sanitize_identifier(name);
}
-static void get_header_guard(char *guard, const char *obj_name)
+static void get_header_guard(char *guard, const char *obj_name, const char *suffix)
{
int i;
- sprintf(guard, "__%s_SKEL_H__", obj_name);
+ sprintf(guard, "__%s_%s__", obj_name, suffix);
for (i = 0; guard[i]; i++)
guard[i] = toupper(guard[i]);
}
return NULL;
}
+static bool is_internal_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
+{
+ if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
+ return false;
+
+ if (!get_map_ident(map, buf, sz))
+ return false;
+
+ return true;
+}
+
static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
{
struct btf *btf = bpf_object__btf(obj);
bpf_object__for_each_map(map, obj) {
/* only generate definitions for memory-mapped internal maps */
- if (!bpf_map__is_internal(map))
- continue;
- if (!(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
- continue;
-
- if (!get_map_ident(map, map_ident, sizeof(map_ident)))
+ if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
continue;
sec = find_type_for_map(btf, map_ident);
return err;
}
+static bool btf_is_ptr_to_func_proto(const struct btf *btf,
+ const struct btf_type *v)
+{
+ return btf_is_ptr(v) && btf_is_func_proto(btf__type_by_id(btf, v->type));
+}
+
+static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name)
+{
+ struct btf *btf = bpf_object__btf(obj);
+ struct btf_dump *d;
+ struct bpf_map *map;
+ const struct btf_type *sec, *var;
+ const struct btf_var_secinfo *sec_var;
+ int i, err = 0, vlen;
+ char map_ident[256], sec_ident[256];
+ bool strip_mods = false, needs_typeof = false;
+ const char *sec_name, *var_name;
+ __u32 var_type_id;
+
+ d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL);
+ if (!d)
+ return -errno;
+
+ bpf_object__for_each_map(map, obj) {
+ /* only generate definitions for memory-mapped internal maps */
+ if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
+ continue;
+
+ sec = find_type_for_map(btf, map_ident);
+ if (!sec)
+ continue;
+
+ sec_name = btf__name_by_offset(btf, sec->name_off);
+ if (!get_datasec_ident(sec_name, sec_ident, sizeof(sec_ident)))
+ continue;
+
+ strip_mods = strcmp(sec_name, ".kconfig") != 0;
+ printf(" struct %s__%s {\n", obj_name, sec_ident);
+
+ sec_var = btf_var_secinfos(sec);
+ vlen = btf_vlen(sec);
+ for (i = 0; i < vlen; i++, sec_var++) {
+ DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
+ .indent_level = 2,
+ .strip_mods = strip_mods,
+ /* we'll print the name separately */
+ .field_name = "",
+ );
+
+ var = btf__type_by_id(btf, sec_var->type);
+ var_name = btf__name_by_offset(btf, var->name_off);
+ var_type_id = var->type;
+
+ /* static variables are not exposed through BPF skeleton */
+ if (btf_var(var)->linkage == BTF_VAR_STATIC)
+ continue;
+
+ /* The datasec member has KIND_VAR but we want the
+ * underlying type of the variable (e.g. KIND_INT).
+ */
+ var = skip_mods_and_typedefs(btf, var->type, NULL);
+
+ printf("\t\t");
+ /* Func and array members require special handling.
+ * Instead of producing `typename *var`, they produce
+ * `typeof(typename) *var`. This allows us to keep a
+ * similar syntax where the identifier is just prefixed
+ * by *, allowing us to ignore C declaration minutiae.
+ */
+ needs_typeof = btf_is_array(var) || btf_is_ptr_to_func_proto(btf, var);
+ if (needs_typeof)
+ printf("typeof(");
+
+ err = btf_dump__emit_type_decl(d, var_type_id, &opts);
+ if (err)
+ goto out;
+
+ if (needs_typeof)
+ printf(")");
+
+ printf(" *%s;\n", var_name);
+ }
+ printf(" } %s;\n", sec_ident);
+ }
+
+out:
+ btf_dump__free(d);
+ return err;
+}
+
static void codegen(const char *template, ...)
