1 /* Relative (relocatable) prefix support.
2 Copyright (C) 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2006, 2012 Free Software Foundation, Inc.
4
5 This file is part of libiberty.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
20 02110-1301, USA. */
21
22 /*
23
24 @deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, @
25 const char *@var{bin_prefix}, const char *@var{prefix})
26
27 Given three paths @var{progname}, @var{bin_prefix}, @var{prefix},
28 return the path that is in the same position relative to
29 @var{progname}'s directory as @var{prefix} is relative to
30 @var{bin_prefix}. That is, a string starting with the directory
31 portion of @var{progname}, followed by a relative pathname of the
32 difference between @var{bin_prefix} and @var{prefix}.
33
34 If @var{progname} does not contain any directory separators,
35 @code{make_relative_prefix} will search @env{PATH} to find a program
36 named @var{progname}. Also, if @var{progname} is a symbolic link,
37 the symbolic link will be resolved.
38
39 For example, if @var{bin_prefix} is @code{/alpha/beta/gamma/gcc/delta},
40 @var{prefix} is @code{/alpha/beta/gamma/omega/}, and @var{progname} is
41 @code{/red/green/blue/gcc}, then this function will return
42 @code{/red/green/blue/../../omega/}.
43
44 The return value is normally allocated via @code{malloc}. If no
45 relative prefix can be found, return @code{NULL}.
46
47 @end deftypefn
48
49 */
50
51 #ifdef HAVE_CONFIG_H
52 #include "config.h"
53 #endif
54
55 #ifdef HAVE_STDLIB_H
56 #include <stdlib.h>
57 #endif
58 #ifdef HAVE_UNISTD_H
59 #include <unistd.h>
60 #endif
61 #ifdef HAVE_SYS_STAT_H
62 #include <sys/stat.h>
63 #endif
64
65 #include <string.h>
66
67 #include "ansidecl.h"
68 #include "libiberty.h"
69
70 #ifndef R_OK
71 #define R_OK 4
72 #define W_OK 2
73 #define X_OK 1
74 #endif
75
76 #ifndef DIR_SEPARATOR
77 # define DIR_SEPARATOR '/'
78 #endif
79
80 #if defined (_WIN32) || defined (__MSDOS__) \
81 || defined (__DJGPP__) || defined (__OS2__)
82 # define HAVE_DOS_BASED_FILE_SYSTEM
83 # define HAVE_HOST_EXECUTABLE_SUFFIX
84 # define HOST_EXECUTABLE_SUFFIX ".exe"
85 # ifndef DIR_SEPARATOR_2
86 # define DIR_SEPARATOR_2 '\\'
87 # endif
88 # define PATH_SEPARATOR ';'
89 #else
90 # define PATH_SEPARATOR ':'
91 #endif
92
93 #ifndef DIR_SEPARATOR_2
94 # define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
95 #else
96 # define IS_DIR_SEPARATOR(ch) \
97 (((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
98 #endif
99
100 #define DIR_UP ".."
