X-Git-Url: http://git.tuebingen.mpg.de/?a=blobdiff_plain;f=client_common.c;h=39eb8b4cce9f6403132329fd0edfbf7b7025caaf;hb=b1206644af64376f11877f14fa9f9dd3c30f8e4b;hp=b77c192f3a1c31bc0792fd427b39e21518c2fbd1;hpb=c839ef92e35d5604748aa4674b400156ff7baced;p=paraslash.git

diff --git a/client_common.c b/client_common.c
index b77c192f..39eb8b4c 100644
--- a/client_common.c
+++ b/client_common.c
@@ -1,326 +1,658 @@
 /*
- * Copyright (C) 1997-2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997 Andre Noll <maan@tuebingen.mpg.de>
  *
- *     This program is free software; you can redistribute it and/or modify
- *     it under the terms of the GNU General Public License as published by
- *     the Free Software Foundation; either version 2 of the License, or
- *     (at your option) any later version.
- *
- *     This program is distributed in the hope that it will be useful,
- *     but WITHOUT ANY WARRANTY; without even the implied warranty of
- *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *     GNU General Public License for more details.
- *
- *     You should have received a copy of the GNU General Public License
- *     along with this program; if not, write to the Free Software
- *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
+ * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
-/** \file client_common.c common functions of para_client and para_audiod */
+/** \file client_common.c Common functions of para_client and para_audiod. */
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <regex.h>
+#include <sys/types.h>
+#include <arpa/inet.h>
+#include <sys/un.h>
+#include <netdb.h>
+#include <lopsub.h>
 
+#include "client.lsg.h"
 #include "para.h"
+#include "error.h"
 #include "list.h"
 #include "sched.h"
-#include "client.cmdline.h"
 #include "crypt.h"
-#include "rc4.h"
 #include "net.h"
 #include "fd.h"
+#include "sideband.h"
 #include "string.h"
-#include "client.cmdline.h"
 #include "client.h"
-#include "error.h"
+#include "buffer_tree.h"
+#include "version.h"
 
-void rc4_send(unsigned long len, const unsigned char *indata,
-		unsigned char *outdata, void *private_data)
-{
-	struct private_client_data *pcd = private_data;
-	RC4(&pcd->rc4_send_key, len, indata, outdata);
-}
-
-void rc4_recv(unsigned long len, const unsigned char *indata,
-		unsigned char *outdata, void *private_data)
-{
-	struct private_client_data *pcd = private_data;
-	RC4(&pcd->rc4_recv_key, len, indata, outdata);
-}
+/** The size of the receiving buffer. */
+#define CLIENT_BUFSIZE 4000
 
-
-void client_close(struct private_client_data *pcd)
+/**
+ * Close the connection to para_server and free all resources.
+ *
+ * \param ct Pointer to the client data.
+ *
+ * \sa \ref client_open().
+ */
+void client_close(struct client_task *ct)
 {
-	if (pcd)
+	if (!ct)
 		return;
-	if (pcd->fd >= 0) {
-		disable_crypt(pcd->fd);
-		close(pcd->fd);
-	}
-	free(pcd->user);
-	free(pcd->config_file);
-	free(pcd->key_file);
-	free(pcd);
+	free(ct->user);
+	free(ct->config_file);
+	free(ct->key_file);
+	lls_free_parse_result(ct->lpr, CLIENT_CMD_PTR);
+	free(ct->challenge_hash);
+	sb_free(ct->sbc[0]);
+	sb_free(ct->sbc[1]);
+	free(ct);
 }
 
-int client_parse_config(int argc, char *argv[],
-		struct private_client_data **pcd_ptr)
+/*
+ * The preselect hook for server commands.
+ *
+ * The task pointer must contain a pointer to the initialized client data
+ * structure as it is returned by client_open().
+ *
+ * This function checks the state of the connection and adds the file descriptor
+ * of the connection to the read or write fd set of s accordingly.
