xref: /netbsd-src/usr.bin/netstat/if.c (revision eb7c1594f145c931049e1fd9eb056a5987e87e59)
1 /*	$NetBSD: if.c,v 1.55 2003/08/07 11:15:18 agc 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 1.55 2003/08/07 11:15:18 agc Exp $");
38 #endif
39 #endif /* not lint */
40 
41 #include <sys/types.h>
42 #include <sys/protosw.h>
43 #include <sys/socket.h>
44 
45 #include <net/if.h>
46 #include <net/if_dl.h>
47 #include <net/if_types.h>
48 #include <netinet/in.h>
49 #include <netinet/in_var.h>
50 #include <netns/ns.h>
51 #include <netns/ns_if.h>
52 #include <netiso/iso.h>
53 #include <netiso/iso_var.h>
54 #include <arpa/inet.h>
55 
56 #include <signal.h>
57 #include <stdio.h>
58 #include <stdlib.h>
59 #include <string.h>
60 #include <unistd.h>
61 #include <netdb.h>
62 
63 #include "netstat.h"
64 
65 #define	YES	1
66 #define	NO	0
67 
68 static void sidewaysintpr __P((u_int, u_long));
69 static void catchalarm __P((int));
70 
71 /*
72  * Print a description of the network interfaces.
73  * NOTE: ifnetaddr is the location of the kernel global "ifnet",
74  * which is a TAILQ_HEAD.
75  */
76 void
77 intpr(interval, ifnetaddr, pfunc)
78 	int interval;
79 	u_long ifnetaddr;
80 	void (*pfunc)(char *);
81 {
82 	struct ifnet ifnet;
83 	union {
84 		struct ifaddr ifa;
85 		struct in_ifaddr in;
86 #ifdef INET6
87 		struct in6_ifaddr in6;
88 #endif /* INET6 */
89 		struct ns_ifaddr ns;
90 		struct iso_ifaddr iso;
91 	} ifaddr;
92 	u_long ifaddraddr;
93 	struct sockaddr *sa;
94 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
95 	char name[IFNAMSIZ + 1];	/* + 1 for `*' */
96 	char hbuf[NI_MAXHOST];		/* for getnameinfo() */
97 #ifdef INET6
98 #ifdef NI_WITHSCOPEID
99 	const int niflag = NI_NUMERICHOST | NI_WITHSCOPEID;
100 #else
101 	const int niflag = NI_NUMERICHOST;
102 #endif
103 #endif
104 
105 	if (ifnetaddr == 0) {
106 		printf("ifnet: symbol not defined\n");
107 		return;
108 	}
109 	if (interval) {
110 		sidewaysintpr((unsigned)interval, ifnetaddr);
111 		return;
112 	}
113 
114 	/*
115 	 * Find the pointer to the first ifnet structure.  Replace
116 	 * the pointer to the TAILQ_HEAD with the actual pointer
117 	 * to the first list element.
118 	 */
119 	if (kread(ifnetaddr, (char *)&ifhead, sizeof ifhead))
120 		return;
121 	ifnetaddr = (u_long)ifhead.tqh_first;
122 
123 	if (!sflag & !pflag) {
124 		if (bflag) {
125 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
126 			       "%10.10s %10.10s",
127 			       "Name", "Mtu", "Network", "Address",
128 			       "Ibytes", "Obytes");
129 		} else {
130 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
131 			       "%8.8s %5.5s %8.8s %5.5s %5.5s",
132 			       "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs",
133 			       "Opkts", "Oerrs", "Colls");
134 		}
135 		if (tflag)
136 			printf(" %4.4s", "Time");
137 		if (dflag)
138 			printf(" %5.5s", "Drops");
139 		putchar('\n');
140 	}
141 	ifaddraddr = 0;
142 	while (ifnetaddr || ifaddraddr) {
143 		struct sockaddr_in *sin;
144 #ifdef INET6
145 		struct sockaddr_in6 *sin6;
146 #endif /* INET6 */
147 		char *cp;
148 		int n, m;
149 
150 		if (ifaddraddr == 0) {
151 			if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
152 				return;
153 			memmove(name, ifnet.if_xname, IFNAMSIZ);
154 			name[IFNAMSIZ - 1] = '\0';	/* sanity */
155 			ifnetaddr = (u_long)ifnet.if_list.tqe_next;
156 			if (interface != 0 && strcmp(name, interface) != 0)
157 				continue;
158 			cp = strchr(name, '\0');
159 
160 			if (pfunc) {
161 				(*pfunc)(name);
162 				continue;
163 			}
164 
165 			if ((ifnet.if_flags & IFF_UP) == 0)
