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
setservent(int f)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
endservent(void)46 endservent(void)
47 {
48     /* nothing to do */
49 }
50 
51 struct servent *
getservent_r(res_static rs)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 *
getservent(void)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