+ */
+static void client_pre_select(struct sched *s, void *context)
 {
-	char *home = para_homedir();
-	struct stat statbuf;
 	int ret;
-	struct private_client_data *pcd =
-		para_calloc(sizeof(struct private_client_data));
+	struct client_task *ct = context;
 
-	pcd->fd = -1;
-	client_cmdline_parser(argc, argv, &pcd->conf);
-	ret = - E_CLIENT_SYNTAX;
-	if (!pcd->conf.inputs_num)
-		goto out;
-	pcd->user = pcd->conf.user_given?
-		para_strdup(pcd->conf.user_arg) : para_logname();
-
-	pcd->key_file = pcd->conf.key_file_given?
-		para_strdup(pcd->conf.key_file_arg) :
-		make_message("%s/.paraslash/key.%s", home, pcd->user);
-
-	pcd->config_file = pcd->conf.config_file_given?
-		para_strdup(pcd->conf.config_file_arg) :
-		make_message("%s/.paraslash/client.conf", home);
-	ret = stat(pcd->config_file, &statbuf);
-	if (ret && pcd->conf.config_file_given) {
-		ret = -E_NO_CONFIG;
-		goto out;
-	}
-	if (!ret)
-		client_cmdline_parser_configfile(pcd->config_file,
-			&pcd->conf, 0, 0, 0);
-	ret = 1;
-	*pcd_ptr = pcd;
-	PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
-	PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
-	PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
-	PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
-		pcd->conf.server_port_arg);
-out:
-	free(home);
-	if (ret < 0)
-		client_close(pcd);
-	return ret;
-}
-
-void client_pre_select(struct sched *s, struct task *t)
-{
-	struct private_client_data *pcd = t->private_data;
-
-	t->ret = 1;
-	pcd->check_r = 0;
-	pcd->check_w = 0;
-	if (pcd->fd < 0)
+	if (ct->scc.fd < 0)
 		return;
-	switch (pcd->status) {
+	switch (ct->status) {
 	case CL_CONNECTED:
 	case CL_SENT_AUTH:
 	case CL_SENT_CH_RESPONSE:
-	case CL_SENT_COMMAND:
-		para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
-		pcd->check_r = 1;
+		para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 		return;
 
 	case CL_RECEIVED_WELCOME:
-	case CL_RECEIVED_CHALLENGE:
 	case CL_RECEIVED_PROCEED:
-		para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
-		pcd->check_w = 1;
+	case CL_RECEIVED_CHALLENGE:
+		para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
 		return;
 
-	case CL_RECEIVING:
-		if (pcd->loaded < CLIENT_BUFSIZE - 1) {
-			para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
-			pcd->check_r = 1;
-		}
-		return;
 	case CL_SENDING:
-		if (*pcd->in_loaded) {
-			PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
-			para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
-			pcd->check_w = 1;
-		} else {
-			if (*pcd->in_eof) {
-				t->ret = -E_INPUT_EOF;
-				s->timeout.tv_sec = 0;
-				s->timeout.tv_usec = 1;
-			}
+		if (ct->btrn[1]) {
+			ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
+			if (ret < 0)
+				sched_min_delay(s);
+			else if (ret > 0)
+				para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
+		}
+		/* fallthrough */
+	case CL_EXECUTING:
+		if (ct->btrn[0]) {
+			ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
+			if (ret < 0)
+				sched_min_delay(s);
+			else if (ret > 0)
+				para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
 		}
 		return;
 	}
 }
 
-static ssize_t client_recv_buffer(struct private_client_data *pcd)
+static int send_sb(struct client_task *ct, int channel, void *buf, size_t numbytes,
+		enum sb_designator band, bool dont_free)
+{
+	int ret, fd = ct->scc.fd;
+	struct iovec iov[2];
+
+	if (!ct->sbc[channel]) {
+		struct sb_buffer sbb;
+		sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
+			NULL : sc_trafo;
+		sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
