Re: [PATCH bpf] libbpf: Move BPF_SEQ_PRINTF and BPF_SNPRINTF to bpf_helpers.h
From: Andrii Nakryiko
Date: Tue May 25 2021 - 15:51:57 EST
On Tue, May 25, 2021 at 4:38 AM Florent Revest <revest@xxxxxxxxxxxx> wrote:
>
> These macros are convenient wrappers around the bpf_seq_printf and
> bpf_snprintf helpers. They are currently provided by bpf_tracing.h which
> targets low level tracing primitives. bpf_helpers.h is a better fit.
>
> The __bpf_narg and __bpf_apply are needed in both files and provided
> twice.
>
> Reported-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
> ---
> kernel/bpf/preload/iterators/iterators.bpf.c | 1 -
> tools/lib/bpf/bpf_helpers.h | 58 +++++++++++++++++++
> tools/lib/bpf/bpf_tracing.h | 52 -----------------
> .../bpf/progs/bpf_iter_bpf_hash_map.c | 1 -
> .../selftests/bpf/progs/bpf_iter_bpf_map.c | 1 -
> .../selftests/bpf/progs/bpf_iter_ipv6_route.c | 1 -
> .../selftests/bpf/progs/bpf_iter_netlink.c | 1 -
> .../selftests/bpf/progs/bpf_iter_task.c | 1 -
> .../selftests/bpf/progs/bpf_iter_task_btf.c | 1 -
> .../selftests/bpf/progs/bpf_iter_task_file.c | 1 -
> .../selftests/bpf/progs/bpf_iter_task_stack.c | 1 -
> .../selftests/bpf/progs/bpf_iter_task_vma.c | 1 -
> .../selftests/bpf/progs/bpf_iter_tcp4.c | 1 -
> .../selftests/bpf/progs/bpf_iter_tcp6.c | 1 -
> .../selftests/bpf/progs/bpf_iter_udp4.c | 1 -
> .../selftests/bpf/progs/bpf_iter_udp6.c | 1 -
> .../selftests/bpf/progs/test_snprintf.c | 1 -
> 17 files changed, 58 insertions(+), 67 deletions(-)
>
> diff --git a/kernel/bpf/preload/iterators/iterators.bpf.c b/kernel/bpf/preload/iterators/iterators.bpf.c
> index 52aa7b38e8b8..03af863314ea 100644
> --- a/kernel/bpf/preload/iterators/iterators.bpf.c
> +++ b/kernel/bpf/preload/iterators/iterators.bpf.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include <linux/bpf.h>
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_core_read.h>
>
> #pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
> diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
> index 9720dc0b4605..eade4f335ad1 100644
> --- a/tools/lib/bpf/bpf_helpers.h
> +++ b/tools/lib/bpf/bpf_helpers.h
> @@ -158,4 +158,62 @@ enum libbpf_tristate {
> #define __kconfig __attribute__((section(".kconfig")))
> #define __ksym __attribute__((section(".ksyms")))
>
> +#define ___bpf_concat(a, b) a ## b
> +#define ___bpf_apply(fn, n) ___bpf_concat(fn, n)
> +#define ___bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, N, ...) N
> +#define ___bpf_narg(...) \
> + ___bpf_nth(_, ##__VA_ARGS__, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
wouldn't this conflict if both bpf_tracing.h and bpf_helpers.h are
included in the same file? We can probably guard this block with
custom #ifdef both in bpf_helpers.h and bpf_tracing.h to avoid
dependency on order of includes?
> +
> +#define ___bpf_fill0(arr, p, x) do {} while (0)
> +#define ___bpf_fill1(arr, p, x) arr[p] = x
> +#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
> +#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
> +#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
> +#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
> +#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
> +#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
> +#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
> +#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
> +#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
> +#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
> +#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
> +#define ___bpf_fill(arr, args...) \
> + ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)
> +
> +/*
> + * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
> + * in a structure.
> + */
> +#define BPF_SEQ_PRINTF(seq, fmt, args...) \
> +({ \
> + static const char ___fmt[] = fmt; \
> + unsigned long long ___param[___bpf_narg(args)]; \
> + \
> + _Pragma("GCC diagnostic push") \
> + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
> + ___bpf_fill(___param, args); \
> + _Pragma("GCC diagnostic pop") \
> + \
> + bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
> + ___param, sizeof(___param)); \
> +})
> +
> +/*
> + * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
> + * an array of u64.
