bin/ksh/alloc.c

   1 /*      $NetBSD: alloc.c,v 1.9 2006/04/01 23:36:28 christos Exp $       */
   2
   3 /*
   4  * Copyright (c) 2002 Marc Espie.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE OPENBSD PROJECT AND CONTRIBUTORS
  16  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  18  * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OPENBSD
  19  * PROJECT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  21  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  25  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * area-based allocation built on malloc/free
  30  */
  31 #include <sys/cdefs.h>
  32 __RCSID("$NetBSD$");
  33
  34 #include "sh.h"
  35
  36 struct link {
  37         struct link *prev;
  38         struct link *next;
  39 };
  40
  41 Area *
  42 ainit(Area *ap)
  43 {
  44         ap->freelist = NULL;
  45         return ap;
  46 }
  47
  48 void
  49 afreeall(Area *ap)
  50 {
  51         struct link *l, *l2;
  52
  53         for (l = ap->freelist; l != NULL; l = l2) {
  54                 l2 = l->next;
  55                 free(l);
  56         }
  57         ap->freelist = NULL;
  58 }
  59
  60 #define L2P(l)  ( (void *)(((char *)(l)) + sizeof(struct link)) )
  61 #define P2L(p)  ( (struct link *)(((char *)(p)) - sizeof(struct link)) )
  62
  63 /* coverity[+alloc] */
  64 void *
  65 alloc(size_t size, Area *ap)
  66 {
  67         struct link *l;
  68
  69         l = malloc(sizeof(struct link) + size);
  70         if (l == NULL)
  71                 internal_errorf(1, "unable to allocate memory");
  72         l->next = ap->freelist;
  73         l->prev = NULL;
  74         if (ap->freelist)
  75                 ap->freelist->prev = l;
  76         ap->freelist = l;
  77
  78         return L2P(l);
  79 }
  80
  81 /* coverity[+alloc] */
  82 /* coverity[+free : arg-0] */
  83 void *
  84 aresize(void *ptr, size_t size, Area *ap)
  85 {
  86         struct link *l, *l2, *lprev, *lnext;
  87
  88         if (ptr == NULL)
  89                 return alloc(size, ap);
  90
  91         l = P2L(ptr);
  92         lprev = l->prev;
  93         lnext = l->next;
  94
  95         l2 = realloc(l, sizeof(struct link) + size);
  96         if (l2 == NULL)
  97                 internal_errorf(1, "unable to allocate memory");
  98         if (lprev)
  99                 lprev->next = l2;
 100         else
 101                 ap->freelist = l2;
 102         if (lnext)
 103                 lnext->prev = l2;
 104
 105         return L2P(l2);
 106 }
 107
 108 /* coverity[+free : arg-0] */
 109 void
 110 afree(void *ptr, Area *ap)
 111 {
 112         struct link *l;
 113
 114         if (!ptr)
 115                 return;
 116
 117         l = P2L(ptr);
 118
 119         if (l->prev)
 120                 l->prev->next = l->next;
 121         else
 122                 ap->freelist = l->next;
 123         if (l->next)
 124                 l->next->prev = l->prev;
 125
 126         free(l);
 127 }