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- // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
- /* Copyright (C) 2020 Facebook */
- #include <errno.h>
- #include <linux/err.h>
- #include <net/if.h>
- #include <stdio.h>
- #include <unistd.h>
- #include <bpf/bpf.h>
- #include <bpf/hashmap.h>
- #include "json_writer.h"
- #include "main.h"
- static struct hashmap *link_table;
- static int link_parse_fd(int *argc, char ***argv)
- {
- int fd;
- 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();
- fd = bpf_link_get_fd_by_id(id);
- if (fd < 0)
- p_err("failed to get link with ID %d: %s", id, strerror(errno));
- return fd;
- } 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)
- {
- const char *link_type_str;
- jsonw_uint_field(wtr, "id", info->id);
- link_type_str = libbpf_bpf_link_type_str(info->type);
- if (link_type_str)
- jsonw_string_field(wtr, "type", link_type_str);
- else
- jsonw_uint_field(wtr, "type", info->type);
- jsonw_uint_field(json_wtr, "prog_id", info->prog_id);
- }
- static void show_link_attach_type_json(__u32 attach_type, json_writer_t *wtr)
- {
- const char *attach_type_str;
- attach_type_str = libbpf_bpf_attach_type_str(attach_type);
- if (attach_type_str)
- jsonw_string_field(wtr, "attach_type", attach_type_str);
- else
- jsonw_uint_field(wtr, "attach_type", attach_type);
- }
- static bool is_iter_map_target(const char *target_name)
- {
- return strcmp(target_name, "bpf_map_elem") == 0 ||
- strcmp(target_name, "bpf_sk_storage_map") == 0;
- }
- static bool is_iter_cgroup_target(const char *target_name)
- {
- return strcmp(target_name, "cgroup") == 0;
- }
- static const char *cgroup_order_string(__u32 order)
- {
- switch (order) {
- case BPF_CGROUP_ITER_ORDER_UNSPEC:
- return "order_unspec";
- case BPF_CGROUP_ITER_SELF_ONLY:
- return "self_only";
- case BPF_CGROUP_ITER_DESCENDANTS_PRE:
- return "descendants_pre";
- case BPF_CGROUP_ITER_DESCENDANTS_POST:
- return "descendants_post";
- case BPF_CGROUP_ITER_ANCESTORS_UP:
- return "ancestors_up";
- default: /* won't happen */
- return "unknown";
- }
- }
- static bool is_iter_task_target(const char *target_name)
- {
- return strcmp(target_name, "task") == 0 ||
- strcmp(target_name, "task_file") == 0 ||
- strcmp(target_name, "task_vma") == 0;
- }
- static void show_iter_json(struct bpf_link_info *info, json_writer_t *wtr)
- {
- const char *target_name = u64_to_ptr(info->iter.target_name);
- jsonw_string_field(wtr, "target_name", target_name);
- if (is_iter_map_target(target_name))
- jsonw_uint_field(wtr, "map_id", info->iter.map.map_id);
- else if (is_iter_task_target(target_name)) {
- if (info->iter.task.tid)
- jsonw_uint_field(wtr, "tid", info->iter.task.tid);
- else if (info->iter.task.pid)
- jsonw_uint_field(wtr, "pid", info->iter.task.pid);
- }
- if (is_iter_cgroup_target(target_name)) {
- jsonw_lluint_field(wtr, "cgroup_id", info->iter.cgroup.cgroup_id);
- jsonw_string_field(wtr, "order",
- cgroup_order_string(info->iter.cgroup.order));
- }
- }
- 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;
- const char *prog_type_str;
- 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",
- u64_to_ptr(info->raw_tracepoint.tp_name));
- break;
- case BPF_LINK_TYPE_TRACING:
- err = get_prog_info(info->prog_id, &prog_info);
- if (err)
- return err;
- prog_type_str = libbpf_bpf_prog_type_str(prog_info.type);
- /* libbpf will return NULL for variants unknown to it. */
- if (prog_type_str)
- jsonw_string_field(json_wtr, "prog_type", prog_type_str);
- else
- jsonw_uint_field(json_wtr, "prog_type", prog_info.type);
- show_link_attach_type_json(info->tracing.attach_type,
- json_wtr);
- break;
- case BPF_LINK_TYPE_CGROUP:
- jsonw_lluint_field(json_wtr, "cgroup_id",
- info->cgroup.cgroup_id);
- show_link_attach_type_json(info->cgroup.attach_type, json_wtr);
- break;
- case BPF_LINK_TYPE_ITER:
- show_iter_json(info, json_wtr);
- break;
- case BPF_LINK_TYPE_NETNS:
- jsonw_uint_field(json_wtr, "netns_ino",
- info->netns.netns_ino);
- show_link_attach_type_json(info->netns.attach_type, json_wtr);
- break;
- default:
- break;
- }
- if (!hashmap__empty(link_table)) {
- struct hashmap_entry *entry;
- jsonw_name(json_wtr, "pinned");
- jsonw_start_array(json_wtr);
- hashmap__for_each_key_entry(link_table, entry,
- u32_as_hash_field(info->id))
- jsonw_string(json_wtr, entry->value);
- jsonw_end_array(json_wtr);
- }
- emit_obj_refs_json(refs_table, info->id, json_wtr);
- jsonw_end_object(json_wtr);
- return 0;
- }
- static void show_link_header_plain(struct bpf_link_info *info)
