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Add sabridge for socket activation of traditional daemons

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This commit is contained in:
David Strauss 2013-10-14 16:41:47 -07:00
parent d7d1c8f983
commit 912b54ad47
6 changed files with 878 additions and 1 deletions
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1
.gitignore vendored
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@ -71,6 +71,7 @@
/systemd-reply-password
/systemd-rfkill
/systemd-run
/systemd-sabridge
/systemd-shutdown
/systemd-shutdownd
/systemd-sleep

1
Makefile-man.am
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@ -66,6 +66,7 @@ MANPAGES += \
man/systemd-nspawn.1 \
man/systemd-remount-fs.service.8 \
man/systemd-run.1 \
man/systemd-sabridge.1 \
man/systemd-shutdownd.service.8 \
man/systemd-sleep.conf.5 \
man/systemd-suspend.service.8 \

20
Makefile.am
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@ -5,6 +5,7 @@
# Copyright 2010-2012 Lennart Poettering
# Copyright 2010-2012 Kay Sievers
# Copyright 2013 Zbigniew Jędrzejewski-Szmek
# Copyright 2013 David Strauss
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
@ -298,7 +299,8 @@ bin_PROGRAMS = \
systemd-detect-virt \
systemd-delta \
systemd-analyze \
systemd-run
systemd-run \
systemd-sabridge
dist_bin_SCRIPTS = \
src/kernel-install/kernel-install
@ -3206,6 +3208,22 @@ endif
EXTRA_DIST += \
units/systemd-journal-gatewayd.service.in
# ------------------------------------------------------------------------------
systemd_sabridge_SOURCES = \
src/sabridge/sabridge.c
systemd_sabridge_LDADD = \
libsystemd-shared.la \
libsystemd-logs.la \
libsystemd-journal-internal.la \
libsystemd-id128-internal.la \
libsystemd-daemon.la \
libsystemd-bus.la
systemd_sabridge_CFLAGS = \
$(AM_CFLAGS)
# ------------------------------------------------------------------------------
if ENABLE_COREDUMP
systemd_coredump_SOURCES = \

254
man/systemd-sabridge.xml Normal file
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@ -0,0 +1,254 @@
<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2013 David Strauss
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="systemd-sabridge">
<refentryinfo>
<title>systemd-sabridge</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>David</firstname>
<surname>Strauss</surname>
<email>david@davidstrauss.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-sabridge</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-sabridge</refname>
<refpurpose>Inherit a socket. Bidirectionally
proxy.</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-sabridge</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain"><replaceable>HOSTNAME-OR-IP</replaceable></arg>
<arg choice="plain"><replaceable>PORT-OR-SERVICE</replaceable></arg>
</cmdsynopsis>
<cmdsynopsis>
<command>systemd-sabridge</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="plain"><replaceable>UNIX-DOMAIN-SOCKET-PATH</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>systemd-sabridge</command>provides a proxy
to socket-activate services that do not yet support
native socket activation. On behalf of the daemon,
the proxy inherits the socket from systemd, accepts
each client connection, opens a connection to the server
for each client, and then bidirectionally forwards
data between the two.</para>
<para>This utility's behavior is similar to
<citerefentry><refentrytitle>socat</refentrytitle><manvolnum>1</manvolnum> </citerefentry>.
The main differences for <command>systemd-sabridge</command>
are support for socket activation with
<literal>Accept=false</literal> and an event-driven
design that scales better with the number of
connections.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>-h</option></term>
<term><option>--help</option></term>
<listitem>
<para>Prints a short help
text and exits.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<listitem>
<para>Prints a version
string and exits.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--ignore-env</option></term>
<listitem>
<para>Skips verification of
the expected PID and file
descriptor numbers. Use if
invoked indirectly, for
example with a shell script
rather than with
<option>ExecStart=/usr/bin/systemd-sabridge</option>
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success 0 is returned, a non-zero failure
code otherwise.</para>
</refsect1>
<refsect1>
<title>Examples</title>
<refsect2>
<title>Direct-Use Example</title>
<para>Use two services with a dependency
and no namespace isolation.</para>
<example label="bridge socket unit">
<title>/etc/systemd/system/bridge-to-nginx.socket</title>
<programlisting>
<![CDATA[[Socket]
ListenStream=80
[Install]
WantedBy=socket.target]]>
</programlisting>
</example>
<example label="bridge service unit">
<title>/etc/systemd/system/bridge-to-nginx.service</title>
<programlisting>
<![CDATA[[Unit]
After=nginx.service
Requires=nginx.service
[Service]
ExecStart=/usr/bin/systemd-sabridge /tmp/nginx.sock
PrivateTmp=true
PrivateNetwork=true]]>
</programlisting>
</example>
<example label="nginx configuration">
<title>/etc/nginx/nginx.conf</title>
<programlisting>
<![CDATA[[...]
