Add sideband implementation.
[paraslash.git] / client_common.c
1 /*
2 * Copyright (C) 1997-2012 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file client_common.c Common functions of para_client and para_audiod. */
8
9 #include <regex.h>
10 #include <sys/types.h>
11
12 #include "para.h"
13 #include "error.h"
14 #include "list.h"
15 #include "sched.h"
16 #include "client.cmdline.h"
17 #include "crypt.h"
18 #include "net.h"
19 #include "fd.h"
20 #include "sideband.h"
21 #include "string.h"
22 #include "client.cmdline.h"
23 #include "client.h"
24 #include "buffer_tree.h"
25 #include "version.h"
26
27 /** The size of the receiving buffer. */
28 #define CLIENT_BUFSIZE 4000
29
30 /**
31 * Close the connection to para_server and deallocate per-command ressources.
32 *
33 * \param ct The client task.
34 *
35 * This frees all ressources of the current command but keeps the configuration
36 * in \p ct->conf.
37 *
38 * \sa \ref client_close().
39 */
40 void client_disconnect(struct client_task *ct)
41 {
42 if (!ct)
43 return;
44 if (ct->scc.fd >= 0)
45 close(ct->scc.fd);
46 free_argv(ct->features);
47 sc_free(ct->scc.recv);
48 ct->scc.recv = NULL;
49 sc_free(ct->scc.send);
50 ct->scc.send = NULL;
51 btr_free_node(ct->btrn);
52 ct->btrn = NULL;
53 }
54
55 /**
56 * Close the connection to para_server and free all resources.
57 *
58 * \param ct Pointer to the client data.
59 *
60 * \sa \ref client_open(), \ref client_disconnect().
61 */
62 void client_close(struct client_task *ct)
63 {
64 if (!ct)
65 return;
66 client_disconnect(ct);
67 free(ct->user);
68 free(ct->config_file);
69 free(ct->key_file);
70 client_cmdline_parser_free(&ct->conf);
71 free(ct);
72 }
73
74 /**
75 * The preselect hook for server commands.
76 *
77 * \param s Pointer to the scheduler.
78 * \param t Pointer to the task struct for this command.
79 *
80 * The task pointer must contain a pointer to the initialized client data
81 * structure as it is returned by client_open().
82 *
83 * This function checks the state of the connection and adds the file descriptor
84 * of the connection to the read or write fd set of \a s accordingly.
85 *
86 * \sa register_task() client_open(), struct sched, struct task.
87 */
88 static void client_pre_select(struct sched *s, struct task *t)
89 {
90 int ret;
91 struct client_task *ct = container_of(t, struct client_task, task);
92 struct btr_node *btrn = ct->btrn;
93
94 if (ct->scc.fd < 0)
95 return;
96 switch (ct->status) {
97 case CL_CONNECTED:
98 case CL_SENT_AUTH:
99 case CL_SENT_CH_RESPONSE:
100 case CL_SENT_COMMAND:
101 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
102 return;
103
104 case CL_RECEIVED_WELCOME:
105 case CL_RECEIVED_PROCEED:
106 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
107 return;
108
109 case CL_RECEIVING:
110 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
111 if (ret != 0) {
112 if (ret < 0)
113 sched_min_delay(s);
114 else
115 para_fd_set(ct->scc.fd, &s->rfds,
116 &s->max_fileno);
117 }
118 return;
119 case CL_SENDING:
120 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
121 if (ret != 0) {
122 if (ret < 0)
123 sched_min_delay(s);
124 else
125 para_fd_set(ct->scc.fd, &s->wfds,
126 &s->max_fileno);
127 }
128 return;
129 }
130 }
131
132 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
133 char *buf, size_t sz, size_t *n)
134 {
135 int ret;
136
137 if (ct->status < CL_SENT_CH_RESPONSE)
138 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
139
140 *n = 0;
141 ret = sc_recv_buffer(&ct->scc, buf, sz);
142 /*
143 * sc_recv_buffer is used with blocking fds elsewhere, so it
144 * does not use the nonblock-API. Therefore we need to
145 * check for EOF and EAGAIN.
146 */
147 if (ret == 0)
148 return -E_SERVER_EOF;
149 if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
150 return 0;
151 if (ret < 0)
152 return ret;
153 *n = ret;
154 return 0;
155 }
156
157 static int send_sb(struct client_task *ct, void *buf, size_t numbytes,
158 enum sb_designator band, bool dont_free)
159 {
160 int ret, fd = ct->scc.fd;
161 struct iovec iov[2];
162
163 if (!ct->sbc) {
164 struct sb_buffer sbb;
165 sb_transformation trafo = ct->status < CL_RECEIVED_PROCEED?
