138032Speter/*- 290792Sgshapiro * Copyright (c) 2006,2009,2010 Joseph Koshy 364562Sgshapiro * All rights reserved. 438032Speter * 538032Speter * Redistribution and use in source and binary forms, with or without 638032Speter * modification, are permitted provided that the following conditions 738032Speter * are met: 838032Speter * 1. Redistributions of source code must retain the above copyright 938032Speter * notice, this list of conditions and the following disclaimer. 1038032Speter * 2. Redistributions in binary form must reproduce the above copyright 1138032Speter * notice, this list of conditions and the following disclaimer in the 1238032Speter * documentation and/or other materials provided with the distribution. 1338032Speter * 1464562Sgshapiro * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS `AS IS' AND 1538032Speter * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16110560Sgshapiro * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1790792Sgshapiro * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1838032Speter * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 1938032Speter * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2038032Speter * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2138032Speter * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2238032Speter * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2338032Speter * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2438032Speter * SUCH DAMAGE. 2538032Speter */ 2638032Speter 2738032Speter#include <assert.h> 2838032Speter#include <libelf.h> 2938032Speter#include <stdlib.h> 3038032Speter#include <string.h> 3138032Speter 3238032Speter#include "_libelf.h" 3338032Speter#include "_libelf_ar.h" 3438032Speter 3538032SpeterELFTC_VCSID("$Id: libelf_ar_util.c,v 1.1 2019/02/01 05:27:38 jsg Exp $"); 3638032Speter 3738032Speter/* 3838032Speter * Convert a string bounded by `start' and `start+sz' (exclusive) to a 3938032Speter * number in the specified base. 40110560Sgshapiro */ 41110560Sgshapiroint 42110560Sgshapiro_libelf_ar_get_number(const char *src, size_t sz, unsigned int base, 43110560Sgshapiro size_t *ret) 4438032Speter{ 4538032Speter size_t r; 4638032Speter unsigned int c, v; 4738032Speter const unsigned char *e, *s; 4838032Speter 4938032Speter assert(base <= 10); 5038032Speter 5138032Speter s = (const unsigned char *) src; 5238032Speter e = s + sz; 5338032Speter 5438032Speter /* skip leading blanks */ 5538032Speter for (;s < e && (c = *s) == ' '; s++) 5638032Speter ; 5738032Speter 5838032Speter r = 0L; 5938032Speter for (;s < e; s++) { 6038032Speter if ((c = *s) == ' ') 6138032Speter break; 6238032Speter if (c < '0' || c > '9') 6338032Speter return (0); 6438032Speter v = c - '0'; 6538032Speter if (v >= base) /* Illegal digit. */ 6638032Speter break; 6738032Speter r *= base; 6838032Speter r += v; 6938032Speter } 7038032Speter 7138032Speter *ret = r; 7238032Speter 7338032Speter return (1); 7438032Speter} 7538032Speter 7638032Speter/* 7738032Speter * Return the translated name for an archive member. 7838032Speter */ 7938032Speterchar * 8038032Speter_libelf_ar_get_translated_name(const struct ar_hdr *arh, Elf *ar) 8138032Speter{ 82110560Sgshapiro char *s; 83110560Sgshapiro unsigned char c; 8438032Speter size_t len, offset; 8538032Speter const unsigned char *buf, *p, *q, *r; 8638032Speter const size_t bufsize = sizeof(arh->ar_name); 8738032Speter 8838032Speter assert(arh != NULL); 8938032Speter assert(ar->e_kind == ELF_K_AR); 9038032Speter assert((const unsigned char *) arh >= ar->e_rawfile && 9164562Sgshapiro (const unsigned char *) arh < ar->e_rawfile + ar->e_rawsize); 9238032Speter 9338032Speter buf = (const unsigned char *) arh->ar_name; 9438032Speter 9538032Speter /* 9638032Speter * Check for extended naming. 