Commit 254471e5 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

tools/bpf: bpftool: add support for func types 



This patch added support to print function signature
if btf func_info is available. Note that ksym
now uses function name instead of prog_name as
prog_name has a limit of 16 bytes including
ending '\0'.

The following is a sample output for selftests
test_btf with file test_btf_haskv.o for translated insns
and jited insns respectively.

  $ bpftool prog dump xlated id 1
  int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
     0: (85) call pc+2#bpf_prog_2dcecc18072623fc_test_long_fname_1
     1: (b7) r0 = 0
     2: (95) exit
  int test_long_fname_1(struct dummy_tracepoint_args * arg):
     3: (85) call pc+1#bpf_prog_89d64e4abf0f0126_test_long_fname_2
     4: (95) exit
  int test_long_fname_2(struct dummy_tracepoint_args * arg):
     5: (b7) r2 = 0
     6: (63) *(u32 *)(r10 -4) = r2
     7: (79) r1 = *(u64 *)(r1 +8)
     ...
     22: (07) r1 += 1
     23: (63) *(u32 *)(r0 +4) = r1
     24: (95) exit

  $ bpftool prog dump jited id 1
  int _dummy_tracepoint(struct dummy_tracepoint_args * arg):
  bpf_prog_b07ccb89267cf242__dummy_tracepoint:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    3c:   add    $0x28,%rbp
    40:   leaveq
    41:   retq

  int test_long_fname_1(struct dummy_tracepoint_args * arg):
  bpf_prog_2dcecc18072623fc_test_long_fname_1:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    3a:   add    $0x28,%rbp
    3e:   leaveq
    3f:   retq

  int test_long_fname_2(struct dummy_tracepoint_args * arg):
  bpf_prog_89d64e4abf0f0126_test_long_fname_2:
     0:   push   %rbp
     1:   mov    %rsp,%rbp
    ......
    80:   add    $0x28,%rbp
    84:   leaveq
    85:   retq

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 999d82cb

tools/bpf/bpftool/btf_dumper.c

+136 −0
Original line number Diff line number Diff line
@@ -249,3 +249,139 @@ int btf_dumper_type(const struct btf_dumper *d, __u32 type_id, 
{

	return btf_dumper_do_type(d, type_id, 0, data);

}



#define BTF_PRINT_ARG(...)						\

	do {								\

		pos += snprintf(func_sig + pos, size - pos,		\

				__VA_ARGS__);				\

		if (pos >= size)					\

			return -1;					\

	} while (0)

#define BTF_PRINT_TYPE(type)					\

	do {								\

		pos = __btf_dumper_type_only(btf, type, func_sig,	\

					     pos, size);		\

		if (pos == -1)						\

			return -1;					\

	} while (0)



static int btf_dump_func(const struct btf *btf, char *func_sig,

			 const struct btf_type *func_proto,

			 const struct btf_type *func, int pos, int size);



static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,

				  char *func_sig, int pos, int size)

{

	const struct btf_type *proto_type;

	const struct btf_array *array;

	const struct btf_type *t;



	if (!type_id) {

		BTF_PRINT_ARG("void ");

		return pos;

	}



	t = btf__type_by_id(btf, type_id);



	switch (BTF_INFO_KIND(t->info)) {

	case BTF_KIND_INT:

		BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));

		break;

	case BTF_KIND_STRUCT:

		BTF_PRINT_ARG("struct %s ",

			      btf__name_by_offset(btf, t->name_off));

		break;

	case BTF_KIND_UNION:

		BTF_PRINT_ARG("union %s ",

			      btf__name_by_offset(btf, t->name_off));

		break;

	case BTF_KIND_ENUM:

		BTF_PRINT_ARG("enum %s ",

			      btf__name_by_offset(btf, t->name_off));

		break;

	case BTF_KIND_ARRAY:

		array = (struct btf_array *)(t + 1);

		BTF_PRINT_TYPE(array->type);

		BTF_PRINT_ARG("[%d]", array->nelems);

		break;

	case BTF_KIND_PTR:

		BTF_PRINT_TYPE(t->type);

		BTF_PRINT_ARG("* ");

		break;

	case BTF_KIND_UNKN:

	case BTF_KIND_FWD:

	case BTF_KIND_TYPEDEF:

		return -1;

	case BTF_KIND_VOLATILE:

		BTF_PRINT_ARG("volatile ");

		BTF_PRINT_TYPE(t->type);

		break;

	case BTF_KIND_CONST:

		BTF_PRINT_ARG("const ");

		BTF_PRINT_TYPE(t->type);

		break;

	case BTF_KIND_RESTRICT:

		BTF_PRINT_ARG("restrict ");

