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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>
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<p style="margin-top: 0;">On December 14th, 2011, 11:08 a.m., <b>Tilghman Lesher</b> wrote:</p>
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<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>
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(Diff revision 1)
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<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>
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<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>
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<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>
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<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;">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>
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<p>- Tilghman</p>
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<p>On December 14th, 2011, 3:01 a.m., wdoekes wrote:</p>
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<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>
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<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>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<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>
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<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>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<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>
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<p><a href="https://reviewboard.asterisk.org/r/1622/diff/" style="margin-left: 3em;">View Diff</a></p>
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