[PATCH net-next] bpf: install libbpf headers on 'make install'

Install the bpf.h header to $(prefix)/include/bpf/ directory.
This is necessary to build standalone applications using libbpf,
without the need to clone the kernel sources and point to them.

Signed-off-by: Jakub Kicinski <redacted>
---
I'm not 100% sure if it's OK to export the header file and which
directory it should end up in (bpf/? libbpf/?).

 tools/lib/bpf/Makefile | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 1f5300e56b44..22dad416e0bd 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile

@@ -46,6 +46,7 @@ else
 endif
 
 prefix ?= /usr/local
+headerdir = $(prefix)/include/bpf/
 libdir = $(prefix)/$(libdir_relative)
 man_dir = $(prefix)/share/man
 man_dir_SQ = '$(subst ','\'',$(man_dir))'

@@ -90,11 +91,13 @@ endif
 export prefix libdir src obj
 
 # Shell quotes
+headerdir_SQ = $(subst ','\'',$(headerdir))
 libdir_SQ = $(subst ','\'',$(libdir))
 libdir_relative_SQ = $(subst ','\'',$(libdir_relative))
 plugin_dir_SQ = $(subst ','\'',$(plugin_dir))
 
 LIB_FILE = libbpf.a libbpf.so
+HEADER_FILE = bpf.h
 
 VERSION		= $(BPF_VERSION)
 PATCHLEVEL	= $(BPF_PATCHLEVEL)

@@ -189,7 +192,11 @@ install_lib: all_cmd
 	$(call QUIET_INSTALL, $(LIB_FILE)) \
 		$(call do_install,$(LIB_FILE),$(libdir_SQ))
 
-install: install_lib
+install_hdr: all_cmd
+	$(call QUIET_INSTALL, $(HEADER_FILE)) \
+		$(call do_install,$(HEADER_FILE),$(headerdir_SQ))
+
+install: install_lib install_hdr
 
 ### Cleaning rules
 

-- 
2.11.0

On 07/24/2017 11:22 PM, Jakub Kicinski wrote:

Install the bpf.h header to $(prefix)/include/bpf/ directory.
This is necessary to build standalone applications using libbpf,
without the need to clone the kernel sources and point to them.

Signed-off-by: Jakub Kicinski <redacted>
---
I'm not 100% sure if it's OK to export the header file and which
directory it should end up in (bpf/? libbpf/?).

Given the Makefile is heavily derived from tools/lib/traceevent/,
we should probably have a similar install_headers target instead,
in order to keep semantics similar. /include/bpf/ should be good.

Add a new target to install the bpf.h header to $(prefix)/include/bpf/ 
directory.  This is necessary to build standalone applications using 
libbpf, without the need to clone the kernel sources and point to them.

Signed-off-by: Jakub Kicinski <redacted>
---
v2:
 - make the header installation similar to tools/lib/traceevent (Daniel).

The functional change is that the header will not be installed as part
of make install, one has to make install_headers, which seems OK.

Out of curiosity - why are only "force elfdep bpfdep" added to the PHONY
target?  Is there some Makefile magic that makes adding install* targets
there unnecessary?  Or does the PHONY target just not matter in practice
so it's not updated?

 tools/lib/bpf/Makefile | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile
index 1f5300e56b44..445289555487 100644
--- a/tools/lib/bpf/Makefile
+++ b/tools/lib/bpf/Makefile

@@ -189,6 +189,10 @@ install_lib: all_cmd
 	$(call QUIET_INSTALL, $(LIB_FILE)) \
 		$(call do_install,$(LIB_FILE),$(libdir_SQ))
 
+install_headers:
+	$(call QUIET_INSTALL, headers) \
+		$(call do_install,bpf.h,$(prefix)/include/bpf,644)
+
 install: install_lib
 
 ### Cleaning rules

-- 
2.11.0

On 07/25/2017 08:17 PM, Jakub Kicinski wrote:

Add a new target to install the bpf.h header to $(prefix)/include/bpf/
directory.  This is necessary to build standalone applications using
libbpf, without the need to clone the kernel sources and point to them.

Signed-off-by: Jakub Kicinski <redacted>

Looks good to me, we might do the same for libbpf.h later on as
well, though the naming scheme is a confusing choice (bpf.h and
libbpf.h).

Acked-by: Daniel Borkmann <daniel@iogearbox.net>

---
v2:
  - make the header installation similar to tools/lib/traceevent (Daniel).

The functional change is that the header will not be installed as part
of make install, one has to make install_headers, which seems OK.

Out of curiosity - why are only "force elfdep bpfdep" added to the PHONY
target?  Is there some Makefile magic that makes adding install* targets
there unnecessary?  Or does the PHONY target just not matter in practice
so it's not updated?

Arnaldo might know better.

From: Jakub Kicinski <redacted>
Date: Tue, 25 Jul 2017 11:17:11 -0700

Add a new target to install the bpf.h header to $(prefix)/include/bpf/ 
directory.  This is necessary to build standalone applications using 
libbpf, without the need to clone the kernel sources and point to them.

Signed-off-by: Jakub Kicinski <redacted>

Applied, thank you.