commands/ash/alias.c

   1 /*-
   2  * Copyright (c) 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  * Kenneth Almquist.
   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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)alias.c     8.3 (Berkeley) 5/4/95";
  36 #endif
  37 #endif /* not lint */
  38 /*
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD: src/bin/sh/alias.c,v 1.18 2004/04/06 20:06:51 markm Exp $");
  41 */
  42
  43 #include <stdlib.h>
  44 #include "shell.h"
  45 #include "input.h"
  46 #include "output.h"
  47 #include "error.h"
  48 #include "memalloc.h"
  49 #include "mystring.h"
  50 #include "alias.h"
  51 #include "options.h"    /* XXX for argptr (should remove?) */
  52 #include "builtins.h"
  53
  54 #define ATABSIZE 39
  55
  56 STATIC struct alias *atab[ATABSIZE];
  57
  58 STATIC void setalias(const char *, const char *);
  59 STATIC int unalias(const char *);
  60 STATIC struct alias **hashalias(const char *);
  61
  62 STATIC
  63 void
  64 setalias(const char *name, const char *val)
  65 {
  66         struct alias *ap, **app;
  67
  68         app = hashalias(name);
  69         for (ap = *app; ap; ap = ap->next) {
  70                 if (equal(name, ap->name)) {
  71                         INTOFF;
  72                         ckfree(ap->val);
  73                         ap->val = savestr(val);
  74                         INTON;
  75                         return;
  76                 }
  77         }
  78         /* not found */
  79         INTOFF;
  80         ap = ckmalloc(sizeof (struct alias));
  81         ap->name = savestr(name);
  82         /*
  83          * XXX - HACK: in order that the parser will not finish reading the
  84          * alias value off the input before processing the next alias, we
  85          * dummy up an extra space at the end of the alias.  This is a crock
  86          * and should be re-thought.  The idea (if you feel inclined to help)
  87          * is to avoid alias recursions.  The mechanism used is: when
  88          * expanding an alias, the value of the alias is pushed back on the
  89          * input as a string and a pointer to the alias is stored with the
  90          * string.  The alias is marked as being in use.  When the input
  91          * routine finishes reading the string, it marks the alias not
  92          * in use.  The problem is synchronization with the parser.  Since
  93          * it reads ahead, the alias is marked not in use before the
  94          * resulting token(s) is next checked for further alias sub.  The
  95          * H A C K is that we add a little fluff after the alias value
  96          * so that the string will not be exhausted.  This is a good
  97          * idea ------- ***NOT***
  98          */
  99 #ifdef notyet
 100         ap->val = savestr(val);
 101 #else /* hack */
 102         {
 103         int len = strlen(val);
 104         ap->val = ckmalloc(len + 2);
 105         memcpy(ap->val, val, len);
 106         ap->val[len] = ' ';     /* fluff */
 107         ap->val[len+1] = '\0';
 108         }
 109 #endif
 110         ap->flag = 0;
 111         ap->next = *app;
 112         *app = ap;
 113         INTON;
 114 }
 115
 116 STATIC int
 117 unalias(const 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 INCLUDE "alias.h"
 151 SHELLPROC {
 152         rmaliases();
 153 }
 154 #endif
 155
 156 void
 157 rmaliases(void)
 158 {
 159         struct alias *ap, *tmp;
 160         int i;
 161
 162         INTOFF;
 163         for (i = 0; i < ATABSIZE; i++) {
 164                 ap = atab[i];
 165                 atab[i] = NULL;
 166                 while (ap) {
 167                         ckfree(ap->name);
 168                         ckfree(ap->val);
 169                         tmp = ap;
 170                         ap = ap->next;
 171                         ckfree(tmp);
 172                 }
 173         }
 174         INTON;
 175 }
 176
 177 struct alias *
 178 lookupalias(const char *name, int check)
 179 {
 180         struct alias *ap = *hashalias(name);
 181
 182         for (; ap; ap = ap->next) {
 183                 if (equal(name, ap->name)) {
 184                         if (check && (ap->flag & ALIASINUSE))
 185                                 return (NULL);
 186                         return (ap);
 187                 }
 188         }
 189
 190         return (NULL);
 191 }
 192
 193 /*
 194  * TODO - sort output
 195  */
 196 int
 197 aliascmd(int argc, char **argv)
 198 {
 199         char *n, *v;
 200         int ret = 0;
 201         struct alias *ap;
 202
 203         if (argc == 1) {
 204                 int i;
 205
 206                 for (i = 0; i < ATABSIZE; i++)
 207                         for (ap = atab[i]; ap; ap = ap->next) {
 208                                 if (*ap->name != '\0') {
 209                                         out1fmt("alias %s=", ap->name);
 210                                         out1qstr(ap->val);
 211                                         out1c('\n');
 212                                 }
 213                         }
 214                 return (0);
 215         }
 216         while ((n = *++argv) != NULL) {
 217                 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
 218                         if ((ap = lookupalias(n, 0)) == NULL) {
 219                                 outfmt(out2, "alias: %s not found\n", n);
 220                                 ret = 1;
 221                         } else {
 222                                 out1fmt("alias %s=", n);
 223                                 out1qstr(ap->val);
 224                                 out1c('\n');
 225                         }
 226                 else {
 227                         *v++ = '\0';
 228                         setalias(n, v);
 229                 }
 230         }
 231
 232         return (ret);
 233 }
 234
 235 int
 236 unaliascmd(int argc __unused, char **argv __unused)
 237 {
 238         int i;
 239
 240         while ((i = nextopt("a")) != '\0') {
 241                 if (i == 'a') {
 242                         rmaliases();
 243                         return (0);
 244                 }
 245         }
 246         for (i = 0; *argptr; argptr++)
 247                 i = unalias(*argptr);
 248
 249         return (i);
 250 }
 251
 252 STATIC struct alias **
 253 hashalias(const char *p)
 254 {
 255         unsigned int hashval;
 256
 257         hashval = *p << 4;
 258         while (*p)
 259                 hashval+= *p++;
 260         return &atab[hashval % ATABSIZE];
 261 }
 262
 263 /*
 264  * $PchId: alias.c,v 1.5 2006/05/22 12:41:12 philip Exp $
 265  */