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if.c revision 1.38
      1 /*	$NetBSD: if.c,v 1.38 2000/02/05 17:39:22 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "from: @(#)if.c	8.2 (Berkeley) 2/21/94";
     40 #else
     41 __RCSID("$NetBSD: if.c,v 1.38 2000/02/05 17:39:22 itojun Exp $");
     42 #endif
     43 #endif /* not lint */
     44 
     45 #include <sys/types.h>
     46 #include <sys/protosw.h>
     47 #include <sys/socket.h>
     48 
     49 #include <net/if.h>
     50 #include <net/if_dl.h>
     51 #include <net/if_types.h>
     52 #include <netinet/in.h>
     53 #include <netinet/in_var.h>
     54 #include <netns/ns.h>
     55 #include <netns/ns_if.h>
     56 #include <netiso/iso.h>
     57 #include <netiso/iso_var.h>
     58 #include <arpa/inet.h>
     59 
     60 #include <signal.h>
     61 #include <stdio.h>
     62 #include <string.h>
     63 #include <unistd.h>
     64 #include <netdb.h>
     65 
     66 #include "netstat.h"
     67 
     68 #define	YES	1
     69 #define	NO	0
     70 
     71 static void sidewaysintpr __P((u_int, u_long));
     72 static void catchalarm __P((int));
     73 
     74 #ifdef INET6
     75 char *netname6 __P((struct sockaddr_in6 *, struct in6_addr *));
     76 #endif
     77 
     78 /*
     79  * Print a description of the network interfaces.
     80  * NOTE: ifnetaddr is the location of the kernel global "ifnet",
     81  * which is a TAILQ_HEAD.
     82  */
     83 void
     84 intpr(interval, ifnetaddr, pfunc)
     85 	int interval;
     86 	u_long ifnetaddr;
     87 	void (*pfunc)(char *);
     88 {
     89 	struct ifnet ifnet;
     90 	union {
     91 		struct ifaddr ifa;
     92 		struct in_ifaddr in;
     93 #ifdef INET6
     94 		struct in6_ifaddr in6;
     95 #endif /* INET6 */
     96 		struct ns_ifaddr ns;
     97 		struct iso_ifaddr iso;
     98 	} ifaddr;
     99 	u_long ifaddraddr;
    100 	struct sockaddr *sa;
    101 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
    102 	char name[IFNAMSIZ];
    103 #ifdef INET6
    104 	char hbuf[NI_MAXHOST];		/* for getnameinfo() */
    105 #ifdef KAME_SCOPEID
    106 	const int niflag = NI_NUMERICHOST | NI_WITHSCOPEID;
    107 #else
    108 	const int niflag = NI_NUMERICHOST;
    109 #endif
    110 #endif
    111 
    112 	if (ifnetaddr == 0) {
    113 		printf("ifnet: symbol not defined\n");
    114 		return;
    115 	}
    116 	if (interval) {
    117 		sidewaysintpr((unsigned)interval, ifnetaddr);
    118 		return;
    119 	}
    120 
    121 	/*
    122 	 * Find the pointer to the first ifnet structure.  Replace
    123 	 * the pointer to the TAILQ_HEAD with the actual pointer
    124 	 * to the first list element.
