bpftool: Add bpf_link show and pin support
Add `bpftool link show` and `bpftool link pin` commands.
Example plain output for `link show` (with showing pinned paths):
[vmuser@archvm bpf]$ sudo ~/local/linux/tools/bpf/bpftool/bpftool -f link
1: tracing prog 12
prog_type tracing attach_type fentry
pinned /sys/fs/bpf/my_test_link
pinned /sys/fs/bpf/my_test_link2
2: tracing prog 13
prog_type tracing attach_type fentry
3: tracing prog 14
prog_type tracing attach_type fentry
4: tracing prog 15
prog_type tracing attach_type fentry
5: tracing prog 16
prog_type tracing attach_type fentry
6: tracing prog 17
prog_type tracing attach_type fentry
7: raw_tracepoint prog 21
tp 'sys_enter'
8: cgroup prog 25
cgroup_id 584 attach_type egress
9: cgroup prog 25
cgroup_id 599 attach_type egress
10: cgroup prog 25
cgroup_id 614 attach_type egress
11: cgroup prog 25
cgroup_id 629 attach_type egress
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20200429001614.1544-9-andriin@fb.com
This commit is contained in:
Andrii Nakryiko
Alexei Starovoitov
parent
50325b1761
commit
c5481f9a95
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@ -262,6 +262,8 @@ int get_fd_type(int fd)
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return BPF_OBJ_MAP;
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else if (strstr(buf, "bpf-prog"))
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return BPF_OBJ_PROG;
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else if (strstr(buf, "bpf-link"))
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return BPF_OBJ_LINK;
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return BPF_OBJ_UNKNOWN;
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}
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@ -0,0 +1,333 @@
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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
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/* Copyright (C) 2020 Facebook */
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#include <errno.h>
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#include <net/if.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <bpf/bpf.h>
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#include "json_writer.h"
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#include "main.h"
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static const char * const link_type_name[] = {
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[BPF_LINK_TYPE_UNSPEC] = "unspec",
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[BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
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[BPF_LINK_TYPE_TRACING] = "tracing",
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[BPF_LINK_TYPE_CGROUP] = "cgroup",
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};
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static int link_parse_fd(int *argc, char ***argv)
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{
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if (is_prefix(**argv, "id")) {
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unsigned int id;
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char *endptr;
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NEXT_ARGP();
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id = strtoul(**argv, &endptr, 0);
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if (*endptr) {
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p_err("can't parse %s as ID", **argv);
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return -1;
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}
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NEXT_ARGP();
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return bpf_link_get_fd_by_id(id);
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} else if (is_prefix(**argv, "pinned")) {
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char *path;
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NEXT_ARGP();
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path = **argv;
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NEXT_ARGP();
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return open_obj_pinned_any(path, BPF_OBJ_LINK);
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}
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p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
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return -1;
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}
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static void
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show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr)
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{
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jsonw_uint_field(wtr, "id", info->id);
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if (info->type < ARRAY_SIZE(link_type_name))
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jsonw_string_field(wtr, "type", link_type_name[info->type]);
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else
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jsonw_uint_field(wtr, "type", info->type);
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jsonw_uint_field(json_wtr, "prog_id", info->prog_id);
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}
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static int get_prog_info(int prog_id, struct bpf_prog_info *info)
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{
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__u32 len = sizeof(*info);
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int err, prog_fd;
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prog_fd = bpf_prog_get_fd_by_id(prog_id);
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if (prog_fd < 0)
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return prog_fd;
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memset(info, 0, sizeof(*info));
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err = bpf_obj_get_info_by_fd(prog_fd, info, &len);
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if (err)
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p_err("can't get prog info: %s", strerror(errno));
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close(prog_fd);
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return err;
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}
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static int show_link_close_json(int fd, struct bpf_link_info *info)
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{
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struct bpf_prog_info prog_info;
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int err;
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jsonw_start_object(json_wtr);
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show_link_header_json(info, json_wtr);
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switch (info->type) {
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case BPF_LINK_TYPE_RAW_TRACEPOINT:
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jsonw_string_field(json_wtr, "tp_name",
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(const char *)info->raw_tracepoint.tp_name);
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break;
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case BPF_LINK_TYPE_TRACING:
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err = get_prog_info(info->prog_id, &prog_info);
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if (err)
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return err;
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if (prog_info.type < ARRAY_SIZE(prog_type_name))
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jsonw_string_field(json_wtr, "prog_type",
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prog_type_name[prog_info.type]);
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else
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jsonw_uint_field(json_wtr, "prog_type",
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prog_info.type);
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if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name))
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jsonw_string_field(json_wtr, "attach_type",
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attach_type_name[info->tracing.attach_type]);
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else
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jsonw_uint_field(json_wtr, "attach_type",
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info->tracing.attach_type);
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break;
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case BPF_LINK_TYPE_CGROUP:
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jsonw_lluint_field(json_wtr, "cgroup_id",
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info->cgroup.cgroup_id);
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if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name))
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jsonw_string_field(json_wtr, "attach_type",
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attach_type_name[info->cgroup.attach_type]);
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else
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jsonw_uint_field(json_wtr, "attach_type",
