xref: /netbsd-src/usr.bin/netstat/if.c (revision 69b6d498973bb4d7230c2d3c12bd9a032738ec8e)
1 /*	$NetBSD: if.c,v 1.58 2004/11/16 05:59:32 itojun Exp $	*/
2 
3 /*
4  * Copyright (c) 1983, 1988, 1993
5  *	The Regents of the University of California.  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 #ifndef lint
34 #if 0
35 static char sccsid[] = "from: @(#)if.c	8.2 (Berkeley) 2/21/94";
36 #else
37 __RCSID("$NetBSD: if.c,v 1.58 2004/11/16 05:59:32 itojun Exp $");
38 #endif
39 #endif /* not lint */
40 
41 #include <sys/types.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 #include <sys/time.h>
45 
46 #include <net/if.h>
47 #include <net/if_dl.h>
48 #include <net/if_types.h>
49 #include <netinet/in.h>
50 #include <netinet/in_var.h>
51 #include <netns/ns.h>
52 #include <netns/ns_if.h>
53 #include <netiso/iso.h>
54 #include <netiso/iso_var.h>
55 #include <arpa/inet.h>
56 
57 #include <signal.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 #include <netdb.h>
63 
64 #include "netstat.h"
65 
66 #define	YES	1
67 #define	NO	0
68 
69 static void sidewaysintpr __P((u_int, u_long));
70 static void catchalarm __P((int));
71 
72 /*
73  * Print a description of the network interfaces.
74  * NOTE: ifnetaddr is the location of the kernel global "ifnet",
75  * which is a TAILQ_HEAD.
76  */
77 void
78 intpr(interval, ifnetaddr, pfunc)
79 	int interval;
80 	u_long ifnetaddr;
81 	void (*pfunc)(char *);
82 {
83 	struct ifnet ifnet;
84 	union {
85 		struct ifaddr ifa;
86 		struct in_ifaddr in;
87 #ifdef INET6
88 		struct in6_ifaddr in6;
89 #endif /* INET6 */
90 		struct ns_ifaddr ns;
91 		struct iso_ifaddr iso;
92 	} ifaddr;
93 	u_long ifaddraddr;
94 	struct sockaddr *sa;
95 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
96 	char name[IFNAMSIZ + 1];	/* + 1 for `*' */
97 	char hbuf[NI_MAXHOST];		/* for getnameinfo() */
98 #ifdef INET6
99 	const int niflag = NI_NUMERICHOST;
100 #endif
101 
102 	if (ifnetaddr == 0) {
103 		printf("ifnet: symbol not defined\n");
104 		return;
105 	}
106 	if (interval) {
107 		sidewaysintpr((unsigned)interval, ifnetaddr);
108 		return;
109 	}
110 
111 	/*
112 	 * Find the pointer to the first ifnet structure.  Replace
113 	 * the pointer to the TAILQ_HEAD with the actual pointer
114 	 * to the first list element.
115 	 */
116 	if (kread(ifnetaddr, (char *)&ifhead, sizeof ifhead))
117 		return;
118 	ifnetaddr = (u_long)ifhead.tqh_first;
119 
120 	if (!sflag & !pflag) {
121 		if (bflag) {
122 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
123 			       "%10.10s %10.10s",
124 			       "Name", "Mtu", "Network", "Address",
125 			       "Ibytes", "Obytes");
126 		} else {
127 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
128 			       "%8.8s %5.5s %8.8s %5.5s %5.5s",
129 			       "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs",
130 			       "Opkts", "Oerrs", "Colls");
131 		}
132 		if (tflag)
133 			printf(" %4.4s", "Time");
134 		if (dflag)
135 			printf(" %5.5s", "Drops");
136 		putchar('\n');
137 	}
138 	ifaddraddr = 0;
139 	while (ifnetaddr || ifaddraddr) {
140 		struct sockaddr_in *sin;
141 #ifdef INET6
142 		struct sockaddr_in6 *sin6;
143 #endif /* INET6 */
144 		char *cp;
145 		int n, m;
146 
147 		if (ifaddraddr == 0) {
148 			if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
149 				return;
150 			memmove(name, ifnet.if_xname, IFNAMSIZ);
151 			name[IFNAMSIZ - 1] = '\0';	/* sanity */
152 			ifnetaddr = (u_long)ifnet.if_list.tqe_next;
153 			if (interface != 0 && strcmp(name, interface) != 0)
154 				continue;
155 			cp = strchr(name, '\0');
156 
157 			if (pfunc) {
158 				(*pfunc)(name);
159 				continue;
160 			}
161 
162 			if ((ifnet.if_flags & IFF_UP) == 0)
163 				*cp++ = '*';
164 			*cp = '\0';
165 			ifaddraddr = (u_long)ifnet.if_addrlist.tqh_first;
166 		}
167 		if (vflag)
168 			n = strlen(name) < 5 ? 5 : strlen(name);
169 		else
170 			n = 5;
171 		printf("%-*.*s %-5llu ", n, n, name,
172 		    (unsigned long long)ifnet.if_mtu);
173 		if (ifaddraddr == 0) {
174 			printf("%-13.13s ", "none");
175 			printf("%-17.17s ", "none");
176 		} else {
177 			char hexsep = '.';		/* for hexprint */
178 			static const char hexfmt[] = "%02x%c";	/* for hexprint */
179 			if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
180 				ifaddraddr = 0;
181 				continue;
182 			}
183 #define CP(x) ((char *)(x))
184 			cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
185 			    CP(&ifaddr);
186 			sa = (struct sockaddr *)cp;
187 			switch (sa->sa_family) {
188 			case AF_UNSPEC:
189 				printf("%-13.13s ", "none");
190 				printf("%-17.17s ", "none");
191 				break;
192 			case AF_INET:
193 				sin = (struct sockaddr_in *)sa;
194 #ifdef notdef
195 				/*
196 				 * can't use inet_makeaddr because kernel
197 				 * keeps nets unshifted.
