Adding upstream version 1.9.13p3.upstream/1.9.13p3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2012 insertions, 0 deletions

diff --git a/logsrvd/logsrvd.c b/logsrvd/logsrvd.c
new file mode 100644
index 0000000..17edb84
--- /dev/null
+++ b/logsrvd/logsrvd.c
@@ -0,0 +1,2012 @@
+/*
+ * SPDX-License-Identifier: ISC
+ *
+ * Copyright (c) 2019-2022 Todd C. Miller <Todd.Miller@sudo.ws>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/*
+ * This is an open source non-commercial project. Dear PVS-Studio, please check it.
+ * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+ */
+
+#include <config.h>
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <netinet/tcp.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include "compat/stdbool.h"
+#endif /* HAVE_STDBOOL_H */
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+#ifdef HAVE_GETOPT_LONG
+# include <getopt.h>
+# else
+# include "compat/getopt.h"
+#endif /* HAVE_GETOPT_LONG */
+
+#define NEED_INET_NTOP		/* to expose sudo_inet_ntop in sudo_compat.h */
+
+#include "pathnames.h"
+#include "sudo_compat.h"
+#include "sudo_conf.h"
+#include "sudo_debug.h"
+#include "sudo_event.h"
+#include "sudo_eventlog.h"
+#include "sudo_fatal.h"
+#include "sudo_gettext.h"
+#include "sudo_json.h"
+#include "sudo_iolog.h"
+#include "sudo_queue.h"
+#include "sudo_rand.h"
+#include "sudo_util.h"
+
+#include "logsrvd.h"
+#include "hostcheck.h"
+
+#ifndef O_NOFOLLOW
+# define O_NOFOLLOW 0
+#endif
+
+/*
+ * Sudo I/O audit server.
+ */
+static int logsrvd_debug_instance = SUDO_DEBUG_INSTANCE_INITIALIZER;
+TAILQ_HEAD(connection_list, connection_closure);
+static struct connection_list connections = TAILQ_HEAD_INITIALIZER(connections);
+static struct listener_list listeners = TAILQ_HEAD_INITIALIZER(listeners);
+static const char server_id[] = "Sudo Audit Server " PACKAGE_VERSION;
+static const char *conf_file = _PATH_SUDO_LOGSRVD_CONF;
+
+/* Event loop callbacks. */
+static void client_msg_cb(int fd, int what, void *v);
+static void server_msg_cb(int fd, int what, void *v);
+static void server_commit_cb(int fd, int what, void *v);
+#if defined(HAVE_OPENSSL)
+static void tls_handshake_cb(int fd, int what, void *v);
+#endif
+
+/*
+ * Free a struct connection_closure container and its contents.
+ */
+static void
+connection_closure_free(struct connection_closure *closure)
+{
+    debug_decl(connection_closure_free, SUDO_DEBUG_UTIL);
+
+    if (closure != NULL) {
+	bool shutting_down = closure->state == SHUTDOWN;
+	struct sudo_event_base *evbase = closure->evbase;
+	struct connection_buffer *buf;
+
+	TAILQ_REMOVE(&connections, closure, entries);
+
+	if (closure->state == CONNECTING && closure->journal != NULL) {
+	    /* Failed to relay journal file, retry later. */
+	    logsrvd_queue_insert(closure);
+	}
+	if (closure->relay_closure != NULL)
+	    relay_closure_free(closure->relay_closure);
+#if defined(HAVE_OPENSSL)
+	if (closure->ssl != NULL) {
+	    /* Must call SSL_shutdown() before closing closure->sock. */
+	    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+		"closing down TLS connection from %s", closure->ipaddr);
+	    if (SSL_shutdown(closure->ssl) == 0)
+		SSL_shutdown(closure->ssl);
+	    SSL_free(closure->ssl);
+	}
+#endif
+	if (closure->sock != -1) {
+	    shutdown(closure->sock, SHUT_RDWR);
+	    close(closure->sock);
+	}
+	iolog_close_all(closure);
+	sudo_ev_free(closure->commit_ev);
+	sudo_ev_free(closure->read_ev);
+	sudo_ev_free(closure->write_ev);
+#if defined(HAVE_OPENSSL)
+	sudo_ev_free(closure->ssl_accept_ev);
+#endif
+	eventlog_free(closure->evlog);
+	free(closure->read_buf.data);
+	while ((buf = TAILQ_FIRST(&closure->write_bufs)) != NULL) {
+	    sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+		"discarding write buffer %p, len %u", buf, buf->len - buf->off);
+	    TAILQ_REMOVE(&closure->write_bufs, buf, entries);
+	    free(buf->data);
+	    free(buf);
+	}
+	while ((buf = TAILQ_FIRST(&closure->free_bufs)) != NULL) {
+	    TAILQ_REMOVE(&closure->free_bufs, buf, entries);
+	    free(buf->data);
+	    free(buf);
+	}
+	free(closure->journal_path);
+	if (closure->journal != NULL)
+	    fclose(closure->journal);
+	free(closure);
+
+	if (shutting_down && TAILQ_EMPTY(&connections))
+	    sudo_ev_loopbreak(evbase);
+    }
+
+    debug_return;
+}
+
+/*
+ * Allocate a new connection closure.
+ */
+struct connection_closure *
+connection_closure_alloc(int fd, bool tls, bool relay_only,
+    struct sudo_event_base *base)
+{
+    struct connection_closure *closure;
+    debug_decl(connection_closure_alloc, SUDO_DEBUG_UTIL);
+
+    if ((closure = calloc(1, sizeof(*closure))) == NULL)
+	debug_return_ptr(NULL);
+
+    closure->iolog_dir_fd = -1;
+    closure->sock = relay_only ? -1 : fd;
+    closure->evbase = base;
+    TAILQ_INIT(&closure->write_bufs);
+    TAILQ_INIT(&closure->free_bufs);
+
+    /* Use different message handlers depending on the operating mode. */
+    if (relay_only) {
+	closure->cms = &cms_relay;
+    } else if (logsrvd_conf_relay_store_first()) {
+	closure->store_first = true;
+	closure->cms = &cms_journal;
+    } else {
+	closure->cms = &cms_local;
+    }
+
+    TAILQ_INSERT_TAIL(&connections, closure, entries);
+
+    closure->read_buf.size = 64 * 1024;
+    closure->read_buf.data = malloc(closure->read_buf.size);
+    if (closure->read_buf.data == NULL)
+	goto bad;
+
+    closure->read_ev = sudo_ev_alloc(fd, SUDO_EV_READ|SUDO_EV_PERSIST,
+	client_msg_cb, closure);
+    if (closure->read_ev == NULL)
+	goto bad;
+
+    if (!relay_only) {
+	closure->write_ev = sudo_ev_alloc(fd, SUDO_EV_WRITE|SUDO_EV_PERSIST,
+	    server_msg_cb, closure);
+	if (closure->write_ev == NULL)
+	    goto bad;
+
+	closure->commit_ev = sudo_ev_alloc(-1, SUDO_EV_TIMEOUT,
+	    server_commit_cb, closure);
+	if (closure->commit_ev == NULL)
+	    goto bad;
+    }
+#if defined(HAVE_OPENSSL)
+    if (tls) {
+	closure->ssl_accept_ev = sudo_ev_alloc(fd, SUDO_EV_READ,
+	    tls_handshake_cb, closure);
+	if (closure->ssl_accept_ev == NULL)
+	    goto bad;
+    }
+#endif
+
+    debug_return_ptr(closure);
+bad:
+    connection_closure_free(closure);
+    debug_return_ptr(NULL);
+}
+
+/*
+ * Close the client connection when finished.
+ * If in store-and-forward mode, initiate a relay connection.
+ * Otherwise, free the connection closure, removing any events.
+ */
+void
+connection_close(struct connection_closure *closure)
+{
+    struct connection_closure *new_closure;
+    debug_decl(connection_close, SUDO_DEBUG_UTIL);
+
+    if (closure == NULL)
+	debug_return;
+
+    /* Final state should be FINISHED except on error. */
+    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+	"%s: closure %p, final state %d, relay_closure %p, "
+	"journal file %p, journal path %s", __func__, closure,
+	closure->state, closure->relay_closure, closure->journal,
+	closure->journal_path ? closure->journal_path : "");
+
+    /*
+     * If we finished a client connection in store-and-forward mode,
+     * create a new connection for the relay and replay the journal.
