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 #ifdef HAVE_CONFIG_H
29 # include "config.h"
30 #endif
32 #include "sysdb.h"
33 #include "core/object.h"
34 #include "core/plugin.h"
35 #include "frontend/connection-private.h"
36 #include "utils/error.h"
37 #include "utils/strbuf.h"
38 #include "utils/proto.h"
39 #include "utils/os.h"
41 #include <assert.h>
42 #include <errno.h>
44 #include <arpa/inet.h>
45 #include <fcntl.h>
47 #include <stdlib.h>
48 #include <string.h>
50 #include <pthread.h>
52 /*
53 * private variables
54 */
56 static pthread_key_t conn_ctx_key;
57 static bool conn_ctx_key_initialized = 0;
59 /*
60 * private types
61 */
63 /* name of connection objects */
64 #define CONN_FD_PREFIX "conn#"
65 #define CONN_FD_PLACEHOLDER "XXXXXXX"
67 static ssize_t
68 conn_read(sdb_conn_t *conn, size_t len)
69 {
70 return sdb_strbuf_read(conn->buf, conn->fd, len);
71 } /* conn_read */
73 static ssize_t
74 conn_write(sdb_conn_t *conn, const void *buf, size_t len)
75 {
76 return sdb_write(conn->fd, len, buf);
77 } /* conn_write */
79 static int
80 connection_init(sdb_object_t *obj, va_list ap)
81 {
82 sdb_conn_t *conn;
83 int sock_fd;
84 int sock_fl;
86 assert(obj);
87 conn = CONN(obj);
89 sock_fd = va_arg(ap, int);
91 conn->buf = sdb_strbuf_create(/* size = */ 128);
92 if (! conn->buf) {
93 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
94 "for a new connection");
95 return -1;
96 }
97 conn->errbuf = sdb_strbuf_create(0);
98 if (! conn->errbuf) {
99 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
100 "for a new connection");
101 return -1;
102 }
104 conn->client_addr_len = sizeof(conn->client_addr);
105 conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
106 &conn->client_addr_len);
108 if (conn->fd < 0) {
109 char buf[1024];
110 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
111 "connection: %s", sdb_strerror(errno,
112 buf, sizeof(buf)));
113 return -1;
114 }
116 /* update the object name */
117 snprintf(obj->name + strlen(CONN_FD_PREFIX),
118 strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
120 /* defaults */
121 conn->read = conn_read;
122 conn->write = conn_write;
123 conn->finish = NULL;
124 conn->session = NULL;
126 sock_fl = fcntl(conn->fd, F_GETFL);
127 if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
128 char buf[1024];
129 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
130 "to non-blocking mode: %s", conn->fd,
131 sdb_strerror(errno, buf, sizeof(buf)));
132 return -1;
133 }
135 conn->username = NULL;
136 conn->ready = 0;
138 sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
139 conn->fd);
141 conn->cmd = SDB_CONNECTION_IDLE;
142 conn->cmd_len = 0;
143 conn->skip_len = 0;
144 return 0;
145 } /* connection_init */
147 static void
148 connection_destroy(sdb_object_t *obj)
149 {
150 sdb_conn_t *conn;
151 size_t len;
153 assert(obj);
154 conn = CONN(obj);
156 conn->ready = 0;
158 if (conn->finish)
159 conn->finish(conn);
160 conn->finish = NULL;
162 if (conn->buf) {
163 len = sdb_strbuf_len(conn->buf);
164 if (len)
165 sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
166 "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
167 }
169 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
170 sdb_connection_close(conn);
172 if (conn->username)
173 free(conn->username);
174 conn->username = NULL;
176 sdb_strbuf_destroy(conn->buf);
177 conn->buf = NULL;
178 sdb_strbuf_destroy(conn->errbuf);
179 conn->errbuf = NULL;
180 } /* connection_destroy */
182 static sdb_type_t connection_type = {
183 /* size = */ sizeof(sdb_conn_t),
184 /* init = */ connection_init,
185 /* destroy = */ connection_destroy,
186 };
188 /*
189 * private helper functions
190 */
192 static void
193 sdb_conn_ctx_destructor(void *c)
194 {
195 sdb_object_t *conn = c;
197 if (! conn)
198 return;
199 sdb_object_deref(conn);
200 } /* sdb_conn_ctx_destructor */
202 static void
203 sdb_conn_ctx_init(void)
204 {
205 if (conn_ctx_key_initialized)
206 return;
208 pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
209 conn_ctx_key_initialized = 1;
210 } /* sdb_conn_ctx_init */
212 static void
213 sdb_conn_set_ctx(sdb_conn_t *conn)
214 {
215 sdb_conn_t *old;
217 sdb_conn_ctx_init();
219 old = pthread_getspecific(conn_ctx_key);
220 if (old)
221 sdb_object_deref(SDB_OBJ(old));
222 if (conn)
223 sdb_object_ref(SDB_OBJ(conn));
224 pthread_setspecific(conn_ctx_key, conn);
225 } /* sdb_conn_set_ctx */
227 static sdb_conn_t *
228 sdb_conn_get_ctx(void)
229 {
230 if (! conn_ctx_key_initialized)
231 return NULL;
232 return pthread_getspecific(conn_ctx_key);
233 } /* sdb_conn_get_ctx */
235 /*
236 * connection handler functions
237 */
239 /*
240 * connection_log:
241 * Send a log message originating from the current thread to the client.
