pgusage.c revision 1.1.1.2 
1117397Skan/*	$NetBSD: pgusage.c,v 1.1.1.2 2012/01/31 21:27:52 kardel Exp $	*/
2117397Skan
3117397Skan
4117397Skan/**
5117397Skan * \file pgusage.c
6117397Skan *
7117397Skan * Time-stamp:      "2011-03-25 17:54:41 bkorb"
8117397Skan *
9117397Skan *   Automated Options Paged Usage module.
10117397Skan *
11117397Skan *  This routine will run run-on options through a pager so the
12117397Skan *  user may examine, print or edit them at their leisure.
13117397Skan *
14117397Skan *  This file is part of AutoOpts, a companion to AutoGen.
15117397Skan *  AutoOpts is free software.
16117397Skan *  AutoOpts is Copyright (c) 1992-2011 by Bruce Korb - all rights reserved
17117397Skan *
18169691Skan *  AutoOpts is available under any one of two licenses.  The license
19117397Skan *  in use must be one of these two and the choice is under the control
20117397Skan *  of the user of the license.
21117397Skan *
22117397Skan *   The GNU Lesser General Public License, version 3 or later
23117397Skan *      See the files "COPYING.lgplv3" and "COPYING.gplv3"
24117397Skan *
25117397Skan *   The Modified Berkeley Software Distribution License
26117397Skan *      See the file "COPYING.mbsd"
27117397Skan *
28117397Skan *  These files have the following md5sums:
29169691Skan *
30169691Skan *  43b91e8ca915626ed3818ffb1b71248b pkg/libopts/COPYING.gplv3
31169691Skan *  06a1a2e4760c90ea5e1dad8dfaac4d39 pkg/libopts/COPYING.lgplv3
32169691Skan *  66a5cedaf62c4b2637025f049f9b826f pkg/libopts/COPYING.mbsd
33169691Skan */
34117397Skan
35117397Skan/*=export_func  optionPagedUsage
36117397Skan * private:
37117397Skan *
38169691Skan * what:  Decipher a boolean value
39117397Skan * arg:   + tOptions* + pOpts    + program options descriptor +
40117397Skan * arg:   + tOptDesc* + pOptDesc + the descriptor for this arg +
41117397Skan *
42169691Skan * doc:
43169691Skan *  Run the usage output through a pager.
44117397Skan *  This is very handy if it is very long.
45117397Skan *  This is disabled on platforms without a working fork() function.
46117397Skan=*/
47117397Skanvoid
48117397SkanoptionPagedUsage(tOptions* pOptions, tOptDesc* pOD)
49117397Skan{
50117397Skan#if ! defined(HAVE_WORKING_FORK)
51117397Skan    if ((pOD->fOptState & OPTST_RESET) != 0)
52117397Skan        return;
53117397Skan
54117397Skan    (*pOptions->pUsageProc)(pOptions, EXIT_SUCCESS);
55117397Skan#else
56117397Skan    static pid_t     my_pid;
57117397Skan    char zPageUsage[ 1024 ];
58117397Skan
59117397Skan    /*
60117397Skan     *  IF we are being called after the usage proc is done
61117397Skan     *     (and thus has called "exit(2)")
62117397Skan     *  THEN invoke the pager to page through the usage file we created.
63117397Skan     */
64117397Skan    switch (pagerState) {
65117397Skan    case PAGER_STATE_INITIAL:
66117397Skan    {
67117397Skan        if ((pOD->fOptState & OPTST_RESET) != 0)
68117397Skan            return;
69117397Skan
70117397Skan        my_pid  = getpid();
71117397Skan#ifdef HAVE_SNPRINTF
72117397Skan        snprintf(zPageUsage, sizeof(zPageUsage), "/tmp/use.%lu", (tAoUL)my_pid);
73117397Skan#else
74117397Skan        sprintf(zPageUsage, "/tmp/use.%lu", (tAoUL)my_pid);
75117397Skan#endif
76117397Skan        unlink(zPageUsage);
77169691Skan
78169691Skan        /*
79         *  Set usage output to this temporary file
80         */
81        option_usage_fp = fopen(zPageUsage, "w" FOPEN_BINARY_FLAG);
82        if (option_usage_fp == NULL)
83            _exit(EXIT_FAILURE);
84
85        pagerState = PAGER_STATE_READY;
86
87        /*
88         *  Set up so this routine gets called during the exit logic
89         */
90        atexit((void(*)(void))optionPagedUsage);
91
92        /*
93         *  The usage procedure will now put the usage information into
94         *  the temporary file we created above.
95         */
96        (*pOptions->pUsageProc)(pOptions, EXIT_SUCCESS);
97
98        /* NOTREACHED */
99        _exit(EXIT_FAILURE);
100    }
101
102    case PAGER_STATE_READY:
103    {
104        tSCC zPage[]  = "%1$s /tmp/use.%2$lu ; rm -f /tmp/use.%2$lu";
105        tCC* pzPager  = (tCC*)getenv("PAGER");
106
107        /*
108         *  Use the "more(1)" program if "PAGER" has not been defined
109         */
110        if (pzPager == NULL)
111            pzPager = "more";
112
113        /*
114         *  Page the file and remove it when done.
115         */
116#ifdef HAVE_SNPRINTF
117        snprintf(zPageUsage, sizeof(zPageUsage), zPage, pzPager, (tAoUL)my_pid);
118#else
119        sprintf(zPageUsage, zPage, pzPager, (tAoUL)my_pid);
120#endif
121        fclose(stderr);
122        dup2(STDOUT_FILENO, STDERR_FILENO);
123
124        (void)system(zPageUsage);
125    }
126
127    case PAGER_STATE_CHILD:
128        /*
129         *  This is a child process used in creating shell script usage.
130         */
131        break;
132    }
133#endif
134}
135
136/*
137 * Local Variables:
138 * mode: C
139 * c-file-style: "stroustrup"
140 * indent-tabs-mode: nil
141 * End:
142 * end of autoopts/pgusage.c */
143