sample-package: create

README.adoc

@@ -221,6 +221,7 @@ Not all packages have an alias, when they don't, just use the form:
 ./build -- <pkg>-reconfigure
 ....
 
+[[retype]]
 === Don't retype arguments all the time
 
 It gets annoying to retype `-a aarch64` for every single command, or to remember `./build -B` setups.
@@ -2792,15 +2793,7 @@ Buildroot built-in libraries, mostly under Libraries > Other:
 * libtommath
 * qhull
 
-There are not yet enabled, but it should be easy to so:
-
-* enable them in link:br2[] and rebuild
-* create a test program that uses each library under link:kernel_module/user[]
-
-External open source benchmarks. We will try to create Buildroot packages for them, add them to this repo, and potentially upstream:
-
-* http://parsec.cs.princeton.edu/ Mentioned on docs: http://gem5.org/PARSEC_benchmarks
-* http://www.m5sim.org/Splash_benchmarks
+There are not yet enabled, but it should be easy to so, see: <<add-new-buildroot-packages>>
 
 ===== BLAS
 
@@ -3637,13 +3630,15 @@ dmesg
 
 == Buildroot
 
-=== Change Buildroot options
+=== Custom Buildroot options
 
 We provide the following mechanisms:
 
 * `./build -b mybr2.gitignore`: append the file `mybr2.gitignore` to a single build. Must be passed every time you run `./build`. A good template is provided by:
 * `./build -B 'BR2_SOM_OPTION="myval"'`: append a single option to a single build.
 
+You will then likely want to make those more permanent with: <<retype>>
+
 === Find Buildroot options with make menuconfig
 
 `make menuconfig` is a convenient way to find Buildroot configurations:
@@ -3733,6 +3728,27 @@ watch -n1 'ccache -s'
 
 while a build is going on in another terminal and my cooler is humming. Especially when the hit count goes up ;-) The joys of system programming.
 
+=== Add new Buildroot packages
+
+First, see if you can't get away without actually adding a new package, for example:
+
+* if you have a standalone C file with no dependencies besides the C standard library to be compiled with GCC, just add a new file under link:kernel_module/user[] and you are done
+* if you have a dependency on a library, first check if Buildroot doesn't have a package for it already with `ls buildroot/package`. If yes, just enable that package as explained at: <<custom-buildroot-options>>
+
+If none of those methods are flexible enough for you, create a new package as follows:
+
+* use link:sample_package[] as a starting point
+* fork this repository, and modify that package to do what you want
+* read the comments on that package to get an idea of how to start
+* check the main manual for more complicated things: https://buildroot.org/downloads/manual/manual.html
+* don't forget to rebuild with:
++
+....
+./build -- sample_package-reconfigure
+....
++
+if you make any changes to that package after the initial build: <<rebuild>>
+
 === BR2_TARGET_ROOTFS_EXT2_SIZE
 
 When adding new large package to the Buildroot root filesystem, it may fail with the message:

br2

@@ -1,5 +1,6 @@
 # Custom packages
 BR2_PACKAGE_KERNEL_MODULE=y
+BR2_SAMPLE_PACKAGE=y
 
 # Rootfs
 BR2_TARGET_ROOTFS_CPIO=n

build

@@ -112,7 +112,7 @@ if "$configure"; then
   for p in $(find "${root_dir}/buildroot_patches/" -maxdepth 1 -name '*.patch' -print); do
     patch -N -r - -p 1 <"$p" || :
   done
-  make O="$buildroot_out_dir" BR2_EXTERNAL="../kernel_module:../gem5:../parsec-benchmark" "$defconfig"
+  make O="$buildroot_out_dir" BR2_EXTERNAL="../kernel_module:../gem5:../parsec-benchmark:../sample_package" "$defconfig"
   # TODO Can't get rid of these for now.
   # http://stackoverflow.com/questions/44078245/is-it-possible-to-use-config-fragments-with-buildroots-config
   for config_fragment in $config_fragments; do

sample_package/Config.in

@@ -0,0 +1,4 @@
+config BR2_PACKAGE_SAMPLE_PACKAGE
+	bool "sample_package"
+	help
+		Sample Buildroot package.

sample_package/Makefile

@@ -0,0 +1,16 @@
+.PHONY: all clean
+
+CFLAGS_EXTRA ?= -ggdb3 -fopenmp -O0 -std=c99 -Wall -Werror -Wextra
+IN_EXT ?= .c
+LIBS :=
+OUT_EXT ?= .out
+
+OUTS := $(addsuffix $(OUT_EXT), $(basename $(wildcard *$(IN_EXT))))
+
+all: $(OUTS)
+
+%$(OUT_EXT): %$(IN_EXT)
+	$(CC) $(CFLAGS) $(CFLAGS_EXTRA) -o '$@' '$<' $(LIBS)
+
+clean:
+	rm -f *'$(OUT_EXT)'

sample_package/external.desc

@@ -0,0 +1 @@
+name: SAMPLE_PACKAGE

sample_package/external.mk

@@ -0,0 +1,21 @@
+################################################################################
+#
+# sample_package
+#
+################################################################################
+
+SAMPLE_PACKAGE_VERSION = 1.0
+SAMPLE_PACKAGE_SITE = $(BR2_EXTERNAL_SAMPLE_PACKAGE_PATH)
+SAMPLE_PACKAGE_SITE_METHOD = local
+
+define SAMPLE_PACKAGE_BUILD_CMDS
+  # D contains the source code of this package.
+  $(MAKE) -C '$(@D)' CC="$(TARGET_CC)" LD="$(TARGET_LD)"
+endef
+
+define SAMPLE_PACKAGE_INSTALL_TARGET_CMDS
+  # Anything put inside TARGET_DIR will end up on the guest relative to the root directory.
+  $(INSTALL) -D -m 0755 $(@D)/*.out '$(TARGET_DIR)'
+endef
+
+$(eval $(generic-package))

sample_package/sample_package.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) {
+	puts("hello sample_package");
+	return EXIT_SUCCESS;
+}