Add function fs.is_superuser()

For environments other than UNIX, this will return false.

Suggested by @hishamhm.

4 files changed, 14 insertions, 2 deletions

diff --git a/src/luarocks/cmd.lua b/src/luarocks/cmd.lua
index 9255cff8..bc965af4 100644
--- a/src/luarocks/cmd.lua
+++ b/src/luarocks/cmd.lua
@@ -85,7 +85,7 @@ do
             replace_tree(args, root_dir)
          end
       elseif args["local"] then
-         if os.getenv("USER") == "root" then
+         if fs.is_superuser() then
             return nil, "The --local flag is meant for operating in a user's home directory.\n"..
                "You are running as a superuser, which is intended for system-wide operation.\n"..
                "To force using the superuser's home, use --tree explicitly."
@@ -642,7 +642,7 @@ function cmd.run_command(description, commands, external_namespace, ...)
    end
 
    -- if running as superuser, use system cache dir
-   if os.getenv("USER") == "root" then
+   if fs.is_superuser() then
       cfg.local_cache = dir.path(fs.system_cache_dir(), "luarocks")
    end
 
diff --git a/src/luarocks/fs/lua.lua b/src/luarocks/fs/lua.lua
index 0e98449a..6bd80485 100644
--- a/src/luarocks/fs/lua.lua
+++ b/src/luarocks/fs/lua.lua
@@ -1034,6 +1034,10 @@ function fs_lua.current_user()
    return posix.getpwuid(posix.geteuid()).pw_name
 end
 
+function fs_lua.is_superuser()
+   return false
+end
+
 -- This call is not available on all systems, see #677
 if posix.mkdtemp then
 
diff --git a/src/luarocks/fs/unix.lua b/src/luarocks/fs/unix.lua
index d5b36127..2c66eaa3 100644
--- a/src/luarocks/fs/unix.lua
+++ b/src/luarocks/fs/unix.lua
@@ -179,6 +179,10 @@ function unix.current_user()
    return os.getenv("USER")
 end
 
+function unix.is_superuser()
+   return os.getenv("USER") == "root"
+end
+
 function unix.export_cmd(var, val)
    return ("export %s='%s'"):format(var, val)
 end
diff --git a/src/luarocks/fs/win32.lua b/src/luarocks/fs/win32.lua
index 49de8e97..6d869d99 100644
--- a/src/luarocks/fs/win32.lua
+++ b/src/luarocks/fs/win32.lua
@@ -351,6 +351,10 @@ function win32.current_user()
    return os.getenv("USERNAME")
 end
 
+function win32.is_superuser()
+   return false
+end
+
 function win32.export_cmd(var, val)
    return ("SET %s=%s"):format(var, val)
 end