166 NULL : sc_trafo;
167 sbb = (typeof(sbb))SBB_INIT(band, buf, numbytes);
168 ct->sbc = sb_new_send(&sbb, dont_free, trafo, ct->scc.send);
169 }
170 ret = sb_get_send_buffers(ct->sbc, iov);
171 ret = xwritev(fd, iov, ret);
172 if (ret < 0) {
173 sb_free(ct->sbc);
174 ct->sbc = NULL;
175 return ret;
176 }
177 if (sb_sent(ct->sbc, ret)) {
178 ct->sbc = NULL;
179 return 1;
180 }
181 return 0;
182 }
183
184 static int recv_sb(struct client_task *ct, fd_set *rfds,
185 struct sb_buffer *result)
186 {
187 int ret;
188 size_t n;
189 sb_transformation trafo;
190 void *trafo_context;
191 struct iovec iov;
192
193 if (!FD_ISSET(ct->scc.fd, rfds))
194 return 0;
195 if (ct->status < CL_SENT_CH_RESPONSE)
196 trafo = trafo_context = NULL;
197 else {
198 trafo = sc_trafo;
199 trafo_context = ct->scc.recv;
200 }
201 if (!ct->sbc)
202 ct->sbc = sb_new_recv(0, trafo, trafo_context);
203 again:
204 sb_get_recv_buffer(ct->sbc, &iov);
205 ret = read_nonblock(ct->scc.fd, iov.iov_base, iov.iov_len, rfds, &n);
206 if (ret < 0) {
207 sb_free(ct->sbc);
208 ct->sbc = NULL;
209 return ret;
210 }
211 if (n == 0)
212 return 0;
213 if (!sb_received(ct->sbc, n, result))
214 goto again;
215 ct->sbc = NULL;
216 return 1;
217 }
218
219
220 static char **parse_features(char *buf)
221 {
222 int i;
223 const char id[] = "\nFeatures: ";
224 char *p, *q, **features;
225
226 p = strstr(buf, id);
227 if (!p)
228 return NULL;
229 p += strlen(id);
230 q = strchr(p, '\n');
231 if (!q)
232 return NULL;
233 *q = '\0';
234 create_argv(p, ",", &features);
235 for (i = 0; features[i]; i++)
236 PARA_INFO_LOG("server feature: %s\n", features[i]);
237 return features;
238 }
239
240 static bool has_feature(const char *feature, struct client_task *ct)
241 {
242 return find_arg(feature, ct->features) >= 0? true : false;
243 }
244
245 /**
246 * The post select hook for client commands.
247 *
248 * \param s Pointer to the scheduler.
249 * \param t Pointer to the task struct for this command.
250 *
251 * Depending on the current state of the connection and the status of the read
252 * and write fd sets of \a s, this function performs the necessary steps to
253 * authenticate the connection, to send the command given by \a t->private_data
254 * and to receive para_server's output, if any.
255 *
256 * \sa struct sched, struct task.
257 */
258 static void client_post_select(struct sched *s, struct task *t)
259 {
260 struct client_task *ct = container_of(t, struct client_task, task);
261 struct btr_node *btrn = ct->btrn;
262 int ret = 0;
263 size_t n;
264 char buf[CLIENT_BUFSIZE];
265
266 t->error = 0;
267 if (ct->scc.fd < 0)
268 return;
269 switch (ct->status) {
270 case CL_CONNECTED: /* receive welcome message */
271 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
272 if (ret < 0 || n == 0)
273 goto out;
274 ct->features = parse_features(buf);
275 ct->status = CL_RECEIVED_WELCOME;
276 return;
277 case CL_RECEIVED_WELCOME: /* send auth command */
278 if (!FD_ISSET(ct->scc.fd, &s->wfds))
279 return;
280 if (has_feature("sideband", ct)) {
281 ct->use_sideband = true;
282 sprintf(buf, AUTH_REQUEST_MSG "%s sideband", ct->user);
283 } else
284 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
285 PARA_INFO_LOG("--> %s\n", buf);
286 ret = write_buffer(ct->scc.fd, buf);
287 if (ret < 0)
288 goto out;
289 ct->status = CL_SENT_AUTH;
290 return;
291 case CL_SENT_AUTH:
292 /*
293 * Receive challenge and session keys, decrypt the challenge and
294 * send back the hash of the decrypted challenge.
