crypto/external/bsd/openssh/dist/misc.c

   1 /*      $NetBSD$        */
   2 /* $OpenBSD: misc.c,v 1.71 2009/02/21 19:32:04 tobias Exp $ */
   3 /*
   4  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   5  * Copyright (c) 2005,2006 Damien Miller.  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  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29 __RCSID("$NetBSD: misc.c,v 1.23 2009/02/16 20:53:54 christos Exp $");
  30 #include <sys/types.h>
  31 #include <sys/ioctl.h>
  32 #include <sys/socket.h>
  33 #include <sys/param.h>
  34
  35 #include <net/if.h>
  36 #include <net/if_tun.h>
  37 #include <netinet/in.h>
  38 #include <netinet/tcp.h>
  39
  40 #include <errno.h>
  41 #include <fcntl.h>
  42 #include <netdb.h>
  43 #include <paths.h>
  44 #include <pwd.h>
  45 #include <stdarg.h>
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <string.h>
  49 #include <unistd.h>
  50
  51 #include "xmalloc.h"
  52 #include "misc.h"
  53 #include "log.h"
  54 #include "ssh.h"
  55
  56 /* remove newline at end of string */
  57 char *
  58 chop(char *s)
  59 {
  60         char *t = s;
  61         while (*t) {
  62                 if (*t == '\n' || *t == '\r') {
  63                         *t = '\0';
  64                         return s;
  65                 }
  66                 t++;
  67         }
  68         return s;
  69
  70 }
  71
  72 /* set/unset filedescriptor to non-blocking */
  73 int
  74 set_nonblock(int fd)
  75 {
  76         int val;
  77
  78         val = fcntl(fd, F_GETFL, 0);
  79         if (val < 0) {
  80                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
  81                 return (-1);
  82         }
  83         if (val & O_NONBLOCK) {
  84                 debug3("fd %d is O_NONBLOCK", fd);
  85                 return (0);
  86         }
  87         debug2("fd %d setting O_NONBLOCK", fd);
  88         val |= O_NONBLOCK;
  89         if (fcntl(fd, F_SETFL, val) == -1) {
  90                 debug("fcntl(%d, F_SETFL, O_NONBLOCK): %s", fd,
  91                     strerror(errno));
  92                 return (-1);
  93         }
  94         return (0);
  95 }
  96
  97 int
  98 unset_nonblock(int fd)
  99 {
 100         int val;
 101
 102         val = fcntl(fd, F_GETFL, 0);
 103         if (val < 0) {
 104                 error("fcntl(%d, F_GETFL, 0): %s", fd, strerror(errno));
 105                 return (-1);
 106         }
 107         if (!(val & O_NONBLOCK)) {
 108                 debug3("fd %d is not O_NONBLOCK", fd);
 109                 return (0);
 110         }
 111         debug("fd %d clearing O_NONBLOCK", fd);
 112         val &= ~O_NONBLOCK;
 113         if (fcntl(fd, F_SETFL, val) == -1) {
 114                 debug("fcntl(%d, F_SETFL, ~O_NONBLOCK): %s",
 115                     fd, strerror(errno));
 116                 return (-1);
 117         }
 118         return (0);
 119 }
 120
 121 const char *
 122 ssh_gai_strerror(int gaierr)
 123 {
 124         if (gaierr == EAI_SYSTEM)
 125                 return strerror(errno);
 126         return gai_strerror(gaierr);
 127 }
 128
 129 /* disable nagle on socket */
 130 void
 131 set_nodelay(int fd)
 132 {
 133         int opt;
 134         socklen_t optlen;
 135
 136         optlen = sizeof opt;
 137         if (getsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, &optlen) == -1) {
 138                 debug("getsockopt TCP_NODELAY: %.100s", strerror(errno));
 139                 return;
 140         }
 141         if (opt == 1) {
 142                 debug2("fd %d is TCP_NODELAY", fd);
 143                 return;
 144         }
 145         opt = 1;
 146         debug2("fd %d setting TCP_NODELAY", fd);
 147         if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt) == -1)
 148                 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
 149 }
 150
 151 /* Characters considered whitespace in strsep calls. */
 152 #define WHITESPACE " \t\r\n"
 153 #define QUOTE   "\""
 154
