[kbuild-devel] Dynamically add objects to be built

[Chris Horlick]

Im having an issue getting my build system set up the way id like and im
hoping someone here can point me in a new direction or perhaps offer some
advice.
If i manually add each .o file i want built to the makefile the lkm will
build with no issues, essentially this works:

OBJS = main.o
#OBJS += wm_algo_common.o
#OBJS += wm_algomgr_ops.o
#OBJS += wm_algomgr_static.o
#OBJS += wm_algo_tcp1.o
#OBJS += wm_algo_tcp2.o
#OBJS += wm_algo_udp.o
#OBJS += wm_arp_reg_method.o
#OBJS += wmc_algomgr.o
#OBJS += wmc_core.o
#OBJS += wmc_core_function.o
#OBJS += wmc_debug.o
#OBJS += wmc_linked_list.o
#OBJS += wm_core_info.o
#OBJS += wm_core_ops.o
#OBJS += wmc_packet_common.o
#OBJS += wmc_regmgr.o wm_driver.o
#OBJS += wm_hashtable.o
#OBJS += wm_network_common.o
#OBJS += wm_regmgr_ops.o
#OBJS += wm_regmgr_static.o

Granted these are commented out but they will build a loadable lkm if i
un-comment the obj lines. What i would really like is just to be able to
drop new sources into my build directory and have the makefile pick them up
and build them auto-magically, something like this:

OBJS = $(patsubst %.c,%.o,$(wildcard $(PWD)/*.c))

Now, this should work because the makefile is in the same directory as the
sources/headers so it should pick up the .c files and substitute to the .o
files then i can build with my default target:

default:
@echo $(OBJS)
$(MAKE) -C $(KDIR) M=$(PWD) PWD=$(PWD) V=1 modules

The issue is the echo statement looks fine but when the makefile switches
into the source one of two things happens depending on how i have the OBJS
line setup. If the objs line is setup like it is in second snipped; because
kbuild prefixes the PWD path to the directory where the makefile is stored
twice the build breaks, like this:

make[2]: *** No rule to make target
`/home/chorlick/Code/watermarking/trunk/code/framework/build/linux/lkm//home/chorlick/Code/watermarking/trunk/code/framework/build/linux/lkm/main.o'

You can see the first
/home/chorlick/Code/watermarking/trunk/code/framework/build/linux/lkdm comes
from kbuild's prefix the second is the PWD path picked up from the wildcard
function in the makefile. This being the case i have tried using this line:

OBJS = $(patsubst %.c,%.o,$(wildcard *.c))

The problem here is that make cant find the sources because when that
variable get evaluated its off in the kernel sources build directory and of
course my code isnt located there. So in a nutshell does anyone know a way
to disable kbuild's path prefixing or a way to force kbuild to evaulate PWD
as something slightly different so i can just use the :

OBJS = $(patsubst %.c,%.o,$(wildcard *.c))

line.

If anyone can point me to the kbuild way of doing things, it would be
greatly appreciated. Thanks!

-chorlick
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Re: [kbuild-devel] Dynamically add objects to be built

[Sam Ravnborg]

First - posting to linux-kbuild will liekly get you more attention.
The old list at sourceforge is no longer active.

[From the bottom of your mail]
 If anyone can point me to the kbuild way of doing things, it would be
 greatly appreciated. Thanks!
The kbuild philosofy is that you specify all .o files.
Considering the many many hours invested writing a single .c file,
then the effort it is to add it to the kbuild file is minimal.

On Thu, Apr 29, 2010 at 11:38:30AM -0500, Chris Horlick wrote:
 Im having an issue getting my build system set up the way id like and im
 hoping someone here can point me in a new direction or perhaps offer some
 advice.
 If i manually add each .o file i want built to the makefile the lkm will
 build with no issues, essentially this works:
 
 OBJS = main.o
 #OBJS += wm_algo_common.o
 #OBJS += wm_algomgr_ops.o
 #OBJS += wm_algomgr_static.o
 #OBJS += wm_algo_tcp1.o
 #OBJS += wm_algo_tcp2.o
 #OBJS += wm_algo_udp.o
 #OBJS += wm_arp_reg_method.o
 #OBJS += wmc_algomgr.o
 #OBJS += wmc_core.o
 #OBJS += wmc_core_function.o
 #OBJS += wmc_debug.o
 #OBJS += wmc_linked_list.o
 #OBJS += wm_core_info.o
 #OBJS += wm_core_ops.o
 #OBJS += wmc_packet_common.o
 #OBJS += wmc_regmgr.o wm_driver.o
 #OBJS += wm_hashtable.o
 #OBJS += wm_network_common.o
 #OBJS += wm_regmgr_ops.o
 #OBJS += wm_regmgr_static.o
 
