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 <sys/socket.h>
51 #include <sys/types.h>
52 #include <sys/param.h>
54 #ifdef HAVE_UCRED_H
55 # include <ucred.h>
56 #endif
57 #ifdef HAVE_SYS_UCRED_H
58 # include <sys/ucred.h>
59 #endif
61 #include <pwd.h>
63 #include <pthread.h>
65 /*
66 * private variables
67 */
69 static pthread_key_t conn_ctx_key;
70 static bool conn_ctx_key_initialized = 0;
72 /*
73 * private types
74 */
76 /* name of connection objects */
77 #define CONN_FD_PREFIX "conn#"
78 #define CONN_FD_PLACEHOLDER "XXXXXXX"
80 /* XXX: only supports UNIX sockets so far */
81 static char *
82 peer(int sockfd)
83 {
84 uid_t uid;
86 struct passwd pw_entry;
87 struct passwd *result = NULL;
88 char buf[1024];
90 #ifdef SO_PEERCRED
91 struct ucred cred;
92 socklen_t len = sizeof(cred);
94 if (getsockopt(sockfd, SOL_SOCKET, SO_PEERCRED, &cred, &len)
95 || (len != sizeof(cred)))
96 return NULL;
97 uid = cred.uid;
98 #else /* SO_PEERCRED */
99 errno = ENOSYS;
100 return NULL;
101 #endif
103 memset(&pw_entry, 0, sizeof(pw_entry));
104 if (getpwuid_r(uid, &pw_entry, buf, sizeof(buf), &result)
105 || (! result))
106 return NULL;
107 return strdup(result->pw_name);
108 } /* peer */
110 static ssize_t
111 conn_read(sdb_conn_t *conn, size_t len)
112 {
113 return sdb_strbuf_read(conn->buf, conn->fd, len);
114 } /* conn_read */
116 static ssize_t
117 conn_write(sdb_conn_t *conn, const void *buf, size_t len)
118 {
119 return sdb_write(conn->fd, len, buf);
120 } /* conn_write */
122 static int
123 connection_init(sdb_object_t *obj, va_list ap)
124 {
125 sdb_conn_t *conn;
126 int sock_fd;
127 int sock_fl;
129 assert(obj);
130 conn = CONN(obj);
132 sock_fd = va_arg(ap, int);
134 conn->buf = sdb_strbuf_create(/* size = */ 128);
135 if (! conn->buf) {
136 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate a read buffer "
137 "for a new connection");
138 return -1;
139 }
140 conn->errbuf = sdb_strbuf_create(0);
141 if (! conn->errbuf) {
142 sdb_log(SDB_LOG_ERR, "frontend: Failed to allocate an error buffer "
143 "for a new connection");
144 return -1;
145 }
147 conn->client_addr_len = sizeof(conn->client_addr);
148 conn->fd = accept(sock_fd, (struct sockaddr *)&conn->client_addr,
149 &conn->client_addr_len);
151 if (conn->fd < 0) {
152 char buf[1024];
153 sdb_log(SDB_LOG_ERR, "frontend: Failed to accept remote "
154 "connection: %s", sdb_strerror(errno,
155 buf, sizeof(buf)));
156 return -1;
157 }
159 /* defaults */
160 conn->read = conn_read;
161 conn->write = conn_write;
162 conn->finish = NULL;
163 conn->session = NULL;
165 if (conn->client_addr.ss_family != AF_UNIX) {
166 sdb_log(SDB_LOG_ERR, "frontend: Accepted connection using "
167 "unexpected family type %d", conn->client_addr.ss_family);
168 return -1;
169 }
171 sock_fl = fcntl(conn->fd, F_GETFL);
172 if (fcntl(conn->fd, F_SETFL, sock_fl | O_NONBLOCK)) {
