如何抑制来自 gpgme 的 valgrind 警告？

Posted 2023-03-06

【中文标题】如何抑制来自 gpgme 的 valgrind 警告？

【英文标题】：How to suppress valgrind warnings from gpgme?

【发布时间】：2018-02-09 19:07:56

【问题描述】：

我正在尝试在我的代码中使用 GPGME 来验证一些签名。然而，简单地初始化和释放 GPGME 上下文会导致 valgrind 发出大量警告。

例如：

#include <gpgme.h>

int main() 
    gpgme_check_version(NULL);
    gpgme_ctx_t my_ctx;
    gpgme_error_t gpg_err;

    gpg_err = gpgme_new(&my_ctx);

    gpgme_release(my_ctx);

    return 0;

用gcc -lgpgme -lassuan -lgpg-error main.c 编译它，然后在valgrind 下运行它。从valgrind -v ./a.out 来看，这段代码似乎启动了 6 个不同的进程。我已经复制了相关的警告信息：

==19158== Warning: invalid file descriptor 1024 in syscall close()
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)
==19158== Warning: invalid file descriptor 1025 in syscall close()
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)
==19158== Warning: invalid file descriptor 1026 in syscall close()
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)
==19158== Warning: invalid file descriptor 1027 in syscall close()
==19158==    Use --log-fd=<number> to select an alternative log fd.
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)
==19158== Warning: invalid file descriptor 1028 in syscall close()
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)
==19158== Warning: invalid file descriptor 1029 in syscall close()
==19158==    at 0x558DBC4: close (in /usr/lib/libc-2.26.so)
==19158==    by 0x4E65DF8: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E66D65: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6736B: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56572: gpgme_get_engine_info (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E56C87: ??? (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x4E6838F: gpgme_new (in /usr/lib/libgpgme.so.11.19.0)
==19158==    by 0x10880B: main (in /home/thedoctor/Programming/gpgmetest/mytest)

总共对 6 个不同的进程重复了完全相同的一组警告。似乎 GPGME 试图关闭一些不属于自己的文件描述符。

我的问题有两个：

我是否使用了 gpgme API 错误？我还有什么需要做的吗？ 如果 API 的使用正确，如何从 valgrind 抑制这些警告？

我似乎无法让 valgrind 对这些警告进行抑制。运行 valgrind --gen-suppressions=all -v ./a.out 不会在输出中显示任何抑制。我想这是因为这些是警告而不是真正的错误。我尝试自己写一个抑制，但我不确定应该是什么类型。通常，当我不得不写抑制时，它们是针对Memcheck:Leak。但这些警告属于哪一类？

编辑：这是我尝试写的一个抑制：

    gpgme-leak-fd
    fun:close
    ...
    fun:gpgme_new

编辑 2：我试图提供赏金，但它已过期。如果你对此有一个有效的答案，我提供 100 个代表的赏金。

【问题讨论】：

你可以写你自己的压制。见wiki.wxwidgets.org/Valgrind_Suppression_File_Howto

就像我提到的，我已经尝试过这样做。但 valgrind 似乎并不尊重这些。可能是因为我的语法不正确

【参考方案1】：

以下是 Dan McGee 编写的 GPGME 规则，摘自here：

   gpgme-static-get-engine-info
   Memcheck:Leak
   fun:malloc
   ...
   fun:gpgme_get_engine_info


   gpgme-static-set-engine-info
   Memcheck:Leak
   fun:malloc
   ...
   fun:_gpgme_set_engine_info
   fun:gpgme_set_engine_info


   gpgme-static-set-locale
   Memcheck:Leak
   fun:malloc
   fun:strdup
   fun:gpgme_set_locale
 

【讨论】：

正如我在帖子中提到的，我试图抑制的不是内存泄漏，而是无效的文件描述符警告。