1 files changed, 432 insertions, 12 deletions

diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c
index 1b8ec91899e6..b3745ed711ba 100644
--- a/tools/bpf/bpftool/btf.c
+++ b/tools/bpf/bpftool/btf.c
@@ -8,11 +8,15 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
-#include <bpf.h>
-#include <libbpf.h>
+#include <bpf/bpf.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
 #include <linux/btf.h>
+#include <linux/hashtable.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
 
-#include "btf.h"
 #include "json_writer.h"
 #include "main.h"
 
@@ -35,6 +39,16 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = {
 	[BTF_KIND_DATASEC]	= "DATASEC",
 };
 
+struct btf_attach_table {
+	DECLARE_HASHTABLE(table, 16);
+};
+
+struct btf_attach_point {
+	__u32 obj_id;
+	__u32 btf_id;
+	struct hlist_node hash;
+};
+
 static const char *btf_int_enc_str(__u8 encoding)
 {
 	switch (encoding) {
@@ -63,6 +77,20 @@ static const char *btf_var_linkage_str(__u32 linkage)
 	}
 }
 
+static const char *btf_func_linkage_str(const struct btf_type *t)
+{
+	switch (btf_vlen(t)) {
+	case BTF_FUNC_STATIC:
+		return "static";
+	case BTF_FUNC_GLOBAL:
+		return "global";
+	case BTF_FUNC_EXTERN:
+		return "extern";
+	default:
+		return "(unknown)";
+	}
+}
+
 static const char *btf_str(const struct btf *btf, __u32 off)
 {
 	if (!off)
@@ -217,12 +245,17 @@ static int dump_btf_type(const struct btf *btf, __u32 id,
 			printf(" fwd_kind=%s", fwd_kind);
 		break;
 	}
-	case BTF_KIND_FUNC:
-		if (json_output)
+	case BTF_KIND_FUNC: {
+		const char *linkage = btf_func_linkage_str(t);
+
+		if (json_output) {
 			jsonw_uint_field(w, "type_id", t->type);
-		else
-			printf(" type_id=%u", t->type);
+			jsonw_string_field(w, "linkage", linkage);
+		} else {
+			printf(" type_id=%u linkage=%s", t->type, linkage);
+		}
 		break;
+	}
 	case BTF_KIND_FUNC_PROTO: {
 		const struct btf_param *p = (const void *)(t + 1);
 		__u16 vlen = BTF_INFO_VLEN(t->info);
@@ -356,6 +389,10 @@ static int dump_btf_c(const struct btf *btf,
 	if (IS_ERR(d))
 		return PTR_ERR(d);
 
+	printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
+	printf("#pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)\n");
+	printf("#endif\n\n");
+
 	if (root_type_cnt) {
 		for (i = 0; i < root_type_cnt; i++) {
 			err = btf_dump__dump_type(d, root_type_ids[i]);
@@ -372,11 +409,63 @@ static int dump_btf_c(const struct btf *btf,
 		}
 	}
 
+	printf("#ifndef BPF_NO_PRESERVE_ACCESS_INDEX\n");
+	printf("#pragma clang attribute pop\n");
+	printf("#endif\n");
+
 done:
 	btf_dump__free(d);
 	return err;
 }
 
+static struct btf *btf__parse_raw(const char *file)
+{
+	struct btf *btf;
+	struct stat st;
+	__u8 *buf;
+	FILE *f;
+
+	if (stat(file, &st))
+		return NULL;
+
+	f = fopen(file, "rb");
+	if (!f)
+		return NULL;
+
+	buf = malloc(st.st_size);
+	if (!buf) {
+		btf = ERR_PTR(-ENOMEM);
+		goto exit_close;
+	}
+
+	if ((size_t) st.st_size != fread(buf, 1, st.st_size, f)) {
+		btf = ERR_PTR(-EINVAL);
+		goto exit_free;
+	}
+
+	btf = btf__new(buf, st.st_size);
+
+exit_free:
+	free(buf);
+exit_close:
+	fclose(f);
+	return btf;
+}
+
+static bool is_btf_raw(const char *file)
+{
+	__u16 magic = 0;
+	int fd, nb_read;
+
+	fd = open(file, O_RDONLY);
+	if (fd < 0)
+		return false;
+
+	nb_read = read(fd, &magic, sizeof(magic));
+	close(fd);
+	return nb_read == sizeof(magic) && magic == BTF_MAGIC;
+}
+
 static int do_dump(int argc, char **argv)
 {
 	struct btf *btf = NULL;
@@ -449,16 +538,20 @@ static int do_dump(int argc, char **argv)
 
