bpf: libbpf: retry map creation without the name (23499442) · Commits · 戴 / test

Since commit ("bpf: libbpf: Provide basic API support to specify BPF obj name"), libbpf unconditionally sets bpf_attr->name for maps. Pre v4.14 kernels don't know about map names and return an error about unexpected non-zero data. Retry sys_bpf without a map name to cover older kernels. v2 changes: * check for errno == EINVAL as suggested by Daniel Borkmann Signed-off-by:

Stanislav Fomichev <sdf@google.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net>

tools/lib/bpf/bpf.c

+10 −1

Original line number	Diff line number	Diff line
		@@ -69,6 +69,7 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
		{
		__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
		union bpf_attr attr;
		int ret;

		memset(&attr, '\0', sizeof(attr));

		@@ -86,8 +87,16 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
		attr.map_ifindex = create_attr->map_ifindex;
		attr.inner_map_fd = create_attr->inner_map_fd;

		ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
		if (ret < 0 && errno == EINVAL && create_attr->name) {
		/* Retry the same syscall, but without the name.
		* Pre v4.14 kernels don't support map names.
		*/
		memset(attr.map_name, 0, sizeof(attr.map_name));
		return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
		}
		return ret;
		}

		int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
		int key_size, int value_size, int max_entries,

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