source: trunk/binutils/libiberty/make-relative-prefix.c@ 2840

Last change on this file since 2840 was 607, checked in by bird, 22 years ago

Initial revision
  • Property cvs2svn:cvs-rev set to 1.1
  • Property svn:eol-style set to native
  • Property svn:executable set to *
File size: 9.7 KB
Line 
1/* Relative (relocatable) prefix support.
2 Copyright (C) 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
4
5This file is part of libiberty.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING. If not, write to the Free
19Software Foundation, 59 Temple Place - Suite 330, Boston, MA
2002111-1307, USA. */
21
22/*
23
24@deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, const char *@var{bin_prefix}, const char *@var{prefix})
25
26Given three paths @var{progname}, @var{bin_prefix}, @var{prefix},
27return 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
30portion of @var{progname}, followed by a relative pathname of the
31difference between @var{bin_prefix} and @var{prefix}.
32
33If @var{progname} does not contain any directory separators,
34@code{make_relative_prefix} will search @env{PATH} to find a program
35named @var{progname}. Also, if @var{progname} is a symbolic link,
36the symbolic link will be resolved.
37
38For 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
43The return value is normally allocated via @code{malloc}. If no
44relative 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
61#include <string.h>
62
63#include "ansidecl.h"
64#include "libiberty.h"
65
66#ifndef R_OK
67#define R_OK 4
68#define W_OK 2
69#define X_OK 1
70#endif
71
72#ifndef DIR_SEPARATOR
73# define DIR_SEPARATOR '/'
74#endif
75
76#if defined (_WIN32) || defined (__MSDOS__) \
77 || defined (__DJGPP__) || defined (__OS2__)
78# define HAVE_DOS_BASED_FILE_SYSTEM
79# define HAVE_HOST_EXECUTABLE_SUFFIX
80# define HOST_EXECUTABLE_SUFFIX ".exe"
81# ifndef DIR_SEPARATOR_2
82# define DIR_SEPARATOR_2 '\\'
83# endif
84# define PATH_SEPARATOR ';'
85#else
86# define PATH_SEPARATOR ':'
87#endif
88
89#ifndef DIR_SEPARATOR_2
90# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
91#else
92# define IS_DIR_SEPARATOR(ch) \
93 (((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
94#endif
95
96#define DIR_UP ".."
97
98static char *save_string PARAMS ((const char *, int));
99static char **split_directories PARAMS ((const char *, int *));
100static void free_split_directories PARAMS ((char **));
101
102static char *
103save_string (s, len)
104 const char *s;
105 int len;
106{
107 char *result = malloc (len + 1);
108
109 memcpy (result, s, len);
110 result[len] = 0;
111 return result;
112}
113
114/* Split a filename into component directories. */
115
116static char **
117split_directories (name, ptr_num_dirs)
118 const char *name;
119 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
203static void
204free_split_directories (dirs)
205 char **dirs;
206{
207 int i = 0;
208
209 while (dirs[i] != NULL)
210 free (dirs[i++]);
211
212 free ((char *) dirs);
213}
214
215/* Given three strings PROGNAME, BIN_PREFIX, PREFIX, return a string that gets
216 to PREFIX starting with the directory portion of PROGNAME and a relative
217 pathname of the difference between BIN_PREFIX and PREFIX.
218
219 For example, if BIN_PREFIX is /alpha/beta/gamma/gcc/delta, PREFIX is
220 /alpha/beta/gamma/omega/, and PROGNAME is /red/green/blue/gcc, then this
221 function will return /red/green/blue/../../omega/.
