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