Missing symbols in php8.0-xml? Causes problem with PECL xmlrpc

[mdrmdrmdr]

I'm not sure if this is a bug. I recently upgraded my home automation Raspberry to PHP 8.0.3. For that I also changed the repository to https://packages.sury.org/php. On the Raspberry I use the home automation software Homegear. Using the PHP interface of Homegear, I get errors which have not been there with PHP 7.4.

I tracked it down to xmlrpc, which went to PECL. I am in contact with the maintainer to find a solution to the problem.

The error message when using the Homegear PHP interface is:

php: symbol lookup error: /usr/lib/php/20200930/xmlrpc.so: undefined symbol: XML_ParserCreate

Since /usr/lib/php/20200930/xmlrpc.so does use but not define XML_ParserCreate (nm output below), we expected this to be defined in /usr/lib/php/20200930/xml.so. Actually there are no symbols defined at all there:

$ nm /usr/lib/php/20200930/xmlrpc.so |grep XML_ParserCreate
         U XML_ParserCreate

$ nm /usr/lib/php/20200930/xml.so
nm: /usr/lib/php/20200930/xml.so: no symbols

Is that a bug causing my problem? Or do I just think in the wrong direction?

I am running on:

Linux raspberry 5.10.17-v7+ #1403 SMP Mon Feb 22 11:29:51 GMT 2021 armv7l GNU/Linux
Architecture: armhf
Linux: Description: Raspbian GNU/Linux 10 (buster)

With PHP packages installed:

$ dpkg --get-selections | grep php8
libapache2-mod-php8.0                           install
php8.0                                          install
php8.0-cli                                      install
php8.0-common                                   install
php8.0-curl                                     install
php8.0-dev                                      install
php8.0-fpm                                      install
php8.0-mbstring                                 install
php8.0-opcache                                  install
php8.0-readline                                 install
php8.0-soap                                     install
php8.0-sqlite3                                  install
php8.0-xml                                      install

Thanks for any help.

[oerdnj]

What is your libxml2 version and output of ldd on the extension?

[mdrmdrmdr]

Asking this?

$ ldd /usr/lib/arm-linux-gnueabihf/libxml2.so
        linux-vdso.so.1 (0x7eee1000)
        /usr/lib/arm-linux-gnueabihf/libarmmem-${PLATFORM}.so => /usr/lib/arm-linux-gnueabihf/libarmmem-v7l.so (0x76e67000)
        libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0x76e45000)
        libicui18n.so.65 => /usr/lib/arm-linux-gnueabihf/libicui18n.so.65 (0x76c54000)
        libicuuc.so.65 => /usr/lib/arm-linux-gnueabihf/libicuuc.so.65 (0x76b0a000)
        libicudata.so.65 => /usr/lib/arm-linux-gnueabihf/libicudata.so.65 (0x7504a000)
        libz.so.1 => /lib/arm-linux-gnueabihf/libz.so.1 (0x7501f000)
        liblzma.so.5 => /lib/arm-linux-gnueabihf/liblzma.so.5 (0x74fee000)
        libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0x74f6c000)
        libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x74e1e000)
        /lib/ld-linux-armhf.so.3 (0x76f8c000)
        libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0x74cd7000)
        libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0x74caa000)
        libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0x74c80000)

[oerdnj]

Nah, ldd /usr/lib/php/20200930/xmlrpc.so

And package versions of the linked libraries. XML_ParserCreate is function from libexpat library.

[mdrmdrmdr]

What do you mean by package versions of the linked libraries? How do I get this?

