1 /* $NetBSD: for.c,v 1.182 2024/06/07 18:57:30 rillig Exp $ */
2
3 /*
4 * Copyright (c) 1992, The Regents of the University of California.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * Handling of .for/.endfor loops in a makefile.
34 *
35 * For loops have the form:
36 *
37 * .for <varname...> in <value...>
38 * # the body
39 * .endfor
40 *
41 * When a .for line is parsed, the following lines are copied to the body of
42 * the .for loop, until the corresponding .endfor line is reached. In this
43 * phase, the body is not yet evaluated. This also applies to any nested
44 * .for loops.
45 *
46 * After reaching the .endfor, the values from the .for line are grouped
47 * according to the number of variables. For each such group, the unexpanded
48 * body is scanned for expressions, and those that match the
49 * variable names are replaced with expressions of the form ${:U...}. After
50 * that, the body is treated like a file from an .include directive.
51 *
52 * Interface:
53 * For_Eval Evaluate the loop in the passed line.
54 *
55 * For_Run Run accumulated loop
56 */
57
58 #include "make.h"
59
60 /* "@(#)for.c 8.1 (Berkeley) 6/6/93" */
61 MAKE_RCSID("$NetBSD: for.c,v 1.182 2024/06/07 18:57:30 rillig Exp $");
62
63
64 typedef struct ForLoop {
65 Vector /* of 'char *' */ vars; /* Iteration variables */
66 SubstringWords items; /* Substitution items */
67 Buffer body; /* Unexpanded body of the loop */
68 unsigned int nextItem; /* Where to continue iterating */
69 } ForLoop;
70
71
72 static ForLoop *accumFor; /* Loop being accumulated */
73
74
75 /* See LK_FOR_BODY. */
76 static void
skip_whitespace_or_line_continuation(const char ** pp)77 skip_whitespace_or_line_continuation(const char **pp)
78 {
79 const char *p = *pp;
80 for (;;) {
81 if (ch_isspace(*p))
82 p++;
83 else if (p[0] == '\\' && p[1] == '\n')
84 p += 2;
85 else
86 break;
87 }
88 *pp = p;
89 }
90
91 static ForLoop *
ForLoop_New(void)92 ForLoop_New(void)
93 {
94 ForLoop *f = bmake_malloc(sizeof *f);
95
96 Vector_Init(&f->vars, sizeof(char *));
97 SubstringWords_Init(&f->items);
98 Buf_Init(&f->body);
99 f->nextItem = 0;
100
101 return f;
102 }
103
104 void
ForLoop_Free(ForLoop * f)105 ForLoop_Free(ForLoop *f)
106 {
107 while (f->vars.len > 0)
108 free(*(char **)Vector_Pop(&f->vars));
109 Vector_Done(&f->vars);
110
111 SubstringWords_Free(f->items);
112 Buf_Done(&f->body);
113
114 free(f);
115 }
116
117 char *
ForLoop_Details(const ForLoop * f)118 ForLoop_Details(const ForLoop *f)
119 {
120 size_t i, n;
121 const char **vars;
122 const Substring *items;
123 Buffer buf;
124
125 n = f->vars.len;
126 vars = f->vars.items;
127 assert(f->nextItem >= n);
128 items = f->items.words + f->nextItem - n;
129
130 Buf_Init(&buf);
131 for (i = 0; i < n; i++) {
132 if (i > 0)
133 Buf_AddStr(&buf, ", ");
134 Buf_AddStr(&buf, vars[i]);
135 Buf_AddStr(&buf, " = ");
136 Buf_AddRange(&buf, items[i].start, items[i].end);
137 }
138 return Buf_DoneData(&buf);
139 }
140
141 static bool
IsValidInVarname(char c)142 IsValidInVarname(char c)
143 {