+		ct->sbc[channel] = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
+	}
+	ret = sb_get_send_buffers(ct->sbc[channel], iov);
+	ret = xwritev(fd, iov, ret);
+	if (ret < 0) {
+		sb_free(ct->sbc[channel]);
+		ct->sbc[channel] = NULL;
+		return ret;
+	}
+	if (sb_sent(ct->sbc[channel], ret)) {
+		ct->sbc[channel] = NULL;
+		return 1;
+	}
+	return 0;
+}
+
+static int recv_sb(struct client_task *ct, fd_set *rfds,
+		struct sb_buffer *result)
+{
+	int ret;
+	size_t n;
+	sb_transformation trafo;
+	void *trafo_context;
+	struct iovec iov;
+
+	if (!FD_ISSET(ct->scc.fd, rfds))
+		return 0;
+	if (ct->status < CL_SENT_CH_RESPONSE)
+		trafo = trafo_context = NULL;
+	else {
+		trafo = sc_trafo;
+		trafo_context = ct->scc.recv;
+	}
+	if (!ct->sbc[0])
+		ct->sbc[0] = sb_new_recv(0, trafo, trafo_context);
+again:
+	sb_get_recv_buffer(ct->sbc[0], &iov);
+	ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
+	if (ret < 0) {
+		sb_free(ct->sbc[0]);
+		ct->sbc[0] = NULL;
+		return ret;
+	}
+	if (n == 0)
+		return 0;
+	ret = sb_received(ct->sbc[0], n, result);
+	if (ret < 0)
+		return ret;
+	if (ret == 0)
+		goto again;
+	ct->sbc[0] = NULL;
+	return 1;
+}
+
+
+static char **parse_features(char *buf)
+{
+	int i;
+	const char id[] = "\nFeatures: ";
+	char *p, *q, **features;
+
+	p = strstr(buf, id);
+	if (!p)
+		return NULL;
+	p += strlen(id);
+	q = strchr(p, '\n');
+	if (!q)
+		return NULL;
+	*q = '\0';
+	create_argv(p, ",", &features);
+	for (i = 0; features[i]; i++)
+		PARA_INFO_LOG("server feature: %s\n", features[i]);
+	return features;
+}
+
+static int dispatch_sbb(struct client_task *ct, struct sb_buffer *sbb)
 {
-	ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
-		CLIENT_BUFSIZE - pcd->loaded);
-	if (!ret)
-		return -E_SERVER_EOF;
-	if (ret > 0)
-		pcd->loaded += ret;
+	int ret;
+	const char *designator[] = {SB_DESIGNATORS_ARRAY};
+
+	if (!sbb)
+		return 0;
+	if (sbb->band < NUM_SB_DESIGNATORS)
+		PARA_DEBUG_LOG("band: %s\n", designator[sbb->band]);
+
+	switch (sbb->band) {
+	case SBD_AWAITING_DATA:
+		ct->status = CL_SENDING;
+		ret = 1;
+		goto out;
+	case SBD_OUTPUT:
+		if (iov_valid(&sbb->iov))
+			btr_add_output(sbb->iov.iov_base, sbb->iov.iov_len,
+				ct->btrn[0]);
+		ret = 1;
+		goto out;
+	case SBD_DEBUG_LOG:
+	case SBD_INFO_LOG:
+	case SBD_NOTICE_LOG:
+	case SBD_WARNING_LOG:
+	case SBD_ERROR_LOG:
+	case SBD_CRIT_LOG:
+	case SBD_EMERG_LOG:
+		if (iov_valid(&sbb->iov)) {
+			int ll = sbb->band - SBD_DEBUG_LOG;
+			para_log(ll, "remote: %s", (char *)sbb->iov.iov_base);
+		}
+		ret = 1;
+		goto deallocate;
+	case SBD_EXIT__SUCCESS:
+		ret = -E_SERVER_CMD_SUCCESS;
+		goto deallocate;
+	case SBD_EXIT__FAILURE:
+		ret = -E_SERVER_CMD_FAILURE;
+		goto deallocate;
+	default:
+		PARA_ERROR_LOG("invalid band %d\n", sbb->band);
+		ret = -E_BAD_BAND;
+		goto deallocate;
+	}
+deallocate:
+	free(sbb->iov.iov_base);
+out:
+	sbb->iov.iov_base = NULL;
 	return ret;
+}
 
+static int send_sb_command(struct client_task *ct)
+{
+	int i;
+	char *command, *p;
+	size_t len = 0;
+	unsigned num_inputs = lls_num_inputs(ct->lpr);
+
+	if (ct->sbc[1])
+		return send_sb(ct, 0, NULL, 0, 0, false);
+
+	for (i = 0; i < num_inputs; i++)
+		len += strlen(lls_input(i, ct->lpr)) + 1;
+	p = command = para_malloc(len);
+	for (i = 0; i < num_inputs; i++) {
+		const char *str = lls_input(i, ct->lpr);
+		strcpy(p, str);
+		p += strlen(str) + 1;
+	}
+	PARA_DEBUG_LOG("--> %s\n", command);
+	return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 }
 
-void client_post_select(struct sched *s, struct task *t)
+/*
+ * The post select hook for client commands.
