Commit c76e4c22 authored by Taeung Song's avatar Taeung Song Committed by Daniel Borkmann

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: default avatarTaeung Song <treeze.taeung@gmail.com>
Cc: Quentin Monnet <quentin.monnet@netronome.com>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Andrey Ignatov <rdna@fb.com>
Reviewed-by: default avatarQuentin Monnet <quentin.monnet@netronome.com>
Acked-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent ffcf7ce9
......@@ -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;
......@@ -1028,12 +1027,9 @@ 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);
bpf_program__set_type(pos, prog_type);
......
......@@ -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;
}
......
......@@ -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);
......
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