1 /* Variable expansion functions for GNU Make.
2 Copyright (C) 1988-2020 Free Software Foundation, Inc.
3 This file is part of GNU Make.
5 GNU Make is free software; you can redistribute it and/or modify it under the
6 terms of the GNU General Public License as published by the Free Software
7 Foundation; either version 3 of the License, or (at your option) any later
10 GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
11 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
12 A PARTICULAR PURPOSE. See the GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License along with
15 this program. If not, see <http://www.gnu.org/licenses/>. */
27 /* Initially, any errors reported when expanding strings will be reported
28 against the file where the error appears. */
29 const floc **expanding_var = &reading_file;
31 /* The next two describe the variable output buffer.
32 This buffer is used to hold the variable-expansion of a line of the
33 makefile. It is made bigger with realloc whenever it is too small.
34 variable_buffer_length is the size currently allocated.
35 variable_buffer is the address of the buffer.
37 For efficiency, it's guaranteed that the buffer will always have
38 VARIABLE_BUFFER_ZONE extra bytes allocated. This allows you to add a few
39 extra chars without having to call a function. Note you should never use
40 these bytes unless you're _sure_ you have room (you know when the buffer
41 length was last checked. */
43 #define VARIABLE_BUFFER_ZONE 5
45 static size_t variable_buffer_length;
46 char *variable_buffer;
48 /* Subroutine of variable_expand and friends:
49 The text to add is LENGTH chars starting at STRING to the variable_buffer.
50 The text is added to the buffer at PTR, and the updated pointer into
51 the buffer is returned as the value. Thus, the value returned by
52 each call to variable_buffer_output should be the first argument to
53 the following call. */
56 variable_buffer_output (char *ptr, const char *string, size_t length)
58 size_t newlen = length + (ptr - variable_buffer);
60 if ((newlen + VARIABLE_BUFFER_ZONE) > variable_buffer_length)
62 size_t offset = ptr - variable_buffer;
63 variable_buffer_length = (newlen + 100 > 2 * variable_buffer_length
65 : 2 * variable_buffer_length);
66 variable_buffer = xrealloc (variable_buffer, variable_buffer_length);
67 ptr = variable_buffer + offset;
70 memcpy (ptr, string, length);
74 /* Return a pointer to the beginning of the variable buffer. */
77 initialize_variable_output (void)
79 /* If we don't have a variable output buffer yet, get one. */
81 if (variable_buffer == 0)
83 variable_buffer_length = 200;
84 variable_buffer = xmalloc (variable_buffer_length);
85 variable_buffer[0] = '\0';
88 return variable_buffer;
91 /* Recursively expand V. The returned string is malloc'd. */
93 static char *allocated_variable_append (const struct variable *v);
96 recursively_expand_for_file (struct variable *v, struct file *file)
100 const floc **saved_varp;
101 struct variable_set_list *save = 0;
104 /* Don't install a new location if this location is empty.
105 This can happen for command-line variables, builtin variables, etc. */
106 saved_varp = expanding_var;
107 if (v->fileinfo.filenm)
109 this_var = &v->fileinfo;
110 expanding_var = &this_var;
113 /* If we have no other file-reading context, use the variable's context. */
117 reading_file = &v->fileinfo;
123 /* Expanding V causes infinite recursion. Lose. */
124 OS (fatal, *expanding_var,
125 _("Recursive variable '%s' references itself (eventually)"),
132 save = current_variable_set_list;
133 current_variable_set_list = file->variables;
138 value = allocated_variable_append (v);
140 value = allocated_variable_expand (v->value);
147 current_variable_set_list = save;
149 expanding_var = saved_varp;
154 /* Expand a simple reference to variable NAME, which is LENGTH chars long. */
160 reference_variable (char *o, const char *name, size_t length)
165 v = lookup_variable (name, length);
168 warn_undefined (name, length);
170 /* If there's no variable by that name or it has no value, stop now. */
171 if (v == 0 || (*v->value == '\0' && !v->append))
174 value = (v->recursive ? recursively_expand (v) : v->value);
176 o = variable_buffer_output (o, value, strlen (value));
184 /* Scan STRING for variable references and expansion-function calls. Only
185 LENGTH bytes of STRING are actually scanned. If LENGTH is -1, scan until
186 a null byte is found.
