#include <stdio.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <signal.h>

int pid;

void sig_handler(int sig) {
    if (pid > 0) {
        kill(pid, sig);
    }
}

int wait_exit() {
    int status;
    struct rusage ru;

    if (wait4(pid, &status, 0, &ru) == -1) {
        printf("wait child exit fail!\n");
        return -1;
    }

    printf("\n");
    printf("exit code: %d\n", status);
    printf("sys time used: %d  ms\n",
        ru.ru_stime.tv_sec * 1000 + ru.ru_stime.tv_usec / 1000);
    printf("usr time used: %d ms\n",
        ru.ru_utime.tv_sec * 1000 + ru.ru_utime.tv_usec / 1000);
    printf("maximum resident set size: %ld kb\n", ru.ru_maxrss);
    printf("shared text segment memory: %d kb\n", ru.ru_ixrss);
    printf("data segment memory: %d kb\n", ru.ru_idrss);
    printf("stack memory: %d kb\n", ru.ru_isrss);
    printf("soft page faults: %d kb\n", ru.ru_minflt);
    printf("hard page faults: %d kb\n", ru.ru_majflt);
    printf("file input operations: %d\n", ru.ru_inblock);
    printf("file output operations: %d\n", ru.ru_oublock);
    printf("voluntary context switches: %d\n", ru.ru_nvcsw);

    return 0;
}

int run(char* const *cmd) {
    pid = vfork();

    if (pid == -1) {
        printf("vfork fail!\n");
        return -1;
    } else if (pid == 0) {
        execvp(cmd[0], cmd);
        perror("execlp fail!");
        _exit(-1);
    } else {
        signal(SIGINT, sig_handler);
        signal(SIGTERM, sig_handler);
        signal(SIGHUP, sig_handler);
        return wait_exit(pid);
    }
}

int main(int argc, char const *argv[]) {
    pid = 0;
    if (argc < 2) {
        printf("usage: %s cmd\n", argv[0]);
        return -1;
    }

    return run((char* const*)(argv+1));
}