/* SPDX-License-Identifier: GPL-2.0 */
#include <linux/fs.h>

#define DEVCG_ACC_MKNOD 1
#define DEVCG_ACC_READ  2
#define DEVCG_ACC_WRITE 4
#define DEVCG_ACC_MASK (DEVCG_ACC_MKNOD | DEVCG_ACC_READ | DEVCG_ACC_WRITE)

#define DEVCG_DEV_BLOCK 1
#define DEVCG_DEV_CHAR  2
#define DEVCG_DEV_ALL   4  /* this represents all devices */


#if defined(CONFIG_CGROUP_DEVICE) || defined(CONFIG_CGROUP_BPF)
int devcgroup_check_permission(short type, u32 major, u32 minor,
                               short access);
static inline int devcgroup_inode_permission(struct inode *inode, int mask)
{
        short type, access = 0;

        if (likely(!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)))
                return 0;

        if (!inode->i_rdev)
                return 0;

        if (S_ISBLK(inode->i_mode))
                type = DEVCG_DEV_BLOCK;
        else /* S_ISCHR by the test above */
                type = DEVCG_DEV_CHAR;

        if (mask & MAY_WRITE)
                access |= DEVCG_ACC_WRITE;
        if (mask & MAY_READ)
                access |= DEVCG_ACC_READ;

        return devcgroup_check_permission(type, imajor(inode), iminor(inode),
                                          access);
}

static inline int devcgroup_inode_mknod(int mode, dev_t dev)
{
        short type;

        if (!S_ISBLK(mode) && !S_ISCHR(mode))
                return 0;

        if (S_ISCHR(mode) && dev == WHITEOUT_DEV)
                return 0;

        if (S_ISBLK(mode))
                type = DEVCG_DEV_BLOCK;
        else
                type = DEVCG_DEV_CHAR;

        return devcgroup_check_permission(type, MAJOR(dev), MINOR(dev),
                                          DEVCG_ACC_MKNOD);
}

#else
static inline int devcgroup_check_permission(short type, u32 major, u32 minor,
                               short access)
{ return 0; }
static inline int devcgroup_inode_permission(struct inode *inode, int mask)
{ return 0; }
static inline int devcgroup_inode_mknod(int mode, dev_t dev)
{ return 0; }
#endif