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
|
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta http-equiv="Content-Language" content="en" />
<title>nsss: the nsssd library interface</title>
<meta name="Description" content="nsss: the nsssd library interface" />
<meta name="Keywords" content="NSS pwd group shadow library backend nsssd daemon libnsssd skarnet" />
<!-- <link rel="stylesheet" type="text/css" href="//skarnet.org/default.css" /> -->
</head>
<body>
<p>
<a href="../">nsss</a><br />
<a href="//skarnet.org/software/">Software</a><br />
<a href="//skarnet.org/">skarnet.org</a>
</p>
<h1> The <tt>nsssd</tt> library interface </h1>
<h2> General information </h2>
<p>
<tt>libnsssd</tt> is a library that can be used by external applications
to implement extra nsss backends, in the style of
<a href="../nsssd-unix.html">nsssd-unix</a> and
<a href="../nsssd-nslcd.html">nsssd-nslcd</a>, without learning the
details of the nsss protocol or having to perform IO themselves.
</p>
<h2> Compiling </h2>
<ul>
<li> Make sure the nsss headers, as well as the skalibs headers,
are visible in your header search path. </li>
<li> Use <tt>#include <skalibs/strerr2.h></tt> and
<tt>#include <nsss/nsssd.h></tt> </li>
</ul>
<h2> Linking </h2>
<ul>
<li> Make sure the nsssd library, as well as the skalibs library,
are visible in your library search path. </li>
<li> Link against <tt>-lnsssd</tt>, <tt>-lskarnet</tt>, </li>
<tt>`cat $SYSDEPS/socket.lib`</tt> and
<tt>`cat $SYSDEPS/tainnow.lib`</tt>, $SYSDEPS being your skalibs
sysdeps directory. </li>
</ul>
<h2> Programming </h2>
<ul>
<li> In your <tt>main()</tt> function, start with assigning
the name of your program to the PROG variable. Example:
<tt>PROG = "nsssd-foobar";</tt> </li>
<li> Your <tt>main()</tt> function can parse options and
take command line arguments as it sees fit. But once it's done
parsing options, give control to the <tt>nsssd_main()</tt>
function, using your <em>argv</em> and <em>envp</em> as
arguments: <tt>return nsssd_main(argv, envp);</tt> </li>
</ul>
<p>
The rest of your program should implement the functions needed by
<tt>nsssd_main()</tt>. Here is what those functions are:
</p>
<h4><code>void *nsssd_handle_init (void)</code></h4>
<p>
This function must return a pointer to an <em>uninitialized</em>
handle. The handle can be whatever you need to implement your
backend; the pointer to your handle will be passed to every
subsequent function. The function must not return NULL.
</p>
<h4><code>int nsssd_handle_start (void *handle, char const *const *argv, char const *const *envp)</code></h4>
<p>
This function must <em>initialize the handle</em>. The arguments
it receives are the <em>argv</em> and <em>envp</em> that have been
passed to <tt>nsssd_main()</tt>. This allows you to write daemons
that can be somewhat configured via the command line: it is how
<a href="../nsssd-nslcd.html">nsssd-nslcd</a> takes an argument
telling it where the nslcd socket is, and uses that argument in
its own <tt>nsssd_handle_start</tt> to actually connect to the
nslcd daemon. <br />
The function must return nonzero if it succeeds, and 0 if it
fails, setting errno appropriately.
</p>
<h4><code>void nsssd_handle_end (void *handle)</code></h4>
<p>
This function must deinitialize the handle and free all
related resources: close connections to external processes, etc.
</p>
<p>
TODO: to be completed.
</p>
</body>
</html>
|
