Zabbix agent 4.0.7 and 4.2.1 breaks support for libzbxpgsql.so

[Trikke76]

https://support.zabbix.com/browse/ZBX-16028

14538:20190419:094458.679 Starting Zabbix Agent [staging]. Zabbix 4.0.7 (revision 92831).
14538:20190419:094458.679 **** Enabled features ****
14538:20190419:094458.679 IPv6 support: YES
14538:20190419:094458.679 TLS support: YES
14538:20190419:094458.679 **************************
14538:20190419:094458.679 using configuration file: /etc/zabbix/zabbix_agentd.conf
14538:20190419:094458.681 cannot load module "libzbxpgsql.so": /usr/lib64/zabbix/modules/libzbxpgsql.so: undefined symbol: __zbx_zbx_snprintf

it seems the module is broken since zabbix 4.0.7 not sure they will revert changes they made. if not it would be nice if you could create a new package

[i-ky]

You can try objcopy --redefine-sym __zbx_zbx_snprintf=zbx_snprintf libzbxpgsql.so.

[Trikke76]

Thx @i-ky
tried it but it doesn't seem to work.
Zabbix is also unwilling to fix it on there side so it would be great if a new module was made to support latest changes

https://support.zabbix.com/browse/ZBX-16028

[i-ky]

Seems I have found a dirty workaround:

1. Open libzbxpgsql.so in hex editor;
2. Find __zbx_zbx_snprintf;
3. Remove 6 bytes corresponding to __zbx_ prefix;
4. Add 6 (for every character of __zbx_) zero bytes (00) after zbx_snprintf;
5. Save your work.

After that module can be loaded without "undefined symbol" error.

#136 seems to be stuck, so we may not see a new release for a while.

[ghost]

Hi.

It's possible to have a packaged version with the workaround.

We have many postgres server, and modifyng the library on every f them would be a very long work

[OrangeDog]

@i-ky unfortunately objcopy doesn't work on dynamic symbols.

[i-ky]

@OrangeDog, it is a dynamic symbol, but not one provided by libzbxpgsql.so. Seems that objcopy does not work for undefined symbols.

[OrangeDog]

@cobra1978 you can easily make your own package with the patched binary.
Use rpmrebuild or dpkg-deb as appropriate. I recommend adding e.g. +ZBX-16028 to the version.