1 Linux記憶體洩漏檢測工具Valgrind

Valgrind簡介

        Valgrind是一套Linux下，開放原始碼（GPL V2）的模擬除錯工具的集合。Valgrind由核心（core）以及基於核心的其他除錯工具組成。核心類似於一個框架（framework），它模擬了一個CPU環境，並提供服務給其他工具；而其他工具則類似於外掛 (plug-in)，利用核心提供的服務完成各種特定的記憶體除錯任務。

Valgrind是一套Linux下，開放原始碼（GPL V2）的模擬除錯工具的集合。Valgrind由核心（core）以及基於核心的其他除錯工具組成。核心類似於一個框架（framework），它模擬了一個CPU環境，並提供服務給其他工具；而其他工具則類似於外掛 (plug-in)，利用核心提供的服務完成各種特定的記憶體除錯任務。

Valgrind用法

valgrind [options] prog-and-args [options]: 常用選項，適用於所有Valgrind工具。

- tool=<name> 最常用的選項。執行 valgrind中名為toolname的工具。預設memcheck。
h –help 顯示幫助資訊。
-version 顯示valgrind核心的版本，每個工具都有各自的版本。
q –quiet 安靜地執行，只打印錯誤資訊。
v –verbose 更詳細的資訊, 增加錯誤數統計。
-trace-children=no|yes 跟蹤子執行緒? [no]
-track-fds=no|yes 跟蹤開啟的檔案描述？[no]
-time-stamp=no|yes 增加時間戳到LOG資訊? [no]
-log-fd=<number> 輸出LOG到描述符檔案 [2=stderr]
-log-file=<file> 將輸出的資訊寫入到filename.PID的檔案裡，PID是執行程式的進行ID
-log-file-exactly=<file> 輸出LOG資訊到 file
-log-file-qualifier=<VAR> 取得環境變數的值來做為輸出資訊的檔名。 [none]
-log-socket=ipaddr:port 輸出LOG到socket ，ipaddr:port
LOG資訊輸出
-xml=yes 將資訊以xml格式輸出，只有memcheck可用
-num-callers=<number> show <number> callers in stack traces [12]
-error-limit=no|yes 如果太多錯誤，則停止顯示新錯誤? [yes]
-error-exitcode=<number> 如果發現錯誤則返回錯誤程式碼 [0=disable]
-db-attach=no|yes 當出現錯誤，valgrind會自動啟動偵錯程式gdb。[no]
-db-command=<command> 啟動偵錯程式的命令列選項[gdb -nw %f %p]
適用於Memcheck工具的相關選項：
-leak-check=no|summary|full 要求對leak給出詳細資訊? [summary]
-leak-resolution=low|med|high how much bt merging in leak check [low]
-show-reachable=no|yes show reachable blocks in leak check? [no]

安裝valgrind

[email protected]:~/test$ sudo apt-get install valgrind

測試程式碼

[email protected]:~/test$ cat testcode.c 
#include <stdlib.h>
int *fun()
{
int *p = malloc(10 * sizeof(int));
p[10] =0 ;  //error 1
return p;
}
int main()
{
int *ptr = NULL;
ptr = fun();
//free(c);  //error 2
ptr = NULL;
return 0;
}
編譯：
[email protected]:~/gcc testcode.c -o main
[email protected]:~/test$ ls

