alloc.c

   1 /*-
   2  * Copyright © 2009
   3  *      Thorsten Glaser <tg@mirbsd.org>
   4  *
   5  * Provided that these terms and disclaimer and all copyright notices
   6  * are retained or reproduced in an accompanying document, permission
   7  * is granted to deal in this work without restriction, including un‐
   8  * limited rights to use, publicly perform, distribute, sell, modify,
   9  * merge, give away, or sublicence.
  10  *
  11  * This work is provided “AS IS” and WITHOUT WARRANTY of any kind, to
  12  * the utmost extent permitted by applicable law, neither express nor
  13  * implied; without malicious intent or gross negligence. In no event
  14  * may a licensor, author or contributor be held liable for indirect,
  15  * direct, other damage, loss, or other issues arising in any way out
  16  * of dealing in the work, even if advised of the possibility of such
  17  * damage or existence of a defect, except proven that it results out
  18  * of said person’s immediate fault when using the work as intended.
  19  */
  20
  21 #include "sh.h"
  22
  23 #define remalloc(p,n)   realloc((p), (n))
  24
  25 #define ALLOC_ISUNALIGNED(p) (((ptrdiff_t)(p)) % ALLOC_SIZE)
  26
  27 static ALLOC_ITEM *findptr(ALLOC_ITEM **, char *, Area *);
  28
  29 void
  30 ainit(Area *ap)
  31 {
  32         /* area pointer is an ALLOC_ITEM, just the head of the list */
  33         ap->next = NULL;
  34 }
  35
  36 static ALLOC_ITEM *
  37 findptr(ALLOC_ITEM **lpp, char *ptr, Area *ap)
  38 {
  39         void *lp;
  40
  41 #ifndef MKSH_SMALL
  42         if (ALLOC_ISUNALIGNED(ptr))
  43                 goto fail;
  44 #endif
  45         /* get address of ALLOC_ITEM from user item */
  46         /*
  47          * note: the alignment of "ptr" to ALLOC_SIZE is checked
  48          * above; the "void *" gets us rid of a gcc 2.95 warning
  49          */
  50         *lpp = (lp = ptr - ALLOC_SIZE);
  51         /* search for allocation item in group list */
  52         while (ap->next != lp)
  53                 if ((ap = ap->next) == NULL) {
  54 #ifndef MKSH_SMALL
  55  fail:
  56 #endif
  57                         internal_errorf(1, "rogue pointer %p", ptr);
  58                 }
  59         return (ap);
  60 }
  61
  62 void *
  63 aresize(void *ptr, size_t numb, Area *ap)
  64 {
  65         ALLOC_ITEM *lp = NULL;
  66
  67         /* resizing (true) or newly allocating? */
  68         if (ptr != NULL) {
  69                 ALLOC_ITEM *pp;
  70
  71                 pp = findptr(&lp, ptr, ap);
  72                 pp->next = lp->next;
  73         }
  74
  75         if ((numb >= SIZE_MAX - ALLOC_SIZE) ||
  76             (lp = remalloc(lp, numb + ALLOC_SIZE)) == NULL
  77 #ifndef MKSH_SMALL
  78             || ALLOC_ISUNALIGNED(lp)
  79 #endif
  80             )
  81                 internal_errorf(1, "cannot allocate %lu data bytes",
  82                     (unsigned long)numb);
  83         /* this only works because Area is an ALLOC_ITEM */
  84         lp->next = ap->next;
  85         ap->next = lp;
  86         /* return user item address */
  87         return ((char *)lp + ALLOC_SIZE);
  88 }
  89
  90 void
  91 afree(void *ptr, Area *ap)
  92 {
  93         if (ptr != NULL) {
  94                 ALLOC_ITEM *lp, *pp;
  95
  96                 pp = findptr(&lp, ptr, ap);
  97                 /* unhook */
  98                 pp->next = lp->next;
  99                 /* now free ALLOC_ITEM */
 100                 free(lp);
 101         }
 102 }
 103
 104 void
 105 afreeall(Area *ap)
 106 {
 107         ALLOC_ITEM *lp;
 108
 109         /* traverse group (linked list) */
 110         while ((lp = ap->next) != NULL) {
 111                 /* make next ALLOC_ITEM head of list */
 112                 ap->next = lp->next;
 113                 /* free old head */
 114                 free(lp);
 115         }
 116 }