add prctl constants on android #4531
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Some changes occurred in the Android module cc @maurer |
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I am not sure if those FreeBSD failures have anything to do with my change. The errors appear to be about a missing symbol that only appears in the FreeBSD path. |
src/unix/linux_like/android/mod.rs
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| #[cfg_attr(termux, link(name = "android-posix-semaphore"))] | ||
| extern "C" {} |
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On Android's bionic, there are some libc functions which are not supported, like sem_open, sem_close, and sem_unlink, which causes link failures when compiling anything with libc as a dependency.
On the Android terminal app Termux, there is a substitute port available as a separate library, which must be linked in explicitly.
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I think this is outside of the scope of libc. We are trying to reduce the number of libraries that get implicitly linked, and a third party library that isn't libc doesn't seem to make the cutoff.
Are the sem_* functions you mentioned not available via bionic in some cases?
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Fair enough. At the end of the day, it's easy enough to work around in downstream projects by linking in this third party lib via rustflags, etc. I've removed this.
The sem_* functions are not available at all. Or rather, they are "there", but are simply stubbed out, so anything that tries to use them just fails.
In the case of termux, for example, this would render python script that used multiprocessing broken.
bionic simply doesn't implement all of libc, so there are a few shims that are needed to supplement what's missing.
libc-test/build.rs
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| | "toupper" | "getpwuid_r" | "tmpfile" | "getpwnam" | "getpwuid" | "tcdrain" | ||
| | "cfgetispeed" | "cfgetospeed" | "cfsetispeed" | "cfsetospeed" | "tcgetattr" | ||
| | "tcsetattr" | "tcflow" | "tcflush" | "tcgetsid" | "tcsendbreak" | "cfmakeraw" | ||
| | "cfsetspeed" => true, |
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These don't seem relevant to the change here
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It's not strictly related, but tests for all these functions fail currently.
I split it out into another commit to make that clearer
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What circumstances make these fail? We have Android tests in CI and as far as I know this hasn't been a problem
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I'm not sure, to be honest; I didn't spend the time to dig into the failures. It could be something specific to termux.
I went ahead and removed these changes.
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Anything else I can do? |
Add all constants from bionic's `prctl.h` header https://android.googlesource.com/platform/bionic/+/7ac54f5c391bf3aeb9fec84a158939421fd8f505/libc/kernel/uapi/linux/prctl.h
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Add all constants from bionic's `prctl.h` header https://android.googlesource.com/platform/bionic/+/7ac54f5c391bf3aeb9fec84a158939421fd8f505/libc/kernel/uapi/linux/prctl.h (backport <rust-lang#4531>) (cherry picked from commit eb505fb)
Description
Add all constants from bionic's
prctl.hheaderSources
Checklist
libc-test/semverhave been updated*LASTor*MAXareincluded (see #3131)
cd libc-test && cargo test --target mytarget);especially relevant for platforms that may not be checked in CI
@rustbot label +stable-nominated