audioc: Make all fds non-blocking.
[paraslash.git] / net.c
1 /*
2 * Copyright (C) 2005-2008 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 #include <netdb.h>
10
11 /* At least NetBSD needs these. */
12 #ifndef AI_V4MAPPED
13 #define AI_V4MAPPED 0
14 #endif
15 #ifndef AI_ALL
16 #define AI_ALL 0
17 #endif
18 #ifndef AI_ADDRCONFIG
19 #define AI_ADDRCONFIG 0
20 #endif
21
22 #include <dirent.h>
23
24 #include "para.h"
25 #include "error.h"
26 #include "net.h"
27 #include "string.h"
28 #include "fd.h"
29
30
31 /** Information about one encrypted connection. */
32 struct crypt_data {
33 /** Function used to decrypt received data. */
34 crypt_function *recv;
35 /** Function used to encrypt data to be sent. */
36 crypt_function *send;
37 /**
38 * Context-dependent data (crypt keys), passed verbatim to the above
39 * crypt functions.
40 */
41 void *private_data;
42 };
43 /** Array holding per fd crypt data. */
44 static struct crypt_data *crypt_data_array;
45 /** Current size of the crypt data array. */
46 static unsigned cda_size = 0;
47
48 /**
49 * Activate encryption for one file descriptor.
50 *
51 * \param fd The file descriptor.
52 * \param recv_f The function used for decrypting received data.
53 * \param send_f The function used for encrypting before sending.
54 * \param private_data User data supplied by the caller.
55 */
56 void enable_crypt(int fd, crypt_function *recv_f, crypt_function *send_f,
57 void *private_data)
58 {
59 if (fd + 1 > cda_size) {
60 crypt_data_array = para_realloc(crypt_data_array,
61 (fd + 1) * sizeof(struct crypt_data));
62 memset(crypt_data_array + cda_size, 0,
63 (fd + 1 - cda_size) * sizeof(struct crypt_data));
64 cda_size = fd + 1;
65 }
66 crypt_data_array[fd].recv = recv_f;
67 crypt_data_array[fd].send = send_f;
68 crypt_data_array[fd].private_data = private_data;
69 PARA_INFO_LOG("rc4 encryption activated for fd %d\n", fd);
70 }
71
72 /**
73 * Deactivate encryption for a given fd.
74 *
75 * \param fd The file descriptor.
76 *
77 * This must be called if and only if \p fd was activated via enable_crypt().
78 */
79 void disable_crypt(int fd)
80 {
81 if (cda_size < fd + 1)
82 return;
83 crypt_data_array[fd].recv = NULL;
84 crypt_data_array[fd].send = NULL;
85 crypt_data_array[fd].private_data = NULL;
86 }
87
88
89 /**
90 * Determine the socket type for a given layer-4 protocol.
91 *
92 * \param l4type The symbolic name of the transport-layer protocol.
93 *
94 * \sa ip(7), socket(2)
95 */
96 static inline int sock_type(const unsigned l4type)
97 {
98 switch (l4type) {
99 case IPPROTO_UDP: return SOCK_DGRAM;
100 case IPPROTO_TCP: return SOCK_STREAM;
101 case IPPROTO_DCCP: return SOCK_DCCP;
102 }
103 return -1; /* not supported here */
104 }
105
106 /**
107 * Pretty-print transport-layer name.
108 */
109 static const char *layer4_name(const unsigned l4type)
110 {
111 switch (l4type) {
112 case IPPROTO_UDP: return "UDP";
113 case IPPROTO_TCP: return "TCP";
114 case IPPROTO_DCCP: return "DCCP";
115 }
116 return "UNKNOWN PROTOCOL";
117 }
118
119 /**
120 * Resolve IPv4/IPv6 address and create a ready-to-use active or passive socket.
121 *
122 * \param l3type The layer-3 type (\p AF_INET, \p AF_INET6, \p AF_UNSPEC).
123 * \param l4type The layer-4 type (\p IPPROTO_xxx).
124 * \param passive Whether this is a passive (1) or active (0) socket.
125 * \param host Remote or local hostname or IPv/6 address string.
126 * \param port_number Decimal port number.
127 *
128 * This creates a ready-made IPv4/v6 socket structure after looking up the
129 * necessary parameters. The interpretation of \a host depends on the value of
130 * \a passive:
131 * - on a passive socket host is interpreted as an interface IPv4/6 address
132 * (can be left NULL);
133 * - on an active socket, \a host is the peer DNS name or IPv4/6 address
134 * to connect to;
135 * - \a port_number is in either case the numeric port number (not service
136 * string).
