问题
I want to compile a shared library with an .interp segment.
#include <stdio.h>
int foo(int argc, char** argv) {
printf("Hello, world!\n");
return 0;
}
I'm using the following commands.
gcc -c -o test.o test.c
ld --dynamic-linker=blah -shared -o test.so test.o
I end up without an INTERP segment, as if I never passed the --dynamic-linker=blah option. Check with readelf -l test.so. When building an executable, the linker processes the option correctly and puts an INTERP segment in the program header. How to do I make it work for shared libraries too?
回答1:
ld doesn't include a .interp section if -shared is used, as @MichaelDillon already said. You can however provide this section yourself.
const char interp_section[] __attribute__((section(".interp"))) = "/path/to/dynamic/linker";
The line above will save the string "/path/to/dynamic/linker" in the .interp section using GCC attributes.
If you're trying to build a shared object that's also executable by itself, check this question out. It has a more comprehensive description of the process.
回答2:
The INTERP segment only goes into binaries which need to load the ELF interpreter (ld.so) in the first place. A shared library has no INTERP segment because the ELF interpreter is already loaded before the shared library is loaded.
回答3:
In most linux systems the ldconfig is run at every system boot and it looks definitions in /etc/ld.so.conf for looking in directories that have shared libraries. In the file /etc/ld.so.cache there are mappings for shared libraries sonames and the library full path. Consider reading this article: http://grahamwideman.wordpress.com/2009/02/09/the-linux-loader-and-how-it-finds-libraries/#comment-164
来源：https://stackoverflow.com/questions/4488937/how-to-set-the-dynamic-linker-path-for-a-shared-library