[Verse 1] Inside the kernel's sacred space Where hardware meets the code we trace A character driver takes its place One byte at a time through interface Device nodes sleeping in dev slash Waiting for the system's flash Major numbers hold the cache Minor numbers make the dash [Chorus] File ops structure holds the key Open close read write spree Copy to user safely Copy from user carefully Ioctl commands flow free Character streams endlessly [Verse 2] Register chrdev claims the slot Allocate major what you've got Cdev init sets the plot Add to kernel tie the knot Mknod creates the special file Permission bits set the style User space walks that mile Syscalls bridge the compile [Chorus] File ops structure holds the key Open close read write spree Copy to user safely Copy from user carefully Ioctl commands flow free Character streams endlessly [Bridge] Buffer validation every turn Access okay makes kernels learn Get user put user concern Memory faults make systems burn Wait queues block the calling thread Wake up when the data's read Semaphores protect instead Race conditions leave you dead [Verse 3] Module init loads the driver Module exit makes it lighter Probe and remove grow brighter Platform device grows tighter Sysfs entries expose state Debugfs helps investigate Error codes communicate Return values seal the fate [Chorus] File ops structure holds the key Open close read write spree Copy to user safely Copy from user carefully Ioctl commands flow free Character streams endlessly [Outro] From hardware up to user land Character drivers take command One precious byte within your hand The kernel bridge you understand
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