137 *
138 * Furthermore, bind(2) is called on passive sockets, and connect(2) on active
139 * sockets. The algorithm tries all possible address combinations until it
140 * succeeds.
141 *
142 * \return This function returns 1 on success and \a -E_ADDRESS_LOOKUP when no
143 * matching connection could be set up (with details in the error log).
144 *
145 * \sa ipv6(7), getaddrinfo(3), bind(2), connect(2).
146 */
147 int makesock(unsigned l3type, unsigned l4type, int passive,
148 const char *host, unsigned short port_number)
149 {
150 struct addrinfo *local = NULL, *src,
151 *remote = NULL, *dst, hints;
152 int rc, on = 1, sockfd = -1,
153 socktype = sock_type(l4type);
154 char port[6]; /* port number has at most 5 digits */
155
156 sprintf(port, "%u", port_number);
157 /* Set up address hint structure */
158 memset(&hints, 0, sizeof(hints));
159 hints.ai_family = l3type;
160 /* getaddrinfo does not really work well with SOCK_DCCP */
161 if (socktype == SOCK_DGRAM || socktype == SOCK_STREAM)
162 hints.ai_socktype = socktype;
163
164 /* only use addresses available on the host */
165 hints.ai_flags = AI_ADDRCONFIG;
166 if (l3type == AF_INET6)
167 /* use v4-mapped-v6 if no v6 addresses found */
168 hints.ai_flags |= AI_V4MAPPED | AI_ALL;
169
170 if (passive && host == NULL)
171 hints.ai_flags |= AI_PASSIVE;
172
173 /* Obtain local/remote address information */
174 if ((rc = getaddrinfo(host, port, &hints, passive ? &local : &remote))) {
175 PARA_ERROR_LOG("can not resolve %s address %s#%s: %s.\n",
176 layer4_name(l4type),
177 host? host : (passive? "[loopback]" : "[localhost]"),
178 port, gai_strerror(rc));
179 return -E_ADDRESS_LOOKUP;
180 }
181
182 /* Iterate over all src/dst combination, exhausting dst first */
183 for (src = local, dst = remote; src != NULL || dst != NULL; /* no op */ ) {
184 if (src && dst && src->ai_family == AF_INET
185 && dst->ai_family == AF_INET6)
186 goto get_next_dst; /* v4 -> v6 is not possible */
187
188 sockfd = socket(src ? src->ai_family : dst->ai_family,
189 socktype, l4type);
190 if (sockfd < 0)
191 goto get_next_dst;
192
193 /*
194 * Set those options that need to be set before establishing
195 * the connection. Reuse the address on passive (listening)
196 * sockets to avoid failure on restart.
197 */
198 if (passive && setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR,
199 &on, sizeof(on)) == -1) {
200 PARA_ERROR_LOG("can not set SO_REUSEADDR: %s\n",
201 strerror(errno));
202 return -ERRNO_TO_PARA_ERROR(errno);
203 }
204
205 if (src) {
206 if (bind(sockfd, src->ai_addr, src->ai_addrlen) < 0) {
207 close(sockfd);
208 goto get_next_src;
209 }
210 if (!dst) /* bind-only completed successfully */
211 break;
212 }
213
214 if (dst && connect(sockfd, dst->ai_addr, dst->ai_addrlen) == 0)
215 break; /* connection completed successfully */
216 close(sockfd);
217 get_next_dst:
218 if (dst && (dst = dst->ai_next))
219 continue;
220 get_next_src:
221 if (src && (src = src->ai_next)) /* restart inner loop */
222 dst = remote;
223 }
224 if (local)
225 freeaddrinfo(local);
226 if (remote)
227 freeaddrinfo(remote);
228
229 if (src == NULL && dst == NULL) {
230 PARA_ERROR_LOG("can not create %s socket %s#%s.\n",
231 layer4_name(l4type), host? host : (passive?
232 "[loopback]" : "[localhost]"), port);
233 return -ERRNO_TO_PARA_ERROR(errno);
234 }
235 return sockfd;
236 }
237
238 /**
239 * Create a passive / listening socket.
240 *
241 * \param l3type The network-layer type (\p AF_xxx).
242 * \param l4type The transport-layer type (\p IPPROTO_xxx).
243 * \param port The decimal port number to listen on.
