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-rw-r--r--tools/bpf/bpftool/gen.c621
1 files changed, 621 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
new file mode 100644
index 000000000..4033c46d8
--- /dev/null
+++ b/tools/bpf/bpftool/gen.c
@@ -0,0 +1,621 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2019 Facebook */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <bpf/btf.h>
+
+#include "json_writer.h"
+#include "main.h"
+
+#define MAX_OBJ_NAME_LEN 64
+
+static void sanitize_identifier(char *name)
+{
+ int i;
+
+ for (i = 0; name[i]; i++)
+ if (!isalnum(name[i]) && name[i] != '_')
+ name[i] = '_';
+}
+
+static bool str_has_suffix(const char *str, const char *suffix)
+{
+ size_t i, n1 = strlen(str), n2 = strlen(suffix);
+
+ if (n1 < n2)
+ return false;
+
+ for (i = 0; i < n2; i++) {
+ if (str[n1 - i - 1] != suffix[n2 - i - 1])
+ return false;
+ }
+
+ return true;
+}
+
+static void get_obj_name(char *name, const char *file)
+{
+ /* Using basename() GNU version which doesn't modify arg. */
+ strncpy(name, basename(file), MAX_OBJ_NAME_LEN - 1);
+ name[MAX_OBJ_NAME_LEN - 1] = '\0';
+ if (str_has_suffix(name, ".o"))
+ name[strlen(name) - 2] = '\0';
+ sanitize_identifier(name);
+}
+
+static void get_header_guard(char *guard, const char *obj_name)
+{
+ int i;
+
+ sprintf(guard, "__%s_SKEL_H__", obj_name);
+ for (i = 0; guard[i]; i++)
+ guard[i] = toupper(guard[i]);
+}
+
+static const char *get_map_ident(const struct bpf_map *map)
+{
+ const char *name = bpf_map__name(map);
+
+ if (!bpf_map__is_internal(map))
+ return name;
+
+ if (str_has_suffix(name, ".data"))
+ return "data";
+ else if (str_has_suffix(name, ".rodata"))
+ return "rodata";
+ else if (str_has_suffix(name, ".bss"))
+ return "bss";
+ else if (str_has_suffix(name, ".kconfig"))
+ return "kconfig";
+ else
+ return NULL;
+}
+
+static void codegen_btf_dump_printf(void *ctx, const char *fmt, va_list args)
+{
+ vprintf(fmt, args);
+}
+
+static int codegen_datasec_def(struct bpf_object *obj,
+ struct btf *btf,
+ struct btf_dump *d,
+ const struct btf_type *sec,
+ const char *obj_name)
+{
+ const char *sec_name = btf__name_by_offset(btf, sec->name_off);
+ const struct btf_var_secinfo *sec_var = btf_var_secinfos(sec);
+ int i, err, off = 0, pad_cnt = 0, vlen = btf_vlen(sec);
+ const char *sec_ident;
+ char var_ident[256];
+ bool strip_mods = false;
+
+ if (strcmp(sec_name, ".data") == 0) {
+ sec_ident = "data";
+ } else if (strcmp(sec_name, ".bss") == 0) {
+ sec_ident = "bss";
+ } else if (strcmp(sec_name, ".rodata") == 0) {
+ sec_ident = "rodata";
+ strip_mods = true;
+ } else if (strcmp(sec_name, ".kconfig") == 0) {
+ sec_ident = "kconfig";
+ } else {
+ return 0;
+ }
+
+ printf(" struct %s__%s {\n", obj_name, sec_ident);
+ for (i = 0; i < vlen; i++, sec_var++) {
+ const struct btf_type *var = btf__type_by_id(btf, sec_var->type);
+ const char *var_name = btf__name_by_offset(btf, var->name_off);
+ DECLARE_LIBBPF_OPTS(btf_dump_emit_type_decl_opts, opts,
+ .field_name = var_ident,
+ .indent_level = 2,
+ .strip_mods = strip_mods,
+ );
+ int need_off = sec_var->offset, align_off, align;
+ __u32 var_type_id = var->type;
+
+ if (off > need_off) {
+ p_err("Something is wrong for %s's variable #%d: need offset %d, already at %d.\n",
+ sec_name, i, need_off, off);
+ return -EINVAL;
+ }
+
+ align = btf__align_of(btf, var->type);
+ if (align <= 0) {
+ p_err("Failed to determine alignment of variable '%s': %d",
+ var_name, align);
+ return -EINVAL;
+ }
+ /* Assume 32-bit architectures when generating data section
+ * struct memory layout. Given bpftool can't know which target
+ * host architecture it's emitting skeleton for, we need to be
+ * conservative and assume 32-bit one to ensure enough padding
+ * bytes are generated for pointer and long types. This will
+ * still work correctly for 64-bit architectures, because in
+ * the worst case we'll generate unnecessary padding field,
+ * which on 64-bit architectures is not strictly necessary and
+ * would be handled by natural 8-byte alignment. But it still
+ * will be a correct memory layout, based on recorded offsets
+ * in BTF.
