[PATCH v3 4/4] perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace

From: Igor Lubashev <ilubashe@akamai.com>
To: <linux-kernel@vger.kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Jiri Olsa <jolsa@redhat.com>,
	Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	<linux-arm-kernel@lists.infradead.org>,
	James Morris <jmorris@namei.org>,
	Igor Lubashev <ilubashe@akamai.com>
Subject: [PATCH v3 4/4] perf: Use CAP_SYS_ADMIN instead of euid==0 with ftrace
Date: Wed, 7 Aug 2019 10:44:17 -0400	[thread overview]
Message-ID: <bd8763b72ed4d58d0b42d44fbc7eb474d32e53a3.1565188228.git.ilubashe@akamai.com> (raw)
In-Reply-To: <cover.1565188228.git.ilubashe@akamai.com>

Kernel requires CAP_SYS_ADMIN instead of euid==0 to mount debugfs for ftrace.
Make perf do the same.

Signed-off-by: Igor Lubashev <ilubashe@akamai.com>
---
 tools/perf/builtin-ftrace.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index ae1466aa3b26..d09eac8a6d57 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -13,6 +13,7 @@
 #include <signal.h>
 #include <fcntl.h>
 #include <poll.h>
+#include <linux/capability.h>
 
 #include "debug.h"
 #include <subcmd/parse-options.h>
@@ -21,6 +22,7 @@
 #include "target.h"
 #include "cpumap.h"
 #include "thread_map.h"
+#include "util/cap.h"
 #include "util/config.h"
 
 
@@ -281,7 +283,7 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
 		.events = POLLIN,
 	};
 
-	if (geteuid() != 0) {
+	if (!perf_cap__capable(CAP_SYS_ADMIN)) {
 		pr_err("ftrace only works for root!\n");
 		return -1;
 	}
-- 
2.7.4

