| // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) |
| /* Copyright (C) 2020 Facebook */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <unistd.h> |
| |
| #include <linux/err.h> |
| |
| #include <bpf/bpf.h> |
| #include <bpf/btf.h> |
| #include <bpf/libbpf.h> |
| |
| #include "json_writer.h" |
| #include "main.h" |
| |
| #define STRUCT_OPS_VALUE_PREFIX "bpf_struct_ops_" |
| |
| static const struct btf_type *map_info_type; |
| static __u32 map_info_alloc_len; |
| static struct btf *btf_vmlinux; |
| static __s32 map_info_type_id; |
| |
| struct res { |
| unsigned int nr_maps; |
| unsigned int nr_errs; |
| }; |
| |
| static const struct btf *get_btf_vmlinux(void) |
| { |
| if (btf_vmlinux) |
| return btf_vmlinux; |
| |
| btf_vmlinux = libbpf_find_kernel_btf(); |
| if (libbpf_get_error(btf_vmlinux)) |
| p_err("struct_ops requires kernel CONFIG_DEBUG_INFO_BTF=y"); |
| |
| return btf_vmlinux; |
| } |
| |
| static const char *get_kern_struct_ops_name(const struct bpf_map_info *info) |
| { |
| const struct btf *kern_btf; |
| const struct btf_type *t; |
| const char *st_ops_name; |
| |
| kern_btf = get_btf_vmlinux(); |
| if (libbpf_get_error(kern_btf)) |
| return "<btf_vmlinux_not_found>"; |
| |
| t = btf__type_by_id(kern_btf, info->btf_vmlinux_value_type_id); |
| st_ops_name = btf__name_by_offset(kern_btf, t->name_off); |
| st_ops_name += strlen(STRUCT_OPS_VALUE_PREFIX); |
| |
| return st_ops_name; |
| } |
| |
| static __s32 get_map_info_type_id(void) |
| { |
| const struct btf *kern_btf; |
| |
| if (map_info_type_id) |
| return map_info_type_id; |
| |
| kern_btf = get_btf_vmlinux(); |
| if (libbpf_get_error(kern_btf)) { |
| map_info_type_id = PTR_ERR(kern_btf); |
| return map_info_type_id; |
| } |
| |
| map_info_type_id = btf__find_by_name_kind(kern_btf, "bpf_map_info", |
| BTF_KIND_STRUCT); |
| if (map_info_type_id < 0) { |
| p_err("can't find bpf_map_info from btf_vmlinux"); |
| return map_info_type_id; |
| } |
| map_info_type = btf__type_by_id(kern_btf, map_info_type_id); |
| |
| /* Ensure map_info_alloc() has at least what the bpftool needs */ |
| map_info_alloc_len = map_info_type->size; |
| if (map_info_alloc_len < sizeof(struct bpf_map_info)) |
| map_info_alloc_len = sizeof(struct bpf_map_info); |
| |
| return map_info_type_id; |
| } |
| |
| /* If the subcmd needs to print out the bpf_map_info, |
| * it should always call map_info_alloc to allocate |
| * a bpf_map_info object instead of allocating it |
| * on the stack. |
| * |
| * map_info_alloc() will take the running kernel's btf |
| * into account. i.e. it will consider the |
| * sizeof(struct bpf_map_info) of the running kernel. |
| * |
| * It will enable the "struct_ops" cmd to print the latest |
| * "struct bpf_map_info". |
| * |
| * [ Recall that "struct_ops" requires the kernel's btf to |
| * be available ] |
| */ |
| static struct bpf_map_info *map_info_alloc(__u32 *alloc_len) |
| { |
| struct bpf_map_info *info; |
| |
| if (get_map_info_type_id() < 0) |
| return NULL; |
| |
| info = calloc(1, map_info_alloc_len); |
| if (!info) |
| p_err("mem alloc failed"); |
| else |
| *alloc_len = map_info_alloc_len; |
| |
| return info; |
| } |
| |
| /* It iterates all struct_ops maps of the system. |
| * It returns the fd in "*res_fd" and map_info in "*info". |
| * In the very first iteration, info->id should be 0. |
| * An optional map "*name" filter can be specified. |
| * The filter can be made more flexible in the future. |
| * e.g. filter by kernel-struct-ops-name, regex-name, glob-name, ...etc. |
| * |
| * Return value: |
| * 1: A struct_ops map found. It is returned in "*res_fd" and "*info". |
| * The caller can continue to call get_next in the future. |
