Crate palaver[−][src]

Cross-platform polyfills.

This library attempts to provide reliable pollyfills for functionality that isn't implemented on all platforms, for example gettid, memfd_create, fexecve, as well as providing non-atomic versions of functions like accept4, socket+SOCK_CLOEXEC, pipe2, and other miscellanea like seal to make a file descriptor read-only thus suitable for fexecve.

palaver = "Platform Abstraction Layer" / pa·lav·er n. – prolonged and tedious fuss.

It's currently used on unix-family systems; most Windows functionality is TODO.

Structs

SockFlag

Akin to nix::sys::socket::SockFlag but avail cross-platform

Functions

accept	Like accept4, falls back to non-atomic accept
copy	Loops io::copy till len elapsed or error
copy_sendfile	Loops sendfile till len elapsed or error
copy_splice	Loops splice till len elapsed or error
dup	Like dup except O_CLOEXEC can be passed atomically
dup_to	Like dup2/3; automatically retries on EBUSY on Linux
fexecve	Falls back to execve("/proc/self/fd/{fd}",...), falls back to execve("/tmp/{randomfilename}")
gettid	Get an identifier for the thread; uses gettid on linux; pthread_threadid_np on mac; GetCurrentThreadId on windows.
is_connected	Intended to check for completion after `connect(2)` has returned `EINPROGRESS`.
is_valgrind	Check if we're running under valgrind
memfd_create	Falls back to shm_open, falls back to creating+unlinking /tmp/{random_filename}
move_fds	Maps file descriptors [(from,to)]
pipe	Like pipe2; not atomic on platforms that lack it
seal	Makes a file descriptor read-only, which seems neccessary on some platforms to pass to fexecve and is good practise anyway
socket	Falls back to non-atomic if SOCK_NONBLOCK/SOCK_CLOEXEC unavailable
spawn	A wrapper around `std::thread::spawn()` that blocks until the new thread has left library code. Library code can do things like temporarily opening fds (leading to dup2 on other threads returning EBUSY on Linux), so blocking this thread until it's done just makes things more predictable.
unreceived	Count of bytes that have yet to be read from a socket
unsent	Count of bytes that have been written to a socket, but have yet to be acked by the remote end
valgrind_start_fd	Valgrind sets up various file descriptors for its purposes; they're all > any user fds, and this function gets the lowest of them