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tevent: Add echo server sample code
This is under a deliberately permissive license. I would like people to start using libtevent and tevent_req (LGPL) without any worries about where to start from. Signed-off-by: Volker Lendecke <vl@samba.org> Reviewed-by: Amitay Isaacs <amitay@gmail.com> Autobuild-User(master): Amitay Isaacs <amitay@samba.org> Autobuild-Date(master): Mon Aug 5 04:07:58 CEST 2013 on sn-devel-104
This commit is contained in:
Volker Lendecke
Amitay Isaacs
parent
b35a27b779
commit
cae48e9a36
664
lib/tevent/echo_server.c
Normal file
664
lib/tevent/echo_server.c
Normal file
@ -0,0 +1,664 @@
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/**
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** NOTE! The following liberal license applies to this sample file only.
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** This does NOT imply that all of Samba is released under this license.
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**
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** This file is meant as a starting point for libtevent users to be used
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** in any program linking against the LGPL licensed libtevent.
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**/
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/*
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* This file is being made available by the Samba Team under the following
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* license:
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*
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* Permission to use, copy, modify, and distribute this sample file for any
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* purpose is hereby granted without fee.
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*
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* This work is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <netinet/in.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <errno.h>
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#include <unistd.h>
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#include "tevent.h"
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#include "talloc.h"
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/**
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* @brief Helper function to get a useful unix error from tevent_req
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*/
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static bool tevent_req_is_unix_error(struct tevent_req *req, int *perrno)
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{
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enum tevent_req_state state;
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uint64_t err;
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if (!tevent_req_is_error(req, &state, &err)) {
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return false;
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}
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switch (state) {
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case TEVENT_REQ_TIMED_OUT:
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*perrno = ETIMEDOUT;
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break;
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case TEVENT_REQ_NO_MEMORY:
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*perrno = ENOMEM;
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break;
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case TEVENT_REQ_USER_ERROR:
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*perrno = err;
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break;
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default:
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*perrno = EINVAL;
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break;
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}
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return true;
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}
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/**
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* @brief Wrapper around accept(2)
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*/
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struct accept_state {
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struct tevent_fd *fde;
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int listen_sock;
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socklen_t addrlen;
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struct sockaddr addr;
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int sock;
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};
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static void accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data);
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static struct tevent_req *accept_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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int listen_sock)
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{
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struct tevent_req *req;
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struct accept_state *state;
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req = tevent_req_create(mem_ctx, &state, struct accept_state);
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if (req == NULL) {
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return NULL;
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}
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state->listen_sock = listen_sock;
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state->fde = tevent_add_fd(ev, state, listen_sock, TEVENT_FD_READ,
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accept_handler, req);
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if (tevent_req_nomem(state->fde, req)) {
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return tevent_req_post(req, ev);
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}
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return req;
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}
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static void accept_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data)
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{
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struct tevent_req *req = talloc_get_type_abort(
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private_data, struct tevent_req);
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struct accept_state *state = tevent_req_data(req, struct accept_state);
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int ret;
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TALLOC_FREE(state->fde);
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if ((flags & TEVENT_FD_READ) == 0) {
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tevent_req_error(req, EIO);
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return;
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}
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state->addrlen = sizeof(state->addr);
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ret = accept(state->listen_sock, &state->addr, &state->addrlen);
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if (ret == -1) {
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tevent_req_error(req, errno);
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return;
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}
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state->sock = ret;
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tevent_req_done(req);
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}
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static int accept_recv(struct tevent_req *req, struct sockaddr *paddr,
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socklen_t *paddrlen, int *perr)
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{
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struct accept_state *state = tevent_req_data(req, struct accept_state);
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int err;
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if (tevent_req_is_unix_error(req, &err)) {
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if (perr != NULL) {
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*perr = err;
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}
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return -1;
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}
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if (paddr != NULL) {
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*paddr = state->addr;
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}
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if (paddrlen != NULL) {
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*paddrlen = state->addrlen;
