X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=command.c;h=6b9f91de7a9b2acf76dd1e719fa6c88af96310ea;hp=2e733c5c6151b87eff0a9ac1c16b65ab64cbf5ad;hb=8f69a1302a52163c61142531c4a6944510c3ec12;hpb=bc0e339169727c602b3e3939be494fa67b0e5b79

diff --git a/command.c b/command.c
index 2e733c5c..6b9f91de 100644
--- a/command.c
+++ b/command.c
@@ -1,22 +1,24 @@
-/*
- * Copyright (C) 1997-2013 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
 
 /** \file command.c Client authentication and server commands. */
 
+#include <netinet/in.h>
+#include <sys/socket.h>
 #include <regex.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <osl.h>
+#include <arpa/inet.h>
+#include <sys/un.h>
+#include <netdb.h>
+#include <lopsub.h>
 
+#include "server.lsg.h"
 #include "para.h"
 #include "error.h"
 #include "crypt.h"
 #include "sideband.h"
 #include "command.h"
-#include "server.cmdline.h"
 #include "string.h"
 #include "afh.h"
 #include "afs.h"
@@ -29,41 +31,42 @@
 #include "daemon.h"
 #include "fd.h"
 #include "ipc.h"
+#include "server_cmd.lsg.h"
 #include "user_list.h"
-#include "server_command_list.h"
-#include "afs_command_list.h"
 #include "signal.h"
 #include "version.h"
 
-struct server_command afs_cmds[] = {DEFINE_AFS_CMD_ARRAY};
-struct server_command server_cmds[] = {DEFINE_SERVER_CMD_ARRAY};
+#define SERVER_CMD_AUX_INFO(_arg) _arg,
+static const unsigned server_command_perms[] = {LSG_SERVER_CMD_AUX_INFOS};
+#undef SERVER_CMD_AUX_INFO
+#define SERVER_CMD_AUX_INFO(_arg) #_arg,
+static const char * const server_command_perms_txt[] = {LSG_SERVER_CMD_AUX_INFOS};
+#undef SERVER_CMD_AUX_INFO
 
 /** Commands including options must be shorter than this. */
 #define MAX_COMMAND_LEN 32768
 
 extern int mmd_mutex;
 extern struct misc_meta_data *mmd;
-extern struct sender senders[];
 int send_afs_status(struct command_context *cc, int parser_friendly);
+static bool subcmd_should_die;
 
-static void dummy(__a_unused int s)
-{
-}
-
-static void mmd_dup(struct misc_meta_data *new_mmd)
+static void command_handler_sighandler(int s)
 {
-	mutex_lock(mmd_mutex);
-	*new_mmd = *mmd;
-	mutex_unlock(mmd_mutex);
+	if (s != SIGTERM)
+		return;
+	PARA_EMERG_LOG("terminating on signal %d\n", SIGTERM);
+	subcmd_should_die = true;
 }
 
 /*
- * Compute human readable string containing vss status for given integer value.
+ * Compute human readable vss status text.
  *
- * We don't want to use vss_playing() and friends here because we take a
- * snapshot of the mmd struct and use the copy for computing the state of the
- * vss. If the real data were used, we would take the mmd lock for a rather
- * long time or risk to get an inconsistent view.
+ * We can't call vss_playing() and friends here because those functions read
+ * the flags from the primary mmd structure, so calling them from command
+ * handler context would require to take the mmd lock. At the time the function
+ * is called we already took a copy of the mmd structure and want to use the
+ * flags value of the copy for computing the vss status text.
  */
 static char *vss_status_tohuman(unsigned int flags)
 {
@@ -74,21 +77,6 @@ static char *vss_status_tohuman(unsigned int flags)
 	return para_strdup("paused");
 }
 
-/*
- * return human readable permission string. Never returns NULL.
- */
-static char *cmd_perms_itohuman(unsigned int perms)
-{
-	char *msg = para_malloc(5 * sizeof(char));
-
-	msg[0] = perms & AFS_READ? 'a' : '-';
-	msg[1] = perms & AFS_WRITE? 'A' : '-';
-	msg[2] = perms & VSS_READ? 'v' : '-';
-	msg[3] = perms & VSS_WRITE? 'V' : '-';
-	msg[4] = '\0';
-	return msg;
-}
-
 /*
  * Never returns NULL.
  */
@@ -104,98 +92,41 @@ static char *vss_get_status_flags(unsigned int flags)
 	return msg;
 }
 
-static unsigned get_status(struct misc_meta_data *nmmd, int parser_friendly,
+static unsigned get_status(struct misc_meta_data *nmmd, bool parser_friendly,
 		char **result)
 {
-	char mtime[30] = "";
 	char *status, *flags; /* vss status info */
 	/* nobody updates our version of "now" */
-	char *ut = get_server_uptime_str(NULL);
 	long offset = (nmmd->offset + 500) / 1000;
 	struct timeval current_time;
-	struct tm mtime_tm;
 	struct para_buffer b = {.flags = parser_friendly? PBF_SIZE_PREFIX : 0};
 
 	/* report real status */
 	status = vss_status_tohuman(nmmd->vss_status_flags);
 	flags = vss_get_status_flags(nmmd->vss_status_flags);
-	if (nmmd->size) { /* parent currently has an audio file open */
-		localtime_r(&nmmd->mtime, &mtime_tm);
-		strftime(mtime, 29, "%b %d %Y", &mtime_tm);
-	}
 	clock_get_realtime(&current_time);
 	/*
 	 * The calls to WRITE_STATUS_ITEM() below never fail because
-	 * b->max_size is zero (unlimited), see para_printf(). However, clang
-	 * is not smart enough to prove this and complains nevertheless.
+	 * b->max_size is zero (unlimited), see \ref para_printf(). However,
+	 * clang is not smart enough to prove this and complains nevertheless.
 	 * Casting the return value to void silences clang.
 	 */
-	(void)WRITE_STATUS_ITEM(&b, SI_FILE_SIZE, "%zu\n", nmmd->size / 1024);
-	(void)WRITE_STATUS_ITEM(&b, SI_MTIME, "%s\n", mtime);
-	(void)WRITE_STATUS_ITEM(&b, SI_STATUS, "%s\n", status);
-	(void)WRITE_STATUS_ITEM(&b, SI_STATUS_FLAGS, "%s\n", flags);
-	(void)WRITE_STATUS_ITEM(&b, SI_OFFSET, "%li\n", offset);
-	(void)WRITE_STATUS_ITEM(&b, SI_AFS_MODE, "%s\n", mmd->afs_mode_string);
-	(void)WRITE_STATUS_ITEM(&b, SI_STREAM_START, "%lu.%lu\n",
+	(void)WRITE_STATUS_ITEM(&b, SI_status, "%s\n", status);
+	(void)WRITE_STATUS_ITEM(&b, SI_status_flags, "%s\n", flags);
+	(void)WRITE_STATUS_ITEM(&b, SI_offset, "%li\n", offset);
+	(void)WRITE_STATUS_ITEM(&b, SI_afs_mode, "%s\n", mmd->afs_mode_string);
+	(void)WRITE_STATUS_ITEM(&b, SI_stream_start, "%lu.%lu\n",
 		(long unsigned)nmmd->stream_start.tv_sec,
 		(long unsigned)nmmd->stream_start.tv_usec);
-	(void)WRITE_STATUS_ITEM(&b, SI_CURRENT_TIME, "%lu.%lu\n",
+	(void)WRITE_STATUS_ITEM(&b, SI_current_time, "%lu.%lu\n",
 		(long unsigned)current_time.tv_sec,
 		(long unsigned)current_time.tv_usec);
 	free(flags);
 	free(status);
-	free(ut);
 	*result = b.buf;
 	return b.offset;
 }
 