 		btf_id = strtoul(*argv, &endptr, 0);
 		if (*endptr) {
-			p_err("can't parse %s as ID", **argv);
+			p_err("can't parse %s as ID", *argv);
 			return -1;
 		}
 		NEXT_ARG();
 	} else if (is_prefix(src, "file")) {
-		btf = btf__parse_elf(*argv, NULL);
+		if (is_btf_raw(*argv))
+			btf = btf__parse_raw(*argv);
+		else
+			btf = btf__parse_elf(*argv, NULL);
+
 		if (IS_ERR(btf)) {
 			err = PTR_ERR(btf);
 			btf = NULL;
-			p_err("failed to load BTF from %s: %s", 
+			p_err("failed to load BTF from %s: %s",
 			      *argv, strerror(err));
 			goto done;
 		}
@@ -522,6 +615,330 @@ done:
 	return err;
 }
 
+static int btf_parse_fd(int *argc, char ***argv)
+{
+	unsigned int id;
+	char *endptr;
+	int fd;
+
+	if (!is_prefix(*argv[0], "id")) {
+		p_err("expected 'id', got: '%s'?", **argv);
+		return -1;
+	}
+	NEXT_ARGP();
+
+	id = strtoul(**argv, &endptr, 0);
+	if (*endptr) {
+		p_err("can't parse %s as ID", **argv);
+		return -1;
+	}
+	NEXT_ARGP();
+
+	fd = bpf_btf_get_fd_by_id(id);
+	if (fd < 0)
+		p_err("can't get BTF object by id (%u): %s",
+		      id, strerror(errno));
+
+	return fd;
+}
+
+static void delete_btf_table(struct btf_attach_table *tab)
+{
+	struct btf_attach_point *obj;
+	struct hlist_node *tmp;
+
+	unsigned int bkt;
+
+	hash_for_each_safe(tab->table, bkt, tmp, obj, hash) {
+		hash_del(&obj->hash);
+		free(obj);
+	}
+}
+
+static int
+build_btf_type_table(struct btf_attach_table *tab, enum bpf_obj_type type,
+		     void *info, __u32 *len)
+{
+	static const char * const names[] = {
+		[BPF_OBJ_UNKNOWN]	= "unknown",
+		[BPF_OBJ_PROG]		= "prog",
+		[BPF_OBJ_MAP]		= "map",
+	};
+	struct btf_attach_point *obj_node;
+	__u32 btf_id, id = 0;
+	int err;
+	int fd;
+
+	while (true) {
+		switch (type) {
+		case BPF_OBJ_PROG:
+			err = bpf_prog_get_next_id(id, &id);
+			break;
+		case BPF_OBJ_MAP:
+			err = bpf_map_get_next_id(id, &id);
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (err) {
+			if (errno == ENOENT) {
+				err = 0;
+				break;
+			}
+			p_err("can't get next %s: %s%s", names[type],
+			      strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
+			goto err_free;
+		}
+
+		switch (type) {
+		case BPF_OBJ_PROG:
+			fd = bpf_prog_get_fd_by_id(id);
+			break;
+		case BPF_OBJ_MAP:
+			fd = bpf_map_get_fd_by_id(id);
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			p_err("can't get %s by id (%u): %s", names[type], id,
+			      strerror(errno));
+			err = -1;
+			goto err_free;
+		}
+
+		memset(info, 0, *len);
+		err = bpf_obj_get_info_by_fd(fd, info, len);
+		close(fd);
+		if (err) {
+			p_err("can't get %s info: %s", names[type],
+			      strerror(errno));
+			goto err_free;
+		}
+
+		switch (type) {
+		case BPF_OBJ_PROG:
+			btf_id = ((struct bpf_prog_info *)info)->btf_id;
+			break;