> + */
> +#define BPF_SNPRINTF(out, out_size, fmt, args...) \
> +({ \
> + static const char ___fmt[] = fmt; \
> + unsigned long long ___param[___bpf_narg(args)]; \
> + \
> + _Pragma("GCC diagnostic push") \
> + _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
> + ___bpf_fill(___param, args); \
> + _Pragma("GCC diagnostic pop") \
> + \
> + bpf_snprintf(out, out_size, ___fmt, \
> + ___param, sizeof(___param)); \
> +})
> +
> #endif
> diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
> index 8c954ebc0c7c..2189f6bf6d2d 100644
> --- a/tools/lib/bpf/bpf_tracing.h
> +++ b/tools/lib/bpf/bpf_tracing.h
> @@ -413,56 +413,4 @@ typeof(name(0)) name(struct pt_regs *ctx) \
> } \
> static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)
>
> -#define ___bpf_fill0(arr, p, x) do {} while (0)
> -#define ___bpf_fill1(arr, p, x) arr[p] = x
> -#define ___bpf_fill2(arr, p, x, args...) arr[p] = x; ___bpf_fill1(arr, p + 1, args)
> -#define ___bpf_fill3(arr, p, x, args...) arr[p] = x; ___bpf_fill2(arr, p + 1, args)
> -#define ___bpf_fill4(arr, p, x, args...) arr[p] = x; ___bpf_fill3(arr, p + 1, args)
> -#define ___bpf_fill5(arr, p, x, args...) arr[p] = x; ___bpf_fill4(arr, p + 1, args)
> -#define ___bpf_fill6(arr, p, x, args...) arr[p] = x; ___bpf_fill5(arr, p + 1, args)
> -#define ___bpf_fill7(arr, p, x, args...) arr[p] = x; ___bpf_fill6(arr, p + 1, args)
> -#define ___bpf_fill8(arr, p, x, args...) arr[p] = x; ___bpf_fill7(arr, p + 1, args)
> -#define ___bpf_fill9(arr, p, x, args...) arr[p] = x; ___bpf_fill8(arr, p + 1, args)
> -#define ___bpf_fill10(arr, p, x, args...) arr[p] = x; ___bpf_fill9(arr, p + 1, args)
> -#define ___bpf_fill11(arr, p, x, args...) arr[p] = x; ___bpf_fill10(arr, p + 1, args)
> -#define ___bpf_fill12(arr, p, x, args...) arr[p] = x; ___bpf_fill11(arr, p + 1, args)
> -#define ___bpf_fill(arr, args...) \
> - ___bpf_apply(___bpf_fill, ___bpf_narg(args))(arr, 0, args)
> -
> -/*
> - * BPF_SEQ_PRINTF to wrap bpf_seq_printf to-be-printed values
> - * in a structure.
> - */
> -#define BPF_SEQ_PRINTF(seq, fmt, args...) \
> -({ \
> - static const char ___fmt[] = fmt; \
> - unsigned long long ___param[___bpf_narg(args)]; \
> - \
> - _Pragma("GCC diagnostic push") \
> - _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
> - ___bpf_fill(___param, args); \
> - _Pragma("GCC diagnostic pop") \
> - \
> - bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
> - ___param, sizeof(___param)); \
> -})
> -
> -/*
> - * BPF_SNPRINTF wraps the bpf_snprintf helper with variadic arguments instead of
> - * an array of u64.
> - */
> -#define BPF_SNPRINTF(out, out_size, fmt, args...) \
> -({ \
> - static const char ___fmt[] = fmt; \
> - unsigned long long ___param[___bpf_narg(args)]; \
> - \
> - _Pragma("GCC diagnostic push") \
> - _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
> - ___bpf_fill(___param, args); \
> - _Pragma("GCC diagnostic pop") \
> - \
> - bpf_snprintf(out, out_size, ___fmt, \
> - ___param, sizeof(___param)); \
> -})
> -
> #endif
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
> index 6dfce3fd68bc..0aa3cd34cbe3 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_hash_map.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_map.c b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_map.c
> index b83b5d2e17dc..6c39e86b666f 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_bpf_map.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_bpf_map.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_ipv6_route.c b/tools/testing/selftests/bpf/progs/bpf_iter_ipv6_route.c
> index d58d9f1642b5..784a610ce039 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_ipv6_route.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_ipv6_route.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> index 95989f4c99b5..a28e51e2dcee 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_netlink.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task.c b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
> index b7f32c160f4e..c86b93f33b32 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_task.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c
> index a1ddc36f13ec..bca8b889cb10 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_btf.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020, Oracle and/or its affiliates. */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_core_read.h>
>
> #include <errno.h>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_file.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_file.c
> index b2f7c7c5f952..6e7b400888fe 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_task_file.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_file.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c
> index 43c36f5f7649..f2b8167b72a8 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_stack.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c b/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c
> index 11d1aa37cf11..4ea6a37d1345 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c
> @@ -2,7 +2,6 @@
> /* Copyright (c) 2020 Facebook */
> #include "bpf_iter.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> char _license[] SEC("license") = "GPL";
>
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> index 54380c5e1069..2e4775c35414 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_endian.h>
>
> char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> index b4fbddfa4e10..943f7bba180e 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_endian.h>
>
> char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> index f258583afbbd..cf0c485b1ed7 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp4.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_endian.h>
>
> char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> index 65f93bb03f0f..5031e21c433f 100644
> --- a/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> +++ b/tools/testing/selftests/bpf/progs/bpf_iter_udp6.c
> @@ -3,7 +3,6 @@
> #include "bpf_iter.h"
> #include "bpf_tracing_net.h"
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
> #include <bpf/bpf_endian.h>
>
> char _license[] SEC("license") = "GPL";
> diff --git a/tools/testing/selftests/bpf/progs/test_snprintf.c b/tools/testing/selftests/bpf/progs/test_snprintf.c
> index e35129bea0a0..e2ad26150f9b 100644
> --- a/tools/testing/selftests/bpf/progs/test_snprintf.c
> +++ b/tools/testing/selftests/bpf/progs/test_snprintf.c
> @@ -3,7 +3,6 @@
>
> #include <linux/bpf.h>
> #include <bpf/bpf_helpers.h>
> -#include <bpf/bpf_tracing.h>
>
> __u32 pid = 0;
>
> --
> 2.31.1.818.g46aad6cb9e-goog
>