1#include <stdio.h>
2#include <stdlib.h>
3#include <string.h>
4#include <uv.h>
5
6#define DEFAULT_PORT 7000
7#define DEFAULT_BACKLOG 128
8
9uv_loop_t *loop;
10struct sockaddr_in addr;
11
12typedef struct {
13    uv_write_t req;
14    uv_buf_t buf;
15} write_req_t;
16
17void free_write_req(uv_write_t *req) {
18    write_req_t *wr = (write_req_t*) req;
19    free(wr->buf.base);
20    free(wr);
21}
22
23void alloc_buffer(uv_handle_t *handle, size_t suggested_size, uv_buf_t *buf) {
24    buf->base = (char*) malloc(suggested_size);
25    buf->len = suggested_size;
26}
27
28void on_close(uv_handle_t* handle) {
29    free(handle);
30}
31
32void echo_write(uv_write_t *req, int status) {
33    if (status) {
34        fprintf(stderr, "Write error %s\n", uv_strerror(status));
35    }
36    free_write_req(req);
37}
38
39void echo_read(uv_stream_t *client, ssize_t nread, const uv_buf_t *buf) {
40    if (nread > 0) {
41        write_req_t *req = (write_req_t*) malloc(sizeof(write_req_t));
42        req->buf = uv_buf_init(buf->base, nread);
43        uv_write((uv_write_t*) req, client, &req->buf, 1, echo_write);
44        return;
45    }
46    if (nread < 0) {
47        if (nread != UV_EOF)
48            fprintf(stderr, "Read error %s\n", uv_err_name(nread));
49        uv_close((uv_handle_t*) client, on_close);
50    }
51
52    free(buf->base);
53}
54
55void on_new_connection(uv_stream_t *server, int status) {
56    if (status < 0) {
57        fprintf(stderr, "New connection error %s\n", uv_strerror(status));
58        // error!
59        return;
60    }
61
62    uv_tcp_t *client = (uv_tcp_t*) malloc(sizeof(uv_tcp_t));
63    uv_tcp_init(loop, client);
64    if (uv_accept(server, (uv_stream_t*) client) == 0) {
65        uv_read_start((uv_stream_t*) client, alloc_buffer, echo_read);
66    }
67    else {
68        uv_close((uv_handle_t*) client, on_close);
69    }
70}
71
72int main() {
73    loop = uv_default_loop();
74
75    uv_tcp_t server;
76    uv_tcp_init(loop, &server);
77
78    uv_ip4_addr("0.0.0.0", DEFAULT_PORT, &addr);
79
80    uv_tcp_bind(&server, (const struct sockaddr*)&addr, 0);
81    int r = uv_listen((uv_stream_t*) &server, DEFAULT_BACKLOG, on_new_connection);
82    if (r) {
83        fprintf(stderr, "Listen error %s\n", uv_strerror(r));
84        return 1;
85    }
86    return uv_run(loop, UV_RUN_DEFAULT);
87}
88