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