scripts/kconfig/preprocess.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (C) 2018 Masahiro Yamada <yamada.masahiro@socionext.com>
   4
   5 #include <ctype.h>
   6 #include <stdarg.h>
   7 #include <stdbool.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11
  12 #include "list.h"
  13 #include "lkc.h"
  14
  15 #define ARRAY_SIZE(arr)         (sizeof(arr) / sizeof((arr)[0]))
  16
  17 static char *expand_string_with_args(const char *in, int argc, char *argv[]);
  18
  19 static void __attribute__((noreturn)) pperror(const char *format, ...)
  20 {
  21         va_list ap;
  22
  23         fprintf(stderr, "%s:%d: ", current_file->name, yylineno);
  24         va_start(ap, format);
  25         vfprintf(stderr, format, ap);
  26         va_end(ap);
  27         fprintf(stderr, "\n");
  28
  29         exit(1);
  30 }
  31
  32 /*
  33  * Environment variables
  34  */
  35 static LIST_HEAD(env_list);
  36
  37 struct env {
  38         char *name;
  39         char *value;
  40         struct list_head node;
  41 };
  42
  43 static void env_add(const char *name, const char *value)
  44 {
  45         struct env *e;
  46
  47         e = xmalloc(sizeof(*e));
  48         e->name = xstrdup(name);
  49         e->value = xstrdup(value);
  50
  51         list_add_tail(&e->node, &env_list);
  52 }
  53
  54 static void env_del(struct env *e)
  55 {
  56         list_del(&e->node);
  57         free(e->name);
  58         free(e->value);
  59         free(e);
  60 }
  61
  62 /* The returned pointer must be freed when done */
  63 static char *env_expand(const char *name)
  64 {
  65         struct env *e;
  66         const char *value;
  67
  68         if (!*name)
  69                 return NULL;
  70
  71         list_for_each_entry(e, &env_list, node) {
  72                 if (!strcmp(name, e->name))
  73                         return xstrdup(e->value);
  74         }
  75
  76         value = getenv(name);
  77         if (!value)
  78                 return NULL;
  79
  80         /*
  81          * We need to remember all referenced environment variables.
  82          * They will be written out to include/config/auto.conf.cmd
  83          */
  84         env_add(name, value);
  85
  86         return xstrdup(value);
  87 }
  88
  89 void env_write_dep(FILE *f, const char *autoconfig_name)
  90 {
  91         struct env *e, *tmp;
  92
  93         list_for_each_entry_safe(e, tmp, &env_list, node) {
  94                 fprintf(f, "ifneq \"$(%s)\" \"%s\"\n", e->name, e->value);
  95                 fprintf(f, "%s: FORCE\n", autoconfig_name);
  96                 fprintf(f, "endif\n");
  97                 env_del(e);
  98         }
  99 }
 100
 101 /*
 102  * Built-in functions
 103  */
 104 struct function {
 105         const char *name;
 106         unsigned int min_args;
 107         unsigned int max_args;
 108         char *(*func)(int argc, char *argv[]);
 109 };
 110
 111 static char *do_error_if(int argc, char *argv[])
 112 {
 113         if (!strcmp(argv[0], "y"))
 114                 pperror("%s", argv[1]);
 115
 116         return NULL;
 117 }
 118
 119 static char *do_filename(int argc, char *argv[])
 120 {
 121         return xstrdup(current_file->name);
 122 }
 123
 124 static char *do_info(int argc, char *argv[])
 125 {
 126         printf("%s\n", argv[0]);
 127
 128         return xstrdup("");
 129 }
 130
 131 static char *do_lineno(int argc, char *argv[])
 132 {
 133         char buf[16];
 134
 135         sprintf(buf, "%d", yylineno);
 136
 137         return xstrdup(buf);
 138 }
 139
 140 static char *do_shell(int argc, char *argv[])
 141 {
 142         FILE *p;
 143         char buf[256];
 144         char *cmd;
 145         size_t nread;
 146         int i;
 147
 148         cmd = argv[0];
 149
 150         p = popen(cmd, "r");
 151         if (!p) {
 152                 perror(cmd);
 153                 exit(1);
 154         }
 155
 156         nread = fread(buf, 1, sizeof(buf), p);
 157         if (nread == sizeof(buf))
 158                 nread--;
 159
 160         /* remove trailing new lines */
 161         while (nread > 0 && buf[nread - 1] == '\n')
 162                 nread--;
 163
 164         buf[nread] = 0;
 165
 166         /* replace a new line with a space */
 167         for (i = 0; i < nread; i++) {
 168                 if (buf[i] == '\n')
 169                         buf[i] = ' ';
 170         }
 171
 172         if (pclose(p) == -1) {
 173                 perror(cmd);
 174                 exit(1);
 175         }
 176
 177         return xstrdup(buf);
 178 }
 179
 180 static char *do_warning_if(int argc, char *argv[])
 181 {
 182         if (!strcmp(argv[0], "y"))
 183                 fprintf(stderr, "%s:%d: %s\n",
 184                         current_file->name, yylineno, argv[1]);
 185
 186         return xstrdup("");
 187 }
 188
