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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2020 Facebook */
#include <errno.h>
#include <net/if.h>
#include <stdio.h>
#include <unistd.h>
#include <bpf/bpf.h>
#include "json_writer.h"
#include "main.h"
static const char * const link_type_name[] = {
[BPF_LINK_TYPE_UNSPEC] = "unspec",
[BPF_LINK_TYPE_RAW_TRACEPOINT] = "raw_tracepoint",
[BPF_LINK_TYPE_TRACING] = "tracing",
[BPF_LINK_TYPE_CGROUP] = "cgroup",
};
static int link_parse_fd(int *argc, char ***argv)
{
if (is_prefix(**argv, "id")) {
unsigned int id;
char *endptr;
NEXT_ARGP();
id = strtoul(**argv, &endptr, 0);
if (*endptr) {
p_err("can't parse %s as ID", **argv);
return -1;
}
NEXT_ARGP();
return bpf_link_get_fd_by_id(id);
} else if (is_prefix(**argv, "pinned")) {
char *path;
NEXT_ARGP();
path = **argv;
NEXT_ARGP();
return open_obj_pinned_any(path, BPF_OBJ_LINK);
}
p_err("expected 'id' or 'pinned', got: '%s'?", **argv);
return -1;
}
static void
show_link_header_json(struct bpf_link_info *info, json_writer_t *wtr)
{
jsonw_uint_field(wtr, "id", info->id);
if (info->type < ARRAY_SIZE(link_type_name))
jsonw_string_field(wtr, "type", link_type_name[info->type]);
else
jsonw_uint_field(wtr, "type", info->type);
jsonw_uint_field(json_wtr, "prog_id", info->prog_id);
}
static int get_prog_info(int prog_id, struct bpf_prog_info *info)
{
__u32 len = sizeof(*info);
int err, prog_fd;
prog_fd = bpf_prog_get_fd_by_id(prog_id);
if (prog_fd < 0)
return prog_fd;
memset(info, 0, sizeof(*info));
err = bpf_obj_get_info_by_fd(prog_fd, info, &len);
if (err)
p_err("can't get prog info: %s", strerror(errno));
close(prog_fd);
return err;
}
static int show_link_close_json(int fd, struct bpf_link_info *info)
{
struct bpf_prog_info prog_info;
int err;
jsonw_start_object(json_wtr);
show_link_header_json(info, json_wtr);
switch (info->type) {
case BPF_LINK_TYPE_RAW_TRACEPOINT:
jsonw_string_field(json_wtr, "tp_name",
(const char *)info->raw_tracepoint.tp_name);
break;
case BPF_LINK_TYPE_TRACING:
err = get_prog_info(info->prog_id, &prog_info);
if (err)
return err;
if (prog_info.type < ARRAY_SIZE(prog_type_name))
jsonw_string_field(json_wtr, "prog_type",
prog_type_name[prog_info.type]);
else
jsonw_uint_field(json_wtr, "prog_type",
prog_info.type);
if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name))
jsonw_string_field(json_wtr, "attach_type",
attach_type_name[info->tracing.attach_type]);
else
jsonw_uint_field(json_wtr, "attach_type",
info->tracing.attach_type);
break;
case BPF_LINK_TYPE_CGROUP:
jsonw_lluint_field(json_wtr, "cgroup_id",
info->cgroup.cgroup_id);
if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name))
jsonw_string_field(json_wtr, "attach_type",
attach_type_name[info->cgroup.attach_type]);
else
jsonw_uint_field(json_wtr, "attach_type",
info->cgroup.attach_type);
break;
default:
break;
}
if (!hash_empty(link_table.table)) {
struct pinned_obj *obj;
jsonw_name(json_wtr, "pinned");
jsonw_start_array(json_wtr);
hash_for_each_possible(link_table.table, obj, hash, info->id) {
if (obj->id == info->id)
jsonw_string(json_wtr, obj->path);
}
jsonw_end_array(json_wtr);
}
jsonw_end_object(json_wtr);
return 0;
}
static void show_link_header_plain(struct bpf_link_info *info)
{
printf("%u: ", info->id);
if (info->type < ARRAY_SIZE(link_type_name))
printf("%s ", link_type_name[info->type]);
else
printf("type %u ", info->type);
printf("prog %u ", info->prog_id);
