1 /****************************************************************************
2 * Copyright 2018,2020 Thomas E. Dickey *
3 * Copyright 2006-2016,2017 Free Software Foundation, Inc. *
4 * *
5 * Permission is hereby granted, free of charge, to any person obtaining a *
6 * copy of this software and associated documentation files (the *
7 * "Software"), to deal in the Software without restriction, including *
8 * without limitation the rights to use, copy, modify, merge, publish, *
9 * distribute, distribute with modifications, sublicense, and/or sell *
10 * copies of the Software, and to permit persons to whom the Software is *
11 * furnished to do so, subject to the following conditions: *
12 * *
13 * The above copyright notice and this permission notice shall be included *
14 * in all copies or substantial portions of the Software. *
15 * *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
23 * *
24 * Except as contained in this notice, the name(s) of the above copyright *
25 * holders shall not be used in advertising or otherwise to promote the *
26 * sale, use or other dealings in this Software without prior written *
27 * authorization. *
28 ****************************************************************************/
29
30 /****************************************************************************
31 * Author: Thomas E. Dickey *
32 ****************************************************************************/
33
34 /*
35 * Iterators for terminal databases.
36 */
37
38 #include <curses.priv.h>
39
40 #include <time.h>
41 #include <tic.h>
42
43 #if USE_HASHED_DB
44 #include <hashed_db.h>
45 #endif
46
47 MODULE_ID("$Id: db_iterator.c,v 1.48 2020/02/02 23:34:34 tom Exp $")
48
49 #define HaveTicDirectory _nc_globals.have_tic_directory
50 #define KeepTicDirectory _nc_globals.keep_tic_directory
51 #define TicDirectory _nc_globals.tic_directory
52 #define my_blob _nc_globals.dbd_blob
53 #define my_list _nc_globals.dbd_list
54 #define my_size _nc_globals.dbd_size
55 #define my_time _nc_globals.dbd_time
56 #define my_vars _nc_globals.dbd_vars
57
58 static void
add_to_blob(const char * text,size_t limit)59 add_to_blob(const char *text, size_t limit)
60 {
61 (void) limit;
62
63 if (*text != '\0') {
64 char *last = my_blob + strlen(my_blob);
65 if (last != my_blob)
66 *last++ = NCURSES_PATHSEP;
67 _nc_STRCPY(last, text, limit);
68 }
69 }
70
71 static bool
check_existence(const char * name,struct stat * sb)72 check_existence(const char *name, struct stat *sb)
73 {
74 bool result = FALSE;
75
76 if (quick_prefix(name)) {
77 result = TRUE;
78 } else if (stat(name, sb) == 0
79 && (S_ISDIR(sb->st_mode)
80 || (S_ISREG(sb->st_mode) && sb->st_size))) {
81 result = TRUE;
82 }
83 #if USE_HASHED_DB
84 else if (strlen(name) < PATH_MAX - sizeof(DBM_SUFFIX)) {
85 char temp[PATH_MAX];
86 _nc_SPRINTF(temp, _nc_SLIMIT(sizeof(temp)) "%s%s", name, DBM_SUFFIX);
87 if (stat(temp, sb) == 0 && S_ISREG(sb->st_mode) && sb->st_size) {
88 result = TRUE;
89 }
90 }
91 #endif
92 return result;
93 }
94
95 /*
96 * Trim newlines (and backslashes preceding those) and tab characters to
97 * help simplify scripting of the quick-dump feature. Leave spaces and
98 * other backslashes alone.
99 */
100 static void
trim_formatting(char * source)101 trim_formatting(char *source)
102 {
103 char *target = source;
104 char ch;
105
106 while ((ch = *source++) != '\0') {
107 if (ch == '\\' && *source == '\n')
108 continue;
109 if (ch == '\n' || ch == '\t')
110 continue;
111 *target++ = ch;
112 }
113 *target = '\0';
114 }
115
116 /*
117 * Store the latest value of an environment variable in my_vars[] so we can
118 * detect if one changes, invalidating the cached search-list.
119 */
120 static bool
update_getenv(const char * name,DBDIRS which)121 update_getenv(const char *name, DBDIRS which)
122 {
123 bool result = FALSE;
124
125 if (which < dbdLAST) {
126 char *value;
127 char *cached_value = my_vars[which].value;
128 bool same_value;
129
130 if ((value = getenv(name)) != 0) {
131 value = strdup(value);
132 }
133 same_value = ((value == 0 && cached_value == 0) ||
134 (value != 0 &&
135 cached_value != 0 &&
136 strcmp(value, cached_value) == 0));
137
138 /* Set variable name to enable checks in cache_expired(). */
139 my_vars[which].name = name;
140
141 if (!same_value) {
142 FreeIfNeeded(my_vars[which].value);
143 my_vars[which].value = value;
144 result = TRUE;
145 } else {
146 free(value);
147 }
148 }
149 return result;
150 }
151
152 #if NCURSES_USE_DATABASE || NCURSES_USE_TERMCAP
153 static char *
cache_getenv(const char * name,DBDIRS which)154 cache_getenv(const char *name, DBDIRS which)
155 {
156 char *result = 0;
157
158 (void) update_getenv(name, which);
159 if (which < dbdLAST) {
160 result = my_vars[which].value;
161 }
162 return result;
163 }
164 #endif
165
166 /*
167 * The cache expires if at least a second has passed since the initial lookup,
168 * or if one of the environment variables changed.