166 				*cp++ = '*';
167 			*cp = '\0';
168 			ifaddraddr = (u_long)ifnet.if_addrlist.tqh_first;
169 		}
170 		if (vflag)
171 			n = strlen(name) < 5 ? 5 : strlen(name);
172 		else
173 			n = 5;
174 		printf("%-*.*s %-5llu ", n, n, name,
175 		    (unsigned long long)ifnet.if_mtu);
176 		if (ifaddraddr == 0) {
177 			printf("%-13.13s ", "none");
178 			printf("%-17.17s ", "none");
179 		} else {
180 			char hexsep = '.';		/* for hexprint */
181 			static const char hexfmt[] = "%02x%c";	/* for hexprint */
182 			if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
183 				ifaddraddr = 0;
184 				continue;
185 			}
186 #define CP(x) ((char *)(x))
187 			cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
188 				CP(&ifaddr); sa = (struct sockaddr *)cp;
189 			switch (sa->sa_family) {
190 			case AF_UNSPEC:
191 				printf("%-13.13s ", "none");
192 				printf("%-17.17s ", "none");
193 				break;
194 			case AF_INET:
195 				sin = (struct sockaddr_in *)sa;
196 #ifdef notdef
197 				/*
198 				 * can't use inet_makeaddr because kernel
199 				 * keeps nets unshifted.
200 				 */
201 				in = inet_makeaddr(ifaddr.in.ia_subnet,
202 					INADDR_ANY);
203 				cp = netname(in.s_addr,
204 					ifaddr.in.ia_subnetmask);
205 #else
206 				cp = netname(ifaddr.in.ia_subnet,
207 					ifaddr.in.ia_subnetmask);
208 #endif
209 				if (vflag)
210 					n = strlen(cp) < 13 ? 13 : strlen(cp);
211 				else
212 					n = 13;
213 				printf("%-*.*s ", n, n, cp);
214 				cp = routename(sin->sin_addr.s_addr);
215 				if (vflag)
216 					n = strlen(cp) < 17 ? 17 : strlen(cp);
217 				else
218 					n = 17;
219 				printf("%-*.*s ", n, n, cp);
220 				if (aflag) {
221 					u_long multiaddr;
222 					struct in_multi inm;
223 
224 					multiaddr = (u_long)
225 					    ifaddr.in.ia_multiaddrs.lh_first;
226 					while (multiaddr != 0) {
227 						kread(multiaddr, (char *)&inm,
228 						   sizeof inm);
229 						printf("\n%25s %-17.17s ", "",
230 						   routename(
231 						      inm.inm_addr.s_addr));
232 						multiaddr =
233 						   (u_long)inm.inm_list.le_next;
234 					}
235 				}
236 				break;
237 #ifdef INET6
238 			case AF_INET6:
239 				sin6 = (struct sockaddr_in6 *)sa;
240 #ifdef __KAME__
241 				if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
242 					sin6->sin6_scope_id =
243 						ntohs(*(u_int16_t *)
244 						  &sin6->sin6_addr.s6_addr[2]);
245 					/* too little width */
246 					if (!vflag)
247 						sin6->sin6_scope_id = 0;
248 					sin6->sin6_addr.s6_addr[2] = 0;
249 					sin6->sin6_addr.s6_addr[3] = 0;
250 				}
251 #endif
252 				cp = netname6(&ifaddr.in6.ia_addr,
253 					&ifaddr.in6.ia_prefixmask.sin6_addr);
254 				if (vflag)
255 					n = strlen(cp) < 13 ? 13 : strlen(cp);
256 				else
257 					n = 13;
258 				printf("%-*.*s ", n, n, cp);
259 				if (getnameinfo((struct sockaddr *)sin6,
260 						sin6->sin6_len,
261 						hbuf, sizeof(hbuf), NULL, 0,
262 						niflag) != 0) {
263 					cp = "?";
264 				} else
265 					cp = hbuf;
266 				if (vflag)
267 					n = strlen(cp) < 17 ? 17 : strlen(cp);
268 				else
269 					n = 17;
270 				printf("%-*.*s ", n, n, cp);
271 				if (aflag) {
272 					u_long multiaddr;
273 					struct in6_multi inm;
274 					struct sockaddr_in6 sin6;
275 
276 					multiaddr = (u_long)
277 					    ifaddr.in6.ia6_multiaddrs.lh_first;
278 					while (multiaddr != 0) {
279 						kread(multiaddr, (char *)&inm,
280 						   sizeof inm);
281 						memset(&sin6, 0, sizeof(sin6));
282 						sin6.sin6_len = sizeof(struct sockaddr_in6);
283 						sin6.sin6_family = AF_INET6;
