1 /* $OpenBSD: tftpd.c,v 1.40 2005/03/10 10:22:32 claudio Exp $ */
2
3 /*
4 * Copyright (c) 1983 Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33
34 __COPYRIGHT("@(#) Copyright (c) 1983 Regents of the University of California.\n\
35 All rights reserved.\n");
36 __SCCSID("@(#)tftpd.c 5.13 (Berkeley) 2/26/91");
37 __RCSID("$MirOS: src/libexec/tftpd/tftpd.c,v 1.2 2012/09/02 21:06:54 tg Exp $");
38
39 /*
40 * Trivial file transfer protocol server.
41 *
42 * This version includes many modifications by Jim Guyton <guyton@rand-unix>
43 */
44
45 #include <sys/types.h>
46 #include <sys/ioctl.h>
47 #include <sys/stat.h>
48 #include <sys/uio.h>
49 #include <signal.h>
50 #include <unistd.h>
51 #include <stdlib.h>
52 #include <fcntl.h>
53
54 #include <sys/socket.h>
55 #include <netinet/in.h>
56 #include <arpa/tftp.h>
57 #include <netdb.h>
58
59 #include <setjmp.h>
60 #include <syslog.h>
61 #include <stdio.h>
62 #include <errno.h>
63 #include <ctype.h>
64 #include <string.h>
65 #include <stdlib.h>
66 #include <pwd.h>
67
68 #define TIMEOUT 5
69 #define MAX_TIMEOUTS 5
70
71 extern char *__progname;
72 struct sockaddr_storage s_in;
73 int peer;
74 int rexmtval = TIMEOUT;
75 int max_rexmtval = 2*TIMEOUT;
76
77 #define PKTSIZE SEGSIZE+4
78 char buf[PKTSIZE];
79 char ackbuf[PKTSIZE];
80 struct sockaddr_storage from;
81
82 int ndirs;
83 char **dirs;
84
85 int secure;
86 int cancreate;
87
88 struct formats;
89 int validate_access(char *filename, int mode);
90 int recvfile(struct formats *pf);
91 int sendfile(struct formats *pf);
92
93 struct formats {
94 const char *f_mode;
95 int (*f_validate)(char *, int);
96 int (*f_send)(struct formats *);
97 int (*f_recv)(struct formats *);
98 int f_convert;
99 } formats[] = {
100 { "netascii", validate_access, sendfile, recvfile, 1 },
101 { "octet", validate_access, sendfile, recvfile, 0 },
102 { NULL, NULL, NULL, NULL, 0 }
103 };
104 struct options {
105 const char *o_type;
106 char *o_request;
107 int o_reply; /* turn into union if need be */
108 } options[] = {
109 { "tsize", NULL, 0 }, /* OPT_TSIZE */
110 { "timeout", NULL, 0 }, /* OPT_TIMEOUT */
111 { NULL, NULL, 0 }
112 };
113 enum opt_enum {
114 OPT_TSIZE = 0,
115 OPT_TIMEOUT
116 };
117
118 int validate_access(char *filename, int mode);
119 void tftp(struct tftphdr *tp, int size);
120 void nak(int error);
121 void oack(void);
122
123 int readit(FILE *file, struct tftphdr **dpp, int convert);
124 void read_ahead(FILE *file, int convert);
125 int writeit(FILE *file, struct tftphdr **dpp, int ct, int convert);
126 int write_behind(FILE *file, int convert);
127 int synchnet(int f);
128
129 static void
usage(void)130 usage(void)
131 {
132 syslog(LOG_ERR, "Usage: %s [-cs] [directory ...]", __progname);
133 exit(1);
134 }
135
136 int
main(int argc,char * argv[])137 main(int argc, char *argv[])
138 {
139 int n = 0, on = 1, fd = 0, i, c;
140 struct tftphdr *tp;
141 struct passwd *pw;
142 char cbuf[CMSG_SPACE(sizeof(struct sockaddr_storage))];
143 struct cmsghdr *cmsg;
144 struct msghdr msg;
145 struct iovec iov;
146 pid_t pid = 0;
147 socklen_t j;
148
149 openlog(__progname, LOG_PID | LOG_NDELAY, LOG_DAEMON);
150
151 while ((c = getopt(argc, argv, "cs")) != -1)