+     */
+    if (closure->store_first && closure->state == FINISHED &&
+	    closure->relay_closure == NULL && closure->journal != NULL) {
+	new_closure = connection_closure_alloc(fileno(closure->journal), false,
+	    true, closure->evbase);
+	if (new_closure != NULL) {
+	    /* Re-parent journal settings. */
+	    new_closure->journal = closure->journal;
+	    closure->journal = NULL;
+	    new_closure->journal_path = closure->journal_path;
+	    closure->journal_path = NULL;
+
+	    /* Connect to the first relay available asynchronously. */
+	    if (!connect_relay(new_closure)) {
+		sudo_warnx("%s", U_("unable to connect to relay"));
+		connection_closure_free(new_closure);
+	    }
+	}
+    }
+    if (closure->state == FINISHED && closure->journal_path != NULL) {
+	/* Journal relayed successfully, remove backing file. */
+	sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+	    "removing journal file %s", closure->journal_path);
+	unlink(closure->journal_path);
+
+	/* Process the next outgoing file (if any). */
+	logsrvd_queue_enable(0, closure->evbase);
+    }
+    connection_closure_free(closure);
+
+    debug_return;
+}
+
+struct connection_buffer *
+get_free_buf(size_t len, struct connection_closure *closure)
+{
+    struct connection_buffer *buf;
+    debug_decl(get_free_buf, SUDO_DEBUG_UTIL);
+
+    buf = TAILQ_FIRST(&closure->free_bufs);
+    if (buf != NULL) {
+        TAILQ_REMOVE(&closure->free_bufs, buf, entries);
+    } else {
+        if ((buf = calloc(1, sizeof(*buf))) == NULL) {
+	    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	    debug_return_ptr(NULL);
+	}
+    }
+
+    if (len > buf->size) {
+	free(buf->data);
+	buf->size = sudo_pow2_roundup(len);
+	if ((buf->data = malloc(buf->size)) == NULL) {
+	    sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+	    free(buf);
+	    buf = NULL;
+	}
+    }
+
+    debug_return_ptr(buf);
+}
+
+static bool
+fmt_server_message(struct connection_closure *closure, ServerMessage *msg)
+{
+    struct connection_buffer *buf = NULL;
+    uint32_t msg_len;
+    bool ret = false;
+    size_t len;
+    debug_decl(fmt_server_message, SUDO_DEBUG_UTIL);
+
+    len = server_message__get_packed_size(msg);
+    if (len > MESSAGE_SIZE_MAX) {
+	sudo_warnx(U_("server message too large: %zu"), len);
+        goto done;
+    }
+
+    /* Wire message size is used for length encoding, precedes message. */
+    msg_len = htonl((uint32_t)len);
+    len += sizeof(msg_len);
+
+    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+	"size + server message %zu bytes", len);
+
+    if ((buf = get_free_buf(len, closure)) == NULL) {
+	sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+	    "unable to allocate connection_buffer");
+        goto done;
+    }
+    memcpy(buf->data, &msg_len, sizeof(msg_len));
+    server_message__pack(msg, buf->data + sizeof(msg_len));
+    buf->len = len;
+    TAILQ_INSERT_TAIL(&closure->write_bufs, buf, entries);
+
+    ret = true;
+
+done:
+    debug_return_bool(ret);
+}
+
+static bool
+fmt_hello_message(struct connection_closure *closure)
+{
+    ServerMessage msg = SERVER_MESSAGE__INIT;
+    ServerHello hello = SERVER_HELLO__INIT;
+    debug_decl(fmt_hello_message, SUDO_DEBUG_UTIL);
+
+    /* TODO: implement redirect and servers array.  */
+    hello.server_id = (char *)server_id;
+    hello.subcommands = true;
+    msg.u.hello = &hello;
+    msg.type_case = SERVER_MESSAGE__TYPE_HELLO;
+
+    debug_return_bool(fmt_server_message(closure, &msg));
+}
+
+bool
+fmt_log_id_message(const char *id, struct connection_closure *closure)
+{
+    ServerMessage msg = SERVER_MESSAGE__INIT;
+    debug_decl(fmt_log_id_message, SUDO_DEBUG_UTIL);
+
+    msg.u.log_id = (char *)id;
+    msg.type_case = SERVER_MESSAGE__TYPE_LOG_ID;
+
+    debug_return_bool(fmt_server_message(closure, &msg));
+}
+
+static bool
+fmt_error_message(const char *errstr, struct connection_closure *closure)
+{
+    ServerMessage msg = SERVER_MESSAGE__INIT;
+    debug_decl(fmt_error_message, SUDO_DEBUG_UTIL);
+
+    msg.u.error = (char *)errstr;
+    msg.type_case = SERVER_MESSAGE__TYPE_ERROR;
+
+    debug_return_bool(fmt_server_message(closure, &msg));
+}
+
+/*
+ * Format a ServerMessage with the error string and add it to the write queue.
+ * Also sets the error flag state to true.
+ * Returns true if successfully scheduled, else false.
+ */
+bool
+schedule_error_message(const char *errstr, struct connection_closure *closure)
+{
+    bool ret = false;
+    debug_decl(schedule_error_message, SUDO_DEBUG_UTIL);
+
+    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+	"send error to client: %s", errstr ? errstr : "none");
+
+    /* Prevent further reads from the client, just write the error. */
+    sudo_ev_del(closure->evbase, closure->read_ev);
+
+    if (errstr == NULL || closure->error || closure->write_ev == NULL)
+	goto done;
+
+    /* Format error message and add to the write queue. */
+    if (!fmt_error_message(errstr, closure))
+	goto done;
+    if (sudo_ev_add(closure->evbase, closure->write_ev,
+	    logsrvd_conf_server_timeout(), true) == -1) {
+	sudo_warnx("%s", U_("unable to add event to queue"));
+	goto done;
+    }
+    ret = true;
+
+done:
+    closure->error = true;
+    debug_return_bool(ret);
+}
+
+/*
+ * AcceptMessage handler.
+ */
+static bool
+handle_accept(AcceptMessage *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+        closure->ipaddr;
+    bool ret;
+    debug_decl(handle_accept, SUDO_DEBUG_UTIL);
+
+    /* We can get an AcceptMessage for a sub-command during a session. */
+    if (closure->state == EXITED || closure->state == FINISHED) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->submit_time == NULL || msg->n_info_msgs == 0) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid AcceptMessage"));
+	closure->errstr = _("invalid AcceptMessage");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received AcceptMessage from %s",
+	__func__, source);
+
+    ret = closure->cms->accept(msg, buf, len, closure);
+    if (ret && closure->state == INITIAL) {
+	if (msg->expect_iobufs)
+	    closure->log_io = true;
+	closure->state = RUNNING;
+    }
+    debug_return_bool(ret);
+}
+
+/*
+ * RejectMessage handler.
