data.c

/* SPDX-License-Identifier: LGPL-2.1-only */
/*
 * Copyright (c) 2003-2012 Thomas Graf <tgraf@suug.ch>
 */
 
/**
 * @ingroup core_types
 * @defgroup data Abstract Data
 *
 * Abstract data type representing a binary data blob.
 *
 * Related sections in the development guide:
 * - @core_doc{_abstract_data, Abstract Data}
 *
 * @{
 *
 * Header
 * ------
 * ~~~~{.c}
 * #include <netlink/data.h>
 * ~~~~
 */
 
#include <netlink-private/netlink.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <linux/socket.h>
 
/**
 * @name General
 * @{
 */
 
/**
 * Allocate a new abstract data object.
 * @arg buf             Data buffer containing the actual data.
 * @arg size            Size of data buffer.
 *
 * Allocates a new abstract data and copies the specified data
 * buffer into the new handle.
 * 
 * @return Newly allocated data handle or NULL
 */
struct nl_data *nl_data_alloc(const void *buf, size_t size)
{
        struct nl_data *data;
 
        data = calloc(1, sizeof(*data));
        if (!data)
                goto errout;
 
        data->d_data = calloc(1, size);
        if (!data->d_data) {
                free(data);
                goto errout;
        }
 
        data->d_size = size;
 
        if (buf)
                memcpy(data->d_data, buf, size);
 
        return data;
errout:
        return NULL;
}
 
/**
 * Allocate abstract data object based on netlink attribute.
 * @arg nla             Netlink attribute of unspecific type.
 *
 * Allocates a new abstract data and copies the payload of the
 * attribute to the abstract data object.
 * 
 * @see nla_data_alloc
 * @return Newly allocated data handle or NULL
 */
struct nl_data *nl_data_alloc_attr(const struct nlattr *nla)
{
        return nl_data_alloc(nla_data(nla), nla_len(nla));
}
 
/**
 * Clone an abstract data object.
 * @arg src             Abstract data object
 *
 * @return Cloned object or NULL
 */
struct nl_data *nl_data_clone(const struct nl_data *src)
{
        return nl_data_alloc(src->d_data, src->d_size);
}
 
/**
 * Append data to an abstract data object.
 * @arg data            Abstract data object.
 * @arg buf             Data buffer containing the data to be appended.
 * @arg size            Size of data to be apppended.
 *
 * Reallocates an abstract data and copies the specified data
 * buffer into the new handle.
 * 
 * @return 0 on success or a negative error code
 */
int nl_data_append(struct nl_data *data, const void *buf, size_t size)
{
        if (size > 0) {
                char *d_data = realloc(data->d_data, data->d_size + size);
                if (!d_data)
                        return -NLE_NOMEM;
 
                if (buf)
                        memcpy(d_data + data->d_size, buf, size);
                else
                        memset(d_data + data->d_size, 0, size);
 
                data->d_data = d_data;
                data->d_size += size;
        }
 
        return 0;
}
 
/**
 * Free an abstract data object.
 * @arg data            Abstract data object.
 */
void nl_data_free(struct nl_data *data)
{
        if (data)
                free(data->d_data);
 
        free(data);
}
 
/** @} */
 
/**
 * @name Attribute Access
 * @{
 */
 
/**
 * Get data buffer of abstract data object.
 * @arg data            Abstract data object.
 * @return Data buffer or NULL if empty.
 */
void *nl_data_get(const struct nl_data *data)
{
        if (data->d_size > 0)
                return (void*)data->d_data;
        return NULL;
}
 
/**
 * Get size of data buffer of abstract data object.
 * @arg data            Abstract data object.
 * @return Size of data buffer.
 */
size_t nl_data_get_size(const struct nl_data *data)
{
        return data->d_size;
}
 
/** @} */
 
/**
 * @name Misc
 * @{
 */
 
/**
 * Compare two abstract data objects.
 * @arg a               Abstract data object.
 * @arg b               Another abstract data object.
 * @return An integer less than, equal to, or greater than zero if
 *         a is found, respectively, to be less than, to match, or
 *         be greater than b.
 */
int nl_data_cmp(const struct nl_data *a, const struct nl_data *b)
{
        const void *a_ = nl_data_get(a);
        const void *b_ = nl_data_get(b);
 
        if (a_ && b_)
                return memcmp(a_, b_, nl_data_get_size(a));
        else
                return -1;
}
 
/** @} */
/** @} */