toolchain/toolchain-wrapper.c

   1 /**
   2  * Buildroot wrapper for toolchains. This simply executes the real toolchain
   3  * with a number of arguments (sysroot/arch/..) hardcoded, to ensure the
   4  * toolchain uses the correct configuration.
   5  * The hardcoded path arguments are defined relative to the actual location
   6  * of the binary.
   7  *
   8  * (C) 2011 Peter Korsgaard <jacmet@sunsite.dk>
   9  * (C) 2011 Daniel Nyström <daniel.nystrom@timeterminal.se>
  10  * (C) 2012 Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
  11  * (C) 2013 Spenser Gilliland <spenser@gillilanding.com>
  12  *
  13  * This file is licensed under the terms of the GNU General Public License
  14  * version 2.  This program is licensed "as is" without any warranty of any
  15  * kind, whether express or implied.
  16  */
  17
  18 #define _GNU_SOURCE
  19 #include <stdio.h>
  20 #include <string.h>
  21 #include <limits.h>
  22 #include <unistd.h>
  23 #include <stdlib.h>
  24 #include <errno.h>
  25
  26 #ifdef BR_CCACHE
  27 static char ccache_path[PATH_MAX];
  28 #endif
  29 static char path[PATH_MAX];
  30 static char sysroot[PATH_MAX];
  31
  32 /**
  33  * GCC errors out with certain combinations of arguments (examples are
  34  * -mfloat-abi={hard|soft} and -m{little|big}-endian), so we have to ensure
  35  * that we only pass the predefined one to the real compiler if the inverse
  36  * option isn't in the argument list.
  37  * This specifies the worst case number of extra arguments we might pass
  38  * Currently, we have:
  39  *      -mfloat-abi=
  40  *      -march=
  41  *      -mcpu=
  42  */
  43 #define EXCLUSIVE_ARGS  3
  44
  45 static char *predef_args[] = {
  46 #ifdef BR_CCACHE
  47         ccache_path,
  48 #endif
  49         path,
  50         "--sysroot", sysroot,
  51 #ifdef BR_ABI
  52         "-mabi=" BR_ABI,
  53 #endif
  54 #ifdef BR_FPU
  55         "-mfpu=" BR_FPU,
  56 #endif
  57 #ifdef BR_SOFTFLOAT
  58         "-msoft-float",
  59 #endif /* BR_SOFTFLOAT */
  60 #ifdef BR_MODE
  61         "-m" BR_MODE,
  62 #endif
  63 #ifdef BR_64
  64         "-m64",
  65 #endif
  66 #ifdef BR_OMIT_LOCK_PREFIX
  67         "-Wa,-momit-lock-prefix=yes",
  68 #endif
  69 #ifdef BR_BINFMT_FLAT
  70         "-Wl,-elf2flt",
  71 #endif
  72 #ifdef BR_MIPS_TARGET_LITTLE_ENDIAN
  73         "-EL",
  74 #endif
  75 #if defined(BR_MIPS_TARGET_BIG_ENDIAN) || defined(BR_ARC_TARGET_BIG_ENDIAN)
  76         "-EB",
  77 #endif
  78 #ifdef BR_ADDITIONAL_CFLAGS
  79         BR_ADDITIONAL_CFLAGS
  80 #endif
  81 };
  82
  83 struct unsafe_opt_s {
  84         const char *arg;
  85         size_t     len;
  86 };
  87
  88 /* Unsafe options are options that specify a potentialy unsafe path,
  89  * that will be checked by check_unsafe_path(), below.
  90  *
  91  * sizeof() on a string literal includes the terminating \0.
  92  */
  93 #define UNSAFE_OPT(o) { #o, sizeof(#o)-1 }
  94 static const struct unsafe_opt_s unsafe_opts[] = {
  95         UNSAFE_OPT(-I),
  96         UNSAFE_OPT(-idirafter),
  97         UNSAFE_OPT(-iquote),
  98         UNSAFE_OPT(-isystem),
  99         UNSAFE_OPT(-L),
 100         { NULL, 0 },
 101 };
 102
 103 /* Check if path is unsafe for cross-compilation. Unsafe paths are those
 104  * pointing to the standard native include or library paths.
 105  *
 106  * We print the arguments leading to the failure. For some options, gcc
 107  * accepts the path to be concatenated to the argument (e.g. -I/foo/bar)
 108  * or separated (e.g. -I /foo/bar). In the first case, we need only print
 109  * the argument as it already contains the path (arg_has_path), while in
 110  * the second case we need to print both (!arg_has_path).
 111  *
 112  * If paranoid, exit in error instead of just printing a warning.
