dn_expand.c 875 B

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