 155 /* return next token in configuration line */
 156 char *
 157 strdelim(char **s)
 158 {
 159         char *old;
 160         int wspace = 0;
 161
 162         if (*s == NULL)
 163                 return NULL;
 164
 165         old = *s;
 166
 167         *s = strpbrk(*s, WHITESPACE QUOTE "=");
 168         if (*s == NULL)
 169                 return (old);
 170
 171         if (*s[0] == '\"') {
 172                 memmove(*s, *s + 1, strlen(*s)); /* move nul too */
 173                 /* Find matching quote */
 174                 if ((*s = strpbrk(*s, QUOTE)) == NULL) {
 175                         return (NULL);          /* no matching quote */
 176                 } else {
 177                         *s[0] = '\0';
 178                         return (old);
 179                 }
 180         }
 181
 182         /* Allow only one '=' to be skipped */
 183         if (*s[0] == '=')
 184                 wspace = 1;
 185         *s[0] = '\0';
 186
 187         /* Skip any extra whitespace after first token */
 188         *s += strspn(*s + 1, WHITESPACE) + 1;
 189         if (*s[0] == '=' && !wspace)
 190                 *s += strspn(*s + 1, WHITESPACE) + 1;
 191
 192         return (old);
 193 }
 194
 195 struct passwd *
 196 pwcopy(struct passwd *pw)
 197 {
 198         struct passwd *copy = xcalloc(1, sizeof(*copy));
 199
 200         copy->pw_name = xstrdup(pw->pw_name);
 201         copy->pw_passwd = xstrdup(pw->pw_passwd);
 202         copy->pw_gecos = xstrdup(pw->pw_gecos);
 203         copy->pw_uid = pw->pw_uid;
 204         copy->pw_gid = pw->pw_gid;
 205         copy->pw_expire = pw->pw_expire;
 206         copy->pw_change = pw->pw_change;
 207         copy->pw_class = xstrdup(pw->pw_class);
 208         copy->pw_dir = xstrdup(pw->pw_dir);
 209         copy->pw_shell = xstrdup(pw->pw_shell);
 210         return copy;
 211 }
 212
 213 /*
 214  * Convert ASCII string to TCP/IP port number.
 215  * Port must be >=0 and <=65535.
 216  * Return -1 if invalid.
 217  */
 218 int
 219 a2port(const char *s)
 220 {
 221         long long port;
 222         const char *errstr;
 223
 224         port = strtonum(s, 0, 65535, &errstr);
 225         if (errstr != NULL)
 226                 return -1;
 227         return (int)port;
 228 }
 229
 230 int
 231 a2tun(const char *s, int *remote)
 232 {
 233         const char *errstr = NULL;
 234         char *sp, *ep;
 235         int tun;
 236
 237         if (remote != NULL) {
 238                 *remote = SSH_TUNID_ANY;
 239                 sp = xstrdup(s);
 240                 if ((ep = strchr(sp, ':')) == NULL) {
 241                         xfree(sp);
 242                         return (a2tun(s, NULL));
 243                 }
 244                 ep[0] = '\0'; ep++;
 245                 *remote = a2tun(ep, NULL);
 246                 tun = a2tun(sp, NULL);
 247                 xfree(sp);
 248                 return (*remote == SSH_TUNID_ERR ? *remote : tun);
 249         }
 250
 251         if (strcasecmp(s, "any") == 0)
 252                 return (SSH_TUNID_ANY);
 253
 254         tun = strtonum(s, 0, SSH_TUNID_MAX, &errstr);
 255         if (errstr != NULL)
 256                 return (SSH_TUNID_ERR);
 257
 258         return (tun);
 259 }
 260
 261 #define SECONDS         1
 262 #define MINUTES         (SECONDS * 60)
 263 #define HOURS           (MINUTES * 60)
 264 #define DAYS            (HOURS * 24)
 265 #define WEEKS           (DAYS * 7)
 266
 267 /*
 268  * Convert a time string into seconds; format is
 269  * a sequence of:
 270  *      time[qualifier]
 271  *
 272  * Valid time qualifiers are:
 273  *      <none>  seconds
 274  *      s|S     seconds
 275  *      m|M     minutes
 276  *      h|H     hours
 277  *      d|D     days
 278  *      w|W     weeks
 279  *
 280  * Examples:
 281  *      90m     90 minutes
 282  *      1h30m   90 minutes
 283  *      2d      2 days
 284  *      1w      1 week
 285  *
 286  * Return -1 if time string is invalid.