+ *
+ * Depending on the current state of the connection and the status of the read
+ * and write fd sets of s, this function performs the necessary steps to
+ * authenticate the connection, to send the command given by t->private_data
+ * and to receive para_server's output, if any.
+ */
+static int client_post_select(struct sched *s, void *context)
 {
-	struct private_client_data *pcd = t->private_data;
+	struct client_task *ct = context;
+	int ret = 0;
+	size_t n;
+	char buf[CLIENT_BUFSIZE];
 
-//	PARA_INFO_LOG("status %d\n", pcd->status);
-	t->ret = 1;
-	if (pcd->fd < 0)
-		return;
-	if (!pcd->check_r && !pcd->check_w)
-		return;
-	if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
-		return;
-	if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
-		return;
-	switch (pcd->status) {
+	ret = task_get_notification(ct->task);
+	if (ret < 0)
+		goto out;
+	if (ct->scc.fd < 0)
+		return 0;
+	switch (ct->status) {
 	case CL_CONNECTED: /* receive welcome message */
-		t->ret = client_recv_buffer(pcd);
-		if (t->ret > 0)
-			pcd->status = CL_RECEIVED_WELCOME;
-		return;
+		ret = read_nonblock(ct->scc.fd, buf, sizeof(buf), &s->rfds, &n);
+		if (ret < 0 || n == 0)
+			goto out;
+		ct->features = parse_features(buf);
+		ct->status = CL_RECEIVED_WELCOME;
+		return 0;
 	case CL_RECEIVED_WELCOME: /* send auth command */
-		sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
-			"" : "rc4 ", pcd->user);
-		PARA_INFO_LOG("--> %s\n", pcd->buf);
-		t->ret = send_buffer(pcd->fd, pcd->buf);
-		if (t->ret >= 0)
-			pcd->status = CL_SENT_AUTH;
-		return;
-	case CL_SENT_AUTH: /* receive challenge number */
-		pcd->loaded = 0;
-		t->ret = client_recv_buffer(pcd);
-		if (t->ret < 0)
-			return;
-		if (t->ret != 64) {
-			t->ret = -E_INVALID_CHALLENGE;
-			PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
-			return;
+		if (!FD_ISSET(ct->scc.fd, &s->wfds))
+			return 0;
+		sprintf(buf, AUTH_REQUEST_MSG "%s sideband,aes_ctr128",
+			ct->user);
+		PARA_INFO_LOG("--> %s\n", buf);
+		ret = write_buffer(ct->scc.fd, buf);
+		if (ret < 0)
+			goto out;
+		ct->status = CL_SENT_AUTH;
+		return 0;
+	case CL_SENT_AUTH:
+		/*
+		 * Receive challenge and session keys, decrypt the challenge and
+		 * send back the hash of the decrypted challenge.
