platform_system_core/init/mount_handler.h
Mark Salyzyn a73ed22cb7 init: add MountHandler property handler
Set properties dev.mnt.blk.<mount_point>=<device_block_class> for mount
and umount operations by setting up an Epoll handler to catch
EPOLLERR or EPOLLPRI signals when /proc/mounts is changed.  Only
update properties associated with block devices.  For the mount
point of /, use the designation of /root instead.

Can use the properties in init rc expansion like:

on property dev.mnt.blk.root=*
    write /sys/block/${dev.mnt.blk.root}/queue/read_ahead_kb ${boot_read_ahead_kb:-2048}

on property dev.mnt.blk.data=*
    write /sys/block/${dev.mnt.blk.data}/queue/read_ahead_kb ${boot_read_ahead_kb:-2048}

on late-fs
    setprop boot_read_ahead_kb 128
    write /sys/block/${dev.mnt.blk.root}/queue/read_ahead_kb ${boot_read_ahead_kb}
    write /sys/block/${dev.mnt.blk.data}/queue/read_ahead_kb ${boot_read_ahead_kb}

Test: boot and inspect getprop results.
Bug: 124072565
Change-Id: I1b8aff44f922ba372cd926de2919c215c40ee874
2019-03-15 11:54:38 -07:00

59 lines
1.6 KiB
C++

/*
* Copyright (C) 2019 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.
*/
#pragma once
#include <stdio.h>
#include <memory>
#include <set>
#include <string>
#include "epoll.h"
namespace android {
namespace init {
struct MountHandlerEntry {
MountHandlerEntry(const std::string& blk_device, const std::string& mount_point,
const std::string& fs_type);
bool operator<(const MountHandlerEntry& r) const;
const std::string blk_device;
const std::string mount_point;
const std::string fs_type;
};
class MountHandler {
public:
explicit MountHandler(Epoll* epoll);
MountHandler(const MountHandler&) = delete;
MountHandler(MountHandler&&) = delete;
MountHandler& operator=(const MountHandler&) = delete;
MountHandler& operator=(MountHandler&&) = delete;
~MountHandler();
private:
void MountHandlerFunction();
Epoll* epoll_;
std::unique_ptr<FILE, decltype(&fclose)> fp_;
std::set<MountHandlerEntry> mounts_;
};
} // namespace init
} // namespace android