linux/net/batman-adv/log.c
Sven Eckelmann d331a73994 batman-adv: Provide debug messages as trace events
A private debug logging infrastructure is currently provided via
$debug_fs/batman_adv/*/log when CONFIG_BATMAN_ADV_DEBUG is enabled. This is
not well integrated in the rest of the tracing infrastructure of the
kernel.

Other components (like mac80211 or ath10k) allow to gather the debug
messages using generic trace events which are better integrated. This makes
it possible to interact with them using the existing userspace tools.

The tracepoint batadv:batadv_dbg will now be available when
CONFIG_BATMAN_ADV_DEBUG and CONFIG_BATMAN_ADV_TRACING is activated. The log
level mask is still used for filtering as usual.

A full system trace for offline parsing can be created (and read) using:

  $ batctl ll all
  $ trace-cmd record -e batadv:batadv_dbg
  $ trace-cmd report

The same can also be done without recording to a file

  $ batctl ll all
  $ trace-cmd stream -e batadv:batadv_dbg

The trace infrastructure is especially helpful when tracing processes:

  $ batctl ll all
  $ ./tools/perf/perf trace --event "batadv:*" batctl p 10.204.32.1
     0.000 batadv:batadv_dbg:batman_adv bat0 Parsing outgoing ARP REQUEST
     0.045 batadv:batadv_dbg:batman_adv bat0 ARP MSG = [src: a2:64:14:53:f8:22-10.204.32.185 dst: 00:00:00:00:00:00-10.204.32.1]
     0.067 batadv:batadv_dbg:batman_adv bat0 Entry updated: 10.204.32.185 a2:64:14:53:f8:22 (vid: -1)
     0.099 batadv:batadv_dbg:batman_adv bat0 batadv_dat_select_candidates(): IP=10.204.32.1 hash(IP)=48902
     0.757 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 0: selected fe:2c:91:68:29:2b addr=48977 dist=65460
     1.178 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 1: selected fe:81:ab:c5:e3:03 addr=49181 dist=65256
     1.809 batadv:batadv_dbg:batman_adv bat0 dat_select_candidates() 2: selected 66:25:a7:48:37:fb addr=49328 dist=65109
     1.828 batadv:batadv_dbg:batman_adv bat0 DHT_SEND for 10.204.32.1