+ */
+static bool
+handle_reject(RejectMessage *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+        closure->ipaddr;
+    bool ret;
+    debug_decl(handle_reject, SUDO_DEBUG_UTIL);
+
+    /* We can get a RejectMessage for a sub-command during a session. */
+    if (closure->state == EXITED || closure->state == FINISHED) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->submit_time == NULL || msg->n_info_msgs == 0) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid RejectMessage"));
+	closure->errstr = _("invalid RejectMessage");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received RejectMessage from %s",
+	__func__, source);
+
+    ret = closure->cms->reject(msg, buf, len, closure);
+    if (ret && closure->state == INITIAL) {
+	closure->state = FINISHED;
+    }
+
+    debug_return_bool(ret);
+}
+
+static bool
+handle_exit(ExitMessage *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    bool ret;
+    debug_decl(handle_exit, SUDO_DEBUG_UTIL);
+
+    if (closure->state != RUNNING) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->run_time == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid ExitMessage"));
+	closure->errstr = _("invalid ExitMessage");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received ExitMessage from %s",
+	source, __func__);
+
+    ret = closure->cms->exit(msg, buf, len, closure);
+    if (ret) {
+	if (sudo_timespecisset(&closure->elapsed_time)) {
+	    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: elapsed time: [%lld, %ld]",
+		__func__, (long long)closure->elapsed_time.tv_sec,
+		closure->elapsed_time.tv_nsec);
+	}
+
+	if (closure->log_io) {
+	    /* Command exited, client waiting for final commit point. */
+	    closure->state = EXITED;
+
+	    /* Relay host will send the final commit point. */
+	    if (closure->relay_closure == NULL) {
+		struct timespec tv = { 0, 0 };
+		if (sudo_ev_add(closure->evbase, closure->commit_ev, &tv, false) == -1) {
+		    sudo_warnx("%s", U_("unable to add event to queue"));
+		    ret = false;
+		}
+	    }
+	} else {
+	    /* No commit point to send to client, we are finished. */
+	    closure->state = FINISHED;
+	}
+    }
+    sudo_ev_del(closure->evbase, closure->read_ev);
+
+    debug_return_bool(ret);
+}
+
+static bool
+handle_restart(RestartMessage *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    bool ret = true;
+    debug_decl(handle_restart, SUDO_DEBUG_UTIL);
+
+    if (closure->state != INITIAL) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->log_id == NULL || msg->resume_point == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid RestartMessage"));
+	closure->errstr = _("invalid RestartMessage");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO,
+	"%s: received RestartMessage for %s from %s", __func__, msg->log_id,
+	source);
+
+    /* Only I/O logs are restartable. */
+    closure->log_io = true;
+
+    if (closure->cms->restart(msg, buf, len, closure)) {
+	/* Successfully restarted. */
+	closure->state = RUNNING;
+    } else {
+	/* Report error to client before closing the connection. */
+	sudo_debug_printf(SUDO_DEBUG_WARN, "%s: unable to restart I/O log",
+	    __func__);
+	if (!schedule_error_message(closure->errstr, closure))
+	    ret = false;
+    }
+
+    debug_return_bool(ret);
+}
+
+static bool
+handle_alert(AlertMessage *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    debug_decl(handle_alert, SUDO_DEBUG_UTIL);
+
+    /* Check that message is valid. */
+    if (msg->alert_time == NULL || msg->reason == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid AlertMessage"));
+	closure->errstr = _("invalid AlertMessage");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received AlertMessage from %s",
+	source, __func__);
+
+    debug_return_bool(closure->cms->alert(msg, buf, len, closure));
+}
+
+/* Enable a commit event if not relaying and it is not already pending. */
+static bool
+enable_commit(struct connection_closure *closure)
+{
+    debug_decl(enable_commit, SUDO_DEBUG_UTIL);
+
+    if (closure->relay_closure == NULL) {
+	if (!ISSET(closure->commit_ev->flags, SUDO_EVQ_INSERTED)) {
+	    struct timespec tv = { ACK_FREQUENCY, 0 };
+	    if (sudo_ev_add(closure->evbase, closure->commit_ev, &tv, false) == -1) {
+		sudo_warnx("%s", U_("unable to add event to queue"));
+		debug_return_bool(false);
+	    }
+	}
+    }
+    debug_return_bool(true);
+}
+
+static bool
+handle_iobuf(int iofd, IoBuffer *iobuf, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    debug_decl(handle_iobuf, SUDO_DEBUG_UTIL);
+
+    if (closure->state != RUNNING) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+    if (!closure->log_io) {
+	sudo_warnx(U_("%s: unexpected IoBuffer"), source);
+	closure->errstr = _("protocol error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (iobuf->delay == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid IoBuffer"));
+	closure->errstr = _("invalid IoBuffer");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received IoBuffer from %s",
+	source, __func__);
+
+    if (!closure->cms->iobuf(iofd, iobuf, buf, len, closure))
+	debug_return_bool(false);
+    if (!enable_commit(closure))
+	debug_return_bool(false);
+
+    debug_return_bool(true);
+}
+
+static bool
+handle_winsize(ChangeWindowSize *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    debug_decl(handle_winsize, SUDO_DEBUG_UTIL);
+
+    if (closure->state != RUNNING) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+    if (!closure->log_io) {
+	sudo_warnx(U_("%s: unexpected IoBuffer"), source);
+	closure->errstr = _("protocol error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->delay == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid ChangeWindowSize"));
+	closure->errstr = _("invalid ChangeWindowSize");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received ChangeWindowSize from %s",
+	source, __func__);
+
+    if (!closure->cms->winsize(msg, buf, len, closure))
+	debug_return_bool(false);
+    if (!enable_commit(closure))
+	debug_return_bool(false);
+
+    debug_return_bool(true);
+}
+
+static bool
+handle_suspend(CommandSuspend *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    debug_decl(handle_syspend, SUDO_DEBUG_UTIL);
+
+    if (closure->state != RUNNING) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+    if (!closure->log_io) {
+	sudo_warnx(U_("%s: unexpected IoBuffer"), source);
+	closure->errstr = _("protocol error");
+	debug_return_bool(false);
+    }
+
+    /* Check that message is valid. */
+    if (msg->delay == NULL || msg->signal == NULL) {
+	sudo_warnx(U_("%s: %s"), source, U_("invalid CommandSuspend"));
+	closure->errstr = _("invalid CommandSuspend");
+	debug_return_bool(false);
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received CommandSuspend from %s",
+	source, __func__);
+
+    if (!closure->cms->suspend(msg, buf, len, closure))
+	debug_return_bool(false);
+    if (!enable_commit(closure))
+	debug_return_bool(false);
+
+    debug_return_bool(true);
+}
+
+static bool
+handle_client_hello(ClientHello *msg, uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+	closure->ipaddr;
+    debug_decl(handle_client_hello, SUDO_DEBUG_UTIL);
+
+    if (closure->state != INITIAL) {
+	sudo_warnx(U_("unexpected state %d for %s"), closure->state, source);
+	closure->errstr = _("state machine error");
+	debug_return_bool(false);
+    }
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received ClientHello",
+	__func__);
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: client ID %s",
+	__func__, msg->client_id ? msg->client_id : "unknown");
+
+    debug_return_bool(true);
+}
+
+static bool
+handle_client_message(uint8_t *buf, size_t len,
+    struct connection_closure *closure)
+{
+    const char *source = closure->journal_path ? closure->journal_path :
+        closure->ipaddr;
+    ClientMessage *msg;
+    bool ret = false;
+    debug_decl(handle_client_message, SUDO_DEBUG_UTIL);
+
+    /* TODO: can we extract type_case without unpacking for relay case? */
+    msg = client_message__unpack(NULL, len, buf);
+    if (msg == NULL) {
+	sudo_warnx(U_("unable to unpack %s size %zu"), "ClientMessage", len);
+	debug_return_bool(false);
+    }
+
+    switch (msg->type_case) {
+    case CLIENT_MESSAGE__TYPE_ACCEPT_MSG:
+	ret = handle_accept(msg->u.accept_msg, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_REJECT_MSG:
+	ret = handle_reject(msg->u.reject_msg, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_EXIT_MSG:
+	ret = handle_exit(msg->u.exit_msg, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_RESTART_MSG:
+	ret = handle_restart(msg->u.restart_msg, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_ALERT_MSG:
+	ret = handle_alert(msg->u.alert_msg, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_TTYIN_BUF:
+	ret = handle_iobuf(IOFD_TTYIN, msg->u.ttyin_buf, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_TTYOUT_BUF:
+	ret = handle_iobuf(IOFD_TTYOUT, msg->u.ttyout_buf, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_STDIN_BUF:
+	ret = handle_iobuf(IOFD_STDIN, msg->u.stdin_buf, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_STDOUT_BUF:
+	ret = handle_iobuf(IOFD_STDOUT, msg->u.stdout_buf, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_STDERR_BUF:
+	ret = handle_iobuf(IOFD_STDERR, msg->u.stderr_buf, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_WINSIZE_EVENT:
+	ret = handle_winsize(msg->u.winsize_event, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_SUSPEND_EVENT:
+	ret = handle_suspend(msg->u.suspend_event, buf, len, closure);
+	break;
+    case CLIENT_MESSAGE__TYPE_HELLO_MSG:
+	ret = handle_client_hello(msg->u.hello_msg, buf, len, closure);
+	break;
+    default:
+	sudo_warnx(U_("unexpected type_case value %d in %s from %s"),
+	    msg->type_case, "ClientMessage", source);
+	closure->errstr = _("unrecognized ClientMessage type");
+	break;
+    }
+    client_message__free_unpacked(msg, NULL);
+
+    debug_return_bool(ret);
+}
+
+static void
+shutdown_cb(int unused, int what, void *v)
+{
+    struct sudo_event_base *base = v;
+    debug_decl(shutdown_cb, SUDO_DEBUG_UTIL);
+
+    sudo_ev_loopbreak(base);
+
+    debug_return;
+}
+
+/*
+ * Shut down active client connections if any, or exit immediately.