173 char buf[1024];
174 sdb_log(SDB_LOG_ERR, "frontend: Failed to switch connection conn#%i "
175 "to non-blocking mode: %s", conn->fd,
176 sdb_strerror(errno, buf, sizeof(buf)));
177 return -1;
178 }
180 conn->username = peer(conn->fd);
181 if (! conn->username) {
182 char buf[1024];
183 sdb_log(SDB_LOG_ERR, "frontend: Failed to retrieve peer for "
184 "connection conn#%i: %s", conn->fd,
185 sdb_strerror(errno, buf, sizeof(buf)));
186 return -1;
187 }
188 conn->ready = 0;
190 sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
191 conn->fd);
193 conn->cmd = SDB_CONNECTION_IDLE;
194 conn->cmd_len = 0;
195 conn->skip_len = 0;
197 /* update the object name */
198 snprintf(obj->name + strlen(CONN_FD_PREFIX),
199 strlen(CONN_FD_PLACEHOLDER), "%i", conn->fd);
200 return 0;
201 } /* connection_init */
203 static void
204 connection_destroy(sdb_object_t *obj)
205 {
206 sdb_conn_t *conn;
207 size_t len;
209 assert(obj);
210 conn = CONN(obj);
212 conn->ready = 0;
214 if (conn->finish)
215 conn->finish(conn);
216 conn->finish = NULL;
218 if (conn->buf) {
219 len = sdb_strbuf_len(conn->buf);
220 if (len)
221 sdb_log(SDB_LOG_INFO, "frontend: Discarding incomplete command "
222 "(%zu byte%s left in buffer)", len, len == 1 ? "" : "s");
223 }
225 sdb_log(SDB_LOG_DEBUG, "frontend: Closing connection %s", obj->name);
226 sdb_connection_close(conn);
228 if (conn->username)
229 free(conn->username);
230 conn->username = NULL;
232 sdb_strbuf_destroy(conn->buf);
233 conn->buf = NULL;
234 sdb_strbuf_destroy(conn->errbuf);
235 conn->errbuf = NULL;
236 } /* connection_destroy */
238 static sdb_type_t connection_type = {
239 /* size = */ sizeof(sdb_conn_t),
240 /* init = */ connection_init,
241 /* destroy = */ connection_destroy,
242 };
244 /*
245 * private helper functions
246 */
248 static void
249 sdb_conn_ctx_destructor(void *c)
250 {
251 sdb_object_t *conn = c;
253 if (! conn)
254 return;
255 sdb_object_deref(conn);
256 } /* sdb_conn_ctx_destructor */
258 static void
259 sdb_conn_ctx_init(void)
260 {
261 if (conn_ctx_key_initialized)
262 return;
264 pthread_key_create(&conn_ctx_key, sdb_conn_ctx_destructor);
265 conn_ctx_key_initialized = 1;
266 } /* sdb_conn_ctx_init */
268 static void
269 sdb_conn_set_ctx(sdb_conn_t *conn)
270 {
271 sdb_conn_t *old;
273 sdb_conn_ctx_init();
275 old = pthread_getspecific(conn_ctx_key);
276 if (old)
277 sdb_object_deref(SDB_OBJ(old));
278 if (conn)
279 sdb_object_ref(SDB_OBJ(conn));
280 pthread_setspecific(conn_ctx_key, conn);
281 } /* sdb_conn_set_ctx */
283 static sdb_conn_t *
284 sdb_conn_get_ctx(void)
285 {
286 if (! conn_ctx_key_initialized)
287 return NULL;
288 return pthread_getspecific(conn_ctx_key);
289 } /* sdb_conn_get_ctx */
291 /*
292 * connection handler functions
293 */
295 /*
296 * connection_log:
297 * Send a log message originating from the current thread to the client.