244 *
245 * \return Positive integer (socket descriptor) on success, negative value
246 * otherwise.
247 *
248 * \sa makesock(), ip(7), ipv6(7), bind(2), listen(2).
249 */
250 int para_listen(unsigned l3type, unsigned l4type, unsigned short port)
251 {
252 int ret, fd = makesock(l3type, l4type, 1, NULL, port);
253
254 if (fd > 0) {
255 ret = listen(fd, BACKLOG);
256 if (ret < 0) {
257 close(fd);
258 return -ERRNO_TO_PARA_ERROR(errno);
259 }
260 PARA_INFO_LOG("listening on %s port %u, fd %d\n",
261 layer4_name(l4type), port, fd);
262 }
263 return fd;
264 }
265
266 /**
267 * Print numeric host and port number (beware - uses static char).
268 *
269 * \param sa The IPv4/IPv6 socket address to use.
270 * \param len The length of \p sa.
271 *
272 * \sa getnameinfo(3).
273 */
274 static char *host_and_port(struct sockaddr *sa, socklen_t len)
275 {
276 static char output[NI_MAXHOST + NI_MAXSERV + 2];
277 char hbuf[NI_MAXHOST], sbuf[NI_MAXSERV];
278 int ret;
279
280 ret = getnameinfo(sa, len, hbuf, sizeof(hbuf), sbuf, sizeof(sbuf),
281 NI_NUMERICHOST | NI_NUMERICSERV);
282 if (ret) {
283 PARA_WARNING_LOG("hostname lookup error (%s).\n",
284 gai_strerror(ret));
285 sprintf(output, "(unknown)");
286 } else
287 sprintf(output, "%s#%s", hbuf, sbuf);
288 return output;
289 }
290
291 /**
292 * Look up the local or remote side of a connected socket structure.
293 *
294 * \param fd The socket descriptor of the connected socket.
295 * \param getname Either \p getsockname() for local, or \p getpeername() for
296 * remote side.
297 *
298 * \return A static character string identifying hostname and port of the
299 * chosen side.
300 *
301 * \sa getsockname(2), getpeername(2).
302 */
303 static char *__get_sock_name(int fd, int (*getname)(int, struct sockaddr*,
304 socklen_t *))
305 {
306 struct sockaddr_storage ss;
307 socklen_t sslen = sizeof(ss);
308
309 if (getname(fd, (struct sockaddr *)&ss, &sslen) < 0) {
310 static char *dont_know = "(don't know)";
311 PARA_ERROR_LOG("can not determine address from fd %d: %s\n",
312 fd, strerror(errno));
313 return dont_know;
314 }
315 return host_and_port((struct sockaddr *)&ss, sslen);
316 }
317
318 char *local_name(int sockfd)
319 {
320 return __get_sock_name(sockfd, getsockname);
321 }
322
323 char *remote_name(int sockfd)
324 {
325 return __get_sock_name(sockfd, getpeername);
326 }
327
328 /**
329 * Extract IPv4 or IPv6-mapped-IPv4 address from sockaddr_storage.
330 * \param ss Container of IPv4/6 address
331 * \return Extracted IPv4 address (different from 0) or 0 if unsuccessful.
332 *
333 * \sa RFC 3493
334 */
335 struct in_addr extract_v4_addr(const struct sockaddr_storage *ss)
336 {
337 struct in_addr ia = {.s_addr = 0};
338
339 if (ss->ss_family == AF_INET)
340 ia.s_addr = ((struct sockaddr_in *)ss)->sin_addr.s_addr;
341 if (ss->ss_family == AF_INET6) {
342 const struct in6_addr v6_addr = ((struct sockaddr_in6 *)ss)->sin6_addr;
343
344 if (IN6_IS_ADDR_V4MAPPED(&v6_addr))
345 memcpy(&ia.s_addr, &(v6_addr.s6_addr[12]), 4);
346 }
347 return ia;
348 }
349
350 /**
351 * Encrypt and send a binary buffer.
352 *
353 * \param fd The file descriptor.
354 * \param buf The buffer to be encrypted and sent.
355 * \param len The length of \a buf.
356 *
357 * Check if encryption is available. If yes, encrypt the given buffer. Send
358 * out the buffer, encrypted or not, and try to resend the remaing part in case
359 * of short writes.
360 *
361 * \return Standard.
