XCTF community re novice area title open-source

open-source

Subject to the source code, so just look at the source code on the line:

#include <stdio.h>
#include <string.h>

int main(int argc, char *argv[]) {
    if (argc != 4) {
    	printf("what?\n");
    	exit(1);
    }

    unsigned int first = atoi(argv[1]);
    if (first != 0xcafe) {
    	printf("you are wrong, sorry.\n");
    	exit(2);
    }

    unsigned int second = atoi(argv[2]);
    if (second % 5 == 3 || second % 17 != 8) {
    	printf("ha, you won't get it!\n");
    	exit(3);
    }

    if (strcmp("h4cky0u", argv[3])) {
    	printf("so close, dude!\n");
    	exit(4);
    }

    printf("Brr wrrr grr\n");

    unsigned int hash = first * 31337 + (second % 17) * 11 + strlen(argv[3]) - 1615810207;

    printf("Get your key: ");
    printf("%x\n", hash);
    return 0;
}

Based on the subject, there are several parts, the first is the first, which has a function for atoi ascii code is converted to type int, and the last of which if it is more strcmp function, when str1 = str2, return value 0, str1> str2, the return value is 1, str1 <str2 time, returns a value of -1;
then according to the last: unsigned int hash = first * 31337 + (second% 17) * 11 + strlen (argv [3 ]) --1,615,810,207;
write a py to operation on the line, the result of the operation into hexadecimal, binary conversion on py: look:

a=int('0xcafe',16)
print(a)
flag=0xcafe*31337+8*11+7-1615810207
print(hex(flag))

Draw flag: 0xc0ffee