188 Write the results to LINE, which must point into 'variable_buffer'. If
189 LINE is NULL, start at the beginning of the buffer.
190 Return a pointer to LINE, or to the beginning of the buffer if LINE is
194 variable_expand_string (char *line, const char *string, size_t length)
203 line = initialize_variable_output ();
205 line_offset = line - variable_buffer;
209 variable_buffer_output (o, "", 1);
210 return (variable_buffer);
213 /* We need a copy of STRING: due to eval, it's possible that it will get
214 freed as we process it (it might be the value of a variable that's reset
215 for example). Also having a nil-terminated string is handy. */
216 save = length == SIZE_MAX ? xstrdup (string) : xstrndup (string, length);
221 /* Copy all following uninteresting chars all at once to the
222 variable output buffer, and skip them. Uninteresting chars end
223 at the next $ or the end of the input. */
225 p1 = strchr (p, '$');
227 o = variable_buffer_output (o, p, p1 != 0 ? (size_t) (p1 - p) : strlen (p) + 1);
233 /* Dispatch on the char that follows the $. */
239 /* $$ or $ at the end of the string means output one $ to the
240 variable output buffer. */
241 o = variable_buffer_output (o, p1, 1);
246 /* $(...) or ${...} is the general case of substitution. */
249 char closeparen = (openparen == '(') ? ')' : '}';
251 const char *beg = p + 1;
254 const char *end, *colon;
258 if (handle_function (&op, &begp))
265 /* Is there a variable reference inside the parens or braces?
266 If so, expand it before expanding the entire reference. */
268 end = strchr (beg, closeparen);
270 /* Unterminated variable reference. */
271 O (fatal, *expanding_var, _("unterminated variable reference"));
272 p1 = lindex (beg, end, '$');
275 /* BEG now points past the opening paren or brace.
276 Count parens or braces until it is matched. */
278 for (p = beg; *p != '\0'; ++p)
282 else if (*p == closeparen && --count < 0)
285 /* If COUNT is >= 0, there were unmatched opening parens
286 or braces, so we go to the simple case of a variable name
290 abeg = expand_argument (beg, p); /* Expand the name. */
292 end = strchr (beg, '\0');
296 /* Advance P to the end of this reference. After we are
297 finished expanding this one, P will be incremented to
298 continue the scan. */
301 /* This is not a reference to a built-in function and
302 any variable references inside are now expanded.
303 Is the resultant text a substitution reference? */
305 colon = lindex (beg, end, ':');
308 /* This looks like a substitution reference: $(FOO:A=B). */
309 const char *subst_beg = colon + 1;
310 const char *subst_end = lindex (subst_beg, end, '=');
312 /* There is no = in sight. Punt on the substitution
313 reference and treat this as a variable name containing
314 a colon, in the code below. */
318 const char *replace_beg = subst_end + 1;
319 const char *replace_end = end;
321 /* Extract the variable name before the colon
322 and look up that variable. */
323 v = lookup_variable (beg, colon - beg);
325 warn_undefined (beg, colon - beg);
327 /* If the variable is not empty, perform the
329 if (v != 0 && *v->value != '\0')
331 char *pattern, *replace, *ppercent, *rpercent;
332 char *value = (v->recursive
333 ? recursively_expand (v)
336 /* Copy the pattern and the replacement. Add in an
337 extra % at the beginning to use in case there
338 isn't one in the pattern. */
339 pattern = alloca (subst_end - subst_beg + 2);
341 memcpy (pattern, subst_beg, subst_end - subst_beg);
342 pattern[subst_end - subst_beg] = '\0';
344 replace = alloca (replace_end - replace_beg + 2);
346 memcpy (replace, replace_beg,
347 replace_end - replace_beg);
348 replace[replace_end - replace_beg] = '\0';
350 /* Look for %. Set the percent pointers properly
351 based on whether we find one or not. */
352 ppercent = find_percent (pattern);
356 rpercent = find_percent (replace);
368 o = patsubst_expand_pat (o, value, pattern, replace,
378 /* This is an ordinary variable reference.
379 Look up the value of the variable. */
380 o = reference_variable (o, beg, end - beg);
390 /* A $ followed by a random char is a variable reference:
391 $a is equivalent to $(a). */
392 o = reference_variable (o, p, 1);
405 variable_buffer_output (o, "", 1);
406 return (variable_buffer + line_offset);
409 /* Scan LINE for variable references and expansion-function calls.
