| 1 | /* Relative (relocatable) prefix support. |
| 2 | Copyright (C) 1987-2019 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of libiberty. |
| 5 | |
| 6 | GCC is free software; you can redistribute it and/or modify it under |
| 7 | the terms of the GNU General Public License as published by the Free |
| 8 | Software Foundation; either version 2, or (at your option) any later |
| 9 | version. |
| 10 | |
| 11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| 12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GCC; see the file COPYING. If not, write to the Free |
| 18 | Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA |
| 19 | 02110-1301, USA. */ |
| 20 | |
| 21 | /* |
| 22 | |
| 23 | @deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, @ |
| 24 | const char *@var{bin_prefix}, const char *@var{prefix}) |
| 25 | |
| 26 | Given three paths @var{progname}, @var{bin_prefix}, @var{prefix}, |
| 27 | return the path that is in the same position relative to |
| 28 | @var{progname}'s directory as @var{prefix} is relative to |
| 29 | @var{bin_prefix}. That is, a string starting with the directory |
| 30 | portion of @var{progname}, followed by a relative pathname of the |
| 31 | difference between @var{bin_prefix} and @var{prefix}. |
| 32 | |
| 33 | If @var{progname} does not contain any directory separators, |
| 34 | @code{make_relative_prefix} will search @env{PATH} to find a program |
| 35 | named @var{progname}. Also, if @var{progname} is a symbolic link, |
| 36 | the symbolic link will be resolved. |
| 37 | |
| 38 | For example, if @var{bin_prefix} is @code{/alpha/beta/gamma/gcc/delta}, |
| 39 | @var{prefix} is @code{/alpha/beta/gamma/omega/}, and @var{progname} is |
| 40 | @code{/red/green/blue/gcc}, then this function will return |
| 41 | @code{/red/green/blue/../../omega/}. |
| 42 | |
| 43 | The return value is normally allocated via @code{malloc}. If no |
| 44 | relative prefix can be found, return @code{NULL}. |
| 45 | |
| 46 | @end deftypefn |
| 47 | |
| 48 | */ |
| 49 | |
| 50 | #ifdef HAVE_CONFIG_H |
| 51 | #include "config.h" |
| 52 | #endif |
| 53 | |
| 54 | #ifdef HAVE_STDLIB_H |
| 55 | #include <stdlib.h> |
| 56 | #endif |
| 57 | #ifdef HAVE_UNISTD_H |
| 58 | #include <unistd.h> |
| 59 | #endif |
| 60 | #ifdef HAVE_SYS_STAT_H |
| 61 | #include <sys/stat.h> |
| 62 | #endif |
| 63 | |
| 64 | #include <string.h> |
| 65 | |
| 66 | #include "ansidecl.h" |
| 67 | #include "libiberty.h" |
| 68 | |
| 69 | #ifndef R_OK |
| 70 | #define R_OK 4 |
| 71 | #define W_OK 2 |
| 72 | #define X_OK 1 |
| 73 | #endif |
| 74 | |
| 75 | #ifndef DIR_SEPARATOR |
| 76 | # define DIR_SEPARATOR '/' |
| 77 | #endif |
| 78 | |
| 79 | #if defined (_WIN32) || defined (__MSDOS__) \ |
| 80 | || defined (__DJGPP__) || defined (__OS2__) |
| 81 | # define HAVE_DOS_BASED_FILE_SYSTEM |
| 82 | # define HAVE_HOST_EXECUTABLE_SUFFIX |
| 83 | # define HOST_EXECUTABLE_SUFFIX ".exe" |
| 84 | # ifndef DIR_SEPARATOR_2 |
| 85 | # define DIR_SEPARATOR_2 '\\' |
| 86 | # endif |
| 87 | # define PATH_SEPARATOR ';' |
| 88 | #else |
| 89 | # define PATH_SEPARATOR ':' |
| 90 | #endif |
| 91 | |
| 92 | #ifndef DIR_SEPARATOR_2 |
| 93 | # define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR) |
| 94 | #else |
| 95 | # define IS_DIR_SEPARATOR(ch) \ |
| 96 | (((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2)) |
| 97 | #endif |
| 98 | |
| 99 | #define DIR_UP ".." |
| 100 | |
| 101 | static char *save_string (const char *, int); |
