Commit e879e26a authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

EAGAIN on older (correct) glibc versions indicate a problem and not the need 

for a bigger buffer and this is indeed badness for us. Making this work
on both old and new glibc versions require an ugly loop that in its worse
form cause 45 bad loops when using the correct glibc and a non-resolving
host name... :-/

We want a better fix. Badly.
parent 96d84150

lib/hostip.c

+16 −4
Original line number Diff line number Diff line
@@ -631,16 +631,28 @@ static Curl_addrinfo *my_getaddrinfo(struct SessionHandle *data, 
			  &h, /* DIFFERENCE */

			  &h_errnop);

      /* Redhat 8, using glibc 2.2.93 changed the behavior. Now all of a

         sudden this function seems to be setting EAGAIN if the given buffer

         size is too small. Previous versions are known to return ERANGE for

         the same. */

         sudden this function returns EAGAIN if the given buffer size is too

         small. Previous versions are known to return ERANGE for the same

         problem.



         This wouldn't be such a big problem if older versions wouldn't

         sometimes return EAGAIN on a common failure case. Alas, we can't

         assume that EAGAIN *or* ERANGE means ERANGE for any given version of

         glibc.



         For now, we do that and thus we may call the function repeatedly and

         fail for older glibc versions that return EAGAIN, until we run out

         of buffer size (step_size grows beyond CURL_NAMELOOKUP_SIZE).



         If anyone has a better fix, please tell us!

      */



      if((ERANGE == res) || (EAGAIN == res)) {

	step_size+=200;

	continue;

      }

      break;

    } while(1);

    } while(step_size <= CURL_NAMELOOKUP_SIZE);



    if(!h) /* failure */

      res=1;