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1 /*
2  * ifstat.c	handy utility to read net interface statistics
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10  */
11 
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <unistd.h>
15 #include <fcntl.h>
16 #include <string.h>
17 #include <errno.h>
18 #include <time.h>
19 #include <sys/time.h>
20 #include <fnmatch.h>
21 #include <sys/file.h>
22 #include <sys/socket.h>
23 #include <sys/un.h>
24 #include <sys/poll.h>
25 #include <sys/wait.h>
26 #include <sys/stat.h>
27 #include <signal.h>
28 #include <math.h>
29 #include <getopt.h>
30 
31 #include <libnetlink.h>
32 #include <linux/if.h>
33 #include <linux/if_link.h>
34 
35 #include <SNAPSHOT.h>
36 
37 int dump_zeros = 0;
38 int reset_history = 0;
39 int ignore_history = 0;
40 int no_output = 0;
41 int no_update = 0;
42 int scan_interval = 0;
43 int time_constant = 0;
44 int show_errors = 0;
45 double W;
46 char **patterns;
47 int npatterns;
48 
49 char info_source[128];
50 int source_mismatch;
51 
52 #define MAXS (sizeof(struct rtnl_link_stats)/sizeof(__u32))
53 
54 struct ifstat_ent
55 {
56 	struct ifstat_ent	*next;
57 	char			*name;
58 	int			ifindex;
59 	unsigned long long	val[MAXS];
60 	double			rate[MAXS];
61 	__u32			ival[MAXS];
62 };
63 
64 struct ifstat_ent *kern_db;
65 struct ifstat_ent *hist_db;
66 
match(const char * id)67 static int match(const char *id)
68 {
69 	int i;
70 
71 	if (npatterns == 0)
72 		return 1;
73 
74 	for (i=0; i<npatterns; i++) {
75 		if (!fnmatch(patterns[i], id, 0))
76 			return 1;
77 	}
78 	return 0;
79 }
80 
get_nlmsg(const struct sockaddr_nl * who,struct nlmsghdr * m,void * arg)81 static int get_nlmsg(const struct sockaddr_nl *who,
82 		     struct nlmsghdr *m, void *arg)
83 {
84 	struct ifinfomsg *ifi = NLMSG_DATA(m);
85 	struct rtattr * tb[IFLA_MAX+1];
86 	int len = m->nlmsg_len;
87 	struct ifstat_ent *n;
88 	int i;
89 
90 	if (m->nlmsg_type != RTM_NEWLINK)
91 		return 0;
92 
93 	len -= NLMSG_LENGTH(sizeof(*ifi));
94 	if (len < 0)
95 		return -1;
96 
97 	if (!(ifi->ifi_flags&IFF_UP))
98 		return 0;
99 
100 	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
101 	if (tb[IFLA_IFNAME] == NULL || tb[IFLA_STATS] == NULL)
102 		return 0;
103 
104 	n = malloc(sizeof(*n));
105 	if (!n)
106 		abort();
107 	n->ifindex = ifi->ifi_index;
108 	n->name = strdup(RTA_DATA(tb[IFLA_IFNAME]));
109 	memcpy(&n->ival, RTA_DATA(tb[IFLA_STATS]), sizeof(n->ival));
110 	memset(&n->rate, 0, sizeof(n->rate));
111 	for (i=0; i<MAXS; i++)
112 		n->val[i] = n->ival[i];
113 	n->next = kern_db;
114 	kern_db = n;
115 	return 0;
116 }
117 
load_info(void)118 void load_info(void)
119 {
120 	struct ifstat_ent *db, *n;
121 	struct rtnl_handle rth;
122 
123 	if (rtnl_open(&rth, 0) < 0)
124 		exit(1);
125 
126 	if (rtnl_wilddump_request(&rth, AF_INET, RTM_GETLINK) < 0) {
