Igor Lubashev c22e150e3a perf tools: Add helpers to use capabilities if present
Add utilities to help checking capabilities of the running procss.  Make
perf link with libcap, if it is available. If no libcap-dev[el],
fallback to the geteuid() == 0 test used before.

Committer notes:

  $ perf test python
  18: 'import perf' in python                               : FAILED!
  $ perf test -v python
  Couldn't bump rlimit(MEMLOCK), failures may take place when creating BPF maps, etc
  18: 'import perf' in python                               :
  --- start ---
  test child forked, pid 23288
  Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
  ImportError: /tmp/build/perf/python/perf.so: undefined symbol: cap_get_flag
  test child finished with -1
  ---- end ----
  'import perf' in python: FAILED!
  $

This happens because differently from the perf binary generated with
this patch applied:

  $ ldd /tmp/build/perf/perf | grep libcap
  	libcap.so.2 => /lib64/libcap.so.2 (0x00007f724a4ef000)
  $

The python binding isn't linking with libcap:

  $ ldd /tmp/build/perf/python/perf.so | grep libcap
  $

So add 'cap' to the 'extra_libraries' variable in
tools/perf/util/setup.py, and rebuild:

  $ perf test python
  18: 'import perf' in python                               : Ok
  $

If we explicitely disable libcap it also continues to work:

  $ make NO_LIBCAP=1 -C tools/perf O=/tmp/build/perf install-bin
    $ ldd /tmp/build/perf/perf | grep libcap
  $ ldd /tmp/build/perf/python/perf.so | grep libcap
  $ perf test python
  18: 'import perf' in python                               : Ok
  $

Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
[ split from a larger patch ]
Link: http://lkml.kernel.org/r/8a1e76cf5c7c9796d0d4d240fbaa85305298aafa.1565188228.git.ilubashe@akamai.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2019-08-14 10:48:39 -03:00
2019-08-10 16:31:47 -07:00
2019-07-11 15:40:06 -07:00
2019-08-10 16:31:47 -07:00
2019-08-11 13:15:10 -07:00
2019-08-02 18:40:49 -07:00
2019-08-09 09:21:27 -07:00
2019-08-09 16:53:50 +02:00
2019-07-22 14:57:50 +01:00
2019-07-19 12:22:04 -07:00
2019-03-10 17:48:21 -07:00
2019-08-10 12:24:20 -07:00
2019-08-11 13:26:41 -07:00

Linux kernel
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