| * 0: No struct_ops map is returned. |
| * All struct_ops map has been found. |
| * -1: Error and the caller should abort the iteration. |
| */ |
| static int get_next_struct_ops_map(const char *name, int *res_fd, |
| struct bpf_map_info *info, __u32 info_len) |
| { |
| __u32 id = info->id; |
| int err, fd; |
| |
| while (true) { |
| err = bpf_map_get_next_id(id, &id); |
| if (err) { |
| if (errno == ENOENT) |
| return 0; |
| p_err("can't get next map: %s", strerror(errno)); |
| return -1; |
| } |
| |
| fd = bpf_map_get_fd_by_id(id); |
| if (fd < 0) { |
| if (errno == ENOENT) |
| continue; |
| p_err("can't get map by id (%u): %s", |
| id, strerror(errno)); |
| return -1; |
| } |
| |
| err = bpf_obj_get_info_by_fd(fd, info, &info_len); |
| if (err) { |
| p_err("can't get map info: %s", strerror(errno)); |
| close(fd); |
| return -1; |
| } |
| |
| if (info->type == BPF_MAP_TYPE_STRUCT_OPS && |
| (!name || !strcmp(name, info->name))) { |
| *res_fd = fd; |
| return 1; |
| } |
| close(fd); |
| } |
| } |
| |
| static int cmd_retval(const struct res *res, bool must_have_one_map) |
| { |
| if (res->nr_errs || (!res->nr_maps && must_have_one_map)) |
| return -1; |
| |
| return 0; |
| } |
| |
| /* "data" is the work_func private storage */ |
| typedef int (*work_func)(int fd, const struct bpf_map_info *info, void *data, |
| struct json_writer *wtr); |
| |
| /* Find all struct_ops map in the system. |
| * Filter out by "name" (if specified). |
| * Then call "func(fd, info, data, wtr)" on each struct_ops map found. |
| */ |
| static struct res do_search(const char *name, work_func func, void *data, |
| struct json_writer *wtr) |
| { |
| struct bpf_map_info *info; |
| struct res res = {}; |
| __u32 info_len; |
| int fd, err; |
| |
| info = map_info_alloc(&info_len); |
| if (!info) { |
| res.nr_errs++; |
| return res; |
| } |
| |
| if (wtr) |
| jsonw_start_array(wtr); |
| while ((err = get_next_struct_ops_map(name, &fd, info, info_len)) == 1) { |
| res.nr_maps++; |
| err = func(fd, info, data, wtr); |
| if (err) |
| res.nr_errs++; |
| close(fd); |
| } |
| if (wtr) |
| jsonw_end_array(wtr); |
| |
| if (err) |
| res.nr_errs++; |
| |
| if (!wtr && name && !res.nr_errs && !res.nr_maps) |
| /* It is not printing empty []. |
| * Thus, needs to specifically say nothing found |
| * for "name" here. |
| */ |
| p_err("no struct_ops found for %s", name); |
| else if (!wtr && json_output && !res.nr_errs) |
| /* The "func()" above is not writing any json (i.e. !wtr |
| * test here). |
| * |
| * However, "-j" is enabled and there is no errs here, |
| * so call json_null() as the current convention of |
| * other cmds. |
| */ |
| jsonw_null(json_wtr); |
| |
| free(info); |
| return res; |
| } |
| |
| static struct res do_one_id(const char *id_str, work_func func, void *data, |
| struct json_writer *wtr) |
| { |
| struct bpf_map_info *info; |
| struct res res = {}; |
| unsigned long id; |
| __u32 info_len; |
| char *endptr; |
| int fd; |
| |
| id = strtoul(id_str, &endptr, 0); |
| if (*endptr || !id || id > UINT32_MAX) { |
| p_err("invalid id %s", id_str); |
| res.nr_errs++; |
| return res; |
| } |
| |
| fd = bpf_map_get_fd_by_id(id); |
| if (fd < 0) { |
| p_err("can't get map by id (%lu): %s", id, strerror(errno)); |
| res.nr_errs++; |
| return res; |
| } |
| |
| info = map_info_alloc(&info_len); |
| if (!info) { |
| res.nr_errs++; |
| goto done; |
| } |
| |
| if (bpf_obj_get_info_by_fd(fd, info, &info_len)) { |
| p_err("can't get map info: %s", strerror(errno)); |
| res.nr_errs++; |
| goto done; |
| } |
| |
| if (info->type != BPF_MAP_TYPE_STRUCT_OPS) { |
| p_err("%s id %u is not a struct_ops map", info->name, info->id); |
