![Taehee Yoo](/assets/img/avatar_default.png)
If THIS_MODULE is not set, the module would be removed while debugfs is
being used.
It eventually makes kernel panic.
Fixes: c6c8fea297
("net: Add batman-adv meshing protocol")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
246 lines
5.4 KiB
C
246 lines
5.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 2010-2020 B.A.T.M.A.N. contributors:
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*
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* Marek Lindner
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*/
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#include "log.h"
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#include "main.h"
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#include <linux/compiler.h>
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#include <linux/debugfs.h>
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#include <linux/errno.h>
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#include <linux/eventpoll.h>
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#include <linux/export.h>
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#include <linux/fcntl.h>
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#include <linux/fs.h>
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#include <linux/gfp.h>
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#include <linux/jiffies.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/poll.h>
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#include <linux/sched.h> /* for linux/wait.h */
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/stddef.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/wait.h>
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#include <stdarg.h>
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#include "debugfs.h"
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#include "trace.h"
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#ifdef CONFIG_BATMAN_ADV_DEBUGFS
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#define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)
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static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN;
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static char *batadv_log_char_addr(struct batadv_priv_debug_log *debug_log,
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size_t idx)
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{
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return &debug_log->log_buff[idx & BATADV_LOG_BUFF_MASK];
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}
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static void batadv_emit_log_char(struct batadv_priv_debug_log *debug_log,
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char c)
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{
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char *char_addr;
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char_addr = batadv_log_char_addr(debug_log, debug_log->log_end);
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*char_addr = c;
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debug_log->log_end++;
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if (debug_log->log_end - debug_log->log_start > batadv_log_buff_len)
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debug_log->log_start = debug_log->log_end - batadv_log_buff_len;
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}
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__printf(2, 3)
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static int batadv_fdebug_log(struct batadv_priv_debug_log *debug_log,
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const char *fmt, ...)
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{
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va_list args;
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static char debug_log_buf[256];
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char *p;
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if (!debug_log)
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return 0;
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spin_lock_bh(&debug_log->lock);
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va_start(args, fmt);
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vscnprintf(debug_log_buf, sizeof(debug_log_buf), fmt, args);
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va_end(args);
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for (p = debug_log_buf; *p != 0; p++)
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batadv_emit_log_char(debug_log, *p);
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spin_unlock_bh(&debug_log->lock);
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wake_up(&debug_log->queue_wait);
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return 0;
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}
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static int batadv_log_open(struct inode *inode, struct file *file)
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{
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if (!try_module_get(THIS_MODULE))
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return -EBUSY;
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batadv_debugfs_deprecated(file,
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"Use tracepoint batadv:batadv_dbg instead\n");
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stream_open(inode, file);
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file->private_data = inode->i_private;
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return 0;
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}
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static int batadv_log_release(struct inode *inode, struct file *file)
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{
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module_put(THIS_MODULE);
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return 0;
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}
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static bool batadv_log_empty(struct batadv_priv_debug_log *debug_log)
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{
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return !(debug_log->log_start - debug_log->log_end);
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}
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static ssize_t batadv_log_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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struct batadv_priv *bat_priv = file->private_data;
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struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;
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int error, i = 0;
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char *char_addr;
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char c;
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if ((file->f_flags & O_NONBLOCK) && batadv_log_empty(debug_log))
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return -EAGAIN;
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if (!buf)
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return -EINVAL;
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if (count == 0)
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return 0;
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if (!access_ok(buf, count))
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return -EFAULT;
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error = wait_event_interruptible(debug_log->queue_wait,
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(!batadv_log_empty(debug_log)));
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if (error)
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return error;
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spin_lock_bh(&debug_log->lock);
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while ((!error) && (i < count) &&
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(debug_log->log_start != debug_log->log_end)) {
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char_addr = batadv_log_char_addr(debug_log,
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debug_log->log_start);
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c = *char_addr;
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debug_log->log_start++;
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spin_unlock_bh(&debug_log->lock);
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error = __put_user(c, buf);
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spin_lock_bh(&debug_log->lock);
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buf++;
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i++;
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}
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spin_unlock_bh(&debug_log->lock);
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if (!error)
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return i;
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return error;
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}
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static __poll_t batadv_log_poll(struct file *file, poll_table *wait)
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{
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struct batadv_priv *bat_priv = file->private_data;
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struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;
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poll_wait(file, &debug_log->queue_wait, wait);
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if (!batadv_log_empty(debug_log))
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return EPOLLIN | EPOLLRDNORM;
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return 0;
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}
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static const struct file_operations batadv_log_fops = {
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.open = batadv_log_open,
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.release = batadv_log_release,
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.read = batadv_log_read,
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.poll = batadv_log_poll,
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.llseek = no_llseek,
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.owner = THIS_MODULE,
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};
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/**
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* batadv_debug_log_setup() - Initialize debug log
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* @bat_priv: the bat priv with all the soft interface information
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*
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* Return: 0 on success or negative error number in case of failure
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*/
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int batadv_debug_log_setup(struct batadv_priv *bat_priv)
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{
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bat_priv->debug_log = kzalloc(sizeof(*bat_priv->debug_log), GFP_ATOMIC);
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if (!bat_priv->debug_log)
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return -ENOMEM;
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spin_lock_init(&bat_priv->debug_log->lock);
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init_waitqueue_head(&bat_priv->debug_log->queue_wait);
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debugfs_create_file("log", 0400, bat_priv->debug_dir, bat_priv,
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&batadv_log_fops);
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return 0;
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}
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/**
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* batadv_debug_log_cleanup() - Destroy debug log
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* @bat_priv: the bat priv with all the soft interface information
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*/
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void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
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{
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kfree(bat_priv->debug_log);
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bat_priv->debug_log = NULL;
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}
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#endif /* CONFIG_BATMAN_ADV_DEBUGFS */
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/**
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* batadv_debug_log() - Add debug log entry
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* @bat_priv: the bat priv with all the soft interface information
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* @fmt: format string
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*
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* Return: 0 on success or negative error number in case of failure
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*/
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int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
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{
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struct va_format vaf;
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va_list args;
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va_start(args, fmt);
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vaf.fmt = fmt;
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vaf.va = &args;
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#ifdef CONFIG_BATMAN_ADV_DEBUGFS
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batadv_fdebug_log(bat_priv->debug_log, "[%10u] %pV",
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jiffies_to_msecs(jiffies), &vaf);
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#endif
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trace_batadv_dbg(bat_priv, &vaf);
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va_end(args);
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return 0;
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}
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