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authorAndrii Nakryiko <andrii@kernel.org>2024-01-27 01:09:44 +0300
committerSasha Levin <sashal@kernel.org>2024-03-27 01:16:34 +0300
commitb7b7895399383efdad13dfbe251996a542c6a30f (patch)
tree6e0840b8a0929b3a01ca59f9cceb090090142ebd /tools/lib
parentf24ae2f6aebb507fe4a29a0379fd773b94283116 (diff)
downloadlinux-b7b7895399383efdad13dfbe251996a542c6a30f.tar.xz
libbpf: Fix faccessat() usage on Android
[ 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-release/libc/bionic/faccessat.cpp#50 [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250 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>
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf_internal.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 27e4e320e1a6..878a0d0b51f5 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -18,6 +18,20 @@
#include <libelf.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-release/libc/bionic/faccessat.cpp#50
+ * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
+ */
+#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