127 		perror("Cannot send dump request");
128 		exit(1);
129 	}
130 
131 	if (rtnl_dump_filter(&rth, get_nlmsg, NULL) < 0) {
132 		fprintf(stderr, "Dump terminated\n");
133 		exit(1);
134 	}
135 
136 	rtnl_close(&rth);
137 
138 	db = kern_db;
139 	kern_db = NULL;
140 
141 	while (db) {
142 		n = db;
143 		db = db->next;
144 		n->next = kern_db;
145 		kern_db = n;
146 	}
147 }
148 
load_raw_table(FILE * fp)149 void load_raw_table(FILE *fp)
150 {
151 	char buf[4096];
152 	struct ifstat_ent *db = NULL;
153 	struct ifstat_ent *n;
154 
155 	while (fgets(buf, sizeof(buf), fp) != NULL) {
156 		char *p;
157 		char *next;
158 		int i;
159 
160 		if (buf[0] == '#') {
161 			buf[strlen(buf)-1] = 0;
162 			if (info_source[0] && strcmp(info_source, buf+1))
163 				source_mismatch = 1;
164 			strncpy(info_source, buf+1, sizeof(info_source)-1);
165 			continue;
166 		}
167 		if ((n = malloc(sizeof(*n))) == NULL)
168 			abort();
169 
170 		if (!(p = strchr(buf, ' ')))
171 			abort();
172 		*p++ = 0;
173 
174 		if (sscanf(buf, "%d", &n->ifindex) != 1)
175 			abort();
176 		if (!(next = strchr(p, ' ')))
177 			abort();
178 		*next++ = 0;
179 
180 		n->name = strdup(p);
181 		p = next;
182 
183 		for (i=0; i<MAXS; i++) {
184 			unsigned rate;
185 			if (!(next = strchr(p, ' ')))
186 				abort();
187 			*next++ = 0;
188 			if (sscanf(p, "%llu", n->val+i) != 1)
189 				abort();
190 			n->ival[i] = (__u32)n->val[i];
191 			p = next;
192 			if (!(next = strchr(p, ' ')))
193 				abort();
194 			*next++ = 0;
195 			if (sscanf(p, "%u", &rate) != 1)
196 				abort();
197 			n->rate[i] = rate;
198 			p = next;
199 		}
200 		n->next = db;
201 		db = n;
202 	}
203 
204 	while (db) {
205 		n = db;
206 		db = db->next;
207 		n->next = kern_db;
208 		kern_db = n;
209 	}
210 }
211 
dump_raw_db(FILE * fp,int to_hist)212 void dump_raw_db(FILE *fp, int to_hist)
213 {
214 	struct ifstat_ent *n, *h;
215 	h = hist_db;
216 	fprintf(fp, "#%s\n", info_source);
217 
218 	for (n=kern_db; n; n=n->next) {
219 		int i;
220 		unsigned long long *vals = n->val;
221 		double *rates = n->rate;
222 		if (!match(n->name)) {
223 			struct ifstat_ent *h1;
224 			if (!to_hist)
225 				continue;
226 			for (h1 = h; h1; h1 = h1->next) {
227 				if (h1->ifindex == n->ifindex) {
228 					vals = h1->val;
229 					rates = h1->rate;
230 					h = h1->next;
231 					break;
232 				}
233 			}
234 		}
235 		fprintf(fp, "%d %s ", n->ifindex, n->name);
236 		for (i=0; i<MAXS; i++)
237 			fprintf(fp, "%llu %u ", vals[i], (unsigned)rates[i]);
238 		fprintf(fp, "\n");
239 	}
240 }
241 
242 /* use communication definitions of meg/kilo etc */
243 static const unsigned long long giga = 1000000000ull;
244 static const unsigned long long mega = 1000000;
245 static const unsigned long long kilo = 1000;
246 
format_rate(FILE * fp,unsigned long long * vals,double * rates,int i)247 void format_rate(FILE *fp, unsigned long long *vals, double *rates, int i)