152 switch (c) {
153 case 'c':
154 cancreate = 1;
155 break;
156 case 's':
157 secure = 1;
158 break;
159 default:
160 usage();
161 break;
162 }
163
164 for (; optind != argc; optind++) {
165 char **d;
166
167 d = realloc(dirs, (ndirs+2) * sizeof (char *));
168 if (d == NULL) {
169 syslog(LOG_ERR, "malloc: %m");
170 exit(1);
171 }
172 dirs = d;
173 dirs[n++] = argv[optind];
174 dirs[n] = NULL;
175 ndirs++;
176 }
177
178 pw = getpwnam("_tftpd");
179 if (!pw) {
180 syslog(LOG_ERR, "no _tftpd: %m");
181 exit(1);
182 }
183
184 if (secure) {
185 if (ndirs == 0) {
186 syslog(LOG_ERR, "no -s directory");
187 exit(1);
188 }
189 if (ndirs > 1) {
190 syslog(LOG_ERR, "too many -s directories");
191 exit(1);
192 }
193 tzset();
194 if (chroot(dirs[0])) {
195 syslog(LOG_ERR, "chroot %s: %m", dirs[0]);
196 exit(1);
197 }
198 if (chdir("/")) {
199 syslog(LOG_ERR, "chdir: %m");
200 exit(1);
201 }
202 }
203
204 setegid(pw->pw_gid);
205 setgid(pw->pw_gid);
206 seteuid(pw->pw_uid);
207 setuid(pw->pw_uid);
208
209 if (ioctl(fd, FIONBIO, &on) < 0) {
210 syslog(LOG_ERR, "ioctl(FIONBIO): %m");
211 exit(1);
212 }
213
214 j = sizeof(s_in);
215 if (getsockname(fd, (struct sockaddr *)&s_in, &j) == -1) {
216 syslog(LOG_ERR, "getsockname: %m");
217 exit(1);
218 }
219
220 switch (s_in.ss_family) {
221 case AF_INET:
222 if (setsockopt(fd, IPPROTO_IP, IP_RECVDSTADDR, &on,
223 sizeof(on)) == -1) {
224 syslog(LOG_ERR, "setsockopt(IP_RECVDSTADDR): %m");
225 exit (1);
226 }
227 break;
228 case AF_INET6:
229 if (setsockopt(fd, IPPROTO_IPV6, IPV6_RECVDSTADDR, &on,
230 sizeof(on)) == -1) {
231 syslog(LOG_ERR, "setsockopt(IPV6_RECVDSTADDR): %m");
232 exit (1);
233 }
234 break;
235 }
236
237 bzero(&msg, sizeof(msg));
238 iov.iov_base = buf;
239 iov.iov_len = sizeof(buf);
240 msg.msg_name = &from;
241 msg.msg_namelen = sizeof(from);
242 msg.msg_iov = &iov;
243 msg.msg_iovlen = 1;
244 msg.msg_control = cbuf;
245 msg.msg_controllen = CMSG_LEN(sizeof(struct sockaddr_storage));
246
247 n = recvmsg(fd, &msg, 0);
248 if (n < 0) {
249 syslog(LOG_ERR, "recvmsg: %m");
250 exit(1);
251 }
252
253 /*
254 * Now that we have read the message out of the UDP
255 * socket, we fork and exit. Thus, inetd will go back
256 * to listening to the tftp port, and the next request
257 * to come in will start up a new instance of tftpd.
258 *
259 * We do this so that inetd can run tftpd in "wait" mode.
260 * The problem with tftpd running in "nowait" mode is that
261 * inetd may get one or more successful "selects" on the
262 * tftp port before we do our receive, so more than one
263 * instance of tftpd may be started up. Worse, if tftpd
264 * breaks before doing the above "recvfrom", inetd would
265 * spawn endless instances, clogging the system.
266 */
267 for (i = 1; i < 20; i++) {
268 pid = fork();
269 if (pid < 0) {
270 sleep(i);
271 /*
272 * flush out to most recently sent request.
273 *
274 * This may drop some requests, but those
275 * will be resent by the clients when
276 * they timeout. The positive effect of
277 * this flush is to (try to) prevent more
278 * than one tftpd being started up to service
279 * a single request from a single client.
