Make rc4 encryption/decryption more explicit.
[paraslash.git] / net.c
1 /*
2 * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file net.c Networking-related helper functions. */
8
9 /*
10 * Since glibc 2.8, the _GNU_SOURCE feature test macro must be defined in order
11 * to obtain the definition of the ucred structure.
12 */
13 #define _GNU_SOURCE
14
15 #include <netdb.h>
16
17 /* At least NetBSD needs these. */
18 #ifndef AI_V4MAPPED
19 #define AI_V4MAPPED 0
20 #endif
21 #ifndef AI_ALL
22 #define AI_ALL 0
23 #endif
24 #ifndef AI_ADDRCONFIG
25 #define AI_ADDRCONFIG 0
26 #endif
27
28 #include <dirent.h>
29 #include <regex.h>
30 #include <openssl/rc4.h>
31
32 #include "para.h"
33 #include "error.h"
34 #include "crypt.h"
35 #include "net.h"
36 #include "string.h"
37 #include "fd.h"
38
39 /**
40 * Match string as a candidate IPv4 address.
41 *
42 * \param address The string to match.
43 * \return True if \a address has "dot-quad" format.
44 */
45 static bool is_v4_dot_quad(const char *address)
46 {
47 bool result;
48 regex_t r;
49
50 assert(!regcomp(&r, "^([0-9]+\\.){3}[0-9]+$", REG_EXTENDED|REG_NOSUB));
51 result = regexec(&r, address, 0, NULL, 0) == 0;
52 regfree(&r);
53 return result;
54 }
55
56 /**
57 * Perform basic syntax checking on the host-part of an URL:
58 *
59 * - Since ':' is invalid in IPv4 addresses and DNS names, the
60 * presence of ':' causes interpretation as IPv6 address;
61 * - next the first-match-wins algorithm from RFC 3986 is applied;
62 * - else the string is considered as DNS name, to be resolved later.
63 *
64 * \param host The host string to check.
65 * \return True if \a host passes the syntax checks.
66 *
67 * \sa RFC 3986, 3.2.2; RFC 1123, 2.1; RFC 1034, 3.5
68 */
69 static bool host_string_ok(const char *host)
70 {
71 if (host == NULL || *host == '\0')
72 return false;
73 if (strchr(host, ':') != NULL)
74 return is_valid_ipv6_address(host);
75 if (is_v4_dot_quad(host))
76 return is_valid_ipv4_address(host);
77 return true;
78 }
79
80 /**
81 * Parse and validate URL string.
82 *
83 * The URL syntax is loosely based on RFC 3986, supporting one of
84 * - "["host"]"[:port] for native IPv6 addresses and
85 * - host[:port] for IPv4 hostnames and DNS names.
86 *
87 * Native IPv6 addresses must be enclosed in square brackets, since
88 * otherwise there is an ambiguity with the port separator `:'.
89 * The 'port' part is always considered to be a number; if absent,
90 * it is set to -1, to indicate that a default port is to be used.
91 *
92 * The following are valid examples:
93 * - 10.10.1.1
94 * - 10.10.1.2:8000
95 * - localhost
96 * - localhost:8001
97 * - [::1]:8000
98 * - [badc0de::1]
99 *
100 * \param url The URL string to take apart.
101 * \param host To return the copied host part of \a url.
102 * \param hostlen The maximum length of \a host.
103 * \param port To return the port number (if any) of \a url.
104 *
105 * \return Pointer to \a host, or NULL if failed.
106 * If NULL is returned, \a host and \a portnum are undefined. If no
107 * port number was present in \a url, \a portnum is set to -1.