    125 	 */
    126 	if (kread(ifnetaddr, (char *)&ifhead, sizeof ifhead))
    127 		return;
    128 	ifnetaddr = (u_long)ifhead.tqh_first;
    129 
    130 	if (!sflag & !pflag) {
    131 		if (bflag) {
    132 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
    133 			       "%10.10s %10.10s",
    134 			       "Name", "Mtu", "Network", "Address",
    135 			       "Ibytes", "Obytes");
    136 		} else {
    137 			printf("%-5.5s %-5.5s %-13.13s %-17.17s "
    138 			       "%8.8s %5.5s %8.8s %5.5s %5.5s",
    139 			       "Name", "Mtu", "Network", "Address", "Ipkts", "Ierrs",
    140 			       "Opkts", "Oerrs", "Colls");
    141 		}
    142 		if (tflag)
    143 			printf(" %4.4s", "Time");
    144 		if (dflag)
    145 			printf(" %5.5s", "Drops");
    146 		putchar('\n');
    147 	}
    148 	ifaddraddr = 0;
    149 	while (ifnetaddr || ifaddraddr) {
    150 		struct sockaddr_in *sin;
    151 #ifdef INET6
    152 		struct sockaddr_in6 *sin6;
    153 #endif /* INET6 */
    154 		char *cp;
    155 		int n, m;
    156 
    157 		if (ifaddraddr == 0) {
    158 			if (kread(ifnetaddr, (char *)&ifnet, sizeof ifnet))
    159 				return;
    160 			memmove(name, ifnet.if_xname, IFNAMSIZ);
    161 			name[IFNAMSIZ - 1] = '\0';	/* sanity */
    162 			ifnetaddr = (u_long)ifnet.if_list.tqe_next;
    163 			if (interface != 0 && strcmp(name, interface) != 0)
    164 				continue;
    165 			cp = strchr(name, '\0');
    166 
    167 			if (pfunc) {
    168 				(*pfunc)(name);
    169 				continue;
    170 			}
    171 
    172 			if ((ifnet.if_flags & IFF_UP) == 0)
    173 				*cp++ = '*';
    174 			*cp = '\0';
    175 			ifaddraddr = (u_long)ifnet.if_addrlist.tqh_first;
    176 		}
    177 		printf("%-5.5s %-5llu ", name,
    178 		    (unsigned long long)ifnet.if_mtu);
    179 		if (ifaddraddr == 0) {
    180 			printf("%-13.13s ", "none");
    181 			printf("%-17.17s ", "none");
    182 		} else {
    183 			char hexsep = '.';		/* for hexprint */
    184 			const char *hexfmt = "%x%c";	/* for hexprint */
    185 			if (kread(ifaddraddr, (char *)&ifaddr, sizeof ifaddr)) {
    186 				ifaddraddr = 0;
    187 				continue;
    188 			}
    189 #define CP(x) ((char *)(x))
    190 			cp = (CP(ifaddr.ifa.ifa_addr) - CP(ifaddraddr)) +
    191 				CP(&ifaddr); sa = (struct sockaddr *)cp;
    192 			switch (sa->sa_family) {
    193 			case AF_UNSPEC:
    194 				printf("%-13.13s ", "none");
    195 				printf("%-17.17s ", "none");
    196 				break;
    197 			case AF_INET:
    198 				sin = (struct sockaddr_in *)sa;
    199 #ifdef notdef
    200 				/*
    201 				 * can't use inet_makeaddr because kernel
    202 				 * keeps nets unshifted.
    203 				 */
    204 				in = inet_makeaddr(ifaddr.in.ia_subnet,
    205 					INADDR_ANY);
    206 				cp = netname(in.s_addr,
    207 					ifaddr.in.ia_subnetmask);
    208 #else
    209 				cp = netname(ifaddr.in.ia_subnet,
    210 					ifaddr.in.ia_subnetmask);
    211 #endif
    212 				if (vflag)
    213 					n = strlen(cp) < 13 ? 13 : strlen(cp);
    214 				else
    215 					n = 13;
    216 				printf("%-*.*s ", n, n, cp);
    217 				cp = routename(sin->sin_addr.s_addr);
    218 				if (vflag)
