1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* 23 * Copyright 2004 Sun Microsystems, Inc. All rights reserved. 24 * Use is subject to license terms. 25 */ 26 #pragma ident "%Z%%M% %I% %E% SMI" 27 28 29 #include <stdio.h> 30 #include <stdlib.h> 31 #include <unistd.h> 32 #include <stdarg.h> 33 #include <string.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <libintl.h> 37 #include <locale.h> 38 #include <fcntl.h> 39 #include <dlfcn.h> 40 #include "conv.h" 41 #include "libld.h" 42 #include "msg.h" 43 44 45 /* 46 * The following prevent us from having to include ctype.h which defines these 47 * functions as macros which reference the __ctype[] array. Go through .plt's 48 * to get to these functions in libc rather than have every invocation of ld 49 * have to suffer the R_SPARC_COPY overhead of the __ctype[] array. 50 */ 51 extern int isspace(int); 52 53 54 /* 55 * Determine whether we need the Elf32 or Elf64 libld. 56 */ 57 static int 58 determine_class(int argc, char ** argv) 59 { 60 unsigned char class = 0; 61 int c; 62 63 getmore: 64 /* 65 * Skip options. 66 * 67 * The only option we're interested in is -64, which enforces a 64-bit 68 * link-edit. This option is used when the only input to ld() is a 69 * mapfile and a 64-bit object is required. If we've already processed 70 * a 32-bit object and we find -64, we have an error condition, but let 71 * this fall through to libld to obtain the default error message. 72 */ 73 opterr = 0; 74 while ((c = getopt(argc, argv, MSG_ORIG(MSG_STR_OPTIONS))) != -1) { 75 switch (c) { 76 case '6': 77 return (ELFCLASS64); 78 default: 79 break; 80 } 81 } 82 83 /* 84 * Otherwise look for the first ELF object to determine the class of 85 * objects to operate on. 86 */ 87 for (; optind < argc; optind++) { 88 int fd; 89 unsigned char ident[EI_NIDENT]; 90 91 /* 92 * If we've already analyzed the initial object, continue. 93 * We're only interested in skipping all files to check for 94 * more options, and specifically if the -64 option is set. 95 */ 96 if (class) 97 continue; 98 99 /* 100 * If we detect some more options return to getopt(). 101 * Checking argv[optind][1] against null prevents a forever 102 * loop if an unadorned `-' argument is passed to us. 103 */ 104 if (argv[optind][0] == '-') { 105 if (argv[optind][1] == '\0') 106 continue; 107 else 108 goto getmore; 109 } 110 111 if ((fd = open(argv[optind], O_RDONLY)) == -1) { 112 int err = errno; 113 114 eprintf(ERR_FATAL, MSG_INTL(MSG_SYS_OPEN), 115 argv[optind], strerror(err)); 116 return (0); 117 } 118 119 /* 120 * Determine the files ELF class. 121 */ 122 if ((read(fd, ident, EI_NIDENT) == EI_NIDENT) && 123 (ident[EI_MAG0] == ELFMAG0) && 124 (ident[EI_MAG1] == ELFMAG1) && 125 (ident[EI_MAG2] == ELFMAG2) && 126 (ident[EI_MAG3] == ELFMAG3)) { 127 if (((class = ident[EI_CLASS]) != ELFCLASS32) && 128 (class != ELFCLASS64)) 129 class = 0; 130 } 131 (void) close(fd); 132 } 133 134 /* 135 * If we couldn't establish a class default to 32-bit. 136 */ 137 if (class) 138 return (class); 139 140 return (ELFCLASS32); 141 } 142 143 /* 144 * Prepend environment string as a series of options to the argv array. 145 */ 146 static int 147 prepend_ldoptions(char *ld_options, int *argcp, char ***argvp) 148 { 149 int nargc; /* New argc */ 150 char **nargv; /* New argv */ 151 char *arg, *string; 152 int count; 153 154 /* 155 * Get rid of leading white space, and make sure the string has size. 156 */ 157 while (isspace(*ld_options)) 158 ld_options++; 159 if (*ld_options == '\0') 160 return (1); 161 162 nargc = 0; 163 arg = string = ld_options; 164 165 /* 166 * Walk the environment string counting any arguments that are 167 * separated by white space. 