bin/sh/alias.c

   1 /*      $NetBSD: alias.c,v 1.15 2014/06/18 18:17:30 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 1.15 2014/06/18 18:17:30 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 "builtins.h"
  54 #include "var.h"
  55
  56 #define ATABSIZE 39
  57
  58 struct alias *atab[ATABSIZE];
  59
  60 STATIC void setalias(char *, char *);
  61 STATIC int unalias(char *);
  62 STATIC struct alias **hashalias(const char *);
  63
  64 STATIC
  65 void
  66 setalias(char *name, char *val)
  67 {
  68         struct alias *ap, **app;
  69
  70         app = hashalias(name);
  71         for (ap = *app; ap; ap = ap->next) {
  72                 if (equal(name, ap->name)) {
  73                         INTOFF;
  74                         ckfree(ap->val);
  75                         ap->val = savestr(val);
  76                         INTON;
  77                         return;
  78                 }
  79         }
  80         /* not found */
  81         INTOFF;
  82         ap = ckmalloc(sizeof (struct alias));
  83         ap->name = savestr(name);
  84         ap->flag = 0;
  85         /*
  86          * XXX - HACK: in order that the parser will not finish reading the
  87          * alias value off the input before processing the next alias, we
  88          * dummy up an extra space at the end of the alias.  This is a crock
  89          * and should be re-thought.  The idea (if you feel inclined to help)
  90          * is to avoid alias recursions.  The mechanism used is: when
  91          * expanding an alias, the value of the alias is pushed back on the
  92          * input as a string and a pointer to the alias is stored with the
  93          * string.  The alias is marked as being in use.  When the input
  94          * routine finishes reading the string, it markes the alias not
  95          * in use.  The problem is synchronization with the parser.  Since
  96          * it reads ahead, the alias is marked not in use before the
  97          * resulting token(s) is next checked for further alias sub.  The
  98          * H A C K is that we add a little fluff after the alias value
  99          * so that the string will not be exhausted.  This is a good
 100          * idea ------- ***NOT***
 101          */
 102 #ifdef notyet
 103         ap->val = savestr(val);
 104 #else /* hack */
 105         {
 106         int len = strlen(val);
 107         ap->val = ckmalloc(len + 2);
 108         memcpy(ap->val, val, len);
 109         ap->val[len] = ' ';     /* fluff */
 110         ap->val[len+1] = '\0';
 111         }
 112 #endif
 113         ap->next = *app;
 114         *app = ap;
 115         INTON;
 116 }
 117
 118 STATIC int
 119 unalias(char *name)
 120 {
 121         struct alias *ap, **app;
 122
 123         app = hashalias(name);
 124
 125         for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
 126                 if (equal(name, ap->name)) {
 127                         /*
 128                          * if the alias is currently in use (i.e. its
 129                          * buffer is being used by the input routine) we
 130                          * just null out the name instead of freeing it.
 131                          * We could clear it out later, but this situation
 132                          * is so rare that it hardly seems worth it.
 133                          */
 134                         if (ap->flag & ALIASINUSE)
 135                                 *ap->name = '\0';
 136                         else {
 137                                 INTOFF;
 138                                 *app = ap->next;
 139                                 ckfree(ap->name);
 140                                 ckfree(ap->val);
 141                                 ckfree(ap);
 142                                 INTON;
 143                         }
 144                         return (0);
 145                 }
 146         }
 147
 148         return (1);
 149 }
 150
 151 #ifdef mkinit
 152 MKINIT void rmaliases(void);
 153
 154 SHELLPROC {
 155         rmaliases();
 156 }
 157 #endif
 158
 159 void
 160 rmaliases(void)
 161 {
 162         struct alias *ap, *tmp;
 163         int i;
 164
 165         INTOFF;
 166         for (i = 0; i < ATABSIZE; i++) {
 167                 ap = atab[i];
 168                 atab[i] = NULL;
 169                 while (ap) {
 170                         ckfree(ap->name);
 171                         ckfree(ap->val);
 172                         tmp = ap;
 173                         ap = ap->next;
 174                         ckfree(tmp);
 175                 }
 176         }
 177         INTON;
 178 }
 179
 180 struct alias *
 181 lookupalias(const char *name, int check)
 182 {
 183         struct alias *ap = *hashalias(name);
 184
 185         for (; ap; ap = ap->next) {
 186                 if (equal(name, ap->name)) {
 187                         if (check && (ap->flag & ALIASINUSE))
 188                                 return (NULL);
 189                         return (ap);
 190                 }
 191         }
 192
 193         return (NULL);
 194 }
 195
 196 const char *
 197 alias_text(void *dummy __unused, const char *name)
 198 {
 199         struct alias *ap;
 200
 201         ap = lookupalias(name, 0);
 202         if (ap == NULL)
 203                 return NULL;
 204         return ap->val;
 205 }
 206
 207 /*
 208  * TODO - sort output
 209  */
 210 int
 211 aliascmd(int argc, char **argv)
 212 {
 213         char *n, *v;
 214         int ret = 0;
 215         struct alias *ap;
 216
 217         if (argc == 1) {
 218                 int i;
 219
 220                 for (i = 0; i < ATABSIZE; i++)
 221                         for (ap = atab[i]; ap; ap = ap->next) {
 222                                 if (*ap->name != '\0') {
 223                                         out1fmt("alias %s=", ap->name);
 224                                         print_quoted(ap->val);
 225                                         out1c('\n');
 226                                 }
 227                         }
 228                 return (0);
 229         }
 230         while ((n = *++argv) != NULL) {
 231                 if ((v = strchr(n+1, '=')) == NULL) { /* n+1: funny ksh stuff */
 232                         if ((ap = lookupalias(n, 0)) == NULL) {
 233                                 outfmt(out2, "alias: %s not found\n", n);
 234                                 ret = 1;
 235                         } else {
 236                                 out1fmt("alias %s=", n);
 237                                 print_quoted(ap->val);
 238                                 out1c('\n');
 239                         }
 240                 } else {
 241                         *v++ = '\0';
 242                         setalias(n, v);
 243                 }
 244         }
 245
 246         return (ret);
 247 }
 248
 249 int
 250 unaliascmd(int argc, char **argv)
 251 {
 252         int i;
 253
 254         while ((i = nextopt("a")) != '\0') {
 255                 if (i == 'a') {
 256                         rmaliases();
 257                         return (0);
 258                 }
 259         }
 260         for (i = 0; *argptr; argptr++)
 261                 i = unalias(*argptr);
 262
 263         return (i);
 264 }
 265
 266 STATIC struct alias **
 267 hashalias(const char *p)
 268 {
 269         unsigned int hashval;
 270
 271         hashval = *p << 4;
 272         while (*p)
 273                 hashval+= *p++;
 274         return &atab[hashval % ATABSIZE];
 275 }