108 *
109 * \sa RFC 3986, 3.2.2/3.2.3
110 */
111 char *parse_url(const char *url,
112 char *host, ssize_t hostlen,
113 int32_t *port)
114 {
115 const char *o = url;
116 char *c = host, *end = c + (hostlen - 1);
117
118 *port = -1;
119
120 if (o == NULL || hostlen < 1)
121 goto failed;
122
123 if (*o == '[') {
124 for (++o; (*c = *o == ']' ? '\0' : *o); c++, o++)
125 if (c == end)
126 goto failed;
127
128 if (*o++ != ']' || (*o != '\0' && *o != ':'))
129 goto failed;
130 } else {
131 for (; (*c = *o == ':'? '\0' : *o); c++, o++)
132 if (c == end)
133 goto failed;
134 }
135
136 if (*o == ':')
137 if (para_atoi32(++o, port) < 0 ||
138 *port < 0 || *port > 0xffff)
139 goto failed;
140
141 if (host_string_ok(host))
142 return host;
143 failed:
144 *host = '\0';
145 return NULL;
146 }
147
148 /**
149 * Determine the socket type for a given layer-4 protocol.
150 *
151 * \param l4type The symbolic name of the transport-layer protocol.
152 *
153 * \sa ip(7), socket(2)
154 */
155 static inline int sock_type(const unsigned l4type)
156 {
157 switch (l4type) {
158 case IPPROTO_UDP: return SOCK_DGRAM;
159 case IPPROTO_TCP: return SOCK_STREAM;
160 case IPPROTO_DCCP: return SOCK_DCCP;
161 }
162 return -1; /* not supported here */
163 }
164
165 /**
166 * Pretty-print transport-layer name.
167 */
168 static const char *layer4_name(const unsigned l4type)
169 {
170 switch (l4type) {
171 case IPPROTO_UDP: return "UDP";
172 case IPPROTO_TCP: return "TCP";
173 case IPPROTO_DCCP: return "DCCP";
174 }
175 return "UNKNOWN PROTOCOL";
176 }
177
178 /**
179 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
180 *
181 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
182 * \param l4type The layer-4 type (\p IPPROTO_xxx).
183 * \param passive Whether this is a passive (1) or active (0) socket.
184 * \param host Remote or local hostname or IPv/6 address string.
185 * \param port_number Decimal port number.
186 *
187 * This creates a ready-made IPv4/v6 socket structure after looking up the
188 * necessary parameters. The interpretation of \a host depends on the value of
189 * \a passive:
190 * - on a passive socket host is interpreted as an interface IPv4/6 address
191 * (can be left NULL);
192 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
193 * to connect to;
194 * - \a port_number is in either case the numeric port number (not service
195 * string).
196 *
197 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
198 * sockets. The algorithm tries all possible address combinations until it
199 * succeeds.
200 *
201 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
202 * matching connection could be set up (with details in the error log).
203 *
204 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
205 */
206 int makesock(unsigned l3type, unsigned l4type, int passive,
207 const char *host, unsigned short port_number)
208 {
209 struct addrinfo *local = NULL, *src,
210 *remote = NULL, *dst, hints;
211 int rc, on = 1, sockfd = -1,
212 socktype = sock_type(l4type);
213 char port[6]; /* port number has at most 5 digits */
214
215 sprintf(port, "%u", port_number);
216 /* Set up address hint structure */
217 memset(&hints, 0, sizeof(hints));
218 hints.ai_family = l3type;
219 hints.ai_socktype = socktype;
220 /*
221 * getaddrinfo does not support SOCK_DCCP, so for the sake of lookup
222 * (and only then) pretend to be UDP.
223 */
224 if (l4type == IPPROTO_DCCP)
225 hints.ai_socktype = SOCK_DGRAM;
226
227 /* only use addresses available on the host */
228 hints.ai_flags = AI_ADDRCONFIG;
229 if (l3type == AF_INET6)
230 /* use v4-mapped-v6 if no v6 addresses found */
231 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
232
233 if (passive && host == NULL)
234 hints.ai_flags |= AI_PASSIVE;
235
236 /* Obtain local/remote address information */
237 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
238 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
239 layer4_name(l4type),
240 host? host : (passive? "[loopback]" : "[localhost]"),
241 port, gai_strerror(rc));
242 return -E_ADDRESS_LOOKUP;
243 }
244
245 /* Iterate over all src/dst combination, exhausting dst first */
246 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
247 if (src && dst && src->ai_family == AF_INET
248 && dst->ai_family == AF_INET6)
249 goto get_next_dst; /* v4 -> v6 is not possible */
250
251 sockfd = socket(src ? src->ai_family : dst->ai_family,
252 socktype, l4type);
253 if (sockfd < 0)
254 goto get_next_dst;
255
256 /*
257 * Set those options that need to be set before establishing
258 * the connection. Reuse the address on passive (listening)
259 * sockets to avoid failure on restart.