server {
listen unix:/tmp/nginx.sock;
[...]]]>
</programlisting>
</example>
<example label="commands">
<programlisting>
<![CDATA[$ sudo systemctl --system daemon-reload
$ sudo systemctl start bridge-to-nginx.socket
$ sudo systemctl enable bridge-to-nginx.socket
$ curl http://localhost:80/]]>
</programlisting>
</example>
</refsect2>
<refsect2>
<title>Indirect-Use Example</title>
<para>Use a shell script to isolate the
service and bridge into the same namespace.
This is particularly useful for running
TCP-only daemons without the daemon
affecting ports on regular
interfaces.</para>
<example label="combined bridge and nginx socket unit">
<title>
/etc/systemd/system/bridge-with-nginx.socket</title>
<programlisting>
<![CDATA[[Socket]
ListenStream=80
[Install]
WantedBy=socket.target]]>
</programlisting>
</example>
<example label="combined bridge and nginx service unit">
<title>
/etc/systemd/system/bridge-with-nginx.service</title>
<programlisting>
<![CDATA[[Unit]
After=syslog.target remote-fs.target nss-lookup.target
[Service]
ExecStartPre=/usr/sbin/nginx -t
ExecStart=/usr/bin/sabridge-nginx.sh
PrivateTmp=true
PrivateNetwork=true]]>
</programlisting>
</example>
<example label="shell script">
<title>
/usr/bin/sabridge-nginx.sh</title>
<programlisting>
<![CDATA[#!/bin/sh
/usr/sbin/nginx
while [ ! -f /tmp/nginx.pid ]
do
/usr/bin/inotifywait /tmp/nginx.pid
done
/usr/bin/systemd-sabridge --ignore-env localhost 8080]]>
</programlisting>
</example>
<example label="nginx configuration">
<title>
/etc/nginx/nginx.conf</title>
<programlisting>
<![CDATA[[...]
server {
listen 8080;
listen unix:/tmp/nginx.sock;
[...]]]>
</programlisting>
</example>
<example label="commands">
<programlisting>
<![CDATA[$ sudo systemctl --system daemon-reload
$ sudo systemctl start bridge-with-nginx.socket
$ sudo systemctl enable bridge-with-nginx.socket
$ curl http://localhost:80/]]>
</programlisting>
</example>
</refsect2>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry>
<refentrytitle>
systemd.service</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>
systemd.socket</refentrytitle>
<manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>systemctl</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>socat</refentrytitle>
<manvolnum>1</manvolnum>
</citerefentry></para>
</refsect1>
</refentry>

28
src/sabridge/Makefile Normal file
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@ -0,0 +1,28 @@
# This file is part of systemd.
#
# Copyright 2010 Lennart Poettering
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# systemd is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with systemd; If not, see <http://www.gnu.org/licenses/>.