 189 static const struct function function_table[] = {
 190         /* Name         MIN     MAX     Function */
 191         { "error-if",   2,      2,      do_error_if },
 192         { "filename",   0,      0,      do_filename },
 193         { "info",       1,      1,      do_info },
 194         { "lineno",     0,      0,      do_lineno },
 195         { "shell",      1,      1,      do_shell },
 196         { "warning-if", 2,      2,      do_warning_if },
 197 };
 198
 199 #define FUNCTION_MAX_ARGS               16
 200
 201 static char *function_expand(const char *name, int argc, char *argv[])
 202 {
 203         const struct function *f;
 204         int i;
 205
 206         for (i = 0; i < ARRAY_SIZE(function_table); i++) {
 207                 f = &function_table[i];
 208                 if (strcmp(f->name, name))
 209                         continue;
 210
 211                 if (argc < f->min_args)
 212                         pperror("too few function arguments passed to '%s'",
 213                                 name);
 214
 215                 if (argc > f->max_args)
 216                         pperror("too many function arguments passed to '%s'",
 217                                 name);
 218
 219                 return f->func(argc, argv);
 220         }
 221
 222         return NULL;
 223 }
 224
 225 /*
 226  * Variables (and user-defined functions)
 227  */
 228 static LIST_HEAD(variable_list);
 229
 230 struct variable {
 231         char *name;
 232         char *value;
 233         enum variable_flavor flavor;
 234         int exp_count;
 235         struct list_head node;
 236 };
 237
 238 static struct variable *variable_lookup(const char *name)
 239 {
 240         struct variable *v;
 241
 242         list_for_each_entry(v, &variable_list, node) {
 243                 if (!strcmp(name, v->name))
 244                         return v;
 245         }
 246
 247         return NULL;
 248 }
 249
 250 static char *variable_expand(const char *name, int argc, char *argv[])
 251 {
 252         struct variable *v;
 253         char *res;
 254
 255         v = variable_lookup(name);
 256         if (!v)
 257                 return NULL;
 258
 259         if (argc == 0 && v->exp_count)
 260                 pperror("Recursive variable '%s' references itself (eventually)",
 261                         name);
 262
 263         if (v->exp_count > 1000)
 264                 pperror("Too deep recursive expansion");
 265
 266         v->exp_count++;
 267
 268         if (v->flavor == VAR_RECURSIVE)
 269                 res = expand_string_with_args(v->value, argc, argv);
 270         else
 271                 res = xstrdup(v->value);
 272
 273         v->exp_count--;
 274
 275         return res;
 276 }
 277
 278 void variable_add(const char *name, const char *value,
 279                   enum variable_flavor flavor)
 280 {
 281         struct variable *v;
 282         char *new_value;
 283         bool append = false;
 284
 285         v = variable_lookup(name);
 286         if (v) {
 287                 /* For defined variables, += inherits the existing flavor */
 288                 if (flavor == VAR_APPEND) {
 289                         flavor = v->flavor;
 290                         append = true;
 291                 } else {
 292                         free(v->value);
 293                 }
 294         } else {
 295                 /* For undefined variables, += assumes the recursive flavor */
 296                 if (flavor == VAR_APPEND)
 297                         flavor = VAR_RECURSIVE;
 298
 299                 v = xmalloc(sizeof(*v));
 300                 v->name = xstrdup(name);
 301                 v->exp_count = 0;
 302                 list_add_tail(&v->node, &variable_list);
 303         }
 304
 305         v->flavor = flavor;
 306
 307         if (flavor == VAR_SIMPLE)
 308                 new_value = expand_string(value);
 309         else
 310                 new_value = xstrdup(value);
 311
 312         if (append) {
 313                 v->value = xrealloc(v->value,
 314                                     strlen(v->value) + strlen(new_value) + 2);
 315                 strcat(v->value, " ");
 316                 strcat(v->value, new_value);
 317                 free(new_value);
 318         } else {
 319                 v->value = new_value;
 320         }
 321 }
 322
 323 static void variable_del(struct variable *v)
 324 {
 325         list_del(&v->node);
 326         free(v->name);
 327         free(v->value);
 328         free(v);
 329 }
 330
 331 void variable_all_del(void)
 332 {
 333         struct variable *v, *tmp;
 334
 335         list_for_each_entry_safe(v, tmp, &variable_list, node)
 336                 variable_del(v);
 337 }
 338
 339 /*
 340  * Evaluate a clause with arguments.  argc/argv are arguments from the upper
 341  * function call.
