stdio/wscanf.c \
upstream-openbsd/lib/libc/stdio/wsetup.c \
upstream-openbsd/lib/libc/stdlib/atexit.c \
upstream-openbsd/lib/libc/stdlib/atoi.c \
upstream-openbsd/lib/libc/stdlib/atol.c \
upstream-openbsd/lib/libc/stdlib/atoll.c \

1
libc/arch-arm64/bionic/crtbegin.c
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@@ -67,4 +67,3 @@ __asm__ (
#include "../../arch-common/bionic/__dso_handle.h"
#include "../../arch-common/bionic/atexit.h"
#include "../../arch-common/bionic/pthread_atfork.h"

1
libc/arch-common/bionic/crtbegin.c
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@@ -59,7 +59,6 @@ void _start() {
#include "__dso_handle.h"
#include "atexit.h"
#include "pthread_atfork.h"
#ifdef __i386__
# include "../../arch-x86/bionic/__stack_chk_fail_local.h"
#endif

1
libc/arch-common/bionic/crtbegin_so.c
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@@ -56,7 +56,6 @@ void __on_dlclose() {
# include "__dso_handle_so.h"
# include "atexit.h"
#endif
#include "pthread_atfork.h"
#ifdef __i386__
# include "../../arch-x86/bionic/__stack_chk_fail_local.h"
#endif

29
libc/arch-common/bionic/pthread_atfork.h
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@@ -1,29 +0,0 @@
/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
extern void* __dso_handle;
extern int __register_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void), void* dso);
#ifndef _LIBC
// Libc used to export this in previous versions, therefore it needs
// to remain global for binary compatibility.
__attribute__ ((visibility ("hidden")))
#endif
int pthread_atfork(void (*prepare)(void), void (*parent)(void), void (*child)(void)) {
return __register_atfork(prepare, parent, child, &__dso_handle);
}

1
libc/arch-mips/bionic/crtbegin.c
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@@ -92,4 +92,3 @@ __asm__ (
#include "../../arch-common/bionic/__dso_handle.h"
#include "../../arch-common/bionic/atexit.h"
#include "../../arch-common/bionic/pthread_atfork.h"

