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Posted to cvs@httpd.apache.org by ra...@apache.org on 2002/08/15 21:14:47 UTC
cvs commit: httpd-2.0/docs/manual/developer thread_safety.html
rasmus 2002/08/15 12:14:47
Added: docs/manual/developer thread_safety.html
Log:
Many more to come - just committing to get the framework in there so
people can start adding to it.
Revision Changes Path
1.1 httpd-2.0/docs/manual/developer/thread_safety.html
Index: thread_safety.html
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<title>Apache 2.0 Thread Safe Issues</title>
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<h1>Thread Safetyness</h1>
<p>When using any of the threaded mpms in Apache 2.0 it is important
that every function from Apache be thread safe. When linking in 3rd
party extensions it can be difficult to determine whether the resulting
server will be thread safe. Casual testing generally won't tell you this
either as thread safety problems can lead to subtle race conditons that
may only show up in certain conditions under heavy load.</p>
<h1>Common 3rd Party Libraries</h1>
<p>The following is a list of common libraries that are used by 3rd party
Apache modules. You can check to see if your module is using a potentially
unsafe library by using tools such as <tt>ldd</tt> and <tt>nm</tt>. For PHP,
for example, try this:
<pre>% ldd libphp4.so
libsablot.so.0 => /usr/local/lib/libsablot.so.0 (0x401f6000)
libexpat.so.0 => /usr/lib/libexpat.so.0 (0x402da000)
libsnmp.so.0 => /usr/lib/libsnmp.so.0 (0x402f9000)
libpdf.so.1 => /usr/local/lib/libpdf.so.1 (0x40353000)
libz.so.1 => /usr/lib/libz.so.1 (0x403e2000)
libpng.so.2 => /usr/lib/libpng.so.2 (0x403f0000)
libmysqlclient.so.11 => /usr/lib/libmysqlclient.so.11 (0x40411000)
libming.so => /usr/lib/libming.so (0x40449000)
libm.so.6 => /lib/libm.so.6 (0x40487000)
libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0x404a8000)
libjpeg.so.62 => /usr/lib/libjpeg.so.62 (0x404e7000)
libcrypt.so.1 => /lib/libcrypt.so.1 (0x40505000)
libssl.so.2 => /lib/libssl.so.2 (0x40532000)
libcrypto.so.2 => /lib/libcrypto.so.2 (0x40560000)
libresolv.so.2 => /lib/libresolv.so.2 (0x40624000)
libdl.so.2 => /lib/libdl.so.2 (0x40634000)
libnsl.so.1 => /lib/libnsl.so.1 (0x40637000)
libc.so.6 => /lib/libc.so.6 (0x4064b000)
/lib/ld-linux.so.2 => /lib/ld-linux.so.2 (0x80000000)</pre>
In addition to these libraries you will need to have a look at any libraries
linked statically into the module. You can use <tt>nm</tt> to look for individual
symbols in the module.</p>
<h2>Library List</h2>
<p>Please drop a note to rasmus@apache.org [need a better contact address here] if
you have additions or corrections to this list.</p>
<p>
<table><tr><th>Library</th><th>Version</th><th>Thread Safe?</th><th>Notes</th></tr>
<tr><td><a href="http://aspell.sourceforge.net/">ASpell/PSpell</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.sleepycat.com/">Berkeley DB</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://sources.redhat.com/bzip2/index.html">BZip2</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://cr.yp.to/cdb.html">cdb</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.washington.edu/imap/">C-Client</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.fastio.com/">cpdflib</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.ijg.org/files/">libcrypt</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td>Expat</td><td> </td><td>Yes</td><td>Need a separate parser instance per thread</td></tr>
<tr><td><a href="http://www.freetds.org/">FreeTDS</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.freetype.org/">FreeType</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.boutell.com/gd/">GD 1.8.x</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.boutell.com/gd/">GD 2.0.x</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.gnu.org/software/gdbm/gdbm.html">gdbm</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.imagemagick.org/">ImageMagick</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.enlightenment.org/pages/imlib2.html">Imlib2</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.ijg.org/files/">libjpeg</a></td><td>v6b</td><td>?</td><td> </td></tr>
<tr><td><a href="http://mysql.com">libmysqlclient</a></td><td> </td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.opaque.net/ming/">Ming</a></td><td>0.2a</td><td>?</td><td> </td></tr>
<tr><td><a href="http://net-snmp.sourceforge.net/">Net-SNMP</a></td><td>5.0.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.openldap.org/">OpenLDAP</a></td><td>2.1.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.openssl.org/">OpenSSL</a></td><td>0.96g</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.oracle.com/">liboci8 (Oracle 8+)</a></td><td>8.x,9.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://pdflib.com/">pdflib</a></td><td>4.0.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.libpng.org/pub/png/libpng.html">libpng</a></td><td>1.0.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.libpng.org/pub/png/libpng.html">libpng</a></td><td>1.2.x</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.postgresql.org/idocs/index.php?libpq-threading.html">libpq (PostgreSQL)</a></td><td>7.x</td><td>Yes</td><td>Don't share connections across threads and watch out for crypt() calls</td></tr>
<tr><td><a href="http://www.gingerall.com/charlie/ga/xml/p_sab.xml">Sablotron</a></td><td>0.95</td><td>?</td><td> </td></tr>
<tr><td><a href="http://www.gzip.org/zlib/">zlib</a></td><td>1.1.4</td><td>?</td><td> </td></tr>
</table>
</p>
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