linux-toradex.git/tools/bpf, branch v4.20-rc6

tools: bpftool: fix a bitfield pretty print issue

2018-11-29T00:40:02+00:00

Commit b12d6ec09730 ("bpf: btf: add btf print functionality")
added btf pretty print functionality to bpftool.
There is a problem though in printing a bitfield whose type
has modifiers.

For example, for a type like
  typedef int ___int;
  struct tmp_t {
          int a:3;
          ___int b:3;
  };
Suppose we have a map
  struct bpf_map_def SEC("maps") tmpmap = {
          .type = BPF_MAP_TYPE_HASH,
          .key_size = sizeof(__u32),
          .value_size = sizeof(struct tmp_t),
          .max_entries = 1,
  };
and the hash table is populated with one element with
key 0 and value (.a = 1 and .b = 2).

In BTF, the struct member "b" will have a type "typedef" which
points to an int type. The current implementation does not
pass the bit offset during transition from typedef to int type,
hence incorrectly print the value as
  $ bpftool m d id 79
  [{
          "key": 0,
          "value": {
              "a": 0x1,
              "b": 0x1
          }
      }
  ]

This patch fixed the issue by carrying bit_offset along the type
chain during bit_field print. The correct result can be printed as
  $ bpftool m d id 76
  [{
          "key": 0,
          "value": {
              "a": 0x1,
              "b": 0x2
          }
      }
  ]

The kernel pretty print is implemented correctly and does not
have this issue.

Fixes: b12d6ec09730 ("bpf: btf: add btf print functionality")
Signed-off-by: Yonghong Song 
Acked-by: Song Liu 
Signed-off-by: Alexei Starovoitov

tools: bpftool: fix potential NULL pointer dereference in do_load

2018-11-21T23:45:51+00:00

This patch fixes a possible null pointer dereference in
do_load, detected by the semantic patch deref_null.cocci,
with the following warning:

./tools/bpf/bpftool/prog.c:1021:23-25: ERROR: map_replace is NULL but dereferenced.

The following code has potential null pointer references:
881             map_replace = reallocarray(map_replace, old_map_fds + 1,
882                                        sizeof(*map_replace));
883             if (!map_replace) {
884                     p_err("mem alloc failed");
885                     goto err_free_reuse_maps;
886             }

...
1019 err_free_reuse_maps:
1020         for (i = 0; i < old_map_fds; i++)
1021                 close(map_replace[i].fd);
1022         free(map_replace);

Fixes: 3ff5a4dc5d89 ("tools: bpftool: allow reuse of maps with bpftool prog load")
Co-developed-by: Wen Yang 
Signed-off-by: Wen Yang 
Signed-off-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: update references to other man pages in documentation

2018-11-09T07:20:52+00:00

Update references to other bpftool man pages at the bottom of each
manual page. Also reference the "bpf(2)" and "bpf-helpers(7)" man pages.

References are sorted by number of man section, then by
"prog-and-map-go-first", the other pages in alphabetical order.

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

tools: bpftool: pass an argument to silence open_obj_pinned()

2018-11-09T07:20:52+00:00

Function open_obj_pinned() prints error messages when it fails to open a
link in the BPF virtual file system. However, in some occasions it is
not desirable to print an error, for example when we parse all links
under the bpffs root, and the error is due to some paths actually being
symbolic links.

Example output:

    # ls -l /sys/fs/bpf/
    lrwxrwxrwx 1 root root 0 Oct 18 19:00 ip -> /sys/fs/bpf/tc/
    drwx------ 3 root root 0 Oct 18 19:00 tc
    lrwxrwxrwx 1 root root 0 Oct 18 19:00 xdp -> /sys/fs/bpf/tc/

    # bpftool --bpffs prog show
    Error: bpf obj get (/sys/fs/bpf): Permission denied
    Error: bpf obj get (/sys/fs/bpf): Permission denied

    # strace -e bpf bpftool --bpffs prog show
    bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/ip", bpf_fd=0}, 72) = -1 EACCES (Permission denied)
    Error: bpf obj get (/sys/fs/bpf): Permission denied
    bpf(BPF_OBJ_GET, {pathname="/sys/fs/bpf/xdp", bpf_fd=0}, 72) = -1 EACCES (Permission denied)
    Error: bpf obj get (/sys/fs/bpf): Permission denied
    ...

To fix it, pass a bool as a second argument to the function, and prevent
it from printing an error when the argument is set to true.

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

tools: bpftool: fix plain output and doc for --bpffs option

2018-11-09T07:20:52+00:00

Edit the documentation of the -f|--bpffs option to make it explicit that
it dumps paths of pinned programs when bpftool is used to list the
programs only, so that users do not believe they will see the name of
the newly pinned program with "bpftool prog pin" or "bpftool prog load".

Also fix the plain output: do not add a blank line after each program
block, in order to remain consistent with what bpftool does when the
option is not passed.

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

tools: bpftool: prevent infinite loop in get_fdinfo()

2018-11-09T07:20:52+00:00

Function getline() returns -1 on failure to read a line, thus creating
an infinite loop in get_fdinfo() if the key is not found. Fix it by
calling the function only as long as we get a strictly positive return
value.

Found by copying the code for a key which is not always present...

Fixes: 71bb428fe2c1 ("tools: bpf: add bpftool")
Signed-off-by: Quentin Monnet 
Reviewed-by: Jakub Kicinski 
Signed-off-by: Daniel Borkmann

tools: bpftool: fix completion for "bpftool map update"

2018-10-21T18:45:14+00:00

When trying to complete "bpftool map update" commands, the call to
printf would print an error message that would show on the command line
if no map is found to complete the command line.

Fix it by making sure we have map ids to complete the line with, before
we try to print something.

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

tools: bpftool: print nb of cmds to stdout (not stderr) for batch mode

2018-10-21T18:45:14+00:00

When batch mode is used and all commands succeeds, bpftool prints the
number of commands processed to stderr. There is no particular reason to
use stderr for this, we could as well use stdout. It would avoid getting
unnecessary output on stderr if the standard ouptut is redirected, for
example.

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

tools: bpftool: document restriction on '.' in names to pin in bpffs

2018-10-21T18:45:14+00:00

Names used to pin eBPF programs and maps under the eBPF virtual file
system cannot contain a dot character, which is reserved for future
extensions of this file system.

Document this in bpftool man pages to avoid users getting confused if
pinning fails because of a dot.

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

bpf, libbpf: simplify and cleanup perf ring buffer walk

2018-10-21T06:13:32+00:00

Simplify bpf_perf_event_read_simple() a bit and fix up some minor
things along the way: the return code in the header is not of type
int but enum bpf_perf_event_ret instead. Once callback indicated
to break the loop walking event data, it also needs to be consumed
in data_tail since it has been processed already.

Moreover, bpf_perf_event_print_t callback should avoid void * as
we actually get a pointer to struct perf_event_header and thus
applications can make use of container_of() to have type checks.
The walk also doesn't have to use modulo op since the ring size is
required to be power of two.

Signed-off-by: Daniel Borkmann 
Signed-off-by: Alexei Starovoitov