where are apache symbols?

eantoranz · 05-29-2012, 05:17 PM

Hi!

I'm trying to build phc and I find that in the configuration process, there's an error when checking for something about zend strings.... because of missing symbols (related to apache). I hacked the configure script just to see what happened and it finished successfully... however, when I try to compile phc, I get the same problem with apache symbols:

Code:

/bin/bash ./libtool --tag=CXX   --mode=link g++ -Wextra -Wno-unused-parameter -Wno-write-strings -Wno-deprecated -g -O2 -export-dynamic  -o src/phc phc.o -lgc -lgccpp -lltdl -lboost_regex-mt libphc.la -lxerces-c  -lgccpp -lgc -lphp5 -L/usr/local/php/lib -ldl -lboost_regex
chmod 755 src/phc_compile_plugin
libtool: link: g++ -Wextra -Wno-unused-parameter -Wno-write-strings -Wno-deprecated -g -O2 -o src/.libs/phc phc.o -Wl,--export-dynamic  /usr/lib/i386-linux-gnu/libltdl.so -lboost_regex-mt ./.libs/libphc.so -L/usr/lib -L/usr/local/php/lib /usr/lib/libxerces-c.so -lnsl -lpthread -lgccpp -lgc -lphp5 -ldl -lboost_regex -Wl,-rpath -Wl,/usr/local/phc/lib
/usr/local/php/lib/libphp5.so: undefined reference to `ap_get_server_version'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_sub_req_lookup_uri'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_pass_brigade'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_bucket_eos_create'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_loaded_modules'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pool_cleanup_null'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_rflush'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_add_common_vars'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_log_error'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_update_mtime'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_set_content_length'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_run_sub_req'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pool_userdata_get'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_add_version_component'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pool_userdata_set'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_palloc'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_brigade_flatten'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pstrdup'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_mpm_query'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_server_root_relative'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_hook_child_init'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_server_root'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_brigade_create'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_table_elts'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_snprintf'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_log_rerror'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_auth_type'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_add_cgi_vars'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_hook_pre_config'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_table_set'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_table_unset'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_brigade_cleanup'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_set_content_type'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pool_cleanup_register'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_hook_post_config'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_pool_cleanup_run'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_psprintf'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_hook_handler'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_table_add'
/usr/local/php/lib/libphp5.so: undefined reference to `apr_table_get'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_set_last_modified'
/usr/local/php/lib/libphp5.so: undefined reference to `unixd_config'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_get_brigade'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_destroy_sub_req'
/usr/local/php/lib/libphp5.so: undefined reference to `ap_rwrite'
collect2: ld returned 1 exit status
make[2]: *** [src/phc] Error 1
make[2]: Leaving directory `/home/antoranz/Descargas/php/phc/phc-0.3.0.1'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/antoranz/Descargas/php/phc/phc-0.3.0.1'
make: *** [all] Error 2

Where are those symbols defined? Thanks in advance.

eantoranz · 05-29-2012, 05:33 PM

Fairly interesting... the symbols are in libphp5 from the php5.2 I installed:

Code:

$ nm -gC /usr/local/php/lib/libphp5.so  | grep " apr"
         U apr_brigade_cleanup
         U apr_brigade_create
         U apr_brigade_flatten
         U apr_bucket_eos_create
         U apr_palloc
         U apr_pool_cleanup_null
         U apr_pool_cleanup_register
         U apr_pool_cleanup_run
         U apr_pool_userdata_get
         U apr_pool_userdata_set
         U apr_psprintf
         U apr_pstrdup
         U apr_snprintf
         U apr_table_add
         U apr_table_elts
         U apr_table_get
         U apr_table_set
         U apr_table_unset

Then why the hell can't the linker see it? Hell!

eantoranz · 05-29-2012, 05:37 PM

Oh.... I see it.... U is for 'undefined'... so they must be defined somwehere else, ain't that right?

eantoranz · 05-29-2012, 05:43 PM

I just checked all so files in my box and there are no symbols with those names anywhere.... what's the trick then?

eantoranz · 05-29-2012, 08:10 PM

Reading this article shed some light on what's going on: http://blog.flameeyes.eu/2010/09/you...efined-symbols

