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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 <malloc.h>
     32 #include <netdb.h>
     33 #include "servent.h"
     34 #include "services.h"
     35 
     36 void
     37 setservent(int f)
     38 {
     39     res_static  rs = __res_get_static();
     40     if (rs) {
     41         rs->servent_ptr = NULL;
     42     }
     43 }
     44 
     45 void
     46 endservent(void)
     47 {
     48     /* nothing to do */
     49 }
     50 
     51 struct servent *
     52 getservent_r( res_static  rs )
     53 {
     54     const char*  p;
     55     const char*  q;
     56     int          namelen;
     57     int          nn,count;
     58     int          total = 0;
     59     int          port;
     60     char*        p2;
     61 
     62     p = rs->servent_ptr;
     63     if (p == NULL)
     64         p = _services;
     65     else if (p[0] == 0)
     66         return NULL;
     67 
     68     /* first compute the total size */
     69     namelen = p[0];
     70     total  += namelen + 1;
     71     q       = p + 1 + namelen + 3;  /* skip name + port + proto */
     72     count   = q[0];   /* get aliascount */
     73     q      += 1;
     74 
     75     total += (count+1)*sizeof(char*);
     76     for (nn = 0; nn < count; nn++) {
     77         int  len2 = q[0];
     78         total += 1 + len2;
     79         q     += 1 + len2;
     80     }
     81 
     82     /* reallocate the thread-specific servent struct */
     83     p2 = realloc( (char*)rs->servent.s_aliases, total );
     84     if (p2 == NULL)
     85         return NULL;
     86 
     87     /* now write to it */
     88     rs->servent.s_aliases = (char**) p2;
     89     p2                   += (count+1)*sizeof(char*);
     90     rs->servent.s_name    = p2;
     91     p2                   += namelen + 1;
     92     rs->servent.s_proto   = p2;
     93 
     94     /* copy name + port + setup protocol */
     95     memcpy( rs->servent.s_name, p+1, namelen );
     96     rs->servent.s_name[namelen] = 0;
     97     p += 1 + namelen;
     98 
     99     /* s_port must be in network byte order */
    100     port = ((((unsigned char*)p)[0] << 8) |
    101              ((unsigned char*)p)[1]);
    102 
    103     rs->servent.s_port  = htons(port);
    104     rs->servent.s_proto = p[2] == 't' ? "tcp" : "udp";
    105     p += 4;  /* skip port(2) + proto(1) + aliascount(1) */
    106 
    107     for (nn = 0; nn < count; nn++) {
    108         int  len2 = p[0];
    109         rs->servent.s_aliases[nn] = p2;
    110         memcpy( p2, p+1, len2 );
    111         p2[len2] = 0;
    112         p2 += len2 + 1;
    113         p  += len2 + 1;
    114     }
    115     rs->servent.s_aliases[nn] = NULL;
    116 
    117     rs->servent_ptr = p;
    118 
    119     return &rs->servent;
    120 }
    121 
    122 struct servent *
    123 getservent(void)
    124 {
    125     res_static   rs = __res_get_static();
    126 
    127     if (rs == NULL) return NULL;
    128 
    129     return getservent_r(rs);
    130 }
    131