248 {
249 	char temp[64];
250 	if (vals[i] > giga)
251 		fprintf(fp, "%7lluM ", vals[i]/mega);
252 	else if (vals[i] > mega)
253 		fprintf(fp, "%7lluK ", vals[i]/kilo);
254 	else
255 		fprintf(fp, "%8llu ", vals[i]);
256 
257 	if (rates[i] > mega) {
258 		sprintf(temp, "%uM", (unsigned)(rates[i]/mega));
259 		fprintf(fp, "%-6s ", temp);
260 	} else if (rates[i] > kilo) {
261 		sprintf(temp, "%uK", (unsigned)(rates[i]/kilo));
262 		fprintf(fp, "%-6s ", temp);
263 	} else
264 		fprintf(fp, "%-6u ", (unsigned)rates[i]);
265 }
266 
format_pair(FILE * fp,unsigned long long * vals,int i,int k)267 void format_pair(FILE *fp, unsigned long long *vals, int i, int k)
268 {
269 	char temp[64];
270 	if (vals[i] > giga)
271 		fprintf(fp, "%7lluM ", vals[i]/mega);
272 	else if (vals[i] > mega)
273 		fprintf(fp, "%7lluK ", vals[i]/kilo);
274 	else
275 		fprintf(fp, "%8llu ", vals[i]);
276 
277 	if (vals[k] > giga) {
278 		sprintf(temp, "%uM", (unsigned)(vals[k]/mega));
279 		fprintf(fp, "%-6s ", temp);
280 	} else if (vals[k] > mega) {
281 		sprintf(temp, "%uK", (unsigned)(vals[k]/kilo));
282 		fprintf(fp, "%-6s ", temp);
283 	} else
284 		fprintf(fp, "%-6u ", (unsigned)vals[k]);
285 }
286 
print_head(FILE * fp)287 void print_head(FILE *fp)
288 {
289 	fprintf(fp, "#%s\n", info_source);
290 	fprintf(fp, "%-15s ", "Interface");
291 
292 	fprintf(fp, "%8s/%-6s ", "RX Pkts", "Rate");
293 	fprintf(fp, "%8s/%-6s ", "TX Pkts", "Rate");
294 	fprintf(fp, "%8s/%-6s ", "RX Data", "Rate");
295 	fprintf(fp, "%8s/%-6s\n","TX Data", "Rate");
296 
297 	if (!show_errors) {
298 		fprintf(fp, "%-15s ", "");
299 		fprintf(fp, "%8s/%-6s ", "RX Errs", "Drop");
300 		fprintf(fp, "%8s/%-6s ", "TX Errs", "Drop");
301 		fprintf(fp, "%8s/%-6s ", "RX Over", "Rate");
302 		fprintf(fp, "%8s/%-6s\n","TX Coll", "Rate");
303 	} else {
304 		fprintf(fp, "%-15s ", "");
305 		fprintf(fp, "%8s/%-6s ", "RX Errs", "Rate");
306 		fprintf(fp, "%8s/%-6s ", "RX Drop", "Rate");
307 		fprintf(fp, "%8s/%-6s ", "RX Over", "Rate");
308 		fprintf(fp, "%8s/%-6s\n","RX Leng", "Rate");
309 
310 		fprintf(fp, "%-15s ", "");
311 		fprintf(fp, "%8s/%-6s ", "RX Crc", "Rate");
312 		fprintf(fp, "%8s/%-6s ", "RX Frm", "Rate");
313 		fprintf(fp, "%8s/%-6s ", "RX Fifo", "Rate");
314 		fprintf(fp, "%8s/%-6s\n","RX Miss", "Rate");
315 
316 		fprintf(fp, "%-15s ", "");
317 		fprintf(fp, "%8s/%-6s ", "TX Errs", "Rate");
318 		fprintf(fp, "%8s/%-6s ", "TX Drop", "Rate");
319 		fprintf(fp, "%8s/%-6s ", "TX Coll", "Rate");
320 		fprintf(fp, "%8s/%-6s\n","TX Carr", "Rate");
321 
322 		fprintf(fp, "%-15s ", "");
323 		fprintf(fp, "%8s/%-6s ", "TX Abrt", "Rate");
324 		fprintf(fp, "%8s/%-6s ", "TX Fifo", "Rate");
325 		fprintf(fp, "%8s/%-6s ", "TX Hear", "Rate");
326 		fprintf(fp, "%8s/%-6s\n","TX Wind", "Rate");
327 	}
328 }
329 
