Fixed MTP to work with TWRP

drivers/misc/uid_stat.c

@@ -0,0 +1,152 @@
+/* drivers/misc/uid_stat.c
+ *
+ * Copyright (C) 2008 - 2009 Google, Inc.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+#include <asm/atomic.h>
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stat.h>
+#include <linux/uid_stat.h>
+#include <net/activity_stats.h>
+
+static DEFINE_SPINLOCK(uid_lock);
+static LIST_HEAD(uid_list);
+static struct proc_dir_entry *parent;
+
+struct uid_stat {
+	struct list_head link;
+	uid_t uid;
+	atomic_t tcp_rcv;
+	atomic_t tcp_snd;
+};
+
+static struct uid_stat *find_uid_stat(uid_t uid) {
+	struct uid_stat *entry;
+
+	list_for_each_entry(entry, &uid_list, link) {
+		if (entry->uid == uid) {
+			return entry;
+		}
+	}
+	return NULL;
+}
+
+static int uid_stat_atomic_int_show(struct seq_file *m, void *v)
+{
+	unsigned int bytes;
+	atomic_t *counter = m->private;
+
+	bytes = (unsigned int) (atomic_read(counter) + INT_MIN);
+	return seq_printf(m, "%u\n", bytes);
+}
+
+static int uid_stat_read_atomic_int_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, uid_stat_atomic_int_show, PDE_DATA(inode));
+}
+
+static const struct file_operations uid_stat_read_atomic_int_fops = {
+	.open		= uid_stat_read_atomic_int_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+/* Create a new entry for tracking the specified uid. */
+static struct uid_stat *create_stat(uid_t uid) {
+	struct uid_stat *new_uid;
+	/* Create the uid stat struct and append it to the list. */
+	new_uid = kmalloc(sizeof(struct uid_stat), GFP_ATOMIC);
+	if (!new_uid)
+		return NULL;
+
+	new_uid->uid = uid;
+	/* Counters start at INT_MIN, so we can track 4GB of network traffic. */
+	atomic_set(&new_uid->tcp_rcv, INT_MIN);
+	atomic_set(&new_uid->tcp_snd, INT_MIN);
+
+	list_add_tail(&new_uid->link, &uid_list);
+	return new_uid;
+}
+
+static void create_stat_proc(struct uid_stat *new_uid)
+{
+	char uid_s[32];
+	struct proc_dir_entry *entry;
+	sprintf(uid_s, "%d", new_uid->uid);
+	entry = proc_mkdir(uid_s, parent);
+
+	/* Keep reference to uid_stat so we know what uid to read stats from. */
+	proc_create_data("tcp_snd", S_IRUGO, entry,
+			 &uid_stat_read_atomic_int_fops, &new_uid->tcp_snd);
+
+	proc_create_data("tcp_rcv", S_IRUGO, entry,
+			 &uid_stat_read_atomic_int_fops, &new_uid->tcp_rcv);
+}
+
+static struct uid_stat *find_or_create_uid_stat(uid_t uid)
+{
+	struct uid_stat *entry;
+	unsigned long flags;
+	spin_lock_irqsave(&uid_lock, flags);
+	entry = find_uid_stat(uid);
+	if (entry) {
+		spin_unlock_irqrestore(&uid_lock, flags);
+		return entry;
+	}
+	entry = create_stat(uid);
+	spin_unlock_irqrestore(&uid_lock, flags);
+	if (entry)
+		create_stat_proc(entry);
+	return entry;
+}
+
+int uid_stat_tcp_snd(uid_t uid, int size) {
+	struct uid_stat *entry;
+	activity_stats_update();
+	entry = find_or_create_uid_stat(uid);
+	if (!entry)
+		return -1;
+	atomic_add(size, &entry->tcp_snd);
+	return 0;
+}
+
+int uid_stat_tcp_rcv(uid_t uid, int size) {
+	struct uid_stat *entry;
+	activity_stats_update();
+	entry = find_or_create_uid_stat(uid);
+	if (!entry)
+		return -1;
+	atomic_add(size, &entry->tcp_rcv);
+	return 0;
+}
+
+static int __init uid_stat_init(void)
+{
+	parent = proc_mkdir("uid_stat", NULL);
+	if (!parent) {
+		pr_err("uid_stat: failed to create proc entry\n");
+		return -1;
+	}
+	return 0;
+}
+
+__initcall(uid_stat_init);