Use more constants and functions from libc #368
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Oh whoops, forgot to use libc's memfd :) |
| @@ -1096,7 +1099,7 @@ fn create_shmem(name: CString, length: usize) -> c_int { | |||
| #[cfg(all(feature = "memfd", target_os = "linux"))] | |||
| fn create_shmem(name: CString, length: usize) -> c_int { | |||
| unsafe { | |||
| let fd = memfd_create(name.as_ptr(), libc::MFD_CLOEXEC as usize); | |||
| let fd = libc::memfd_create(name.as_ptr(), libc::MFD_CLOEXEC); | |||
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Oh hmm, glibc support was only added in 2.27. Not sure what the glibc policy of ipc-channel is.
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FWIW I think the old call was incorrect, since it passed in a usize but the syscall is a cint: https://github.com/torvalds/linux/blob/4d939780b70592e0f4bc6c397e52e518f8fb7916/mm/memfd.c#L332
This worked presumably because of little-endianness, but it wasn't correct as far as I can tell.
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Looks like glibc 2.27 came out in 2018: https://sourceware.org/glibc/wiki/Release/2.27.
| // determined by CMSG_SPACE. (On Linux this would the same as CMSG_ALIGN, but that isn't | ||
| // exposed by libc. CMSG_SPACE(0) is the portable version of that.) | ||
| (cmsg.cmsg_len() - CMSG_SPACE(0) as size_t) / mem::size_of::<c_int>() |
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If CMSG_ALIGN is not in libc we should add it.
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CMSG_ALIGN isn't portable, though, which is the challenge. CMSG_SPACE(0) should always be the same.
I've been trying to port ipc-channel to illumos for use in a downstream project, and I found that this code was using a local copy of several functions and constants that are in libc. In particular: * Some of the `CMSG_` functions were incorrect on illumos. * `SCM_RIGHTS` was also not correct. The correct versions of these functions are in libc, so use them. (I had to bump libc to 0.2.161 to pull in the definition of `POLLRDHUP` on FreeBSD.) This is an intermediate commit that should hopefully be uncontroversial. The full test suite still doesn't pass on illumos yet, but I'm still working on it (in my spare time).
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Hey -- how can I help get this landed? I can revert the glibc change if 2.27 is too new, though note that it covers Ubuntu 18.04, CentOS 8 and Debian buster. |
I've been trying to port ipc-channel to illumos for use in a downstream project, and I found that this code was using a local copy of several functions and constants that are in libc. In particular:
CMSG_functions were incorrect on illumos.SCM_RIGHTSwas also not correct.The correct versions of these functions are in libc, so use them. (I had to bump libc to 0.2.161 to pull in the definition of
POLLRDHUPon FreeBSD.)This is an intermediate commit that should hopefully be uncontroversial. The full test suite still doesn't pass on illumos yet, but I'm still working on it (in my spare time).