core: support launching statically linked executables #1254
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nyh
requested changes
Sep 19, 2023
This patch enhances the dynamic linker to support launching statically linked executables. The dynamically linked executables or shared libraries are typically launched by calling a "main" function which is exported and can be resolved using the ELF symbol table. The statically linked executables do not export such symbol and instead must be launched by jumping to the ELF entry point specified in the header. To that end this patch implements new functions - run_entry_point() - specific for each architecture - x86_64 and aarch64 which fundamentally do similar thing - put argc, argv, environment variables and auxiliary vector on stack and jump to the elf entry point. In addition this patch enhances other parts of the dynamic linker logic to do things a little bit differently for statically linked executables: - do not relocate as the executable comes with its own code that does this - do not call INIT and FINI function for the same reason as above - do not try to load dependant libraries as they would be none This patch also adds augment_auxv() to add extra auxiliary vector entries needed by statically linked executables to bootstrap themselves In addition, this 2nd version of the PR renames the method is_statically_linked() to is_statically_linked_executable() and fixes it by identifying if an ELF is not a shared library. So it should fix the "liblua.so" problem reported by Nadav. Signed-off-by: Waldemar Kozaczuk <[email protected]>
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This patch enhances the dynamic linker to support launching statically linked executables.
The dynamically linked executables or shared libraries are typically launched by calling a "main" function which is exported and can be resolved using the ELF symbol table. The statically linked executables do not export
such symbols and instead must be launched by jumping to the ELF entry point specified in the header. To that end this patch implements new functions -
run_entry_point()- specific for each architecture - x86_64 and aarch64 which fundamentally do a similar thing - putargc,argv, environment variables, and auxiliary vector on the stack and jump to the elf entry point.In addition, this patch enhances other parts of the dynamic linker logic to do things a little bit differently for statically linked executables:
This patch also adds augment_auxv() to add the extra auxiliary vector entries needed by statically linked executables to bootstrap themselves
In addition, this 2nd version of the PR renames the method
is_statically_linked()tois_statically_linked_executable()and fixes it by identifying if an ELF is not a shared library. So it should fix the "liblua.so" problem reported by Nadav.Closes #1140