$ ldd /usr/lib/php/20200930/xmlrpc.so
        linux-vdso.so.1 (0x7efe9000)
        /usr/lib/arm-linux-gnueabihf/libarmmem-${PLATFORM}.so => /usr/lib/arm-linux-gnueabihf/libarmmem-v7l.so (0x76ee6000)
        libxml2.so.2 => /usr/lib/arm-linux-gnueabihf/libxml2.so.2 (0x76dc7000)
        libc.so.6 => /lib/arm-linux-gnueabihf/libc.so.6 (0x76c79000)
        libdl.so.2 => /lib/arm-linux-gnueabihf/libdl.so.2 (0x76c66000)
        libicui18n.so.65 => /usr/lib/arm-linux-gnueabihf/libicui18n.so.65 (0x76a75000)
        libicuuc.so.65 => /usr/lib/arm-linux-gnueabihf/libicuuc.so.65 (0x7692b000)
        libicudata.so.65 => /usr/lib/arm-linux-gnueabihf/libicudata.so.65 (0x74e6b000)
        libz.so.1 => /lib/arm-linux-gnueabihf/libz.so.1 (0x74e40000)
        liblzma.so.5 => /lib/arm-linux-gnueabihf/liblzma.so.5 (0x74e0f000)
        libm.so.6 => /lib/arm-linux-gnueabihf/libm.so.6 (0x74d8d000)
        /lib/ld-linux-armhf.so.3 (0x76f1d000)
        libstdc++.so.6 => /usr/lib/arm-linux-gnueabihf/libstdc++.so.6 (0x74c46000)
        libgcc_s.so.1 => /lib/arm-linux-gnueabihf/libgcc_s.so.1 (0x74c19000)
        libpthread.so.0 => /lib/arm-linux-gnueabihf/libpthread.so.0 (0x74bef000)

[oerdnj]

Hmm, just a thought (I can't check from mobile) - is there a "priority" line in the /etc/PHP/8.0/mods-available/xmlrpc.ini file? Check other files on how it should look like and then perhaps bump it to the same value as it had in PHP 7.4?

[oerdnj]

After changing the priority you'll need to run phpdismod xmlrpc and phpenmod xmlrpc

[mdrmdrmdr]

There is no xmlrpc.ini in /etc/php/8.0/mods-available.
I did not install it via apt install php8.0-xmlrpc but with pecl install channel://pecl.php.net/xmlrpc-1.0.0RC2.

I still have php 7.4 installed as a fallback if php 8 does not work for my software. Should I uninstall it?

[oerdnj]

Oh, then why are you reporting it here?

Nevertheless, most probably you are loading the xmlrpc extension before loading its dependencies first.

BTW there's a package for php8.0-xmlrpc

[mdrmdrmdr]

I don't understand your close. Why?

I just deinstalled php7.4. No change. Same error.
I just deinstalled the PECL version of xmlrpc (thought it's the recomended way) and installed php8.0-xmlrpc.

Now a new error in the php logfile and my software does now work at all. Went back to the PECL version for now.

[17-Mar-2021 23:08:02 Europe/Berlin] PHP Warning:  PHP Startup: Unable to load dynamic library 'xmlrpc.so' (tried: /usr/lib/php/20200930/xmlrpc.so (/usr/lib/php/20200930/xmlrpc.so: undefined symbol: XML_GetErrorCode), /usr/lib/php/20200930/xmlrpc.so.so (/usr/lib/php/20200930/xmlrpc.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
[17-Mar-2021 23:08:02 Europe/Berlin] PHP Warning:  PHP Startup: Unable to load dynamic library 'xmlrpc.so' (tried: /usr/lib/php/20200930/xmlrpc.so (/usr/lib/php/20200930/xmlrpc.so: undefined symbol: XML_GetErrorCode), /usr/lib/php/20200930/xmlrpc.so.so (/usr/lib/php/20200930/xmlrpc.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
[17-Mar-2021 23:08:02 Europe/Berlin] PHP Fatal error:  Uncaught Error: Call to undefined function XMLRPC\xmlrpc_encode_request() in /var/lib/homegear/scripts/HM-XMLRPC-Client/Client.php:227
Stack trace:
#0 /var/lib/homegear/scripts/HM-XMLRPC-Client/Client.php(235): XMLRPC\Client->send()
#1 /opt/automation/test_temp.php(36): XMLRPC\Client->__call()
#2 {main}
  thrown in /var/lib/homegear/scripts/HM-XMLRPC-Client/Client.php on line 227
[17-Mar-2021 23:09:02 Europe/Berlin] PHP Warning:  PHP Startup: Unable to load dynamic library 'xmlrpc.so' (tried: /usr/lib/php/20200930/xmlrpc.so (/usr/lib/php/20200930/xmlrpc.so: undefined symbol: XML_GetErrorCode), /usr/lib/php/20200930/xmlrpc.so.so (/usr/lib/php/20200930/xmlrpc.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0

[oerdnj]

I don't understand your close. Why?

