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This is an automatically generated e-mail. To reply, visit:
<a href="https://reviewboard.asterisk.org/r/1353/">https://reviewboard.asterisk.org/r/1353/</a>
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<p style="margin-top: 0;">On August 25th, 2011, 4:28 p.m., <b>rmudgett</b> wrote:</p>
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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;">I don't think this approach is going to work either.</pre>
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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;">It works, but is it the right approach?</pre>
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<p style="margin-top: 0;">On August 25th, 2011, 4:28 p.m., <b>rmudgett</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/1353/diff/2/?file=18593#file18593line1202" style="color: black; font-weight: bold; text-decoration: underline;">trunk/channels/chan_local.c</a>
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(Diff revision 2)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static struct ast_channel *local_request(const char *type, struct ast_format_cap *cap, const struct ast_channel *requestor, void *data, int *cause)</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">if</span> <span class="p">(</span><span class="n">requestor</span><span class="o">-></span><span class="n">parent</span><span class="p">)</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">p</span><span class="o">-></span><span class="n">owner</span><span class="o">-></span><span class="n">parent</span> <span class="o">=</span> <span class="n">p</span><span class="o">-></span><span class="n">chan</span><span class="o">-></span><span class="n">parent</span> <span class="o">=</span> <span class="p">(</span><span class="k">struct</span> <span class="n">ast_channel</span> <span class="o">*</span><span class="p">)</span> <span class="n">requestor</span><span class="o">-></span><span class="n">parent</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="p">}</span> <span class="k">else</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">p</span><span class="o">-></span><span class="n">owner</span><span class="o">-></span><span class="n">parent</span> <span class="o">=</span> <span class="n">p</span><span class="o">-></span><span class="n">chan</span><span class="o">-></span><span class="n">parent</span> <span class="o">=</span> <span class="p">(</span><span class="k">struct</span> <span class="n">ast_channel</span> <span class="o">*</span><span class="p">)</span> <span class="n">requestor</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="p">}</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;">This will need to be done for all channel drivers.</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;">I tried to do this in main/channel.c:ast_request() which would then cover all channels, but for the life of me get to the pvt. </pre>
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<p style="margin-top: 0;">On August 25th, 2011, 4:28 p.m., <b>rmudgett</b> wrote:</p>
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<a href="https://reviewboard.asterisk.org/r/1353/diff/2/?file=18596#file18596line6956" style="color: black; font-weight: bold; text-decoration: underline;">trunk/main/features.c</a>
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(Diff revision 2)
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<td colspan="4"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int manager_park(struct mansession *s, const struct message *m)</pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">if</span> <span class="p">(</span><span class="n">chan</span><span class="o">-></span><span class="n">parent</span><span class="p">)</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">parent</span> <span class="o">=</span> <span class="n">chan</span><span class="o">-></span><span class="n">parent</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">while</span> <span class="p">(</span><span class="n">parent</span><span class="o">-></span><span class="n">parent</span><span class="p">)</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="n">parent</span> <span class="o">=</span> <span class="n">parent</span><span class="o">-></span><span class="n">parent</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="p">}</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">if</span> <span class="p">(</span> <span class="o">!</span><span class="n">ast_channel_datastore_find</span><span class="p">(</span><span class="n">parent</span><span class="p">,</span> <span class="o">&</span><span class="n">pickup_active</span><span class="p">,</span> <span class="nb">NULL</span><span class="p">))</span> <span class="p">{</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">return</span> <span class="mi">1</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="p">}</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="k">return</span> <span class="mi">0</span><span class="p">;</span></pre></td>
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<td bgcolor="#c5ffc4" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "> <span class="p">}</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;">Walking this list is dangerous since the list is hopping through ast_channel structs that you don't have the locks on.
The call to ast_channel_datastore_find() must be called with that channel locked.</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;">Understand regarding locks, first cut.
Is there another way to find the head caller?
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<p>- Alec</p>
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<p>On August 25th, 2011, 7:19 a.m., Alec Davis wrote:</p>
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<div>Review request for Asterisk Developers and rmudgett.</div>
<div>By Alec Davis.</div>
<p style="color: grey;"><i>Updated Aug. 25, 2011, 7:19 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;">If ast_can_pickup() can pickup the target channel, it also needs to check that the originating parent channel isn't being picked up from one of the other spawned the calls.
Example dialplan below causes a segfault as ast-hangup removes the same channel as is being picked up.
How to crash it!
dial 801 from 1 phone.
from 2 phones simultaneously dial 800.
segfault!
exten => 801,1,NoOp(Local pickup debug: Ring Phones)
exten => 801,n,Dial(Local/823@en-phone&Local/824@en-phone)
exten => 800,1,NoOp(Local pickup: Pickup through Localchan call)
exten => 800,n,Dial(Local/824@en-pickup&Local/823@en-pickup)
[en-pickup]
exten => _[0-9*#]!, 1, PickupChan(Local/${EXTEN}@en-phone)
[en-phone]
exten => _[0-9*#]!, 1, Dial(SIP/gxp-${EXTEN},20,rwt)
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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;">Party A ring in which triggers off 2 internal localchan calls, as per 801 in the example dialplan.
Party B and Party C, attempt to pickup the same calls, using 800 in the example dialplan.
There is another senario thats not right, before even applying this patch.
Party A ring in, which again triggers 2 internal localchan calls as per 801 in dialplan.
Party B and Party C, use *8 to pickup. We then have a NULL OBJ message on screen, and an orpaned channel.
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<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-18222">ASTERISK-18222</a>,
<a href="https://issues.asterisk.org/jira/browse/ASTERISK-18273">ASTERISK-18273</a>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>trunk/channels/chan_local.c <span style="color: grey">(333199)</span></li>
<li>trunk/channels/chan_sip.c <span style="color: grey">(333199)</span></li>
<li>trunk/include/asterisk/channel.h <span style="color: grey">(333199)</span></li>
<li>trunk/main/features.c <span style="color: grey">(333199)</span></li>
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<p><a href="https://reviewboard.asterisk.org/r/1353/diff/" style="margin-left: 3em;">View Diff</a></p>
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