From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Clark Williams <williams@redhat.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
Igor Lubashev <ilubashe@akamai.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Alexey Budankov <alexey.budankov@linux.intel.com>,
James Morris <jmorris@namei.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Suzuki Poulouse <suzuki.poulose@arm.com>,
linux-arm-kernel@lists.infradead.org,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: [PATCH 13/28] perf tools: Add helpers to use capabilities if present
Date: Wed, 14 Aug 2019 15:40:36 -0300 [thread overview]
Message-ID: <20190814184051.3125-14-acme@kernel.org> (raw)
In-Reply-To: <20190814184051.3125-1-acme@kernel.org>
From: Igor Lubashev <ilubashe@akamai.com>
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>
---
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 <stdbool.h>
+#include <sys/capability.h>
+
+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 <stdbool.h>
+#include <linux/capability.h>
+#include <linux/compiler.h>
+
+#ifdef HAVE_LIBCAP_SUPPORT
+
+#include <sys/capability.h>
+
+bool perf_cap__capable(cap_value_t cap);
+
+#else
+
+#include <unistd.h>
+#include <sys/types.h>
+
+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 <string.h>
#include <errno.h>
#include <limits.h>
+#include <linux/capability.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/time64.h>
#include <unistd.h>
+#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)
{
--
2.21.0
next prev parent reply other threads:[~2019-08-14 18:43 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 18:40 [GIT PULL] perf/core improvements and fixes Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 01/28] perf session: Avoid infinite loop when seeing invalid header.size Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 02/28] perf config: Honour $PERF_CONFIG env var to specify alternate .perfconfig Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 03/28] perf config: Document the PERF_CONFIG environment variable Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 04/28] perf test vfs_getname: Disable ~/.perfconfig to get default output Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 05/28] perf tools: Fix paths in include statements Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 06/28] perf vendor events intel: Add Icelake V1.00 event file Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 07/28] perf top: Set display thread COMM to help with debugging Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 08/28] perf hists: Do not link a pair if already linked Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 09/28] perf trace: Fix segmentation fault when access syscall info on arm64 Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 10/28] perf hist: Remove dummy entries when finding real ones Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 11/28] perf top: Collapse and resort all evsels in a group Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 12/28] tools build: Add capability-related feature detection Arnaldo Carvalho de Melo
2019-08-14 18:40 ` Arnaldo Carvalho de Melo [this message]
2019-08-14 18:40 ` [PATCH 14/28] perf tools: Add NO_LIBCAP=1 to the minimal build test Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 15/28] perf tools: Add CAP_SYSLOG define for older systems Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 16/28] perf ftrace: Use CAP_SYS_ADMIN instead of euid==0 Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 17/28] perf ftrace: Improve error message about capability to use ftrace Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 18/28] perf record: Add an option to take an AUX snapshot on exit Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 19/28] perf tools: Add aux_output attribute flag Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 20/28] perf tools: Add itrace option 'o' to synthesize aux-output events Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 21/28] perf intel-pt: Process options for PEBS event synthesis Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 22/28] perf tools: Add aux-output config term Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 23/28] perf intel-pt: Add brief documentation for PEBS via Intel PT Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 24/28] perf evsel: Provide meaningful warning when trying to use 'aux_output' on older kernels Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 25/28] tools: Keep list of tools in alphabetical order Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 26/28] perf.data documentation: Clarify HEADER_SAMPLE_TOPOLOGY format Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 27/28] perf record: Support aarch64 random socket_id assignment Arnaldo Carvalho de Melo
2019-08-14 18:40 ` [PATCH 28/28] perf ui: No need to set ui_browser to 1 twice Arnaldo Carvalho de Melo
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