Turn -- bring it and use it: share a gadget for checking memory leaks

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                <p><span style="color:#ffbb66;"><strong>【 Function description 】</strong></span></p> 

【 Function description 】

        stay The embedded During the development of system application , Memory leakage is a serious and troublesome problem .  Yes, of course , There are many professional tools and software to check memory leaks , What I use more is memwatch, valgrind.

        These tools are mainly used to check memory leaks in the development process . however , If all the programs are developed , Start Integration testing when , It is still found that system resources continue to decrease , So how to deal with it ？

        The gadgets provided here are used to deal with this situation ： Can monitor what you suspect 、 System resources used by those processes that may have memory leaks .

        Especially when a system is developed by more than one person 、 A situation consisting of multiple processes , If there is a resource leak , Who should you suspect first ？ Who should check whether there is a problem with their own program first ？ Wrangling often happens , The estrangement between small partners has also planted seeds in the subconscious .

        here , The data output from the monitoring program is the most useful ！

 

 

【 Test environment 】

1. x86 System

    I was in  Ubuntu16.04 Under test , Use the system gcc compiler .

2. Embedded system

    Just replace the compiler with the corresponding cross compiler .

 

【 The code download 】

1. Network disk

    https://pan.baidu.com/s/1yNrjQ6var8xokAJWEsFYFw  

    passwd:uqbh

 

/**
 * @brief：　 This gadget is used to monitor the resource usage of some processes in the system ,
 *			 It can be used to check whether there is memory leak in the program .
 *　
 *　@author:  WeChat  captain5780
 * @email:  [email protected]
 *
 * @note：　./memory_trace < Process name １> < Process name ２> < Process name ３>
 */
 
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
 
#define TRACE_ITEM_NUM		4
#define PROCESS_MAX			20
#define PROCESS_NAME_LEN	128
#define BUF_LEN				512
 
//  Name of the resource to be monitored 
char *TraceItem[TRACE_ITEM_NUM] = 
	{"VmSize", "VmRSS", "VmStk", "VmData"};
 
//  Save the name of the process to be monitored 
char *ProcessList[PROCESS_MAX];
 
//  Print a message , It can be used in actual projects  zlog  Wait for logging tools to record to the file system .
static void log_msg(const char *msg)
{
	printf("%s", msg);
}
 
int main(int argc, char *argv[])
{
	//  Check the maximum number of monitored processes 
	if (argc >= PROCESS_MAX) {
		printf("too many process \n");
		exit(-1);
	}
 
	//  Extract the process name passed in by the command line parameters , Save in 　ProcessList　 in .
	int i, k, count;
	for (i = 0, count = 0; i < argc - 1; i++) {
		count++;
		ProcessList[i] = (char *)malloc(PROCESS_NAME_LEN);
		memset(ProcessList[i], 0, PROCESS_NAME_LEN);
		sprintf(ProcessList[i], "%s", argv[i + 1]);
	}
 
	time_t rawtime;
	struct tm *timeinfo;
	char *buf = (char *)malloc(BUF_LEN);
 
	while (1) {
		//  Record the current time 
		time(&rawtime);
		timeinfo = localtime(&rawtime);
		memset(buf, 0, BUF_LEN);
		sprintf(buf, "\n[%02d:%02d:%02d] \n",
				timeinfo->tm_hour, 
				timeinfo->tm_min, 
				timeinfo->tm_sec);
		log_msg(buf);
 
		//　 this for The loop is used to obtain the resource usage of the monitoring process 
		for (i = 0; i < count; i++) {
			memset(buf, 0, BUF_LEN);
			sprintf(buf, "[%s] \n", ProcessList[i]);
			log_msg(buf);
 
			for (k = 0; k < TRACE_ITEM_NUM; k++) {
				memset(buf, 0, BUF_LEN);
				//  Acquisition process ID Number :  Execute system commands , Then read the output .
				sprintf(buf, 
				    "ps -aux | grep %s | grep -v grep | awk '{print $2}'", 
				    ProcessList[i]);
				FILE *fp = popen(buf, "r");
				if (NULL == fp) {
					printf("popen failed! \n");
					continue;
				}
 
				char line[128] = { 0 };
				fgets(line, 128, fp);
				int len = strlen(line);
				if (*(line + len - 1) == '\n')
					*(line + len - 1) = 0;
				pclose(fp); 
 
				//  According to the process ID Number , Get the stack information of the process .
				memset(buf, 0, BUF_LEN);
				sprintf(buf, 
						"cat /proc/%s/status | grep %s | grep -v grep", 
						line, TraceItem[k]);
				
				fp = popen(buf, "r");
				if (NULL == fp) {
					printf("popen failed! \n");
					continue;
				}
				fgets(line, 128, fp);
				pclose(fp);
				log_msg(line);   //  Record it in the Journal 
			}
		}
 
		//  Get the idle resource information of the system 
		memset(buf, 0, BUF_LEN);
		sprintf(buf, "free | grep Mem: | grep -v grep");
		FILE *fp = popen(buf, "r");
		if (NULL == fp) {
			printf("popen failed! \n");
			continue;
		}
 
		char line[128] = { 0 };
		fgets(line, 128, fp);
		pclose(fp);
		log_msg(line);
 
		sleep(5);    //  At intervals 
	}
 
	//  Release 　malloc  Allocated heap space 
	free(buf);
 
	for (i = 0; i < PROCESS_MAX; i++) {
		if (ProcessList[i])
			free(ProcessList[i]);
	}
 
	return 0;
}

3. Printout

    The function of this tool is actually very simple , It is to call system instructions to monitor the system resources occupied by processes .

 

    Specifically, continuous output ：/proc/[pid]/status The content of . This document contains 4 Key indicators , Here is a brief list of , The specific meaning can be searched .

    VmSize(KB): The size of virtual memory used by the process .

    VmRSS(KB): Part of the process that resides in physical memory , Not swapped to hard disk .

    VmStk(KB): The size of the stack used by the process .

    VmData(KB): The size of the process data segment .

 

【 Why write this gadget 】

  I wrote an Internet of things gateway product before , These include 3 It's a big module , And it is the responsibility of different people , What is fatal is ： this 3 I'm alone in Japan , One in Taiwan , And then there's us .

 

    During the integration test, it is found that the system resources continue to decrease , And there is no rule . Because there are many interactions between processes , Maybe it's just when some specific execution logic is triggered , Memory leakage and other situations may occur .

 

    In order to find out the culprit , So I wrote this gadget . About 2 Time of day , It soon located the source of the problem .

 

【 Problems you may encounter 】

1. System instructions

    Several system instructions are used in the program ：proc, grep, awk, free.

    The output format of these instructions may be different in different embedded systems , If there is a problem with the output of running this tool directly , Then you need to adjust the instruction parsing part of the code .

 

2. How to adjust

    for example ： This instruction is used in the code according to Process name obtain process ID：ps -aux | grep %s | grep -v grep | awk '{print $2}’

    about ps Instructions , It may not be necessary in your system -aux attribute .

    about awk Instructions , The self-contained information extracted in your system may be '{print $1}’.

    True knowledge comes from practice ！

 

【END】

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2. If there are mistakes in the article , Or hope to communicate 、 Discuss relevant contents , Welcome to contact me .

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