shell_cmds/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. 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: head/bin/sh/alias.c 317039 2017-04-16 22:10:02Z jilles $");
  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"
  49 #include "builtins.h"
  50
  51 #define ATABSIZE 39
  52
  53 static struct alias *atab[ATABSIZE];
  54 static int aliases;
  55
  56 static void setalias(const char *, const char *);
  57 static int unalias(const char *);
  58 static struct alias **hashalias(const char *);
  59
  60 static
  61 void
  62 setalias(const char *name, const char *val)
  63 {
  64         struct alias *ap, **app;
  65
  66         unalias(name);
  67         app = hashalias(name);
  68         INTOFF;
  69         ap = ckmalloc(sizeof (struct alias));
  70         ap->name = savestr(name);
  71         ap->val = savestr(val);
  72         ap->flag = 0;
  73         ap->next = *app;
  74         *app = ap;
  75         aliases++;
  76         INTON;
  77 }
  78
  79 static void
  80 freealias(struct alias *ap)
  81 {
  82         ckfree(ap->name);
  83         ckfree(ap->val);
  84         ckfree(ap);
  85 }
  86
  87 static int
  88 unalias(const char *name)
  89 {
  90         struct alias *ap, **app;
  91
  92         app = hashalias(name);
  93
  94         for (ap = *app; ap; app = &(ap->next), ap = ap->next) {
  95                 if (equal(name, ap->name)) {
  96                         /*
  97                          * if the alias is currently in use (i.e. its
  98                          * buffer is being used by the input routine) we
  99                          * just null out the name instead of freeing it.
 100                          * We could clear it out later, but this situation
 101                          * is so rare that it hardly seems worth it.
 102                          */
 103                         if (ap->flag & ALIASINUSE)
 104                                 *ap->name = '\0';
 105                         else {
 106                                 INTOFF;
 107                                 *app = ap->next;
 108                                 freealias(ap);
 109                                 INTON;
 110                         }
 111                         aliases--;
 112                         return (0);
 113                 }
 114         }
 115
 116         return (1);
 117 }
 118
 119 static void
 120 rmaliases(void)
 121 {
 122         struct alias *ap, **app;
 123         int i;
 124
 125         INTOFF;
 126         for (i = 0; i < ATABSIZE; i++) {
 127                 app = &atab[i];
 128                 while (*app) {
 129                         ap = *app;
 130                         if (ap->flag & ALIASINUSE) {
 131                                 *ap->name = '\0';
 132                                 app = &(*app)->next;
 133                         } else {
 134                                 *app = ap->next;
 135                                 freealias(ap);
 136                         }
 137                 }
 138         }
 139         aliases = 0;
 140         INTON;
 141 }
 142
 143 struct alias *
 144 lookupalias(const char *name, int check)
 145 {
 146         struct alias *ap;
 147
 148         if (aliases == 0)
 149                 return (NULL);
 150         for (ap = *hashalias(name); ap; ap = ap->next) {
 151                 if (equal(name, ap->name)) {
 152                         if (check && (ap->flag & ALIASINUSE))
 153                                 return (NULL);
 154                         return (ap);
 155                 }
 156         }
 157
 158         return (NULL);
 159 }
 160
 161 static int
 162 comparealiases(const void *p1, const void *p2)
 163 {
 164         const struct alias *const *a1 = p1;
 165         const struct alias *const *a2 = p2;
 166
 167         return strcmp((*a1)->name, (*a2)->name);
 168 }
 169
 170 static void
 171 printalias(const struct alias *a)
 172 {
 173         out1fmt("%s=", a->name);
 174         out1qstr(a->val);
 175         out1c('\n');
 176 }
 177
 178 static void
 179 printaliases(void)
 180 {
 181         int i, j;
 182         struct alias **sorted, *ap;
 183
 184         INTOFF;
 185         sorted = ckmalloc(aliases * sizeof(*sorted));
 186         j = 0;
 187         for (i = 0; i < ATABSIZE; i++)
 188                 for (ap = atab[i]; ap; ap = ap->next)
 189                         if (*ap->name != '\0')
 190                                 sorted[j++] = ap;
 191         qsort(sorted, aliases, sizeof(*sorted), comparealiases);
 192         for (i = 0; i < aliases; i++) {
 193                 printalias(sorted[i]);
 194                 if (int_pending())
 195                         break;
 196         }
 197         ckfree(sorted);
 198         INTON;
 199 }
 200
 201 int
 202 aliascmd(int argc __unused, char **argv __unused)
 203 {
 204         char *n, *v;
 205         int ret = 0;
 206         struct alias *ap;
 207
 208         nextopt("");
 209
 210         if (*argptr == NULL) {
 211                 printaliases();
 212                 return (0);
 213         }
 214         while ((n = *argptr++) != NULL) {
 215                 if ((v = strchr(n+1, '=')) == NULL) /* n+1: funny ksh stuff */
 216                         if ((ap = lookupalias(n, 0)) == NULL) {
 217                                 warning("%s: not found", n);
 218                                 ret = 1;
 219                         } else
 220                                 printalias(ap);
 221                 else {
 222                         *v++ = '\0';
 223                         setalias(n, v);
 224                 }
 225         }
 226
 227         return (ret);
 228 }
 229
 230 int
 231 unaliascmd(int argc __unused, char **argv __unused)
 232 {
 233         int i;
 234
 235         while ((i = nextopt("a")) != '\0') {
 236                 if (i == 'a') {
 237                         rmaliases();
 238                         return (0);
 239                 }
 240         }
 241         for (i = 0; *argptr; argptr++)
 242                 i |= unalias(*argptr);
 243
 244         return (i);
 245 }
 246
 247 static struct alias **
 248 hashalias(const char *p)
 249 {
 250         unsigned int hashval;
 251
 252         hashval = (unsigned char)*p << 4;
 253         while (*p)
 254                 hashval+= *p++;
 255         return &atab[hashval % ATABSIZE];
 256 }