print_one_if(FILE * fp,struct ifstat_ent * n,unsigned long long * vals)330 void print_one_if(FILE *fp, struct ifstat_ent *n, unsigned long long *vals)
331 {
332 	int i;
333 	fprintf(fp, "%-15s ", n->name);
334 	for (i=0; i<4; i++)
335 		format_rate(fp, vals, n->rate, i);
336 	fprintf(fp, "\n");
337 
338 	if (!show_errors) {
339 		fprintf(fp, "%-15s ", "");
340 		format_pair(fp, vals, 4, 6);
341 		format_pair(fp, vals, 5, 7);
342 		format_rate(fp, vals, n->rate, 11);
343 		format_rate(fp, vals, n->rate, 9);
344 		fprintf(fp, "\n");
345 	} else {
346 		fprintf(fp, "%-15s ", "");
347 		format_rate(fp, vals, n->rate, 4);
348 		format_rate(fp, vals, n->rate, 6);
349 		format_rate(fp, vals, n->rate, 11);
350 		format_rate(fp, vals, n->rate, 10);
351 		fprintf(fp, "\n");
352 
353 		fprintf(fp, "%-15s ", "");
354 		format_rate(fp, vals, n->rate, 12);
355 		format_rate(fp, vals, n->rate, 13);
356 		format_rate(fp, vals, n->rate, 14);
357 		format_rate(fp, vals, n->rate, 15);
358 		fprintf(fp, "\n");
359 
360 		fprintf(fp, "%-15s ", "");
361 		format_rate(fp, vals, n->rate, 5);
362 		format_rate(fp, vals, n->rate, 7);
363 		format_rate(fp, vals, n->rate, 9);
364 		format_rate(fp, vals, n->rate, 17);
365 		fprintf(fp, "\n");
366 
367 		fprintf(fp, "%-15s ", "");
368 		format_rate(fp, vals, n->rate, 16);
369 		format_rate(fp, vals, n->rate, 18);
370 		format_rate(fp, vals, n->rate, 19);
371 		format_rate(fp, vals, n->rate, 20);
372 		fprintf(fp, "\n");
373 	}
374 }
375 
376 
dump_kern_db(FILE * fp)377 void dump_kern_db(FILE *fp)
378 {
379 	struct ifstat_ent *n;
380 
381 	print_head(fp);
382 
383 	for (n=kern_db; n; n=n->next) {
384 		if (!match(n->name))
385 			continue;
386 		print_one_if(fp, n, n->val);
387 	}
388 }
389 
390 
dump_incr_db(FILE * fp)391 void dump_incr_db(FILE *fp)
392 {
393 	struct ifstat_ent *n, *h;
394 	h = hist_db;
395 
396 	print_head(fp);
397 
398 	for (n=kern_db; n; n=n->next) {
399 		int i;
400 		unsigned long long vals[MAXS];
401 		struct ifstat_ent *h1;
402 
403 		memcpy(vals, n->val, sizeof(vals));
404 
405 		for (h1 = h; h1; h1 = h1->next) {
406 			if (h1->ifindex == n->ifindex) {
407 				for (i = 0; i < MAXS; i++)
408 					vals[i] -= h1->val[i];
409 				h = h1->next;
410 				break;
411 			}
412 		}
413 		if (!match(n->name))
414 			continue;
415 		print_one_if(fp, n, vals);
416 	}
417 }
418 
419 
420 static int children;
421 
sigchild(int signo)422 void sigchild(int signo)
423 {
424 }
425 
update_db(int interval)426 void update_db(int interval)
427 {
428 	struct ifstat_ent *n, *h;
429 
430 	n = kern_db;
431 	kern_db = NULL;
432 
433 	load_info();
434 
435 	h = kern_db;
436 	kern_db = n;
437 
438 	for (n = kern_db; n; n = n->next) {
439 		struct ifstat_ent *h1;
440 		for (h1 = h; h1; h1 = h1->next) {
441 			if (h1->ifindex == n->ifindex) {
442 				int i;
443 				for (i = 0; i < MAXS; i++) {