295 */
296 {
297 /* decrypted challenge/session key buffer */
298 unsigned char crypt_buf[1024];
299 /* the SHA1 of the decrypted challenge */
300 unsigned char challenge_hash[HASH_SIZE];
301
302 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
303 if (ret < 0 || n == 0)
304 goto out;
305 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
306 ret = priv_decrypt(ct->key_file, crypt_buf,
307 (unsigned char *)buf, n);
308 if (ret < 0)
309 goto out;
310 hash_function((char *)crypt_buf, CHALLENGE_SIZE, challenge_hash);
311 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
312 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
313 SESSION_KEY_LEN);
314 hash_to_asc(challenge_hash, buf);
315 PARA_INFO_LOG("--> %s\n", buf);
316 ret = write_all(ct->scc.fd, (char *)challenge_hash, HASH_SIZE);
317 if (ret < 0)
318 goto out;
319 ct->status = CL_SENT_CH_RESPONSE;
320 return;
321 }
322 case CL_SENT_CH_RESPONSE: /* read server response */
323 {
324 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
325 if (ret < 0 || n == 0)
326 goto out;
327 /* check if server has sent "Proceed" message */
328 ret = -E_CLIENT_AUTH;
329 if (n < PROCEED_MSG_LEN)
330 goto out;
331 if (!strstr(buf, PROCEED_MSG))
332 goto out;
333 ct->status = CL_RECEIVED_PROCEED;
334 return;
335 }
336 case CL_RECEIVED_PROCEED: /* concat args and send command */
337 {
338 int i;
339 char *command = NULL;
340 if (!FD_ISSET(ct->scc.fd, &s->wfds))
341 return;
342 for (i = 0; i < ct->conf.inputs_num; i++) {
343 char *tmp = command;
344 command = make_message("%s\n%s", command?
345 command : "", ct->conf.inputs[i]);
346 free(tmp);
347 }
348 command = para_strcat(command, EOC_MSG "\n");
349 PARA_DEBUG_LOG("--> %s\n", command);
350 ret = sc_send_buffer(&ct->scc, command);
351 free(command);
352 if (ret < 0)
353 goto out;
354 ct->status = CL_SENT_COMMAND;
355 return;
356 }
357 case CL_SENT_COMMAND:
358 {
359 char *buf2;
360 /* can not use "buf" here because we need a malloced buffer */
361 buf2 = para_malloc(CLIENT_BUFSIZE);
362 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
363 if (n > 0) {
364 if (strstr(buf2, AWAITING_DATA_MSG)) {
365 free(buf2);
366 ct->status = CL_SENDING;
367 return;
368 }
369 ct->status = CL_RECEIVING;
370 btr_add_output(buf2, n, btrn);
371 } else
372 free(buf2);
373 goto out;
374 }
375 case CL_SENDING:
376 {
377 char *buf2;
378 size_t sz;
379 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
380 if (ret < 0)
381 goto out;
382 if (ret == 0)
383 return;
384 if (!FD_ISSET(ct->scc.fd, &s->wfds))
385 return;
386 sz = btr_next_buffer(btrn, &buf2);
387 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
388 if (ret < 0)
389 goto out;
390 btr_consume(btrn, sz);
391 return;
392 }
393 case CL_RECEIVING:
394 {
395 char *buf2;
396 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
397 if (ret < 0)
398 goto out;
399 if (ret == 0)
400 return;
401 /*
402 * The FD_ISSET() is not strictly necessary, but is allows us
403 * to skip the malloc below if there is nothing to read anyway.
404 */
405 if (!FD_ISSET(ct->scc.fd, &s->rfds))
406 return;
407 buf2 = para_malloc(CLIENT_BUFSIZE);
408 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
409 if (n > 0) {
410 buf2 = para_realloc(buf2, n);
411 btr_add_output(buf2, n, btrn);
412 } else
413 free(buf2);
414 goto out;
415 }
416 }
417 out:
418 t->error = ret;
419 if (ret < 0) {
420 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
421 PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
422 btr_remove_node(btrn);
423 }
424 }
425
426 /**
427 * Connect to para_server and register the client task.
428 *
429 * \param ct The initialized client task structure.
430 * \param s The scheduler instance to register the client task to.
431 * \param parent The parent node of the client btr node.
432 * \param child The child node of the client node.
433 *
434 * The client task structure given by \a ct must be allocated and initialized
435 * by \ref client_parse_config() before this function is called.
436 *
437 * \return Standard.
