76 lines
1.5 KiB
C
76 lines
1.5 KiB
C
/*
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* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
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* Licensed under the GPL
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*/
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#include <linux/ctype.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/proc_fs.h>
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#include <linux/types.h>
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#include <asm/uaccess.h>
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/*
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* If read and write race, the read will still atomically read a valid
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* value.
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*/
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int uml_exitcode = 0;
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static int read_proc_exitcode(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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int len, val;
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/*
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* Save uml_exitcode in a local so that we don't need to guarantee
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* that sprintf accesses it atomically.
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*/
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val = uml_exitcode;
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len = sprintf(page, "%d\n", val);
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len -= off;
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if (len <= off+count)
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*eof = 1;
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*start = page + off;
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if (len > count)
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len = count;
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if (len < 0)
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len = 0;
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return len;
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}
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static int write_proc_exitcode(struct file *file, const char __user *buffer,
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unsigned long count, void *data)
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{
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char *end, buf[sizeof("nnnnn\0")];
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int tmp;
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if (copy_from_user(buf, buffer, count))
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return -EFAULT;
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tmp = simple_strtol(buf, &end, 0);
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if ((*end != '\0') && !isspace(*end))
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return -EINVAL;
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uml_exitcode = tmp;
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return count;
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}
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static int make_proc_exitcode(void)
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{
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struct proc_dir_entry *ent;
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ent = create_proc_entry("exitcode", 0600, NULL);
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if (ent == NULL) {
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printk(KERN_WARNING "make_proc_exitcode : Failed to register "
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"/proc/exitcode\n");
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return 0;
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}
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ent->read_proc = read_proc_exitcode;
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ent->write_proc = write_proc_exitcode;
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return 0;
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}
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__initcall(make_proc_exitcode);
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