bin/sh/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  * 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  * @(#)alias.c  8.3 (Berkeley) 5/4/95
  37  * $FreeBSD: src/bin/sh/alias.c,v 1.20 2005/09/02 22:43:28 stefanf Exp $
  38  * $DragonFly: src/bin/sh/alias.c,v 1.5 2007/01/04 06:35:12 pavalos Exp $
  39  */
  40
  41 #include <stdlib.h>
  42 #include "shell.h"
  43 #include "input.h"
  44 #include "output.h"
  45 #include "error.h"
  46 #include "memalloc.h"
  47 #include "mystring.h"
  48 #include "alias.h"
  49 #include "options.h"    /* XXX for argptr (should remove?) */
  50
  51 #define ATABSIZE 39
  52
  53 STATIC struct alias *atab[ATABSIZE];
  54
  55 STATIC void setalias(char *, char *);
  56 STATIC int unalias(char *);
  57 STATIC struct alias **hashalias(char *);
  58
  59 STATIC
  60 void
  61 setalias(char *name, char *val)
  62 {
  63         struct alias *ap, **app;
  64
  65         app = hashalias(name);
  66         for (ap = *app; ap; ap = ap->next) {
  67                 if (equal(name, ap->name)) {
  68                         INTOFF;
  69                         ckfree(ap->val);
  70                         ap->val = savestr(val);
  71                         INTON;
  72                         return;
  73                 }
  74         }
  75         /* not found */
  76         INTOFF;
  77         ap = ckmalloc(sizeof (struct alias));
  78         ap->name = savestr(name);
  79         /*
  80          * XXX - HACK: in order that the parser will not finish reading the
  81          * alias value off the input before processing the next alias, we
  82          * dummy up an extra space at the end of the alias.  This is a crock
  83          * and should be re-thought.  The idea (if you feel inclined to help)
  84          * is to avoid alias recursions.  The mechanism used is: when
  85          * expanding an alias, the value of the alias is pushed back on the
  86          * input as a string and a pointer to the alias is stored with the
  87          * string.  The alias is marked as being in use.  When the input
  88          * routine finishes reading the string, it marks the alias not
  89          * in use.  The problem is synchronization with the parser.  Since
  90          * it reads ahead, the alias is marked not in use before the
  91          * resulting token(s) is next checked for further alias sub.  The
  92          * H A C K is that we add a little fluff after the alias value
  93          * so that the string will not be exhausted.  This is a good
  94          * idea ------- ***NOT***
  95          */
  96 #ifdef notyet
  97         ap->val = savestr(val);
  98 #else /* hack */
  99         {
 100         int len = strlen(val);
 101         ap->val = ckmalloc(len + 2);
 102         memcpy(ap->val, val, len);
 103         ap->val[len] = ' ';     /* fluff */
 104         ap->val[len+1] = '\0';
 105         }
 106 #endif
 107         ap->flag = 0;
 108         ap->next = *app;
 109         *app = ap;
 110         INTON;
 111 }
 112
 113 STATIC int
 114 unalias(char *name)
 115 {
 116         struct alias *ap, **app;
 117
 118         app = hashalias(name);
 119
 120         for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
 121                 if (equal(name, ap->name)) {
 122                         /*
 123                          * if the alias is currently in use (i.e. its
 124                          * buffer is being used by the input routine) we
 125                          * just null out the name instead of freeing it.
 126                          * We could clear it out later, but this situation
 127                          * is so rare that it hardly seems worth it.
 128                          */
 129                         if (ap->flag & ALIASINUSE)
 130                                 *ap->name = '\0';
 131                         else {
 132                                 INTOFF;
 133                                 *app = ap->next;
 134                                 ckfree(ap->name);
 135                                 ckfree(ap->val);
 136                                 ckfree(ap);
 137                                 INTON;
 138                         }
 139                         return (0);
 140                 }
 141         }
 142
 143         return (1);
 144 }
 145
 146 #ifdef mkinit
 147 MKINIT void rmaliases(void);
 148
 149 SHELLPROC {
 150         rmaliases();
 151 }
 152 #endif
 153
 154 void
 155 rmaliases(void)
 156 {
 157         struct alias *ap, *tmp;
 158         int i;
 159
 160         INTOFF;
 161         for (i = 0; i < ATABSIZE; i++) {
 162                 ap = atab[i];
 163                 atab[i] = NULL;
 164                 while (ap) {
 165                         ckfree(ap->name);
 166                         ckfree(ap->val);
 167                         tmp = ap;
 168                         ap = ap->next;
 169                         ckfree(tmp);
 170                 }
 171         }
 172         INTON;
 173 }
 174
 175 struct alias *
 176 lookupalias(char *name, int check)
 177 {
 178         struct alias *ap = *hashalias(name);
 179
 180         for (; ap; ap = ap->next) {
 181                 if (equal(name, ap->name)) {
 182                         if (check && (ap->flag & ALIASINUSE))
 183                                 return (NULL);
 184                         return (ap);
 185                 }
 186         }
 187
 188         return (NULL);
 189 }
 190
 191 /*
 192  * TODO - sort output
 193  */
 194 int
 195 aliascmd(int argc, char **argv)
 196 {
 197         char *n, *v;
 198         int ret = 0;
 199         struct alias *ap;
 200
 201         if (argc == 1) {
 202                 int i;
 203
 204                 for (i = 0; i < ATABSIZE; i++)
 205                         for (ap = atab[i]; ap; ap = ap->next) {
 206                                 if (*ap->name != '\0') {
 207                                         out1fmt("alias %s=", ap->name);
 208                                         out1qstr(ap->val);
 209                                         out1c('\n');
 210                                 }
 211                         }
 212                 return (0);
 213         }
 214         while ((n = *++argv) != NULL) {
 215                 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
 216                         if ((ap = lookupalias(n, 0)) == NULL) {
 217                                 outfmt(out2, "alias: %s not found\n", n);
 218                                 ret = 1;
 219                         } else {
 220                                 out1fmt("alias %s=", n);
 221                                 out1qstr(ap->val);
 222                                 out1c('\n');
 223                         }
 224                 else {
 225                         *v++ = '\0';
 226                         setalias(n, v);
 227                 }
 228         }
 229
 230         return (ret);
 231 }
 232
 233 int
 234 unaliascmd(int argc __unused, char **argv __unused)
 235 {
 236         int i;
 237
 238         while ((i = nextopt("a")) != '\0') {
 239                 if (i == 'a') {
 240                         rmaliases();
 241                         return (0);
 242                 }
 243         }
 244         for (i = 0; *argptr; argptr++)
 245                 i |= unalias(*argptr);
 246
 247         return (i);
 248 }
 249
 250 STATIC struct alias **
 251 hashalias(char *p)
 252 {
 253         unsigned int hashval;
 254
 255         hashval = *p << 4;
 256         while (*p)
 257                 hashval+= *p++;
 258         return &atab[hashval % ATABSIZE];
 259 }