 287  */
 288 long
 289 convtime(const char *s)
 290 {
 291         long total, secs;
 292         const char *p;
 293         char *endp;
 294
 295         errno = 0;
 296         total = 0;
 297         p = s;
 298
 299         if (p == NULL || *p == '\0')
 300                 return -1;
 301
 302         while (*p) {
 303                 secs = strtol(p, &endp, 10);
 304                 if (p == endp ||
 305                     (errno == ERANGE && (secs == LONG_MIN || secs == LONG_MAX)) ||
 306                     secs < 0)
 307                         return -1;
 308
 309                 switch (*endp++) {
 310                 case '\0':
 311                         endp--;
 312                         break;
 313                 case 's':
 314                 case 'S':
 315                         break;
 316                 case 'm':
 317                 case 'M':
 318                         secs *= MINUTES;
 319                         break;
 320                 case 'h':
 321                 case 'H':
 322                         secs *= HOURS;
 323                         break;
 324                 case 'd':
 325                 case 'D':
 326                         secs *= DAYS;
 327                         break;
 328                 case 'w':
 329                 case 'W':
 330                         secs *= WEEKS;
 331                         break;
 332                 default:
 333                         return -1;
 334                 }
 335                 total += secs;
 336                 if (total < 0)
 337                         return -1;
 338                 p = endp;
 339         }
 340
 341         return total;
 342 }
 343
 344 /*
 345  * Returns a standardized host+port identifier string.
 346  * Caller must free returned string.
 347  */
 348 char *
 349 put_host_port(const char *host, u_short port)
 350 {
 351         char *hoststr;
 352
 353         if (port == 0 || port == SSH_DEFAULT_PORT)
 354                 return(xstrdup(host));
 355         if (asprintf(&hoststr, "[%s]:%d", host, (int)port) < 0)
 356                 fatal("put_host_port: asprintf: %s", strerror(errno));
 357         debug3("put_host_port: %s", hoststr);
 358         return hoststr;
 359 }
 360
 361 /*
 362  * Search for next delimiter between hostnames/addresses and ports.
 363  * Argument may be modified (for termination).
 364  * Returns *cp if parsing succeeds.
 365  * *cp is set to the start of the next delimiter, if one was found.
 366  * If this is the last field, *cp is set to NULL.
