X-Git-Url: https://sipb.mit.edu/gitweb.cgi/ikiwiki.git/blobdiff_plain/d07c6b707da7c22d6b744b8cf50e306766e11ba9..41d13673c6aac2cf0e965d023835989edbe82c93:/doc/plugins/po.mdwn
diff --git a/doc/plugins/po.mdwn b/doc/plugins/po.mdwn
index 044a165b3..6a2409847 100644
--- a/doc/plugins/po.mdwn
+++ b/doc/plugins/po.mdwn
@@ -6,15 +6,17 @@ gettext, using [po4a](http://po4a.alioth.debian.org/).
It depends on the Perl `Locale::Po4a::Po` library (`apt-get install po4a`).
+[[!toc]]
+
Introduction
============
A language is chosen as the "master" one, and any other supported
language is a "slave" one.
-A page written in the "master" language is a "master" page, and is
-written in any supported format but PO. It does not have to be named
-a special way: migration from/to this plugin does not imply heavy
+A page written in the "master" language is a "master" page. It can be
+of any page type supported by ikiwiki, except `po`. It does not have to be
+named a special way: migration to this plugin does not imply any page
renaming work.
Example: `bla/page.mdwn` is a "master" Markdown page written in
@@ -22,7 +24,7 @@ English; if `usedirs` is enabled, it is rendered as
`bla/page/index.en.html`, else as `bla/page.en.html`.
Any translation of a "master" page into a "slave" language is called
-a "slave" page; it is written in the gettext PO format. PO is now
+a "slave" page; it is written in the gettext PO format. `po` is now
a page type supported by ikiwiki.
Example: `bla/page.fr.po` is the PO "message catalog" used to
@@ -33,7 +35,10 @@ rendered as `bla/page/index.fr.html`, else as `bla/page.fr.html`
Configuration
=============
-`po_master_language` is used to set the master language in
+Supported languages
+-------------------
+
+`po_master_language` is used to set the "master" language in
`ikiwiki.setup`, such as:
po_master_language => { 'code' => 'en', 'name' => 'English' }
@@ -53,67 +58,43 @@ The `po_translatable_pages` setting configures what pages are
translatable. It is a [[ikiwiki/PageSpec]], so you have lots of
control over what kind of pages are translatable.
-The `*.LL.po` translations files are anyway not considered as being
-translatable, so you don't need to worry about excluding them manually
-from this [[ikiwiki/PageSpec]].
+The `.po` files are not considered as being translatable, so you don't need to
+worry about excluding them explicitly from this [[ikiwiki/PageSpec]].
Internal links
--------------
-One can use the `po_link_to_` option in `ikiwiki.setup` to choose how
+The `po_link_to` option in `ikiwiki.setup` is used to decide how
internal links should be generated, depending on web server features
and site-specific preferences.
### Default linking behavior
If `po_link_to` is unset, or set to `default`, ikiwiki's default
-linking behavior is preserved: `\[[page]]` links to the master
+linking behavior is preserved: `\[[destpage]]` links to the master
language's page.
-### Link to negotiated language
-
-If `po_link_to` is set to `negotiated`, `\[[page]]` links to the
-negotiated preferred language, *i.e.* `foo/page/`.
-
-(In)compatibility notes:
-
-- `po_link_to => negotiated` provides no useful behavior if `usedirs`
- is disabled; this option combination is neither implemented nor
- allowed
-- `po_link_to => negotiated` provides no useful behavior if the web
- server does not support Content Negotiation
-
### Link to current language
-If `po_link_to` is set to `current` and the destination page is either
-a translatable page or a translation, `\[[page]]` links to the current
-page's language, *i.e.*:
+If `po_link_to` is set to `current`, `\[[destpage]]` links to the
+`destpage`'s version written in the current page's language, if
+available, *i.e.*:
-- `foo/page/index.LL.html` if `usedirs` is enabled
-- `foo/page.LL.html` if `usedirs` is disabled
+- `foo/destpage/index.LL.html` if `usedirs` is enabled
+- `foo/destpage.LL.html` if `usedirs` is disabled
+### Link to negotiated language
-Templates
----------
+If `po_link_to` is set to `negotiated`, `\[[page]]` links to the
+negotiated preferred language, *i.e.* `foo/page/`.
-The `OTHERLANGUAGES` loop provides ways to display the existing
-translations and/or master page. One typically adds the following code
-to `templates/page.tmpl`:
+(In)compatibility notes:
-
-
-
+- if `usedirs` is disabled, it does not make sense to set `po_link_to`
+ to `negotiated`; this option combination is neither implemented
+ nor allowed.
+- if the web server does not support Content Negotiation, setting
+ `po_link_to` to `negotiated` will produce a unusable website.
