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/netdevice.h>
  33
  34 #include <SNAPSHOT.h>
  35
  36 int dump_zeros = 0;
  37 int reset_history = 0;
  38 int ignore_history = 0;
  39 int no_output = 0;
  40 int no_update = 0;
  41 int scan_interval = 0;
  42 int time_constant = 0;
  43 int show_errors = 0;
  44 double W;
  45 char **patterns;
  46 int npatterns;
  47
  48 char info_source[128];
  49 int source_mismatch;
  50
  51 #define MAXS (sizeof(struct net_device_stats)/sizeof(unsigned long))
  52
  53 struct ifstat_ent
  54 {
  55         struct ifstat_ent       *next;
  56         char                    *name;
  57         int                     ifindex;
  58         unsigned long long      val[MAXS];
  59         double                  rate[MAXS];
  60         unsigned long           ival[MAXS];
  61 };
  62
  63 struct ifstat_ent *kern_db;
  64 struct ifstat_ent *hist_db;
  65
  66 static int match(const char *id)
  67 {
  68         int i;
  69
  70         if (npatterns == 0)
  71                 return 1;
  72
  73         for (i=0; i<npatterns; i++) {
  74                 if (!fnmatch(patterns[i], id, 0))
  75                         return 1;
  76         }
  77         return 0;
  78 }
  79
  80 static int get_nlmsg(const struct sockaddr_nl *who,
  81                      struct nlmsghdr *m, void *arg)
  82 {
  83         struct ifinfomsg *ifi = NLMSG_DATA(m);
  84         struct rtattr * tb[IFLA_MAX+1];
  85         int len = m->nlmsg_len;
  86         struct ifstat_ent *n;
  87         int i;
  88
  89         if (m->nlmsg_type != RTM_NEWLINK)
  90                 return 0;
  91
  92         len -= NLMSG_LENGTH(sizeof(*ifi));
  93         if (len < 0)
  94                 return -1;
  95
  96         if (!(ifi->ifi_flags&IFF_UP))
  97                 return 0;
  98
  99         parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
 100         if (tb[IFLA_IFNAME] == NULL || tb[IFLA_STATS] == NULL)
 101                 return 0;
 102
 103         n = malloc(sizeof(*n));
 104         if (!n)
 105                 abort();
 106         n->ifindex = ifi->ifi_index;
 107         n->name = strdup(RTA_DATA(tb[IFLA_IFNAME]));
 108         memcpy(&n->ival, RTA_DATA(tb[IFLA_STATS]), sizeof(n->ival));
 109         memset(&n->rate, 0, sizeof(n->rate));
 110         for (i=0; i<MAXS; i++)
 111                 n->val[i] = n->ival[i];
 112         n->next = kern_db;
 113         kern_db = n;
 114         return 0;
 115 }
 116
 117 void load_info(void)
 118 {
 119         struct ifstat_ent *db, *n;
 120         struct rtnl_handle rth;
 121
 122         if (rtnl_open(&rth, 0) < 0)
 123                 exit(1);
 124
 125         if (rtnl_wilddump_request(&rth, AF_INET, RTM_GETLINK) < 0) {
 126                 perror("Cannot send dump request");
 127                 exit(1);
 128         }
 129
 130         if (rtnl_dump_filter(&rth, get_nlmsg, NULL, NULL, NULL) < 0) {
 131                 fprintf(stderr, "Dump terminated\n");
 132                 exit(1);
 133         }
 134
 135         rtnl_close(&rth);
 136
 137         db = kern_db;
 138         kern_db = NULL;
 139
 140         while (db) {
 141                 n = db;
 142                 db = db->next;
 143                 n->next = kern_db;
 144                 kern_db = n;
 145         }
 146 }
 147
 148 void load_raw_table(FILE *fp)
 149 {
 150         char buf[4096];
 151         struct ifstat_ent *db = NULL;
 152         struct ifstat_ent *n;
 153
 154         while (fgets(buf, sizeof(buf), fp) != NULL) {
 155                 char *p;
 156                 char *next;
 157                 int i;
 158
 159                 if (buf[0] == '#') {
 160                         buf[strlen(buf)-1] = 0;
 161                         if (info_source[0] && strcmp(info_source, buf+1))
 162                                 source_mismatch = 1;
 163                         strncpy(info_source, buf+1, sizeof(info_source)-1);
 164                         continue;
 165                 }
 166                 if ((n = malloc(sizeof(*n))) == NULL)
 167                         abort();
 168
 169                 if (!(p = strchr(buf, ' ')))