+		 */
+		{
+		/* decrypted challenge/session key buffer */
+		unsigned char crypt_buf[1024];
+		struct sb_buffer sbb;
+
+		ret = recv_sb(ct, &s->rfds, &sbb);
+		if (ret <= 0)
+			goto out;
+		if (sbb.band != SBD_CHALLENGE) {
+			ret = -E_BAD_BAND;
+			free(sbb.iov.iov_base);
+				goto out;
 		}
-		PARA_INFO_LOG("%s", "<-- [challenge]\n");
-		/* decrypt challenge number */
-		t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
-			(unsigned char *) pcd->buf, 64);
-		if (t->ret > 0)
-			pcd->status = CL_RECEIVED_CHALLENGE;
-		return;
-	case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
-		PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
-		t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
-			pcd->challenge_nr);
-		if (t->ret > 0)
-			pcd->status = CL_SENT_CH_RESPONSE;
-		return;
+		n = sbb.iov.iov_len;
+		PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
+		ret = priv_decrypt(ct->key_file, crypt_buf,
+			sbb.iov.iov_base, n);
+		free(sbb.iov.iov_base);
+		if (ret < 0)
+			goto out;
+		ct->challenge_hash = para_malloc(HASH_SIZE);
+		hash_function((char *)crypt_buf, CHALLENGE_SIZE, ct->challenge_hash);
+		ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
+		ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
+			SESSION_KEY_LEN);
+		hash_to_asc(ct->challenge_hash, buf);
+		PARA_INFO_LOG("--> %s\n", buf);
+		ct->status = CL_RECEIVED_CHALLENGE;
+		return 0;
+		}
+	case CL_RECEIVED_CHALLENGE:
+		ret = send_sb(ct, 0, ct->challenge_hash, HASH_SIZE,
+			SBD_CHALLENGE_RESPONSE, false);
+		if (ret != 0)
+			ct->challenge_hash = NULL;
+		if (ret <= 0)
+			goto out;
+		ct->status = CL_SENT_CH_RESPONSE;
+		goto out;
 	case CL_SENT_CH_RESPONSE: /* read server response */
 		{
-		size_t bytes_received;
-		unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
-		pcd->loaded = 0;
-		t->ret = client_recv_buffer(pcd);
-		if (t->ret < 0)
-			return;
-		bytes_received = t->ret;
-		PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
-			"info ++++\n", pcd->buf);
-		/* check if server has sent "Proceed" message */
-		t->ret = -E_CLIENT_AUTH;
-		if (!strstr(pcd->buf, PROCEED_MSG))
-			return;
-		t->ret = 1;
-		pcd->status = CL_RECEIVED_PROCEED;
-		if (bytes_received < PROCEED_MSG_LEN + 32)
-			return;
-		PARA_INFO_LOG("%s", "decrypting session key\n");
-		t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
-			(unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
-			bytes_received - PROCEED_MSG_LEN - 1);
-		if (t->ret < 0)
-			return;
-		RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
-		RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
-		enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
+		struct sb_buffer sbb;
+		ret = recv_sb(ct, &s->rfds, &sbb);
+		if (ret <= 0)
+			goto out;
+		free(sbb.iov.iov_base);
+		if (sbb.band != SBD_PROCEED)
+			ret = -E_BAD_BAND;
+		else
+			ct->status = CL_RECEIVED_PROCEED;
+		goto out;
 		}
 	case CL_RECEIVED_PROCEED: /* concat args and send command */
 		{
-		int i;
-		char *command = NULL;
-		for (i = 0; i < pcd->conf.inputs_num; i++) {
-			char *tmp = command;
-			command = make_message("%s\n%s", command?