169 *
170 * Only a few applications use multiple lookups of terminal entries, seems that
171 * aside from bulk I/O such as tic and toe, that leaves interactive programs
172 * which should not be modifying the terminal databases in a way that would
173 * invalidate the search-list.
174 *
175 * The "1-second" is to allow for user-directed changes outside the program.
176 */
177 static bool
cache_expired(void)178 cache_expired(void)
179 {
180 bool result = FALSE;
181 time_t now = time((time_t *) 0);
182
183 if (now > my_time) {
184 result = TRUE;
185 } else {
186 DBDIRS n;
187 for (n = (DBDIRS) 0; n < dbdLAST; ++n) {
188 if (my_vars[n].name != 0
189 && update_getenv(my_vars[n].name, n)) {
190 result = TRUE;
191 break;
192 }
193 }
194 }
195 return result;
196 }
197
198 static void
free_cache(void)199 free_cache(void)
200 {
201 FreeAndNull(my_blob);
202 FreeAndNull(my_list);
203 }
204
205 /*
206 * Record the "official" location of the terminfo directory, according to
207 * the place where we're writing to, or the normal default, if not.
208 */
209 NCURSES_EXPORT(const char *)
_nc_tic_dir(const char * path)210 _nc_tic_dir(const char *path)
211 {
212 T(("_nc_tic_dir %s", NonNull(path)));
213 if (!KeepTicDirectory) {
214 if (path != 0) {
215 TicDirectory = path;
216 HaveTicDirectory = TRUE;
217 } else if (HaveTicDirectory == 0) {
218 if (use_terminfo_vars()) {
219 const char *envp;
220 if ((envp = getenv("TERMINFO")) != 0)
221 return _nc_tic_dir(envp);
222 }
223 }
224 }
225 return TicDirectory ? TicDirectory : TERMINFO;
226 }
227
228 /*
229 * Special fix to prevent the terminfo directory from being moved after tic
230 * has chdir'd to it. If we let it be changed, then if $TERMINFO has a
231 * relative path, we'll lose track of the actual directory.
232 */
233 NCURSES_EXPORT(void)
_nc_keep_tic_dir(const char * path)234 _nc_keep_tic_dir(const char *path)
235 {
236 _nc_tic_dir(path);
237 KeepTicDirectory = TRUE;
238 }
239
240 /*
241 * Cleanup.
242 */
243 NCURSES_EXPORT(void)
_nc_last_db(void)244 _nc_last_db(void)
245 {
246 if (my_blob != 0 && cache_expired()) {
247 free_cache();
248 }
249 }
250
251 /*
252 * This is a simple iterator which allows the caller to step through the
253 * possible locations for a terminfo directory. ncurses uses this to find
254 * terminfo files to read.
255 */
256 NCURSES_EXPORT(const char *)
_nc_next_db(DBDIRS * state,int * offset)257 _nc_next_db(DBDIRS * state, int *offset)
258 {
259 const char *result;
260
261 (void) offset;
262 if ((int) *state < my_size
263 && my_list != 0
264 && my_list[*state] != 0) {
265 result = my_list[*state];
266 (*state)++;
267 } else {
268 result = 0;
269 }
270 if (result != 0) {
271 T(("_nc_next_db %d %s", *state, result));
272 }
273 return result;
274 }
275
276 NCURSES_EXPORT(void)
_nc_first_db(DBDIRS * state,int * offset)277 _nc_first_db(DBDIRS * state, int *offset)
278 {
279 bool cache_has_expired = FALSE;
280 *state = dbdTIC;
281 *offset = 0;
282
283 T((T_CALLED("_nc_first_db")));
284
285 /* build a blob containing all of the strings we will use for a lookup
286 * table.
287 */
288 if (my_blob == 0 || (cache_has_expired = cache_expired())) {
289 size_t blobsize = 0;
290 const char *values[dbdLAST];
291 struct stat *my_stat;
292 int j;
293
294 if (cache_has_expired)
295 free_cache();
296
297 for (j = 0; j < dbdLAST; ++j)
298 values[j] = 0;
299
300 /*
301 * This is the first item in the list, and is used only when tic is
302 * writing to the database, as a performance improvement.
