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<HTML><HEAD><TITLE>Manpage of IPSEC_OPTIONSFROM</TITLE>
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<H1>IPSEC_OPTIONSFROM</H1>
Section: C Library Functions (3)<BR>Updated: 16 Oct 1998<BR><A HREF="#index">Index</A>
<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>


<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>

ipsec optionsfrom - read additional ``command-line'' options from file
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>

<B>#include &lt;<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>&gt;</B>

<P>
<B>const char *optionsfrom(char *filename, int *argcp,</B>

<BR>
&nbsp;
<B>char ***argvp, int optind, FILE *errsto);</B>

<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>

<I>Optionsfrom</I>

is called from within a
<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)

scan,
as the result of the appearance of an option (preferably
<B>--optionsfrom</B>)

to insert additional ``command-line'' arguments
into the scan immediately after
the option.
Typically this would be done to pick up options which are
security-sensitive and should not be visible to
<I><A HREF="ps.1.html">ps</A></I>(1)

and similar commands,
and hence cannot be supplied as part
of the actual command line or the environment.
<P>

<I>Optionsfrom</I>

reads the additional arguments from the specified
<I>filename</I>,

allocates a new argument vector to hold pointers to the existing
arguments plus the new ones,
and amends
<I>argc</I>

and
<I>argv</I>

(via the pointers
<I>argcp</I>

and
<I>argvp</I>,

which must point to the
<I>argc</I>

and
<I>argv</I>

being supplied to
<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3))

accordingly.
<I>Optind</I>

must be the index, in the original argument vector,
of the next argument.
<P>

If
<I>errsto</I>

is NULL,
<I>optionsfrom</I>

returns NULL for success and
a pointer to a string-literal error message for failure;
see DIAGNOSTICS.
If
<I>errsto</I>

is non-NULL and an error occurs,
<I>optionsfrom</I>

prints a suitable complaint onto the
<I>errsto</I>

descriptor and invokes
<I>exit</I>

with an exit status of 2;
this is a convenience for cases where more sophisticated
responses are not required.
<P>

The text of existing arguments is not disturbed by
<I>optionsfrom</I>,

so pointers to them and into them remain valid.
<P>

The file of additional arguments is an ASCII text file.
Lines consisting solely of white space,
and lines beginning with
<B>#</B>,

are comments and are ignored.
Otherwise, a line which does not begin with
<B>-</B>

is taken to be a single argument;
if it both begins and ends with double-quote (&quot;),
those quotes are stripped off (note, no other processing is done within
the line!).
A line beginning with
<B>-</B>

is considered to contain multiple arguments separated by white space.
<P>

Because
<I>optionsfrom</I>

reads its entire file before the
<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)

scan is resumed, an
<I>optionsfrom</I>

file can contain another
<B>--optionsfrom</B>

option.
Obviously, infinite loops are possible here.
If
<I>errsto</I>

is non-NULL,
<I>optionsfrom</I>

considers it an error to be called more than 100 times.
If
<I>errsto</I>

is NULL,
loop detection is up to the caller
(and the internal loop counter is zeroed out).
<A NAME="lbAE">&nbsp;</A>
<H2>EXAMPLE</H2>

A reasonable way to invoke
<I>optionsfrom</I>

would be like so:
<P>

<PRE>
<B>#include &lt;<A HREF="file:/usr/include/getopt.h">getopt.h</A>&gt;

struct option opts[] = {
        /* ... */
        &quot;optionsfrom&quot;,  1,      NULL,   '+',
        /* ... */
};

int
main(argc, argv)
int argc;
char *argv[];
{
        int opt;
        extern char *optarg;
        extern int optind;

        while ((opt = getopt_long(argc, argv, &quot;&quot;, opts, NULL)) != EOF)
                switch (opt) {
                /* ... */
                case '+':       /* optionsfrom */
                        optionsfrom(optarg, &amp;argc, &amp;argv, optind, stderr);
                        /* does not return on error */
                        break;
                /* ... */
                }
        /* ... */
</B></PRE>

<A NAME="lbAF">&nbsp;</A>
<H2>SEE ALSO</H2>

<A HREF="getopt_long.3.html">getopt_long</A>(3)
<A NAME="lbAG">&nbsp;</A>
<H2>DIAGNOSTICS</H2>

Errors in
<I>optionsfrom</I>

are:
unable to open file;
attempt to allocate temporary storage for argument or
argument vector failed;
read error in file;
line too long.
<A NAME="lbAH">&nbsp;</A>
<H2>HISTORY</H2>

Written for the FreeS/WAN project by Henry Spencer.
<A NAME="lbAI">&nbsp;</A>
<H2>BUGS</H2>