362 */
363 int send_bin_buffer(int fd, const char *buf, size_t len)
364 {
365 int ret;
366 crypt_function *cf = NULL;
367
368 if (!len)
369 PARA_CRIT_LOG("len == 0\n");
370 if (fd + 1 <= cda_size)
371 cf = crypt_data_array[fd].send;
372 if (cf) {
373 void *private = crypt_data_array[fd].private_data;
374 /* RC4 may write more than len to the output buffer */
375 unsigned char *outbuf = para_malloc(ROUND_UP(len, 8));
376 (*cf)(len, (unsigned char *)buf, outbuf, private);
377 ret = write_all(fd, (char *)outbuf, &len);
378 free(outbuf);
379 } else
380 ret = write_all(fd, buf, &len);
381 return ret;
382 }
383
384 /**
385 * Encrypt and send null terminated buffer.
386 *
387 * \param fd The file descriptor.
388 * \param buf The null-terminated buffer to be send.
389 *
390 * This is equivalent to send_bin_buffer(fd, buf, strlen(buf)).
391 *
392 * \return Standard.
393 */
394 int send_buffer(int fd, const char *buf)
395 {
396 return send_bin_buffer(fd, buf, strlen(buf));
397 }
398
399
400 /**
401 * Send and encrypt a buffer given by a format string.
402 *
403 * \param fd The file descriptor.
404 * \param fmt A format string.
405 *
406 * \return Standard.
407 */
408 __printf_2_3 int send_va_buffer(int fd, const char *fmt, ...)
409 {
410 char *msg;
411 int ret;
412
413 PARA_VSPRINTF(fmt, msg);
414 ret = send_buffer(fd, msg);
415 free(msg);
416 return ret;
417 }
418
419 /**
420 * Receive and decrypt.
421 *
422 * \param fd The file descriptor.
423 * \param buf The buffer to write the decrypted data to.
424 * \param size The size of \a buf.
425 *
426 * Receive at most \a size bytes from file descriptor \a fd. If encryption is
427 * available, decrypt the received buffer.
428 *
429 * \return The number of bytes received on success, negative on errors.
430 *
431 * \sa recv(2)
432 */
433 __must_check int recv_bin_buffer(int fd, char *buf, size_t size)
434 {
435 ssize_t n;
436 crypt_function *cf = NULL;
437
438 if (fd + 1 <= cda_size)
439 cf = crypt_data_array[fd].recv;
440 if (cf) {
441 unsigned char *tmp = para_malloc(size);
442 void *private = crypt_data_array[fd].private_data;
443 n = recv(fd, tmp, size, 0);
444 if (n > 0) {
445 size_t numbytes = n;
446 unsigned char *b = (unsigned char *)buf;
447 (*cf)(numbytes, tmp, b, private);
448 }
449 free(tmp);
450 } else
451 n = recv(fd, buf, size, 0);
452 if (n == -1)
453 return -ERRNO_TO_PARA_ERROR(errno);
454 return n;
455 }
456
457 /**
458 * Receive, decrypt and write terminating NULL byte.
459 *
460 * \param fd The file descriptor.
461 * \param buf The buffer to write the decrypted data to.
462 * \param size The size of \a buf.
463 *
464 * Read and decrypt at most \a size - 1 bytes from file descriptor \a fd and
465 * write a NULL byte at the end of the received data.
466 *
467 * \return The return value of the underlying call to \a recv_bin_buffer().
468 *
469 * \sa recv_bin_buffer()
470 */
471 int recv_buffer(int fd, char *buf, size_t size)
472 {
473 int n;
474
475 assert(size);
476 n = recv_bin_buffer(fd, buf, size - 1);
477 if (n >= 0)
478 buf[n] = '\0';
479 else
480 *buf = '\0';
481 return n;
482 }
483
484 /**
485 * Wrapper around the accept system call.
486 *
487 * \param fd The listening socket.
488 * \param addr Structure which is filled in with the address of the peer socket.
489 * \param size Should contain the size of the structure pointed to by \a addr.
490 *
491 * Accept incoming connections on \a addr. Retry if interrupted.
492 *
493 * \return The new file descriptor on success, negative on errors.
494 *
495 * \sa accept(2).
496 */
497 int para_accept(int fd, void *addr, socklen_t size)
498 {
499 int new_fd;
500
501 do
502 new_fd = accept(fd, (struct sockaddr *) addr, &size);
503 while (new_fd < 0 && errno == EINTR);
504 return new_fd < 0? -ERRNO_TO_PARA_ERROR(errno) : new_fd;
505 }
506
507 /**
508 * Prepare a structure for \p AF_UNIX socket addresses.