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
2018-09-15 09:51:08 +02:00

262 lines
5.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2010-2018 B.A.T.M.A.N. contributors:
*
* Marek Lindner
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include "log.h"
#include "main.h"
#include <linux/compiler.h>
#include <linux/debugfs.h>
#include <linux/errno.h>
#include <linux/eventpoll.h>
#include <linux/export.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/poll.h>
#include <linux/sched.h> /* for linux/wait.h */
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/stddef.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <stdarg.h>
#include "debugfs.h"
#include "trace.h"
#define BATADV_LOG_BUFF_MASK (batadv_log_buff_len - 1)
static const int batadv_log_buff_len = BATADV_LOG_BUF_LEN;
static char *batadv_log_char_addr(struct batadv_priv_debug_log *debug_log,
size_t idx)
{
return &debug_log->log_buff[idx & BATADV_LOG_BUFF_MASK];
}
static void batadv_emit_log_char(struct batadv_priv_debug_log *debug_log,
char c)
{
char *char_addr;
char_addr = batadv_log_char_addr(debug_log, debug_log->log_end);
*char_addr = c;
debug_log->log_end++;
if (debug_log->log_end - debug_log->log_start > batadv_log_buff_len)
debug_log->log_start = debug_log->log_end - batadv_log_buff_len;
}
__printf(2, 3)
static int batadv_fdebug_log(struct batadv_priv_debug_log *debug_log,
const char *fmt, ...)
{
va_list args;
static char debug_log_buf[256];
char *p;
if (!debug_log)
return 0;
spin_lock_bh(&debug_log->lock);
va_start(args, fmt);
vscnprintf(debug_log_buf, sizeof(debug_log_buf), fmt, args);
va_end(args);
for (p = debug_log_buf; *p != 0; p++)
batadv_emit_log_char(debug_log, *p);
spin_unlock_bh(&debug_log->lock);
wake_up(&debug_log->queue_wait);
return 0;
}
/**
* batadv_debug_log() - Add debug log entry
* @bat_priv: the bat priv with all the soft interface information
* @fmt: format string
*
* Return: 0 on success or negative error number in case of failure
*/
int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
batadv_fdebug_log(bat_priv->debug_log, "[%10u] %pV",
jiffies_to_msecs(jiffies), &vaf);
trace_batadv_dbg(bat_priv, &vaf);
va_end(args);
return 0;
}
static int batadv_log_open(struct inode *inode, struct file *file)
{
if (!try_module_get(THIS_MODULE))
return -EBUSY;
batadv_debugfs_deprecated(file,
"Use tracepoint batadv:batadv_dbg instead\n");
nonseekable_open(inode, file);
file->private_data = inode->i_private;
return 0;
}
static int batadv_log_release(struct inode *inode, struct file *file)
{
module_put(THIS_MODULE);
return 0;
}
static bool batadv_log_empty(struct batadv_priv_debug_log *debug_log)
{
return !(debug_log->log_start - debug_log->log_end);
}
static ssize_t batadv_log_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct batadv_priv *bat_priv = file->private_data;
struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;
int error, i = 0;
char *char_addr;
char c;
if ((file->f_flags & O_NONBLOCK) && batadv_log_empty(debug_log))
return -EAGAIN;
if (!buf)
return -EINVAL;
if (count == 0)
return 0;
if (!access_ok(VERIFY_WRITE, buf, count))
return -EFAULT;
error = wait_event_interruptible(debug_log->queue_wait,
(!batadv_log_empty(debug_log)));
if (error)
return error;
spin_lock_bh(&debug_log->lock);
while ((!error) && (i < count) &&
(debug_log->log_start != debug_log->log_end)) {
char_addr = batadv_log_char_addr(debug_log,
debug_log->log_start);
c = *char_addr;
debug_log->log_start++;
spin_unlock_bh(&debug_log->lock);
error = __put_user(c, buf);
spin_lock_bh(&debug_log->lock);
buf++;
i++;
}
spin_unlock_bh(&debug_log->lock);
if (!error)
return i;
return error;
}
static __poll_t batadv_log_poll(struct file *file, poll_table *wait)
{
struct batadv_priv *bat_priv = file->private_data;
struct batadv_priv_debug_log *debug_log = bat_priv->debug_log;
poll_wait(file, &debug_log->queue_wait, wait);
if (!batadv_log_empty(debug_log))
return EPOLLIN | EPOLLRDNORM;
return 0;
}
static const struct file_operations batadv_log_fops = {
.open = batadv_log_open,
.release = batadv_log_release,
.read = batadv_log_read,
.poll = batadv_log_poll,
.llseek = no_llseek,
};
/**
* batadv_debug_log_setup() - Initialize debug log
* @bat_priv: the bat priv with all the soft interface information
*
* Return: 0 on success or negative error number in case of failure
*/
int batadv_debug_log_setup(struct batadv_priv *bat_priv)
{
struct dentry *d;
if (!bat_priv->debug_dir)
goto err;
bat_priv->debug_log = kzalloc(sizeof(*bat_priv->debug_log), GFP_ATOMIC);
if (!bat_priv->debug_log)
goto err;
spin_lock_init(&bat_priv->debug_log->lock);
init_waitqueue_head(&bat_priv->debug_log->queue_wait);
d = debugfs_create_file("log", 0400, bat_priv->debug_dir, bat_priv,
&batadv_log_fops);
if (!d)
goto err;
return 0;
err:
return -ENOMEM;
}
/**
* batadv_debug_log_cleanup() - Destroy debug log
* @bat_priv: the bat priv with all the soft interface information
*/
void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
{
kfree(bat_priv->debug_log);
bat_priv->debug_log = NULL;
}