/*

 * Copyright (C) 2023 Huawei Device Co., Ltd.

 * 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 <cstdlib>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <fcntl.h>

#include <sys/mount.h>

#include <securec.h>

#include <sys/wait.h>



#include "log.h"

#include "mount.h"



using namespace Hdc;



bool FindMountDeviceByPath(const char *toQuery, char *dev)

{

    int ret = false;

    int len = BUF_SIZE_DEFAULT2;

    char buf[BUF_SIZE_DEFAULT2];



    FILE *fp = fopen("/proc/mounts", "r");

    if (fp == nullptr) {

        WRITE_LOG(LOG_FATAL, "fopen /proc/mounts error:%d", errno);

        return false;

    }



    while (fgets(buf, len, fp) != nullptr) {

        char dir[BUF_SIZE_SMALL] = "";

        int freq;

        int passnno;

        int res = 0;

        // clang-format off

        res = sscanf_s(buf, "%255s %255s %*s %*s %d %d\n", dev, BUF_SIZE_SMALL - 1,

                       dir, BUF_SIZE_SMALL - 1, &freq, &passnno);

        // clang-format on

        dev[BUF_SIZE_SMALL - 1] = '\0';

        dir[BUF_SIZE_SMALL - 1] = '\0';

        if (res == 4 && (strcmp(toQuery, dir) == 0)) {  // 4 : The correct number of parameters

            WRITE_LOG(LOG_DEBUG, "FindMountDeviceByPath dev:%s dir:%s", dev, dir);

            ret = true;

            break;

        }

    }

    int rc = fclose(fp);

    if (rc != 0) {

        WRITE_LOG(LOG_WARN, "fclose rc:%d error:%d", rc, errno);

    }

    if (!ret) {

        WRITE_LOG(LOG_FATAL, "FindMountDeviceByPath not found %s", toQuery);

    }

    return ret;

}



bool RemountPartition(const char *dir)

{

    int fd;

    int off = 0;

    int ret = 0;

    char dev[BUF_SIZE_SMALL] = "";



    if (!FindMountDeviceByPath(dir, dev) || strlen(dev) < 4) {  // 4 : file count

        WRITE_LOG(LOG_FATAL, "FindMountDeviceByPath dir:%s failed", dir);

        return false;

    }



    if ((fd = open(dev, O_RDONLY | O_CLOEXEC)) < 0) {

        WRITE_LOG(LOG_FATAL, "open dev:%s failed, error:%d", dev, errno);

        return false;

    }

    ioctl(fd, BLKROSET, &off);

    close(fd);



    ret = mount(dev, dir, "none", MS_REMOUNT, nullptr);

    if (ret < 0) {

        WRITE_LOG(LOG_FATAL, "mount %s failed, reason is %s", dev, strerror(errno));

        return false;

    }

    return true;

}



bool RemountDevice()

{

    if (getuid() != 0) {

        return false;

    }

    struct stat info;

    if (!lstat("/vendor", &info) && (info.st_mode & S_IFMT) == S_IFDIR) {

        if (!RemountPartition("/vendor")) {

            WRITE_LOG(LOG_FATAL, "Mount failed /vendor (via mount)");

        }

    }

    if (!lstat("/system", &info) && (info.st_mode & S_IFMT) == S_IFDIR) {

        if (!RemountPartition("/")) {

            WRITE_LOG(LOG_FATAL, "Mount failed /system (via mount)");

        }

    }

    

    int exitStatus = system("/bin/remount");

    if (exitStatus == -1) {

        WRITE_LOG(LOG_FATAL, "Failed to execute /bin/remount: %s", strerror(errno));

        return false;

    } else if (WIFEXITED(exitStatus) && WEXITSTATUS(exitStatus) != 0) {

        WRITE_LOG(LOG_FATAL, "Remount failed with exit code: %d", WEXITSTATUS(exitStatus));

        return false;

    }

    return true;

}