| 1 | /*- |
| 2 | * Copyright (c) 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * Copyright (c) 2007 |
| 5 | * Herbert Xu <herbert@gondor.apana.org.au>. All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to Berkeley by |
| 8 | * Kenneth Almquist. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * 3. Neither the name of the University nor the names of its contributors |
| 19 | * may be used to endorse or promote products derived from this software |
| 20 | * without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 32 | * SUCH DAMAGE. |
| 33 | * |
| 34 | * $FreeBSD: src/bin/sh/arith_yacc.c,v 1.7 2011/11/08 23:54:39 jilles Exp $ |
| 35 | */ |
| 36 | |
| 37 | #include <limits.h> |
| 38 | #include <errno.h> |
| 39 | #include <inttypes.h> |
| 40 | #include <stdlib.h> |
| 41 | #include <stdio.h> |
| 42 | #include "arith.h" |
| 43 | #include "arith_yacc.h" |
| 44 | #include "builtins.h" |
| 45 | #include "expand.h" |
| 46 | #include "shell.h" |
| 47 | #include "error.h" |
| 48 | #include "memalloc.h" |
| 49 | #include "output.h" |
| 50 | #include "options.h" |
| 51 | #include "var.h" |
| 52 | |
| 53 | #if ARITH_BOR + 11 != ARITH_BORASS || ARITH_ASS + 11 != ARITH_EQ |
| 54 | #error Arithmetic tokens are out of order. |
| 55 | #endif |
| 56 | |
| 57 | static const char *arith_startbuf; |
| 58 | |
| 59 | const char *arith_buf; |
| 60 | union yystype yylval; |
| 61 | |
| 62 | static int last_token; |
| 63 | |
| 64 | #define ARITH_PRECEDENCE(op, prec) [op - ARITH_BINOP_MIN] = prec |
| 65 | |
| 66 | static const char prec[ARITH_BINOP_MAX - ARITH_BINOP_MIN] = { |
| 67 | ARITH_PRECEDENCE(ARITH_MUL, 0), |
| 68 | ARITH_PRECEDENCE(ARITH_DIV, 0), |
| 69 | ARITH_PRECEDENCE(ARITH_REM, 0), |
| 70 | ARITH_PRECEDENCE(ARITH_ADD, 1), |
| 71 | ARITH_PRECEDENCE(ARITH_SUB, 1), |
| 72 | ARITH_PRECEDENCE(ARITH_LSHIFT, 2), |
| 73 | ARITH_PRECEDENCE(ARITH_RSHIFT, 2), |
| 74 | ARITH_PRECEDENCE(ARITH_LT, 3), |
| 75 | ARITH_PRECEDENCE(ARITH_LE, 3), |
| 76 | ARITH_PRECEDENCE(ARITH_GT, 3), |
| 77 | ARITH_PRECEDENCE(ARITH_GE, 3), |
| 78 | ARITH_PRECEDENCE(ARITH_EQ, 4), |
| 79 | ARITH_PRECEDENCE(ARITH_NE, 4), |
| 80 | ARITH_PRECEDENCE(ARITH_BAND, 5), |
| 81 | ARITH_PRECEDENCE(ARITH_BXOR, 6), |
| 82 | ARITH_PRECEDENCE(ARITH_BOR, 7), |
| 83 | }; |
| 84 | |
| 85 | #define ARITH_MAX_PREC 8 |
| 86 | |
| 87 | static __dead2 void |
| 88 | yyerror(const char *s) |
| 89 | { |
| 90 | error("arithmetic expression: %s: \"%s\"", s, arith_startbuf); |
| 91 | /* NOTREACHED */ |
| 92 | } |
| 93 | |
| 94 | static arith_t |
| 95 | arith_lookupvarint(char *varname) |
| 96 | { |
| 97 | const char *str; |
| 98 | char *p; |
| 99 | arith_t result; |
| 100 | |
| 101 | str = lookupvar(varname); |
| 102 | if (uflag && str == NULL) |
| 103 | yyerror("variable not set"); |
| 104 | if (str == NULL || *str == '\0') |
| 105 | str = "0"; |
| 106 | errno = 0; |
| 107 | result = strtoarith_t(str, &p, 0); |
| 108 | if (errno != 0 || *p != '\0') |
| 109 | yyerror("variable conversion error"); |
| 110 | return result; |
| 111 | } |
| 112 | |
| 113 | static inline int |
| 114 | arith_prec(int op) |
| 115 | { |
| 116 | return prec[op - ARITH_BINOP_MIN]; |
| 117 | } |
| 118 | |
| 119 | static inline int |
| 120 | higher_prec(int op1, int op2) |
| 121 | { |
| 122 | return arith_prec(op1) < arith_prec(op2); |
| 123 | } |
| 124 | |
| 125 | static arith_t |
| 126 | do_binop(int op, arith_t a, arith_t b) |
| 127 | { |
| 128 | |
| 129 | switch (op) { |
| 130 | default: |
| 131 | case ARITH_REM: |