198 				 */
199 				in = inet_makeaddr(ifaddr.in.ia_subnet,
200 					INADDR_ANY);
201 				cp = netname(in.s_addr,
202 					ifaddr.in.ia_subnetmask);
203 #else
204 				cp = netname(ifaddr.in.ia_subnet,
205 					ifaddr.in.ia_subnetmask);
206 #endif
207 				if (vflag)
208 					n = strlen(cp) < 13 ? 13 : strlen(cp);
209 				else
210 					n = 13;
211 				printf("%-*.*s ", n, n, cp);
212 				cp = routename(sin->sin_addr.s_addr);
213 				if (vflag)
214 					n = strlen(cp) < 17 ? 17 : strlen(cp);
215 				else
216 					n = 17;
217 				printf("%-*.*s ", n, n, cp);
218 				if (aflag) {
219 					u_long multiaddr;
220 					struct in_multi inm;
221 
222 					multiaddr = (u_long)
223 					    ifaddr.in.ia_multiaddrs.lh_first;
224 					while (multiaddr != 0) {
225 						kread(multiaddr, (char *)&inm,
226 						   sizeof inm);
227 						printf("\n%25s %-17.17s ", "",
228 						   routename(
229 						      inm.inm_addr.s_addr));
230 						multiaddr =
231 						   (u_long)inm.inm_list.le_next;
232 					}
233 				}
234 				break;
235 #ifdef INET6
236 			case AF_INET6:
237 				sin6 = (struct sockaddr_in6 *)sa;
238 #ifdef __KAME__
239 				if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
240 					sin6->sin6_scope_id =
241 						ntohs(*(u_int16_t *)
242 						  &sin6->sin6_addr.s6_addr[2]);
243 					/* too little width */
244 					if (!vflag)
245 						sin6->sin6_scope_id = 0;
246 					sin6->sin6_addr.s6_addr[2] = 0;
247 					sin6->sin6_addr.s6_addr[3] = 0;
248 				}
249 #endif
250 				cp = netname6(&ifaddr.in6.ia_addr,
251 					&ifaddr.in6.ia_prefixmask.sin6_addr);
252 				if (vflag)
253 					n = strlen(cp) < 13 ? 13 : strlen(cp);
254 				else
255 					n = 13;
256 				printf("%-*.*s ", n, n, cp);
257 				if (getnameinfo((struct sockaddr *)sin6,
258 						sin6->sin6_len,
259 						hbuf, sizeof(hbuf), NULL, 0,
260 						niflag) != 0) {
261 					cp = "?";
262 				} else
263 					cp = hbuf;
264 				if (vflag)
265 					n = strlen(cp) < 17 ? 17 : strlen(cp);
266 				else
267 					n = 17;
268 				printf("%-*.*s ", n, n, cp);
269 				if (aflag) {
270 					u_long multiaddr;
271 					struct in6_multi inm;
272 					struct sockaddr_in6 sin6;
273 
274 					multiaddr = (u_long)
275 					    ifaddr.in6.ia6_multiaddrs.lh_first;
276 					while (multiaddr != 0) {
277 						kread(multiaddr, (char *)&inm,
278 						   sizeof inm);
279 						memset(&sin6, 0, sizeof(sin6));
280 						sin6.sin6_len = sizeof(struct sockaddr_in6);
281 						sin6.sin6_family = AF_INET6;
282 						sin6.sin6_addr = inm.in6m_addr;
283 #ifdef __KAME__
284 						if (IN6_IS_ADDR_MC_LINKLOCAL(&sin6.sin6_addr)) {
285 							sin6.sin6_scope_id =
286 							    ntohs(*(u_int16_t *)
287 								&sin6.sin6_addr.s6_addr[2]);
288 							sin6.sin6_addr.s6_addr[2] = 0;
289 							sin6.sin6_addr.s6_addr[3] = 0;
290 						}
291 #endif
292 						if (getnameinfo((struct sockaddr *)&sin6,
293 						    sin6.sin6_len, hbuf,
294 						    sizeof(hbuf), NULL, 0,
295 						    niflag) != 0) {
296 							strlcpy(hbuf, "??",
297 							    sizeof(hbuf));
