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ioctl: move doc to README

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Ciro Santilli
2018-07-01 17:44:38 +01:00
parent 084e3faf5a
commit d840b0cb65
7 changed files with 107 additions and 51 deletions
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21
kernel_module/ioctl.c
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@@ -1,23 +1,4 @@
/*
Input: an integer (with some annoying restrictions) and a pointer
Output:
- positive integer return value, which for sanity should only be used with negative values for success
- the input pointer data may be overwritten to contain output
Feels like an archaic API... so many weird restrictions and types for something that could be so simple!
Documentation/ioctl/ioctl-number.txt has some info:
_IO an ioctl with no parameters
_IOW an ioctl with write parameters (copy_from_user)
_IOR an ioctl with read parameters (copy_to_user)
_IOWR an ioctl with both write and read parameters.
- https://stackoverflow.com/questions/2264384/how-do-i-use-ioctl-to-manipulate-my-kernel-module/44613896#44613896
- https://askubuntu.com/questions/54239/problem-with-ioctl-in-a-simple-kernel-module/926675#926675
*/
/* https://github.com/cirosantilli/linux-kernel-module-cheat#ioctl */
#include <linux/debugfs.h>
#include <linux/module.h>