-static int check_sender_args(int argc, char * const * argv, struct sender_command_data *scd)
-{
-	int i;
-	/* this has to match sender.h */
-	const char *subcmds[] = {"add", "delete", "allow", "deny", "on", "off", NULL};
-
-	scd->sender_num = -1;
-	if (argc < 2)
-		return -E_COMMAND_SYNTAX;
-	for (i = 0; senders[i].name; i++)
-		if (!strcmp(senders[i].name, argv[1]))
-			break;
-	PARA_DEBUG_LOG("%d:%s\n", argc, argv[1]);
-	if (!senders[i].name)
-		return -E_COMMAND_SYNTAX;
-	scd->sender_num = i;
-	for (i = 0; subcmds[i]; i++)
-		if (!strcmp(subcmds[i], argv[2]))
-			break;
-	if (!subcmds[i])
-		return -E_COMMAND_SYNTAX;
-	scd->cmd_num = i;
-	if (!senders[scd->sender_num].client_cmds[scd->cmd_num])
-		return -E_SENDER_CMD;
-	switch (scd->cmd_num) {
-	case SENDER_ON:
-	case SENDER_OFF:
-		if (argc != 3)
-			return -E_COMMAND_SYNTAX;
-		break;
-	case SENDER_DENY:
-	case SENDER_ALLOW:
-		if (argc != 4 || parse_cidr(argv[3], scd->host,
-				sizeof(scd->host), &scd->netmask) == NULL)
-			return -E_COMMAND_SYNTAX;
-		break;
-	case SENDER_ADD:
-	case SENDER_DELETE:
-		if (argc != 4)
-			return -E_COMMAND_SYNTAX;
-		return parse_fec_url(argv[3], scd);
-	default:
-		return -E_COMMAND_SYNTAX;
-	}
-	return 1;
-}
-
 /**
  * Send a sideband packet through a blocking file descriptor.
  *
@@ -207,7 +138,7 @@ static int check_sender_args(int argc, char * const * argv, struct sender_comman
  *
  * The nonblock flag must be disabled for the file descriptor given by \a scc.
  *
- * Stream cipher encryption is automatically activated if neccessary via the
+ * Stream cipher encryption is automatically activated if necessary via the
  * sideband transformation, depending on the value of \a band.
  *
  * \return Standard.
@@ -220,8 +151,8 @@ int send_sb(struct stream_cipher_context *scc, void *buf, size_t numbytes,
 	int ret;
 	struct sb_context *sbc;
 	struct iovec iov[2];
-	struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
 	sb_transformation trafo = band < SBD_PROCEED? NULL : sc_trafo;
+	struct sb_buffer sbb = SBB_INIT(band, buf, numbytes);
 
 	sbc = sb_new_send(&sbb, dont_free, trafo, scc->send);
 	do {
@@ -268,10 +199,82 @@ __printf_3_4 int send_sb_va(struct stream_cipher_context *scc, int band,
  */
 int send_strerror(struct command_context *cc, int err)
 {
-	return cc->use_sideband?
-		send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err))
-	:
-		sc_send_va_buffer(&cc->scc, "%s\n", para_strerror(err));
+	return send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", para_strerror(err));
+}
+
+/**
+ * Send an error context to a client,
+ *
+ * \param cc Client info.
+ * \param errctx The error context string.
+ *
+ * \return The return value of the underlying call to send_sb_va().
+ *
+ * This function frees the error context string after it was sent.
+ */
+int send_errctx(struct command_context *cc, char *errctx)
+{
+	int ret;
+
+	if (!errctx)
+		return 0;
+	ret = send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s\n", errctx);
+	free(errctx);
+	return ret;
+}
+
+static int check_sender_args(struct command_context *cc,
+		struct lls_parse_result *lpr, struct sender_command_data *scd)
+{
+	int i, ret;
+	const char * const subcmds[] = {SENDER_SUBCOMMANDS};
+	const char *arg;
+	char *errctx;
+	unsigned num_inputs = lls_num_inputs(lpr);
+
+	scd->sender_num = -1;
+	ret = lls(lls_check_arg_count(lpr, 2, INT_MAX, &errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
+	}
+	arg = lls_input(0, lpr);
+	FOR_EACH_SENDER(i)
+		if (strcmp(senders[i]->name, arg) == 0)
+			break;
+	if (!senders[i])
+		return -E_COMMAND_SYNTAX;
+	scd->sender_num = i;
+	arg = lls_input(1, lpr);
+	for (i = 0; i < NUM_SENDER_CMDS; i++)
+		if (!strcmp(subcmds[i], arg))
+			break;
+	if (i == NUM_SENDER_CMDS)
+		return -E_COMMAND_SYNTAX;
+	scd->cmd_num = i;
+	if (!senders[scd->sender_num]->client_cmds[scd->cmd_num])
+		return -E_SENDER_CMD;
+	switch (scd->cmd_num) {
+	case SENDER_on:
+	case SENDER_off:
+		if (num_inputs != 2)
+			return -E_COMMAND_SYNTAX;
+		break;
+	case SENDER_deny:
+	case SENDER_allow:
+		if (num_inputs != 3 || parse_cidr(lls_input(2, lpr), scd->host,
+				sizeof(scd->host), &scd->netmask) == NULL)
+			return -E_COMMAND_SYNTAX;
+		break;
+	case SENDER_add:
+	case SENDER_delete:
+		if (num_inputs != 3)
+			return -E_COMMAND_SYNTAX;
+		return parse_fec_url(lls_input(2, lpr), scd);
+	default:
+		return -E_COMMAND_SYNTAX;
+	}
+	return 1;
 }
 
