Unregister pthread_atfork handlers on dlclose()
Bug: http://b/20339788
Change-Id: I874c87faa377645fa9e0752f4fc166d81fd9ef7e
diff --git a/libc/Android.mk b/libc/Android.mk
index 2175dc4..a9fed2c 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -63,6 +63,7 @@
stdio/sprintf.c \
stdio/stdio.c \
stdio/stdio_ext.cpp \
+ stdlib/atexit.c \
stdlib/exit.c \
# Fortify implementations of libc functions.
@@ -482,7 +483,6 @@
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 \
@@ -1340,10 +1340,13 @@
LOCAL_C_INCLUDES := $(libc_common_c_includes)
LOCAL_SRC_FILES := \
+ arch-common/bionic/crtbegin_so.c \
+ arch-common/bionic/crtbrand.S \
$(libc_arch_dynamic_src_files) \
bionic/malloc_debug_common.cpp \
bionic/libc_init_dynamic.cpp \
bionic/NetdClient.cpp \
+ arch-common/bionic/crtend_so.S \
LOCAL_MODULE := libc
LOCAL_CLANG := $(use_clang)
@@ -1388,15 +1391,15 @@
$(eval $(call patch-up-arch-specific-flags,LOCAL_CFLAGS,libc_common_cflags))
$(eval $(call patch-up-arch-specific-flags,LOCAL_SRC_FILES,libc_arch_dynamic_src_files))
+
+LOCAL_NO_CRT := true
+LOCAL_ASFLAGS += $(libc_crt_target_cflags)
+
# special for arm
-LOCAL_NO_CRT_arm := true
LOCAL_CFLAGS_arm += -DCRT_LEGACY_WORKAROUND
-LOCAL_ASFLAGS_arm += $(libc_crt_target_cflags)
LOCAL_SRC_FILES_arm += \
- arch-common/bionic/crtbegin_so.c \
- arch-common/bionic/crtbrand.S \
- arch-arm/bionic/atexit_legacy.c \
- arch-common/bionic/crtend_so.S
+ arch-arm/bionic/atexit_legacy.c
+
LOCAL_ADDRESS_SANITIZER := false
LOCAL_NATIVE_COVERAGE := $(bionic_coverage)
diff --git a/libc/arch-arm64/bionic/crtbegin.c b/libc/arch-arm64/bionic/crtbegin.c
index fec0b11..7e2c5d7 100644
--- a/libc/arch-arm64/bionic/crtbegin.c
+++ b/libc/arch-arm64/bionic/crtbegin.c
@@ -67,3 +67,4 @@
#include "../../arch-common/bionic/__dso_handle.h"
#include "../../arch-common/bionic/atexit.h"
+#include "../../arch-common/bionic/pthread_atfork.h"
diff --git a/libc/arch-common/bionic/crtbegin.c b/libc/arch-common/bionic/crtbegin.c
index fa9f3f3..c46405c 100644
--- a/libc/arch-common/bionic/crtbegin.c
+++ b/libc/arch-common/bionic/crtbegin.c
@@ -59,6 +59,7 @@
#include "__dso_handle.h"
#include "atexit.h"
+#include "pthread_atfork.h"
#ifdef __i386__
# include "../../arch-x86/bionic/__stack_chk_fail_local.h"
#endif
diff --git a/libc/arch-common/bionic/crtbegin_so.c b/libc/arch-common/bionic/crtbegin_so.c
index 641e45a..3754363 100644
--- a/libc/arch-common/bionic/crtbegin_so.c
+++ b/libc/arch-common/bionic/crtbegin_so.c
@@ -56,6 +56,7 @@
# 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
diff --git a/libc/arch-common/bionic/pthread_atfork.h b/libc/arch-common/bionic/pthread_atfork.h
new file mode 100644
index 0000000..0c48a12
--- /dev/null
+++ b/libc/arch-common/bionic/pthread_atfork.h
@@ -0,0 +1,29 @@
+/*
+ * 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);
+}
+
diff --git a/libc/arch-mips/bionic/crtbegin.c b/libc/arch-mips/bionic/crtbegin.c
index 50e9eeb..d72ec7b 100644
--- a/libc/arch-mips/bionic/crtbegin.c
+++ b/libc/arch-mips/bionic/crtbegin.c
@@ -92,3 +92,4 @@
#include "../../arch-common/bionic/__dso_handle.h"
#include "../../arch-common/bionic/atexit.h"
+#include "../../arch-common/bionic/pthread_atfork.h"
diff --git a/libc/bionic/pthread_atfork.cpp b/libc/bionic/pthread_atfork.cpp
index d1c4ad0..093ffd2 100644
--- a/libc/bionic/pthread_atfork.cpp
+++ b/libc/bionic/pthread_atfork.cpp
@@ -30,6 +30,8 @@
#include <pthread.h>
#include <stdlib.h>
+#include "private/bionic_macros.h"
+
struct atfork_t {
atfork_t* next;
atfork_t* prev;
@@ -37,79 +39,143 @@
void (*prepare)(void);
void (*child)(void);
void (*parent)(void);
+
+ void* dso_handle;
};
-struct atfork_list_t {
- atfork_t* first;
- atfork_t* last;
+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);
};
static pthread_mutex_t g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
-static atfork_list_t g_atfork_list = { NULL, NULL };
+static atfork_list_t g_atfork_list;
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.
