1 /* Copyright (C) 2002-2020 Free Software Foundation, Inc. 2 Contributed by Andy Vaught 3 4 This file is part of the GNU Fortran runtime library (libgfortran). 5 6 Libgfortran is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 Libgfortran is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 Under Section 7 of GPL version 3, you are granted additional 17 permissions described in the GCC Runtime Library Exception, version 18 3.1, as published by the Free Software Foundation. 19 20 You should have received a copy of the GNU General Public License and 21 a copy of the GCC Runtime Library Exception along with this program; 22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 <http://www.gnu.org/licenses/>. */ 24 25 #include "libgfortran.h" 26 27 #include <string.h> 28 #include <strings.h> 29 #include <ctype.h> 30 31 #ifdef HAVE_UNISTD_H 32 #include <unistd.h> 33 #endif 34 35 36 /* Implementation of secure_getenv() for targets where it is not 37 provided. */ 38 39 #ifdef FALLBACK_SECURE_GETENV 40 41 #if SUPPORTS_WEAKREF && defined(HAVE___SECURE_GETENV) 42 static char* weak_secure_getenv (const char*) 43 __attribute__((__weakref__("__secure_getenv"))); 44 #endif 45 46 char * 47 secure_getenv (const char *name) 48 { 49 #if SUPPORTS_WEAKREF && defined(HAVE___SECURE_GETENV) 50 if (weak_secure_getenv) 51 return weak_secure_getenv (name); 52 #endif 53 54 if ((getuid () == geteuid ()) && (getgid () == getegid ())) 55 return getenv (name); 56 else 57 return NULL; 58 } 59 #endif 60 61 62 63 /* Examine the environment for controlling aspects of the program's 64 execution. Our philosophy here that the environment should not prevent 65 the program from running, so any invalid value will be ignored. */ 66 67 68 options_t options; 69 70 typedef struct variable 71 { 72 const char *name; 73 int default_value; 74 int *var; 75 void (*init) (struct variable *); 76 } 77 variable; 78 79 static void init_unformatted (variable *); 80 81 82 /* Initialize an integer environment variable. */ 83 84 static void 85 init_integer (variable * v) 86 { 87 char *p, *q; 88 89 p = getenv (v->name); 90 if (p == NULL) 91 return; 92 93 for (q = p; *q; q++) 94 if (!isdigit (*q) && (p != q || *q != '-')) 95 return; 96 97 *v->var = atoi (p); 98 } 99 100 101 /* Initialize a boolean environment variable. We only look at the first 102 letter of the value. */ 103 104 static void 105 init_boolean (variable * v) 106 { 107 char *p; 108 109 p = getenv (v->name); 110 if (p == NULL) 111 return; 112 113 if (*p == '1' || *p == 'Y' || *p == 'y') 114 *v->var = 1; 115 else if (*p == '0' || *p == 'N' || *p == 'n') 116 *v->var = 0; 117 } 118 119 120 /* Initialize a list output separator. It may contain any number of spaces 121 and at most one comma. */ 122 123 static void 124 init_sep (variable * v) 125 { 126 int seen_comma; 127 char *p; 128 129 p = getenv (v->name); 130 if (p == NULL) 131 goto set_default; 132 133 options.separator = p; 134 options.separator_len = strlen (p); 135 136 /* Make sure the separator is valid */ 137 138 if (options.separator_len == 0) 139 goto set_default; 140 seen_comma = 0; 141 142 while (*p) 143 { 144 if (*p == ',') 145 { 146 if (seen_comma) 147 goto set_default; 148 seen_comma = 1; 149 p++; 150 continue; 151 } 152 153 if (*p++ != ' ') 154 goto set_default; 155 } 156 157 return; 158 159 set_default: 160 options.separator = " "; 161 options.separator_len = 1; 162 } 163 164 165 static variable variable_table[] = { 166 167 /* Unit number that will be preconnected to standard input */ 168 { "GFORTRAN_STDIN_UNIT", GFC_STDIN_UNIT_NUMBER, &options.stdin_unit, 169 init_integer }, 170 171 /* Unit number that will be preconnected to standard output */ 172 { "GFORTRAN_STDOUT_UNIT", GFC_STDOUT_UNIT_NUMBER, &options.stdout_unit, 173 init_integer }, 174 175 /* Unit number that will be preconnected to standard error */ 176 { "GFORTRAN_STDERR_UNIT", GFC_STDERR_UNIT_NUMBER, &options.stderr_unit, 177 init_integer }, 178 179 /* If TRUE, all output will be unbuffered */ 180 { "GFORTRAN_UNBUFFERED_ALL", 0, &options.all_unbuffered, init_boolean }, 181 182 /* If TRUE, output to preconnected units will be unbuffered */ 183 { "GFORTRAN_UNBUFFERED_PRECONNECTED", 0, &options.unbuffered_preconnected, 184 init_boolean }, 185 186 /* Whether to print filename and line number on runtime error */ 187 { "GFORTRAN_SHOW_LOCUS", 1, &options.locus, init_boolean }, 188 189 /* Print optional plus signs in numbers where permitted */ 190 { "GFORTRAN_OPTIONAL_PLUS", 0, &options.optional_plus, init_boolean }, 191 192 /* Separator to use when writing list output */ 193 { "GFORTRAN_LIST_SEPARATOR", 0, NULL, init_sep }, 194 195 /* Set the default data conversion for unformatted I/O */ 196 { "GFORTRAN_CONVERT_UNIT", 0, 0, init_unformatted }, 197 198 /* Print out a backtrace if possible on runtime error */ 199 { "GFORTRAN_ERROR_BACKTRACE", -1, &options.backtrace, init_boolean }, 200 201 /* Buffer size for unformatted files. */ 202 { "GFORTRAN_UNFORMATTED_BUFFER_SIZE", 0, &options.unformatted_buffer_size, 203 init_integer }, 204 205 /* Buffer size for formatted files. */ 206 { "GFORTRAN_FORMATTED_BUFFER_SIZE", 0, &options.formatted_buffer_size, 207 init_integer }, 208 209 { NULL, 0, NULL, NULL } 210 }; 211 212 213 /* Initialize most runtime variables from 214 * environment variables. */ 215 216 void 217 init_variables (void) 218 { 219 variable *v; 220 221 for (v = variable_table; v->name; v++) 222 { 223 if (v->var) 224 *v->var = v->default_value; 225 v->init (v); 226 } 227 } 228 229 230 /* This is the handling of the GFORTRAN_CONVERT_UNITS environment variable. 231 It is called from environ.c to parse this variable, and from 232 open.c to determine if the user specified a default for an 233 unformatted file. 234 The syntax of the environment variable is, in bison grammar: 235 236 GFORTRAN_CONVERT_UNITS: mode | mode ';' exception ; 237 mode: 'native' | 'swap' | 'big_endian' | 'little_endian' ; 238 exception: mode ':' unit_list | unit_list ; 239 unit_list: unit_spec | unit_list unit_spec ; 240 unit_spec: INTEGER | INTEGER '-' INTEGER ; 241 */ 242 243 /* Defines for the tokens. Other valid tokens are ',', ':', '-'. */ 244 245 246 #define NATIVE 257 247 #define SWAP 258 248 #define BIG 259 249 #define LITTLE 260 250 /* Some space for additional tokens later. */ 251 #define INTEGER 273 252 #define END (-1) 253 #define ILLEGAL (-2) 254 255 typedef struct 256 { 257 int unit; 258 unit_convert conv; 259 } exception_t; 260 261 262 static char *p; /* Main character pointer for parsing. */ 263 static char *lastpos; /* Auxiliary pointer, for backing up. */ 264 static int unit_num; /* The last unit number read. */ 265 static int unit_count; /* The number of units found. */ 266 static int do_count; /* Parsing is done twice - first to count the number 267 of units, then to fill in the table. This 268 variable controls what to do. */ 269 static exception_t *elist; /* The list of exceptions to the default. This is 270 sorted according to unit number. */ 271 static int n_elist; /* Number of exceptions to the default. */ 272 273 static unit_convert endian; /* Current endianness. */ 274 275 static unit_convert def; /* Default as specified (if any). */ 276 277 /* Search for a unit number, using a binary search. The 278 first argument is the unit number to search for. The second argument 279 is a pointer to an index. 