110 lines
2.0 KiB
C
110 lines
2.0 KiB
C
/*
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* Simple demonstration of the seq_file interface.
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*
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* $Id: seq.c,v 1.3 2004/09/26 07:02:43 gregkh Exp $
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/fs.h>
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#include <linux/seq_file.h>
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#include <linux/slab.h>
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MODULE_AUTHOR("Jonathan Corbet");
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MODULE_LICENSE("Dual BSD/GPL");
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/*
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* The sequence iterator functions. The position as seen by the
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* filesystem is just the count that we return.
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*/
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static void *ct_seq_start(struct seq_file *s, loff_t *pos)
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{
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loff_t *spos = kmalloc(sizeof(loff_t), GFP_KERNEL);
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if (!spos)
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return NULL;
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*spos = *pos;
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return spos;
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}
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static void *ct_seq_next(struct seq_file *s, void *v, loff_t *pos)
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{
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loff_t *spos = (loff_t *) v;
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*pos = ++(*spos);
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return spos;
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}
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static void ct_seq_stop(struct seq_file *s, void *v)
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{
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kfree (v);
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}
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/*
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* The show function.
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*/
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static int ct_seq_show(struct seq_file *s, void *v)
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{
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loff_t *spos = (loff_t *) v;
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seq_printf(s, "%Ld\n", *spos);
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return 0;
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}
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/*
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* Tie them all together into a set of seq_operations.
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*/
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static struct seq_operations ct_seq_ops = {
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.start = ct_seq_start,
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.next = ct_seq_next,
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.stop = ct_seq_stop,
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.show = ct_seq_show
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};
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/*
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* Time to set up the file operations for our /proc file. In this case,
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* all we need is an open function which sets up the sequence ops.
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*/
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static int ct_open(struct inode *inode, struct file *file)
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{
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return seq_open(file, &ct_seq_ops);
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};
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/*
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* The file operations structure contains our open function along with
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* set of the canned seq_ ops.
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*/
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static struct file_operations ct_file_ops = {
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.owner = THIS_MODULE,
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.open = ct_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = seq_release
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};
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/*
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* Module setup and teardown.
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*/
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static int ct_init(void)
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{
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struct proc_dir_entry *entry;
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entry = create_proc_entry("sequence", 0, NULL);
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if (entry)
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entry->proc_fops = &ct_file_ops;
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return 0;
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}
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static void ct_exit(void)
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{
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remove_proc_entry("sequence", NULL);
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}
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module_init(ct_init);
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module_exit(ct_exit);
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