-				command : "", pcd->conf.inputs[i]);
-			free(tmp);
+		if (!FD_ISSET(ct->scc.fd, &s->wfds))
+			return 0;
+		ret = send_sb_command(ct);
+		if (ret <= 0)
+			goto out;
+		ct->status = CL_EXECUTING;
+		return 0;
 		}
-		command = para_strcat(command, EOC_MSG "\n");
-		PARA_DEBUG_LOG("--> %s\n", command);
-		t->ret = send_buffer(pcd->fd, command);
-		free(command);
-		if (t->ret > 0)
-			pcd->status = CL_SENT_COMMAND;
-		return;
+	case CL_SENDING:
+		if (ct->btrn[1]) {
+			char *buf2;
+			size_t sz;
+			ret = btr_node_status(ct->btrn[1], 0, BTR_NT_LEAF);
+			if (ret == -E_BTR_EOF) {
+				/* empty blob data packet indicates EOF */
+				PARA_INFO_LOG("blob sent\n");
+				ret = send_sb(ct, 1, NULL, 0, SBD_BLOB_DATA, true);
+				if (ret >= 0)
+					ret = -E_BTR_EOF;
+			}
+			if (ret < 0)
+				goto close1;
+			if (ret > 0 && FD_ISSET(ct->scc.fd, &s->wfds)) {
+				sz = btr_next_buffer(ct->btrn[1], &buf2);
+				assert(sz);
+				ret = send_sb(ct, 1, buf2, sz, SBD_BLOB_DATA, true);
+				if (ret < 0)
+					goto close1;
+				if (ret > 0)
+					btr_consume(ct->btrn[1], sz);
+			}
 		}
-	case CL_SENT_COMMAND:
-		pcd->loaded = 0;
-		t->ret = client_recv_buffer(pcd);
-		if (t->ret < 0)
-			return;
-		t->ret = -E_HANDSHAKE_COMPLETE;
-		if (strstr(pcd->buf, AWAITING_DATA_MSG))
-			pcd->status = CL_SENDING;
-		else
-			pcd->status = CL_RECEIVING;
-		return;
-	case CL_SENDING: /* FIXME: might block */
-		PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
-		t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
-		if (t->ret <= 0) {
-			if (!t->ret)
-				t->ret = 1;
-			return;
+		/* fall through */
+	case CL_EXECUTING:
+		if (ct->btrn[0]) {
+			ret = btr_node_status(ct->btrn[0], 0, BTR_NT_ROOT);
+			if (ret < 0)
+				goto close0;
+			if (ret > 0 && FD_ISSET(ct->scc.fd, &s->rfds)) {
+				struct sb_buffer sbb;
+				ret = recv_sb(ct, &s->rfds, &sbb);
+				if (ret < 0)
+					goto close0;
+				if (ret > 0) {
+					ret = dispatch_sbb(ct, &sbb);
+					if (ret < 0)
+						goto close0;
+				}
+			}
 		}
-		*pcd->in_loaded = 0; /* FIXME: short writes */
-		return;
-	case CL_RECEIVING:
-		t->ret = client_recv_buffer(pcd);
-		return;
+		ret = 0;
+		goto out;
 	}
-
+close1:
+	PARA_INFO_LOG("channel 1: %s\n", para_strerror(-ret));
+	btr_remove_node(&ct->btrn[1]);
+	if (ct->btrn[0])
+		return 0;
+	goto out;
+close0:
+	PARA_INFO_LOG("channel 0: %s\n", para_strerror(-ret));
+	btr_remove_node(&ct->btrn[0]);
+	if (ct->btrn[1] && ct->status == CL_SENDING)
+		return 0;
+out:
+	if (ret >= 0)
+		return 0;
+	btr_remove_node(&ct->btrn[0]);
+	btr_remove_node(&ct->btrn[1]);
+	if (ret != -E_SERVER_CMD_SUCCESS && ret != -E_SERVER_CMD_FAILURE)
+		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+	if (ct->scc.fd >= 0) {
+		close(ct->scc.fd);
+		ct->scc.fd = -1;
+	}
+	free_argv(ct->features);
+	ct->features = NULL;
+	sc_free(ct->scc.recv);
+	ct->scc.recv = NULL;
+	sc_free(ct->scc.send);
+	ct->scc.send = NULL;
+	return ret;
 }
 
-int client_open(struct private_client_data *pcd)
+/**
+ * Connect to para_server and register the client task.
+ *
+ * \param ct The initialized client task structure.
+ * \param s The scheduler instance to register the client task to.
+ * \param parent The parent node of the client btr node.
+ * \param child The child node of the client node.
+ *
+ * The client task structure given by \a ct  must be allocated and initialized
+ * by \ref client_parse_config() before this function is called.
+ *
+ * \return Standard.
