donate.c raw

   1  #include <stdlib.h>
   2  #include <stdint.h>
   3  #include <limits.h>
   4  #include <string.h>
   5  #include <sys/mman.h>
   6  #include <errno.h>
   7  
   8  #include "meta.h"
   9  
  10  static void donate(unsigned char *base, size_t len)
  11  {
  12  	uintptr_t a = (uintptr_t)base;
  13  	uintptr_t b = a + len;
  14  	a += -a & (UNIT-1);
  15  	b -= b & (UNIT-1);
  16  	memset(base, 0, len);
  17  	for (int sc=47; sc>0 && b>a; sc-=4) {
  18  		if (b-a < (size_classes[sc]+1)*UNIT) continue;
  19  		struct meta *m = alloc_meta();
  20  		m->avail_mask = 0;
  21  		m->freed_mask = 1;
  22  		m->mem = (void *)a;
  23  		m->mem->meta = m;
  24  		m->last_idx = 0;
  25  		m->freeable = 0;
  26  		m->sizeclass = sc;
  27  		m->maplen = 0;
  28  		*((unsigned char *)m->mem+UNIT-4) = 0;
  29  		*((unsigned char *)m->mem+UNIT-3) = 255;
  30  		m->mem->storage[size_classes[sc]*UNIT-4] = 0;
  31  		queue(&ctx.active[sc], m);
  32  		a += (size_classes[sc]+1)*UNIT;
  33  	}
  34  }
  35  
  36  void __malloc_donate(char *start, char *end)
  37  {
  38  	donate((void *)start, end-start);
  39  }
  40