vagrind检测内存泄露

今天想检测自己写的一段代码有没有内存泄露，于是想到了googleperf和vagrind，对比了一下，vagrind能检测出一处内存泄露，而googleperf却没有，不知道是什么原因，这两个工具的原理也不太一样，vagrind的在自己的模拟环境下跑的，而googleperf是通过链接自己的tcmalloc的方式来实现。

vagrind检测内存泄露的方法是这样的：

方法

valgrind --leak-check=full ./sx_utils

结果

==16466== Memcheck, a memory error detector==16466== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.==16466== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info==16466== Command: ./sx_utils==16466== ==16466== ==16466== HEAP SUMMARY:==16466==     in use at exit: 776 bytes in 26 blocks==16466==   total heap usage: 57 allocs, 31 frees, 30,560 bytes allocated==16466== ==16466== 360 (240 direct, 120 indirect) bytes in 10 blocks are definitely lost in loss record 8 of 8==16466==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)==16466==    by 0x4E9DF77: CRYPTO_malloc (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.2)==16466==    by 0x4F4B869: BUF_MEM_new (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.2)==16466==    by 0x4F4CEC8: ??? (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.2)==16466==    by 0x4F4BE91: BIO_set (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.2)==16466==    by 0x4F4BF01: BIO_new (in /usr/lib/x86_64-linux-gnu/libcrypto.so.1.0.2)==16466==    by 0x400CE5: sx_base64_encode (sx_utils.c:54)==16466==    by 0x400EEC: main (sx_utils.c:95)==16466== ==16466== LEAK SUMMARY:==16466==    definitely lost: 240 bytes in 10 blocks==16466==    indirectly lost: 120 bytes in 10 blocks==16466==      possibly lost: 0 bytes in 0 blocks==16466==    still reachable: 416 bytes in 6 blocks==16466==         suppressed: 0 bytes in 0 blocks==16466== Reachable blocks (those to which a pointer was found) are not shown.==16466== To see them, rerun with: --leak-check=full --show-leak-kinds=all==16466== ==16466== For counts of detected and suppressed errors, rerun with: -v==16466== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

分析

上面我们能够看到，sx_utils.c文件的54行BIO_new的一个东西中，BUF_MEM_new的内存没有释放，通过查看代码，的确是这样的，释放掉了就好了。