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 "utils/error.h"
33 #include "utils/strbuf.h"
34 #include "utils/proto.h"
36 #include <assert.h>
37 #include <errno.h>
39 #include <arpa/inet.h>
40 #include <fcntl.h>
42 #include <stdlib.h>
43 #include <string.h>
45 #include <pthread.h>
47 /*
48 * private variables
49 */
51 static pthread_key_t conn_ctx_key;
52 static _Bool conn_ctx_key_initialized = 0;
54 /*
55 * private types
56 */
58 /* name of connection objects */
59 #define CONN_FD_PREFIX "conn#"
60 #define CONN_FD_PLACEHOLDER "XXXXXXX"
62 static int
63 connection_init(sdb_object_t *obj, va_list ap)
64 {
65 sdb_conn_t *conn;
66 int sock_fd;
67 int sock_fl;
69 assert(obj);
70 conn = CONN(obj);
72 sock_fd = va_arg(ap, int);
74 conn->buf = sdb_strbuf_create(/* size = */ 128);
75 if (! conn->buf) {
76 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
77 "for a new connection");
78 return -1;
79 }
80 conn->errbuf = sdb_strbuf_create(0);
81 if (! conn->errbuf) {
82 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
83 "for a new connection");
84 return -1;
85 }
87 conn->client_addr_len = sizeof(conn->client_addr);
88 conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
89 &conn->client_addr_len);
91 if (conn->fd < 0) {
92 char buf[1024];
93 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
94 "connection: %s", sdb_strerror(errno,
95 buf, sizeof(buf)));
96 return -1;
97 }
99 if (conn->client_addr.ss_family != AF_UNIX) {
100 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
101 "unexpected family type %d", conn->client_addr.ss_family);
102 return -1;
103 }
105 sock_fl = fcntl(conn->fd, F_GETFL);
106 if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
107 char buf[1024];
108 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
109 "to non-blocking mode: %s", conn->fd,
110 sdb_strerror(errno, buf, sizeof(buf)));
111 return -1;
112 }
114 sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
115 conn->fd);
117 conn->cmd = CONNECTION_IDLE;
118 conn->cmd_len = 0;
120 /* update the object name */
121 snprintf(obj->name + strlen(CONN_FD_PREFIX),
122 strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
123 return 0;
124 } /* connection_init */
126 static void
127 connection_destroy(sdb_object_t *obj)
128 {
129 sdb_conn_t *conn;
130 size_t len;
132 assert(obj);
133 conn = CONN(obj);
135 if (conn->buf) {
136 len = sdb_strbuf_len(conn->buf);
137 if (len)
138 sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
139 "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
140 }
142 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection on fd=%i",
143 conn->fd);
144 close(conn->fd);
145 conn->fd = -1;
147 sdb_strbuf_destroy(conn->buf);
148 conn->buf = NULL;
149 sdb_strbuf_destroy(conn->errbuf);
150 conn->errbuf = NULL;
151 } /* connection_destroy */
153 static sdb_type_t connection_type = {
154 /* size = */ sizeof(sdb_conn_t),
155 /* init = */ connection_init,
156 /* destroy = */ connection_destroy,
157 };
159 /*
160 * private helper functions
161 */
163 static void
164 sdb_conn_ctx_destructor(void *c)
165 {
166 sdb_object_t *conn = c;
168 if (! conn)
169 return;
170 sdb_object_deref(conn);
171 } /* sdb_conn_ctx_destructor */
173 static void
174 sdb_conn_ctx_init(void)
175 {
176 if (conn_ctx_key_initialized)
177 return;
179 pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
180 conn_ctx_key_initialized = 1;
181 } /* sdb_conn_ctx_init */
183 static void
184 sdb_conn_set_ctx(sdb_conn_t *conn)
185 {
186 sdb_conn_ctx_init();
187 if (conn)
188 sdb_object_ref(SDB_OBJ(conn));
189 pthread_setspecific(conn_ctx_key, conn);
190 } /* sdb_conn_set_ctx */
192 static sdb_conn_t *
193 sdb_conn_get_ctx(void)
194 {
195 if (! conn_ctx_key_initialized)
196 return NULL;
197 return pthread_getspecific(conn_ctx_key);
198 } /* sdb_conn_get_ctx */
200 /*
201 * connection handler functions
202 */
204 /*
205 * connection_log:
206 * Send a log message originating from the current thread to the client.
