1/* Handle configuration data.
2 Copyright (C) 1997-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20#include <assert.h>
21#include <ctype.h>
22#include <errno.h>
23#include <limits.h>
24#include <locale.h>
25#include <search.h>
26#include <stddef.h>
27#include <stdio.h>
28#include <stdio_ext.h>
29#include <stdlib.h>
30#include <string.h>
31#include <unistd.h>
32#include <sys/param.h>
33
34#include <libc-lock.h>
35#include <gconv_int.h>
36
37
38/* This is the default path where we look for module lists. */
39static const char default_gconv_path[] = GCONV_PATH;
40
41/* The path elements, as determined by the __gconv_get_path function.
42 All path elements end in a slash. */
43struct path_elem *__gconv_path_elem;
44/* Maximum length of a single path element in __gconv_path_elem. */
45size_t __gconv_max_path_elem_len;
46
47/* We use the following struct if we couldn't allocate memory. */
48static const struct path_elem empty_path_elem = { NULL, 0 };
49
50/* Name of the file containing the module information in the directories
51 along the path. */
52static const char gconv_conf_filename[] = "gconv-modules";
53
54/* Filename extension for the modules. */
55#ifndef MODULE_EXT
56# define MODULE_EXT ".so"
57#endif
58static const char gconv_module_ext[] = MODULE_EXT;
59
60/* We have a few builtin transformations. */
61static struct gconv_module builtin_modules[] =
62{
63#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
64 MinF, MaxF, MinT, MaxT) \
65 { \
66 .from_string = From, \
67 .to_string = To, \
68 .cost_hi = Cost, \
69 .cost_lo = INT_MAX, \
70 .module_name = Name \
71 },
72#define BUILTIN_ALIAS(From, To)
73
74#include "gconv_builtin.h"
75
76#undef BUILTIN_TRANSFORMATION
77#undef BUILTIN_ALIAS
78};
79
80static const char builtin_aliases[] =
81{
82#define BUILTIN_TRANSFORMATION(From, To, Cost, Name, Fct, BtowcFct, \
83 MinF, MaxF, MinT, MaxT)
84#define BUILTIN_ALIAS(From, To) From "\0" To "\0"
85
86#include "gconv_builtin.h"
87
88#undef BUILTIN_TRANSFORMATION
89#undef BUILTIN_ALIAS
90};
91
92#include <libio/libioP.h>
93#define __getdelim(line, len, c, fp) _IO_getdelim (line, len, c, fp)
94
95
96/* Value of the GCONV_PATH environment variable. */
97const char *__gconv_path_envvar;
98
99
100/* Test whether there is already a matching module known. */
101static int
102internal_function
103detect_conflict (const char *alias)
104{
105 struct gconv_module *node = __gconv_modules_db;
106
107 while (node != NULL)
108 {
109 int cmpres = strcmp (alias, node->from_string);
110
111 if (cmpres == 0)
112 /* We have a conflict. */
113 return 1;
114 else if (cmpres < 0)
115 node = node->left;
116 else
117 node = node->right;
118 }
119
120 return node != NULL;
121}
122
123
124/* The actual code to add aliases. */
125static void
126add_alias2 (const char *from, const char *to, const char *wp, void *modules)
127{
128 /* Test whether this alias conflicts with any available module. */
129 if (detect_conflict (from))
130 /* It does conflict, don't add the alias. */
131 return;
132
133 struct gconv_alias *new_alias = (struct gconv_alias *)
134 malloc (sizeof (struct gconv_alias) + (wp - from));
135 if (new_alias != NULL)
136 {
137 void **inserted;
138
139 new_alias->fromname = memcpy ((char *) new_alias
140 + sizeof (struct gconv_alias),
141 from, wp - from);
142 new_alias->toname = new_alias->fromname + (to - from);
143
144 inserted = (void **) __tsearch (new_alias, &__gconv_alias_db,
145 __gconv_alias_compare);
146 if (inserted == NULL || *inserted != new_alias)
147 /* Something went wrong, free this entry. */
148 free (new_alias);
149 }
150}
151
152
153/* Add new alias. */
154static void
155add_alias (char *rp, void *modules)
156{
157 /* We now expect two more string. The strings are normalized
158 (converted to UPPER case) and strored in the alias database. */
159 char *from, *to, *wp;
160
161 while (__isspace_l (*rp, _nl_C_locobj_ptr))
162 ++rp;
163 from = wp = rp;