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}
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return state->sock;
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}
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/**
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* @brief Wrapper around read(2)
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*/
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struct read_state {
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struct tevent_fd *fde;
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int fd;
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void *buf;
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size_t count;
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ssize_t nread;
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};
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static void read_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data);
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static struct tevent_req *read_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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int fd, void *buf, size_t count)
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{
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struct tevent_req *req;
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struct read_state *state;
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req = tevent_req_create(mem_ctx, &state, struct read_state);
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if (req == NULL) {
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return NULL;
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}
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state->fd = fd;
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state->buf = buf;
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state->count = count;
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state->fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ,
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read_handler, req);
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if (tevent_req_nomem(state->fde, req)) {
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return tevent_req_post(req, ev);
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}
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return req;
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}
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static void read_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data)
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{
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struct tevent_req *req = talloc_get_type_abort(
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private_data, struct tevent_req);
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struct read_state *state = tevent_req_data(req, struct read_state);
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ssize_t ret;
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TALLOC_FREE(state->fde);
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if ((flags & TEVENT_FD_READ) == 0) {
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tevent_req_error(req, EIO);
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return;
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}
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ret = read(state->fd, state->buf, state->count);
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if (ret == -1) {
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tevent_req_error(req, errno);
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return;
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}
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state->nread = ret;
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tevent_req_done(req);
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}
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static ssize_t read_recv(struct tevent_req *req, int *perr)
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{
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struct read_state *state = tevent_req_data(req, struct read_state);
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int err;
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if (tevent_req_is_unix_error(req, &err)) {
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if (perr != NULL) {
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*perr = err;
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}
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return -1;
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}
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return state->nread;
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}
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/**
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* @brief Wrapper around write(2)
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*/
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struct write_state {
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struct tevent_fd *fde;
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int fd;
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const void *buf;
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size_t count;
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ssize_t nwritten;
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};
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static void write_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data);
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static struct tevent_req *write_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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int fd, const void *buf, size_t count)
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{
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struct tevent_req *req;
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struct write_state *state;
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req = tevent_req_create(mem_ctx, &state, struct write_state);
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if (req == NULL) {
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return NULL;
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}
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state->fd = fd;
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state->buf = buf;
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state->count = count;
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state->fde = tevent_add_fd(ev, state, fd, TEVENT_FD_WRITE,
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write_handler, req);
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if (tevent_req_nomem(state->fde, req)) {
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return tevent_req_post(req, ev);
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}
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return req;
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}
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static void write_handler(struct tevent_context *ev, struct tevent_fd *fde,
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uint16_t flags, void *private_data)
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{
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struct tevent_req *req = talloc_get_type_abort(
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private_data, struct tevent_req);
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struct write_state *state = tevent_req_data(req, struct write_state);
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ssize_t ret;
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TALLOC_FREE(state->fde);
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if ((flags & TEVENT_FD_WRITE) == 0) {
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tevent_req_error(req, EIO);
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return;
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}
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ret = write(state->fd, state->buf, state->count);
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if (ret == -1) {
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tevent_req_error(req, errno);
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return;
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}
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state->nwritten = ret;
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tevent_req_done(req);
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}
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static ssize_t write_recv(struct tevent_req *req, int *perr)
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{
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struct write_state *state = tevent_req_data(req, struct write_state);
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int err;
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if (tevent_req_is_unix_error(req, &err)) {
