ktap: deterministic build

Add some configuration to the build process of ktap, to get a more deterministic build. Currently, the v0.4 recipe will build with libelf support (from the elfutils recipe), if that is found during the compile stage, thus we have a non-deterministic build going on.

At the same time, I'm also adding support for the FFI configuration. This part has only been imlemented with a limited build test, as it's only supported on x86_64 (which I'm not normally building for).

The configuration of both LIBELF and FFI has been implemented using PACKAGECONFIG, even though it's only the LIBELF part that make any real use of that infrastructure. For FFI, it's only been used to get a consistent configuration tool for both options.

* basic FFI support (depend on CONFIG_KTAP_FFI) FFI will allow call kernel function from ktap script

cdef [[ int printk(char *fmt, ...); ]] C.printk("this is ffi printk from ktap\n")

(currently only support basic C types, structure support is ongoing)

---
Changes v1 -> v2:
* Remove PACKAGECONFIG[ffi] from ktap_v0.4.bb, as it's already defined in ktap.inc.

The following changes since commit 3402bfac6b595c622e4590a8ff5eaaa854e2a2a3:

inetutils: fix compile error when PATH_PROCNET_DEV is undefined (2014-01-08 22:26:26 +0000)

are available in the git repository at:

git://github.com/darander/meta-oe ktap_v0.4
https://github.com/darander/meta-oe/tree/ktap_v0.4

Anders Darander (1):
ktap: add configs for elfutils and ffi

 meta-oe/recipes-kernel/ktap/ktap-module_0.4.bb |  5 ++++-
 meta-oe/recipes-kernel/ktap/ktap.inc           |  2 ++
 meta-oe/recipes-kernel/ktap/ktap_0.4.bb        | 11 ++++++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)

1.8.5.2

libelf (elfutils) is required for resolving symbols in DSO and for sdt (taken from ktap docs). The earlier v0.4 recipe built ktap against libelf if it was found, thus enable it per default.

FFI needs to be enabled for both userspace and kernel module. Currently, it is only supported for x86_64 (enforced when building ktap-module).

---
 meta-oe/recipes-kernel/ktap/ktap-module_0.4.bb |  5 ++++-
 meta-oe/recipes-kernel/ktap/ktap.inc           |  2 ++
 meta-oe/recipes-kernel/ktap/ktap_0.4.bb        | 11 ++++++++++-
 3 files changed, 16 insertions(+), 2 deletions(-)

index 12167ea..ce6885c 100644
@@ -6,8 +6,11 @@ DESCRIPTION = "KTAP is a scripting dynamic tracing tool for Linux"
 
 inherit module
 
+# Available package configs: ffi (only supported on x86_64)
+PACKAGECONFIG ?= ""
+
 # Only build the module
-MAKE_TARGETS = "mod"
+MAKE_TARGETS = "${@base_contains('PACKAGECONFIG', 'ffi', 'FFI=1', '', d)} mod"
 
 # Kernel module packages MUST begin with 'kernel-module-', otherwise
 # multilib image generation can fail.

index 7e60453..93a4e2c 100644
@@ -9,3 +9,5 @@ SRC_URI = "git://github.com/ktap/ktap.git"
 
 S = "${WORKDIR}/git"
 
+# Package config is abused as a general compile time configuration tool.
+PACKAGECONFIG[ffi] = ""

index f5dd62f..20f94d5 100644
@@ -5,8 +5,17 @@ require ktap.inc
 SUMMARY = "KTAP is a scripting dynamic tracing tool for Linux"
 DEPENDS = "ktap-module"
 
+#Available package configs:
+# libelf - needed to resolve symbols in DSO and for sdt
+# ffi    - only supports x86_64 for now!. Needs to be enabled for ktap-module too.
+PACKAGECONFIG ?= "libelf"
+
+PACKAGECONFIG[libelf] = ",,elfutils"
+
 # Only build the userspace app
-EXTRA_OEMAKE = "ktap"
+EXTRA_OEMAKE = "${@base_contains('PACKAGECONFIG', 'libelf', '', 'NO_LIBELF=1', d)} \
+             ${@base_contains('PACKAGECONFIG', 'ffi', 'FFI=1', '', d)} \
+             ktap"
 
 do_install() {
     install -d ${D}${bindir}

1.8.5.2