alias.c revision 1.17
1 /* $NetBSD: alias.c,v 1.17 2018/10/07 23:17:52 rillig Exp $ */ 2 3 /*- 4 * Copyright (c) 1993 5 * The Regents of the University of California. 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 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)alias.c 8.3 (Berkeley) 5/4/95"; 39 #else 40 __RCSID("$NetBSD: alias.c,v 1.17 2018/10/07 23:17:52 rillig Exp $"); 41 #endif 42 #endif /* not lint */ 43 44 #include <stdlib.h> 45 #include "shell.h" 46 #include "input.h" 47 #include "output.h" 48 #include "error.h" 49 #include "memalloc.h" 50 #include "mystring.h" 51 #include "alias.h" 52 #include "options.h" /* XXX for argptr (should remove?) */ 53 #include "builtins.h" 54 #include "var.h" 55 56 #define ATABSIZE 39 57 58 struct alias *atab[ATABSIZE]; 59 60 STATIC void setalias(char *, char *); 61 STATIC int by_name(const void *, const void *); 62 STATIC void list_aliases(void); 63 STATIC int unalias(char *); 64 STATIC struct alias **hashalias(const char *); 65 66 STATIC 67 void 68 setalias(char *name, char *val) 69 { 70 struct alias *ap, **app; 71 72 app = hashalias(name); 73 for (ap = *app; ap; ap = ap->next) { 74 if (equal(name, ap->name)) { 75 INTOFF; 76 ckfree(ap->val); 77 ap->val = savestr(val); 78 INTON; 79 return; 80 } 81 } 82 /* not found */ 83 INTOFF; 84 ap = ckmalloc(sizeof (struct alias)); 85 ap->name = savestr(name); 86 ap->flag = 0; 87 /* 88 * XXX - HACK: in order that the parser will not finish reading the 89 * alias value off the input before processing the next alias, we 90 * dummy up an extra space at the end of the alias. This is a crock 91 * and should be re-thought. The idea (if you feel inclined to help) 92 * is to avoid alias recursions. The mechanism used is: when 93 * expanding an alias, the value of the alias is pushed back on the 94 * input as a string and a pointer to the alias is stored with the 95 * string. The alias is marked as being in use. When the input 96 * routine finishes reading the string, it markes the alias not 97 * in use. The problem is synchronization with the parser. Since 98 * it reads ahead, the alias is marked not in use before the 99 * resulting token(s) is next checked for further alias sub. The 100 * H A C K is that we add a little fluff after the alias value 101 * so that the string will not be exhausted. This is a good 102 * idea ------- ***NOT*** 103 */ 104 #ifdef notyet 105 ap->val = savestr(val); 106 #else /* hack */ 107 { 108 int len = strlen(val); 109 ap->val = ckmalloc(len + 2); 110 memcpy(ap->val, val, len); 111 ap->val[len] = ' '; /* fluff */ 112 ap->val[len+1] = '\0'; 113 } 114 #endif 115 ap->next = *app; 116 *app = ap; 117 INTON; 118 } 119 120 STATIC int 121 unalias(char *name) 122 { 123 struct alias *ap, **app; 124 125 app = hashalias(name); 126 127 for (ap = *app; ap; app = &(ap->next), ap = ap->next) { 128 if (equal(name, ap->name)) { 129 /* 130 * if the alias is currently in use (i.e. its 131 * buffer is being used by the input routine) we 132 * just null out the name instead of freeing it. 133 * We could clear it out later, but this situation 134 * is so rare that it hardly seems worth it. 135 */ 136 