| res.nr_errs++; |
| goto done; |
| } |
| |
| res.nr_maps++; |
| |
| if (func(fd, info, data, wtr)) |
| res.nr_errs++; |
| else if (!wtr && json_output) |
| /* The "func()" above is not writing any json (i.e. !wtr |
| * test here). |
| * |
| * However, "-j" is enabled and there is no errs here, |
| * so call json_null() as the current convention of |
| * other cmds. |
| */ |
| jsonw_null(json_wtr); |
| |
| done: |
| free(info); |
| close(fd); |
| |
| return res; |
| } |
| |
| static struct res do_work_on_struct_ops(const char *search_type, |
| const char *search_term, |
| work_func func, void *data, |
| struct json_writer *wtr) |
| { |
| if (search_type) { |
| if (is_prefix(search_type, "id")) |
| return do_one_id(search_term, func, data, wtr); |
| else if (!is_prefix(search_type, "name")) |
| usage(); |
| } |
| |
| return do_search(search_term, func, data, wtr); |
| } |
| |
| static int __do_show(int fd, const struct bpf_map_info *info, void *data, |
| struct json_writer *wtr) |
| { |
| if (wtr) { |
| jsonw_start_object(wtr); |
| jsonw_uint_field(wtr, "id", info->id); |
| jsonw_string_field(wtr, "name", info->name); |
| jsonw_string_field(wtr, "kernel_struct_ops", |
| get_kern_struct_ops_name(info)); |
| jsonw_end_object(wtr); |
| } else { |
| printf("%u: %-15s %-32s\n", info->id, info->name, |
| get_kern_struct_ops_name(info)); |
| } |
| |
| return 0; |
| } |
| |
| static int do_show(int argc, char **argv) |
| { |
| const char *search_type = NULL, *search_term = NULL; |
| struct res res; |
| |
| if (argc && argc != 2) |
| usage(); |
| |
| if (argc == 2) { |
| search_type = GET_ARG(); |
| search_term = GET_ARG(); |
| } |
| |
| res = do_work_on_struct_ops(search_type, search_term, __do_show, |
| NULL, json_wtr); |
| |
| return cmd_retval(&res, !!search_term); |
| } |
| |
| static int __do_dump(int fd, const struct bpf_map_info *info, void *data, |
| struct json_writer *wtr) |
| { |
| struct btf_dumper *d = (struct btf_dumper *)data; |
| const struct btf_type *struct_ops_type; |
| const struct btf *kern_btf = d->btf; |
| const char *struct_ops_name; |
| int zero = 0; |
| void *value; |
| |
| /* note: d->jw == wtr */ |
| |
| kern_btf = d->btf; |
| |
| /* The kernel supporting BPF_MAP_TYPE_STRUCT_OPS must have |
| * btf_vmlinux_value_type_id. |
| */ |
| struct_ops_type = btf__type_by_id(kern_btf, |
| info->btf_vmlinux_value_type_id); |
| struct_ops_name = btf__name_by_offset(kern_btf, |
| struct_ops_type->name_off); |
| value = calloc(1, info->value_size); |
| if (!value) { |
| p_err("mem alloc failed"); |
| return -1; |
| } |
| |
| if (bpf_map_lookup_elem(fd, &zero, value)) { |
| p_err("can't lookup struct_ops map %s id %u", |
| info->name, info->id); |
| free(value); |
| return -1; |
| } |
| |
| jsonw_start_object(wtr); |
| jsonw_name(wtr, "bpf_map_info"); |
| btf_dumper_type(d, map_info_type_id, (void *)info); |
| jsonw_end_object(wtr); |
| |
| jsonw_start_object(wtr); |
| jsonw_name(wtr, struct_ops_name); |
| btf_dumper_type(d, info->btf_vmlinux_value_type_id, value); |
| jsonw_end_object(wtr); |
| |
| free(value); |
| |
| return 0; |
| } |
| |
| static int do_dump(int argc, char **argv) |
| { |
| const char *search_type = NULL, *search_term = NULL; |
| json_writer_t *wtr = json_wtr; |
| const struct btf *kern_btf; |
| struct btf_dumper d = {}; |
| struct res res; |
| |
| if (argc && argc != 2) |
| usage(); |
| |
| if (argc == 2) { |
| search_type = GET_ARG(); |
| search_term = GET_ARG(); |
| } |
| |
| kern_btf = get_btf_vmlinux(); |
| if (libbpf_get_error(kern_btf)) |
| return -1; |
| |
| if (!json_output) { |
| wtr = jsonw_new(stdout); |
| if (!wtr) { |
| p_err("can't create json writer"); |
| return -1; |
