Improve error checking in ownership check.

See #664.

4 files changed, 23 insertions, 7 deletions

diff --git a/src/luarocks/command_line.lua b/src/luarocks/command_line.lua
index 528ca068..6a1cc519 100644
--- a/src/luarocks/command_line.lua
+++ b/src/luarocks/command_line.lua
@@ -40,6 +40,18 @@ local function replace_tree(flags, tree)
    path.use_tree(tree)
 end
 
+local function is_ownership_ok(directory)
+   local me = fs.current_user()
+   for _ = 1,3 do -- try up to grandparent
+      local owner = fs.attributes(directory, "owner")
+      if owner then
+         return owner == me
+      end
+      directory = dir.dir_name(directory)
+   end
+   return false
+end
+
 --- Main command-line processor.
 -- Parses input arguments and calls the appropriate driver function
 -- to execute the action requested on the command-line, forwarding
@@ -182,8 +194,7 @@ function command_line.run_command(...)
       die("Current directory does not exist. Please run LuaRocks from an existing directory.")
    end
 
-   if fs.attributes(cfg.local_cache, "owner") ~= fs.current_user() or
-      fs.attributes(dir.dir_name(cfg.local_cache), "owner") ~= fs.current_user() then
+   if not is_ownership_ok(cfg.local_cache) then
       util.warning("The directory '" .. cfg.local_cache .. "' or its parent directory "..
                    "is not owned by the current user and the cache has been disabled. "..
                    "Please check the permissions and owner of that directory. "..
diff --git a/src/luarocks/fs/lua.lua b/src/luarocks/fs/lua.lua
index a14303e1..54da4afd 100644
--- a/src/luarocks/fs/lua.lua
+++ b/src/luarocks/fs/lua.lua
@@ -760,11 +760,13 @@ end
 
 function fs_lua.attributes(file, attrtype)
    if attrtype == "permissions" then
-      return posix.stat(file, "mode")
+      return posix.stat(file, "mode") or nil
    elseif attrtype == "owner" then
-      return posix.getpwuid(posix.stat(file, "uid")).pw_name
+      local uid = posix.stat(file, "uid")
+      if not uid then return nil end
+      return posix.getpwuid(uid).pw_name or nil
    else
-      return ""
+      return nil
    end
 end
 
diff --git a/src/luarocks/fs/unix/tools.lua b/src/luarocks/fs/unix/tools.lua
index e1b28b19..b2ace3b1 100644
--- a/src/luarocks/fs/unix/tools.lua
+++ b/src/luarocks/fs/unix/tools.lua
@@ -204,9 +204,12 @@ function tools.attributes(filename, attrtype)
    local flag = ((attrtype == "permissions") and vars.STATPERMFLAG)
              or ((attrtype == "owner") and vars.STATOWNERFLAG)
    if not flag then return "" end
-   local pipe = io.popen(vars.STAT.." "..flag.." "..fs.Q(filename))
+   local pipe = io.popen(fs.quiet_stderr(vars.STAT.." "..flag.." "..fs.Q(filename)))
    local ret = pipe:read("*l")
    pipe:close()
+   if ret == "" then
+      return nil
+   end
    return ret
 end
 
diff --git a/src/luarocks/fs/win32.lua b/src/luarocks/fs/win32.lua
index e2b37778..19c603dc 100644
--- a/src/luarocks/fs/win32.lua
+++ b/src/luarocks/fs/win32.lua
@@ -197,7 +197,7 @@ function win32.attributes(filename, attrtype)
    elseif attrtype == "owner" then
       return os.getenv("USERNAME") -- FIXME popen_read('powershell -Command "& {(get-acl '..filename..').owner}"'):gsub("^[^\\]*\\", "")
    end
-   return ""
+   return nil
 end
 
 --- Move a file on top of the other.