generic_permission — check for access rights on a Posix-like filesystem
int generic_permission
(struct inode * inode, int mask, int (*check_acl)
(struct inode *inode, int mask));
inode to check access rights for
right to check for (MAY_READ, MAY_WRITE, MAY_EXEC)
optional callback to check for Posix ACLs
Used to check for read/write/execute permissions on a file. We use “fsuid” for this, letting us set arbitrary permissions for filesystem access without changing the “normal” uids which are used for other things..