1 /* 2 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com) 3 * Licensed under the GPL 4 */ 5 6 #include "linux/init.h" 7 #include "linux/ctype.h" 8 #include "linux/proc_fs.h" 9 #include "asm/uaccess.h" 10 11 /* If read and write race, the read will still atomically read a valid 12 * value. 13 */ 14 int uml_exitcode = 0; 15 16 static int read_proc_exitcode(char *page, char **start, off_t off, 17 int count, int *eof, void *data) 18 { 19 int len, val; 20 21 /* Save uml_exitcode in a local so that we don't need to guarantee 22 * that sprintf accesses it atomically. 23 */ 24 val = uml_exitcode; 25 len = sprintf(page, "%d\n", val); 26 len -= off; 27 if(len <= off+count) *eof = 1; 28 *start = page + off; 29 if(len > count) len = count; 30 if(len < 0) len = 0; 31 return(len); 32 } 33 34 static int write_proc_exitcode(struct file *file, const char __user *buffer, 35 unsigned long count, void *data) 36 { 37 char *end, buf[sizeof("nnnnn\0")]; 38 int tmp; 39 40 if(copy_from_user(buf, buffer, count)) 41 return(-EFAULT); 42 tmp = simple_strtol(buf, &end, 0); 43 if((*end != '\0') && !isspace(*end)) 44 return(-EINVAL); 45 uml_exitcode = tmp; 46 return(count); 47 } 48 49 static int make_proc_exitcode(void) 50 { 51 struct proc_dir_entry *ent; 52 53 ent = create_proc_entry("exitcode", 0600, &proc_root); 54 if(ent == NULL){ 55 printk(KERN_WARNING "make_proc_exitcode : Failed to register " 56 "/proc/exitcode\n"); 57 return(0); 58 } 59 60 ent->read_proc = read_proc_exitcode; 61 ent->write_proc = write_proc_exitcode; 62 63 return(0); 64 } 65 66 __initcall(make_proc_exitcode); 67 68 /* 69 * Overrides for Emacs so that we follow Linus's tabbing style. 70 * Emacs will notice this stuff at the end of the file and automatically 71 * adjust the settings for this buffer only. This must remain at the end 72 * of the file. 73 * --------------------------------------------------------------------------- 74 * Local variables: 75 * c-file-style: "linux" 76 * End: 77 */ 78