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author | Jakub Kicinski <jakub.kicinski@netronome.com> | 2017-10-05 06:10:04 +0300 |
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committer | David S. Miller <davem@davemloft.net> | 2017-10-05 07:45:06 +0300 |
commit | 71bb428fe2c19512ac671d5ee16ef3e73e1b49a8 (patch) | |
tree | 69a3005a095804dcdb3600b177d019fd2fba2c24 /tools/bpf/bpftool/jit_disasm.c | |
parent | a92bb546cff0b31d96d5919ebfeda9c678756b42 (diff) | |
download | linux-71bb428fe2c19512ac671d5ee16ef3e73e1b49a8.tar.xz |
tools: bpf: add bpftool
Add a simple tool for querying and updating BPF objects on the system.
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools/bpf/bpftool/jit_disasm.c')
-rw-r--r-- | tools/bpf/bpftool/jit_disasm.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c new file mode 100644 index 000000000000..70e480b59e9d --- /dev/null +++ b/tools/bpf/bpftool/jit_disasm.c @@ -0,0 +1,87 @@ +/* + * Based on: + * + * Minimal BPF JIT image disassembler + * + * Disassembles BPF JIT compiler emitted opcodes back to asm insn's for + * debugging or verification purposes. + * + * Copyright 2013 Daniel Borkmann <daniel@iogearbox.net> + * Licensed under the GNU General Public License, version 2.0 (GPLv2) + */ + +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <assert.h> +#include <unistd.h> +#include <string.h> +#include <bfd.h> +#include <dis-asm.h> +#include <sys/types.h> +#include <sys/stat.h> + +static void get_exec_path(char *tpath, size_t size) +{ + ssize_t len; + char *path; + + snprintf(tpath, size, "/proc/%d/exe", (int) getpid()); + tpath[size - 1] = 0; + + path = strdup(tpath); + assert(path); + + len = readlink(path, tpath, size - 1); + assert(len > 0); + tpath[len] = 0; + + free(path); +} + +void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes) +{ + disassembler_ftype disassemble; + struct disassemble_info info; + int count, i, pc = 0; + char tpath[256]; + bfd *bfdf; + + if (!len) + return; + + memset(tpath, 0, sizeof(tpath)); + get_exec_path(tpath, sizeof(tpath)); + + bfdf = bfd_openr(tpath, NULL); + assert(bfdf); + assert(bfd_check_format(bfdf, bfd_object)); + + init_disassemble_info(&info, stdout, (fprintf_ftype) fprintf); + info.arch = bfd_get_arch(bfdf); + info.mach = bfd_get_mach(bfdf); + info.buffer = image; + info.buffer_length = len; + + disassemble_init_for_target(&info); + + disassemble = disassembler(bfdf); + assert(disassemble); + + do { + printf("%4x:\t", pc); + + count = disassemble(pc, &info); + + if (opcodes) { + printf("\n\t"); + for (i = 0; i < count; ++i) + printf("%02x ", (uint8_t) image[pc + i]); + } + printf("\n"); + + pc += count; + } while (count > 0 && pc < len); + + bfd_close(bfdf); +} |