    219 					n = strlen(cp) < 17 ? 17 : strlen(cp);
    220 				else
    221 					n = 17;
    222 				printf("%-*.*s ", n, n, cp);
    223 				if (aflag) {
    224 					u_long multiaddr;
    225 					struct in_multi inm;
    226 
    227 					multiaddr = (u_long)
    228 					    ifaddr.in.ia_multiaddrs.lh_first;
    229 					while (multiaddr != 0) {
    230 						kread(multiaddr, (char *)&inm,
    231 						   sizeof inm);
    232 						printf("\n%25s %-17.17s ", "",
    233 						   routename(
    234 						      inm.inm_addr.s_addr));
    235 						multiaddr =
    236 						   (u_long)inm.inm_list.le_next;
    237 					}
    238 				}
    239 				break;
    240 #ifdef INET6
    241 			case AF_INET6:
    242 				sin6 = (struct sockaddr_in6 *)sa;
    243 #ifdef KAME_SCOPEID
    244 				if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr)) {
    245 					sin6->sin6_scope_id =
    246 						ntohs(*(u_int16_t *)
    247 						  &sin6->sin6_addr.s6_addr[2]);
    248 					/* too little width */
    249 					if (!vflag)
    250 						sin6->sin6_scope_id = 0;
    251 					sin6->sin6_addr.s6_addr[2] = 0;
    252 					sin6->sin6_addr.s6_addr[3] = 0;
    253 				}
    254 #endif
    255 				cp = netname6(&ifaddr.in6.ia_addr,
    256 					&ifaddr.in6.ia_prefixmask.sin6_addr);
    257 				if (vflag)
    258 					n = strlen(cp) < 13 ? 13 : strlen(cp);
    259 				else
    260 					n = 13;
    261 				printf("%-*.*s ", n, n, cp);
    262 				if (getnameinfo((struct sockaddr *)sin6,
    263 						sin6->sin6_len,
    264 						hbuf, sizeof(hbuf), NULL, 0,
    265 						niflag) != 0) {
    266 					cp = "?";
    267 				} else
    268 					cp = hbuf;
    269 				if (vflag)
    270 					n = strlen(cp) < 17 ? 17 : strlen(cp);
    271 				else
    272 					n = 17;
    273 				printf("%-*.*s ", n, n, cp);
    274 				if (aflag) {
    275 					u_long multiaddr;
    276 					struct in6_multi inm;
    277 
    278 					multiaddr = (u_long)
    279 					    ifaddr.in6.ia6_multiaddrs.lh_first;
    280 					while (multiaddr != 0) {
    281 						kread(multiaddr, (char *)&inm,
    282 						   sizeof inm);
    283 						inet_ntop(AF_INET6, &inm.in6m_addr,
    284 						    hbuf, sizeof(hbuf));
    285 						cp = hbuf;
    286 						if (vflag)
    287 						    n = strlen(cp) < 17
    288 							? 17 : strlen(cp);
    289 						else
    290 						    n = 17;
    291 						printf("\n%25s %-*.*s ", "",
    292 						    n, n, cp);
    293 						multiaddr =
    294 						   (u_long)inm.in6m_entry.le_next;
    295 					}
    296 				}
    297 				break;
    298 #endif /*INET6*/
    299 #ifndef SMALL
    300 			case AF_APPLETALK:
    301 				printf("atalk:%-7.7s ",
    302 				       atalk_print(sa,0x10));
    303 				printf("%-17.17s ", atalk_print(sa,0x0b));
    304 				break;
    305 			case AF_NS:
    306 				{
    307 				struct sockaddr_ns *sns =
    308 					(struct sockaddr_ns *)sa;
    309 				u_long net;
    310 				char netnum[8];
    311 
    312 				*(union ns_net *)&net = sns->sns_addr.x_net;
    313 				(void)sprintf(netnum, "%xH",
    314 				    (u_int32_t)ntohl(net));
    315 				upHex(netnum);
    316 				printf("ns:%-10s ", netnum);
