1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="sd_is_fifo">
<refentryinfo>
<title>sd_is_fifo</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>sd_is_fifo</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_is_fifo</refname>
<refname>sd_is_socket</refname>
<refname>sd_is_socket_inet</refname>
<refname>sd_is_socket_unix</refname>
<refname>sd_is_mq</refname>
<refname>sd_is_special</refname>
<refpurpose>Check the type of a file descriptor</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_is_fifo</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_is_socket</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>family</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>int <parameter>listening</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_is_socket_inet</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>family</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>int <parameter>listening</parameter></paramdef>
<paramdef>uint16_t <parameter>port</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_is_socket_unix</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>int <parameter>type</parameter></paramdef>
<paramdef>int <parameter>listening</parameter></paramdef>
<paramdef>const char* <parameter>path</parameter></paramdef>
<paramdef>size_t <parameter>length</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_is_mq</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_is_special</function></funcdef>
<paramdef>int <parameter>fd</parameter></paramdef>
<paramdef>const char *<parameter>path</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_is_fifo()</function> may be called
to check whether the specified file descriptor refers
to a FIFO or pipe. If the <parameter>path</parameter>
parameter is not <constant>NULL</constant>, it is
checked whether the FIFO is bound to the specified
file system path.</para>
<para><function>sd_is_socket()</function> may be
called to check whether the specified file descriptor
refers to a socket. If the
<parameter>family</parameter> parameter is not
<constant>AF_UNSPEC</constant>, it is checked whether
the socket is of the specified family (AF_UNIX,
<constant>AF_INET</constant>, ...). If the
<parameter>type</parameter> parameter is not 0, it is
checked whether the socket is of the specified type
(<constant>SOCK_STREAM</constant>,
<constant>SOCK_DGRAM</constant>, ...). If the
<parameter>listening</parameter> parameter is positive,
it is checked whether the socket is in accepting mode,
i.e. <function>listen()</function> has been called for
it. If <parameter>listening</parameter> is 0, it is
checked whether the socket is not in this mode. If the
parameter is negative, no such check is made. The
<parameter>listening</parameter> parameter should only
be used for stream sockets and should be set to a
negative value otherwise.</para>
<para><function>sd_is_socket_inet()</function> is
similar to <function>sd_is_socket()</function>, but
optionally checks the IPv4 or IPv6 port number the
socket is bound to, unless <parameter>port</parameter>
is zero. For this call <parameter>family</parameter>
must be passed as either <constant>AF_UNSPEC</constant>, <constant>AF_INET</constant>, or
<constant>AF_INET6</constant>.</para>
<para><function>sd_is_socket_unix()</function> is
similar to <function>sd_is_socket()</function> but
optionally checks the <constant>AF_UNIX</constant> path the socket is bound
to, unless the <parameter>path</parameter> parameter
is <constant>NULL</constant>. For normal file system <constant>AF_UNIX</constant> sockets,
set the <parameter>length</parameter> parameter to 0. For
Linux abstract namespace sockets, set the
<parameter>length</parameter> to the size of the
address, including the initial 0 byte, and set the
<parameter>path</parameter> to the initial 0 byte of
the socket address.</para>
<para><function>sd_is_mq()</function> may be called to
check whether the specified file descriptor refers to
a POSIX message queue. If the
<parameter>path</parameter> parameter is not
<constant>NULL</constant>, it is checked whether the
message queue is bound to the specified name.</para>
<para><function>sd_is_special()</function> may be
called to check whether the specified file descriptor
refers to a special file. If the
<parameter>path</parameter> parameter is not
<constant>NULL</constant>, it is checked whether the file
descriptor is bound to the specified file
name. Special files in this context are character
device nodes and files in <filename>/proc</filename>
or <filename>/sys</filename>.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>On failure, these calls return a negative
errno-style error code. If the file descriptor is of
the specified type and bound to the specified address,
a positive return value is returned, otherwise
zero.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>These APIs are implemented as a shared library,
which can be compiled and linked to with the
<constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
<para>Internally, these function use a combination of
<filename>fstat()</filename> and
<filename>getsockname()</filename> to check the file
descriptor type and where it is bound to.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