280 If the unit number is found, the function returns 1, and the index 281 is that of the element. 282 If the unit number is not found, the function returns 0, and the 283 index is the one where the element would be inserted. */ 284 285 static int 286 search_unit (int unit, int *ip) 287 { 288 int low, high, mid; 289 290 if (n_elist == 0) 291 { 292 *ip = 0; 293 return 0; 294 } 295 296 low = 0; 297 high = n_elist - 1; 298 299 do 300 { 301 mid = (low + high) / 2; 302 if (unit == elist[mid].unit) 303 { 304 *ip = mid; 305 return 1; 306 } 307 else if (unit > elist[mid].unit) 308 low = mid + 1; 309 else 310 high = mid - 1; 311 } while (low <= high); 312 313 if (unit > elist[mid].unit) 314 *ip = mid + 1; 315 else 316 *ip = mid; 317 318 return 0; 319 } 320 321 /* This matches a keyword. If it is found, return the token supplied, 322 otherwise return ILLEGAL. */ 323 324 static int 325 match_word (const char *word, int tok) 326 { 327 int res; 328 329 if (strncasecmp (p, word, strlen (word)) == 0) 330 { 331 p += strlen (word); 332 res = tok; 333 } 334 else 335 res = ILLEGAL; 336 return res; 337 } 338 339 /* Match an integer and store its value in unit_num. This only works 340 if p actually points to the start of an integer. The caller has 341 to ensure this. */ 342 343 static int 344 match_integer (void) 345 { 346 unit_num = 0; 347 while (isdigit (*p)) 348 unit_num = unit_num * 10 + (*p++ - '0'); 349 return INTEGER; 350 } 351 352 /* This reads the next token from the GFORTRAN_CONVERT_UNITS variable. 353 Returned values are the different tokens. */ 354 355 static int 356 next_token (void) 357 { 358 int result; 359 360 lastpos = p; 361 switch (*p) 362 { 363 case '\0': 364 result = END; 365 break; 366 367 case ':': 368 case ',': 369 case '-': 370 case ';': 371 result = *p; 372 p++; 373 break; 374 375 case 'b': 376 case 'B': 377 result = match_word ("big_endian", BIG); 378 break; 379 380 case 'l': 381 case 'L': 382 result = match_word ("little_endian", LITTLE); 383 break; 384 385 case 'n': 386 case 'N': 387 result = match_word ("native", NATIVE); 388 break; 389 390 case 's': 391 case 'S': 392 result = match_word ("swap", SWAP); 393 break; 394 395 case '1': case '2': case '3': case '4': case '5': 396 case '6': case '7': case '8': case '9': 397 result = match_integer (); 398 break; 399 400 default: 401 result = ILLEGAL; 402 break; 403 } 404 return result; 405 } 406 407 /* Back up the last token by setting back the character pointer. */ 408 409 static void 410 push_token (void) 411 { 412 p = lastpos; 413 } 414 415 /* This is called when a unit is identified. If do_count is nonzero, 416 increment the number of units by one. If do_count is zero, 417 put the unit into the table. */ 418 419 static void 420 mark_single (int unit) 421 { 422 int i,j; 423 424 if (do_count) 425 { 426 unit_count++; 427 return; 428 } 429 if (search_unit (unit, &i)) 430 { 431 elist[i].conv = endian; 432 } 433 else 434 { 435 for (j=n_elist-1; j>=i; j--) 436 elist[j+1] = elist[j]; 437 438 n_elist += 1; 439 elist[i].unit = unit; 440 elist[i].conv = endian; 441 } 442 } 443 444 /* This is called when a unit range is identified. If do_count is 445 nonzero, increase the number of units. If do_count is zero, 446 put the unit into the table. */ 447 448 static void 449 mark_range (int unit1, int unit2) 450 { 451 int i; 452 if (do_count) 453 unit_count += abs (unit2 - unit1) + 1; 454 else 455 { 456 if (unit2 < unit1) 457 for (i=unit2; i<=unit1; i++) 458 mark_single (i); 459 else 460 for (i=unit1; i<=unit2; i++) 461 mark_single (i); 462 } 463 } 464 465 /* Parse the GFORTRAN_CONVERT_UNITS variable. This is called 466 twice, once to count the units and once to actually mark them in 467 the table. When