298 						}
299 						cp = hbuf;
300 						if (vflag)
301 						    n = strlen(cp) < 17
302 							? 17 : strlen(cp);
303 						else
304 						    n = 17;
305 						printf("\n%25s %-*.*s ", "",
306 						    n, n, cp);
307 						multiaddr =
308 						   (u_long)inm.in6m_entry.le_next;
309 					}
310 				}
311 				break;
312 #endif /*INET6*/
313 #ifndef SMALL
314 			case AF_APPLETALK:
315 				printf("atalk:%-7.7s ",
316 				       atalk_print(sa,0x10));
317 				printf("%-17.17s ", atalk_print(sa,0x0b));
318 				break;
319 			case AF_NS:
320 				{
321 				struct sockaddr_ns *sns =
322 					(struct sockaddr_ns *)sa;
323 				u_long net;
324 				char netnum[10];
325 
326 				*(union ns_net *)&net = sns->sns_addr.x_net;
327 				(void)snprintf(netnum, sizeof(netnum), "%xH",
328 				    (u_int32_t)ntohl(net));
329 				upHex(netnum);
330 				printf("ns:%-10s ", netnum);
331 				printf("%-17.17s ",
332 				    ns_phost((struct sockaddr *)sns));
333 				}
334 				break;
335 #endif
336 			case AF_LINK:
337 				printf("%-13.13s ", "<Link>");
338 				if (getnameinfo(sa, sa->sa_len,
339 				    hbuf, sizeof(hbuf), NULL, 0,
340 				    NI_NUMERICHOST) != 0) {
341 					cp = "?";
342 				} else
343 					cp = hbuf;
344 				if (vflag)
345 					n = strlen(cp) < 17 ? 17 : strlen(cp);
346 				else
347 					n = 17;
348 				printf("%-*.*s ", n, n, cp);
349 				break;
350 
351 			default:
352 				m = printf("(%d)", sa->sa_family);
353 				for (cp = sa->sa_len + (char *)sa;
354 					--cp > sa->sa_data && (*cp == 0);) {}
355 				n = cp - sa->sa_data + 1;
356 				cp = sa->sa_data;
357 				while (--n >= 0)
358 					m += printf(hexfmt, *cp++ & 0xff,
359 						    n > 0 ? hexsep : ' ');
360 				m = 32 - m;
361 				while (m-- > 0)
362 					putchar(' ');
363 				break;
364 			}
365 			ifaddraddr = (u_long)ifaddr.ifa.ifa_list.tqe_next;
366 		}
367 		if (bflag) {
368 			printf("%10llu %10llu",
369 				(unsigned long long)ifnet.if_ibytes,
370 				(unsigned long long)ifnet.if_obytes);
371 		} else {
372 			printf("%8llu %5llu %8llu %5llu %5llu",
373 				(unsigned long long)ifnet.if_ipackets,
374 				(unsigned long long)ifnet.if_ierrors,
375 				(unsigned long long)ifnet.if_opackets,
376 				(unsigned long long)ifnet.if_oerrors,
377 				(unsigned long long)ifnet.if_collisions);
378 		}
379 		if (tflag)
380 			printf(" %4d", ifnet.if_timer);
381 		if (dflag)
382 			printf(" %5d", ifnet.if_snd.ifq_drops);
383 		putchar('\n');
384 	}
385 }
386 
387 #define	MAXIF	100
388 struct	iftot {
389 	char ift_name[IFNAMSIZ];	/* interface name */
390 	u_quad_t ift_ip;		/* input packets */
391 	u_quad_t ift_ib;		/* input bytes */
392 	u_quad_t ift_ie;		/* input errors */
393 	u_quad_t ift_op;		/* output packets */
394 	u_quad_t ift_ob;		/* output bytes */
395 	u_quad_t ift_oe;		/* output errors */
396 	u_quad_t ift_co;		/* collisions */
397 	int ift_dr;			/* drops */
398 } iftot[MAXIF];
399 
400 u_char	signalled;			/* set if alarm goes off "early" */
401 
402 /*
403  * Print a running summary of interface statistics.
