X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=client_common.c;h=c19b71218b59f62f1e6a75c1eee43ee332a65900;hp=88cbf51ec43757aad074468494f096d62b3c0b59;hb=21422ac8abf41c45b3a611f97486afd8479fce38;hpb=471684761a2039bbc89aa1e3c33c62de6bef86cf

diff --git a/client_common.c b/client_common.c
index 88cbf51e..c19b7121 100644
--- a/client_common.c
+++ b/client_common.c
@@ -1,183 +1,85 @@
 /*
- * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 1997-2013 Andre Noll <maan@systemlinux.org>
  *
  * 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 <regex.h>
+#include <sys/types.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"
+#include "ggo.h"
 
-/*
- * rc4 encrypt data before sending
- *
- * \param len the number of bytes to encrypt
- * \param indata pointer to the input data of length \a len to be encrypted
- * \param outdata pointer that holds the encrypted data after return
- * \param private_data pointer to the private client data containing
- * the rc4 key
- * */
-static 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);
-}
-
-/*
- * rc4 decrypt received data
- *
- * \param len the number of bytes to decrypt
- * \param indata pointer to the input data of length \a len
- * \param outdata pointer that holds the decrypted data after return
- * \param private_data pointer to the private client data containing
- * the rc4 key
- * */
-static 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
 
 /**
- * close the connection to para_server and free all resources
+ * Close the connection to para_server and deallocate per-command resources.
  *
- * \param pcd pointer to the client data
+ * \param ct The client task.
  *
- * \sa client_open.
- * */
-void client_close(struct private_client_data *pcd)
+ * This frees all resources of the current command but keeps the configuration
+ * in \p ct->conf.
+ *
+ * \sa \ref client_close().
+ */
+void client_disconnect(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);
-	client_cmdline_parser_free(&pcd->conf);
-	free(pcd);
-}
-
-static int client_connect(struct private_client_data *pcd)
-{
-	int ret;
-	struct hostent *he;
-	struct sockaddr_in their_addr;
-
-	pcd->fd = -1;
-	ret = get_host_info(pcd->conf.hostname_arg, &he);
-	if (ret < 0)
-		return ret;
-	/* get new socket */
-	ret = get_socket();
-	if (ret < 0)
-		return ret;
-	pcd->fd = ret;
-	/* init their_addr */
-	init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
-	ret = para_connect(pcd->fd, &their_addr);
-	if (ret < 0)
-		goto err_out;
-	pcd->status = CL_CONNECTED;
-	ret = mark_fd_nonblock(pcd->fd);
-	if (ret < 0)
-		goto err_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);
-	return 1;
-err_out:
-	close(pcd->fd);
-	pcd->fd = -1;
-	return ret;
+	if (ct->scc.fd >= 0)
+		close(ct->scc.fd);
+	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;
+	btr_remove_node(&ct->btrn[0]);
+	btr_remove_node(&ct->btrn[1]);
 }
 
 /**
- * open connection to para_server
- *
- * \param argc usual argument count
- * \param argv usual argument vector
- * \param pcd_ptr points to dynamically allocated and initialized private client data
- * upon successful return
+ * Close the connection to para_server and free all resources.
  *
- * Check the command line options given by \a argc and argv, set default values
- * for user name and rsa key file, read further option from the config file.
- * Finally, establish a connection to para_server.
+ * \param ct Pointer to the client data.
  *
- * \return Positive on success, negative on errors.
+ * \sa \ref client_open(), \ref client_disconnect().
  */
-int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
+void client_close(struct client_task *ct)
 {
-	char *home = para_homedir();
-	struct stat statbuf;
-	int ret;
-	struct private_client_data *pcd =
-		para_calloc(sizeof(struct private_client_data));
-
-	*pcd_ptr = pcd;
-	pcd->fd = -1;
-	ret = client_cmdline_parser(argc, argv, &pcd->conf);
-	HANDLE_VERSION_FLAG("client", 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;
-	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);
-	ret = client_connect(pcd);
-out:
-	free(home);
-	if (ret < 0) {
-		PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
-		client_close(pcd);
-		*pcd_ptr = NULL;
-	}
-	return ret;
+	if (!ct)
+		return;
+	client_disconnect(ct);
+	free(ct->user);
+	free(ct->config_file);
+	free(ct->key_file);
+	client_cmdline_parser_free(&ct->conf);
+	free(ct->challenge_hash);
+	sb_free(ct->sbc[0]);
+	sb_free(ct->sbc[1]);
+	free(ct);
 }
 
 /**
- * the preselect hook for server commands
+ * The preselect hook for server commands.
  *
- * \param s pointer to the scheduler
- * \param t pointer to the task struct for this command
+ * \param s Pointer to the scheduler.
+ * \param t Pointer to the task struct for this command.
  *
  * The task pointer must contain a pointer to the initialized client data
  * structure as it is returned by client_open().
@@ -185,199 +87,565 @@ out:
  * This function checks the state of the connection and adds the file descriptor
  * of the connection to the read or write fd set of \a s accordingly.
  *
- * \sa register_task() client_open(), struct sched, struct task
+ * \sa register_task() client_open(), struct sched, struct task.
  */
-void client_pre_select(struct sched *s, struct task *t)
+static void client_pre_select(struct sched *s, struct task *t)
 {
-	struct private_client_data *pcd = t->private_data;
+	int ret;
+	struct client_task *ct = container_of(t, struct client_task, task);
 
