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/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;
  20
  21         len = sprintf(page, "%d\n", uml_exitcode);
  22         len -= off;
  23         if(len <= off+count) *eof = 1;
  24         *start = page + off;
  25         if(len > count) len = count;
  26         if(len < 0) len = 0;
  27         return(len);
  28 }
  29
  30 static int write_proc_exitcode(struct file *file, const char __user *buffer,
  31                                unsigned long count, void *data)
  32 {
  33         char *end, buf[sizeof("nnnnn\0")];
  34         int tmp;
  35
  36         if(copy_from_user(buf, buffer, count))
  37                 return(-EFAULT);
  38         tmp = simple_strtol(buf, &end, 0);
  39         if((*end != '\0') && !isspace(*end))
  40                 return(-EINVAL);
  41         uml_exitcode = tmp;
  42         return(count);
  43 }
  44
  45 static int make_proc_exitcode(void)
  46 {
  47         struct proc_dir_entry *ent;
  48
  49         ent = create_proc_entry("exitcode", 0600, &proc_root);
  50         if(ent == NULL){
  51                 printk("make_proc_exitcode : Failed to register "
  52                        "/proc/exitcode\n");
  53                 return(0);
  54         }
  55
  56         ent->read_proc = read_proc_exitcode;
  57         ent->write_proc = write_proc_exitcode;
  58
  59         return(0);
  60 }
  61
  62 __initcall(make_proc_exitcode);
  63
  64 /*
  65  * Overrides for Emacs so that we follow Linus's tabbing style.
  66  * Emacs will notice this stuff at the end of the file and automatically
  67  * adjust the settings for this buffer only.  This must remain at the end
  68  * of the file.
  69  * ---------------------------------------------------------------------------
  70  * Local variables:
  71  * c-file-style: "linux"
  72  * End:
  73  */