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/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 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 34 static int exitcode_proc_open(struct inode *inode, struct file *file) 35 { 36 return single_open(file, exitcode_proc_show, NULL); 37 } 38 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 file_operations exitcode_proc_fops = { 59 .owner = THIS_MODULE, 60 .open = exitcode_proc_open, 61 .read = seq_read, 62 .llseek = seq_lseek, 63 .release = single_release, 64 .write = exitcode_proc_write, 65 }; 66 67 static int make_proc_exitcode(void) 68 { 69 struct proc_dir_entry *ent; 70 71 ent = proc_create("exitcode", 0600, NULL, &exitcode_proc_fops); 72 if (ent == NULL) { 73 printk(KERN_WARNING "make_proc_exitcode : Failed to register " 74 "/proc/exitcode\n"); 75 return 0; 76 } 77 return 0; 78 } 79 80 __initcall(make_proc_exitcode); 81