+ */
+static void
+server_shutdown(struct sudo_event_base *base)
+{
+    struct connection_closure *closure, *next;
+    struct sudo_event *ev;
+    struct timespec tv = { 0, 0 };
+    debug_decl(server_shutdown, SUDO_DEBUG_UTIL);
+
+    if (TAILQ_EMPTY(&connections)) {
+	sudo_ev_loopbreak(base);
+	debug_return;
+    }
+
+    TAILQ_FOREACH_SAFE(closure, &connections, entries, next) {
+	closure->state = SHUTDOWN;
+	sudo_ev_del(base, closure->read_ev);
+	if (closure->relay_closure != NULL) {
+	    /* Connection being relayed, check for pending I/O. */
+	    relay_shutdown(closure);
+	} else if (closure->log_io) {
+	    /* Schedule final commit point for the connection. */
+	    if (sudo_ev_add(base, closure->commit_ev, &tv, false) == -1) {
+		sudo_warnx("%s", U_("unable to add event to queue"));
+	    }
+	} else {
+	    /* No commit point, close connection immediately. */
+	    connection_close(closure);
+	}
+    }
+
+    if (!TAILQ_EMPTY(&connections)) {
+	/* We need a timed event to exit even if clients time out. */
+	ev = sudo_ev_alloc(-1, SUDO_EV_TIMEOUT, shutdown_cb, base);
+	if (ev != NULL) {
+	    tv.tv_sec = SHUTDOWN_TIMEO;
+	    if (sudo_ev_add(base, ev, &tv, false) == -1) {
+		sudo_warnx("%s", U_("unable to add event to queue"));
+	    }
+	}
+    }
+
+    debug_return;
+}
+
+/*
+ * Send a server message to the client.
+ */
+static void
+server_msg_cb(int fd, int what, void *v)
+{
+    struct connection_closure *closure = v;
+    struct connection_buffer *buf;
+    ssize_t nwritten;
+    debug_decl(server_msg_cb, SUDO_DEBUG_UTIL);
+
+    /* For TLS we may need to write as part of SSL_read(). */
+    if (closure->read_instead_of_write) {
+	closure->read_instead_of_write = false;
+	/* Delete write event if it was only due to SSL_read(). */
+	if (closure->temporary_write_event) {
+	    closure->temporary_write_event = false;
+	    sudo_ev_del(closure->evbase, closure->write_ev);
+	}
+	client_msg_cb(fd, what, v);
+	debug_return;
+    }
+
+    if (what == SUDO_EV_TIMEOUT) {
+	sudo_warnx(U_("timed out writing to client %s"), closure->ipaddr);
+        goto finished;
+    }
+
+    if ((buf = TAILQ_FIRST(&closure->write_bufs)) == NULL) {
+	sudo_warnx(U_("missing write buffer for client %s"), closure->ipaddr);
+        goto finished;
+    }
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: sending %u bytes to client (%s)",
+	__func__, buf->len - buf->off, closure->ipaddr);
+
+#if defined(HAVE_OPENSSL)
+    if (closure->ssl != NULL) {
+        nwritten = SSL_write(closure->ssl, buf->data + buf->off,
+	    buf->len - buf->off);
+        if (nwritten <= 0) {
+	    const char *errstr;
+            int err = SSL_get_error(closure->ssl, nwritten);
+            switch (err) {
+                case SSL_ERROR_WANT_READ:
+		    /* ssl wants to read, read event always active */
+		    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+			"SSL_write returns SSL_ERROR_WANT_READ");
+		    /* Redirect persistent read event to finish SSL_write() */
+		    closure->write_instead_of_read = true;
+                    debug_return;
+                case SSL_ERROR_WANT_WRITE:
+		    /* ssl wants to write more, write event remains active */
+		    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+			"SSL_write returns SSL_ERROR_WANT_WRITE");
+                    debug_return;
+		case SSL_ERROR_SYSCALL:
+		    sudo_warn("%s: SSL_write", closure->ipaddr);
+		    goto finished;
+                default:
+		    errstr = ERR_reason_error_string(ERR_get_error());
+		    sudo_warnx("%s: SSL_write: %s", closure->ipaddr,
+			errstr ? errstr : strerror(errno));
+                    goto finished;
+            }
+        }
+    } else
+#endif
+    {
+	nwritten = write(fd, buf->data + buf->off, buf->len - buf->off);
+    }
+
+    if (nwritten == -1) {
+	if (errno == EAGAIN || errno == EINTR)
+	    debug_return;
+	sudo_warn("%s: write", closure->ipaddr);
+	goto finished;
+    }
+    buf->off += nwritten;
+
+    if (buf->off == buf->len) {
+	/* sent entire message, move buf to free list */
+	sudo_debug_printf(SUDO_DEBUG_INFO,
+	    "%s: finished sending %u bytes to client", __func__, buf->len);
+	buf->off = 0;
+	buf->len = 0;
+	TAILQ_REMOVE(&closure->write_bufs, buf, entries);
+	TAILQ_INSERT_TAIL(&closure->free_bufs, buf, entries);
+	if (TAILQ_EMPTY(&closure->write_bufs)) {
+	    /* Write queue empty, check state. */
+	    sudo_ev_del(closure->evbase, closure->write_ev);
+	    if (closure->error || closure->state == FINISHED ||
+		    closure->state == SHUTDOWN)
+		goto finished;
+	}
+    }
+    debug_return;
+
+finished:
+    connection_close(closure);
+    debug_return;
+}
+
+/*
+ * Receive client message(s).
+ */
+static void
+client_msg_cb(int fd, int what, void *v)
+{
+    struct connection_closure *closure = v;
+    struct connection_buffer *buf = &closure->read_buf;
+    const char *source = closure->journal_path ? closure->journal_path :
+        closure->ipaddr;
+    uint32_t msg_len;
+    ssize_t nread;
+    debug_decl(client_msg_cb, SUDO_DEBUG_UTIL);
+
+    /* For TLS we may need to read as part of SSL_write(). */
+    if (closure->write_instead_of_read) {
+	closure->write_instead_of_read = false;
+	server_msg_cb(fd, what, v);
+	debug_return;
+    }
+
+    if (what == SUDO_EV_TIMEOUT) {
+	sudo_warnx(U_("timed out reading from client %s"), closure->ipaddr);
+        goto close_connection;
+    }
+
+#if defined(HAVE_OPENSSL)
+    if (closure->ssl != NULL) {
+       nread = SSL_read(closure->ssl, buf->data + buf->len, buf->size);
+        if (nread <= 0) {
+	    const char *errstr;
+            int err = SSL_get_error(closure->ssl, nread);
+            switch (err) {
+		case SSL_ERROR_ZERO_RETURN:
+		    /* ssl connection shutdown cleanly */
+		    nread = 0;
+		    break;
+                case SSL_ERROR_WANT_READ:
+		    /* ssl wants to read more, read event is always active */
+		    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+			"SSL_read returns SSL_ERROR_WANT_READ");
+		    /* Read event is always active. */
+                    debug_return;
+                case SSL_ERROR_WANT_WRITE:
+		    /* ssl wants to write, schedule a write if not pending */
+		    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+			"SSL_read returns SSL_ERROR_WANT_WRITE");
+		    if (!sudo_ev_pending(closure->write_ev, SUDO_EV_WRITE, NULL)) {
+			/* Enable a temporary write event. */
+			if (sudo_ev_add(closure->evbase, closure->write_ev,
+			    logsrvd_conf_server_timeout(), false) == -1) {
+			    sudo_warnx("%s", U_("unable to add event to queue"));
+			    closure->errstr = _("unable to allocate memory");
+			    goto send_error;
+			}
+			closure->temporary_write_event = true;
+		    }
+		    /* Redirect write event to finish SSL_read() */
+		    closure->read_instead_of_write = true;
+                    debug_return;
+		case SSL_ERROR_SYSCALL:
+		    if (nread == 0) {
+			/* EOF, handled below */
+			sudo_warnx(U_("EOF from %s without proper TLS shutdown"),
+			    closure->ipaddr);
+			break;
+		    }
+		    sudo_warn("%s: SSL_read", closure->ipaddr);
+                    goto close_connection;
+                default:
+		    errstr = ERR_reason_error_string(ERR_get_error());
+		    sudo_warnx("%s: SSL_read: %s", closure->ipaddr,
+			errstr ? errstr : strerror(errno));
+		    goto close_connection;
+            }
+        }
+    } else
+#endif
+    {
+        nread = read(fd, buf->data + buf->len, buf->size - buf->len);
+    }
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s: received %zd bytes from client %s",
+	__func__, nread, closure->ipaddr);
+    switch (nread) {
+    case -1:
+	if (errno == EAGAIN || errno == EINTR)
+	    debug_return;
+	sudo_warn("%s: read", closure->ipaddr);
+	goto close_connection;
+    case 0:
+        if (closure->state != FINISHED) {
+            sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,
+                "unexpected EOF");
+        }
+        goto close_connection;
+    default:
+	break;
+    }
+    buf->len += nread;
+
+    while (buf->len - buf->off >= sizeof(msg_len)) {
+	/* Read wire message size (uint32_t in network byte order). */
+	memcpy(&msg_len, buf->data + buf->off, sizeof(msg_len));
+	msg_len = ntohl(msg_len);
+
+	if (msg_len > MESSAGE_SIZE_MAX) {
+	    sudo_warnx(U_("client message too large: %zu"), (size_t)msg_len);
+	    closure->errstr = _("client message too large");
+	    goto send_error;
+	}
+
+	if (msg_len + sizeof(msg_len) > buf->len - buf->off) {
+	    /* Incomplete message, we'll read the rest next time. */
+	    if (!expand_buf(buf, msg_len + sizeof(msg_len))) {
+		closure->errstr = _("unable to allocate memory");
+		goto send_error;
+	    }
+	    debug_return;
+	}
+
+	/* Parse ClientMessage (could be zero bytes). */
+	sudo_debug_printf(SUDO_DEBUG_INFO,
+	    "%s: parsing ClientMessage, size %u", __func__, msg_len);
+	buf->off += sizeof(msg_len);
+	if (!handle_client_message(buf->data + buf->off, msg_len, closure)) {
+	    sudo_warnx(U_("%s: %s"), source, U_("invalid ClientMessage"));
+	    closure->errstr = _("invalid ClientMessage");
+	    goto send_error;
+	}
+	buf->off += msg_len;
+    }
+    buf->len -= buf->off;
+    buf->off = 0;
+
+    if (closure->state == FINISHED)
+	goto close_connection;
+
+    debug_return;
+
+send_error:
+    /*
+     * Try to send client an error message before closing the connection.