 Granted these are commented out but they will build a loadable lkm if i
 un-comment the obj lines. What i would really like is just to be able to
 drop new sources into my build directory and have the makefile pick them up
 and build them auto-magically, something like this:
 
 OBJS = $(patsubst %.c,%.o,$(wildcard $(PWD)/*.c))

What you fail to realise is that current directory is the root
of the kernel source when you build your module.

Try something like this:

OBJS := $(patsubst %.c, %.o,$(notdir $(wildcard $(src)/*.c)))

$(wildcard $(src)/*.c) will find all .c files in the directory where you module 
reside
$(notdir ...) remove the path component.

Try to look at the resulting OBJS like this:

$(warning OBJS=$(OBJS))

Note - I used := above. I always avoid using = unless strictly required.

Sam

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Re: [kbuild-devel] Dynamically add objects to be built

[Chris Horlick]

Its a weird build system. The whole idea here is that .c files can be simply
dropped into the build directory and be auto built. I think your notdir
thing worked. I tried something similar with pattern substitution using the
PWD dir but of course the context switching thing killed me. Ill ping back
later to the list with a full solution. Thanks Sam.

On Thu, Apr 29, 2010 at 1:06 PM, Sam Ravnborg s...@ravnborg.org wrote:

 First - posting to linux-kbuild will liekly get you more attention.
 The old list at sourceforge is no longer active.

 [From the bottom of your mail]
  If anyone can point me to the kbuild way of doing things, it would be
  greatly appreciated. Thanks!
 The kbuild philosofy is that you specify all .o files.
 Considering the many many hours invested writing a single .c file,
 then the effort it is to add it to the kbuild file is minimal.

 On Thu, Apr 29, 2010 at 11:38:30AM -0500, Chris Horlick wrote:
  Im having an issue getting my build system set up the way id like and im
  hoping someone here can point me in a new direction or perhaps offer some
  advice.
  If i manually add each .o file i want built to the makefile the lkm will
  build with no issues, essentially this works:
 
  OBJS = main.o
  #OBJS += wm_algo_common.o
  #OBJS += wm_algomgr_ops.o
  #OBJS += wm_algomgr_static.o
  #OBJS += wm_algo_tcp1.o
  #OBJS += wm_algo_tcp2.o
  #OBJS += wm_algo_udp.o
  #OBJS += wm_arp_reg_method.o
  #OBJS += wmc_algomgr.o
  #OBJS += wmc_core.o
  #OBJS += wmc_core_function.o
  #OBJS += wmc_debug.o
  #OBJS += wmc_linked_list.o
  #OBJS += wm_core_info.o
  #OBJS += wm_core_ops.o
  #OBJS += wmc_packet_common.o
  #OBJS += wmc_regmgr.o wm_driver.o
  #OBJS += wm_hashtable.o
  #OBJS += wm_network_common.o
  #OBJS += wm_regmgr_ops.o
  #OBJS += wm_regmgr_static.o
 
  Granted these are commented out but they will build a loadable lkm if i
  un-comment the obj lines. What i would really like is just to be able to
  drop new sources into my build directory and have the makefile pick them
 up
  and build them auto-magically, something like this:
 
  OBJS = $(patsubst %.c,%.o,$(wildcard $(PWD)/*.c))

 What you fail to realise is that current directory is the root
 of the kernel source when you build your module.

 Try something like this:

 OBJS := $(patsubst %.c, %.o,$(notdir $(wildcard $(src)/*.c)))

 $(wildcard $(src)/*.c) will find all .c files in the directory where you
 module reside
 $(notdir ...) remove the path component.

 Try to look at the resulting OBJS like this:

 $(warning OBJS=$(OBJS))

 Note - I used := above. I always avoid using = unless strictly
 required.

Sam




-- 
Thanks,
Chris Horlick
Web Engineer
chorl...@gmail.com
256.479.9562
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