242 */
243 static int
244 connection_log(int prio, const char *msg,
245 sdb_object_t __attribute__((unused)) *user_data)
246 {
247 uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
248 uint32_t p = htonl((uint32_t)prio);
249 char tmp[len + 1];
251 sdb_conn_t *conn;
253 conn = sdb_conn_get_ctx();
254 /* no connection associated to this thread
255 * or startup not done yet => don't leak any information */
256 if ((! conn) || (! conn->ready))
257 return 0;
259 /* XXX: make the log-level configurable by the client at runtime */
260 if (prio >= SDB_LOG_DEBUG)
261 return 0;
263 memcpy(tmp, &p, sizeof(p));
264 strcpy(tmp + sizeof(p), msg);
266 if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
267 return -1;
268 return 0;
269 } /* connection_log */
271 static int
272 command_handle(sdb_conn_t *conn)
273 {
274 int status = -1;
276 assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
277 assert(! conn->skip_len);
279 sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
280 conn->cmd, conn->cmd_len);
282 if (conn->cmd == SDB_CONNECTION_PING)
283 status = sdb_connection_ping(conn);
284 else if (conn->cmd == SDB_CONNECTION_STARTUP)
285 status = sdb_fe_session_start(conn);
286 else if (conn->cmd == SDB_CONNECTION_QUERY)
287 status = sdb_fe_query(conn);
288 else if (conn->cmd == SDB_CONNECTION_FETCH)
289 status = sdb_fe_fetch(conn);
290 else if (conn->cmd == SDB_CONNECTION_LIST)
291 status = sdb_fe_list(conn);
292 else if (conn->cmd == SDB_CONNECTION_LOOKUP)
293 status = sdb_fe_lookup(conn);
294 else if (conn->cmd == SDB_CONNECTION_STORE)
295 status = sdb_fe_store(conn);
296 else {
297 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
298 conn->cmd);
299 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
300 status = -1;
301 }
303 if (status) {
304 if (! sdb_strbuf_len(conn->errbuf))
305 sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
306 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
307 (uint32_t)sdb_strbuf_len(conn->errbuf),
308 sdb_strbuf_string(conn->errbuf));
309 }
310 return status;
311 } /* command_handle */
313 /* initialize the connection state information */
314 static int
315 command_init(sdb_conn_t *conn)
316 {
317 const char *errmsg = NULL;
319 assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
321 if (conn->skip_len)
322 return -1;
324 /* reset */
325 sdb_strbuf_clear(conn->errbuf);
327 if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
328 &conn->cmd, &conn->cmd_len) < 0)
329 return -1;
330 sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
332 if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
333 errmsg = "Authentication required";
334 else if (conn->cmd == SDB_CONNECTION_IDLE)
335 errmsg = "Invalid command 0";
337 if (errmsg) {
338 size_t len = sdb_strbuf_len(conn->buf);
340 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
341 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
342 (uint32_t)strlen(errmsg), errmsg);
343 conn->skip_len += conn->cmd_len;
344 conn->cmd = SDB_CONNECTION_IDLE;
345 conn->cmd_len = 0;
347 if (len > conn->skip_len)
348 len = conn->skip_len;
349 sdb_strbuf_skip(conn->buf, 0, len);
350 conn->skip_len -= len;
351 /* connection_read will handle anything else */
352 }
353 return 0;
354 } /* command_init */
356 /* returns negative value on error, 0 on EOF, number of octets else */
357 static ssize_t
358 connection_read(sdb_conn_t *conn)
359 {
360 ssize_t n = 0;
362 if ((! conn) || (conn->fd < 0))
363 return -1;
