1
2 /**
3 * \file pgusage.c
4 *
5 * Automated Options Paged Usage module.
6 *
7 * @addtogroup autoopts
8 * @{
9 */
10 /*
11 * This routine will run run-on options through a pager so the
12 * user may examine, print or edit them at their leisure.
13 *
14 * This file is part of AutoOpts, a companion to AutoGen.
15 * AutoOpts is free software.
16 * AutoOpts is Copyright (C) 1992-2018 by Bruce Korb - all rights reserved
17 *
18 * AutoOpts is available under any one of two licenses. The license
19 * in use must be one of these two and the choice is under the control
20 * of the user of the license.
21 *
22 * The GNU Lesser General Public License, version 3 or later
23 * See the files "COPYING.lgplv3" and "COPYING.gplv3"
24 *
25 * The Modified Berkeley Software Distribution License
26 * See the file "COPYING.mbsd"
27 *
28 * These files have the following sha256 sums:
29 *
30 * 8584710e9b04216a394078dc156b781d0b47e1729104d666658aecef8ee32e95 COPYING.gplv3
31 * 4379e7444a0e2ce2b12dd6f5a52a27a4d02d39d247901d3285c88cf0d37f477b COPYING.lgplv3
32 * 13aa749a5b0a454917a944ed8fffc530b784f5ead522b1aacaf4ec8aa55a6239 COPYING.mbsd
33 */
34
35 #if defined(HAVE_WORKING_FORK)
36 static inline FILE *
open_tmp_usage(char ** buf)37 open_tmp_usage(char ** buf)
38 {
39 char * bf;
40 size_t bfsz;
41
42 {
43 unsigned int my_pid = (unsigned int)getpid();
44 char const * tmpdir = getenv(TMPDIR);
45 if (tmpdir == NULL)
46 tmpdir = tmp_dir;
47 bfsz = TMP_FILE_FMT_LEN + strlen(tmpdir) + 10;
48 bf = AGALOC(bfsz, "tmp fil");
49 snprintf(bf, bfsz, TMP_FILE_FMT, tmpdir, my_pid);
50 }
51
52 {
53 static mode_t const cmask = S_IRWXO | S_IRWXG;
54 mode_t svmsk = umask(cmask);
55 int fd = mkstemp(bf);
56 (void)umask(svmsk);
57
58 if (fd < 0) {
59 AGFREE(bf);
60 return NULL;
61 }
62 *buf = bf;
63 return fdopen(fd, "w");
64 }
65 }
66
67 static inline char *
mk_pager_cmd(char const * fname)68 mk_pager_cmd(char const * fname)
69 {
70 /*
71 * Page the file and remove it when done. For shell script processing,
72 * we must redirect the output to the current stderr, otherwise stdout.
73 */
74 fclose(option_usage_fp);
75 option_usage_fp = NULL;
76
77 {
78 char const * pager = (char const *)getenv(PAGER_NAME);
79 size_t bfsz;
80 char * res;
81
82 /*
83 * Use the "more(1)" program if "PAGER" has not been defined
84 */
85 if (pager == NULL)
86 pager = MORE_STR;
87
88 bfsz = 2 * strlen(fname) + strlen(pager) + PAGE_USAGE_FMT_LEN;
89 res = AGALOC(bfsz, "more cmd");
90 snprintf(res, bfsz, PAGE_USAGE_FMT, pager, fname);
91 AGFREE(fname);
92 return res;
93 }
94 }
95 #endif
96
97 /*=export_func optionPagedUsage
98 * private:
99 *
100 * what: emit help text and pass through a pager program.
101 * arg: + tOptions * + opts + program options descriptor +
102 * arg: + tOptDesc * + od + the descriptor for this arg +
103 *
104 * doc:
105 * Run the usage output through a pager.
106 * This is very handy if it is very long.
107 * This is disabled on platforms without a working fork() function.
108 =*/
109 void
optionPagedUsage(tOptions * opts,tOptDesc * od)110 optionPagedUsage(tOptions * opts, tOptDesc * od)
111 {
112 #if ! defined(HAVE_WORKING_FORK)
113 if ((od->fOptState & OPTST_RESET) != 0)
114 return;
115
116 (*opts->pUsageProc)(opts, EXIT_SUCCESS);
117 #else
118 static bool sv_print_exit = false;
119 static char * fil_name = NULL;
120
121 /*
122 * IF we are being called after the usage proc is done
123 * (and thus has called "exit(2)")
124 * THEN invoke the pager to page through the usage file we created.
125 */
126 switch (pagerState) {
127 case PAGER_STATE_INITIAL:
128 {
129 if ((od->fOptState & OPTST_RESET) != 0)
130 return;
131 option_usage_fp = open_tmp_usage(&fil_name);
132 if (option_usage_fp == NULL)
133 (*opts->pUsageProc)(opts, EXIT_SUCCESS);
134
135 pagerState = PAGER_STATE_READY;
136 sv_print_exit = print_exit;
137
138 /*
139 * Set up so this routine gets called during the exit logic
140 */
141 atexit((void(*)(void))optionPagedUsage);
142
143 /*
144 * The usage procedure will now put the usage information into
145 * the temporary file we created above. Keep any shell commands
146 * out of the result.
147 */
148 print_exit = false;
149 (*opts->pUsageProc)(opts, EXIT_SUCCESS);
150
151 /* NOTREACHED */
152 _exit(EXIT_FAILURE);
153 }
154
155 case PAGER_STATE_READY:
156 fil_name = mk_pager_cmd(fil_name);
157
158 if (sv_print_exit) {
159 fputs("\nexit 0\n", stdout);
160 fclose(stdout);
161 dup2(STDERR_FILENO, STDOUT_FILENO);
162
163 } else {
164 fclose(stderr);
165 dup2(STDOUT_FILENO, STDERR_FILENO);
166 }
167
168 ignore_val( system( fil_name));
169 AGFREE(fil_name);
170
171 case PAGER_STATE_CHILD:
172 /*
173 * This is a child process used in creating shell script usage.
174 */
175 break;
176 }
177 #endif
178 }
179
180 /** @}
181 *
182 * Local Variables:
183 * mode: C
184 * c-file-style: "stroustrup"
185 * indent-tabs-mode: nil
186 * End:
187 * end of autoopts/pgusage.c */
188