| 132 | case ARITH_DIV: |
| 133 | if (!b) |
| 134 | yyerror("division by zero"); |
| 135 | if (a == ARITH_MIN && b == -1) |
| 136 | yyerror("divide error"); |
| 137 | return op == ARITH_REM ? a % b : a / b; |
| 138 | case ARITH_MUL: |
| 139 | return (uintmax_t)a * (uintmax_t)b; |
| 140 | case ARITH_ADD: |
| 141 | return (uintmax_t)a + (uintmax_t)b; |
| 142 | case ARITH_SUB: |
| 143 | return (uintmax_t)a - (uintmax_t)b; |
| 144 | case ARITH_LSHIFT: |
| 145 | return a << b; |
| 146 | case ARITH_RSHIFT: |
| 147 | return a >> b; |
| 148 | case ARITH_LT: |
| 149 | return a < b; |
| 150 | case ARITH_LE: |
| 151 | return a <= b; |
| 152 | case ARITH_GT: |
| 153 | return a > b; |
| 154 | case ARITH_GE: |
| 155 | return a >= b; |
| 156 | case ARITH_EQ: |
| 157 | return a == b; |
| 158 | case ARITH_NE: |
| 159 | return a != b; |
| 160 | case ARITH_BAND: |
| 161 | return a & b; |
| 162 | case ARITH_BXOR: |
| 163 | return a ^ b; |
| 164 | case ARITH_BOR: |
| 165 | return a | b; |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | static arith_t assignment(int var, int noeval); |
| 170 | |
| 171 | static arith_t |
| 172 | primary(int token, union yystype *val, int op, int noeval) |
| 173 | { |
| 174 | arith_t result; |
| 175 | |
| 176 | again: |
| 177 | switch (token) { |
| 178 | case ARITH_LPAREN: |
| 179 | result = assignment(op, noeval); |
| 180 | if (last_token != ARITH_RPAREN) |
| 181 | yyerror("expecting ')'"); |
| 182 | last_token = yylex(); |
| 183 | return result; |
| 184 | case ARITH_NUM: |
| 185 | last_token = op; |
| 186 | return val->val; |
| 187 | case ARITH_VAR: |
| 188 | last_token = op; |
| 189 | return noeval ? val->val : arith_lookupvarint(val->name); |
| 190 | case ARITH_ADD: |
| 191 | token = op; |
| 192 | *val = yylval; |
| 193 | op = yylex(); |
| 194 | goto again; |
| 195 | case ARITH_SUB: |
| 196 | *val = yylval; |
| 197 | return -primary(op, val, yylex(), noeval); |
| 198 | case ARITH_NOT: |
| 199 | *val = yylval; |
| 200 | return !primary(op, val, yylex(), noeval); |
| 201 | case ARITH_BNOT: |
| 202 | *val = yylval; |
| 203 | return ~primary(op, val, yylex(), noeval); |
| 204 | default: |
| 205 | yyerror("expecting primary"); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | static arith_t |
| 210 | binop2(arith_t a, int op, int precedence, int noeval) |
| 211 | { |
| 212 | for (;;) { |
| 213 | union yystype val; |
| 214 | arith_t b; |
| 215 | int op2; |
| 216 | int token; |
| 217 | |
| 218 | token = yylex(); |
| 219 | val = yylval; |
| 220 | |
| 221 | b = primary(token, &val, yylex(), noeval); |
| 222 | |
| 223 | op2 = last_token; |
| 224 | if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX && |
| 225 | higher_prec(op2, op)) { |
| 226 | b = binop2(b, op2, arith_prec(op), noeval); |
| 227 | op2 = last_token; |
| 228 | } |
| 229 | |
| 230 | a = noeval ? b : do_binop(op, a, b); |
| 231 | |
| 232 | if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX || |
| 233 | arith_prec(op2) >= precedence) |
| 234 | return a; |
| 235 | |
| 236 | op = op2; |
| 237 | } |
| 238 | } |
| 239 | |
| 240 | static arith_t |
| 241 | binop(int token, union yystype *val, int op, int noeval) |
| 242 | { |
| 243 | arith_t a = primary(token, val, op, noeval); |
| 244 | |
| 245 | op = last_token; |
| 246 | if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX) |
| 247 | return a; |
| 248 | |
| 249 | return binop2(a, op, ARITH_MAX_PREC, noeval); |
| 250 | } |
| 251 | |
| 252 | static arith_t |
| 253 | and(int token, union yystype *val, int op, int noeval) |