+     */
+    if (!schedule_error_message(closure->errstr, closure))
+	goto close_connection;
+    debug_return;
+
+close_connection:
+    connection_close(closure);
+    debug_return;
+}
+
+/*
+ * Format and schedule a commit_point message.
+ */
+bool
+schedule_commit_point(TimeSpec *commit_point,
+    struct connection_closure *closure)
+{
+    debug_decl(schedule_commit_point, SUDO_DEBUG_UTIL);
+
+    if (closure->write_ev != NULL) {
+	/* Send an acknowledgement of what we've committed to disk. */
+	ServerMessage msg = SERVER_MESSAGE__INIT;
+	msg.u.commit_point = commit_point;
+	msg.type_case = SERVER_MESSAGE__TYPE_COMMIT_POINT;
+
+	sudo_debug_printf(SUDO_DEBUG_INFO,
+	    "%s: sending commit point [%lld, %ld]", __func__,
+	    (long long)commit_point->tv_sec, (long)commit_point->tv_nsec);
+
+	if (!fmt_server_message(closure, &msg))
+	    goto bad;
+	if (sudo_ev_add(closure->evbase, closure->write_ev,
+	    logsrvd_conf_server_timeout(), false) == -1) {
+	    sudo_warnx("%s", U_("unable to add event to queue"));
+	    goto bad;
+	}
+    }
+
+    if (closure->state == EXITED)
+	closure->state = FINISHED;
+    debug_return_bool(true);
+bad:
+    debug_return_bool(false);
+}
+
+/*
+ * Time-based event that fires periodically to report to the client
+ * what has been committed to disk.
+ */
+static void
+server_commit_cb(int unused, int what, void *v)
+{
+    struct connection_closure *closure = v;
+    TimeSpec commit_point = TIME_SPEC__INIT;
+    debug_decl(server_commit_cb, SUDO_DEBUG_UTIL);
+
+    /* Flush I/O logs before sending commit point if needed. */
+    if (!iolog_get_flush())
+	iolog_flush_all(closure);
+
+    commit_point.tv_sec = closure->elapsed_time.tv_sec;
+    commit_point.tv_nsec = closure->elapsed_time.tv_nsec;
+    if (!schedule_commit_point(&commit_point, closure))
+	connection_close(closure);
+
+    debug_return;
+}
+
+/*
+ * Begin the sudo logserver protocol.
+ * When we enter the event loop the ServerHello message will be written
+ * and any pending ClientMessage will be read.
+ */
+bool
+start_protocol(struct connection_closure *closure)
+{
+    const struct timespec *timeout = logsrvd_conf_server_timeout();
+    debug_decl(start_protocol, SUDO_DEBUG_UTIL);
+
+    if (closure->relay_closure != NULL && closure->relay_closure->relays != NULL) {
+	/* No longer need the stashed relays list. */
+	address_list_delref(closure->relay_closure->relays);
+	closure->relay_closure->relays = NULL;
+	closure->relay_closure->relay_addr = NULL;
+    }
+
+    /* When replaying a journal there is no write event. */
+    if (closure->write_ev != NULL) {
+	if (!fmt_hello_message(closure))
+	    debug_return_bool(false);
+
+	if (sudo_ev_add(closure->evbase, closure->write_ev, timeout, false) == -1)
+	    debug_return_bool(false);
+    }
+
+    /* No read timeout, client messages may happen at arbitrary times. */
+    if (sudo_ev_add(closure->evbase, closure->read_ev, NULL, false) == -1)
+	debug_return_bool(false);
+
+    debug_return_bool(true);
+}
+
+#if defined(HAVE_OPENSSL)
+static int
+verify_peer_identity(int preverify_ok, X509_STORE_CTX *ctx)
+{
+    HostnameValidationResult result;
+    struct connection_closure *closure;
+    SSL *ssl;
+    X509 *current_cert;
+    X509 *peer_cert;
+    debug_decl(verify_peer_identity, SUDO_DEBUG_UTIL);
+
+    /* if pre-verification of the cert failed, just propagate that result back */
+    if (preverify_ok != 1) {
+        debug_return_int(0);
+    }
+
+    /* since this callback is called for each cert in the chain,
+     * check that current cert is the peer's certificate
+     */
+    current_cert = X509_STORE_CTX_get_current_cert(ctx);
+    peer_cert = X509_STORE_CTX_get0_cert(ctx);
+
+    if (current_cert != peer_cert) {
+        debug_return_int(1);
+    }
+
+    /* read out the attached object (closure) from the ssl connection object */
+    ssl = X509_STORE_CTX_get_ex_data(ctx, SSL_get_ex_data_X509_STORE_CTX_idx());
+    closure = (struct connection_closure *)SSL_get_ex_data(ssl, 1);
+
+    result = validate_hostname(peer_cert, closure->ipaddr, closure->ipaddr, 1);
+
+    switch(result)
+    {
+        case MatchFound:
+            debug_return_int(1);
+        default:
+            sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+                "hostname validation failed");
+            debug_return_int(0);
+    }
+}
+
+/*
+ * Set the TLS verify callback to verify_peer_identity().
