From c9c35995bcf812ee8136f634c25bc6ccc3021d4c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Mon, 9 Oct 2017 10:30:13 -0700 Subject: [PATCH] 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: Jakub Kicinski Reviewed-by: Simon Horman Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- .../bpftool/Documentation/bpftool-prog.rst | 11 +++-- tools/bpf/bpftool/Makefile | 7 ++- tools/bpf/bpftool/main.h | 10 ++--- tools/bpf/bpftool/prog.c | 44 +++++++++++++++---- 4 files changed, 51 insertions(+), 21 deletions(-) diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst index 57fc4b9924ea..04d12f768f06 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst @@ -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. diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile index 8705ee44664d..4f339824ca57 100644 --- a/tools/bpf/bpftool/Makefile +++ b/tools/bpf/bpftool/Makefile @@ -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) diff --git a/tools/bpf/bpftool/main.h b/tools/bpf/bpftool/main.h index 85d2d7870a58..8e809b2bb311 100644 --- a/tools/bpf/bpftool/main.h +++ b/tools/bpf/bpftool/main.h @@ -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 #include #include - -#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0])) +#include #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; }) diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c index 421ba89ce86a..9e2681c83717 100644 --- a/tools/bpf/bpftool/prog.c +++ b/tools/bpf/bpftool/prog.c @@ -35,6 +35,7 @@ #include #include +#include #include #include #include @@ -46,6 +47,7 @@ #include #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"