280 */
281 bzero(&msg, sizeof(msg));
282 iov.iov_base = buf;
283 iov.iov_len = sizeof(buf);
284 msg.msg_name = &from;
285 msg.msg_namelen = sizeof(from);
286 msg.msg_iov = &iov;
287 msg.msg_iovlen = 1;
288 msg.msg_control = cbuf;
289 msg.msg_controllen =
290 CMSG_LEN(sizeof(struct sockaddr_storage));
291
292 i = recvmsg(fd, &msg, 0);
293 if (i > 0) {
294 n = i;
295 }
296 } else
297 break;
298 }
299 if (pid < 0) {
300 syslog(LOG_ERR, "fork: %m");
301 exit(1);
302 } else if (pid != 0)
303 exit(0);
304
305 alarm(0);
306 close(fd);
307 close(1);
308 peer = socket(from.ss_family, SOCK_DGRAM, 0);
309 if (peer < 0) {
310 syslog(LOG_ERR, "socket: %m");
311 exit(1);
312 }
313 memset(&s_in, 0, sizeof(s_in));
314 s_in.ss_family = from.ss_family;
315 s_in.ss_len = from.ss_len;
316
317 /* get local address if possible */
318 for (cmsg = CMSG_FIRSTHDR(&msg); cmsg != NULL;
319 cmsg = CMSG_NXTHDR(&msg, cmsg)) {
320 if (cmsg->cmsg_level == IPPROTO_IP &&
321 cmsg->cmsg_type == IP_RECVDSTADDR) {
322 memcpy(&((struct sockaddr_in *)&s_in)->sin_addr,
323 CMSG_DATA(cmsg), sizeof(struct in_addr));
324 break;
325 }
326 if (cmsg->cmsg_level == IPPROTO_IPV6 &&
327 cmsg->cmsg_type == IPV6_RECVDSTADDR) {
328 memcpy(&((struct sockaddr_in6 *)&s_in)->sin6_addr,
329 CMSG_DATA(cmsg), sizeof(struct in6_addr));
330 break;
331 }
332 }
333
334 if (bind(peer, (struct sockaddr *)&s_in, s_in.ss_len) < 0) {
335 syslog(LOG_ERR, "bind: %m");
336 exit(1);
337 }
338 if (connect(peer, (struct sockaddr *)&from, from.ss_len) < 0) {
339 syslog(LOG_ERR, "connect: %m");
340 exit(1);
341 }
342 tp = (struct tftphdr *)buf;
343 tp->th_opcode = ntohs(tp->th_opcode);
344 if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
345 tftp(tp, n);
346 exit(1);
347 }
348
349 /*
350 * Handle initial connection protocol.
351 */
352 void
tftp(struct tftphdr * tp,int size)353 tftp(struct tftphdr *tp, int size)
354 {
355 char *cp;
356 int i, first = 1, has_options = 0, ecode;
357 struct formats *pf;
358 char *filename, *mode = NULL, *option, *ccp;
359 char fnbuf[MAXPATHLEN];
360
361 cp = tp->th_stuff;
362 again:
363 while (cp < buf + size) {
364 if (*cp == '\0')
365 break;
366 cp++;
367 }
368 if (*cp != '\0') {
369 nak(EBADOP);
370 exit(1);
371 }
372 i = cp - tp->th_stuff;
373 if (i >= sizeof(fnbuf)) {
374 nak(EBADOP);
375 exit(1);
376 }
377 memcpy(fnbuf, tp->th_stuff, i);
378 fnbuf[i] = '\0';
379 filename = fnbuf;
380 if (first) {
381 mode = ++cp;
382 first = 0;
383 goto again;
384 }
385 for (cp = mode; *cp; cp++)
386 if (isupper(*cp))
387 *cp = tolower(*cp);
388 for (pf = formats; pf->f_mode; pf++)
389 if (strcmp(pf->f_mode, mode) == 0)
390 break;
391 if (pf->f_mode == 0) {
392 nak(EBADOP);
393 exit(1);
394 }
395 while (++cp < buf + size) {
396 for (i = 2, ccp = cp; i > 0; ccp++) {
397 if (ccp >= buf + size) {
398 /*
399 * Don't reject the request, just stop trying
400 * to parse the option and get on with it.