 113  */
 114 static void check_unsafe_path(const char *arg,
 115                               const char *path,
 116                               int paranoid,
 117                               int arg_has_path)
 118 {
 119         char **c;
 120         static char *unsafe_paths[] = {
 121                 "/lib", "/usr/include", "/usr/lib", "/usr/local/include", "/usr/local/lib", NULL,
 122         };
 123
 124         for (c = unsafe_paths; *c != NULL; c++) {
 125                 if (strncmp(path, *c, strlen(*c)))
 126                         continue;
 127                 fprintf(stderr,
 128                         "%s: %s: unsafe header/library path used in cross-compilation: '%s%s%s'\n",
 129                         program_invocation_short_name,
 130                         paranoid ? "ERROR" : "WARNING",
 131                         arg,
 132                         arg_has_path ? "" : "' '", /* close single-quote, space, open single-quote */
 133                         arg_has_path ? "" : path); /* so that arg and path are properly quoted. */
 134                 if (paranoid)
 135                         exit(1);
 136         }
 137 }
 138
 139 int main(int argc, char **argv)
 140 {
 141         char **args, **cur, **exec_args;
 142         char *relbasedir, *absbasedir;
 143         char *progpath = argv[0];
 144         char *basename;
 145         char *env_debug;
 146         char *paranoid_wrapper;
 147         int paranoid;
 148         int ret, i, count = 0, debug;
 149
 150         /* Calculate the relative paths */
 151         basename = strrchr(progpath, '/');
 152         if (basename) {
 153                 *basename = '\0';
 154                 basename++;
 155                 relbasedir = malloc(strlen(progpath) + 7);
 156                 if (relbasedir == NULL) {
 157                         perror(__FILE__ ": malloc");
 158                         return 2;
 159                 }
 160                 sprintf(relbasedir, "%s/../..", argv[0]);
 161                 absbasedir = realpath(relbasedir, NULL);
 162         } else {
 163                 basename = progpath;
 164                 absbasedir = malloc(PATH_MAX + 1);
 165                 ret = readlink("/proc/self/exe", absbasedir, PATH_MAX);
 166                 if (ret < 0) {
 167                         perror(__FILE__ ": readlink");
 168                         return 2;
 169                 }
 170                 absbasedir[ret] = '\0';
 171                 for (i = ret; i > 0; i--) {
 172                         if (absbasedir[i] == '/') {
 173                                 absbasedir[i] = '\0';
 174                                 if (++count == 3)
 175                                         break;
 176                         }
 177                 }
 178         }
 179         if (absbasedir == NULL) {
 180                 perror(__FILE__ ": realpath");
 181                 return 2;
 182         }
 183
 184         /* Fill in the relative paths */
 185 #ifdef BR_CROSS_PATH_REL
 186         ret = snprintf(path, sizeof(path), "%s/" BR_CROSS_PATH_REL "/%s" BR_CROSS_PATH_SUFFIX, absbasedir, basename);
 187 #elif defined(BR_CROSS_PATH_ABS)
 188         ret = snprintf(path, sizeof(path), BR_CROSS_PATH_ABS "/%s" BR_CROSS_PATH_SUFFIX, basename);
 189 #else
 190         ret = snprintf(path, sizeof(path), "%s/usr/bin/%s" BR_CROSS_PATH_SUFFIX, absbasedir, basename);
 191 #endif
 192         if (ret >= sizeof(path)) {
 193                 perror(__FILE__ ": overflow");
 194                 return 3;
 195         }
 196 #ifdef BR_CCACHE
 197         ret = snprintf(ccache_path, sizeof(ccache_path), "%s/usr/bin/ccache", absbasedir);
 198         if (ret >= sizeof(ccache_path)) {
 199                 perror(__FILE__ ": overflow");
 200                 return 3;
 201         }
 202 #endif
 203         ret = snprintf(sysroot, sizeof(sysroot), "%s/" BR_SYSROOT, absbasedir);
 204         if (ret >= sizeof(sysroot)) {
 205                 perror(__FILE__ ": overflow");
 206                 return 3;
 207         }
 208
 209         cur = args = malloc(sizeof(predef_args) +
 210                             (sizeof(char *) * (argc + EXCLUSIVE_ARGS)));
 211         if (args == NULL) {
 212                 perror(__FILE__ ": malloc");
 213                 return 2;
 214         }
 215
 216         /* start with predefined args */
 217         memcpy(cur, predef_args, sizeof(predef_args));
 218         cur += sizeof(predef_args) / sizeof(predef_args[0]);
 219
 220 #ifdef BR_FLOAT_ABI
 221         /* add float abi if not overridden in args */
 222         for (i = 1; i < argc; i++) {
 223                 if (!strncmp(argv[i], "-mfloat-abi=", strlen("-mfloat-abi=")) ||
 224                     !strcmp(argv[i], "-msoft-float") ||
 225                     !strcmp(argv[i], "-mhard-float"))
 226                         break;
 227         }
 228
 229         if (i == argc)
 230                 *cur++ = "-mfloat-abi=" BR_FLOAT_ABI;
 231 #endif
 232
 233 #if defined(BR_ARCH) || \
 234     defined(BR_CPU)
 235         /* Add our -march/cpu flags, but only if none of
 236          * -march/mtune/mcpu are already specified on the commandline
 237          */
 238         for (i = 1; i < argc; i++) {
 239                 if (!strncmp(argv[i], "-march=", strlen("-march=")) ||
 240                     !strncmp(argv[i], "-mtune=", strlen("-mtune=")) ||
 241                     !strncmp(argv[i], "-mcpu=",  strlen("-mcpu=" )))
 242                         break;
 243         }
 244         if (i == argc) {
 245 #ifdef BR_ARCH
 246                 *cur++ = "-march=" BR_ARCH;
 247 #endif
 248 #ifdef BR_CPU
 249                 *cur++ = "-mcpu=" BR_CPU;
 250 #endif
 251         }
 252 #endif /* ARCH || CPU */
 253
 254         paranoid_wrapper = getenv("BR_COMPILER_PARANOID_UNSAFE_PATH");
 255         if (paranoid_wrapper && strlen(paranoid_wrapper) > 0)
 256                 paranoid = 1;
 257         else
 258                 paranoid = 0;
 259
 260         /* Check for unsafe library and header paths */
 261         for (i = 1; i < argc; i++) {
 262                 const struct unsafe_opt_s *opt;
 263                 for (opt=unsafe_opts; opt->arg; opt++ ) {
 264                         /* Skip any non-unsafe option. */
 265                         if (strncmp(argv[i], opt->arg, opt->len))
 266                                 continue;
 267
 268                         /* Handle both cases:
 269                          *  - path is a separate argument,
 270                          *  - path is concatenated with option.
 271                          */
 272                         if (argv[i][opt->len] == '\0') {
 273                                 i++;
 274                                 if (i == argc)
 275                                         break;
 276                                 check_unsafe_path(argv[i-1], argv[i], paranoid, 0);
 277                         } else
 278                                 check_unsafe_path(argv[i], argv[i] + opt->len, paranoid, 1);
 279                 }
 280         }
 281
 282         /* append forward args */
 283         memcpy(cur, &argv[1], sizeof(char *) * (argc - 1));
 284         cur += argc - 1;
 285
 286         /* finish with NULL termination */
 287         *cur = NULL;
 288
 289         exec_args = args;
 290 #ifdef BR_CCACHE
 291         if (getenv("BR_NO_CCACHE"))
 292                 /* Skip the ccache call */
 293                 exec_args++;
 294 #endif
 295
 296         /* Debug the wrapper to see actual arguments passed to
 297          * the compiler:
 298          * unset, empty, or 0: do not trace
 299          * set to 1          : trace all arguments on a single line
 300          * set to 2          : trace one argument per line
 301          */
 302         if ((env_debug = getenv("BR2_DEBUG_WRAPPER"))) {
 303                 debug = atoi(env_debug);
 304                 if (debug > 0) {
 305                         fprintf(stderr, "Toolchain wrapper executing:");
 306 #ifdef BR_CCACHE_HASH
 307                         fprintf(stderr, "%sCCACHE_COMPILERCHECK='string:" BR_CCACHE_HASH "'",
 308                                 (debug == 2) ? "\n    " : " ");
 309 #endif
 310 #ifdef BR_CCACHE_BASEDIR
 311                         fprintf(stderr, "%sCCACHE_BASEDIR='" BR_CCACHE_BASEDIR "'",
 312                                 (debug == 2) ? "\n    " : " ");
 313 #endif
 314                         for (i = 0; exec_args[i]; i++)
 315                                 fprintf(stderr, "%s'%s'",
 316                                         (debug == 2) ? "\n    " : " ", exec_args[i]);
 317                         fprintf(stderr, "\n");
 318                 }
 319         }
 320
 321 #ifdef BR_CCACHE_HASH
 322         /* Allow compilercheck to be overridden through the environment */
 323         if (setenv("CCACHE_COMPILERCHECK", "string:" BR_CCACHE_HASH, 0)) {
 324                 perror(__FILE__ ": Failed to set CCACHE_COMPILERCHECK");
 325                 return 3;
 326         }
 327 #endif
 328 #ifdef BR_CCACHE_BASEDIR
 329         /* Allow compilercheck to be overridden through the environment */
 330         if (setenv("CCACHE_BASEDIR", BR_CCACHE_BASEDIR, 0)) {
 331                 perror(__FILE__ ": Failed to set CCACHE_BASEDIR");
 332                 return 3;
 333         }
 334 #endif
 335
 336         if (execv(exec_args[0], exec_args))
 337                 perror(path);
 338
 339         free(args);
 340
 341         return 2;
 342 }