+ */
+static void
+set_tls_verify_peer(void)
+{
+    SSL_CTX *server_ctx = logsrvd_server_tls_ctx();
+    SSL_CTX *relay_ctx = logsrvd_relay_tls_ctx();
+    debug_decl(set_tls_verify_peer, SUDO_DEBUG_UTIL);
+
+    if (server_ctx != NULL && logsrvd_conf_server_tls_check_peer()) {
+	/* Verify server cert during the handshake. */
+	SSL_CTX_set_verify(server_ctx,
+	    SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
+	    verify_peer_identity);
+    }
+    if (relay_ctx != NULL && logsrvd_conf_relay_tls_check_peer()) {
+	/* Verify relay cert during the handshake. */
+	SSL_CTX_set_verify(relay_ctx,
+	    SSL_VERIFY_PEER|SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
+	    verify_peer_identity);
+    }
+
+    debug_return;
+}
+
+static void
+tls_handshake_cb(int fd, int what, void *v)
+{
+    struct connection_closure *closure = v;
+    const char *errstr;
+    int err, handshake_status;
+    debug_decl(tls_handshake_cb, SUDO_DEBUG_UTIL);
+
+    if (what == SUDO_EV_TIMEOUT) {
+	sudo_warnx("TLS handshake with %s timed out", closure->ipaddr);
+        goto bad;
+    }
+
+    handshake_status = SSL_accept(closure->ssl);
+    err = SSL_get_error(closure->ssl, handshake_status);
+    switch (err) {
+        case SSL_ERROR_NONE:
+	    /* ssl handshake was successful */
+	    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+		"TLS handshake successful");
+            break;
+        case SSL_ERROR_WANT_READ:
+	    /* ssl handshake is ongoing, re-schedule the SSL_accept() call */
+	    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+		"SSL_accept returns SSL_ERROR_WANT_READ");
+	    if (what != SUDO_EV_READ) {
+		if (sudo_ev_set(closure->ssl_accept_ev, closure->sock,
+			SUDO_EV_READ, tls_handshake_cb, closure) == -1) {
+		    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+			"unable to set ssl_accept_ev to SUDO_EV_READ");
+		    goto bad;
+		}
+	    }
+            if (sudo_ev_add(closure->evbase, closure->ssl_accept_ev,
+                logsrvd_conf_server_timeout(), false) == -1) {
+		sudo_warnx("%s", U_("unable to add event to queue"));
+                goto bad;
+            }
+            debug_return;
+        case SSL_ERROR_WANT_WRITE:
+	    /* ssl handshake is ongoing, re-schedule the SSL_accept() call */
+	    sudo_debug_printf(SUDO_DEBUG_NOTICE|SUDO_DEBUG_LINENO,
+		"SSL_accept returns SSL_ERROR_WANT_WRITE");
+	    if (what != SUDO_EV_WRITE) {
+		if (sudo_ev_set(closure->ssl_accept_ev, closure->sock,
+			SUDO_EV_WRITE, tls_handshake_cb, closure) == -1) {
+		    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+			"unable to set ssl_accept_ev to SUDO_EV_WRITE");
+		    goto bad;
+		}
+	    }
+            if (sudo_ev_add(closure->evbase, closure->ssl_accept_ev,
+		    logsrvd_conf_server_timeout(), false) == -1) {
+		sudo_warnx("%s", U_("unable to add event to queue"));
+                goto bad;
+            }
+            debug_return;
+	case SSL_ERROR_SYSCALL:
+	    sudo_warn("%s: SSL_accept", closure->ipaddr);
+            goto bad;
+        default:
+	    errstr = ERR_reason_error_string(ERR_get_error());
+	    sudo_warnx("%s: SSL_accept: %s", closure->ipaddr,
+		errstr ? errstr : strerror(errno));
+            goto bad;
+    }
+
+    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+        "TLS version: %s, negotiated cipher suite: %s",
+        SSL_get_version(closure->ssl),
+        SSL_get_cipher(closure->ssl));
+
+    /* Start the actual protocol now that the TLS handshake is complete. */
+    if (!TAILQ_EMPTY(logsrvd_conf_relay_address()) && !closure->store_first) {
+	if (!connect_relay(closure))
+	    goto bad;
+    } else {
+	if (!start_protocol(closure))
+	    goto bad;
+    }
+
+    debug_return;
+bad:
+    connection_close(closure);
+    debug_return;
+}
+#endif /* HAVE_OPENSSL */
+
+/*
+ * New connection.
+ * Allocate a connection closure and optionally perform TLS handshake.
+ */
+static bool
+new_connection(int sock, bool tls, const union sockaddr_union *sa_un,
+    struct sudo_event_base *evbase)
+{
+    struct connection_closure *closure;
+    debug_decl(new_connection, SUDO_DEBUG_UTIL);
+
+    if ((closure = connection_closure_alloc(sock, tls, false, evbase)) == NULL)
+	goto bad;
+
+    /* store the peer's IP address in the closure object */
+    if (sa_un->sa.sa_family == AF_INET) {
+        inet_ntop(AF_INET, &sa_un->sin.sin_addr, closure->ipaddr,
+            sizeof(closure->ipaddr));
+#ifdef HAVE_STRUCT_IN6_ADDR
+    } else if (sa_un->sa.sa_family == AF_INET6) {
+        inet_ntop(AF_INET6, &sa_un->sin6.sin6_addr, closure->ipaddr,
+            sizeof(closure->ipaddr));
+#endif /* HAVE_STRUCT_IN6_ADDR */
+    } else {
+	errno = EAFNOSUPPORT;
+        sudo_warn("%s", U_("unable to get remote IP addr"));
+        goto bad;
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
+	"connection from %s", closure->ipaddr);
+
+#if defined(HAVE_OPENSSL)
+    /* If TLS is enabled, perform the TLS handshake first. */
+    if (tls) {
+	const char *errstr;
+
+        /* Create the SSL object for the closure and attach it to the socket */
+        if ((closure->ssl = SSL_new(logsrvd_server_tls_ctx())) == NULL) {
+	    errstr = ERR_reason_error_string(ERR_get_error());
+	    sudo_warnx(U_("%s: %s"), "SSL_new",
+		errstr ? errstr : strerror(errno));
+            goto bad;
+        }
+
+        if (SSL_set_fd(closure->ssl, closure->sock) != 1) {
+	    errstr = ERR_reason_error_string(ERR_get_error());
+	    sudo_warnx(U_("%s: %s"), "SSL_set_fd",
+		errstr ? errstr : strerror(errno));
+            goto bad;
+        }
+
+        /* attach the closure object to the ssl connection object to make it
+        available during hostname matching
+        */
+        if (SSL_set_ex_data(closure->ssl, 1, closure) <= 0) {
+	    errstr = ERR_reason_error_string(ERR_get_error());
+            sudo_warnx(U_("Unable to attach user data to the ssl object: %s"),
+		errstr ? errstr : strerror(errno));
+            goto bad;
+        }
+
+        /* Enable SSL_accept to begin handshake with client. */
+        if (sudo_ev_add(evbase, closure->ssl_accept_ev,
+		logsrvd_conf_server_timeout(), false) == -1) {
+	    sudo_warnx("%s", U_("unable to add event to queue"));
+            goto bad;
+        }
+    }
+#endif
+    /* If no TLS handshake, start the protocol immediately. */
+    if (!tls) {
+	if (!TAILQ_EMPTY(logsrvd_conf_relay_address()) && !closure->store_first) {
+	    if (!connect_relay(closure))
+		goto bad;
+	} else {
+	    if (!start_protocol(closure))
+		goto bad;
+	}
+    }
+
+    debug_return_bool(true);
+bad:
+    connection_close(closure);
+    debug_return_bool(false);
+}
+
+static int
+create_listener(struct server_address *addr)
+{
+    int flags, on, sock;
+    const char *family = "inet4";
+    debug_decl(create_listener, SUDO_DEBUG_UTIL);
+
+    if ((sock = socket(addr->sa_un.sa.sa_family, SOCK_STREAM, 0)) == -1) {
+	sudo_warn("socket");
+	goto bad;
+    }
+    on = 1;
+#ifdef HAVE_STRUCT_IN6_ADDR
+    if (addr->sa_un.sa.sa_family == AF_INET6) {
+	family = "inet6";
+# ifdef IPV6_V6ONLY
+	/* Disable IPv4-mapped IPv6 addresses. */
+	if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof(on)) == -1)
+	    sudo_warn("IPV6_V6ONLY");
+# endif
+    }
+#endif
+    if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)
+	sudo_warn("SO_REUSEADDR");
+    if (bind(sock, &addr->sa_un.sa, addr->sa_size) == -1) {
+	/* TODO: only warn once for IPv4 and IPv6 or disambiguate */
+	sudo_warn("%s (%s)", addr->sa_str, family);
+	goto bad;
+    }
+    if (listen(sock, SOMAXCONN) == -1) {
+	sudo_warn("listen");
+	goto bad;
+    }
+    flags = fcntl(sock, F_GETFL, 0);
+    if (flags == -1 || fcntl(sock, F_SETFL, flags | O_NONBLOCK) == -1) {
+	sudo_warn("fcntl(O_NONBLOCK)");
+	goto bad;
+    }
+    sudo_debug_printf(SUDO_DEBUG_INFO, "listening on %s (%s)", addr->sa_str,
+	family);
+
+    debug_return_int(sock);
+bad:
+    if (sock != -1)
+	close(sock);
+    debug_return_int(-1);
+}
+
+static void
+listener_cb(int fd, int what, void *v)
+{
+    struct listener *l = v;
+    struct sudo_event_base *evbase = sudo_ev_get_base(l->ev);
+    union sockaddr_union sa_un;
+    socklen_t salen = sizeof(sa_un);
+    int sock;
+    debug_decl(listener_cb, SUDO_DEBUG_UTIL);
+
+    memset(&sa_un, 0, sizeof(sa_un));
+    sock = accept(fd, &sa_un.sa, &salen);
+    if (sock != -1) {
+	if (logsrvd_conf_server_tcp_keepalive()) {
+	    int keepalive = 1;
+	    if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, &keepalive,
+		    sizeof(keepalive)) == -1) {
+		sudo_warn("SO_KEEPALIVE");
+	    }
+	}
+	if (!new_connection(sock, l->tls, &sa_un, evbase)) {
+	    /* TODO: pause accepting on ENOMEM */
+	    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
+		"unable to start new connection");
+	}
+    } else {
+	if (errno == EAGAIN || errno == EINTR)
+	    debug_return;
+	/* TODO: pause accepting on ENFILE and EMFILE */
+	sudo_warn("accept");
+    }
+
+    debug_return;
+}
+
+static bool
+register_listener(struct server_address *addr, struct sudo_event_base *evbase)
+{
+    struct listener *l;
+    int sock;
+    debug_decl(register_listener, SUDO_DEBUG_UTIL);
+
+    sock = create_listener(addr);
+    if (sock == -1)
+	debug_return_bool(false);
+
+    /* TODO: make non-fatal */
+    if ((l = malloc(sizeof(*l))) == NULL)
+	sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    l->sock = sock;
+    l->tls = addr->tls;
+    l->ev = sudo_ev_alloc(sock, SUDO_EV_READ|SUDO_EV_PERSIST, listener_cb, l);
+    if (l->ev == NULL)
+	sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    if (sudo_ev_add(evbase, l->ev, NULL, false) == -1)
+	sudo_fatal("%s", U_("unable to add event to queue"));
+    TAILQ_INSERT_TAIL(&listeners, l, entries);
+
+    debug_return_bool(true);
+}
+
+/*
+ * Register listeners and set the TLS verify callback.
