6613c5e860
Convert code away from ->read_proc/->write_proc interfaces. Switch to
proc_create()/proc_create_data() which make addition of proc entries
reliable wrt NULL ->proc_fops, NULL ->data and so on.
Problem with ->read_proc et al is described here commit
786d7e1612 "Fix rmmod/read/write races in
/proc entries"
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
78 lines
1.6 KiB
C
78 lines
1.6 KiB
C
/*
|
|
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
|
|
* Licensed under the GPL
|
|
*/
|
|
|
|
#include <linux/ctype.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/types.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
/*
|
|
* If read and write race, the read will still atomically read a valid
|
|
* value.
|
|
*/
|
|
int uml_exitcode = 0;
|
|
|
|
static int exitcode_proc_show(struct seq_file *m, void *v)
|
|
{
|
|
int val;
|
|
|
|
/*
|
|
* Save uml_exitcode in a local so that we don't need to guarantee
|
|
* that sprintf accesses it atomically.
|
|
*/
|
|
val = uml_exitcode;
|
|
seq_printf(m, "%d\n", val);
|
|
return 0;
|
|
}
|
|
|
|
static int exitcode_proc_open(struct inode *inode, struct file *file)
|
|
{
|
|
return single_open(file, exitcode_proc_show, NULL);
|
|
}
|
|
|
|
static ssize_t exitcode_proc_write(struct file *file,
|
|
const char __user *buffer, size_t count, loff_t *pos)
|
|
{
|
|
char *end, buf[sizeof("nnnnn\0")];
|
|
int tmp;
|
|
|
|
if (copy_from_user(buf, buffer, count))
|
|
return -EFAULT;
|
|
|
|
tmp = simple_strtol(buf, &end, 0);
|
|
if ((*end != '\0') && !isspace(*end))
|
|
return -EINVAL;
|
|
|
|
uml_exitcode = tmp;
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations exitcode_proc_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = exitcode_proc_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
.write = exitcode_proc_write,
|
|
};
|
|
|
|
static int make_proc_exitcode(void)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
|
|
ent = proc_create("exitcode", 0600, NULL, &exitcode_proc_fops);
|
|
if (ent == NULL) {
|
|
printk(KERN_WARNING "make_proc_exitcode : Failed to register "
|
|
"/proc/exitcode\n");
|
|
return 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
__initcall(make_proc_exitcode);
|