linux.git/tools/bpf, branch v5.0-rc2

tools: bpftool: do not force gcc as CC

2018-12-19T20:57:25+00:00

This allows transparent cross-compilation with CROSS_COMPILE by
relying on 7ed1c1901fe5 ("tools: fix cross-compile var clobbering").

Signed-off-by: Ivan Babrou 
Signed-off-by: Daniel Borkmann

tools: bpftool: add an option to prevent auto-mount of bpffs, tracefs

2018-12-18T13:47:17+00:00

In order to make life easier for users, bpftool automatically attempts
to mount the BPF virtual file system, if it is not mounted already,
before trying to pin objects in it. Similarly, it attempts to mount
tracefs if necessary before trying to dump the trace pipe to the
console.

While mounting file systems on-the-fly can improve user experience, some
administrators might prefer to avoid that. Let's add an option to block
these mount attempts. Note that it does not prevent automatic mounting
of tracefs by debugfs for the "bpftool prog tracelog" command.

Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: attempt to mount tracefs if required for tracelog cmd

2018-12-18T13:47:17+00:00

As a follow-up to commit 30da46b5dc3a ("tools: bpftool: add a command to
dump the trace pipe"), attempt to mount the tracefs virtual file system
if it is not detected on the system before trying to dump content of the
tracing pipe on an invocation of "bpftool prog tracelog".

Usually, tracefs in automatically mounted by debugfs when the user tries
to access it (e.g. "ls /sys/kernel/debug/tracing" mounts the tracefs).
So if we failed to find it, it is probably that debugfs is not here
either. Therefore, we just attempt a single mount, at a location that
does not involve debugfs: /sys/kernel/tracing.

Suggested-by: Daniel Borkmann 
Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: support pretty print with kind_flag set

2018-12-18T00:12:00+00:00

The following example shows map pretty print with structures
which include bitfield members.

  enum A { A1, A2, A3, A4, A5 };
  typedef enum A ___A;
  struct tmp_t {
       char a1:4;
       int  a2:4;
       int  :4;
       __u32 a3:4;
       int b;
       ___A b1:4;
       enum A b2:4;
  };
  struct bpf_map_def SEC("maps") tmpmap = {
       .type = BPF_MAP_TYPE_ARRAY,
       .key_size = sizeof(__u32),
       .value_size = sizeof(struct tmp_t),
       .max_entries = 1,
  };
  BPF_ANNOTATE_KV_PAIR(tmpmap, int, struct tmp_t);

and the following map update in the bpf program:

  key = 0;
  struct tmp_t t = {};
  t.a1 = 2;
  t.a2 = 4;
  t.a3 = 6;
  t.b = 7;
  t.b1 = 8;
  t.b2 = 10;
  bpf_map_update_elem(&tmpmap, &key, &t, 0);

With this patch, I am able to print out the map values
correctly with this patch:
bpftool map dump id 187
  [{
        "key": 0,
        "value": {
            "a1": 0x2,
            "a2": 0x4,
            "a3": 0x6,
            "b": 7,
            "b1": 0x8,
            "b2": 0xa
        }
    }
  ]

Previously, if a function prototype argument has a typedef
type, the prototype is not printed since
function __btf_dumper_type_only() bailed out with error
if the type is a typedef. This commit corrected this
behavior by printing out typedef properly.

The following example shows forward type and
typedef type can be properly printed in function prototype
with modified test_btf_haskv.c.

  struct t;
  union  u;

  __attribute__((noinline))
  static int test_long_fname_1(struct dummy_tracepoint_args *arg,
                               struct t *p1, union u *p2,
                               __u32 unused)
  ...
  int _dummy_tracepoint(struct dummy_tracepoint_args *arg) {
    return test_long_fname_1(arg, 0, 0, 0);
  }

  $ bpftool p d xlated id 24
  ...
  int test_long_fname_1(struct dummy_tracepoint_args * arg,
                        struct t * p1, union u * p2,
                        __u32 unused)
  ...

Acked-by: Martin KaFai Lau 
Signed-off-by: Yonghong Song 
Signed-off-by: Daniel Borkmann

tools: bpftool: refactor btf_dumper_int_bits()

2018-12-18T00:12:00+00:00

The core dump funcitonality in btf_dumper_int_bits() is
refactored into a separate function btf_dumper_bitfield()
which will be used by the next patch.

Acked-by: Martin KaFai Lau 
Signed-off-by: Yonghong Song 
Signed-off-by: Daniel Borkmann

tools: bpftool: fix -Wmissing declaration warnings

2018-12-15T00:31:49+00:00

Help compiler check arguments for several utility functions used to
print items to the console by adding the "printf" attribute when
declaring those functions.

Also, declare as "static" two functions that are only used in prog.c.

All of them discovered by compiling bpftool with
-Wmissing-format-attribute -Wmissing-declarations.

Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: fix warning on struct bpf_prog_linfo definition

2018-12-15T00:31:49+00:00

The following warning appears when compiling bpftool without BFD
support:

main.h:198:23: warning: 'struct bpf_prog_linfo' declared inside
    parameter list will not be visible outside of this definition or
    declaration
          const struct bpf_prog_linfo *prog_linfo,

Fix it by declaring struct bpf_prog_linfo even in the case BFD is not
supported.

Fixes: b053b439b72a ("bpf: libbpf: bpftool: Print bpf_line_info during prog dump")
Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: add a prog array map update example to documentation

2018-12-15T00:31:49+00:00

Add an example in map documentation to show how to use bpftool in order
to update the references to programs hold by prog array maps.

Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: fix examples in documentation for bpftool prog

2018-12-15T00:31:48+00:00

Bring various fixes to the manual page for "bpftool prog" set of
commands:

- Fix typos ("dum" -> "dump")
- Harmonise indentation and format for command output
- Update date format for program load time
- Add instruction numbers on program dumps
- Fix JSON format for the example program listing

Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: add doc for -m option to bpftool-prog.rst

2018-12-15T00:31:48+00:00

The --mapcompat|-m option has been documented on the main bpftool.rst
page, and on the interactive help. As this option is useful for loading
programs with maps with the "bpftool prog load" command, it should also
appear in the related bpftool-prog.rst documentation page. Let's add it.

Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann