proc_cmdline_auto_offset.h

#ifndef PROC_CMDLINE_AUTO_OFFSET_H_
#define PROC_CMDLINE_AUTO_OFFSET_H_
//声明
//////////////////////////////////////////////////////////////////////////
#include <linux/pid.h>
#include "ver_control.h"
//实现
//////////////////////////////////////////////////////////////////////////
#include "api_proxy.h"
MY_STATIC ssize_t g_arg_start_offset_proc_cmdline = 0; //mm_struct里arg_start的偏移位置
MY_STATIC bool g_init_arg_start_offset_success = false; //是否初始化找到过arg_start的偏移位置

typedef int(*t_get_task_proc_cmdline_addr)(struct task_struct *task, size_t * arg_start, size_t * arg_end);

MY_STATIC inline int init_proc_cmdline_offset(const char* proc_self_cmdline_content,
	t_get_task_proc_cmdline_addr o_get_task_proc_cmdline_addr) {

	int is_find_cmdline_offset = 0;
	size_t size = 4096;
	char *new_cmd_line_buf = NULL;
	struct task_struct * mytask = NULL;

	mytask = x_get_current();
	if (mytask == NULL) {
		return -EFAULT;
	}

	new_cmd_line_buf = (char*)kmalloc(size, GFP_KERNEL);
	g_init_arg_start_offset_success = true;
	for (g_arg_start_offset_proc_cmdline = -64; g_arg_start_offset_proc_cmdline <= 64; g_arg_start_offset_proc_cmdline += 1) {
		size_t arg_start = 0, arg_end = 0;
		printk_debug(KERN_INFO "get_task_proc_cmdline_addr g_arg_start_offset_proc_cmdline %zd\n", g_arg_start_offset_proc_cmdline);
		if (o_get_task_proc_cmdline_addr(mytask, &arg_start, &arg_end) == 0) {
			printk_debug(KERN_INFO "get_task_proc_cmdline_addr arg_start %p\n", (void*)arg_start);

			//读取每个+1的arg_start内存地址的内容
			if (arg_start > 0) {

				size_t read_size = 0;

				//开始读取物理内存
				memset(new_cmd_line_buf, 0, size);

				while (read_size < size) {
					//获取进程虚拟内存地址对应的物理地址
					size_t phy_addr;
					size_t pfn_sz;
					char *lpOutBuf;

#ifdef CONFIG_USE_PAGEMAP_FILE_CALC_PHY_ADDR
					struct file * pFile = open_pagemap(-1);
					printk_debug(KERN_INFO "open_pagemap %d\n", pFile);
					if (!pFile) { break; }

					phy_addr = get_pagemap_phy_addr(pFile, arg_start);

					close_pagemap(pFile);
#else
					pte_t *pte;
					phy_addr = get_task_proc_phy_addr(mytask, arg_start + read_size, (pte_t*)&pte);
#endif
					printk_debug(KERN_INFO "phy_addr:0x%zx\n", phy_addr);
					if (phy_addr == 0) {
						break;
					}


					pfn_sz = size_inside_page(phy_addr, ((size - read_size) > PAGE_SIZE) ? PAGE_SIZE : (size - read_size));
					printk_debug(KERN_INFO "pfn_sz:%zu\n", pfn_sz);


					lpOutBuf = (char*)(new_cmd_line_buf + read_size);
					read_ram_physical_addr(phy_addr, lpOutBuf, true, pfn_sz);
					read_size += pfn_sz;
				}

				printk_debug(KERN_INFO "new_cmd_line_buf:%s, len:%ld\n", new_cmd_line_buf, strlen(new_cmd_line_buf));

				if (strcmp(new_cmd_line_buf, proc_self_cmdline_content) == 0) {
					is_find_cmdline_offset = 1;
					break;
				}


			}
		}
	}

	kfree(new_cmd_line_buf);

	if (!is_find_cmdline_offset) {
		g_init_arg_start_offset_success = false;
		printk_debug(KERN_INFO "find cmdline offset failed\n");
		return -ESPIPE;
	}
	printk_debug(KERN_INFO "g_arg_start_offset_proc_cmdline:%zu\n", g_arg_start_offset_proc_cmdline);
	return 0;
}
#endif /* PROC_CMDLINE_AUTO_OFFSET_H_ */