144 return c != '$' && c != ':' && c != '\\' &&
145 c != '(' && c != '{' && c != ')' && c != '}';
146 }
147
148 static void
ForLoop_ParseVarnames(ForLoop * f,const char ** pp)149 ForLoop_ParseVarnames(ForLoop *f, const char **pp)
150 {
151 const char *p = *pp;
152
153 for (;;) {
154 size_t len;
155
156 cpp_skip_whitespace(&p);
157 if (*p == '\0') {
158 Parse_Error(PARSE_FATAL, "missing `in' in for");
159 while (f->vars.len > 0)
160 free(*(char **)Vector_Pop(&f->vars));
161 return;
162 }
163
164 for (len = 0; p[len] != '\0' && !ch_isspace(p[len]); len++) {
165 if (!IsValidInVarname(p[len])) {
166 Parse_Error(PARSE_FATAL,
167 "invalid character '%c' "
168 "in .for loop variable name",
169 p[len]);
170 while (f->vars.len > 0)
171 free(*(char **)Vector_Pop(&f->vars));
172 return;
173 }
174 }
175
176 if (len == 2 && p[0] == 'i' && p[1] == 'n') {
177 p += 2;
178 break;
179 }
180
181 *(char **)Vector_Push(&f->vars) = bmake_strldup(p, len);
182 p += len;
183 }
184
185 if (f->vars.len == 0) {
186 Parse_Error(PARSE_FATAL, "no iteration variables in for");
187 return;
188 }
189
190 *pp = p;
191 }
192
193 static bool
ForLoop_ParseItems(ForLoop * f,const char * p)194 ForLoop_ParseItems(ForLoop *f, const char *p)
195 {
196 char *items;
197
198 cpp_skip_whitespace(&p);
199
200 items = Var_Subst(p, SCOPE_GLOBAL, VARE_EVAL);
201 /* TODO: handle errors */
202
203 f->items = Substring_Words(items, false);
204 free(items);
205
206 if (f->items.len == 1 && Substring_IsEmpty(f->items.words[0]))
207 f->items.len = 0; /* .for var in ${:U} */
208
209 if (f->items.len % f->vars.len != 0) {
210 Parse_Error(PARSE_FATAL,
211 "Wrong number of words (%u) in .for "
212 "substitution list with %u variables",
213 (unsigned)f->items.len, (unsigned)f->vars.len);
214 return false;
215 }
216
217 return true;
218 }
219
220 static bool
IsFor(const char * p)221 IsFor(const char *p)
222 {
223 return p[0] == 'f' && p[1] == 'o' && p[2] == 'r' && ch_isspace(p[3]);
224 }
225
226 static bool
IsEndfor(const char * p)227 IsEndfor(const char *p)
228 {
229 return p[0] == 'e' && strncmp(p, "endfor", 6) == 0 &&
230 (p[6] == '\0' || ch_isspace(p[6]));
231 }
232
233 /*
234 * Evaluate the for loop in the passed line. The line looks like this:
235 * .for <varname...> in <value...>
236 *
237 * Results:
238 * 0 not a .for directive
239 * 1 found a .for directive
240 * -1 erroneous .for directive
241 */
242 int
For_Eval(const char * line)243 For_Eval(const char *line)
244 {
245 const char *p;
246 ForLoop *f;
247
248 p = line + 1; /* skip the '.' */
249 skip_whitespace_or_line_continuation(&p);
250
251 if (IsFor(p)) {
252 p += 3;
253
254 f = ForLoop_New();
255 ForLoop_ParseVarnames(f, &p);
256 if (f->vars.len > 0 && !ForLoop_ParseItems(f, p))
257 f->items.len = 0; /* don't iterate */
258
259 accumFor = f;
260 return 1;
261 } else if (IsEndfor(p)) {
262 Parse_Error(PARSE_FATAL, "for-less endfor");
263 return -1;
264 } else
265 return 0;
266 }
267
268 /*
269 * Add another line to the .for loop that is being built up.
270 * Returns false when the matching .endfor is reached.
