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/* drivers/android/ram_console.c
*
* Copyright (C) 2007-2008 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 <linux/console.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/proc_fs.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/pstore_ram.h>
#include "ram_console.h"
static struct persistent_ram_zone *ram_console_zone;
static const char *bootinfo;
static size_t bootinfo_size;
static void
ram_console_write(struct console *console, const char *s, unsigned int count)
{
struct persistent_ram_zone *prz = console->data;
persistent_ram_write(prz, s, count);
}
static struct console ram_console = {
.name = "ram",
.write = ram_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
.index = -1,
};
void ram_console_enable_console(int enabled)
{
if (enabled)
ram_console.flags |= CON_ENABLED;
else
ram_console.flags &= ~CON_ENABLED;
}
static int __init ram_console_probe(struct platform_device *pdev)
{
struct ram_console_platform_data *pdata = pdev->dev.platform_data;
struct persistent_ram_zone *prz;
prz = persistent_ram_init_ringbuffer(&pdev->dev, true);
if (IS_ERR(prz))
return PTR_ERR(prz);
if (pdata) {
bootinfo = kstrdup(pdata->bootinfo, GFP_KERNEL);
if (bootinfo)
bootinfo_size = strlen(bootinfo);
}
ram_console_zone = prz;
ram_console.data = prz;
register_console(&ram_console);
return 0;
}
static struct platform_driver ram_console_driver = {
.driver = {
.name = "ram_console",
},
};
static int __init ram_console_module_init(void)
{
return platform_driver_probe(&ram_console_driver, ram_console_probe);
}
#ifndef CONFIG_PRINTK
#define dmesg_restrict 0
#endif
static ssize_t ram_console_read_old(struct file *file, char __user *buf,
size_t len, loff_t *offset)
{
loff_t pos = *offset;
ssize_t count;
struct persistent_ram_zone *prz = ram_console_zone;
size_t old_log_size = persistent_ram_old_size(prz);
const char *old_log = persistent_ram_old(prz);
char *str;
int ret;
if (dmesg_restrict && !capable(CAP_SYSLOG))
return -EPERM;
/* Main last_kmsg log */
if (pos < old_log_size) {
count = min(len, (size_t)(old_log_size - pos));
if (copy_to_user(buf, old_log + pos, count))
return -EFAULT;
goto out;
}
/* ECC correction notice */
pos -= old_log_size;
count = persistent_ram_ecc_string(prz, NULL, 0);
if (pos < count) {
str = kmalloc(count, GFP_KERNEL);
if (!str)
return -ENOMEM;
persistent_ram_ecc_string(prz, str, count + 1);
count = min(len, (size_t)(count - pos));
ret = copy_to_user(buf, str + pos, count);
kfree(str);
if (ret)
return -EFAULT;
goto out;
}
/* Boot info passed through pdata */
pos -= count;
if (pos < bootinfo_size) {
count = min(len, (size_t)(bootinfo_size - pos));
if (copy_to_user(buf, bootinfo + pos, count))
return -EFAULT;
goto out;
}
/* EOF */
return 0;
out:
*offset += count;
return count;
}
static const struct file_operations ram_console_file_ops = {
.owner = THIS_MODULE,
.read = ram_console_read_old,
};
static int __init ram_console_late_init(void)
{
struct proc_dir_entry *entry;
struct persistent_ram_zone *prz = ram_console_zone;
if (!prz)
return 0;
if (persistent_ram_old_size(prz) == 0)
return 0;
entry = create_proc_entry("last_kmsg", S_IFREG | S_IRUGO, NULL);
if (!entry) {
printk(KERN_ERR "ram_console: failed to create proc entry\n");
persistent_ram_free_old(prz);
return 0;
}
entry->proc_fops = &ram_console_file_ops;
entry->size = persistent_ram_old_size(prz) +
persistent_ram_ecc_string(prz, NULL, 0) +
bootinfo_size;
return 0;
}
late_initcall(ram_console_late_init);
postcore_initcall(ram_console_module_init);
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