main  testcode.c

valgrind使用

[email protected]:~/test$ valgrind --tool=memcheck  --leak-check=full ./main

報告

==77673== Memcheck, a memory error detector
==77673== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==77673== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==77673== Command: ./main
==77673== 
==77673== Invalid write of size 4
==77673==    at 0x400544: fun (in /home/azheng/test/main)
==77673==    by 0x400566: main (in /home/azheng/test/main)
==77673==  Address 0x5204068 is 0 bytes after a block of size 40 alloc'd
==77673==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==77673==    by 0x400537: fun (in /home/azheng/test/main)
==77673==    by 0x400566: main (in /home/azheng/test/main)
==77673== 
==77673== 
==77673== HEAP SUMMARY:
==77673==     in use at exit: 40 bytes in 1 blocks
==77673==   total heap usage: 1 allocs, 0 frees, 40 bytes allocated
==77673== 
==77673== 40 bytes in 1 blocks are definitely lost in loss record 1 of 1
==77673==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==77673==    by 0x400537: fun (in /home/azheng/test/main)
==77673==    by 0x400566: main (in /home/azheng/test/main)
==77673== 
==77673== LEAK SUMMARY:
==77673==    definitely lost: 40 bytes in 1 blocks
==77673==    indirectly lost: 0 bytes in 0 blocks
==77673==      possibly lost: 0 bytes in 0 blocks
==77673==    still reachable: 0 bytes in 0 blocks
==77673==         suppressed: 0 bytes in 0 blocks
==77673== 
==77673== For counts of detected and suppressed errors, rerun with: -v
==77673== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)

重新修改程式碼後，進行記憶體檢查

[email protected]:~/test$ valgrind --tool=memcheck  --leak-check=yes --show-reachable=yes ./main 
==77813== Memcheck, a memory error detector
==77813== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==77813== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==77813== Command: ./main
==77813== 
==77813== 
==77813== HEAP SUMMARY:
==77813==     in use at exit: 0 bytes in 0 blocks
==77813==   total heap usage: 1 allocs, 1 frees, 40 bytes allocated
==77813== 
==77813== All heap blocks were freed -- no leaks are possible
==77813== 
==77813== For counts of detected and suppressed errors, rerun with: -v
==77813== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

說明

Invalid write of size 4：表示陣列越界寫了4位元組

40 bytes in 1 blocks：表示因程式退出而發生記憶體洩露40位元組

2 Windows記憶體洩漏檢測工具VLD

Visual Leak Detector

下載連結：


在Visual C++ IDE的"工具"→"選項"→"專案和解決方案"→"VC++ 目錄"，"包含檔案"增加VLD的"\include"路徑，"庫檔案"增加VLD的"\lib\Win32"路徑，另外動態庫"\bin\Win32"路徑在安裝時已經新增到環境變數裡面了，若是未新增，則需要手動拷貝"\bin\Win32"下的檔案到工程Debug目錄。

新增#include "vld.h"

3 CppCheck

        Windows版本不好用，Linux還可以。

4 Cpplint

程式碼規範檢查

[email protected]:~$ cat test/testcode.c 
#include <stdlib.h>
int *fun()
{
int *x = malloc(10 * sizeof(int));
x[10] =0 ; //error
}
int main()
{
int *c = NULL;
c = fun();
return 0;
}

[email protected]:~$ cppcheck test/testcode.c 

Checking test/testcode.c...
[test/testcode.c:5]: (error) Array 'x[10]' accessed at index 10, which is out of bounds.

[test/testcode.c:6]: (error) Memory leak: x

[email protected]:~$ cpplint-1.3.0/cpplint.py test/testcode.c 
test/testcode.c:0:  No copyright message found.  You should have a line: "Copyright [year] <Copyright Owner>"  [legal/copyright] [5]
test/testcode.c:3:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
test/testcode.c:4:  Tab found; better to use spaces  [whitespace/tab] [1]
test/testcode.c:5:  Tab found; better to use spaces  [whitespace/tab] [1]
test/testcode.c:5:  At least two spaces is best between code and comments  [whitespace/comments] [2]
test/testcode.c:5:  Should have a space between // and comment  [whitespace/comments] [4]
test/testcode.c:5:  Missing spaces around =  [whitespace/operators] [4]
test/testcode.c:5:  Extra space before last semicolon. If this should be an empty statement, use {} instead.  [whitespace/semicolon] [5]
test/testcode.c:9:  { should almost always be at the end of the previous line  [whitespace/braces] [4]
test/testcode.c:10:  Tab found; better to use spaces  [whitespace/tab] [1]
test/testcode.c:11:  Tab found; better to use spaces  [whitespace/tab] [1]
test/testcode.c:12:  Tab found; better to use spaces  [whitespace/tab] [1]
Done processing test/testcode.c
Total errors found: 12