| } |
| jsonw_pretty(wtr, true); |
| } |
| |
| d.btf = kern_btf; |
| d.jw = wtr; |
| d.is_plain_text = !json_output; |
| d.prog_id_as_func_ptr = true; |
| |
| res = do_work_on_struct_ops(search_type, search_term, __do_dump, &d, |
| wtr); |
| |
| if (!json_output) |
| jsonw_destroy(&wtr); |
| |
| return cmd_retval(&res, !!search_term); |
| } |
| |
| static int __do_unregister(int fd, const struct bpf_map_info *info, void *data, |
| struct json_writer *wtr) |
| { |
| int zero = 0; |
| |
| if (bpf_map_delete_elem(fd, &zero)) { |
| p_err("can't unload %s %s id %u: %s", |
| get_kern_struct_ops_name(info), info->name, |
| info->id, strerror(errno)); |
| return -1; |
| } |
| |
| p_info("Unregistered %s %s id %u", |
| get_kern_struct_ops_name(info), info->name, |
| info->id); |
| |
| return 0; |
| } |
| |
| static int do_unregister(int argc, char **argv) |
| { |
| const char *search_type, *search_term; |
| struct res res; |
| |
| if (argc != 2) |
| usage(); |
| |
| search_type = GET_ARG(); |
| search_term = GET_ARG(); |
| |
| res = do_work_on_struct_ops(search_type, search_term, |
| __do_unregister, NULL, NULL); |
| |
| return cmd_retval(&res, true); |
| } |
| |
| static int do_register(int argc, char **argv) |
| { |
| LIBBPF_OPTS(bpf_object_open_opts, open_opts); |
| struct bpf_map_info info = {}; |
| __u32 info_len = sizeof(info); |
| int nr_errs = 0, nr_maps = 0; |
| struct bpf_object *obj; |
| struct bpf_link *link; |
| struct bpf_map *map; |
| const char *file; |
| |
| if (argc != 1) |
| usage(); |
| |
| file = GET_ARG(); |
| |
| if (verifier_logs) |
| /* log_level1 + log_level2 + stats, but not stable UAPI */ |
| open_opts.kernel_log_level = 1 + 2 + 4; |
| |
| obj = bpf_object__open_file(file, &open_opts); |
| if (libbpf_get_error(obj)) |
| return -1; |
| |
| set_max_rlimit(); |
| |
| if (bpf_object__load(obj)) { |
| bpf_object__close(obj); |
| return -1; |
| } |
| |
| bpf_object__for_each_map(map, obj) { |
| if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS) |
| continue; |
| |
| link = bpf_map__attach_struct_ops(map); |
| if (libbpf_get_error(link)) { |
| p_err("can't register struct_ops %s: %s", |
| bpf_map__name(map), |
| strerror(-PTR_ERR(link))); |
| nr_errs++; |
| continue; |
| } |
| nr_maps++; |
| |
| bpf_link__disconnect(link); |
| bpf_link__destroy(link); |
| |
| if (!bpf_obj_get_info_by_fd(bpf_map__fd(map), &info, |
| &info_len)) |
| p_info("Registered %s %s id %u", |
| get_kern_struct_ops_name(&info), |
| bpf_map__name(map), |
| info.id); |
| else |
| /* Not p_err. The struct_ops was attached |
| * successfully. |
| */ |
| p_info("Registered %s but can't find id: %s", |
| bpf_map__name(map), strerror(errno)); |
| } |
| |
| bpf_object__close(obj); |
| |
| if (nr_errs) |
| return -1; |
| |
| if (!nr_maps) { |
| p_err("no struct_ops found in %s", file); |
| 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 } [STRUCT_OPS_MAP]\n" |
| " %1$s %2$s dump [STRUCT_OPS_MAP]\n" |
| " %1$s %2$s register OBJ\n" |
| " %1$s %2$s unregister STRUCT_OPS_MAP\n" |
| " %1$s %2$s help\n" |
| "\n" |
| " STRUCT_OPS_MAP := [ id STRUCT_OPS_MAP_ID | name STRUCT_OPS_MAP_NAME ]\n" |
| " " HELP_SPEC_OPTIONS " }\n" |
| "", |
| bin_name, argv[-2]); |
| |
| return 0; |
| } |
| |
| static const struct cmd cmds[] = { |
| { "show", do_show }, |
| { "list", do_show }, |
| { "register", do_register }, |
| { "unregister", do_unregister }, |
| { "dump", do_dump }, |
| { "help", do_help }, |
| { 0 } |
| }; |
| |
| int do_struct_ops(int argc, char **argv) |
| { |
| int err; |
| |
| err = cmd_select(cmds, argc, argv, do_help); |
| |
| if (!libbpf_get_error(btf_vmlinux)) |
| btf__free(btf_vmlinux); |
| |
| return err; |
| } |