 170                         abort();
 171                 *p++ = 0;
 172
 173                 if (sscanf(buf, "%d", &n->ifindex) != 1)
 174                         abort();
 175                 if (!(next = strchr(p, ' ')))
 176                         abort();
 177                 *next++ = 0;
 178
 179                 n->name = strdup(p);
 180                 p = next;
 181
 182                 for (i=0; i<MAXS; i++) {
 183                         unsigned rate;
 184                         if (!(next = strchr(p, ' ')))
 185                                 abort();
 186                         *next++ = 0;
 187                         if (sscanf(p, "%llu", n->val+i) != 1)
 188                                 abort();
 189                         n->ival[i] = (unsigned long)n->val[i];
 190                         p = next;
 191                         if (!(next = strchr(p, ' ')))
 192                                 abort();
 193                         *next++ = 0;
 194                         if (sscanf(p, "%u", &rate) != 1)
 195                                 abort();
 196                         n->rate[i] = rate;
 197                         p = next;
 198                 }
 199                 n->next = db;
 200                 db = n;
 201         }
 202
 203         while (db) {
 204                 n = db;
 205                 db = db->next;
 206                 n->next = kern_db;
 207                 kern_db = n;
 208         }
 209 }
 210
 211 void dump_raw_db(FILE *fp, int to_hist)
 212 {
 213         struct ifstat_ent *n, *h;
 214         h = hist_db;
 215         fprintf(fp, "#%s\n", info_source);
 216
 217         for (n=kern_db; n; n=n->next) {
 218                 int i;
 219                 unsigned long long *vals = n->val;
 220                 double *rates = n->rate;
 221                 if (!match(n->name)) {
 222                         struct ifstat_ent *h1;
 223                         if (!to_hist)
 224                                 continue;
 225                         for (h1 = h; h1; h1 = h1->next) {
 226                                 if (h1->ifindex == n->ifindex) {
 227                                         vals = h1->val;
 228                                         rates = h1->rate;
 229                                         h = h1->next;
 230                                         break;
 231                                 }
 232                         }
 233                 }
 234                 fprintf(fp, "%d %s ", n->ifindex, n->name);
 235                 for (i=0; i<MAXS; i++)
 236                         fprintf(fp, "%llu %u ", vals[i], (unsigned)rates[i]);
 237                 fprintf(fp, "\n");
 238         }
 239 }
 240
 241 /* use communication definitions of meg/kilo etc */
 242 static const unsigned long long giga = 1000000000ull;
 243 static const unsigned long long mega = 1000000;
 244 static const unsigned long long kilo = 1000;
 245
 246 void format_rate(FILE *fp, unsigned long long *vals, double *rates, int i)
 247 {
 248         char temp[64];
 249         if (vals[i] > giga)
 250                 fprintf(fp, "%7lluM ", vals[i]/mega);
 251         else if (vals[i] > mega)
 252                 fprintf(fp, "%7lluK ", vals[i]/kilo);
 253         else
 254                 fprintf(fp, "%8llu ", vals[i]);
 255
 256         if (rates[i] > mega) {
 257                 sprintf(temp, "%uM", (unsigned)(rates[i]/mega));
 258                 fprintf(fp, "%-6s ", temp);
 259         } else if (rates[i] > kilo) {
 260                 sprintf(temp, "%uK", (unsigned)(rates[i]/kilo));
 261                 fprintf(fp, "%-6s ", temp);
 262         } else
 263                 fprintf(fp, "%-6u ", (unsigned)rates[i]);
 264 }
 265
 266 void format_pair(FILE *fp, unsigned long long *vals, int i, int k)
 267 {
 268         char temp[64];
 269         if (vals[i] > giga)
 270                 fprintf(fp, "%7lluM ", vals[i]/mega);
 271         else if (vals[i] > mega)
 272                 fprintf(fp, "%7lluK ", vals[i]/kilo);
 273         else
 274                 fprintf(fp, "%8llu ", vals[i]);
 275
