posix: Add p{read,write}v2 RWF_NOWAIT flag (BZ#21738)
[glibc.git] / locale / loadarchive.c
blobe6e1a05d2e7b74abf81d136760f0c42d58744f57
1 /* Code to load locale data from the locale archive file.
2 Copyright (C) 2002-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 #include <locale.h>
20 #include <stddef.h>
21 #include <stdlib.h>
22 #include <stdbool.h>
23 #include <errno.h>
24 #include <assert.h>
25 #include <string.h>
26 #include <fcntl.h>
27 #include <unistd.h>
28 #include <stdint.h>
29 #include <sys/mman.h>
30 #include <sys/stat.h>
31 #include <sys/param.h>
33 #include "localeinfo.h"
34 #include "locarchive.h"
35 #include <not-cancel.h>
37 /* Define the hash function. We define the function as static inline. */
38 #define compute_hashval static inline compute_hashval
39 #define hashval_t uint32_t
40 #include "hashval.h"
41 #undef compute_hashval
44 /* Name of the locale archive file. */
45 static const char archfname[] = COMPLOCALEDIR "/locale-archive";
47 /* Size of initial mapping window, optimal if large enough to
48 cover the header plus the initial locale. */
49 #define ARCHIVE_MAPPING_WINDOW (2 * 1024 * 1024)
51 #ifndef MAP_COPY
52 /* This is not quite as good as MAP_COPY since unexamined pages
53 can change out from under us and give us inconsistent data.
54 But we rely on the user not to diddle the system's live archive.
55 Even though we only ever use PROT_READ, using MAP_SHARED would
56 not give the system sufficient freedom to e.g. let the on disk
57 file go away because it doesn't know we won't call mprotect later. */
58 # define MAP_COPY MAP_PRIVATE
59 #endif
60 #ifndef MAP_FILE
61 /* Some systems do not have this flag; it is superfluous. */
62 # define MAP_FILE 0
63 #endif
65 /* Record of contiguous pages already mapped from the locale archive. */
66 struct archmapped
68 void *ptr;
69 uint32_t from;
70 uint32_t len;
71 struct archmapped *next;
73 static struct archmapped *archmapped;
75 /* This describes the mapping at the beginning of the file that contains
76 the header data. There could be data in the following partial page,
77 so this is searched like any other. Once the archive has been used,
78 ARCHMAPPED points to this; if mapping the archive header failed,
79 then headmap.ptr is null. */
80 static struct archmapped headmap;
81 static struct stat64 archive_stat; /* stat of archive when header mapped. */
83 /* Record of locales that we have already loaded from the archive. */
84 struct locale_in_archive
86 struct locale_in_archive *next;
87 char *name;
88 struct __locale_data *data[__LC_LAST];
90 static struct locale_in_archive *archloaded;
93 /* Local structure and subroutine of _nl_load_archive, see below. */
94 struct range
96 uint32_t from;
97 uint32_t len;
98 int category;
99 void *result;
102 static int
103 rangecmp (const void *p1, const void *p2)
105 return ((struct range *) p1)->from - ((struct range *) p2)->from;
109 /* Calculate the amount of space needed for all the tables described
110 by the given header. Note we do not include the empty table space
111 that has been preallocated in the file, so our mapping may not be
112 large enough if localedef adds data to the file in place. However,
113 doing that would permute the header fields while we are accessing
114 them and thus not be safe anyway, so we don't allow for that. */
115 static inline off_t
116 calculate_head_size (const struct locarhead *h)
118 off_t namehash_end = (h->namehash_offset
119 + h->namehash_size * sizeof (struct namehashent));
120 off_t string_end = h->string_offset + h->string_used;
121 off_t locrectab_end = (h->locrectab_offset
122 + h->locrectab_used * sizeof (struct locrecent));
123 return MAX (namehash_end, MAX (string_end, locrectab_end));
127 /* Find the locale *NAMEP in the locale archive, and return the
128 internalized data structure for its CATEGORY data. If this locale has
129 already been loaded from the archive, just returns the existing data
130 structure. If successful, sets *NAMEP to point directly into the mapped
131 archive string table; that way, the next call can short-circuit strcmp. */
132 struct __locale_data *
133 internal_function
134 _nl_load_locale_from_archive (int category, const char **namep)
136 const char *name = *namep;
137 struct
139 void *addr;
140 size_t len;
141 } results[__LC_LAST];
142 struct locale_in_archive *lia;
143 struct locarhead *head;
144 struct namehashent *namehashtab;
145 struct locrecent *locrec;
146 struct archmapped *mapped;
147 struct archmapped *last;
148 unsigned long int hval;
149 size_t idx;
150 size_t incr;
151 struct range ranges[__LC_LAST - 1];
152 int nranges;
153 int cnt;
154 size_t ps = __sysconf (_SC_PAGE_SIZE);
155 int fd = -1;
157 /* Check if we have already loaded this locale from the archive.
158 If we previously loaded the locale but found bogons in the data,
159 then we will have stored a null pointer to return here. */
160 for (lia = archloaded; lia != NULL; lia = lia->next)
161 if (name == lia->name || !strcmp (name, lia->name))
163 *namep = lia->name;
164 return lia->data[category];
168 /* If the name contains a codeset, then we normalize the name before
169 doing the lookup. */
170 const char *p = strchr (name, '.');
171 if (p != NULL && p[1] != '@' && p[1] != '\0')
173 const char *rest = __strchrnul (++p, '@');
174 const char *normalized_codeset = _nl_normalize_codeset (p, rest - p);
175 if (normalized_codeset == NULL) /* malloc failure */
176 return NULL;
177 if (strncmp (normalized_codeset, p, rest - p) != 0
178 || normalized_codeset[rest - p] != '\0')
180 /* There is a normalized codeset name that is different from
181 what was specified; reconstruct a new locale name using it. */
182 size_t normlen = strlen (normalized_codeset);
183 size_t restlen = strlen (rest) + 1;
184 char *newname = alloca (p - name + normlen + restlen);
185 memcpy (__mempcpy (__mempcpy (newname, name, p - name),
186 normalized_codeset, normlen),
187 rest, restlen);
188 name = newname;
190 free ((char *) normalized_codeset);
194 /* Make sure the archive is loaded. */
195 if (archmapped == NULL)
197 void *result;
198 size_t headsize, mapsize;
200 /* We do this early as a sign that we have tried to open the archive.
201 If headmap.ptr remains null, that's an indication that we tried
202 and failed, so we won't try again. */
203 archmapped = &headmap;
205 /* The archive has never been opened. */
206 fd = open_not_cancel_2 (archfname, O_RDONLY|O_LARGEFILE|O_CLOEXEC);
207 if (fd < 0)
208 /* Cannot open the archive, for whatever reason. */
209 return NULL;
211 if (__fxstat64 (_STAT_VER, fd, &archive_stat) == -1)
213 /* stat failed, very strange. */
214 close_and_out:
215 if (fd >= 0)
216 close_not_cancel_no_status (fd);
217 return NULL;
221 /* Map an initial window probably large enough to cover the header
222 and the first locale's data. With a large address space, we can
223 just map the whole file and be sure everything is covered. */
225 mapsize = (sizeof (void *) > 4 ? archive_stat.st_size
226 : MIN (archive_stat.st_size, ARCHIVE_MAPPING_WINDOW));
228 result = __mmap64 (NULL, mapsize, PROT_READ, MAP_FILE|MAP_COPY, fd, 0);
229 if (result == MAP_FAILED)
230 goto close_and_out;
232 /* Check whether the file is large enough for the sizes given in
233 the header. Theoretically an archive could be so large that
234 just the header fails to fit in our initial mapping window. */
235 headsize = calculate_head_size ((const struct locarhead *) result);
236 if (headsize > mapsize)
238 (void) __munmap (result, mapsize);
239 if (sizeof (void *) > 4 || headsize > archive_stat.st_size)
240 /* The file is not big enough for the header. Bogus. */
241 goto close_and_out;
243 /* Freakishly long header. */
244 /* XXX could use mremap when available */
245 mapsize = (headsize + ps - 1) & ~(ps - 1);
246 result = __mmap64 (NULL, mapsize, PROT_READ, MAP_FILE|MAP_COPY,
247 fd, 0);
248 if (result == MAP_FAILED)
249 goto close_and_out;
252 if (sizeof (void *) > 4 || mapsize >= archive_stat.st_size)
254 /* We've mapped the whole file already, so we can be
255 sure we won't need this file descriptor later. */
256 close_not_cancel_no_status (fd);
257 fd = -1;
260 headmap.ptr = result;
261 /* headmap.from already initialized to zero. */
262 headmap.len = mapsize;
265 /* If there is no archive or it cannot be loaded for some reason fail. */
266 if (__glibc_unlikely (headmap.ptr == NULL))
267 goto close_and_out;
269 /* We have the archive available. To find the name we first have to
270 determine its hash value. */
271 hval = compute_hashval (name, strlen (name));
273 head = headmap.ptr;
