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, 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  */