dso-data.c

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// SPDX-License-Identifier: GPL-2.0
#include <dirent.h>
#include <stdlib.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <api/fs/fs.h>
#include "util.h"
#include "machine.h"
#include "symbol.h"
#include "tests.h"
#include "debug.h"

static char *test_file(int size)
{
#define TEMPL "/tmp/perf-test-XXXXXX"
    static char buf_templ[sizeof(TEMPL)];
    char *templ = buf_templ;
    int fd, i;
    unsigned char *buf;

    strcpy(buf_templ, TEMPL);
#undef TEMPL

    fd = mkstemp(templ);
    if (fd < 0) {
        perror("mkstemp failed");
        return NULL;
    }

    buf = malloc(size);
    if (!buf) {
        close(fd);
        return NULL;
    }

    for (i = 0; i < size; i++)
        buf[i] = (unsigned char) ((int) i % 10);

    if (size != write(fd, buf, size))
        templ = NULL;

    free(buf);
    close(fd);
    return templ;
}

#define TEST_FILE_SIZE (DSO__DATA_CACHE_SIZE * 20)

struct test_data_offset {
    off_t offset;
    u8 data[10];
    int size;
};

struct test_data_offset offsets[] = {
    /* Fill first cache page. */
    {
        .offset = 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Read first cache page. */
    {
        .offset = 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Fill cache boundary pages. */
    {
        .offset = DSO__DATA_CACHE_SIZE - DSO__DATA_CACHE_SIZE % 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Read cache boundary pages. */
    {
        .offset = DSO__DATA_CACHE_SIZE - DSO__DATA_CACHE_SIZE % 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Fill final cache page. */
    {
        .offset = TEST_FILE_SIZE - 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Read final cache page. */
    {
        .offset = TEST_FILE_SIZE - 10,
        .data   = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 },
        .size   = 10,
    },
    /* Read final cache page. */
    {
        .offset = TEST_FILE_SIZE - 3,
        .data   = { 7, 8, 9, 0, 0, 0, 0, 0, 0, 0 },
        .size   = 3,
    },
};

/* move it from util/dso.c for compatibility */
static int dso__data_fd(struct dso *dso, struct machine *machine)
{
    int fd = dso__data_get_fd(dso, machine);

    if (fd >= 0)
        dso__data_put_fd(dso);

    return fd;
}

int test__dso_data(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct machine machine;
    struct dso *dso;
    char *file = test_file(TEST_FILE_SIZE);
    size_t i;

    TEST_ASSERT_VAL("No test file", file);

    memset(&machine, 0, sizeof(machine));

    dso = dso__new((const char *)file);

    TEST_ASSERT_VAL("Failed to access to dso",
            dso__data_fd(dso, &machine) >= 0);

    /* Basic 10 bytes tests. */
    for (i = 0; i < ARRAY_SIZE(offsets); i++) {
        struct test_data_offset *data = &offsets[i];
        ssize_t size;
        u8 buf[10];

        memset(buf, 0, 10);
        size = dso__data_read_offset(dso, &machine, data->offset,
                     buf, 10);

        TEST_ASSERT_VAL("Wrong size", size == data->size);
        TEST_ASSERT_VAL("Wrong data", !memcmp(buf, data->data, 10));
    }

    /* Read cross multiple cache pages. */
    {
        ssize_t size;
        int c;
        u8 *buf;

        buf = malloc(TEST_FILE_SIZE);
        TEST_ASSERT_VAL("ENOMEM\n", buf);

        /* First iteration to fill caches, second one to read them. */
        for (c = 0; c < 2; c++) {
            memset(buf, 0, TEST_FILE_SIZE);
            size = dso__data_read_offset(dso, &machine, 10,
                             buf, TEST_FILE_SIZE);

            TEST_ASSERT_VAL("Wrong size",
                size == (TEST_FILE_SIZE - 10));

            for (i = 0; i < (size_t)size; i++)
                TEST_ASSERT_VAL("Wrong data",
                    buf[i] == (i % 10));
        }

        free(buf);
    }

    dso__put(dso);
    unlink(file);
    return 0;
}

static long open_files_cnt(void)
{
    char path[PATH_MAX];
    struct dirent *dent;
    DIR *dir;
    long nr = 0;

    scnprintf(path, PATH_MAX, "%s/self/fd", procfs__mountpoint());
    pr_debug("fd path: %s\n", path);

    dir = opendir(path);
    TEST_ASSERT_VAL("failed to open fd directory", dir);

    while ((dent = readdir(dir)) != NULL) {
        if (!strcmp(dent->d_name, ".") ||
            !strcmp(dent->d_name, ".."))
            continue;

        nr++;
    }

    closedir(dir);
    return nr - 1;
}

static struct dso **dsos;

static int dsos__create(int cnt, int size)
{
    int i;

    dsos = malloc(sizeof(*dsos) * cnt);
    TEST_ASSERT_VAL("failed to alloc dsos array", dsos);

    for (i = 0; i < cnt; i++) {
        char *file;

        file = test_file(size);
        TEST_ASSERT_VAL("failed to get dso file", file);

        dsos[i] = dso__new(file);
        TEST_ASSERT_VAL("failed to get dso", dsos[i]);
    }

    return 0;
}

static void dsos__delete(int cnt)
{
    int i;

    for (i = 0; i < cnt; i++) {
        struct dso *dso = dsos[i];

        unlink(dso->name);
        dso__put(dso);
    }

    free(dsos);
}

static int set_fd_limit(int n)
{
    struct rlimit rlim;

    if (getrlimit(RLIMIT_NOFILE, &rlim))
        return -1;

    pr_debug("file limit %ld, new %d\n", (long) rlim.rlim_cur, n);

    rlim.rlim_cur = n;
    return setrlimit(RLIMIT_NOFILE, &rlim);
}

int test__dso_data_cache(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct machine machine;
    long nr_end, nr = open_files_cnt();
    int dso_cnt, limit, i, fd;

