Editing IOCTL
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In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular file semantics. It takes a parameter specifying a request code; the effect of a call depends completely on the request code. Request codes are often device-specific. For instance, a CD-ROM device driver which can instruct a physical device to eject a disc would provide an ioctl request code to do so. Device-independent request codes are sometimes used to give | In computing, ioctl (an abbreviation of input/output control) is a system call for device-specific input/output operations and other operations which cannot be expressed by regular file semantics. It takes a parameter specifying a request code; the effect of a call depends completely on the request code. Request codes are often device-specific. For instance, a CD-ROM device driver which can instruct a physical device to eject a disc would provide an ioctl request code to do so. Device-independent request codes are sometimes used to give usermdoe access to kernel functions which are only used by core system software or still under development. | ||
See also [https://en.wikipedia.org/wiki/Ioctl wikipedia page about IOCTL]. | See also [https://en.wikipedia.org/wiki/Ioctl wikipedia page about IOCTL]. | ||
= Description = | = Description = | ||
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* Thanks to SocraticBliss for the names. | * Thanks to SocraticBliss for the names. | ||
= | = FInding the IOCTL handler address for a device in kernel = | ||
<pre> | |||
Find a string of the device name in kernel. | |||
There should be only two cross-references from function: make_dev and mutex_init. make_dev is the interesting one. | |||
The structure before the device string is where we want to go. | |||
Follow the structure then go to the very last offset of the structure. | |||
It is the handler function in charge of IOCTLs for that device. | |||
</pre> | </pre> | ||