libbpf: return previous print callback from libbpf_set_print

By returning previously set print callback from libbpf_set_print, it's
possible to restore it, eventually. This is useful when running many
independent test with one default print function, but overriding log
verbosity for particular subset of tests.

Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Andrii Nakryiko 2019-07-27 20:25:26 -07:00 committed by Alexei Starovoitov
parent 8160bae21f
commit e87fd8bae4
2 changed files with 5 additions and 2 deletions

View File

@ -74,9 +74,12 @@ static int __base_pr(enum libbpf_print_level level, const char *format,
static libbpf_print_fn_t __libbpf_pr = __base_pr;
void libbpf_set_print(libbpf_print_fn_t fn)
libbpf_print_fn_t libbpf_set_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)

View File

@ -57,7 +57,7 @@ enum libbpf_print_level {
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_set_print(libbpf_print_fn_t fn);
/* Hide internal to user */
struct bpf_object;