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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 #include <sys/cdefs.h>
     29 #include <sys/types.h>
     30 #include <endian.h>
     31 #include <netdb.h>
     32 #include "servent.h"
     33 #include "services.h"
     34 
     35 void
     36 setservent(int f)
     37 {
     38     res_static  rs = __res_get_static();
     39     if (rs) {
     40         rs->servent_ptr = NULL;
     41     }
     42 }
     43 
     44 void
     45 endservent(void)
     46 {
     47     /* nothing to do */
     48 }
     49 
     50 struct servent *
     51 getservent_r( res_static  rs )
     52 {
     53     const char*  p;
     54     const char*  q;
     55     int          namelen;
     56     int          nn,count;
     57     int          total = 0;
     58     int          port;
     59     char*        p2;
     60 
     61     p = rs->servent_ptr;
     62     if (p == NULL)
     63         p = _services;
     64     else if (p[0] == 0)
     65         return NULL;
     66 
     67     /* first compute the total size */
     68     namelen = p[0];
     69     total  += namelen + 1;
     70     q       = p + 1 + namelen + 3;  /* skip name + port + proto */
     71     count   = q[0];   /* get aliascount */
     72     q      += 1;
     73 
     74     total += (count+1)*sizeof(char*);
     75     for (nn = 0; nn < count; nn++) {
     76         int  len2 = q[0];
     77         total += 1 + len2;
     78         q     += 1 + len2;
     79     }
     80 
     81     /* reallocate the thread-specific servent struct */
     82     p2 = realloc( (char*)rs->servent.s_aliases, total );
     83     if (p2 == NULL)
     84         return NULL;
     85 
     86     /* now write to it */
     87     rs->servent.s_aliases = (char**) p2;
     88     p2                   += (count+1)*sizeof(char*);
     89     rs->servent.s_name    = p2;
     90     p2                   += namelen + 1;
     91     rs->servent.s_proto   = p2;
     92 
     93     /* copy name + port + setup protocol */
     94     memcpy( rs->servent.s_name, p+1, namelen );
     95     rs->servent.s_name[namelen] = 0;
     96     p += 1 + namelen;
     97 
     98     /* s_port must be in network byte order */
     99     port = ((((unsigned char*)p)[0] << 8) |
    100              ((unsigned char*)p)[1]);
    101 
    102     rs->servent.s_port  = htons(port);
    103     rs->servent.s_proto = p[2] == 't' ? "tcp" : "udp";
    104     p += 4;  /* skip port(2) + proto(1) + aliascount(1) */
    105 
    106     for (nn = 0; nn < count; nn++) {
    107         int  len2 = p[0];
    108         rs->servent.s_aliases[nn] = p2;
    109         memcpy( p2, p+1, len2 );
    110         p2[len2] = 0;
    111         p2 += len2 + 1;
    112         p  += len2 + 1;
    113     }
    114     rs->servent.s_aliases[nn] = NULL;
    115 
    116     rs->servent_ptr = p;
    117 
    118     return &rs->servent;
    119 }
    120 
    121 struct servent *
    122 getservent(void)
    123 {
    124     res_static   rs = __res_get_static();
    125 
    126     if (rs == NULL) return NULL;
    127 
    128     return getservent_r(rs);
    129 }
    130