Re: [PATCH bpf-next 4/9] libbpf: add libbpf_swap_print to get previous print func
From: Stanislav Fomichev <sdf@fomichev.me>
Date: 2019-07-26 21:28:20
Also in:
bpf
On 07/26, Andrii Nakryiko wrote:
libbpf_swap_print allows to restore previously set print function. This is useful when running many independent test with one default print function, but overriding log verbosity for particular subset of tests.
Can we change the return type of libbpf_set_print instead and return the old function from it? Will it break ABI?
quoted hunk ↗ jump to hunk
Signed-off-by: Andrii Nakryiko <redacted> --- tools/lib/bpf/libbpf.c | 8 ++++++++ tools/lib/bpf/libbpf.h | 1 + tools/lib/bpf/libbpf.map | 5 +++++ 3 files changed, 14 insertions(+)diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 8741c39adb1c..0c254b6c9685 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c@@ -79,6 +79,14 @@ void libbpf_set_print(libbpf_print_fn_t fn) __libbpf_pr = fn; } +libbpf_print_fn_t libbpf_swap_print(libbpf_print_fn_t fn) +{ + libbpf_print_fn_t old_print_fn = __libbpf_pr; + + __libbpf_pr = fn; + return old_print_fn; +} + __printf(2, 3) void libbpf_print(enum libbpf_print_level level, const char *format, ...) {diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 5cbf459ece0b..4e0aa893571f 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h@@ -58,6 +58,7 @@ typedef int (*libbpf_print_fn_t)(enum libbpf_print_level level, const char *, va_list ap); LIBBPF_API void libbpf_set_print(libbpf_print_fn_t fn); +LIBBPF_API libbpf_print_fn_t libbpf_swap_print(libbpf_print_fn_t fn); /* Hide internal to user */ struct bpf_object;diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index f9d316e873d8..e211c38ddc43 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map@@ -184,3 +184,8 @@ LIBBPF_0.0.4 { perf_buffer__new_raw; perf_buffer__poll; } LIBBPF_0.0.3; + +LIBBPF_0.0.5 { + global: + libbpf_swap_print; +} LIBBPF_0.0.4;-- 2.17.1