if (ap->flag & ALIASINUSE) 137 *ap->name = '\0'; 138 else { 139 INTOFF; 140 *app = ap->next; 141 ckfree(ap->name); 142 ckfree(ap->val); 143 ckfree(ap); 144 INTON; 145 } 146 return (0); 147 } 148 } 149 150 return (1); 151 } 152 153 #ifdef mkinit 154 MKINIT void rmaliases(void); 155 156 SHELLPROC { 157 rmaliases(); 158 } 159 #endif 160 161 void 162 rmaliases(void) 163 { 164 struct alias *ap, *tmp; 165 int i; 166 167 INTOFF; 168 for (i = 0; i < ATABSIZE; i++) { 169 ap = atab[i]; 170 atab[i] = NULL; 171 while (ap) { 172 ckfree(ap->name); 173 ckfree(ap->val); 174 tmp = ap; 175 ap = ap->next; 176 ckfree(tmp); 177 } 178 } 179 INTON; 180 } 181 182 struct alias * 183 lookupalias(const char *name, int check) 184 { 185 struct alias *ap = *hashalias(name); 186 187 for (; ap; ap = ap->next) { 188 if (equal(name, ap->name)) { 189 if (check && (ap->flag & ALIASINUSE)) 190 return (NULL); 191 return (ap); 192 } 193 } 194 195 return (NULL); 196 } 197 198 const char * 199 alias_text(void *dummy __unused, const char *name) 200 { 201 struct alias *ap; 202 203 ap = lookupalias(name, 0); 204 if (ap == NULL) 205 return NULL; 206 return ap->val; 207 } 208 209 STATIC int 210 by_name(const void *a, const void *b) 211 { 212 213 return strcmp( 214 (*(const struct alias * const *)a)->name, 215 (*(const struct alias * const *)b)->name); 216 } 217 218 STATIC void 219 list_aliases(void) 220 { 221 size_t i, j, n; 222 const struct alias **aliases; 223 const struct alias *ap; 224 225 n = 0; 226 for (i = 0; i < ATABSIZE; i++) 227 for (ap = atab[i]; ap != NULL; ap = ap->next) 228 if (ap->name[0] != '\0') 229 n++; 230 231 aliases = ckmalloc(n * sizeof aliases[0]); 232 233 j = 0; 234 for (i = 0; i < ATABSIZE; i++) 235 for (ap = atab[i]; ap != NULL; ap = ap->next) 236 if (ap->name[0] != '\0') 237 aliases[j++] = ap; 238 239 qsort(aliases, n, sizeof aliases[0], by_name); 240 241 for (i = 0; i < n; i++) { 242 out1fmt("alias %s=", aliases[i]->name); 243 print_quoted(aliases[i]->val); 244 out1c('\n'); 245 } 246 247 ckfree(aliases); 248 } 249 250 int 251 aliascmd(int argc, char **argv) 252 { 253 char *n, *v; 254 int ret = 0; 255 struct alias *ap; 256 257 if (argc == 1) { 258 list_aliases(); 259 return (0); 260 } 261 262 while ((n = *++argv) != NULL) { 263 if ((v = strchr(n+1, '=')) == NULL) { /* n+1: funny ksh stuff */ 264 if ((ap = lookupalias(n, 0)) == NULL) { 265 outfmt(out2, "alias: %s not found\n", n); 266 ret = 1; 267 } else { 268 out1fmt("alias %s=", n); 269 print_quoted(ap->val); 270 out1c('\n'); 271 } 272 } else { 273 *v++ = '\0'; 274 setalias(n, v); 275 } 276 } 277 278 return (ret); 279 } 280 281 int 282 unaliascmd(int argc, char **argv) 283 { 284 int i; 285 286 while ((i = nextopt("a")) != '\0') { 287 if (i == 'a') { 288 rmaliases(); 289 return (0); 290 } 291 } 292 for (i = 0; *argptr; argptr++) 293 i = unalias(*argptr); 294 295 return (i); 296 } 297 298 STATIC struct alias ** 299 hashalias(const char *p) 300 { 301 unsigned int hashval; 302 303 hashval = *(const unsigned char *)p << 4; 304 while (*p) 305 hashval += *p++; 306 return &atab[hashval % ATABSIZE]; 307 } 308
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