Merge pull request #113 from TitanSnow/root

privilege manage (escalation & degradation) when running as root

4 files changed, 140 insertions, 16 deletions

diff --git a/xmake/core/base/os.lua b/xmake/core/base/os.lua
index 02d96ad7e..ea6d3a9b0 100644
--- a/xmake/core/base/os.lua
+++ b/xmake/core/base/os.lua
@@ -34,6 +34,7 @@ local string    = require("base/string")
 
 -- save original interfaces
 os._uid         = os._uid or os.uid
+os._gid         = os._gid or os.gid
 os._mkdir       = os._mkdir or os.mkdir
 os._rmdir       = os._rmdir or os.rmdir
 os._tmpdir      = os._tmpdir or os.tmpdir
@@ -627,30 +628,32 @@ function os.nuldev()
 end
 
 -- get uid
-function os.uid()
-
-    -- get it from cache first
-    if os._UID then
-        return os._UID
-    end
-
+function os.uid(...)
     -- get uid
     os._UID = {}
     if os._uid then
-        os._UID = os._uid() or {}
+        os._UID = os._uid(...) or {}
     end
 
     -- ok?
     return os._UID
 end
 
+-- get gid
+function os.gid(...)
+    -- get gid
+    os._GID = {}
+    if os._gid then
+        os._GID = os._gid(...) or {}
+    end
+
+    -- ok?
+    return os._GID
+end
+
 -- check run command as root
 function os.isroot()
-
-    -- get it from cache
-    if os._ISROOT ~= nil then
-        return os._ISROOT
-    end
+    os._ISROOT = nil
 
     -- check it
     if os.uid().euid == 0 then
diff --git a/xmake/core/base/privilege.lua b/xmake/core/base/privilege.lua
new file mode 100644
index 000000000..275a7e7b5
--- /dev/null
+++ b/xmake/core/base/privilege.lua
@@ -0,0 +1,92 @@
+--!The Make-like Build Utility based on Lua
+--
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+-- Copyright (C) 2015 - 2017, TBOOX Open Source Group.
+--
+-- @author      TitanSnow
+-- @file        privilege.lua
+--
+
+-- define module
+local privilege = privilege or {}
+
+-- load modules
+local os = require("base/os")
+
+-- store privilege
+function privilege.store()
+    -- check if root
+    if not os.isroot() then
+        return false
+    end
+
+    -- find projectdir's owner
+    local projectdir = xmake._PROJECT_DIR
+    assert(projectdir)
+    local owner = os.getown(projectdir)
+    if not owner then
+        -- fallback to current dir
+        owner = os.getown(".")
+        if not owner then
+            return false
+        end
+    end
+
+    -- set gid
+    if os.gid(owner.gid).errno ~= 0 then
+        return false
+    end
+
+    -- set uid
+    if os.uid({["ruid"] = owner.uid}).errno ~= 0 or os.uid({["euid"] = owner.uid}).errno ~= 0 then
+        return false
+    end
+
+    -- set flag
+    privilege._HAS_PRIVILEGE = true
+
+    -- ok
+    return true
+end
+
+-- check if has stored privilege
+function privilege.has()
+    return privilege._HAS_PRIVILEGE or false
+end
+
+function privilege.get()
+    -- has?
+    if privilege._HAS_PRIVILEGE ~= true then
+        return false
+    end
+
+    -- set uid
+    if os.uid({["euid"] = 0}).errno ~= 0 or os.uid({["ruid"] = 0}).errno ~= 0 then
+        return false
+    end
+
+    -- set gid
+    if os.gid(0).errno ~= 0 then
+        return false
+    end
+
+    return true
+end
+
+-- return module
+return privilege
diff --git a/xmake/core/main.lua b/xmake/core/main.lua
index b4ca6afab..cda338294 100644
--- a/xmake/core/main.lua
+++ b/xmake/core/main.lua
@@ -32,6 +32,7 @@ local utils         = require("base/utils")
 local option        = require("base/option")
 local profiler      = require("base/profiler")
 local deprecated    = require("base/deprecated")
+local privilege     = require("base/privilege")
 local task          = require("project/task")
 local history       = require("project/history")
 
@@ -143,12 +144,14 @@ function main.done()
     -- check run command as root
     if not option.get("root") then
         if os.isroot() then
-            utils.error([[Running xmake as root is extremely dangerous and no longer supported.
+            if not privilege.store() or os.isroot() then
+                utils.error([[Running xmake as root is extremely dangerous and no longer supported.
 As xmake does not drop privileges on installation you would be giving all
 build scripts full access to your system. 
 Or you can add `--root` option to allow run as root temporarily.
-            ]])
-            return -1
+                ]])
+                return -1
+            end
         end
     end
 
diff --git a/xmake/core/sandbox/modules/import/core/base/privilege.lua b/xmake/core/sandbox/modules/import/core/base/privilege.lua
new file mode 100644
index 000000000..8f94cdb79
--- /dev/null
+++ b/xmake/core/sandbox/modules/import/core/base/privilege.lua
@@ -0,0 +1,26 @@
+--!The Make-like Build Utility based on Lua
+--
+-- Licensed to the Apache Software Foundation (ASF) under one
+-- or more contributor license agreements.  See the NOTICE file
+-- distributed with this work for additional information
+-- regarding copyright ownership.  The ASF licenses this file
+-- to you under the Apache License, Version 2.0 (the
+-- "License"); you may not use this file except in compliance
+-- with the License.  You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+-- Copyright (C) 2015 - 2017, TBOOX Open Source Group.
+--
+-- @author      TitanSnow
+-- @file        privilege.lua
+--
+
+-- return module
+return require("base/privilege")