1 /* Generic string table handling. 2 Copyright (C) 2000, 2001, 2002, 2005 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper (at) 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 <sys/param.h> 63 64 #include "libebl.h" 65 66 #ifndef MIN 67 # define MIN(a, b) ((a) < (b) ? (a) : (b)) 68 #endif 69 70 71 struct Ebl_GStrent 72 { 73 const char *string; 74 size_t len; 75 struct Ebl_GStrent *next; 76 struct Ebl_GStrent *left; 77 struct Ebl_GStrent *right; 78 size_t offset; 79 unsigned int width; 80 char reverse[0]; 81 }; 82 83 84 struct memoryblock 85 { 86 struct memoryblock *next; 87 char memory[0]; 88 }; 89 90 91 struct Ebl_GStrtab 92 { 93 struct Ebl_GStrent *root; 94 struct memoryblock *memory; 95 char *backp; 96 size_t left; 97 size_t total; 98 unsigned int width; 99 bool nullstr; 100 101 struct Ebl_GStrent 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_GStrtab * 111 ebl_gstrtabinit (unsigned int width, bool nullstr) 112 { 113 struct Ebl_GStrtab *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_GStrtab *) calloc (1, sizeof (struct Ebl_GStrtab)); 122 if (ret != NULL) 123 { 124 ret->width = width; 125 ret->nullstr = nullstr; 126 127 if (nullstr) 128 { 129 ret->null.len = 1; 130 ret->null.string = (char *) calloc (1, width); 131 } 132 } 133 134 return ret; 135 } 136 137 138 static void 139 morememory (struct Ebl_GStrtab *st, size_t len) 140 { 141 struct memoryblock *newmem; 142 143 if (len < ps) 144 len = ps; 145 newmem = (struct memoryblock *) malloc (len); 146 if (newmem == NULL) 147 abort (); 148 149 newmem->next = st->memory; 150 st->memory = newmem; 151 st->backp = newmem->memory; 152 st->left = len - offsetof (struct memoryblock, memory); 153 } 154 155 156 void 157 ebl_gstrtabfree (struct Ebl_GStrtab *st) 158 { 159 struct memoryblock *mb = st->memory; 160 161 while (mb != NULL) 162 { 163 void *old = mb; 164 mb = mb->next; 165 free (old); 166 } 167 168 if (st->null.string != NULL) 169 free ((char *) st->null.string); 170 171 free (st); 172 } 173 174 175 static struct Ebl_GStrent * 176 newstring (struct Ebl_GStrtab *st, const char *str, size_t len) 177 { 178 /* Compute the amount of padding needed to make the structure aligned. */ 179 size_t align = ((__alignof__ (struct Ebl_GStrent) 180 - (((uintptr_t) st->backp) 181 & (__alignof__ (struct Ebl_GStrent) - 1))) 182 & (__alignof__ (struct Ebl_GStrent) - 1)); 183 184 /* Make sure there is enough room in the memory block. */ 185 if (st->left < align + sizeof (struct Ebl_GStrent) + len * st->width) 186 { 187 morememory (st, sizeof (struct Ebl_GStrent) + len * st->width); 188 align = 0; 189 } 190 191 /* Create the reserved string. */ 192 struct Ebl_GStrent *newstr = (struct Ebl_GStrent *) (st->backp + align); 193 newstr->string = str; 194 newstr->len = len; 195 newstr->width = st->width; 196 newstr->next = NULL; 197 newstr->left = NULL; 198 newstr->right = NULL; 199 newstr->offset = 0; 200 for (int i = len - 2; i >= 0; --i) 201 for (int j = st->width - 1; j >= 0; --j) 202 newstr->reverse[i * st->width + j] = str[(len - 2 - i) * st->width + j]; 203 for (size_t j = 0; j < st->width; ++j) 204 newstr->reverse[(len - 1) * st->width + j] = '\0'; 205 st->backp += align + sizeof (struct Ebl_GStrent) + len * st->width; 206 st->left -= align + sizeof (struct Ebl_GStrent) + len * st->width; 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_GStrent ** 216 searchstring (struct Ebl_GStrent **sep, struct Ebl_GStrent *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 = memcmp ((*sep)->reverse, newstr->reverse, 229 (MIN ((*sep)->len, newstr->len) - 1) * (*sep)->width); 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_GStrent * 242 ebl_gstrtabadd (struct Ebl_GStrtab *st, const char *str, size_t len) 243 { 244 struct Ebl_GStrent *newstr; 245 struct Ebl_GStrent **sep; 246 247 /* Compute the string length if the caller doesn't know it. */ 248 if (len == 0) 249 { 250 size_t j; 