aboutsummaryrefslogtreecommitdiff
path: root/sntp/libopts/pgusage.c
blob: 80a89a713d47123c84b82bb649619915dedfe429 (plain) (blame)
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

/**
 * \file pgusage.c
 *
 *   Automated Options Paged Usage module.
 *
 * @addtogroup autoopts
 * @{
 */
/*
 *  This routine will run run-on options through a pager so the
 *  user may examine, print or edit them at their leisure.
 *
 *  This file is part of AutoOpts, a companion to AutoGen.
 *  AutoOpts is free software.
 *  AutoOpts is Copyright (C) 1992-2014 by Bruce Korb - all rights reserved
 *
 *  AutoOpts is available under any one of two licenses.  The license
 *  in use must be one of these two and the choice is under the control
 *  of the user of the license.
 *
 *   The GNU Lesser General Public License, version 3 or later
 *      See the files "COPYING.lgplv3" and "COPYING.gplv3"
 *
 *   The Modified Berkeley Software Distribution License
 *      See the file "COPYING.mbsd"
 *
 *  These files have the following sha256 sums:
 *
 *  8584710e9b04216a394078dc156b781d0b47e1729104d666658aecef8ee32e95  COPYING.gplv3
 *  4379e7444a0e2ce2b12dd6f5a52a27a4d02d39d247901d3285c88cf0d37f477b  COPYING.lgplv3
 *  13aa749a5b0a454917a944ed8fffc530b784f5ead522b1aacaf4ec8aa55a6239  COPYING.mbsd
 */

#if defined(HAVE_WORKING_FORK)
static FILE *
open_tmp_usage(char ** buf)
{
    char * bf;
    size_t bfsz;

    {
        unsigned int my_pid = (unsigned int)getpid();
        char const * tmpdir = getenv(TMPDIR);
        if (tmpdir == NULL)
            tmpdir = tmp_dir;
        bfsz = TMP_FILE_FMT_LEN + strlen(tmpdir) + 10;
        bf   = AGALOC(bfsz, "tmp fil");
        snprintf(bf, bfsz, TMP_FILE_FMT, tmpdir, my_pid);
    }

    {
        static mode_t const cmask = S_IRWXO | S_IRWXG;
        mode_t svmsk = umask(cmask);
        int fd = mkstemp(bf);
        (void)umask(svmsk);

        if (fd < 0) {
            AGFREE(bf);
            return NULL;
        }
        *buf = bf;
        return fdopen(fd, "w");
    }
}

static char *
mk_pager_cmd(char const * fname)
{
    /*
     * Page the file and remove it when done.  For shell script processing,
     * we must redirect the output to the current stderr, otherwise stdout.
     */
    fclose(option_usage_fp);
    option_usage_fp = NULL;

    {
        char const * pager  = (char const *)getenv(PAGER_NAME);
        size_t bfsz;
        char * res;

        /*
         *  Use the "more(1)" program if "PAGER" has not been defined
         */
        if (pager == NULL)
            pager = MORE_STR;

        bfsz = strlen(fname) + strlen(pager) + PAGE_USAGE_FMT_LEN;
        res  = AGALOC(bfsz, "more cmd");
        snprintf(res, bfsz, PAGE_USAGE_FMT, pager, fname);
        AGFREE((void*)fname);
        return res;
    }
}
#endif

/*=export_func  optionPagedUsage
 * private:
 *
 * what:  emit help text and pass through a pager program.
 * arg:   + tOptions * + opts + program options descriptor +
 * arg:   + tOptDesc * + od   + the descriptor for this arg +
 *
 * doc:
 *  Run the usage output through a pager.
 *  This is very handy if it is very long.
 *  This is disabled on platforms without a working fork() function.
=*/
void
optionPagedUsage(tOptions * opts, tOptDesc * od)
{
#if ! defined(HAVE_WORKING_FORK)
    if ((od->fOptState & OPTST_RESET) != 0)
        return;

    (*opts->pUsageProc)(opts, EXIT_SUCCESS);
#else
    static bool sv_print_exit = false;
    static char * fil_name = NULL;

    /*
     *  IF we are being called after the usage proc is done
     *     (and thus has called "exit(2)")
     *  THEN invoke the pager to page through the usage file we created.
     */
    switch (pagerState) {
    case PAGER_STATE_INITIAL:
    {
        if ((od->fOptState & OPTST_RESET) != 0)
            return;
        option_usage_fp = open_tmp_usage(&fil_name);
        if (option_usage_fp == NULL)
            (*opts->pUsageProc)(opts, EXIT_SUCCESS);

        pagerState    = PAGER_STATE_READY;
        sv_print_exit = print_exit;

        /*
         *  Set up so this routine gets called during the exit logic
         */
        atexit((void(*)(void))optionPagedUsage);

        /*
         *  The usage procedure will now put the usage information into
         *  the temporary file we created above.  Keep any shell commands
         *  out of the result.
         */
        print_exit = false;
        (*opts->pUsageProc)(opts, EXIT_SUCCESS);

        /* NOTREACHED */
        _exit(EXIT_FAILURE);
    }

    case PAGER_STATE_READY:
        fil_name = mk_pager_cmd(fil_name);

        if (sv_print_exit) {
            fputs("\nexit 0\n", stdout);
            fclose(stdout);
            dup2(STDERR_FILENO, STDOUT_FILENO);

        } else {
            fclose(stderr);
            dup2(STDOUT_FILENO, STDERR_FILENO);
        }

        ignore_val( system( fil_name));
        AGFREE(fil_name);

    case PAGER_STATE_CHILD:
        /*
         *  This is a child process used in creating shell script usage.
         */
        break;
    }
#endif
}

/** @}
 *
 * Local Variables:
 * mode: C
 * c-file-style: "stroustrup"
 * indent-tabs-mode: nil
 * End:
 * end of autoopts/pgusage.c */