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: Andrii Nakryiko <andrii@xxxxxxxxxx> --- tools/lib/bpf/libbpf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index f7364ea82ac1..917d975bd4c6 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -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) -- 2.30.2
