/* Test groups of 20 processes spraying to 20 receivers */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <semaphore.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/poll.h>
#include "interbench.h"

#define DATASIZE 100
#define LOOPS   100
#define NUM_FDS 20

static inline void barf(const char *msg)
{
        terminal_error(msg);
}

static void fdpair(int fds[2])
{
        if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) == -1)
                barf("Creating fdpair");
}

/* Block until we're ready to go */
static void ready(int ready_out, int wakefd)
{
        char dummy;
        struct pollfd pollfd = { .fd = wakefd, .events = POLLIN };

        /* Tell them we're ready. */
        if (write(ready_out, &dummy, 1) != 1)
                barf("CLIENT: ready write");

        /* Wait for "GO" signal */
        if (poll(&pollfd, 1, -1) != 1)
                barf("poll");
}

/* Sender sprays LOOPS messages down each file descriptor */
static void sender(int out_fd[NUM_FDS],
                   int ready_out,
                   int wakefd)
{
        char data[DATASIZE];
        unsigned int i, j;

        ready(ready_out, wakefd);

        /* Now pump to every receiver. */
        for (i = 0; i < LOOPS; i++) {
                for (j = 0; j < NUM_FDS; j++) {
                        int ret;
                        unsigned long done = 0;

                again:
                        ret = write(out_fd[j], data + done, sizeof(data)-done);
                        if (ret < 0)
                                barf("SENDER: write");
                        done += ret;
                        if (done < sizeof(data))
                                goto again;
                }
        }
}

/* One receiver per fd */
static void receiver(unsigned int num_packets,
                     int in_fd,
                     int ready_out,
                     int wakefd)
{
        unsigned int i;

        /* Wait for start... */
        ready(ready_out, wakefd);

        /* Receive them all */
        for (i = 0; i < num_packets; i++) {
                char data[DATASIZE];
                int ret, done = 0;

        again:
                ret = Read(in_fd, data + done, DATASIZE - done);
                done += ret;
                if (done < DATASIZE)
                        goto again;
        }
}

/* One group of senders and receivers */
static unsigned int group(int ready_out,
                          int wakefd)
{
        unsigned int i;
        int out_fds[NUM_FDS];

        for (i = 0; i < NUM_FDS; i++) {
                int fds[2];

                /* Create the pipe between client and server */
                fdpair(fds);

                /* Fork the receiver. */
                switch (fork()) {
                case -1: barf("fork()");
                case 0:
                        close(fds[1]);
                        receiver(NUM_FDS*LOOPS, fds[0], ready_out, wakefd);
                        exit(0);
                }

                out_fds[i] = fds[1];
                close(fds[0]);
        }

        /* Now we have all the fds, fork the senders */
        for (i = 0; i < NUM_FDS; i++) {
                switch (fork()) {
                case -1: barf("fork()");
                case 0:
                        sender(out_fds, ready_out, wakefd);
                        exit(0);
                }
        }

        /* Close the fds we have left */
        for (i = 0; i < NUM_FDS; i++)
                close(out_fds[i]);

        /* Return number of children to reap */
        return NUM_FDS * 2;
}

void *hackbench_thread(void *t)
{
        unsigned int i, num_groups, total_children;
        int readyfds[2], wakefds[2];
        char dummy;

        num_groups = 50;
        t = NULL;

        fdpair(readyfds);
        fdpair(wakefds);
        
        while (1) {
                total_children = 0;
                for (i = 0; i < num_groups; i++)
                        total_children += group(readyfds[1], wakefds[0]);
        
                /* Wait for everyone to be ready */
                for (i = 0; i < total_children; i++)
                        if (Read(readyfds[0], &dummy, 1) != 1)
                                barf("Reading for readyfds");
        
                /* Kick them off */
                if (write(wakefds[1], &dummy, 1) != 1)
                        barf("Writing to start them");
        
                /* Reap them all */
                for (i = 0; i < total_children; i++) {
                        int status;
                        wait(&status);
                        if (!WIFEXITED(status))
                                exit(1);
                }
                if (!trywait_sem(&hackthread.sem.stop))
                        break;
        }

        post_sem(&hackthread.sem.complete);
        return NULL;
}