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      1 /*-
      2  * Copyright  2009
      3  *	Thorsten Glaser <tg (at) 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 persons immediate fault when using the work as intended.
     19  */
     20 
     21 #include "sh.h"
     22 
     23 __RCSID("$MirOS: src/bin/mksh/lalloc.c,v 1.11 2009/08/08 13:08:51 tg Exp $");
     24 
     25 /* build with CPPFLAGS+= -DUSE_REALLOC_MALLOC=0 on ancient systems */
     26 #if defined(USE_REALLOC_MALLOC) && (USE_REALLOC_MALLOC == 0)
     27 #define remalloc(p,n)	((p) == NULL ? malloc(n) : realloc((p), (n)))
     28 #else
     29 #define remalloc(p,n)	realloc((p), (n))
     30 #endif
     31 
     32 #define ALLOC_ISUNALIGNED(p) (((ptrdiff_t)(p)) % ALLOC_SIZE)
     33 
     34 static ALLOC_ITEM *findptr(ALLOC_ITEM **, char *, Area *);
     35 
     36 void
     37 ainit(Area *ap)
     38 {
     39 	/* area pointer is an ALLOC_ITEM, just the head of the list */
     40 	ap->next = NULL;
     41 }
     42 
     43 static ALLOC_ITEM *
     44 findptr(ALLOC_ITEM **lpp, char *ptr, Area *ap)
     45 {
     46 	void *lp;
     47 
     48 #ifndef MKSH_SMALL
     49 	if (ALLOC_ISUNALIGNED(ptr))
     50 		goto fail;
     51 #endif
     52 	/* get address of ALLOC_ITEM from user item */
     53 	/*
     54 	 * note: the alignment of "ptr" to ALLOC_SIZE is checked
     55 	 * above; the "void *" gets us rid of a gcc 2.95 warning
     56 	 */
     57 	*lpp = (lp = ptr - ALLOC_SIZE);
     58 	/* search for allocation item in group list */
     59 	while (ap->next != lp)
     60 		if ((ap = ap->next) == NULL) {
     61 #ifndef MKSH_SMALL
     62  fail:
     63 #endif
     64 			internal_errorf("rogue pointer %p", ptr);
     65 		}
     66 	return (ap);
     67 }
     68 
     69 void *
     70 aresize(void *ptr, size_t numb, Area *ap)
     71 {
     72 	ALLOC_ITEM *lp = NULL;
     73 
     74 	/* resizing (true) or newly allocating? */
     75 	if (ptr != NULL) {
     76 		ALLOC_ITEM *pp;
     77 
     78 		pp = findptr(&lp, ptr, ap);
     79 		pp->next = lp->next;
     80 	}
     81 
     82 	if ((numb >= SIZE_MAX - ALLOC_SIZE) ||
     83 	    (lp = remalloc(lp, numb + ALLOC_SIZE)) == NULL
     84 #ifndef MKSH_SMALL
     85 	    || ALLOC_ISUNALIGNED(lp)
     86 #endif
     87 	    )
     88 		internal_errorf("cannot allocate %lu data bytes",
     89 		    (unsigned long)numb);
     90 	/* this only works because Area is an ALLOC_ITEM */
     91 	lp->next = ap->next;
     92 	ap->next = lp;
     93 	/* return user item address */
     94 	return ((char *)lp + ALLOC_SIZE);
     95 }
     96 
     97 void
     98 afree(void *ptr, Area *ap)
     99 {
    100 	if (ptr != NULL) {
    101 		ALLOC_ITEM *lp, *pp;
    102 
    103 		pp = findptr(&lp, ptr, ap);
    104 		/* unhook */
    105 		pp->next = lp->next;
    106 		/* now free ALLOC_ITEM */
    107 		free(lp);
    108 	}
    109 }
    110 
    111 void
    112 afreeall(Area *ap)
    113 {
    114 	ALLOC_ITEM *lp;
    115 
    116 	/* traverse group (linked list) */
    117 	while ((lp = ap->next) != NULL) {
    118 		/* make next ALLOC_ITEM head of list */
    119 		ap->next = lp->next;
    120 		/* free old head */
    121 		free(lp);
    122 	}
    123 }
    124