    /* Rest the internal dso open counter limit. */
    reset_fd_limit();

    memset(&machine, 0, sizeof(machine));

    /* set as system limit */
    limit = nr * 4;
    TEST_ASSERT_VAL("failed to set file limit", !set_fd_limit(limit));

    /* and this is now our dso open FDs limit */
    dso_cnt = limit / 2;
    TEST_ASSERT_VAL("failed to create dsos\n",
        !dsos__create(dso_cnt, TEST_FILE_SIZE));

    for (i = 0; i < (dso_cnt - 1); i++) {
        struct dso *dso = dsos[i];

        /*
         * Open dsos via dso__data_fd(), it opens the data
         * file and keep it open (unless open file limit).
         */
        fd = dso__data_fd(dso, &machine);
        TEST_ASSERT_VAL("failed to get fd", fd > 0);

        if (i % 2) {
            #define BUFSIZE 10
            u8 buf[BUFSIZE];
            ssize_t n;

            n = dso__data_read_offset(dso, &machine, 0, buf, BUFSIZE);
            TEST_ASSERT_VAL("failed to read dso", n == BUFSIZE);
        }
    }

    /* verify the first one is already open */
    TEST_ASSERT_VAL("dsos[0] is not open", dsos[0]->data.fd != -1);

    /* open +1 dso to reach the allowed limit */
    fd = dso__data_fd(dsos[i], &machine);
    TEST_ASSERT_VAL("failed to get fd", fd > 0);

    /* should force the first one to be closed */
    TEST_ASSERT_VAL("failed to close dsos[0]", dsos[0]->data.fd == -1);

    /* cleanup everything */
    dsos__delete(dso_cnt);

    /* Make sure we did not leak any file descriptor. */
    nr_end = open_files_cnt();
    pr_debug("nr start %ld, nr stop %ld\n", nr, nr_end);
    TEST_ASSERT_VAL("failed leadking files", nr == nr_end);
    return 0;
}

int test__dso_data_reopen(struct test *test __maybe_unused, int subtest __maybe_unused)
{
    struct machine machine;
    long nr_end, nr = open_files_cnt();
    int fd, fd_extra;

#define dso_0 (dsos[0])
#define dso_1 (dsos[1])
#define dso_2 (dsos[2])

    /* Rest the internal dso open counter limit. */
    reset_fd_limit();

    memset(&machine, 0, sizeof(machine));

    /*
     * Test scenario:
     * - create 3 dso objects
     * - set process file descriptor limit to current
     *   files count + 3
     * - test that the first dso gets closed when we
     *   reach the files count limit
     */

    /* Make sure we are able to open 3 fds anyway */
    TEST_ASSERT_VAL("failed to set file limit",
            !set_fd_limit((nr + 3)));

    TEST_ASSERT_VAL("failed to create dsos\n", !dsos__create(3, TEST_FILE_SIZE));

    /* open dso_0 */
    fd = dso__data_fd(dso_0, &machine);
    TEST_ASSERT_VAL("failed to get fd", fd > 0);

    /* open dso_1 */
    fd = dso__data_fd(dso_1, &machine);
    TEST_ASSERT_VAL("failed to get fd", fd > 0);

    /*
     * open extra file descriptor and we just
     * reached the files count limit
     */
    fd_extra = open("/dev/null", O_RDONLY);
    TEST_ASSERT_VAL("failed to open extra fd", fd_extra > 0);

    /* open dso_2 */
    fd = dso__data_fd(dso_2, &machine);
    TEST_ASSERT_VAL("failed to get fd", fd > 0);

    /*
     * dso_0 should get closed, because we reached
     * the file descriptor limit
     */
    TEST_ASSERT_VAL("failed to close dso_0", dso_0->data.fd == -1);

    /* open dso_0 */
    fd = dso__data_fd(dso_0, &machine);
    TEST_ASSERT_VAL("failed to get fd", fd > 0);

    /*
     * dso_1 should get closed, because we reached
     * the file descriptor limit
     */
    TEST_ASSERT_VAL("failed to close dso_1", dso_1->data.fd == -1);

    /* cleanup everything */
    close(fd_extra);
    dsos__delete(3);

    /* Make sure we did not leak any file descriptor. */
    nr_end = open_files_cnt();
    pr_debug("nr start %ld, nr stop %ld\n", nr, nr_end);
    TEST_ASSERT_VAL("failed leadking files", nr == nr_end);
    return 0;
}