444 					if ((long)(h1->ival[i] - n->ival[i]) < 0) {
445 						memset(n->ival, 0, sizeof(n->ival));
446 						break;
447 					}
448 				}
449 				for (i = 0; i < MAXS; i++) {
450 					double sample;
451 					unsigned long incr = h1->ival[i] - n->ival[i];
452 					n->val[i] += incr;
453 					n->ival[i] = h1->ival[i];
454 					sample = (double)(incr*1000)/interval;
455 					if (interval >= scan_interval) {
456 						n->rate[i] += W*(sample-n->rate[i]);
457 					} else if (interval >= 1000) {
458 						if (interval >= time_constant) {
459 							n->rate[i] = sample;
460 						} else {
461 							double w = W*(double)interval/scan_interval;
462 							n->rate[i] += w*(sample-n->rate[i]);
463 						}
464 					}
465 				}
466 
467 				while (h != h1) {
468 					struct ifstat_ent *tmp = h;
469 					h = h->next;
470 					free(tmp->name);
471 					free(tmp);
472 				};
473 				h = h1->next;
474 				free(h1->name);
475 				free(h1);
476 				break;
477 			}
478 		}
479 	}
480 }
481 
482 #define T_DIFF(a,b) (((a).tv_sec-(b).tv_sec)*1000 + ((a).tv_usec-(b).tv_usec)/1000)
483 
484 
server_loop(int fd)485 void server_loop(int fd)
486 {
487 	struct timeval snaptime = { 0 };
488 	struct pollfd p;
489 	p.fd = fd;
490 	p.events = p.revents = POLLIN;
491 
492 	sprintf(info_source, "%d.%lu sampling_interval=%d time_const=%d",
493 		getpid(), (unsigned long)random(), scan_interval/1000, time_constant/1000);
494 
495 	load_info();
496 
497 	for (;;) {
498 		int status;
499 		int tdiff;
500 		struct timeval now;
501 
502 		gettimeofday(&now, NULL);
503 		tdiff = T_DIFF(now, snaptime);
504 		if (tdiff >= scan_interval) {
505 			update_db(tdiff);
506 			snaptime = now;
507 			tdiff = 0;
508 		}
509 
510 		if (poll(&p, 1, tdiff + scan_interval) > 0
511 		    && (p.revents&POLLIN)) {
512 			int clnt = accept(fd, NULL, NULL);
513 			if (clnt >= 0) {
514 				pid_t pid;
515 				if (children >= 5) {
516 					close(clnt);
517 				} else if ((pid = fork()) != 0) {
518 					if (pid>0)
519 						children++;
520 					close(clnt);
521 				} else {
522 					FILE *fp = fdopen(clnt, "w");
523 					if (fp) {
524 						if (tdiff > 0)
525 							update_db(tdiff);
526 						dump_raw_db(fp, 0);
527 					}
528 					exit(0);
529 				}
530 			}
531 		}
532 		while (children && waitpid(-1, &status, WNOHANG) > 0)
533 			children--;
534 	}
535 }
536 
verify_forging(int fd)537 int verify_forging(int fd)
538 {
539 	struct ucred cred;
540 	socklen_t olen = sizeof(cred);
541 
542 	if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void*)&cred, &olen) ||
543 	    olen < sizeof(cred))
544 		return -1;
545 	if (cred.uid == getuid() || cred.uid == 0)
546 		return 0;
547 	return -1;
548 }
549 
550 static void usage(void) __attribute__((noreturn));
551 
usage(void)552 static void usage(void)
553 {
554 	fprintf(stderr,
555 "Usage: ifstat [OPTION] [ PATTERN [ PATTERN ] ]\n"
