#include <stdio.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <unistd.h>
#include <sys/reboot.h>
#include "rkboot_control.h"

static unsigned int iavb_crc32_tab[] = {
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

/* Converts a 32-bit unsigned integer from host to big-endian byte order. */
unsigned int avb_htobe32(unsigned int in) {
    union {
        unsigned int word;
        unsigned char bytes[4];
    } ret;
    ret.bytes[0] = (in >> 24) & 0xff;
    ret.bytes[1] = (in >> 16) & 0xff;
    ret.bytes[2] = (in >> 8) & 0xff;
    ret.bytes[3] = in & 0xff;
    return ret.word;
}

/*
 *  A function that calculates the CRC-32 based on the table above is
 *  given below for documentation purposes. An equivalent implementation
 *  of this function that's actually used in the kernel can be found
 *  in sys/libkern.h, where it can be inlined.
 */
static unsigned int iavb_crc32(unsigned int crc_in, const unsigned char* buf, int size) {
    const unsigned char* p = buf;
    unsigned int crc;

    crc = crc_in ^ ~0U;
    while (size--)
    crc = iavb_crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
    return crc ^ ~0U;
}

unsigned int avb_crc32(const unsigned char* buf, size_t size) {
      return iavb_crc32(0, buf, size);
}

void AvbABData_update_crc(struct AvbABData *data)
{
    data->crc32 = avb_htobe32(avb_crc32((const unsigned char*)data, sizeof(struct AvbABData) - sizeof(unsigned int)));
}

/**
 * 从cmdline 获取从哪里引导
 * 返回值：
 *     0: a分区
 *     1: b分区
 */
int getCurrentSlot(){
    char cmdline[CMDLINE_LENGTH];
    int fd = open("/proc/cmdline", O_RDONLY);
    read(fd, (char*)cmdline, CMDLINE_LENGTH);
    close(fd);
    char *slot = strstr(cmdline, "androidboot.slot_suffix");
    if(slot != NULL){
        slot = strstr(slot, "=");
        if(slot != NULL){
            slot += 2;
            if((*slot) == 'a'){
                return 0;
            }else if((*slot) == 'b'){
                return 1;
            }
        }
    }
    printf("getCurrentSlot error.\n");
    return -1;
}


void display(struct AvbABData info){
    /*
    printf("magic = %s\n", info.magic);
    printf("version = %d\n", info.version);
    printf("last_boot = %d\n", info.last_boot);
    printf("use_a = %d\n", info.use_a);
    printf("use_b = %d\n", info.use_b);
    printf("current_boot = %d\n", info.current_boot);
    printf("crc32 = %d\n", info.crc32);
    */
    printf("magic = %s\n", info.magic);
    printf("version_major = %d.\n", info.version_major);
    printf("version_min = %d.\n", info.version_minor);
    for(int i = 0; i < 2; i++){
        printf("info.slot[%d]->priority = %d.\n", i, info.slots[i].priority);
        printf("info.slot[%d]->tries_remaining = %d.\n", i, info.slots[i].tries_remaining);
        printf("info.slot[%d]->successful_boot = %d.\n", i, info.slots[i].successful_boot);
    } 
    printf("last_boot = %d.\n", info.last_boot);
    printf("my crc32 = %x.\n", avb_crc32((const unsigned char*)&info, sizeof(struct AvbABData) - sizeof(unsigned int)));
    printf("crc32 = %x\n", info.crc32);
    printf("sizeof(struct AvbABData) = %ld\n", sizeof(struct AvbABData));
}

/**
 * 从misc 偏移2k处读取引导信息
 */
int readMisc(struct AvbABData* info){
    memset(info, 0, sizeof(struct AvbABData));

    int fd = open(MISC_PARTITION_NMAE, O_RDONLY);
    if(fd < 0){
        printf("open %s failed. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        return -1;
    }

    if(lseek(fd, MISC_OFFSET, SEEK_SET) == -1){
        printf("lseek %s error. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        close(fd);
        return -1;
    }

    if(read(fd, info, sizeof(struct AvbABData)) != sizeof(struct AvbABData)){
        printf("read failed, %s\n", strerror(errno));
        close(fd);
        return -1;
    }

    close(fd);
    return 0;
}

/**
 * 往misc 偏移2k处写入引导信息
 */
int writeMisc(struct AvbABData info){
    int fd = open(MISC_PARTITION_NMAE, O_WRONLY);
    if(fd < 0){
        printf("open %s failed.\n", MISC_PARTITION_NMAE);
        return -1;
    }

