src/patches/squid/squid-3.5-14119.patch

   1 ------------------------------------------------------------
   2 revno: 14119
   3 revision-id: squid3@treenet.co.nz-20161209015833-xm965d5l6u03qhew
   4 parent: squid3@treenet.co.nz-20161130233304-lk3q0bx8gn5l3l85
   5 fixes bug: http://bugs.squid-cache.org/show_bug.cgi?id=4174
   6 author: Christos Tsantilas <chtsanti@users.sourceforge.net>
   7 committer: Amos Jeffries <squid3@treenet.co.nz>
   8 branch nick: 3.5
   9 timestamp: Fri 2016-12-09 14:58:33 +1300
  10 message:
  11   Bug 4174 partial: fix Write.cc:41 "!ccb->active()" assertion.
  12
  13   The following sequence of events triggers this assertion:
  14     - The server sends an 1xx control message.
  15     - http.cc schedules ConnStateData::sendControlMsg call.
  16     - Before sendControlMsg is fired, http.cc detects an error (e.g., I/O
  17       error or timeout) and starts writing the reply to the user.
  18     - The ConnStateData::sendControlMsg is fired, starts writing 1xx, and
  19       hits the "no concurrent writes" assertion.
  20
  21   We could only reproduce this sequence in the lab after changing Squid
  22   code to trigger a timeout at the right moment, but the sequence looks
  23   plausible. Other event sequences might result in the same outcome.
  24
  25   To avoid concurrent writes, Squid now drops the control message if
  26   Http::One::Server detects that a reply is already being written. Also,
  27   ConnStateData delays reply writing until a pending control message write
  28   has been completed.
  29
  30   This is a Measurement Factory project.
  31 ------------------------------------------------------------
  32 # Bazaar merge directive format 2 (Bazaar 0.90)
  33 # revision_id: squid3@treenet.co.nz-20161209015833-xm965d5l6u03qhew
  34 # target_branch: http://bzr.squid-cache.org/bzr/squid3/3.5
  35 # testament_sha1: 103c6fc1fa45d78ba7f9e85ab3d89fff898ee762
  36 # timestamp: 2016-12-09 02:51:06 +0000
  37 # source_branch: http://bzr.squid-cache.org/bzr/squid3/3.5
  38 # base_revision_id: squid3@treenet.co.nz-20161130233304-\
  39 #   lk3q0bx8gn5l3l85
  40 #
  41 # Begin patch
  42 === modified file 'src/client_side.cc'
  43 --- src/client_side.cc  2016-09-23 20:49:24 +0000
  44 +++ src/client_side.cc  2016-12-09 01:58:33 +0000
  45 @@ -340,7 +340,21 @@
  46      AsyncCall::Pointer call = commCbCall(33, 5, "ClientSocketContext::wroteControlMsg",
  47                                           CommIoCbPtrFun(&WroteControlMsg, this));
  48
  49 -    getConn()->writeControlMsgAndCall(this, rep.getRaw(), call);
  50 +    if (!getConn()->writeControlMsgAndCall(this, rep.getRaw(), call)) {
  51 +        // but still inform the caller (so it may resume its operation)
  52 +        doneWithControlMsg();
  53 +    }
  54 +}
  55 +
  56 +void
  57 +ClientSocketContext::doneWithControlMsg()
  58 +{
  59 +    ScheduleCallHere(cbControlMsgSent);
  60 +    cbControlMsgSent = NULL;
  61 +
  62 +    debugs(33, 3, clientConnection << ": calling PushDeferredIfNeeded after control msg wrote");
  63 +    ClientSocketContextPushDeferredIfNeeded(this, getConn());
  64 +
  65  }
  66
  67  /// called when we wrote the 1xx response
  68 @@ -351,7 +365,7 @@
  69          return;
  70
  71      if (errflag == Comm::OK) {
  72 -        ScheduleCallHere(cbControlMsgSent);
  73 +        doneWithControlMsg();
  74          return;
  75      }
  76
  77 @@ -1455,6 +1469,8 @@
  78
  79      if (context != http->getConn()->getCurrentContext())
  80          context->deferRecipientForLater(node, rep, receivedData);
  81 +    else if (context->controlMsgIsPending())
  82 +        context->deferRecipientForLater(node, rep, receivedData);
  83      else
  84          http->getConn()->handleReply(rep, receivedData);
  85
  86
  87 === modified file 'src/client_side.h'
  88 --- src/client_side.h   2016-06-18 13:36:07 +0000
  89 +++ src/client_side.h   2016-12-09 01:58:33 +0000
  90 @@ -129,9 +129,13 @@
  91      /// starts writing 1xx control message to the client
  92      void writeControlMsg(HttpControlMsg &msg);
  93
  94 +    /// true if 1xx to the user is pending
  95 +    bool controlMsgIsPending() {return cbControlMsgSent != NULL;}
  96 +
  97  protected:
  98      static IOCB WroteControlMsg;
  99      void wroteControlMsg(const Comm::ConnectionPointer &conn, char *bufnotused, size_t size, Comm::Flag errflag, int xerrno);
 100 +    void doneWithControlMsg();
 101
 102  private:
 103      void prepareReply(HttpReply * rep);
 104 @@ -387,7 +391,7 @@
 105      void connectionTag(const char *aTag) { connectionTag_ = aTag; }
 106
 107      /// handle a control message received by context from a peer and call back
 108 -    virtual void writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call) = 0;
 109 +    virtual bool writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call) = 0;
 110
 111      /// ClientStream calls this to supply response header (once) and data
 112      /// for the current ClientSocketContext.
