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Commit 491004bb authored by Juhyung Park's avatar Juhyung Park Committed by Jaegeuk Kim
Browse files

init: mount_handler: detect main block device more reliably 



Current code is not portable beyond SCSI devices (e.g., UFS).
For example, eMMC and NVMe devices fail due to their extra postfix.

Change its logic to rewind each character until "queue" directory appears.

Test: Confirm md0p1, sda20, nvme0n1p3, mmcblk0p3 are all handled well.
Change-Id: I585ccf2d4a72f6ef8ecb203acdd72a1e32d3e749
Signed-off-by: default avatarJuhyung Park <qkrwngud825@gmail.com>
parent 852111ee

init/mount_handler.cpp

+24 −10
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <unistd.h>



#include <algorithm>

#include <filesystem>

#include <string>

#include <utility>

#include <vector>
@@ -32,6 +33,7 @@ 
#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/properties.h>

#include <android-base/stringprintf.h>

#include <android-base/strings.h>

#include <fs_mgr.h>

#include <fstab/fstab.h>
@@ -39,6 +41,9 @@ 


#include "epoll.h"



using android::base::Basename;

using android::base::StringPrintf;



namespace android {

namespace init {
@@ -67,21 +72,30 @@ MountHandlerEntry ParseMount(const std::string& line) { 
    return MountHandlerEntry(fields[0], fields[1], fields[2]);

}



// return dm-4 or dm-8 for dm-4, sda for sda25, or mmcblk0 for mmcblk0p24

std::string GetRootDisk(std::string blockdev) {

    if (blockdev.find('/') != std::string::npos) return {};



    std::error_code ec;

    for (const auto& entry : std::filesystem::directory_iterator("/sys/block", ec)) {

        const std::string path = entry.path().string();

        if (std::filesystem::exists(StringPrintf("%s/%s", path.c_str(), blockdev.c_str()))) {

            return Basename(path);

        }

    }

    if (android::base::StartsWith(blockdev, "dm-")) return blockdev;

    return {};

}



void SetMountProperty(const MountHandlerEntry& entry, bool add) {

    static constexpr char devblock[] = "/dev/block/";

    if (!android::base::StartsWith(entry.blk_device, devblock)) return;

    auto target = entry.blk_device.substr(strlen(devblock));

    std::string value;

    if (add) {

        value = entry.blk_device.substr(strlen(devblock));

        if (android::base::StartsWith(value, "sd")) {

            // All sd partitions inherit their queue characteristics

            // from the whole device reference.  Strip partition number.

            auto it = std::find_if(value.begin(), value.end(), [](char c) { return isdigit(c); });

            if (it != value.end()) value.erase(it, value.end());

        }

        auto queue = "/sys/block/" + value + "/queue";

        value = GetRootDisk(target);



        struct stat sb;

        if (stat(queue.c_str(), &sb) || !S_ISDIR(sb.st_mode)) value = "";

        if (stat(entry.mount_point.c_str(), &sb) || !S_ISDIR(sb.st_mode)) value = "";

        // Clear the noise associated with loopback and APEX.

        if (android::base::StartsWith(value, "loop")) value = "";
@@ -98,7 +112,7 @@ void SetMountProperty(const MountHandlerEntry& entry, bool add) { 
    if (value.empty() && android::base::GetProperty(blk_mount_prop, "").empty()) return;

    android::base::SetProperty(blk_mount_prop, value);

    if (!value.empty()) {

        android::base::SetProperty(dev_mount_prop, entry.blk_device.substr(strlen(devblock)));

        android::base::SetProperty(dev_mount_prop, target);

    } else {

        android::base::SetProperty(dev_mount_prop, "");

    }