+		case BPF_OBJ_MAP:
+			btf_id = ((struct bpf_map_info *)info)->btf_id;
+			break;
+		default:
+			err = -1;
+			p_err("unexpected object type: %d", type);
+			goto err_free;
+		}
+		if (!btf_id)
+			continue;
+
+		obj_node = calloc(1, sizeof(*obj_node));
+		if (!obj_node) {
+			p_err("failed to allocate memory: %s", strerror(errno));
+			goto err_free;
+		}
+
+		obj_node->obj_id = id;
+		obj_node->btf_id = btf_id;
+		hash_add(tab->table, &obj_node->hash, obj_node->btf_id);
+	}
+
+	return 0;
+
+err_free:
+	delete_btf_table(tab);
+	return err;
+}
+
+static int
+build_btf_tables(struct btf_attach_table *btf_prog_table,
+		 struct btf_attach_table *btf_map_table)
+{
+	struct bpf_prog_info prog_info;
+	__u32 prog_len = sizeof(prog_info);
+	struct bpf_map_info map_info;
+	__u32 map_len = sizeof(map_info);
+	int err = 0;
+
+	err = build_btf_type_table(btf_prog_table, BPF_OBJ_PROG, &prog_info,
+				   &prog_len);
+	if (err)
+		return err;
+
+	err = build_btf_type_table(btf_map_table, BPF_OBJ_MAP, &map_info,
+				   &map_len);
+	if (err) {
+		delete_btf_table(btf_prog_table);
+		return err;
+	}
+
+	return 0;
+}
+
+static void
+show_btf_plain(struct bpf_btf_info *info, int fd,
+	       struct btf_attach_table *btf_prog_table,
+	       struct btf_attach_table *btf_map_table)
+{
+	struct btf_attach_point *obj;
+	int n;
+
+	printf("%u: ", info->id);
+	printf("size %uB", info->btf_size);
+
+	n = 0;
+	hash_for_each_possible(btf_prog_table->table, obj, hash, info->id) {
+		if (obj->btf_id == info->id)
+			printf("%s%u", n++ == 0 ? "  prog_ids " : ",",
+			       obj->obj_id);
+	}
+
+	n = 0;
+	hash_for_each_possible(btf_map_table->table, obj, hash, info->id) {
+		if (obj->btf_id == info->id)
+			printf("%s%u", n++ == 0 ? "  map_ids " : ",",
+			       obj->obj_id);
+	}
+
+	printf("\n");
+}
+
+static void
+show_btf_json(struct bpf_btf_info *info, int fd,
+	      struct btf_attach_table *btf_prog_table,
+	      struct btf_attach_table *btf_map_table)
+{
+	struct btf_attach_point *obj;
+
+	jsonw_start_object(json_wtr);	/* btf object */
+	jsonw_uint_field(json_wtr, "id", info->id);
+	jsonw_uint_field(json_wtr, "size", info->btf_size);
+
+	jsonw_name(json_wtr, "prog_ids");
+	jsonw_start_array(json_wtr);	/* prog_ids */
+	hash_for_each_possible(btf_prog_table->table, obj, hash,
+			       info->id) {
+		if (obj->btf_id == info->id)
+			jsonw_uint(json_wtr, obj->obj_id);
+	}
+	jsonw_end_array(json_wtr);	/* prog_ids */
+
+	jsonw_name(json_wtr, "map_ids");
+	jsonw_start_array(json_wtr);	/* map_ids */
+	hash_for_each_possible(btf_map_table->table, obj, hash,
+			       info->id) {
+		if (obj->btf_id == info->id)
+			jsonw_uint(json_wtr, obj->obj_id);
+	}
+	jsonw_end_array(json_wtr);	/* map_ids */
+	jsonw_end_object(json_wtr);	/* btf object */