164 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
165 *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
166 if (*rp == '\0')
167 /* There is no `to' string on the line. Ignore it. */
168 return;
169 *wp++ = '\0';
170 to = ++rp;
171 while (__isspace_l (*rp, _nl_C_locobj_ptr))
172 ++rp;
173 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
174 *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
175 if (to == wp)
176 /* No `to' string, ignore the line. */
177 return;
178 *wp++ = '\0';
179
180 add_alias2 (from, to, wp, modules);
181}
182
183
184/* Insert a data structure for a new module in the search tree. */
185static void
186internal_function
187insert_module (struct gconv_module *newp, int tobefreed)
188{
189 struct gconv_module **rootp = &__gconv_modules_db;
190
191 while (*rootp != NULL)
192 {
193 struct gconv_module *root = *rootp;
194 int cmpres;
195
196 cmpres = strcmp (newp->from_string, root->from_string);
197 if (cmpres == 0)
198 {
199 /* Both strings are identical. Insert the string at the
200 end of the `same' list if it is not already there. */
201 while (strcmp (newp->from_string, root->from_string) != 0
202 || strcmp (newp->to_string, root->to_string) != 0)
203 {
204 rootp = &root->same;
205 root = *rootp;
206 if (root == NULL)
207 break;
208 }
209
210 if (root != NULL)
211 {
212 /* This is a no new conversion. But maybe the cost is
213 better. */
214 if (newp->cost_hi < root->cost_hi
215 || (newp->cost_hi == root->cost_hi
216 && newp->cost_lo < root->cost_lo))
217 {
218 newp->left = root->left;
219 newp->right = root->right;
220 newp->same = root->same;
221 *rootp = newp;
222
223 free (root);
224 }
225 else if (tobefreed)
226 free (newp);
227 return;
228 }
229
230 break;
231 }
232 else if (cmpres < 0)
233 rootp = &root->left;
234 else
235 rootp = &root->right;
236 }
237
238 /* Plug in the new node here. */
239 *rootp = newp;
240}
241
242
243/* Add new module. */
244static void
245internal_function
246add_module (char *rp, const char *directory, size_t dir_len, void **modules,
247 size_t *nmodules, int modcounter)
248{
249 /* We expect now
250 1. `from' name
251 2. `to' name
252 3. filename of the module
253 4. an optional cost value
254 */
255 struct gconv_alias fake_alias;
256 struct gconv_module *new_module;
257 char *from, *to, *module, *wp;
258 int need_ext;
259 int cost_hi;
260
261 while (__isspace_l (*rp, _nl_C_locobj_ptr))
262 ++rp;
263 from = rp;
264 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
265 {
266 *rp = __toupper_l (*rp, _nl_C_locobj_ptr);
267 ++rp;
268 }
269 if (*rp == '\0')
270 return;
271 *rp++ = '\0';
272 to = wp = rp;
273 while (__isspace_l (*rp, _nl_C_locobj_ptr))
274 ++rp;
275 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
276 *wp++ = __toupper_l (*rp++, _nl_C_locobj_ptr);
277 if (*rp == '\0')
278 return;
279 *wp++ = '\0';
280 do
281 ++rp;
282 while (__isspace_l (*rp, _nl_C_locobj_ptr));
283 module = wp;
284 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
285 *wp++ = *rp++;
286 if (*rp == '\0')
287 {
288 /* There is no cost, use one by default. */
289 *wp++ = '\0';
290 cost_hi = 1;
291 }
292 else
293 {
294 /* There might be a cost value. */
295 char *endp;
296
297 *wp++ = '\0';
298 cost_hi = strtol (rp, &endp, 10);
299 if (rp == endp || cost_hi < 1)
300 /* No useful information. */
301 cost_hi = 1;
302 }
303
304 if (module[0] == '\0')
305 /* No module name given. */
306 return;
307 if (module[0] == '/')
308 dir_len = 0;
309
310 /* See whether we must add the ending. */
311 need_ext = 0;
312 if (wp - module < (ptrdiff_t) sizeof (gconv_module_ext)
313 || memcmp (wp - sizeof (gconv_module_ext), gconv_module_ext,
314 sizeof (gconv_module_ext)) != 0)
315 /* We must add the module extension. */
316 need_ext = sizeof (gconv_module_ext) - 1;
317
318 /* See whether we have already an alias with this name defined. */
319 fake_alias.fromname = strndupa (from, to - from);
320