- for (atfork_t* it = g_atfork_list.last; it != NULL; it = it->prev) {
- if (it->prepare != NULL) {
+ g_atfork_list.walk_backwards([](atfork_t* it) {
+ if (it->prepare != nullptr) {
it->prepare();
}
- }
+ });
}
void __bionic_atfork_run_child() {
- for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
- if (it->child != NULL) {
+ g_atfork_list.walk_forward([](atfork_t* it) {
+ if (it->child != nullptr) {
it->child();
}
- }
+ });
g_atfork_list_mutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
}
void __bionic_atfork_run_parent() {
- for (atfork_t* it = g_atfork_list.first; it != NULL; it = it->next) {
- if (it->parent != NULL) {
+ g_atfork_list.walk_forward([](atfork_t* it) {
+ if (it->parent != nullptr) {
it->parent();
}
- }
+ });
pthread_mutex_unlock(&g_atfork_list_mutex);
}
-int pthread_atfork(void (*prepare)(void), void (*parent)(void), void(*child)(void)) {
+// __register_atfork is the name used by glibc
+extern "C" int __register_atfork(void (*prepare)(void), void (*parent)(void),
+ void(*child)(void), void* dso) {
atfork_t* entry = reinterpret_cast<atfork_t*>(malloc(sizeof(atfork_t)));
- if (entry == NULL) {
+ if (entry == nullptr) {
return ENOMEM;
}
entry->prepare = prepare;
entry->parent = parent;
entry->child = child;
+ entry->dso_handle = dso;
pthread_mutex_lock(&g_atfork_list_mutex);
- // 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;
+ g_atfork_list.push_back(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);
+}
+
diff --git a/libc/upstream-openbsd/lib/libc/stdlib/atexit.c b/libc/stdlib/atexit.c
similarity index 92%
rename from libc/upstream-openbsd/lib/libc/stdlib/atexit.c
rename to libc/stdlib/atexit.c
index 6532b38..df2b1b5 100644
--- a/libc/upstream-openbsd/lib/libc/stdlib/atexit.c
+++ b/libc/stdlib/atexit.c
@@ -35,11 +35,15 @@
#include <string.h>
#include <unistd.h>
#include "atexit.h"
-#include "thread_private.h"
+#include "private/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
@@ -62,7 +66,7 @@
{
struct atexit *p = __atexit;
struct atexit_fn *fnp;
- int pgsize = getpagesize();
+ size_t pgsize = getpagesize();
int ret = -1;
if (pgsize < sizeof(*p))
@@ -161,6 +165,12 @@
__atexit = NULL;
}
_ATEXIT_UNLOCK();
+
+ /* BEGIN android-changed: call __unregister_atfork if dso is not null */
+ if (dso != NULL) {
+ __unregister_atfork(dso);
+ }
+ /* END android-changed */
}
/*
@@ -170,7 +180,7 @@
__atexit_register_cleanup(void (*func)(void))
{
struct atexit *p;
- int pgsize = getpagesize();
+ size_t pgsize = getpagesize();
if (pgsize < sizeof(*p))
return;
diff --git a/libc/upstream-openbsd/lib/libc/stdlib/atexit.h b/libc/stdlib/atexit.h
similarity index 100%
rename from libc/upstream-openbsd/lib/libc/stdlib/atexit.h
rename to libc/stdlib/atexit.h