+ */
+static bool
+server_setup(struct sudo_event_base *base)
+{
+    struct server_address *addr;
+    struct listener *l;
+    int nlisteners = 0;
+    bool ret;
+    debug_decl(server_setup, SUDO_DEBUG_UTIL);
+
+    /* Free old listeners (if any) and register new ones. */
+    while ((l = TAILQ_FIRST(&listeners)) != NULL) {
+	TAILQ_REMOVE(&listeners, l, entries);
+	sudo_ev_free(l->ev);
+	close(l->sock);
+	free(l);
+    }
+    TAILQ_FOREACH(addr, logsrvd_conf_server_listen_address(), entries) {
+	nlisteners += register_listener(addr, base);
+    }
+    ret = nlisteners > 0;
+
+#if defined(HAVE_OPENSSL)
+    if (ret)
+	set_tls_verify_peer();
+#endif
+
+    debug_return_bool(ret);
+}
+
+/*
+ * Reload config and re-initialize listeners.
+ */
+static void
+server_reload(struct sudo_event_base *evbase)
+{
+    debug_decl(server_reload, SUDO_DEBUG_UTIL);
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "reloading server config");
+    if (logsrvd_conf_read(conf_file)) {
+	/* Re-initialize listeners. */
+	if (!server_setup(evbase))
+	    sudo_fatalx("%s", U_("unable to setup listen socket"));
+
+	/* Re-read sudo.conf and re-initialize debugging. */
+	sudo_debug_deregister(logsrvd_debug_instance);
+	logsrvd_debug_instance = SUDO_DEBUG_INSTANCE_INITIALIZER;
+	if (sudo_conf_read(NULL, SUDO_CONF_DEBUG) != -1) {
+	    logsrvd_debug_instance = sudo_debug_register(getprogname(),
+		NULL, NULL, sudo_conf_debug_files(getprogname()), -1);
+	}
+    }
+
+    debug_return;
+}
+
+/*
+ * Dump server information to the debug file.
+ * Includes information about listeners and client connections.
+ */
+static void
+server_dump_stats(void)
+{
+    struct server_address *addr;
+    struct connection_closure *closure;
+    int n;
+    debug_decl(server_dump_stats, SUDO_DEBUG_UTIL);
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "%s", server_id);
+    sudo_debug_printf(SUDO_DEBUG_INFO, "configuration file: %s", conf_file);
+
+    sudo_debug_printf(SUDO_DEBUG_INFO, "listen addresses:");
+    n = 0;
+    TAILQ_FOREACH(addr, logsrvd_conf_server_listen_address(), entries) {
+	union sockaddr_union *sa_un = &addr->sa_un;
+	char ipaddr[INET6_ADDRSTRLEN];
+
+	switch (sa_un->sa.sa_family) {
+	case AF_INET:
+	    inet_ntop(AF_INET, &sa_un->sin.sin_addr, ipaddr, sizeof(ipaddr));
+	    break;
+#ifdef HAVE_STRUCT_IN6_ADDR
+	case AF_INET6:
+	    inet_ntop(AF_INET6, &sa_un->sin6.sin6_addr, ipaddr, sizeof(ipaddr));
+	    break;
+#endif /* HAVE_STRUCT_IN6_ADDR */
+	default:
+	    (void)strlcpy(ipaddr, "[unknown]", sizeof(ipaddr));
+	    break;
+	}
+	sudo_debug_printf(SUDO_DEBUG_INFO, "  %d: %s [%s]", ++n,
+	    addr->sa_str, ipaddr);
+    }
+
+    if (!TAILQ_EMPTY(&connections)) {
+	n = 0;
+	sudo_debug_printf(SUDO_DEBUG_INFO, "client connections:");
+	TAILQ_FOREACH(closure, &connections, entries) {
+	    struct relay_closure *relay_closure = closure->relay_closure;
+
+	    n++;
+	    if (closure->sock == -1) {
+		sudo_debug_printf(SUDO_DEBUG_INFO, "  %2d: journal %s", n,
+		    closure->journal_path ? closure->journal_path : "none");
+		sudo_debug_printf(SUDO_DEBUG_INFO, "  %2d: fd %d", n,
+		    closure->journal ? fileno(closure->journal) : -1);
+	    } else {
+		sudo_debug_printf(SUDO_DEBUG_INFO, "  %2d: addr %s%s", n,
+		    closure->ipaddr, closure->tls ? " (TLS)" : "");
+		sudo_debug_printf(SUDO_DEBUG_INFO, "  %2d: sock %d", n,
+		    closure->sock);
+	    }
+	    if (relay_closure != NULL) {
+		sudo_debug_printf(SUDO_DEBUG_INFO, "      relay: %s (%s)",
+		    relay_closure->relay_name.name,
+		    relay_closure->relay_name.ipaddr);
+		sudo_debug_printf(SUDO_DEBUG_INFO, "      relay sock: %d",
+		    relay_closure->sock);
+	    }
+	    sudo_debug_printf(SUDO_DEBUG_INFO, "      state: %d", closure->state);
+	    if (closure->errstr != NULL) {
+		sudo_debug_printf(SUDO_DEBUG_INFO, "      error: %s",
+		    closure->errstr);
+	    }
+	    sudo_debug_printf(SUDO_DEBUG_INFO, "      log I/O: %s",
+		closure->log_io ? "true" : "false");
+	    sudo_debug_printf(SUDO_DEBUG_INFO, "      store first: %s",
+		closure->store_first ? "true" : "false");
+	    if (sudo_timespecisset(&closure->elapsed_time)) {
+		sudo_debug_printf(SUDO_DEBUG_INFO,
+		    "      elapsed time: [%lld, %ld]",
+		    (long long)closure->elapsed_time.tv_sec,
+		    (long)closure->elapsed_time.tv_nsec);
+	    }
+	}
+	sudo_debug_printf(SUDO_DEBUG_INFO, "%d client connection(s)\n", n);
+    }
+    logsrvd_queue_dump();
+
+    debug_return;
+}
+
+static void
+signal_cb(int signo, int what, void *v)
+{
+    struct sudo_event_base *base = v;
+    debug_decl(signal_cb, SUDO_DEBUG_UTIL);
+
+    switch (signo) {
+	case SIGHUP:
+	    server_reload(base);
+	    break;
+	case SIGINT:
+	case SIGTERM:
+	    /* Shut down active connections. */
+	    server_shutdown(base);
+	    break;
+	case SIGUSR1:
+	    server_dump_stats();
+	    break;
+	default:
+	    sudo_warnx(U_("unexpected signal %d"), signo);
+	    break;
+    }
+
+    debug_return;
+}
+
+static void
+register_signal(int signo, struct sudo_event_base *base)
+{
+    struct sudo_event *ev;
+    debug_decl(register_signal, SUDO_DEBUG_UTIL);
+
+    ev = sudo_ev_alloc(signo, SUDO_EV_SIGNAL, signal_cb, base);
+    if (ev == NULL)
+	sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+    if (sudo_ev_add(base, ev, NULL, false) == -1)
+	sudo_fatal("%s", U_("unable to add event to queue"));
+
+    debug_return;
+}
+
+static void
+logsrvd_cleanup(void)
+{
+    /* TODO: cleanup like on signal */
+    return;
+}
+
+/*
+ * Write the process ID into a file, typically /var/run/sudo/sudo_logsrvd.pid.