438 */
439 int client_connect(struct client_task *ct, struct sched *s,
440 struct btr_node *parent, struct btr_node *child)
441 {
442 int ret;
443
444 PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
445 ct->conf.server_port_arg);
446 ct->scc.fd = -1;
447 ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
448 ct->conf.server_port_arg);
449 if (ret < 0)
450 return ret;
451 ct->scc.fd = ret;
452 ret = mark_fd_nonblocking(ct->scc.fd);
453 if (ret < 0)
454 goto err_out;
455 ct->status = CL_CONNECTED;
456 ct->btrn = btr_new_node(&(struct btr_node_description)
457 EMBRACE(.name = "client", .parent = parent, .child = child));
458 ct->task.pre_select = client_pre_select;
459 ct->task.post_select = client_post_select;
460 ct->task.error = 0;
461 sprintf(ct->task.status, "client");
462 register_task(s, &ct->task);
463 return 1;
464 err_out:
465 close(ct->scc.fd);
466 ct->scc.fd = -1;
467 return ret;
468 }
469
470 /**
471 * Parse a client configuration.
472 *
473 * \param argc Usual argument count.
474 * \param argv Usual argument vector.
475 * \param ct_ptr Filled in by this function.
476 * \param loglevel If not \p NULL, the number of the loglevel is stored here.
477 *
478 * This checks the command line options given by \a argc and \a argv, sets
479 * default values for the user name and the name of the rsa key file and reads
480 * further options from the config file.
481 *
482 * Upon successful return, \a ct_ptr points to a dynamically allocated and
483 * initialized client task struct.
484 *
485 * \return The number of non-option arguments in \a argc/argv on success,
486 * negative on errors.
487 */
488 int client_parse_config(int argc, char *argv[], struct client_task **ct_ptr,
489 int *loglevel)
490 {
491 char *home = para_homedir();
492 int ret;
493 struct client_task *ct = para_calloc(sizeof(struct client_task));
494
495 *ct_ptr = ct;
496 ct->scc.fd = -1;
497 ret = -E_CLIENT_SYNTAX;
498 if (client_cmdline_parser(argc, argv, &ct->conf))
499 goto out;
500 HANDLE_VERSION_FLAG("client", ct->conf);
501
502 ct->config_file = ct->conf.config_file_given?
503 para_strdup(ct->conf.config_file_arg) :
504 make_message("%s/.paraslash/client.conf", home);
505 ret = file_exists(ct->config_file);
506 if (!ret && ct->conf.config_file_given) {
507 ret = -E_NO_CONFIG;
508 goto out;
509 }
510 if (ret) {
511 struct client_cmdline_parser_params params = {
512 .override = 0,
513 .initialize = 0,
514 .check_required = 0,
515 .check_ambiguity = 0,
516 .print_errors = 0
517 };
518 ret = -E_BAD_CONFIG;
519 if (client_cmdline_parser_config_file(ct->config_file,
520 &ct->conf, &params))
521 goto out;
522 }
523 ct->user = ct->conf.user_given?
524 para_strdup(ct->conf.user_arg) : para_logname();
525
526 if (ct->conf.key_file_given)
527 ct->key_file = para_strdup(ct->conf.key_file_arg);
528 else {
529 ct->key_file = make_message("%s/.paraslash/key.%s",
530 home, ct->user);
531 if (!file_exists(ct->key_file)) {
532 free(ct->key_file);
533 ct->key_file = make_message("%s/.ssh/id_rsa", home);
534 }
535 }
536
537 if (loglevel)
538 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
539 PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
540 PARA_INFO_LOG("config_file: %s\n", ct->config_file);
541 PARA_INFO_LOG("key_file: %s\n", ct->key_file);
542 ret = ct->conf.inputs_num;
543 out:
544 free(home);
545 if (ret < 0) {
546 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
547 client_close(ct);
548 *ct_ptr = NULL;
549 }
550 return ret;
551 }
552
553 /**
554 * Parse the client configuration and open a connection to para_server.
555 *
556 * \param argc See \ref client_parse_config.
557 * \param argv See \ref client_parse_config.
558 * \param ct_ptr See \ref client_parse_config.
559 * \param loglevel See \ref client_parse_config.
560 * \param parent See \ref client_connect().
561 * \param child See \ref client_connect().
562 * \param sched See \ref client_connect().
563 *
564 * This function combines client_parse_config() and client_connect(). It is
565 * considered a syntax error if no command was given, i.e. if the number
566 * of non-option arguments is zero.
567 *
568 * \return Standard.
569 */
570 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
571 int *loglevel, struct btr_node *parent, struct btr_node *child,
572 struct sched *sched)
573 {
574 int ret = client_parse_config(argc, argv, ct_ptr, loglevel);
575
576 if (ret < 0)
577 return ret;
578 if (ret == 0) {
579 ret = -E_CLIENT_SYNTAX;
580 goto fail;
581 }
582 ret = client_connect(*ct_ptr, sched, parent, child);
583 if (ret < 0)
584 goto fail;
585 return 1;
586 fail:
587 client_close(*ct_ptr);
588 *ct_ptr = NULL;
589 return ret;
590 }