From dc0db358abe19481e475e10c32149b53370f1a1c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Thu, 30 May 2024 05:57:31 +0200 Subject: Merging upstream version 1.72.1+dfsg1. Signed-off-by: Daniel Baumann --- vendor/rustix/src/process/chdir.rs | 52 ++++++++++++++++++++++++++------------ 1 file changed, 36 insertions(+), 16 deletions(-) (limited to 'vendor/rustix/src/process/chdir.rs') diff --git a/vendor/rustix/src/process/chdir.rs b/vendor/rustix/src/process/chdir.rs index 4951e5670..0da0b5c2e 100644 --- a/vendor/rustix/src/process/chdir.rs +++ b/vendor/rustix/src/process/chdir.rs @@ -1,9 +1,13 @@ -use crate::ffi::CString; -use crate::path::SMALL_PATH_BUFFER_SIZE; -use crate::{backend, io, path}; -use alloc::vec::Vec; #[cfg(not(target_os = "fuchsia"))] -use backend::fd::AsFd; +use crate::backend::fd::AsFd; +#[cfg(any(feature = "fs", not(target_os = "fuchsia")))] +use crate::{backend, io}; +#[cfg(feature = "fs")] +use { + crate::ffi::{CStr, CString}, + crate::path::{self, SMALL_PATH_BUFFER_SIZE}, + alloc::vec::Vec, +}; /// `chdir(path)`—Change the current working directory. /// @@ -14,6 +18,8 @@ use backend::fd::AsFd; /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/chdir.html /// [Linux]: https://man7.org/linux/man-pages/man2/chdir.2.html #[inline] +#[cfg(feature = "fs")] +#[cfg_attr(doc_cfg, doc(cfg(feature = "fs")))] pub fn chdir(path: P) -> io::Result<()> { path.into_with_c_str(backend::process::syscalls::chdir) } @@ -32,9 +38,9 @@ pub fn fchdir(fd: Fd) -> io::Result<()> { backend::process::syscalls::fchdir(fd.as_fd()) } -/// `getcwd()`—Return the current working directory. +/// `getCWD`—Return the current working directory. /// -/// If `reuse` is non-empty, reuse its buffer to store the result if possible. +/// If `reuse` already has available capacity, reuse it if possible. /// /// # References /// - [POSIX] @@ -42,29 +48,43 @@ pub fn fchdir(fd: Fd) -> io::Result<()> { /// /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/getcwd.html /// [Linux]: https://man7.org/linux/man-pages/man3/getcwd.3.html +#[cfg(feature = "fs")] #[cfg(not(target_os = "wasi"))] +#[cfg_attr(doc_cfg, doc(cfg(feature = "fs")))] #[inline] pub fn getcwd>>(reuse: B) -> io::Result { _getcwd(reuse.into()) } +#[cfg(feature = "fs")] +#[allow(unsafe_code)] fn _getcwd(mut buffer: Vec) -> io::Result { - // This code would benefit from having a better way to read into - // uninitialized memory, but that requires `unsafe`. buffer.clear(); buffer.reserve(SMALL_PATH_BUFFER_SIZE); - buffer.resize(buffer.capacity(), 0_u8); loop { - match backend::process::syscalls::getcwd(&mut buffer) { + match backend::process::syscalls::getcwd(buffer.spare_capacity_mut()) { Err(io::Errno::RANGE) => { - buffer.reserve(1); // use `Vec` reallocation strategy to grow capacity exponentially - buffer.resize(buffer.capacity(), 0_u8); + buffer.reserve(buffer.capacity() + 1); // use `Vec` reallocation strategy to grow capacity exponentially } Ok(_) => { - let len = buffer.iter().position(|x| *x == b'\0').unwrap(); - buffer.resize(len, 0_u8); - return Ok(CString::new(buffer).unwrap()); + // SAFETY: + // - "These functions return a null-terminated string" + // - [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 3.375: String]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_375 + unsafe { + buffer.set_len( + CStr::from_ptr(buffer.as_ptr().cast()) + .to_bytes_with_nul() + .len(), + ); + + return Ok(CString::from_vec_with_nul_unchecked(buffer)); + } } Err(errno) => return Err(errno), } -- cgit v1.2.3