| 102 | static char **split_directories (const char *, int *); |
| 103 | static void free_split_directories (char **); |
| 104 | |
| 105 | static char * |
| 106 | save_string (const char *s, int len) |
| 107 | { |
| 108 | char *result = (char *) malloc (len + 1); |
| 109 | |
| 110 | memcpy (result, s, len); |
| 111 | result[len] = 0; |
| 112 | return result; |
| 113 | } |
| 114 | |
| 115 | /* Split a filename into component directories. */ |
| 116 | |
| 117 | static char ** |
| 118 | split_directories (const char *name, int *ptr_num_dirs) |
| 119 | { |
| 120 | int num_dirs = 0; |
| 121 | char **dirs; |
| 122 | const char *p, *q; |
| 123 | int ch; |
| 124 | |
| 125 | /* Count the number of directories. Special case MSDOS disk names as part |
| 126 | of the initial directory. */ |
| 127 | p = name; |
| 128 | #ifdef HAVE_DOS_BASED_FILE_SYSTEM |
| 129 | if (name[1] == ':' && IS_DIR_SEPARATOR (name[2])) |
| 130 | { |
| 131 | p += 3; |
| 132 | num_dirs++; |
| 133 | } |
| 134 | #endif /* HAVE_DOS_BASED_FILE_SYSTEM */ |
| 135 | |
| 136 | while ((ch = *p++) != '\0') |
| 137 | { |
| 138 | if (IS_DIR_SEPARATOR (ch)) |
| 139 | { |
| 140 | num_dirs++; |
| 141 | while (IS_DIR_SEPARATOR (*p)) |
| 142 | p++; |
| 143 | } |
| 144 | } |
| 145 | |
| 146 | dirs = (char **) malloc (sizeof (char *) * (num_dirs + 2)); |
| 147 | if (dirs == NULL) |
| 148 | return NULL; |
| 149 | |
| 150 | /* Now copy the directory parts. */ |
| 151 | num_dirs = 0; |
| 152 | p = name; |
| 153 | #ifdef HAVE_DOS_BASED_FILE_SYSTEM |
| 154 | if (name[1] == ':' && IS_DIR_SEPARATOR (name[2])) |
| 155 | { |
| 156 | dirs[num_dirs++] = save_string (p, 3); |
| 157 | if (dirs[num_dirs - 1] == NULL) |
| 158 | { |
| 159 | free (dirs); |
| 160 | return NULL; |
| 161 | } |
| 162 | p += 3; |
| 163 | } |
| 164 | #endif /* HAVE_DOS_BASED_FILE_SYSTEM */ |
| 165 | |
| 166 | q = p; |
| 167 | while ((ch = *p++) != '\0') |
| 168 | { |
| 169 | if (IS_DIR_SEPARATOR (ch)) |
| 170 | { |
| 171 | while (IS_DIR_SEPARATOR (*p)) |
| 172 | p++; |
| 173 | |
| 174 | dirs[num_dirs++] = save_string (q, p - q); |
| 175 | if (dirs[num_dirs - 1] == NULL) |
| 176 | { |
| 177 | dirs[num_dirs] = NULL; |
| 178 | free_split_directories (dirs); |
| 179 | return NULL; |
| 180 | } |
| 181 | q = p; |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | if (p - 1 - q > 0) |
| 186 | dirs[num_dirs++] = save_string (q, p - 1 - q); |
| 187 | dirs[num_dirs] = NULL; |
| 188 | |
| 189 | if (dirs[num_dirs - 1] == NULL) |
| 190 | { |
| 191 | free_split_directories (dirs); |
| 192 | return NULL; |
| 193 | } |
| 194 | |
| 195 | if (ptr_num_dirs) |
| 196 | *ptr_num_dirs = num_dirs; |
| 197 | return dirs; |
| 198 | } |
| 199 | |
| 200 | /* Release storage held by split directories. */ |
| 201 | |
| 202 | static void |
| 203 | free_split_directories (char **dirs) |
| 204 | { |
| 205 | int i = 0; |
| 206 | |
| 207 | if (dirs != NULL) |
| 208 | { |
| 209 | while (dirs[i] != NULL) |
| 210 | free (dirs[i++]); |
| 211 | |
| 212 | free ((char *) dirs); |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | /* Given three strings PROGNAME, BIN_PREFIX, PREFIX, return a string that gets |
| 217 | to PREFIX starting with the directory portion of PROGNAME and a relative |
| 218 | pathname of the difference between BIN_PREFIX and PREFIX. |
| 219 | |
| 220 | For example, if BIN_PREFIX is /alpha/beta/gamma/gcc/delta, PREFIX is |
| 221 | /alpha/beta/gamma/omega/, and PROGNAME is /red/green/blue/gcc, then this |