271 */
272 bool
For_Accum(const char * line,int * forLevel)273 For_Accum(const char *line, int *forLevel)
274 {
275 const char *p = line;
276
277 if (*p == '.') {
278 p++;
279 skip_whitespace_or_line_continuation(&p);
280
281 if (IsEndfor(p)) {
282 DEBUG1(FOR, "For: end for %d\n", *forLevel);
283 if (--*forLevel == 0)
284 return false;
285 } else if (IsFor(p)) {
286 (*forLevel)++;
287 DEBUG1(FOR, "For: new loop %d\n", *forLevel);
288 }
289 }
290
291 Buf_AddStr(&accumFor->body, line);
292 Buf_AddByte(&accumFor->body, '\n');
293 return true;
294 }
295
296 /*
297 * When the body of a '.for i' loop is prepared for an iteration, each
298 * occurrence of $i in the body is replaced with ${:U...}, inserting the
299 * value of the item. If this item contains a '$', it may be the start of an
300 * expression. This expression is copied verbatim, its length is
301 * determined here, in a rather naive way, ignoring escape characters and
302 * funny delimiters in modifiers like ':S}from}to}'.
303 */
304 static size_t
ExprLen(const char * s,const char * e)305 ExprLen(const char *s, const char *e)
306 {
307 char expr_open, expr_close;
308 int depth;
309 const char *p;
310
311 if (s == e)
312 return 0; /* just escape the '$' */
313
314 expr_open = s[0];
315 if (expr_open == '(')
316 expr_close = ')';
317 else if (expr_open == '{')
318 expr_close = '}';
319 else
320 return 1; /* Single char variable */
321
322 depth = 1;
323 for (p = s + 1; p != e; p++) {
324 if (*p == expr_open)
325 depth++;
326 else if (*p == expr_close && --depth == 0)
327 return (size_t)(p + 1 - s);
328 }
329
330 /* Expression end not found, escape the $ */
331 return 0;
332 }
333
334 /*
335 * While expanding the body of a .for loop, write the item as a ${:U...}
336 * expression, escaping characters as needed. The result is later unescaped
337 * by ApplyModifier_Defined.
338 */
339 static void
AddEscaped(Buffer * cmds,Substring item,char endc)340 AddEscaped(Buffer *cmds, Substring item, char endc)
341 {
342 const char *p;
343 char ch;
344
345 for (p = item.start; p != item.end;) {
346 ch = *p;
347 if (ch == '$') {
348 size_t len = ExprLen(p + 1, item.end);
349 if (len != 0) {
350 /*
351 * XXX: Should a '\' be added here?
352 * See directive-for-escape.mk, ExprLen.
353 */
354 Buf_AddBytes(cmds, p, 1 + len);
355 p += 1 + len;
356 continue;
357 }
358 Buf_AddByte(cmds, '\\');
359 } else if (ch == ':' || ch == '\\' || ch == endc)
360 Buf_AddByte(cmds, '\\');
361 else if (ch == '\n') {
362 Parse_Error(PARSE_FATAL, "newline in .for value");
363 ch = ' '; /* prevent newline injection */
364 }
365 Buf_AddByte(cmds, ch);
366 p++;
367 }
368 }
369
370 /*
371 * While expanding the body of a .for loop, replace the variable name of an
372 * expression like ${i} or ${i:...} or $(i) or $(i:...) with ":Uvalue".
373 */
374 static void
ForLoop_SubstVarLong(ForLoop * f,unsigned int firstItem,Buffer * body,const char ** pp,char endc,const char ** inout_mark)375 ForLoop_SubstVarLong(ForLoop *f, unsigned int firstItem, Buffer *body,
376 const char **pp, char endc, const char **inout_mark)
377 {
378 size_t i;
379 const char *start = *pp;
380 const char **varnames = Vector_Get(&f->vars, 0);
381
382 for (i = 0; i < f->vars.len; i++) {
383 const char *p = start;
384
385 if (!cpp_skip_string(&p, varnames[i]))
386 continue;
387 /* XXX: why test for backslash here? */
388 if (*p != ':' && *p != endc && *p != '\\')
389 continue;
390
391 /*
392 * Found a variable match. Skip over the variable name and
393 * instead add ':U<value>' to the current body.
394 */
395 Buf_AddRange(body, *inout_mark, start);
396 Buf_AddStr(body, ":U");
397 AddEscaped(body, f->items.words[firstItem + i], endc);
398
399 *inout_mark = p;
400 *pp = p;
401 return;
402 }
403 }
404
405 /*
406 * While expanding the body of a .for loop, replace single-character
407 * expressions like $i with their ${:U...} expansion.
