title: UPDATED: Apache Chokes on PHP ldap_connect() Call
body: <p>If I run the following PHP code on the command line I get the expected result:</p>
  
  <pre><code>php -r 'var_dump(ldap_connect("ldaps://ldaps.example.com", 636));'
  resource(4) of type (ldap link)
  </code></pre>
  
  <p>However if I put this in a PHP script</p>
  
  <pre><code>&lt;?php ldap_connect("ldaps://ldaps.example.com", 636); ?&gt;
  </code></pre>
  
  <p>Apache drops the connection, for example this is what cURL returns if I hit the script from the command line:</p>
  
  <pre><code>curl http://example.com/ldap_test.php
  curl: (52) Empty reply from server
  </code></pre>
  
  <p>The Apache access_log never shows the hit to this page, and the error_log is empty.</p>
  
  <p>I know the LDAP server is working as I have tested this on two other servers. I am working on an Joyent accelerator running PHP 5.2.9 and Apache. Anyone know why Apache is choking on this?</p>
  
  <h1>Update:</h1>
  
  <p>Today I debugged Apache using GDB while running the problem script. When the script hits the ldap_connect() line I get the following in GDB:</p>
  
  <pre><code>Program received signal SIGSEGV, Segmentation fault.
  0xfe94b8bb in _free_unlocked () from /lib/libc.so.1
  </code></pre>
  
  <p>I'm not sure what is causing the segfault yet, but at least I know that Apache is actually crashing.</p>
  
  <p>Here is the full backtrace:</p>
  
  <pre><code>Breakpoint 1, 0x08094417 in ap_process_request ()
  (gdb) c
  Continuing.
  
  Program received signal SIGSEGV, Segmentation fault.
  0xfe94b8bb in _free_unlocked () from /lib/libc.so.1
  (gdb) where
  #0  0xfe94b8bb in _free_unlocked () from /lib/libc.so.1
  #1  0xfe94b86f in free () from /lib/libc.so.1
  #2  0xfde2d7e8 in ldap_x_free () from /usr/lib/libldap.so.5
  #3  0xfde3f78b in ldap_free_urldesc () from /usr/lib/libldap.so.5
  #4  0xfd0943d9 in ldap_free_urllist () from /opt/local/lib/libldap-2.4.so.2
  #5  0xfd087191 in ldap_ld_free () from /opt/local/lib/libldap-2.4.so.2
  #6  0xfd07ce8f in ldap_initialize () from /opt/local/lib/libldap-2.4.so.2
  #7  0xfd3831a1 in zif_ldap_connect () from /opt/local/lib/php/20040412/ldap.so
  #8  0xfcbda874 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #9  0xfcbe1a23 in ZEND_DO_FCALL_SPEC_CONST_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #10 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #11 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #12 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #13 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #14 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #15 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #16 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  ---Type &lt;return&gt; to continue, or q &lt;return&gt; to quit---
  #17 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #18 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #19 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #20 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #21 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #22 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #23 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #24 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #25 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #26 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #27 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #28 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #29 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #30 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
  ---Type &lt;return&gt; to continue, or q &lt;return&gt; to quit---
     from /opt/local/lib/httpd/mod_php5.so
  #31 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #32 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #33 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #34 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #35 0xfcbda985 in zend_do_fcall_common_helper_SPEC ()
     from /opt/local/lib/httpd/mod_php5.so
  #36 0xfcbdad65 in ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER ()
     from /opt/local/lib/httpd/mod_php5.so
  #37 0xfcbd9e99 in execute () from /opt/local/lib/httpd/mod_php5.so
  #38 0xfcbbebaa in zend_execute_scripts () from /opt/local/lib/httpd/mod_php5.so
  #39 0xfcb7f40e in php_execute_script () from /opt/local/lib/httpd/mod_php5.so
  #40 0xfcc509ca in php_handler () from /opt/local/lib/httpd/mod_php5.so
  #41 0x08085c2a in ap_run_handler ()
  #42 0x0808638e in ap_invoke_handler ()
  #43 0x08094ca7 in ap_internal_redirect ()
  #44 0xfe48c232 in handler_redirect () from /opt/local/lib/httpd/mod_rewrite.so
  #45 0x08085c2a in ap_run_handler ()
  #46 0x0808638e in ap_invoke_handler ()
  #47 0x08094471 in ap_process_request ()
  #48 0x0809177c in ap_process_http_connection ()
  ---Type &lt;return&gt; to continue, or q &lt;return&gt; to quit---
  #49 0x0808d426 in ap_run_process_connection ()
  #50 0x0808d858 in ap_process_connection ()
  #51 0x08099e89 in child_main ()
  #52 0x08099f65 in make_child ()
  #53 0x0809a472 in ap_mpm_run ()
  #54 0x080709ab in main ()
  (gdb) 
  </code></pre>
  
  <h1>Update 2:</h1>
  
  <p>From what I can tell the problem begins in these two function calls:</p>
  
  <pre><code>#3  0xfde3f78b in ldap_free_urldesc () from /usr/lib/libldap.so.5
  #4  0xfd0943d9 in ldap_free_urllist () from /opt/local/lib/libldap-2.4.so.2
  </code></pre>
  
  <p>The function in #4 (ldap_free_urllist) is called from a library in /opt/local/lib/libldap-2.4.so.2 and #3 is called from a library in /usr/lib/libldap.so.5. I don't know enough to tell whether or not it is normal, but I would assume it is not. So somehow both of these LDAP libraries are getting loaded.</p>