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implement realloc(), just like the user-land version, except it takes 

"type" and "flags" arguments a la kernel malloc().
This commit is contained in:
cgd 1996-08-27 20:01:42 +00:00
parent 2c47809239
commit f8ed933394
2 changed files with 88 additions and 2 deletions
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86
sys/kern/kern_malloc.c
View File

@ -1,6 +1,7 @@
/* $NetBSD: kern_malloc.c,v 1.19 1996/08/13 23:25:10 thorpej Exp $ */
/* $NetBSD: kern_malloc.c,v 1.20 1996/08/27 20:01:42 cgd Exp $ */
/*
* Copyright 1996 Christopher G. Demetriou. All rights reserved.
* Copyright (c) 1987, 1991, 1993
* The Regents of the University of California. All rights reserved.
*
@ -369,6 +370,89 @@ free(addr, type)
splx(s);
}
/*
* Change the size of a block of memory.
*/
void *
realloc(curaddr, newsize, type, flags)
void *curaddr;
unsigned long newsize;
int type, flags;
{
register struct kmemusage *kup;
long cursize;
void *newaddr;
#ifdef DIAGNOSTIC
long alloc;
#endif
/*
* Realloc() with a NULL pointer is the same as malloc().
*/
if (curaddr == NULL)
return (malloc(newsize, type, flags));
/*
* Realloc() with zero size is the same as free().
*/
if (newsize == 0) {
free(curaddr, type);
return (NULL);
}
/*
* Find out how large the old allocation was (and do some
* sanity checking).
*/
kup = btokup(curaddr);
cursize = 1 << kup->ku_indx;
#ifdef DIAGNOSTIC
/*
* Check for returns of data that do not point to the
* beginning of the allocation.
*/
if (cursize > NBPG * CLSIZE)
alloc = addrmask[BUCKETINDX(NBPG * CLSIZE)];
else
alloc = addrmask[kup->ku_indx];
if (((u_long)curaddr & alloc) != 0)
panic("realloc: unaligned addr %p, size %ld, type %s, mask %ld\n",
curaddr, cursize, memname[type], alloc);
#endif /* DIAGNOSTIC */
if (cursize > MAXALLOCSAVE)
cursize = ctob(kup->ku_pagecnt);
/*
* If we already actually have as much as they want, we're done.
*/
if (newsize <= cursize)
return (curaddr);
/*
* Can't satisfy the allocation with the existing block.
* Allocate a new one and copy the data.
*/
newaddr = malloc(newsize, type, flags);
if (newaddr == NULL) {
/*
* Malloc() failed, because flags included M_NOWAIT.
* Return NULL to indicate that failure. The old
* pointer is still valid.
*/
return NULL;
}
bcopy(curaddr, newaddr, cursize);
/*
* We were successful: free the old allocation and return
* the new one.
*/
free(curaddr, type);
return (newaddr);
}
/*
* Initialize the kernel memory allocator
*/

4
sys/sys/malloc.h
View File

@ -1,4 +1,4 @@
/* $NetBSD: malloc.h,v 1.23 1996/04/05 04:52:52 mhitch Exp $ */
/* $NetBSD: malloc.h,v 1.24 1996/08/27 20:01:51 cgd Exp $ */
/*
* Copyright (c) 1987, 1993
@ -330,5 +330,7 @@ extern char *kmembase;
extern struct kmembuckets bucket[];
extern void *malloc __P((unsigned long size, int type, int flags));
extern void free __P((void *addr, int type));
extern void *realloc __P((void *curaddr, unsigned long newsize, int type,
int flags));
#endif /* _KERNEL */
#endif /* !_SYS_MALLOC_H_ */