130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
#include <unistd.h>
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#include <stdlib.h>
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#include <time.h>
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#include <magic_def.h>
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#include <magic_mem.h>
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#include <magic_asr.h>
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#include <magic.h>
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#ifdef __MINIX
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static unsigned long magic_rand_next;
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static void magic_srand(unsigned int seed)
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{
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magic_rand_next = (unsigned long) seed;
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}
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static int magic_rand()
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{
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magic_rand_next = magic_rand_next * 1103515245 + 12345;
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return (int)(magic_rand_next % ((unsigned long)RAND_MAX + 1));
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}
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static int magic_rand_seed()
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{
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int x;
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return (int)&x + (int)&magic_rand_seed;
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}
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#else
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#define magic_srand srand
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#define magic_rand rand
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#define magic_rand_seed() time(0)
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#endif
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#define MINIMUM_PADDING 1
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PUBLIC int magic_asr_get_padding_size(int region) {
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int padding = 0;
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switch(region) {
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case MAGIC_STATE_HEAP | MAGIC_ASR_FLAG_INIT:
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if(_magic_asr_heap_max_offset){
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padding = (magic_rand() % _magic_asr_heap_max_offset) + MINIMUM_PADDING;
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}
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break;
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case MAGIC_STATE_HEAP:
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if(_magic_asr_heap_max_padding){
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padding = (magic_rand() % _magic_asr_heap_max_padding) + MINIMUM_PADDING;
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}
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break;
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case MAGIC_STATE_MAP | MAGIC_ASR_FLAG_INIT:
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if(_magic_asr_map_max_offset_pages){
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padding = ((magic_rand() % _magic_asr_map_max_offset_pages) + MINIMUM_PADDING) * magic_get_sys_pagesize();
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}
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break;
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case MAGIC_STATE_MAP:
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if(_magic_asr_map_max_padding_pages){
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padding = ((magic_rand() % _magic_asr_map_max_padding_pages) + MINIMUM_PADDING) * magic_get_sys_pagesize();
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}
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break;
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default:
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padding = -1;
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}
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return padding;
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}
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PUBLIC void magic_asr_permute_dsentries(struct _magic_dsentry **first_dsentry_ptr){
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struct _magic_dsentry *first_dsentry = *first_dsentry_ptr, *dsentry = first_dsentry, *last_dsentry;
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int n_dsentries = 0;
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int i;
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if(!_magic_asr_heap_map_do_permutate){
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/*
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* Dsentries order is reversed anyway, because newer dsentries are
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* placed at the start of the linked list, instead of the end
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*/
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return;
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}
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while(dsentry != NULL){
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last_dsentry = dsentry;
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n_dsentries++;
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dsentry = dsentry->next;
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}
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for(i=0; i < n_dsentries; i++){
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int j;
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int pos = magic_rand() % (n_dsentries - i);
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struct _magic_dsentry *prev_dsentry = NULL;
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if((i == 0) && (pos == (n_dsentries -1))){
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/*
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* Rest of for-loop won't function correctly when last dsentry is chosen first.
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* Instead, nothing has to be done in this case.
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*/
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continue;
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}
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dsentry = first_dsentry;
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for(j=0;j<pos;j++){
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prev_dsentry = dsentry;
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dsentry = dsentry->next;
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}
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if(pos == 0){
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first_dsentry = first_dsentry->next;
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}else{
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prev_dsentry->next = dsentry->next;
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}
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dsentry->next = NULL;
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last_dsentry->next = dsentry;
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last_dsentry = dsentry;
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}
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*first_dsentry_ptr = first_dsentry;
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}
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PUBLIC void magic_asr_init(){
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int seed, heap_offset;
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if(_magic_asr_seed){
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seed = _magic_asr_seed;
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}else{
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seed = magic_rand_seed();
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}
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magic_srand(seed);
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heap_offset = magic_asr_get_padding_size(MAGIC_STATE_HEAP|MAGIC_ASR_FLAG_INIT);
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if(heap_offset){
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sbrk(heap_offset);
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}
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}
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