Commit d7c5802f authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

libbpf: preserve errno across pr_warn/pr_info/pr_debug 

As suggested in [0], make sure that libbpf_print saves and restored
errno and as such guaranteed that no matter what actual print callback
user installs, macros like pr_warn/pr_info/pr_debug are completely
transparent as far as errno goes.

While libbpf code is pretty careful about not clobbering important errno
values accidentally with pr_warn(), it's a trivial change to make sure
that pr_warn can be used anywhere without a risk of clobbering errno.

No functional changes, just future proofing.

  [0] https://github.com/libbpf/libbpf/pull/536



Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarDaniel Müller <deso@posteo.net>
Link: https://lore.kernel.org/r/20220810183425.1998735-1-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 43caeec9

tools/lib/bpf/libbpf.c

+5 −0
Original line number Diff line number Diff line
@@ -223,13 +223,18 @@ __printf(2, 3) 
void libbpf_print(enum libbpf_print_level level, const char *format, ...)

{

	va_list args;

	int old_errno;



	if (!__libbpf_pr)

		return;



	old_errno = errno;



	va_start(args, format);

	__libbpf_pr(level, format, args);

	va_end(args);



	errno = old_errno;

}



static void pr_perm_msg(int err)