+}
+
+static int
+show_btf(int fd, struct btf_attach_table *btf_prog_table,
+	 struct btf_attach_table *btf_map_table)
+{
+	struct bpf_btf_info info = {};
+	__u32 len = sizeof(info);
+	int err;
+
+	err = bpf_obj_get_info_by_fd(fd, &info, &len);
+	if (err) {
+		p_err("can't get BTF object info: %s", strerror(errno));
+		return -1;
+	}
+
+	if (json_output)
+		show_btf_json(&info, fd, btf_prog_table, btf_map_table);
+	else
+		show_btf_plain(&info, fd, btf_prog_table, btf_map_table);
+
+	return 0;
+}
+
+static int do_show(int argc, char **argv)
+{
+	struct btf_attach_table btf_prog_table;
+	struct btf_attach_table btf_map_table;
+	int err, fd = -1;
+	__u32 id = 0;
+
+	if (argc == 2) {
+		fd = btf_parse_fd(&argc, &argv);
+		if (fd < 0)
+			return -1;
+	}
+
+	if (argc) {
+		if (fd >= 0)
+			close(fd);
+		return BAD_ARG();
+	}
+
+	hash_init(btf_prog_table.table);
+	hash_init(btf_map_table.table);
+	err = build_btf_tables(&btf_prog_table, &btf_map_table);
+	if (err) {
+		if (fd >= 0)
+			close(fd);
+		return err;
+	}
+
+	if (fd >= 0) {
+		err = show_btf(fd, &btf_prog_table, &btf_map_table);
+		close(fd);
+		goto exit_free;
+	}
+
+	if (json_output)
+		jsonw_start_array(json_wtr);	/* root array */
+
+	while (true) {
+		err = bpf_btf_get_next_id(id, &id);
+		if (err) {
+			if (errno == ENOENT) {
+				err = 0;
+				break;
+			}
+			p_err("can't get next BTF object: %s%s",
+			      strerror(errno),
+			      errno == EINVAL ? " -- kernel too old?" : "");
+			err = -1;
+			break;
+		}
+
+		fd = bpf_btf_get_fd_by_id(id);
+		if (fd < 0) {
+			if (errno == ENOENT)
+				continue;
+			p_err("can't get BTF object by id (%u): %s",
+			      id, strerror(errno));
+			err = -1;
+			break;
+		}
+
+		err = show_btf(fd, &btf_prog_table, &btf_map_table);
+		close(fd);
+		if (err)
+			break;
+	}
+
+	if (json_output)
+		jsonw_end_array(json_wtr);	/* root array */
+
+exit_free:
+	delete_btf_table(&btf_prog_table);
+	delete_btf_table(&btf_map_table);
+
+	return err;
+}
+
 static int do_help(int argc, char **argv)
 {
 	if (json_output) {
@@ -530,7 +947,8 @@ static int do_help(int argc, char **argv)
 	}
 
 	fprintf(stderr,
-		"Usage: %s btf dump BTF_SRC [format FORMAT]\n"
+		"Usage: %s btf { show | list } [id BTF_ID]\n"
+		"       %s btf dump BTF_SRC [format FORMAT]\n"
 		"       %s btf help\n"
 		"\n"
 		"       BTF_SRC := { id BTF_ID | prog PROG | map MAP [{key | value | kv | all}] | file FILE }\n"
@@ -539,12 +957,14 @@ static int do_help(int argc, char **argv)
 		"       " HELP_SPEC_PROGRAM "\n"
 		"       " HELP_SPEC_OPTIONS "\n"
 		"",
-		bin_name, bin_name);
+		bin_name, bin_name, bin_name);
 
 	return 0;
 }
 
 static const struct cmd cmds[] = {
+	{ "show",	do_show },
+	{ "list",	do_show },
 	{ "help",	do_help },
 	{ "dump",	do_dump },
 	{ 0 }