 367  */
 368 char *
 369 hpdelim(char **cp)
 370 {
 371         char *s, *old;
 372
 373         if (cp == NULL || *cp == NULL)
 374                 return NULL;
 375
 376         old = s = *cp;
 377         if (*s == '[') {
 378                 if ((s = strchr(s, ']')) == NULL)
 379                         return NULL;
 380                 else
 381                         s++;
 382         } else if ((s = strpbrk(s, ":/")) == NULL)
 383                 s = *cp + strlen(*cp); /* skip to end (see first case below) */
 384
 385         switch (*s) {
 386         case '\0':
 387                 *cp = NULL;     /* no more fields*/
 388                 break;
 389
 390         case ':':
 391         case '/':
 392                 *s = '\0';      /* terminate */
 393                 *cp = s + 1;
 394                 break;
 395
 396         default:
 397                 return NULL;
 398         }
 399
 400         return old;
 401 }
 402
 403 char *
 404 cleanhostname(char *host)
 405 {
 406         if (*host == '[' && host[strlen(host) - 1] == ']') {
 407                 host[strlen(host) - 1] = '\0';
 408                 return (host + 1);
 409         } else
 410                 return host;
 411 }
 412
 413 char *
 414 colon(char *cp)
 415 {
 416         int flag = 0;
 417
 418         if (*cp == ':')         /* Leading colon is part of file name. */
 419                 return (0);
 420         if (*cp == '[')
 421                 flag = 1;
 422
 423         for (; *cp; ++cp) {
 424                 if (*cp == '@' && *(cp+1) == '[')
 425                         flag = 1;
 426                 if (*cp == ']' && *(cp+1) == ':' && flag)
 427                         return (cp+1);
 428                 if (*cp == ':' && !flag)
 429                         return (cp);
 430                 if (*cp == '/')
 431                         return (0);
 432         }
 433         return (0);
 434 }
 435
 436 /* function to assist building execv() arguments */
 437 void
 438 addargs(arglist *args, char *fmt, ...)
 439 {
 440         va_list ap;
 441         char *cp;
 442         u_int nalloc;
 443         int r;
 444
 445         va_start(ap, fmt);
 446         r = vasprintf(&cp, fmt, ap);
 447         va_end(ap);
 448         if (r == -1)
 449                 fatal("addargs: argument too long");
 450
 451         nalloc = args->nalloc;
 452         if (args->list == NULL) {
 453                 nalloc = 32;
 454                 args->num = 0;
 455         } else if (args->num+2 >= nalloc)
 456                 nalloc *= 2;
 457
 458         args->list = xrealloc(args->list, nalloc, sizeof(char *));
 459         args->nalloc = nalloc;
 460         args->list[args->num++] = cp;
 461         args->list[args->num] = NULL;
 462 }
 463
 464 void
 465 replacearg(arglist *args, u_int which, char *fmt, ...)
 466 {
 467         va_list ap;
 468         char *cp;
 469         int r;
 470
 471         va_start(ap, fmt);
 472         r = vasprintf(&cp, fmt, ap);
 473         va_end(ap);
 474         if (r == -1)
 475                 fatal("replacearg: argument too long");
 476
 477         if (which >= args->num)
 478                 fatal("replacearg: tried to replace invalid arg %d >= %d",
 479                     which, args->num);
 480         xfree(args->list[which]);
 481         args->list[which] = cp;
 482 }
 483
 484 void
 485 freeargs(arglist *args)
 486 {
 487         u_int i;
 488
 489         if (args->list != NULL) {
 490                 for (i = 0; i < args->num; i++)
 491                         xfree(args->list[i]);
 492                 xfree(args->list);
 493                 args->nalloc = args->num = 0;
 494                 args->list = NULL;
 495         }
 496 }
 497
 498 /*
 499  * Expands tildes in the file name.  Returns data allocated by xmalloc.
 500  * Warning: this calls getpw*.