+ */
+int client_connect(struct client_task *ct, struct sched *s,
+		struct btr_node *parent, struct btr_node *child)
 {
 	int ret;
-	struct hostent *he;
-	struct sockaddr_in their_addr;
+	const char *host = CLIENT_OPT_STRING_VAL(HOSTNAME, ct->lpr);
+	uint32_t port = CLIENT_OPT_UINT32_VAL(SERVER_PORT, ct->lpr);
 
-	ret = get_host_info(pcd->conf.hostname_arg, &he);
-	if (ret < 0)
-		goto out;
-	/* get new socket */
-	ret = get_socket();
+	PARA_NOTICE_LOG("connecting %s:%u\n", host, port);
+	ct->scc.fd = -1;
+	ret = para_connect_simple(IPPROTO_TCP, host, port);
 	if (ret < 0)
-		goto out;
-	pcd->fd = ret;
-	/* init their_addr */
-	init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
-	ret = para_connect(pcd->fd, &their_addr);
+		return ret;
+	ct->scc.fd = ret;
+	ret = mark_fd_nonblocking(ct->scc.fd);
 	if (ret < 0)
-		goto out;
-	pcd->status = CL_CONNECTED;
-	ret = mark_fd_nonblock(pcd->fd);
+		goto err_out;
+	ct->status = CL_CONNECTED;
+	ct->btrn[0] = btr_new_node(&(struct btr_node_description)
+		EMBRACE(.name = "client recv", .parent = NULL, .child = child));
+	ct->btrn[1] = btr_new_node(&(struct btr_node_description)
+		EMBRACE(.name = "client send", .parent = parent, .child = NULL));
+
+	ct->task = task_register(&(struct task_info) {
+		.name = "client",
+		.pre_select = client_pre_select,
+		.post_select = client_post_select,
+		.context = ct,
+	}, s);
+	return 1;
+err_out:
+	close(ct->scc.fd);
+	ct->scc.fd = -1;
+	return ret;
+}
+
+static void handle_help_flag(struct lls_parse_result *lpr)
+{
+	char *help;
+
+	if (CLIENT_OPT_GIVEN(DETAILED_HELP, lpr))
+		help = lls_long_help(CLIENT_CMD_PTR);
+	else if (CLIENT_OPT_GIVEN(HELP, lpr))
+		help = lls_short_help(CLIENT_CMD_PTR);
+	else
+		return;
+	printf("%s\n", help);
+	free(help);
+	exit(EXIT_SUCCESS);
+}
+
+/**
+ * Parse a client configuration.
+ *
+ * \param argc Usual argument count.
+ * \param argv Usual argument vector.
+ * \param ct_ptr Filled in by this function.
+ * \param loglevel If not \p NULL, the number of the loglevel is stored here.
+ *
+ * This checks the command line options given by \a argc and \a argv, sets
+ * default values for the user name and the name of the rsa key file and reads
+ * further options from the config file.
+ *
+ * Upon successful return, \a ct_ptr points to a dynamically allocated and
+ * initialized client task struct.
+ *
+ * \return The number of non-option arguments in \a argc/argv on success,
+ * negative on errors.
+ */
+int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
+		int *loglevel)
+{
+	const struct lls_command *cmd = CLIENT_CMD_PTR;
+	void *map;
+	size_t sz;
+	struct lls_parse_result *lpr;
+	int ret, ll;
+	struct client_task *ct;
+	char *cf = NULL, *kf = NULL, *user, *errctx, *home = para_homedir();
+
+	ret = lls(lls_parse(argc, argv, cmd, &lpr, &errctx));
 	if (ret < 0)
 		goto out;
-	pcd->task.pre_select = client_pre_select;
-	pcd->task.post_select = client_post_select;
-	pcd->task.private_data = pcd;
-	sprintf(pcd->task.status, "client");
-	register_task(&pcd->task);
-	ret = 1;
+	ll = CLIENT_OPT_UINT32_VAL(LOGLEVEL, lpr);
+	version_handle_flag("client", CLIENT_OPT_GIVEN(VERSION, lpr));