 /**
@@ -324,44 +327,39 @@ fail:
 	return ret;
 }
 
-static int com_sender(struct command_context *cc)
+static int com_sender(struct command_context *cc, struct lls_parse_result *lpr)
 {
 	int i, ret = 0;
 	char *msg = NULL;
 	struct sender_command_data scd;
 
-	if (cc->argc < 2) {
-		for (i = 0; senders[i].name; i++) {
+	if (lls_num_inputs(lpr) == 0) {
+		FOR_EACH_SENDER(i) {
 			char *tmp;
 			ret = xasprintf(&tmp, "%s%s\n", msg? msg : "",
-				senders[i].name);
+				senders[i]->name);
 			free(msg);
 			msg = tmp;
 		}
-		if (cc->use_sideband)
-			return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
-		ret = sc_send_buffer(&cc->scc, msg);
-		free(msg);
-		return ret;
+		return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
 	}
-	ret = check_sender_args(cc->argc, cc->argv, &scd);
+	ret = check_sender_args(cc, lpr, &scd);
 	if (ret < 0) {
 		if (scd.sender_num < 0)
 			return ret;
-		msg = senders[scd.sender_num].help();
-		if (cc->use_sideband)
-			return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT,
-				false);
-		ret = sc_send_buffer(&cc->scc, msg);
-		free(msg);
-		return ret;
+		if (strcmp(lls_input(1, lpr), "status") == 0)
+			msg = senders[scd.sender_num]->status();
+		else
+			msg = senders[scd.sender_num]->help();
+		return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
 	}
 
 	switch (scd.cmd_num) {
-	case SENDER_ADD:
-	case SENDER_DELETE:
-		assert(senders[scd.sender_num].resolve_target);
-		ret = senders[scd.sender_num].resolve_target(cc->argv[3], &scd);
+	case SENDER_add:
+	case SENDER_delete:
+		assert(senders[scd.sender_num]->resolve_target);
+		ret = senders[scd.sender_num]->resolve_target(lls_input(2, lpr),
+			&scd);
 		if (ret < 0)
 			return ret;
 	}
@@ -369,115 +367,101 @@ static int com_sender(struct command_context *cc)
 	for (i = 0; i < 10; i++) {
 		mutex_lock(mmd_mutex);
 		if (mmd->sender_cmd_data.cmd_num >= 0) {
+			/* another sender command is active, retry in 100ms */
+			struct timespec ts = {.tv_nsec = 100 * 1000 * 1000};
 			mutex_unlock(mmd_mutex);
-			usleep(100 * 1000);
+			nanosleep(&ts, NULL);
 			continue;
 		}
-		memcpy(&mmd->sender_cmd_data, &scd, sizeof(scd));
+		mmd->sender_cmd_data = scd;
 		mutex_unlock(mmd_mutex);
 		break;
 	}
 	return (i < 10)? 1 : -E_LOCK;
 }
+EXPORT_SERVER_CMD_HANDLER(sender);
 
-/* server info */
-static int com_si(struct command_context *cc)
+static int com_si(struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	int i, ret;
-	char *msg, *ut, *sender_info = NULL;
+	char *msg, *ut;
+	int ret;
 
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
+	ut = daemon_get_uptime_str(now);
 	mutex_lock(mmd_mutex);
-	for (i = 0; senders[i].name; i++) {
-		char *info = senders[i].info();
-		sender_info = para_strcat(sender_info, info);
-		free(info);
-	}
-	ut = get_server_uptime_str(now);
 	ret = xasprintf(&msg,
-		"version: %s\n"
 		"up: %s\nplayed: %u\n"
 		"server_pid: %d\n"
 		"afs_pid: %d\n"
 		"connections (active/accepted/total): %u/%u/%u\n"
 		"current loglevel: %s\n"
-		"supported audio formats: %s\n"
-		"%s",
-		version_git(),
+		"supported audio formats: %s\n",
 		ut, mmd->num_played,
 		(int)getppid(),
-		(int)mmd->afs_pid,
+		(int)afs_pid,
 		mmd->active_connections,
 		mmd->num_commands,
 		mmd->num_connects,
-		conf.loglevel_arg,
-		AUDIO_FORMAT_HANDLERS,
-		sender_info
+		ENUM_STRING_VAL(LOGLEVEL),
+		AUDIO_FORMAT_HANDLERS
 	);
 	mutex_unlock(mmd_mutex);
 	free(ut);
-	free(sender_info);
-	if (cc->use_sideband)
-		return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
-	ret = sc_send_bin_buffer(&cc->scc, msg, ret);
-	free(msg);
-	return ret;
+	return send_sb(&cc->scc, msg, ret, SBD_OUTPUT, false);
 }
+EXPORT_SERVER_CMD_HANDLER(si);
 
-/* version */
-static int com_version(struct command_context *cc)
+static int com_version(struct command_context *cc, struct lls_parse_result *lpr)
 {
 	char *msg;
 	size_t len;
 
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
-	len = xasprintf(&msg, "%s", version_text("server"));
-	if (cc->use_sideband)
-		return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
-	return sc_send_bin_buffer(&cc->scc, msg, len);
+	if (SERVER_CMD_OPT_GIVEN(VERSION, VERBOSE, lpr))
+		len = xasprintf(&msg, "%s", version_text("server"));
+	else
+		len = xasprintf(&msg, "%s\n", version_single_line("server"));
+	return send_sb(&cc->scc, msg, len, SBD_OUTPUT, false);
 }
+EXPORT_SERVER_CMD_HANDLER(version);
 
