Linux/C++:获取用户目录而不泄漏

Question

我错误地认为以下代码中有内存泄漏只是试图读取用户的主目录？

static std::string getHomeDir()
{
    struct passwd *pw = getpwuid(getuid());
    std::string res( pw->pw_dir);
    endpwent();
    return res;
}

valgrind抱怨:

==32757== 160 (40 direct, 120 indirect) bytes in 1 blocks are definitely lost in loss record 42 of 48
==32757==    at 0x402BB7A: malloc (in /usr/lib/valgrind/vgpreload_memcheck-x86-linux.so)
==32757==    by 0x456E84E: nss_parse_service_list (nsswitch.c:678)
==32757==    by 0x456EFC9: __nss_database_lookup (nsswitch.c:175)
==32757==    by 0x4A8E168: ???
==32757==    by 0x4A8FB5C: ???
==32757==    by 0x4525FA6: getpwuid_r@@GLIBC_2.1.2 (getXXbyYY_r.c:256)
==32757==    by 0x45258ED: getpwuid (getXXbyYY.c:117)
==32757==    by 0x805AD56: getHomeDir() (ConfigReader.cpp:73)

(另外,作为旁注:man getpwuid显示一个示例程序,也会泄漏相同数量的内存......)

(对于那些想要与他们的linux进行比较的人:

uname -a给Linux reference 3.5.0-47-generic #71-Ubuntu SMP Tue Feb 18 23:59:30 UTC 2014 i686 athlon i686 GNU/Linux...基本上是Ubuntu 12.10

Answer 1

这是一个已知的错误:

nss_parse_service_list泄漏了很少的内存

它被认为是"WONTFIX",其注释表明"内存被分配一次以保持全局状态,并且通常不会被释放".