 501  */
 502 char *
 503 tilde_expand_filename(const char *filename, uid_t uid)
 504 {
 505         const char *path, *homedir;
 506         char user[128], ret[MAXPATHLEN];
 507         struct passwd *pw;
 508         u_int len, slash;
 509
 510         if (*filename != '~')
 511                 return (xstrdup(filename));
 512         filename++;
 513
 514         path = strchr(filename, '/');
 515         if (path != NULL && path > filename) {          /* ~user/path */
 516                 slash = path - filename;
 517                 if (slash > sizeof(user) - 1)
 518                         fatal("tilde_expand_filename: ~username too long");
 519                 memcpy(user, filename, slash);
 520                 user[slash] = '\0';
 521                 if ((pw = getpwnam(user)) == NULL)
 522                         fatal("tilde_expand_filename: No such user %s", user);
 523                 homedir = pw->pw_dir;
 524         } else {
 525                 if ((pw = getpwuid(uid)) == NULL)       /* ~/path */
 526                         fatal("tilde_expand_filename: No such uid %ld",
 527                             (long)uid);
 528                 homedir = pw->pw_dir;
 529         }
 530
 531         if (strlcpy(ret, homedir, sizeof(ret)) >= sizeof(ret))
 532                 fatal("tilde_expand_filename: Path too long");
 533
 534         /* Make sure directory has a trailing '/' */
 535         len = strlen(homedir);
 536         if ((len == 0 || homedir[len - 1] != '/') &&
 537             strlcat(ret, "/", sizeof(ret)) >= sizeof(ret))
 538                 fatal("tilde_expand_filename: Path too long");
 539
 540         /* Skip leading '/' from specified path */
 541         if (path != NULL)
 542                 filename = path + 1;
 543         if (strlcat(ret, filename, sizeof(ret)) >= sizeof(ret))
 544                 fatal("tilde_expand_filename: Path too long");
 545
 546         return (xstrdup(ret));
 547 }
 548
 549 /*
 550  * Expand a string with a set of %[char] escapes. A number of escapes may be
 551  * specified as (char *escape_chars, char *replacement) pairs. The list must
 552  * be terminated by a NULL escape_char. Returns replaced string in memory
 553  * allocated by xmalloc.
 554  */
 555 char *
 556 percent_expand(const char *string, ...)
 557 {
 558 #define EXPAND_MAX_KEYS 16
 559         struct {
 560                 const char *key;
 561                 const char *repl;
 562         } keys[EXPAND_MAX_KEYS];
 563         u_int num_keys, i, j;
 564         char buf[4096];
 565         va_list ap;
 566
 567         /* Gather keys */
 568         va_start(ap, string);
 569         for (num_keys = 0; num_keys < EXPAND_MAX_KEYS; num_keys++) {
 570                 keys[num_keys].key = va_arg(ap, char *);
 571                 if (keys[num_keys].key == NULL)
 572                         break;
 573                 keys[num_keys].repl = va_arg(ap, char *);
 574                 if (keys[num_keys].repl == NULL)
 575                         fatal("percent_expand: NULL replacement");
 576         }
 577         va_end(ap);
 578
 579         if (num_keys >= EXPAND_MAX_KEYS)
 580                 fatal("percent_expand: too many keys");
 581
 582         /* Expand string */
 583         *buf = '\0';
 584         for (i = 0; *string != '\0'; string++) {
 585                 if (*string != '%') {
 586  append:
 587                         buf[i++] = *string;
 588                         if (i >= sizeof(buf))
 589                                 fatal("percent_expand: string too long");
 590                         buf[i] = '\0';
 591                         continue;
 592                 }
 593                 string++;
 594                 if (*string == '%')
 595                         goto append;
 596                 for (j = 0; j < num_keys; j++) {
 597                         if (strchr(keys[j].key, *string) != NULL) {
 598                                 i = strlcat(buf, keys[j].repl, sizeof(buf));
 599                                 if (i >= sizeof(buf))
 600                                         fatal("percent_expand: string too long");
 601                                 break;
 602                         }
 603                 }
 604                 if (j >= num_keys)
 605                         fatal("percent_expand: unknown key %%%c", *string);
 606         }
 607         return (xstrdup(buf));
 608 #undef EXPAND_MAX_KEYS
 609 }
 610
 611 /*
 612  * Read an entire line from a public key file into a static buffer, discarding
 613  * lines that exceed the buffer size.  Returns 0 on success, -1 on failure.
