misc/ifstat.c

   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
  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
  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
 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, NULL, 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
 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
 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
 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
 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
 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
 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
 377 void dump_kern_db(FILE *fp)
 378 {
 379         struct ifstat_ent *n, *h;
 380         h = hist_db;
 381
 382         print_head(fp);
 383
 384         for (n=kern_db; n; n=n->next) {
 385                 if (!match(n->name))
 386                         continue;
 387                 print_one_if(fp, n, n->val);
 388         }
 389 }
 390
 391
 392 void dump_incr_db(FILE *fp)
 393 {
 394         struct ifstat_ent *n, *h;
 395         h = hist_db;
 396
 397         print_head(fp);
 398
 399         for (n=kern_db; n; n=n->next) {
 400                 int i;
 401                 unsigned long long vals[MAXS];
 402                 struct ifstat_ent *h1;
 403
 404                 memcpy(vals, n->val, sizeof(vals));
 405
 406                 for (h1 = h; h1; h1 = h1->next) {
 407                         if (h1->ifindex == n->ifindex) {
 408                                 for (i = 0; i < MAXS; i++)
 409                                         vals[i] -= h1->val[i];
 410                                 h = h1->next;
 411                                 break;
 412                         }
 413                 }
 414                 if (!match(n->name))
 415                         continue;
 416                 print_one_if(fp, n, vals);
 417         }
 418 }
 419
 420
 421 static int children;
 422
 423 void sigchild(int signo)
 424 {
 425 }
 426
 427 void update_db(int interval)
 428 {
 429         struct ifstat_ent *n, *h;
 430
 431         n = kern_db;
 432         kern_db = NULL;
 433
 434         load_info();
 435
 436         h = kern_db;
 437         kern_db = n;
 438
 439         for (n = kern_db; n; n = n->next) {
 440                 struct ifstat_ent *h1;
 441                 for (h1 = h; h1; h1 = h1->next) {
 442                         if (h1->ifindex == n->ifindex) {
 443                                 int i;
 444                                 for (i = 0; i < MAXS; i++) {
 445                                         if ((long)(h1->ival[i] - n->ival[i]) < 0) {
 446                                                 memset(n->ival, 0, sizeof(n->ival));
 447                                                 break;
 448                                         }
 449                                 }
 450                                 for (i = 0; i < MAXS; i++) {
 451                                         double sample;
 452                                         unsigned long incr = h1->ival[i] - n->ival[i];
 453                                         n->val[i] += incr;
 454                                         n->ival[i] = h1->ival[i];
 455                                         sample = (double)(incr*1000)/interval;
 456                                         if (interval >= scan_interval) {
 457                                                 n->rate[i] += W*(sample-n->rate[i]);
 458                                         } else if (interval >= 1000) {
 459                                                 if (interval >= time_constant) {
 460                                                         n->rate[i] = sample;
 461                                                 } else {
 462                                                         double w = W*(double)interval/scan_interval;
 463                                                         n->rate[i] += w*(sample-n->rate[i]);
 464                                                 }
 465                                         }
 466                                 }
 467
 468                                 while (h != h1) {
 469                                         struct ifstat_ent *tmp = h;
 470                                         h = h->next;
 471                                         free(tmp->name);
 472                                         free(tmp);
 473                                 };
 474                                 h = h1->next;
 475                                 free(h1->name);
 476                                 free(h1);
 477                                 break;
 478                         }
 479                 }
 480         }
 481 }
 482
 483 #define T_DIFF(a,b) (((a).tv_sec-(b).tv_sec)*1000 + ((a).tv_usec-(b).tv_usec)/1000)
 484
 485
 486 void server_loop(int fd)
 487 {
 488         struct timeval snaptime = { 0 };
 489         struct pollfd p;
 490         p.fd = fd;
 491         p.events = p.revents = POLLIN;
 492
 493         sprintf(info_source, "%d.%lu sampling_interval=%d time_const=%d",
 494                 getpid(), (unsigned long)random(), scan_interval/1000, time_constant/1000);
 495
 496         load_info();
 497
 498         for (;;) {
 499                 int status;
 500                 int tdiff;
 501                 struct timeval now;
 502
 503                 gettimeofday(&now, NULL);