 /** These status items are cleared if no audio file is currently open. */
 #define EMPTY_STATUS_ITEMS \
-	ITEM(PATH) \
-	ITEM(DIRECTORY) \
-	ITEM(BASENAME) \
-	ITEM(SCORE) \
-	ITEM(ATTRIBUTES_BITMAP) \
-	ITEM(ATTRIBUTES_TXT) \
-	ITEM(HASH) \
-	ITEM(IMAGE_ID) \
-	ITEM(IMAGE_NAME) \
-	ITEM(LYRICS_ID) \
-	ITEM(LYRICS_NAME) \
-	ITEM(BITRATE) \
-	ITEM(FORMAT) \
-	ITEM(FREQUENCY) \
-	ITEM(CHANNELS) \
-	ITEM(DURATION) \
-	ITEM(SECONDS_TOTAL) \
-	ITEM(NUM_PLAYED) \
-	ITEM(LAST_PLAYED) \
-	ITEM(TECHINFO) \
-	ITEM(ARTIST) \
-	ITEM(TITLE) \
-	ITEM(YEAR) \
-	ITEM(ALBUM) \
-	ITEM(COMMENT) \
-	ITEM(MTIME) \
-	ITEM(FILE_SIZE) \
-	ITEM(CHUNK_TIME) \
-	ITEM(NUM_CHUNKS) \
-	ITEM(AMPLIFICATION) \
+	ITEM(path) \
+	ITEM(directory) \
+	ITEM(basename) \
+	ITEM(score) \
+	ITEM(attributes_bitmap) \
+	ITEM(attributes_txt) \
+	ITEM(hash) \
+	ITEM(image_id) \
+	ITEM(image_name) \
+	ITEM(lyrics_id) \
+	ITEM(lyrics_name) \
+	ITEM(bitrate) \
+	ITEM(format) \
+	ITEM(frequency) \
+	ITEM(channels) \
+	ITEM(duration) \
+	ITEM(seconds_total) \
+	ITEM(num_played) \
+	ITEM(last_played) \
+	ITEM(techinfo) \
+	ITEM(artist) \
+	ITEM(title) \
+	ITEM(year) \
+	ITEM(album) \
+	ITEM(comment) \
+	ITEM(mtime) \
+	ITEM(file_size) \
+	ITEM(chunk_time) \
+	ITEM(num_chunks) \
+	ITEM(amplification) \
 
-/**
- * Write a list of audio-file related status items with empty values.
- *
- * This is used by vss when currently no audio file is open.
+/*
+ * Create a set of audio-file related status items with empty values. These are
+ * written to stat clients when no audio file is open.
  */
-static unsigned empty_status_items(int parser_friendly, char **result)
+static unsigned empty_status_items(bool parser_friendly, char **result)
 {
 	char *esi;
 	unsigned len;
@@ -487,7 +471,7 @@ static unsigned empty_status_items(int parser_friendly, char **result)
 			#define ITEM(x) "0004 %02x:\n"
 			EMPTY_STATUS_ITEMS
 			#undef ITEM
-			#define ITEM(x) , SI_ ## x
+			#define ITEM(x) , (unsigned) SI_ ## x
 			EMPTY_STATUS_ITEMS
 			#undef ITEM
 		);
@@ -505,60 +489,44 @@ static unsigned empty_status_items(int parser_friendly, char **result)
 }
 #undef EMPTY_STATUS_ITEMS
 
-/* stat */
-static int com_stat(struct command_context *cc)
+static int com_stat(struct command_context *cc, struct lls_parse_result *lpr)
 {
-	int i, ret;
+	int ret;
 	struct misc_meta_data tmp, *nmmd = &tmp;
 	char *s;
-	int32_t num = 0;
-	int parser_friendly = 0;
-
-	para_sigaction(SIGUSR1, dummy);
-
-	for (i = 1; i < cc->argc; i++) {
-		const char *arg = cc->argv[i];
-		if (arg[0] != '-')
-			break;
-		if (!strcmp(arg, "--")) {
-			i++;
-			break;
-		}
-		if (!strncmp(arg, "-n=", 3)) {
-			ret = para_atoi32(arg + 3, &num);
-			if (ret < 0)
-				return ret;
-			continue;
-		}
-		if (!strcmp(arg, "-p")) {
-			parser_friendly = 1;
-			continue;
-		}
-		return -E_COMMAND_SYNTAX;
-	}
-	if (i != cc->argc)
-		return -E_COMMAND_SYNTAX;
+	bool parser_friendly = SERVER_CMD_OPT_GIVEN(STAT, PARSER_FRIENDLY,
+		lpr) > 0;
+	uint32_t num = SERVER_CMD_UINT32_VAL(STAT, NUM, lpr);
+	const struct timespec ts = {.tv_sec = 50, .tv_nsec = 0};
+
+	para_sigaction(SIGINT, SIG_IGN);
+	para_sigaction(SIGUSR1, command_handler_sighandler);
+	para_sigaction(SIGTERM, command_handler_sighandler);
+	/*
+	 * Simply checking subcmd_should_die is racy because a signal may
+	 * arrive after the check but before the subsequent call to sleep(3).
+	 * If this happens, sleep(3) would not be interrupted by the signal.
+	 * To avoid this we block SIGTERM here and allow it to arrive only
+	 * while we sleep.
+	 */
+	para_block_signal(SIGTERM);
 	for (;;) {
-		mmd_dup(nmmd);
+		sigset_t set;
+		/*
+		 * Copy the mmd structure to minimize the time we hold the mmd
+		 * lock.
+		 */
+		mutex_lock(mmd_mutex);
+		*nmmd = *mmd;
+		mutex_unlock(mmd_mutex);
 		ret = get_status(nmmd, parser_friendly, &s);
-		if (cc->use_sideband)
-			ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
-		else {
-			ret = sc_send_bin_buffer(&cc->scc, s, ret);
-			free(s);
-		}
+		ret = send_sb(&cc->scc, s, ret, SBD_OUTPUT, false);
 		if (ret < 0)
 			goto out;
 		if (nmmd->vss_status_flags & VSS_NEXT) {
 			char *esi;
 			ret = empty_status_items(parser_friendly, &esi);
-			if (cc->use_sideband)
-				ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT,
-					false);
-			else {
-				ret = sc_send_bin_buffer(&cc->scc, esi, ret);
-				free(esi);
-			}
+			ret = send_sb(&cc->scc, esi, ret, SBD_OUTPUT, false);
 			if (ret < 0)
 				goto out;
 		} else
@@ -566,7 +534,15 @@ static int com_stat(struct command_context *cc)
 		ret = 1;
 		if (num > 0 && !--num)
 			goto out;
-		sleep(50);
+		sigemptyset(&set); /* empty set means: unblock all signals */
+		/*
+		 * pselect(2) allows to atomically unblock signals, then go to
+		 * sleep. Calling sigprocmask(2) followed by sleep(3) would
+		 * open a race window similar to the one described above.
+		 */
+		pselect(1, NULL, NULL, NULL, &ts, &set);
+		if (subcmd_should_die)
+			goto out;
 		ret = -E_SERVER_CRASH;
 		if (getppid() == 1)
 			goto out;
@@ -574,122 +550,98 @@ static int com_stat(struct command_context *cc)
 out:
 	return ret;
 }
+EXPORT_SERVER_CMD_HANDLER(stat);
 
