1 use crate::ffi::CString; 2 use crate::path::SMALL_PATH_BUFFER_SIZE; 3 use crate::{backend, io, path}; 4 use alloc::vec::Vec; 5 #[cfg(not(target_os = "fuchsia"))] 6 use backend::fd::AsFd; 7 8 /// `chdir(path)`—Change the current working directory. 9 /// 10 /// # References 11 /// - [POSIX] 12 /// - [Linux] 13 /// 14 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/chdir.html 15 /// [Linux]: https://man7.org/linux/man-pages/man2/chdir.2.html 16 #[inline] chdir<P: path::Arg>(path: P) -> io::Result<()>17pub fn chdir<P: path::Arg>(path: P) -> io::Result<()> { 18 path.into_with_c_str(backend::process::syscalls::chdir) 19 } 20 21 /// `fchdir(fd)`—Change the current working directory. 22 /// 23 /// # References 24 /// - [POSIX] 25 /// - [Linux] 26 /// 27 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/fchdir.html 28 /// [Linux]: https://man7.org/linux/man-pages/man2/fchdir.2.html 29 #[cfg(not(target_os = "fuchsia"))] 30 #[inline] fchdir<Fd: AsFd>(fd: Fd) -> io::Result<()>31pub fn fchdir<Fd: AsFd>(fd: Fd) -> io::Result<()> { 32 backend::process::syscalls::fchdir(fd.as_fd()) 33 } 34 35 /// `getcwd()`—Return the current working directory. 36 /// 37 /// If `reuse` is non-empty, reuse its buffer to store the result if possible. 38 /// 39 /// # References 40 /// - [POSIX] 41 /// - [Linux] 42 /// 43 /// [POSIX]: https://pubs.opengroup.org/onlinepubs/9699919799/functions/getcwd.html 44 /// [Linux]: https://man7.org/linux/man-pages/man3/getcwd.3.html 45 #[cfg(not(target_os = "wasi"))] 46 #[inline] getcwd<B: Into<Vec<u8>>>(reuse: B) -> io::Result<CString>47pub fn getcwd<B: Into<Vec<u8>>>(reuse: B) -> io::Result<CString> { 48 _getcwd(reuse.into()) 49 } 50 _getcwd(mut buffer: Vec<u8>) -> io::Result<CString>51fn _getcwd(mut buffer: Vec<u8>) -> io::Result<CString> { 52 // This code would benefit from having a better way to read into 53 // uninitialized memory, but that requires `unsafe`. 54 buffer.clear(); 55 buffer.reserve(SMALL_PATH_BUFFER_SIZE); 56 buffer.resize(buffer.capacity(), 0_u8); 57 58 loop { 59 match backend::process::syscalls::getcwd(&mut buffer) { 60 Err(io::Errno::RANGE) => { 61 buffer.reserve(1); // use `Vec` reallocation strategy to grow capacity exponentially 62 buffer.resize(buffer.capacity(), 0_u8); 63 } 64 Ok(_) => { 65 let len = buffer.iter().position(|x| *x == b'\0').unwrap(); 66 buffer.resize(len, 0_u8); 67 return Ok(CString::new(buffer).unwrap()); 68 } 69 Err(errno) => return Err(errno), 70 } 71 } 72 } 73