 276         if (vals[k] > giga) {
 277                 sprintf(temp, "%uM", (unsigned)(vals[k]/mega));
 278                 fprintf(fp, "%-6s ", temp);
 279         } else if (vals[k] > mega) {
 280                 sprintf(temp, "%uK", (unsigned)(vals[k]/kilo));
 281                 fprintf(fp, "%-6s ", temp);
 282         } else
 283                 fprintf(fp, "%-6u ", (unsigned)vals[k]);
 284 }
 285
 286 void print_head(FILE *fp)
 287 {
 288         fprintf(fp, "#%s\n", info_source);
 289         fprintf(fp, "%-15s ", "Interface");
 290
 291         fprintf(fp, "%8s/%-6s ", "RX Pkts", "Rate");
 292         fprintf(fp, "%8s/%-6s ", "TX Pkts", "Rate");
 293         fprintf(fp, "%8s/%-6s ", "RX Data", "Rate");
 294         fprintf(fp, "%8s/%-6s\n","TX Data", "Rate");
 295
 296         if (!show_errors) {
 297                 fprintf(fp, "%-15s ", "");
 298                 fprintf(fp, "%8s/%-6s ", "RX Errs", "Drop");
 299                 fprintf(fp, "%8s/%-6s ", "TX Errs", "Drop");
 300                 fprintf(fp, "%8s/%-6s ", "RX Over", "Rate");
 301                 fprintf(fp, "%8s/%-6s\n","TX Coll", "Rate");
 302         } else {
 303                 fprintf(fp, "%-15s ", "");
 304                 fprintf(fp, "%8s/%-6s ", "RX Errs", "Rate");
 305                 fprintf(fp, "%8s/%-6s ", "RX Drop", "Rate");
 306                 fprintf(fp, "%8s/%-6s ", "RX Over", "Rate");
 307                 fprintf(fp, "%8s/%-6s\n","RX Leng", "Rate");
 308
 309                 fprintf(fp, "%-15s ", "");
 310                 fprintf(fp, "%8s/%-6s ", "RX Crc", "Rate");
 311                 fprintf(fp, "%8s/%-6s ", "RX Frm", "Rate");
 312                 fprintf(fp, "%8s/%-6s ", "RX Fifo", "Rate");
 313                 fprintf(fp, "%8s/%-6s\n","RX Miss", "Rate");
 314
 315                 fprintf(fp, "%-15s ", "");
 316                 fprintf(fp, "%8s/%-6s ", "TX Errs", "Rate");
 317                 fprintf(fp, "%8s/%-6s ", "TX Drop", "Rate");
 318                 fprintf(fp, "%8s/%-6s ", "TX Coll", "Rate");
 319                 fprintf(fp, "%8s/%-6s\n","TX Carr", "Rate");
 320
 321                 fprintf(fp, "%-15s ", "");
 322                 fprintf(fp, "%8s/%-6s ", "TX Abrt", "Rate");
 323                 fprintf(fp, "%8s/%-6s ", "TX Fifo", "Rate");
 324                 fprintf(fp, "%8s/%-6s ", "TX Hear", "Rate");
 325                 fprintf(fp, "%8s/%-6s\n","TX Wind", "Rate");
 326         }
 327 }
 328
 329 void print_one_if(FILE *fp, struct ifstat_ent *n, unsigned long long *vals)
 330 {
 331         int i;
 332         fprintf(fp, "%-15s ", n->name);
 333         for (i=0; i<4; i++)
 334                 format_rate(fp, vals, n->rate, i);
 335         fprintf(fp, "\n");
 336
 337         if (!show_errors) {
 338                 fprintf(fp, "%-15s ", "");
 339                 format_pair(fp, vals, 4, 6);
 340                 format_pair(fp, vals, 5, 7);
 341                 format_rate(fp, vals, n->rate, 11);
 342                 format_rate(fp, vals, n->rate, 9);
 343                 fprintf(fp, "\n");
 344         } else {
 345                 fprintf(fp, "%-15s ", "");
 346                 format_rate(fp, vals, n->rate, 4);
 347                 format_rate(fp, vals, n->rate, 6);
 348                 format_rate(fp, vals, n->rate, 11);
 349                 format_rate(fp, vals, n->rate, 10);
 350                 fprintf(fp, "\n");
 351
 352                 fprintf(fp, "%-15s ", "");
 353                 format_rate(fp, vals, n->rate, 12);
 354                 format_rate(fp, vals, n->rate, 13);
 355                 format_rate(fp, vals, n->rate, 14);
 356                 format_rate(fp, vals, n->rate, 15);
 357                 fprintf(fp, "\n");
 358
 359                 fprintf(fp, "%-15s ", "");
 360                 format_rate(fp, vals, n->rate, 5);
 361                 format_rate(fp, vals, n->rate, 7);
 362                 format_rate(fp, vals, n->rate, 9);
 363                 format_rate(fp, vals, n->rate, 17);
 364                 fprintf(fp, "\n");
 365
 366                 fprintf(fp, "%-15s ", "");
 367                 format_rate(fp, vals, n->rate, 16);