- {
- const char *link_type_str;
- printf("%u: ", info->id);
- link_type_str = libbpf_bpf_link_type_str(info->type);
- if (link_type_str)
- printf("%s ", link_type_str);
- else
- printf("type %u ", info->type);
- printf("prog %u ", info->prog_id);
- }
- static void show_link_attach_type_plain(__u32 attach_type)
- {
- const char *attach_type_str;
- attach_type_str = libbpf_bpf_attach_type_str(attach_type);
- if (attach_type_str)
- printf("attach_type %s ", attach_type_str);
- else
- printf("attach_type %u ", attach_type);
- }
- static void show_iter_plain(struct bpf_link_info *info)
- {
- const char *target_name = u64_to_ptr(info->iter.target_name);
- printf("target_name %s ", target_name);
- if (is_iter_map_target(target_name))
- printf("map_id %u ", info->iter.map.map_id);
- else if (is_iter_task_target(target_name)) {
- if (info->iter.task.tid)
- printf("tid %u ", info->iter.task.tid);
- else if (info->iter.task.pid)
- printf("pid %u ", info->iter.task.pid);
- }
- if (is_iter_cgroup_target(target_name)) {
- printf("cgroup_id %llu ", info->iter.cgroup.cgroup_id);
- printf("order %s ",
- cgroup_order_string(info->iter.cgroup.order));
- }
- }
- static int show_link_close_plain(int fd, struct bpf_link_info *info)
- {
- struct bpf_prog_info prog_info;
- const char *prog_type_str;
- int err;
- show_link_header_plain(info);
- switch (info->type) {
- case BPF_LINK_TYPE_RAW_TRACEPOINT:
- printf("\n\ttp '%s' ",
- (const char *)u64_to_ptr(info->raw_tracepoint.tp_name));
- break;
- case BPF_LINK_TYPE_TRACING:
- err = get_prog_info(info->prog_id, &prog_info);
- if (err)
- return err;
- prog_type_str = libbpf_bpf_prog_type_str(prog_info.type);
- /* libbpf will return NULL for variants unknown to it. */
- if (prog_type_str)
- printf("\n\tprog_type %s ", prog_type_str);
- else
- printf("\n\tprog_type %u ", prog_info.type);
- show_link_attach_type_plain(info->tracing.attach_type);
- break;
- case BPF_LINK_TYPE_CGROUP:
- printf("\n\tcgroup_id %zu ", (size_t)info->cgroup.cgroup_id);
- show_link_attach_type_plain(info->cgroup.attach_type);
- break;
- case BPF_LINK_TYPE_ITER:
- show_iter_plain(info);
- break;
- case BPF_LINK_TYPE_NETNS:
- printf("\n\tnetns_ino %u ", info->netns.netns_ino);
- show_link_attach_type_plain(info->netns.attach_type);
- break;
- default:
- break;
- }
- if (!hashmap__empty(link_table)) {
- struct hashmap_entry *entry;
- hashmap__for_each_key_entry(link_table, entry,
- u32_as_hash_field(info->id))
- printf("\n\tpinned %s", (char *)entry->value);
- }
- emit_obj_refs_plain(refs_table, info->id, "\n\tpids ");
- printf("\n");
- return 0;
- }
- static int do_show_link(int fd)
- {
- struct bpf_link_info info;
- __u32 len = sizeof(info);
- char buf[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)&buf;
- info.raw_tracepoint.tp_name_len = sizeof(buf);
- goto again;
- }
- if (info.type == BPF_LINK_TYPE_ITER &&
- !info.iter.target_name) {
- info.iter.target_name = (unsigned long)&buf;
- info.iter.target_name_len = sizeof(buf);
- 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) {
- link_table = hashmap__new(hash_fn_for_key_as_id,
- equal_fn_for_key_as_id, NULL);
- if (IS_ERR(link_table)) {
- p_err("failed to create hashmap for pinned paths");
- return -1;
- }
- build_pinned_obj_table(link_table, BPF_OBJ_LINK);
- }
- build_obj_refs_table(&refs_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);
- delete_obj_refs_table(refs_table);
- if (show_pinned)
- delete_pinned_obj_table(link_table);
- 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_detach(int argc, char **argv)
- {
- int err, fd;
- if (argc != 2) {
- p_err("link specifier is invalid or missing\n");
- return 1;
- }
- fd = link_parse_fd(&argc, &argv);
- if (fd < 0)
- return 1;
- err = bpf_link_detach(fd);
- if (err)
- err = -errno;
- close(fd);
- if (err) {
- p_err("failed link detach: %s", strerror(-err));
- return 1;
- }
- if (json_output)
- jsonw_null(json_wtr);
- return 0;
- }
- 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 detach LINK\n"
- " %1$s %2$s help\n"
- "\n"
- " " HELP_SPEC_LINK "\n"
- " " HELP_SPEC_OPTIONS " |\n"
- " {-f|--bpffs} | {-n|--nomount} }\n"
- "",
- bin_name, argv[-2]);
- return 0;
- }
- static const struct cmd cmds[] = {
- { "show", do_show },
- { "list", do_show },
- { "help", do_help },
- { "pin", do_pin },
- { "detach", do_detach },
- { 0 }
- };
- int do_link(int argc, char **argv)
- {
- return cmd_select(cmds, argc, argv, do_help);
- }
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