{
const char *src, *end;
", obj_name);
bpf_object__for_each_map(map, obj) {
- if (!bpf_map__is_internal(map))
- continue;
- if (!(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
- continue;
- if (!get_map_ident(map, map_ident, sizeof(map_ident)))
+ if (!is_internal_mmapable_map(map, map_ident, sizeof(map_ident)))
continue;
sec = find_type_for_map(btf, map_ident);
const void *mmap_data = NULL;
size_t mmap_size = 0;
- if (!get_map_ident(map, ident, sizeof(ident)))
- continue;
-
- if (!bpf_map__is_internal(map) ||
- !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
+ if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
continue;
codegen("\
bpf_object__for_each_map(map, obj) {
const char *mmap_flags;
- if (!get_map_ident(map, ident, sizeof(ident)))
- continue;
-
- if (!bpf_map__is_internal(map) ||
- !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
+ if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
continue;
if (bpf_map__map_flags(map) & BPF_F_RDONLY_PROG)
return err;
}
+static void
+codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
+{
+ struct bpf_map *map;
+ char ident[256];
+ size_t i;
+
+ if (!map_cnt)
+ return;
+
+ codegen("\
+ \n\
+ \n\
+ /* maps */ \n\
+ s->map_cnt = %zu; \n\
+ s->map_skel_sz = sizeof(*s->maps); \n\
+ s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
+ if (!s->maps) \n\
+ goto err; \n\
+ ",
+ map_cnt
+ );
+ i = 0;
+ bpf_object__for_each_map(map, obj) {
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+
+ codegen("\
+ \n\
+ \n\
+ s->maps[%zu].name = \"%s\"; \n\
+ s->maps[%zu].map = &obj->maps.%s; \n\
+ ",
+ i, bpf_map__name(map), i, ident);
+ /* memory-mapped internal maps */
+ if (mmaped && is_internal_mmapable_map(map, ident, sizeof(ident))) {
+ printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
+ i, ident);
+ }
+ i++;
+ }
+}
+
+static void
+codegen_progs_skeleton(struct bpf_object *obj, size_t prog_cnt, bool populate_links)
+{
+ struct bpf_program *prog;
+ int i;
+
+ if (!prog_cnt)
+ return;
+
+ codegen("\
+ \n\
+ \n\
+ /* programs */ \n\
+ s->prog_cnt = %zu; \n\
+ s->prog_skel_sz = sizeof(*s->progs); \n\
+ s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
+ if (!s->progs) \n\
+ goto err; \n\
+ ",
+ prog_cnt
+ );
+ i = 0;
+ bpf_object__for_each_program(prog, obj) {
+ codegen("\
+ \n\
+ \n\
+ s->progs[%1$zu].name = \"%2$s\"; \n\
+ s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
+ ",
+ i, bpf_program__name(prog));
+
+ if (populate_links) {
+ codegen("\
+ \n\
+ s->progs[%1$zu].link = &obj->links.%2$s;\n\
+ ",
+ i, bpf_program__name(prog));
+ }
+ i++;
+ }
+}
+
static int do_skeleton(int argc, char **argv)
{
char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
- size_t i, map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
+ size_t map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
struct bpf_object *obj = NULL;
prog_cnt++;
}
- get_header_guard(header_guard, obj_name);
+ get_header_guard(header_guard, obj_name, "SKEL_H");
if (use_loader) {
codegen("\
\n\
",
obj_name
);
- if (map_cnt) {
- codegen("\
- \n\
- \n\
- /* maps */ \n\
- s->map_cnt = %zu; \n\
- s->map_skel_sz = sizeof(*s->maps); \n\
- s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
- if (!s->maps) \n\
- goto err; \n\
- ",
- map_cnt
- );
- i = 0;
- bpf_object__for_each_map(map, obj) {
- if (!get_map_ident(map, ident, sizeof(ident)))
- continue;
- codegen("\
- \n\
- \n\
- s->maps[%zu].name = \"%s\"; \n\
- s->maps[%zu].map = &obj->maps.%s; \n\
- ",
- i, bpf_map__name(map), i, ident);
- /* memory-mapped internal maps */
- if (bpf_map__is_internal(map) &&
- (bpf_map__map_flags(map) & BPF_F_MMAPABLE)) {
- printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
