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tools: bpftool: use the kernel's instruction printer

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

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jakub Kicinski 2017-10-09 10:30:13 -07:00 committed by David S. Miller
parent f4ac7e0b5c
commit c9c35995bc
4 changed files with 51 additions and 21 deletions
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11
tools/bpf/bpftool/Documentation/bpftool-prog.rst
View File

@ -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.

7
tools/bpf/bpftool/Makefile
View File

@ -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)

10
tools/bpf/bpftool/main.h
View File

@ -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; })

44
tools/bpf/bpftool/prog.c
View File

@ -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 {
disasm_print_insn(buf, *member_len, opcodes);
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"