wiki:Projects/OpenLDAP

Version 63 (modified by C Rempel, on Jul 2, 2012 at 5:37:08 AM) (diff)

/* Current / Future Directions */

OpenLDAP

Status: Exploratory Light Weight Directory Access Protocol (LDAP) is used to manage distributed directories over a network.

According to Wikipedia: Historically the OpenLDAP server (slapd, the Standalone LDAP Daemon) architecture was split between a frontend which handles network access and protocol processing, and a backend which deals strictly with data storage. The architecture is modular and many different backends are available for interfacing to other technologies, not just traditional databases.

OpenLDAP has been identified by Dr. Sherrill as a "high-priority" for RTEMS. According to Beyond Linux from Scratch The OpenLDAP package provides an open source implementation of the Lightweight Directory Access Protocol,.

In addition to helping me learn valuable porting skills, this project is on of the first steps towards adding needed modern protocols to RTEMS, so that RTEMS can use LDAP. One of the more major first steps towards modernizing the networking protocols in RTEMS is the RTEMS BSD Porting project.

Goal

Concise statement of the overall goal of the project. Refine this initial statement to include: project deliverable (code, docs, testing), required/suggested methodology, standards of quality, possible goal extensions beyond the main objective.

C Rempel's main goal for porting OpenLDAP to RTEMS is to develop a method of porting semi-complex existing open source packages to RTEMS that is efficient, elegant and complete. Efficient meaning the person porting the software can do so in a matter of days or weeks. Elegant meaning the essence of the original source package, and the RTEMS source are preserved: as few lines of code are modified as possible in both the original source package and the RTEMS source as possible, as well as libraries, programs, and executable are installed in the same locations as they would be if they were built in the RTEMS source tree. Completeness meaning not only the libraries are ported, but the programs and tests as well.

Deliverables

Just some ideas from C Rempel:

= RTEMS Webkit Port =

# A Makefile.openldap that builds the SlapD libraries for RTEMS applications # A Makefile that builds the programs. # A program that will run the LDAP testing suite provided by OpenLDAP. Should be automated, as additional tests will be used in the future.== Suggested Methodology ==

Start by porting to RTEMS Addon Packages, then adding a "network-demo style test" using a quick start as a guide.

Standards of Quality

The standards of quality will be a SLAPD server, with a simple webkit demonstration.

Eventually, there should be tests that demonstrate how the SLAPD implementation meets [tools.ietf.org/html/rfc4510 RFC 4510].

Possible Goal Extensions

Explore and (possibly port to RTEMS) the additional packages used by OpenLDAP: # Integrate Database Support # Authentication (such as Cyrus SASL) websitegit # Additional encryption (when configuring openLDAP just type ./configure --help)

Explore and (possibly port to RTEMS) the additional packages that use OpenLDAP: # Apache (did this already, but could be ported more efficiently, elegantly, and completely) # Others

Add an OpenLDAP test to the RTEMS Networking Demos

Requirements

Required Programming Languages

C, Bash, Makefile

Specific Areas of RTEMS or tools

# RTEMS Addon Packages # RTEMS Networking Demos

Level of Familiarity of RTEMS

# Ability to configure RTEMS # Ability to start the Hello, World RTEMS Application from the Examples v2. # Ability to build the AVL library using the RTEMS Addon Packages

Cross-development

# Experience using Makefiles and using configurations for cross development.

Gnu/Linux?

Ability to use the command line, and modify Makefiles. Knowing "grep -r", "find -name", and a text search feature REALLY helpful.

Development / Documentation / Testing Tools

Development Tools: RTEMS Addon Packages, RTEMS Source Tree, RTEMS Toolset, Qemu

Documentation Tools: RTEMS Wiki, comments

Testing Tools: Tests provided by GCC and OpenLDAP, possibly other third party open source LDAP testing software...

Mathematical/algorithmic background

None: this is simply putting two pieces of existing software together.

Other Desirable Skills

# Code reuse skills: can research and use other programmer's code. # Exploration skills: a willingness to peruse the RTEMS git, and other projects, to find code maintained by other developers (to make this port successful after the developer moves on).

Resources

Current RTEMS developers, papers, etc that may help you in this project.

C Rempel is willing to help

Other sections

If you have more to say about the project that doesn't fit in the proposed sections of this template, feel free to add other sections at will.

Acknowledgements

  • who helped add did work

Miscellaneous Sections

A first stab at building Open LDAP

As the project progresses, you will need to add build instructions, etc and this page will evolve from a project description into a HOWTO.

I am building this package because it is simpler than the Apache Runtime, and so is a good way to gain needed experience. I started with using the RTEMS Addon Packages. How to use the RTEMS Addon Packages is outlined http://www.rtems.com/wiki/index.php/RTEMS_Add-On_Packages.

Makefile.openldap

I put the following in rtems-addon-packages/Makefile.openldap

# # Declare supported terminal types. # This value can be augmented/overridden by the site-configuration file #

include ../RTEMS_Makefiles/Makefile.common

# # The following will work only if you have the latest ncurses version # of infocmp installed before trying to build for an RTEMS target. # The cf_cv_type_of_bool hack works around a bug when configuring # for a cross-target. # all:

ac_cv_member_struct_msghdr_msg_control=no \ ac_cv_func_memcmp_working=yes \ ac_cv_func_initgroups=yes \ ac_cv_func_setuid=no \ ./configure \

--host=$(RTEMS_CPU)-rtems4.11 \ --prefix=$(exec_prefix) \ --libdir=$(exec_prefix)/$(RTEMS_BSP)/lib \ --includedir=$(exec_prefix)/$(RTEMS_BSP)/lib/include \ --without-tls \ --with-yielding_select=yes \ --disable-mdb \ --disable-hdb \ --disable-cleartext \ --disable-overlays \ --enable-proctitle \ --enable-debug \ --disable-shared

make make install

Next:

$ cd ~/rtems-addon-packages $ git clone git://git.openldap.org/openldap.git openldap $ cd openldap $ make -f RTEMS_Makefiles/Makefile.openldap

Note: Very insecure! But builds OK.

examples/openldap/BuildTests.sh

I'll probably strip out the Examples section altogether... it was interesting and I learned about RTEMS Makefile.leaf s, but I'm thinking a network-demo is a better testing choice, because the openLDAP tests are written in shell script, and SLAPD may not require a shell to run... To perform a very basic "smoke" test on the build I modified the BuildTest?.sh and Makefile to build the programs needed to run the tests, not the tests themselves. I learned I how to link convenience libraries, and how to use BuildTests?.sh, Makefile.leaf and change leaf.cfg.

Interestingly, I found it necessary to symbolically link the slapd-common header and source to each test, as well as the libutil library.

### examples/openldap/BuildTests.sh ### #!/bin/sh

set -x rm -f rtems-grub.cfg

SRCDIR=../../openldap/tests/progs

Make the common source and header files available to all the test programs

ln -s $SRCDIR/slapd-common.h . ln -s $SRCDIR/slapd-common.c .

Make the lutility convenience library available to all the test programs

ln -s $SRCDIR/../../libraries/liblutil/liblutil.a .

For every test, delete the old link, make a new link, make the test, delete the link and the object file.

for TEST in \

slapd-tester \ slapd-search \ slapd-read \ slapd-addel \ slapd-modrdn \ slapd-modify \ slapd-bind \ slapd-mtread \ ldif-filter

do

rm -f $TEST.c ln -s $SRCDIR/$TEST.c . make TEST=$TEST SRCDIR=$SRCDIR rm -f $TEST.c $TEST.o

done

After making the test programs, remove the links to the common header, source, and lutility library.

rm -f slapd-common.h rm -f slapd-common.c rm -f liblutil.a

(Optional) Next, to make it easier for the end-user, automate building rtems-grub.cfg

# Generate rtems-grub.cfg

Add a comment of what grub is configured to load $(basename $PWD) prints the name of the directory.

echo \# RTEMS Grub configuration for $(basename $PWD) >> rtems-grub.cfg

This part was rather interesting... I've never used a pipe inside of a shell-script call before... list everything in o-optimize, that ends with .exe and count them.

# The number of executables

echo set default = $(ls o-optimize | \ grep '\.'exe | wc -l) >> rtems-grub.cfg

Used the & to use the name of the executable more than once. Note that sed"s/[a-zA-Z\-]/... has to be all on one line

# The menuentries ls o-optimize | \ grep '\.'exe | \ sed "s/[a-zA-Z\-]/menuentry \"RTEMS \-\" \{\n

set root=(hd1,1)\n multiboot (hd1,1)\/o-optimize\/&/" | \

sed "s/\.exe/\.exe\n\}\n/" >> rtems-grub.cfg

# List everything in o-optimize... # that is an executable... # select text composed of letters and format it ... # add a line a right brace, and # another line after any .exe ...

More tips

For integrating legacy libraries/applications to RTEMS... I was playing around with adding the sqlite3 command to the multiio shell, and found the following general ideas very helpful.

# tear and rebuild ALL applications within the kit every time you make a small change. # link the library into EVERY directory with an RTEMS shell application using your new commands.

To tear down and rebuild

rtems-addon-packages$ nano doit.sh

#!/bin/sh make clean make qemu...

To link add an entry to the Makefile:

you can put the library in with the COBJS,

../openldap/.libs/libslapd.a

or link with LD_LIBS

LD_LIBS += -lslapd

or

LD_LIBS += ../openldap/.libs/libslapd.a

examples/openldap/Makefile

I modified the rtems-addon-packages/examples/ncurses/Makefile to turn openldap programs used to test openldap into stand-alone executables.

