Commit bb180fb2 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

libbpf: Factor out common logic of testing and closing FD 



Factor out common piece of logic that detects support for a feature based on
successfully created FD. Also take care of closing FD, if it was created.

Signed-off-by: default avatarAndrii Nakryiko <andriin@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200818213356.2629020-4-andriin@fb.com
parent 47b6cb4d

tools/lib/bpf/libbpf.c

+17 −53
Original line number Diff line number Diff line
@@ -3431,6 +3431,13 @@ bpf_object__probe_loading(struct bpf_object *obj) 
	return 0;

}



static int probe_fd(int fd)

{

	if (fd >= 0)

		close(fd);

	return fd >= 0;

}



static int probe_kern_prog_name(void)

{

	struct bpf_load_program_attr attr;
@@ -3449,12 +3456,7 @@ static int probe_kern_prog_name(void) 
	attr.license = "GPL";

	attr.name = "test";

	ret = bpf_load_program_xattr(&attr, NULL, 0);

	if (ret >= 0) {

		close(ret);

		return 1;

	}



	return 0;

	return probe_fd(ret);

}



static int probe_kern_global_data(void)
@@ -3495,12 +3497,7 @@ static int probe_kern_global_data(void) 


	ret = bpf_load_program_xattr(&prg_attr, NULL, 0);

	close(map);

	if (ret >= 0) {

		close(ret);

		return 1;

	}



	return 0;

	return probe_fd(ret);

}



static int probe_kern_btf_func(void)
@@ -3516,16 +3513,9 @@ static int probe_kern_btf_func(void) 
		/* FUNC x */                                    /* [3] */

		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, 0), 2),

	};

	int btf_fd;



	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),

				      strs, sizeof(strs));

	if (btf_fd >= 0) {

		close(btf_fd);

		return 1;

	}



	return 0;

	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),

					     strs, sizeof(strs)));

}



static int probe_kern_btf_func_global(void)
@@ -3541,16 +3531,9 @@ static int probe_kern_btf_func_global(void) 
		/* FUNC x BTF_FUNC_GLOBAL */                    /* [3] */

		BTF_TYPE_ENC(5, BTF_INFO_ENC(BTF_KIND_FUNC, 0, BTF_FUNC_GLOBAL), 2),

	};

	int btf_fd;



	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),

				      strs, sizeof(strs));

	if (btf_fd >= 0) {

		close(btf_fd);

		return 1;

	}



	return 0;

	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),

					     strs, sizeof(strs)));

}



static int probe_kern_btf_datasec(void)
@@ -3567,16 +3550,9 @@ static int probe_kern_btf_datasec(void) 
		BTF_TYPE_ENC(3, BTF_INFO_ENC(BTF_KIND_DATASEC, 0, 1), 4),

		BTF_VAR_SECINFO_ENC(2, 0, 4),

	};

	int btf_fd;



	btf_fd = libbpf__load_raw_btf((char *)types, sizeof(types),

				      strs, sizeof(strs));

	if (btf_fd >= 0) {

		close(btf_fd);

		return 1;

	}



	return 0;

	return probe_fd(libbpf__load_raw_btf((char *)types, sizeof(types),

					     strs, sizeof(strs)));

}



static int probe_kern_array_mmap(void)
@@ -3588,14 +3564,8 @@ static int probe_kern_array_mmap(void) 
		.value_size = sizeof(int),

		.max_entries = 1,

	};

	int fd;



	fd = bpf_create_map_xattr(&attr);

	if (fd >= 0) {

		close(fd);

		return 1;

	}

	return 0;

	return probe_fd(bpf_create_map_xattr(&attr));

}



static int probe_kern_exp_attach_type(void)
@@ -3605,7 +3575,6 @@ static int probe_kern_exp_attach_type(void) 
		BPF_MOV64_IMM(BPF_REG_0, 0),

		BPF_EXIT_INSN(),

	};

	int fd;



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

	/* use any valid combination of program type and (optional)
@@ -3619,12 +3588,7 @@ static int probe_kern_exp_attach_type(void) 
	attr.insns_cnt = ARRAY_SIZE(insns);

	attr.license = "GPL";



	fd = bpf_load_program_xattr(&attr, NULL, 0);

	if (fd >= 0) {

		close(fd);

		return 1;

	}

	return 0;

	return probe_fd(bpf_load_program_xattr(&attr, NULL, 0));

}



enum kern_feature_result {

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