9738032Speter * 9838032Speter * If the name matches the pattern "^/[0-9]+", it is an 9938032Speter * SVR4-style extended name. If the name matches the pattern 10038032Speter * "#1/[0-9]+", the entry uses BSD style extended naming. 10138032Speter */ 10238032Speter if (buf[0] == '/' && (c = buf[1]) >= '0' && c <= '9') { 10338032Speter /* 10438032Speter * The value in field ar_name is a decimal offset into 10538032Speter * the archive string table where the actual name 10638032Speter * resides. 10738032Speter */ 10838032Speter if (_libelf_ar_get_number((const char *) (buf + 1), 10938032Speter bufsize - 1, 10, &offset) == 0) { 11038032Speter LIBELF_SET_ERROR(ARCHIVE, 0); 11138032Speter return (NULL); 11238032Speter } 11338032Speter 11438032Speter if (offset > ar->e_u.e_ar.e_rawstrtabsz) { 11538032Speter LIBELF_SET_ERROR(ARCHIVE, 0); 11638032Speter return (NULL); 11738032Speter } 11838032Speter 11938032Speter p = q = ar->e_u.e_ar.e_rawstrtab + offset; 12038032Speter r = ar->e_u.e_ar.e_rawstrtab + ar->e_u.e_ar.e_rawstrtabsz; 12138032Speter 12238032Speter for (; p < r && *p != '/'; p++) 12338032Speter ; 12438032Speter len = (size_t) (p - q + 1); /* space for the trailing NUL */ 12538032Speter 12638032Speter if ((s = malloc(len)) == NULL) { 12738032Speter LIBELF_SET_ERROR(RESOURCE, 0); 12838032Speter return (NULL); 12938032Speter } 13038032Speter 13138032Speter (void) strncpy(s, (const char *) q, len - 1); 13238032Speter s[len - 1] = '\0'; 13338032Speter 13438032Speter return (s); 13538032Speter } else if (IS_EXTENDED_BSD_NAME(buf)) { 13638032Speter r = buf + LIBELF_AR_BSD_EXTENDED_NAME_PREFIX_SIZE; 13738032Speter 138110560Sgshapiro if (_libelf_ar_get_number((const char *) r, bufsize - 13938032Speter LIBELF_AR_BSD_EXTENDED_NAME_PREFIX_SIZE, 10, 14090792Sgshapiro &len) == 0) { 14164562Sgshapiro LIBELF_SET_ERROR(ARCHIVE, 0); 14264562Sgshapiro return (NULL); 14364562Sgshapiro } 14464562Sgshapiro 14564562Sgshapiro /* 14664562Sgshapiro * Allocate space for the file name plus a 14764562Sgshapiro * trailing NUL. 14864562Sgshapiro */ 14964562Sgshapiro if ((s = malloc(len + 1)) == NULL) { 15064562Sgshapiro LIBELF_SET_ERROR(RESOURCE, 0); 15164562Sgshapiro return (NULL); 15264562Sgshapiro } 15364562Sgshapiro 15464562Sgshapiro /* 15564562Sgshapiro * The file name follows the archive header. 15690792Sgshapiro */ 15764562Sgshapiro q = (const unsigned char *) (arh + 1); 15864562Sgshapiro 15964562Sgshapiro (void) strncpy(s, (const char *) q, len); 16090792Sgshapiro s[len] = '\0'; 16190792Sgshapiro 16290792Sgshapiro return (s); 16390792Sgshapiro } 16490792Sgshapiro 16590792Sgshapiro /* 16664562Sgshapiro * A 'normal' name. 16764562Sgshapiro * 168 * Skip back over trailing blanks from the end of the field. 169 * In the SVR4 format, a '/' is used as a terminator for 170 * non-special names. 171 */ 172 for (q = buf + bufsize - 1; q >= buf && *q == ' '; --q) 173 ; 174 175 if (q >= buf) { 176 if (*q == '/') { 177 /* 178 * SVR4 style names: ignore the trailing 179 * character '/', but only if the name is not 180 * one of the special names "/" and "//". 181 */ 182 if (q > buf + 1 || 183 (q == (buf + 1) && *buf != '/')) 184 q--; 185 } 186 187 len = (size_t) (q - buf + 2); /* Space for a trailing NUL. */ 188 } else { 189 /* The buffer only had blanks. */ 190 buf = (const unsigned char *) ""; 191 len = 1; 192 } 193 194 if ((s = malloc(len)) == NULL) { 195 LIBELF_SET_ERROR(RESOURCE, 0); 196 return (NULL); 197 } 198 199 (void) strncpy(s, (const char *) buf, len - 1); 200 s[len - 1] = '\0'; 201 202 return (s); 203} 204 205/* 206 * Return the raw name for an archive member, inclusive of any 207 * formatting characters. 