Server support
@@ -122,17 +103,16 @@ Server support
Apache
------
-Using `mod_negotiation` makes it really easy to have Apache serve the
-page in the client's preferred language, if available. This is the
-default Debian Apache configuration.
+Using Apache `mod_negotiation` makes it really easy to have Apache
+serve any page in the client's preferred language, if available.
+This is the default Debian Apache configuration.
When `usedirs` is enabled, one has to set `DirectoryIndex index` for
the wiki context.
Setting `DefaultLanguage LL` (replace `LL` with your default MIME
-language) for the wiki context can be needed, to ensure
+language code) for the wiki context can help to ensure
`bla/page/index.en.html` is served as `Content-Language: LL`.
-**FIXME**: is it still needed with the new `.en.html` naming convention?
lighttpd
--------
@@ -143,117 +123,206 @@ lighttpd unfortunately does not support content negotiation.
emulate this?
-TODO
-====
+Usage
+=====
-Link relationships
-------------------
+Templates
+---------
-Should pages using the `OTHERLANGUAGES` template loop be declared as
-linking to the same page in other versions?
+The `ISTRANSLATION` and `ISTRANSLATABLE` variables can be used to
+display things only on translatable or translation pages.
-View translation status
------------------------
+### Display page's versions in other languages
-One should be able to view some information about the translation
-completeness, either for a given page or for the whole wiki.
+The `OTHERLANGUAGES` loop provides ways to display other languages'
+versions of the same page, and the translations' status.
-This should not be too hard using gettext tools. If this is
-implemented as a
-[HTML::Template](http://search.cpan.org/search?mode=dist&query=HTML%3A%3ATemplate)
-loop, a page using it should depend on any "master" and "slave" pages
-whose status is being displayed.
+One typically adds the following code to `templates/page.tmpl`:
-If it's not too heavy to compute, this status data may be made
-available in the `OTHERLANGUAGES` template loop; else, a dedicated
-loop would be needed.
+
+
+
+
+ -
+ ">
+
+ ( %)
+
+
+
+
+
+
+
+
-**FIXME** `refreshpofiles` uses `system()`, whose args have to be
-checked more thoroughly to prevent any security issue (command
-injection, etc.).
+Additional PageSpec tests
+-------------------------
-UI consistency: rename "Edit" button on slave pages
----------------------------------------------------
+This plugin enhances the regular [[ikiwiki/PageSpec]] syntax with some
+additional tests that are documented [[here|ikiwiki/pagespec/po]].
-It may be surprising to some, after having pressed *Edit* on a wiki
-page, to end up editing a strange looking PO file. The *Edit* button
-displayed on "slave" pages must therefore be renamed *Improve
-translation* .
+Automatic PO file update
+------------------------
-Pages selection depending on language
--------------------------------------
+Committing changes to a "master" page:
-To improve user navigation in a multi-lingual wiki, site developers
-must be enabled to write:
+1. updates the POT file and the PO files for the "slave" languages;
+ the updated PO files are then put under version control;
+2. triggers a refresh of the corresponding HTML slave pages.
- \[[!map pages="dev/* and lang(LL)" feeds="no"]]
+Also, when the plugin has just been enabled, or when a page has just
+been declared as being translatable, the needed POT and PO files are
+created, and the PO files are checked into version control.
- \[[!map pages="dev/* and currentlang()" feeds="no"]]
+Discussion pages
+----------------
-Translation quality assurance
------------------------------
+Discussion should happen in the language in which the pages are
+written for real, *i.e.* the "master" one. If discussion pages are
+enabled, "slave" pages therefore link to the "master" page's
+discussion page.
-Modifying a PO file via the CGI must only be allowed if the new
-version is a valid PO file. As a bonus, check that it provides a more
-complete translation than the existing one.
+Translating
+-----------
-A new `cansave` type of hook would be needed to implement this.
+One can edit the PO files using ikiwiki's CGI (a message-by-message
+interface could also be implemented at some point).
-Note: committing to the underlying repository is a way to bypass
-this check.
+If [[tips/untrusted_git_push]] is setup, one can edit the PO files in one's
+preferred `$EDITOR`, without needing to be online.
-Translating online
-------------------
+TODO
+====
-As PO is a wiki page type, we already have an online PO editor, that
-is ikiwiki's CGI.
+Security checks
+---------------
+
+### Security history
+
+The only past security issues I could find in GNU gettext and po4a
+are:
+
+- [CVE-2004-0966](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0966),
+ *i.e.* [Debian bug #278283](http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=278283):
+ the autopoint and gettextize scripts in the GNU gettext package
+ 1.14 and later versions, as used in Trustix Secure Linux 1.5
+ through 2.1 and other operating systems, allows local users to
+ overwrite files via a symlink attack on temporary files.