 368                 format_rate(fp, vals, n->rate, 18);
 369                 format_rate(fp, vals, n->rate, 19);
 370                 format_rate(fp, vals, n->rate, 20);
 371                 fprintf(fp, "\n");
 372         }
 373 }
 374
 375
 376 void dump_kern_db(FILE *fp)
 377 {
 378         struct ifstat_ent *n, *h;
 379         h = hist_db;
 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
 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
 422 void sigchild(int signo)
 423 {
 424 }
 425
 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
 485 void server_loop(int fd)
 486 {
 487         struct timeval snaptime;
 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                 gettimeofday(&now, NULL);
 502                 tdiff = T_DIFF(now, snaptime);
 503                 if (tdiff >= scan_interval) {
 504                         update_db(tdiff);
 505                         snaptime = now;
 506                         tdiff = 0;
 507                 }
 508                 if (poll(&p, 1, tdiff + scan_interval) > 0
 509                     && (p.revents&POLLIN)) {
 510                         int clnt = accept(fd, NULL, NULL);
 511                         if (clnt >= 0) {
 512                                 pid_t pid;
 513                                 if (children >= 5) {
 514                                         close(clnt);
 515                                 } else if ((pid = fork()) != 0) {
 516                                         if (pid>0)
 517                                                 children++;
 518                                         close(clnt);
 519                                 } else {
 520                                         FILE *fp = fdopen(clnt, "w");
 521                                         if (fp) {
 522                                                 if (tdiff > 0)
 523                                                         update_db(tdiff);
 524                                                 dump_raw_db(fp, 0);
 525                                         }
 526                                         exit(0);
 527                                 }
 528                         }
 529                 }
 530                 while (children && waitpid(-1, &status, WNOHANG) > 0)
 531                         children--;
 532         }
 533 }
 534
 535 int verify_forging(int fd)
 536 {
 537         struct ucred cred;
 538         int olen = sizeof(cred);
 539         if (getsockopt(fd, SOL_SOCKET, SO_PEERCRED, (void*)&cred, &olen) ||
 540             olen < sizeof(cred))
 541                 return -1;
 542         if (cred.uid == getuid() || cred.uid == 0)
 543                 return 0;
 544         return -1;
 545 }
 546
 547 static void usage(void) __attribute__((noreturn));
 548
 549 static void usage(void)
 550 {
 551         fprintf(stderr,
 552 "Usage: ifstat [OPTION] [ PATTERN [ PATTERN ] ]\n"
 553 "   -h, --help          this message\n"
 554 "   -a, --ignore        ignore history\n"
 555 "   -d, --scan=SECS     sample every statistics every SECS\n"
 556 "   -e, --errors        show errors\n"
 557 "   -n, --nooutput      do history only\n"
 558 "   -r, --reset         reset history\n"
 559 "   -s, --noupdate      don;t update history\n"
 560 "   -t, --interval=SECS report average over the last SECS\n"
 561 "   -V, --version       output version information\n"
 562 "   -z, --zeros         show entries with zero activity\n"
 563 "   -e, --errors        show errors\n"
 564 "   -z, --zeros         show entries with zero activity\n");
 565
 566         exit(-1);
 567 }
 568
 569 static const struct option longopts[] = {
 570         { "help", 0, 0, 'h' },
 571         { "ignore",  0,  0, 'a' },
 572         { "scan", 1, 0, 'd'},
 573         { "errors", 0, 0, 'e' },
 574         { "nooutput", 0, 0, 'n' },
 575         { "reset", 0, 0, 'r' },
 576         { "noupdate", 0, 0, 's' },
 577         { "interval", 1, 0, 't' },
 578         { "version", 0, 0, 'V' },
 579         { "zeros", 0, 0, 'z' },
 580         { "errors", 0, 0, 'e' },
 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 (fork())
