// SPDX-License-Identifier: GPL-2.0-only
/*
 * Implementation of get_cpuid().
 *
 * Author: Nikita Shubin <n.shubin@yadro.com>
 *         Bibo Mao <maobibo@loongson.cn>
 *         Huacai Chen <chenhuacai@loongson.cn>
 */

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

/*
 * Output example from /proc/cpuinfo
 *   CPU Family              : Loongson-64bit
 *   Model Name              : Loongson-3C5000
 *   CPU Revision            : 0x10
 *   FPU Revision            : 0x01
 */
#define CPUINFO_MODEL   "Model Name"
#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)
{
        unsigned long line_sz;
        char *line, *model, *cpuid;
        FILE *file;

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

        line = model = cpuid = NULL;
        while (getline(&line, &line_sz, file) != -1) {
                if (strncmp(line, CPUINFO_MODEL, strlen(CPUINFO_MODEL)))
                        continue;

                model = _get_field(line);
                if (!model)
                        goto out_free;
                break;
        }

        if (model && (asprintf(&cpuid, "%s", model) < 0))
                cpuid = NULL;

out_free:
        fclose(file);
        free(model);
        return cpuid;
}

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

        if (!cpuid)
                return EINVAL;

        if (sz < strlen(cpuid)) {
                ret = ENOBUFS;
                goto out_free;
        }

        scnprintf(buffer, sz, "%s", cpuid);

out_free:
        free(cpuid);
        return ret;
}

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