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Subject[PATCH 1/3] perf: Add capability-related utilities
Date
Add utilities to help checking capabilities of the running process.
Make perf link with libcap.

Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
---
tools/perf/Makefile.config | 2 +-
tools/perf/util/Build | 1 +
tools/perf/util/cap.c | 24 ++++++++++++++++++++++++
tools/perf/util/cap.h | 10 ++++++++++
tools/perf/util/event.h | 1 +
tools/perf/util/python-ext-sources | 1 +
tools/perf/util/util.c | 9 +++++++++
7 files changed, 47 insertions(+), 1 deletion(-)
create mode 100644 tools/perf/util/cap.c
create mode 100644 tools/perf/util/cap.h

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 85fbcd265351..21470a50ed39 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -259,7 +259,7 @@ CXXFLAGS += -Wno-strict-aliasing
# adding assembler files missing the .GNU-stack linker note.
LDFLAGS += -Wl,-z,noexecstack

-EXTLIBS = -lpthread -lrt -lm -ldl
+EXTLIBS = -lpthread -lrt -lm -ldl -lcap

ifeq ($(FEATURES_DUMP),)
include $(srctree)/tools/build/Makefile.feature
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 6d5bbc8b589b..9cc6e9b34ebd 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -1,6 +1,7 @@
perf-y += annotate.o
perf-y += block-range.o
perf-y += build-id.o
+perf-y += cap.o
perf-y += config.o
perf-y += ctype.o
perf-y += db-export.o
diff --git a/tools/perf/util/cap.c b/tools/perf/util/cap.c
new file mode 100644
index 000000000000..c42ea32663cf
--- /dev/null
+++ b/tools/perf/util/cap.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Capability utilities
+ */
+#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;
+}
diff --git a/tools/perf/util/cap.h b/tools/perf/util/cap.h
new file mode 100644
index 000000000000..5521de78b228
--- /dev/null
+++ b/tools/perf/util/cap.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_CAP_H
+#define __PERF_CAP_H
+
+#include <stdbool.h>
+#include <sys/capability.h>
+
+bool perf_cap__capable(cap_value_t cap);
+
+#endif /* __PERF_CAP_H */
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 9e999550f247..013d9e28fcac 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -849,6 +849,7 @@ void cpu_map_data__synthesize(struct cpu_map_data *data, struct cpu_map *map,
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 7aa0ea64544e..4545eaf018b5 100644
--- a/tools/perf/util/python-ext-sources
+++ b/tools/perf/util/python-ext-sources
@@ -6,6 +6,7 @@
#

util/python.c
+util/cap.c
util/ctype.c
util/evlist.c
util/evsel.c
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index d388f80d8703..cde538ec727d 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"

@@ -456,6 +458,13 @@ 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)
{
--
2.7.4
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