404  * Repeat display every interval seconds, showing statistics
405  * collected over that interval.  Assumes that interval is non-zero.
406  * First line printed at top of screen is always cumulative.
407  */
408 static void
409 sidewaysintpr(interval, off)
410 	unsigned interval;
411 	u_long off;
412 {
413 	struct itimerval it;
414 	struct ifnet ifnet;
415 	u_long firstifnet;
416 	struct iftot *ip, *total;
417 	int line;
418 	struct iftot *lastif, *sum, *interesting;
419 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
420 	int oldmask;
421 
422 	/*
423 	 * Find the pointer to the first ifnet structure.  Replace
424 	 * the pointer to the TAILQ_HEAD with the actual pointer
425 	 * to the first list element.
426 	 */
427 	if (kread(off, (char *)&ifhead, sizeof ifhead))
428 		return;
429 	firstifnet = (u_long)ifhead.tqh_first;
430 
431 	lastif = iftot;
432 	sum = iftot + MAXIF - 1;
433 	total = sum - 1;
434 	interesting = (interface == NULL) ? iftot : NULL;
435 	for (off = firstifnet, ip = iftot; off;) {
436 		if (kread(off, (char *)&ifnet, sizeof ifnet))
437 			break;
438 		memset(ip->ift_name, 0, sizeof(ip->ift_name));
439 		snprintf(ip->ift_name, IFNAMSIZ, "%s", ifnet.if_xname);
440 		if (interface && strcmp(ifnet.if_xname, interface) == 0)
441 			interesting = ip;
442 		ip++;
443 		if (ip >= iftot + MAXIF - 2)
444 			break;
445 		off = (u_long)ifnet.if_list.tqe_next;
446 	}
447 	if (interesting == NULL) {
448 		fprintf(stderr, "%s: %s: unknown interface\n",
449 		    getprogname(), interface);
450 		exit(1);
451 	}
452 	lastif = ip;
453 
454 	(void)signal(SIGALRM, catchalarm);
455 	signalled = NO;
456 
457 	it.it_interval.tv_sec = it.it_value.tv_sec = interval;
458 	it.it_interval.tv_usec = it.it_value.tv_usec = 0;
459 	setitimer(ITIMER_REAL, &it, NULL);
460 
461 banner:
462 	if (bflag)
463 		printf("%7.7s in %8.8s %6.6s out %5.5s",
464 		    interesting->ift_name, " ",
465 		    interesting->ift_name, " ");
466 	else
467 		printf("%5.5s in %5.5s%5.5s out %5.5s %5.5s",
468 		    interesting->ift_name, " ",
469 		    interesting->ift_name, " ", " ");
470 	if (dflag)
471 		printf(" %5.5s", " ");
472 	if (lastif - iftot > 0) {
473 		if (bflag)
474 			printf("  %7.7s in %8.8s %6.6s out %5.5s",
475 			    "total", " ", "total", " ");
476 		else
477 			printf("  %5.5s in %5.5s%5.5s out %5.5s %5.5s",
478 			    "total", " ", "total", " ", " ");
479 		if (dflag)
480 			printf(" %5.5s", " ");
481 	}
482 	for (ip = iftot; ip < iftot + MAXIF; ip++) {
483 		ip->ift_ip = 0;
484 		ip->ift_ib = 0;
485 		ip->ift_ie = 0;
486 		ip->ift_op = 0;
487 		ip->ift_ob = 0;
488 		ip->ift_oe = 0;
489 		ip->ift_co = 0;
490 		ip->ift_dr = 0;
491 	}
492 	putchar('\n');
493 	if (bflag)
494 		printf("%10.10s %8.8s %10.10s %5.5s",
495 		    "bytes", " ", "bytes", " ");
496 	else
497 		printf("%8.8s %5.5s %8.8s %5.5s %5.5s",
498 		    "packets", "errs", "packets", "errs", "colls");
499 	if (dflag)
500 		printf(" %5.5s", "drops");
501 	if (lastif - iftot > 0) {
502 		if (bflag)
503 			printf("  %10.10s %8.8s %10.10s %5.5s",
504 			    "bytes", " ", "bytes", " ");
505 		else
506 			printf("  %8.8s %5.5s %8.8s %5.5s %5.5s",
507 			    "packets", "errs", "packets", "errs", "colls");
508 		if (dflag)
