68 lines
2.1 KiB
Markdown
68 lines
2.1 KiB
Markdown
You know, gpm is a hack.
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The idea of gpm2 is to be a nicer hack:
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* Support multiple mice
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* Do not draw stuff, but write gpm2 client to do so (os/terminal specific stuff)
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* Usable under different OS
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* Allow hotplugging of mice (i.e. gpm2d can run without any mice at startup)
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## Trying out gpm2
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gpm2 is in its early design stage, but can so far display movement of a
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ps/2 compatible mouse.
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git clone git://git.schottelius.org/gpm
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cd gpm
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git checkout -b gpm2 origin/gpm-2-hack
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./gpm2hack.sh /dev/input/mice
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# move the mouse
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# press enter key to end demonstration
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If you do not see mouse movement deltas, either your mouse in connected
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to a different device or you probably do not have permissions to communicate
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with it.
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## Development
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### Names
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* gpm2_*: Stuff that may appear in a library
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* *: Stuff that will only be used in the gpm2 main process
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## Mouse protocols
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Protocols in gpm2 are *not* part of the main system. Instead,
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each protocol is implemented in its own binary, which is called
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from gpm2d.
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This prevents to create just another ugly "static" struct array
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or the need to dlopen() and friends.
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### Implementing a protocol
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If you want to implement a mouse protocol, there are some things
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to take care of:
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* You have a free choice of the programming language
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* gpm2d will exec() gpm2-<protocol> from its path,
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* gpm2d will connect stdin stdout of gpm2-<protocol> to the device file
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* gpm2d will connect stderr to gpm2d, so gpm2-<protocol> can send messages
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* gpm2d can drop priviliges to a specific, non-root user
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* gpm2d will send SIGTERM to gpm2-<protocol> to signal normal termination
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* gpm2-<protocol> should close the file and exit
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* gpm2-<protocol> reports about events via stderr
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### Reading options from gpm2d
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If at some point gpm2d needs to pass protocol options to the protocol
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handler, they can be found in GPM2_PROTO_OPTS.
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## Client protocols
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Clients for gpm2 do not need to be c programs, but can be of any kind.
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The communication is a simple ASCII stream.
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### Connect to gpm2d
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Clients need to open /var/run/gpm2/gpm2d.sock to connect to gpm2d.
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