Skip to content

Embedded Linux Learning

file_operations

`struct file_operations`¶

Purpose¶

struct file_operations defines how a character device responds to user-space file operations.

Common Callbacks¶

static const struct file_operations mydev_fops = {
    .owner = THIS_MODULE,
    .open = mydev_open,
    .read = mydev_read,
    .write = mydev_write,
    .poll = mydev_poll,
    .unlocked_ioctl = mydev_ioctl,
    .fasync = mydev_fasync,
    .release = mydev_release,
};

Common Fields¶

Field	Purpose
`.open`	Initialize per-open state
`.read`	Copy data or events to user space
`.write`	Accept user-space commands or data
`.poll`	Report readiness to `poll` / `epoll`
`.unlocked_ioctl`	Handle control commands
`.fasync`	Register async signal notification
`.release`	Cleanup per-open state