counting, we don't check for double occurrences 468 of units. */ 469 470 static int 471 do_parse (void) 472 { 473 int tok; 474 int unit1; 475 int continue_ulist; 476 char *start; 477 478 unit_count = 0; 479 480 start = p; 481 482 /* Parse the string. First, let's look for a default. */ 483 tok = next_token (); 484 switch (tok) 485 { 486 case NATIVE: 487 endian = GFC_CONVERT_NATIVE; 488 break; 489 490 case SWAP: 491 endian = GFC_CONVERT_SWAP; 492 break; 493 494 case BIG: 495 endian = GFC_CONVERT_BIG; 496 break; 497 498 case LITTLE: 499 endian = GFC_CONVERT_LITTLE; 500 break; 501 502 case INTEGER: 503 /* A leading digit means that we are looking at an exception. 504 Reset the position to the beginning, and continue processing 505 at the exception list. */ 506 p = start; 507 goto exceptions; 508 break; 509 510 case END: 511 goto end; 512 break; 513 514 default: 515 goto error; 516 break; 517 } 518 519 tok = next_token (); 520 switch (tok) 521 { 522 case ';': 523 def = endian; 524 break; 525 526 case ':': 527 /* This isn't a default after all. Reset the position to the 528 beginning, and continue processing at the exception list. */ 529 p = start; 530 goto exceptions; 531 break; 532 533 case END: 534 def = endian; 535 goto end; 536 break; 537 538 default: 539 goto error; 540 break; 541 } 542 543 exceptions: 544 545 /* Loop over all exceptions. */ 546 while(1) 547 { 548 tok = next_token (); 549 switch (tok) 550 { 551 case NATIVE: 552 if (next_token () != ':') 553 goto error; 554 endian = GFC_CONVERT_NATIVE; 555 break; 556 557 case SWAP: 558 if (next_token () != ':') 559 goto error; 560 endian = GFC_CONVERT_SWAP; 561 break; 562 563 case LITTLE: 564 if (next_token () != ':') 565 goto error; 566 endian = GFC_CONVERT_LITTLE; 567 break; 568 569 case BIG: 570 if (next_token () != ':') 571 goto error; 572 endian = GFC_CONVERT_BIG; 573 break; 574 575 case INTEGER: 576 push_token (); 577 break; 578 579 case END: 580 goto end; 581 break; 582 583 default: 584 goto error; 585 break; 586 } 587 /* We arrive here when we want to parse a list of 588 numbers. */ 589 continue_ulist = 1; 590 do 591 { 592 tok = next_token (); 593 if (tok != INTEGER) 594 goto error; 595 596 unit1 = unit_num; 597 tok = next_token (); 598 /* The number can be followed by a - and another number, 599 which means that this is a unit range, a comma 600 or a semicolon. */ 601 if (tok == '-') 602 { 603 if (next_token () != INTEGER) 604 goto error; 605 606 mark_range (unit1, unit_num); 607 tok = next_token (); 608 if (tok == END) 609 goto end; 610 else if (tok == ';') 611 continue_ulist = 0; 612 else if (tok != ',') 613 goto error; 614 } 615 else 616 { 617 mark_single (unit1); 618 switch (tok) 619 { 620 case ';': 621 continue_ulist = 0; 622 break; 623 624 case ',': 625 break; 626 627 case END: 628 goto end; 629 break; 630 631 default: 632 goto error; 633 } 634 } 635 } while (continue_ulist); 636 } 637 end: 638 return 0; 639 error: 640 def = GFC_CONVERT_NONE; 641 return -1; 642 } 643 644 void init_unformatted (variable * v) 645 { 646 char *val; 647 val = getenv (v->name); 648 def = GFC_CONVERT_NONE; 649 n_elist = 0; 650 651 if (val == NULL) 652 return; 653 do_count = 1; 654 p = val; 655 do_parse (); 656 if (do_count <= 0) 657 { 658 n_elist = 0; 659 elist = NULL; 660 } 661 else 662 { 663 elist = xmallocarray (unit_count, sizeof (exception_t)); 664 do_count = 0; 665 p = val; 666 do_parse (); 667 } 668 } 669 670 /* Get the default conversion for for an unformatted unit. */ 671 672 unit_convert 673 get_unformatted_convert (int unit) 674 { 675 int i; 676 677 if (elist == NULL) 678 return def; 679 else if (search_unit (unit, &i)) 680 return elist[i].conv; 681 else 682 return def; 683 } 684