[PATCH v2 3/8] libperf: Introduce perf_{evsel, evlist}__open_opt with extensible struct opts

[Charlie Jenkins]

From: Shunsuke Nakamura <nakamura.shun@xxxxxxxxxxx>

Introduce perf_{evsel, evlist}__open_opt with extensible structure opts.
The mechanism of the extensible structure opts imitates
tools/lib/bpf/libbpf.h. Currently, only open_flags is supported for the
opts structure.

Signed-off-by: Shunsuke Nakamura <nakamura.shun@xxxxxxxxxxx>
Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
---
 tools/lib/perf/Documentation/libperf.txt | 10 ++++++++++
 tools/lib/perf/evlist.c                  | 20 ++++++++++++++++++++
 tools/lib/perf/evsel.c                   | 26 +++++++++++++++++++++++++-
 tools/lib/perf/include/perf/evlist.h     |  3 +++
 tools/lib/perf/include/perf/evsel.h      | 23 +++++++++++++++++++++++
 tools/lib/perf/libperf.map               |  2 ++
 6 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index fcfb9499ef9c..83827b94617a 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -132,6 +132,16 @@ SYNOPSIS
           };
   };
 
+  struct perf_evsel_open_opts {
+          /* size of this struct, for forward/backward compatibility */
+          size_t sz;
+
+          unsigned long open_flags;       /* perf_event_open flags */
+  };
+  #define perf_evsel_open_opts__last_field open_flags
+
+  #define LIBPERF_OPTS(TYPE, NAME, ...)
+
   struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
   void perf_evsel__delete(struct perf_evsel *evsel);
   int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index c6d67fc9e57e..7aa62f90f13b 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -753,3 +753,23 @@ void perf_evlist__go_system_wide(struct perf_evlist *evlist, struct perf_evsel *
 			__perf_evlist__propagate_maps(evlist, evsel);
 	}
 }
+
+int perf_evlist__open_opts(struct perf_evlist *evlist,
+			   struct perf_evsel_open_opts *opts)
+{
+	struct perf_evsel *evsel;
+	int err;
+
+	perf_evlist__for_each_entry(evlist, evsel) {
+		err = perf_evsel__open_opts(evsel, evsel->cpus,
+					    evsel->threads, opts);
+		if (err < 0)
+			goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	perf_evlist__close(evlist);
+	return err;
+}
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index c07160953224..96ecf3e5c8b4 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -16,8 +16,13 @@
 #include <internal/lib.h>
 #include <linux/string.h>
 #include <sys/ioctl.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/types.h>
 #include <sys/mman.h>
 #include <asm/bug.h>
+#include <tools/opts.h>
+#include "internal.h"
 
 void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
 		      int idx)
@@ -26,6 +31,7 @@ void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
 	evsel->attr = *attr;
 	evsel->idx  = idx;
 	evsel->leader = evsel;
+	evsel->open_flags = 0;
 }
 
 struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
@@ -160,7 +166,7 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
 
 			fd = sys_perf_event_open(&evsel->attr,
 						 threads->map[thread].pid,
-						 cpu, group_fd, 0);
+						 cpu, group_fd, evsel->open_flags);
 
 			if (fd < 0) {
 				err = -errno;
@@ -555,3 +561,21 @@ void perf_counts_values__scale(struct perf_counts_values *count,
 	if (pscaled)
 		*pscaled = scaled;
 }
+
+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)
+{
+	int err = 0;
+
+	if (!OPTS_VALID(opts, perf_evsel_open_opts)) {
+		err = -EINVAL;
+		return err;
+	}
+
+	evsel->open_flags = OPTS_GET(opts, open_flags, 0);
+
+	err = perf_evsel__open(evsel, cpus, threads);
+
+	return err;
+}
diff --git a/tools/lib/perf/include/perf/evlist.h b/tools/lib/perf/include/perf/evlist.h
index e894b770779e..37ac44364d22 100644
--- a/tools/lib/perf/include/perf/evlist.h
+++ b/tools/lib/perf/include/perf/evlist.h
@@ -9,6 +9,7 @@ struct perf_evlist;
 struct perf_evsel;
 struct perf_cpu_map;
 struct perf_thread_map;
+struct perf_evsel_open_opts;
 
 LIBPERF_API void perf_evlist__add(struct perf_evlist *evlist,
 				  struct perf_evsel *evsel);
@@ -48,4 +49,6 @@ LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
 
 LIBPERF_API void perf_evlist__set_leader(struct perf_evlist *evlist);
 LIBPERF_API int perf_evlist__nr_groups(struct perf_evlist *evlist);
+LIBPERF_API int perf_evlist__open_opts(struct perf_evlist *evlist,
+				       struct perf_evsel_open_opts *opts);
 #endif /* __LIBPERF_EVLIST_H */
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 6f92204075c2..8eb3927f3cd0 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -5,6 +5,7 @@
 #include <stdint.h>
 #include <perf/core.h>
 #include <stdbool.h>
+#include <signal.h>
 #include <linux/types.h>
 
 struct perf_evsel;
@@ -25,6 +26,24 @@ struct perf_counts_values {
 	};
 };
 
+struct perf_evsel_open_opts {
+	/* size of this struct, for forward/backward compatibility */
+	size_t sz;
+
+	unsigned long open_flags;	/* perf_event_open flags */
+};
+
+#define perf_evsel_open_opts__last_field open_flags
+
+#define LIBPERF_OPTS(TYPE, NAME, ...)			\
+	struct TYPE NAME = ({				\
+		memset(&NAME, 0, sizeof(struct TYPE));	\
+		(struct TYPE) {				\
+			.sz = sizeof(struct TYPE),	\
+			__VA_ARGS__			\
+		};					\
+	})
+
 LIBPERF_API struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
 LIBPERF_API void perf_evsel__delete(struct perf_evsel *evsel);
 LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
@@ -46,5 +65,9 @@ LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel
 LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
 LIBPERF_API void perf_counts_values__scale(struct perf_counts_values *count,
 					   bool scale, __s8 *pscaled);
+LIBPERF_API 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);
 
 #endif /* __LIBPERF_EVSEL_H */
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 2aa79b696032..84fed76621cb 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -29,6 +29,7 @@ LIBPERF_0.0.1 {
 		perf_evsel__enable;
 		perf_evsel__disable;
 		perf_evsel__open;
+		perf_evsel__open_opts;
 		perf_evsel__close;
 		perf_evsel__mmap;
 		perf_evsel__munmap;
@@ -40,6 +41,7 @@ LIBPERF_0.0.1 {
 		perf_evlist__new;
 		perf_evlist__delete;
 		perf_evlist__open;
+		perf_evlist__open_opts;
 		perf_evlist__close;
 		perf_evlist__enable;
 		perf_evlist__disable;

-- 
2.44.0