eb9f9e1fcda2a49ba960582ba67be9c882897a20
[paraslash.git] / client_common.c
1 /*
2 * Copyright (C) 1997-2011 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 "string.h"
21 #include "client.cmdline.h"
22 #include "client.h"
23 #include "buffer_tree.h"
24 #include "version.h"
25
26 /** The size of the receiving buffer. */
27 #define CLIENT_BUFSIZE 4000
28
29 /**
30 * Close the connection to para_server and free all resources.
31 *
32 * \param ct Pointer to the client data.
33 *
34 * \sa client_open.
35 */
36 void client_close(struct client_task *ct)
37 {
38 if (!ct)
39 return;
40 if (ct->scc.fd >= 0)
41 close(ct->scc.fd);
42 sc_free(ct->scc.recv);
43 sc_free(ct->scc.send);
44 free(ct->user);
45 free(ct->config_file);
46 free(ct->key_file);
47 btr_free_node(ct->btrn);
48 client_cmdline_parser_free(&ct->conf);
49 free(ct);
50 }
51
52 /**
53 * The preselect hook for server commands.
54 *
55 * \param s Pointer to the scheduler.
56 * \param t Pointer to the task struct for this command.
57 *
58 * The task pointer must contain a pointer to the initialized client data
59 * structure as it is returned by client_open().
60 *
61 * This function checks the state of the connection and adds the file descriptor
62 * of the connection to the read or write fd set of \a s accordingly.
63 *
64 * \sa register_task() client_open(), struct sched, struct task.
65 */
66 static void client_pre_select(struct sched *s, struct task *t)
67 {
68 int ret;
69 struct client_task *ct = container_of(t, struct client_task, task);
70 struct btr_node *btrn = ct->btrn;
71
72 if (ct->scc.fd < 0)
73 return;
74 switch (ct->status) {
75 case CL_CONNECTED:
76 case CL_SENT_AUTH:
77 case CL_SENT_CH_RESPONSE:
78 case CL_SENT_COMMAND:
79 para_fd_set(ct->scc.fd, &s->rfds, &s->max_fileno);
80 return;
81
82 case CL_RECEIVED_WELCOME:
83 case CL_RECEIVED_PROCEED:
84 para_fd_set(ct->scc.fd, &s->wfds, &s->max_fileno);
85 return;
86
87 case CL_RECEIVING:
88 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
89 if (ret != 0) {
90 if (ret < 0)
91 sched_min_delay(s);
92 else
93 para_fd_set(ct->scc.fd, &s->rfds,
94 &s->max_fileno);
95 }
96 return;
97 case CL_SENDING:
98 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
99 if (ret != 0) {
100 if (ret < 0)
101 sched_min_delay(s);
102 else
103 para_fd_set(ct->scc.fd, &s->wfds,
104 &s->max_fileno);
105 }
106 return;
107 }
108 }
109
110 static int client_recv_buffer(struct client_task *ct, fd_set *rfds,
111 char *buf, size_t sz, size_t *n)
112 {
113 int ret;
114
115 if (ct->status < CL_SENT_CH_RESPONSE)
116 return read_nonblock(ct->scc.fd, buf, sz, rfds, n);
117
118 *n = 0;
119 ret = sc_recv_buffer(&ct->scc, buf, sz);
120 /*
121 * sc_recv_buffer is used with blocking fds elsewhere, so it
122 * does not use the nonblock-API. Therefore we need to
123 * check for EOF and EAGAIN.
124 */
125 if (ret == 0)
126 return -E_SERVER_EOF;
127 if (ret == -ERRNO_TO_PARA_ERROR(EAGAIN))
128 return 0;
129 if (ret < 0)
130 return ret;
131 *n = ret;
132 return 0;
133 }
134
135 /**
136 * The post select hook for client commands.
137 *
138 * \param s Pointer to the scheduler.
139 * \param t Pointer to the task struct for this command.
140 *
141 * Depending on the current state of the connection and the status of the read
142 * and write fd sets of \a s, this function performs the necessary steps to
143 * authenticate the connection, to send the command given by \a t->private_data
144 * and to receive para_server's output, if any.
145 *
146 * \sa struct sched, struct task.
147 */
148 static void client_post_select(struct sched *s, struct task *t)
149 {
150 struct client_task *ct = container_of(t, struct client_task, task);
151 struct btr_node *btrn = ct->btrn;
152 int ret = 0;
153 size_t n;
154 char buf[CLIENT_BUFSIZE];
155
156 t->error = 0;
157 if (ct->scc.fd < 0)
158 return;
159 switch (ct->status) {
160 case CL_CONNECTED: /* receive welcome message */
161 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
162 if (ret < 0 || n == 0)
163 goto out;
164 ct->status = CL_RECEIVED_WELCOME;
165 return;
166 case CL_RECEIVED_WELCOME: /* send auth command */
167 sprintf(buf, AUTH_REQUEST_MSG "%s", ct->user);
168 PARA_INFO_LOG("--> %s\n", buf);
169 if (!FD_ISSET(ct->scc.fd, &s->wfds))
170 return;
171 ret = send_buffer(ct->scc.fd, buf);
172 if (ret < 0)
173 goto out;
174 ct->status = CL_SENT_AUTH;
175 return;
176 case CL_SENT_AUTH:
177 /*
178 * Receive challenge and session keys, decrypt the challenge and
179 * send back the hash of the decrypted challenge.