 614  */
 615 int
 616 read_keyfile_line(FILE *f, const char *filename, char *buf, size_t bufsz,
 617    u_long *lineno)
 618 {
 619         while (fgets(buf, bufsz, f) != NULL) {
 620                 if (buf[0] == '\0')
 621                         continue;
 622                 (*lineno)++;
 623                 if (buf[strlen(buf) - 1] == '\n' || feof(f)) {
 624                         return 0;
 625                 } else {
 626                         debug("%s: %s line %lu exceeds size limit", __func__,
 627                             filename, *lineno);
 628                         /* discard remainder of line */
 629                         while (fgetc(f) != '\n' && !feof(f))
 630                                 ;       /* nothing */
 631                 }
 632         }
 633         return -1;
 634 }
 635
 636 int
 637 tun_open(int tun, int mode)
 638 {
 639         struct ifreq ifr;
 640         int fd = -1, sock, flag;
 641         const char *tunbase = mode == SSH_TUNMODE_ETHERNET ? "tap" : "tun";
 642
 643         /* Open the tunnel device */
 644         if (tun <= SSH_TUNID_MAX) {
 645                 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name),
 646                     "/dev/%s%d", tunbase, tun);
 647                 fd = open(ifr.ifr_name, O_RDWR);
 648         } else if (tun == SSH_TUNID_ANY) {
 649                 for (tun = 100; tun >= 0; tun--) {
 650                         snprintf(ifr.ifr_name, sizeof(ifr.ifr_name),
 651                             "/dev/%s%d", tunbase, tun);
 652                         if ((fd = open(ifr.ifr_name, O_RDWR)) >= 0)
 653                                 break;
 654                 }
 655         } else {
 656                 debug("%s: invalid tunnel %u", __func__, tun);
 657                 return (-1);
 658         }
 659
 660         if (fd < 0) {
 661                 debug("%s: %s open failed: %s", __func__, ifr.ifr_name,
 662                     strerror(errno));
 663                 return (-1);
 664         }
 665
 666
 667         /* Turn on tunnel headers */
 668         flag = 1;
 669         if (mode != SSH_TUNMODE_ETHERNET &&
 670             ioctl(fd, TUNSIFHEAD, &flag) == -1) {
 671                 debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
 672                     strerror(errno));
 673                 close(fd);
 674                 return -1;
 675         }
 676
 677         debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
 678         /* Set the tunnel device operation mode */
 679         if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
 680                 goto failed;
 681
 682         if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
 683                 goto failed;
 684
 685 #if 0
 686         /* Set interface mode */
 687         ifr.ifr_flags &= ~IFF_UP;
 688         if (mode == SSH_TUNMODE_ETHERNET)
 689                 ifr.ifr_flags |= IFF_LINK0;
 690         else
 691                 ifr.ifr_flags &= ~IFF_LINK0;
 692         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 693                 goto failed;
 694 #endif
 695
 696         /* Bring interface up */
 697         ifr.ifr_flags |= IFF_UP;
 698         if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
 699                 goto failed;
 700
 701         close(sock);
 702         return (fd);
 703
 704  failed:
 705         if (fd >= 0)
 706                 close(fd);
 707         if (sock >= 0)
 708                 close(sock);
 709         debug("%s: failed to set %s mode %d: %s", __func__, ifr.ifr_name,
 710             mode, strerror(errno));
 711         return (-1);
 712 }
 713
 714 void
 715 sanitise_stdfd(void)
 716 {
 717         int nullfd, dupfd;
 718