| 222 | function will return /red/green/blue/../../omega/. |
| 223 | |
| 224 | If no relative prefix can be found, return NULL. */ |
| 225 | |
| 226 | static char * |
| 227 | make_relative_prefix_1 (const char *progname, const char *bin_prefix, |
| 228 | const char *prefix, const int resolve_links) |
| 229 | { |
| 230 | char **prog_dirs = NULL, **bin_dirs = NULL, **prefix_dirs = NULL; |
| 231 | int prog_num, bin_num, prefix_num; |
| 232 | int i, n, common; |
| 233 | int needed_len; |
| 234 | char *ret = NULL, *ptr, *full_progname; |
| 235 | char *alloc_ptr = NULL; |
| 236 | |
| 237 | if (progname == NULL || bin_prefix == NULL || prefix == NULL) |
| 238 | return NULL; |
| 239 | |
| 240 | /* If there is no full pathname, try to find the program by checking in each |
| 241 | of the directories specified in the PATH environment variable. */ |
| 242 | if (lbasename (progname) == progname) |
| 243 | { |
| 244 | char *temp; |
| 245 | |
| 246 | temp = getenv ("PATH"); |
| 247 | if (temp) |
| 248 | { |
| 249 | char *startp, *endp, *nstore; |
| 250 | size_t prefixlen = strlen (temp) + 1; |
| 251 | size_t len; |
| 252 | if (prefixlen < 2) |
| 253 | prefixlen = 2; |
| 254 | |
| 255 | len = prefixlen + strlen (progname) + 1; |
| 256 | #ifdef HAVE_HOST_EXECUTABLE_SUFFIX |
| 257 | len += strlen (HOST_EXECUTABLE_SUFFIX); |
| 258 | #endif |
| 259 | if (len < MAX_ALLOCA_SIZE) |
| 260 | nstore = (char *) alloca (len); |
| 261 | else |
| 262 | alloc_ptr = nstore = (char *) malloc (len); |
| 263 | |
| 264 | startp = endp = temp; |
| 265 | while (1) |
| 266 | { |
| 267 | if (*endp == PATH_SEPARATOR || *endp == 0) |
| 268 | { |
| 269 | if (endp == startp) |
| 270 | { |
| 271 | nstore[0] = '.'; |
| 272 | nstore[1] = DIR_SEPARATOR; |
| 273 | nstore[2] = '\0'; |
| 274 | } |
| 275 | else |
| 276 | { |
| 277 | memcpy (nstore, startp, endp - startp); |
| 278 | if (! IS_DIR_SEPARATOR (endp[-1])) |
| 279 | { |
| 280 | nstore[endp - startp] = DIR_SEPARATOR; |
| 281 | nstore[endp - startp + 1] = 0; |
| 282 | } |
| 283 | else |
| 284 | nstore[endp - startp] = 0; |
| 285 | } |
| 286 | strcat (nstore, progname); |
| 287 | if (! access (nstore, X_OK) |
| 288 | #ifdef HAVE_HOST_EXECUTABLE_SUFFIX |
| 289 | || ! access (strcat (nstore, HOST_EXECUTABLE_SUFFIX), X_OK) |
| 290 | #endif |
| 291 | ) |
| 292 | { |
| 293 | #if defined (HAVE_SYS_STAT_H) && defined (S_ISREG) |
| 294 | struct stat st; |
| 295 | if (stat (nstore, &st) >= 0 && S_ISREG (st.st_mode)) |
| 296 | #endif |
| 297 | { |
| 298 | progname = nstore; |
| 299 | break; |
| 300 | } |
| 301 | } |
| 302 | |
| 303 | if (*endp == 0) |
| 304 | break; |
| 305 | endp = startp = endp + 1; |
| 306 | } |
| 307 | else |
| 308 | endp++; |
| 309 | } |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | if (resolve_links) |
| 314 | full_progname = lrealpath (progname); |
| 315 | else |
| 316 | full_progname = strdup (progname); |
| 317 | if (full_progname == NULL) |
| 318 | goto bailout; |
| 319 | |
| 320 | prog_dirs = split_directories (full_progname, &prog_num); |
| 321 | free (full_progname); |
| 322 | if (prog_dirs == NULL) |
| 323 | goto bailout; |
| 324 | |
| 325 | bin_dirs = split_directories (bin_prefix, &bin_num); |
| 326 | if (bin_dirs == NULL) |
| 327 | goto bailout; |
| 328 | |
| 329 | /* Remove the program name from comparison of directory names. */ |
| 330 | prog_num--; |
| 331 | |
| 332 | /* If we are still installed in the standard location, we don't need to |