408 */
409 static void
ForLoop_SubstVarShort(ForLoop * f,unsigned int firstItem,Buffer * body,const char * p,const char ** inout_mark)410 ForLoop_SubstVarShort(ForLoop *f, unsigned int firstItem, Buffer *body,
411 const char *p, const char **inout_mark)
412 {
413 char ch = *p;
414 const char **vars;
415 size_t i;
416
417 /* Skip $$ and stupid ones. */
418 if (ch == '}' || ch == ')' || ch == ':' || ch == '$')
419 return;
420
421 vars = Vector_Get(&f->vars, 0);
422 for (i = 0; i < f->vars.len; i++) {
423 const char *varname = vars[i];
424 if (varname[0] == ch && varname[1] == '\0')
425 goto found;
426 }
427 return;
428
429 found:
430 Buf_AddRange(body, *inout_mark, p);
431 *inout_mark = p + 1;
432
433 /* Replace $<ch> with ${:U<value>} */
434 Buf_AddStr(body, "{:U");
435 AddEscaped(body, f->items.words[firstItem + i], '}');
436 Buf_AddByte(body, '}');
437 }
438
439 /*
440 * Compute the body for the current iteration by copying the unexpanded body,
441 * replacing the expressions for the iteration variables on the way.
442 *
443 * Using expressions ensures that the .for loop can't generate
444 * syntax, and that the later parsing will still see an expression.
445 * This code assumes that the variable with the empty name is never defined,
446 * see unit-tests/varname-empty.mk.
447 *
448 * The detection of substitutions of the loop control variables is naive.
449 * Many of the modifiers use '\$' instead of '$$' to escape '$', so it is
450 * possible to contrive a makefile where an unwanted substitution happens.
451 * See unit-tests/directive-for-escape.mk.
452 */
453 static void
ForLoop_SubstBody(ForLoop * f,unsigned int firstItem,Buffer * body)454 ForLoop_SubstBody(ForLoop *f, unsigned int firstItem, Buffer *body)
455 {
456 const char *p, *end;
457 const char *mark; /* where the last substitution left off */
458
459 Buf_Clear(body);
460
461 mark = f->body.data;
462 end = f->body.data + f->body.len;
463 for (p = mark; (p = strchr(p, '$')) != NULL;) {
464 if (p[1] == '{' || p[1] == '(') {
465 char endc = p[1] == '{' ? '}' : ')';
466 p += 2;
467 ForLoop_SubstVarLong(f, firstItem, body,
468 &p, endc, &mark);
469 } else {
470 ForLoop_SubstVarShort(f, firstItem, body,
471 p + 1, &mark);
472 p += 2;
473 }
474 }
475
476 Buf_AddRange(body, mark, end);
477 }
478
479 /*
480 * Compute the body for the current iteration by copying the unexpanded body,
481 * replacing the expressions for the iteration variables on the way.
482 */
483 bool
For_NextIteration(ForLoop * f,Buffer * body)484 For_NextIteration(ForLoop *f, Buffer *body)
485 {
486 if (f->nextItem == f->items.len)
487 return false;
488
489 f->nextItem += (unsigned int)f->vars.len;
490 ForLoop_SubstBody(f, f->nextItem - (unsigned int)f->vars.len, body);
491 if (DEBUG(FOR)) {
492 char *details = ForLoop_Details(f);
493 debug_printf("For: loop body with %s:\n%s",
494 details, body->data);
495 free(details);
496 }
497 return true;
498 }
499
500 /* Break out of the .for loop. */
501 void
For_Break(ForLoop * f)502 For_Break(ForLoop *f)
503 {
504 f->nextItem = (unsigned int)f->items.len;
505 }
506
507 /* Run the .for loop, imitating the actions of an include file. */
508 void
For_Run(unsigned headLineno,unsigned bodyReadLines)509 For_Run(unsigned headLineno, unsigned bodyReadLines)
510 {
511 Buffer buf;
512 ForLoop *f = accumFor;
513 accumFor = NULL;
514
515 if (f->items.len > 0) {
516 Buf_Init(&buf);
517 Parse_PushInput(NULL, headLineno, bodyReadLines, buf, f);
518 } else
519 ForLoop_Free(f);
520 }
521