lsyncd/mantle/inotify.lua
Axel Kittenberger 902b2c77cd cleanups
2018-03-30 15:15:49 +02:00

298 lines
5.3 KiB
Lua

--
-- inotify.lua from Lsyncd -- the Live (Mirror) Syncing Demon
--
--
-- Interface to inotify core.
--
-- watches recursively subdirs and sends events.
-- All inotify specific implementation is enclosed here.
--
--
-- License: GPLv2 (see COPYING) or any later version
-- Authors: Axel Kittenberger <axkibe@gmail.com>
--
if lsyncd_version
then
print( 'Error, Lsyncd mantle already loaded' )
os.exit( -1 )
end
--
-- Returns the relative part of absolute path if it
-- begins with root
--
local function splitPath
(
path,
root
)
local rlen = #root
local sp = string.sub( path, 1, rlen )
if sp == root
then
return string.sub( path, rlen, -1 )
else
return nil
end
end
--
-- A list indexed by inotify watch descriptors yielding
-- the directories absolute paths.
--
local wdpaths = Counter.new( )
--
-- The same vice versa,
-- all watch descriptors by their absolute paths.
--
local pathwds = { }
--
-- A list indexed by syncs containing yielding
-- the root paths the syncs are interested in.
--
local syncRoots = { }
--
-- Stops watching a directory
--
local function removeWatch
(
path, -- absolute path to unwatch
core -- if false not actually send the unwatch to the kernel
-- ( used in moves which reuse the watch )
)
local wd = pathwds[ path ]
if not wd then return end
if core then core.inotify.rmwatch( wd ) end
wdpaths[ wd ] = nil
pathwds[ path ] = nil
end
--
-- Adds watches for a directory (optionally) including all subdirectories.
--
local function addWatch
(
path -- absolute path of directory to observe
)
log( 'Function', 'Inotify.addWatch( ', path, ' )' )
if not SyncMaster.concerns( path )
then
log( 'Inotify', 'not concerning "', path, '"')
return
end
-- registers the watch
local inotifyMode = ( uSettings and uSettings.inotifyMode ) or ''
local wd = core.inotify.addwatch( path, inotifyMode )
if wd < 0
then
log( 'Inotify', 'Unable to add watch "', path, '"' )
return
end
do
-- If this watch descriptor is registered already
-- the kernel reuses it since the old dir is gone.
local op = wdpaths[ wd ]
if op and op ~= path then pathwds[ op ] = nil end
end
pathwds[ path ] = wd
wdpaths[ wd ] = path
-- registers and adds watches for all subdirectories
local entries = readdir( path )
if not entries then return end
for dirname, isdir in pairs( entries )
do
if isdir then addWatch( path .. dirname .. '/' ) end
end
end
--
-- Adds a Sync to receive events.
--
local function addSync
(
sync, -- object to receive events.
rootdir -- root dir to watch
)
if syncRoots[ sync ]
then
error( 'duplicate sync in Inotify.addSync()' )
end
syncRoots[ sync ] = rootdir
addWatch( rootdir )
end
--
-- Called when an event has occured.
--
local function event
(
etype, -- 'Attrib', 'Modify', 'Create', 'Delete', 'Move'
wd, -- watch descriptor, matches core.inotifyadd()
isdir, -- true if filename is a directory
time, -- time of event
filename, -- string filename without path
wd2, -- watch descriptor for target if it's a Move
filename2 -- string filename without path of Move target
)
if isdir
then
filename = filename .. '/'
if filename2 then filename2 = filename2 .. '/' end
end
if filename2
then
log(
'Inotify',
'got event ', etype, ' ',
filename, '(', wd, ') to ',
filename2, '(', wd2 ,')'
)
else
log(
'Inotify',
'got event ', etype, ' ',
filename, '(', wd, ')'
)
end
-- looks up the watch descriptor id
local path = wdpaths[ wd ]
if path then path = path..filename end
local path2 = wd2 and wdpaths[ wd2 ]
if path2 and filename2 then path2 = path2..filename2 end
if not path and path2 and etype == 'Move'
then
log( 'Inotify', 'Move from deleted directory ', path2, ' becomes Create.' )
path = path2
path2 = nil
etype = 'Create'
end
if not path
then
-- this is normal in case of deleted subdirs
log( 'Inotify', 'event belongs to unknown watch descriptor.' )
return
end
for sync, root in pairs( syncRoots )
do repeat
local relative = splitPath( path, root )
local relative2 = nil
if path2 then relative2 = splitPath( path2, root ) end
if not relative and not relative2
then
-- sync is not interested in this dir
break -- continue
end
-- makes a copy of etype to possibly change it
local etyped = etype
if etyped == 'Move'
then
if not relative2
then
log(
'Normal',
'Transformed Move to Delete for ',
sync.config.name
)
etyped = 'Delete'
elseif not relative
then
relative = relative2
relative2 = nil
log(
'Normal',
'Transformed Move to Create for ',
sync.config.name
)
etyped = 'Create'
end
end
if isdir
then
if etyped == 'Create'
then
addWatch( path )
elseif etyped == 'Delete'
then
removeWatch( path, true )
elseif etyped == 'Move'
then
removeWatch( path, false )
addWatch( path2 )
end
end
sync:delay( etyped, time, relative, relative2 )
until true end
end
--
-- Writes a status report about inotify to a file descriptor
--
local function statusReport( f )
f:write( 'Inotify watching ', #wdpaths, ' directories\n' )
for wd, path in pairs( wdpaths )
do
f:write( ' ', wd, ': ', path, '\n' )
end
end
--
-- Exported interface.
--
Inotify =
{
addSync = addSync,
event = event,
statusReport = statusReport,
}