298 */
299 static int
300 connection_log(int prio, const char *msg,
301 sdb_object_t __attribute__((unused)) *user_data)
302 {
303 uint32_t len = (uint32_t)sizeof(uint32_t) + (uint32_t)strlen(msg);
304 uint32_t p = htonl((uint32_t)prio);
305 char tmp[len + 1];
307 sdb_conn_t *conn;
309 conn = sdb_conn_get_ctx();
310 /* no connection associated to this thread
311 * or startup not done yet => don't leak any information */
312 if ((! conn) || (! conn->ready))
313 return 0;
315 /* XXX: make the log-level configurable by the client at runtime */
316 if (prio >= SDB_LOG_DEBUG)
317 return 0;
319 memcpy(tmp, &p, sizeof(p));
320 strcpy(tmp + sizeof(p), msg);
322 if (sdb_connection_send(conn, SDB_CONNECTION_LOG, len, tmp) < 0)
323 return -1;
324 return 0;
325 } /* connection_log */
327 static int
328 command_handle(sdb_conn_t *conn)
329 {
330 int status = -1;
332 assert(conn && (conn->cmd != SDB_CONNECTION_IDLE));
333 assert(! conn->skip_len);
335 sdb_log(SDB_LOG_DEBUG, "frontend: Handling command %u (len: %u)",
336 conn->cmd, conn->cmd_len);
338 if (conn->cmd == SDB_CONNECTION_PING)
339 status = sdb_connection_ping(conn);
340 else if (conn->cmd == SDB_CONNECTION_STARTUP)
341 status = sdb_fe_session_start(conn);
342 else if (conn->cmd == SDB_CONNECTION_QUERY)
343 status = sdb_fe_query(conn);
344 else if (conn->cmd == SDB_CONNECTION_FETCH)
345 status = sdb_fe_fetch(conn);
346 else if (conn->cmd == SDB_CONNECTION_LIST)
347 status = sdb_fe_list(conn);
348 else if (conn->cmd == SDB_CONNECTION_LOOKUP)
349 status = sdb_fe_lookup(conn);
350 else if (conn->cmd == SDB_CONNECTION_STORE)
351 status = sdb_fe_store(conn);
352 else {
353 sdb_log(SDB_LOG_WARNING, "frontend: Ignoring invalid command %#x",
354 conn->cmd);
355 sdb_strbuf_sprintf(conn->errbuf, "Invalid command %#x", conn->cmd);
356 status = -1;
357 }
359 if (status) {
360 if (! sdb_strbuf_len(conn->errbuf))
361 sdb_strbuf_sprintf(conn->errbuf, "Failed to execute command");
362 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
363 (uint32_t)sdb_strbuf_len(conn->errbuf),
364 sdb_strbuf_string(conn->errbuf));
365 }
366 return status;
367 } /* command_handle */
369 /* initialize the connection state information */
370 static int
371 command_init(sdb_conn_t *conn)
372 {
373 const char *errmsg = NULL;
375 assert(conn && (conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len));
377 if (conn->skip_len)
378 return -1;
380 /* reset */
381 sdb_strbuf_clear(conn->errbuf);
383 if (sdb_proto_unmarshal_header(SDB_STRBUF_STR(conn->buf),
384 &conn->cmd, &conn->cmd_len) < 0)
385 return -1;
386 sdb_strbuf_skip(conn->buf, 0, 2 * sizeof(uint32_t));
388 if ((! conn->ready) && (conn->cmd != SDB_CONNECTION_STARTUP))
389 errmsg = "Authentication required";
390 else if (conn->cmd == SDB_CONNECTION_IDLE)
391 errmsg = "Invalid command 0";
393 if (errmsg) {
394 size_t len = sdb_strbuf_len(conn->buf);
396 sdb_strbuf_sprintf(conn->errbuf, "%s", errmsg);
397 sdb_connection_send(conn, SDB_CONNECTION_ERROR,
398 (uint32_t)strlen(errmsg), errmsg);
399 conn->skip_len += conn->cmd_len;
400 conn->cmd = SDB_CONNECTION_IDLE;
401 conn->cmd_len = 0;
403 if (len > conn->skip_len)
404 len = conn->skip_len;
405 sdb_strbuf_skip(conn->buf, 0, len);
406 conn->skip_len -= len;
407 /* connection_read will handle anything else */
408 }
409 return 0;
410 } /* command_init */
412 /* returns negative value on error, 0 on EOF, number of octets else */
413 static ssize_t
414 connection_read(sdb_conn_t *conn)
415 {
416 ssize_t n = 0;
418 if ((! conn) || (conn->fd < 0))
