[PATCH bpf-next 7/8] tools: bpftool: new command-line option and documentation for 'visual'

[Jakub Kicinski]

From: Jiong Wang <jiong.w...@netronome.com>

This patch adds new command-line option for visualizing the xlated eBPF
sequence.

Documentations are updated accordingly.

Usage:

  bpftool prog dump xlated id 2 visual

Reviewed-by: Quentin Monnet <quentin.mon...@netronome.com>
Signed-off-by: Jiong Wang <jiong.w...@netronome.com>
Acked-by: Jakub Kicinski <jakub.kicin...@netronome.com>
---
 tools/bpf/bpftool/Documentation/bpftool-prog.rst | 18 ++++++++++++------
 tools/bpf/bpftool/prog.c                         | 12 +++++++++++-
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst 
b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index e4ceee7f2dff..67ca6c69376c 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -21,7 +21,7 @@ MAP COMMANDS
 =============
 
 |      **bpftool** **prog { show | list }** [*PROG*]
-|      **bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | 
**opcodes**}]
+|      **bpftool** **prog dump xlated** *PROG* [{**file** *FILE* | **opcodes** 
| **visual**}]
 |      **bpftool** **prog dump jited**  *PROG* [{**file** *FILE* | 
**opcodes**}]
 |      **bpftool** **prog pin** *PROG* *FILE*
 |      **bpftool** **prog load** *OBJ* *FILE*
@@ -39,12 +39,18 @@ 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* | **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.
+       **bpftool prog dump xlated** *PROG* [{ **file** *FILE* | **opcodes** | 
**visual** }]
+                 Dump eBPF instructions of the program from the kernel. By
+                 default, eBPF will be disassembled and printed to standard
+                 output in human-readable format. In this case, **opcodes**
+                 controls if raw opcodes should be printed as well.
 
-                 **opcodes** controls if raw opcodes will be printed.
+                 If **file** is specified, the binary image will instead be
+                 written to *FILE*.
+
+                 If **visual** is specified, control flow graph (CFG) will be
+                 built instead, and eBPF instructions will be presented with
+                 CFG in DOT format, on standard output.
 
        **bpftool prog dump jited**  *PROG* [{ **file** *FILE* | **opcodes** }]
                  Dump jited image (host machine code) of the program.
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index c5afee9838e6..f7a810897eac 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -47,6 +47,7 @@
 #include <bpf.h>
 #include <libbpf.h>
 
+#include "cfg.h"
 #include "main.h"
 #include "xlated_dumper.h"
 
@@ -415,6 +416,7 @@ static int do_dump(int argc, char **argv)
        unsigned int buf_size;
        char *filepath = NULL;
        bool opcodes = false;
+       bool visual = false;
        unsigned char *buf;
        __u32 *member_len;
        __u64 *member_ptr;
@@ -453,6 +455,9 @@ static int do_dump(int argc, char **argv)
        } else if (is_prefix(*argv, "opcodes")) {
                opcodes = true;
                NEXT_ARG();
+       } else if (is_prefix(*argv, "visual")) {
+               visual = true;
+               NEXT_ARG();
        }
 
        if (argc) {
@@ -536,6 +541,11 @@ static int do_dump(int argc, char **argv)
                }
 
                disasm_print_insn(buf, *member_len, opcodes, name);
+       } else if (visual) {
+               if (json_output)
+                       jsonw_null(json_wtr);
+               else
+                       dump_xlated_cfg(buf, *member_len);
        } else {
                kernel_syms_load(&dd);
                if (json_output)
@@ -596,7 +606,7 @@ static int do_help(int argc, char **argv)
 
        fprintf(stderr,
                "Usage: %s %s { show | list } [PROG]\n"
-               "       %s %s dump xlated PROG [{ file FILE | opcodes }]\n"
+               "       %s %s dump xlated PROG [{ file FILE | opcodes | visual 
}]\n"
                "       %s %s dump jited  PROG [{ file FILE | opcodes }]\n"
                "       %s %s pin   PROG FILE\n"
                "       %s %s load  OBJ  FILE\n"
-- 
2.15.1