We ran into problems with a RPC client. File descriptors 32-63, 96-127, 
... are not being handled properly.

The svc_run implementation is calling svc_getreqset.
This function is broken because it is using ffs() to find bits
set in the fd_set * passed to it:

  maskp = readfds->fds_bits;
  for (sock = 0; sock < setsize; sock += NFDBITS)
    for (mask = *maskp++; (bit = ffs (mask)); mask ^= (1 << (bit - 1)))
      INTUSE(svc_getreq_common) (sock + bit - 1);

ffs() requires an int argument, but in .../sys/select.h we find

typedef long int __fd_mask;

The problem was reported in 2.3.3 version, but the problem still exists 
in glibc-2.3.5-10.3.

The problem can be fixed by using ffsl() instead.


--- glibc-2.3/sunrpc/svc.c      2004-02-09 02:47:53 -08:00
+++ glibc-2.3-fix/sunrpc/svc.c  2005-10-24 16:45:50 -07:00
@@ -372,7 +372,7 @@ svc_getreqset (fd_set *readfds)
     setsize = FD_SETSIZE;
   maskp = readfds->fds_bits;
   for (sock = 0; sock < setsize; sock += NFDBITS)
-    for (mask = *maskp++; (bit = ffs (mask)); mask ^= (1 << (bit - 1)))
+    for (mask = *maskp++; (bit = ffsl (mask)); mask ^= (1L << (bit - 1)))
       INTUSE(svc_getreq_common) (sock + bit - 1);
 }
 INTDEF (svc_getreqset)