platform_system_core/libsuspend/autosuspend.c
Kyle Russell a26b4caf4c autosuspend_inited flag set even if initialization fails
Prevents possible SIGSEGV on second autosuspend_enable attempt when
first intialization attempt fails.  autosuspend_inited should only
be set once autosuspend_ops has been assigned.

Consider the first call to autosuspend_enable().
autosuspend_init() sets its inited flag to true, and attempts to
set autosuspend_ops.  If all the other autosuspend_*_init() attempts
fail, autosuspend_init() returns -1, which autosuspend_enable()
will return as a failure.  A second call to autosuspend_enable()
will check autosuspend_init() and see that autosuspend has already
been initialized.  It will attempt to access autosuspend_ops, which
were not set in the first initialization attempt, causing a SIGSEGV.

Change-Id: Ib2d3ee62fee4c3b6d0323e5b7f3709a23c6b923f
2012-11-20 09:12:39 -05:00

109 lines
2.1 KiB
C

/*
* Copyright (C) 2012 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.
*/
#include <stdbool.h>
#define LOG_TAG "libsuspend"
#include <cutils/log.h>
#include <suspend/autosuspend.h>
#include "autosuspend_ops.h"
static struct autosuspend_ops *autosuspend_ops;
static bool autosuspend_enabled;
static bool autosuspend_inited;
static int autosuspend_init(void)
{
if (autosuspend_inited) {
return 0;
}
autosuspend_ops = autosuspend_earlysuspend_init();
if (autosuspend_ops) {
goto out;
}
autosuspend_ops = autosuspend_autosleep_init();
if (autosuspend_ops) {
goto out;
}
autosuspend_ops = autosuspend_wakeup_count_init();
if (autosuspend_ops) {
goto out;
}
if (!autosuspend_ops) {
ALOGE("failed to initialize autosuspend\n");
return -1;
}
out:
autosuspend_inited = true;
ALOGV("autosuspend initialized\n");
return 0;
}
int autosuspend_enable(void)
{
int ret;
ret = autosuspend_init();
if (ret) {
return ret;
}
ALOGV("autosuspend_enable\n");
if (autosuspend_enabled) {
return 0;
}
ret = autosuspend_ops->enable();
if (ret) {
return ret;
}
autosuspend_enabled = true;
return 0;
}
int autosuspend_disable(void)
{
int ret;
ret = autosuspend_init();
if (ret) {
return ret;
}
ALOGV("autosuspend_disable\n");
if (!autosuspend_enabled) {
return 0;
}
ret = autosuspend_ops->disable();
if (ret) {
return ret;
}
autosuspend_enabled = false;
return 0;
}