263557 - Sending a request fails on Windows when the ber size is larger than 64MB

Status: RESOLVED FIXED

(Directory Graveyard :: LDAP C SDK, defect)

Description

[Noriko Hosoi]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.0; rv:1.7.3) Gecko/20040913 Firefox/0.10
Build Identifier: .LDAP C SDK V5.13

Sending a big entry (larger than 64MB) fails if the sender is running on the
Windows machine.  The reason is ldap request api (e.g., ldap_add_ext) eventually
calls Win32 api WriteFile (.as ber_flush -> prldap_write -> PR_Send ->
WriteFile) to send the request to the server, and WriteFile returns the error
ERROR_NO_SYSTEM_RESOURCES.

I modified
mozilla/directory/c-sd/ldap/libraries/libprldap/{ldappr-int.h,ldappr-io.c} as
attached and verified the large ber was successfully sent to the server.

If you could take a look at the change, I'd greatly appreciate it.


Reproducible: Always
Steps to Reproduce:
This is the original scenario that reveals the problem.
1. prepare an entry larger than 64MB
2. set up a master directory server and its consumer on a windows box
3. add the entry to the master server from non Windows machine

Actual Results:  
The entry is added to the master, but it's not replicated to the consumer:
the replay fails with LDAP_SERVER_DOWN on the master, although the consumer 
server is up and running.  The consumer sees the connection is closed by the 
master.


Expected Results:  
The entry is supposed to be replicated.

Comment 1

[Noriko Hosoi]

Attachment: cvs diff ldappr-int.h and ldappr-io.c

Comment 2

[Mark Smith [:mcs]]

Comment on attachment 161536 [details] [diff] [review]
cvs diff ldappr-int.h and ldappr-io.c

The patch looks OK to me.  I would not #undef PRLDAP_MAX_SEND_SIZE unless there
is a specific reason we need to do so though.

Comment 3

[Mark Smith [:mcs]]

Adding Wan-Teh to the bug CC in case there is a need to fix this inside PR_Send().

Comment 4

[Nathan Kinder]

Perhaps PRLDAP_MAX_SEND_SIZE should be a smaller value than 32MB?  Windows 
kernel will try to allocate 32MB of memory for the buffer when it prepares to 
send it.  Something smaller (8MB maybe?) may be more memory efficient.

Comment 5

[Mark Smith [:mcs]]

8MB sounds better than 32MB to me.  Noriko, has this code been tested?  Should I
check it in soon?

Comment 6

[Noriko Hosoi]

I haven't tested with 8MB.  Also, my test has been done only on Windows.  I'm
going to make it 8MB and run the test again on a couple of platforms...

Comment 7

[Noriko Hosoi]

I tested with 8MB PRLDAP_MAX_SEND_SIZE (just replacing the value in
ldappr-int.h) on Windows 2000, Solaris 8 and Linux AS2.1, and I didn't see any
problem.

Comment 8

[Wan-Teh Chang]

Let me know if you think we should fix this inside
PR_Send.

Comment 9

[Mark Smith [:mcs]]

I think it would be a good idea to fix this inside PR_Send() (we will commit the
libprldap change in any case though so this works with older copies of NSPR). 
At the least, the issue should be documented for NSPR users.

Comment 10

[Mark Smith [:mcs]]

Fix committed to the trunk (I will post the final patch in a moment):

mozilla/directory/c-sdk/ldap/libraries/libprldap/ldappr-int.h
  new revision: 5.4; previous revision: 5.3
mozilla/directory/c-sdk/ldap/libraries/libprldap/ldappr-io.c
  new revision: 5.5; previous revision: 5.4
    Fix bug # 263557 - Sending a request fails on Windows when the
                       ber size is larger than 64MB.
      Break up large messages into <= 8MB sized chunks inside prldap_write().

Comment 11

[Mark Smith [:mcs]]

Attachment: final patch

I changed the comments slightly and changed 32 to 8.

Comment 12

[Mark Smith [:mcs]]

Marked bug as Fixed.