		BTF_PRINT_TYPE(t->type);

		break;

	case BTF_KIND_FUNC_PROTO:

		pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);

		if (pos == -1)

			return -1;

		break;

	case BTF_KIND_FUNC:

		proto_type = btf__type_by_id(btf, t->type);

		pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);

		if (pos == -1)

			return -1;

		break;

	default:

		return -1;

	}



	return pos;

}



static int btf_dump_func(const struct btf *btf, char *func_sig,

			 const struct btf_type *func_proto,

			 const struct btf_type *func, int pos, int size)

{

	int i, vlen;



	BTF_PRINT_TYPE(func_proto->type);

	if (func)

		BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));

	else

		BTF_PRINT_ARG("(");

	vlen = BTF_INFO_VLEN(func_proto->info);

	for (i = 0; i < vlen; i++) {

		struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];



		if (i)

			BTF_PRINT_ARG(", ");

		if (arg->type) {

			BTF_PRINT_TYPE(arg->type);

			BTF_PRINT_ARG("%s",

				      btf__name_by_offset(btf, arg->name_off));

		} else {

			BTF_PRINT_ARG("...");

		}

	}

	BTF_PRINT_ARG(")");



	return pos;

}



void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,

			  int size)

{

	int err;



	func_sig[0] = '\0';

	if (!btf)

		return;



	err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);

	if (err < 0)

		func_sig[0] = '\0';

}

tools/bpf/bpftool/main.h

+2 −0
Original line number Diff line number Diff line
@@ -187,6 +187,8 @@ struct btf_dumper { 
 */

int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,

		    const void *data);

void btf_dumper_type_only(const struct btf *btf, __u32 func_type_id,

			  char *func_only, int size);



struct nlattr;

struct ifinfomsg;

tools/bpf/bpftool/prog.c

+56 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ 
#include <linux/err.h>



#include <bpf.h>

#include <btf.h>

#include <libbpf.h>



#include "cfg.h"
@@ -451,14 +452,19 @@ static int do_dump(int argc, char **argv) 
	struct bpf_prog_info info = {};

	unsigned int *func_lens = NULL;

	const char *disasm_opt = NULL;

	unsigned int finfo_rec_size;

	unsigned int nr_func_ksyms;

	unsigned int nr_func_lens;

	struct dump_data dd = {};

	__u32 len = sizeof(info);

	struct btf *btf = NULL;

	void *func_info = NULL;

	unsigned int finfo_cnt;

	unsigned int buf_size;

	char *filepath = NULL;

	bool opcodes = false;

	bool visual = false;

	char func_sig[1024];

	unsigned char *buf;

	__u32 *member_len;

	__u64 *member_ptr;
@@ -551,6 +557,17 @@ static int do_dump(int argc, char **argv) 
		}

	}



	finfo_cnt = info.func_info_cnt;

	finfo_rec_size = info.func_info_rec_size;

	if (finfo_cnt && finfo_rec_size) {

		func_info = malloc(finfo_cnt * finfo_rec_size);

		if (!func_info) {

			p_err("mem alloc failed");

			close(fd);

			goto err_free;

		}

	}



	memset(&info, 0, sizeof(info));



	*member_ptr = ptr_to_u64(buf);
@@ -559,6 +576,9 @@ static int do_dump(int argc, char **argv) 
	info.nr_jited_ksyms = nr_func_ksyms;

	info.jited_func_lens = ptr_to_u64(func_lens);

	info.nr_jited_func_lens = nr_func_lens;

	info.func_info_cnt = finfo_cnt;

	info.func_info_rec_size = finfo_rec_size;

	info.func_info = ptr_to_u64(func_info);



	err = bpf_obj_get_info_by_fd(fd, &info, &len);

	close(fd);
@@ -582,6 +602,18 @@ static int do_dump(int argc, char **argv) 
		goto err_free;

	}



	if (info.func_info_cnt != finfo_cnt) {

		p_err("incorrect func_info_cnt %d vs. expected %d",

		      info.func_info_cnt, finfo_cnt);

		goto err_free;

	}



	if (info.func_info_rec_size != finfo_rec_size) {

		p_err("incorrect func_info_rec_size %d vs. expected %d",

		      info.func_info_rec_size, finfo_rec_size);

		goto err_free;

	}



	if ((member_len == &info.jited_prog_len &&

	     info.jited_prog_insns == 0) ||

	    (member_len == &info.xlated_prog_len &&
@@ -590,6 +622,11 @@ static int do_dump(int argc, char **argv) 
		goto err_free;

	}



	if (info.btf_id && btf_get_from_id(info.btf_id, &btf)) {

		p_err("failed to get btf");

		goto err_free;

