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https://github.com/cirosantilli/linux-kernel-module-cheat.git
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48 lines
1022 B
C
48 lines
1022 B
C
/*
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Adapted from: https://github.com/chadversary/debugfs-tutorial/blob/47b3cf7ca47208c61ccb51b27aac6f9f932bfe0b/example1/debugfs_example1.c
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Usage:
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/debugfs.sh
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Requires `CONFIG_DEBUG_FS=y`.
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Only the more basic fops can be implemented in debugfs, e.g. mmap is never called:
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- https://patchwork.kernel.org/patch/9252557/
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- https://github.com/torvalds/linux/blob/v4.9/fs/debugfs/file.c#L212
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*/
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#include <linux/debugfs.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <uapi/linux/stat.h> /* S_IRUSR */
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static struct dentry *dir;
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static u32 value = 42;
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static int myinit(void)
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{
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struct dentry *file;
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dir = debugfs_create_dir("lkmc_debugfs", 0);
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if (!dir) {
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printk(KERN_ALERT "debugfs_create_dir failed");
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return -1;
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}
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file = debugfs_create_u32("myfile", S_IRUSR, dir, &value);
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if (!file) {
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printk(KERN_ALERT "debugfs_create_u32 failed");
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return -1;
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}
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return 0;
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}
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static void myexit(void)
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{
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debugfs_remove_recursive(dir);
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}
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module_init(myinit)
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module_exit(myexit)
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MODULE_LICENSE("GPL");
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