321 if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare) != NULL)
322 /* This module duplicates an alias. */
323 return;
324
325 new_module = (struct gconv_module *) calloc (1,
326 sizeof (struct gconv_module)
327 + (wp - from)
328 + dir_len + need_ext);
329 if (new_module != NULL)
330 {
331 char *tmp;
332
333 new_module->from_string = tmp = (char *) (new_module + 1);
334 tmp = __mempcpy (tmp, from, to - from);
335
336 new_module->to_string = tmp;
337 tmp = __mempcpy (tmp, to, module - to);
338
339 new_module->cost_hi = cost_hi;
340 new_module->cost_lo = modcounter;
341
342 new_module->module_name = tmp;
343
344 if (dir_len != 0)
345 tmp = __mempcpy (tmp, directory, dir_len);
346
347 tmp = __mempcpy (tmp, module, wp - module);
348
349 if (need_ext)
350 memcpy (tmp - 1, gconv_module_ext, sizeof (gconv_module_ext));
351
352 /* Now insert the new module data structure in our search tree. */
353 insert_module (new_module, 1);
354 }
355}
356
357
358/* Read the next configuration file. */
359static void
360internal_function
361read_conf_file (const char *filename, const char *directory, size_t dir_len,
362 void **modules, size_t *nmodules)
363{
364 /* Note the file is opened with cancellation in the I/O functions
365 disabled. */
366 FILE *fp = fopen (filename, "rce");
367 char *line = NULL;
368 size_t line_len = 0;
369 static int modcounter;
370
371 /* Don't complain if a file is not present or readable, simply silently
372 ignore it. */
373 if (fp == NULL)
374 return;
375
376 /* No threads reading from this stream. */
377 __fsetlocking (fp, FSETLOCKING_BYCALLER);
378
379 /* Process the known entries of the file. Comments start with `#' and
380 end with the end of the line. Empty lines are ignored. */
381 while (!feof_unlocked (fp))
382 {
383 char *rp, *endp, *word;
384 ssize_t n = __getdelim (&line, &line_len, '\n', fp);
385 if (n < 0)
386 /* An error occurred. */
387 break;
388
389 rp = line;
390 /* Terminate the line (excluding comments or newline) by an NUL byte
391 to simplify the following code. */
392 endp = strchr (rp, '#');
393 if (endp != NULL)
394 *endp = '\0';
395 else
396 if (rp[n - 1] == '\n')
397 rp[n - 1] = '\0';
398
399 while (__isspace_l (*rp, _nl_C_locobj_ptr))
400 ++rp;
401
402 /* If this is an empty line go on with the next one. */
403 if (rp == endp)
404 continue;
405
406 word = rp;
407 while (*rp != '\0' && !__isspace_l (*rp, _nl_C_locobj_ptr))
408 ++rp;
409
410 if (rp - word == sizeof ("alias") - 1
411 && memcmp (word, "alias", sizeof ("alias") - 1) == 0)
412 add_alias (rp, *modules);
413 else if (rp - word == sizeof ("module") - 1
414 && memcmp (word, "module", sizeof ("module") - 1) == 0)
415 add_module (rp, directory, dir_len, modules, nmodules, modcounter++);
416 /* else */
417 /* Otherwise ignore the line. */
418 }
419
420 free (line);
421
422 fclose (fp);
423}
424
425
426/* Determine the directories we are looking for data in. */
427void
428internal_function
429__gconv_get_path (void)
430{
431 struct path_elem *result;
432 __libc_lock_define_initialized (static, lock);
433
434 __libc_lock_lock (lock);
435
436 /* Make sure there wasn't a second thread doing it already. */
437 result = (struct path_elem *) __gconv_path_elem;
438 if (result == NULL)
439 {
440 /* Determine the complete path first. */
441 char *gconv_path;
442 size_t gconv_path_len;
443 char *elem;
444 char *oldp;
445 char *cp;
446 int nelems;
447 char *cwd;
448 size_t cwdlen;
449
450 if (__gconv_path_envvar == NULL)
451 {
452 /* No user-defined path. Make a modifiable copy of the
453 default path. */
454 gconv_path = strdupa (default_gconv_path);
455 gconv_path_len = sizeof (default_gconv_path);
456 cwd = NULL;
457 cwdlen = 0;
458 }
459 else
460 {
461 /* Append the default path to the user-defined path. */
462 size_t user_len = strlen (__gconv_path_envvar);
463
464 gconv_path_len = user_len + 1 + sizeof (default_gconv_path);
465 gconv_path = alloca (gconv_path_len);
