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 #include <sys/cdefs.h>
  39 /*
  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
  53 #define ATABSIZE 39
  54
  55 STATIC struct alias *atab[ATABSIZE];
  56
  57 STATIC void setalias(const char *, const char *);
  58 STATIC int unalias(const char *);
  59 STATIC struct alias **hashalias(const char *);
  60
  61 STATIC
  62 void
  63 setalias(const char *name, const char *val)
  64 {
  65         struct alias *ap, **app;
  66
  67         app = hashalias(name);
  68         for (ap = *app; ap; ap = ap->next) {
  69                 if (equal(name, ap->name)) {
  70                         INTOFF;
  71                         ckfree(ap->val);
  72                         ap->val = savestr(val);
  73                         INTON;
  74                         return;
  75                 }
  76         }
  77         /* not found */
  78         INTOFF;
  79         ap = ckmalloc(sizeof (struct alias));
  80         ap->name = savestr(name);
  81         /*
  82          * XXX - HACK: in order that the parser will not finish reading the
  83          * alias value off the input before processing the next alias, we
  84          * dummy up an extra space at the end of the alias.  This is a crock
  85          * and should be re-thought.  The idea (if you feel inclined to help)
  86          * is to avoid alias recursions.  The mechanism used is: when
  87          * expanding an alias, the value of the alias is pushed back on the
  88          * input as a string and a pointer to the alias is stored with the
  89          * string.  The alias is marked as being in use.  When the input
  90          * routine finishes reading the string, it marks the alias not
  91          * in use.  The problem is synchronization with the parser.  Since
  92          * it reads ahead, the alias is marked not in use before the
  93          * resulting token(s) is next checked for further alias sub.  The
  94          * H A C K is that we add a little fluff after the alias value
  95          * so that the string will not be exhausted.  This is a good
  96          * idea ------- ***NOT***
  97          */
  98 #ifdef notyet
  99         ap->val = savestr(val);
 100 #else /* hack */
 101         {
 102         int len = strlen(val);
 103         ap->val = ckmalloc(len + 2);
 104         memcpy(ap->val, val, len);
 105         ap->val[len] = ' ';     /* fluff */
 106         ap->val[len+1] = '\0';
 107         }
 108 #endif
 109         ap->flag = 0;
 110         ap->next = *app;
 111         *app = ap;
 112         INTON;
 113 }
 114
 115 STATIC int
 116 unalias(const char *name)
 117 {
 118         struct alias *ap, **app;
 119
 120         app = hashalias(name);
 121
 122         for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
 123                 if (equal(name, ap->name)) {
 124                         /*
 125                          * if the alias is currently in use (i.e. its
 126                          * buffer is being used by the input routine) we
 127                          * just null out the name instead of freeing it.
 128                          * We could clear it out later, but this situation
 129                          * is so rare that it hardly seems worth it.
 130                          */
 131                         if (ap->flag & ALIASINUSE)
 132                                 *ap->name = '\0';
 133                         else {
 134                                 INTOFF;
 135                                 *app = ap->next;
 136                                 ckfree(ap->name);
 137                                 ckfree(ap->val);
 138                                 ckfree(ap);
 139                                 INTON;
 140                         }
 141                         return (0);
 142                 }
 143         }
 144
 145         return (1);
 146 }
 147
 148 #ifdef mkinit
 149 INCLUDE "alias.h"
 150 SHELLPROC {
 151         rmaliases();
 152 }
 153 #endif
 154
 155 void
 156 rmaliases(void)
 157 {
 158         struct alias *ap, *tmp;
 159         int i;
 160
 161         INTOFF;
 162         for (i = 0; i < ATABSIZE; i++) {
 163                 ap = atab[i];
 164                 atab[i] = NULL;
 165                 while (ap) {
 166                         ckfree(ap->name);
 167                         ckfree(ap->val);
 168                         tmp = ap;
 169                         ap = ap->next;
 170                         ckfree(tmp);
 171                 }
 172         }
 173         INTON;
 174 }
 175
 176 struct alias *
 177 lookupalias(const char *name, int check)
 178 {
 179         struct alias *ap = *hashalias(name);
 180
 181         for (; ap; ap = ap->next) {
 182                 if (equal(name, ap->name)) {
 183                         if (check && (ap->flag & ALIASINUSE))
 184                                 return (NULL);
 185                         return (ap);
 186                 }
 187         }
 188
 189         return (NULL);
 190 }
 191
 192 /*
 193  * TODO - sort output
 194  */
 195 int
 196 aliascmd(int argc, char **argv)
 197 {
 198         char *n, *v;
 199         int ret = 0;
 200         struct alias *ap;
 201
 202         if (argc == 1) {
 203                 int i;
 204
 205                 for (i = 0; i < ATABSIZE; i++)
 206                         for (ap = atab[i]; ap; ap = ap->next) {
 207                                 if (*ap->name != '\0') {
 208                                         out1fmt("alias %s=", ap->name);
 209                                         out1qstr(ap->val);
 210                                         out1c('\n');
 211                                 }
 212                         }
 213                 return (0);
 214         }
 215         while ((n = *++argv) != NULL) {
 216                 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
 217                         if ((ap = lookupalias(n, 0)) == NULL) {
 218                                 outfmt(out2, "alias: %s not found\n", n);
 219                                 ret = 1;
 220                         } else {
 221                                 out1fmt("alias %s=", n);
 222                                 out1qstr(ap->val);
 223                                 out1c('\n');
 224                         }
 225                 else {
 226                         *v++ = '\0';
 227                         setalias(n, v);
 228                 }
 229         }
 230
 231         return (ret);
 232 }
 233
 234 int
 235 unaliascmd(int argc __unused, char **argv __unused)
 236 {
 237         int i;
 238
 239         while ((i = nextopt("a")) != '\0') {
 240                 if (i == 'a') {
 241                         rmaliases();
 242                         return (0);
 243                 }
 244         }
 245         for (i = 0; *argptr; argptr++)
 246                 i = unalias(*argptr);
 247
 248         return (i);
 249 }
 250
 251 STATIC struct alias **
 252 hashalias(const char *p)
 253 {
 254         unsigned int hashval;
 255
 256         hashval = *p << 4;
 257         while (*p)
 258                 hashval+= *p++;
 259         return &atab[hashval % ATABSIZE];
 260 }
 261
 262 /*
 263  * $PchId: alias.c,v 1.5 2006/05/22 12:41:12 philip Exp $
 264  */