# This file is a dirty trick to simplify compilation from within
# emacs. This file is not intended to be distributed. So, don't touch
# it, even better ignore it!
all:
$(MAKE) -C ..
clean:
$(MAKE) -C .. clean
.PHONY: all clean

575
src/sabridge/sabridge.c Normal file
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@ -0,0 +1,575 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 David Strauss
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <arpa/inet.h>
#include <errno.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <sys/fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include "log.h"
#include "sd-daemon.h"
#include "sd-event.h"
#include "socket-util.h"
#include "util.h"
#define BUFFER_SIZE 4096
#define _cleanup_freeaddrinfo_ _cleanup_(freeaddrinfop)
unsigned int total_clients = 0;
DEFINE_TRIVIAL_CLEANUP_FUNC(struct addrinfo *, freeaddrinfo);
struct proxy {
int listen_fd;
bool ignore_env;
bool remote_is_inet;
const char *remote_host;
const char *remote_service;
};
struct connection {
int fd;
sd_event_source *w_recv;
sd_event_source *w_send;
struct connection *c_destination;
size_t buffer_filled_len;
size_t buffer_sent_len;
char buffer[BUFFER_SIZE];
};
static void free_connection(struct connection *c) {
log_debug("Freeing fd=%d (conn %p).", c->fd, c);
sd_event_source_unref(c->w_recv);
sd_event_source_unref(c->w_send);
close(c->fd);
free(c);
}
static int send_buffer(struct connection *sender) {
struct connection *receiver = sender->c_destination;
ssize_t len;
int r = 0;
/* We cannot assume that even a partial send() indicates that
* the next send() will block. Loop until it does. */
while (sender->buffer_filled_len > sender->buffer_sent_len) {
len = send(receiver->fd, sender->buffer + sender->buffer_sent_len, sender->buffer_filled_len - sender->buffer_sent_len, 0);
log_debug("send(%d, ...)=%ld", receiver->fd, len);
if (len < 0) {
if (errno != EWOULDBLOCK && errno != EAGAIN) {
log_error("Error %d in send to fd=%d: %m", errno, receiver->fd);
return -errno;
}
else {
/* send() is in a blocking state. */
break;
}
}
/* len < 0 can't occur here. len == 0 is possible but
* undefined behavior for nonblocking send(). */
assert(len > 0);
sender->buffer_sent_len += len;
}
log_debug("send(%d, ...) completed with %lu bytes still buffered.", receiver->fd, sender->buffer_filled_len - sender->buffer_sent_len);
/* Detect a would-block state or partial send. */
if (sender->buffer_filled_len > sender->buffer_sent_len) {
/* If the buffer is full, disable events coming for recv. */
if (sender->buffer_filled_len == BUFFER_SIZE) {
r = sd_event_source_set_enabled(sender->w_recv, SD_EVENT_OFF);
if (r < 0) {
log_error("Error %d disabling recv for fd=%d: %s", r, sender->fd, strerror(-r));
return r;
}
}
/* Watch for when the recipient can be sent data again. */
r = sd_event_source_set_enabled(receiver->w_send, SD_EVENT_ON);
if (r < 0) {
log_error("Error %d enabling send for fd=%d: %s", r, receiver->fd, strerror(-r));
return r;
}
log_debug("Done with recv for fd=%d. Waiting on send for fd=%d.", sender->fd, receiver->fd);
return r;
}
/* If we sent everything without blocking, the buffer is now empty. */
sender->buffer_filled_len = 0;
sender->buffer_sent_len = 0;
/* Unmute the sender, in case the buffer was full. */
r = sd_event_source_set_enabled(sender->w_recv, SD_EVENT_ON);
if (r < 0) {
log_error("Error %d enabling recv for fd=%d: %s", r, sender->fd, strerror(-r));
return r;
}
/* Mute the recipient, as we have no data to send now. */
r = sd_event_source_set_enabled(receiver->w_send, SD_EVENT_OFF);
if (r < 0) {
log_error("Error %d disabling send for fd=%d: %s", r, receiver->fd, strerror(-r));
return r;
}
return 0;
}
static int transfer_data_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