260 */
261 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
262 &on, sizeof(on)) == -1) {
263 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
264 strerror(errno));
265 return -ERRNO_TO_PARA_ERROR(errno);
266 }
267
268 if (src) {
269 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
270 close(sockfd);
271 goto get_next_src;
272 }
273 if (!dst) /* bind-only completed successfully */
274 break;
275 }
276
277 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
278 break; /* connection completed successfully */
279 close(sockfd);
280 get_next_dst:
281 if (dst && (dst = dst->ai_next))
282 continue;
283 get_next_src:
284 if (src && (src = src->ai_next)) /* restart inner loop */
285 dst = remote;
286 }
287 if (local)
288 freeaddrinfo(local);
289 if (remote)
290 freeaddrinfo(remote);
291
292 if (src == NULL && dst == NULL) {
293 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
294 layer4_name(l4type), host? host : (passive?
295 "[loopback]" : "[localhost]"), port);
296 return -ERRNO_TO_PARA_ERROR(errno);
297 }
298 return sockfd;
299 }
300
301 /**
302 * Create a passive / listening socket.
303 *
304 * \param l3type The network-layer type (\p AF_xxx).
305 * \param l4type The transport-layer type (\p IPPROTO_xxx).
306 * \param port The decimal port number to listen on.
307 *
308 * \return Positive integer (socket descriptor) on success, negative value
309 * otherwise.
310 *
311 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
312 */
313 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
314 {
315 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
316
317 if (fd > 0) {
318 ret = listen(fd, BACKLOG);
319 if (ret < 0) {
320 close(fd);
321 return -ERRNO_TO_PARA_ERROR(errno);
322 }
323 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
324 layer4_name(l4type), port, fd);
325 }
326 return fd;
327 }
328
329 /**
330 * Print numeric host and port number (beware - uses static char).
331 *
332 * \param sa The IPv4/IPv6 socket address to use.
333 * \param len The length of \p sa.
334 *
335 * \sa getnameinfo(3).
336 */
337 static char *host_and_port(struct sockaddr *sa, socklen_t len)
338 {
339 static char output[NI_MAXHOST + NI_MAXSERV + 2];
340 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
341 int ret;
342
343 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
344 NI_NUMERICHOST | NI_NUMERICSERV);
345 if (ret) {
346 PARA_WARNING_LOG("hostname lookup error (%s).\n",
347 gai_strerror(ret));
348 sprintf(output, "(unknown)");
349 } else
350 sprintf(output, "%s#%s", hbuf, sbuf);
351 return output;
352 }
353
354 /**
355 * Look up the local or remote side of a connected socket structure.
356 *
357 * \param fd The socket descriptor of the connected socket.
358 * \param getname Either \p getsockname() for local, or \p getpeername() for
359 * remote side.
360 *
361 * \return A static character string identifying hostname and port of the
362 * chosen side.
363 *
364 * \sa getsockname(2), getpeername(2).
365 */
366 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
367 socklen_t *))
368 {
369 struct sockaddr_storage ss;
370 socklen_t sslen = sizeof(ss);
371
372 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
373 static char *dont_know = "(don't know)";
374 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
375 fd, strerror(errno));
376 return dont_know;
377 }
378 return host_and_port((struct sockaddr *)&ss, sslen);
379 }
380
381 /**
382 * Look up the local side of a connected socket structure.
383 *
384 * \param sockfd The file descriptor of the socket.
385 *
386 * \return A pointer to a static buffer containing hostname an port. This
387 * buffer must not be freed by the caller.
388 *
389 * \sa remote_name().
390 */
391 char *local_name(int sockfd)
392 {
393 return __get_sock_name(sockfd, getsockname);
394 }
395
396 /**
397 * Look up the remote side of a connected socket structure.
