proc_sys_kernel_random_entropy_avail.c

// SPDX-License-Identifier: GPL-3.0-or-later

#include "plugin_proc.h"

int do_proc_sys_kernel_random_entropy_avail(int update_every, usec_t dt) {
    (void)dt;

    static procfile *ff = NULL;

    if(unlikely(!ff)) {
        char filename[FILENAME_MAX + 1];
        snprintfz(filename, FILENAME_MAX, "%s%s", netdata_configured_host_prefix, "/proc/sys/kernel/random/entropy_avail");
        ff = procfile_open(config_get("plugin:proc:/proc/sys/kernel/random/entropy_avail", "filename to monitor", filename), "", PROCFILE_FLAG_DEFAULT);
        if(unlikely(!ff)) return 1;
    }

    ff = procfile_readall(ff);
    if(unlikely(!ff)) return 0; // we return 0, so that we will retry to open it next time

    unsigned long long entropy = str2ull(procfile_lineword(ff, 0, 0));

    static RRDSET *st = NULL;
    static RRDDIM *rd = NULL;

    if(unlikely(!st)) {
        st = rrdset_create_localhost(
                "system"
                , "entropy"
                , NULL
                , "entropy"
                , NULL
                , "Available Entropy"
                , "entropy"
                , PLUGIN_PROC_NAME
                , "/proc/sys/kernel/random/entropy_avail"
                , NETDATA_CHART_PRIO_SYSTEM_ENTROPY
                , update_every
                , RRDSET_TYPE_LINE
        );

        rd = rrddim_add(st, "entropy", NULL, 1, 1, RRD_ALGORITHM_ABSOLUTE);
    }
    else rrdset_next(st);

    rrddim_set_by_pointer(st, rd, entropy);
    rrdset_done(st);

    return 0;
}