[apple/libc.git] / net / getservent.3

.\" Copyright (c) 1983, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\"     From: @(#)getservent.3	8.3 (Berkeley) 1/12/94
.\" $FreeBSD: src/lib/libc/net/getservent.3,v 1.12 2001/10/01 16:08:55 ru Exp $
.\"
.Dd July 9, 1995
.Dt GETSERVENT 3
.Os
.Sh NAME
.Nm getservent ,
.Nm getservbyport ,
.Nm getservbyname ,
.Nm setservent ,
.Nm endservent
.Nd get service entry
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In netdb.h
.Ft struct servent *
.Fn getservent
.Ft struct servent *
.Fn getservbyname "const char *name" "const char *proto"
.Ft struct servent *
.Fn getservbyport "int port" "const char *proto"
.Ft void
.Fn setservent "int stayopen"
.Ft void
.Fn endservent void
.Sh DESCRIPTION
The
.Fn getservent ,
.Fn getservbyname ,
and
.Fn getservbyport
functions
each return a pointer to an object with the
following structure
containing the broken-out
fields of a line in the network services data base,
.Pa /etc/services .
.Bd -literal -offset indent
struct	servent {
	char	*s_name;	/* official name of service */
	char	**s_aliases;	/* alias list */
	int	s_port;		/* port service resides at */
	char	*s_proto;	/* protocol to use */
};
.Ed
.Pp
The members of this structure are:
.Bl -tag -width s_aliases
.It Fa s_name
The official name of the service.
.It Fa s_aliases
A zero terminated list of alternate names for the service.
.It Fa s_port
The port number at which the service resides.
Port numbers are returned in network byte order.
.It Fa s_proto
The name of the protocol to use when contacting the
service.
.El
.Pp
The
.Fn getservent
function
reads the next line of the file, opening the file if necessary.
.Pp
The
.Fn setservent
function
opens and rewinds the file.  If the
.Fa stayopen
flag is non-zero,
the net data base will not be closed after each call to
.Fn getservbyname
or
.Fn getservbyport .
.Pp
The
.Fn endservent
function
closes the file.
.Pp
The
.Fn getservbyname
and
.Fn getservbyport
functions
sequentially search from the beginning
of the file until a matching
protocol name or
port number (which must be specified in
network byte order) is found,
or until
.Dv EOF
is encountered.
If a protocol name is also supplied (non-
.Dv NULL ) ,
searches must also match the protocol.
.Sh FILES
.Bl -tag -width /etc/services -compact
.It Pa /etc/services
.El
.Sh DIAGNOSTICS
Null pointer
(0) returned on
.Dv EOF
or error.
.Sh SEE ALSO
.Xr getprotoent 3 ,
.Xr services 5
.Sh HISTORY
The
.Fn getservent ,
.Fn getservbyport ,
.Fn getservbyname ,
.Fn setservent ,
and
.Fn endservent
functions appeared in
.Bx 4.2 .
.Sh BUGS
These functions use static data storage;
if the data is needed for future use, it should be
copied before any subsequent calls overwrite it.
Expecting port numbers to fit in a 32 bit
quantity is probably naive.
Commit	Line	Data
5b2abdfb A	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 1.12 2001/10/01 16:08:55 ru Exp $
	34	.\"
	35	.Dd July 9, 1995
	36	.Dt GETSERVENT 3
	37	.Os
	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 LIBRARY
	46	.Lb libc
	47	.Sh SYNOPSIS
	48	.In netdb.h
	49	.Ft struct servent *
	50	.Fn getservent
	51	.Ft struct servent *
	52	.Fn getservbyname "const char name" "const char proto"
	53	.Ft struct servent *
	54	.Fn getservbyport "int port" "const char *proto"
	55	.Ft void
	56	.Fn setservent "int stayopen"
	57	.Ft void
	58	.Fn endservent void
	59	.Sh DESCRIPTION
	60	The
	61	.Fn getservent ,
	62	.Fn getservbyname ,
	63	and
	64	.Fn getservbyport
65	functions
66	each return a pointer to an object with the
67	following structure
68	containing the broken-out
69	fields of a line in the network services data base,
70	.Pa /etc/services .
71	.Bd -literal -offset indent
72	struct servent {
73	char s_name; / official name of service */
74	char *s_aliases; / alias list */
75	int s_port; /* port service resides at */
76	char s_proto; / protocol to use */
77	};
78	.Ed
79	.Pp
80	The members of this structure are:
81	.Bl -tag -width s_aliases
82	.It Fa s_name
83	The official name of the service.
84	.It Fa s_aliases
85	A zero terminated list of alternate names for the service.
86	.It Fa s_port
87	The port number at which the service resides.
88	Port numbers are returned in network byte order.
89	.It Fa s_proto
90	The name of the protocol to use when contacting the
91	service.
92	.El
93	.Pp
94	The
95	.Fn getservent
96	function
97	reads the next line of the file, opening the file if necessary.
98	.Pp
99	The
100	.Fn setservent
101	function
102	opens and rewinds the file. If the
103	.Fa stayopen
104	flag is non-zero,
105	the net data base will not be closed after each call to
106	.Fn getservbyname
107	or
108	.Fn getservbyport .
109	.Pp
110	The
111	.Fn endservent
112	function
113	closes the file.
114	.Pp
115	The
116	.Fn getservbyname
117	and
118	.Fn getservbyport
119	functions
120	sequentially search from the beginning
121	of the file until a matching
122	protocol name or
123	port number (which must be specified in
124	network byte order) is found,
125	or until
126	.Dv EOF
127	is encountered.
128	If a protocol name is also supplied (non-
129	.Dv NULL ) ,
130	searches must also match the protocol.
131	.Sh FILES
132	.Bl -tag -width /etc/services -compact
133	.It Pa /etc/services
134	.El
135	.Sh DIAGNOSTICS
136	Null pointer
137	(0) returned on
138	.Dv EOF
139	or error.
140	.Sh SEE ALSO
141	.Xr getprotoent 3 ,
142	.Xr services 5
143	.Sh HISTORY
144	The
145	.Fn getservent ,
146	.Fn getservbyport ,
147	.Fn getservbyname ,
148	.Fn setservent ,
149	and
150	.Fn endservent
151	functions appeared in
152	.Bx 4.2 .
153	.Sh BUGS
154	These functions use static data storage;
155	if the data is needed for future use, it should be
156	copied before any subsequent calls overwrite it.
157	Expecting port numbers to fit in a 32 bit
158	quantity is probably naive.