    317 				printf("%-17.17s ",
    318 				    ns_phost((struct sockaddr *)sns));
    319 				}
    320 				break;
    321 #endif
    322 			case AF_LINK:
    323 				{
    324 				struct sockaddr_dl *sdl =
    325 					(struct sockaddr_dl *)sa;
    326 				    cp = (char *)LLADDR(sdl);
    327 				    if (sdl->sdl_type == IFT_FDDI
    328 					|| sdl->sdl_type == IFT_ETHER)
    329 					    hexsep = ':', hexfmt = "%02x%c";
    330 				    n = sdl->sdl_alen;
    331 				}
    332 				m = printf("%-13.13s ", "<Link>");
    333 				goto hexprint;
    334 			default:
    335 				m = printf("(%d)", sa->sa_family);
    336 				for (cp = sa->sa_len + (char *)sa;
    337 					--cp > sa->sa_data && (*cp == 0);) {}
    338 				n = cp - sa->sa_data + 1;
    339 				cp = sa->sa_data;
    340 			hexprint:
    341 				while (--n >= 0)
    342 					m += printf(hexfmt, *cp++ & 0xff,
    343 						    n > 0 ? hexsep : ' ');
    344 				m = 32 - m;
    345 				while (m-- > 0)
    346 					putchar(' ');
    347 				break;
    348 			}
    349 			ifaddraddr = (u_long)ifaddr.ifa.ifa_list.tqe_next;
    350 		}
    351 		if (bflag) {
    352 			printf("%10llu %10llu",
    353 				(unsigned long long)ifnet.if_ibytes,
    354 				(unsigned long long)ifnet.if_obytes);
    355 		} else {
    356 			printf("%8llu %5llu %8llu %5llu %5llu",
    357 				(unsigned long long)ifnet.if_ipackets,
    358 				(unsigned long long)ifnet.if_ierrors,
    359 				(unsigned long long)ifnet.if_opackets,
    360 				(unsigned long long)ifnet.if_oerrors,
    361 				(unsigned long long)ifnet.if_collisions);
    362 		}
    363 		if (tflag)
    364 			printf(" %4d", ifnet.if_timer);
    365 		if (dflag)
    366 			printf(" %5d", ifnet.if_snd.ifq_drops);
    367 		putchar('\n');
    368 	}
    369 }
    370 
    371 #define	MAXIF	100
    372 struct	iftot {
    373 	char	ift_name[IFNAMSIZ];	/* interface name */
    374 	u_long	ift_ip;			/* input packets */
    375 	u_long	ift_ib;			/* input bytes */
    376 	u_long	ift_ie;			/* input errors */
    377 	u_long	ift_op;			/* output packets */
    378 	u_long	ift_ob;			/* output bytes */
    379 	u_long	ift_oe;			/* output errors */
    380 	u_long	ift_co;			/* collisions */
    381 	int	ift_dr;			/* drops */
    382 } iftot[MAXIF];
    383 
    384 u_char	signalled;			/* set if alarm goes off "early" */
    385 
    386 /*
    387  * Print a running summary of interface statistics.
    388  * Repeat display every interval seconds, showing statistics
    389  * collected over that interval.  Assumes that interval is non-zero.
    390  * First line printed at top of screen is always cumulative.
    391  */
    392 static void
    393 sidewaysintpr(interval, off)
    394 	unsigned interval;
    395 	u_long off;
    396 {
    397 	struct ifnet ifnet;
    398 	u_long firstifnet;
    399 	struct iftot *ip, *total;
    400 	int line;
    401 	struct iftot *lastif, *sum, *interesting;
    402 	struct ifnet_head ifhead;	/* TAILQ_HEAD */
    403 	int oldmask;
    404 
    405 	/*
    406 	 * Find the pointer to the first ifnet structure.  Replace
    407 	 * the pointer to the TAILQ_HEAD with the actual pointer
    408 	 * to the first list element.