struct connection *c = (struct connection *) userdata;
int r = 0;
ssize_t len;
assert(revents & (EPOLLIN | EPOLLOUT));
assert(fd == c->fd);
log_debug("Got event revents=%d from fd=%d (conn %p).", revents, fd, c);
if (revents & EPOLLIN) {
log_debug("About to recv up to %lu bytes from fd=%d (%lu/BUFFER_SIZE).", BUFFER_SIZE - c->buffer_filled_len, fd, c->buffer_filled_len);
assert(s == c->w_recv);
/* Receive until the buffer's full, there's no more data,
* or the client/server disconnects. */
while (c->buffer_filled_len < BUFFER_SIZE) {
len = recv(fd, c->buffer + c->buffer_filled_len, BUFFER_SIZE - c->buffer_filled_len, 0);
log_debug("recv(%d, ...)=%ld", fd, len);
if (len < 0) {
if (errno != EWOULDBLOCK && errno != EAGAIN) {
log_error("Error %d in recv from fd=%d: %m", errno, fd);
return -errno;
}
else {
/* recv() is in a blocking state. */
break;
}
}
else if (len == 0) {
log_debug("Clean disconnection from fd=%d", fd);
total_clients--;
free_connection(c->c_destination);
free_connection(c);
return 0;
}
assert(len > 0);
log_debug("Recording that the buffer got %ld more bytes full.", len);
c->buffer_filled_len += len;
log_debug("Buffer now has %ld bytes full.", c->buffer_filled_len);
}
/* Try sending the data immediately. */
return send_buffer(c);
}
else {
assert(s == c->w_send);
return send_buffer(c->c_destination);
}
return r;
}
/* Once sending to the server is unblocked, set up the real watchers. */
static int connected_to_server_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
struct sd_event *e = NULL;
struct connection *c_server_to_client = (struct connection *) userdata;
struct connection *c_client_to_server = c_server_to_client->c_destination;
int r;
assert(revents & EPOLLOUT);
e = sd_event_get(s);
/* Cancel the initial write watcher for the server. */
sd_event_source_unref(s);
log_debug("Connected to server. Initializing watchers for receiving data.");
/* A disabled send watcher for the server. */
r = sd_event_add_io(e, c_server_to_client->fd, EPOLLOUT, transfer_data_cb, c_server_to_client, &c_server_to_client->w_send);
if (r < 0) {
log_error("Error %d creating send watcher for fd=%d: %s", r, c_server_to_client->fd, strerror(-r));
goto fail;
}
r = sd_event_source_set_enabled(c_server_to_client->w_send, SD_EVENT_OFF);
if (r < 0) {
log_error("Error %d muting send for fd=%d: %s", r, c_server_to_client->fd, strerror(-r));
goto finish;
}
/* A recv watcher for the server. */
r = sd_event_add_io(e, c_server_to_client->fd, EPOLLIN, transfer_data_cb, c_server_to_client, &c_server_to_client->w_recv);
if (r < 0) {
log_error("Error %d creating recv watcher for fd=%d: %s", r, c_server_to_client->fd, strerror(-r));
goto fail;
}
/* A disabled send watcher for the client. */
r = sd_event_add_io(e, c_client_to_server->fd, EPOLLOUT, transfer_data_cb, c_client_to_server, &c_client_to_server->w_send);
if (r < 0) {
log_error("Error %d creating send watcher for fd=%d: %s", r, c_client_to_server->fd, strerror(-r));
goto fail;
}
r = sd_event_source_set_enabled(c_client_to_server->w_send, SD_EVENT_OFF);
if (r < 0) {
log_error("Error %d muting send for fd=%d: %s", r, c_client_to_server->fd, strerror(-r));
goto finish;
}
/* A recv watcher for the client. */
r = sd_event_add_io(e, c_client_to_server->fd, EPOLLIN, transfer_data_cb, c_client_to_server, &c_client_to_server->w_recv);
if (r < 0) {
log_error("Error %d creating recv watcher for fd=%d: %s", r, c_client_to_server->fd, strerror(-r));
goto fail;
}
goto finish;
fail:
free_connection(c_client_to_server);
free_connection(c_server_to_client);
finish:
return r;
}
static int get_server_connection_fd(const struct proxy *proxy) {
int server_fd;
int r = -EBADF;
int len;
if (proxy->remote_is_inet) {
int s;