-static int send_list_of_commands(struct command_context *cc, struct server_command *cmd,
-		const char *handler)
+/* fixed-length, human readable permission string */
+const char *server_cmd_perms_str(unsigned int perms)
 {
-	int ret;
-	char *msg = NULL;
+	static char result[5];
 
-	for (; cmd->name; cmd++) {
-		char *tmp, *perms = cmd_perms_itohuman(cmd->perms);
-		tmp = make_message("%s\t%s\t%s\t%s\n", cmd->name, handler,
-			perms, cmd->description);
-		free(perms);
-		msg = para_strcat(msg, tmp);
-		free(tmp);
-	}
-	if (cc->use_sideband)
-		return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
-	ret = sc_send_buffer(&cc->scc, msg);
-	free(msg);
-	return ret;
+	result[0] = perms & AFS_READ? 'a' : '-';
+	result[1] = perms & AFS_WRITE? 'A' : '-';
+	result[2] = perms & VSS_READ? 'v' : '-';
+	result[3] = perms & VSS_WRITE? 'V' : '-';
+	result[4] = '\0';
+	return result;
 }
 
-/* returns string that must be freed by the caller */
-static struct server_command *get_cmd_ptr(const char *name, char **handler)
+static int send_list_of_commands(struct command_context *cc)
 {
-	struct server_command *cmd;
+	int i;
+	const struct lls_command *cmd;
+	char *msg = para_strdup("");
 
-	for (cmd = server_cmds; cmd->name; cmd++)
-		if (!strcmp(cmd->name, name)) {
-			if (handler)
-				*handler = para_strdup("server"); /* server commands */
-			return cmd;
-		}
-	/* not found, look for commands supported by afs */
-	for (cmd = afs_cmds; cmd->name; cmd++)
-		if (!strcmp(cmd->name, name)) {
-			if (handler)
-				*handler = para_strdup("afs");
-			return cmd;
-		}
-	return NULL;
+	for (i = 1; (cmd = lls_cmd(i, server_cmd_suite)); i++) {
+		const char *perms = server_cmd_perms_str(server_command_perms[i]);
+		char *tmp = make_message("%s%s\t%s\t%s\n", msg,
+			lls_command_name(cmd), perms, lls_purpose(cmd));
+		free(msg);
+		msg = tmp;
+	}
+	return send_sb(&cc->scc, msg, strlen(msg), SBD_OUTPUT, false);
 }
 
-/* help */
-static int com_help(struct command_context *cc)
+static int com_help(struct command_context *cc, struct lls_parse_result *lpr)
 {
-	struct server_command *cmd;
-	char *perms, *handler, *buf;
+	const char *perms;
+	char *long_help, *buf, *errctx;
 	int ret;
+	const struct lls_command *cmd;
 
-	if (cc->argc < 2) {
-		/* no argument given, print list of commands */
-		if ((ret = send_list_of_commands(cc, server_cmds, "server")) < 0)
-			return ret;
-		return send_list_of_commands(cc, afs_cmds, "afs");
+	ret = lls(lls_check_arg_count(lpr, 0, 1, &errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
 	}
+	if (lls_num_inputs(lpr) == 0)
+		return send_list_of_commands(cc);
 	/* argument given for help */
-	cmd = get_cmd_ptr(cc->argv[1], &handler);
-	if (!cmd)
-		return -E_BAD_CMD;
-	perms = cmd_perms_itohuman(cmd->perms);
-	ret = xasprintf(&buf, "%s - %s\n\n"
-		"handler: %s\n"
-		"permissions: %s\n"
-		"usage: %s\n\n"
-		"%s\n",
-		cc->argv[1],
-		cmd->description,
-		handler,
-		perms,
-		cmd->usage,
-		cmd->help
-	);
-	free(perms);
-	free(handler);
-	if (cc->use_sideband)
-		return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
-	ret = sc_send_buffer(&cc->scc, buf);
-	free(buf);
-	return ret;
+	ret = lls(lls_lookup_subcmd(lls_input(0, lpr), server_cmd_suite,
+		&errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
+	}
+	cmd = lls_cmd(ret, server_cmd_suite);
+	perms = server_command_perms_txt[ret];
+	long_help = lls_long_help(cmd);
+	assert(long_help);
+	ret = xasprintf(&buf, "%spermissions: %s\n", long_help, perms);
+	free(long_help);
+	return send_sb(&cc->scc, buf, ret, SBD_OUTPUT, false);
 }
+EXPORT_SERVER_CMD_HANDLER(help);
 
-/* hup */
-static int com_hup(struct command_context *cc)
+static int com_hup(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	kill(getppid(), SIGHUP);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(hup);
 
-/* term */
-static int com_term(struct command_context *cc)
+static int com_term(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	kill(getppid(), SIGTERM);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(term);
 
-static int com_play(struct command_context *cc)
+static int com_play(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	mutex_lock(mmd_mutex);
 	mmd->new_vss_status_flags |= VSS_PLAYING;
 	mmd->new_vss_status_flags &= ~VSS_NOMORE;
 	mutex_unlock(mmd_mutex);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(play);
 
-/* stop */
-static int com_stop(struct command_context *cc)
+static int com_stop(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	mutex_lock(mmd_mutex);
 	mmd->new_vss_status_flags &= ~VSS_PLAYING;
 	mmd->new_vss_status_flags &= ~VSS_REPOS;
@@ -697,12 +649,11 @@ static int com_stop(struct command_context *cc)
 	mutex_unlock(mmd_mutex);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(stop);
 
-/* pause */
-static int com_pause(struct command_context *cc)
+static int com_pause(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	mutex_lock(mmd_mutex);
 	if (!vss_paused() && !vss_stopped()) {
 		mmd->events++;
@@ -712,42 +663,44 @@ static int com_pause(struct command_context *cc)
 	mutex_unlock(mmd_mutex);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(pause);
 
