From: Andrii Nakryiko andrii@kernel.org
[ Upstream commit ad57654053805bf9a62602aaec74cc78edb6f235 ]
Android implementation of libc errors out with -EINVAL in faccessat() if passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by detecting Android and redefining AT_EACCESS to 0, it's equivalent on Android.
[0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-rele... [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-191132425...
Fixes: 6a4ab8869d0b ("libbpf: Fix the case of running as non-root with capabilities") Signed-off-by: Andrii Nakryiko andrii@kernel.org Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Jiri Olsa jolsa@kernel.org Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf_internal.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 377642ff51fce..8669f6e0f6e2f 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -17,6 +17,20 @@ #include <unistd.h> #include "relo_core.h"
+/* Android's libc doesn't support AT_EACCESS in faccessat() implementation + * ([0]), and just returns -EINVAL even if file exists and is accessible. + * See [1] for issues caused by this. + * + * So just redefine it to 0 on Android. + * + * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-rele... + * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-191132425... + */ +#ifdef __ANDROID__ +#undef AT_EACCESS +#define AT_EACCESS 0 +#endif + /* make sure libbpf doesn't use kernel-only integer typedefs */ #pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64