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.\" $FreeBSD: src/lib/libc/net/getservent.3,v 1.7.2.5 2001/12/14 18:33:55 ru Exp $ 34.\" $DragonFly: src/lib/libc/net/getservent.3,v 1.2 2003/06/17 04:26:44 dillon Exp $ 35.\" 36.Dd July 9, 1995 37.Dt GETSERVENT 3 38.Os 39.Sh NAME 40.Nm getservent , 41.Nm getservbyport , 42.Nm getservbyname , 43.Nm setservent , 44.Nm endservent 45.Nd get service entry 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.In netdb.h 50.Ft struct servent * 51.Fn getservent 52.Ft struct servent * 53.Fn getservbyname "const char *name" "const char *proto" 54.Ft struct servent * 55.Fn getservbyport "int port" "const char *proto" 56.Ft void 57.Fn setservent "int stayopen" 58.Ft void 59.Fn endservent void 60.Sh DESCRIPTION 61The 62.Fn getservent , 63.Fn getservbyname , 64and 65.Fn getservbyport 66functions 67each return a pointer to an object with the 68following structure 69containing the broken-out 70fields of a line in the network services data base, 71.Pa /etc/services . 72.Bd -literal -offset indent 73struct servent { 74 char *s_name; /* official name of service */ 75 char **s_aliases; /* alias list */ 76 int s_port; /* port service resides at */ 77 char *s_proto; /* protocol to use */ 78}; 79.Ed 80.Pp 81The members of this structure are: 82.Bl -tag -width s_aliases 83.It Fa s_name 84The official name of the service. 85.It Fa s_aliases 86A zero terminated list of alternate names for the service. 87.It Fa s_port 88The port number at which the service resides. 89Port numbers are returned in network byte order. 90.It Fa s_proto 91The name of the protocol to use when contacting the 92service. 93.El 94.Pp 95The 96.Fn getservent 97function 98reads the next line of the file, opening the file if necessary. 99.Pp 100The 101.Fn setservent 102function 103opens and rewinds the file. If the 104.Fa stayopen 105flag is non-zero, 106the net data base will not be closed after each call to 107.Fn getservbyname 108or 109.Fn getservbyport . 110.Pp 111The 112.Fn endservent 113function 114closes the file. 115.Pp 116The 117.Fn getservbyname 118and 119.Fn getservbyport 120functions 121sequentially search from the beginning 122of the file until a matching 123protocol name or 124port number (which must be specified in 125network byte order) is found, 126or until 127.Dv EOF 128is encountered. 129If a protocol name is also supplied (non- 130.Dv NULL ) , 131searches must also match the protocol. 132.Sh FILES 133.Bl -tag -width /etc/services -compact 134.It Pa /etc/services 135.El 136.Sh DIAGNOSTICS 137Null pointer 138(0) returned on 139.Dv EOF 140or error. 141.Sh SEE ALSO 142.Xr getprotoent 3 , 143.Xr services 5 144.Sh HISTORY 145The 146.Fn getservent , 147.Fn getservbyport , 148.Fn getservbyname , 149.Fn setservent , 150and 151.Fn endservent 152functions appeared in 153.Bx 4.2 . 154.Sh BUGS 155These functions use static data storage; 156if the data is needed for future use, it should be 157copied before any subsequent calls overwrite it. 158Expecting port numbers to fit in a 32 bit 159quantity is probably naive. 160