Merge branch 'fixes' into for-linus
[linux-2.6] / arch / um / kernel / exitcode.c
1 /*
2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include <linux/ctype.h>
7 #include <linux/init.h>
8 #include <linux/kernel.h>
9 #include <linux/proc_fs.h>
10 #include <linux/types.h>
11 #include <asm/uaccess.h>
12
13 /*
14  * If read and write race, the read will still atomically read a valid
15  * value.
16  */
17 int uml_exitcode = 0;
18
19 static int read_proc_exitcode(char *page, char **start, off_t off,
20                               int count, int *eof, void *data)
21 {
22         int len, val;
23
24         /*
25          * Save uml_exitcode in a local so that we don't need to guarantee
26          * that sprintf accesses it atomically.
27          */
28         val = uml_exitcode;
29         len = sprintf(page, "%d\n", val);
30         len -= off;
31         if (len <= off+count)
32                 *eof = 1;
33         *start = page + off;
34         if (len > count)
35                 len = count;
36         if (len < 0)
37                 len = 0;
38         return len;
39 }
40
41 static int write_proc_exitcode(struct file *file, const char __user *buffer,
42                                unsigned long count, void *data)
43 {
44         char *end, buf[sizeof("nnnnn\0")];
45         int tmp;
46
47         if (copy_from_user(buf, buffer, count))
48                 return -EFAULT;
49
50         tmp = simple_strtol(buf, &end, 0);
51         if ((*end != '\0') && !isspace(*end))
52                 return -EINVAL;
53
54         uml_exitcode = tmp;
55         return count;
56 }
57
58 static int make_proc_exitcode(void)
59 {
60         struct proc_dir_entry *ent;
61
62         ent = create_proc_entry("exitcode", 0600, NULL);
63         if (ent == NULL) {
64                 printk(KERN_WARNING "make_proc_exitcode : Failed to register "
65                        "/proc/exitcode\n");
66                 return 0;
67         }
68
69         ent->read_proc = read_proc_exitcode;
70         ent->write_proc = write_proc_exitcode;
71
72         return 0;
73 }
74
75 __initcall(make_proc_exitcode);