509 *
510 * \param u Pointer to the struct to be prepared.
511 * \param name The socket pathname.
512 *
513 * This just copies \a name to the sun_path component of \a u.
514 *
515 * \return Positive on success, \p -E_NAME_TOO_LONG if \a name is longer
516 * than \p UNIX_PATH_MAX.
517 */
518 static int init_unix_addr(struct sockaddr_un *u, const char *name)
519 {
520 if (strlen(name) >= UNIX_PATH_MAX)
521 return -E_NAME_TOO_LONG;
522 memset(u->sun_path, 0, UNIX_PATH_MAX);
523 u->sun_family = PF_UNIX;
524 strcpy(u->sun_path, name);
525 return 1;
526 }
527
528 /**
529 * Prepare, create, and bind a socket for local communication.
530 *
531 * \param name The socket pathname.
532 * \param unix_addr Pointer to the \p AF_UNIX socket structure.
533 * \param mode The desired mode of the socket.
534 *
535 * This function creates a local socket for sequenced, reliable,
536 * two-way, connection-based byte streams.
537 *
538 * \return The file descriptor, on success, negative on errors.
539 *
540 * \sa socket(2)
541 * \sa bind(2)
542 * \sa chmod(2)
543 */
544 int create_local_socket(const char *name, struct sockaddr_un *unix_addr,
545 mode_t mode)
546 {
547 int fd, ret;
548
549 ret = init_unix_addr(unix_addr, name);
550 if (ret < 0)
551 return ret;
552 ret = socket(PF_UNIX, SOCK_STREAM, 0);
553 if (ret < 0)
554 return -ERRNO_TO_PARA_ERROR(errno);
555 fd = ret;
556 ret = bind(fd, (struct sockaddr *) unix_addr, UNIX_PATH_MAX);
557 if (ret < 0) {
558 ret = -ERRNO_TO_PARA_ERROR(errno);
559 goto err;
560 }
561 ret = -E_CHMOD;
562 if (chmod(name, mode) < 0)
563 goto err;
564 return fd;
565 err:
566 close(fd);
567 return ret;
568 }
569
570 /**
571 * Prepare, create, and connect to a Unix domain socket for local communication.
572 *
573 * \param name The socket pathname.
574 *
575 * This function creates a local socket for sequenced, reliable, two-way,
576 * connection-based byte streams.
577 *
578 * \return The file descriptor, on success, negative on errors.
579 *
580 * \sa create_local_socket(), unix(7), connect(2).
581 */
582 int create_remote_socket(const char *name)
583 {
584 struct sockaddr_un unix_addr;
585 int fd, ret;
586
587 ret = init_unix_addr(&unix_addr, name);
588 if (ret < 0)
589 return ret;
590 fd = socket(PF_UNIX, SOCK_STREAM, 0);
591 if (fd < 0)
592 return -ERRNO_TO_PARA_ERROR(errno);
593 if (connect(fd, (struct sockaddr *)&unix_addr, sizeof(unix_addr)) == -1) {
594 ret = -ERRNO_TO_PARA_ERROR(errno);
595 goto err;
596 }
597 return fd;
598 err:
599 close(fd);
600 return ret;
601 }
602
603 #ifndef HAVE_UCRED
604 ssize_t send_cred_buffer(int sock, char *buf)
605 {
606 return send_buffer(sock, buf);
607 }
608 int recv_cred_buffer(int fd, char *buf, size_t size)
609 {
610 return recv_buffer(fd, buf, size) > 0? 1 : -E_RECVMSG;
611 }
612 #else /* HAVE_UCRED */
613 /**
614 * Send \p NULL-terminated buffer and Unix credentials of the current process.
615 *
616 * \param sock The socket file descriptor.
617 * \param buf The buffer to be sent.
618 *
619 * \return On success, this call returns the number of characters sent. On
620 * error, \p -E_SENDMSG is returned.
621 *
622 * \sa sendmsg(2), okir's Black Hats Manual.
