dn_expand.c raw

   1  #include <resolv.h>
   2  
   3  int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space)
   4  {
   5  	const unsigned char *p = src;
   6  	char *dend, *dbegin = dest;
   7  	int len = -1, i, j;
   8  	if (p==end || space <= 0) return -1;
   9  	dend = dest + (space > 254 ? 254 : space);
  10  	/* detect reference loop using an iteration counter */
  11  	for (i=0; i < end-base; i+=2) {
  12  		/* loop invariants: p<end, dest<dend */
  13  		if (*p & 0xc0) {
  14  			if (p+1==end) return -1;
  15  			j = ((p[0] & 0x3f) << 8) | p[1];
  16  			if (len < 0) len = p+2-src;
  17  			if (j >= end-base) return -1;
  18  			p = base+j;
  19  		} else if (*p) {
  20  			if (dest != dbegin) *dest++ = '.';
  21  			j = *p++;
  22  			if (j >= end-p || j >= dend-dest) return -1;
  23  			while (j--) *dest++ = *p++;
  24  		} else {
  25  			*dest = 0;
  26  			if (len < 0) len = p+1-src;
  27  			return len;
  28  		}
  29  	}
  30  	return -1;
  31  }
  32  
  33  weak_alias(__dn_expand, dn_expand);
  34