bpf tools: Allow caller to set printing function (b3f59d66) · Commits · 戴 / test

By libbpf_set_print(), users of libbpf are allowed to register he/she own debug, info and warning printing functions. Libbpf will use those functions to print messages. If not provided, default info and warning printing functions are fprintf(stderr, ...); default debug printing is NULL. This API is designed to be used by perf, enables it to register its own logging functions to make all logs uniform, instead of separated logging level control. Signed-off-by:

Wang Nan <wangnan0@huawei.com> Acked-by:

Alexei Starovoitov <ast@plumgrid.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@gmail.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kaixu Xia <xiakaixu@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1435716878-189507-5-git-send-email-wangnan0@huawei.com Signed-off-by:

Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/bpf/libbpf.c

+40 −0

Original line number	Diff line number	Diff line
		@@ -7,8 +7,48 @@
		*/

		#include <stdlib.h>
		#include <stdio.h>
		#include <stdarg.h>
		#include <string.h>
		#include <unistd.h>
		#include <asm/unistd.h>
		#include <linux/bpf.h>

		#include "libbpf.h"

		#define __printf(a, b) __attribute__((format(printf, a, b)))

		__printf(1, 2)
		static int __base_pr(const char *format, ...)
		{
		va_list args;
		int err;

		va_start(args, format);
		err = vfprintf(stderr, format, args);
		va_end(args);
		return err;
		}

		static __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
		static __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
		static __printf(1, 2) libbpf_print_fn_t __pr_debug;

		#define __pr(func, fmt, ...) \
		do { \
		if ((func)) \
		(func)("libbpf: " fmt, ##__VA_ARGS__); \
		} while (0)

		#define pr_warning(fmt, ...) __pr(__pr_warning, fmt, ##__VA_ARGS__)
		#define pr_info(fmt, ...) __pr(__pr_info, fmt, ##__VA_ARGS__)
		#define pr_debug(fmt, ...) __pr(__pr_debug, fmt, ##__VA_ARGS__)

		void libbpf_set_print(libbpf_print_fn_t warn,
		libbpf_print_fn_t info,
		libbpf_print_fn_t debug)
		{
		__pr_warning = warn;
		__pr_info = info;
		__pr_debug = debug;
		}

tools/lib/bpf/libbpf.h

+12 −0

Original line number	Diff line number	Diff line
		@@ -8,4 +8,16 @@
		#ifndef __BPF_LIBBPF_H
		#define __BPF_LIBBPF_H

		/*
		* In include/linux/compiler-gcc.h, __printf is defined. However
		* it should be better if libbpf.h doesn't depend on Linux header file.
		* So instead of __printf, here we use gcc attribute directly.
		*/
		typedef int (libbpf_print_fn_t)(const char , ...)
		__attribute__((format(printf, 1, 2)));

		void libbpf_set_print(libbpf_print_fn_t warn,
		libbpf_print_fn_t info,
		libbpf_print_fn_t debug);

		#endif

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