-/* next */
-static int com_next(struct command_context *cc)
+static int com_next(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	mutex_lock(mmd_mutex);
 	mmd->events++;
 	mmd->new_vss_status_flags |= VSS_NEXT;
 	mutex_unlock(mmd_mutex);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(next);
 
-/* nomore */
-static int com_nomore(struct command_context *cc)
+static int com_nomore(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	if (cc->argc != 1)
-		return -E_COMMAND_SYNTAX;
 	mutex_lock(mmd_mutex);
 	if (vss_playing() || vss_paused())
 		mmd->new_vss_status_flags |= VSS_NOMORE;
 	mutex_unlock(mmd_mutex);
 	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(nomore);
 
-/* ff */
-static int com_ff(struct command_context *cc)
+static int com_ff(__a_unused struct command_context *cc,
+		struct lls_parse_result *lpr)
 {
 	long promille;
 	int ret, backwards = 0;
 	unsigned i;
-	char c;
+	char c, *errctx;
 
-	if (cc->argc != 2)
-		return -E_COMMAND_SYNTAX;
-	if (!(ret = sscanf(cc->argv[1], "%u%c", &i, &c)))
+	ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
+	}
+	if (!(ret = sscanf(lls_input(0, lpr), "%u%c", &i, &c)))
 		return -E_COMMAND_SYNTAX;
 	if (ret > 1 && c == '-')
 		backwards = 1; /* jmp backwards */
@@ -762,7 +715,7 @@ static int com_ff(struct command_context *cc)
 		promille += 1000 * i / mmd->afd.afhi.seconds_total;
 	if (promille < 0)
 		promille = 0;
-	if (promille >  1000) {
+	if (promille > 1000) {
 		mmd->new_vss_status_flags |= VSS_NEXT;
 		goto out;
 	}
@@ -775,17 +728,22 @@ out:
 	mutex_unlock(mmd_mutex);
 	return ret;
 }
+EXPORT_SERVER_CMD_HANDLER(ff);
 
-/* jmp */
-static int com_jmp(struct command_context *cc)
+static int com_jmp(__a_unused struct command_context *cc,
+		struct lls_parse_result *lpr)
 {
 	long unsigned int i;
 	int ret;
+	char *errctx;
 
-	if (cc->argc != 2)
-		return -E_COMMAND_SYNTAX;
-	if (sscanf(cc->argv[1], "%lu", &i) <= 0)
-		return -E_COMMAND_SYNTAX;
+	ret = lls(lls_check_arg_count(lpr, 1, 1, &errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
+	}
+	if (sscanf(lls_input(0, lpr), "%lu", &i) <= 0)
+		return -ERRNO_TO_PARA_ERROR(EINVAL);
 	mutex_lock(mmd_mutex);
 	ret = -E_NO_AUDIO_FILE;
 	if (!mmd->afd.afhi.chunks_total)
@@ -793,8 +751,8 @@ static int com_jmp(struct command_context *cc)
 	if (i > 100)
 		i = 100;
 	PARA_INFO_LOG("jumping to %lu%%\n", i);
-	mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50)/ 100;
-	PARA_INFO_LOG("sent: %lu,  offset before jmp: %lu\n",
+	mmd->repos_request = (mmd->afd.afhi.chunks_total * i + 50) / 100;
+	PARA_INFO_LOG("sent: %lu, offset before jmp: %li\n",
 		mmd->chunks_sent, mmd->offset);
 	mmd->new_vss_status_flags |= VSS_REPOS;
 	mmd->new_vss_status_flags &= ~VSS_NEXT;
@@ -804,68 +762,15 @@ out:
 	mutex_unlock(mmd_mutex);
 	return ret;
 }
+EXPORT_SERVER_CMD_HANDLER(jmp);
 
-/*
- * check if perms are sufficient to exec a command having perms cmd_perms.
- * Returns 0 if perms are sufficient, -E_PERM otherwise.
- */
-static int check_perms(unsigned int perms, struct server_command *cmd_ptr)
-{
-	PARA_DEBUG_LOG("checking permissions\n");
-	return (cmd_ptr->perms & perms) < cmd_ptr->perms ? -E_PERM : 0;
-}
-
-/*
- * Parse first string from *cmd and lookup in table of valid commands.
- * On error, NULL is returned.
- */
-static struct server_command *parse_cmd(const char *cmdstr)
-{
-	char buf[255];
-	int n = 0;
-
-	sscanf(cmdstr, "%200s%n", buf, &n);
-	if (!n)
-		return NULL;
-	buf[n] = '\0';
-	return get_cmd_ptr(buf, NULL);
-}
-
-static int read_command(struct stream_cipher_context *scc, char **result)
+/* deprecated, does nothing */
+static int com_tasks(__a_unused struct command_context *cc,
+		__a_unused struct lls_parse_result *lpr)
 {
-	int ret;
-	char buf[4096];
-	char *command = NULL;
-
-	for (;;) {
-		size_t numbytes;
-		char *p;
-
-		ret = sc_recv_buffer(scc, buf, sizeof(buf));
-		if (ret < 0)
-			goto out;
-		if (!ret)
-			break;
-		numbytes = ret;
-		ret = -E_COMMAND_SYNTAX;
-		if (command && numbytes + strlen(command) > MAX_COMMAND_LEN) /* DOS */
-			goto out;
-		command = para_strcat(command, buf);
-		p = strstr(command, EOC_MSG);
-		if (p) {
-			*p = '\0';
-			break;
-		}
-	}
-	ret = command? 1 : -E_COMMAND_SYNTAX;
-out:
-	if (ret < 0)
-		free(command);
-	else
-		*result = command;
-	return ret;
-
+	return 1;
 }
+EXPORT_SERVER_CMD_HANDLER(tasks);
 
 static void reset_signals(void)
 {
@@ -875,15 +780,19 @@ static void reset_signals(void)
 	para_sigaction(SIGHUP, SIG_DFL);
 }
 
-static int parse_auth_request(char *buf, int len, struct user **u,
-		bool *use_sideband)
+struct connection_features {
+	int dummy; /* none at the moment */
+};
+
+static int parse_auth_request(char *buf, int len, const struct user **u,
+		struct connection_features *cf)
 {
 	int ret;
 	char *p, *username, **features = NULL;
 	size_t auth_rq_len = strlen(AUTH_REQUEST_MSG);
 