 504                 tdiff = T_DIFF(now, snaptime);
 505                 if (tdiff >= scan_interval) {
 506                         update_db(tdiff);
 507                         snaptime = now;
 508                         tdiff = 0;
 509                 }
 510
 511                 if (poll(&p, 1, tdiff + scan_interval) > 0
 512                     && (p.revents&POLLIN)) {
 513                         int clnt = accept(fd, NULL, NULL);
 514                         if (clnt >= 0) {
 515                                 pid_t pid;
 516                                 if (children >= 5) {
 517                                         close(clnt);
 518                                 } else if ((pid = fork()) != 0) {
 519                                         if (pid>0)
 520                                                 children++;
 521                                         close(clnt);
 522                                 } else {
 523                                         FILE *fp = fdopen(clnt, "w");
 524                                         if (fp) {
 525                                                 if (tdiff > 0)
 526                                                         update_db(tdiff);
 527                                                 dump_raw_db(fp, 0);
 528                                         }
 529                                         exit(0);
 530                                 }
 531                         }
 532                 }
 533                 while (children && waitpid(-1, &status, WNOHANG) > 0)
 534                         children--;
 535         }
 536 }
 537
 538 int verify_forging(int fd)
 539 {
 540         struct ucred cred;
 541         socklen_t olen = sizeof(cred);
 542
 543         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void*)&cred, &olen) ||
 544             olen < sizeof(cred))
 545                 return -1;
 546         if (cred.uid == getuid() || cred.uid == 0)
 547                 return 0;
 548         return -1;
 549 }
 550
 551 static void usage(void) __attribute__((noreturn));
 552
 553 static void usage(void)
 554 {
 555         fprintf(stderr,
 556 "Usage: ifstat [OPTION] [ PATTERN [ PATTERN ] ]\n"
 557 "   -h, --help          this message\n"
 558 "   -a, --ignore        ignore history\n"
 559 "   -d, --scan=SECS     sample every statistics every SECS\n"
 560 "   -e, --errors        show errors\n"
 561 "   -n, --nooutput      do history only\n"
 562 "   -r, --reset         reset history\n"
 563 "   -s, --noupdate      don;t update history\n"
 564 "   -t, --interval=SECS report average over the last SECS\n"
 565 "   -V, --version       output version information\n"
 566 "   -z, --zeros         show entries with zero activity\n");
 567
 568         exit(-1);
 569 }
 570
 571 static const struct option longopts[] = {
 572         { "help", 0, 0, 'h' },
 573         { "ignore",  0,  0, 'a' },
 574         { "scan", 1, 0, 'd'},
 575         { "errors", 0, 0, 'e' },
 576         { "nooutput", 0, 0, 'n' },
 577         { "reset", 0, 0, 'r' },
 578         { "noupdate", 0, 0, 's' },
 579         { "interval", 1, 0, 't' },
 580         { "version", 0, 0, 'V' },
 581         { "zeros", 0, 0, 'z' },
 582         { 0 }
 583 };
 584
 585 int main(int argc, char *argv[])
 586 {
 587         char hist_name[128];
 588         struct sockaddr_un sun;
 589         FILE *hist_fp = NULL;
 590         int ch;
 591         int fd;
 592
 593         while ((ch = getopt_long(argc, argv, "hvVzrnasd:t:eK",
 594                         longopts, NULL)) != EOF) {
 595                 switch(ch) {
 596                 case 'z':
 597                         dump_zeros = 1;
 598                         break;
 599                 case 'r':
 600                         reset_history = 1;
 601                         break;
 602                 case 'a':
 603                         ignore_history = 1;
 604                         break;
 605                 case 's':
 606                         no_update = 1;
 607                         break;
 608                 case 'n':
 609                         no_output = 1;
 610                         break;
 611                 case 'e':
 612                         show_errors = 1;
 613                         break;
 614                 case 'd':
 615                         scan_interval = atoi(optarg) * 1000;
 616                         if (scan_interval <= 0) {
 617                                 fprintf(stderr, "ifstat: invalid scan interval\n");
 618                                 exit(-1);
 619                         }
 620                         break;
 621                 case 't':
 622                         time_constant = atoi(optarg);
 623                         if (time_constant <= 0) {
 624                                 fprintf(stderr, "ifstat: invalid time constant divisor\n");
 625                                 exit(-1);
 626                         }
 627                         break;
 628                 case 'v':
 629                 case 'V':
 630                         printf("ifstat utility, iproute2-ss%s\n", SNAPSHOT);
 631                         exit(0);
 632                 case 'h':
 633                 case '?':
 634                 default:
 635                         usage();
 636                 }
 637         }
 638
 639         argc -= optind;
 640         argv += optind;
 641
 642         sun.sun_family = AF_UNIX;