398 *
399 * \param sockfd The file descriptor of the socket.
400 *
401 * \return Analogous to the return value of \ref local_name() but for the
402 * remote side.
403 *
404 * \sa local_name().
405 */
406 char *remote_name(int sockfd)
407 {
408 return __get_sock_name(sockfd, getpeername);
409 }
410
411 /**
412 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
413 * \param ss Container of IPv4/6 address
414 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
415 *
416 * \sa RFC 3493
417 */
418 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
419 {
420 struct in_addr ia = {.s_addr = 0};
421
422 if (ss->ss_family == AF_INET)
423 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
424 if (ss->ss_family == AF_INET6) {
425 const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
426
427 if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
428 memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
429 }
430 return ia;
431 }
432
433 /**
434 * Send a binary buffer.
435 *
436 * \param fd The file descriptor.
437 * \param buf The buffer to be sent.
438 * \param len The length of \a buf.
439 *
440 * Send out the buffer and try to resend the remaining part in case of short
441 * writes.
442 *
443 * \return Standard.
444 */
445 int send_bin_buffer(int fd, const char *buf, size_t len)
446 {
447 if (!len)
448 PARA_CRIT_LOG("len == 0\n");
449 return write_all(fd, buf, &len);
450 }
451
452 /**
453 * Send a \p NULL-terminated buffer.
454 *
455 * \param fd The file descriptor.
456 * \param buf The null-terminated buffer to be send.
457 *
458 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
459 *
460 * \return Standard.
461 */
462 int send_buffer(int fd, const char *buf)
463 {
464 return send_bin_buffer(fd, buf, strlen(buf));
465 }
466
467 /**
468 * Send a buffer given by a format string.
469 *
470 * \param fd The file descriptor.
471 * \param fmt A format string.
472 *
473 * \return Standard.
474 */
475 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
476 {
477 char *msg;
478 int ret;
479
480 PARA_VSPRINTF(fmt, msg);
481 ret = send_buffer(fd, msg);
482 free(msg);
483 return ret;
484 }
485
486 /**
487 * Receive data from a file descriptor.
488 *
489 * \param fd The file descriptor.
490 * \param buf The buffer to write the data to.
491 * \param size The size of \a buf.
492 *
493 * Receive at most \a size bytes from file descriptor \a fd.
494 *
495 * \return The number of bytes received on success, negative on errors, zero if
496 * the peer has performed an orderly shutdown.
497 *
498 * \sa recv(2).
499 */
500 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
501 {
502 ssize_t n;
503
504 n = recv(fd, buf, size, 0);
505 if (n == -1)
506 return -ERRNO_TO_PARA_ERROR(errno);
507 return n;
508 }
509
510 /**
511 * Receive and write terminating NULL byte.
512 *
513 * \param fd The file descriptor.
514 * \param buf The buffer to write the data to.
515 * \param size The size of \a buf.
516 *
517 * Read at most \a size - 1 bytes from file descriptor \a fd and
518 * write a NULL byte at the end of the received data.
519 *
520 * \return The return value of the underlying call to \a recv_bin_buffer().
521 *
522 * \sa recv_bin_buffer()
523 */
524 int recv_buffer(int fd, char *buf, size_t size)
525 {
526 int n;
527
528 assert(size);
529 n = recv_bin_buffer(fd, buf, size - 1);
530 if (n >= 0)
531 buf[n] = '\0';
532 else
533 *buf = '\0';
534 return n;
535 }
536
537 /**
538 * Wrapper around the accept system call.
539 *
540 * \param fd The listening socket.
541 * \param addr Structure which is filled in with the address of the peer socket.
542 * \param size Should contain the size of the structure pointed to by \a addr.
543 *
544 * Accept incoming connections on \a addr. Retry if interrupted.
545 *
546 * \return The new file descriptor on success, negative on errors.
547 *
548 * \sa accept(2).