    409 	 */
    410 	if (kread(off, (char *)&ifhead, sizeof ifhead))
    411 		return;
    412 	firstifnet = (u_long)ifhead.tqh_first;
    413 
    414 	lastif = iftot;
    415 	sum = iftot + MAXIF - 1;
    416 	total = sum - 1;
    417 	interesting = (interface == NULL) ? iftot : NULL;
    418 	for (off = firstifnet, ip = iftot; off;) {
    419 		if (kread(off, (char *)&ifnet, sizeof ifnet))
    420 			break;
    421 		memset(ip->ift_name, 0, sizeof(ip->ift_name));
    422 		snprintf(ip->ift_name, IFNAMSIZ, "%s", ifnet.if_xname);
    423 		if (interface && strcmp(ifnet.if_xname, interface) == 0)
    424 			interesting = ip;
    425 		ip++;
    426 		if (ip >= iftot + MAXIF - 2)
    427 			break;
    428 		off = (u_long)ifnet.if_list.tqe_next;
    429 	}
    430 	if (interesting == NULL) {
    431 		fprintf(stderr, "%s: %s: unknown interface\n",
    432 		    __progname, interface);
    433 		exit(1);
    434 	}
    435 	lastif = ip;
    436 
    437 	(void)signal(SIGALRM, catchalarm);
    438 	signalled = NO;
    439 	(void)alarm(interval);
    440 banner:
    441 	if (bflag)
    442 		printf("%7.7s in %8.8s %6.6s out %5.5s",
    443 		    interesting->ift_name, " ",
    444 		    interesting->ift_name, " ");
    445 	else
    446 		printf("%5.5s in %5.5s%5.5s out %5.5s %5.5s",
    447 		    interesting->ift_name, " ",
    448 		    interesting->ift_name, " ", " ");
    449 	if (dflag)
    450 		printf(" %5.5s", " ");
    451 	if (lastif - iftot > 0) {
    452 		if (bflag)
    453 			printf("  %7.7s in %8.8s %6.6s out %5.5s",
    454 			    "total", " ", "total", " ");
    455 		else
    456 			printf("  %5.5s in %5.5s%5.5s out %5.5s %5.5s",
    457 			    "total", " ", "total", " ", " ");
    458 		if (dflag)
    459 			printf(" %5.5s", " ");
    460 	}
    461 	for (ip = iftot; ip < iftot + MAXIF; ip++) {
    462 		ip->ift_ip = 0;
    463 		ip->ift_ib = 0;
    464 		ip->ift_ie = 0;
    465 		ip->ift_op = 0;
    466 		ip->ift_ob = 0;
    467 		ip->ift_oe = 0;
    468 		ip->ift_co = 0;
    469 		ip->ift_dr = 0;
    470 	}
    471 	putchar('\n');
    472 	if (bflag)
    473 		printf("%10.10s %8.8s %10.10s %5.5s",
    474 		    "bytes", " ", "bytes", " ");
    475 	else
    476 		printf("%8.8s %5.5s %8.8s %5.5s %5.5s",
    477 		    "packets", "errs", "packets", "errs", "colls");
    478 	if (dflag)
    479 		printf(" %5.5s", "drops");
    480 	if (lastif - iftot > 0) {
    481 		if (bflag)
    482 			printf("  %10.10s %8.8s %10.10s %5.5s",
    483 			    "bytes", " ", "bytes", " ");
    484 		else
    485 			printf("  %8.8s %5.5s %8.8s %5.5s %5.5s",
    486 			    "packets", "errs", "packets", "errs", "colls");
    487 		if (dflag)
    488 			printf(" %5.5s", "drops");
    489 	}
    490 	putchar('\n');
    491 	fflush(stdout);
    492 	line = 0;
    493 loop:
    494 	sum->ift_ip = 0;
    495 	sum->ift_ib = 0;
    496 	sum->ift_ie = 0;
    497 	sum->ift_op = 0;
    498 	sum->ift_ob = 0;
    499 	sum->ift_oe = 0;
    500 	sum->ift_co = 0;
    501 	sum->ift_dr = 0;
    502 	for (off = firstifnet, ip = iftot; off && ip < lastif; ip++) {
    503 		if (kread(off, (char *)&ifnet, sizeof ifnet)) {
    504 			off = 0;
    505 			continue;
    506 		}