284 						sin6.sin6_addr = inm.in6m_addr;
285 #ifdef __KAME__
286 						if (IN6_IS_ADDR_MC_LINKLOCAL(&sin6.sin6_addr)) {
287 							sin6.sin6_scope_id =
288 							    ntohs(*(u_int16_t *)
289 								&sin6.sin6_addr.s6_addr[2]);
290 							sin6.sin6_addr.s6_addr[2] = 0;
291 							sin6.sin6_addr.s6_addr[3] = 0;
292 						}
293 #endif
294 						if (getnameinfo((struct sockaddr *)&sin6,
295 						    sin6.sin6_len, hbuf,
296 						    sizeof(hbuf), NULL, 0,
297 						    niflag) != 0) {
298 							strlcpy(hbuf, "??",
299 							    sizeof(hbuf));
300 						}
301 						cp = hbuf;
302 						if (vflag)
303 						    n = strlen(cp) < 17
304 							? 17 : strlen(cp);
305 						else
306 						    n = 17;
307 						printf("\n%25s %-*.*s ", "",
308 						    n, n, cp);
309 						multiaddr =
310 						   (u_long)inm.in6m_entry.le_next;
311 					}
312 				}
313 				break;
314 #endif /*INET6*/
315 #ifndef SMALL
316 			case AF_APPLETALK:
317 				printf("atalk:%-7.7s ",
318 				       atalk_print(sa,0x10));
319 				printf("%-17.17s ", atalk_print(sa,0x0b));
320 				break;
321 			case AF_NS:
322 				{
323 				struct sockaddr_ns *sns =
324 					(struct sockaddr_ns *)sa;
325 				u_long net;
326 				char netnum[10];
327 
328 				*(union ns_net *)&net = sns->sns_addr.x_net;
329 				(void)snprintf(netnum, sizeof(netnum), "%xH",
330 				    (u_int32_t)ntohl(net));
331 				upHex(netnum);
332 				printf("ns:%-10s ", netnum);
333 				printf("%-17.17s ",
334 				    ns_phost((struct sockaddr *)sns));
335 				}
336 				break;
337 #endif
338 			case AF_LINK:
339 				printf("%-13.13s ", "<Link>");
340 				if (getnameinfo(sa, sa->sa_len,
341 				    hbuf, sizeof(hbuf), NULL, 0,
342 				    NI_NUMERICHOST) != 0) {
343 					cp = "?";
344 				} else
345 					cp = hbuf;
346 				if (vflag)
347 					n = strlen(cp) < 17 ? 17 : strlen(cp);
348 				else
349 					n = 17;
350 				printf("%-*.*s ", n, n, cp);
351 				break;
352 
353 			default:
354 				m = printf("(%d)", sa->sa_family);
355 				for (cp = sa->sa_len + (char *)sa;
356 					--cp > sa->sa_data && (*cp == 0);) {}
357 				n = cp - sa->sa_data + 1;
358 				cp = sa->sa_data;
359 				while (--n >= 0)
360 					m += printf(hexfmt, *cp++ & 0xff,
361 						    n > 0 ? hexsep : ' ');
362 				m = 32 - m;
363 				while (m-- > 0)
364 					putchar(' ');
365 				break;
366 			}
367 			ifaddraddr = (u_long)ifaddr.ifa.ifa_list.tqe_next;
368 		}
369 		if (bflag) {
370 			printf("%10llu %10llu",
371 				(unsigned long long)ifnet.if_ibytes,
372 				(unsigned long long)ifnet.if_obytes);
373 		} else {
374 			printf("%8llu %5llu %8llu %5llu %5llu",
375 				(unsigned long long)ifnet.if_ipackets,
376 				(unsigned long long)ifnet.if_ierrors,
377 				(unsigned long long)ifnet.if_opackets,
378 				(unsigned long long)ifnet.if_oerrors,
379 				(unsigned long long)ifnet.if_collisions);
380 		}
381 		if (tflag)
382 			printf(" %4d", ifnet.if_timer);
383 		if (dflag)
384 			printf(" %5d", ifnet.if_snd.ifq_drops);
385 		putchar('\n');
386 	}
387 }
388 
389 #define	MAXIF	100
390 struct	iftot {
391 	char ift_name[IFNAMSIZ];	/* interface name */
392 	u_quad_t ift_ip;		/* input packets */
393 	u_quad_t ift_ib;		/* input bytes */
394 	u_quad_t ift_ie;		/* input errors */
395 	u_quad_t ift_op;		/* output packets */
396 	u_quad_t ift_ob;		/* output bytes */
397 	u_quad_t ift_oe;		/* output errors */
398 	u_quad_t ift_co;		/* collisions */
399 	int ift_dr;			/* drops */
400 } iftot[MAXIF];
401 
402 u_char	signalled;			/* set if alarm goes off "early" */
403 
404 /*
405  * Print a running summary of interface statistics.