The double-quote convention is rather simplistic.
<P>

Line length is currently limited to 1023 bytes,
and there is no continuation convention.
<P>

The restriction of error reports to literal strings
(so that callers don't need to worry about freeing them or copying them)
does limit the precision of error reporting.
<P>

The error-reporting convention lends itself
to slightly obscure code,
because many readers will not think of NULL as signifying success.
<P>

There is a certain element of unwarranted chumminess with
the insides of
<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)

here.
No non-public interfaces are actually used, but
<I>optionsfrom</I>

does rely on
<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)

being well-behaved in certain ways that are not actually
promised by the specs.
<P>

<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT><A HREF="#lbAB">NAME</A><DD>
<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT><A HREF="#lbAE">EXAMPLE</A><DD>
<DT><A HREF="#lbAF">SEE ALSO</A><DD>
<DT><A HREF="#lbAG">DIAGNOSTICS</A><DD>
<DT><A HREF="#lbAH">HISTORY</A><DD>
<DT><A HREF="#lbAI">BUGS</A><DD>
</DL>
<HR>
This document was created by
<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
using the manual pages.<BR>
Time: 21:40:18 GMT, November 11, 2003
</BODY>
</HTML>
Commit	Line	Data
997358a6 MW	1	Content-type: text/html
	2
	3	<HTML><HEAD><TITLE>Manpage of IPSEC_OPTIONSFROM</TITLE>
	4	</HEAD><BODY>
	5	<H1>IPSEC_OPTIONSFROM</H1>
	6	Section: C Library Functions (3)<BR>Updated: 16 Oct 1998<BR><A HREF="#index">Index</A>
	7	<A HREF="http://localhost/cgi-bin/man/man2html">Return to Main Contents</A><HR>
	8
	9
	10	<A NAME="lbAB"> </A>
	11	<H2>NAME</H2>
	12
	13	ipsec optionsfrom - read additional ``command-line'' options from file
	14	<A NAME="lbAC"> </A>
	15	<H2>SYNOPSIS</H2>
	16
	17	<B>#include <<A HREF="file:/usr/include/freeswan.h">freeswan.h</A>></B>
	18
	19	<P>
	20	<B>const char optionsfrom(char filename, int *argcp,</B>
	21
	22	<BR>
	23
	24	<B>char **argvp, int optind, FILE errsto);</B>
	25
	26	<A NAME="lbAD"> </A>
	27	<H2>DESCRIPTION</H2>
	28
	29	<I>Optionsfrom</I>
	30
	31	is called from within a
	32	<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
	33
	34	scan,
	35	as the result of the appearance of an option (preferably
	36	<B>--optionsfrom</B>)
	37
	38	to insert additional ``command-line'' arguments
	39	into the scan immediately after
	40	the option.
	41	Typically this would be done to pick up options which are
	42	security-sensitive and should not be visible to
	43	<I><A HREF="ps.1.html">ps</A></I>(1)
	44
	45	and similar commands,
	46	and hence cannot be supplied as part
	47	of the actual command line or the environment.
	48	<P>
	49
	50	<I>Optionsfrom</I>
	51
	52	reads the additional arguments from the specified
	53	<I>filename</I>,
	54
	55	allocates a new argument vector to hold pointers to the existing
	56	arguments plus the new ones,
	57	and amends
	58	<I>argc</I>
	59
	60	and
	61	<I>argv</I>
	62
	63	(via the pointers
	64	<I>argcp</I>
65
66	and
67	<I>argvp</I>,
68
69	which must point to the
70	<I>argc</I>
71
72	and
73	<I>argv</I>
74
75	being supplied to
76	<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3))
77
78	accordingly.
79	<I>Optind</I>
80
81	must be the index, in the original argument vector,
82	of the next argument.
83	<P>
84
85	If
86	<I>errsto</I>
87
88	is NULL,
89	<I>optionsfrom</I>
90
91	returns NULL for success and
92	a pointer to a string-literal error message for failure;
93	see DIAGNOSTICS.
94	If
95	<I>errsto</I>
96
97	is non-NULL and an error occurs,
98	<I>optionsfrom</I>
99
100	prints a suitable complaint onto the
101	<I>errsto</I>
102
103	descriptor and invokes
104	<I>exit</I>
105
106	with an exit status of 2;
107	this is a convenience for cases where more sophisticated
108	responses are not required.
109	<P>
110
111	The text of existing arguments is not disturbed by
112	<I>optionsfrom</I>,
113
114	so pointers to them and into them remain valid.