 113
 114 === modified file 'src/servers/FtpServer.cc'
 115 --- src/servers/FtpServer.cc    2016-06-30 21:09:12 +0000
 116 +++ src/servers/FtpServer.cc    2016-12-09 01:58:33 +0000
 117 @@ -1152,12 +1152,13 @@
 118      writeErrorReply(reply, 451);
 119  }
 120
 121 -void
 122 +bool
 123  Ftp::Server::writeControlMsgAndCall(ClientSocketContext *context, HttpReply *reply, AsyncCall::Pointer &call)
 124  {
 125      // the caller guarantees that we are dealing with the current context only
 126      // the caller should also make sure reply->header.has(HDR_FTP_STATUS)
 127      writeForwardedReplyAndCall(reply, call);
 128 +    return true;
 129  }
 130
 131  void
 132
 133 === modified file 'src/servers/FtpServer.h'
 134 --- src/servers/FtpServer.h     2016-03-15 18:14:15 +0000
 135 +++ src/servers/FtpServer.h     2016-12-09 01:58:33 +0000
 136 @@ -94,7 +94,7 @@
 137      virtual void clientPinnedConnectionClosed(const CommCloseCbParams &io);
 138      virtual void handleReply(HttpReply *header, StoreIOBuffer receivedData);
 139      virtual int pipelinePrefetchMax() const;
 140 -    virtual void writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call);
 141 +    virtual bool writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call);
 142      virtual time_t idleTimeout() const;
 143
 144      /* BodyPipe API */
 145
 146 === modified file 'src/servers/HttpServer.cc'
 147 --- src/servers/HttpServer.cc   2016-01-01 00:14:27 +0000
 148 +++ src/servers/HttpServer.cc   2016-12-09 01:58:33 +0000
 149 @@ -35,7 +35,7 @@
 150      virtual ClientSocketContext *parseOneRequest(Http::ProtocolVersion &ver);
 151      virtual void processParsedRequest(ClientSocketContext *context, const Http::ProtocolVersion &ver);
 152      virtual void handleReply(HttpReply *rep, StoreIOBuffer receivedData);
 153 -    virtual void writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call);
 154 +    virtual bool writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call);
 155      virtual time_t idleTimeout() const;
 156
 157      /* BodyPipe API */
 158 @@ -167,9 +167,16 @@
 159      context->sendStartOfMessage(rep, receivedData);
 160  }
 161
 162 -void
 163 +bool
 164  Http::Server::writeControlMsgAndCall(ClientSocketContext *context, HttpReply *rep, AsyncCall::Pointer &call)
 165  {
 166 +    // Ignore this late control message if we have started sending a
 167 +    // reply to the user already (e.g., after an error).
 168 +    if (context->reply) {
 169 +        debugs(11, 2, "drop 1xx made late by " << context->reply);
 170 +        return false;
 171 +    }
 172 +
 173      // apply selected clientReplyContext::buildReplyHeader() mods
 174      // it is not clear what headers are required for control messages
 175      rep->header.removeHopByHopEntries();
 176 @@ -184,6 +191,7 @@
 177      Comm::Write(context->clientConnection, mb, call);
 178
 179      delete mb;
 180 +    return true;
 181  }
 182
 183  ConnStateData *
 184