251 252 do 253 for (j = 0; j < st->width; ++j) 254 if (str[len * st->width + j] != '\0') 255 break; 256 while (j == st->width && ++len); 257 } 258 259 /* Make sure all "" strings get offset 0 but only if the table was 260 created with a special null entry in mind. */ 261 if (len == 1 && st->null.string != NULL) 262 return &st->null; 263 264 /* Allocate memory for the new string and its associated information. */ 265 newstr = newstring (st, str, len); 266 267 /* Search in the array for the place to insert the string. If there 268 is no string with matching prefix and no string with matching 269 leading substring, create a new entry. */ 270 sep = searchstring (&st->root, newstr); 271 if (*sep != newstr) 272 { 273 /* This is not the same entry. This means we have a prefix match. */ 274 if ((*sep)->len > newstr->len) 275 { 276 struct Ebl_GStrent *subs; 277 278 /* Check whether we already know this string. */ 279 for (subs = (*sep)->next; subs != NULL; subs = subs->next) 280 if (subs->len == newstr->len) 281 { 282 /* We have an exact match with a substring. Free the memory 283 we allocated. */ 284 st->left += (st->backp - (char *) newstr) * st->width; 285 st->backp = (char *) newstr; 286 287 return subs; 288 } 289 290 /* We have a new substring. This means we don't need the reverse 291 string of this entry anymore. */ 292 st->backp -= newstr->len; 293 st->left += newstr->len; 294 295 newstr->next = (*sep)->next; 296 (*sep)->next = newstr; 297 } 298 else if ((*sep)->len != newstr->len) 299 { 300 /* When we get here it means that the string we are about to 301 add has a common prefix with a string we already have but 302 it is longer. In this case we have to put it first. */ 303 st->total += newstr->len - (*sep)->len; 304 newstr->next = *sep; 305 newstr->left = (*sep)->left; 306 newstr->right = (*sep)->right; 307 *sep = newstr; 308 } 309 else 310 { 311 /* We have an exact match. Free the memory we allocated. */ 312 st->left += (st->backp - (char *) newstr) * st->width; 313 st->backp = (char *) newstr; 314 315 newstr = *sep; 316 } 317 } 318 else 319 st->total += newstr->len; 320 321 return newstr; 322 } 323 324 325 static void 326 copystrings (struct Ebl_GStrent *nodep, char **freep, size_t *offsetp) 327 { 328 struct Ebl_GStrent *subs; 329 330 if (nodep->left != NULL) 331 copystrings (nodep->left, freep, offsetp); 332 333 /* Process the current node. */ 334 nodep->offset = *offsetp; 335 *freep = (char *) mempcpy (*freep, nodep->string, nodep->len * nodep->width); 336 *offsetp += nodep->len * nodep->width; 337 338 for (subs = nodep->next; subs != NULL; subs = subs->next) 339 { 340 assert (subs->len < nodep->len); 341 subs->offset = nodep->offset + (nodep->len - subs->len) * nodep->width; 342 assert (subs->offset != 0 || subs->string[0] == '\0'); 343 } 344 345 if (nodep->right != NULL) 346 copystrings (nodep->right, freep, offsetp); 347 } 348 349 350 void 351 ebl_gstrtabfinalize (struct Ebl_GStrtab *st, Elf_Data *data) 352 { 353 size_t copylen; 354 char *endp; 355 size_t nulllen = st->nullstr ? st->width : 0; 356 357 /* Fill in the information. */ 358 data->d_buf = malloc (st->total + nulllen); 359 if (data->d_buf == NULL) 360 abort (); 361 362 /* The first byte must always be zero if we created the table with a 363 null string. */ 364 if (st->nullstr) 365 memset (data->d_buf, '\0', st->width); 366 367 data->d_type = ELF_T_BYTE; 368 data->d_size = st->total + nulllen; 369 data->d_off = 0; 370 data->d_align = 1; 371 data->d_version = EV_CURRENT; 372 373 /* Now run through the tree and add all the string while also updating 374 the offset members of the elfstrent records. */ 375 endp = (char *) data->d_buf + nulllen; 376 copylen = nulllen; 377 copystrings (st->root, &endp, ©len); 378 assert (copylen == st->total * st->width + nulllen); 379 } 380 381 382 size_t 383 ebl_gstrtaboffset (struct Ebl_GStrent *se) 384 { 385 return se->offset; 386 } 387
