Re: Bugfix: wait4msg() hangs when using SSL/TLS (ITS#446)

[Kurt@OpenLDAP.org]

I've experimented with this patch a bit (without TLS) and found
that it causes test009-referral to hang.  ldapsearch has data
pending from the master but is blocked reading from the slave.

(gdb) where
#0  0x18183f44 in read () from /usr/lib/libc.so.3
#1  0x805a3d5 in stream_read (sb=0x806a000, buf=0x806718c, len=1)
    at ../../../libraries/liblber/sockbuf.c:911
#2  0x8059df3 in ber_pvt_sb_read (sb=0x806a000, buf_arg=0x806718c, len=1)
    at ../../../libraries/liblber/sockbuf.c:504
#3  0x8058b6b in ber_get_next (sb=0x806a000, len=0xbfbfcb70, ber=0x8067180)
    at ../../../libraries/liblber/io.c:525
#4  0x804ca47 in try_read1msg (ld=0x806a000, msgid=-1, all=1, sb=0x806a000, 
    lc=0x8061100, result=0xbfbfcc34)
    at ../../../libraries/libldap/result.c:296
#5  0x804c890 in wait4msg (ld=0x806a000, msgid=-1, all=1, timeout=0x0, 
    result=0xbfbfcc34) at ../../../libraries/libldap/result.c:208
#6  0x804c714 in ldap_result (ld=0x806a000, msgid=-1, all=1, timeout=0x0, 
    result=0xbfbfcc34) at ../../../libraries/libldap/result.c:137
#7  0x804aef7 in dosearch (ld=0x806a000, 
    base=0x8061040 "o=University of Michigan, c=US", scope=2, attrs=0x0, 
    attrsonly=0, filtpatt=0x0, value=0x8062050 "sn=jensen")
    at ../../../clients/tools/ldapsearch.c:540
#8  0x804acfb in main (argc=11, argv=0xbfbfd4e8)
    at ../../../clients/tools/ldapsearch.c:471
#9  0x804a095 in _start ()

At 05:42 AM 2/8/00 GMT, andrew.hacking@cai.com wrote:
>Full_Name: Andrew Hacking
>Version: -devel
>OS: Linux
>URL: ftp://ftp.openldap.org/incoming/andrew-hacking-000208-2.patch
>Submission from: (NULL) (24.192.12.154)
>
>
>Sorry for the re-post, my email address was changed today...
>
>libldap wait4msg() hangs under various conditions when using SSL/TLS.
>
>The specifics are that wait4msg blocks in do_ldap_select()
>while waiting for data that has _already_ been buffered by the
>OpenSSL library. do_ldap_select() should never be called until
>the SSL/TLS buffers have been exhausted.
>
>The patch changes to wait4msg() changes the way messages are read to ensure the
>SSL/TLS buffers really are exhausted before calling do_ldap_select()
>
>try_read1msg() is also changed to return 'exhausted' (-3) on an
>EWOULDBLOCK/EAGAIN condition.  This differentiates EWOULDBLOCK/EAGAIN
>(ie the underlying sockbuf is now exhausted) with the 'keep looking' (-2)
>condition.
>
>
>
>
>