1/*
2 * Copyright (c) 2010, Oracle America, Inc.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are
6 * met:
7 *
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
11 * copyright notice, this list of conditions and the following
12 * disclaimer in the documentation and/or other materials
13 * provided with the distribution.
14 * * Neither the name of the "Oracle America, Inc." nor the names of its
15 * contributors may be used to endorse or promote products derived
16 * from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
23 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
25 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
27 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <errno.h>
33#include <unistd.h>
34#include <string.h>
35#include <sys/types.h>
36#include <sys/socket.h>
37#include <netinet/in.h>
38#include <libc-lock.h>
39
40/*
41 * Locks the static variables in this file.
42 */
43__libc_lock_define_initialized (static, lock);
44
45/*
46 * Bind a socket to a privileged IP port
47 */
48int
49bindresvport (int sd, struct sockaddr_in *sin)
50{
51 static short port;
52 struct sockaddr_in myaddr;
53 int i;
54
55#define STARTPORT 600
56#define LOWPORT 512
57#define ENDPORT (IPPORT_RESERVED - 1)
58#define NPORTS (ENDPORT - STARTPORT + 1)
59 static short startport = STARTPORT;
60
61 if (sin == (struct sockaddr_in *) 0)
62 {
63 sin = &myaddr;
64 memset (sin, 0, sizeof (*sin));
65 sin->sin_family = AF_INET;
66 }
67 else if (sin->sin_family != AF_INET)
68 {
69 __set_errno (EAFNOSUPPORT);
70 return -1;
71 }
72
73 if (port == 0)
74 {
75 port = (__getpid () % NPORTS) + STARTPORT;
76 }
77
78 /* Initialize to make gcc happy. */
79 int res = -1;
80
81 int nports = ENDPORT - startport + 1;
82 int endport = ENDPORT;
83
84 __libc_lock_lock (lock);
85
86 again:
87 for (i = 0; i < nports; ++i)
88 {
89 sin->sin_port = htons (port++);
90 if (port > endport)
91 port = startport;
92 res = __bind (sd, sin, sizeof (struct sockaddr_in));
93 if (res >= 0 || errno != EADDRINUSE)
94 break;
95 }
96
97 if (i == nports && startport != LOWPORT)
98 {
99 startport = LOWPORT;
100 endport = STARTPORT - 1;
101 nports = STARTPORT - LOWPORT;
102 port = LOWPORT + port % (STARTPORT - LOWPORT);
103 goto again;
104 }
105
106 __libc_lock_unlock (lock);
107
108 return res;
109}
110libc_hidden_def (bindresvport)
111