tcp-non-blocking-libuv-echo-server.c

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

uv_loop_t *loop;

void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf)
{
    buf->base = (char *)malloc(suggested_size);
    buf->len = suggested_size;
}

void echo_write(uv_write_t *req, int status)
{
    if (status)
    {
        fprintf(stderr, "Write error %s\n", uv_strerror(status));
    }
    free(req);
}

void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf)
{
    if (nread < 0)
    {
        if (nread != UV_EOF)
        {
            fprintf(stderr, "Read error %s\n", uv_err_name(nread));
            uv_close((uv_handle_t *)client, NULL);
        }
    }
    else if (nread > 0)
    {
        uv_write_t *req = (uv_write_t *)malloc(sizeof(uv_write_t));
        uv_buf_t wrbuf = uv_buf_init(buf->base, nread);
        uv_write(req, client, &wrbuf, 1, echo_write);
    }

    if (buf->base)
    {
        free(buf->base);
    }
}

void on_accept(uv_stream_t *server, int status)
{
    if (status < 0)
    {
        fprintf(stderr, "New connection error %s\n", uv_strerror(status));
        return;
    }

    uv_tcp_t *client = (uv_tcp_t *)malloc(sizeof(uv_tcp_t));
    uv_tcp_init(loop, client);
    if (uv_accept(server, (uv_stream_t *)client) == 0)
    {
        uv_read_start((uv_stream_t *)client, alloc_buffer, echo_read);
    }
    else
    {
        uv_close((uv_handle_t *)client, NULL);
    }
}

int main()
{
    loop = uv_default_loop();

    uv_tcp_t server;
    uv_tcp_init(loop, &server);

    struct sockaddr_in addr;
    uv_ip4_addr("0.0.0.0", 7000, &addr);

    uv_tcp_bind(&server, (const struct sockaddr *)&addr, 0);
    int r = uv_listen((uv_stream_t *)&server, 128, on_accept);
    if (r)
    {
        fprintf(stderr, "Listen error %s\n", uv_strerror(r));
        return 1;
    }
    return uv_run(loop, UV_RUN_DEFAULT);
}