- i, ident);
- }
- i++;
- }
- }
- if (prog_cnt) {
- codegen("\
- \n\
- \n\
- /* programs */ \n\
- s->prog_cnt = %zu; \n\
- s->prog_skel_sz = sizeof(*s->progs); \n\
- s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
- if (!s->progs) \n\
- goto err; \n\
- ",
- prog_cnt
- );
- i = 0;
- bpf_object__for_each_program(prog, obj) {
- codegen("\
- \n\
- \n\
- s->progs[%1$zu].name = \"%2$s\"; \n\
- s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
- s->progs[%1$zu].link = &obj->links.%2$s;\n\
- ",
- i, bpf_program__name(prog));
- i++;
- }
- }
+ codegen_maps_skeleton(obj, map_cnt, true /*mmaped*/);
+ codegen_progs_skeleton(obj, prog_cnt, true /*populate_links*/);
+
codegen("\
\n\
\n\
return err;
}
+/* Subskeletons are like skeletons, except they don't own the bpf_object,
+ * associated maps, links, etc. Instead, they know about the existence of
+ * variables, maps, programs and are able to find their locations
+ * _at runtime_ from an already loaded bpf_object.
+ *
+ * This allows for library-like BPF objects to have userspace counterparts
+ * with access to their own items without having to know anything about the
+ * final BPF object that the library was linked into.
+ */
+static int do_subskeleton(int argc, char **argv)
+{
+ char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SUBSKEL_H__")];
+ size_t i, len, file_sz, map_cnt = 0, prog_cnt = 0, mmap_sz, var_cnt = 0, var_idx = 0;
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+ char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
+ struct bpf_object *obj = NULL;
+ const char *file, *var_name;
+ char ident[256];
+ int fd, err = -1, map_type_id;
+ const struct bpf_map *map;
+ struct bpf_program *prog;
+ struct btf *btf;
+ const struct btf_type *map_type, *var_type;
+ const struct btf_var_secinfo *var;
+ struct stat st;
+
+ if (!REQ_ARGS(1)) {
+ usage();
+ return -1;
+ }
+ file = GET_ARG();
+
+ while (argc) {
+ if (!REQ_ARGS(2))
+ return -1;
+
+ if (is_prefix(*argv, "name")) {
+ NEXT_ARG();
+
+ if (obj_name[0] != '\0') {
+ p_err("object name already specified");
+ return -1;
+ }
+
+ strncpy(obj_name, *argv, MAX_OBJ_NAME_LEN - 1);
+ obj_name[MAX_OBJ_NAME_LEN - 1] = '\0';
+ } else {
+ p_err("unknown arg %s", *argv);
+ return -1;
+ }
+
+ NEXT_ARG();
+ }
+
+ if (argc) {
+ p_err("extra unknown arguments");
+ return -1;
+ }
+
+ if (use_loader) {
+ p_err("cannot use loader for subskeletons");
+ return -1;
+ }
+
+ if (stat(file, &st)) {
+ p_err("failed to stat() %s: %s", file, strerror(errno));
+ return -1;
+ }
+ file_sz = st.st_size;
+ mmap_sz = roundup(file_sz, sysconf(_SC_PAGE_SIZE));
+ fd = open(file, O_RDONLY);
+ if (fd < 0) {
+ p_err("failed to open() %s: %s", file, strerror(errno));
+ return -1;
+ }
+ obj_data = mmap(NULL, mmap_sz, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (obj_data == MAP_FAILED) {
+ obj_data = NULL;
+ p_err("failed to mmap() %s: %s", file, strerror(errno));
+ goto out;
+ }
+ if (obj_name[0] == '\0')
+ get_obj_name(obj_name, file);
+
+ /* The empty object name allows us to use bpf_map__name and produce
+ * ELF section names out of it. (".data" instead of "obj.data")
+ */
+ opts.object_name = "";
+ obj = bpf_object__open_mem(obj_data, file_sz, &opts);
+ if (!obj) {
+ char err_buf[256];
+
+ libbpf_strerror(errno, err_buf, sizeof(err_buf));
+ p_err("failed to open BPF object file: %s", err_buf);
+ obj = NULL;
+ goto out;
+ }
+
+ btf = bpf_object__btf(obj);
+ if (!btf) {
+ err = -1;
+ p_err("need btf type information for %s", obj_name);
+ goto out;
+ }
+
+ bpf_object__for_each_program(prog, obj) {
+ prog_cnt++;
+ }
+
+ /* First, count how many variables we have to find.
