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