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tools build: Add capability-related feature detection

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Add utilities to help checking capabilities of the running procss.  Make
perf link with libcap, if it is available. If no libcap-dev[el], assume
no capabilities.

Committer testing:

  $ make O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j8' parallel build

  Auto-detecting system features:
  <SNIP>
  ...                        libbfd: [ on  ]
  ...                        libcap: [ OFF ]
  ...                        libelf: [ on  ]
  <SNIP>
  Makefile.config:833: No libcap found, disables capability support, please install libcap-devel/libcap-dev
  <SNIP>
  $ grep libcap /tmp/build/perf/FEATURE-DUMP
  feature-libcap=0
  $ cat /tmp/build/perf/feature/test-libcap.make.output
  test-libcap.c:2:10: fatal error: sys/capability.h: No such file or directory
      2 | #include <sys/capability.h>
        |          ^~~~~~~~~~~~~~~~~~
  compilation terminated.
  $

Now install libcap-devel and try again:

  $ make O=/tmp/build/perf -C tools/perf install-bin
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j8' parallel build
  Warning: Kernel ABI header at 'tools/include/linux/bits.h' differs from latest version at 'include/linux/bits.h'
  diff -u tools/include/linux/bits.h include/linux/bits.h
  Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
  diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h

  Auto-detecting system features:
  <SNIP>
  ...                        libbfd: [ on  ]
  ...                        libcap: [ on  ]
  ...                        libelf: [ on  ]
  <SNIP>>
    CC       /tmp/build/perf/jvmti/libjvmti.o
  <SNIP>>
  $ grep libcap /tmp/build/perf/FEATURE-DUMP
  feature-libcap=1
  $ cat /tmp/build/perf/feature/test-libcap.make.output
  $ ldd /tmp/build/perf/feature/test-libcap.make.bin
  ldd: /tmp/build/perf/feature/test-libcap.make.bin: No such file or directory
  $ ldd /tmp/build/perf/feature/test-libcap.bin
  	linux-vdso.so.1 (0x00007ffc35bfe000)
  	libcap.so.2 => /lib64/libcap.so.2 (0x00007ff9c62ff000)
  	libc.so.6 => /lib64/libc.so.6 (0x00007ff9c6139000)
  	/lib64/ld-linux-x86-64.so.2 (0x00007ff9c6326000)
  $

Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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>
[ 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>
This commit is contained in:
Igor Lubashev 2019-08-07 10:44:14 -04:00 committed by Arnaldo Carvalho de Melo
parent 40d81772da
commit 74d5f3d06f
5 changed files with 39 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

2
tools/build/Makefile.feature
View file

@ -42,6 +42,7 @@ FEATURE_TESTS_BASIC := \
gtk2-infobar \
libaudit \
libbfd \
libcap \
libelf \
libelf-getphdrnum \
libelf-gelf_getnote \
@ -110,6 +111,7 @@ FEATURE_DISPLAY ?= \
gtk2 \
libaudit \
libbfd \
libcap \
libelf \
libnuma \
numa_num_possible_cpus \

4
tools/build/feature/Makefile
View file

@ -20,6 +20,7 @@ FILES= \
test-libbfd-liberty.bin \
test-libbfd-liberty-z.bin \
test-cplus-demangle.bin \
test-libcap.bin \
test-libelf.bin \
test-libelf-getphdrnum.bin \
test-libelf-gelf_getnote.bin \
@ -105,6 +106,9 @@ $(OUTPUT)test-fortify-source.bin:
$(OUTPUT)test-bionic.bin:
$(BUILD)
$(OUTPUT)test-libcap.bin:
$(BUILD) -lcap
$(OUTPUT)test-libelf.bin:
$(BUILD) -lelf

20
tools/build/feature/test-libcap.c Normal file
View file

@ -0,0 +1,20 @@
// SPDX-License-Identifier: GPL-2.0
#include <sys/capability.h>
#include <linux/capability.h>
int main(void)
{
cap_flag_value_t val;
cap_t caps = cap_get_proc();
if (!caps)
return 1;
if (cap_get_flag(caps, CAP_SYS_ADMIN, CAP_EFFECTIVE, &val) != 0)
return 1;
if (cap_free(caps) != 0)
return 1;
return 0;
}

11
tools/perf/Makefile.config
View file

@ -824,6 +824,17 @@ ifndef NO_LIBZSTD
endif
endif
ifndef NO_LIBCAP
ifeq ($(feature-libcap), 1)
CFLAGS += -DHAVE_LIBCAP_SUPPORT
EXTLIBS += -lcap
$(call detected,CONFIG_LIBCAP)
else
msg := $(warning No libcap found, disables capability support, please install libcap-devel/libcap-dev);
NO_LIBCAP := 1
endif
endif
ifndef NO_BACKTRACE
ifeq ($(feature-backtrace), 1)
CFLAGS += -DHAVE_BACKTRACE_SUPPORT

2
tools/perf/Makefile.perf
View file

@ -88,6 +88,8 @@ include ../scripts/utilities.mak
#
# Define NO_LIBBPF if you do not want BPF support
#
# Define NO_LIBCAP if you do not want process capabilities considered by perf
#
# Define NO_SDT if you do not want to define SDT event in perf tools,
# note that it doesn't disable SDT scanning support.
#