623 */
624 ssize_t send_cred_buffer(int sock, char *buf)
625 {
626 char control[sizeof(struct cmsghdr) + 10];
627 struct msghdr msg;
628 struct cmsghdr *cmsg;
629 static struct iovec iov;
630 struct ucred c;
631 int ret;
632
633 /* Response data */
634 iov.iov_base = buf;
635 iov.iov_len = strlen(buf);
636 c.pid = getpid();
637 c.uid = getuid();
638 c.gid = getgid();
639 /* compose the message */
640 memset(&msg, 0, sizeof(msg));
641 msg.msg_iov = &iov;
642 msg.msg_iovlen = 1;
643 msg.msg_control = control;
644 msg.msg_controllen = sizeof(control);
645 /* attach the ucred struct */
646 cmsg = CMSG_FIRSTHDR(&msg);
647 cmsg->cmsg_level = SOL_SOCKET;
648 cmsg->cmsg_type = SCM_CREDENTIALS;
649 cmsg->cmsg_len = CMSG_LEN(sizeof(struct ucred));
650 *(struct ucred *)CMSG_DATA(cmsg) = c;
651 msg.msg_controllen = cmsg->cmsg_len;
652 ret = sendmsg(sock, &msg, 0);
653 if (ret < 0)
654 ret = -E_SENDMSG;
655 return ret;
656 }
657
658 static void dispose_fds(int *fds, unsigned num)
659 {
660 int i;
661
662 for (i = 0; i < num; i++)
663 close(fds[i]);
664 }
665
666 /**
667 * Receive a buffer and the Unix credentials of the sending process.
668 *
669 * \param fd the socket file descriptor.
670 * \param buf the buffer to store the message.
671 * \param size the size of \a buffer.
672 *
673 * \return negative on errors, the user id on success.
674 *
675 * \sa recvmsg(2), okir's Black Hats Manual.
676 */
677 int recv_cred_buffer(int fd, char *buf, size_t size)
678 {
679 char control[255];
680 struct msghdr msg;
681 struct cmsghdr *cmsg;
682 struct iovec iov;
683 int result = 0;
684 int yes = 1;
685 struct ucred cred;
686
687 setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &yes, sizeof(int));
688 memset(&msg, 0, sizeof(msg));
689 memset(buf, 0, size);
690 iov.iov_base = buf;
691 iov.iov_len = size;
692 msg.msg_iov = &iov;
693 msg.msg_iovlen = 1;
694 msg.msg_control = control;
695 msg.msg_controllen = sizeof(control);
696 if (recvmsg(fd, &msg, 0) < 0)
697 return -E_RECVMSG;
698 result = -E_SCM_CREDENTIALS;
699 cmsg = CMSG_FIRSTHDR(&msg);
700 while (cmsg) {
701 if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type
702 == SCM_CREDENTIALS) {
703 memcpy(&cred, CMSG_DATA(cmsg), sizeof(struct ucred));
704 result = cred.uid;
705 } else
706 if (cmsg->cmsg_level == SOL_SOCKET
707 && cmsg->cmsg_type == SCM_RIGHTS) {
708 dispose_fds((int *) CMSG_DATA(cmsg),
709 (cmsg->cmsg_len - CMSG_LEN(0))
710 / sizeof(int));
711 }
712 cmsg = CMSG_NXTHDR(&msg, cmsg);
713 }
714 return result;
715 }
716 #endif /* HAVE_UCRED */
717
718 /**
719 * Receive a buffer and check for a pattern.
720 *
721 * \param fd The file descriptor to receive from.
722 * \param pattern The expected pattern.
723 * \param bufsize The size of the internal buffer.
724 *
725 * \return Positive if \a pattern was received, negative otherwise.
726 *
727 * This function creates a buffer of size \a bufsize and tries
728 * to receive at most \a bufsize bytes from file descriptor \a fd.
729 * If at least \p strlen(\a pattern) bytes were received, the beginning of
730 * the received buffer is compared with \a pattern, ignoring case.
731 *
732 * \sa recv_buffer(), \sa strncasecmp(3).
733 */
734 int recv_pattern(int fd, const char *pattern, size_t bufsize)
735 {
736 size_t len = strlen(pattern);
737 char *buf = para_malloc(bufsize + 1);
738 int ret = -E_RECV_PATTERN, n = recv_buffer(fd, buf, bufsize);
739
740 if (n < len)
741 goto out;
742 if (strncasecmp(buf, pattern, len))
743 goto out;
744 ret = 1;
745 out:
746 if (ret < 0) {
747 PARA_NOTICE_LOG("n = %d, did not receive pattern '%s'\n", n,
748 pattern);
749 if (n > 0)
750 PARA_NOTICE_LOG("recvd: %s\n", buf);
751 }
752 free(buf);
753 return ret;
754 }