168 */ 169 while (*string != '\0') { 170 if (isspace(*string)) { 171 nargc++; 172 while (isspace(*string)) 173 string++; 174 arg = string; 175 } else 176 string++; 177 } 178 if (arg != string) 179 nargc++; 180 181 /* 182 * Allocate a new argv array big enough to hold the new options from 183 * the environment string and the old argv options. 184 */ 185 if ((nargv = calloc(nargc + *argcp, sizeof (char *))) == 0) 186 return (0); 187 188 /* 189 * Initialize first element of new argv array to be the first element 190 * of the old argv array (ie. calling programs name). Then add the new 191 * args obtained from the environment. 192 */ 193 nargv[0] = (*argvp)[0]; 194 nargc = 0; 195 arg = string = ld_options; 196 while (*string != '\0') { 197 if (isspace(*string)) { 198 nargc++; 199 *string++ = '\0'; 200 nargv[nargc] = arg; 201 while (isspace(*string)) 202 string++; 203 arg = string; 204 } else 205 string++; 206 } 207 if (arg != string) { 208 nargc++; 209 nargv[nargc] = arg; 210 } 211 212 /* 213 * Now add the original argv array (skipping argv[0]) to the end of the 214 * new argv array, and overwrite the old argc and argv. 215 */ 216 for (count = 1; count < *argcp; count++) { 217 nargc++; 218 nargv[nargc] = (*argvp)[count]; 219 } 220 *argcp = ++nargc; 221 *argvp = nargv; 222 223 return (1); 224 } 225 226 /* 227 * The ld_altexec() function checks to see if there is 228 * a LD_ALTEXEC=<path to alternate ld> in the environment. 229 * If there is - it will null that variable out - and then 230 * exec() the binary pointed to with the same arguements 231 * as the originating process. 232 * This permits using alternate link-editors (debugging/developer 233 * copies) even in complex build environments. 234 * 235 * If LD_ALTEXEC= isn't set, or the exec() fails this 236 * function silently returns and the execution of this 237 * link-editor continues on. 238 */ 239 void 240 ld_altexec(char **argv, char **envp) 241 { 242 char *execstr; 243 char **str; 244 for (str = envp; *str; str++) { 245 if (strncmp(*str, MSG_ORIG(MSG_LD_ALTEXEC), 246 MSG_LD_ALTEXEC_SIZE) == 0) { 247 break; 248 } 249 } 250 if (*str == 0) 251 return; 252 253 /* 254 * get a pointer to the actual string - if it's 255 * a null entry - we return. 256 */ 257 execstr = strdup(*str + MSG_LD_ALTEXEC_SIZE); 258 if (*execstr == '\0') 259 return; 260 /* 261 * Null out the LD_ALTEXEC= environment entry. 262 */ 263 (*str)[MSG_LD_ALTEXEC_SIZE] = '\0'; 264 265 /* 266 * Set argv[0] to point to our new linker 267 */ 268 argv[0] = execstr; 269 270 /* 271 * And attempt to execute it. 272 */ 273 (void) execve(execstr, argv, envp); 274 275 /* 276 * If the exec failes - we just silently fall 277 * through and continue execution of the 278 * current link-editor. 279 */ 280 } 281 282 int 283 main(int argc, char **argv, char **envp) 284 { 285 char *ld_options, **oargv = argv; 286 const char *libld = MSG_ORIG(MSG_LD_LIB32); 287 void *libld_h; 288 int (*libld_main)(int, char **); 289 unsigned char class; 290 291 /* 292 * XX64 -- Strip "-Wl," from the head of each argument. 293 * This is to accommodate awkwardness in pasing ld arguments 294 * to gcc while maintaining the structure of the build 295 * environment's Makefiles. 296 */ 297 { 298 int i; 299 char *p; 300 301 for (i = 0; i < argc; i++) { 302 p = argv[i]; 303 while (*(p + 1) == 'W' && strncmp(p, "-Wl,-", 5) == 0) 304 argv[i] = (p += 4); 305 } 306 } 307 308 /* 309 * Establish locale. 