122
libc/bionic/pthread_atfork.cpp
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@@ -30,8 +30,6 @@
#include <pthread.h>
#include <stdlib.h>
#include "private/bionic_macros.h"
struct atfork_t {
atfork_t* next;
atfork_t* prev;
@@ -39,143 +37,79 @@ struct atfork_t {
void (*prepare)(void);
void (*child)(void);
void (*parent)(void);
void* dso_handle;
};
class atfork_list_t {
public:
atfork_list_t() : first_(nullptr), last_(nullptr) {}
template<typename F>
void walk_forward(F f) {
for (atfork_t* it = first_; it != nullptr; it = it->next) {
f(it);
}
}
template<typename F>
void walk_backwards(F f) {
for (atfork_t* it = last_; it != nullptr; it = it->prev) {
f(it);
}
}
void push_back(atfork_t* entry) {
entry->next = nullptr;
entry->prev = last_;
if (entry->prev != nullptr) {
entry->prev->next = entry;
}
if (first_ == nullptr) {
first_ = entry;
}
last_ = entry;
}
template<typename F>
void remove_if(F predicate) {
atfork_t* it = first_;
while (it != nullptr) {
if (predicate(it)) {
atfork_t* entry = it;
it = it->next;
remove(entry);
} else {
it = it->next;
}
}
}
private:
void remove(atfork_t* entry) {
if (entry->prev != nullptr) {
entry->prev->next = entry->next;
} else {
first_ = entry->next;
}
if (entry->next != nullptr) {
entry->next->prev = entry->prev;
} else {
last_ = entry->prev;
}
free(entry);
}
atfork_t* first_;
atfork_t* last_;
DISALLOW_COPY_AND_ASSIGN(atfork_list_t);
struct atfork_list_t {
atfork_t* first;
atfork_t* last;
};
static pthread_mutex_t g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
static atfork_list_t g_atfork_list;
static atfork_list_t g_atfork_list = { NULL, NULL };
void __bionic_atfork_run_prepare() {
// We lock the atfork list here, unlock it in the parent, and reset it in the child.
// This ensures that nobody can modify the handler array between the calls
// to the prepare and parent/child handlers.
//
// TODO: If a handler tries to mutate the list, they'll block. We should probably copy
// the list before forking, and have prepare, parent, and child all work on the consistent copy.
pthread_mutex_lock(&g_atfork_list_mutex);
// Call pthread_atfork() prepare handlers. POSIX states that the prepare
// handlers should be called in the reverse order of the parent/child
// handlers, so we iterate backwards.
g_atfork_list.walk_backwards([](atfork_t* it) {
if (it->prepare != nullptr) {
for (atfork_t* it = g_atfork_list.last; it != NULL; it = it->prev) {
if (it->prepare != NULL) {
it->prepare();
}
});
}
}
void __bionic_atfork_run_child() {
g_atfork_list.walk_forward([](atfork_t* it) {
if (it->child != nullptr) {
for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
if (it->child != NULL) {
it->child();
}
});
}
g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
}
void __bionic_atfork_run_parent() {
g_atfork_list.walk_forward([](atfork_t* it) {
if (it->parent != nullptr) {
for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
if (it->parent != NULL) {
it->parent();
}
});
}
pthread_mutex_unlock(&g_atfork_list_mutex);
}
// __register_atfork is the name used by glibc
extern "C" int __register_atfork(void (*prepare)(void), void (*parent)(void),
void(*child)(void), void* dso) {
int pthread_atfork(void (*prepare)(void), void (*parent)(void), void(*child)(void)) {
atfork_t* entry = reinterpret_cast<atfork_t*>(malloc(sizeof(atfork_t)));
if (entry == nullptr) {
if (entry == NULL) {
return ENOMEM;
}
entry->prepare = prepare;
entry->parent = parent;
entry->child = child;
entry->dso_handle = dso;
pthread_mutex_lock(&g_atfork_list_mutex);
g_atfork_list.push_back(entry);
// Append 'entry' to the list.
entry->next = NULL;
entry->prev = g_atfork_list.last;
if (entry->prev != NULL) {
entry->prev->next = entry;
}
if (g_atfork_list.first == NULL) {
g_atfork_list.first = entry;
}
g_atfork_list.last = entry;
pthread_mutex_unlock(&g_atfork_list_mutex);
return 0;
}
extern "C" __LIBC_HIDDEN__ void __unregister_atfork(void* dso) {
pthread_mutex_lock(&g_atfork_list_mutex);
g_atfork_list.remove_if([&](const atfork_t* entry) {
return entry->dso_handle == dso;
});
pthread_mutex_unlock(&g_atfork_list_mutex);
}

16
libc/stdlib/atexit.c → libc/upstream-openbsd/lib/libc/stdlib/atexit.c
View File

@@ -35,15 +35,11 @@
#include <string.h>
#include <unistd.h>
#include "atexit.h"
#include "private/thread_private.h"
#include "thread_private.h"
struct atexit *__atexit;
static int restartloop;
/* BEGIN android-changed: __unregister_atfork is used by __cxa_finalize */
extern void __unregister_atfork(void* dso);
/* END android-changed */
/*
* Function pointers are stored in a linked list of pages. The list
* is initially empty, and pages are allocated on demand. The first
@@ -66,7 +62,7 @@ __cxa_atexit(void (*func)(void *), void *arg, void *dso)
{
struct atexit *p = __atexit;
struct atexit_fn *fnp;
size_t pgsize = getpagesize();
int pgsize = getpagesize();
int ret = -1;
if (pgsize < sizeof(*p))
@@ -165,12 +161,6 @@ restart:
__atexit = NULL;
}
_ATEXIT_UNLOCK();
/* BEGIN android-changed: call __unregister_atfork if dso is not null */
if (dso != NULL) {
__unregister_atfork(dso);
}
/* END android-changed */
}
/*
@@ -180,7 +170,7 @@ void
__atexit_register_cleanup(void (*func)(void))
{
struct atexit *p;
size_t pgsize = getpagesize();
int pgsize = getpagesize();
if (pgsize < sizeof(*p))
return;

0
libc/stdlib/atexit.h → libc/upstream-openbsd/lib/libc/stdlib/atexit.h
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