+ */
+ if (align > 4)
+ align = 4;
+
+ align_off = (off + align - 1) / align * align;
+ if (align_off != need_off) {
+ printf("\t\tchar __pad%d[%d];\n",
+ pad_cnt, need_off - off);
+ pad_cnt++;
+ }
+
+ /* sanitize variable name, e.g., for static vars inside
+ * a function, it's name is '<function name>.<variable name>',
+ * which we'll turn into a '<function name>_<variable name>'
+ */
+ var_ident[0] = '\0';
+ strncat(var_ident, var_name, sizeof(var_ident) - 1);
+ sanitize_identifier(var_ident);
+
+ printf("\t\t");
+ err = btf_dump__emit_type_decl(d, var_type_id, &opts);
+ if (err)
+ return err;
+ printf(";\n");
+
+ off = sec_var->offset + sec_var->size;
+ }
+ printf(" } *%s;\n", sec_ident);
+ return 0;
+}
+
+static int codegen_datasecs(struct bpf_object *obj, const char *obj_name)
+{
+ struct btf *btf = bpf_object__btf(obj);
+ int n = btf__get_nr_types(btf);
+ struct btf_dump *d;
+ int i, err = 0;
+
+ d = btf_dump__new(btf, NULL, NULL, codegen_btf_dump_printf);
+ if (IS_ERR(d))
+ return PTR_ERR(d);
+
+ for (i = 1; i <= n; i++) {
+ const struct btf_type *t = btf__type_by_id(btf, i);
+
+ if (!btf_is_datasec(t))
+ continue;
+
+ err = codegen_datasec_def(obj, btf, d, t, obj_name);
+ if (err)
+ goto out;
+ }
+out:
+ btf_dump__free(d);
+ return err;
+}
+
+static void codegen(const char *template, ...)
+{
+ const char *src, *end;
+ int skip_tabs = 0, n;
+ char *s, *dst;
+ va_list args;
+ char c;
+
+ n = strlen(template);
+ s = malloc(n + 1);
+ if (!s)
+ exit(-1);
+ src = template;
+ dst = s;
+
+ /* find out "baseline" indentation to skip */
+ while ((c = *src++)) {
+ if (c == '\t') {
+ skip_tabs++;
+ } else if (c == '\n') {
+ break;
+ } else {
+ p_err("unrecognized character at pos %td in template '%s'",
+ src - template - 1, template);
+ free(s);
+ exit(-1);
+ }
+ }
+
+ while (*src) {
+ /* skip baseline indentation tabs */
+ for (n = skip_tabs; n > 0; n--, src++) {
+ if (*src != '\t') {
+ p_err("not enough tabs at pos %td in template '%s'",
+ src - template - 1, template);
+ free(s);
+ exit(-1);
+ }
+ }
+ /* trim trailing whitespace */
+ end = strchrnul(src, '\n');
+ for (n = end - src; n > 0 && isspace(src[n - 1]); n--)
+ ;
+ memcpy(dst, src, n);
+ dst += n;
+ if (*end)
+ *dst++ = '\n';
+ src = *end ? end + 1 : end;
+ }
+ *dst++ = '\0';
+
+ /* print out using adjusted template */
+ va_start(args, template);
+ n = vprintf(s, args);
+ va_end(args);
+
+ free(s);
+}
+
+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;
+ 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, *ident;
+ struct bpf_program *prog;
+ int fd, len, err = -1;
+ struct bpf_map *map;
+ struct btf *btf;
+ struct stat st;
+
+ if (!REQ_ARGS(1)) {
+ usage();
+ return -1;
+ }
+ file = GET_ARG();
+
+ if (argc) {
+ p_err("extra unknown arguments");
+ 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;
+ }
+ get_obj_name(obj_name, file);
+ opts.object_name = obj_name;
+ obj = bpf_object__open_mem(obj_data, file_sz, &opts);
