#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define NETPERF_CMD     "netperf"
#define NETPERF_PATH    "/usr/local/bin/" NETPERF_CMD

struct netperf_child {
        int             pipes[2];
};

static void
usage(const char *cmd)
{
        fprintf(stderr, "%s -H host [-l len_s] [-i instances]\n", cmd);
        exit(1);
}

int
main(int argc, char *argv[])
{
        struct netperf_child *instance;
        char len_str[32];
        char *args[32];
        const char *host;
        volatile int ninst;
        int len, ninst_done;
        int opt, i, null_fd;
        double result;

        host = NULL;
        ninst = 2;
        len = 10;

        while ((opt = getopt(argc, argv, "i:H:l:")) != -1) {
                switch (opt) {
                case 'i':
                        ninst = strtoul(optarg, NULL, 10);
                        break;

                case 'H':
                        host = optarg;
                        break;

                case 'l':
                        len = strtoul(optarg, NULL, 10);
                        break;

                default:
                        usage(argv[0]);
                }
        }
        if (ninst <= 0 || host == NULL || len <= 0)
                usage(argv[0]);

        snprintf(len_str, sizeof(len_str), "%d", len);

        i = 0;
        args[i++] = __DECONST(char *, NETPERF_CMD);
        args[i++] = __DECONST(char *, "-P0");
        args[i++] = __DECONST(char *, "-H");
        args[i++] = __DECONST(char *, host);
        args[i++] = __DECONST(char *, "-l");
        args[i++] = __DECONST(char *, len_str);
        args[i++] = __DECONST(char *, "-t");
        args[i++] = __DECONST(char *, "TCP_CC");
        args[i] = NULL;

        instance = calloc(ninst, sizeof(struct netperf_child));
        if (instance == NULL)
                err(1, "calloc failed");

        null_fd = open("/dev/null", O_RDWR);
        if (null_fd < 0)
                err(1, "open null failed");

        for (i = 0; i < ninst; ++i) {
                if (pipe(instance[i].pipes) < 0)
                        err(1, "pipe %dth failed", i);
        }

        for (i = 0; i < ninst; ++i) {
                pid_t pid;

                pid = vfork();
                if (pid == 0) {
                        int ret;

                        dup2(instance[i].pipes[1], STDOUT_FILENO);
                        dup2(null_fd, STDERR_FILENO);
                        ret = execv(NETPERF_PATH, args);
                        if (ret < 0) {
                                warn("execv %d failed", i);
                                _exit(1);
                        }
                        /* Never reached */
                        abort();
                } else if (pid < 0) {
                        err(1, "vfork %d failed", i);
                }
                close(instance[i].pipes[1]);
                instance[i].pipes[1] = -1;
        }

        ninst_done = 0;
        while (ninst_done < ninst) {
                pid_t pid;

                pid = waitpid(-1, NULL, 0);
                if (pid < 0)
                        err(1, "waitpid failed");
                ++ninst_done;
        }

        result = 0.0;
        for (i = 0; i < ninst; ++i) {
                char line[128];
                FILE *fp;

                fp = fdopen(instance[i].pipes[0], "r");
                if (fp == NULL)
                        err(1, "fdopen %dth failed\n", i);

                while (fgets(line, sizeof(line), fp) != NULL) {
                        int n, arg1, arg2, arg3, arg4;
                        double res, arg5;

                        n = sscanf(line, "%d%d%d%d%lf%lf",
                            &arg1, &arg2, &arg3, &arg4, &arg5, &res);
                        if (n == 6) {
                                result += res;
                                break;
                        }
                }
                fclose(fp);
        }
        printf("TCP_CC %.2f conns/s\n", result);

        exit(0);
}