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