gethostbyaddr.c raw

   1  #define _GNU_SOURCE
   2  
   3  #include <netdb.h>
   4  #include <errno.h>
   5  #include <stdlib.h>
   6  
   7  struct hostent *gethostbyaddr(const void *a, socklen_t l, int af)
   8  {
   9  	static struct hostent *h;
  10  	size_t size = 63;
  11  	struct hostent *res;
  12  	int err;
  13  	do {
  14  		free(h);
  15  		h = malloc(size+=size+1);
  16  		if (!h) {
  17  			h_errno = NO_RECOVERY;
  18  			return 0;
  19  		}
  20  		err = gethostbyaddr_r(a, l, af, h,
  21  			(void *)(h+1), size-sizeof *h, &res, &h_errno);
  22  	} while (err == ERANGE);
  23  	return err ? 0 : h;
  24  }
  25