+ * We need this in advance so the subskel can allocate the right
+ * amount of storage.
+ */
+ bpf_object__for_each_map(map, obj) {
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+
+ /* Also count all maps that have a name */
+ map_cnt++;
+
+ if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ continue;
+
+ map_type_id = bpf_map__btf_value_type_id(map);
+ if (map_type_id <= 0) {
+ err = map_type_id;
+ goto out;
+ }
+ map_type = btf__type_by_id(btf, map_type_id);
+
+ var = btf_var_secinfos(map_type);
+ len = btf_vlen(map_type);
+ for (i = 0; i < len; i++, var++) {
+ var_type = btf__type_by_id(btf, var->type);
+
+ if (btf_var(var_type)->linkage == BTF_VAR_STATIC)
+ continue;
+
+ var_cnt++;
+ }
+ }
+
+ get_header_guard(header_guard, obj_name, "SUBSKEL_H");
+ codegen("\
+ \n\
+ /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ \n\
+ \n\
+ /* THIS FILE IS AUTOGENERATED! */ \n\
+ #ifndef %2$s \n\
+ #define %2$s \n\
+ \n\
+ #include <errno.h> \n\
+ #include <stdlib.h> \n\
+ #include <bpf/libbpf.h> \n\
+ \n\
+ struct %1$s { \n\
+ struct bpf_object *obj; \n\
+ struct bpf_object_subskeleton *subskel; \n\
+ ", obj_name, header_guard);
+
+ if (map_cnt) {
+ printf("\tstruct {\n");
+ bpf_object__for_each_map(map, obj) {
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+ printf("\t\tstruct bpf_map *%s;\n", ident);
+ }
+ printf("\t} maps;\n");
+ }
+
+ if (prog_cnt) {
+ printf("\tstruct {\n");
+ bpf_object__for_each_program(prog, obj) {
+ printf("\t\tstruct bpf_program *%s;\n",
+ bpf_program__name(prog));
+ }
+ printf("\t} progs;\n");
+ }
+
+ err = codegen_subskel_datasecs(obj, obj_name);
+ if (err)
+ goto out;
+
+ /* emit code that will allocate enough storage for all symbols */
+ codegen("\
+ \n\
+ \n\
+ #ifdef __cplusplus \n\
+ static inline struct %1$s *open(const struct bpf_object *src);\n\
+ static inline void destroy(struct %1$s *skel); \n\
+ #endif /* __cplusplus */ \n\
+ }; \n\
+ \n\
+ static inline void \n\
+ %1$s__destroy(struct %1$s *skel) \n\
+ { \n\
+ if (!skel) \n\
+ return; \n\
+ if (skel->subskel) \n\
+ bpf_object__destroy_subskeleton(skel->subskel);\n\
+ free(skel); \n\
+ } \n\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open(const struct bpf_object *src) \n\
+ { \n\
+ struct %1$s *obj; \n\
+ struct bpf_object_subskeleton *s; \n\
+ int err; \n\
+ \n\
+ obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
+ if (!obj) { \n\
+ errno = ENOMEM; \n\
+ goto err; \n\
+ } \n\
+ s = (struct bpf_object_subskeleton *)calloc(1, sizeof(*s));\n\
+ if (!s) { \n\
+ errno = ENOMEM; \n\
+ goto err; \n\
+ } \n\
+ s->sz = sizeof(*s); \n\