    if(lseek(fd, MISC_OFFSET, SEEK_SET) == -1){
        printf("lseek %s error. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        close(fd);
        return -1;
    }

    if(write(fd, &info, sizeof(struct AvbABData)) != sizeof(struct AvbABData)){
        printf("write failed, %s\n", strerror(errno));
        close(fd);
        return -1;
    }
    sync();
    close(fd);

    struct AvbABData data_check;
    if(readMisc(&data_check) == -1){
        return -1;
    }
    if(memcmp(&data_check, &info, sizeof(struct AvbABData)) != 0){
        printf("write error: memcmp \n");
        return -1;
    }

    return 0;
}

/**
 * 设置当前分区为可启动分区
 */
int setSlotSucceed(){
    int now_slot = getCurrentSlot();
    if(now_slot == -1){
        return -1;
    }
    struct AvbABData info;
    if(readMisc(&info) == -1){
        return -1;
    }
    
#ifdef SUCCESSFUL_BOOT
    info.slots[now_slot].tries_remaining = 0;
    info.slots[now_slot].successful_boot = 1;
#endif
#ifdef RETRY_BOOT
    info.slots[now_slot].tries_remaining = AVB_AB_MAX_TRIES_REMAINING;
#endif
    info.last_boot = now_slot;

    AvbABData_update_crc(&info);

    if(writeMisc(info) != 0){
        return -1;
    }
    return 0;
}

/**
 * 设置升级分区, 即另外一个分区优先级最高
 */
int setSlotActivity(){
    int now_slot = getCurrentSlot();
    if(now_slot == -1){
        return -1;
    }
    struct AvbABData info;

    if(readMisc(&info) == -1){
        return -1;
    }

    info.slots[now_slot].priority = AVB_AB_MAX_PRIORITY - 1;
    info.slots[1 - now_slot].priority = AVB_AB_MAX_PRIORITY;
    info.slots[1 - now_slot].tries_remaining = AVB_AB_MAX_TRIES_REMAINING;
#ifdef SUCCESSFUL_BOOT
    info.slots[1 - now_slot].successful_boot = 0;
#endif

    AvbABData_update_crc(&info);

    if(writeMisc(info) != 0){
        return -1;
    }
    return 0;
}


/**
 * 从misc 偏移4k处读取命令
 */
static int readMiscCmd(char *cmdline, int length){
    memset(cmdline, 0, strlen(cmdline));
    int fd = open(MISC_PARTITION_NMAE, O_RDONLY);
    if(fd < 0){
        printf("open %s failed. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        return -1;
    }
    if(lseek(fd, MISC_OFFSET_CMDLINE, SEEK_SET) == -1){
        printf("lseek %s error. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        close(fd);
        return -1;
    }

    if(read(fd, cmdline, length) != length){
        printf("read failed, %s\n", strerror(errno));
        close(fd);
        return -1;
    }
    close(fd);
    return 0;
}

/**
 * 往misc 偏移4k处写入命令
 */
static int writeMiscCmd(char *cmdline){
    int fd = open(MISC_PARTITION_NMAE, O_WRONLY);
    if(fd < 0){
        printf("open %s failed.\n", MISC_PARTITION_NMAE);
        return -1;
    }

    if(lseek(fd, MISC_OFFSET_CMDLINE, SEEK_SET) == -1){
        printf("lseek %s error. %s\n", MISC_PARTITION_NMAE, strerror(errno));
        close(fd);
        return -1;
    }

    if(write(fd, cmdline, strlen(cmdline)) != strlen(cmdline)){
        printf("write failed, %s\n", strerror(errno));
        close(fd);
        return -1;
    }
    sync();
    close(fd);

    char tmp[256];
    if(readMiscCmd(tmp, strlen(cmdline)) == -1){
        return -1;
    }
    if(memcmp(tmp, cmdline, strlen(cmdline)) != 0){
        printf("write error: memcmp \n");
        return -1;
    }

    return 0;
}

bool wipe_userdata(bool auto_reboot){
    if(writeMiscCmd(CMD_WIPE_USERDATA) != 0){
        return false;
    }

    if(auto_reboot) {
        printf("auto reboot, %s.\n", CMD_WIPE_USERDATA);
        sleep(1);
        reboot(RB_AUTOBOOT);
    }
    return true;
}