	}



	if (filepath) {

		fd = open(filepath, O_WRONLY | O_CREAT | O_TRUNC, 0600);

		if (fd < 0) {
@@ -622,6 +659,7 @@ static int do_dump(int argc, char **argv) 


		if (info.nr_jited_func_lens && info.jited_func_lens) {

			struct kernel_sym *sym = NULL;

			struct bpf_func_info *record;

			char sym_name[SYM_MAX_NAME];

			unsigned char *img = buf;

			__u64 *ksyms = NULL;
@@ -648,12 +686,25 @@ static int do_dump(int argc, char **argv) 
					strcpy(sym_name, "unknown");

				}



				if (func_info) {

					record = func_info + i * finfo_rec_size;

					btf_dumper_type_only(btf, record->type_id,

							     func_sig,

							     sizeof(func_sig));

				}



				if (json_output) {

					jsonw_start_object(json_wtr);

					if (func_info && func_sig[0] != '\0') {

						jsonw_name(json_wtr, "proto");

						jsonw_string(json_wtr, func_sig);

					}

					jsonw_name(json_wtr, "name");

					jsonw_string(json_wtr, sym_name);

					jsonw_name(json_wtr, "insns");

				} else {

					if (func_info && func_sig[0] != '\0')

						printf("%s:\n", func_sig);

					printf("%s:\n", sym_name);

				}
@@ -682,6 +733,9 @@ static int do_dump(int argc, char **argv) 
		kernel_syms_load(&dd);

		dd.nr_jited_ksyms = info.nr_jited_ksyms;

		dd.jited_ksyms = (__u64 *) info.jited_ksyms;

		dd.btf = btf;

		dd.func_info = func_info;

		dd.finfo_rec_size = finfo_rec_size;



		if (json_output)

			dump_xlated_json(&dd, buf, *member_len, opcodes);
@@ -693,12 +747,14 @@ static int do_dump(int argc, char **argv) 
	free(buf);

	free(func_ksyms);

	free(func_lens);

	free(func_info);

	return 0;



err_free:

	free(buf);

	free(func_ksyms);

	free(func_lens);

	free(func_info);

	return -1;

}

tools/bpf/bpftool/xlated_dumper.c

+33 −0
Original line number Diff line number Diff line
@@ -242,11 +242,15 @@ void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len, 
		.cb_imm		= print_imm,

		.private_data	= dd,

	};

	struct bpf_func_info *record;

	struct bpf_insn *insn = buf;

	struct btf *btf = dd->btf;

	bool double_insn = false;

	char func_sig[1024];

	unsigned int i;



	jsonw_start_array(json_wtr);

	record = dd->func_info;

	for (i = 0; i < len / sizeof(*insn); i++) {

		if (double_insn) {

			double_insn = false;
@@ -255,6 +259,20 @@ void dump_xlated_json(struct dump_data *dd, void *buf, unsigned int len, 
		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);



		jsonw_start_object(json_wtr);



		if (btf && record) {

			if (record->insn_offset == i) {

				btf_dumper_type_only(btf, record->type_id,

						     func_sig,

						     sizeof(func_sig));

				if (func_sig[0] != '\0') {

					jsonw_name(json_wtr, "proto");

					jsonw_string(json_wtr, func_sig);

				}

				record = (void *)record + dd->finfo_rec_size;

			}

		}



		jsonw_name(json_wtr, "disasm");

		print_bpf_insn(&cbs, insn + i, true);
@@ -297,16 +315,31 @@ void dump_xlated_plain(struct dump_data *dd, void *buf, unsigned int len, 
		.cb_imm		= print_imm,

		.private_data	= dd,

	};

	struct bpf_func_info *record;

	struct bpf_insn *insn = buf;

	struct btf *btf = dd->btf;

	bool double_insn = false;

	char func_sig[1024];

	unsigned int i;



	record = dd->func_info;

	for (i = 0; i < len / sizeof(*insn); i++) {

		if (double_insn) {

			double_insn = false;

			continue;

		}



		if (btf && record) {

			if (record->insn_offset == i) {

				btf_dumper_type_only(btf, record->type_id,

						     func_sig,

						     sizeof(func_sig));

				if (func_sig[0] != '\0')

					printf("%s:\n", func_sig);

				record = (void *)record + dd->finfo_rec_size;

			}

		}



		double_insn = insn[i].code == (BPF_LD | BPF_IMM | BPF_DW);



		printf("% 4d: ", i);

tools/bpf/bpftool/xlated_dumper.h

+3 −0
Original line number Diff line number Diff line
@@ -51,6 +51,9 @@ struct dump_data { 
	__u32 sym_count;

	__u64 *jited_ksyms;

	__u32 nr_jited_ksyms;

	struct btf *btf;

	void *func_info;

	__u32 finfo_rec_size;

	char scratch_buff[SYM_MAX_NAME + 8];

};

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