303 */
304 values[dbdTIC] = TicDirectory;
305
306 #if NCURSES_USE_DATABASE
307 #ifdef TERMINFO_DIRS
308 values[dbdCfgList] = TERMINFO_DIRS;
309 #endif
310 #ifdef TERMINFO
311 values[dbdCfgOnce] = TERMINFO;
312 #endif
313 #endif
314
315 #if NCURSES_USE_TERMCAP
316 values[dbdCfgList2] = TERMPATH;
317 #endif
318
319 if (use_terminfo_vars()) {
320 #if NCURSES_USE_DATABASE
321 values[dbdEnvOnce] = cache_getenv("TERMINFO", dbdEnvOnce);
322 values[dbdHome] = _nc_home_terminfo();
323 (void) cache_getenv("HOME", dbdHome);
324 values[dbdEnvList] = cache_getenv("TERMINFO_DIRS", dbdEnvList);
325
326 #endif
327 #if NCURSES_USE_TERMCAP
328 values[dbdEnvOnce2] = cache_getenv("TERMCAP", dbdEnvOnce2);
329 /* only use $TERMCAP if it is an absolute path */
330 if (values[dbdEnvOnce2] != 0
331 && *values[dbdEnvOnce2] != '/') {
332 values[dbdEnvOnce2] = 0;
333 }
334 values[dbdEnvList2] = cache_getenv("TERMPATH", dbdEnvList2);
335 #endif /* NCURSES_USE_TERMCAP */
336 }
337
338 for (j = 0; j < dbdLAST; ++j) {
339 if (values[j] == 0)
340 values[j] = "";
341 blobsize += 2 + strlen(values[j]);
342 }
343
344 my_blob = malloc(blobsize);
345 if (my_blob != 0) {
346 *my_blob = '\0';
347 for (j = 0; j < dbdLAST; ++j) {
348 add_to_blob(values[j], blobsize);
349 }
350
351 /* Now, build an array which will be pointers to the distinct
352 * strings in the blob.
353 */
354 blobsize = 2;
355 for (j = 0; my_blob[j] != '\0'; ++j) {
356 if (my_blob[j] == NCURSES_PATHSEP)
357 ++blobsize;
358 }
359 my_list = typeCalloc(char *, blobsize);
360 my_stat = typeCalloc(struct stat, blobsize);
361 if (my_list != 0 && my_stat != 0) {
362 int k = 0;
363 my_list[k++] = my_blob;
364 for (j = 0; my_blob[j] != '\0'; ++j) {
365 if (my_blob[j] == NCURSES_PATHSEP
366 && ((&my_blob[j] - my_list[k - 1]) != 3
367 || !quick_prefix(my_list[k - 1]))) {
368 my_blob[j] = '\0';
369 my_list[k++] = &my_blob[j + 1];
370 }
371 }
372
373 /*
374 * Eliminate duplicates from the list.
375 */
376 for (j = 0; my_list[j] != 0; ++j) {
377 #ifdef TERMINFO
378 if (*my_list[j] == '\0')
379 my_list[j] = strdup(TERMINFO);
380 #endif
381 trim_formatting(my_list[j]);
382 for (k = 0; k < j; ++k) {
383 if (!strcmp(my_list[j], my_list[k])) {
384 T(("duplicate %s", my_list[j]));
385 k = j - 1;
386 while ((my_list[j] = my_list[j + 1]) != 0) {
387 ++j;
388 }
389 j = k;
390 break;
391 }
392 }
393 }
394
395 /*
396 * Eliminate non-existent databases, and those that happen to
397 * be symlinked to another location.
398 */
399 for (j = 0; my_list[j] != 0; ++j) {
400 bool found = check_existence(my_list[j], &my_stat[j]);
401 #if HAVE_LINK
402 if (found) {
403 for (k = 0; k < j; ++k) {
404 if (my_stat[j].st_dev == my_stat[k].st_dev
405 && my_stat[j].st_ino == my_stat[k].st_ino) {
406 found = FALSE;
407 break;
408 }
409 }
410 }
411 #endif
412 if (!found) {
413 T(("not found %s", my_list[j]));
414 k = j;
415 while ((my_list[k] = my_list[k + 1]) != 0) {
416 ++k;
417 }
418 --j;
419 }
420 }
421 my_size = j;
422 my_time = time((time_t *) 0);
423 } else {
424 FreeAndNull(my_blob);
425 }
426 free(my_stat);
427 }
428 }
429 returnVoid;
430 }
431
432 #if NO_LEAKS
433 void
_nc_db_iterator_leaks(void)434 _nc_db_iterator_leaks(void)
435 {
436 DBDIRS which;
437
438 if (my_blob != 0)
439 FreeAndNull(my_blob);
440 if (my_list != 0)
441 FreeAndNull(my_list);
442 for (which = 0; (int) which < dbdLAST; ++which) {
443 my_vars[which].name = 0;
444 FreeIfNeeded(my_vars[which].value);
445 my_vars[which].value = 0;
446 }
447 }
448 #endif
449