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if (perr != NULL) {
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*perr = err;
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}
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return -1;
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}
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return state->nwritten;
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}
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/**
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* @brief Wrapper function that deals with short writes
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*/
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struct writeall_state {
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struct tevent_context *ev;
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int fd;
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const void *buf;
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size_t count;
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size_t nwritten;
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};
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static void writeall_done(struct tevent_req *subreq);
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static struct tevent_req *writeall_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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int fd, const void *buf, size_t count)
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{
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struct tevent_req *req, *subreq;
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struct writeall_state *state;
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req = tevent_req_create(mem_ctx, &state, struct writeall_state);
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if (req == NULL) {
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return NULL;
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}
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state->ev = ev;
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state->fd = fd;
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state->buf = buf;
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state->count = count;
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state->nwritten = 0;
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subreq = write_send(state, state->ev, state->fd,
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((char *)state->buf)+state->nwritten,
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state->count - state->nwritten);
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if (tevent_req_nomem(subreq, req)) {
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return tevent_req_post(req, ev);
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}
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tevent_req_set_callback(subreq, writeall_done, req);
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return req;
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}
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static void writeall_done(struct tevent_req *subreq)
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{
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struct tevent_req *req = tevent_req_callback_data(
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subreq, struct tevent_req);
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struct writeall_state *state = tevent_req_data(
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req, struct writeall_state);
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ssize_t nwritten;
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int err = 0;
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nwritten = write_recv(subreq, &err);
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TALLOC_FREE(subreq);
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if (nwritten == -1) {
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tevent_req_error(req, err);
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return;
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}
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state->nwritten += nwritten;
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if (state->nwritten < state->count) {
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subreq = write_send(state, state->ev, state->fd,
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((char *)state->buf)+state->nwritten,
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state->count - state->nwritten);
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if (tevent_req_nomem(subreq, req)) {
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return;
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}
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tevent_req_set_callback(subreq, writeall_done, req);
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return;
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}
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tevent_req_done(req);
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}
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static ssize_t writeall_recv(struct tevent_req *req, int *perr)
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{
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struct writeall_state *state = tevent_req_data(
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req, struct writeall_state);
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int err;
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if (tevent_req_is_unix_error(req, &err)) {
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if (perr != NULL) {
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*perr = err;
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}
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return -1;
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}
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return state->nwritten;
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}
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/**
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* @brief Async echo handler code dealing with one client
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*/
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struct echo_state {
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struct tevent_context *ev;
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int fd;
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uint8_t *buf;
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};
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static int echo_state_destructor(struct echo_state *s);
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static void echo_read_done(struct tevent_req *subreq);
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static void echo_writeall_done(struct tevent_req *subreq);
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static struct tevent_req *echo_send(TALLOC_CTX *mem_ctx,
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struct tevent_context *ev,
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int fd, size_t bufsize)
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{
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struct tevent_req *req, *subreq;
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struct echo_state *state;
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req = tevent_req_create(mem_ctx, &state, struct echo_state);
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if (req == NULL) {
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return NULL;
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}
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state->ev = ev;
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state->fd = fd;
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talloc_set_destructor(state, echo_state_destructor);
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state->buf = talloc_array(state, uint8_t, bufsize);
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if (tevent_req_nomem(state->buf, req)) {
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return tevent_req_post(req, ev);
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}
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subreq = read_send(state, state->ev, state->fd,
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state->buf, talloc_get_size(state->buf));
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if (tevent_req_nomem(subreq, req)) {
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return tevent_req_post(req, ev);
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}
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tevent_req_set_callback(subreq, echo_read_done, req);
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return req;
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}
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static int echo_state_destructor(struct echo_state *s)
