Bug 214047
| Summary: | libcap 2.52: Clang fails to build shared objects as runnable binaries | ||
|---|---|---|---|
| Product: | Tools | Reporter: | Johan Herland (jherland) |
| Component: | libcap | Assignee: | Andrew G. Morgan (morgan) |
| Status: | RESOLVED CODE_FIX | ||
| Severity: | normal | CC: | morgan |
| Priority: | P1 | ||
| Hardware: | x86-64 | ||
| OS: | Linux | ||
| Kernel Version: | N/A | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
Thanks for this bug report. To date, I've never actually looked into supporting clang. However, this bug suggests it was mostly working before this latest release, so I'll set up a testing environment and try to figure out how to make it work. While I figure out how to set up clang builds, you might like to try replacing '--entry=__so_start' with '-Wl,-e,__so_start'. Please see this commit: https://git.kernel.org/pub/scm/libs/libcap/libcap.git/commit/?id=6dea1813f269f9c03cea226fffdd75670c70ea01 Reopen if that doesn't address your needs. Can confirm that your commit resolves this issue for us as well. Appreciate the quick turnaround, and thanks for your time! |
When upgrading libcap from 2.51 to 2.52, our clang build started complaining with: ``` /toolchain/host-llvm-10.0.1-x86_64-linux-1/bin/objcopy --dump-section .interp=/dev/stdout empty > loader.txt /toolchain/host-llvm-10.0.1-x86_64-linux-1/bin/objcopy: error: 'empty': Permission denied ``` This problem seems to be fixed by changing this rule in `libcap/Makefile`: ``` loader.txt: empty $(OBJCOPY) --dump-section .interp=/dev/stdout $< > $@ ``` to this: ``` loader.txt: empty $(OBJCOPY) --dump-section .interp=$@ $< ``` However, that only uncovers the next build error: ``` clang-10: error: unsupported option '--entry=__so_start' ``` which I suspect is related to this section in the same `libcap/Makefile`: ``` # The linker magic needed to build a dynamic library as independently # executable MAGIC=--entry=__so_start ``` Any ideas on how to fix this for clang? Or how to easily disable this feature when building with clang?