180 */
181 {
182 /* decrypted challenge/session key buffer */
183 unsigned char crypt_buf[1024];
184 /* the SHA1 of the decrypted challenge */
185 unsigned char challenge_hash[HASH_SIZE];
186
187 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
188 if (ret < 0 || n == 0)
189 goto out;
190 PARA_INFO_LOG("<-- [challenge] (%zu bytes)\n", n);
191 ret = priv_decrypt(ct->key_file, crypt_buf,
192 (unsigned char *)buf, n);
193 if (ret < 0)
194 goto out;
195 hash_function((char *)crypt_buf, CHALLENGE_SIZE, challenge_hash);
196 ct->scc.send = sc_new(crypt_buf + CHALLENGE_SIZE, SESSION_KEY_LEN);
197 ct->scc.recv = sc_new(crypt_buf + CHALLENGE_SIZE + SESSION_KEY_LEN,
198 SESSION_KEY_LEN);
199 hash_to_asc(challenge_hash, buf);
200 PARA_INFO_LOG("--> %s\n", buf);
201 ret = send_bin_buffer(ct->scc.fd, (char *)challenge_hash,
202 HASH_SIZE);
203 if (ret < 0)
204 goto out;
205 ct->status = CL_SENT_CH_RESPONSE;
206 return;
207 }
208 case CL_SENT_CH_RESPONSE: /* read server response */
209 {
210 ret = client_recv_buffer(ct, &s->rfds, buf, sizeof(buf), &n);
211 if (ret < 0 || n == 0)
212 goto out;
213 /* check if server has sent "Proceed" message */
214 ret = -E_CLIENT_AUTH;
215 if (n < PROCEED_MSG_LEN)
216 goto out;
217 if (!strstr(buf, PROCEED_MSG))
218 goto out;
219 ct->status = CL_RECEIVED_PROCEED;
220 return;
221 }
222 case CL_RECEIVED_PROCEED: /* concat args and send command */
223 {
224 int i;
225 char *command = NULL;
226 if (!FD_ISSET(ct->scc.fd, &s->wfds))
227 return;
228 for (i = 0; i < ct->conf.inputs_num; i++) {
229 char *tmp = command;
230 command = make_message("%s\n%s", command?
231 command : "", ct->conf.inputs[i]);
232 free(tmp);
233 }
234 command = para_strcat(command, EOC_MSG "\n");
235 PARA_DEBUG_LOG("--> %s\n", command);
236 ret = sc_send_buffer(&ct->scc, command);
237 free(command);
238 if (ret < 0)
239 goto out;
240 ct->status = CL_SENT_COMMAND;
241 return;
242 }
243 case CL_SENT_COMMAND:
244 {
245 char *buf2;
246 /* can not use "buf" here because we need a malloced buffer */
247 buf2 = para_malloc(CLIENT_BUFSIZE);
248 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
249 if (n > 0) {
250 if (strstr(buf2, AWAITING_DATA_MSG)) {
251 free(buf2);
252 ct->status = CL_SENDING;
253 return;
254 }
255 ct->status = CL_RECEIVING;
256 btr_add_output(buf2, n, btrn);
257 } else
258 free(buf2);
259 goto out;
260 }
261 case CL_SENDING:
262 {
263 char *buf2;
264 size_t sz;
265 ret = btr_node_status(btrn, 0, BTR_NT_LEAF);
266 if (ret < 0)
267 goto out;
268 if (ret == 0)
269 return;
270 if (!FD_ISSET(ct->scc.fd, &s->wfds))
271 return;
272 sz = btr_next_buffer(btrn, &buf2);
273 ret = sc_send_bin_buffer(&ct->scc, buf2, sz);
274 if (ret < 0)
275 goto out;
276 btr_consume(btrn, sz);
277 return;
278 }
279 case CL_RECEIVING:
280 {
281 char *buf2;
282 ret = btr_node_status(btrn, 0, BTR_NT_ROOT);
283 if (ret < 0)
284 goto out;
285 if (ret == 0)
286 return;
287 /*
288 * The FD_ISSET() is not strictly necessary, but is allows us
289 * to skip the malloc below if there is nothing to read anyway.
