#include <resolv.h>
-#include <string.h>
-#define BITOP(a,b,op) \
- ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
-
-int dn_expand(unsigned char *b, unsigned char *pz, unsigned char *p, unsigned char *s, int outlen)
+int __dn_expand(const unsigned char *base, const unsigned char *end, const unsigned char *src, char *dest, int space)
{
- /* Remember jump destinations to detect loops and abort */
- size_t seen[512/8/sizeof(size_t)] = { 0 };
- unsigned char *sz = s + outlen;
- if (pz-b > 512) return -1;
- for (;;) {
- if (p>=pz) return -1;
- else if (*p&0xc0) {
- int j = (p[0]&1) | p[1];
- if (BITOP(seen, j, &)) return -1;
- BITOP(seen, j, |=);
- p = b + j;
+ const unsigned char *p = src;
+ char *dend, *dbegin = dest;
+ int len = -1, i, j;
+ if (p==end || space <= 0) return -1;
+ dend = dest + (space > 254 ? 254 : space);
+ /* detect reference loop using an iteration counter */
+ for (i=0; i < end-base; i+=2) {
+ /* loop invariants: p<end, dest<dend */
+ if (*p & 0xc0) {
+ if (p+1==end) return -1;
+ j = ((p[0] & 0x3f) << 8) | p[1];
+ if (len < 0) len = p+2-src;
+ if (j >= end-base) return -1;
+ p = base+j;
} else if (*p) {
- if (p+*p+1>=pz || s+*p>=sz) return -1;
- memcpy(s, p+1, *p);
- s += *p+1;
- p += *p+1;
- s[-1] = *p ? '.' : 0;
- } else return 0;
+ if (dest != dbegin) *dest++ = '.';
+ j = *p++;
+ if (j >= end-p || j >= dend-dest) return -1;
+ while (j--) *dest++ = *p++;
+ } else {
+ *dest = 0;
+ if (len < 0) len = p+1-src;
+ return len;
+ }
}
+ return -1;
}
+
+weak_alias(__dn_expand, dn_expand);