1 files changed, 57 insertions, 0 deletions

diff --git a/tools/perf/util/cloexec.c b/tools/perf/util/cloexec.c
new file mode 100644
index 000000000000..c5d05ec17220
--- /dev/null
+++ b/tools/perf/util/cloexec.c
@@ -0,0 +1,57 @@
+#include "util.h"
+#include "../perf.h"
+#include "cloexec.h"
+#include "asm/bug.h"
+
+static unsigned long flag = PERF_FLAG_FD_CLOEXEC;
+
+static int perf_flag_probe(void)
+{
+        /* use 'safest' configuration as used in perf_evsel__fallback() */
+        struct perf_event_attr attr = {
+                .type = PERF_COUNT_SW_CPU_CLOCK,
+                .config = PERF_COUNT_SW_CPU_CLOCK,
+        };
+        int fd;
+        int err;
+
+        /* check cloexec flag */
+        fd = sys_perf_event_open(&attr, 0, -1, -1,
+                                 PERF_FLAG_FD_CLOEXEC);
+        err = errno;
+
+        if (fd >= 0) {
+                close(fd);
+                return 1;
+        }
+
+        WARN_ONCE(err != EINVAL,
+                  "perf_event_open(..., PERF_FLAG_FD_CLOEXEC) failed with unexpected error %d (%s)\n",
+                  err, strerror(err));
+
+        /* not supported, confirm error related to PERF_FLAG_FD_CLOEXEC */
+        fd = sys_perf_event_open(&attr, 0, -1, -1, 0);
+        err = errno;
+
+        if (WARN_ONCE(fd < 0,
+                      "perf_event_open(..., 0) failed unexpectedly with error %d (%s)\n",
+                      err, strerror(err)))
+                return -1;
+
+        close(fd);
+
+        return 0;
+}
+
+unsigned long perf_event_open_cloexec_flag(void)
+{
+        static bool probed;
+
+        if (!probed) {
+                if (perf_flag_probe() <= 0)
+                        flag = 0;
+                probed = true;
+        }
+
+        return flag;
+}