365 while (42) {
366 ssize_t status;
368 errno = 0;
369 status = conn->read(conn, 1024);
370 if (status < 0) {
371 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
372 break;
374 sdb_connection_close(conn);
375 return (int)status;
376 }
377 else if (! status) /* EOF */
378 break;
380 if (conn->skip_len) {
381 size_t len = (size_t)status < conn->skip_len
382 ? (size_t)status : conn->skip_len;
383 sdb_strbuf_skip(conn->buf, 0, len);
384 conn->skip_len -= len;
385 }
387 n += status;
389 /* give the main loop a chance to execute commands (and free up buffer
390 * space) on large amounts of incoming traffic */
391 if (n > 1024 * 1024)
392 break;
393 }
395 return n;
396 } /* connection_read */
398 /*
399 * public API
400 */
402 int
403 sdb_connection_enable_logging(void)
404 {
405 return sdb_plugin_register_log("connection-logger", connection_log,
406 /* user_data = */ NULL);
407 } /* sdb_connection_enable_logging */
409 sdb_conn_t *
410 sdb_connection_accept(int fd)
411 {
412 if (fd < 0)
413 return NULL;
415 /* the placeholder will be replaced with the accepted file
416 * descriptor when initializing the object */
417 return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
418 connection_type, fd));
419 } /* sdb_connection_create */
421 void
422 sdb_connection_close(sdb_conn_t *conn)
423 {
424 if (! conn)
425 return;
427 if (conn->finish)
428 conn->finish(conn);
429 conn->finish = NULL;
431 /* close the connection even if someone else still references it */
432 if (conn->fd >= 0)
433 close(conn->fd);
434 conn->fd = -1;
435 } /* sdb_connection_close */
437 ssize_t
438 sdb_connection_handle(sdb_conn_t *conn)
439 {
440 ssize_t n = 0;
442 sdb_conn_set_ctx(conn);
444 while (42) {
445 ssize_t status = connection_read(conn);
447 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
448 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
449 command_init(conn);
450 if ((conn->cmd != SDB_CONNECTION_IDLE)
451 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
452 command_handle(conn);
454 /* remove the command from the buffer */
455 if (conn->cmd_len)
456 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
457 conn->cmd = SDB_CONNECTION_IDLE;
458 conn->cmd_len = 0;
459 }
461 if (status <= 0)
462 break;
464 n += status;
465 }
467 sdb_conn_set_ctx(NULL);
468 return n;
469 } /* sdb_connection_handle */
471 ssize_t
472 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
473 uint32_t msg_len, const char *msg)
474 {
475 char buf[2 * sizeof(uint32_t) + msg_len];
476 ssize_t status;
478 if ((! conn) || (conn->fd < 0))
479 return -1;
480 if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
481 return -1;
483 status = conn->write(conn, buf, sizeof(buf));
484 if (status < 0) {
485 char errbuf[1024];
487 /* tell other code that there was a problem and, more importantly,
488 * make sure we don't try to send further logs to the connection */
489 sdb_connection_close(conn);
490 conn->ready = 0;
492 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
493 "(code: %u, len: %u) to client: %s", code, msg_len,
494 sdb_strerror(errno, errbuf, sizeof(errbuf)));
495 }
496 return status;
497 } /* sdb_connection_send */
499 int
500 sdb_connection_ping(sdb_conn_t *conn)
501 {
502 if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
503 return -1;
505 /* we're alive */
506 sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
507 return 0;
508 } /* sdb_connection_ping */
510 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */