1 /* ELF string table handling.
2 Copyright (C) 2000, 2001, 2002 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 2000.
5
6 Red Hat elfutils is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by the
8 Free Software Foundation; version 2 of the License.
9
10 Red Hat elfutils is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with Red Hat elfutils; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
18
19 In addition, as a special exception, Red Hat, Inc. gives You the
20 additional right to link the code of Red Hat elfutils with code licensed
21 under any Open Source Initiative certified open source license
22 (http://www.opensource.org/licenses/index.php) which requires the
23 distribution of source code with any binary distribution and to
24 distribute linked combinations of the two. Non-GPL Code permitted under
25 this exception must only link to the code of Red Hat elfutils through
26 those well defined interfaces identified in the file named EXCEPTION
27 found in the source code files (the "Approved Interfaces"). The files
28 of Non-GPL Code may instantiate templates or use macros or inline
29 functions from the Approved Interfaces without causing the resulting
30 work to be covered by the GNU General Public License. Only Red Hat,
31 Inc. may make changes or additions to the list of Approved Interfaces.
32 Red Hat's grant of this exception is conditioned upon your not adding
33 any new exceptions. If you wish to add a new Approved Interface or
34 exception, please contact Red Hat. You must obey the GNU General Public
35 License in all respects for all of the Red Hat elfutils code and other
36 code used in conjunction with Red Hat elfutils except the Non-GPL Code
37 covered by this exception. If you modify this file, you may extend this
38 exception to your version of the file, but you are not obligated to do
39 so. If you do not wish to provide this exception without modification,
40 you must delete this exception statement from your version and license
41 this file solely under the GPL without exception.
42
43 Red Hat elfutils is an included package of the Open Invention Network.
44 An included package of the Open Invention Network is a package for which
45 Open Invention Network licensees cross-license their patents. No patent
46 license is granted, either expressly or impliedly, by designation as an
47 included package. Should you wish to participate in the Open Invention
48 Network licensing program, please visit www.openinventionnetwork.com
49 <http://www.openinventionnetwork.com>. */
50
51 #ifdef HAVE_CONFIG_H
52 # include <config.h>
53 #endif
54
55 #include <assert.h>
56 #include <inttypes.h>
57 #include <libelf.h>
58 #include <stddef.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <unistd.h>
62 #include <wchar.h>
63 #include <sys/param.h>
64
65 #include "libebl.h"
66 #include <system.h>
67
68 #ifndef MIN
69 # define MIN(a, b) ((a) < (b) ? (a) : (b))
70 #endif
71
72
73 struct Ebl_WStrent
74 {
75 const wchar_t *string;
76 size_t len;
77 struct Ebl_WStrent *next;
78 struct Ebl_WStrent *left;
79 struct Ebl_WStrent *right;
80 size_t offset;
81 wchar_t reverse[0];
82 };
83
84
85 struct memoryblock
86 {
87 struct memoryblock *next;
88 char memory[0];
89 };
90
91
92 struct Ebl_WStrtab
93 {
94 struct Ebl_WStrent *root;
95 struct memoryblock *memory;
96 char *backp;
97 size_t left;
98 size_t total;
99 bool nullstr;
100
101 struct Ebl_WStrent null;
102 };
103
104
105 /* Cache for the pagesize. We correct this value a bit so that `malloc'
106 is not allocating more than a page. */
107 static size_t ps;
108
109
110 struct Ebl_WStrtab *
ebl_wstrtabinit(bool nullstr)111 ebl_wstrtabinit (bool nullstr)
112 {
113 struct Ebl_WStrtab *ret;
114
115 if (ps == 0)
116 {
117 ps = sysconf (_SC_PAGESIZE) - 2 * sizeof (void *);
118 assert (sizeof (struct memoryblock) < ps);
119 }
120
121 ret = (struct Ebl_WStrtab *) calloc (1, sizeof (struct Ebl_WStrtab));
122 if (ret != NULL)
123 {
124 ret->nullstr = nullstr;
125 if (nullstr)
126 {
127 ret->null.len = 1;
128 ret->null.string = L"";
129 }
130 }
131 return ret;
132 }
133
134
135 static int
morememory(struct Ebl_WStrtab * st,size_t len)136 morememory (struct Ebl_WStrtab *st, size_t len)
137 {
138 struct memoryblock *newmem;
139
140 if (len < ps)
141 len = ps;
142 newmem = (struct memoryblock *) malloc (len);
143 if (newmem == NULL)
144 return 1;
145
146 newmem->next = st->memory;
147 st->memory = newmem;
148 st->backp = newmem->memory;
149 st->left = len - offsetof (struct memoryblock, memory);
150
151 return 0;
152 }
153
154
155 void
ebl_wstrtabfree(struct Ebl_WStrtab * st)156 ebl_wstrtabfree (struct Ebl_WStrtab *st)
157 {
158 struct memoryblock *mb = st->memory;
159
160 while (mb != NULL)
161 {
162 void *old = mb;
163 mb = mb->next;
164 free (old);
165 }
166
167 free (st);
168 }
169
170
171 static struct Ebl_WStrent *
newstring(struct Ebl_WStrtab * st,const wchar_t * str,size_t len)172 newstring (struct Ebl_WStrtab *st, const wchar_t *str, size_t len)
173 {
174 struct Ebl_WStrent *newstr;
175 size_t align;
176 int i;
177
178 /* Compute the amount of padding needed to make the structure aligned. */
179 align = ((__alignof__ (struct Ebl_WStrent)
180 - (((uintptr_t) st->backp)
181 & (__alignof__ (struct Ebl_WStrent) - 1)))
182 & (__alignof__ (struct Ebl_WStrent) - 1));
183
184 /* Make sure there is enough room in the memory block. */
185 if (st->left < align + sizeof (struct Ebl_WStrent) + len * sizeof (wchar_t))
186 {
187 if (morememory (st,
188 sizeof (struct Ebl_WStrent) + len * sizeof (wchar_t)))
189 return NULL;
190
191 align = 0;
192 }
193
194 /* Create the reserved string. */
195 newstr = (struct Ebl_WStrent *) (st->backp + align);
196 newstr->string = str;
197 newstr->len = len;
198 newstr->next = NULL;
199 newstr->left = NULL;
200 newstr->right = NULL;
201 newstr->offset = 0;
202 for (i = len - 2; i >= 0; --i)
203 newstr->reverse[i] = str[len - 2 - i];
204 newstr->reverse[len - 1] = L'\0';
205 st->backp += align + sizeof (struct Ebl_WStrent) + len * sizeof (wchar_t);
206 st->left -= align + sizeof (struct Ebl_WStrent) + len * sizeof (wchar_t);
207
208 return newstr;
209 }
210
211
212 /* XXX This function should definitely be rewritten to use a balancing
213 tree algorith (AVL, red-black trees). For now a simple, correct
214 implementation is enough. */
215 static struct Ebl_WStrent **
searchstring(struct Ebl_WStrent ** sep,struct Ebl_WStrent * newstr)216 searchstring (struct Ebl_WStrent **sep, struct Ebl_WStrent *newstr)
217 {
218 int cmpres;
219
220 /* More strings? */
221 if (*sep == NULL)
222 {
223 *sep = newstr;
224 return sep;
225 }
226
227 /* Compare the strings. */
228 cmpres = wmemcmp ((*sep)->reverse, newstr->reverse,
229 MIN ((*sep)->len, newstr->len) - 1);
230 if (cmpres == 0)
231 /* We found a matching string. */
232 return sep;
233 else if (cmpres > 0)
234 return searchstring (&(*sep)->left, newstr);
235 else
236 return searchstring (&(*sep)->right, newstr);
237 }
238
239
240 /* Add new string. The actual string is assumed to be permanent. */
241 struct Ebl_WStrent *
ebl_wstrtabadd(struct Ebl_WStrtab * st,const wchar_t * str,size_t len)242 ebl_wstrtabadd (struct Ebl_WStrtab *st, const wchar_t *str, size_t len)
243 {
244 struct Ebl_WStrent *newstr;
245 struct Ebl_WStrent **sep;
246
247 /* Compute the string length if the caller doesn't know it. */
248 if (len == 0)
249 len = wcslen (str) + 1;
250
251 /* Make sure all "" strings get offset 0 but only if the table was
252 created with a special null entry in mind. */
253 if (len == 1 && st->null.string != NULL)
254 return &st->null;
255
256 /* Allocate memory for the new string and its associated information. */
257 newstr = newstring (st, str, len);
258 if (newstr == NULL)
259 return NULL;
260
261 /* Search in the array for the place to insert the string. If there
262 is no string with matching prefix and no string with matching
263 leading substring, create a new entry. */
264 sep = searchstring (&st->root, newstr);
265 if (*sep != newstr)
266 {
267 /* This is not the same entry. This means we have a prefix match. */
268 if ((*sep)->len > newstr->len)
269 {
270 struct Ebl_WStrent *subs;
271
272 /* Check whether we already know this string. */
273 for (subs = (*sep)->next; subs != NULL; subs = subs->next)
274 if (subs->len == newstr->len)
275 {
276 /* We have an exact match with a substring. Free the memory
277 we allocated. */
278 st->left += st->backp - (char *) newstr;
279 st->backp = (char *) newstr;
280
281 return subs;
282 }
283
284 /* We have a new substring. This means we don't need the reverse
285 string of this entry anymore. */
286 st->backp -= newstr->len;
287 st->left += newstr->len;
288
289 newstr->next = (*sep)->next;
290 (*sep)->next = newstr;
291 }
292 else if ((*sep)->len != newstr->len)
293 {
294 /* When we get here it means that the string we are about to
295 add has a common prefix with a string we already have but
296 it is longer. In this case we have to put it first. */
297 st->total += newstr->len - (*sep)->len;
298 newstr->next = *sep;
299 newstr->left = (*sep)->left;
300 newstr->right = (*sep)->right;
301 *sep = newstr;
302 }
303 else
304 {
305 /* We have an exact match. Free the memory we allocated. */
306 st->left += st->backp - (char *) newstr;
307 st->backp = (char *) newstr;
308
309 newstr = *sep;
310 }
311 }
312 else
313 st->total += newstr->len;
314
315 return newstr;
316 }
317
318
319 static void
copystrings(struct Ebl_WStrent * nodep,wchar_t ** freep,size_t * offsetp)320 copystrings (struct Ebl_WStrent *nodep, wchar_t **freep, size_t *offsetp)
321 {
322 struct Ebl_WStrent *subs;
323
324 if (nodep->left != NULL)
325 copystrings (nodep->left, freep, offsetp);
326
327 /* Process the current node. */
328 nodep->offset = *offsetp;
329 *freep = wmempcpy (*freep, nodep->string, nodep->len);
330 *offsetp += nodep->len * sizeof (wchar_t);
331
332 for (subs = nodep->next; subs != NULL; subs = subs->next)
333 {
334 assert (subs->len < nodep->len);
335 subs->offset = nodep->offset + nodep->len - subs->len;
336 assert (subs->offset != 0 || subs->string[0] == '\0');
337 }
338
339 if (nodep->right != NULL)
340 copystrings (nodep->right, freep, offsetp);
341 }
342
343
344 void
ebl_wstrtabfinalize(struct Ebl_WStrtab * st,Elf_Data * data)345 ebl_wstrtabfinalize (struct Ebl_WStrtab *st, Elf_Data *data)
346 {
347 size_t copylen;
348 wchar_t *endp;
349 size_t nulllen = st->nullstr ? 1 : 0;
350
351 /* Fill in the information. */
352 data->d_buf = malloc ((st->total + nulllen) * sizeof (wchar_t));
353 if (data->d_buf == NULL)
354 abort ();
355
356 /* The first byte must always be zero if we created the table with a
357 null string. */
358 if (st->nullstr)
359 *((wchar_t *) data->d_buf) = L'\0';
360
361 data->d_type = ELF_T_BYTE;
362 data->d_size = st->total + nulllen;
363 data->d_off = 0;
364 data->d_align = 1;
365 data->d_version = EV_CURRENT;
366
367 /* Now run through the tree and add all the string while also updating
368 the offset members of the elfstrent records. */
369 endp = (wchar_t *) data->d_buf + nulllen;
370 copylen = sizeof (wchar_t) * nulllen;
371 copystrings (st->root, &endp, ©len);
372 assert (copylen == (st->total + nulllen) * sizeof (wchar_t));
373 }
374
375
376 size_t
ebl_wstrtaboffset(struct Ebl_WStrent * se)377 ebl_wstrtaboffset (struct Ebl_WStrent *se)
378 {
379 return se->offset;
380 }
381