From c76e4c228b053eb108e6c3221bef338aa2c98fac Mon Sep 17 00:00:00 2001 From: Taeung Song Date: Mon, 21 Jan 2019 22:06:38 +0900 Subject: [PATCH] libbpf: Show supported ELF section names when failing to guess prog/attach type We need to let users check their wrong ELF section name with proper ELF section names when they fail to get a prog/attach type from it. Because users can't realize libbpf guess prog/attach types from given ELF section names. For example, when a 'cgroup' section name of a BPF program is used, show available ELF section names(types). Before: $ bpftool prog load bpf-prog.o /sys/fs/bpf/prog1 Error: failed to guess program type based on ELF section name cgroup After: libbpf: failed to guess program type based on ELF section name 'cgroup' libbpf: supported section(type) names are: socket kprobe/ kretprobe/ classifier action tracepoint/ raw_tracepoint/ xdp perf_event lwt_in lwt_out lwt_xmit lwt_seg6local cgroup_skb/ingress cgroup_skb/egress cgroup/skb cgroup/sock cgroup/post_bind4 cgroup/post_bind6 cgroup/dev sockops sk_skb/stream_parser sk_skb/stream_verdict sk_skb sk_msg lirc_mode2 flow_dissector cgroup/bind4 cgroup/bind6 cgroup/connect4 cgroup/connect6 cgroup/sendmsg4 cgroup/sendmsg6 Signed-off-by: Taeung Song Cc: Quentin Monnet Cc: Jakub Kicinski Cc: Andrey Ignatov Reviewed-by: Quentin Monnet Acked-by: Jakub Kicinski Signed-off-by: Daniel Borkmann --- tools/bpf/bpftool/prog.c | 10 ++-- tools/lib/bpf/libbpf.c | 46 ++++++++++++++++++- .../selftests/bpf/test_socket_cookie.c | 4 +- 3 files changed, 48 insertions(+), 12 deletions(-) diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 2d1bb7d6ff51..0640e9bc0ada 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -930,10 +930,9 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) err = libbpf_prog_type_by_name(type, &attr.prog_type, &expected_attach_type); free(type); - if (err < 0) { - p_err("unknown program type '%s'", *argv); + if (err < 0) goto err_free_reuse_maps; - } + NEXT_ARG(); } else if (is_prefix(*argv, "map")) { void *new_map_replace; @@ -1028,11 +1027,8 @@ static int load_with_options(int argc, char **argv, bool first_prog_only) err = libbpf_prog_type_by_name(sec_name, &prog_type, &expected_attach_type); - if (err < 0) { - p_err("failed to guess program type based on section name %s\n", - sec_name); + if (err < 0) goto err_close_obj; - } } bpf_program__set_ifindex(pos, ifindex); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 169e347c76f6..2ccde17957e6 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2667,9 +2667,38 @@ static const struct { #undef BPF_EAPROG_SEC #undef BPF_APROG_COMPAT +#define MAX_TYPE_NAME_SIZE 32 + +static char *libbpf_get_type_names(bool attach_type) +{ + int i, len = ARRAY_SIZE(section_names) * MAX_TYPE_NAME_SIZE; + char *buf; + + buf = malloc(len); + if (!buf) + return NULL; + + buf[0] = '\0'; + /* Forge string buf with all available names */ + for (i = 0; i < ARRAY_SIZE(section_names); i++) { + if (attach_type && !section_names[i].is_attachable) + continue; + + if (strlen(buf) + strlen(section_names[i].sec) + 2 > len) { + free(buf); + return NULL; + } + strcat(buf, " "); + strcat(buf, section_names[i].sec); + } + + return buf; +} + int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, enum bpf_attach_type *expected_attach_type) { + char *type_names; int i; if (!name) @@ -2682,12 +2711,20 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type, *expected_attach_type = section_names[i].expected_attach_type; return 0; } + pr_warning("failed to guess program type based on ELF section name '%s'\n", name); + type_names = libbpf_get_type_names(false); + if (type_names != NULL) { + pr_info("supported section(type) names are:%s\n", type_names); + free(type_names); + } + return -EINVAL; } int libbpf_attach_type_by_name(const char *name, enum bpf_attach_type *attach_type) { + char *type_names; int i; if (!name) @@ -2701,6 +2738,13 @@ int libbpf_attach_type_by_name(const char *name, *attach_type = section_names[i].attach_type; return 0; } + pr_warning("failed to guess attach type based on ELF section name '%s'\n", name); + type_names = libbpf_get_type_names(true); + if (type_names != NULL) { + pr_info("attachable section(type) names are:%s\n", type_names); + free(type_names); + } + return -EINVAL; } @@ -2907,8 +2951,6 @@ int bpf_prog_load_xattr(const struct bpf_prog_load_attr *attr, err = bpf_program__identify_section(prog, &prog_type, &expected_attach_type); if (err < 0) { - pr_warning("failed to guess program type based on section name %s\n", - prog->section_name); bpf_object__close(obj); return -EINVAL; } diff --git a/tools/testing/selftests/bpf/test_socket_cookie.c b/tools/testing/selftests/bpf/test_socket_cookie.c index fc7832ee566b..e51d63786ff8 100644 --- a/tools/testing/selftests/bpf/test_socket_cookie.c +++ b/tools/testing/selftests/bpf/test_socket_cookie.c @@ -158,10 +158,8 @@ static int run_test(int cgfd) bpf_object__for_each_program(prog, pobj) { prog_name = bpf_program__title(prog, /*needs_copy*/ false); - if (libbpf_attach_type_by_name(prog_name, &attach_type)) { - log_err("Unexpected prog: %s", prog_name); + if (libbpf_attach_type_by_name(prog_name, &attach_type)) goto err; - } err = bpf_prog_attach(bpf_program__fd(prog), cgfd, attach_type, BPF_F_ALLOW_OVERRIDE); -- 2.30.2