| 333 | specify relative directories. Also, if argv[0] still doesn't contain |
| 334 | any directory specifiers after the search above, then there is not much |
| 335 | we can do. */ |
| 336 | if (prog_num == bin_num) |
| 337 | { |
| 338 | for (i = 0; i < bin_num; i++) |
| 339 | { |
| 340 | if (strcmp (prog_dirs[i], bin_dirs[i]) != 0) |
| 341 | break; |
| 342 | } |
| 343 | |
| 344 | if (prog_num <= 0 || i == bin_num) |
| 345 | goto bailout; |
| 346 | } |
| 347 | |
| 348 | prefix_dirs = split_directories (prefix, &prefix_num); |
| 349 | if (prefix_dirs == NULL) |
| 350 | goto bailout; |
| 351 | |
| 352 | /* Find how many directories are in common between bin_prefix & prefix. */ |
| 353 | n = (prefix_num < bin_num) ? prefix_num : bin_num; |
| 354 | for (common = 0; common < n; common++) |
| 355 | { |
| 356 | if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0) |
| 357 | break; |
| 358 | } |
| 359 | |
| 360 | /* If there are no common directories, there can be no relative prefix. */ |
| 361 | if (common == 0) |
| 362 | goto bailout; |
| 363 | |
| 364 | /* Two passes: first figure out the size of the result string, and |
| 365 | then construct it. */ |
| 366 | needed_len = 0; |
| 367 | for (i = 0; i < prog_num; i++) |
| 368 | needed_len += strlen (prog_dirs[i]); |
| 369 | needed_len += sizeof (DIR_UP) * (bin_num - common); |
| 370 | for (i = common; i < prefix_num; i++) |
| 371 | needed_len += strlen (prefix_dirs[i]); |
| 372 | needed_len += 1; /* Trailing NUL. */ |
| 373 | |
| 374 | ret = (char *) malloc (needed_len); |
| 375 | if (ret == NULL) |
| 376 | goto bailout; |
| 377 | |
| 378 | /* Build up the pathnames in argv[0]. */ |
| 379 | *ret = '\0'; |
| 380 | for (i = 0; i < prog_num; i++) |
| 381 | strcat (ret, prog_dirs[i]); |
| 382 | |
| 383 | /* Now build up the ..'s. */ |
| 384 | ptr = ret + strlen(ret); |
| 385 | for (i = common; i < bin_num; i++) |
| 386 | { |
| 387 | strcpy (ptr, DIR_UP); |
| 388 | ptr += sizeof (DIR_UP) - 1; |
| 389 | *(ptr++) = DIR_SEPARATOR; |
| 390 | } |
| 391 | *ptr = '\0'; |
| 392 | |
| 393 | /* Put in directories to move over to prefix. */ |
| 394 | for (i = common; i < prefix_num; i++) |
| 395 | strcat (ret, prefix_dirs[i]); |
| 396 | |
| 397 | bailout: |
| 398 | free_split_directories (prog_dirs); |
| 399 | free_split_directories (bin_dirs); |
| 400 | free_split_directories (prefix_dirs); |
| 401 | free (alloc_ptr); |
| 402 | |
| 403 | return ret; |
| 404 | } |
| 405 | |
| 406 | |
| 407 | /* Do the full job, including symlink resolution. |
| 408 | This path will find files installed in the same place as the |
| 409 | program even when a soft link has been made to the program |
| 410 | from somwhere else. */ |
| 411 | |
| 412 | char * |
| 413 | make_relative_prefix (const char *progname, const char *bin_prefix, |
| 414 | const char *prefix) |
| 415 | { |
| 416 | return make_relative_prefix_1 (progname, bin_prefix, prefix, 1); |
| 417 | } |
| 418 | |
| 419 | /* Make the relative pathname without attempting to resolve any links. |
| 420 | '..' etc may also be left in the pathname. |
| 421 | This will find the files the user meant the program to find if the |
| 422 | installation is patched together with soft links. */ |
| 423 | |
| 424 | char * |
| 425 | make_relative_prefix_ignore_links (const char *progname, |
| 426 | const char *bin_prefix, |
| 427 | const char *prefix) |
| 428 | { |
| 429 | return make_relative_prefix_1 (progname, bin_prefix, prefix, 0); |
| 430 | } |
| 431 | |