_cleanup_freeaddrinfo_ struct addrinfo *result = NULL;
struct addrinfo hints = {.ai_family = AF_UNSPEC,
.ai_socktype = SOCK_STREAM,
.ai_flags = AI_PASSIVE};
log_debug("Looking up address info for %s:%s", proxy->remote_host, proxy->remote_service);
s = getaddrinfo(proxy->remote_host, proxy->remote_service, &hints, &result);
if (s != 0) {
log_error("getaddrinfo error (%d): %s", s, gai_strerror(s));
return r;
}
if (result == NULL) {
log_error("getaddrinfo: no result");
return r;
}
/* @TODO: Try connecting to all results instead of just the first. */
server_fd = socket(result->ai_family, result->ai_socktype | SOCK_NONBLOCK, result->ai_protocol);
if (server_fd < 0) {
log_error("Error %d creating socket: %m", errno);
return r;
}
r = connect(server_fd, result->ai_addr, result->ai_addrlen);
/* Ignore EINPROGRESS errors because they're expected for a nonblocking socket. */
if (r < 0 && errno != EINPROGRESS) {
log_error("Error %d while connecting to socket %s:%s: %m", errno, proxy->remote_host, proxy->remote_service);
return r;
}
}
else {
struct sockaddr_un remote;
server_fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0);
if (server_fd < 0) {
log_error("Error %d creating socket: %m", errno);
return -EBADFD;
}
remote.sun_family = AF_UNIX;
strncpy(remote.sun_path, proxy->remote_host, sizeof(remote.sun_path));
len = strlen(remote.sun_path) + sizeof(remote.sun_family);
r = connect(server_fd, (struct sockaddr *) &remote, len);
if (r < 0 && errno != EINPROGRESS) {
log_error("Error %d while connecting to Unix domain socket %s: %m", errno, proxy->remote_host);
return -EBADFD;
}
}
log_debug("Server connection is fd=%d", server_fd);
return server_fd;
}
static int accept_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
struct proxy *proxy = (struct proxy *) userdata;
struct connection *c_server_to_client;
struct connection *c_client_to_server;
int r = 0;
union sockaddr_union sa;
socklen_t salen = sizeof(sa);
assert(revents & EPOLLIN);
c_server_to_client = malloc0(sizeof(struct connection));
if (c_server_to_client == NULL) {
log_oom();
goto fail;
}
c_client_to_server = malloc0(sizeof(struct connection));
if (c_client_to_server == NULL) {
log_oom();
goto fail;
}
c_server_to_client->fd = get_server_connection_fd(proxy);
if (c_server_to_client->fd < 0) {
log_error("Error initiating server connection.");
goto fail;
}
c_client_to_server->fd = accept(fd, (struct sockaddr *) &sa, &salen);
if (c_client_to_server->fd < 0) {
log_error("Error accepting client connection.");
goto fail;
}
/* Unlike on BSD, client sockets do not inherit nonblocking status
* from the listening socket. */
r = fd_nonblock(c_client_to_server->fd, true);
if (r < 0) {
log_error("Error %d marking client connection as nonblocking: %s", r, strerror(-r));
goto fail;
}
if (sa.sa.sa_family == AF_INET || sa.sa.sa_family == AF_INET6) {
char sa_str[INET6_ADDRSTRLEN];
const char *success;
success = inet_ntop(sa.sa.sa_family, &sa.in6.sin6_addr, sa_str, INET6_ADDRSTRLEN);
if (success == NULL)
log_warning("Error %d calling inet_ntop: %m", errno);
else
log_debug("Accepted client connection from %s as fd=%d", sa_str, c_client_to_server->fd);
}
else {
log_debug("Accepted client connection (non-IP) as fd=%d", c_client_to_server->fd);
}
total_clients++;
log_debug("Client fd=%d (conn %p) successfully connected. Total clients: %u", c_client_to_server->fd, c_client_to_server, total_clients);
log_debug("Server fd=%d (conn %p) successfully initialized.", c_server_to_client->fd, c_server_to_client);
/* Initialize watcher for send to server; this shows connectivity. */
r = sd_event_add_io(sd_event_get(s), c_server_to_client->fd, EPOLLOUT, connected_to_server_cb, c_server_to_client, &c_server_to_client->w_send);
if (r < 0) {