 342  *
 343  * Returned string must be freed when done
 344  */
 345 static char *eval_clause(const char *str, size_t len, int argc, char *argv[])
 346 {
 347         char *tmp, *name, *res, *endptr, *prev, *p;
 348         int new_argc = 0;
 349         char *new_argv[FUNCTION_MAX_ARGS];
 350         int nest = 0;
 351         int i;
 352         unsigned long n;
 353
 354         tmp = xstrndup(str, len);
 355
 356         /*
 357          * If variable name is '1', '2', etc.  It is generally an argument
 358          * from a user-function call (i.e. local-scope variable).  If not
 359          * available, then look-up global-scope variables.
 360          */
 361         n = strtoul(tmp, &endptr, 10);
 362         if (!*endptr && n > 0 && n <= argc) {
 363                 res = xstrdup(argv[n - 1]);
 364                 goto free_tmp;
 365         }
 366
 367         prev = p = tmp;
 368
 369         /*
 370          * Split into tokens
 371          * The function name and arguments are separated by a comma.
 372          * For example, if the function call is like this:
 373          *   $(foo,$(x),$(y))
 374          *
 375          * The input string for this helper should be:
 376          *   foo,$(x),$(y)
 377          *
 378          * and split into:
 379          *   new_argv[0] = 'foo'
 380          *   new_argv[1] = '$(x)'
 381          *   new_argv[2] = '$(y)'
 382          */
 383         while (*p) {
 384                 if (nest == 0 && *p == ',') {
 385                         *p = 0;
 386                         if (new_argc >= FUNCTION_MAX_ARGS)
 387                                 pperror("too many function arguments");
 388                         new_argv[new_argc++] = prev;
 389                         prev = p + 1;
 390                 } else if (*p == '(') {
 391                         nest++;
 392                 } else if (*p == ')') {
 393                         nest--;
 394                 }
 395
 396                 p++;
 397         }
 398         new_argv[new_argc++] = prev;
 399
 400         /*
 401          * Shift arguments
 402          * new_argv[0] represents a function name or a variable name.  Put it
 403          * into 'name', then shift the rest of the arguments.  This simplifies
 404          * 'const' handling.