 664                         exit(0);
 665                 chdir("/");
 666                 close(0); close(1); close(2); setsid();
 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), getenv("IFSTAT_HISTORY"));
 678         else
 679                 sprintf(hist_name, "%s/.ifstat.u%d", P_tmpdir, getuid());
 680
 681         if (reset_history)
 682                 unlink(hist_name);
 683
 684         if (!ignore_history || !no_update) {
 685                 struct stat stb;
 686
 687                 fd = open(hist_name, O_RDWR|O_CREAT|O_NOFOLLOW, 0600);
 688                 if (fd < 0) {
 689                         perror("ifstat: open history file");
 690                         exit(-1);
 691                 }
 692                 if ((hist_fp = fdopen(fd, "r+")) == NULL) {
 693                         perror("ifstat: fdopen history file");
 694                         exit(-1);
 695                 }
 696                 if (flock(fileno(hist_fp), LOCK_EX)) {
 697                         perror("ifstat: flock history file");
 698                         exit(-1);
 699                 }
 700                 if (fstat(fileno(hist_fp), &stb) != 0) {
 701                         perror("ifstat: fstat history file");
 702                         exit(-1);
 703                 }
 704                 if (stb.st_nlink != 1 || stb.st_uid != getuid()) {
 705                         fprintf(stderr, "ifstat: something is so wrong with history file, that I prefer not to proceed.\n");
 706                         exit(-1);
 707                 }
 708                 if (!ignore_history) {
 709                         FILE *tfp;
 710                         long uptime;
 711                         if ((tfp = fopen("/proc/uptime", "r")) != NULL) {
 712                                 if (fscanf(tfp, "%ld", &uptime) != 1)
 713                                         uptime = -1;
 714                                 fclose(tfp);
 715                         }
 716                         if (uptime >= 0 && time(NULL) >= stb.st_mtime+uptime) {
 717                                 fprintf(stderr, "ifstat: history is aged out, resetting\n");
 718                                 ftruncate(fileno(hist_fp), 0);
 719                         }
 720                 }
 721
 722                 load_raw_table(hist_fp);
 723
 724                 hist_db = kern_db;
 725                 kern_db = NULL;
 726         }
 727
 728         if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) >= 0 &&
 729             (connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0
 730              || (strcpy(sun.sun_path+1, "ifstat0"),
 731                  connect(fd, (struct sockaddr*)&sun, 2+1+strlen(sun.sun_path+1)) == 0))
 732             && verify_forging(fd) == 0) {
 733                 FILE *sfp = fdopen(fd, "r");
 734                 load_raw_table(sfp);
 735                 if (hist_db && source_mismatch) {
 736                         fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
 737                         hist_db = NULL;
 738                 }
 739                 fclose(sfp);
 740         } else {
 741                 if (fd >= 0)
 742                         close(fd);
 743                 if (hist_db && info_source[0] && strcmp(info_source, "kernel")) {
 744                         fprintf(stderr, "ifstat: history is stale, ignoring it.\n");
 745                         hist_db = NULL;
 746                         info_source[0] = 0;
 747                 }
 748                 load_info();
 749                 if (info_source[0] == 0)
 750                         strcpy(info_source, "kernel");
 751         }
 752
 753         if (!no_output) {
 754                 if (ignore_history || hist_db == NULL)
 755                         dump_kern_db(stdout);
 756                 else
 757                         dump_incr_db(stdout);
 758         }
 759         if (!no_update) {
 760                 ftruncate(fileno(hist_fp), 0);
 761                 rewind(hist_fp);
 762                 dump_raw_db(hist_fp, 1);
 763                 fflush(hist_fp);
 764         }
 765         exit(0);
 766 }