ram-smalloc.c 3.64 KB
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/*
 * smalloc.c
 *
 * Contains memory allocator routines
 *
 *	TEST VERSION by ceder
 */

#include <stdio.h>
#include <stdarg.h>
#include <sys/types.h>
#include <malloc.h>
#include <stdlib.h>
#include "smalloc.h"
#include "lyskomd.h"
#include "log.h"

static u_long no_of_allocated_blocks = 0;

/*
 * "safe" malloc. Handles the case when malloc returns NULL.
 * smalloc cannot fail.
 */
void *
smalloc(size_t size)
{
   unsigned int *p;

   
   p = (unsigned int *) malloc(size + 2*sizeof(unsigned int) + 2);
   if (p == NULL)
       restart_kom("Can't allocate %lu bytes.\n", (u_long)size);

   ++no_of_allocated_blocks;

   *p++ = SMALLOC_MAGIC_ALLOC;
   *p++ = size;
   ((unsigned char *) p)[size]   = 0x89;
   ((unsigned char *) p)[size+1] = 0xA7;
   
   return (void *) p;
}


void
sfree(void * ptr)	/* it is legal to sfree a NULL pointer */
{
    unsigned int *ip;

#if 0
    if ( ptr == NULL)
        log("SFREE: Freeing a NULL pointer - should be bad! /pen\n");
#endif
    
    if ( ptr != NULL )
    {
        ip = (unsigned int *) ptr;
	ip -= 2;
	switch (*ip)
	{
	    case SMALLOC_MAGIC_ALLOC:
		if (((unsigned char *) (ip+2))[ip[1]] != 0x89 ||
		    ((unsigned char *) (ip+2))[ip[1]+1] != 0xA7)
		  restart_kom("SFREE: Buffer overflow, bsize = %ul\n", ip[1]);
	        --no_of_allocated_blocks;
		*ip = SMALLOC_MAGIC_FREE;
		free( ip );
		break;

	    case SMALLOC_MAGIC_FREE:
		restart_kom("SFREE: Trying to free already freed block\n");

	    default:
		restart_kom("SFREE: Illegal magic number\n");
	}
    }
}

extern void *
srealloc(void * ptr, size_t size) /* Never fails. It is legal to */
{				    /* realloc the NULL ptr. */
    unsigned int   * ip;
    unsigned int   * new_ptr;

    if ( ptr == NULL )
	return smalloc(size);

    ip = (unsigned int *) ptr;
    ip -= 2;
    switch (*ip)
    {
        case SMALLOC_MAGIC_ALLOC:
            break;

	case SMALLOC_MAGIC_FREE:
	    restart_kom("SREALLOC: Trying to realloc freed block\n");

	default:
	    restart_kom("SREALLOC: Illegal magic number\n");
    }

    if (((unsigned char *) (ip+2))[ip[1]] != 0x89 ||
	((unsigned char *) (ip+2))[ip[1]+1] != 0xA7)
      restart_kom("SREALLOC: Buffer overflow, osize = %ul, nsize = %ul\n",
		  ip[1], size);

    *ip = SMALLOC_MAGIC_FREE;
    if ( (new_ptr = (unsigned int *) realloc((void *) ip,
				size+2*sizeof(unsigned int)+2) ) == NULL )
    {
	restart_kom("Out of memory - can't realloc. ptr = %d size = %d. ",
		    (int)ptr, size);
    }

    *new_ptr++ = SMALLOC_MAGIC_ALLOC;
    *new_ptr++ = size;

    ((unsigned char *) new_ptr)[size]   = 0x89;
    ((unsigned char *) new_ptr)[size+1] = 0xA7;
   
    return (void *) new_ptr;
}


/*
 * Allocate temporary memory, which is automatically freed after this
 * atomic call.
 */

static void **tmp_alloc_table   = NULL;
static int tmp_alloc_table_size = 0; /* Size */
static int tmp_alloc_table_use  = 0; /* Used size */

void *
tmp_alloc(u_long size)
{
    if ( tmp_alloc_table_size <= tmp_alloc_table_use )
    {
	/* Need to increas table. */
	tmp_alloc_table = srealloc (tmp_alloc_table,
				    ((++tmp_alloc_table_size)
				     * sizeof (void *)));
	log("tmp_alloc: internal table size now %d elements.\n",
	    tmp_alloc_table_size);
    }
    
    return (tmp_alloc_table[ tmp_alloc_table_use++ ]
	    = smalloc (size));
}


/*
 * Free all core which is allocated with tmp_alloc(). This is called from
 * end_of_atomic().
 */
void
free_tmp(void)
{
    int i;

    for ( i = 0; i < tmp_alloc_table_use; i++ )
    {
	sfree ( tmp_alloc_table[ i ] );
	tmp_alloc_table[ i ] = NULL;
    }

    tmp_alloc_table_use = 0;
}

void
free_all_tmp(void)
{
    free_tmp();
    sfree( tmp_alloc_table );
    tmp_alloc_table = NULL;
    tmp_alloc_table_size = 0;
}