126 lines
4.9 KiB
Rust
126 lines
4.9 KiB
Rust
//! Functions which duplicate file descriptors.
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use crate::fd::OwnedFd;
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use crate::{backend, io};
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use backend::fd::AsFd;
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#[cfg(not(target_os = "wasi"))]
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pub use backend::io::types::DupFlags;
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/// `dup(fd)`—Creates a new `OwnedFd` instance that shares the same
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/// underlying [file description] as `fd`.
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///
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/// This function does not set the `O_CLOEXEC` flag. To do a `dup` that does
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/// set `O_CLOEXEC`, use [`fcntl_dupfd_cloexec`].
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///
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/// POSIX guarantees that `dup` will use the lowest unused file descriptor,
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/// however it is not safe in general to rely on this, as file descriptors may
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/// be unexpectedly allocated on other threads or in libraries.
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///
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/// # References
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/// - [POSIX]
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/// - [Linux]
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/// - [Apple]
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/// - [FreeBSD]
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/// - [NetBSD]
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/// - [OpenBSD]
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/// - [DragonFly BSD]
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/// - [illumos]
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/// - [glibc]
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///
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/// [file description]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap03.html#tag_03_258
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/// [`fcntl_dupfd_cloexec`]: crate::io::fcntl_dupfd_cloexec
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/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/dup.html
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/// [Linux]: https://man7.org/linux/man-pages/man2/dup.2.html
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/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/dup.2.html
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/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=dup&sektion=2
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/// [NetBSD]: https://man.netbsd.org/dup.2
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/// [OpenBSD]: https://man.openbsd.org/dup.2
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/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=dup§ion=2
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/// [illumos]: https://illumos.org/man/2/dup
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/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Duplicating-Descriptors.html
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#[cfg(not(target_os = "wasi"))]
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#[inline]
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pub fn dup<Fd: AsFd>(fd: Fd) -> io::Result<OwnedFd> {
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backend::io::syscalls::dup(fd.as_fd())
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}
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/// `dup2(fd, new)`—Changes the [file description] of a file descriptor.
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///
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/// `dup2` conceptually closes `new` and then sets the file description for
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/// `new` to be the same as the one for `fd`. This is a very unusual operation,
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/// and should only be used on file descriptors where you know how `new` will
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/// be subsequently used.
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///
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/// This function does not set the `O_CLOEXEC` flag. To do a `dup2` that does
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/// set `O_CLOEXEC`, use [`dup3`] with [`DupFlags::CLOEXEC`] on platforms which
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/// support it, or [`fcntl_dupfd_cloexec`].
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///
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/// For `dup2` to stdin, stdout, and stderr, see [`stdio::dup2_stdin`],
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/// [`stdio::dup2_stdout`], and [`stdio::dup2_stderr`].
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///
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/// # References
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/// - [POSIX]
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/// - [Linux]
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/// - [Apple]
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/// - [FreeBSD]
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/// - [NetBSD]
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/// - [OpenBSD]
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/// - [DragonFly BSD]
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/// - [illumos]
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/// - [glibc]
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///
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/// [file description]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap03.html#tag_03_258
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/// [`fcntl_dupfd_cloexec`]: crate::io::fcntl_dupfd_cloexec
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/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/dup2.html
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/// [Linux]: https://man7.org/linux/man-pages/man2/dup2.2.html
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/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/dup2.2.html
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/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=dup2&sektion=2
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/// [NetBSD]: https://man.netbsd.org/dup2.2
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/// [OpenBSD]: https://man.openbsd.org/dup2.2
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/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=dup2§ion=2
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/// [illumos]: https://illumos.org/man/2/dup
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/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Duplicating-Descriptors.html
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/// [`stdio::dup2_stdin`]: https://docs.rs/rustix/*/rustix/stdio/fn.dup2_stdin.html
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/// [`stdio::dup2_stdout`]: https://docs.rs/rustix/*/rustix/stdio/fn.dup2_stdout.html
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/// [`stdio::dup2_stderr`]: https://docs.rs/rustix/*/rustix/stdio/fn.dup2_stderr.html
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#[cfg(not(target_os = "wasi"))]
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#[inline]
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pub fn dup2<Fd: AsFd>(fd: Fd, new: &mut OwnedFd) -> io::Result<()> {
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backend::io::syscalls::dup2(fd.as_fd(), new)
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}
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/// `dup3(fd, new, flags)`—Changes the [file description] of a file
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/// descriptor, with flags.
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///
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/// `dup3` is the same as [`dup2`] but adds an additional flags operand, and it
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/// fails in the case that `fd` and `new` have the same file descriptor value.
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/// This additional difference is the reason this function isn't named
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/// `dup2_with`.
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///
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/// # References
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/// - [Linux]
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/// - [FreeBSD]
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/// - [NetBSD]
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/// - [OpenBSD]
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/// - [DragonFly BSD]
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///
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/// [file description]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap03.html#tag_03_258
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/// [Linux]: https://man7.org/linux/man-pages/man2/dup3.2.html
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/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=dup3&sektion=3
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/// [NetBSD]: https://man.netbsd.org/dup3.2
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/// [OpenBSD]: https://man.openbsd.org/dup3.2
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/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=dup3§ion=3
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#[cfg(not(any(
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target_os = "aix",
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target_os = "espidf",
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target_os = "horizon",
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target_os = "nto",
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target_os = "vita",
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target_os = "wasi"
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)))]
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#[inline]
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pub fn dup3<Fd: AsFd>(fd: Fd, new: &mut OwnedFd, flags: DupFlags) -> io::Result<()> {
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backend::io::syscalls::dup3(fd.as_fd(), new, flags)
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}
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