// SPDX-License-Identifier: GPL-2.0
#include "cap_helpers.h"

/* Avoid including <sys/capability.h> from the libcap-devel package,
 * so directly declare them here and use them from glibc.
 */
int capget(cap_user_header_t header, cap_user_data_t data);
int capset(cap_user_header_t header, const cap_user_data_t data);

int cap_enable_effective(__u64 caps, __u64 *old_caps)
{
        struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
        struct __user_cap_header_struct hdr = {
                .version = _LINUX_CAPABILITY_VERSION_3,
        };
        __u32 cap0 = caps;
        __u32 cap1 = caps >> 32;
        int err;

        err = capget(&hdr, data);
        if (err)
                return -errno;

        if (old_caps)
                *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;

        if ((data[0].effective & cap0) == cap0 &&
            (data[1].effective & cap1) == cap1)
                return 0;

        data[0].effective |= cap0;
        data[1].effective |= cap1;
        err = capset(&hdr, data);
        if (err)
                return -errno;

        return 0;
}

int cap_disable_effective(__u64 caps, __u64 *old_caps)
{
        struct __user_cap_data_struct data[_LINUX_CAPABILITY_U32S_3];
        struct __user_cap_header_struct hdr = {
                .version = _LINUX_CAPABILITY_VERSION_3,
        };
        __u32 cap0 = caps;
        __u32 cap1 = caps >> 32;
        int err;

        err = capget(&hdr, data);
        if (err)
                return -errno;

        if (old_caps)
                *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective;

        if (!(data[0].effective & cap0) && !(data[1].effective & cap1))
                return 0;

        data[0].effective &= ~cap0;
        data[1].effective &= ~cap1;
        err = capset(&hdr, data);
        if (err)
                return -errno;

        return 0;
}