1 /*
2 * SysDB - src/frontend/connection.c
3 * Copyright (C) 2013 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #include "sysdb.h"
29 #include "core/object.h"
30 #include "core/plugin.h"
31 #include "frontend/connection-private.h"
32 #include "frontend/parser.h"
33 #include "utils/error.h"
34 #include "utils/strbuf.h"
35 #include "utils/proto.h"
37 #include <assert.h>
38 #include <errno.h>
40 #include <arpa/inet.h>
41 #include <fcntl.h>
43 #include <stdlib.h>
44 #include <string.h>
46 #include <pthread.h>
48 /*
49 * private variables
50 */
52 static pthread_key_t conn_ctx_key;
53 static _Bool conn_ctx_key_initialized = 0;
55 /*
56 * private types
57 */
59 /* name of connection objects */
60 #define CONN_FD_PREFIX "conn#"
61 #define CONN_FD_PLACEHOLDER "XXXXXXX"
63 static int
64 connection_init(sdb_object_t *obj, va_list ap)
65 {
66 sdb_conn_t *conn;
67 int sock_fd;
68 int sock_fl;
70 assert(obj);
71 conn = CONN(obj);
73 sock_fd = va_arg(ap, int);
75 conn->buf = sdb_strbuf_create(/* size = */ 128);
76 if (! conn->buf) {
77 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
78 "for a new connection");
79 return -1;
80 }
81 conn->errbuf = sdb_strbuf_create(0);
82 if (! conn->errbuf) {
83 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
84 "for a new connection");
85 return -1;
86 }
88 conn->client_addr_len = sizeof(conn->client_addr);
89 conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
90 &conn->client_addr_len);
92 if (conn->fd < 0) {
93 char buf[1024];
94 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
95 "connection: %s", sdb_strerror(errno,
96 buf, sizeof(buf)));
97 return -1;
98 }
100 if (conn->client_addr.ss_family != AF_UNIX) {
101 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
102 "unexpected family type %d", conn->client_addr.ss_family);
103 return -1;
104 }
106 sock_fl = fcntl(conn->fd, F_GETFL);
107 if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
108 char buf[1024];
109 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
110 "to non-blocking mode: %s", conn->fd,
111 sdb_strerror(errno, buf, sizeof(buf)));
112 return -1;
113 }
115 sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
116 conn->fd);
118 conn->cmd = CONNECTION_IDLE;
119 conn->cmd_len = 0;
121 /* update the object name */
122 snprintf(obj->name + strlen(CONN_FD_PREFIX),
123 strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
124 return 0;
125 } /* connection_init */
127 static void
128 connection_destroy(sdb_object_t *obj)
129 {
130 sdb_conn_t *conn;
131 size_t len;
133 assert(obj);
134 conn = CONN(obj);
136 if (conn->buf) {
137 len = sdb_strbuf_len(conn->buf);
138 if (len)
139 sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
140 "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
141 }
143 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
144 if (conn->fd >= 0)
145 close(conn->fd);
146 conn->fd = -1;
148 if (conn->username)
149 free(conn->username);
150 conn->username = NULL;
152 sdb_strbuf_destroy(conn->buf);
153 conn->buf = NULL;
154 sdb_strbuf_destroy(conn->errbuf);
155 conn->errbuf = NULL;
156 } /* connection_destroy */
158 static sdb_type_t connection_type = {
159 /* size = */ sizeof(sdb_conn_t),
160 /* init = */ connection_init,
161 /* destroy = */ connection_destroy,
162 };
164 /*
165 * private helper functions
166 */
168 static void
169 sdb_conn_ctx_destructor(void *c)
170 {
171 sdb_object_t *conn = c;
173 if (! conn)
174 return;
175 sdb_object_deref(conn);
176 } /* sdb_conn_ctx_destructor */
178 static void
179 sdb_conn_ctx_init(void)
180 {
181 if (conn_ctx_key_initialized)
182 return;
184 pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
185 conn_ctx_key_initialized = 1;
186 } /* sdb_conn_ctx_init */
188 static void
189 sdb_conn_set_ctx(sdb_conn_t *conn)
190 {
191 sdb_conn_t *old;
193 sdb_conn_ctx_init();
195 old = pthread_getspecific(conn_ctx_key);
196 if (old)
197 sdb_object_deref(SDB_OBJ(old));
198 if (conn)
199 sdb_object_ref(SDB_OBJ(conn));
200 pthread_setspecific(conn_ctx_key, conn);
201 } /* sdb_conn_set_ctx */
203 static sdb_conn_t *
204 sdb_conn_get_ctx(void)
205 {
206 if (! conn_ctx_key_initialized)
207 return NULL;
208 return pthread_getspecific(conn_ctx_key);
209 } /* sdb_conn_get_ctx */
211 /*
212 * connection handler functions
213 */
215 /*
216 * connection_log:
217 * Send a log message originating from the current thread to the client.
