为什么在静态链接的可执行文件中有全局偏移表和过程链接表? [英] Why are there global offset tables and procedure linkage tables in statically linked executables?

问题描述

我已经完成了大量有关动态链接器重定位和位置无关代码的阅读，其中包括过程链接表和全局偏移量表.我不明白为什么静态链接的可执行文件需要PLT和GOT.我在ubuntu x86_64机器上编译了一个hello world程序，当我用readelf -S转储节头时，它会显示PLT和GOT节.

I've done a bunch of reading on dynamic linker relocations and position independent code including procedure linkage tables and global offset tables. I don't understand why a statically linked executable needs a PLT and GOT. I compiled a hello world program on my ubuntu x86_64 machine and when I dump the section headers with readelf -S it shows PLT and GOT sections.

我还创建了一个共享库，它具有一个简单的增量函数，该函数使用gcc -shared编译而没有-fpic，并且还看到了PLT和GOT部分.我也没想到这一点.

I also created a shared library with a simple increment function that I compiled with gcc -shared without -fpic and I also see PLT and GOT sections. I didn't expect this either.

推荐答案

我不明白为什么静态链接的可执行文件需要PLT和GOT.

I don't understand why a statically linked executable needs a PLT and GOT.

不是.

我在ubuntu x86_64机器上编译了一个hello world程序，当我用readelf -S转储节头时，它会显示PLT和GOT节.

I compiled a hello world program on my ubuntu x86_64 machine and when I dump the section headers with readelf -S it shows PLT and GOT sections.

这是实施的偶然事件.这些部分来自crt1.o，并且没有单独的crt1s.o用于全静态链接，因此您最终从那里获得.plt和.got条目.

This is an accident of implementation. The sections come from crt1.o, and there isn't a separate crt1s.o for fully-static linking, so you end up with .plt and .got entries from there.

您可以删除这些部分，二进制文件仍将起作用:

You can strip these sections, and the binary will still work:

objcopy -R.got -R.plt a.out a.out2

注意:请勿剥离.rela.plt，因为实现IFUNC仍需要该部分.

Note: do not strip .rela.plt, as that section is still needed to implement IFUNCs.

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