509 			printf(" %5.5s", "drops");
510 	}
511 	putchar('\n');
512 	fflush(stdout);
513 	line = 0;
514 loop:
515 	sum->ift_ip = 0;
516 	sum->ift_ib = 0;
517 	sum->ift_ie = 0;
518 	sum->ift_op = 0;
519 	sum->ift_ob = 0;
520 	sum->ift_oe = 0;
521 	sum->ift_co = 0;
522 	sum->ift_dr = 0;
523 	for (off = firstifnet, ip = iftot; off && ip < lastif; ip++) {
524 		if (kread(off, (char *)&ifnet, sizeof ifnet)) {
525 			off = 0;
526 			continue;
527 		}
528 		if (ip == interesting) {
529 			if (bflag) {
530 				printf("%10llu %8.8s %10llu %5.5s",
531 				    (unsigned long long)(ifnet.if_ibytes -
532 					ip->ift_ib), " ",
533 				    (unsigned long long)(ifnet.if_obytes -
534 					ip->ift_ob), " ");
535 			} else {
536 				printf("%8llu %5llu %8llu %5llu %5llu",
537 				    (unsigned long long)
538 					(ifnet.if_ipackets - ip->ift_ip),
539 				    (unsigned long long)
540 					(ifnet.if_ierrors - ip->ift_ie),
541 				    (unsigned long long)
542 					(ifnet.if_opackets - ip->ift_op),
543 				    (unsigned long long)
544 					(ifnet.if_oerrors - ip->ift_oe),
545 				    (unsigned long long)
546 					(ifnet.if_collisions - ip->ift_co));
547 			}
548 			if (dflag)
549 				printf(" %5llu",
550 				    (unsigned long long)
551 					(ifnet.if_snd.ifq_drops - ip->ift_dr));
552 		}
553 		ip->ift_ip = ifnet.if_ipackets;
554 		ip->ift_ib = ifnet.if_ibytes;
555 		ip->ift_ie = ifnet.if_ierrors;
556 		ip->ift_op = ifnet.if_opackets;
557 		ip->ift_ob = ifnet.if_obytes;
558 		ip->ift_oe = ifnet.if_oerrors;
559 		ip->ift_co = ifnet.if_collisions;
560 		ip->ift_dr = ifnet.if_snd.ifq_drops;
561 		sum->ift_ip += ip->ift_ip;
562 		sum->ift_ib += ip->ift_ib;
563 		sum->ift_ie += ip->ift_ie;
564 		sum->ift_op += ip->ift_op;
565 		sum->ift_ob += ip->ift_ob;
566 		sum->ift_oe += ip->ift_oe;
567 		sum->ift_co += ip->ift_co;
568 		sum->ift_dr += ip->ift_dr;
569 		off = (u_long)ifnet.if_list.tqe_next;
570 	}
571 	if (lastif - iftot > 0) {
572 		if (bflag) {
573 			printf("  %10llu %8.8s %10llu %5.5s",
574 			    (unsigned long long)
575 				(sum->ift_ib - total->ift_ib), " ",
576 			    (unsigned long long)
577 				(sum->ift_ob - total->ift_ob), " ");
578 		} else {
579 			printf("  %8llu %5llu %8llu %5llu %5llu",
580 			    (unsigned long long)
581 				(sum->ift_ip - total->ift_ip),
582 			    (unsigned long long)
583 				(sum->ift_ie - total->ift_ie),
584 			    (unsigned long long)
585 				(sum->ift_op - total->ift_op),
586 			    (unsigned long long)
587 				(sum->ift_oe - total->ift_oe),
588 			    (unsigned long long)
589 				(sum->ift_co - total->ift_co));
590 		}
591 		if (dflag)
592 			printf(" %5llu",
593 			    (unsigned long long)(sum->ift_dr - total->ift_dr));
594 	}
595 	*total = *sum;
596 	putchar('\n');
597 	fflush(stdout);
598 	line++;
599 	oldmask = sigblock(sigmask(SIGALRM));
600 	if (! signalled) {
601 		sigpause(0);
602 	}
603 	sigsetmask(oldmask);
604 	signalled = NO;
605 	if (line == 21)
606 		goto banner;
607 	goto loop;
608 	/*NOTREACHED*/
609 }
610 
611 /*
612  * Called if an interval expires before sidewaysintpr has completed a loop.
613  * Sets a flag to not wait for the alarm.
614  */
615 static void
616 catchalarm(signo)
617 	int signo;
618 {
619 
620 	signalled = YES;
621 }
622