liblua: Accept + and e in io.popen mode

[rmoeller]

Summary

Our popen(3) accepts more than the historical "r" and "w" types. Define
the appropriate macro to provide a custom mode check accepting all valid
pipe types.

[rmoeller]

This enables io.popen() to invoke a command with a bidirectional pipe by passing "r+" or "r+e" as the mode. For example, calling "cxgbetool stdio" to set up multiple filter rules in one action requires both reading from and writing to the process:

#!/usr/libexec/flua     
                                   
local cxgbetool <const> = {}
cxgbetool.__index = cxgbetool
setmetatable(cxgbetool, cxgbetool)  
                                    
function cxgbetool.__call(class, nexus)            
        return setmetatable({nexus=nexus}, class)
end                                                                      
                                    
function cxgbetool:popen(cmdline, ...)                                   
        return io.popen(("cxgbetool %q %s"):format(self.nexus, cmdline), ...)
end                      
                                                                         
function cxgbetool:stdio()          
        return self:popen("stdio", "r+e")                                
end                                 
                                
function cxgbetool:filters(filters) 
        local p <close> = self:stdio()                    
        for i, rule in ipairs(filters) do
                p:read(1) -- consume the prompt                      
                p:write(("filter %d %s\n"):format(i, rule))
        end
end

-- snip --

local t5nex0 <const> = cxgbetool "t5nex0"

t5nex0:filters {
        pass { iport=0, matchtype=mask(0, 4), prio=1 },
        pass { iport=0, matchtype=6, prio=1 },
        switch { iport=0, eport=1, prio=1 },
        pass { iport=1, matchtype=mask(0, 4), prio=1 },
        pass { iport=1, matchtype=6, prio=1 },
        switch { iport=1, eport=0, prio=1 },
}
-- snip --

[rmoeller]

A question this brought up while looking into it: the lib/liblua/luaconf.h file seems stale and unused, and I wonder if it is similar for stand/liblua/luaconf.h? The build seems to be using contrib/lua/src/luaconf.h, which is the copy that actually includes this lib/liblua/luaconf.local.h file.

[kevans]

In D61175#1402545, @rmoeller wrote:

A question this brought up while looking into it: the lib/liblua/luaconf.h file seems stale and unused, and I wonder if it is similar for stand/liblua/luaconf.h? The build seems to be using contrib/lua/src/luaconf.h, which is the copy that actually includes this lib/liblua/luaconf.local.h file.

Yes, it's probably time to axe those; 8c784bb8cf36911b828652f0bf7e88f443abec50 is where @imp changed the model here.

[imp]

I think it is time to axe those too.