-	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);
+		}
+		/* fall though */
+	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;
+	if (!sb_received(ct->sbc[0], n, result))
+		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 bool has_feature(const char *feature, struct client_task *ct)
+{
+	return find_arg(feature, ct->features) >= 0? true : false;
+}
+
+static int send_sb_command(struct client_task *ct)
+{
+	int i;
+	char *command, *p;
+	size_t len = 0;
+
+	if (ct->sbc[1])
+		return send_sb(ct, 0, NULL, 0, 0, false);
 
+	for (i = 0; i < ct->conf.inputs_num; i++)
+		len += strlen(ct->conf.inputs[i]) + 1;
+	p = command = para_malloc(len);
+	for (i = 0; i < ct->conf.inputs_num; i++) {
+		strcpy(p, ct->conf.inputs[i]);
+		p += strlen(ct->conf.inputs[i]) + 1;
+	}
+	PARA_DEBUG_LOG("--> %s\n", command);
+	return send_sb(ct, 0, command, len, SBD_COMMAND, false);
 }
 
 /**
- * the post select hook for client commands
+ * The post select hook for client commands.
  *
- * \param s pointer to the scheduler
- * \param t pointer to the task struct for this command
+ * \param s Pointer to the scheduler.
+ * \param t Pointer to the task struct for this command.
  *
  * Depending on the current state of the connection and the status of the read
- * and write fd sets of \a s, this function performs the neccessary steps to
- * authenticate the connection, to send the commmand given by \a
- * t->private_data and to receive para_server's output, if any.
+ * and write fd sets of \a s, this function performs the necessary steps to
+ * authenticate the connection, to send the command given by \a t->private_data
+ * and to receive para_server's output, if any.
  *
- * \sa struct sched, struct task
+ * \sa struct sched, struct task.
  */
-void client_post_select(struct sched *s, struct task *t)
+static int client_post_select(struct sched *s, struct task *t)
 {
-	struct private_client_data *pcd = t->private_data;
+	struct client_task *ct = container_of(t, struct client_task, task);
+	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(t);
+	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);
+		if (!has_feature("sideband", ct)) {
+			PARA_ERROR_LOG("server has no sideband support\n");
+			ret = -E_INCOMPAT_FEAT;
+			goto out;
+		}
+		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", 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)
-			return;
-		*pcd->in_loaded = 0; /* FIXME: short writes */
-		return;
-	case CL_RECEIVING:
-		t->ret = client_recv_buffer(pcd);
-		return;
+		/* fall though */
+	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;
+				}
+			}
+		}
+		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));
+	return ret;
+}
+
+/**
+ * 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;
+
+	PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
+		ct->conf.server_port_arg);
+	ct->scc.fd = -1;
+	ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
+					       ct->conf.server_port_arg);
+	if (ret < 0)
+		return ret;
+	ct->scc.fd = ret;
+	ret = mark_fd_nonblocking(ct->scc.fd);
+	if (ret < 0)
+		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.pre_select = client_pre_select;
+	ct->task.post_select = client_post_select;
+	ct->task.error = 0;
+	sprintf(ct->task.status, "client");
+	register_task(s, &ct->task);
+	return 1;
+err_out:
+	close(ct->scc.fd);
+	ct->scc.fd = -1;
+	return ret;
+}
+
+__noreturn static void print_help_and_die(struct client_task *ct)
+{
+	struct ggo_help h = DEFINE_GGO_HELP(client);
+	bool d = ct->conf.detailed_help_given;
+
+	ggo_print_help(&h, d? GPH_STANDARD_FLAGS_DETAILED : GPH_STANDARD_FLAGS);
+	exit(0);
+}
+
+/**
+ * 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)
+{
+	char *home = para_homedir();
+	int ret;
+	struct client_task *ct = para_calloc(sizeof(struct client_task));
+
+	*ct_ptr = ct;
+	ct->scc.fd = -1;
+	ret = -E_CLIENT_SYNTAX;
+	if (client_cmdline_parser(argc, argv, &ct->conf))
+		goto out;
+	version_handle_flag("client", ct->conf.version_given);
+	if (ct->conf.help_given || ct->conf.detailed_help_given)
+		print_help_and_die(ct);
+
+	ct->config_file = ct->conf.config_file_given?
+		para_strdup(ct->conf.config_file_arg) :
+		make_message("%s/.paraslash/client.conf", home);
+	ret = file_exists(ct->config_file);
+	if (!ret && ct->conf.config_file_given) {
+		ret = -E_NO_CONFIG;
+		goto out;
+	}
+	if (ret) {
+		struct client_cmdline_parser_params params = {
+			.override = 0,
+			.initialize = 0,
+			.check_required = 0,
+			.check_ambiguity = 0,
+			.print_errors = 0
+		};
+		ret = -E_BAD_CONFIG;
+		if (client_cmdline_parser_config_file(ct->config_file,
+			&ct->conf, &params))
+			goto out;
+	}
+	ct->user = ct->conf.user_given?
+		para_strdup(ct->conf.user_arg) : para_logname();
+
+	if (ct->conf.key_file_given)
+		ct->key_file = para_strdup(ct->conf.key_file_arg);
+	else {
+		ct->key_file = make_message("%s/.paraslash/key.%s",
+			home, ct->user);
+		if (!file_exists(ct->key_file)) {
+			free(ct->key_file);
+			ct->key_file = make_message("%s/.ssh/id_rsa", home);
+		}
+	}
+
+	if (loglevel)
+		*loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
+	PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
+	PARA_INFO_LOG("config_file: %s\n", ct->config_file);
+	PARA_INFO_LOG("key_file: %s\n", ct->key_file);
+	ret = ct->conf.inputs_num;
+out:
+	free(home);
+	if (ret < 0) {
+		PARA_ERROR_LOG("%s\n", para_strerror(-ret));
+		client_close(ct);
+		*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;
 }