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info->cgroup.attach_type);
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break;
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default:
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break;
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}
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if (!hash_empty(link_table.table)) {
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struct pinned_obj *obj;
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jsonw_name(json_wtr, "pinned");
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jsonw_start_array(json_wtr);
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hash_for_each_possible(link_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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jsonw_string(json_wtr, obj->path);
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}
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jsonw_end_array(json_wtr);
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}
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jsonw_end_object(json_wtr);
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return 0;
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}
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static void show_link_header_plain(struct bpf_link_info *info)
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{
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printf("%u: ", info->id);
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if (info->type < ARRAY_SIZE(link_type_name))
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printf("%s ", link_type_name[info->type]);
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else
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printf("type %u ", info->type);
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printf("prog %u ", info->prog_id);
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}
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static int show_link_close_plain(int fd, struct bpf_link_info *info)
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{
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struct bpf_prog_info prog_info;
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int err;
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show_link_header_plain(info);
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switch (info->type) {
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case BPF_LINK_TYPE_RAW_TRACEPOINT:
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printf("\n\ttp '%s' ",
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(const char *)info->raw_tracepoint.tp_name);
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break;
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case BPF_LINK_TYPE_TRACING:
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err = get_prog_info(info->prog_id, &prog_info);
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if (err)
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return err;
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if (prog_info.type < ARRAY_SIZE(prog_type_name))
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printf("\n\tprog_type %s ",
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prog_type_name[prog_info.type]);
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else
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printf("\n\tprog_type %u ", prog_info.type);
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if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name))
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printf("attach_type %s ",
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attach_type_name[info->tracing.attach_type]);
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else
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printf("attach_type %u ", info->tracing.attach_type);
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break;
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case BPF_LINK_TYPE_CGROUP:
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printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
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if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name))
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printf("attach_type %s ",
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attach_type_name[info->cgroup.attach_type]);
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else
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printf("attach_type %u ", info->cgroup.attach_type);
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break;
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default:
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break;
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}
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if (!hash_empty(link_table.table)) {
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struct pinned_obj *obj;
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hash_for_each_possible(link_table.table, obj, hash, info->id) {
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if (obj->id == info->id)
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printf("\n\tpinned %s", obj->path);
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}
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}
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printf("\n");
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return 0;
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}
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static int do_show_link(int fd)
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{
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struct bpf_link_info info;
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__u32 len = sizeof(info);
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char raw_tp_name[256];
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int err;
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memset(&info, 0, sizeof(info));
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again:
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err = bpf_obj_get_info_by_fd(fd, &info, &len);
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if (err) {
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p_err("can't get link info: %s",
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strerror(errno));
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close(fd);
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return err;
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}
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if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&
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!info.raw_tracepoint.tp_name) {
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info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name;
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info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name);
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goto again;
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}
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if (json_output)
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show_link_close_json(fd, &info);
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else
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show_link_close_plain(fd, &info);
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close(fd);
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return 0;
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}
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static int do_show(int argc, char **argv)
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{
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__u32 id = 0;
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int err, fd;
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if (show_pinned)
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build_pinned_obj_table(&link_table, BPF_OBJ_LINK);
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if (argc == 2) {
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fd = link_parse_fd(&argc, &argv);
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if (fd < 0)
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return fd;
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return do_show_link(fd);
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}
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if (argc)
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return BAD_ARG();
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if (json_output)
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jsonw_start_array(json_wtr);
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while (true) {
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err = bpf_link_get_next_id(id, &id);
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if (err) {
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if (errno == ENOENT)
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break;
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p_err("can't get next link: %s%s", strerror(errno),
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errno == EINVAL ? " -- kernel too old?" : "");