310 */ 311 (void) setlocale(LC_MESSAGES, MSG_ORIG(MSG_STR_EMPTY)); 312 (void) textdomain(MSG_ORIG(MSG_SUNW_OST_SGS)); 313 314 /* 315 * Execute alternate linker if LD_ALTEXEC environment variable is set. 316 */ 317 ld_altexec(argv, envp); 318 319 /* 320 * Check the LD_OPTIONS environment variable, and if present prepend 321 * the arguments specified to the command line argument list. 322 */ 323 if ((ld_options = getenv(MSG_ORIG(MSG_LD_OPTIONS))) != NULL) { 324 /* 325 * Prevent modification of actual environment strings. 326 */ 327 if (((ld_options = strdup(ld_options)) == NULL) || 328 (prepend_ldoptions(ld_options, &argc, &argv) == 0)) 329 return (1); 330 } 331 332 /* 333 * Locate the first input file and from it determine the class of 334 * objects we're going to process. If the class is ELFCLASS64 we'll 335 * specifically load libld.so.3, otherwise we'll fall back to 336 * libld.so.2. Note that if the option -64 is encountered a 64-bit 337 * link is explicitly being requested. 338 */ 339 if ((class = determine_class(argc, argv)) == 0) 340 return (1); 341 342 /* 343 * dlopen() right libld implementation. Note: the RTLD_GLOBAL flag is 344 * added to make ld behave as if libld was one of its dependencies. 345 * Support libraries, like libldstab.so.1, may expect this, to get at 346 * libld_malloc, which they argueably shouldn't be using anyway. 347 */ 348 if (class == ELFCLASS64) { 349 /* 350 * If we're on a 64-bit kernel, try to exec a full 64-bit 351 * version of ld. 352 */ 353 conv_check_native(oargv, envp); 354 libld = MSG_ORIG(MSG_LD_LIB64); 355 } 356 if ((libld_h = dlopen(libld, (RTLD_LAZY | RTLD_GLOBAL))) == NULL) { 357 eprintf(ERR_FATAL, MSG_INTL(MSG_SYS_DLOPEN), libld, dlerror()); 358 return (1); 359 } 360 361 /* 362 * Find ld_main(), which is ld's generic entry point. 363 */ 364 if ((libld_main = (int (*)(int, char **))dlsym(libld_h, 365 MSG_ORIG(MSG_LD_MAIN))) == NULL) { 366 eprintf(ERR_FATAL, MSG_INTL(MSG_SYS_DLSYM), libld, dlerror()); 367 return (1); 368 } 369 370 /* 371 * Reset the arg counter and getopt(3c) error message flag and call the 372 * generic entry point. 373 */ 374 optind = opterr = 1; 375 return (libld_main(argc, argv)); 376 } 377 378 379 /* 380 * Exported interfaces required by our dependencies. libld and friends bind to 381 * the different implementations of these provided by either ld or ld.so.1. 382 */ 383 const char * 384 _ld_msg(Msg mid) 385 { 386 return (gettext(MSG_ORIG(mid))); 387 } 388 389 /* 390 * Print a message to stdout 391 */ 392 /* VARARGS2 */ 393 void 394 eprintf(Error error, const char *format, ...) 395 { 396 va_list args; 397 static const char *strings[ERR_NUM] = { MSG_ORIG(MSG_STR_EMPTY) }; 398 399 if (error > ERR_NONE) { 400 if (error == ERR_WARNING) { 401 if (strings[ERR_WARNING] == 0) 402 strings[ERR_WARNING] = MSG_INTL(MSG_ERR_WARNING); 403 } else if (error == ERR_FATAL) { 404 if (strings[ERR_FATAL] == 0) 405 strings[ERR_FATAL] = MSG_INTL(MSG_ERR_FATAL); 406 } else if (error == ERR_ELF) { 407 if (strings[ERR_ELF] == 0) 408 strings[ERR_ELF] = MSG_INTL(MSG_ERR_ELF); 409 } 410 (void) fputs(MSG_ORIG(MSG_STR_LDDIAG), stderr); 411 } 412 (void) fputs(strings[error], stderr); 413 414 va_start(args, format); 415 (void) vfprintf(stderr, format, args); 416 if (error == ERR_ELF) { 417 int elferr; 418 419 if ((elferr = elf_errno()) != 0) 420 (void) fprintf(stderr, MSG_ORIG(MSG_STR_ELFDIAG), 421 elf_errmsg(elferr)); 422 } 423 (void) fprintf(stderr, MSG_ORIG(MSG_STR_NL)); 424 (void) fflush(stderr); 425 va_end(args); 426 } 427