1//! The Unix `fcntl` function is effectively lots of different functions hidden
2//! behind a single dynamic dispatch interface. In order to provide a type-safe
3//! API, rustix makes them all separate functions so that they can have
4//! dedicated static type signatures.
5//!
6//! `fcntl` functions which are not specific to files or directories live in
7//! the [`io`] module instead.
8//!
9//! [`io`]: crate::io
10
11use crate::{backend, io};
12use backend::fd::{AsFd, OwnedFd, RawFd};
13
14pub use backend::io::types::FdFlags;
15
16/// `fcntl(fd, F_GETFD)`—Returns a file descriptor's flags.
17///
18/// # References
19/// - [POSIX]
20/// - [Linux]
21/// - [Apple]
22/// - [FreeBSD]
23/// - [NetBSD]
24/// - [OpenBSD]
25/// - [DragonFly BSD]
26/// - [illumos]
27/// - [glibc]
28///
29/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html
30/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html
31/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/fcntl.2.html
32/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=fcntl&sektion=2
33/// [NetBSD]: https://man.netbsd.org/fcntl.2
34/// [OpenBSD]: https://man.openbsd.org/fcntl.2
35/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=fcntl&section=2
36/// [illumos]: https://illumos.org/man/2/fcntl
37/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Control-Operations.html#index-fcntl-function
38#[inline]
39#[doc(alias = "F_GETFD")]
40pub fn fcntl_getfd<Fd: AsFd>(fd: Fd) -> io::Result<FdFlags> {
41 backend::io::syscalls::fcntl_getfd(fd.as_fd())
42}
43
44/// `fcntl(fd, F_SETFD, flags)`—Sets a file descriptor's flags.
45///
46/// # References
47/// - [POSIX]
48/// - [Linux]
49/// - [Apple]
50/// - [FreeBSD]
51/// - [NetBSD]
52/// - [OpenBSD]
53/// - [DragonFly BSD]
54/// - [illumos]
55/// - [glibc]
56///
57/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html
58/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html
59/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/fcntl.2.html
60/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=fcntl&sektion=2
61/// [NetBSD]: https://man.netbsd.org/fcntl.2
62/// [OpenBSD]: https://man.openbsd.org/fcntl.2
63/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=fcntl&section=2
64/// [illumos]: https://illumos.org/man/2/fcntl
65/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Control-Operations.html#index-fcntl-function
66#[inline]
67#[doc(alias = "F_SETFD")]
68pub fn fcntl_setfd<Fd: AsFd>(fd: Fd, flags: FdFlags) -> io::Result<()> {
69 backend::io::syscalls::fcntl_setfd(fd.as_fd(), flags)
70}
71
72/// `fcntl(fd, F_DUPFD_CLOEXEC)`—Creates a new `OwnedFd` instance, with value
73/// at least `min`, that has `O_CLOEXEC` set and that shares the same
74/// underlying [file description] as `fd`.
75///
76/// POSIX guarantees that `F_DUPFD_CLOEXEC` will use the lowest unused file
77/// descriptor which is at least `min`, however it is not safe in general to
78/// rely on this, as file descriptors may be unexpectedly allocated on other
79/// threads or in libraries.
80///
81/// # References
82/// - [POSIX]
83/// - [Linux]
84/// - [Apple]
85/// - [FreeBSD]
86/// - [NetBSD]
87/// - [OpenBSD]
88/// - [DragonFly BSD]
89/// - [illumos]
90/// - [glibc]
91///
92/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html
93/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html
94/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/fcntl.2.html
95/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=fcntl&sektion=2
96/// [NetBSD]: https://man.netbsd.org/fcntl.2
97/// [OpenBSD]: https://man.openbsd.org/fcntl.2
98/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=fcntl&section=2
99/// [illumos]: https://illumos.org/man/2/fcntl
100/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Control-Operations.html#index-fcntl-function
101/// [file description]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap03.html#tag_03_258
102#[cfg(not(any(target_os = "espidf", target_os = "wasi")))]
103#[inline]
104#[doc(alias = "F_DUPFD_CLOEXEC")]
105pub fn fcntl_dupfd_cloexec<Fd: AsFd>(fd: Fd, min: RawFd) -> io::Result<OwnedFd> {
106 backend::io::syscalls::fcntl_dupfd_cloexec(fd.as_fd(), min)
107}
108
109/// `fcntl(fd, F_DUPFD)`—Creates a new `OwnedFd` instance, with value at
110/// least `min`, that shares the same underlying [file description] as `fd`.
111///
112/// POSIX guarantees that `F_DUPFD` will use the lowest unused file descriptor
113/// which is at least `min`, however it is not safe in general to rely on this,
114/// as file descriptors may be unexpectedly allocated on other threads or in
115/// libraries.
116///
117/// # References
118/// - [POSIX]
119/// - [Linux]
120/// - [Apple]
121/// - [FreeBSD]
122/// - [NetBSD]
123/// - [OpenBSD]
124/// - [DragonFly BSD]
125/// - [illumos]
126/// - [glibc]
127///
128/// [POSIX]: https://pubs.opengroup.org/onlinepubs/9799919799/functions/fcntl.html
129/// [Linux]: https://man7.org/linux/man-pages/man2/fcntl.2.html
130/// [Apple]: https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/fcntl.2.html
131/// [FreeBSD]: https://man.freebsd.org/cgi/man.cgi?query=fcntl&sektion=2
132/// [NetBSD]: https://man.netbsd.org/fcntl.2
133/// [OpenBSD]: https://man.openbsd.org/fcntl.2
134/// [DragonFly BSD]: https://man.dragonflybsd.org/?command=fcntl&section=2
135/// [illumos]: https://illumos.org/man/2/fcntl
136/// [glibc]: https://sourceware.org/glibc/manual/latest/html_node/Control-Operations.html#index-fcntl-function
137/// [file description]: https://pubs.opengroup.org/onlinepubs/9799919799/basedefs/V1_chap03.html#tag_03_258
138#[cfg(target_os = "espidf")]
139#[inline]
140#[doc(alias = "F_DUPFD")]
141pub fn fcntl_dupfd<Fd: AsFd>(fd: Fd, min: RawFd) -> io::Result<OwnedFd> {
142 backend::io::syscalls::fcntl_dupfd(fd.as_fd(), min)
143}
144