libevent-filter-issue-616.c

#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/event.h>

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

struct ctx
{
};

static enum bufferevent_filter_result
proxy_in(struct evbuffer *src, struct evbuffer* dst, ev_ssize_t lim,
	enum bufferevent_flush_mode state, void *_ctx)
{
	struct ctx *ctx = _ctx;
	size_t slen = evbuffer_get_length(src);
	size_t dlen = evbuffer_get_length(dst);
	fprintf(stderr, "%10s: src=%p/%zu->dst=%p/%zu\n", __func__, src, slen, dst, dlen);
	evbuffer_remove_buffer(src, dst, lim);
	return BEV_OK;
}
static enum bufferevent_filter_result
proxy_out(struct evbuffer *src, struct evbuffer* dst, ev_ssize_t lim,
	enum bufferevent_flush_mode state, void *_ctx)
{
	struct ctx *ctx = _ctx;
	size_t slen = evbuffer_get_length(src);
	size_t dlen = evbuffer_get_length(dst);
	fprintf(stderr, "%10s: src=%p/%zu->dst=%p/%zu\n", __func__, src, slen, dst, dlen);
	evbuffer_remove_buffer(src, dst, lim);
	return BEV_OK;
}

static void readcb(struct bufferevent *bev, void *_ctx)
{
	struct ctx *ctx = _ctx;
	struct evbuffer *in  = bufferevent_get_input(bev);
	struct evbuffer *out = bufferevent_get_output(bev);
	size_t ilen = evbuffer_get_length(in);
	size_t olen = evbuffer_get_length(out);
	fprintf(stderr, "%10s: in=%p/%zu, out=%p/%zu\n", __func__, in, ilen, out, olen);

	const char *data = evbuffer_pullup(in, ilen);
	fprintf(stdout, "readcb: {'%.*s'}\n", (int)ilen, data);
}
static void writecb(struct bufferevent *bev, void *_ctx)
{
	struct ctx *ctx = _ctx;
	struct evbuffer *in  = bufferevent_get_input(bev);
	struct evbuffer *out = bufferevent_get_output(bev);
	size_t ilen = evbuffer_get_length(in);
	size_t olen = evbuffer_get_length(out);
	fprintf(stderr, "%10s: in=%p/%zu, out=%p/%zu\n", __func__, in, ilen, out, olen);
}
static void errorcb(struct bufferevent *bev, short what, void *_ctx)
{
	struct ctx *ctx = _ctx;
	struct evbuffer *in  = bufferevent_get_input(bev);
	struct evbuffer *out = bufferevent_get_output(bev);
	size_t ilen = evbuffer_get_length(in);
	size_t olen = evbuffer_get_length(out);
	fprintf(stderr, "%10s: in=%p/%zu, out=%p/%zu, what=%hx\n", __func__, in, ilen, out, olen, what);
}


int main(int argc, const char **argv)
{
	(void)argc;
	(void)argv;

	struct event_base *base;
	struct bufferevent *bev[2];
	int pair[2];
	int err;
	int be_flags;
	struct ctx ctx_in, ctx_out;

	be_flags |= BEV_OPT_CLOSE_ON_FREE;

	setbuf(stdout, NULL);
	setbuf(stderr, NULL);

	err = evutil_socketpair(AF_UNIX, SOCK_STREAM, 0, pair);
	assert(!err && "socketpair");
	err = evutil_make_socket_nonblocking(pair[0]);
	assert(!err && "nonblocking[0]");
	err = evutil_make_socket_nonblocking(pair[1]);
	assert(!err && "nonblocking[1]");

	base = event_base_new();
	assert(base && "event_base_new");

	bev[0] = bufferevent_socket_new(base, pair[0], 0);
	assert(bev[0] && "be_sock[0]");
	bev[1] = bufferevent_socket_new(base, pair[1], 0);
	assert(bev[1] && "be_sock[1]");

	bev[0] = bufferevent_filter_new(bev[0], NULL, proxy_out, be_flags, NULL, &ctx_in);
	assert(bev[0] && "be_filter[out/0]");
	bev[1] = bufferevent_filter_new(bev[1], proxy_in, NULL,  be_flags, NULL, &ctx_out);
	assert(bev[1] && "be_filter[in/1]");

	bufferevent_setcb(bev[0], readcb, writecb, errorcb, NULL);
	bufferevent_setcb(bev[1], readcb, writecb, errorcb, NULL);

	bufferevent_enable(bev[1], EV_READ);
	bufferevent_write(bev[0], "foobar", 6);

	err = event_base_loop(base, 0);
	assert(!err && "loop");

	bufferevent_free(bev[0]);
	bufferevent_free(bev[1]);
	event_base_free(base);

	return EXIT_SUCCESS;
}