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break;
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}
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fd = bpf_link_get_fd_by_id(id);
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if (fd < 0) {
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if (errno == ENOENT)
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continue;
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p_err("can't get link by id (%u): %s",
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id, strerror(errno));
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break;
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}
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err = do_show_link(fd);
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if (err)
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break;
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}
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if (json_output)
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jsonw_end_array(json_wtr);
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return errno == ENOENT ? 0 : -1;
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}
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static int do_pin(int argc, char **argv)
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{
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int err;
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err = do_pin_any(argc, argv, link_parse_fd);
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if (!err && json_output)
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jsonw_null(json_wtr);
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return err;
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}
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static int do_help(int argc, char **argv)
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{
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if (json_output) {
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jsonw_null(json_wtr);
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return 0;
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}
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fprintf(stderr,
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"Usage: %1$s %2$s { show | list } [LINK]\n"
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" %1$s %2$s pin LINK FILE\n"
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" %1$s %2$s help\n"
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"\n"
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" " HELP_SPEC_LINK "\n"
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" " HELP_SPEC_PROGRAM "\n"
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" " HELP_SPEC_OPTIONS "\n"
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"",
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bin_name, argv[-2]);
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return 0;
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}
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static const struct cmd cmds[] = {
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{ "show", do_show },
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{ "list", do_show },
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{ "help", do_help },
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{ "pin", do_pin },
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{ 0 }
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};
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int do_link(int argc, char **argv)
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{
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return cmd_select(cmds, argc, argv, do_help);
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}
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@ -30,6 +30,7 @@ bool verifier_logs;
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bool relaxed_maps;
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struct pinned_obj_table prog_table;
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struct pinned_obj_table map_table;
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struct pinned_obj_table link_table;
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static void __noreturn clean_and_exit(int i)
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{
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@ -58,7 +59,7 @@ static int do_help(int argc, char **argv)
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" %s batch file FILE\n"
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" %s version\n"
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"\n"
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" OBJECT := { prog | map | cgroup | perf | net | feature | btf | gen | struct_ops }\n"
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" OBJECT := { prog | map | link | cgroup | perf | net | feature | btf | gen | struct_ops }\n"
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" " HELP_SPEC_OPTIONS "\n"
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"",
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bin_name, bin_name, bin_name);
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@ -215,6 +216,7 @@ static const struct cmd cmds[] = {
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{ "batch", do_batch },
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{ "prog", do_prog },
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{ "map", do_map },
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{ "link", do_link },
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{ "cgroup", do_cgroup },
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{ "perf", do_perf },
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{ "net", do_net },
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@ -364,6 +366,7 @@ int main(int argc, char **argv)
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hash_init(prog_table.table);
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hash_init(map_table.table);
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hash_init(link_table.table);
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opterr = 0;
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while ((opt = getopt_long(argc, argv, "Vhpjfmnd",
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@ -422,6 +425,7 @@ int main(int argc, char **argv)
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if (show_pinned) {
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delete_pinned_obj_table(&prog_table);
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delete_pinned_obj_table(&map_table);
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delete_pinned_obj_table(&link_table);
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}
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return ret;
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@ -50,6 +50,8 @@
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"\t {-m|--mapcompat} | {-n|--nomount} }"
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#define HELP_SPEC_MAP \
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"MAP := { id MAP_ID | pinned FILE | name MAP_NAME }"
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#define HELP_SPEC_LINK \
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"LINK := { id LINK_ID | pinned FILE }"
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static const char * const prog_type_name[] = {
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[BPF_PROG_TYPE_UNSPEC] = "unspec",
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@ -122,6 +124,7 @@ enum bpf_obj_type {
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BPF_OBJ_UNKNOWN,
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BPF_OBJ_PROG,
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BPF_OBJ_MAP,
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BPF_OBJ_LINK,
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};
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extern const char *bin_name;
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@ -134,6 +137,7 @@ extern bool verifier_logs;
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extern bool relaxed_maps;
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extern struct pinned_obj_table prog_table;
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extern struct pinned_obj_table map_table;
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extern struct pinned_obj_table link_table;
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void __printf(1, 2) p_err(const char *fmt, ...);
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void __printf(1, 2) p_info(const char *fmt, ...);
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@ -185,6 +189,7 @@ int do_pin_fd(int fd, const char *name);
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int do_prog(int argc, char **arg);
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int do_map(int argc, char **arg);
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int do_link(int argc, char **arg);
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int do_event_pipe(int argc, char **argv);
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int do_cgroup(int argc, char **arg);
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int do_perf(int argc, char **arg);
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