549 */
550 int para_accept(int fd, void *addr, socklen_t size)
551 {
552 int new_fd;
553
554 do
555 new_fd = accept(fd, (struct sockaddr *) addr, &size);
556 while (new_fd < 0 && errno == EINTR);
557 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
558 }
559
560 /**
561 * Prepare a structure for \p AF_UNIX socket addresses.
562 *
563 * \param u Pointer to the struct to be prepared.
564 * \param name The socket pathname.
565 *
566 * This just copies \a name to the sun_path component of \a u.
567 *
568 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
569 * than \p UNIX_PATH_MAX.
570 */
571 static int init_unix_addr(struct sockaddr_un *u, const char *name)
572 {
573 if (strlen(name) >= UNIX_PATH_MAX)
574 return -E_NAME_TOO_LONG;
575 memset(u->sun_path, 0, UNIX_PATH_MAX);
576 u->sun_family = PF_UNIX;
577 strcpy(u->sun_path, name);
578 return 1;
579 }
580
581 /**
582 * Prepare, create, and bind a socket for local communication.
583 *
584 * \param name The socket pathname.
585 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
586 * \param mode The desired mode of the socket.
587 *
588 * This function creates a local socket for sequenced, reliable,
589 * two-way, connection-based byte streams.
590 *
591 * \return The file descriptor, on success, negative on errors.
592 *
593 * \sa socket(2)
594 * \sa bind(2)
595 * \sa chmod(2)
596 */
597 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
598 mode_t mode)
599 {
600 int fd, ret;
601
602 ret = init_unix_addr(unix_addr, name);
603 if (ret < 0)
604 return ret;
605 ret = socket(PF_UNIX, SOCK_STREAM, 0);
606 if (ret < 0)
607 return -ERRNO_TO_PARA_ERROR(errno);
608 fd = ret;
609 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
610 if (ret < 0) {
611 ret = -ERRNO_TO_PARA_ERROR(errno);
612 goto err;
613 }
614 ret = -E_CHMOD;
615 if (chmod(name, mode) < 0)
616 goto err;
617 return fd;
618 err:
619 close(fd);
620 return ret;
621 }
622
623 /**
624 * Prepare, create, and connect to a Unix domain socket for local communication.
625 *
626 * \param name The socket pathname.
627 *
628 * This function creates a local socket for sequenced, reliable, two-way,
629 * connection-based byte streams.
630 *
631 * \return The file descriptor, on success, negative on errors.
632 *
633 * \sa create_local_socket(), unix(7), connect(2).
634 */
635 int create_remote_socket(const char *name)
636 {
637 struct sockaddr_un unix_addr;
638 int fd, ret;
639
640 ret = init_unix_addr(&unix_addr, name);
641 if (ret < 0)
642 return ret;
643 fd = socket(PF_UNIX, SOCK_STREAM, 0);
644 if (fd < 0)
645 return -ERRNO_TO_PARA_ERROR(errno);
646 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
647 ret = -ERRNO_TO_PARA_ERROR(errno);
648 goto err;
649 }
650 return fd;
651 err:
652 close(fd);
653 return ret;
654 }
655
656 #ifndef HAVE_UCRED
657 ssize_t send_cred_buffer(int sock, char *buf)
658 {
659 return send_buffer(sock, buf);
660 }
661 int recv_cred_buffer(int fd, char *buf, size_t size)
662 {
663 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
664 }
665 #else /* HAVE_UCRED */
666 /**
667 * Send \p NULL-terminated buffer and Unix credentials of the current process.
668 *
669 * \param sock The socket file descriptor.
670 * \param buf The buffer to be sent.
671 *
672 * \return On success, this call returns the number of characters sent. On
673 * error, \p -E_SENDMSG is returned.
674 *
675 * \sa sendmsg(2), okir's Black Hats Manual.