290 */
291 if (!FD_ISSET(ct->scc.fd, &s->rfds))
292 return;
293 buf2 = para_malloc(CLIENT_BUFSIZE);
294 ret = client_recv_buffer(ct, &s->rfds, buf2, CLIENT_BUFSIZE, &n);
295 if (n > 0) {
296 buf2 = para_realloc(buf2, n);
297 btr_add_output(buf2, n, btrn);
298 } else
299 free(buf2);
300 goto out;
301 }
302 }
303 out:
304 t->error = ret;
305 if (ret < 0) {
306 if (ret != -E_SERVER_EOF && ret != -E_BTR_EOF)
307 PARA_ERROR_LOG("%s\n", para_strerror(-t->error));
308 btr_remove_node(btrn);
309 }
310 }
311
312 /* connect to para_server and register the client task */
313 static int client_connect(struct client_task *ct)
314 {
315 int ret;
316
317 ct->scc.fd = -1;
318 ret = para_connect_simple(IPPROTO_TCP, ct->conf.hostname_arg,
319 ct->conf.server_port_arg);
320 if (ret < 0)
321 return ret;
322 ct->scc.fd = ret;
323 ct->status = CL_CONNECTED;
324 ret = mark_fd_nonblocking(ct->scc.fd);
325 if (ret < 0)
326 goto err_out;
327 ct->task.pre_select = client_pre_select;
328 ct->task.post_select = client_post_select;
329 sprintf(ct->task.status, "client");
330 register_task(&ct->task);
331 return 1;
332 err_out:
333 close(ct->scc.fd);
334 ct->scc.fd = -1;
335 return ret;
336 }
337
338 /**
339 * Open connection to para_server.
340 *
341 * \param argc Usual argument count.
342 * \param argv Usual argument vector.
343 * \param ct_ptr Points to dynamically allocated and initialized client task
344 * struct upon successful return.
345 * \param loglevel If not \p NULL, the number of the loglevel is stored here.
346 * \param parent Add the new buffer tree node as a child of this node.
347 * \param child Add the new buffer tree node as a parent of this node.
348 *
349 * Check the command line options given by \a argc and argv, set default values
350 * for user name and rsa key file, read further option from the config file.
351 * Finally, establish a connection to para_server.
352 *
353 * \return Standard.
354 */
355 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
356 int *loglevel, struct btr_node *parent, struct btr_node *child)
357 {
358 char *home = para_homedir();
359 int ret;
360 struct client_task *ct = para_calloc(sizeof(struct client_task));
361
362 ct->btrn = btr_new_node(&(struct btr_node_description)
363 EMBRACE(.name = "client", .parent = parent, .child = child));
364 *ct_ptr = ct;
365 ct->scc.fd = -1;
366 ret = -E_CLIENT_SYNTAX;
367 if (client_cmdline_parser(argc, argv, &ct->conf))
368 goto out;
369 HANDLE_VERSION_FLAG("client", ct->conf);
370 ret = -E_CLIENT_SYNTAX;
371 if (!ct->conf.inputs_num)
372 goto out;
373
374 ct->config_file = ct->conf.config_file_given?
375 para_strdup(ct->conf.config_file_arg) :
376 make_message("%s/.paraslash/client.conf", home);
377 ret = file_exists(ct->config_file);
378 if (!ret && ct->conf.config_file_given) {
379 ret = -E_NO_CONFIG;
380 goto out;
381 }
382 if (ret) {
383 struct client_cmdline_parser_params params = {
384 .override = 0,
385 .initialize = 0,
386 .check_required = 0,
387 .check_ambiguity = 0,
388 .print_errors = 0
389 };
390 ret = -E_BAD_CONFIG;
391 if (client_cmdline_parser_config_file(ct->config_file,
392 &ct->conf, &params))
393 goto out;
394 }
395 ct->user = ct->conf.user_given?
396 para_strdup(ct->conf.user_arg) : para_logname();
397
398 if (ct->conf.key_file_given)
399 ct->key_file = para_strdup(ct->conf.key_file_arg);
400 else {
401 ct->key_file = make_message("%s/.paraslash/key.%s",
402 home, ct->user);
403 if (!file_exists(ct->key_file)) {
404 free(ct->key_file);
405 ct->key_file = make_message("%s/.ssh/id_rsa", home);
406 }
407 }
408
409 if (loglevel)
410 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
411 PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
412 PARA_INFO_LOG("config_file: %s\n", ct->config_file);
413 PARA_INFO_LOG("key_file: %s\n", ct->key_file);
414 PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
415 ct->conf.server_port_arg);
416 ret = client_connect(ct);
417 out:
418 free(home);
419 if (ret < 0) {
420 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
421 btr_remove_node(ct->btrn);
422 client_close(ct);
423 *ct_ptr = NULL;
424 }
425 return ret;
426 }