This is a tracker to track issues with the packages and there's no issue with the packages since you installed the extension from PECL. I can't help you unless you can reproduce the issue on clean installation and not on system where you did X random things.

[mdrmdrmdr]

It was a clean installation. I just upgraded php 7.4 to 8.0 (including php8.0-xmlrpc) and the problems started around xmlrpc.
Everwhere is written that Since 8.0, the XML-RPC extension has been moved to PECL and it is no longer included in PHP core.
So I took it from there.

Nevermind, thanks anyway...

[oerdnj]

Both issues are caused by upstream and needs to be fixed there - there's missing expat dependency and maybe even libxmlrpc-epi, so it breaks unless something else pulls libexpat.so.1 into the PHP process.

See the difference?

root@calcifer:~# ldd /usr/lib/php/20190902/xmlrpc.so 
        linux-vdso.so.1 (0x00007ffeac5a5000)
        libxmlrpc-epi.so.0 => /usr/lib/x86_64-linux-gnu/libxmlrpc-epi.so.0 (0x00007fcb8f712000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fcb8f54d000)
        libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007fcb8f51e000)
        /lib64/ld-linux-x86-64.so.2 (0x00007fcb8f74f000)
root@calcifer:~# ldd /usr/lib/php/20200930/xmlrpc.so 
        linux-vdso.so.1 (0x00007ffed53fc000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f7078094000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f7078292000)

But it has nothing to do with the packaging itself. The PECL xmlrpc extension is broken.

[mdrmdrmdr]

Ok, thanks again. I'll talk to the maintainer of the PECL xmlrpc.

[cmb69]

there's missing expat dependency

ext/xmlrpc does not depend on libexpat; it should be able to use the compat layer over libxml2 provided by ext/xml instead. However, apparently I forgot that system libxmlrpc-epi may be built against libexpat. I guess the solution is that ext/xmlrpc needs to check whether ext/xml provides the respective symbols, if --with-expat is not configured, and to bail out otherwise.

Anyhow, thank you @oerdnj, that was helpful for me. :)

maybe even libxmlrpc-epi,

ext/xmlrpc has a bundled libxmlrpc-epi, which uses the ZendMM, and as such heeds memory_limit what seems like a good idea. OTOH, that bundled lib is not quite up to date. Anyway, which lib to chose is configurable, so that's a documentation issue (if at all).

[oerdnj]

@cmb69 Umm, maybe this is needed at least on Debian? I am not sure about the other platforms though, it might be just Debian quirk.

diff --git a/xmlrpc-1.0.0RC2/config.m4 b/xmlrpc-1.0.0RC2/config.m4
index 9de44ef..4ac9f10 100644
--- a/xmlrpc-1.0.0RC2/config.m4
+++ b/xmlrpc-1.0.0RC2/config.m4
@@ -97,7 +97,7 @@ elif test "$PHP_XMLRPC" != "no"; then
   fi

   PHP_ADD_INCLUDE($XMLRPC_DIR)
-  PHP_ADD_LIBRARY_WITH_PATH(xmlrpc, $XMLRPC_DIR/$PHP_LIBDIR, XMLRPC_SHARED_LIBADD)
+  PHP_ADD_LIBRARY_WITH_PATH(xmlrpc-epi, $XMLRPC_DIR/$PHP_LIBDIR, XMLRPC_SHARED_LIBADD)
   PHP_NEW_EXTENSION(xmlrpc,xmlrpc-epi-php.c, $ext_shared)
   XMLRPC_MODULE_TYPE=external
 fi

[cmb69]

Thanks, I think you're correct. @remicollet, can you confirm that libxmlrpc-epi i should be used on RHEL/Fedora as well?

[mdrmdrmdr]

A final comment from my side: A manual build of PECL xmlrpc with CPPFLAGS=-I/usr/include/libxml2/ and --with-expat solves my issue with the Homegear PHP interface under PHP 8. Thanks all for the help and sorry @oerdnj if i missused your issue tracker.