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{
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if (s->fd != -1) {
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printf("Closing client fd %d\n", s->fd);
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close(s->fd);
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s->fd = -1;
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}
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return 0;
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}
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static void echo_read_done(struct tevent_req *subreq)
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{
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struct tevent_req *req = tevent_req_callback_data(
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subreq, struct tevent_req);
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struct echo_state *state = tevent_req_data(
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req, struct echo_state);
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ssize_t nread;
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int err;
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nread = read_recv(subreq, &err);
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TALLOC_FREE(subreq);
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if (nread == -1) {
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tevent_req_error(req, err);
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return;
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}
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if (nread == 0) {
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tevent_req_done(req);
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return;
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}
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subreq = writeall_send(state, state->ev, state->fd, state->buf, nread);
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if (tevent_req_nomem(subreq, req)) {
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return;
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}
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tevent_req_set_callback(subreq, echo_writeall_done, req);
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}
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static void echo_writeall_done(struct tevent_req *subreq)
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{
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struct tevent_req *req = tevent_req_callback_data(
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subreq, struct tevent_req);
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struct echo_state *state = tevent_req_data(
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req, struct echo_state);
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ssize_t nwritten;
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int err;
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nwritten = writeall_recv(subreq, &err);
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TALLOC_FREE(subreq);
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if (nwritten == -1) {
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if (err == EPIPE) {
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tevent_req_done(req);
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return;
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}
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tevent_req_error(req, err);
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return;
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}
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subreq = read_send(state, state->ev, state->fd,
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state->buf, talloc_get_size(state->buf));
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if (tevent_req_nomem(subreq, req)) {
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return;
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}
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tevent_req_set_callback(subreq, echo_read_done, req);
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}
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static bool echo_recv(struct tevent_req *req, int *perr)
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{
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int err;
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if (tevent_req_is_unix_error(req, &err)) {
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*perr = err;
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return false;
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}
|
||||
return true;
|
||||
}
|
||||
|
||||
/**
|
||||
* @brief Full echo handler code accepting and handling clients
|
||||
*/
|
||||
|
||||
struct echo_server_state {
|
||||
struct tevent_context *ev;
|
||||
int listen_sock;
|
||||
};
|
||||
|
||||
static void echo_server_accepted(struct tevent_req *subreq);
|
||||
static void echo_server_client_done(struct tevent_req *subreq);
|
||||
|
||||
static struct tevent_req *echo_server_send(TALLOC_CTX *mem_ctx,
|
||||
struct tevent_context *ev,
|
||||
int listen_sock)
|
||||
{
|
||||
struct tevent_req *req, *subreq;
|
||||
struct echo_server_state *state;
|
||||
|
||||
req = tevent_req_create(mem_ctx, &state,
|
||||
struct echo_server_state);
|
||||
if (req == NULL) {
|
||||
return NULL;
|
||||
}
|
||||
state->ev = ev;
|
||||
state->listen_sock = listen_sock;
|
||||
|
||||
subreq = accept_send(state, state->ev, state->listen_sock);
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return tevent_req_post(req, ev);
|
||||
}
|
||||
tevent_req_set_callback(subreq, echo_server_accepted, req);
|
||||
return req;
|
||||
}
|
||||
|
||||
static void echo_server_accepted(struct tevent_req *subreq)
|
||||
{
|
||||
struct tevent_req *req = tevent_req_callback_data(
|
||||
subreq, struct tevent_req);
|
||||
struct echo_server_state *state = tevent_req_data(
|
||||
req, struct echo_server_state);
|
||||
int sock, err;
|
||||
|
||||
sock = accept_recv(subreq, NULL, NULL, &err);
|
||||
TALLOC_FREE(subreq);
|
||||
if (sock == -1) {
|
||||
tevent_req_error(req, err);
|
||||
return;
|
||||
}
|
||||
|
||||
printf("new client fd %d\n", sock);
|
||||
|
||||
subreq = echo_send(state, state->ev, sock, 100);
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return;
|
||||
}
|
||||
tevent_req_set_callback(subreq, echo_server_client_done, req);
|
||||
|
||||
subreq = accept_send(state, state->ev, state->listen_sock);
|
||||
if (tevent_req_nomem(subreq, req)) {
|
||||
return;
|
||||
}
|
||||
tevent_req_set_callback(subreq, echo_server_accepted, req);
|
||||
}
|
||||
|
||||
static void echo_server_client_done(struct tevent_req *subreq)
|
||||
{
|
||||
bool ret;
|
||||
int err;
|
||||
|
||||
ret = echo_recv(subreq, &err);
|
||||
TALLOC_FREE(subreq);
|
||||
|
||||
if (ret) {
|
||||
printf("Client done\n");
|
||||
} else {
|
||||
printf("Client failed: %s\n", strerror(err));
|
||||
}
|
||||
}
|
||||
|
||||
static bool echo_server_recv(struct tevent_req *req, int *perr)
|
||||
{
|
||||
int err;
|
||||
|
||||
if (tevent_req_is_unix_error(req, &err)) {
|
||||
*perr = err;
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
int main(int argc, const char **argv)
|
||||
{
|
||||
int ret, port, listen_sock, err;
|
||||
struct tevent_context *ev;
|
||||
struct sockaddr_in addr;
|
||||
struct tevent_req *req;
|
||||
bool result;
|
||||
|
||||
if (argc != 2) {
|
||||
fprintf(stderr, "Usage: %s <port>\n", argv[0]);
|
||||
exit(1);
|
||||
}
|
||||
|
||||
port = atoi(argv[1]);
|
||||
|
||||
printf("listening on port %d\n", port);
|
||||
|
||||
listen_sock = socket(AF_INET, SOCK_STREAM, 0);
|
||||
|
||||
if (listen_sock == -1) {
|
||||
perror("socket() failed");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
memset(&addr, 0, sizeof(addr));
|
||||
|
||||
addr.sin_family = AF_INET;
|
||||
addr.sin_port = htons(port);
|
||||
|
||||
ret = bind(listen_sock, (struct sockaddr *)&addr, sizeof(addr));
|
||||
if (ret == -1) {
|
||||
perror("bind() failed");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
ret = listen(listen_sock, 5);
|
||||
if (ret == -1) {
|
||||
perror("listen() failed");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
ev = tevent_context_init(NULL);
|
||||
if (ev == NULL) {
|
||||
fprintf(stderr, "tevent_context_init failed\n");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
req = echo_server_send(ev, ev, listen_sock);
|
||||
if (req == NULL) {
|
||||
fprintf(stderr, "echo_server_send failed\n");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
if (!tevent_req_poll(req, ev)) {
|
||||
perror("tevent_req_poll() failed");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
result = echo_server_recv(req, &err);
|
||||
TALLOC_FREE(req);
|
||||
if (!result) {
|
||||
fprintf(stderr, "echo_server failed: %s\n", strerror(err));
|
||||
exit(1);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
Loading…
Reference in New Issue
Block a user