 643         sun.sun_path[0] = 0;
 644         sprintf(sun.sun_path+1, "ifstat%d", getuid());
 645
 646         if (scan_interval > 0) {
 647                 if (time_constant == 0)
 648                         time_constant = 60;
 649                 time_constant *= 1000;
 650                 W = 1 - 1/exp(log(10)*(double)scan_interval/time_constant);
 651                 if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) {
 652                         perror("ifstat: socket");
 653                         exit(-1);
 654                 }
 655                 if (bind(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) < 0) {
 656                         perror("ifstat: bind");
 657                         exit(-1);
 658                 }
 659                 if (listen(fd, 5) < 0) {
 660                         perror("ifstat: listen");
 661                         exit(-1);
 662                 }
 663                 if (daemon(0, 0)) {
 664                         perror("ifstat: daemon");
 665                         exit(-1);
 666                 }
 667                 signal(SIGPIPE, SIG_IGN);
 668                 signal(SIGCHLD, sigchild);
 669                 server_loop(fd);
 670                 exit(0);
 671         }
 672
 673         patterns = argv;
 674         npatterns = argc;
 675
 676         if (getenv("IFSTAT_HISTORY"))
 677                 snprintf(hist_name, sizeof(hist_name),
 678                          "%s", getenv("IFSTAT_HISTORY"));
 679         else
 680                 snprintf(hist_name, sizeof(hist_name),
 681                          "%s/.ifstat.u%d", P_tmpdir, getuid());
 682
 683         if (reset_history)
 684                 unlink(hist_name);
 685
 686         if (!ignore_history || !no_update) {
 687                 struct stat stb;
 688
 689                 fd = open(hist_name, O_RDWR|O_CREAT|O_NOFOLLOW, 0600);
 690                 if (fd < 0) {
 691                         perror("ifstat: open history file");
 692                         exit(-1);
 693                 }
 694                 if ((hist_fp = fdopen(fd, "r+")) == NULL) {
 695                         perror("ifstat: fdopen history file");
 696                         exit(-1);
 697                 }
 698                 if (flock(fileno(hist_fp), LOCK_EX)) {
 699                         perror("ifstat: flock history file");
 700                         exit(-1);
 701                 }
 702                 if (fstat(fileno(hist_fp), &stb) != 0) {
 703                         perror("ifstat: fstat history file");
 704                         exit(-1);
 705                 }
 706                 if (stb.st_nlink != 1 || stb.st_uid != getuid()) {
 707                         fprintf(stderr, "ifstat: something is so wrong with history file, that I prefer not to proceed.\n");
 708                         exit(-1);
 709                 }
 710                 if (!ignore_history) {
 711                         FILE *tfp;
 712                         long uptime;
 713                         if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
 714                                 if (fscanf(tfp, "%ld", &uptime) != 1)
 715                                         uptime = -1;
 716                                 fclose(tfp);
 717                         }
 718                         if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
 719                                 fprintf(stderr, "ifstat: history is aged out, resetting\n");
 720                                 ftruncate(fileno(hist_fp), 0);
 721                         }
 722                 }
 723
 724                 load_raw_table(hist_fp);
 725
 726                 hist_db = kern_db;
 727                 kern_db = NULL;
 728         }
 729
 730         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
 731             (connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0
 732              || (strcpy(sun.sun_path+1, "ifstat0"),
 733                  connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
 734             && verify_forging(fd) == 0) {
 735                 FILE *sfp = fdopen(fd, "r");
 736                 load_raw_table(sfp);
 737                 if (hist_db && source_mismatch) {
 738                         fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
 739                         hist_db = NULL;
 740                 }
 741                 fclose(sfp);
 742         } else {
 743                 if (fd >= 0)
 744                         close(fd);
 745                 if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
 746                         fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
 747                         hist_db = NULL;
 748                         info_source[0] = 0;
 749                 }
 750                 load_info();
 751                 if (info_source[0] == 0)
 752                         strcpy(info_source, "kernel");
 753         }
 754
 755         if (!no_output) {
 756                 if (ignore_history || hist_db == NULL)
 757                         dump_kern_db(stdout);
 758                 else
 759                         dump_incr_db(stdout);
 760         }
 761         if (!no_update) {
 762                 ftruncate(fileno(hist_fp), 0);
 763                 rewind(hist_fp);
 764                 dump_raw_db(hist_fp, 1);
 765                 fflush(hist_fp);
 766         }
 767         exit(0);
 768 }