LXR linux/arch/um/kernel/exitcode.c

   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 */
  19int uml_exitcode = 0;
  20
  21static 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
  34static int exitcode_proc_open(struct inode *inode, struct file *file)
  35{
  36        return single_open(file, exitcode_proc_show, NULL);
  37}
  38
  39static 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
  58static 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
  66static 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