401 * Some Apple OpenFirmware versions have
402 * trailing garbage on the end of otherwise
403 * valid requests.
404 */
405 goto option_fail;
406 } else if (*ccp == '\0')
407 i--;
408 }
409 for (option = cp; *cp; cp++)
410 if (isupper(*cp))
411 *cp = tolower(*cp);
412 for (i = 0; options[i].o_type != NULL; i++)
413 if (strcmp(option, options[i].o_type) == 0) {
414 options[i].o_request = ++cp;
415 has_options = 1;
416 }
417 cp = ccp-1;
418 }
419
420 option_fail:
421 if (options[OPT_TIMEOUT].o_request) {
422 int to = atoi(options[OPT_TIMEOUT].o_request);
423 if (to < 1 || to > 255) {
424 nak(EBADOP);
425 exit(1);
426 }
427 else if (to <= max_rexmtval)
428 options[OPT_TIMEOUT].o_reply = rexmtval = to;
429 else
430 options[OPT_TIMEOUT].o_request = NULL;
431 }
432
433 ecode = (*pf->f_validate)(filename, tp->th_opcode);
434 if (has_options)
435 oack();
436 if (ecode) {
437 nak(ecode);
438 exit(1);
439 }
440 if (tp->th_opcode == WRQ)
441 (*pf->f_recv)(pf);
442 else
443 (*pf->f_send)(pf);
444 exit(0);
445 }
446
447
448 FILE *file;
449
450 /*
451 * Validate file access. Since we
452 * have no uid or gid, for now require
453 * file to exist and be publicly
454 * readable/writable.
455 * If we were invoked with arguments
456 * from inetd then the file must also be
457 * in one of the given directory prefixes.
458 * Note also, full path name must be
459 * given as we have no login directory.
460 */
461 int
validate_access(char * filename,int mode)462 validate_access(char *filename, int mode)
463 {
464 struct stat stbuf;
465 char *cp, **dirp;
466 int fd, wmode;
467
468 if (!secure) {
469 if (*filename != '/')
470 return (EACCESS);
471 /*
472 * prevent tricksters from getting around the directory
473 * restrictions
474 */
475 for (cp = filename + 1; *cp; cp++)
476 if (*cp == '.' && strncmp(cp-1, "/../", 4) == 0)
477 return(EACCESS);
478 for (dirp = dirs; *dirp; dirp++)
479 if (strncmp(filename, *dirp, strlen(*dirp)) == 0)
480 break;
481 if (*dirp==0 && dirp!=dirs)
482 return (EACCESS);
483 }
484
485 /*
486 * We use a different permissions scheme if `cancreate' is
487 * set.
488 */
489 wmode = O_TRUNC;
490 if (stat(filename, &stbuf) < 0) {
491 if (!cancreate)
492 return (errno == ENOENT ? ENOTFOUND : EACCESS);
493 else {
494 if ((errno == ENOENT) && (mode != RRQ))
495 wmode |= O_CREAT;
496 else
497 return(EACCESS);
498 }
499 } else {
500 if (mode == RRQ) {
501 if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
502 return (EACCESS);
503 } else {
504 if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
505 return (EACCESS);
506 }
507 }
508 if (options[OPT_TSIZE].o_request) {
509 if (mode == RRQ)
510 options[OPT_TSIZE].o_reply = stbuf.st_size;
511 else
512 /* XXX Allows writes of all sizes. */
513 options[OPT_TSIZE].o_reply =
514 atoi(options[OPT_TSIZE].o_request);
515 }
516 fd = open(filename, mode == RRQ ? O_RDONLY : (O_WRONLY|wmode), 0666);
517 if (fd < 0)
518 return (errno + 100);
519 /*
520 * If the file was created, set default permissions.
521 */
522 if ((wmode & O_CREAT) && fchmod(fd, 0666) < 0) {
523 int serrno = errno;
524
525 close(fd);
526 unlink(filename);
527
528 return (serrno + 100);
529 }
530 file = fdopen(fd, (mode == RRQ)? "r":"w");
531 if (file == NULL) {
532 close(fd);
533 return (errno + 100);
534 }
535 return (0);
536 }
537
538 int timeouts;
539 jmp_buf timeoutbuf;
540
541 /* ARGSUSED */
542 static void
timer(int signo)543 timer(int signo)
544 {
545 /* XXX longjmp/signal resource leaks */
546 if (++timeouts >= MAX_TIMEOUTS)
547 _exit(1);
548 longjmp(timeoutbuf, 1);
549 }
550
551 /*
552 * Send the requested file.