556 "   -h, --help		this message\n"
557 "   -a, --ignore	ignore history\n"
558 "   -d, --scan=SECS	sample every statistics every SECS\n"
559 "   -e, --errors	show errors\n"
560 "   -n, --nooutput	do history only\n"
561 "   -r, --reset		reset history\n"
562 "   -s, --noupdate	don;t update history\n"
563 "   -t, --interval=SECS	report average over the last SECS\n"
564 "   -V, --version	output version information\n"
565 "   -z, --zeros		show entries with zero activity\n");
566 
567 	exit(-1);
568 }
569 
570 static const struct option longopts[] = {
571 	{ "help", 0, 0, 'h' },
572 	{ "ignore",  0,  0, 'a' },
573 	{ "scan", 1, 0, 'd'},
574 	{ "errors", 0, 0, 'e' },
575 	{ "nooutput", 0, 0, 'n' },
576 	{ "reset", 0, 0, 'r' },
577 	{ "noupdate", 0, 0, 's' },
578 	{ "interval", 1, 0, 't' },
579 	{ "version", 0, 0, 'V' },
580 	{ "zeros", 0, 0, 'z' },
581 	{ 0 }
582 };
583 
main(int argc,char * argv[])584 int main(int argc, char *argv[])
585 {
586 	char hist_name[128];
587 	struct sockaddr_un sun;
588 	FILE *hist_fp = NULL;
589 	int ch;
590 	int fd;
591 
592 	while ((ch = getopt_long(argc, argv, "hvVzrnasd:t:eK",
593 			longopts, NULL)) != EOF) {
594 		switch(ch) {
595 		case 'z':
596 			dump_zeros = 1;
597 			break;
598 		case 'r':
599 			reset_history = 1;
600 			break;
601 		case 'a':
602 			ignore_history = 1;
603 			break;
604 		case 's':
605 			no_update = 1;
606 			break;
607 		case 'n':
608 			no_output = 1;
609 			break;
610 		case 'e':
611 			show_errors = 1;
612 			break;
613 		case 'd':
614 			scan_interval = atoi(optarg) * 1000;
615 			if (scan_interval <= 0) {
616 				fprintf(stderr, "ifstat: invalid scan interval\n");
617 				exit(-1);
618 			}
619 			break;
620 		case 't':
621 			time_constant = atoi(optarg);
622 			if (time_constant <= 0) {
623 				fprintf(stderr, "ifstat: invalid time constant divisor\n");
624 				exit(-1);
625 			}
626 			break;
627 		case 'v':
628 		case 'V':
629 			printf("ifstat utility, iproute2-ss%s\n", SNAPSHOT);
630 			exit(0);
631 		case 'h':
632 		case '?':
633 		default:
634 			usage();
635 		}
636 	}
637 
638 	argc -= optind;
639 	argv += optind;
640 
641 	sun.sun_family = AF_UNIX;
642 	sun.sun_path[0] = 0;
643 	sprintf(sun.sun_path+1, "ifstat%d", getuid());
644 
645 	if (scan_interval > 0) {
646 		if (time_constant == 0)
647 			time_constant = 60;
648 		time_constant *= 1000;
649 		W = 1 - 1/exp(log(10)*(double)scan_interval/time_constant);
650 		if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
651 			perror("ifstat: socket");
652 			exit(-1);
653 		}
654 		if (bind(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {
655 			perror("ifstat: bind");
656 			exit(-1);
657 		}
658 		if (listen(fd, 5) < 0) {
659 			perror("ifstat: listen");
660 			exit(-1);
661 		}
662 		if (daemon(0, 0)) {
663 			perror("ifstat: daemon");
664 			exit(-1);
665 		}