+ if (IS_ERR(obj)) {
+ char err_buf[256];
+
+ libbpf_strerror(PTR_ERR(obj), err_buf, sizeof(err_buf));
+ p_err("failed to open BPF object file: %s", err_buf);
+ obj = NULL;
+ goto out;
+ }
+
+ bpf_object__for_each_map(map, obj) {
+ ident = get_map_ident(map);
+ if (!ident) {
+ p_err("ignoring unrecognized internal map '%s'...",
+ bpf_map__name(map));
+ continue;
+ }
+ map_cnt++;
+ }
+ bpf_object__for_each_program(prog, obj) {
+ prog_cnt++;
+ }
+
+ get_header_guard(header_guard, obj_name);
+ 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 <stdlib.h> \n\
+ #include <bpf/libbpf.h> \n\
+ \n\
+ struct %1$s { \n\
+ struct bpf_object_skeleton *skeleton; \n\
+ struct bpf_object *obj; \n\
+ ",
+ obj_name, header_guard
+ );
+
+ if (map_cnt) {
+ printf("\tstruct {\n");
+ bpf_object__for_each_map(map, obj) {
+ ident = get_map_ident(map);
+ if (!ident)
+ continue;
+ printf("\t\tstruct bpf_map *%s;\n", ident);
+ }
+ printf("\t} maps;\n");
+ }
+
+ if (prog_cnt) {
+ printf("\tstruct {\n");
+ bpf_object__for_each_program(prog, obj) {
+ printf("\t\tstruct bpf_program *%s;\n",
+ bpf_program__name(prog));
+ }
+ printf("\t} progs;\n");
+ printf("\tstruct {\n");
+ bpf_object__for_each_program(prog, obj) {
+ printf("\t\tstruct bpf_link *%s;\n",
+ bpf_program__name(prog));
+ }
+ printf("\t} links;\n");
+ }
+
+ btf = bpf_object__btf(obj);
+ if (btf) {
+ err = codegen_datasecs(obj, obj_name);
+ if (err)
+ goto out;
+ }
+
+ codegen("\
+ \n\
+ }; \n\
+ \n\
+ static void \n\
+ %1$s__destroy(struct %1$s *obj) \n\
+ { \n\
+ if (!obj) \n\
+ return; \n\
+ if (obj->skeleton) \n\
+ bpf_object__destroy_skeleton(obj->skeleton);\n\
+ free(obj); \n\
+ } \n\
+ \n\
+ static inline int \n\
+ %1$s__create_skeleton(struct %1$s *obj); \n\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open_opts(const struct bpf_object_open_opts *opts) \n\
+ { \n\
+ struct %1$s *obj; \n\
+ \n\
+ obj = (struct %1$s *)calloc(1, sizeof(*obj)); \n\
+ if (!obj) \n\
+ return NULL; \n\
+ if (%1$s__create_skeleton(obj)) \n\
+ goto err; \n\
+ if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
+ goto err; \n\
+ \n\
+ return obj; \n\
+ err: \n\
+ %1$s__destroy(obj); \n\
+ return NULL; \n\
+ } \n\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open(void) \n\
+ { \n\
+ return %1$s__open_opts(NULL); \n\
+ } \n\
+ \n\
+ static inline int \n\
+ %1$s__load(struct %1$s *obj) \n\
+ { \n\
+ return bpf_object__load_skeleton(obj->skeleton); \n\
+ } \n\
+ \n\
+ static inline struct %1$s * \n\
+ %1$s__open_and_load(void) \n\
+ { \n\
+ struct %1$s *obj; \n\
+ \n\
+ obj = %1$s__open(); \n\
+ if (!obj) \n\
+ return NULL; \n\
+ if (%1$s__load(obj)) { \n\
+ %1$s__destroy(obj); \n\
+ return NULL; \n\
+ } \n\
+ return obj; \n\
+ } \n\
+ \n\
+ static inline int \n\
+ %1$s__attach(struct %1$s *obj) \n\
+ { \n\
+ return bpf_object__attach_skeleton(obj->skeleton); \n\
+ } \n\
+ \n\
+ static inline void \n\
+ %1$s__detach(struct %1$s *obj) \n\
