Some versions of Android do not implement memfd_create() wrapper in their libc implementation, leading to build failures ([0]). On the other hand, memfd_create() is available as a syscall on quite old kernels (3.17+, while bpf() syscall itself is available since 3.18+), so it is ok to assume that syscall availability and call into it with syscall() helper to avoid Android-specific workarounds. Validated in libbpf-bootstrap's CI ([1]). [0] https://github.com/libbpf/libbpf-bootstrap/actions/runs/7701003207/job/20986080319#step:5:83 [1] https://github.com/libbpf/libbpf-bootstrap/actions/runs/7715988887/job/21031767212?pr=253 Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> --- tools/lib/bpf/libbpf.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index db65ea59a05a..b21fda6b9b85 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1525,11 +1525,20 @@ static Elf64_Sym *find_elf_var_sym(const struct bpf_object *obj, const char *nam return ERR_PTR(-ENOENT); } +/* Some versions of Android don't provide memfd_create() in their libc + * implementation, so avoid complications and just go straight to Linux + * syscall. + */ +static int sys_memfd_create(const char *name, unsigned flags) +{ + return syscall(__NR_memfd_create, name, flags); +} + static int create_placeholder_fd(void) { int fd; - fd = ensure_good_fd(memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC)); + fd = ensure_good_fd(sys_memfd_create("libbpf-placeholder-fd", MFD_CLOEXEC)); if (fd < 0) return -errno; return fd; -- 2.34.1