410 Build in 'variable_buffer' the result of expanding the references and calls.
411 Return the address of the resulting string, which is null-terminated
412 and is valid only until the next time this function is called. */
415 variable_expand (const char *line)
417 return variable_expand_string (NULL, line, SIZE_MAX);
420 /* Expand an argument for an expansion function.
421 The text starting at STR and ending at END is variable-expanded
422 into a null-terminated string that is returned as the value.
423 This is done without clobbering 'variable_buffer' or the current
424 variable-expansion that is in progress. */
427 expand_argument (const char *str, const char *end)
429 char *tmp, *alloc = NULL;
435 if (!end || *end == '\0')
436 return allocated_variable_expand (str);
438 if (end - str + 1 > 1000)
439 tmp = alloc = xmalloc (end - str + 1);
441 tmp = alloca (end - str + 1);
443 memcpy (tmp, str, end - str);
444 tmp[end - str] = '\0';
446 r = allocated_variable_expand (tmp);
453 /* Expand LINE for FILE. Error messages refer to the file and line where
454 FILE's commands were found. Expansion uses FILE's variable set list. */
457 variable_expand_for_file (const char *line, struct file *file)
460 struct variable_set_list *savev;
464 return variable_expand (line);
466 savev = current_variable_set_list;
467 current_variable_set_list = file->variables;
469 savef = reading_file;
470 if (file->cmds && file->cmds->fileinfo.filenm)
471 reading_file = &file->cmds->fileinfo;
475 result = variable_expand (line);
477 current_variable_set_list = savev;
478 reading_file = savef;
483 /* Like allocated_variable_expand, but for += target-specific variables.
484 First recursively construct the variable value from its appended parts in
485 any upper variable sets. Then expand the resulting value. */
488 variable_append (const char *name, size_t length,
489 const struct variable_set_list *set, int local)
491 const struct variable *v;
495 /* If there's nothing left to check, return the empty buffer. */
497 return initialize_variable_output ();
499 /* If this set is local and the next is not a parent, then next is local. */
500 nextlocal = local && set->next_is_parent == 0;
502 /* Try to find the variable in this variable set. */
503 v = lookup_variable_in_set (name, length, set->set);
505 /* If there isn't one, or this one is private, try the set above us. */
506 if (!v || (!local && v->private_var))
507 return variable_append (name, length, set->next, nextlocal);
509 /* If this variable type is append, first get any upper values.
510 If not, initialize the buffer. */
512 buf = variable_append (name, length, set->next, nextlocal);
514 buf = initialize_variable_output ();
516 /* Append this value to the buffer, and return it.
517 If we already have a value, first add a space. */
518 if (buf > variable_buffer)
519 buf = variable_buffer_output (buf, " ", 1);
521 /* Either expand it or copy it, depending. */
523 return variable_buffer_output (buf, v->value, strlen (v->value));
525 buf = variable_expand_string (buf, v->value, strlen (v->value));
526 return (buf + strlen (buf));
531 allocated_variable_append (const struct variable *v)
535 /* Construct the appended variable value. */
537 char *obuf = variable_buffer;
538 size_t olen = variable_buffer_length;
542 val = variable_append (v->name, strlen (v->name),
543 current_variable_set_list, 1);
544 variable_buffer_output (val, "", 1);
545 val = variable_buffer;
547 variable_buffer = obuf;
548 variable_buffer_length = olen;
553 /* Like variable_expand_for_file, but the returned string is malloc'd.
554 This function is called a lot. It wants to be efficient. */
557 allocated_variable_expand_for_file (const char *line, struct file *file)
561 char *obuf = variable_buffer;
562 size_t olen = variable_buffer_length;
566 value = variable_expand_for_file (line, file);
568 variable_buffer = obuf;
569 variable_buffer_length = olen;
574 /* Install a new variable_buffer context, returning the current one for
578 install_variable_buffer (char **bufp, size_t *lenp)
580 *bufp = variable_buffer;
581 *lenp = variable_buffer_length;
584 initialize_variable_output ();
587 /* Restore a previously-saved variable_buffer setting (free the current one).
591 restore_variable_buffer (char *buf, size_t len)
593 free (variable_buffer);
595 variable_buffer = buf;
596 variable_buffer_length = len;