tools bpftool: Fix compilation error with new binutils

binutils changed the signature of init_disassemble_info(), which now causes
compilation to fail for tools/bpf/bpftool/jit_disasm.c, e.g. on debian
unstable.

Relevant binutils commit:

  https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=60a3da00bd5407f07

Wire up the feature test and switch to init_disassemble_info_compat(),
which were introduced in prior commits, fixing the compilation failure.

I verified that bpftool can still disassemble bpf programs, both with an
old and new dis-asm.h API. There are no output changes for plain and json
formats. When comparing the output from old binutils (2.35)
to new bintuils with the patch (upstream snapshot) there are a few output
differences, but they are unrelated to this patch. An example hunk is:

     2f:	pop    %r14
     31:	pop    %r13
     33:	pop    %rbx
  -  34:	leaveq
  -  35:	retq
  +  34:	leave
  +  35:	ret

Signed-off-by: Andres Freund <andres@anarazel.de>
Acked-by: Quentin Monnet <quentin@isovalent.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Ben Hutchings <benh@debian.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Sedat Dilek <sedat.dilek@gmail.com>
Cc: bpf@vger.kernel.org
Link: http://lore.kernel.org/lkml/20220622181918.ykrs5rsnmx3og4sv@alap3.anarazel.de
Link: https://lore.kernel.org/r/20220801013834.156015-8-andres@anarazel.de
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
index c6d2c77..436e671 100644 (file)
--- a/tools/bpf/bpftool/Makefile
+++ b/tools/bpf/bpftool/Makefile
@@ -93,7 +93,7 @@ INSTALL ?= install
 RM ?= rm -f
 
 FEATURE_USER = .bpftool
-FEATURE_TESTS = libbfd disassembler-four-args zlib libcap \
+FEATURE_TESTS = libbfd disassembler-four-args disassembler-init-styled zlib libcap \
        clang-bpf-co-re
 FEATURE_DISPLAY = libbfd disassembler-four-args zlib libcap \
        clang-bpf-co-re
@@ -117,6 +117,9 @@ endif
 ifeq ($(feature-disassembler-four-args), 1)
 CFLAGS += -DDISASM_FOUR_ARGS_SIGNATURE
 endif
+ifeq ($(feature-disassembler-init-styled), 1)
+    CFLAGS += -DDISASM_INIT_STYLED
+endif
 
 LIBS = $(LIBBPF) -lelf -lz
 LIBS_BOOTSTRAP = $(LIBBPF_BOOTSTRAP) -lelf -lz

diff --git a/tools/bpf/bpftool/jit_disasm.c b/tools/bpf/bpftool/jit_disasm.c
index 24734f2..aaf99a0 100644 (file)
--- a/tools/bpf/bpftool/jit_disasm.c
+++ b/tools/bpf/bpftool/jit_disasm.c
@@ -24,6 +24,7 @@
 #include <sys/stat.h>
 #include <limits.h>
 #include <bpf/libbpf.h>
+#include <tools/dis-asm-compat.h>
 
 #include "json_writer.h"
 #include "main.h"
@@ -39,15 +40,12 @@ static void get_exec_path(char *tpath, size_t size)
 }
 
 static int oper_count;
-static int fprintf_json(void *out, const char *fmt, ...)
+static int printf_json(void *out, const char *fmt, va_list ap)
 {
-       va_list ap;
        char *s;
        int err;
 
-       va_start(ap, fmt);
        err = vasprintf(&s, fmt, ap);
-       va_end(ap);
        if (err < 0)
                return -1;
 
@@ -73,6 +71,32 @@ static int fprintf_json(void *out, const char *fmt, ...)
        return 0;
 }
 
+static int fprintf_json(void *out, const char *fmt, ...)
+{
+       va_list ap;
+       int r;
+
+       va_start(ap, fmt);
+       r = printf_json(out, fmt, ap);
+       va_end(ap);
+
+       return r;
+}
+
+static int fprintf_json_styled(void *out,
+                              enum disassembler_style style __maybe_unused,
+                              const char *fmt, ...)
+{
+       va_list ap;
+       int r;
+
+       va_start(ap, fmt);
+       r = printf_json(out, fmt, ap);
+       va_end(ap);
+
+       return r;
+}
+
 void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
                       const char *arch, const char *disassembler_options,
                       const struct btf *btf,
@@ -99,11 +123,13 @@ void disasm_print_insn(unsigned char *image, ssize_t len, int opcodes,
        assert(bfd_check_format(bfdf, bfd_object));
 
        if (json_output)
-               init_disassemble_info(&info, stdout,
-                                     (fprintf_ftype) fprintf_json);
+               init_disassemble_info_compat(&info, stdout,
+                                            (fprintf_ftype) fprintf_json,
+                                            fprintf_json_styled);
        else
-               init_disassemble_info(&info, stdout,
-                                     (fprintf_ftype) fprintf);
+               init_disassemble_info_compat(&info, stdout,
+                                            (fprintf_ftype) fprintf,
+                                            fprintf_styled);
 
        /* Update architecture info for offload. */
        if (arch) {