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// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <perf/evsel.h>
#include <perf/cpumap.h>
#include <perf/threadmap.h>
#include <linux/list.h>
#include <internal/evsel.h>
#include <linux/zalloc.h>
#include <stdlib.h>
#include <internal/xyarray.h>
#include <internal/cpumap.h>
#include <internal/threadmap.h>
#include <linux/string.h>

void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr)
{
	INIT_LIST_HEAD(&evsel->node);
	evsel->attr = *attr;
}

struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
{
	struct perf_evsel *evsel = zalloc(sizeof(*evsel));

	if (evsel != NULL)
		perf_evsel__init(evsel, attr);

	return evsel;
}

void perf_evsel__delete(struct perf_evsel *evsel)
{
	free(evsel);
}

#define FD(e, x, y) (*(int *) xyarray__entry(e->fd, x, y))

int perf_evsel__alloc_fd(struct perf_evsel *evsel, int ncpus, int nthreads)
{
	evsel->fd = xyarray__new(ncpus, nthreads, sizeof(int));

	if (evsel->fd) {
		int cpu, thread;
		for (cpu = 0; cpu < ncpus; cpu++) {
			for (thread = 0; thread < nthreads; thread++) {
				FD(evsel, cpu, thread) = -1;
			}
		}
	}

	return evsel->fd != NULL ? 0 : -ENOMEM;
}

static int
sys_perf_event_open(struct perf_event_attr *attr,
		    pid_t pid, int cpu, int group_fd,
		    unsigned long flags)
{
	return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags);
}

int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
		     struct perf_thread_map *threads)
{
	int cpu, thread, err = 0;

	if (cpus == NULL) {
		static struct perf_cpu_map *empty_cpu_map;

		if (empty_cpu_map == NULL) {
			empty_cpu_map = perf_cpu_map__dummy_new();
			if (empty_cpu_map == NULL)
				return -ENOMEM;
		}

		cpus = empty_cpu_map;
	}

	if (threads == NULL) {
		static struct perf_thread_map *empty_thread_map;

		if (empty_thread_map == NULL) {
			empty_thread_map = perf_thread_map__new_dummy();
			if (empty_thread_map == NULL)
				return -ENOMEM;
		}

		threads = empty_thread_map;
	}

	if (evsel->fd == NULL &&
	    perf_evsel__alloc_fd(evsel, cpus->nr, threads->nr) < 0)
		return -ENOMEM;

	for (cpu = 0; cpu < cpus->nr; cpu++) {
		for (thread = 0; thread < threads->nr; thread++) {
			int fd;

			fd = sys_perf_event_open(&evsel->attr,
						 threads->map[thread].pid,
						 cpus->map[cpu], -1, 0);

			if (fd < 0)
				return -errno;

			FD(evsel, cpu, thread) = fd;
		}
	}

	return err;
}