+	handle_help_flag(lpr);
+
+	if (CLIENT_OPT_GIVEN(CONFIG_FILE, lpr))
+		cf = para_strdup(CLIENT_OPT_STRING_VAL(CONFIG_FILE, lpr));
+	else
+		cf = make_message("%s/.paraslash/client.conf", home);
+	ret = mmap_full_file(cf, O_RDONLY, &map, &sz, NULL);
+	if (ret < 0) {
+		if (ret != -E_EMPTY && ret != -ERRNO_TO_PARA_ERROR(ENOENT))
+			goto out;
+		if (ret == -ERRNO_TO_PARA_ERROR(ENOENT) &&
+				CLIENT_OPT_GIVEN(CONFIG_FILE, lpr))
+			goto out;
+	} else {
+		int cf_argc;
+		char **cf_argv;
+		struct lls_parse_result *cf_lpr, *merged_lpr;
+		ret = lls(lls_convert_config(map, sz, NULL, &cf_argv, &errctx));
+		para_munmap(map, sz);
+		if (ret < 0)
+			goto out;
+		cf_argc = ret;
+		ret = lls(lls_parse(cf_argc, cf_argv, cmd, &cf_lpr, &errctx));
+		lls_free_argv(cf_argv);
+		if (ret < 0)
+			goto out;
+		ret = lls(lls_merge(lpr, cf_lpr, cmd, &merged_lpr,
+			&errctx));
+		lls_free_parse_result(cf_lpr, cmd);
+		if (ret < 0)
+			goto out;
+		lls_free_parse_result(lpr, cmd);
+		lpr = merged_lpr;
+	}
+	/* success */
+	user = CLIENT_OPT_GIVEN(USER, lpr)?
+		para_strdup(CLIENT_OPT_STRING_VAL(USER, lpr)) : para_logname();
+
+	if (CLIENT_OPT_GIVEN(KEY_FILE, lpr))
+		kf = para_strdup(CLIENT_OPT_STRING_VAL(KEY_FILE, lpr));
+	else {
+		kf = make_message("%s/.paraslash/key.%s", home, user);
+		if (!file_exists(kf)) {
+			free(kf);
+			kf = make_message("%s/.ssh/id_rsa", home);
+		}
+	}
+	PARA_INFO_LOG("user: %s\n", user);
+	PARA_INFO_LOG("config file: %s\n", cf);
+	PARA_INFO_LOG("key file: %s\n", kf);
+	PARA_INFO_LOG("loglevel: %d\n", ll);
+	ct = para_calloc(sizeof(*ct));
+	ct->scc.fd = -1;
+	ct->lpr = lpr;
+	ct->key_file = kf;
+	ct->config_file = cf;
+	ct->user = user;
+	*ct_ptr = ct;
+	if (loglevel)
+		*loglevel = ll;
+	ret = lls_num_inputs(lpr);
 out:
+	free(home);
+	if (ret < 0) {
+		if (errctx)
+			PARA_ERROR_LOG("%s\n", errctx);
+		free(errctx);
+		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+		lls_free_parse_result(lpr, cmd);
+		free(cf);
+		free(kf);
+		*ct_ptr = NULL;
+	}
+	return ret;
+}
+
+/**
+ * Parse the client configuration and open a connection to para_server.
+ *
+ * \param argc See \ref client_parse_config.
+ * \param argv See \ref client_parse_config.
+ * \param ct_ptr See \ref client_parse_config.
+ * \param loglevel See \ref client_parse_config.
+ * \param parent See \ref client_connect().
+ * \param child See \ref client_connect().
+ * \param sched See \ref client_connect().
+ *
+ * This function combines client_parse_config() and client_connect(). It is
+ * considered a syntax error if no command was given, i.e. if the number
+ * of non-option arguments is zero.
+ *
+ * \return Standard.
+ */
+int client_open(int argc, char *argv[], struct client_task **ct_ptr,
+		int *loglevel, struct btr_node *parent, struct btr_node *child,
+		struct sched *sched)
+{
+	int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
+
+	if (ret < 0)
+		return ret;
+	if (ret == 0) {
+		ret = -E_CLIENT_SYNTAX;
+		goto fail;
+	}
+	ret = client_connect(*ct_ptr, sched, parent, child);
+	if (ret < 0)
+		goto fail;
+	return 1;
+fail:
+	client_close(*ct_ptr);
+	*ct_ptr = NULL;
 	return ret;
 }