207 */
208 static int
209 connection_log(int __attribute__((unused)) prio, const char *msg,
210 sdb_object_t __attribute__((unused)) *user_data)
211 {
212 sdb_conn_t *conn;
214 conn = sdb_conn_get_ctx();
215 /* no connection associated to this thread
216 * or user not authenticated yet => don't leak any information */
217 if ((! conn) || (! conn->username))
218 return 0;
220 /* TODO: Use CONNECTION_LOG_<prio>? */
221 if (sdb_connection_send(conn, CONNECTION_LOG,
222 (uint32_t)strlen(msg), msg) < 0)
223 return -1;
224 return 0;
225 } /* connection_log */
227 static uint32_t
228 connection_get_int32(sdb_conn_t *conn, size_t offset)
229 {
230 const char *data;
231 uint32_t n;
233 assert(conn && (sdb_strbuf_len(conn->buf) >= offset + sizeof(uint32_t)));
235 data = sdb_strbuf_string(conn->buf);
236 memcpy(&n, data + offset, sizeof(n));
237 n = ntohl(n);
238 return n;
239 } /* connection_get_int32 */
241 static int
242 command_handle(sdb_conn_t *conn)
243 {
244 int status = -1;
246 assert(conn && (conn->cmd != CONNECTION_IDLE));
248 sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
249 conn->cmd, conn->cmd_len);
251 if ((! conn->username) && (conn->cmd != CONNECTION_STARTUP)) {
252 const char *errmsg = "Authentication required";
253 sdb_connection_send(conn, CONNECTION_ERROR,
254 (uint32_t)strlen(errmsg), errmsg);
255 return -1;
256 }
258 /* reset */
259 sdb_strbuf_sprintf(conn->errbuf, "");
261 switch (conn->cmd) {
262 case CONNECTION_PING:
263 status = sdb_connection_ping(conn);
264 break;
265 case CONNECTION_STARTUP:
266 status = sdb_fe_session_start(conn);
267 break;
269 case CONNECTION_QUERY:
270 {
271 sdb_llist_t *parsetree;
272 sdb_conn_node_t *node = NULL;
274 parsetree = sdb_fe_parse(sdb_strbuf_string(conn->buf),
275 (int)conn->cmd_len);
276 if (! parsetree) {
277 sdb_log(SDB_LOG_ERR, "frontend: Failed to parse query '%s'",
278 sdb_strbuf_string(conn->buf));
279 status = -1;
280 break;
281 }
283 switch (sdb_llist_len(parsetree)) {
284 case 0:
285 /* skipping empty command */
286 break;
287 case 1:
288 node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
289 break;
291 default:
292 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring %d command%s "
293 "in multi-statement query '%s'",
294 sdb_llist_len(parsetree) - 1,
295 sdb_llist_len(parsetree) == 2 ? "" : "s",
296 sdb_strbuf_string(conn->buf));
297 node = SDB_CONN_NODE(sdb_llist_get(parsetree, 0));
298 }
300 if (node)
301 status = sdb_fe_exec(conn, node);
303 sdb_llist_destroy(parsetree);
304 break;
305 }
307 case CONNECTION_LIST:
308 status = sdb_fe_list(conn);
309 break;
311 default:
312 {
313 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
314 conn->cmd);
315 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
316 status = -1;
317 break;
318 }
319 }
321 if (status)
322 sdb_connection_send(conn, CONNECTION_ERROR,
323 (uint32_t)sdb_strbuf_len(conn->errbuf),
324 sdb_strbuf_string(conn->errbuf));
326 /* remove the command from the buffer */
327 if (conn->cmd_len)
328 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
329 conn->cmd = CONNECTION_IDLE;
330 conn->cmd_len = 0;
331 return status;
332 } /* command_handle */
334 /* initialize the connection state information */
335 static int
336 command_init(sdb_conn_t *conn)
337 {
338 size_t len;
340 assert(conn && (conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len));
342 conn->cmd = connection_get_int32(conn, 0);
343 conn->cmd_len = connection_get_int32(conn, sizeof(uint32_t));
345 len = 2 * sizeof(uint32_t);
346 if (conn->cmd == CONNECTION_IDLE)
347 len += conn->cmd_len;
348 sdb_strbuf_skip(conn->buf, 0, len);
349 return 0;
350 } /* command_init */
352 /* returns negative value on error, 0 on EOF, number of octets else */
353 static ssize_t
354 connection_read(sdb_conn_t *conn)
355 {
356 ssize_t n = 0;
358 while (42) {
359 ssize_t status;
361 errno = 0;
362 status = sdb_strbuf_read(conn->buf, conn->fd, 1024);
363 if (status < 0) {
364 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
365 break;
366 return (int)status;
367 }
368 else if (! status) /* EOF */
369 break;
371 n += status;
372 }
374 return n;
375 } /* connection_read */
377 /*
378 * public API
379 */
381 int
382 sdb_connection_enable_logging(void)
383 {
384 return sdb_plugin_register_log("connection-logger", connection_log,
385 /* user_data = */ NULL);
386 } /* sdb_connection_enable_logging */
388 sdb_conn_t *
389 sdb_connection_accept(int fd)
390 {
391 if (fd < 0)
392 return NULL;
394 /* the placeholder will be replaced with the accepted file
395 * descriptor when initializing the object */
396 return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
397 connection_type, fd));
398 } /* sdb_connection_create */
400 void
401 sdb_connection_close(sdb_conn_t *conn)
402 {
403 sdb_object_deref(SDB_OBJ(conn));
404 } /* sdb_connection_close */
406 ssize_t
407 sdb_connection_read(sdb_conn_t *conn)
408 {
409 ssize_t n = 0;
411 sdb_conn_set_ctx(conn);
413 while (42) {
414 ssize_t status = connection_read(conn);
416 if ((conn->cmd == CONNECTION_IDLE) && (! conn->cmd_len)
417 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
418 command_init(conn);
419 if ((conn->cmd != CONNECTION_IDLE)
420 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len))
421 command_handle(conn);
423 if (status <= 0)
424 break;
426 n += status;
427 }
429 sdb_conn_set_ctx(NULL);
430 return n;
431 } /* sdb_connection_read */
433 ssize_t
434 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
435 uint32_t msg_len, const char *msg)
436 {
437 ssize_t status;
439 if ((! conn) || (conn->fd < 0))
440 return -1;
442 status = sdb_proto_send_msg(conn->fd, code, msg_len, msg);
443 if (status < 0) {
444 char errbuf[1024];
446 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
447 "(code: %u, len: %u) to client: %s", code, msg_len,
448 sdb_strerror(errno, errbuf, sizeof(errbuf)));
449 }
450 return status;
451 } /* sdb_connection_send */
453 int
454 sdb_connection_ping(sdb_conn_t *conn)
455 {
456 if ((! conn) || (conn->cmd != CONNECTION_PING))
457 return -1;
459 /* we're alive */
460 sdb_connection_send(conn, CONNECTION_OK, 0, NULL);
461 return 0;
462 } /* sdb_connection_ping */
464 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */