1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" From: @(#)getservent.3 8.3 (Berkeley) 1/12/94 33.\" $Id$ 34.\" 35.Dd July 9, 1995 36.Dt GETSERVENT 3 37.Os BSD 4.2 38.Sh NAME 39.Nm getservent , 40.Nm getservbyport , 41.Nm getservbyname , 42.Nm setservent , 43.Nm endservent 44.Nd get service entry 45.Sh SYNOPSIS 46.Fd #include <netdb.h> 47.Ft struct servent * 48.Fn getservent 49.Ft struct servent * 50.Fn getservbyname "const char *name" "const char *proto" 51.Ft struct servent * 52.Fn getservbyport "int port" "const char *proto" 53.Ft void 54.Fn setservent "int stayopen" 55.Ft void 56.Fn endservent void 57.Sh DESCRIPTION 58The 59.Fn getservent , 60.Fn getservbyname , 61and 62.Fn getservbyport 63functions 64each return a pointer to an object with the 65following structure 66containing the broken-out 67fields of a line in the network services data base, 68.Pa /etc/services . 69.Bd -literal -offset indent 70struct servent { 71 char *s_name; /* official name of service */ 72 char **s_aliases; /* alias list */ 73 int s_port; /* port service resides at */ 74 char *s_proto; /* protocol to use */ 75}; 76.Ed 77.Pp 78The members of this structure are: 79.Bl -tag -width s_aliases 80.It Fa s_name 81The official name of the service. 82.It Fa s_aliases 83A zero terminated list of alternate names for the service. 84.It Fa s_port 85The port number at which the service resides. 86Port numbers are returned in network byte order. 87.It Fa s_proto 88The name of the protocol to use when contacting the 89service. 90.El 91.Pp 92The 93.Fn getservent 94function 95reads the next line of the file, opening the file if necessary. 96.Pp 97The 98.Fn setservent 99function 100opens and rewinds the file. If the 101.Fa stayopen 102flag is non-zero, 103the net data base will not be closed after each call to 104.Fn getservbyname 105or 106.Fn getservbyport . 107.Pp 108The 109.Fn endservent 110function 111closes the file. 112.Pp 113The 114.Fn getservbyname 115and 116.Fn getservbyport 117functions 118sequentially search from the beginning 119of the file until a matching 120protocol name or 121port number is found, 122or until 123.Dv EOF 124is encountered. 125If a protocol name is also supplied (non- 126.Dv NULL ) , 127searches must also match the protocol. 128.ne 1i 129.Sh FILES 130.Bl -tag -width /etc/services -compact 131.It Pa /etc/services 132.El 133.Sh DIAGNOSTICS 134Null pointer 135(0) returned on 136.Dv EOF 137or error. 138.Sh SEE ALSO 139.Xr getprotoent 3 , 140.Xr services 5 141.Sh HISTORY 142The 143.Fn getservent , 144.Fn getservbyport , 145.Fn getservbyname , 146.Fn setservent , 147and 148.Fn endservent 149functions appeared in 150.Bx 4.2 . 151.Sh BUGS 152These functions use static data storage; 153if the data is needed for future use, it should be 154copied before any subsequent calls overwrite it. 155Expecting port numbers to fit in a 32 bit 156quantity is probably naive. 157