1ba48868f6
There is a lock order violation when a server force disconnects it's clients while sending a final message to it (or concurrent close, or probably others). The entry points are channelStateChange() and operation send(). Fix is not to hold the channel mutex when destroy()ing operations. epics::pvAccess::ServerChannelRPCRequesterImpl::destroy locks RPC requester mutex epics::pvAccess::ServerChannel::destroy locks channel mutex epics::pvAccess::ServerChannelRequesterImpl::channelStateChange epics::pvAccess::ServerChannel::unregisterRequest locks channel mutex epics::pvAccess::ServerChannelRPCRequesterImpl::destroy locks RPC requester mutex epics::pvAccess::ServerChannelRPCRequesterImpl::send
pvAccessCPP
pvAccess is a computer communications protocol for control systems, and is a central component of the EPICS software toolkit. pvAccessCPP is the name of the software module which contains the C++ implementation of pvAccess.
Further Info
Consult the documents in the documentation directory, in particular
- pvAccessCPP.html
- RELEASE_NOTES.md
Also see the EPICS Version 4 website
Prerequisites
The pvAccessCPP requires recent versions of the following software:
- EPICS Base (v3.14.12.3 or later)
- EPICS4 pvCommonCPP (4.1.1 or later)
- EPICS4 pvDataCPP (5.0.2 or later)
Building
Building uses the make utility and the EPICS base build system.
The build system needs the location of the prerequisites, e.g. by placing the lines of the form
PVCOMMON = /home/install/epicsV4/pvCommonCPP
PVDATA = /home/install/epicsV4/pvDataCPP
EPICS_BASE = /home/install/epics/base
pointing to the locations in a file called RELEASE.local in the configure directory or the parent directory of pvAccessCPP.
With this in place, to build type make
make
To perform a clean build type
make clean uninstall
To run the unit tests type
make runtests
For more information on the EPICS build system consult the Application Development guide.
Example Usage
This section describes how you can test and demo pvAccess.
A test server is shipped with pvAccessCPP. See the file pvAccessCPP/DEMO for examples of usage. To run the server, write a setup script like that above, and then use it prior to executing "runTestServer":
$ ./runTestServer
Starting pvAccess C++ test server...
VERSION : pvAccess Server v4.1.1
PROVIDER_NAMES : local
BEACON_ADDR_LIST :
AUTO_BEACON_ADDR_LIST : 1
BEACON_PERIOD : 15
BROADCAST_PORT : 5076
SERVER_PORT : 5075
RCV_BUFFER_SIZE : 16384
IGNORE_ADDR_LIST:
STATE : INITIALIZED
Then, another window, you can go through the demos in pvAccessCPP/DEMO. For example:
$ ./bin/$EPICS_HOST_ARCH/pvget testValue
testValue 0