101
102 static char *save_string (const char *, int);
103 static char **split_directories (const char *, int *);
104 static void free_split_directories (char **);
105
106 static char *
save_string(const char * s,int len)107 save_string (const char *s, int len)
108 {
109 char *result = (char *) malloc (len + 1);
110
111 memcpy (result, s, len);
112 result[len] = 0;
113 return result;
114 }
115
116 /* Split a filename into component directories. */
117
118 static char **
split_directories(const char * name,int * ptr_num_dirs)119 split_directories (const char *name, int *ptr_num_dirs)
120 {
121 int num_dirs = 0;
122 char **dirs;
123 const char *p, *q;
124 int ch;
125
126 /* Count the number of directories. Special case MSDOS disk names as part
127 of the initial directory. */
128 p = name;
129 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
130 if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
131 {
132 p += 3;
133 num_dirs++;
134 }
135 #endif /* HAVE_DOS_BASED_FILE_SYSTEM */
136
137 while ((ch = *p++) != '\0')
138 {
139 if (IS_DIR_SEPARATOR (ch))
140 {
141 num_dirs++;
142 while (IS_DIR_SEPARATOR (*p))
143 p++;
144 }
145 }
146
147 dirs = (char **) malloc (sizeof (char *) * (num_dirs + 2));
148 if (dirs == NULL)
149 return NULL;
150
151 /* Now copy the directory parts. */
152 num_dirs = 0;
153 p = name;
154 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
155 if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
156 {
157 dirs[num_dirs++] = save_string (p, 3);
158 if (dirs[num_dirs - 1] == NULL)
159 {
160 free (dirs);
161 return NULL;
162 }
163 p += 3;
164 }
165 #endif /* HAVE_DOS_BASED_FILE_SYSTEM */
166
167 q = p;
168 while ((ch = *p++) != '\0')
169 {
170 if (IS_DIR_SEPARATOR (ch))
171 {
172 while (IS_DIR_SEPARATOR (*p))
173 p++;
174
175 dirs[num_dirs++] = save_string (q, p - q);
176 if (dirs[num_dirs - 1] == NULL)
177 {
178 dirs[num_dirs] = NULL;
179 free_split_directories (dirs);
180 return NULL;
181 }
182 q = p;
183 }
184 }
185
186 if (p - 1 - q > 0)
187 dirs[num_dirs++] = save_string (q, p - 1 - q);
188 dirs[num_dirs] = NULL;
189
190 if (dirs[num_dirs - 1] == NULL)
191 {
192 free_split_directories (dirs);
193 return NULL;
194 }
195
196 if (ptr_num_dirs)
197 *ptr_num_dirs = num_dirs;
198 return dirs;
199 }
200
201 /* Release storage held by split directories. */
202
203 static void
free_split_directories(char ** dirs)204 free_split_directories (char **dirs)
205 {
206 int i = 0;
207
208 if (dirs != NULL)
209 {
210 while (dirs[i] != NULL)
211 free (dirs[i++]);
212
213 free ((char *) dirs);
214 }
215 }
216
217 /* Given three strings PROGNAME, BIN_PREFIX, PREFIX, return a string that gets
218 to PREFIX starting with the directory portion of PROGNAME and a relative
219 pathname of the difference between BIN_PREFIX and PREFIX.
220
221 For example, if BIN_PREFIX is /alpha/beta/gamma/gcc/delta, PREFIX is
222 /alpha/beta/gamma/omega/, and PROGNAME is /red/green/blue/gcc, then this
223 function will return /red/green/blue/../../omega/.
224
225 If no relative prefix can be found, return NULL. */
226
227 static char *
make_relative_prefix_1(const char * progname,const char * bin_prefix,const char * prefix,const int resolve_links)228 make_relative_prefix_1 (const char *progname, const char *bin_prefix,
229 const char *prefix, const int resolve_links)
230 {
231 char **prog_dirs = NULL, **bin_dirs = NULL, **prefix_dirs = NULL;
232 int prog_num, bin_num, prefix_num;
233 int i, n, common;
234 int needed_len;
235 char *ret = NULL, *ptr, *full_progname;
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 nstore = (char *) alloca (len);
260
261 startp = endp = temp;
262 while (1)
263 {
264 if (*endp == PATH_SEPARATOR || *endp == 0)
265 {
266 if (endp == startp)
267 {
268 nstore[0] = '.';
269 nstore[1] = DIR_SEPARATOR;
270 nstore[2] = '\0';
271 }
272 else
273 {
274 memcpy (nstore, startp, endp - startp);
275 if (! IS_DIR_SEPARATOR (endp[-1]))
276 {
277 nstore[endp - startp] = DIR_SEPARATOR;
278 nstore[endp - startp + 1] = 0;
279 }
280 else
281 nstore[endp - startp] = 0;
282 }
283 strcat (nstore, progname);
