CS:APP makecookie source code (reveng'd from binary)

makecookie.c

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

int hash(const char *s) {
    int ret = 0;
    for (; *s; s++) {
        ret = 103 * ret + *s;
    }
    return ret;
}

int check(int v) {
    if (v >> 28) {
        int shift = 0;
        while ((char)(v >> shift) != '\n') {
            shift += CHAR_BIT;
            if (shift == sizeof(int) * CHAR_BIT)
                return 1;
        }
    }
    return 0;
}

int gencookie(const char *s) {
    srand(hash(s));
    int ret;
    do {
        ret = rand();
    } while (!check(ret));
    return ret;
}

int main(int argc, char **argv) {
    if (argc < 2)
        return 0;
    for (int i = 1; i < argc; i++)
        printf("0x%x\n", gencookie(argv[i]));
    return 0;
}