    507 		if (ip == interesting) {
    508 			if (bflag) {
    509 				printf("%10llu %8.8s %10llu %5.5s",
    510 				    (unsigned long long)(ifnet.if_ibytes -
    511 					ip->ift_ib), " ",
    512 				    (unsigned long long)(ifnet.if_obytes -
    513 					ip->ift_ob), " ");
    514 			} else {
    515 				printf("%8llu %5llu %8llu %5llu %5llu",
    516 				    (unsigned long long)
    517 					(ifnet.if_ipackets - ip->ift_ip),
    518 				    (unsigned long long)
    519 					(ifnet.if_ierrors - ip->ift_ie),
    520 				    (unsigned long long)
    521 					(ifnet.if_opackets - ip->ift_op),
    522 				    (unsigned long long)
    523 					(ifnet.if_oerrors - ip->ift_oe),
    524 				    (unsigned long long)
    525 					(ifnet.if_collisions - ip->ift_co));
    526 			}
    527 			if (dflag)
    528 				printf(" %5llu",
    529 				    (unsigned long long)
    530 					(ifnet.if_snd.ifq_drops - ip->ift_dr));
    531 		}
    532 		ip->ift_ip = ifnet.if_ipackets;
    533 		ip->ift_ib = ifnet.if_ibytes;
    534 		ip->ift_ie = ifnet.if_ierrors;
    535 		ip->ift_op = ifnet.if_opackets;
    536 		ip->ift_ob = ifnet.if_obytes;
    537 		ip->ift_oe = ifnet.if_oerrors;
    538 		ip->ift_co = ifnet.if_collisions;
    539 		ip->ift_dr = ifnet.if_snd.ifq_drops;
    540 		sum->ift_ip += ip->ift_ip;
    541 		sum->ift_ib += ip->ift_ib;
    542 		sum->ift_ie += ip->ift_ie;
    543 		sum->ift_op += ip->ift_op;
    544 		sum->ift_ob += ip->ift_ob;
    545 		sum->ift_oe += ip->ift_oe;
    546 		sum->ift_co += ip->ift_co;
    547 		sum->ift_dr += ip->ift_dr;
    548 		off = (u_long)ifnet.if_list.tqe_next;
    549 	}
    550 	if (lastif - iftot > 0) {
    551 		if (bflag) {
    552 			printf("  %10llu %8.8s %10llu %5.5s",
    553 			    (unsigned long long)
    554 				(sum->ift_ib - total->ift_ib), " ",
    555 			    (unsigned long long)
    556 				(sum->ift_ob - total->ift_ob), " ");
    557 		} else {
    558 			printf("  %8llu %5llu %8llu %5llu %5llu",
    559 			    (unsigned long long)
    560 				(sum->ift_ip - total->ift_ip),
    561 			    (unsigned long long)
    562 				(sum->ift_ie - total->ift_ie),
    563 			    (unsigned long long)
    564 				(sum->ift_op - total->ift_op),
    565 			    (unsigned long long)
    566 				(sum->ift_oe - total->ift_oe),
    567 			    (unsigned long long)
    568 				(sum->ift_co - total->ift_co));
    569 		}
    570 		if (dflag)
    571 			printf(" %5llu",
    572 			    (unsigned long long)(sum->ift_dr - total->ift_dr));
    573 	}
    574 	*total = *sum;
    575 	putchar('\n');
    576 	fflush(stdout);
    577 	line++;
    578 	oldmask = sigblock(sigmask(SIGALRM));
    579 	if (! signalled) {
    580 		sigpause(0);
    581 	}
    582 	sigsetmask(oldmask);
    583 	signalled = NO;
    584 	(void)alarm(interval);
    585 	if (line == 21)
    586 		goto banner;
    587 	goto loop;
    588 	/*NOTREACHED*/
    589 }
    590 
    591 /*
    592  * Called if an interval expires before sidewaysintpr has completed a loop.
    593  * Sets a flag to not wait for the alarm.
    594  */
    595 static void
    596 catchalarm(signo)
    597 	int signo;
    598 {
    599 
    600 	signalled = YES;
    601 }
    602