4.3BSD - /usr/src/lib/libc/net/res_init.c

   1: /*
   2:  * Copyright (c) 1985 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #if defined(LIBC_SCCS) && !defined(lint)
   8: static char sccsid[] = "@(#)res_init.c	6.5 (Berkeley) 4/11/86";
   9: #endif LIBC_SCCS and not lint
  10: 
  11: #include <sys/types.h>
  12: #include <sys/socket.h>
  13: #include <netinet/in.h>
  14: #include <stdio.h>
  15: #include <arpa/nameser.h>
  16: #include <resolv.h>
  17: 
  18: /*
  19:  * Resolver configuration file. Contains the address of the
  20:  * inital name server to query and the default domain for
  21:  * non fully qualified domain names.
  22:  */
  23: 
  24: #ifdef CONFFILE
  25: char    *conffile = CONFFILE;
  26: #else
  27: char    *conffile = "/etc/resolv.conf";
  28: #endif
  29: 
  30: /*
  31:  * Resolver state default settings
  32:  */
  33: 
  34: #ifndef RES_TIMEOUT
  35: #define RES_TIMEOUT 4
  36: #endif
  37: 
  38: struct state _res = {
  39:     RES_TIMEOUT,                 /* retransmition time interval */
  40:     4,                           /* number of times to retransmit */
  41:     RES_RECURSE|RES_DEFNAMES,    /* options flags */
  42:     1,                           /* number of name servers */
  43: };
  44: 
  45: /*
  46:  * Set up default settings.  If the configuration file exist, the values
  47:  * there will have precedence.  Otherwise, the server address is set to
  48:  * INADDR_ANY and the default domain name comes from the gethostname().
  49:  *
  50:  * The configuration file should only be used if you want to redefine your
  51:  * domain or run without a server on your machine.
  52:  *
  53:  * Return 0 if completes successfully, -1 on error
  54:  */
  55: res_init()
  56: {
  57:     register FILE *fp;
  58:     char buf[BUFSIZ], *cp;
  59:     extern u_long inet_addr();
  60:     extern char *index();
  61:     extern char *strcpy(), *strncpy();
  62: #ifdef DEBUG
  63:     extern char *getenv();
  64: #endif DEBUG
  65:     int n = 0;    /* number of nameserver records read from file */
  66: 
  67:     _res.nsaddr.sin_addr.s_addr = INADDR_ANY;
  68:     _res.nsaddr.sin_family = AF_INET;
  69:     _res.nsaddr.sin_port = htons(NAMESERVER_PORT);
  70:     _res.nscount = 1;
  71:     _res.defdname[0] = '\0';
  72: 
  73:     if ((fp = fopen(conffile, "r")) != NULL) {
  74:         /* read the config file */
  75:         while (fgets(buf, sizeof(buf), fp) != NULL) {
  76:             /* read default domain name */
  77:             if (!strncmp(buf, "domain", sizeof("domain") - 1)) {
  78:                 cp = buf + sizeof("domain") - 1;
  79:                 while (*cp == ' ' || *cp == '\t')
  80:                     cp++;
  81:                 if (*cp == '\0')
  82:                     continue;
  83:                 (void)strncpy(_res.defdname, cp, sizeof(_res.defdname));
  84:                 _res.defdname[sizeof(_res.defdname) - 1] = '\0';
  85:                 if ((cp = index(_res.defdname, '\n')) != NULL)
  86:                     *cp = '\0';
  87:                 continue;
  88:             }
  89:             /* read nameservers to query */
  90:             if (!strncmp(buf, "nameserver",
  91:                sizeof("nameserver") - 1) && (n < MAXNS)) {
  92:                 cp = buf + sizeof("nameserver") - 1;
  93:                 while (*cp == ' ' || *cp == '\t')
  94:                     cp++;
  95:                 if (*cp == '\0')
  96:                     continue;
  97:                 _res.nsaddr_list[n].sin_addr.s_addr = inet_addr(cp);
  98:                 if (_res.nsaddr_list[n].sin_addr.s_addr == (unsigned)-1)
  99:                     _res.nsaddr_list[n].sin_addr.s_addr = INADDR_ANY;
 100:                 _res.nsaddr_list[n].sin_family = AF_INET;
 101:                 _res.nsaddr_list[n].sin_port = htons(NAMESERVER_PORT);
 102:                 if ( ++n >= MAXNS) {
 103:                     n = MAXNS;
 104: #ifdef DEBUG
 105:                     if ( _res.options & RES_DEBUG )
 106:                         printf("MAXNS reached, reading resolv.conf\n");
 107: #endif DEBUG
 108:                 }
 109:                 continue;
 110:             }
 111:         }
 112:         if ( n > 1 )
 113:             _res.nscount = n;
 114:         (void) fclose(fp);
 115:     }
 116:     if (_res.defdname[0] == 0) {
 117:         if (gethostname(buf, sizeof(_res.defdname)) == 0 &&
 118:            (cp = index(buf, '.')))
 119:              (void)strcpy(_res.defdname, cp + 1);
 120:     }
 121: 
 122: #ifdef DEBUG
 123:     /* Allow user to override the local domain definition */
 124:     if ((cp = getenv("LOCALDOMAIN")) != NULL)
 125:         (void)strncpy(_res.defdname, cp, sizeof(_res.defdname));
 126: #endif DEBUG
 127:     _res.options |= RES_INIT;
 128:     return(0);
 129: }

Defined functions

Defined variables

Defined macros