Given at cPanel Conference 2017 https://conference.cpanel.net

1. How to speak Perl
cPanel
Todd Rinaldo - cPanel Developer

2. /scripts/upcp
• Honors /etc/cpupdate.conf for if it's enabled
• UPDATES=automatic / manual / never
• Downloads a new version of cPanel
• Does post-update tasks - /scripts/post_sync_cleanup
• does daily /scripts/maintenance tasks

3. /scripts/updatenow
• Updates needed files for version you are switching to
• Uses cpanelsync protocol
• Stage before commit (11.36)
• Installs needed RPMs for version you're switching to
• NEVER call this directly

4. cpanelsync
• Rsync Protocol?
• uses a data file (.cpanelsync) to decide what needs
updating
• Only downloads what is new vs EVERYTHING if cPanel
used RPMs for this.

5. updatenow details
• New version? If not STOP.
• Download the new updatenow.static
• stage all files (compressed) next to where they'll go (cpsrvd-cpanelsync)
• stage all cpanel-* rpms to /ULC/tmp/rpm_downloads
• RPM transaction test?
• ********* DANGER WILL ROBINSON! *********
• Put files in place (mv cpsrvd.cpanelsync cpsrvd)
• Staged to alternate path sometimes.
• Install RPMs

6. /scripts/post_sync_cleanup
• Initialize new files and dbs
• install/*.pm
• Legacy RPM removal
• 1 time scripts
• Restart cpanel

7. Perl Packages
• YAML::Syck
• YAML/Syck.pm
• Acme::LookOfDisapproval
• Acme/LookOfDisapproval.pm

8. @INC
• perl -V
• @INC:
• /usr/local/cpanel/Acme/LookOfDisapproval.pm ?
• /usr/local/cpanel/3rdparty/perl/524/lib64/perl5/
cpanel_lib/x86_64-linux-64int/Acme/
LookOfDisapproval.pm ?
• ...

9. cPanel Name Spaces

10. Cpanel::
• Original name space (/usr/local/cpanel/Cpanel)
• Originally meant as a API for customers to invoke from
cPanel pages.
• Today stores code related to end user interfaces
• Default for misc stuff
• Cpanel/Unix/PID/Tiny.pm

11. Whostmgr::
• /usr/local/cpanel/Whostmgr
• Code specific to WHM interfaces
• xml-api lives here
• May call into the Cpanel:: name space

12. cPanel Perl
• Subroutine calls are explicit if not local
• Imports blocked for memory improvements

14. File Layout
/usr/local/cpanel

15. /ULC/3rdparty
• cpanel-rpms installed here
• PATH=/usr/local/cpanel/3rdparty/bin:$PATH
• jailshell

17. base
https://cpanel.foo.com/cpsess5605988513/

18. paper_lantern
https://cpanel.foo.com/cpsess5605988513/frontend/
paper_lantern/index.html?login=1

19. x3: In Memoriam
Rest in Pieces

20. Misc WHM
• cpaddons/
• Word Press
• /scripts/
• Uncompiled code for utilities

21. src/
• 3rd party software not yet made an RPM
• phpPgAdmin (version conflict heck)
• pam_hulk
• wrap

22. Perl Binaries..
• Elf executables
• Run fast for cgi interface
• 145 binaries shipped right now.
• Compiled Perl binaries

23. Perl Compiler
B::C - https://github.com/cpanelinc/perl-compiler

24. B::C advantages
• Compiles once.
• Run time significantly faster
• Makes CGI a reality

25. Shrink your program
memory size.
• Package removal during C code generation
• COW strings stored as C strings
• duplicates consolidated to 1 string.
• Strings, Arrays, Hashes optimized to perfect size.

26. Example
$> perlcc -o foo foo.pl
$> ./foo
Hello World!

27. cpsrvd
• Handles most cPanel connections (2082..2087)
• cpanel, whm, webserver via this url

28. cpanel
• API for legacy x3 inteface (RIP)
• still used in many paper_lantern (100 left to convert)
• New dev takes place in UAPI

29. UAPI
• The more standard API interface to user level (cpanel)
tasks

30. whostmgr/bin/xml-api
• Used for WHM API calls.
• JSON and XML format (USE JSON)

31. bin/admin/Cpanel/*
• Referred to as adminbins
• Provides limited root functionality to cpanel interfaces

32. whostmgr/bin/whostmgr##
• WHM web interfaces
• Serve all WHM pages
• Do very complicated things, usually as root.

33. Common Code

34. Caveat emptor

35. Cpanel::LoadModule
• Loads code at runtime.
• Used for rarely needed code paths.
• Reduces code size at startup
• Cpanel::LoadModule::load_perl_module('Cpanel::Email::Privs');

36. Cpanel::Config::CpConfGuard
• Interface for /var/cpanel/cpanel.config
• Data validated on save (mostly)
• Most accessors via alternate interface (legacy)
• Cpanel::Config::LoadCpConf::loadcpconf()

37. CpConfGuard Read
• my $hash_ref = Cpanel::Config::LoadCpConf::loadcpconf()
• print "Success" if $hash_ref->{‘mysql-version'}

38. CpConfGuard Write
require Cpanel::Config::CpConfGuard;
my $cpconf_guard = Cpanel::Config::CpConfGuard->new();
$cpconf_guard->{'data'}->{'cpanel_locale'} = $locale;
$cpconf_guard->save();

39. Cpanel::Binaries
• Tracks the location of 3rdparty binaries, often shipped as
cPanel RPMS.
• Reliable across multiple versions of cPanel
$>perl -MCpanel::Binaries -E'say
Cpanel::Binaries::get_binary_location("perl")'
/usr/local/cpanel/3rdparty/perl/524/bin/perl

40. Cpanel::GenSysInfo
• Provides RPM and distro information about the local
system
• Cached for performance - /var/cpanel/sysinfo.config
• Cpanel::GenSysInfo::get_rpm_distro_version() # 7
• C::GSI::get_system_release_file() # /etc/redhat-release
• Cpanel::GenSysInfo::get_rpm_distro() # centos

41. Cpanel::TempFile
• Creates Temp files that are removed when the object
goes out of scope
• Not fork safe
• my $temp_obj = Cpanel::TempFile->new();
• my ( $file_name, $file_handle ) = $temp_obj->file();
• close $file_handle;

42. Smaller, Faster

43. Smaller

44. What we did to shrink
• Unused modules
• Unused code paths
• Regex where index could work.

45. Faster

46. License Validation

47. cPanel Login

48. Disk Usage

49. Hulk White List

50. List Accounts

51. Mail

52. Thank You
toddr@cpanel.net
http://go.cpanel.net/
wednesday