406  * Repeat display every interval seconds, showing statistics
407  * collected over that interval.  Assumes that interval is non-zero.
408  * First line printed at top of screen is always cumulative.
409  */
410 static void
411 sidewaysintpr(interval, off)
412 	unsigned interval;
413 	u_long off;
414 {
415 	struct ifnet ifnet;
416 	u_long firstifnet;
417 	struct iftot *ip, *total;
418 	int line;
419 	struct iftot *lastif, *sum, *interesting;
420 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
421 	int oldmask;
422 
423 	/*
424 	 * Find the pointer to the first ifnet structure.  Replace
425 	 * the pointer to the TAILQ_HEAD with the actual pointer
426 	 * to the first list element.
427 	 */
428 	if (kread(off, (char *)&ifhead, sizeof ifhead))
429 		return;
430 	firstifnet = (u_long)ifhead.tqh_first;
431 
432 	lastif = iftot;
433 	sum = iftot + MAXIF - 1;
434 	total = sum - 1;
435 	interesting = (interface == NULL) ? iftot : NULL;
436 	for (off = firstifnet, ip = iftot; off;) {
437 		if (kread(off, (char *)&ifnet, sizeof ifnet))
438 			break;
439 		memset(ip->ift_name, 0, sizeof(ip->ift_name));
440 		snprintf(ip->ift_name, IFNAMSIZ, "%s", ifnet.if_xname);
441 		if (interface && strcmp(ifnet.if_xname, interface) == 0)
442 			interesting = ip;
443 		ip++;
444 		if (ip >= iftot + MAXIF - 2)
445 			break;
446 		off = (u_long)ifnet.if_list.tqe_next;
447 	}
448 	if (interesting == NULL) {
449 		fprintf(stderr, "%s: %s: unknown interface\n",
450 		    getprogname(), interface);
451 		exit(1);
452 	}
453 	lastif = ip;
454 
455 	(void)signal(SIGALRM, catchalarm);
456 	signalled = NO;
457 	(void)alarm(interval);
458 banner:
459 	if (bflag)
460 		printf("%7.7s in %8.8s %6.6s out %5.5s",
461 		    interesting->ift_name, " ",
462 		    interesting->ift_name, " ");
463 	else
464 		printf("%5.5s in %5.5s%5.5s out %5.5s %5.5s",
465 		    interesting->ift_name, " ",
466 		    interesting->ift_name, " ", " ");
467 	if (dflag)
468 		printf(" %5.5s", " ");
469 	if (lastif - iftot > 0) {
470 		if (bflag)
471 			printf("  %7.7s in %8.8s %6.6s out %5.5s",
472 			    "total", " ", "total", " ");
473 		else
474 			printf("  %5.5s in %5.5s%5.5s out %5.5s %5.5s",
475 			    "total", " ", "total", " ", " ");
476 		if (dflag)
477 			printf(" %5.5s", " ");
478 	}
479 	for (ip = iftot; ip < iftot + MAXIF; ip++) {
480 		ip->ift_ip = 0;
481 		ip->ift_ib = 0;
482 		ip->ift_ie = 0;
483 		ip->ift_op = 0;
484 		ip->ift_ob = 0;
485 		ip->ift_oe = 0;
486 		ip->ift_co = 0;
487 		ip->ift_dr = 0;
488 	}
489 	putchar('\n');
490 	if (bflag)
491 		printf("%10.10s %8.8s %10.10s %5.5s",
492 		    "bytes", " ", "bytes", " ");
493 	else
494 		printf("%8.8s %5.5s %8.8s %5.5s %5.5s",
495 		    "packets", "errs", "packets", "errs", "colls");
496 	if (dflag)
497 		printf(" %5.5s", "drops");
498 	if (lastif - iftot > 0) {
499 		if (bflag)
500 			printf("  %10.10s %8.8s %10.10s %5.5s",
501 			    "bytes", " ", "bytes", " ");
502 		else
503 			printf("  %8.8s %5.5s %8.8s %5.5s %5.5s",
504 			    "packets", "errs", "packets", "errs", "colls");
505 		if (dflag)
506 			printf(" %5.5s", "drops");
507 	}
508 	putchar('\n');
509 	fflush(stdout);
510 	line = 0;
