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Commit c9c35995 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

tools: bpftool: use the kernel's instruction printer 



Compile the instruction printer from kernel/bpf and use it
for disassembling "translated" eBPF code.

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: default avatarSimon Horman <simon.horman@netronome.com>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f4ac7e0b

tools/bpf/bpftool/Documentation/bpftool-prog.rst

+7 −4
Original line number Diff line number Diff line
@@ -11,7 +11,7 @@ SYNOPSIS 
========



|	**bpftool** prog show [*PROG*]

|	**bpftool** prog dump xlated *PROG*  file *FILE*

|	**bpftool** prog dump xlated *PROG* [file *FILE*] [opcodes]

|	**bpftool** prog dump jited  *PROG* [file *FILE*] [opcodes]

|	**bpftool** prog pin *PROG* *FILE*

|	**bpftool** prog help
@@ -28,9 +28,12 @@ DESCRIPTION 
		  Output will start with program ID followed by program type and

		  zero or more named attributes (depending on kernel version).



	**bpftool prog dump xlated** *PROG*  **file** *FILE*

		  Dump eBPF instructions of the program from the kernel to a

		  file.

	**bpftool prog dump xlated** *PROG* [**file** *FILE*] [**opcodes**]

		  Dump eBPF instructions of the program from the kernel.

		  If *FILE* is specified image will be written to a file,

		  otherwise it will be disassembled and printed to stdout.



		  **opcodes** controls if raw opcodes will be printed.



	**bpftool prog dump jited**  *PROG* [**file** *FILE*] [**opcodes**]

		  Dump jited image (host machine code) of the program.

tools/bpf/bpftool/Makefile

+5 −2
Original line number Diff line number Diff line
@@ -51,7 +51,7 @@ CC = gcc 


CFLAGS += -O2

CFLAGS += -W -Wall -Wextra -Wno-unused-parameter -Wshadow

CFLAGS += -D__EXPORTED_HEADERS__ -I$(srctree)/tools/include/uapi -I$(srctree)/tools/include -I$(srctree)/tools/lib/bpf

CFLAGS += -D__EXPORTED_HEADERS__ -I$(srctree)/tools/include/uapi -I$(srctree)/tools/include -I$(srctree)/tools/lib/bpf -I$(srctree)/kernel/bpf/

LIBS = -lelf -lbfd -lopcodes $(LIBBPF)



include $(wildcard *.d)
@@ -59,7 +59,10 @@ include $(wildcard *.d) 
all: $(OUTPUT)bpftool



SRCS=$(wildcard *.c)

OBJS=$(patsubst %.c,$(OUTPUT)%.o,$(SRCS))

OBJS=$(patsubst %.c,$(OUTPUT)%.o,$(SRCS)) $(OUTPUT)disasm.o



$(OUTPUT)disasm.o: $(srctree)/kernel/bpf/disasm.c

	$(QUIET_CC)$(COMPILE.c) -MMD -o $@ $<



$(OUTPUT)bpftool: $(OBJS) $(LIBBPF)

	$(QUIET_LINK)$(CC) $(CFLAGS) -o $@ $^ $(LIBS)

tools/bpf/bpftool/main.h

+3 −7
Original line number Diff line number Diff line
@@ -36,11 +36,12 @@ 
#ifndef __BPF_TOOL_H

#define __BPF_TOOL_H



/* BFD and kernel.h both define GCC_VERSION, differently */

#undef GCC_VERSION

#include <stdbool.h>

#include <stdio.h>

#include <linux/bpf.h>



#define ARRAY_SIZE(a)	(sizeof(a) / sizeof(a[0]))

#include <linux/kernel.h>



#define err(msg...)	fprintf(stderr, "Error: " msg)

#define warn(msg...)	fprintf(stderr, "Warning: " msg)
@@ -48,11 +49,6 @@ 


#define ptr_to_u64(ptr)	((__u64)(unsigned long)(ptr))



#define min(a, b)							\

	({ typeof(a) _a = (a); typeof(b) _b = (b); _a > _b ? _b : _a; })

#define max(a, b)							\

	({ typeof(a) _a = (a); typeof(b) _b = (b); _a < _b ? _b : _a; })



#define NEXT_ARG()	({ argc--; argv++; if (argc < 0) usage(); })

#define NEXT_ARGP()	({ (*argc)--; (*argv)++; if (*argc < 0) usage(); })

#define BAD_ARG()	({ err("what is '%s'?\n", *argv); -1; })

tools/bpf/bpftool/prog.c

+36 −8
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 


#include <errno.h>

#include <fcntl.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>
@@ -46,6 +47,7 @@ 
#include <bpf.h>



#include "main.h"

#include "disasm.h"



static const char * const prog_type_name[] = {

	[BPF_PROG_TYPE_UNSPEC]		= "unspec",
@@ -297,11 +299,39 @@ static int do_show(int argc, char **argv) 
	return 0;

}



static void print_insn(struct bpf_verifier_env *env, const char *fmt, ...)

{

	va_list args;



	va_start(args, fmt);

	vprintf(fmt, args);

	va_end(args);

}



static void dump_xlated(void *buf, unsigned int len, bool opcodes)

{

	struct bpf_insn *insn = buf;

	unsigned int i;



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

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

		print_bpf_insn(print_insn, NULL, insn + i, true);



		if (opcodes) {

			printf("       ");

			print_hex(insn + i, 8, " ");

			printf("\n");

		}



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

			i++;

	}

}



static int do_dump(int argc, char **argv)

{

	struct bpf_prog_info info = {};

	__u32 len = sizeof(info);

	bool can_disasm = false;

	unsigned int buf_size;

	char *filepath = NULL;

	bool opcodes = false;
@@ -315,7 +345,6 @@ static int do_dump(int argc, char **argv) 
	if (is_prefix(*argv, "jited")) {

		member_len = &info.jited_prog_len;

		member_ptr = &info.jited_prog_insns;

		can_disasm = true;

	} else if (is_prefix(*argv, "xlated")) {

		member_len = &info.xlated_prog_len;

		member_ptr = &info.xlated_prog_insns;
@@ -346,10 +375,6 @@ static int do_dump(int argc, char **argv) 
		NEXT_ARG();

	}



	if (!filepath && !can_disasm) {

		err("expected 'file' got %s\n", *argv);

		return -1;

	}

	if (argc) {

		usage();

		return -1;
@@ -409,7 +434,10 @@ static int do_dump(int argc, char **argv) 
			goto err_free;

		}

	} else {

		if (member_len == &info.jited_prog_len)

			disasm_print_insn(buf, *member_len, opcodes);

		else

			dump_xlated(buf, *member_len, opcodes);

	}



	free(buf);
@@ -430,7 +458,7 @@ static int do_help(int argc, char **argv) 
{

	fprintf(stderr,

		"Usage: %s %s show [PROG]\n"

		"       %s %s dump xlated PROG  file FILE\n"

		"       %s %s dump xlated PROG [file FILE] [opcodes]\n"

		"       %s %s dump jited  PROG [file FILE] [opcodes]\n"

		"       %s %s pin   PROG FILE\n"

		"       %s %s help\n"