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f9378423 | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
f9378423 | 5 | |
6a70f3aa | 6 | <refentry id="sd_is_fifo" |
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7 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
8 | ||
9 | <refentryinfo> | |
10 | <title>sd_is_fifo</title> | |
11 | <productname>systemd</productname> | |
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12 | </refentryinfo> |
13 | ||
14 | <refmeta> | |
15 | <refentrytitle>sd_is_fifo</refentrytitle> | |
16 | <manvolnum>3</manvolnum> | |
17 | </refmeta> | |
18 | ||
19 | <refnamediv> | |
20 | <refname>sd_is_fifo</refname> | |
21 | <refname>sd_is_socket</refname> | |
22 | <refname>sd_is_socket_inet</refname> | |
23 | <refname>sd_is_socket_unix</refname> | |
f6f372d2 | 24 | <refname>sd_is_socket_sockaddr</refname> |
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25 | <refname>sd_is_mq</refname> |
26 | <refname>sd_is_special</refname> | |
27 | <refpurpose>Check the type of a file descriptor</refpurpose> | |
28 | </refnamediv> | |
29 | ||
30 | <refsynopsisdiv> | |
31 | <funcsynopsis> | |
32 | <funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo> | |
33 | ||
34 | <funcprototype> | |
35 | <funcdef>int <function>sd_is_fifo</function></funcdef> | |
36 | <paramdef>int <parameter>fd</parameter></paramdef> | |
37 | <paramdef>const char *<parameter>path</parameter></paramdef> | |
38 | </funcprototype> | |
39 | ||
40 | <funcprototype> | |
41 | <funcdef>int <function>sd_is_socket</function></funcdef> | |
42 | <paramdef>int <parameter>fd</parameter></paramdef> | |
43 | <paramdef>int <parameter>family</parameter></paramdef> | |
44 | <paramdef>int <parameter>type</parameter></paramdef> | |
45 | <paramdef>int <parameter>listening</parameter></paramdef> | |
46 | </funcprototype> | |
47 | ||
48 | <funcprototype> | |
49 | <funcdef>int <function>sd_is_socket_inet</function></funcdef> | |
50 | <paramdef>int <parameter>fd</parameter></paramdef> | |
51 | <paramdef>int <parameter>family</parameter></paramdef> | |
52 | <paramdef>int <parameter>type</parameter></paramdef> | |
53 | <paramdef>int <parameter>listening</parameter></paramdef> | |
54 | <paramdef>uint16_t <parameter>port</parameter></paramdef> | |
55 | </funcprototype> | |
56 | ||
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57 | <funcprototype> |
58 | <funcdef>int <function>sd_is_socket_sockaddr</function></funcdef> | |
59 | <paramdef>int <parameter>fd</parameter></paramdef> | |
60 | <paramdef>int <parameter>type</parameter></paramdef> | |
61 | <paramdef>const struct sockaddr *<parameter>addr</parameter></paramdef> | |
62 | <paramdef>unsigned <parameter>addr_len</parameter></paramdef> | |
63 | <paramdef>int <parameter>listening</parameter></paramdef> | |
64 | </funcprototype> | |
65 | ||
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66 | <funcprototype> |
67 | <funcdef>int <function>sd_is_socket_unix</function></funcdef> | |
68 | <paramdef>int <parameter>fd</parameter></paramdef> | |
69 | <paramdef>int <parameter>type</parameter></paramdef> | |
70 | <paramdef>int <parameter>listening</parameter></paramdef> | |
71 | <paramdef>const char *<parameter>path</parameter></paramdef> | |
72 | <paramdef>size_t <parameter>length</parameter></paramdef> | |
73 | </funcprototype> | |
74 | ||
75 | <funcprototype> | |
76 | <funcdef>int <function>sd_is_mq</function></funcdef> | |
77 | <paramdef>int <parameter>fd</parameter></paramdef> | |
78 | <paramdef>const char *<parameter>path</parameter></paramdef> | |
79 | </funcprototype> | |
80 | ||
81 | <funcprototype> | |
82 | <funcdef>int <function>sd_is_special</function></funcdef> | |
83 | <paramdef>int <parameter>fd</parameter></paramdef> | |
84 | <paramdef>const char *<parameter>path</parameter></paramdef> | |
85 | </funcprototype> | |
86 | ||
87 | </funcsynopsis> | |
88 | </refsynopsisdiv> | |
89 | ||
90 | <refsect1> | |
91 | <title>Description</title> | |
92 | ||
93 | <para><function>sd_is_fifo()</function> may be called to check | |
94 | whether the specified file descriptor refers to a FIFO or pipe. If | |
95 | the <parameter>path</parameter> parameter is not | |
96 | <constant>NULL</constant>, it is checked whether the FIFO is bound | |
97 | to the specified file system path.</para> | |
98 | ||
99 | <para><function>sd_is_socket()</function> may be called to check | |
100 | whether the specified file descriptor refers to a socket. If the | |
101 | <parameter>family</parameter> parameter is not | |
102 | <constant>AF_UNSPEC</constant>, it is checked whether the socket | |
de737be0 | 103 | is of the specified family (<constant>AF_UNIX</constant>, |
1eecafb8 | 104 | <constant>AF_INET</constant>, …). If the <parameter>type</parameter> |
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105 | parameter is not 0, it is checked whether the socket is of the |
106 | specified type (<constant>SOCK_STREAM</constant>, | |
1eecafb8 | 107 | <constant>SOCK_DGRAM</constant>, …). If the |
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108 | <parameter>listening</parameter> parameter is positive, it is |
109 | checked whether the socket is in accepting mode, i.e. | |
110 | <function>listen()</function> has been called for it. If | |
111 | <parameter>listening</parameter> is 0, it is checked whether the | |
