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 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 #include <limits.h> 39 #include <errno.h> 40 #include <inttypes.h> 41 #include <stdlib.h> 42 #include <stdio.h> 43 #include "arith.h" 44 #include "arith_yacc.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 int letcmd(int, char **); 88 89 static __dead2 void yyerror(const char *s) 90 { 91 error("arithmetic expression: %s: \"%s\"", s, arith_startbuf); 92 /* NOTREACHED */ 93 } 94 95 static arith_t 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 arith_prec(int op) 114 { 115 return prec[op - ARITH_BINOP_MIN]; 116 } 117 118 static inline int higher_prec(int op1, int op2) 119 { 120 return arith_prec(op1) < arith_prec(op2); 121 } 122 123 static arith_t do_binop(int op, arith_t a, arith_t b) 124 { 125 126 switch (op) { 127 default: 128 case ARITH_REM: 129 case ARITH_DIV: 130 if (!b) 131 yyerror("division by zero"); 132 if (a == ARITH_MIN && b == -1) 133 yyerror("divide error"); 134 return op == ARITH_REM ? a % b : a / b; 135 case ARITH_MUL: 136 return (uintmax_t)a * (uintmax_t)b; 137 case ARITH_ADD: 138 return (uintmax_t)a + (uintmax_t)b; 139 case ARITH_SUB: 140 return (uintmax_t)a - (uintmax_t)b; 141 case ARITH_LSHIFT: 142 return (uintmax_t)a << (b & (sizeof(uintmax_t) * CHAR_BIT - 1)); 143 case ARITH_RSHIFT: 144 return a >> (b & (sizeof(uintmax_t) * CHAR_BIT - 1)); 145 case ARITH_LT: 146 return a < b; 147 case ARITH_LE: 148 return a <= b; 149 case ARITH_GT: 150 return a > b; 151 case ARITH_GE: 152 return a >= b; 153 case ARITH_EQ: 154 return a == b; 155 case ARITH_NE: 156 return a != b; 157 case ARITH_BAND: 158 return a & b; 159 case ARITH_BXOR: 160 return a ^ b; 161 case ARITH_BOR: 162 return a | b; 163 } 164 } 165 166 static arith_t assignment(int var, int noeval); 167 168 static arith_t primary(int token, union yystype *val, int op, int noeval) 169 { 170 arith_t result; 171 172 again: 173 switch (token) { 174 case ARITH_LPAREN: 175 result = assignment(op, noeval); 176 if (last_token != ARITH_RPAREN) 177 yyerror("expecting ')'"); 178 last_token = yylex(); 179 return result; 180 case ARITH_NUM: 181 last_token = op; 182 return val->val; 183 case ARITH_VAR: 184 last_token = op; 185 return noeval ? val->val : arith_lookupvarint(val->name); 186 case ARITH_ADD: 187 token = op; 188 *val = yylval; 189 op = yylex(); 190 goto again; 191 case ARITH_SUB: 192 *val = yylval; 193 return -primary(op, val, yylex(), noeval); 194 case ARITH_NOT: 195 *val = yylval; 196 return !primary(op, val, yylex(), noeval); 197 case ARITH_BNOT: 198 *val = yylval; 199 return ~primary(op, val, yylex(), noeval); 200 default: 201 yyerror("expecting primary"); 202 } 203 } 204 205 static arith_t binop2(arith_t a, int op, int precedence, int noeval) 206 { 207 for (;;) { 208 union yystype val; 209 arith_t b; 210 int op2; 211 int token; 212 213 token = yylex(); 214 val = yylval; 215 216 b = primary(token, &val, yylex(), noeval); 217 218 op2 = last_token; 219 if (op2 >= ARITH_BINOP_MIN && op2 < ARITH_BINOP_MAX && 220 higher_prec(op2, op)) { 221 b = binop2(b, op2, arith_prec(op), noeval); 222 op2 = last_token; 223 } 224 225 a = noeval ? b : do_binop(op, a, b); 226 227 if (op2 < ARITH_BINOP_MIN || op2 >= ARITH_BINOP_MAX || 228 arith_prec(op2) >= precedence) 229 return a; 230 231 op = op2; 232 } 233 } 234 235 static arith_t binop(int token, union yystype *val, int op, int noeval) 236 { 237 arith_t a = primary(token, val, op, noeval); 238 239 op = last_token; 240 if (op < ARITH_BINOP_MIN || op >= ARITH_BINOP_MAX) 241 return a; 242 243 return binop2(a, op, ARITH_MAX_PREC, noeval); 244 } 245 246 static arith_t and(int token, union yystype *val, int op, int noeval) 247 { 248 arith_t a = binop(token, val, op, noeval); 249 arith_t b; 250 251 op = last_token; 252 if (op != ARITH_AND) 253 return a; 254 255 token = yylex(); 256 *val = yylval; 257 258 b = and(token, val, yylex(), noeval | !a); 259 260 return a && b; 261 } 262 263 static arith_t or(int token, union yystype *val, int op, int noeval) 264 { 265 arith_t a = and(token, val, op, noeval); 266 arith_t b; 267 268 op = last_token; 269 if (op != ARITH_OR) 270 return a; 271 272 token = yylex(); 273 *val = yylval; 274 275 b = or(token, val, yylex(), noeval | !!a); 276 277 return a || b; 278 } 279 280 static arith_t cond(int token, union yystype *val, int op, int noeval) 281 { 282 arith_t a = or(token, val, op, noeval); 283 arith_t b; 284 arith_t c; 285 286 if (last_token != ARITH_QMARK) 287 return a; 288 289 b = assignment(yylex(), noeval | !a); 290 291 if (last_token != ARITH_COLON) 292 yyerror("expecting ':'"); 293 294 token = yylex(); 295 *val = yylval; 296 297 c = cond(token, val, yylex(), noeval | !!a); 298 299 return a ? b : c; 300 } 301 302 static arith_t assignment(int var, int noeval) 303 { 304 union yystype val = yylval; 305 int op = yylex(); 306 arith_t result; 307 char sresult[DIGITS(result) + 1]; 308 309 if (var != ARITH_VAR) 310 return cond(var, &val, op, noeval); 311 312 if (op != ARITH_ASS && (op < ARITH_ASS_MIN || op >= ARITH_ASS_MAX)) 313 return cond(var, &val, op, noeval); 314 315 result = assignment(yylex(), noeval); 316 if (noeval) 317 return result; 318 319 if (op != ARITH_ASS) 320 result = do_binop(op - 11, arith_lookupvarint(val.name), result); 321 snprintf(sresult, sizeof(sresult), ARITH_FORMAT_STR, result); 322 setvar(val.name, sresult, 0); 323 return result; 324 } 325 326 arith_t arith(const char *s) 327 { 328 struct stackmark smark; 329 arith_t result; 330 331 setstackmark(&smark); 332 333 arith_buf = arith_startbuf = s; 334 335 result = assignment(yylex(), 0); 336 337 if (last_token) 338 yyerror("expecting EOF"); 339 340 popstackmark(&smark); 341 342 return result; 343 } 344 345 /* 346 * The exp(1) builtin. 347 */ 348 int 349 letcmd(int argc, char **argv) 350 { 351 const char *p; 352 char *concat; 353 char **ap; 354 arith_t i; 355 356 if (argc > 1) { 357 p = argv[1]; 358 if (argc > 2) { 359 /* 360 * Concatenate arguments. 361 */ 362 STARTSTACKSTR(concat); 363 ap = argv + 2; 364 for (;;) { 365 while (*p) 366 STPUTC(*p++, concat); 367 if ((p = *ap++) == NULL) 368 break; 369 STPUTC(' ', concat); 370 } 371 STPUTC('\0', concat); 372 p = grabstackstr(concat); 373 } 374 } else 375 p = ""; 376 377 i = arith(p); 378 379 out1fmt(ARITH_FORMAT_STR "\n", i); 380 return !i; 381 } 382