1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6 #include <linux/ctype.h>
7 #include <linux/init.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/proc_fs.h>
11 #include <linux/seq_file.h>
12 #include <linux/types.h>
13 #include <linux/uaccess.h>
14
15 /*
16 * If read and write race, the read will still atomically read a valid
17 * value.
18 */
19 int uml_exitcode = 0;
20
exitcode_proc_show(struct seq_file * m,void * v)21 static int exitcode_proc_show(struct seq_file *m, void *v)
22 {
23 int val;
24
25 /*
26 * Save uml_exitcode in a local so that we don't need to guarantee
27 * that sprintf accesses it atomically.
28 */
29 val = uml_exitcode;
30 seq_printf(m, "%d\n", val);
31 return 0;
32 }
33
exitcode_proc_open(struct inode * inode,struct file * file)34 static int exitcode_proc_open(struct inode *inode, struct file *file)
35 {
36 return single_open(file, exitcode_proc_show, NULL);
37 }
38
exitcode_proc_write(struct file * file,const char __user * buffer,size_t count,loff_t * pos)39 static ssize_t exitcode_proc_write(struct file *file,
40 const char __user *buffer, size_t count, loff_t *pos)
41 {
42 char *end, buf[sizeof("nnnnn\0")];
43 size_t size;
44 int tmp;
45
46 size = min(count, sizeof(buf));
47 if (copy_from_user(buf, buffer, size))
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 const struct proc_ops exitcode_proc_ops = {
59 .proc_open = exitcode_proc_open,
60 .proc_read = seq_read,
61 .proc_lseek = seq_lseek,
62 .proc_release = single_release,
63 .proc_write = exitcode_proc_write,
64 };
65
make_proc_exitcode(void)66 static int make_proc_exitcode(void)
67 {
68 struct proc_dir_entry *ent;
69
70 ent = proc_create("exitcode", 0600, NULL, &exitcode_proc_ops);
71 if (ent == NULL) {
72 printk(KERN_WARNING "make_proc_exitcode : Failed to register "
73 "/proc/exitcode\n");
74 return 0;
75 }
76 return 0;
77 }
78
79 __initcall(make_proc_exitcode);
80