+- [CVE-2007-4462](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-4462):
+ `lib/Locale/Po4a/Po.pm` in po4a before 0.32 allows local users to
+ overwrite arbitrary files via a symlink attack on the
+ gettextization.failed.po temporary file.
+
+**FIXME**: check whether this plugin would have been a possible attack
+vector to exploit these vulnerabilities.
+
+Depending on my mood, the lack of found security issues can either
+indicate that there are none, or reveal that no-one ever bothered to
+find (and publish) them.
+
+### PO file features
+
+Can any sort of directives be put in po files that will cause mischief
+(ie, include other files, run commands, crash gettext, whatever)?
+
+> No [documented](http://www.gnu.org/software/gettext/manual/gettext.html#PO-Files)
+> directive is supposed to do so.
+
+### Running po4a on untrusted content
+
+Are there any security issues on running po4a on untrusted content?
+
+> To say the least, this issue is not well covered, at least publicly:
+>
+> - the documentation does not talk about it;
+> - grep'ing the source code for `security` or `trust` gives no answer.
+>
+> I'll ask their opinion to the po4a maintainers.
+>
+> I'm not in a position to audit the code, but I had a look anyway:
+>
+> - no use of `system()`, `exec()` or backticks in `Locale::Po4a`; are
+> there any other way to run external programs in Perl?
+> - a symlink attack vulnerability was already discovered, so I "hope"
+> the code has been checked to find some more already
+> - the po4a parts we are using themselves use the following Perl
+> modules: `DynaLoader`, `Encode`, `Encode::Guess`,
+> `Text::WrapI18N`, `Locale::gettext` (`bindtextdomain`,
+> `textdomain`, `gettext`, `dgettext`)
+>
+> --[[intrigeri]]
+
+### Fuzzing input
+
+I was not able to find any public information about gettext or po4a
+having been tested with a fuzzing program, such as `zzuf` or `fusil`.
+Moreover, some gettext parsers seem to be quite
+[easy to crash](http://fusil.hachoir.org/trac/browser/trunk/fuzzers/fusil-gettext),
+so it might be useful to bang gettext/po4a's heads against such
+a program in order to easily detect some of the most obvious DoS.
+[[--intrigeri]]
+
+gettext/po4a rough corners
+--------------------------
+
+- fix infinite loop when synchronizing two ikiwiki (when checkouts
+ live in different directories): say bla.fr.po has been updated in
+ repo2; pulling repo2 from repo1 seems to trigger a PO update, that
+ changes bla.fr.po in repo1; then pushing repo1 to repo2 triggers
+ a PO update, that changes bla.fr.po in repo2; etc.; quickly fixed in
+ `629968fc89bced6727981c0a1138072631751fee`, by disabling references
+ in Pot files. Using `Locale::Po4a::write_if_needed` might be
+ a cleaner solution.
+- new translations created in the web interface must get proper
+ charset/encoding gettext metadata, else the next automatic PO update
+ removes any non-ascii chars; possible solution: put such metadata
+ into the Pot file, and let it propagate; should be fixed in
+ `773de05a7a1ee68d2bed173367cf5e716884945a`, time will tell.
+
+Misc. improvements
+------------------
-A message-by-message interface could also be implemented at some
-point; a nice way to do offline translation work (without VCS access)
-still has to be offered, though.
+### page titles
-Translating offline without VCS access
---------------------------------------
+Use nice page titles from meta plugin in links, as inline already
+does. This is actually a duplicate for
+[[bugs/pagetitle_function_does_not_respect_meta_titles]], which might
+be fixed by something like [[todo/using_meta_titles_for_parentlinks]].
-The following workflow should be made possible for translators without
-VCS access who need to edit the PO files in another editor than a web
-browser:
+### source files format
-- download the page's PO file
-- use any PO editor to update the translation
-- upload the updated PO file
+Markdown is supported, great, but what about others? The set of file
+formats supported both in ikiwiki and po4a probably is greater than
+`{markdown}`.
-Implementation note: a generic mechanism to upload a page's source is
-needed: it's only an alternative way to allow saving a the modified
-page's source with the CGI.
+Translation quality assurance
+-----------------------------
-### Short-term workflow
+Modifying a PO file via the CGI must be forbidden if the new version
+is not a valid PO file. As a bonus, check that it provides a more
+complete translation than the existing one.
-A possible workaround is:
+A new `cansave` type of hook would be needed to implement this.
-- pretend to edit the PO file online
-- copy the PO file content from the textarea
-- cancel the edit
-- paste the content into a local file.
-- edit the local file in any PO editor
-- pretend to edit the PO file online
-- paste the modified local file's content into the edit textarea
-- save
+Note: committing to the underlying repository is a way to bypass
+this check.