30 lines
		
	
	
		
			568 B
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			30 lines
		
	
	
		
			568 B
		
	
	
	
		
			C
		
	
	
	
#include <_ansi.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include "sys/syscall.h"
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caddr_t
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_sbrk (int incr)
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{
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  extern char   heap_start[];		/* Defined by the linker script. */
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  static char * heap_end = NULL;
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  char *        prev_heap_end;
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  char *        sp = (char *) & sp;
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  if (heap_end == NULL)
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    heap_end = heap_start;
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  prev_heap_end = heap_end;
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  if (heap_end + incr > sp)
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    {
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#define MESSAGE "Heap and stack collision\n"
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      _write (1, MESSAGE, sizeof MESSAGE);
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      abort ();
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    }
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  heap_end += incr;
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  return (caddr_t) prev_heap_end;
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}
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