284 if (! access (nstore, X_OK)
285 #ifdef HAVE_HOST_EXECUTABLE_SUFFIX
286 || ! access (strcat (nstore, HOST_EXECUTABLE_SUFFIX), X_OK)
287 #endif
288 )
289 {
290 #if defined (HAVE_SYS_STAT_H) && defined (S_ISREG)
291 struct stat st;
292 if (stat (nstore, &st) >= 0 && S_ISREG (st.st_mode))
293 #endif
294 {
295 progname = nstore;
296 break;
297 }
298 }
299
300 if (*endp == 0)
301 break;
302 endp = startp = endp + 1;
303 }
304 else
305 endp++;
306 }
307 }
308 }
309
310 if (resolve_links)
311 full_progname = lrealpath (progname);
312 else
313 full_progname = strdup (progname);
314 if (full_progname == NULL)
315 return NULL;
316
317 prog_dirs = split_directories (full_progname, &prog_num);
318 free (full_progname);
319 if (prog_dirs == NULL)
320 return NULL;
321
322 bin_dirs = split_directories (bin_prefix, &bin_num);
323 if (bin_dirs == NULL)
324 goto bailout;
325
326 /* Remove the program name from comparison of directory names. */
327 prog_num--;
328
329 /* If we are still installed in the standard location, we don't need to
330 specify relative directories. Also, if argv[0] still doesn't contain
331 any directory specifiers after the search above, then there is not much
332 we can do. */
333 if (prog_num == bin_num)
334 {
335 for (i = 0; i < bin_num; i++)
336 {
337 if (strcmp (prog_dirs[i], bin_dirs[i]) != 0)
338 break;
339 }
340
341 if (prog_num <= 0 || i == bin_num)
342 goto bailout;
343 }
344
345 prefix_dirs = split_directories (prefix, &prefix_num);
346 if (prefix_dirs == NULL)
347 goto bailout;
348
349 /* Find how many directories are in common between bin_prefix & prefix. */
350 n = (prefix_num < bin_num) ? prefix_num : bin_num;
351 for (common = 0; common < n; common++)
352 {
353 if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0)
354 break;
355 }
356
357 /* If there are no common directories, there can be no relative prefix. */
358 if (common == 0)
359 goto bailout;
360
361 /* Two passes: first figure out the size of the result string, and
362 then construct it. */
363 needed_len = 0;
364 for (i = 0; i < prog_num; i++)
365 needed_len += strlen (prog_dirs[i]);
366 needed_len += sizeof (DIR_UP) * (bin_num - common);
367 for (i = common; i < prefix_num; i++)
368 needed_len += strlen (prefix_dirs[i]);
369 needed_len += 1; /* Trailing NUL. */
370
371 ret = (char *) malloc (needed_len);
372 if (ret == NULL)
373 goto bailout;
374
375 /* Build up the pathnames in argv[0]. */
376 *ret = '\0';
377 for (i = 0; i < prog_num; i++)
378 strcat (ret, prog_dirs[i]);
379
380 /* Now build up the ..'s. */
381 ptr = ret + strlen(ret);
382 for (i = common; i < bin_num; i++)
383 {
384 strcpy (ptr, DIR_UP);
385 ptr += sizeof (DIR_UP) - 1;
386 *(ptr++) = DIR_SEPARATOR;
387 }
388 *ptr = '\0';
389
390 /* Put in directories to move over to prefix. */
391 for (i = common; i < prefix_num; i++)
392 strcat (ret, prefix_dirs[i]);
393
394 bailout:
395 free_split_directories (prog_dirs);
396 free_split_directories (bin_dirs);
397 free_split_directories (prefix_dirs);
398
399 return ret;
400 }
401
402
403 /* Do the full job, including symlink resolution.
404 This path will find files installed in the same place as the
405 program even when a soft link has been made to the program
406 from somwhere else. */
407
408 char *
make_relative_prefix(const char * progname,const char * bin_prefix,const char * prefix)409 make_relative_prefix (const char *progname, const char *bin_prefix,
410 const char *prefix)
411 {
412 return make_relative_prefix_1 (progname, bin_prefix, prefix, 1);
413 }
414
415 /* Make the relative pathname without attempting to resolve any links.
416 '..' etc may also be left in the pathname.
417 This will find the files the user meant the program to find if the
418 installation is patched together with soft links. */
419
420 char *
make_relative_prefix_ignore_links(const char * progname,const char * bin_prefix,const char * prefix)421 make_relative_prefix_ignore_links (const char *progname,
422 const char *bin_prefix,
423 const char *prefix)
424 {
425 return make_relative_prefix_1 (progname, bin_prefix, prefix, 0);
426 }
427
428