From c22e150e3afa6f8db2300bd510e4ac26bbee1bf3 Mon Sep 17 00:00:00 2001 From: Igor Lubashev Date: Wed, 7 Aug 2019 10:44:14 -0400 Subject: 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 "", line 1, in 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 Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: Alexey Budankov Cc: James Morris Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Suzuki Poulouse 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 --- tools/perf/util/Build | 2 ++ tools/perf/util/cap.c | 29 +++++++++++++++++++++++++++++ tools/perf/util/cap.h | 27 +++++++++++++++++++++++++++ tools/perf/util/event.h | 1 + tools/perf/util/python-ext-sources | 1 + tools/perf/util/setup.py | 2 ++ tools/perf/util/util.c | 9 +++++++++ 7 files changed, 71 insertions(+) create mode 100644 tools/perf/util/cap.c create mode 100644 tools/perf/util/cap.h diff --git a/tools/perf/util/Build b/tools/perf/util/Build index 7abf05131889..7cda749059a9 100644 --- a/tools/perf/util/Build +++ b/tools/perf/util/Build @@ -148,6 +148,8 @@ perf-$(CONFIG_ZLIB) += zlib.o perf-$(CONFIG_LZMA) += lzma.o perf-$(CONFIG_ZSTD) += zstd.o +perf-$(CONFIG_LIBCAP) += cap.o + perf-y += demangle-java.o perf-y += demangle-rust.o diff --git a/tools/perf/util/cap.c b/tools/perf/util/cap.c new file mode 100644 index 000000000000..c3ba841bbf37 --- /dev/null +++ b/tools/perf/util/cap.c @@ -0,0 +1,29 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Capability utilities + */ + +#ifdef HAVE_LIBCAP_SUPPORT + +#include "cap.h" +#include +#include + +bool perf_cap__capable(cap_value_t cap) +{ + cap_flag_value_t val; + cap_t caps = cap_get_proc(); + + if (!caps) + return false; + + if (cap_get_flag(caps, cap, CAP_EFFECTIVE, &val) != 0) + val = CAP_CLEAR; + + if (cap_free(caps) != 0) + return false; + + return val == CAP_SET; +} + +#endif /* HAVE_LIBCAP_SUPPORT */ diff --git a/tools/perf/util/cap.h b/tools/perf/util/cap.h new file mode 100644 index 000000000000..10af94e473da --- /dev/null +++ b/tools/perf/util/cap.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __PERF_CAP_H +#define __PERF_CAP_H + +#include +#include +#include + +#ifdef HAVE_LIBCAP_SUPPORT + +#include + +bool perf_cap__capable(cap_value_t cap); + +#else + +#include +#include + +static inline bool perf_cap__capable(int cap __maybe_unused) +{ + return geteuid() == 0; +} + +#endif /* HAVE_LIBCAP_SUPPORT */ + +#endif /* __PERF_CAP_H */ diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h index 70841d115349..0e164e8ae28d 100644 --- a/tools/perf/util/event.h +++ b/tools/perf/util/event.h @@ -851,6 +851,7 @@ void cpu_map_data__synthesize(struct cpu_map_data *data, struct perf_cpu_map *m void event_attr_init(struct perf_event_attr *attr); int perf_event_paranoid(void); +bool perf_event_paranoid_check(int max_level); extern int sysctl_perf_event_max_stack; extern int sysctl_perf_event_max_contexts_per_stack; diff --git a/tools/perf/util/python-ext-sources b/tools/perf/util/python-ext-sources index 235bd9803390..c6dd478956f1 100644 --- a/tools/perf/util/python-ext-sources +++ b/tools/perf/util/python-ext-sources @@ -7,6 +7,7 @@ util/python.c ../lib/ctype.c +util/cap.c util/evlist.c util/evsel.c util/cpumap.c diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py index d48f9cd58964..aa344a163eaf 100644 --- a/tools/perf/util/setup.py +++ b/tools/perf/util/setup.py @@ -59,6 +59,8 @@ ext_sources = list(map(lambda x: '%s/%s' % (src_perf, x) , ext_sources)) extra_libraries = [] if '-DHAVE_LIBNUMA_SUPPORT' in cflags: extra_libraries = [ 'numa' ] +if '-DHAVE_LIBCAP_SUPPORT' in cflags: + extra_libraries += [ 'cap' ] perf = Extension('perf', sources = ext_sources, diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c index 9c3c97697387..6fd130a5d8f2 100644 --- a/tools/perf/util/util.c +++ b/tools/perf/util/util.c @@ -16,10 +16,12 @@ #include #include #include +#include #include #include #include #include +#include "cap.h" #include "strlist.h" #include "string2.h" @@ -403,6 +405,13 @@ int perf_event_paranoid(void) return value; } + +bool perf_event_paranoid_check(int max_level) +{ + return perf_cap__capable(CAP_SYS_ADMIN) || + perf_event_paranoid() <= max_level; +} + static int fetch_ubuntu_kernel_version(unsigned int *puint) { -- cgit v1.2.3-59-g8ed1b