553 */
554 int
sendfile(struct formats * pf)555 sendfile(struct formats *pf)
556 {
557 struct tftphdr *dp, *r_init(void);
558 struct tftphdr *ap; /* ack packet */
559 volatile unsigned short block = 1;
560 int size, n;
561
562 signal(SIGALRM, timer);
563 dp = r_init();
564 ap = (struct tftphdr *)ackbuf;
565 do {
566 size = readit(file, &dp, pf->f_convert);
567 if (size < 0) {
568 nak(errno + 100);
569 goto abort;
570 }
571 dp->th_opcode = htons((u_short)DATA);
572 dp->th_block = htons((u_short)block);
573 timeouts = 0;
574 setjmp(timeoutbuf);
575
576 send_data:
577 if (send(peer, dp, size + 4, 0) != size + 4) {
578 syslog(LOG_ERR, "tftpd: write: %m");
579 goto abort;
580 }
581 read_ahead(file, pf->f_convert);
582 for ( ; ; ) {
583 alarm(rexmtval); /* read the ack */
584 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
585 alarm(0);
586 if (n < 0) {
587 syslog(LOG_ERR, "tftpd: read: %m");
588 goto abort;
589 }
590 ap->th_opcode = ntohs((u_short)ap->th_opcode);
591 ap->th_block = ntohs((u_short)ap->th_block);
592
593 if (ap->th_opcode == ERROR)
594 goto abort;
595
596 if (ap->th_opcode == ACK) {
597 if (ap->th_block == block) {
598 break;
599 }
600 /* Re-synchronize with the other side */
601 (void) synchnet(peer);
602 if (ap->th_block == (block -1)) {
603 goto send_data;
604 }
605 }
606
607 }
608 block++;
609 } while (size == SEGSIZE);
610 abort:
611 fclose(file);
612 return (1);
613 }
614
615 /* ARGSUSED */
616 static void
justquit(int signo)617 justquit(int signo)
618 {
619 _exit(0);
620 }
621
622
623 /*
624 * Receive a file.
625 */
626 int
recvfile(struct formats * pf)627 recvfile(struct formats *pf)
628 {
629 struct tftphdr *dp, *w_init(void);
630 struct tftphdr *ap; /* ack buffer */
631 volatile unsigned short block = 0;
632 int n, size;
633
634 signal(SIGALRM, timer);
635 dp = w_init();
636 ap = (struct tftphdr *)ackbuf;
637 do {
638 timeouts = 0;
639 ap->th_opcode = htons((u_short)ACK);
640 ap->th_block = htons((u_short)block);
641 block++;
642 setjmp(timeoutbuf);
643 send_ack:
644 if (send(peer, ackbuf, 4, 0) != 4) {
645 syslog(LOG_ERR, "tftpd: write: %m");
646 goto abort;
647 }
648 write_behind(file, pf->f_convert);
649 for ( ; ; ) {
650 alarm(rexmtval);
651 n = recv(peer, dp, PKTSIZE, 0);
652 alarm(0);
653 if (n < 0) { /* really? */
654 syslog(LOG_ERR, "tftpd: read: %m");
655 goto abort;
656 }
657 dp->th_opcode = ntohs((u_short)dp->th_opcode);
658 dp->th_block = ntohs((u_short)dp->th_block);
659 if (dp->th_opcode == ERROR)
660 goto abort;
661 if (dp->th_opcode == DATA) {
662 if (dp->th_block == block) {
663 break; /* normal */
664 }
665 /* Re-synchronize with the other side */
666 (void) synchnet(peer);
667 if (dp->th_block == (block-1))
668 goto send_ack; /* rexmit */
669 }
670 }
671 /* size = write(file, dp->th_data, n - 4); */
672 size = writeit(file, &dp, n - 4, pf->f_convert);
673 if (size != (n-4)) { /* ahem */
674 if (size < 0)
675 nak(errno + 100);
676 else nak(ENOSPACE);
677 goto abort;
678 }
679 } while (size == SEGSIZE);
680 write_behind(file, pf->f_convert);
681 (void) fclose(file); /* close data file */
682
683 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */
684 ap->th_block = htons((u_short)(block));
685 (void) send(peer, ackbuf, 4, 0);
686
687 signal(SIGALRM, justquit); /* just quit on timeout */
688 alarm(rexmtval);
689 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
690 alarm(0);
691 if (n >= 4 && /* if read some data */
692 dp->th_opcode == DATA && /* and got a data block */
693 block == dp->th_block) { /* then my last ack was lost */
694 (void) send(peer, ackbuf, 4, 0); /* resend final ack */
695 }
696 abort:
697 return (1);
698 }
699
700 struct errmsg {
701 int e_code;
702 const char *e_msg;
703 } errmsgs[] = {
704 { EUNDEF, "Undefined error code" },
705 { ENOTFOUND, "File not found" },
706 { EACCESS, "Access violation" },
707 { ENOSPACE, "Disk full or allocation exceeded" },
708 { EBADOP, "Illegal TFTP operation" },
709 { EBADID, "Unknown transfer ID" },
710 { EEXISTS, "File already exists" },
711 { ENOUSER, "No such user" },
712 { EOPTNEG, "Option negotiation failed" },
713 { -1, NULL }
714 };
715
716 /*
717 * Send a nak packet (error message).
718 * Error code passed in is one of the
719 * standard TFTP codes, or a UNIX errno
720 * offset by 100.
721 */
722 void
nak(int error)723 nak(int error)
724 {
725 struct tftphdr *tp;
726 struct errmsg *pe;
727 int length;
728
729 tp = (struct tftphdr *)buf;
730 tp->th_opcode = htons((u_short)ERROR);
731 tp->th_code = htons((u_short)error);
732 for (pe = errmsgs; pe->e_code >= 0; pe++)
733 if (pe->e_code == error)
734 break;
735 if (pe->e_code < 0) {
736 pe->e_msg = strerror(error - 100);
737 tp->th_code = EUNDEF; /* set 'undef' errorcode */
738 }
739 length = strlcpy(tp->th_msg, pe->e_msg, sizeof(buf)) + 5;
740 if (length > sizeof(buf))
741 length = sizeof(buf);
742 if (send(peer, buf, length, 0) != length)
743 syslog(LOG_ERR, "nak: %m");
744 }
745
746 /*
747 * Send an oack packet (option acknowledgement).
748 */
749 void
oack(void)750 oack(void)
751 {
752 struct tftphdr *tp, *ap;
753 int size, i, n;
754 char *bp;
755
756 tp = (struct tftphdr *)buf;
757 bp = buf + 2;
758 size = sizeof(buf) - 2;
759 tp->th_opcode = htons((u_short)OACK);
760 for (i = 0; options[i].o_type != NULL; i++) {
761 if (options[i].o_request) {
762 n = snprintf(bp, size, "%s%c%d", options[i].o_type,
763 0, options[i].o_reply);
764 if (n == -1 || n >= size) {
765 syslog(LOG_ERR, "oack: no buffer space");
766 exit(1);
767 }
768 bp += n+1;
769 size -= n+1;
770 if (size < 0) {
771 syslog(LOG_ERR, "oack: no buffer space");
772 exit(1);
773 }
774 }
775 }
776 size = bp - buf;
777 ap = (struct tftphdr *)ackbuf;
778 signal(SIGALRM, timer);
779 timeouts = 0;
780
781 (void)setjmp(timeoutbuf);
782 if (send(peer, buf, size, 0) != size) {
783 syslog(LOG_INFO, "oack: %m");
784 exit(1);
785 }
786
787 for (;;) {
788 alarm(rexmtval);
789 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
790 alarm(0);
791 if (n < 0) {
792 syslog(LOG_ERR, "recv: %m");
793 exit(1);
794 }
795 ap->th_opcode = ntohs((u_short)ap->th_opcode);
796 ap->th_block = ntohs((u_short)ap->th_block);
797 if (ap->th_opcode == ERROR)
798 exit(1);
799 if (ap->th_opcode == ACK && ap->th_block == 0)
800 break;
801 }
802 }
803