 405          */
 406         name = expand_string_with_args(new_argv[0], argc, argv);
 407         new_argc--;
 408         for (i = 0; i < new_argc; i++)
 409                 new_argv[i] = expand_string_with_args(new_argv[i + 1],
 410                                                       argc, argv);
 411
 412         /* Search for variables */
 413         res = variable_expand(name, new_argc, new_argv);
 414         if (res)
 415                 goto free;
 416
 417         /* Look for built-in functions */
 418         res = function_expand(name, new_argc, new_argv);
 419         if (res)
 420                 goto free;
 421
 422         /* Last, try environment variable */
 423         if (new_argc == 0) {
 424                 res = env_expand(name);
 425                 if (res)
 426                         goto free;
 427         }
 428
 429         res = xstrdup("");
 430 free:
 431         for (i = 0; i < new_argc; i++)
 432                 free(new_argv[i]);
 433         free(name);
 434 free_tmp:
 435         free(tmp);
 436
 437         return res;
 438 }
 439
 440 /*
 441  * Expand a string that follows '$'
 442  *
 443  * For example, if the input string is
 444  *     ($(FOO)$($(BAR)))$(BAZ)
 445  * this helper evaluates
 446  *     $($(FOO)$($(BAR)))
 447  * and returns a new string containing the expansion (note that the string is
 448  * recursively expanded), also advancing 'str' to point to the next character
 449  * after the corresponding closing parenthesis, in this case, *str will be
 450  *     $(BAR)
 451  */
 452 static char *expand_dollar_with_args(const char **str, int argc, char *argv[])
 453 {
 454         const char *p = *str;
 455         const char *q;
 456         int nest = 0;
 457
 458         /*
 459          * In Kconfig, variable/function references always start with "$(".
 460          * Neither single-letter variables as in $A nor curly braces as in ${CC}
 461          * are supported.  '$' not followed by '(' loses its special meaning.
 462          */
 463         if (*p != '(') {
 464                 *str = p;
 465                 return xstrdup("$");
 466         }
 467
 468         p++;
 469         q = p;
 470         while (*q) {
 471                 if (*q == '(') {
 472                         nest++;
 473                 } else if (*q == ')') {
 474                         if (nest-- == 0)
 475                                 break;
 476                 }
 477                 q++;
 478         }
 479
 480         if (!*q)
 481                 pperror("unterminated reference to '%s': missing ')'", p);
 482
 483         /* Advance 'str' to after the expanded initial portion of the string */
 484         *str = q + 1;
 485
 486         return eval_clause(p, q - p, argc, argv);
 487 }
 488
 489 char *expand_dollar(const char **str)
 490 {
 491         return expand_dollar_with_args(str, 0, NULL);
 492 }
 493
 494 static char *__expand_string(const char **str, bool (*is_end)(char c),
 495                              int argc, char *argv[])
 496 {
 497         const char *in, *p;
 498         char *expansion, *out;
 499         size_t in_len, out_len;
 500
 501         out = xmalloc(1);
 502         *out = 0;
 503         out_len = 1;
 504
 505         p = in = *str;
 506
 507         while (1) {
 508                 if (*p == '$') {
 509                         in_len = p - in;
 510                         p++;
 511                         expansion = expand_dollar_with_args(&p, argc, argv);
 512                         out_len += in_len + strlen(expansion);
 513                         out = xrealloc(out, out_len);
 514                         strncat(out, in, in_len);
 515                         strcat(out, expansion);
 516                         free(expansion);
 517                         in = p;
 518                         continue;
 519                 }
 520
 521                 if (is_end(*p))
 522                         break;
 523
 524                 p++;
 525         }
 526
 527         in_len = p - in;
 528         out_len += in_len;
 529         out = xrealloc(out, out_len);
 530         strncat(out, in, in_len);
 531
 532         /* Advance 'str' to the end character */
 533         *str = p;
 534
 535         return out;
 536 }
 537
 538 static bool is_end_of_str(char c)
 539 {
 540         return !c;
 541 }
 542
 543 /*
 544  * Expand variables and functions in the given string.  Undefined variables
 545  * expand to an empty string.
 546  * The returned string must be freed when done.
 547  */
 548 static char *expand_string_with_args(const char *in, int argc, char *argv[])
 549 {
 550         return __expand_string(&in, is_end_of_str, argc, argv);
 551 }
 552
 553 char *expand_string(const char *in)
 554 {
 555         return expand_string_with_args(in, 0, NULL);
 556 }
 557
 558 static bool is_end_of_token(char c)
 559 {
 560         return !(isalnum(c) || c == '_' || c == '-');
 561 }
 562
 563 /*
 564  * Expand variables in a token.  The parsing stops when a token separater
 565  * (in most cases, it is a whitespace) is encountered.  'str' is updated to
 566  * point to the next character.
 567  *
 568  * The returned string must be freed when done.
 569  */
 570 char *expand_one_token(const char **str)
 571 {
 572         return __expand_string(str, is_end_of_token, 0, NULL);
 573 }