+ * If the parent directory doesn't exist, it will be created.
+ */
+static void
+write_pidfile(void)
+{
+    FILE *fp;
+    int dfd, fd;
+    mode_t oldmask;
+    const char *pid_file = logsrvd_conf_pid_file();
+    debug_decl(write_pidfile, SUDO_DEBUG_UTIL);
+
+    if (pid_file == NULL)
+	debug_return;
+
+    /* Default logsrvd umask is more restrictive (077). */
+    oldmask = umask(S_IWGRP|S_IWOTH);
+
+    dfd = sudo_open_parent_dir(pid_file, ROOT_UID, ROOT_GID,
+	S_IRWXU|S_IXGRP|S_IXOTH, false);
+    if (dfd != -1) {
+	const char *base = sudo_basename(pid_file);
+	fd = openat(dfd, base, O_WRONLY|O_CREAT|O_NOFOLLOW, 0644);
+	if (fd == -1 || (fp = fdopen(fd, "w")) == NULL) {
+	    sudo_warn("%s", pid_file);
+	    if (fd != -1)
+		close(fd);
+	} else {
+	    fprintf(fp, "%u\n", (unsigned int)getpid());
+	    fflush(fp);
+	    if (ferror(fp))
+		sudo_warn("%s", pid_file);
+	    fclose(fp);
+	}
+	close(dfd);
+    }
+    umask(oldmask);
+
+    debug_return;
+}
+
+/*
+ * Fork, detach from the terminal and write pid file unless nofork set.
+ */
+static void
+daemonize(bool nofork)
+{
+    int fd;
+    debug_decl(daemonize, SUDO_DEBUG_UTIL);
+
+    if (chdir("/") == -1)
+	sudo_warn("chdir(\"/\")");
+
+    if (!nofork) {
+	switch (sudo_debug_fork()) {
+	case -1:
+	    sudo_fatal("fork");
+	case 0:
+	    /* child */
+	    break;
+	default:
+	    /* parent, exit */
+	    _exit(EXIT_SUCCESS);
+	}
+
+	/* detach from terminal and write pid file. */
+	if (setsid() == -1)
+	    sudo_fatal("setsid");
+	write_pidfile();
+
+	if ((fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
+	    (void) dup2(fd, STDIN_FILENO);
+	    (void) dup2(fd, STDOUT_FILENO);
+	    (void) dup2(fd, STDERR_FILENO);
+	    if (fd > STDERR_FILENO)
+		(void) close(fd);
+	}
+    } else {
+	if ((fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
+	    /* Preserve stdout/stderr in nofork mode (if open). */
+	    (void) dup2(fd, STDIN_FILENO);
+	    if (fcntl(STDOUT_FILENO, F_GETFL) == -1)
+		(void) dup2(fd, STDOUT_FILENO);
+	    if (fcntl(STDERR_FILENO, F_GETFL) == -1)
+		(void) dup2(fd, STDERR_FILENO);
+	    if (fd > STDERR_FILENO)
+		(void) close(fd);
+	}
+    }
+
+    /* Disable logging to stderr after we become a daemon. */
+    logsrvd_warn_stderr(false);
+
+    debug_return;
+}
+
+static void
+usage(bool fatal)
+{
+    fprintf(stderr, "usage: %s [-n] [-f conf_file] [-R percentage]\n",
+	getprogname());
+    if (fatal)
+	exit(EXIT_FAILURE);
+}
+
+static void
+help(void)
+{
+    printf("%s - %s\n\n", getprogname(), _("sudo log server"));
+    usage(false);
+    printf("\n%s\n", _("Options:"));
+    printf("  -f, --file            %s\n",
+	_("path to configuration file"));
+    printf("  -h, --help            %s\n",
+        _("display help message and exit"));
+    printf("  -n, --no-fork         %s\n",
+	_("do not fork, run in the foreground"));
+    printf("  -R, --random-drop     %s\n",
+	_("percent chance connections will drop"));
+    printf("  -V, --version         %s\n",
+	_("display version information and exit"));
+    putchar('\n');
+    exit(EXIT_SUCCESS);
+}
+
+static const char short_opts[] = "f:hnR:V";
+static struct option long_opts[] = {
+    { "file",		required_argument,	NULL,	'f' },
+    { "help",		no_argument,		NULL,	'h' },
+    { "no-fork",	no_argument,		NULL,	'n' },
+    { "random-drop",	required_argument,	NULL,	'R' },
+    { "version",	no_argument,		NULL,	'V' },
+    { NULL,		no_argument,		NULL,	0 },
+};
+
+sudo_dso_public int main(int argc, char *argv[]);
+
+int
+main(int argc, char *argv[])
+{
+    struct sudo_event_base *evbase;
+    bool nofork = false;
+    int ch;
+    debug_decl_vars(main, SUDO_DEBUG_MAIN);
+
+#if defined(SUDO_DEVEL) && defined(__OpenBSD__)
+    {
+	extern char *malloc_options;
+	malloc_options = "S";
+    }
+#endif
+
+    initprogname(argc > 0 ? argv[0] : "sudo_logsrvd");
+    setlocale(LC_ALL, "");
+    bindtextdomain("sudo", LOCALEDIR); /* XXX - add logsrvd domain */
+    textdomain("sudo");
+
+    /* Create files readable/writable only by owner. */
+    umask(S_IRWXG|S_IRWXO);
+
+    /* Register fatal/fatalx callback. */
+    sudo_fatal_callback_register(logsrvd_cleanup);
+
+    /* Read sudo.conf and initialize the debug subsystem. */
+    if (sudo_conf_read(NULL, SUDO_CONF_DEBUG) == -1)
+        exit(EXIT_FAILURE);
+    logsrvd_debug_instance = sudo_debug_register(getprogname(), NULL, NULL,
+        sudo_conf_debug_files(getprogname()), -1);
+
+    if (protobuf_c_version_number() < 1003000)
+	sudo_fatalx("%s", U_("Protobuf-C version 1.3 or higher required"));
+
+    while ((ch = getopt_long(argc, argv, short_opts, long_opts, NULL)) != -1) {
+	switch (ch) {
+	case 'f':
+	    conf_file = optarg;
+	    break;
+	case 'h':
+	    help();
+	    break;
+	case 'n':
+	    nofork = true;
+	    break;
+	case 'R':
+	    /* random connection drop probability as a percentage (debug) */
+	    if (!set_random_drop(optarg))
+                sudo_fatalx(U_("invalid random drop value: %s"), optarg);
+	    break;
+	case 'V':
+	    (void)printf(_("%s version %s\n"), getprogname(),
+		PACKAGE_VERSION);
+	    return 0;
+	default:
+	    usage(true);
+	}
+    }
+
+    /* Read sudo_logsrvd.conf */
+    if (!logsrvd_conf_read(conf_file))
+        exit(EXIT_FAILURE);
+
+    if ((evbase = sudo_ev_base_alloc()) == NULL)
+	sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
+
+    /* Initialize listeners. */
+    if (!server_setup(evbase))
+	sudo_fatalx("%s", U_("unable to setup listen socket"));
+
+    register_signal(SIGHUP, evbase);
+    register_signal(SIGINT, evbase);
+    register_signal(SIGTERM, evbase);
+    register_signal(SIGUSR1, evbase);
+
+    /* Point of no return. */
+    daemonize(nofork);
+    signal(SIGPIPE, SIG_IGN);
+
+    logsrvd_queue_scan(evbase);
+    sudo_ev_dispatch(evbase);
+    if (!nofork && logsrvd_conf_pid_file() != NULL)
+	unlink(logsrvd_conf_pid_file());
+    logsrvd_conf_cleanup();
+
+    debug_return_int(1);
+}