274 namehashtab = (struct namehashent *) ((char *) head
275 + head->namehash_offset);
277 /* Avoid division by 0 if the file is corrupted. */
278 if (__glibc_unlikely (head->namehash_size == 0))
279 goto close_and_out;
281 idx = hval % head->namehash_size;
282 incr = 1 + hval % (head->namehash_size - 2);
284 /* If the name_offset field is zero this means this is a
285 deleted entry and therefore no entry can be found. */
286 while (1)
288 if (namehashtab[idx].name_offset == 0)
289 /* Not found. */
290 goto close_and_out;
292 if (namehashtab[idx].hashval == hval
293 && strcmp (name, headmap.ptr + namehashtab[idx].name_offset) == 0)
294 /* Found the entry. */
295 break;
297 idx += incr;
298 if (idx >= head->namehash_size)
299 idx -= head->namehash_size;
302 /* We found an entry. It might be a placeholder for a removed one. */
303 if (namehashtab[idx].locrec_offset == 0)
304 goto close_and_out;
306 locrec = (struct locrecent *) (headmap.ptr + namehashtab[idx].locrec_offset);
308 if (sizeof (void *) > 4 /* || headmap.len == archive_stat.st_size */)
310 /* We already have the whole locale archive mapped in. */
311 assert (headmap.len == archive_stat.st_size);
312 for (cnt = 0; cnt < __LC_LAST; ++cnt)
313 if (cnt != LC_ALL)
315 if (locrec->record[cnt].offset + locrec->record[cnt].len
316 > headmap.len)
317 /* The archive locrectab contains bogus offsets. */
318 goto close_and_out;
319 results[cnt].addr = headmap.ptr + locrec->record[cnt].offset;
320 results[cnt].len = locrec->record[cnt].len;
323 else
325 /* Get the offsets of the data files and sort them. */
326 for (cnt = nranges = 0; cnt < __LC_LAST; ++cnt)
327 if (cnt != LC_ALL)
329 ranges[nranges].from = locrec->record[cnt].offset;
330 ranges[nranges].len = locrec->record[cnt].len;
331 ranges[nranges].category = cnt;
332 ranges[nranges].result = NULL;
334 ++nranges;
337 qsort (ranges, nranges, sizeof (ranges[0]), rangecmp);
339 /* The information about mmap'd blocks is kept in a list.
340 Skip over the blocks which are before the data we need. */
341 last = mapped = archmapped;
342 for (cnt = 0; cnt < nranges; ++cnt)
344 int upper;
345 size_t from;
346 size_t to;
347 void *addr;
348 struct archmapped *newp;
350 /* Determine whether the appropriate page is already mapped. */
351 while (mapped != NULL
352 && (mapped->from + mapped->len
353 <= ranges[cnt].from + ranges[cnt].len))
355 last = mapped;
356 mapped = mapped->next;
359 /* Do we have a match? */
360 if (mapped != NULL
361 && mapped->from <= ranges[cnt].from
362 && (ranges[cnt].from + ranges[cnt].len
363 <= mapped->from + mapped->len))
365 /* Yep, already loaded. */
366 results[ranges[cnt].category].addr = ((char *) mapped->ptr
367 + ranges[cnt].from
368 - mapped->from);
369 results[ranges[cnt].category].len = ranges[cnt].len;
370 continue;
373 /* Map the range with the locale data from the file. We will
374 try to cover as much of the locale as possible. I.e., if the
375 next category (next as in "next offset") is on the current or
376 immediately following page we use it as well. */
377 assert (powerof2 (ps));
378 from = ranges[cnt].from & ~(ps - 1);
379 upper = cnt;
382 to = ranges[upper].from + ranges[upper].len;
383 if (to > (size_t) archive_stat.st_size)
384 /* The archive locrectab contains bogus offsets. */
385 goto close_and_out;
386 to = (to + ps - 1) & ~(ps - 1);
388 /* If a range is already mmaped in, stop. */
389 if (mapped != NULL && ranges[upper].from >= mapped->from)
390 break;
392 ++upper;
394 /* Loop while still in contiguous pages. */
395 while (upper < nranges && ranges[upper].from < to + ps);
397 /* Open the file if it hasn't happened yet. */
398 if (fd == -1)
400 struct stat64 st;
401 fd = open_not_cancel_2 (archfname,
402 O_RDONLY|O_LARGEFILE|O_CLOEXEC);
403 if (fd == -1)
404 /* Cannot open the archive, for whatever reason. */
405 return NULL;
406 /* Now verify we think this is really the same archive file
407 we opened before. If it has been changed we cannot trust
408 the header we read previously. */
409 if (__fxstat64 (_STAT_VER, fd, &st) < 0
410 || st.st_size != archive_stat.st_size
411 || st.st_mtime != archive_stat.st_mtime
412 || st.st_dev != archive_stat.st_dev
413 || st.st_ino != archive_stat.st_ino)
414 goto close_and_out;
417 /* Map the range from the archive. */
418 addr = __mmap64 (NULL, to - from, PROT_READ, MAP_FILE|MAP_COPY,
419 fd, from);
420 if (addr == MAP_FAILED)
421 goto close_and_out;
423 /* Allocate a record for this mapping. */
424 newp = (struct archmapped *) malloc (sizeof (struct archmapped));
425 if (newp == NULL)
427 (void) __munmap (addr, to - from);
428 goto close_and_out;
431 /* And queue it. */
432 newp->ptr = addr;
433 newp->from = from;
434 newp->len = to - from;
435 assert (last->next == mapped);
436 newp->next = mapped;
437 last->next = newp;
438 last = newp;
440 /* Determine the load addresses for the category data. */
443 assert (ranges[cnt].from >= from);
444 results[ranges[cnt].category].addr = ((char *) addr
445 + ranges[cnt].from - from);
446 results[ranges[cnt].category].len = ranges[cnt].len;
448 while (++cnt < upper);
449 --cnt; /* The 'for' will increase 'cnt' again. */
453 /* We don't need the file descriptor any longer. */
454 if (fd >= 0)
455 close_not_cancel_no_status (fd);
456 fd = -1;
458 /* We succeeded in mapping all the necessary regions of the archive.
459 Now we need the expected data structures to point into the data. */
461 lia = malloc (sizeof *lia);
462 if (__glibc_unlikely (lia == NULL))
463 return NULL;
465 lia->name = __strdup (*namep);
466 if (__glibc_unlikely (lia->name == NULL))
468 free (lia);
469 return NULL;
472 lia->next = archloaded;
473 archloaded = lia;
475 for (cnt = 0; cnt < __LC_LAST; ++cnt)
476 if (cnt != LC_ALL)
478 lia->data[cnt] = _nl_intern_locale_data (cnt,
479 results[cnt].addr,
480 results[cnt].len);
481 if (__glibc_likely (lia->data[cnt] != NULL))
483 /* _nl_intern_locale_data leaves us these fields to initialize. */
484 lia->data[cnt]->alloc = ld_archive;
485 lia->data[cnt]->name = lia->name;
487 /* We do this instead of bumping the count each time we return
488 this data because the mappings stay around forever anyway
489 and we might as well hold on to a little more memory and not
490 have to rebuild it on the next lookup of the same thing.
491 If we were to maintain the usage_count normally and let the
492 structures be freed, we would have to remove the elements
493 from archloaded too. */
494 lia->data[cnt]->usage_count = UNDELETABLE;
498 *namep = lia->name;
499 return lia->data[category];
502 void __libc_freeres_fn_section
503 _nl_archive_subfreeres (void)
505 struct locale_in_archive *lia;
506 struct archmapped *am;
508 /* Toss out our cached locales. */
509 lia = archloaded;
510 while (lia != NULL)
512 int category;
513 struct locale_in_archive *dead = lia;
514 lia = lia->next;
516 free (dead->name);
517 for (category = 0; category < __LC_LAST; ++category)
518 if (category != LC_ALL && dead->data[category] != NULL)
520 /* _nl_unload_locale just does this free for the archive case. */
521 if (dead->data[category]->private.cleanup)
522 (*dead->data[category]->private.cleanup) (dead->data[category]);
524 free (dead->data[category]);
526 free (dead);
528 archloaded = NULL;
530 if (archmapped != NULL)
532 /* Now toss all the mapping windows, which we know nothing is using any
533 more because we just tossed all the locales that point into them. */
535 assert (archmapped == &headmap);
536 archmapped = NULL;
537 (void) __munmap (headmap.ptr, headmap.len);
538 am = headmap.next;
539 while (am != NULL)
541 struct archmapped *dead = am;
542 am = am->next;
543 (void) __munmap (dead->ptr, dead->len);
544 free (dead);