bin/sh/alias.c

   1 /*      $NetBSD: alias.c,v 1.11 2002/11/24 22:35:38 christos 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 1.11 2002/11/24 22:35:38 christos 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 "var.h"
  54
  55 #define ATABSIZE 39
  56
  57 struct alias *atab[ATABSIZE];
  58
  59 STATIC void setalias(char *, char *);
  60 STATIC int unalias(char *);
  61 STATIC struct alias **hashalias(char *);
  62
  63 STATIC
  64 void
  65 setalias(char *name, char *val)
  66 {
  67         struct alias *ap, **app;
  68
  69         app = hashalias(name);
  70         for (ap = *app; ap; ap = ap->next) {
  71                 if (equal(name, ap->name)) {
  72                         INTOFF;
  73                         ckfree(ap->val);
  74                         ap->val = savestr(val);
  75                         INTON;
  76                         return;
  77                 }
  78         }
  79         /* not found */
  80         INTOFF;
  81         ap = ckmalloc(sizeof (struct alias));
  82         ap->name = savestr(name);
  83         /*
  84          * XXX - HACK: in order that the parser will not finish reading the
  85          * alias value off the input before processing the next alias, we
  86          * dummy up an extra space at the end of the alias.  This is a crock
  87          * and should be re-thought.  The idea (if you feel inclined to help)
  88          * is to avoid alias recursions.  The mechanism used is: when
  89          * expanding an alias, the value of the alias is pushed back on the
  90          * input as a string and a pointer to the alias is stored with the
  91          * string.  The alias is marked as being in use.  When the input
  92          * routine finishes reading the string, it markes the alias not
  93          * in use.  The problem is synchronization with the parser.  Since
  94          * it reads ahead, the alias is marked not in use before the
  95          * resulting token(s) is next checked for further alias sub.  The
  96          * H A C K is that we add a little fluff after the alias value
  97          * so that the string will not be exhausted.  This is a good
  98          * idea ------- ***NOT***
  99          */
 100 #ifdef notyet
 101         ap->val = savestr(val);
 102 #else /* hack */
 103         {
 104         int len = strlen(val);
 105         ap->val = ckmalloc(len + 2);
 106         memcpy(ap->val, val, len);
 107         ap->val[len] = ' ';     /* fluff */
 108         ap->val[len+1] = '\0';
 109         }
 110 #endif
 111         ap->next = *app;
 112         *app = ap;
 113         INTON;
 114 }
 115
 116 STATIC int
 117 unalias(char *name)
 118 {
 119         struct alias *ap, **app;
 120
 121         app = hashalias(name);
 122
 123         for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
 124                 if (equal(name, ap->name)) {
 125                         /*
 126                          * if the alias is currently in use (i.e. its
 127                          * buffer is being used by the input routine) we
 128                          * just null out the name instead of freeing it.
 129                          * We could clear it out later, but this situation
 130                          * is so rare that it hardly seems worth it.
 131                          */
 132                         if (ap->flag & ALIASINUSE)
 133                                 *ap->name = '\0';
 134                         else {
 135                                 INTOFF;
 136                                 *app = ap->next;
 137                                 ckfree(ap->name);
 138                                 ckfree(ap->val);
 139                                 ckfree(ap);
 140                                 INTON;
 141                         }
 142                         return (0);
 143                 }
 144         }
 145
 146         return (1);
 147 }
 148
 149 #ifdef mkinit
 150 MKINIT void rmaliases(void);
 151
 152 SHELLPROC {
 153         rmaliases();
 154 }
 155 #endif
 156
 157 void
 158 rmaliases(void)
 159 {
 160         struct alias *ap, *tmp;
 161         int i;
 162
 163         INTOFF;
 164         for (i = 0; i < ATABSIZE; i++) {
 165                 ap = atab[i];
 166                 atab[i] = NULL;
 167                 while (ap) {
 168                         ckfree(ap->name);
 169                         ckfree(ap->val);
 170                         tmp = ap;
 171                         ap = ap->next;
 172                         ckfree(tmp);
 173                 }
 174         }
 175         INTON;
 176 }
 177
 178 struct alias *
 179 lookupalias(char *name, int check)
 180 {
 181         struct alias *ap = *hashalias(name);
 182
 183         for (; ap; ap = ap->next) {
 184                 if (equal(name, ap->name)) {
 185                         if (check && (ap->flag & ALIASINUSE))
 186                                 return (NULL);
 187                         return (ap);
 188                 }
 189         }
 190
 191         return (NULL);
 192 }
 193
 194 char *
 195 get_alias_text(char *name)
 196 {
 197         struct alias *ap;
 198
 199         ap = lookupalias(name, 0);
 200         if (ap == NULL)
 201                 return NULL;
 202         return ap->val;
 203 }
 204
 205 /*
 206  * TODO - sort output
 207  */
 208 int
 209 aliascmd(int argc, char **argv)
 210 {
 211         char *n, *v;
 212         int ret = 0;
 213         struct alias *ap;
 214
 215         if (argc == 1) {
 216                 int i;
 217
 218                 for (i = 0; i < ATABSIZE; i++)
 219                         for (ap = atab[i]; ap; ap = ap->next) {
 220                                 if (*ap->name != '\0') {
 221                                         out1fmt("alias %s=", ap->name);
 222                                         print_quoted(ap->val);
 223                                         out1c('\n');
 224                                 }
 225                         }
 226                 return (0);
 227         }
 228         while ((n = *++argv) != NULL) {
 229                 if ((v = strchr(n+1, '=')) == NULL) { /* n+1: funny ksh stuff */
 230                         if ((ap = lookupalias(n, 0)) == NULL) {
 231                                 outfmt(out2, "alias: %s not found\n", n);
 232                                 ret = 1;
 233                         } else {
 234                                 out1fmt("alias %s=", n);
 235                                 print_quoted(ap->val);
 236                                 out1c('\n');
 237                         }
 238                 } else {
 239                         *v++ = '\0';
 240                         setalias(n, v);
 241                 }
 242         }
 243
 244         return (ret);
 245 }
 246
 247 int
 248 unaliascmd(int argc, char **argv)
 249 {
 250         int i;
 251
 252         while ((i = nextopt("a")) != '\0') {
 253                 if (i == 'a') {
 254                         rmaliases();
 255                         return (0);
 256                 }
 257         }
 258         for (i = 0; *argptr; argptr++)
 259                 i = unalias(*argptr);
 260
 261         return (i);
 262 }
 263
 264 STATIC struct alias **
 265 hashalias(char *p)
 266 {
 267         unsigned int hashval;
 268
 269         hashval = *p << 4;
 270         while (*p)
 271                 hashval+= *p++;
 272         return &atab[hashval % ATABSIZE];
 273 }