I'm trying to compile the sample bpf program in Linux source code. So I downloaded the current kernel source code and entered samples/bpf
folder
apt source linux
cd linux-*/samples/bpf
Then I tried to compile a sample program with gcc:
# gcc sock_example.c
sock_example.c:29:10: fatal error: bpf/bpf.h: No such file or directory
29 | #include <bpf/bpf.h>
| ^~~~~~~~~~~
compilation terminated.
And I'm unable to find bpf/bpf.h
with apt-file
# apt-file find bpf/bpf.h
(no output)
What was wrong?
CodePudding user response:
You need to install libbpf:
git clone --depth 1 https://github.com/libbpf/libbpf
cd src
sudo make install
CodePudding user response:
The Linux eBPF samples come with a rather long Makefile. It handles a lot of cases and integrates well with the kernel building workflow, but makes it more complicated to build the samples outside of the kernel tree.
For example, this Makefile adds a number of includes directories, such as TPROGS_CFLAGS = -I$(srctree)/tools/lib/
, meaning that bpf/bpf.h
will not be fetched from your OS' libraries but from tools/lib/
under your kernel repository.
Here are a few options that you can consider to compile your program:
- Adjust the existing Makefile to use it to build your own programs, for example by adding your kernel code to the
tprogs-y
target. - Install libbpf from the kernel repo (
sudo make -C tools/lib/bpf install
) or from its GitHub mirror. This should install the headers, and gcc should then be able to find them. - Adjust your compile option to tell gcc where to look for the header (
gcc -I <path/to/linux>/tools/lib
). - (Adjust the include path in
#include <bpf/bpf.h>
to make it point to your library.)