666 		signal(SIGPIPE, SIG_IGN);
667 		signal(SIGCHLD, sigchild);
668 		server_loop(fd);
669 		exit(0);
670 	}
671 
672 	patterns = argv;
673 	npatterns = argc;
674 
675 	if (getenv("IFSTAT_HISTORY"))
676 		snprintf(hist_name, sizeof(hist_name),
677 			 "%s", getenv("IFSTAT_HISTORY"));
678 	else
679 		snprintf(hist_name, sizeof(hist_name),
680 			 "%s/.ifstat.u%d", P_tmpdir, getuid());
681 
682 	if (reset_history)
683 		unlink(hist_name);
684 
685 	if (!ignore_history || !no_update) {
686 		struct stat stb;
687 
688 		fd = open(hist_name, O_RDWR|O_CREAT|O_NOFOLLOW, 0600);
689 		if (fd < 0) {
690 			perror("ifstat: open history file");
691 			exit(-1);
692 		}
693 		if ((hist_fp = fdopen(fd, "r+")) == NULL) {
694 			perror("ifstat: fdopen history file");
695 			exit(-1);
696 		}
697 		if (flock(fileno(hist_fp), LOCK_EX)) {
698 			perror("ifstat: flock history file");
699 			exit(-1);
700 		}
701 		if (fstat(fileno(hist_fp), &stb) != 0) {
702 			perror("ifstat: fstat history file");
703 			exit(-1);
704 		}
705 		if (stb.st_nlink != 1 || stb.st_uid != getuid()) {
706 			fprintf(stderr, "ifstat: something is so wrong with history file, that I prefer not to proceed.\n");
707 			exit(-1);
708 		}
709 		if (!ignore_history) {
710 			FILE *tfp;
711 			long uptime = -1;
712 			if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
713 				if (fscanf(tfp, "%ld", &uptime) != 1)
714 					uptime = -1;
715 				fclose(tfp);
716 			}
717 			if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
718 				fprintf(stderr, "ifstat: history is aged out, resetting\n");
719 				ftruncate(fileno(hist_fp), 0);
720 			}
721 		}
722 
723 		load_raw_table(hist_fp);
724 
725 		hist_db = kern_db;
726 		kern_db = NULL;
727 	}
728 
729 	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
730 	    (connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0
731 	     || (strcpy(sun.sun_path+1, "ifstat0"),
732 		 connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
733 	    && verify_forging(fd) == 0) {
734 		FILE *sfp = fdopen(fd, "r");
735 		load_raw_table(sfp);
736 		if (hist_db && source_mismatch) {
737 			fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
738 			hist_db = NULL;
739 		}
740 		fclose(sfp);
741 	} else {
742 		if (fd >= 0)
743 			close(fd);
744 		if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
745 			fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
746 			hist_db = NULL;
747 			info_source[0] = 0;
748 		}
749 		load_info();
750 		if (info_source[0] == 0)
751 			strcpy(info_source, "kernel");
752 	}
753 
754 	if (!no_output) {
755 		if (ignore_history || hist_db == NULL)
756 			dump_kern_db(stdout);
757 		else
758 			dump_incr_db(stdout);
759 	}
760 	if (!no_update) {
761 		ftruncate(fileno(hist_fp), 0);
762 		rewind(hist_fp);
763 		dump_raw_db(hist_fp, 1);
764 		fflush(hist_fp);
765 	}
766 	exit(0);
767 }
768