222
223 If no relative prefix can be found, return NULL. */
224
225char *
226make_relative_prefix (progname, bin_prefix, prefix)
227 const char *progname;
228 const char *bin_prefix;
229 const char *prefix;
230{
231 char **prog_dirs, **bin_dirs, **prefix_dirs;
232 int prog_num, bin_num, prefix_num;
233 int i, n, common;
234 int needed_len;
235 char *ret, *ptr, *full_progname = 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 if (prefixlen < 2)
252 prefixlen = 2;
253
254 nstore = (char *) alloca (prefixlen + strlen (progname) + 1);
255
256 startp = endp = temp;
257 while (1)
258 {
259 if (*endp == PATH_SEPARATOR || *endp == 0)
260 {
261 if (endp == startp)
262 {
263 nstore[0] = '.';
264 nstore[1] = DIR_SEPARATOR;
265 nstore[2] = '\0';
266 }
267 else
268 {
269 strncpy (nstore, startp, endp - startp);
270 if (! IS_DIR_SEPARATOR (endp[-1]))
271 {
272 nstore[endp - startp] = DIR_SEPARATOR;
273 nstore[endp - startp + 1] = 0;
274 }
275 else
276 nstore[endp - startp] = 0;
277 }
278 strcat (nstore, progname);
279 if (! access (nstore, X_OK)
280#ifdef HAVE_HOST_EXECUTABLE_SUFFIX
281 || ! access (strcat (nstore, HOST_EXECUTABLE_SUFFIX), X_OK)
282#endif
283 )
284 {
285 progname = nstore;
286 break;
287 }
288
289 if (*endp == 0)
290 break;
291 endp = startp = endp + 1;
292 }
293 else
294 endp++;
295 }
296 }
297 }
298
299 full_progname = lrealpath (progname);
300 if (full_progname == NULL)
301 return NULL;
302
303 prog_dirs = split_directories (full_progname, &prog_num);
304 bin_dirs = split_directories (bin_prefix, &bin_num);
305 free (full_progname);
306 if (bin_dirs == NULL || prog_dirs == NULL)
307 return NULL;
308
309 /* Remove the program name from comparison of directory names. */
310 prog_num--;
311
312 /* If we are still installed in the standard location, we don't need to
313 specify relative directories. Also, if argv[0] still doesn't contain
314 any directory specifiers after the search above, then there is not much
315 we can do. */
316 if (prog_num == bin_num)
317 {
318 for (i = 0; i < bin_num; i++)
319 {
320 if (strcmp (prog_dirs[i], bin_dirs[i]) != 0)
321 break;
322 }
323
324 if (prog_num <= 0 || i == bin_num)
325 {
326 free_split_directories (prog_dirs);
327 free_split_directories (bin_dirs);
328 prog_dirs = bin_dirs = (char **) 0;
329 return NULL;
330 }
331 }
332
333 prefix_dirs = split_directories (prefix, &prefix_num);
334 if (prefix_dirs == NULL)
335 {
336 free_split_directories (prog_dirs);
337 free_split_directories (bin_dirs);
338 return NULL;
339 }
340
341 /* Find how many directories are in common between bin_prefix & prefix. */
342 n = (prefix_num < bin_num) ? prefix_num : bin_num;
343 for (common = 0; common < n; common++)
344 {
345 if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0)
346 break;
347 }
348
349 /* If there are no common directories, there can be no relative prefix. */
350 if (common == 0)
351 {
352 free_split_directories (prog_dirs);
353 free_split_directories (bin_dirs);
354 free_split_directories (prefix_dirs);
355 return NULL;
356 }
357
358 /* Two passes: first figure out the size of the result string, and
359 then construct it. */
360 needed_len = 0;
361 for (i = 0; i < prog_num; i++)
362 needed_len += strlen (prog_dirs[i]);
363 needed_len += sizeof (DIR_UP) * (bin_num - common);
364 for (i = common; i < prefix_num; i++)
365 needed_len += strlen (prefix_dirs[i]);
366 needed_len += 1; /* Trailing NUL. */
367
368 ret = (char *) malloc (needed_len);
369 if (ret == NULL)
370 return NULL;
371
372 /* Build up the pathnames in argv[0]. */
373 *ret = '\0';
374 for (i = 0; i < prog_num; i++)
375 strcat (ret, prog_dirs[i]);
376
377 /* Now build up the ..'s. */
378 ptr = ret + strlen(ret);
379 for (i = common; i < bin_num; i++)
380 {
381 strcpy (ptr, DIR_UP);
382 ptr += sizeof (DIR_UP) - 1;
383 *(ptr++) = DIR_SEPARATOR;
384 }
385 *ptr = '\0';
386
387 /* Put in directories to move over to prefix. */
388 for (i = common; i < prefix_num; i++)
389 strcat (ret, prefix_dirs[i]);
390
391 free_split_directories (prog_dirs);
392 free_split_directories (bin_dirs);
393 free_split_directories (prefix_dirs);
394
395 return ret;
396}
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