 	*u = NULL;
-	*use_sideband = false;
+	memset(cf, 0, sizeof(*cf));
 	if (len < auth_rq_len + 2)
 		return -E_AUTH_REQUEST;
 	if (strncmp(buf, AUTH_REQUEST_MSG, auth_rq_len) != 0)
@@ -899,16 +808,17 @@ static int parse_auth_request(char *buf, int len, struct user **u,
 		create_argv(p, ",", &features);
 		for (i = 0; features[i]; i++) {
 			if (strcmp(features[i], "sideband") == 0)
-				*use_sideband = true;
+				continue;
+			if (strcmp(features[i], "aes_ctr128") == 0)
+				continue;
 			else {
 				ret = -E_BAD_FEATURE;
 				goto out;
 			}
 		}
 	}
-	PARA_DEBUG_LOG("received auth request for user %s (sideband = %s)\n",
-		username, *use_sideband? "true" : "false");
-	*u = lookup_user(username);
+	PARA_DEBUG_LOG("received auth request for user %s\n", username);
+	*u = user_list_lookup(username);
 	ret = 1;
 out:
 	free_argv(features);
@@ -917,35 +827,54 @@ out:
 
 #define HANDSHAKE_BUFSIZE 4096
 
-static int parse_sb_command(struct command_context *cc, struct iovec *iov)
+static int run_command(struct command_context *cc, struct iovec *iov)
 {
-	int ret, i;
-	char *p, *end;
+	int ret, i, argc;
+	char *p, *end, **argv;
+	const struct lls_command *lcmd = NULL;
+	unsigned perms;
+	struct lls_parse_result *lpr;
+	char *errctx;
 
-	ret = -E_BAD_CMD;
 	if (iov->iov_base == NULL || iov->iov_len == 0)
-		goto out;
+		return -ERRNO_TO_PARA_ERROR(EINVAL);
 	p = iov->iov_base;
 	p[iov->iov_len - 1] = '\0'; /* just to be sure */
-	cc->cmd = get_cmd_ptr(p, NULL);
-	if (!cc->cmd)
-		goto out;
-	ret = check_perms(cc->u->perms, cc->cmd);
-	if (ret < 0)
-		goto out;
+
+	ret = lls(lls_lookup_subcmd(p, server_cmd_suite, &errctx));
+	if (ret < 0) {
+		send_errctx(cc, errctx);
+		return ret;
+	}
+	perms = server_command_perms[ret];
+	if ((perms & cc->u->perms) != perms)
+		return -E_PERM;
+	lcmd = lls_cmd(ret, server_cmd_suite);
 	end = iov->iov_base + iov->iov_len;
-	for (i = 0, p = iov->iov_base; p < end; i++)
+	for (i = 0; p < end; i++)
 		p += strlen(p) + 1;
-	cc->argc = i;
-	cc->argv = para_malloc((cc->argc + 1) * sizeof(char *));
+	argc = i;
+	argv = para_malloc((argc + 1) * sizeof(char *));
 	for (i = 0, p = iov->iov_base; p < end; i++) {
-		cc->argv[i] = para_strdup(p);
+		argv[i] = para_strdup(p);
 		p += strlen(p) + 1;
 	}
-	cc->argv[cc->argc] = NULL;
-	ret = cc->argc;
-out:
-	free(iov->iov_base);
+	argv[argc] = NULL;
+	PARA_NOTICE_LOG("calling com_%s() for user %s\n",
+		lls_command_name(lcmd), cc->u->name);
+	ret = lls(lls_parse(argc, argv, lcmd, &lpr, &errctx));
+	if (ret >= 0) {
+		const struct server_cmd_user_data *ud = lls_user_data(lcmd);
+		ret = ud->handler(cc, lpr);
+		lls_free_parse_result(lpr, lcmd);
+	} else
+		send_errctx(cc, errctx);
+	free_argv(argv);
+	mutex_lock(mmd_mutex);
+	mmd->num_commands++;
+	if (ret >= 0 && (perms & AFS_WRITE))
+		mmd->events++;
+	mutex_unlock(mmd_mutex);
 	return ret;
 }
 
@@ -953,37 +882,38 @@ out:
  * Perform user authentication and execute a command.
  *
  * \param fd The file descriptor to send output to.
- * \param peername Identifies the connecting peer.
  *
- * Whenever para_server accepts an incoming tcp connection on
- * the port it listens on, it forks and the resulting child
- * calls this function.
+ * Whenever para_server accepts an incoming tcp connection on the port it
+ * listens on, it forks and the resulting child calls this function.
  *
- * An RSA-based challenge/response is used to authenticate
- * the peer. It that authentication succeeds, a random
- * session key is generated and sent back to the peer,
- * encrypted with its RSA public key.  From this point on,
- * all transfers are crypted with this session key.
+ * An RSA-based challenge/response is used to authenticate the peer. It that
+ * authentication succeeds, a random session key is generated and sent back to
+ * the peer, encrypted with its RSA public key. From this point on, all
+ * transfers are crypted with this session key.
  *
- * Next it is checked if the peer supplied  a valid server command or a command
- * for the audio file selector.  If yes, and if the user has sufficient
+ * Next it is checked if the peer supplied a valid server command or a command
+ * for the audio file selector. If yes, and if the user has sufficient
  * permissions to execute that command, the function calls the corresponding
  * command handler which does argument checking and further processing.
  *
- * In order to cope with a DOS attacks, a timeout is set up
- * which terminates the function if the connection was not
- * authenticated when the timeout expires.
+ * In order to cope with DOS attacks, a timeout is set up which terminates
+ * the function if the connection was not authenticated when the timeout
+ * expires.
+ *
+ * \return Standard.
  *
- * \sa alarm(2), crypt.c, crypt.h
+ * \sa alarm(2), \ref crypt.c, \ref crypt.h.
  */
-__noreturn void handle_connect(int fd, const char *peername)
+int handle_connect(int fd)
 {
 	int ret;
 	unsigned char rand_buf[CHALLENGE_SIZE + 2 * SESSION_KEY_LEN];
 	unsigned char challenge_hash[HASH_SIZE];
-	char *p, *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
+	char *command = NULL, *buf = para_malloc(HANDSHAKE_BUFSIZE) /* must be on the heap */;
 	size_t numbytes;
-	struct command_context cc_struct = {.peer = peername}, *cc = &cc_struct;
+	struct command_context cc_struct = {.u = NULL}, *cc = &cc_struct;
+	struct iovec iov;
+	struct connection_features cf;
 
