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Commit 67665a45 authored by David Anderson's avatar David Anderson Committed by Gerrit Code Review
Browse files

Merge changes I49495684,I0db2e0f4,I07bb811b 

* changes:
  init: Initiate other misc devices from BlockDevInitializer.
  Allow snapuserd to be included in the initial ramdisk.
  Add experimental daemon for handling dm-user requests.
parents ba1bd64c 67cd9f09

fs_mgr/libdm/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ cc_library_static { 
            enabled: false,

        },

    },

    ramdisk_available: true,

}



filegroup {

fs_mgr/libsnapshot/Android.bp

+33 −0
Original line number Diff line number Diff line
@@ -310,3 +310,36 @@ cc_test { 
    auto_gen_config: true,

    require_root: true,

}



cc_defaults {

    name: "snapuserd_defaults",

    srcs: [

        "snapuserd.cpp",

    ],



    cflags: [

        "-Wall",

        "-Werror"

    ],



    static_libs: [

        "libbase",

        "liblog",

        "libdm",

    ],

}



cc_binary {

    name: "snapuserd",

    defaults: ["snapuserd_defaults"],

}



cc_binary {

    name: "snapuserd_ramdisk",

    stem: "snapuserd",

    defaults: ["snapuserd_defaults"],



    ramdisk: true,

    static_executable: true,

    system_shared_libs: [],

}

fs_mgr/libsnapshot/snapuserd.cpp

0 → 100644
+126 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2020 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 <linux/types.h>



#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/stringprintf.h>

#include <android-base/unique_fd.h>

#include <libdm/dm.h>



using android::base::unique_fd;



#define DM_USER_MAP_READ 0

#define DM_USER_MAP_WRITE 1



struct dm_user_message {

    __u64 seq;

    __u64 type;

    __u64 flags;

    __u64 sector;

    __u64 len;

    __u8 buf[];

};



using namespace android::dm;



static int daemon_main(const std::string& device) {

    unique_fd block_fd(open(device.c_str(), O_RDWR));

    if (block_fd < 0) {

        PLOG(ERROR) << "Unable to open " << device;

        return 1;

    }



    unique_fd ctrl_fd(open("/dev/dm-user", O_RDWR));

    if (ctrl_fd < 0) {

        PLOG(ERROR) << "Unable to open /dev/dm-user";

        return 1;

    }



    size_t buf_size = 1UL << 16;

    auto buf = std::make_unique<char>(buf_size);



    /* Just keeps pumping messages between userspace and the kernel.  We won't

     * actually be doing anything, but the sequence numbers line up so it'll at

     * least make forward progress. */

    while (true) {

        struct dm_user_message* msg = (struct dm_user_message*)buf.get();



        memset(buf.get(), 0, buf_size);



        ssize_t readed = read(ctrl_fd.get(), buf.get(), buf_size);

        if (readed < 0) {

            PLOG(ERROR) << "Control read failed, trying with more space";

            buf_size *= 2;

            buf = std::make_unique<char>(buf_size);

            continue;

        }



        LOG(DEBUG) << android::base::StringPrintf("read() from dm-user returned %d bytes:",

                                                  (int)readed);

        LOG(DEBUG) << android::base::StringPrintf("    msg->seq:    0x%016llx", msg->seq);

        LOG(DEBUG) << android::base::StringPrintf("    msg->type:   0x%016llx", msg->type);

        LOG(DEBUG) << android::base::StringPrintf("    msg->flags:  0x%016llx", msg->flags);

        LOG(DEBUG) << android::base::StringPrintf("    msg->sector: 0x%016llx", msg->sector);

        LOG(DEBUG) << android::base::StringPrintf("    msg->len:    0x%016llx", msg->len);



        switch (msg->type) {

            case DM_USER_MAP_READ: {

                LOG(DEBUG) << android::base::StringPrintf(

                        "Responding to read of sector %lld with %lld bytes data", msg->sector,

                        msg->len);



                if ((sizeof(*msg) + msg->len) > buf_size) {

                    auto old_buf = std::move(buf);

                    buf_size = sizeof(*msg) + msg->len;

                    buf = std::make_unique<char>(buf_size);

                    memcpy(buf.get(), old_buf.get(), sizeof(*msg));

                    msg = (struct dm_user_message*)buf.get();

                }



                if (lseek(block_fd.get(), msg->sector * 512, SEEK_SET) < 0) {

                    PLOG(ERROR) << "lseek failed: " << device;

                    return 7;

                }

                if (!android::base::ReadFully(block_fd.get(), msg->buf, msg->len)) {

                    PLOG(ERROR) << "read failed: " << device;

                    return 7;

                }



                if (!android::base::WriteFully(ctrl_fd.get(), buf.get(), sizeof(*msg) + msg->len)) {

                    PLOG(ERROR) << "write control failed";

                    return 3;

                }

                break;

            }



            case DM_USER_MAP_WRITE:

                abort();

                break;

        }



        LOG(DEBUG) << "read() finished, next message";

    }



    return 0;

}



int main([[maybe_unused]] int argc, char** argv) {

    android::base::InitLogging(argv, &android::base::KernelLogger);

    daemon_main(argv[1]);

    return 0;

}

init/block_dev_initializer.cpp

+12 −4
Original line number Diff line number Diff line
@@ -37,7 +37,15 @@ BlockDevInitializer::BlockDevInitializer() : uevent_listener_(16 * 1024 * 1024) 
}



bool BlockDevInitializer::InitDeviceMapper() {

    const std::string dm_path = "/devices/virtual/misc/device-mapper";

    return InitMiscDevice("device-mapper");

}



bool BlockDevInitializer::InitDmUser() {

    return InitMiscDevice("dm-user");

}



bool BlockDevInitializer::InitMiscDevice(const std::string& name) {

    const std::string dm_path = "/devices/virtual/misc/" + name;

    bool found = false;

    auto dm_callback = [this, &dm_path, &found](const Uevent& uevent) {

        if (uevent.path == dm_path) {
@@ -49,13 +57,13 @@ bool BlockDevInitializer::InitDeviceMapper() { 
    };

    uevent_listener_.RegenerateUeventsForPath("/sys" + dm_path, dm_callback);

    if (!found) {

        LOG(INFO) << "device-mapper device not found in /sys, waiting for its uevent";

        LOG(INFO) << name << " device not found in /sys, waiting for its uevent";

        Timer t;

        uevent_listener_.Poll(dm_callback, 10s);

        LOG(INFO) << "Wait for device-mapper returned after " << t;

        LOG(INFO) << "Wait for " << name << " returned after " << t;

    }

    if (!found) {

        LOG(ERROR) << "device-mapper device not found after polling timeout";

        LOG(ERROR) << name << " device not found after polling timeout";

        return false;

    }

    return true;

init/block_dev_initializer.h

+3 −0
Original line number Diff line number Diff line
@@ -27,12 +27,15 @@ class BlockDevInitializer final { 
    BlockDevInitializer();



    bool InitDeviceMapper();

    bool InitDmUser();

    bool InitDevices(std::set<std::string> devices);

    bool InitDmDevice(const std::string& device);



  private:

    ListenerAction HandleUevent(const Uevent& uevent, std::set<std::string>* devices);



    bool InitMiscDevice(const std::string& name);



    std::unique_ptr<DeviceHandler> device_handler_;

    UeventListener uevent_listener_;

};