lib/roken/mini_inetd.c

   1 /*
   2  * Copyright (c) 1995 - 2001 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35
  36 #include <err.h>
  37 #include "roken.h"
  38
  39 /*
  40  * accept a connection on `s' and pretend it's served by inetd.
  41  */
  42
  43 static void
  44 accept_it (int s)
  45 {
  46     int s2;
  47
  48     s2 = accept(s, NULL, NULL);
  49     if(s2 < 0)
  50         err (1, "accept");
  51     close(s);
  52     dup2(s2, STDIN_FILENO);
  53     dup2(s2, STDOUT_FILENO);
  54     /* dup2(s2, STDERR_FILENO); */
  55     close(s2);
  56 }
  57
  58 /*
  59  * Listen on a specified port, emulating inetd.
  60  */
  61
  62 void ROKEN_LIB_FUNCTION
  63 mini_inetd_addrinfo (struct addrinfo *ai)
  64 {
  65     int ret;
  66     struct addrinfo *a;
  67     int n, nalloc, i;
  68     int *fds;
  69     fd_set orig_read_set, read_set;
  70     int max_fd = -1;
  71
  72     for (nalloc = 0, a = ai; a != NULL; a = a->ai_next)
  73         ++nalloc;
  74
  75     fds = malloc (nalloc * sizeof(*fds));
  76     if (fds == NULL)
  77         errx (1, "mini_inetd: out of memory");
  78
  79     FD_ZERO(&orig_read_set);
  80
  81     for (i = 0, a = ai; a != NULL; a = a->ai_next) {
  82         fds[i] = socket (a->ai_family, a->ai_socktype, a->ai_protocol);
  83         if (fds[i] < 0)
  84             continue;
  85         socket_set_reuseaddr (fds[i], 1);
  86         socket_set_ipv6only(fds[i], 1);
  87         if (bind (fds[i], a->ai_addr, a->ai_addrlen) < 0) {
  88             warn ("bind af = %d", a->ai_family);
  89             close(fds[i]);
  90             continue;
  91         }
  92         if (listen (fds[i], SOMAXCONN) < 0) {
  93             warn ("listen af = %d", a->ai_family);
  94             close(fds[i]);
  95             continue;
  96         }
  97         if (fds[i] >= FD_SETSIZE)
  98             errx (1, "fd too large");
  99         FD_SET(fds[i], &orig_read_set);
 100         max_fd = max(max_fd, fds[i]);
 101         ++i;
 102     }
 103     if (i == 0)
 104         errx (1, "no sockets");
 105     n = i;
 106
 107     do {
 108         read_set = orig_read_set;
 109
 110         ret = select (max_fd + 1, &read_set, NULL, NULL, NULL);
 111         if (ret < 0 && errno != EINTR)
 112             err (1, "select");
 113     } while (ret <= 0);
 114
 115     for (i = 0; i < n; ++i)
 116         if (FD_ISSET (fds[i], &read_set)) {
 117             accept_it (fds[i]);
 118             for (i = 0; i < n; ++i)
 119               close(fds[i]);
 120             free(fds);
 121             return;
 122         }
 123     abort ();
 124 }
 125
 126 void ROKEN_LIB_FUNCTION
 127 mini_inetd (int port)
 128 {
 129     int error;
 130     struct addrinfo *ai, hints;
 131     char portstr[NI_MAXSERV];
 132
 133     memset (&hints, 0, sizeof(hints));
 134     hints.ai_flags    = AI_PASSIVE;
 135     hints.ai_socktype = SOCK_STREAM;
 136     hints.ai_family   = PF_UNSPEC;
 137
 138     snprintf (portstr, sizeof(portstr), "%d", ntohs(port));
 139
 140     error = getaddrinfo (NULL, portstr, &hints, &ai);
 141     if (error)
 142         errx (1, "getaddrinfo: %s", gai_strerror (error));
 143
 144     mini_inetd_addrinfo(ai);
 145
 146     freeaddrinfo(ai);
 147 }