keep-tracking.c

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// SPDX-License-Identifier: GPL-2.0
#include <linux/types.h>
#include <unistd.h>
#include <sys/prctl.h>

#include "parse-events.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "cpumap.h"
#include "tests.h"

#define CHECK__(x) {                \
    while ((x) < 0) {           \
        pr_debug(#x " failed!\n");  \
        goto out_err;           \
    }                   \
}

#define CHECK_NOT_NULL__(x) {           \
    while ((x) == NULL) {           \
        pr_debug(#x " failed!\n");  \
        goto out_err;           \
    }                   \
}

static int find_comm(struct perf_evlist *evlist, const char *comm)
{
    union perf_event *event;
    struct perf_mmap *md;
    int i, found;

    found = 0;
    for (i = 0; i < evlist->nr_mmaps; i++) {
        md = &evlist->mmap[i];
        if (perf_mmap__read_init(md) < 0)
            continue;
        while ((event = perf_mmap__read_event(md)) != NULL) {
            if (event->header.type == PERF_RECORD_COMM &&
                (pid_t)event->comm.pid == getpid() &&
                (pid_t)event->comm.tid == getpid() &&
                strcmp(event->comm.comm, comm) == 0)
                found += 1;
            perf_mmap__consume(md);
        }
        perf_mmap__read_done(md);
    }
    return found;
}

int test__keep_tracking(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct record_opts opts = {
        .mmap_pages      = UINT_MAX,
        .user_freq       = UINT_MAX,
        .user_interval       = ULLONG_MAX,
        .target          = {
            .uses_mmap   = true,
        },
    };
    struct thread_map *threads = NULL;
    struct cpu_map *cpus = NULL;
    struct perf_evlist *evlist = NULL;
    struct perf_evsel *evsel = NULL;
    int found, err = -1;
    const char *comm;

    threads = thread_map__new(-1, getpid(), UINT_MAX);
    CHECK_NOT_NULL__(threads);

    cpus = cpu_map__new(NULL);
    CHECK_NOT_NULL__(cpus);

    evlist = perf_evlist__new();
    CHECK_NOT_NULL__(evlist);

    perf_evlist__set_maps(evlist, cpus, threads);

    CHECK__(parse_events(evlist, "dummy:u", NULL));
    CHECK__(parse_events(evlist, "cycles:u", NULL));

    perf_evlist__config(evlist, &opts, NULL);

    evsel = perf_evlist__first(evlist);

    evsel->attr.comm = 1;
    evsel->attr.disabled = 1;
    evsel->attr.enable_on_exec = 0;

    if (perf_evlist__open(evlist) < 0) {
        pr_debug("Unable to open dummy and cycles event\n");
        err = TEST_SKIP;
        goto out_err;
    }

    CHECK__(perf_evlist__mmap(evlist, UINT_MAX));

    /*
     * First, test that a 'comm' event can be found when the event is
     * enabled.
     */

    perf_evlist__enable(evlist);

    comm = "Test COMM 1";
    CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));

    perf_evlist__disable(evlist);

    found = find_comm(evlist, comm);
    if (found != 1) {
        pr_debug("First time, failed to find tracking event.\n");
        goto out_err;
    }

    /*
     * Secondly, test that a 'comm' event can be found when the event is
     * disabled with the dummy event still enabled.
     */

    perf_evlist__enable(evlist);

    evsel = perf_evlist__last(evlist);

    CHECK__(perf_evsel__disable(evsel));

    comm = "Test COMM 2";
    CHECK__(prctl(PR_SET_NAME, (unsigned long)comm, 0, 0, 0));

    perf_evlist__disable(evlist);

    found = find_comm(evlist, comm);
    if (found != 1) {
        pr_debug("Seconf time, failed to find tracking event.\n");
        goto out_err;
    }

    err = 0;

out_err:
    if (evlist) {
        perf_evlist__disable(evlist);
        perf_evlist__delete(evlist);
    } else {
        cpu_map__put(cpus);
        thread_map__put(threads);
    }

    return err;
}