+ { \n\
+ return bpf_object__detach_skeleton(obj->skeleton); \n\
+ } \n\
+ ",
+ obj_name
+ );
+
+ codegen("\
+ \n\
+ \n\
+ static inline int \n\
+ %1$s__create_skeleton(struct %1$s *obj) \n\
+ { \n\
+ struct bpf_object_skeleton *s; \n\
+ \n\
+ s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
+ if (!s) \n\
+ return -1; \n\
+ obj->skeleton = s; \n\
+ \n\
+ s->sz = sizeof(*s); \n\
+ s->name = \"%1$s\"; \n\
+ s->obj = &obj->obj; \n\
+ ",
+ obj_name
+ );
+ if (map_cnt) {
+ codegen("\
+ \n\
+ \n\
+ /* maps */ \n\
+ s->map_cnt = %zu; \n\
+ s->map_skel_sz = sizeof(*s->maps); \n\
+ s->maps = (struct bpf_map_skeleton *)calloc(s->map_cnt, s->map_skel_sz);\n\
+ if (!s->maps) \n\
+ goto err; \n\
+ ",
+ map_cnt
+ );
+ i = 0;
+ bpf_object__for_each_map(map, obj) {
+ ident = get_map_ident(map);
+
+ if (!ident)
+ continue;
+
+ codegen("\
+ \n\
+ \n\
+ s->maps[%zu].name = \"%s\"; \n\
+ s->maps[%zu].map = &obj->maps.%s; \n\
+ ",
+ i, bpf_map__name(map), i, ident);
+ /* memory-mapped internal maps */
+ if (bpf_map__is_internal(map) &&
+ (bpf_map__def(map)->map_flags & BPF_F_MMAPABLE)) {
+ printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
+ i, ident);
+ }
+ i++;
+ }
+ }
+ if (prog_cnt) {
+ codegen("\
+ \n\
+ \n\
+ /* programs */ \n\
+ s->prog_cnt = %zu; \n\
+ s->prog_skel_sz = sizeof(*s->progs); \n\
+ s->progs = (struct bpf_prog_skeleton *)calloc(s->prog_cnt, s->prog_skel_sz);\n\
+ if (!s->progs) \n\
+ goto err; \n\
+ ",
+ prog_cnt
+ );
+ i = 0;
+ bpf_object__for_each_program(prog, obj) {
+ codegen("\
+ \n\
+ \n\
+ s->progs[%1$zu].name = \"%2$s\"; \n\
+ s->progs[%1$zu].prog = &obj->progs.%2$s;\n\
+ s->progs[%1$zu].link = &obj->links.%2$s;\n\
+ ",
+ i, bpf_program__name(prog));
+ i++;
+ }
+ }
+ codegen("\
+ \n\
+ \n\
+ s->data_sz = %d; \n\
+ s->data = (void *)\"\\ \n\
+ ",
+ file_sz);
+
+ /* embed contents of BPF object file */
+ for (i = 0, len = 0; i < file_sz; i++) {
+ int w = obj_data[i] ? 4 : 2;
+
+ len += w;
+ if (len > 78) {
+ printf("\\\n");
+ len = w;
+ }
+ if (!obj_data[i])
+ printf("\\0");
+ else
+ printf("\\x%02x", (unsigned char)obj_data[i]);
+ }
+
+ codegen("\
+ \n\
+ \"; \n\
+ \n\
+ return 0; \n\
+ err: \n\
+ bpf_object__destroy_skeleton(s); \n\
+ return -1; \n\
+ } \n\
+ \n\
+ #endif /* %s */ \n\
+ ",
+ header_guard);
+ err = 0;
+out:
+ bpf_object__close(obj);
+ if (obj_data)
+ munmap(obj_data, mmap_sz);
+ close(fd);
+ return err;
+}
+
+static int do_help(int argc, char **argv)
+{
+ if (json_output) {
+ jsonw_null(json_wtr);
+ return 0;
+ }
+
+ fprintf(stderr,
+ "Usage: %1$s %2$s skeleton FILE\n"
+ " %1$s %2$s help\n"
+ "\n"
+ " " HELP_SPEC_OPTIONS "\n"
+ "",
+ bin_name, "gen");
+
+ return 0;
+}
+
+static const struct cmd cmds[] = {
+ { "skeleton", do_skeleton },
+ { "help", do_help },
+ { 0 }
+};
+
+int do_gen(int argc, char **argv)
+{
+ return cmd_select(cmds, argc, argv, do_help);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-30 03:35:30 +0000