I had to add slapd-common.c to the C_PIECES, and slapd-common.h to the headers.

Also, to link the liblutil.a convienience library, I had to add liblutil.a to C_O_FILES (it's an object file after-all :), I linked the ldap libraries using LD_LIBS, and increased the HeapSize? by a factor of ten (because it said networking required more -- online research is needed to get an exact size required).

Finally, it's worth noting the $(TEST) parameter is used to identify which test to build, and PGMS stands for programs.

# # $Id$ # # Templates/Makefile?.leaf # Template leaf node Makefile # SRCDIR=../../openldap/tests/progs

# C source names, if any, go here -- minus the .c C_PIECES=slapd-common $(TEST)

C_FILES=$(C_PIECES:%=%.c) C_O_FILES=$(C_PIECES:%=${ARCH}/%.o) liblutil.a

# C++ source names, if any, go here -- minus the .cc CC_PIECES=

CC_FILES=$(CC_PIECES:%=%.cc) CC_O_FILES=$(CC_PIECES:%=${ARCH}/%.o)

H_FILES= slapd-common.h

# Assembly source names, if any, go here -- minus the .s S_PIECES=

S_FILES=$(S_PIECES:%=%.s) S_O_FILES=$(S_FILES:%.s=${ARCH}/%.o)

SRCS=$(C_FILES) $(CC_FILES) $(H_FILES) $(S_FILES) OBJS=$(C_O_FILES) $(CC_O_FILES) $(S_O_FILES)

PGMS=${ARCH}/$(TEST)

# # RTEMS managers go here # MANAGERS=io event message semaphore

include $(RTEMS_MAKEFILE_PATH)/Makefile.inc include $(RTEMS_CUSTOM) include $(PROJECT_ROOT)/make/leaf.cfg

# # (OPTIONAL) Add local stuff here using +=

#

DEFINES +=

CPPFLAGS += -I$(SRCDIR)/../../include CFLAGS +=

LD_PATHS +=

LD_LIBS += -lldap -llber -lldap_r CFLAGS_LD += -Wl,--defsym -Wl,HeapSize?=0x200000 # network needs more space CFLAGS_DEBUG_V +=

# # Add your list of files to delete here. The config files # already know how to delete some stuff, so you may want # to just run 'make clean' first to see what gets missed. # 'make clobber' already includes 'make clean' #

CLEAN_ADDITIONS += CLOBBER_ADDITIONS +=

all: ${ARCH} $(SRCS) $(PGMS)

${ARCH}/$(TEST): ${OBJS} ${LINK_FILES}

$(make-exe)

# Install the program(s), appending _g or _p as appropriate. # for include files, just use $(INSTALL) install: all

$(INSTALL_VARIANT) -m 555 ${PGMS} /usr/local/tftpboot/bootfiles/m68360/

leaf.cfg

To build the executables without errors, I had to change some lines in /opt/rtems-4.11/make/leaf.cfg. nm and size work on object files, with the below changes the build process not only gives fewer errors, but generates .bin and .ralf files in examples/openldap/o-optimize!

define default-bsp-post-link

  • $(NM) -g -n $@ > $(basename $@).num
  • $(SIZE) $@ endef

nm and size work on executables, the RTEMS 4.11 development tree was updated in June 2012 to correctly configure the RTEMS Addon Packages. Thanks!!!

define default-bsp-post-link + $(NM) -g -n $@.exe > $(basename $@).num + $(SIZE) $@.exe endef

Then, I ran BuildTests?.sh

~/rtems-addon-packages/examples/openldap$ ./BuildTests?.sh

Again this only built the programs used to run the tests as stand-alone executables...

SLAPD Test Idea

The OpenLDAP quickstart guide has some interesting ideas.

If the test is written based on step 8 forwards, things that would be required would be: # an appropriate configuration file in the rootfs # a call to slapd with the -d option # adding initial entries to a directory # verify the entry exists

The shell commands required would be

SHLL / slapd -d SHLL / ldapadd -x -D "cn=Manager,dc=ldapdemo,dc=org" -W -f ldapdemo.ldif SHLL / ldapsearch -x -b 'dc=ldapdemo,dc=org' '(objectclass=*)'

Current / Future Directions

# Implement ldap, ldapsearch, and ldapadd in the RTEMS Shell # Write a demo # Try to get an LDAP connection between RTEMS on Qemu and the build machine

I'm exploring implementing ldap, ldapsearch, and ldapadd by taking the multiio application from the RTEMS git, and removing as many commands as possible, then adding back in one command at a time. The RTEMS Shell User's guide is very helpful.

One problem I'm anticipating is the filesystem, but for now, learning to add commands to the shell is turning out to be a challenge.

Hope this helps!

References