batman-adv: Consolidate logging related functions

There are several places in batman-adv which provide logging related
functions. These should be grouped together in the log.* files to make them
easier to find.

Reported-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

1 files changed, 231 insertions, 0 deletions

diff --git a/net/batman-adv/log.c b/net/batman-adv/log.c
new file mode 100644
index 000000000000..56dc532f7a2c
--- /dev/null
+++ b/net/batman-adv/log.c
@@ -0,0 +1,231 @@
+/* Copyright (C) 2010-2016  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/export.h>
+#include <linux/fcntl.h>
+#include <linux/fs.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/stat.h>
+#include <linux/stddef.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+#include <stdarg.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;
+}
+
+int batadv_debug_log(struct batadv_priv *bat_priv, const char *fmt, ...)
+{
+	va_list args;
+	char tmp_log_buf[256];
+
+	va_start(args, fmt);
+	vscnprintf(tmp_log_buf, sizeof(tmp_log_buf), fmt, args);
+	batadv_fdebug_log(bat_priv->debug_log, "[%10u] %s",
+			  jiffies_to_msecs(jiffies), tmp_log_buf);
+	va_end(args);
+
+	return 0;
+}
+
+static int batadv_log_open(struct inode *inode, struct file *file)
+{
+	if (!try_module_get(THIS_MODULE))
+		return -EBUSY;
+
+	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 unsigned int 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 POLLIN | POLLRDNORM;
+
+	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,
+};
+
+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", S_IFREG | S_IRUSR,
+				bat_priv->debug_dir, bat_priv,
+				&batadv_log_fops);
+	if (!d)
+		goto err;
+
+	return 0;
+
+err:
+	return -ENOMEM;
+}
+
+void batadv_debug_log_cleanup(struct batadv_priv *bat_priv)
+{
+	kfree(bat_priv->debug_log);
+	bat_priv->debug_log = NULL;
+}