Merge "updater: Add a function to check first block"

#include "applypatch/applypatch.h"

#include "edify/expr.h"

#include "install.h"

#include "mincrypt/sha.h"

#include "minzip/Hash.h"

#include "print_sha1.h"

    return StringValue(strdup(print_sha1(digest).c_str()));

}

// This function checks if a device has been remounted R/W prior to an incremental

// OTA update. This is an common cause of update abortion. The function reads the

// 1st block of each partition and check for mounting time/count. It return string "t"

// if executes successfully and an empty string otherwise.

Value* CheckFirstBlockFn(const char* name, State* state, int argc, Expr* argv[]) {

    Value* arg_filename;

    if (ReadValueArgs(state, argv, 1, &arg_filename) < 0) {

        return nullptr;

    }

    std::unique_ptr<Value, decltype(&FreeValue)> filename(arg_filename, FreeValue);

    if (filename->type != VAL_STRING) {

        ErrorAbort(state, "filename argument to %s must be string", name);

        return StringValue(strdup(""));

    }

    int fd = open(arg_filename->data, O_RDONLY);

    unique_fd fd_holder(fd);

    if (fd == -1) {

        ErrorAbort(state, "open \"%s\" failed: %s", arg_filename->data, strerror(errno));

        return StringValue(strdup(""));

    }

    RangeSet blk0 {1 /*count*/, 1/*size*/, std::vector<size_t> {0, 1}/*position*/};

    std::vector<uint8_t> block0_buffer(BLOCKSIZE);

    if (ReadBlocks(blk0, block0_buffer, fd) == -1) {

        ErrorAbort(state, "failed to read %s: %s", arg_filename->data,

                strerror(errno));

        return StringValue(strdup(""));

    }

    // https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout

    // Super block starts from block 0, offset 0x400

    //   0x2C: len32 Mount time

    //   0x30: len32 Write time

    //   0x34: len16 Number of mounts since the last fsck

    //   0x38: len16 Magic signature 0xEF53

    time_t mount_time = *reinterpret_cast<uint32_t*>(&block0_buffer[0x400+0x2C]);

    uint16_t mount_count = *reinterpret_cast<uint16_t*>(&block0_buffer[0x400+0x34]);

    if (mount_count > 0) {

        uiPrintf(state, "Device was remounted R/W %d times\n", mount_count);

        uiPrintf(state, "Last remount happened on %s", ctime(&mount_time));

    }

    return StringValue(strdup("t"));

}

Value* BlockImageRecoverFn(const char* name, State* state, int argc, Expr* argv[]) {

    Value* arg_filename;

    Value* arg_ranges;

    RegisterFunction("block_image_verify", BlockImageVerifyFn);

    RegisterFunction("block_image_update", BlockImageUpdateFn);

    RegisterFunction("block_image_recover", BlockImageRecoverFn);

    RegisterFunction("check_first_block", CheckFirstBlockFn);

    RegisterFunction("range_sha1", RangeSha1Fn);

}

void RegisterInstallFunctions();

// uiPrintf function prints msg to screen as well as logs

void uiPrintf(State* state, const char* format, ...);

static int make_parents(char* name);

#endif