log_error("Error %d creating connectivity watcher for fd=%d: %s", r, c_server_to_client->fd, strerror(-r));
goto fail;
}
/* Allow lookups of the opposite connection. */
c_server_to_client->c_destination = c_client_to_server;
c_client_to_server->c_destination = c_server_to_client;
goto finish;
fail:
log_warning("Accepting a client connection or connecting to the server failed.");
free_connection(c_client_to_server);
free_connection(c_server_to_client);
finish:
/* Preserve the main loop even if a single proxy setup fails. */
return 0;
}
static int run_main_loop(struct proxy *proxy) {
int r = EXIT_SUCCESS;
struct sd_event *e = NULL;
sd_event_source *w_accept = NULL;
r = sd_event_new(&e);
if (r < 0)
goto finish;
r = fd_nonblock(proxy->listen_fd, true);
if (r < 0)
goto finish;
log_debug("Initializing main listener fd=%d", proxy->listen_fd);
sd_event_add_io(e, proxy->listen_fd, EPOLLIN, accept_cb, proxy, &w_accept);
log_debug("Initialized main listener. Entering loop.");
sd_event_loop(e);
finish:
sd_event_source_unref(w_accept);
sd_event_unref(e);
return r;
}
static int help(void) {
printf("%s hostname-or-ip port-or-service\n"
"%s unix-domain-socket-path\n\n"
"Inherit a socket. Bidirectionally proxy.\n\n"
" -h --help Show this help\n"
" --version Print version and exit\n"
" --ignore-env Ignore expected systemd environment\n",
program_invocation_short_name,
program_invocation_short_name);
return 0;
}
static void version(void) {
puts(PACKAGE_STRING " sabridge");
}
static int parse_argv(int argc, char *argv[], struct proxy *p) {
enum {
ARG_VERSION = 0x100,
ARG_IGNORE_ENV
};
static const struct option options[] = {
{ "help", no_argument, NULL, 'h' },
{ "version", no_argument, NULL, ARG_VERSION },
{ "ignore-env", no_argument, NULL, ARG_IGNORE_ENV},
{ NULL, 0, NULL, 0 }
};
int c;
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {
switch (c) {
case 'h':
help();
return 0;
case '?':
return -EINVAL;
case ARG_VERSION:
version();
return 0;
case ARG_IGNORE_ENV:
p->ignore_env = true;
continue;
default:
log_error("Unknown option code %c", c);
return -EINVAL;
}
}
if (optind + 1 != argc && optind + 2 != argc) {
log_error("Incorrect number of positional arguments.");
help();
return -EINVAL;
}
p->remote_host = argv[optind];
assert(p->remote_host);
p->remote_is_inet = p->remote_host[0] != '/';
if (optind == argc - 2) {
if (!p->remote_is_inet) {
log_error("A port or service is not allowed for Unix socket destinations.");
help();
return -EINVAL;
}
p->remote_service = argv[optind + 1];
assert(p->remote_service);
} else if (p->remote_is_inet) {
log_error("A port or service is required for IP destinations.");
help();
return -EINVAL;
}
return 1;
}
int main(int argc, char *argv[]) {
struct proxy p = {};
int r;
log_parse_environment();
log_open();
r = parse_argv(argc, argv, &p);
if (r <= 0)
goto finish;
p.listen_fd = SD_LISTEN_FDS_START;
if (!p.ignore_env) {
int n;
n = sd_listen_fds(1);
if (n == 0) {
log_error("Found zero inheritable sockets. Are you sure this is running as a socket-activated service?");
r = EXIT_FAILURE;
goto finish;
} else if (n < 0) {
log_error("Error %d while finding inheritable sockets: %s", n, strerror(-n));
r = EXIT_FAILURE;
goto finish;
} else if (n > 1) {
log_error("Can't listen on more than one socket.");
r = EXIT_FAILURE;
goto finish;
}
}
/* @TODO: Check if this proxy can work with datagram sockets. */
r = sd_is_socket(p.listen_fd, 0, SOCK_STREAM, 1);
if (r < 0) {
log_error("Error %d while checking inherited socket: %s", r, strerror(-r));
goto finish;
}
log_info("Starting the socket activation bridge with listener fd=%d.", p.listen_fd);
r = run_main_loop(&p);
if (r < 0) {
log_error("Error %d from main loop.", r);
goto finish;
}
finish:
log_close();
return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}