+ s->obj = src; \n\
+ s->var_skel_sz = sizeof(*s->vars); \n\
+ obj->subskel = s; \n\
+ \n\
+ /* vars */ \n\
+ s->var_cnt = %2$d; \n\
+ s->vars = (struct bpf_var_skeleton *)calloc(%2$d, sizeof(*s->vars));\n\
+ if (!s->vars) { \n\
+ errno = ENOMEM; \n\
+ goto err; \n\
+ } \n\
+ ",
+ obj_name, var_cnt
+ );
+
+ /* walk through each symbol and emit the runtime representation */
+ bpf_object__for_each_map(map, obj) {
+ if (!is_internal_mmapable_map(map, ident, sizeof(ident)))
+ continue;
+
+ map_type_id = bpf_map__btf_value_type_id(map);
+ if (map_type_id <= 0)
+ /* skip over internal maps with no type*/
+ continue;
+
+ map_type = btf__type_by_id(btf, map_type_id);
+ var = btf_var_secinfos(map_type);
+ len = btf_vlen(map_type);
+ for (i = 0; i < len; i++, var++) {
+ var_type = btf__type_by_id(btf, var->type);
+ var_name = btf__name_by_offset(btf, var_type->name_off);
+
+ if (btf_var(var_type)->linkage == BTF_VAR_STATIC)
+ continue;
+
+ /* Note that we use the dot prefix in .data as the
+ * field access operator i.e. maps%s becomes maps.data
+ */
+ codegen("\
+ \n\
+ \n\
+ s->vars[%3$d].name = \"%1$s\"; \n\
+ s->vars[%3$d].map = &obj->maps.%2$s; \n\
+ s->vars[%3$d].addr = (void **) &obj->%2$s.%1$s;\n\
+ ", var_name, ident, var_idx);
+
+ var_idx++;
+ }
+ }
+
+ codegen_maps_skeleton(obj, map_cnt, false /*mmaped*/);
+ codegen_progs_skeleton(obj, prog_cnt, false /*links*/);
+
+ codegen("\
+ \n\
+ \n\
+ err = bpf_object__open_subskeleton(s); \n\
+ if (err) \n\
+ goto err; \n\
+ \n\
+ return obj; \n\
+ err: \n\
+ %1$s__destroy(obj); \n\
+ errno = -err; \n\
+ return NULL; \n\
+ } \n\
+ \n\
+ #ifdef __cplusplus \n\
+ struct %1$s *%1$s::open(const struct bpf_object *src) { return %1$s__open(src); }\n\
+ void %1$s::destroy(struct %1$s *skel) { %1$s__destroy(skel); }\n\
+ #endif /* __cplusplus */ \n\
+ \n\
+ #endif /* %2$s */ \n\
+ ",
+ obj_name, header_guard);
+ err = 0;
+out:
+ bpf_object__close(obj);
+ if (obj_data)
+ munmap(obj_data, mmap_sz);
+ close(fd);
+ return err;
+}
+
static int do_object(int argc, char **argv)
{
struct bpf_linker *linker;
fprintf(stderr,
"Usage: %1$s %2$s object OUTPUT_FILE INPUT_FILE [INPUT_FILE...]\n"
" %1$s %2$s skeleton FILE [name OBJECT_NAME]\n"
+ " %1$s %2$s subskeleton FILE [name OBJECT_NAME]\n"
" %1$s %2$s min_core_btf INPUT OUTPUT OBJECT [OBJECT...]\n"
" %1$s %2$s help\n"
"\n"
static const struct cmd cmds[] = {
{ "object", do_object },
{ "skeleton", do_skeleton },
+ { "subskeleton", do_subskeleton },
{ "min_core_btf", do_min_core_btf},
{ "help", do_help },
{ 0 }
projects / platform / kernel / linux-rpi.git / commitdiff