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

static void
help(void)
{
    printf("usage: ./checkenv <ENV>:<...>:<...>\n");
    printf("[-h]    Display this help menu\n");
}

static int
check_envs(const char *envlist)
{
    char *p, *tok;
    char *env;

    p = strdup(envlist);
    if (p == NULL) {
        printf("fatal: out of memory\n");
        return -1;
    }

    tok = strtok(p, ":");
    while (tok != NULL) {
        if ((env = getenv(tok)) == NULL) {
            printf("env '%s' not set\n", tok);
            return -1;
        }
        tok = strtok(NULL, ":");
    }

    return 0;
}

int
main(int argc, char **argv)
{
    int opt;
    char *envlist;
    int error;

    if (argc < 2) {
        printf("fatal: too few arguments\n");
        help();
        return -1;
    }

    while ((opt = getopt(argc, argv, "h")) != -1) {
        switch (opt) {
        case 'h':
            help();
            return -1;
        }
    }

    while (optind < argc) {
        envlist = argv[optind++];
        if ((error = check_envs(envlist)) < 0) {
            return error;
        }
    }

    return 0;
}