 719         if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 720                 fprintf(stderr, "Couldn't open /dev/null: %s\n",
 721                     strerror(errno));
 722                 exit(1);
 723         }
 724         while (++dupfd <= 2) {
 725                 /* Only clobber closed fds */
 726                 if (fcntl(dupfd, F_GETFL, 0) >= 0)
 727                         continue;
 728                 if (dup2(nullfd, dupfd) == -1) {
 729                         fprintf(stderr, "dup2: %s\n", strerror(errno));
 730                         exit(1);
 731                 }
 732         }
 733         if (nullfd > 2)
 734                 close(nullfd);
 735 }
 736
 737 char *
 738 tohex(const void *vp, size_t l)
 739 {
 740         const u_char *p = (const u_char *)vp;
 741         char b[3], *r;
 742         size_t i, hl;
 743
 744         if (l > 65536)
 745                 return xstrdup("tohex: length > 65536");
 746
 747         hl = l * 2 + 1;
 748         r = xcalloc(1, hl);
 749         for (i = 0; i < l; i++) {
 750                 snprintf(b, sizeof(b), "%02x", p[i]);
 751                 strlcat(r, b, hl);
 752         }
 753         return (r);
 754 }
 755
 756 u_int64_t
 757 get_u64(const void *vp)
 758 {
 759         const u_char *p = (const u_char *)vp;
 760         u_int64_t v;
 761
 762         v  = (u_int64_t)p[0] << 56;
 763         v |= (u_int64_t)p[1] << 48;
 764         v |= (u_int64_t)p[2] << 40;
 765         v |= (u_int64_t)p[3] << 32;
 766         v |= (u_int64_t)p[4] << 24;
 767         v |= (u_int64_t)p[5] << 16;
 768         v |= (u_int64_t)p[6] << 8;
 769         v |= (u_int64_t)p[7];
 770
 771         return (v);
 772 }
 773
 774 u_int32_t
 775 get_u32(const void *vp)
 776 {
 777         const u_char *p = (const u_char *)vp;
 778         u_int32_t v;
 779
 780         v  = (u_int32_t)p[0] << 24;
 781         v |= (u_int32_t)p[1] << 16;
 782         v |= (u_int32_t)p[2] << 8;
 783         v |= (u_int32_t)p[3];
 784
 785         return (v);
 786 }
 787
 788 u_int16_t
 789 get_u16(const void *vp)
 790 {
 791         const u_char *p = (const u_char *)vp;
 792         u_int16_t v;
 793
 794         v  = (u_int16_t)p[0] << 8;
 795         v |= (u_int16_t)p[1];
 796
 797         return (v);
 798 }
 799
 800 void
 801 put_u64(void *vp, u_int64_t v)
 802 {
 803         u_char *p = (u_char *)vp;
 804
 805         p[0] = (u_char)(v >> 56) & 0xff;
 806         p[1] = (u_char)(v >> 48) & 0xff;
 807         p[2] = (u_char)(v >> 40) & 0xff;
 808         p[3] = (u_char)(v >> 32) & 0xff;
 809         p[4] = (u_char)(v >> 24) & 0xff;
 810         p[5] = (u_char)(v >> 16) & 0xff;
 811         p[6] = (u_char)(v >> 8) & 0xff;
 812         p[7] = (u_char)v & 0xff;
 813 }
 814
 815 void
 816 put_u32(void *vp, u_int32_t v)
 817 {
 818         u_char *p = (u_char *)vp;
 819
 820         p[0] = (u_char)(v >> 24) & 0xff;
 821         p[1] = (u_char)(v >> 16) & 0xff;
 822         p[2] = (u_char)(v >> 8) & 0xff;
 823         p[3] = (u_char)v & 0xff;
 824 }
 825
 826
 827 void
 828 put_u16(void *vp, u_int16_t v)
 829 {
 830         u_char *p = (u_char *)vp;
 831
 832         p[0] = (u_char)(v >> 8) & 0xff;
 833         p[1] = (u_char)v & 0xff;
 834 }
 835
 836 void
 837 ms_subtract_diff(struct timeval *start, int *ms)
 838 {
 839         struct timeval diff, finish;
 840
 841         gettimeofday(&finish, NULL);
 842         timersub(&finish, start, &diff);
 843         *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
 844 }
 845
 846 void
 847 ms_to_timeval(struct timeval *tv, int ms)
 848 {
 849         if (ms < 0)
 850                 ms = 0;
 851         tv->tv_sec = ms / 1000;
 852         tv->tv_usec = (ms % 1000) * 1000;
 853 }
 854