bindresvport.c

   1 /*
   2  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   3  * unrestricted use provided that this legend is included on all tape
   4  * media and as a part of the software program in whole or part.  Users
   5  * may copy or modify Sun RPC without charge, but are not authorized
   6  * to license or distribute it to anyone else except as part of a product or
   7  * program developed by the user.
   8  *
   9  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  10  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  11  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  12  *
  13  * Sun RPC is provided with no support and without any obligation on the
  14  * part of Sun Microsystems, Inc. to assist in its use, correction,
  15  * modification or enhancement.
  16  *
  17  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  18  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  19  * OR ANY PART THEREOF.
  20  *
  21  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  22  * or profits or other special, indirect and consequential damages, even if
  23  * Sun has been advised of the possibility of such damages.
  24  *
  25  * Sun Microsystems, Inc.
  26  * 2550 Garcia Avenue
  27  * Mountain View, California  94043
  28  */
  29 /*
  30  * Copyright (c) 1987 by Sun Microsystems, Inc.
  31  */
  32
  33 #define __FORCE_GLIBC
  34 #include <features.h>
  35
  36 #include <errno.h>
  37 #include <unistd.h>
  38 #include <string.h>
  39 #include <sys/types.h>
  40 #include <sys/socket.h>
  41 #include <netinet/in.h>
  42
  43
  44 /*
  45  * Bind a socket to a privileged IP port
  46  */
  47 int
  48 bindresvport (int sd, struct sockaddr_in *sin)
  49 {
  50   int res;
  51   static short port;
  52   struct sockaddr_in myaddr;
  53   int i;
  54
  55 #define STARTPORT 600
  56 #define ENDPORT (IPPORT_RESERVED - 1)
  57 #define NPORTS  (ENDPORT - STARTPORT + 1)
  58
  59   if (sin == (struct sockaddr_in *) 0)
  60     {
  61       sin = &myaddr;
  62       memset (sin, 0, sizeof (*sin));
  63       sin->sin_family = AF_INET;
  64     }
  65   else if (sin->sin_family != AF_INET)
  66     {
  67       __set_errno (EPFNOSUPPORT);
  68       return -1;
  69     }
  70
  71   if (port == 0)
  72     {
  73       port = (getpid () % NPORTS) + STARTPORT;
  74     }
  75   res = -1;
  76   __set_errno (EADDRINUSE);
  77
  78   for (i = 0; i < NPORTS && res < 0 && errno == EADDRINUSE; ++i)
  79     {
  80       sin->sin_port = htons (port);
  81       if (++port > ENDPORT)
  82         {
  83           port = STARTPORT;
  84         }
  85       res = bind(sd, (struct sockaddr *)sin, sizeof(struct sockaddr_in));
  86     }
  87
  88   return res;
  89 }
  90 libc_hidden_def(bindresvport)