/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
/*
 * Implementation of the user-space ashmem API for devices, which have our
 * ashmem-enabled kernel. See ashmem-sim.c for the "fake" tmp-based version,
 * used by the simulator.
 */

#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "ashmem.h"
#include <linux/ashmem.h>

#define ASHMEM_DEVICE "/dev/ashmem"

/*
 * ashmem_create_region - creates a new ashmem region and returns the file
 * descriptor, or <0 on error
 *
 * `name' is an optional label to give the region (visible in /proc/pid/maps)
 * `size' is the size of the region, in page-aligned bytes
 */
int ashmem_create_region(const char* name, size_t size)
{
    int fd, ret;

    fd = open(ASHMEM_DEVICE, O_RDWR);
    if (fd < 0)
        return fd;

    if (name) {
        char buf[ASHMEM_NAME_LEN];

        strlcpy(buf, name, sizeof(buf));
        ret = ioctl(fd, ASHMEM_SET_NAME, buf);
        if (ret < 0)
            goto error;
    }

    ret = ioctl(fd, ASHMEM_SET_SIZE, size);
    if (ret < 0)
        goto error;

    return fd;

error:
    close(fd);
    return ret;
}

int ashmem_set_prot_region(int fd, int prot)
{
    return ioctl(fd, ASHMEM_SET_PROT_MASK, prot);
}

int ashmem_pin_region(int fd, size_t offset, size_t len)
{
    struct ashmem_pin pin = { offset, len };
    return ioctl(fd, ASHMEM_PIN, &pin);
}

int ashmem_unpin_region(int fd, size_t offset, size_t len)
{
    struct ashmem_pin pin = { offset, len };
    return ioctl(fd, ASHMEM_UNPIN, &pin);
}

int ashmem_get_size_region(int fd)
{
    return ioctl(fd, ASHMEM_GET_SIZE, NULL);
}

int ashmem_purge_all(void)
{
    const int fd = open(ASHMEM_DEVICE, O_RDWR);
    if (fd < 0)
        return fd;
    const int ret = ioctl(fd, ASHMEM_PURGE_ALL_CACHES, 0);
    close(fd);
    return ret;
}
