118 lines
2.7 KiB
C
Executable File
118 lines
2.7 KiB
C
Executable File
/*
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* sec_debug_first_kmsg.c
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*
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* Copyright (c) 2016 Samsung Electronics Co., Ltd
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* http://www.samsung.com
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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*/
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#include <linux/uaccess.h>
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#include <linux/proc_fs.h>
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#include <linux/sec_debug.h>
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#include <linux/kthread.h>
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extern void register_first_kmsg_hook_func(void (*)(const char *, size_t));
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static char *first_kmsg_base;
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static long first_kmsg_size;
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static int ready;
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static char *curr_ptr;
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size_t max;
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/* return true: in case ptr exceed buffer */
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static inline bool check_eob(char *buf, size_t size)
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{
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if (((size_t)buf + size) > max)
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return true;
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else
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return false;
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}
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/*
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* hook kernel log to (first_kmsg_base + curr_ptr)
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* until first_kmsg_base + first_kmsg_size(2MB)
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*/
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static void sec_debug_first_kmsg_hook(const char *buf, size_t size)
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{
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if (unlikely(check_eob(curr_ptr, size) != true )) {
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memcpy(curr_ptr, buf, size);
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curr_ptr += size;
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}
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return;
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}
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int __init sec_first_kmsg_init(void)
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{
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first_kmsg_size = sec_debug_get_buf_size(SDN_MAP_FIRST_KMSG);
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first_kmsg_base = (char *)phys_to_virt(sec_debug_get_buf_base(SDN_MAP_FIRST_KMSG));
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max = (size_t)(first_kmsg_base + first_kmsg_size);
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curr_ptr = first_kmsg_base;
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pr_info("%s: base: %p, size: 0x%lx\n", __func__, first_kmsg_base, first_kmsg_size);
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if (!first_kmsg_base || !first_kmsg_size)
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return 0;
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memset(first_kmsg_base, 0, first_kmsg_size);
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register_first_kmsg_hook_func(sec_debug_first_kmsg_hook);
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ready = 1;
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return 0;
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}
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early_initcall(sec_first_kmsg_init);
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static ssize_t sec_first_kmsg_read(struct file *file, char __user *buf,
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size_t len, loff_t *offset)
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{
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loff_t pos = *offset;
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ssize_t count;
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if (!ready) {
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pr_err("first_kmsg is not ready\n");
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return 0;
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}
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if (pos >= first_kmsg_size)
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return 0;
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count = min(len, (size_t)(first_kmsg_size - pos));
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if (copy_to_user(buf, first_kmsg_base + pos, count)) {
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pr_crit("%s: failed to copy to user\n", __func__);
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return -EFAULT;
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}
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*offset += count;
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return count;
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}
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static const struct file_operations first_kmsg_file_ops = {
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.owner = THIS_MODULE,
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.read = sec_first_kmsg_read,
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};
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static int __init sec_first_kmsg_late_init(void)
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{
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struct proc_dir_entry *entry;
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entry = proc_create("first_kmsg", S_IFREG | 0440,
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NULL, &first_kmsg_file_ops);
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if (!entry) {
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pr_err("%s: failed to create proc entry\n", __func__);
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return 0;
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}
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proc_set_size(entry, first_kmsg_size);
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pr_info("%s: success to create proc entry\n", __func__);
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return 0;
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}
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late_initcall(sec_first_kmsg_late_init);
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