1: /* Test case for gethostbyname_r bug when buffer expansion required.  */
    2: 
    3: #include <netdb.h>
    4: #include <arpa/inet.h>
    5: #include <errno.h>
    6: #include <string.h>
    7: #include <stdio.h>
    8: #include <stdlib.h>
    9: #include <unistd.h>
   10: 
   11: int
   12: main (void)
   13: {
   14:   const char *host = "www.gnu.org";
   15: 
   16:   /* This code approximates the example code in the library manual.  */
   17: 
   18:   struct hostent hostbuf, *hp;
   19:   size_t hstbuflen;
   20:   char *tmphstbuf;
   21:   int res;
   22:   int herr;
   23: 
   24:   hstbuflen = 16;               /* Make it way small to ensure ERANGE.  */
   25:   /* Allocate buffer, remember to free it to avoid memory leakage.  */
   26:   tmphstbuf = malloc (hstbuflen);
   27: 
   28:   while ((res = gethostbyname_r (host, &hostbuf, tmphstbuf, hstbuflen,
   29:                                  &hp, &herr)) == ERANGE)
   30:     {
   31:       /* Enlarge the buffer.  */
   32:       hstbuflen *= 2;
   33:       tmphstbuf = realloc (tmphstbuf, hstbuflen);
   34:     }
   35: 
   36:   if (res != 0 || hp == NULL)
   37:     {
   38:       printf ("gethostbyname_r failed: %s (errno: %m)\n", strerror (res));
   39: 
   40:       if (access ("/etc/resolv.conf", R_OK))
   41:         {
   42:           puts ("DNS probably not set up");
   43:           return 0;
   44:         }
   45: 
   46:       return 1;
   47:     }
   48: 
   49:   printf ("Got: %s %s\n", hp->h_name,
   50:           inet_ntoa (*(struct in_addr *) hp->h_addr));
   51:   return 0;
   52: }