forked from dan/liminix
Daniel Barlow
49d1703428
When s6-rc stops a service, it also stops everything that depends on it. but when it starts a service it starts only that service, so we have to go through the other services depending on it and figure out if they should be started too.
78 lines
2.4 KiB
Fennel
78 lines
2.4 KiB
Fennel
(local { : assoc : system : dirname } (require :anoia))
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(local { : mktree : rmtree : symlink } (require :anoia.fs))
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(local { : AF_LOCAL : SOCK_STREAM } (require :anoia.net.constants))
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(local ll (require :lualinux))
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(local { : view } (require :fennel))
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(fn parse-args [args]
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(match args
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["-s" service & rest] (assoc (parse-args rest) :service service)
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["-n" path & rest] (assoc (parse-args rest) :linkname path)
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matches { :matches (table.concat matches " ") }
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_ nil))
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(fn %% [fmt ...] (string.format fmt ...))
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(var up :unknown)
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(fn start-service [devname linkname service]
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(match (if linkname (symlink (.. "/dev/" devname) linkname) true)
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ok (pcall system (%% "s6-rc-up-tree %q" service))
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(nil err) false))
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(fn stop-service [linkname service]
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(match (pcall system (%% "s6-rc -b -d change %q" service))
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ok (if linkname (os.remove linkname) true)
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(nil err) false))
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(fn toggle-service [devname linkname service wanted?]
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(when (not (= up wanted?))
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(set up
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(if wanted?
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(start-service devname linkname service)
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(not (stop-service linkname service))))))
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(fn parse-uevent [s]
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(when s
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(let [(nl nxt) (string.find s "\0" 1 true)]
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(collect [k v (string.gmatch
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(string.sub s (+ 1 nxt))
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"(%g-)=(%g+)")]
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(k:lower) v))))
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(fn run-with-fh [fh args]
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(set up :unknown)
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(let [parameters
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(assert (parse-args args) (.. "can't parse args: " (table.concat args " ")))]
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(when parameters.linkname (mktree (dirname parameters.linkname)))
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(var finished? false)
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(print "registering for events" (fh:write parameters.matches))
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(while (not finished?)
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(let [e (parse-uevent (fh:read))]
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(when e
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(let [wanted? (. {:add true :change true} e.action)]
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(toggle-service e.devname parameters.linkname parameters.service wanted?)))
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(set finished? (= e nil))
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))))
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(fn unix-connect [pathname]
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(let [addr (string.pack "=Hz" AF_LOCAL pathname)]
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(match (ll.socket AF_LOCAL SOCK_STREAM 0)
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sock (doto sock (ll.connect addr))
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(nil err) (error err))))
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(fn run [args]
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(let [fd (assert (unix-connect "/run/devout.sock"))
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devout {
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:read #(ll.read fd)
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:write #(ll.write fd $2)
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:close #(ll.close fd)
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}]
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(run-with-fh devout arg)))
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{ : run : run-with-fh }
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