466 __mempcpy (__mempcpy (__mempcpy (gconv_path, __gconv_path_envvar,
467 user_len),
468 ":", 1),
469 default_gconv_path, sizeof (default_gconv_path));
470 cwd = __getcwd (NULL, 0);
471 cwdlen = __glibc_unlikely (cwd == NULL) ? 0 : strlen (cwd);
472 }
473 assert (default_gconv_path[0] == '/');
474
475 /* In a first pass we calculate the number of elements. */
476 oldp = NULL;
477 cp = strchr (gconv_path, ':');
478 nelems = 1;
479 while (cp != NULL)
480 {
481 if (cp != oldp + 1)
482 ++nelems;
483 oldp = cp;
484 cp = strchr (cp + 1, ':');
485 }
486
487 /* Allocate the memory for the result. */
488 result = (struct path_elem *) malloc ((nelems + 1)
489 * sizeof (struct path_elem)
490 + gconv_path_len + nelems
491 + (nelems - 1) * (cwdlen + 1));
492 if (result != NULL)
493 {
494 char *strspace = (char *) &result[nelems + 1];
495 int n = 0;
496
497 /* Separate the individual parts. */
498 __gconv_max_path_elem_len = 0;
499 elem = __strtok_r (gconv_path, ":", &gconv_path);
500 assert (elem != NULL);
501 do
502 {
503 result[n].name = strspace;
504 if (elem[0] != '/')
505 {
506 assert (cwd != NULL);
507 strspace = __mempcpy (strspace, cwd, cwdlen);
508 *strspace++ = '/';
509 }
510 strspace = __stpcpy (strspace, elem);
511 if (strspace[-1] != '/')
512 *strspace++ = '/';
513
514 result[n].len = strspace - result[n].name;
515 if (result[n].len > __gconv_max_path_elem_len)
516 __gconv_max_path_elem_len = result[n].len;
517
518 *strspace++ = '\0';
519 ++n;
520 }
521 while ((elem = __strtok_r (NULL, ":", &gconv_path)) != NULL);
522
523 result[n].name = NULL;
524 result[n].len = 0;
525 }
526
527 __gconv_path_elem = result ?: (struct path_elem *) &empty_path_elem;
528
529 free (cwd);
530 }
531
532 __libc_lock_unlock (lock);
533}
534
535
536/* Read all configuration files found in the user-specified and the default
537 path. */
538void
539attribute_hidden
540__gconv_read_conf (void)
541{
542 void *modules = NULL;
543 size_t nmodules = 0;
544 int save_errno = errno;
545 size_t cnt;
546
547 /* First see whether we should use the cache. */
548 if (__gconv_load_cache () == 0)
549 {
550 /* Yes, we are done. */
551 __set_errno (save_errno);
552 return;
553 }
554
555#ifndef STATIC_GCONV
556 /* Find out where we have to look. */
557 if (__gconv_path_elem == NULL)
558 __gconv_get_path ();
559
560 for (cnt = 0; __gconv_path_elem[cnt].name != NULL; ++cnt)
561 {
562 const char *elem = __gconv_path_elem[cnt].name;
563 size_t elem_len = __gconv_path_elem[cnt].len;
564 char *filename;
565
566 /* No slash needs to be inserted between elem and gconv_conf_filename;
567 elem already ends in a slash. */
568 filename = alloca (elem_len + sizeof (gconv_conf_filename));
569 __mempcpy (__mempcpy (filename, elem, elem_len),
570 gconv_conf_filename, sizeof (gconv_conf_filename));
571
572 /* Read the next configuration file. */
573 read_conf_file (filename, elem, elem_len, &modules, &nmodules);
574 }
575#endif
576
577 /* Add the internal modules. */
578 for (cnt = 0; cnt < sizeof (builtin_modules) / sizeof (builtin_modules[0]);
579 ++cnt)
580 {
581 struct gconv_alias fake_alias;
582
583 fake_alias.fromname = (char *) builtin_modules[cnt].from_string;
584
585 if (__tfind (&fake_alias, &__gconv_alias_db, __gconv_alias_compare)
586 != NULL)
587 /* It'll conflict so don't add it. */
588 continue;
589
590 insert_module (&builtin_modules[cnt], 0);
591 }
592
593 /* Add aliases for builtin conversions. */
594 const char *cp = builtin_aliases;
595 do
596 {
597 const char *from = cp;
598 const char *to = __rawmemchr (from, '\0') + 1;
599 cp = __rawmemchr (to, '\0') + 1;
600
601 add_alias2 (from, to, cp, modules);
602 }
603 while (*cp != '\0');
604
605 /* Restore the error number. */
606 __set_errno (save_errno);
607}
608
609
610
611/* Free all resources if necessary. */
612libc_freeres_fn (free_mem)
613{
614 if (__gconv_path_elem != NULL && __gconv_path_elem != &empty_path_elem)
615 free ((void *) __gconv_path_elem);
616}
617