676 */
677 ssize_t send_cred_buffer(int sock, char *buf)
678 {
679 char control[sizeof(struct cmsghdr) + sizeof(struct ucred)];
680 struct msghdr msg;
681 struct cmsghdr *cmsg;
682 static struct iovec iov;
683 struct ucred c;
684 int ret;
685
686 /* Response data */
687 iov.iov_base = buf;
688 iov.iov_len = strlen(buf);
689 c.pid = getpid();
690 c.uid = getuid();
691 c.gid = getgid();
692 /* compose the message */
693 memset(&msg, 0, sizeof(msg));
694 msg.msg_iov = &iov;
695 msg.msg_iovlen = 1;
696 msg.msg_control = control;
697 msg.msg_controllen = sizeof(control);
698 /* attach the ucred struct */
699 cmsg = CMSG_FIRSTHDR(&msg);
700 cmsg->cmsg_level = SOL_SOCKET;
701 cmsg->cmsg_type = SCM_CREDENTIALS;
702 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
703 *(struct ucred *)CMSG_DATA(cmsg) = c;
704 msg.msg_controllen = cmsg->cmsg_len;
705 ret = sendmsg(sock, &msg, 0);
706 if (ret < 0)
707 ret = -E_SENDMSG;
708 return ret;
709 }
710
711 static void dispose_fds(int *fds, unsigned num)
712 {
713 int i;
714
715 for (i = 0; i < num; i++)
716 close(fds[i]);
717 }
718
719 /**
720 * Receive a buffer and the Unix credentials of the sending process.
721 *
722 * \param fd the socket file descriptor.
723 * \param buf the buffer to store the message.
724 * \param size the size of \a buffer.
725 *
726 * \return negative on errors, the user id on success.
727 *
728 * \sa recvmsg(2), okir's Black Hats Manual.
729 */
730 int recv_cred_buffer(int fd, char *buf, size_t size)
731 {
732 char control[255];
733 struct msghdr msg;
734 struct cmsghdr *cmsg;
735 struct iovec iov;
736 int result = 0;
737 int yes = 1;
738 struct ucred cred;
739
740 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
741 memset(&msg, 0, sizeof(msg));
742 memset(buf, 0, size);
743 iov.iov_base = buf;
744 iov.iov_len = size;
745 msg.msg_iov = &iov;
746 msg.msg_iovlen = 1;
747 msg.msg_control = control;
748 msg.msg_controllen = sizeof(control);
749 if (recvmsg(fd, &msg, 0) < 0)
750 return -E_RECVMSG;
751 result = -E_SCM_CREDENTIALS;
752 cmsg = CMSG_FIRSTHDR(&msg);
753 while (cmsg) {
754 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
755 == SCM_CREDENTIALS) {
756 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
757 result = cred.uid;
758 } else
759 if (cmsg->cmsg_level == SOL_SOCKET
760 && cmsg->cmsg_type == SCM_RIGHTS) {
761 dispose_fds((int *) CMSG_DATA(cmsg),
762 (cmsg->cmsg_len - CMSG_LEN(0))
763 / sizeof(int));
764 }
765 cmsg = CMSG_NXTHDR(&msg, cmsg);
766 }
767 return result;
768 }
769 #endif /* HAVE_UCRED */
770
771 /**
772 * Receive a buffer and check for a pattern.
773 *
774 * \param fd The file descriptor to receive from.
775 * \param pattern The expected pattern.
776 * \param bufsize The size of the internal buffer.
777 *
778 * \return Positive if \a pattern was received, negative otherwise.
779 *
780 * This function tries to receive at most \a bufsize bytes from file descriptor
781 * \a fd. If at least \p strlen(\a pattern) bytes were received, the beginning
782 * of the received buffer is compared with \a pattern, ignoring case.
783 *
784 * \sa recv_buffer(), \sa strncasecmp(3).
785 */
786 int recv_pattern(int fd, const char *pattern, size_t bufsize)
787 {
788 size_t len = strlen(pattern);
789 char *buf = para_malloc(bufsize + 1);
790 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize + 1);
791
792 if (n < len)
793 goto out;
794 if (strncasecmp(buf, pattern, len))
795 goto out;
796 ret = 1;
797 out:
798 if (ret < 0) {
799 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n,
800 pattern);
801 if (n > 0)
802 PARA_NOTICE_LOG("recvd: %s\n", buf);
803 }
804 free(buf);
805 return ret;
806 }