419 return -1;
421 while (42) {
422 ssize_t status;
424 errno = 0;
425 status = conn->read(conn, 1024);
426 if (status < 0) {
427 if ((errno == EAGAIN) || (errno == EWOULDBLOCK))
428 break;
430 sdb_connection_close(conn);
431 return (int)status;
432 }
433 else if (! status) /* EOF */
434 break;
436 if (conn->skip_len) {
437 size_t len = (size_t)status < conn->skip_len
438 ? (size_t)status : conn->skip_len;
439 sdb_strbuf_skip(conn->buf, 0, len);
440 conn->skip_len -= len;
441 }
443 n += status;
445 /* give the main loop a chance to execute commands (and free up buffer
446 * space) on large amounts of incoming traffic */
447 if (n > 1024 * 1024)
448 break;
449 }
451 return n;
452 } /* connection_read */
454 /*
455 * public API
456 */
458 int
459 sdb_connection_enable_logging(void)
460 {
461 return sdb_plugin_register_log("connection-logger", connection_log,
462 /* user_data = */ NULL);
463 } /* sdb_connection_enable_logging */
465 sdb_conn_t *
466 sdb_connection_accept(int fd)
467 {
468 if (fd < 0)
469 return NULL;
471 /* the placeholder will be replaced with the accepted file
472 * descriptor when initializing the object */
473 return CONN(sdb_object_create(CONN_FD_PREFIX CONN_FD_PLACEHOLDER,
474 connection_type, fd));
475 } /* sdb_connection_create */
477 void
478 sdb_connection_close(sdb_conn_t *conn)
479 {
480 if (! conn)
481 return;
483 if (conn->finish)
484 conn->finish(conn);
485 conn->finish = NULL;
487 /* close the connection even if someone else still references it */
488 if (conn->fd >= 0)
489 close(conn->fd);
490 conn->fd = -1;
491 } /* sdb_connection_close */
493 ssize_t
494 sdb_connection_handle(sdb_conn_t *conn)
495 {
496 ssize_t n = 0;
498 sdb_conn_set_ctx(conn);
500 while (42) {
501 ssize_t status = connection_read(conn);
503 if ((conn->cmd == SDB_CONNECTION_IDLE) && (! conn->cmd_len)
504 && (sdb_strbuf_len(conn->buf) >= 2 * sizeof(int32_t)))
505 command_init(conn);
506 if ((conn->cmd != SDB_CONNECTION_IDLE)
507 && (sdb_strbuf_len(conn->buf) >= conn->cmd_len)) {
508 command_handle(conn);
510 /* remove the command from the buffer */
511 if (conn->cmd_len)
512 sdb_strbuf_skip(conn->buf, 0, conn->cmd_len);
513 conn->cmd = SDB_CONNECTION_IDLE;
514 conn->cmd_len = 0;
515 }
517 if (status <= 0)
518 break;
520 n += status;
521 }
523 sdb_conn_set_ctx(NULL);
524 return n;
525 } /* sdb_connection_handle */
527 ssize_t
528 sdb_connection_send(sdb_conn_t *conn, uint32_t code,
529 uint32_t msg_len, const char *msg)
530 {
531 char buf[2 * sizeof(uint32_t) + msg_len];
532 ssize_t status;
534 if ((! conn) || (conn->fd < 0))
535 return -1;
536 if (sdb_proto_marshal(buf, sizeof(buf), code, msg_len, msg) < 0)
537 return -1;
539 status = conn->write(conn, buf, sizeof(buf));
540 if (status < 0) {
541 char errbuf[1024];
543 /* tell other code that there was a problem and, more importantly,
544 * make sure we don't try to send further logs to the connection */
545 sdb_connection_close(conn);
546 conn->ready = 0;
548 sdb_log(SDB_LOG_ERR, "frontend: Failed to send msg "
549 "(code: %u, len: %u) to client: %s", code, msg_len,
550 sdb_strerror(errno, errbuf, sizeof(errbuf)));
551 }
552 return status;
553 } /* sdb_connection_send */
555 int
556 sdb_connection_ping(sdb_conn_t *conn)
557 {
558 if ((! conn) || (conn->cmd != SDB_CONNECTION_PING))
559 return -1;
561 /* we're alive */
562 sdb_connection_send(conn, SDB_CONNECTION_OK, 0, NULL);
563 return 0;
564 } /* sdb_connection_ping */
566 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */