Re: [PATCH bpf-next v3 1/3] libbpf: move pr_*() functions to common header file

[Daniel Borkmann <daniel@iogearbox.net>]

On 01/29/2019 04:12 PM, Magnus Karlsson wrote:
> Move the pr_*() functions in libbpf.c to a common header file called
> libbpf_internal.h. This so that the later libbpf AF_XDP helper library
> code in xsk.c can use these printing functions too.
> 
> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
> ---
>  tools/lib/bpf/libbpf.c          | 30 +-----------------------------
>  tools/lib/bpf/libbpf_internal.h | 41 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 42 insertions(+), 29 deletions(-)
>  create mode 100644 tools/lib/bpf/libbpf_internal.h
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 2ccde17..1d7fe26 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -39,6 +39,7 @@
>  #include <gelf.h>
>  
>  #include "libbpf.h"
> +#include "libbpf_internal.h"
>  #include "bpf.h"
>  #include "btf.h"
>  #include "str_error.h"
> @@ -51,34 +52,6 @@
>  #define BPF_FS_MAGIC		0xcafe4a11
>  #endif
>  
> -#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)
> @@ -96,7 +69,6 @@ void libbpf_set_print(libbpf_print_fn_t warn,
>  		goto out;		\
>  } while(0)
>  
> -
>  /* Copied from tools/perf/util/util.h */
>  #ifndef zfree
>  # define zfree(ptr) ({ free(*ptr); *ptr = NULL; })
> diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
> new file mode 100644
> index 0000000..951c078
> --- /dev/null
> +++ b/tools/lib/bpf/libbpf_internal.h

Just really minor nit: lets name the header utils.h or such. It would also make
sense to move the zfree() and zclose() to this and make use of it.

> @@ -0,0 +1,41 @@
> +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
> +
> +/*
> + * Common internal libbpf functions and definitions.
> + *
> + * Copyright (C) 2013-2015 Alexei Starovoitov <ast@kernel.org>
> + * Copyright (C) 2015 Wang Nan <wangnan0@huawei.com>
> + * Copyright (C) 2015 Huawei Inc.
> + */
> +#ifndef __LIBBPF_LIBBPF_INTERNAL_H
> +#define __LIBBPF_LIBBPF_INTERNAL_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 __maybe_unused __printf(1, 2) libbpf_print_fn_t __pr_warning = __base_pr;
> +static __maybe_unused __printf(1, 2) libbpf_print_fn_t __pr_info = __base_pr;
> +static __maybe_unused __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__)
> +
> +#endif /* __LIBBPF_LIBBPF_INTERNAL_H */
>