sysinfo.c

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/*
 * Copyright (c) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <libc.h>
#include <sysinfo.h>
#include <str.h>
#include <errno.h>
#include <malloc.h>
#include <bool.h>

sysinfo_item_tag_t sysinfo_get_tag(const char *path)
{
        return (sysinfo_item_tag_t) __SYSCALL2(SYS_SYSINFO_GET_TAG,
            (sysarg_t) path, (sysarg_t) str_size(path));
}

int sysinfo_get_value(const char *path, sysarg_t *value)
{
        return (int) __SYSCALL3(SYS_SYSINFO_GET_VALUE, (sysarg_t) path,
            (sysarg_t) str_size(path), (sysarg_t) value);
}

static int sysinfo_get_data_size(const char *path, size_t *size)
{
        return (int) __SYSCALL3(SYS_SYSINFO_GET_DATA_SIZE, (sysarg_t) path,
            (sysarg_t) str_size(path), (sysarg_t) size);
}

void *sysinfo_get_data(const char *path, size_t *size)
{
        /*
         * The binary data size might change during time.
         * Unfortunatelly we cannot allocate the buffer
         * and transfer the data as a single atomic operation.
         */
        
        /* Get the binary data size */
        int ret = sysinfo_get_data_size(path, size);
        if ((ret != EOK) || (size == 0)) {
                /*
                 * Not a binary data item
                 * or an empty item.
                 */
                *size = 0;
                return NULL;
        }
        
        void *data = malloc(*size);
        if (data == NULL) {
                *size = 0;
                return NULL;
        }
        
        /* Get the data */
        size_t sz;
        ret = __SYSCALL5(SYS_SYSINFO_GET_DATA, (sysarg_t) path,
            (sysarg_t) str_size(path), (sysarg_t) data, (sysarg_t) *size,
            (sysarg_t) &sz);
        if (ret == EOK) {
                *size = sz;
                return data;
        }
        
        free(data);
        *size = 0;
        return NULL;
}

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