<html>
<body>
<div style="font-family: Verdana, Arial, Helvetica, Sans-Serif;">
<table bgcolor="#f9f3c9" width="100%" cellpadding="8" style="border: 1px #c9c399 solid;">
<tr>
<td>
This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1622/">https://reviewboard.asterisk.org/r/1622/</a>
</td>
</tr>
</table>
<br />
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<p style="margin-top: 0;">On December 14th, 2011, 11:08 a.m., <b>Tilghman Lesher</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<table width="100%" border="0" bgcolor="white" style="border: 1px solid #C0C0C0; border-collapse: collapse; margin: 2px padding: 2px;">
<thead>
<tr>
<th colspan="4" bgcolor="#F0F0F0" style="border-bottom: 1px solid #C0C0C0; font-size: 9pt; padding: 4px 8px; text-align: left;">
<a href="https://reviewboard.asterisk.org/r/1622/diff/1/?file=22212#file22212line731" style="color: black; font-weight: bold; text-decoration: underline;">/branches/1.8/res/res_odbc.c</a>
<span style="font-weight: normal;">
(Diff revision 1)
</span>
</th>
</tr>
</thead>
<tbody style="background-color: #e4d9cb; padding: 4px 8px; text-align: center;">
<tr>
<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">SQLRETURN ast_odbc_ast_str_SQLGetData(struct ast_str **buf, int pmaxlen, SQLHSTMT StatementHandle, SQLUSMALLINT ColumnNumber, SQLSMALLINT TargetType, SQLLEN *StrLen_or_Ind)</pre></td>
</tr>
</tbody>
<tbody>
<tr>
<th bgcolor="#b1ebb0" style="border-right: 1px solid #C0C0C0;" align="right"><font size="2"></font></th>
<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "></pre></td>
<th bgcolor="#b1ebb0" style="border-left: 1px solid #C0C0C0; border-right: 1px solid #C0C0C0;" align="right"><font size="2">731</font></th>
<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cm">/* We expect a read lock on obj->lock here */</span></pre></td>
</tr>
</tbody>
</table>
<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Actually, you expect "at least" a read lock. There are cases below where you've obtained a write lock before calling the sanity checking function.
Maybe create an internal version of this where the type of lock held is passed, and you escalate the lock only if it's necessary (and avoid a WARNING).</pre>
</blockquote>
<p>On December 14th, 2011, 11:10 a.m., <b>Tilghman Lesher</b> wrote:</p>
<blockquote style="margin-left: 1em; border-left: 2px solid #d0d0d0; padding-left: 10px;">
<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Also, because this is a public API, assuming that a lock is held isn't correct unless you document it in the header file. That speaks doubly for a private version of this.</pre>
</blockquote>
</blockquote>
<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">That warning message really has nothing to do with turning over the read lock to get the write lock. I've created an alternate version of the function called ast_sanity_check_wrlocked which forgoes the lock switching step.
I'm taking over the patch for Walter since he can't finish it right now. It will be moving to a new review in a little while so that I can post the new diffs.</pre>
<br />
<p>- jrose</p>
<br />
<p>On December 14th, 2011, 3:01 a.m., wdoekes wrote:</p>
<table bgcolor="#fefadf" width="100%" cellspacing="0" cellpadding="8" style="background-image: url('https://reviewboard.asterisk.org/media/rb/images/review_request_box_top_bg.png'); background-position: left top; background-repeat: repeat-x; border: 1px black solid;">
<tr>
<td>
<div>Review request for Asterisk Developers and Tilghman Lesher.</div>
<div>By wdoekes.</div>
<p style="color: grey;"><i>Updated Dec. 14, 2011, 3:01 a.m.</i></p>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: 1px solid #b8b5a0">
<tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">See bug report: under certain circumstances res_odbc can be made to crash.
Adding a shared lock around usage of the con odbc handle is a way to fix this. When a reconnect is attempted, an exclusive lock is held. Result: no usage attempts while reconnecting.
This is hacked up quickly, so could use a bit of review; it wouldn't surprise me if I double-lock something somewhere. (And the assertion I added fails too.) Also, this could be the wrong way to approach this altogether.
@tilghman: is there a reason why ->up is set to 0 after query failure? (See same question in bug report at Cause (1).)</pre>
</td>
</tr>
</table>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
<table width="100%" bgcolor="#ffffff" cellspacing="0" cellpadding="10" style="border: 1px solid #b8b5a0">
<tr>
<td>
<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">With the patch, I'm not getting the easy crashes anymore.</pre>
</td>
</tr>
</table>
<div style="margin-top: 1.5em;">
<b style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Bugs: </b>
<a href="https://issues.asterisk.org/jira/browse/ASTERISK-19011">ASTERISK-19011</a>
</div>
<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
<ul style="margin-left: 3em; padding-left: 0;">
<li>/branches/1.8/include/asterisk/res_odbc.h <span style="color: grey">(348047)</span></li>
<li>/branches/1.8/res/res_odbc.c <span style="color: grey">(348047)</span></li>
</ul>
<p><a href="https://reviewboard.asterisk.org/r/1622/diff/" style="margin-left: 3em;">View Diff</a></p>
</td>
</tr>
</table>
</div>
</body>
</html>