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SubjectRe: [PATCH v5 11/15] tools/bpf/bpftool: use TASK_COMM_LEN_16 instead of hard-coded 16
On Wed, Oct 20, 2021 at 8:46 PM Yafang Shao <laoar.shao@gmail.com> wrote:
>
> Use TASK_COMM_LEN_16 instead of hard-coded 16 to make it more grepable.
> It uses bpf_probe_read_kernel() to get task comm, which may return a
> string without nul terminator. We should use bpf_probe_read_kernel_str()
> instead.
>
> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>
> Cc: Kees Cook <keescook@chromium.org>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Petr Mladek <pmladek@suse.com>
> ---
> tools/bpf/bpftool/Makefile | 1 +
> tools/bpf/bpftool/main.h | 3 ++-
> tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 4 ++--
> tools/bpf/bpftool/skeleton/pid_iter.h | 4 +++-
> 4 files changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index d73232be1e99..33fbde84993c 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -164,6 +164,7 @@ $(OUTPUT)%.bpf.o: skeleton/%.bpf.c $(OUTPUT)vmlinux.h $(LIBBPF)
> $(QUIET_CLANG)$(CLANG) \
> -I$(if $(OUTPUT),$(OUTPUT),.) \
> -I$(srctree)/tools/include/uapi/ \
> + -I$(srctree)/tools/include/ \

bpftool shouldn't rely on internal kernel headers for compilation. If
you want to have TASK_COMM_LEN_16 constant for grep-ability, just
#define it where appropriate

> -I$(LIBBPF_PATH) \
> -I$(srctree)/tools/lib \
> -g -O2 -Wall -target bpf -c $< -o $@ && $(LLVM_STRIP) -g $@
> diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h
> index 90caa42aac4c..5efa27188f68 100644
> --- a/tools/bpf/bpftool/main.h
> +++ b/tools/bpf/bpftool/main.h
> @@ -12,6 +12,7 @@
> #include <linux/compiler.h>
> #include <linux/kernel.h>
> #include <linux/hashtable.h>
> +#include <linux/sched/task.h>
> #include <tools/libc_compat.h>
>

[...]

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