218 */
219 static int
220 connection_log(int prio, const char *msg,
221 sdb_object_t __attribute__((unused)) *user_data)
222 {
223 sdb_conn_t *conn;
225 conn = sdb_conn_get_ctx();
226 /* no connection associated to this thread
227 * or user not authenticated yet => don't leak any information */
228 if ((! conn) || (! conn->username))
229 return 0;
231 /* XXX: make the log-level configurable by the client at runtime */
232 if (prio >= SDB_LOG_DEBUG)
233 return 0;
235 /* TODO: Use CONNECTION_LOG_<prio>? */
236 if (sdb_connection_send(conn, CONNECTION_LOG,
237 (uint32_t)strlen(msg), msg) < 0)
238 return -1;
239 return 0;
240 } /* connection_log */
242 static uint32_t
243 connection_get_int32(sdb_conn_t *conn, size_t offset)
244 {
245 const char *data;
246 uint32_t n;
248 assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
250 data = sdb_strbuf_string(conn->buf);
251 memcpy(&n, data + offset, sizeof(n));
252 n = ntohl(n);
253 return n;
254 } /* connection_get_int32 */
256 static int
257 command_handle(sdb_conn_t *conn)
258 {
259 int status = -1;
261 assert(conn && (conn->cmd != CONNECTION_IDLE));
263 sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
264 conn->cmd, conn->cmd_len);
266 if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
267 const char *errmsg = "Authentication required";
268 sdb_connection_send(conn, CONNECTION_ERROR,
269 (uint32_t)strlen(errmsg), errmsg);
270 return -1;
271 }
273 /* reset */
274 sdb_strbuf_sprintf(conn->errbuf, "");
276 switch (conn->cmd) {
277 case CONNECTION_PING:
278 status = sdb_connection_ping(conn);
279 break;
280 case CONNECTION_STARTUP:
281 status = sdb_fe_session_start(conn);
282 break;
284 case CONNECTION_QUERY:
285 {
286 sdb_llist_t *parsetree;
287 sdb_conn_node_t *node = NULL;
289 parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
290 (int)conn->cmd_len);
291 if (! parsetree) {
292 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
293 sdb_strbuf_string(conn->buf));
294 status = -1;
295 break;
296 }
298 switch (sdb_llist_len(parsetree)) {
299 case 0:
300 /* skipping empty command */
301 break;
302 case 1:
303 node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
304 break;
306 default:
307 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
308 "in multi-statement query '%s'",
309 sdb_llist_len(parsetree) - 1,
310 sdb_llist_len(parsetree) == 2 ? "" : "s",
311 sdb_strbuf_string(conn->buf));
312 node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
313 }
315 if (node) {
316 status = sdb_fe_exec(conn, node);
317 sdb_object_deref(SDB_OBJ(node));
318 }
320 sdb_llist_destroy(parsetree);
321 break;
322 }
324 case CONNECTION_FETCH:
325 status = sdb_fe_fetch(conn, sdb_strbuf_string(conn->buf));
326 break;
327 case CONNECTION_LIST:
328 status = sdb_fe_list(conn);
329 break;
330 case CONNECTION_LOOKUP:
331 {
332 sdb_store_matcher_t *m;
334 m = sdb_fe_parse_matcher(sdb_strbuf_string(conn->buf),
335 (int)conn->cmd_len);
336 if (! m) {
337 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse expression '%s'",
338 sdb_strbuf_string(conn->buf));
339 status = -1;
340 break;
341 }
343 status = sdb_fe_lookup(conn, m);
344 sdb_object_deref(SDB_OBJ(m));
345 break;
346 }
348 default:
349 {
350 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
351 conn->cmd);
352 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
353 status = -1;
354 break;
355 }
356 }
358 if (status)
359 sdb_connection_send(conn, CONNECTION_ERROR,
360 (uint32_t)sdb_strbuf_len(conn->errbuf),
361 sdb_strbuf_string(conn->errbuf));
363 /* remove the command from the buffer */
364 if (conn->cmd_len)
