// SPDX-License-Identifier: GPL-2.0-only
/*
 * Implementation of get_cpuid().
 *
 * Author: Nikita Shubin <n.shubin@yadro.com>
 */

#include <stdio.h>
#include <stdlib.h>
#include <api/fs/fs.h>
#include <errno.h>
#include "../../util/debug.h"
#include "../../util/header.h"

#define CPUINFO_MVEN    "mvendorid"
#define CPUINFO_MARCH   "marchid"
#define CPUINFO_MIMP    "mimpid"
#define CPUINFO         "/proc/cpuinfo"

static char *_get_field(const char *line)
{
        char *line2, *nl;

        line2 = strrchr(line, ' ');
        if (!line2)
                return NULL;

        line2++;
        nl = strrchr(line, '\n');
        if (!nl)
                return NULL;

        return strndup(line2, nl - line2);
}

static char *_get_cpuid(void)
{
        char *line = NULL;
        char *mvendorid = NULL;
        char *marchid = NULL;
        char *mimpid = NULL;
        char *cpuid = NULL;
        int read;
        size_t line_sz;
        FILE *cpuinfo;

        cpuinfo = fopen(CPUINFO, "r");
        if (cpuinfo == NULL)
                return cpuid;

        while ((read = getline(&line, &line_sz, cpuinfo)) != -1) {
                if (!strncmp(line, CPUINFO_MVEN, strlen(CPUINFO_MVEN))) {
                        mvendorid = _get_field(line);
                        if (!mvendorid)
                                goto free;
                } else if (!strncmp(line, CPUINFO_MARCH, strlen(CPUINFO_MARCH))) {
                        marchid = _get_field(line);
                        if (!marchid)
                                goto free;
                } else if (!strncmp(line, CPUINFO_MIMP, strlen(CPUINFO_MIMP))) {
                        mimpid = _get_field(line);
                        if (!mimpid)
                                goto free;

                        break;
                }
        }

        if (!mvendorid || !marchid || !mimpid)
                goto free;

        if (asprintf(&cpuid, "%s-%s-%s", mvendorid, marchid, mimpid) < 0)
                cpuid = NULL;

free:
        fclose(cpuinfo);
        free(mvendorid);
        free(marchid);
        free(mimpid);

        return cpuid;
}

int get_cpuid(char *buffer, size_t sz, struct perf_cpu cpu __maybe_unused)
{
        char *cpuid = _get_cpuid();
        int ret = 0;

        if (sz < strlen(cpuid)) {
                ret = -EINVAL;
                goto free;
        }

        scnprintf(buffer, sz, "%s", cpuid);
free:
        free(cpuid);
        return ret;
}

char *
get_cpuid_str(struct perf_cpu cpu __maybe_unused)
{
        return _get_cpuid();
}