}
static int show_link_close_plain(int fd, struct bpf_link_info *info)
{
struct bpf_prog_info prog_info;
int err;
show_link_header_plain(info);
switch (info->type) {
case BPF_LINK_TYPE_RAW_TRACEPOINT:
printf("\n\ttp '%s' ",
(const char *)info->raw_tracepoint.tp_name);
break;
case BPF_LINK_TYPE_TRACING:
err = get_prog_info(info->prog_id, &prog_info);
if (err)
return err;
if (prog_info.type < ARRAY_SIZE(prog_type_name))
printf("\n\tprog_type %s ",
prog_type_name[prog_info.type]);
else
printf("\n\tprog_type %u ", prog_info.type);
if (info->tracing.attach_type < ARRAY_SIZE(attach_type_name))
printf("attach_type %s ",
attach_type_name[info->tracing.attach_type]);
else
printf("attach_type %u ", info->tracing.attach_type);
break;
case BPF_LINK_TYPE_CGROUP:
printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
if (info->cgroup.attach_type < ARRAY_SIZE(attach_type_name))
printf("attach_type %s ",
attach_type_name[info->cgroup.attach_type]);
else
printf("attach_type %u ", info->cgroup.attach_type);
break;
default:
break;
}
if (!hash_empty(link_table.table)) {
struct pinned_obj *obj;
hash_for_each_possible(link_table.table, obj, hash, info->id) {
if (obj->id == info->id)
printf("\n\tpinned %s", obj->path);
}
}
printf("\n");
return 0;
}
static int do_show_link(int fd)
{
struct bpf_link_info info;
__u32 len = sizeof(info);
char raw_tp_name[256];
int err;
memset(&info, 0, sizeof(info));
again:
err = bpf_obj_get_info_by_fd(fd, &info, &len);
if (err) {
p_err("can't get link info: %s",
strerror(errno));
close(fd);
return err;
}
if (info.type == BPF_LINK_TYPE_RAW_TRACEPOINT &&
!info.raw_tracepoint.tp_name) {
info.raw_tracepoint.tp_name = (unsigned long)&raw_tp_name;
info.raw_tracepoint.tp_name_len = sizeof(raw_tp_name);
goto again;
}
if (json_output)
show_link_close_json(fd, &info);
else
show_link_close_plain(fd, &info);
close(fd);
return 0;
}
static int do_show(int argc, char **argv)
{
__u32 id = 0;
int err, fd;
if (show_pinned)
build_pinned_obj_table(&link_table, BPF_OBJ_LINK);
if (argc == 2) {
fd = link_parse_fd(&argc, &argv);
if (fd < 0)
return fd;
return do_show_link(fd);
}
if (argc)
return BAD_ARG();
if (json_output)
jsonw_start_array(json_wtr);
while (true) {
err = bpf_link_get_next_id(id, &id);
if (err) {
if (errno == ENOENT)
break;
p_err("can't get next link: %s%s", strerror(errno),
errno == EINVAL ? " -- kernel too old?" : "");
break;
}
fd = bpf_link_get_fd_by_id(id);
if (fd < 0) {
if (errno == ENOENT)
continue;
p_err("can't get link by id (%u): %s",
id, strerror(errno));
break;
}
err = do_show_link(fd);
if (err)
break;
}
if (json_output)
jsonw_end_array(json_wtr);
return errno == ENOENT ? 0 : -1;
}
static int do_pin(int argc, char **argv)
{
int err;
err = do_pin_any(argc, argv, link_parse_fd);
if (!err && json_output)
jsonw_null(json_wtr);
return err;
}
static int do_help(int argc, char **argv)
{
if (json_output) {
jsonw_null(json_wtr);
return 0;
}
fprintf(stderr,
"Usage: %1$s %2$s { show | list } [LINK]\n"
" %1$s %2$s pin LINK FILE\n"
" %1$s %2$s help\n"
"\n"
" " HELP_SPEC_LINK "\n"
" " HELP_SPEC_PROGRAM "\n"
" " HELP_SPEC_OPTIONS "\n"
"",
bin_name, argv[-2]);
return 0;
}
static const struct cmd cmds[] = {
{ "show", do_show },
{ "list", do_show },
{ "help", do_help },
{ "pin", do_pin },
{ 0 }
};
int do_link(int argc, char **argv)
{
return cmd_select(cmds, argc, argv, do_help);
}
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