365 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
366 conn->cmd = CONNECTION_IDLE;
367 conn->cmd_len = 0;
368 return status;
369 } /* command_handle */
371 /* initialize the connection state information */
372 static int
373 command_init(sdb_conn_t *conn)
374 {
375 size_t len;
377 assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
379 conn->cmd = connection_get_int32(conn, 0);
380 conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
382 len = 2 * sizeof(uint32_t);
383 if (conn->cmd == CONNECTION_IDLE)
384 len += conn->cmd_len;
385 sdb_strbuf_skip(conn->buf, 0, len);
386 return 0;
387 } /* command_init */
389 /* returns negative value on error, 0 on EOF, number of octets else */
390 static ssize_t
391 connection_read(sdb_conn_t *conn)
392 {
393 ssize_t n = 0;
395 if ((! conn) || (conn->fd < 0))
396 return -1;
398 while (42) {
399 ssize_t status;
401 errno = 0;
402 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
403 if (status < 0) {
404 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
405 break;
407 close(conn->fd);
408 conn->fd = -1;
409 return (int)status;
410 }
411 else if (! status) /* EOF */
412 break;
414 n += status;
415 }
417 return n;
418 } /* connection_read */
420 /*
421 * public API
422 */
424 int
425 sdb_connection_enable_logging(void)
426 {
427 return sdb_plugin_register_log("connection-logger", connection_log,
428 /* user_data = */ NULL);
429 } /* sdb_connection_enable_logging */
431 sdb_conn_t *
432 sdb_connection_accept(int fd)
433 {
434 if (fd < 0)
435 return NULL;
437 /* the placeholder will be replaced with the accepted file
438 * descriptor when initializing the object */
439 return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
440 connection_type, fd));
441 } /* sdb_connection_create */
443 void
444 sdb_connection_close(sdb_conn_t *conn)
445 {
446 if (! conn)
447 return;
449 /* close the connection even if someone else still references it */
450 if (conn->fd >= 0)
451 close(conn->fd);
452 conn->fd = -1;
454 sdb_object_deref(SDB_OBJ(conn));
455 } /* sdb_connection_close */
457 ssize_t
458 sdb_connection_read(sdb_conn_t *conn)
459 {
460 ssize_t n = 0;
462 sdb_conn_set_ctx(conn);
464 while (42) {
465 ssize_t status = connection_read(conn);
467 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
468 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
469 command_init(conn);
470 if ((conn->cmd != CONNECTION_IDLE)
471 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
472 command_handle(conn);
474 if (status <= 0)
475 break;
477 n += status;
478 }
480 sdb_conn_set_ctx(NULL);
481 return n;
482 } /* sdb_connection_read */
484 ssize_t
485 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
486 uint32_t msg_len, const char *msg)
487 {
488 ssize_t status;
490 if ((! conn) || (conn->fd < 0))
491 return -1;
493 status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
494 if (status < 0) {
495 char errbuf[1024];
497 /* tell other code that there was a problem and, more importantly,
498 * make sure we don't try to send further logs to the connection */
499 close(conn->fd);
500 conn->fd = -1;
502 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
503 "(code: %u, len: %u) to client: %s", code, msg_len,
504 sdb_strerror(errno, errbuf, sizeof(errbuf)));
505 }
506 return status;
507 } /* sdb_connection_send */
509 int
510 sdb_connection_ping(sdb_conn_t *conn)
511 {
512 if ((! conn) || (conn->cmd != CONNECTION_PING))
513 return -1;
515 /* we're alive */
516 sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
517 return 0;
518 } /* sdb_connection_ping */
520 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */