| //! Functions which operate on file descriptors which might be terminals. |
| |
| use crate::backend; |
| use backend::fd::AsFd; |
| #[cfg(all(feature = "alloc", feature = "procfs"))] |
| #[cfg(not(any(target_os = "fuchsia", target_os = "wasi")))] |
| use { |
| crate::ffi::CString, crate::io, crate::path::SMALL_PATH_BUFFER_SIZE, alloc::vec::Vec, |
| backend::fd::BorrowedFd, |
| }; |
| |
| /// `isatty(fd)`—Tests whether a file descriptor refers to a terminal. |
| /// |
| /// # References |
| /// - [POSIX] |
| /// - [Linux] |
| /// |
| /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/isatty.html |
| /// [Linux]: https://man7.org/linux/man-pages/man3/isatty.3.html |
| #[inline] |
| pub fn isatty<Fd: AsFd>(fd: Fd) -> bool { |
| backend::termios::syscalls::isatty(fd.as_fd()) |
| } |
| |
| /// `ttyname_r(fd)` |
| /// |
| /// If `reuse` already has available capacity, reuse it if possible. |
| /// |
| /// # References |
| /// - [POSIX] |
| /// - [Linux] |
| /// |
| /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/ttyname.html |
| /// [Linux]: https://man7.org/linux/man-pages/man3/ttyname.3.html |
| #[cfg(not(any(target_os = "fuchsia", target_os = "wasi")))] |
| #[cfg(all(feature = "alloc", feature = "procfs"))] |
| #[cfg_attr(doc_cfg, doc(cfg(feature = "procfs")))] |
| #[doc(alias = "ttyname_r")] |
| #[inline] |
| pub fn ttyname<Fd: AsFd, B: Into<Vec<u8>>>(dirfd: Fd, reuse: B) -> io::Result<CString> { |
| _ttyname(dirfd.as_fd(), reuse.into()) |
| } |
| |
| #[cfg(not(any(target_os = "fuchsia", target_os = "wasi")))] |
| #[cfg(all(feature = "alloc", feature = "procfs"))] |
| #[allow(unsafe_code)] |
| fn _ttyname(dirfd: BorrowedFd<'_>, mut buffer: Vec<u8>) -> io::Result<CString> { |
| buffer.clear(); |
| buffer.reserve(SMALL_PATH_BUFFER_SIZE); |
| |
| loop { |
| match backend::termios::syscalls::ttyname(dirfd, buffer.spare_capacity_mut()) { |
| Err(io::Errno::RANGE) => { |
| // Use `Vec` reallocation strategy to grow capacity |
| // exponentially. |
| buffer.reserve(buffer.capacity() + 1); |
| } |
| Ok(len) => { |
| // SAFETY: Assume the backend returns the length of the string |
| // excluding the NUL. |
| unsafe { |
| buffer.set_len(len + 1); |
| } |
| |
| // SAFETY: |
| // - “ttyname_r stores this pathname in the buffer buf” |
| // - [POSIX definition 3.271: Pathname]: “A string that is used |
| // to identify a file.” |
| // - [POSIX definition 3.375: String]: “A contiguous sequence |
| // of bytes terminated by and including the first null byte.” |
| // |
| // Thus, there will be a single NUL byte at the end of the |
| // string. |
| // |
| // [POSIX definition 3.271: Pathname]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_271 |
| // [POSIX definition 3.375: String]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_375 |
| unsafe { |
| return Ok(CString::from_vec_with_nul_unchecked(buffer)); |
| } |
| } |
| Err(errno) => return Err(errno), |
| } |
| } |
| } |