| 254 | { |
| 255 | arith_t a = binop(token, val, op, noeval); |
| 256 | arith_t b; |
| 257 | |
| 258 | op = last_token; |
| 259 | if (op != ARITH_AND) |
| 260 | return a; |
| 261 | |
| 262 | token = yylex(); |
| 263 | *val = yylval; |
| 264 | |
| 265 | b = and(token, val, yylex(), noeval | !a); |
| 266 | |
| 267 | return a && b; |
| 268 | } |
| 269 | |
| 270 | static arith_t |
| 271 | or(int token, union yystype *val, int op, int noeval) |
| 272 | { |
| 273 | arith_t a = and(token, val, op, noeval); |
| 274 | arith_t b; |
| 275 | |
| 276 | op = last_token; |
| 277 | if (op != ARITH_OR) |
| 278 | return a; |
| 279 | |
| 280 | token = yylex(); |
| 281 | *val = yylval; |
| 282 | |
| 283 | b = or(token, val, yylex(), noeval | !!a); |
| 284 | |
| 285 | return a || b; |
| 286 | } |
| 287 | |
| 288 | static arith_t |
| 289 | cond(int token, union yystype *val, int op, int noeval) |
| 290 | { |
| 291 | arith_t a = or(token, val, op, noeval); |
| 292 | arith_t b; |
| 293 | arith_t c; |
| 294 | |
| 295 | if (last_token != ARITH_QMARK) |
| 296 | return a; |
| 297 | |
| 298 | b = assignment(yylex(), noeval | !a); |
| 299 | |
| 300 | if (last_token != ARITH_COLON) |
| 301 | yyerror("expecting ':'"); |
| 302 | |
| 303 | token = yylex(); |
| 304 | *val = yylval; |
| 305 | |
| 306 | c = cond(token, val, yylex(), noeval | !!a); |
| 307 | |
| 308 | return a ? b : c; |
| 309 | } |
| 310 | |
| 311 | static arith_t |
| 312 | assignment(int var, int noeval) |
| 313 | { |
| 314 | union yystype val = yylval; |
| 315 | int op = yylex(); |
| 316 | arith_t result; |
| 317 | char sresult[DIGITS(result) + 1]; |
| 318 | |
| 319 | if (var != ARITH_VAR) |
| 320 | return cond(var, &val, op, noeval); |
| 321 | |
| 322 | if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX)) |
| 323 | return cond(var, &val, op, noeval); |
| 324 | |
| 325 | result = assignment(yylex(), noeval); |
| 326 | if (noeval) |
| 327 | return result; |
| 328 | |
| 329 | if (op != ARITH_ASS) |
| 330 | result = do_binop(op - 11, arith_lookupvarint(val.name), result); |
| 331 | snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result); |
| 332 | setvar(val.name, sresult, 0); |
| 333 | return result; |
| 334 | } |
| 335 | |
| 336 | arith_t |
| 337 | arith(const char *s) |
| 338 | { |
| 339 | struct stackmark smark; |
| 340 | arith_t result; |
| 341 | |
| 342 | setstackmark(&smark); |
| 343 | |
| 344 | arith_buf = arith_startbuf = s; |
| 345 | |
| 346 | result = assignment(yylex(), 0); |
| 347 | |
| 348 | if (last_token) |
| 349 | yyerror("expecting EOF"); |
| 350 | |
| 351 | popstackmark(&smark); |
| 352 | |
| 353 | return result; |
| 354 | } |
| 355 | |
| 356 | /* |
| 357 | * The exp(1) builtin. |
| 358 | */ |
| 359 | int |
| 360 | letcmd(int argc, char **argv) |
| 361 | { |
| 362 | const char *p; |
| 363 | char *concat; |
| 364 | char **ap; |
| 365 | arith_t i; |
| 366 | |
| 367 | if (argc > 1) { |
| 368 | p = argv[1]; |
| 369 | if (argc > 2) { |
| 370 | /* |
| 371 | * Concatenate arguments. |
| 372 | */ |
| 373 | STARTSTACKSTR(concat); |
| 374 | ap = argv + 2; |
| 375 | for (;;) { |
| 376 | while (*p) |
| 377 | STPUTC(*p++, concat); |
| 378 | if ((p = *ap++) == NULL) |
| 379 | break; |
| 380 | STPUTC(' ', concat); |
| 381 | } |
| 382 | STPUTC('\0', concat); |
| 383 | p = grabstackstr(concat); |
| 384 | } |
| 385 | } else |
| 386 | p = ""; |
| 387 | |
| 388 | i = arith(p); |
| 389 | |
| 390 | out1fmt(ARITH_FORMAT_STR "\n", i); |
| 391 | return !i; |
| 392 | } |
| 393 | |