208 */ 209char * 210_libelf_ar_get_raw_name(const struct ar_hdr *arh) 211{ 212 char *rawname; 213 const size_t namesz = sizeof(arh->ar_name); 214 215 if ((rawname = malloc(namesz + 1)) == NULL) { 216 LIBELF_SET_ERROR(RESOURCE, 0); 217 return (NULL); 218 } 219 220 (void) strncpy(rawname, arh->ar_name, namesz); 221 rawname[namesz] = '\0'; 222 return (rawname); 223} 224 225/* 226 * Open an 'ar' archive. 227 */ 228Elf * 229_libelf_ar_open(Elf *e, int reporterror) 230{ 231 size_t sz; 232 int scanahead; 233 struct ar_hdr arh; 234 unsigned char *s, *end; 235 236 _libelf_init_elf(e, ELF_K_AR); 237 238 e->e_u.e_ar.e_nchildren = 0; 239 e->e_u.e_ar.e_next = (off_t) -1; 240 241 /* 242 * Look for special members. 243 */ 244 245 s = e->e_rawfile + SARMAG; 246 end = e->e_rawfile + e->e_rawsize; 247 248 assert(e->e_rawsize > 0); 249 250 /* 251 * We use heuristics to determine the flavor of the archive we 252 * are examining. 253 * 254 * SVR4 flavor archives use the name "/ " and "// " for 255 * special members. 256 * 257 * In BSD flavor archives the symbol table, if present, is the 258 * first archive with name "__.SYMDEF". 259 */ 260 261#define READ_AR_HEADER(S, ARH, SZ, END) \ 262 do { \ 263 if ((S) + sizeof((ARH)) > (END)) \ 264 goto error; \ 265 (void) memcpy(&(ARH), (S), sizeof((ARH))); \ 266 if ((ARH).ar_fmag[0] != '`' || (ARH).ar_fmag[1] != '\n') \ 267 goto error; \ 268 if (_libelf_ar_get_number((char *) (ARH).ar_size, \ 269 sizeof((ARH).ar_size), 10, &(SZ)) == 0) \ 270 goto error; \ 271 } while (0) 272 273 READ_AR_HEADER(s, arh, sz, end); 274 275 /* 276 * Handle special archive members for the SVR4 format. 277 */ 278 if (arh.ar_name[0] == '/') { 279 if (sz == 0) 280 goto error; 281 282 e->e_flags |= LIBELF_F_AR_VARIANT_SVR4; 283 284 scanahead = 0; 285 286 /* 287 * The symbol table (file name "/ ") always comes before the 288 * string table (file name "// "). 289 */ 290 if (arh.ar_name[1] == ' ') { 291 /* "/ " => symbol table. */ 292 scanahead = 1; /* The string table to follow. */ 293 294 s += sizeof(arh); 295 e->e_u.e_ar.e_rawsymtab = s; 296 e->e_u.e_ar.e_rawsymtabsz = sz; 297 298 sz = LIBELF_ADJUST_AR_SIZE(sz); 299 s += sz; 300 301 } else if (arh.ar_name[1] == '/' && arh.ar_name[2] == ' ') { 302 /* "// " => string table for long file names. */ 303 s += sizeof(arh); 304 e->e_u.e_ar.e_rawstrtab = s; 305 e->e_u.e_ar.e_rawstrtabsz = sz; 306 307 sz = LIBELF_ADJUST_AR_SIZE(sz); 308 s += sz; 309 } 310 311 /* 312 * If the string table hasn't been seen yet, look for 313 * it in the next member. 314 */ 315 if (scanahead) { 316 READ_AR_HEADER(s, arh, sz, end); 317 318 /* "// " => string table for long file names. */ 319 if (arh.ar_name[0] == '/' && arh.ar_name[1] == '/' && 320 arh.ar_name[2] == ' ') { 321 322 s += sizeof(arh); 323 324 e->e_u.e_ar.e_rawstrtab = s; 325 e->e_u.e_ar.e_rawstrtabsz = sz; 326 327 sz = LIBELF_ADJUST_AR_SIZE(sz); 328 s += sz; 329 } 330 } 331 } else if (strncmp(arh.ar_name, LIBELF_AR_BSD_SYMTAB_NAME, 332 sizeof(LIBELF_AR_BSD_SYMTAB_NAME) - 1) == 0) { 333 /* 334 * BSD style archive symbol table. 335 */ 336 s += sizeof(arh); 337 e->e_u.e_ar.e_rawsymtab = s; 338 e->e_u.e_ar.e_rawsymtabsz = sz; 339 340 sz = LIBELF_ADJUST_AR_SIZE(sz); 341 s += sz; 342 } 343 344 /* 345 * Update the 'next' offset, so that a subsequent elf_begin() 346 * works as expected. 347 */ 348 e->e_u.e_ar.e_next = (off_t) (s - e->e_rawfile); 349 350 return (e); 351 352error: 353 if (!reporterror) { 354 e->e_kind = ELF_K_NONE; 355 return (e); 356 } 357 358 LIBELF_SET_ERROR(ARCHIVE, 0); 359 return (NULL); 360} 361