112 | socket is not in this mode. If the parameter is negative, no such | |
113 | check is made. The <parameter>listening</parameter> parameter | |
114 | should only be used for stream sockets and should be set to a | |
115 | negative value otherwise.</para> | |
116 | ||
117 | <para><function>sd_is_socket_inet()</function> is similar to | |
118 | <function>sd_is_socket()</function>, but optionally checks the | |
119 | IPv4 or IPv6 port number the socket is bound to, unless | |
120 | <parameter>port</parameter> is zero. For this call | |
121 | <parameter>family</parameter> must be passed as either | |
122 | <constant>AF_UNSPEC</constant>, <constant>AF_INET</constant>, or | |
123 | <constant>AF_INET6</constant>.</para> | |
124 | ||
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125 | <para><function>sd_is_socket_sockaddr()</function> is similar to |
126 | <function>sd_is_socket_inet()</function>, but checks if the socket is bound to the | |
127 | address specified by <parameter>addr</parameter>. The | |
128 | <structfield>family</structfield> specified by <parameter>addr</parameter> must be | |
129 | either <constant>AF_INET</constant> or <constant>AF_INET6</constant> and | |
130 | <parameter>addr_len</parameter> must be large enough for that family. If | |
131 | <parameter>addr</parameter> specifies a non-zero port, it is also checked if the | |
132 | socket is bound to this port. In addition, for IPv6, if <parameter>addr</parameter> | |
133 | specifies non-zero <structfield>sin6_flowinfo</structfield> or | |
134 | <structfield>sin6_scope_id</structfield>, it is checked if the socket has the same | |
135 | values.</para> | |
136 | ||
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137 | <para><function>sd_is_socket_unix()</function> is similar to |
138 | <function>sd_is_socket()</function> but optionally checks the | |
139 | <constant>AF_UNIX</constant> path the socket is bound to, unless | |
140 | the <parameter>path</parameter> parameter is | |
141 | <constant>NULL</constant>. For normal file system | |
142 | <constant>AF_UNIX</constant> sockets, set the | |
143 | <parameter>length</parameter> parameter to 0. For Linux abstract | |
144 | namespace sockets, set the <parameter>length</parameter> to the | |
145 | size of the address, including the initial 0 byte, and set the | |
146 | <parameter>path</parameter> to the initial 0 byte of the socket | |
147 | address.</para> | |
148 | ||
149 | <para><function>sd_is_mq()</function> may be called to check | |
150 | whether the specified file descriptor refers to a POSIX message | |
151 | queue. If the <parameter>path</parameter> parameter is not | |
152 | <constant>NULL</constant>, it is checked whether the message queue | |
153 | is bound to the specified name.</para> | |
154 | ||
155 | <para><function>sd_is_special()</function> may be called to check | |
156 | whether the specified file descriptor refers to a special file. If | |
157 | the <parameter>path</parameter> parameter is not | |
158 | <constant>NULL</constant>, it is checked whether the file | |
1245e413 | 159 | descriptor is bound to the specified filename. Special files in |
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160 | this context are character device nodes and files in |
161 | <filename>/proc</filename> or <filename>/sys</filename>.</para> | |
162 | </refsect1> | |
163 | ||
164 | <refsect1> | |
165 | <title>Return Value</title> | |
166 | ||
167 | <para>On failure, these calls return a negative errno-style error | |
168 | code. If the file descriptor is of the specified type and bound to | |
169 | the specified address, a positive return value is returned, | |
170 | otherwise zero.</para> | |
171 | </refsect1> | |
172 | ||
173 | <refsect1> | |
174 | <title>Notes</title> | |
175 | ||
176 | <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/> | |
177 | ||
178 | <para>Internally, these function use a combination of | |
179 | <filename>fstat()</filename> and | |
180 | <filename>getsockname()</filename> to check the file descriptor | |
181 | type and where it is bound to.</para> | |
182 | </refsect1> | |
183 | ||
184 | <refsect1> | |
185 | <title>See Also</title> | |
186 | <para> | |
187 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
188 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
189 | <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
190 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
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191 | <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
192 | <citerefentry project='man-pages'><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
193 | <citerefentry project='man-pages'><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
194 | <citerefentry project='man-pages'><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
195 | <citerefentry project='man-pages'><refentrytitle>fifo</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
196 | <citerefentry project='man-pages'><refentrytitle>mq_overview</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
197 | <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>. | |
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198 | </para> |
199 | </refsect1> | |
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200 | |
201 | </refentry> |