 	cc->scc.fd = fd;
 	reset_signals();
@@ -993,8 +923,8 @@ __noreturn void handle_connect(int fd, const char *peername)
 		goto net_err;
 	/* send Welcome message */
 	ret = write_va_buffer(fd, "This is para_server, version "
-		PACKAGE_VERSION  ".\n"
-		"Features: sideband\n"
+		PACKAGE_VERSION ".\n"
+		"Features: sideband,aes_ctr128\n"
 	);
 	if (ret < 0)
 		goto net_err;
@@ -1002,12 +932,9 @@ __noreturn void handle_connect(int fd, const char *peername)
 	ret = recv_buffer(fd, buf, HANDSHAKE_BUFSIZE);
 	if (ret < 0)
 		goto net_err;
-	ret = parse_auth_request(buf, ret, &cc->u, &cc->use_sideband);
+	ret = parse_auth_request(buf, ret, &cc->u, &cf);
 	if (ret < 0)
 		goto net_err;
-	p = buf + strlen(AUTH_REQUEST_MSG);
-	PARA_DEBUG_LOG("received auth request for user %s\n", p);
-	cc->u = lookup_user(p);
 	if (cc->u) {
 		get_random_bytes_or_die(rand_buf, sizeof(rand_buf));
 		ret = pub_encrypt(cc->u->pubkey, rand_buf, sizeof(rand_buf),
@@ -1024,30 +951,18 @@ __noreturn void handle_connect(int fd, const char *peername)
 		numbytes = 256;
 		get_random_bytes_or_die((unsigned char *)buf, numbytes);
 	}
-	PARA_DEBUG_LOG("sending %u byte challenge + rc4 keys (%zu bytes)\n",
+	PARA_DEBUG_LOG("sending %d byte challenge + session key (%zu bytes)\n",
 		CHALLENGE_SIZE, numbytes);
-	if (cc->use_sideband) {
-		struct iovec iov;
-		ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
-		buf = NULL;
-		if (ret < 0)
-			goto net_err;
-		ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
-			HANDSHAKE_BUFSIZE, &iov);
-		if (ret < 0)
-			goto net_err;
-		buf = iov.iov_base;
-		numbytes = iov.iov_len;
-	} else {
-		ret = write_all(fd, buf, numbytes);
-		if (ret < 0)
-			goto net_err;
-		/* recv challenge response */
-		ret = recv_bin_buffer(fd, buf, HASH_SIZE);
-		if (ret < 0)
-			goto net_err;
-		numbytes = ret;
-	}
+	ret = send_sb(&cc->scc, buf, numbytes, SBD_CHALLENGE, false);
+	buf = NULL;
+	if (ret < 0)
+		goto net_err;
+	ret = recv_sb(&cc->scc, SBD_CHALLENGE_RESPONSE,
+		HANDSHAKE_BUFSIZE, &iov);
+	if (ret < 0)
+		goto net_err;
+	buf = iov.iov_base;
+	numbytes = iov.iov_len;
 	PARA_DEBUG_LOG("received %zu bytes challenge response\n", numbytes);
 	ret = -E_BAD_USER;
 	if (!cc->u)
@@ -1067,53 +982,22 @@ __noreturn void handle_connect(int fd, const char *peername)
 	PARA_INFO_LOG("good auth for %s\n", cc->u->name);
 	/* init stream cipher keys with the second part of the random buffer */
 	cc->scc.recv = sc_new(rand_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
-	cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN, SESSION_KEY_LEN);
-	if (cc->use_sideband)
-		ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
-	else
-		ret = sc_send_buffer(&cc->scc, PROCEED_MSG);
+	cc->scc.send = sc_new(rand_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
+		SESSION_KEY_LEN);
+	ret = send_sb(&cc->scc, NULL, 0, SBD_PROCEED, false);
 	if (ret < 0)
 		goto net_err;
-	if (cc->use_sideband) {
-		struct iovec iov;
-		ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
-		if (ret < 0)
-			goto net_err;
-		ret = parse_sb_command(cc, &iov);
-		if (ret < 0)
-			goto err_out;
-		cc->argc = ret;
-	} else {
-		ret = read_command(&cc->scc, &command);
-		if (ret == -E_COMMAND_SYNTAX)
-			goto err_out;
-		if (ret < 0)
-			goto net_err;
-		ret = -E_BAD_CMD;
-		cc->cmd = parse_cmd(command);
-		if (!cc->cmd)
-			goto err_out;
-		/* valid command, check permissions */
-		ret = check_perms(cc->u->perms, cc->cmd);
-		if (ret < 0)
-			goto err_out;
-		/* valid command and sufficient perms */
-		ret = create_argv(command, "\n", &cc->argv);
-		if (ret < 0)
-			goto err_out;
-		cc->argc = ret;
-	}
-	PARA_NOTICE_LOG("calling com_%s() for %s@%s\n", cc->cmd->name,
-		cc->u->name, peername);
-	ret = cc->cmd->handler(cc);
-	free_argv(cc->argv);
-	mutex_lock(mmd_mutex);
-	mmd->num_commands++;
-	mutex_unlock(mmd_mutex);
+	ret = recv_sb(&cc->scc, SBD_COMMAND, MAX_COMMAND_LEN, &iov);
+	if (ret < 0)
+		goto net_err;
+	ret = run_command(cc, &iov);
+	free(iov.iov_base);
+	if (ret < 0)
+		goto err_out;
 	if (ret >= 0)
 		goto out;
 err_out:
-	if (send_strerror(cc, -ret) >= 0 && cc->use_sideband)
+	if (send_strerror(cc, -ret) >= 0)
 		send_sb(&cc->scc, NULL, 0, SBD_EXIT__FAILURE, true);
 net_err:
 	PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
@@ -1121,16 +1005,14 @@ out:
 	free(buf);
 	free(command);
 	mutex_lock(mmd_mutex);
-	if (cc->cmd && (cc->cmd->perms & AFS_WRITE) && ret >= 0)
-		mmd->events++;
 	mmd->active_connections--;
 	mutex_unlock(mmd_mutex);
-	if (ret >= 0 && cc->use_sideband) {
+	if (ret >= 0) {
 		ret = send_sb(&cc->scc, NULL, 0, SBD_EXIT__SUCCESS, true);
 		if (ret < 0)
 			PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
 	}
 	sc_free(cc->scc.recv);
 	sc_free(cc->scc.send);
-	exit(ret < 0? EXIT_FAILURE : EXIT_SUCCESS);
+	return ret;
 }