cregit-Linux how code gets into the kernel

Release 4.7 drivers/char/tpm/tpm-dev.c

Directory: drivers/char/tpm
/*
 * Copyright (C) 2004 IBM Corporation
 * Authors:
 * Leendert van Doorn <leendert@watson.ibm.com>
 * Dave Safford <safford@watson.ibm.com>
 * Reiner Sailer <sailer@watson.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * Copyright (C) 2013 Obsidian Research Corp
 * Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
 *
 * Device file system interface to the TPM
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 *
 */
#include <linux/slab.h>
#include <linux/uaccess.h>
#include "tpm.h"


struct file_priv {
	
struct tpm_chip *chip;

	/* Data passed to and from the tpm via the read/write calls */
	
atomic_t data_pending;
	
struct mutex buffer_mutex;

	
struct timer_list user_read_timer;      /* user needs to claim result */
	
struct work_struct work;

	
u8 data_buffer[TPM_BUFSIZE];
};


static void user_reader_timeout(unsigned long ptr) { struct file_priv *priv = (struct file_priv *)ptr; schedule_work(&priv->work); }

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jason gunthorpejason gunthorpe30100.00%2100.00%
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static void timeout_work(struct work_struct *work) { struct file_priv *priv = container_of(work, struct file_priv, work); mutex_lock(&priv->buffer_mutex); atomic_set(&priv->data_pending, 0); memset(priv->data_buffer, 0, sizeof(priv->data_buffer)); mutex_unlock(&priv->buffer_mutex); }

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jason gunthorpejason gunthorpe68100.00%2100.00%
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static int tpm_open(struct inode *inode, struct file *file) { struct tpm_chip *chip = container_of(inode->i_cdev, struct tpm_chip, cdev); struct file_priv *priv; /* It's assured that the chip will be opened just once, * by the check of is_open variable, which is protected * by driver_lock. */ if (test_and_set_bit(0, &chip->is_open)) { dev_dbg(chip->pdev, "Another process owns this TPM\n"); return -EBUSY; } priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (priv == NULL) { clear_bit(0, &chip->is_open); return -ENOMEM; } priv->chip = chip; atomic_set(&priv->data_pending, 0); mutex_init(&priv->buffer_mutex); setup_timer(&priv->user_read_timer, user_reader_timeout, (unsigned long)priv); INIT_WORK(&priv->work, timeout_work); file->private_data = priv; get_device(chip->pdev); return 0; }

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jason gunthorpejason gunthorpe16196.41%250.00%
jarkko sakkinenjarkko sakkinen63.59%250.00%
Total167100.00%4100.00%


static ssize_t tpm_read(struct file *file, char __user *buf, size_t size, loff_t *off) { struct file_priv *priv = file->private_data; ssize_t ret_size; int rc; del_singleshot_timer_sync(&priv->user_read_timer); flush_work(&priv->work); ret_size = atomic_read(&priv->data_pending); if (ret_size > 0) { /* relay data */ ssize_t orig_ret_size = ret_size; if (size < ret_size) ret_size = size; mutex_lock(&priv->buffer_mutex); rc = copy_to_user(buf, priv->data_buffer, ret_size); memset(priv->data_buffer, 0, orig_ret_size); if (rc) ret_size = -EFAULT; mutex_unlock(&priv->buffer_mutex); } atomic_set(&priv->data_pending, 0); return ret_size; }

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jason gunthorpejason gunthorpe150100.00%2100.00%
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static ssize_t tpm_write(struct file *file, const char __user *buf, size_t size, loff_t *off) { struct file_priv *priv = file->private_data; size_t in_size = size; ssize_t out_size; /* cannot perform a write until the read has cleared either via tpm_read or a user_read_timer timeout. This also prevents splitted buffered writes from blocking here. */ if (atomic_read(&priv->data_pending) != 0) return -EBUSY; if (in_size > TPM_BUFSIZE) return -E2BIG; mutex_lock(&priv->buffer_mutex); if (copy_from_user (priv->data_buffer, (void __user *) buf, in_size)) { mutex_unlock(&priv->buffer_mutex); return -EFAULT; } /* atomic tpm command send and result receive */ out_size = tpm_transmit(priv->chip, priv->data_buffer, sizeof(priv->data_buffer)); if (out_size < 0) { mutex_unlock(&priv->buffer_mutex); return out_size; } atomic_set(&priv->data_pending, out_size); mutex_unlock(&priv->buffer_mutex); /* Set a timeout by which the reader must come claim the result */ mod_timer(&priv->user_read_timer, jiffies + (60 * HZ)); return in_size; }

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jason gunthorpejason gunthorpe186100.00%2100.00%
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/* * Called on file close */
static int tpm_release(struct inode *inode, struct file *file) { struct file_priv *priv = file->private_data; del_singleshot_timer_sync(&priv->user_read_timer); flush_work(&priv->work); file->private_data = NULL; atomic_set(&priv->data_pending, 0); clear_bit(0, &priv->chip->is_open); put_device(priv->chip->pdev); kfree(priv); return 0; }

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jason gunthorpejason gunthorpe8598.84%266.67%
jarkko sakkinenjarkko sakkinen11.16%133.33%
Total86100.00%3100.00%

const struct file_operations tpm_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .open = tpm_open, .read = tpm_read, .write = tpm_write, .release = tpm_release, };

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jason gunthorpejason gunthorpe76199.09%250.00%
jarkko sakkinenjarkko sakkinen70.91%250.00%
Total768100.00%4100.00%
Directory: drivers/char/tpm
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