glibc库版本查看和动态库增加可执行属性

最新推荐文章于 2025-06-12 18:20:40 发布

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最新推荐文章于 2025-06-12 18:20:40 发布 · 1.2k 阅读

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#linux #glibc #动态库

本文介绍了如何查看Linux系统中的glibc库版本，以及如何通过修改动态库使其具备可执行属性。重点讲解了__libc_main函数的作用和如何在库文件中插入版本信息。

glibc库版本查看和动态库增加可执行属性

文章目录

- glibc库版本查看和动态库增加可执行属性

1.查看当前glibc版本

查看当前系统的glibc版本:

#/lib/libc.so.6
#/lib/x86-64-linux/libc.so.6
➜  ~ /lib64/libc.so.6
GNU C Library (GNU libc) stable release version 2.17, by Roland McGrath et al.
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.8.5 20150623 (Red Hat 4.8.5-44).
Compiled on a Linux 3.10.0 system on 2021-02-08.
Available extensions:
        The C stubs add-on version 2.1.2.
        crypt add-on version 2.1 by Michael Glad and others
        GNU Libidn by Simon Josefsson
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
        RT using linux kernel aio
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

# 因为ldd命令也是glibc提供的，所以也能查看
➜  ~ ldd --version
ldd (GNU libc) 2.17
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.

为什么这个库可以直接run呢？原来在libc的代码中有一点小手脚:

Makerules:708:
# Give libc.so an entry point and make it directly runnable itself.
LDFLAGS-c.so += -e __libc_main

查看__libc_main函数的实现

/* Copyright (C) 1992-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include "version.h"