util.datamanager: Use pposix.fallocate() to make sure appends succeed. Also add a...

diff --git a/util/datamanager.lua b/util/datamanager.lua
index 23a2d74f187ef24b697107dc187ed9eae06c9ab8..29a5b994cfc413f512c61cbee181d33e16546e3a 100644 (file)
--- a/util/datamanager.lua
+++ b/util/datamanager.lua
@@ -21,17 +21,33 @@ local next = next;
 local t_insert = table.insert;
 local append = require "util.serialization".append;
 local envloadfile = require"util.envload".envloadfile;
+local serialize = require "util.serialization".serialize;
 local path_separator = assert ( package.config:match ( "^([^\n]+)" ) , "package.config not in standard form" ) -- Extract directory seperator from package.config (an undocumented string that comes with lua)
 local lfs = require "lfs";
 local prosody = prosody;
 local raw_mkdir;
+local fallocate;
 
 if prosody.platform == "posix" then
        raw_mkdir = require "util.pposix".mkdir; -- Doesn't trample on umask
+       fallocate = require "util.pposix".fallocate;
 else
        raw_mkdir = lfs.mkdir;
 end
 
+if not fallocate then -- Fallback
+       function fallocate(f, offset, len)
+               -- This assumes that current position == offset
+               local fake_data = (" "):rep(len);
+               local ok, msg = f:write(fake_data);
+               if not ok then
+                       return ok, msg;
+               end
+               f:seek(offset);
+               return true;
+       end
+end
+
 module "datamanager"
 
 ---- utils -----
@@ -165,14 +181,21 @@ function list_append(username, host, datastore, data)
        if not data then return; end
        if callback(username, host, datastore) == false then return true; end
        -- save the datastore
-       local f, msg = io_open(getpath(username, host, datastore, "list", true), "a+");
+       local f, msg = io_open(getpath(username, host, datastore, "list", true), "a");
        if not f then
                log("error", "Unable to write to %s storage ('%s') for user: %s@%s", datastore, msg, username or "nil", host or "nil");
                return;
        end
-       f:write("item(");
-       append(f, data);
-       f:write(");\n");
+       local data = "item(" ..  serialize(data) .. ");\n";
+       local pos = f:seek("end");
+       local ok, msg = fallocate(f, pos, #data);
+       f:seek("set", pos);
+       if ok then
+               f:write(data);
+       else
+               log("error", "Unable to write to %s storage ('%s') for user: %s@%s", datastore, msg, username or "nil", host or "nil");
+               return ok, msg;
+       end
        f:close();
        return true;
 end