move multishell functionality to kernel

sys/kernel.lua

@@ -0,0 +1,83 @@
+local sandboxEnv = setmetatable({ }, { __index = _G })
+for k,v in pairs(_ENV) do
+  sandboxEnv[k] = v
+end
+
+_G.requireInjector()
+
+local Util = require('util')
+
+_G.kernel = {
+  hooks = { }
+}
+
+local kernel = _G.kernel
+local fs     = _G.fs
+local shell  = _ENV.shell
+
+-- user environment
+if not fs.exists('usr/apps') then
+  fs.makeDir('usr/apps')
+end
+if not fs.exists('usr/autorun') then
+  fs.makeDir('usr/autorun')
+end
+if not fs.exists('usr/etc/fstab') then
+  Util.writeFile('usr/etc/fstab', 'usr gitfs kepler155c/opus-apps/develop')
+end
+if not fs.exists('usr/config/shell') then
+  Util.writeTable('usr/config/shell', {
+    aliases  = shell.aliases(),
+    path     = 'usr/apps:sys/apps:' .. shell.path(),
+    lua_path = '/sys/apis:/usr/apis',
+  })
+end
+
+-- shell environment
+local config = Util.readTable('usr/config/shell')
+if config.aliases then
+  for k in pairs(shell.aliases()) do
+    shell.clearAlias(k)
+  end
+  for k,v in pairs(config.aliases) do
+    shell.setAlias(k, v)
+  end
+end
+shell.setPath(config.path)
+_G.LUA_PATH = config.lua_path
+
+-- any function that runs in a kernel hook does not run in
+-- a separate coroutine or have a window. an error in a hook
+-- function will crash the system.
+function kernel.hook(event, fn)
+  if type(event) == 'table' then
+    for _,v in pairs(event) do
+      kernel.hook(v, fn)
+    end
+  else
+    if not kernel.hooks[event] then
+      kernel.hooks[event] = { }
+    end
+    table.insert(kernel.hooks[event], fn)
+  end
+end
+
+-- you can only unhook from within the function that hooked
+function kernel.unhook(event, fn)
+  local eventHooks = kernel.hooks[event]
+  if eventHooks then
+    Util.removeByValue(eventHooks, fn)
+    if #eventHooks == 0 then
+      kernel.hooks[event] = nil
+    end
+  end
+end
+
+-- extensions
+local dir = 'sys/extensions'
+for _,file in ipairs(fs.list(dir)) do
+  local s, m = Util.run(sandboxEnv, 'sys/apps/shell', fs.combine(dir, file))
+  if not s then
+    error(m)
+  end
+end