511 loop:
512 	sum->ift_ip = 0;
513 	sum->ift_ib = 0;
514 	sum->ift_ie = 0;
515 	sum->ift_op = 0;
516 	sum->ift_ob = 0;
517 	sum->ift_oe = 0;
518 	sum->ift_co = 0;
519 	sum->ift_dr = 0;
520 	for (off = firstifnet, ip = iftot; off && ip < lastif; ip++) {
521 		if (kread(off, (char *)&ifnet, sizeof ifnet)) {
522 			off = 0;
523 			continue;
524 		}
525 		if (ip == interesting) {
526 			if (bflag) {
527 				printf("%10llu %8.8s %10llu %5.5s",
528 				    (unsigned long long)(ifnet.if_ibytes -
529 					ip->ift_ib), " ",
530 				    (unsigned long long)(ifnet.if_obytes -
531 					ip->ift_ob), " ");
532 			} else {
533 				printf("%8llu %5llu %8llu %5llu %5llu",
534 				    (unsigned long long)
535 					(ifnet.if_ipackets - ip->ift_ip),
536 				    (unsigned long long)
537 					(ifnet.if_ierrors - ip->ift_ie),
538 				    (unsigned long long)
539 					(ifnet.if_opackets - ip->ift_op),
540 				    (unsigned long long)
541 					(ifnet.if_oerrors - ip->ift_oe),
542 				    (unsigned long long)
543 					(ifnet.if_collisions - ip->ift_co));
544 			}
545 			if (dflag)
546 				printf(" %5llu",
547 				    (unsigned long long)
548 					(ifnet.if_snd.ifq_drops - ip->ift_dr));
549 		}
550 		ip->ift_ip = ifnet.if_ipackets;
551 		ip->ift_ib = ifnet.if_ibytes;
552 		ip->ift_ie = ifnet.if_ierrors;
553 		ip->ift_op = ifnet.if_opackets;
554 		ip->ift_ob = ifnet.if_obytes;
555 		ip->ift_oe = ifnet.if_oerrors;
556 		ip->ift_co = ifnet.if_collisions;
557 		ip->ift_dr = ifnet.if_snd.ifq_drops;
558 		sum->ift_ip += ip->ift_ip;
559 		sum->ift_ib += ip->ift_ib;
560 		sum->ift_ie += ip->ift_ie;
561 		sum->ift_op += ip->ift_op;
562 		sum->ift_ob += ip->ift_ob;
563 		sum->ift_oe += ip->ift_oe;
564 		sum->ift_co += ip->ift_co;
565 		sum->ift_dr += ip->ift_dr;
566 		off = (u_long)ifnet.if_list.tqe_next;
567 	}
568 	if (lastif - iftot > 0) {
569 		if (bflag) {
570 			printf("  %10llu %8.8s %10llu %5.5s",
571 			    (unsigned long long)
572 				(sum->ift_ib - total->ift_ib), " ",
573 			    (unsigned long long)
574 				(sum->ift_ob - total->ift_ob), " ");
575 		} else {
576 			printf("  %8llu %5llu %8llu %5llu %5llu",
577 			    (unsigned long long)
578 				(sum->ift_ip - total->ift_ip),
579 			    (unsigned long long)
580 				(sum->ift_ie - total->ift_ie),
581 			    (unsigned long long)
582 				(sum->ift_op - total->ift_op),
583 			    (unsigned long long)
584 				(sum->ift_oe - total->ift_oe),
585 			    (unsigned long long)
586 				(sum->ift_co - total->ift_co));
587 		}
588 		if (dflag)
589 			printf(" %5llu",
590 			    (unsigned long long)(sum->ift_dr - total->ift_dr));
591 	}
592 	*total = *sum;
593 	putchar('\n');
594 	fflush(stdout);
595 	line++;
596 	oldmask = sigblock(sigmask(SIGALRM));
597 	if (! signalled) {
598 		sigpause(0);
599 	}
600 	sigsetmask(oldmask);
601 	signalled = NO;
602 	(void)alarm(interval);
603 	if (line == 21)
604 		goto banner;
605 	goto loop;
606 	/*NOTREACHED*/
607 }
608 
609 /*
610  * Called if an interval expires before sidewaysintpr has completed a loop.
611  * Sets a flag to not wait for the alarm.
612  */
613 static void
614 catchalarm(signo)
615 	int signo;
616 {
617 
618 	signalled = YES;
619 }
620