So in phc's configure I'm defining those symbols as undefinded:

Code:

LDFLAGS="-u ap_hook_child_init -u apr_table_elts -u apr_table_unset -u apr_pool_cleanup_register -u ap_rflush -u ap_pass_brigade -u apr_brigade_create -u ap_sub_req_lookup_uri -u ap_server_root -u apr_pool_cleanup_null -u ap_destroy_sub_req -u ap_mpm_query -u ap_add_cgi_vars -u ap_set_last_modified -u ap_set_content_length -u ap_hook_post_config -u ap_get_server_version -u apr_pool_userdata_get -u ap_hook_handler -u ap_rwrite -u apr_psprintf -u apr_palloc -u apr_brigade_cleanup -u unixd_config -u apr_snprintf -u ap_get_brigade -u ap_add_common_vars -u apr_table_add -u apr_bucket_eos_create -u ap_add_version_component -u ap_log_error -u ap_hook_pre_config -u apr_pool_userdata_set -u apr_pool_cleanup_run -u apr_pstrdup -u ap_set_content_type -u apr_table_get -u ap_run_sub_req -u ap_loaded_modules -u ap_server_root_relative -u apr_table_set -u ap_update_mtime -u apr_brigade_flatten -u ap_log_rerror -u ap_auth_type" ./configure --with-php=/usr/local/php --prefix=/usr/local/phc

I'm facing a problem of another kind so when I finish compiling (or it fails), I'll let you know.

eantoranz · 05-29-2012, 09:59 PM

Compilation was successful... but then it wasn't going to give itself away so easily, would it?

Code:

$ /usr/local/phc/bin/phc -c Hello.php -o hello-world
/usr/local/phc/bin/phc: symbol lookup error: /usr/local/php/lib/libphp5.so: undefined symbol: apr_pool_cleanup_null

So.... what can I try next?

eantoranz · 05-30-2012, 09:34 AM

I think I almost nailed... though without the apache symbols.

The thing is that in order to build phc, I'll have to use php _without_ apache module support. But then, in order to build my phc-compiled shared library as a php module, I'll have to use php _with_ apache.... so how about having two separate compilations of PHP? One with apache and one without?

I just tried. I compiled phc against php without apache and it works fine. Then I compiled the c code generated against php with apache. Then, I modified php.ini to include this extension, then I restarted apache, I saw this in error.log

Code:

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/php/lib/php/extensions/no-debug-zts-20060613/helloworld.so' - /usr/local/php/lib/php/extensions/no-debug-zts-20060613/helloworld.so: undefined symbol: compiler_globals in Unknown on line 0

What am I missing now?

eantoranz · 05-30-2012, 10:28 AM

Now, this is very interesting. I built and enabled the module in php full (meaning, with apache support).

When I ask php for information about this module it says the module can¿t be loaded because __MAIN__ is not defined.

Code:

$ /usr/local/php/bin/php --re helloworld
PHP Warning:  Internal error: Cannot find extension function __MAIN__ in global function table in Unknown on line 0
Extension [ <persistent> extension #24 helloworld version 1.0 ] {

  - Functions {
  }
}

There are some __MAIN__ symbols in the so:

Code:

$ nm -gC modules/helloworld.so | grep MAIN
00004180 B helloworld___MAIN___arg_info
000010b0 T zif___MAIN__

What did I miss now?

eantoranz · 05-30-2012, 11:34 AM

This is very interesting.... I built a tiny extension following this example: http://devzone.zend.com/303/extensio...-php-and-zend/

Look at the symbols in the file:

Code:

$ nm -gC modules/hello.so
         w _Jv_RegisterClasses
000020c8 A __bss_start
         w __cxa_finalize@@GLIBC_2.1.3
         w __gmon_start__
000020c8 A _edata
000020d0 A _end
         U _estrndup
00000588 T _fini
000003a4 T _init
00000530 T get_module
00002040 D hello_module_entry
000004e0 T zif_hello_world

So... there's no __MAIN__ stuff or something like that... I thought that was kind of mandatory.... and that makes me think that probably the code generated by phc has a problem... what a crash course.