[PATCH 3/7] libperf: Add support for overflow handling of sampling events

[Shunsuke Nakamura <nakamura.shun@fujitsu.com>]

Extend the fields of the opts structure to set up overflow handling
for sampling events. Also, add processing to set signal handlers in
perf_evsel__open_opts.

Signed-off-by: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
---
 tools/lib/perf/Documentation/libperf.txt |  6 +-
 tools/lib/perf/Makefile                  |  1 +
 tools/lib/perf/evsel.c                   | 79 ++++++++++++++++++++++++
 tools/lib/perf/include/perf/evsel.h      |  6 +-
 tools/lib/perf/tests/test-evlist.c       |  1 -
 5 files changed, 90 insertions(+), 3 deletions(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index 6ca91ca94e01..ec93b1c75ebe 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -137,8 +137,12 @@ SYNOPSIS
           size_t sz;
 
           unsigned long open_flags;       /* perf_event_open flags */
+          int flags;                      /* fcntl flags */
+          unsigned int signal;
+          int owner_type;
+          struct sigaction *sig;
   };
-  #define perf_evsel_open_opts__last_field open_flags
+  #define perf_evsel_open_opts__last_field sig
 
   #define LIBPERF_OPTS(TYPE, NAME, ...)
 
diff --git a/tools/lib/perf/Makefile b/tools/lib/perf/Makefile
index 21df023a2103..4c8fae193cf5 100644
--- a/tools/lib/perf/Makefile
+++ b/tools/lib/perf/Makefile
@@ -75,6 +75,7 @@ override CFLAGS += -Werror -Wall
 override CFLAGS += -fPIC
 override CFLAGS += $(INCLUDES)
 override CFLAGS += -fvisibility=hidden
+override CFLAGS += -D_GNU_SOURCE
 
 all:
 
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index 00c0cea43b52..a289f6c44d7c 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -460,6 +460,79 @@ void perf_counts_values__scale(struct perf_counts_values *count,
 		*pscaled = scaled;
 }
 
+static int perf_evsel__run_fcntl(struct perf_evsel *evsel,
+				 unsigned int cmd, unsigned long arg,
+				 int cpu_map_idx)
+{
+	int thread;
+
+	for (thread = 0; thread < xyarray__max_y(evsel->fd); thread++) {
+		int err;
+		int *fd = FD(evsel, cpu_map_idx, thread);
+
+		if (!fd || *fd < 0)
+			return -1;
+
+		err = fcntl(*fd, cmd, arg);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int perf_evsel__set_signal_handler(struct perf_evsel *evsel,
+					  struct perf_evsel_open_opts *opts)
+{
+	unsigned int flags;
+	unsigned int signal;
+	struct f_owner_ex owner;
+	struct sigaction *sig;
+	int cpu_map_idx;
+	int err = 0;
+
+	flags = OPTS_GET(opts, flags, (O_RDWR | O_NONBLOCK | O_ASYNC));
+	signal = OPTS_GET(opts, signal, SIGIO);
+	owner.type = OPTS_GET(opts, owner_type, F_OWNER_PID);
+	sig = OPTS_GET(opts, sig, NULL);
+
+	if (flags == 0 && signal == 0 && !owner.type == 0 && sig == 0)
+		return err;
+
+	err = sigaction(signal, sig, NULL);
+	if (err)
+		return err;
+
+	switch (owner.type) {
+	case F_OWNER_PID:
+		owner.pid = getpid();
+		break;
+	case F_OWNER_TID:
+		owner.pid = syscall(SYS_gettid);
+		break;
+	case F_OWNER_PGRP:
+	default:
+		return -1;
+	}
+
+	for (cpu_map_idx = 0; cpu_map_idx < xyarray__max_x(evsel->fd); cpu_map_idx++) {
+		err = perf_evsel__run_fcntl(evsel, F_SETFL, flags, cpu_map_idx);
+		if (err)
+			return err;
+
+		err = perf_evsel__run_fcntl(evsel, F_SETSIG, signal, cpu_map_idx);
+		if (err)
+			return err;
+
+		err = perf_evsel__run_fcntl(evsel, F_SETOWN_EX,
+					    (unsigned long)&owner, cpu_map_idx);
+		if (err)
+			return err;
+	}
+
+	return err;
+}
+
 int perf_evsel__open_opts(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
 			  struct perf_thread_map *threads,
 			  struct perf_evsel_open_opts *opts)
@@ -474,6 +547,12 @@ int perf_evsel__open_opts(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
 	evsel->open_flags = OPTS_GET(opts, open_flags, 0);
 
 	err = perf_evsel__open(evsel, cpus, threads);
+	if (err)
+		return err;
+
+	err = perf_evsel__set_signal_handler(evsel, opts);
+	if (err)
+		return err;
 
 	return err;
 }
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 1140df4d2578..50662babfe97 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -29,8 +29,12 @@ struct perf_evsel_open_opts {
 	size_t sz;
 
 	unsigned long open_flags;	/* perf_event_open flags */
+	int flags;			/* fcntl flags */
+	unsigned int signal;
+	int owner_type;
+	struct sigaction *sig;
 };
-#define perf_evsel_open_opts__last_field open_flags
+#define perf_evsel_open_opts__last_field sig
 
 #define LIBPERF_OPTS(TYPE, NAME, ...)			\
 	struct TYPE NAME = ({				\
diff --git a/tools/lib/perf/tests/test-evlist.c b/tools/lib/perf/tests/test-evlist.c
index ed616fc19b4f..d8f9493cd4d1 100644
--- a/tools/lib/perf/tests/test-evlist.c
+++ b/tools/lib/perf/tests/test-evlist.c
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: GPL-2.0
-#define _GNU_SOURCE // needed for sched.h to get sched_[gs]etaffinity and CPU_(ZERO,SET)
 #include <inttypes.h>
 #include <sched.h>
 #include <stdio.h>
-- 
2.25.1