PR target/81369
[official-gcc.git] / libiberty / make-relative-prefix.c
blobf74bbdc9038e3c55507d81a3e8abc5ae826c6c6a
1 /* Relative (relocatable) prefix support.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
4 This file is part of libiberty.
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.
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.
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. */
23 @deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, @
24 const char *@var{bin_prefix}, const char *@var{prefix})
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}.
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.
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/}.
43 The return value is normally allocated via @code{malloc}. If no
44 relative prefix can be found, return @code{NULL}.
46 @end deftypefn
50 #ifdef HAVE_CONFIG_H
51 #include "config.h"
52 #endif
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
64 #include <string.h>
66 #include "ansidecl.h"
67 #include "libiberty.h"
69 #ifndef R_OK
70 #define R_OK 4
71 #define W_OK 2
72 #define X_OK 1
73 #endif
75 #ifndef DIR_SEPARATOR
76 # define DIR_SEPARATOR '/'
77 #endif
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
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
99 #define DIR_UP ".."
101 static char *save_string (const char *, int);
102 static char **split_directories (const char *, int *);
103 static void free_split_directories (char **);
105 static char *
106 save_string (const char *s, int len)
108 char *result = (char *) malloc (len + 1);
110 memcpy (result, s, len);
111 result[len] = 0;
112 return result;
115 /* Split a filename into component directories. */
117 static char **
118 split_directories (const char *name, int *ptr_num_dirs)
120 int num_dirs = 0;
121 char **dirs;
122 const char *p, *q;
123 int ch;
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]))
131 p += 3;
132 num_dirs++;
134 #endif /* HAVE_DOS_BASED_FILE_SYSTEM */
136 while ((ch = *p++) != '\0')
138 if (IS_DIR_SEPARATOR (ch))
140 num_dirs++;
141 while (IS_DIR_SEPARATOR (*p))
142 p++;
146 dirs = (char **) malloc (sizeof (char *) * (num_dirs + 2));
147 if (dirs == NULL)
148 return NULL;
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]))
156 dirs[num_dirs++] = save_string (p, 3);
157 if (dirs[num_dirs - 1] == NULL)
159 free (dirs);
160 return NULL;
162 p += 3;
164 #endif /* HAVE_DOS_BASED_FILE_SYSTEM */
166 q = p;
167 while ((ch = *p++) != '\0')
169 if (IS_DIR_SEPARATOR (ch))
171 while (IS_DIR_SEPARATOR (*p))
172 p++;
174 dirs[num_dirs++] = save_string (q, p - q);
175 if (dirs[num_dirs - 1] == NULL)
177 dirs[num_dirs] = NULL;
178 free_split_directories (dirs);
179 return NULL;
181 q = p;
185 if (p - 1 - q > 0)
186 dirs[num_dirs++] = save_string (q, p - 1 - q);
187 dirs[num_dirs] = NULL;
189 if (dirs[num_dirs - 1] == NULL)
191 free_split_directories (dirs);
192 return NULL;
195 if (ptr_num_dirs)
196 *ptr_num_dirs = num_dirs;
197 return dirs;
200 /* Release storage held by split directories. */
202 static void
203 free_split_directories (char **dirs)
205 int i = 0;
207 if (dirs != NULL)
209 while (dirs[i] != NULL)
210 free (dirs[i++]);
212 free ((char *) dirs);
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.
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/.
224 If no relative prefix can be found, return NULL. */
226 static char *
227 make_relative_prefix_1 (const char *progname, const char *bin_prefix,
228 const char *prefix, const int resolve_links)
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;
237 if (progname == NULL || bin_prefix == NULL || prefix == NULL)
238 return NULL;
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)
244 char *temp;
246 temp = getenv ("PATH");
247 if (temp)
249 char *startp, *endp, *nstore;
250 size_t prefixlen = strlen (temp) + 1;
251 size_t len;
252 if (prefixlen < 2)
253 prefixlen = 2;
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);
264 startp = endp = temp;
265 while (1)
267 if (*endp == PATH_SEPARATOR || *endp == 0)
269 if (endp == startp)
271 nstore[0] = '.';
272 nstore[1] = DIR_SEPARATOR;
273 nstore[2] = '\0';
275 else
277 memcpy (nstore, startp, endp - startp);
278 if (! IS_DIR_SEPARATOR (endp[-1]))
280 nstore[endp - startp] = DIR_SEPARATOR;
281 nstore[endp - startp + 1] = 0;
283 else
284 nstore[endp - startp] = 0;
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
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
298 progname = nstore;
299 break;
303 if (*endp == 0)
304 break;
305 endp = startp = endp + 1;
307 else
308 endp++;
313 if (resolve_links)
314 full_progname = lrealpath (progname);
315 else
316 full_progname = strdup (progname);
317 if (full_progname == NULL)
318 goto bailout;
320 prog_dirs = split_directories (full_progname, &prog_num);
321 free (full_progname);
322 if (prog_dirs == NULL)
323 goto bailout;
325 bin_dirs = split_directories (bin_prefix, &bin_num);
326 if (bin_dirs == NULL)
327 goto bailout;
329 /* Remove the program name from comparison of directory names. */
330 prog_num--;
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)
338 for (i = 0; i < bin_num; i++)
340 if (strcmp (prog_dirs[i], bin_dirs[i]) != 0)
341 break;
344 if (prog_num <= 0 || i == bin_num)
345 goto bailout;
348 prefix_dirs = split_directories (prefix, &prefix_num);
349 if (prefix_dirs == NULL)
350 goto bailout;
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++)
356 if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0)
357 break;
360 /* If there are no common directories, there can be no relative prefix. */
361 if (common == 0)
362 goto bailout;
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. */
374 ret = (char *) malloc (needed_len);
375 if (ret == NULL)
376 goto bailout;
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]);
383 /* Now build up the ..'s. */
384 ptr = ret + strlen(ret);
385 for (i = common; i < bin_num; i++)
387 strcpy (ptr, DIR_UP);
388 ptr += sizeof (DIR_UP) - 1;
389 *(ptr++) = DIR_SEPARATOR;
391 *ptr = '\0';
393 /* Put in directories to move over to prefix. */
394 for (i = common; i < prefix_num; i++)
395 strcat (ret, prefix_dirs[i]);
397 bailout:
398 free_split_directories (prog_dirs);
399 free_split_directories (bin_dirs);
400 free_split_directories (prefix_dirs);
401 free (alloc_ptr);
403 return ret;
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. */
412 char *
413 make_relative_prefix (const char *progname, const char *bin_prefix,
414 const char *prefix)
416 return make_relative_prefix_1 (progname, bin_prefix, prefix, 1);
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. */
424 char *
425 make_relative_prefix_ignore_links (const char *progname,
426 const char *bin_prefix,
427 const char *prefix)
429 return make_relative_prefix_1 (progname, bin_prefix, prefix, 0);