/*
 * Copyright (C) 2013 Red Hat, Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Authors: Peter Schiffer <pschiffe@redhat.com>
 */

#include "sysfs.h"


/*
 * Read unsigned value from file.
 * @param path of file
 * @paratm result
 * @return 0 if success, negative value otherwise
 */
short path_get_unsigned(const char *path, unsigned *result)
{
    short ret = -1;
    unsigned buffer_size = 0;
    char **buffer = NULL;

    if (read_file(path, &buffer, &buffer_size) != 0 || buffer_size < 1) {
        ret = -2;
        goto done;
    }
    if (sscanf(buffer[0], "%u", result) != 1) {
        warn("Failed to parse file: \"%s\"; Error: %s",
                path, strerror(errno));
        ret = -3;
        goto done;
    }

    ret = 0;

done:
    free_2d_buffer(&buffer, &buffer_size);

    if (ret != 0) {
        *result = 0;
    }

    return ret;
}

/*
 * Read string value from file.
 * @param path of file
 * @paratm result
 * @return 0 if success, negative value otherwise
 */
short path_get_string(const char *path, char **result)
{
    short ret = -1;
    unsigned buffer_size = 0;
    char **buffer = NULL;

    if (read_file(path, &buffer, &buffer_size) != 0 || buffer_size < 1) {
        ret = -2;
        goto done;
    }
    *result = trim(buffer[0], NULL);
    if (!(*result)) {
        warn("Failed to parse file: \"%s\"", path);
        ret = -3;
        goto done;
    }

    ret = 0;

done:
    free_2d_buffer(&buffer, &buffer_size);

    if (ret != 0) {
        *result = NULL;
    }

    return ret;
}

/*
 * Initialize SysfsCpuCache attributes.
 * @param cache
 */
void init_sysfs_cpu_cache_struct(SysfsCpuCache *cache)
{
    cache->id = NULL;
    cache->size = 0;
    cache->name = NULL;
    cache->level = 0;
    cache->type = NULL;
    cache->ways_of_assoc = 0;
    cache->line_size = 0;
}

/*
 * Check attributes of cache structure and fill in defaults if needed.
 * @param cache
 * @return 0 if success, negative value otherwise
 */
short check_sysfs_cpu_cache_attributes(SysfsCpuCache *cache)
{
    short ret = -1;

    if (!cache->id) {
        if (!(cache->id = strdup(""))) {
            ret = -2;
            goto done;
        }
    }
    if (!cache->name) {
        if (!(cache->name = strdup(""))) {
            ret = -3;
            goto done;
        }
    }
    if (!cache->type) {
        if (!(cache->type = strdup("Unknown"))) {
            ret = -4;
            goto done;
        }
    }

    ret = 0;

done:
    if (ret != 0) {
        warn("Failed to allocate memory.");
    }

    return ret;
}

short sysfs_get_cpu_caches(SysfsCpuCache **caches, unsigned *caches_nb)
{
    short ret = -1;
    unsigned i, level;
    char *buf = NULL, *format_str, path[PATH_MAX];
    DIR *dir;

    *caches_nb = 0;

    /* count caches */
    char *cache_dir = SYSFS_CPU_PATH "/cpu0/cache";
    dir = opendir(cache_dir);
    if (!dir) {
        warn("Failed to read directory: \"%s\"; Error: %s",
                cache_dir, strerror(errno));
        ret = -2;
        goto done;
    }
    while (readdir(dir)) {
        (*caches_nb)++;
    }
    closedir(dir);

    /* do not count . and .. */
    *caches_nb -= 2;

    /* if no cache was found */
    if (*caches_nb < 1) {
        warn("No processor cache was found in sysfs.");
        ret = -3;
        goto done;
    }

    /* allocate memory for caches */
    *caches = (SysfsCpuCache *)calloc(*caches_nb, sizeof(SysfsCpuCache));
    if (!(*caches)) {
        warn("Failed to allocate memory.");
        ret = -4;
        goto done;
    }

    for (i = 0; i < *caches_nb; i++) {
        init_sysfs_cpu_cache_struct(&(*caches)[i]);

        /* cache ID and name */
        /* cache level */
        snprintf(path, PATH_MAX, SYSFS_CPU_PATH "/cpu0/cache/index%u/level", i);
        if (path_get_unsigned(path, &level) != 0) {
            ret = -5;
            goto done;
        }
        (*caches)[i].level = level;
        /* cache type */
        snprintf(path, PATH_MAX, SYSFS_CPU_PATH "/cpu0/cache/index%u/type", i);
        if (path_get_string(path, &buf) != 0) {
            ret = -6;
            goto done;
        }
        if (strncmp(buf, "Data", 4) == 0) {
            format_str = "L%ud-%u";
        } else if (strncmp(buf, "Instruction", 11) == 0) {
            format_str = "L%ui-%u";
        } else {
            format_str = "L%u-%u";
        }
        if (asprintf(&(*caches)[i].id, format_str, level, i) < 0) {
            (*caches)[i].id = NULL;
            warn("Failed to allocate memory.");
            ret = -7;
            goto done;
        }
        if (asprintf(&(*caches)[i].name, "Level %u %s cache",
                level, buf) < 0) {
            (*caches)[i].name = NULL;
            warn("Failed to allocate memory.");
            ret = -8;
            goto done;
        }
        (*caches)[i].type = buf;
        buf = NULL;

        /* cache size */
        snprintf(path, PATH_MAX, SYSFS_CPU_PATH "/cpu0/cache/index%u/size", i);
        if (path_get_unsigned(path, &(*caches)[i].size) != 0) {
            (*caches)[i].size = 0;
        }
        (*caches)[i].size *= 1024;      /* It's in kB, we want B */

        /* ways of associativity */
        snprintf(path, PATH_MAX,
                SYSFS_CPU_PATH "/cpu0/cache/index%u/ways_of_associativity", i);
        if (path_get_unsigned(path, &(*caches)[i].ways_of_assoc) != 0) {
            (*caches)[i].ways_of_assoc = 0;
        }

        /* line size */
        snprintf(path, PATH_MAX,
                SYSFS_CPU_PATH "/cpu0/cache/index%u/coherency_line_size", i);
        if (path_get_unsigned(path, &(*caches)[i].line_size) != 0) {
            (*caches)[i].line_size = 0;
        }

        /* fill in default attributes if needed */
        if (check_sysfs_cpu_cache_attributes(&(*caches)[i]) != 0) {
            ret = -9;
            goto done;
        }
    }

    ret = 0;

done:
    free(buf);
    buf = NULL;

    if (ret != 0) {
        sysfs_free_cpu_caches(caches, caches_nb);
    }

    return ret;
}

void sysfs_free_cpu_caches(SysfsCpuCache **caches, unsigned *caches_nb)
{
    unsigned i;

    if (*caches_nb > 0) {
        for (i = 0; i < *caches_nb; i++) {
            free((*caches)[i].id);
            (*caches)[i].id = NULL;
            free((*caches)[i].name);
            (*caches)[i].name = NULL;
            free((*caches)[i].type);
            (*caches)[i].type = NULL;
        }
        free (*caches);
    }

    *caches_nb = 0;
    *caches = NULL;
}