115	<P>
116
117	The file of additional arguments is an ASCII text file.
118	Lines consisting solely of white space,
119	and lines beginning with
120	<B>#</B>,
121
122	are comments and are ignored.
123	Otherwise, a line which does not begin with
124	<B>-</B>
125
126	is taken to be a single argument;
127	if it both begins and ends with double-quote ("),
128	those quotes are stripped off (note, no other processing is done within
129	the line!).
130	A line beginning with
131	<B>-</B>
132
133	is considered to contain multiple arguments separated by white space.
134	<P>
135
136	Because
137	<I>optionsfrom</I>
138
139	reads its entire file before the
140	<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
141
142	scan is resumed, an
143	<I>optionsfrom</I>
144
145	file can contain another
146	<B>--optionsfrom</B>
147
148	option.
149	Obviously, infinite loops are possible here.
150	If
151	<I>errsto</I>
152
153	is non-NULL,
154	<I>optionsfrom</I>
155
156	considers it an error to be called more than 100 times.
157	If
158	<I>errsto</I>
159
160	is NULL,
161	loop detection is up to the caller
162	(and the internal loop counter is zeroed out).
163	<A NAME="lbAE"> </A>
164	<H2>EXAMPLE</H2>
165
166	A reasonable way to invoke
167	<I>optionsfrom</I>
168
169	would be like so:
170	<P>
171
172	<PRE>
173	<B>#include <<A HREF="file:/usr/include/getopt.h">getopt.h</A>>
174
175	struct option opts[] = {
176	/* ... */
177	"optionsfrom", 1, NULL, '+',
178	/* ... */
179	};
180
181	int
182	main(argc, argv)
183	int argc;
184	char *argv[];
185	{
186	int opt;
187	extern char *optarg;
188	extern int optind;
189
190	while ((opt = getopt_long(argc, argv, "", opts, NULL)) != EOF)
191	switch (opt) {
192	/* ... */
193	case '+': /* optionsfrom */
194	optionsfrom(optarg, &argc, &argv, optind, stderr);
195	/* does not return on error */
196	break;
197	/* ... */
198	}
199	/* ... */
200	</B></PRE>
201
202	<A NAME="lbAF"> </A>
203	<H2>SEE ALSO</H2>
204
205	<A HREF="getopt_long.3.html">getopt_long</A>(3)
206	<A NAME="lbAG"> </A>
207	<H2>DIAGNOSTICS</H2>
208
209	Errors in
210	<I>optionsfrom</I>
211
212	are:
213	unable to open file;
214	attempt to allocate temporary storage for argument or
215	argument vector failed;
216	read error in file;
217	line too long.
218	<A NAME="lbAH"> </A>
219	<H2>HISTORY</H2>
220
221	Written for the FreeS/WAN project by Henry Spencer.
222	<A NAME="lbAI"> </A>
223	<H2>BUGS</H2>
224
225	The double-quote convention is rather simplistic.
226	<P>
227
228	Line length is currently limited to 1023 bytes,
229	and there is no continuation convention.
230	<P>
231
232	The restriction of error reports to literal strings
233	(so that callers don't need to worry about freeing them or copying them)
234	does limit the precision of error reporting.
235	<P>
236
237	The error-reporting convention lends itself
238	to slightly obscure code,
239	because many readers will not think of NULL as signifying success.
240	<P>
241
242	There is a certain element of unwarranted chumminess with
243	the insides of
244	<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
245
246	here.
247	No non-public interfaces are actually used, but
248	<I>optionsfrom</I>
249
250	does rely on
251	<I><A HREF="getopt_long.3.html">getopt_long</A></I>(3)
252
253	being well-behaved in certain ways that are not actually
254	promised by the specs.
255	<P>
256
257	<HR>
258	<A NAME="index"> </A><H2>Index</H2>
259	<DL>
260	<DT><A HREF="#lbAB">NAME</A><DD>
261	<DT><A HREF="#lbAC">SYNOPSIS</A><DD>
262	<DT><A HREF="#lbAD">DESCRIPTION</A><DD>
263	<DT><A HREF="#lbAE">EXAMPLE</A><DD>
264	<DT><A HREF="#lbAF">SEE ALSO</A><DD>
265	<DT><A HREF="#lbAG">DIAGNOSTICS</A><DD>
266	<DT><A HREF="#lbAH">HISTORY</A><DD>
267	<DT><A HREF="#lbAI">BUGS</A><DD>
268	</DL>
269	<HR>
270	This document was created by
271	<A HREF="http://localhost/cgi-bin/man/man2html">man2html</A>,
272	using the manual pages.<BR>
273	Time: 21:40:18 GMT, November 11, 2003
274	</BODY>
275	</HTML>