1 /*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Cimarron D. Taylor of the University of California, Berkeley. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * $FreeBSD: src/usr.bin/find/operator.c,v 1.5.6.1 2001/05/06 09:53:22 phk Exp $ 37 * $DragonFly: src/usr.bin/find/operator.c,v 1.4 2004/07/09 19:11:20 drhodus Exp $ 38 * 39 * @(#)operator.c 8.1 (Berkeley) 6/6/93 40 */ 41 42 #include <sys/types.h> 43 44 #include <err.h> 45 #include <fts.h> 46 #include <stdio.h> 47 48 #include "find.h" 49 50 /* 51 * yanknode -- 52 * destructively removes the top from the plan 53 */ 54 /* planp: pointer to top of plan (modified) */ 55 static PLAN * 56 yanknode(PLAN **planp) 57 { 58 PLAN *node; /* top node removed from the plan */ 59 60 if ((node = (*planp)) == NULL) 61 return (NULL); 62 (*planp) = (*planp)->next; 63 node->next = NULL; 64 return (node); 65 } 66 67 /* 68 * yankexpr -- 69 * Removes one expression from the plan. This is used mainly by 70 * paren_squish. In comments below, an expression is either a 71 * simple node or a f_expr node containing a list of simple nodes. 72 */ 73 /* planp: pointer to top of plan (modified) */ 74 static PLAN * 75 yankexpr(PLAN **planp) 76 { 77 register PLAN *next; /* temp node holding subexpression results */ 78 PLAN *node; /* pointer to returned node or expression */ 79 PLAN *tail; /* pointer to tail of subplan */ 80 PLAN *subplan; /* pointer to head of ( ) expression */ 81 82 /* first pull the top node from the plan */ 83 if ((node = yanknode(planp)) == NULL) 84 return (NULL); 85 86 /* 87 * If the node is an '(' then we recursively slurp up expressions 88 * until we find its associated ')'. If it's a closing paren we 89 * just return it and unwind our recursion; all other nodes are 90 * complete expressions, so just return them. 91 */ 92 if (node->execute == f_openparen) 93 for (tail = subplan = NULL;;) { 94 if ((next = yankexpr(planp)) == NULL) 95 err(1, "(: missing closing ')'"); 96 /* 97 * If we find a closing ')' we store the collected 98 * subplan in our '(' node and convert the node to 99 * a f_expr. The ')' we found is ignored. Otherwise, 100 * we just continue to add whatever we get to our 101 * subplan. 102 */ 103 if (next->execute == f_closeparen) { 104 if (subplan == NULL) 105 errx(1, "(): empty inner expression"); 106 node->p_data[0] = subplan; 107 node->execute = f_expr; 108 break; 109 } else { 110 if (subplan == NULL) 111 tail = subplan = next; 112 else { 113 tail->next = next; 114 tail = next; 115 } 116 tail->next = NULL; 117 } 118 } 119 return (node); 120 } 121 122 /* 123 * paren_squish -- 124 * replaces "parentheisized" plans in our search plan with "expr" nodes. 125 */ 126 /* plan: plan with ( ) nodes */ 127 PLAN * 128 paren_squish(PLAN *plan) 129 { 130 register PLAN *expr; /* pointer to next expression */ 131 register PLAN *tail; /* pointer to tail of result plan */ 132 PLAN *result; /* pointer to head of result plan */ 133 134 result = tail = NULL; 135 136 /* 137 * the basic idea is to have yankexpr do all our work and just 138 * collect its results together. 139 */ 140 while ((expr = yankexpr(&plan)) != NULL) { 141 /* 142 * if we find an unclaimed ')' it means there is a missing 143 * '(' someplace. 144 */ 145 if (expr->execute == f_closeparen) 146 errx(1, "): no beginning '('"); 147 148 /* add the expression to our result plan */ 149 if (result == NULL) 150 tail = result = expr; 151 else { 152 tail->next = expr; 153 tail = expr; 154 } 155 tail->next = NULL; 156 } 157 return (result); 158 } 159 160 /* 161 * not_squish -- 162 * compresses "!" expressions in our search plan. 163 */ 164 /* plan: plan to process */ 165 PLAN * 166 not_squish(PLAN *plan) 167 { 168 register PLAN *next; /* next node being processed */ 169 register PLAN *node; /* temporary node used in f_not processing */ 170 register PLAN *tail; /* pointer to tail of result plan */ 171 PLAN *result; /* pointer to head of result plan */ 172 173 tail = result = NULL; 174 175 while ((next = yanknode(&plan))) { 176 /* 177 * if we encounter a ( expression ) then look for nots in 178 * the expr subplan. 179 */ 180 if (next->execute == f_expr) 181 next->p_data[0] = not_squish(next->p_data[0]); 182 183 /* 184 * if we encounter a not, then snag the next node and place 185 * it in the not's subplan. As an optimization we compress 186 * several not's to zero or one not. 187 */ 188 if (next->execute == f_not) { 189 int notlevel = 1; 190 191 node = yanknode(&plan); 192 while (node != NULL && node->execute == f_not) { 193 ++notlevel; 194 node = yanknode(&plan); 195 } 196 if (node == NULL) 197 errx(1, "!: no following expression"); 198 if (node->execute == f_or) 199 errx(1, "!: nothing between ! and -o"); 200 /* 201 * If we encounter ! ( expr ) then look for nots in 202 * the expr subplan. 203 */ 204 if (node->execute == f_expr) 205 node->p_data[0] = not_squish(node->p_data[0]); 206 if (notlevel % 2 != 1) 207 next = node; 208 else 209 next->p_data[0] = node; 210 } 211 212 /* add the node to our result plan */ 213 if (result == NULL) 214 tail = result = next; 215 else { 216 tail->next = next; 217 tail = next; 218 } 219 tail->next = NULL; 220 } 221 return (result); 222 } 223 224 /* 225 * or_squish -- 226 * compresses -o expressions in our search plan. 227 */ 228 /* plan: plan with ors to be squished */ 229 PLAN * 230 or_squish(PLAN *plan) 231 { 232 register PLAN *next; /* next node being processed */ 233 register PLAN *tail; /* pointer to tail of result plan */ 234 PLAN *result; /* pointer to head of result plan */ 235 236 tail = result = next = NULL; 237 238 while ((next = yanknode(&plan)) != NULL) { 239 /* 240 * if we encounter a ( expression ) then look for or's in 241 * the expr subplan. 242 */ 243 if (next->execute == f_expr) 244 next->p_data[0] = or_squish(next->p_data[0]); 245 246 /* if we encounter a not then look for or's in the subplan */ 247 if (next->execute == f_not) 248 next->p_data[0] = or_squish(next->p_data[0]); 249 250 /* 251 * if we encounter an or, then place our collected plan in the 252 * or's first subplan and then recursively collect the 253 * remaining stuff into the second subplan and return the or. 254 */ 255 if (next->execute == f_or) { 256 if (result == NULL) 257 errx(1, "-o: no expression before -o"); 258 next->p_data[0] = result; 259 next->p_data[1] = or_squish(plan); 260 if (next->p_data[1] == NULL) 261 errx(1, "-o: no expression after -o"); 262 return (next); 263 } 264 265 /* add the node to our result plan */ 266 if (result == NULL) 267 tail = result = next; 268 else { 269 tail->next = next; 270 tail = next; 271 } 272 tail->next = NULL; 273 } 274 return (result); 275 } 276