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/*
* Copyright (C) 2016 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "linker_gdb_support.h"
#include <pthread.h>
#include "private/ScopedPthreadMutexLocker.h"
// This function is an empty stub where GDB locates a breakpoint to get notified
// about linker activity.
extern "C"
void __attribute__((noinline)) __attribute__((visibility("default"))) rtld_db_dlactivity();
r_debug _r_debug =
{1, nullptr, reinterpret_cast<uintptr_t>(&rtld_db_dlactivity), r_debug::RT_CONSISTENT, 0};
static pthread_mutex_t g__r_debug_mutex = PTHREAD_MUTEX_INITIALIZER;
static link_map* r_debug_tail = nullptr;
void insert_link_map_into_debug_map(link_map* map) {
// Stick the new library at the end of the list.
// gdb tends to care more about libc than it does
// about leaf libraries, and ordering it this way
// reduces the back-and-forth over the wire.
if (r_debug_tail != nullptr) {
r_debug_tail->l_next = map;
map->l_prev = r_debug_tail;
map->l_next = nullptr;
} else {
_r_debug.r_map = map;
map->l_prev = nullptr;
map->l_next = nullptr;
}
r_debug_tail = map;
}
void remove_link_map_from_debug_map(link_map* map) {
if (r_debug_tail == map) {
r_debug_tail = map->l_prev;
}
if (map->l_prev) {
map->l_prev->l_next = map->l_next;
}
if (map->l_next) {
map->l_next->l_prev = map->l_prev;
}
}
void notify_gdb_of_load(link_map* map) {
ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
_r_debug.r_state = r_debug::RT_ADD;
rtld_db_dlactivity();
insert_link_map_into_debug_map(map);
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
}
void notify_gdb_of_unload(link_map* map) {
ScopedPthreadMutexLocker locker(&g__r_debug_mutex);
_r_debug.r_state = r_debug::RT_DELETE;
rtld_db_dlactivity();
remove_link_map_from_debug_map(map);
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
}
void notify_gdb_of_libraries() {
_r_debug.r_state = r_debug::RT_ADD;
rtld_db_dlactivity();
_r_debug.r_state = r_debug::RT_CONSISTENT;
rtld_db_dlactivity();
}