diff options
Diffstat (limited to 'library/std/src/env.rs')
| -rw-r--r-- | library/std/src/env.rs | 982 |
1 files changed, 982 insertions, 0 deletions
diff --git a/library/std/src/env.rs b/library/std/src/env.rs new file mode 100644 index 000000000..463f71406 --- /dev/null +++ b/library/std/src/env.rs @@ -0,0 +1,982 @@ +//! Inspection and manipulation of the process's environment. +//! +//! This module contains functions to inspect various aspects such as +//! environment variables, process arguments, the current directory, and various +//! other important directories. +//! +//! There are several functions and structs in this module that have a +//! counterpart ending in `os`. Those ending in `os` will return an [`OsString`] +//! and those without will return a [`String`]. + +#![stable(feature = "env", since = "1.0.0")] + +#[cfg(test)] +mod tests; + +use crate::error::Error; +use crate::ffi::{OsStr, OsString}; +use crate::fmt; +use crate::io; +use crate::path::{Path, PathBuf}; +use crate::sys; +use crate::sys::os as os_imp; + +/// Returns the current working directory as a [`PathBuf`]. +/// +/// # Platform-specific behavior +/// +/// This function [currently] corresponds to the `getcwd` function on Unix +/// and the `GetCurrentDirectoryW` function on Windows. +/// +/// [currently]: crate::io#platform-specific-behavior +/// +/// # Errors +/// +/// Returns an [`Err`] if the current working directory value is invalid. +/// Possible cases: +/// +/// * Current directory does not exist. +/// * There are insufficient permissions to access the current directory. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// fn main() -> std::io::Result<()> { +/// let path = env::current_dir()?; +/// println!("The current directory is {}", path.display()); +/// Ok(()) +/// } +/// ``` +#[doc(alias = "pwd")] +#[doc(alias = "getcwd")] +#[doc(alias = "GetCurrentDirectory")] +#[stable(feature = "env", since = "1.0.0")] +pub fn current_dir() -> io::Result<PathBuf> { + os_imp::getcwd() +} + +/// Changes the current working directory to the specified path. +/// +/// # Platform-specific behavior +/// +/// This function [currently] corresponds to the `chdir` function on Unix +/// and the `SetCurrentDirectoryW` function on Windows. +/// +/// Returns an [`Err`] if the operation fails. +/// +/// [currently]: crate::io#platform-specific-behavior +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// use std::path::Path; +/// +/// let root = Path::new("/"); +/// assert!(env::set_current_dir(&root).is_ok()); +/// println!("Successfully changed working directory to {}!", root.display()); +/// ``` +#[doc(alias = "chdir")] +#[stable(feature = "env", since = "1.0.0")] +pub fn set_current_dir<P: AsRef<Path>>(path: P) -> io::Result<()> { + os_imp::chdir(path.as_ref()) +} + +/// An iterator over a snapshot of the environment variables of this process. +/// +/// This structure is created by [`env::vars()`]. See its documentation for more. +/// +/// [`env::vars()`]: vars +#[stable(feature = "env", since = "1.0.0")] +pub struct Vars { + inner: VarsOs, +} + +/// An iterator over a snapshot of the environment variables of this process. +/// +/// This structure is created by [`env::vars_os()`]. See its documentation for more. +/// +/// [`env::vars_os()`]: vars_os +#[stable(feature = "env", since = "1.0.0")] +pub struct VarsOs { + inner: os_imp::Env, +} + +/// Returns an iterator of (variable, value) pairs of strings, for all the +/// environment variables of the current process. +/// +/// The returned iterator contains a snapshot of the process's environment +/// variables at the time of this invocation. Modifications to environment +/// variables afterwards will not be reflected in the returned iterator. +/// +/// # Panics +/// +/// While iterating, the returned iterator will panic if any key or value in the +/// environment is not valid unicode. If this is not desired, consider using +/// [`env::vars_os()`]. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// // We will iterate through the references to the element returned by +/// // env::vars(); +/// for (key, value) in env::vars() { +/// println!("{key}: {value}"); +/// } +/// ``` +/// +/// [`env::vars_os()`]: vars_os +#[must_use] +#[stable(feature = "env", since = "1.0.0")] +pub fn vars() -> Vars { + Vars { inner: vars_os() } +} + +/// Returns an iterator of (variable, value) pairs of OS strings, for all the +/// environment variables of the current process. +/// +/// The returned iterator contains a snapshot of the process's environment +/// variables at the time of this invocation. Modifications to environment +/// variables afterwards will not be reflected in the returned iterator. +/// +/// Note that the returned iterator will not check if the environment variables +/// are valid Unicode. If you want to panic on invalid UTF-8, +/// use the [`vars`] function instead. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// // We will iterate through the references to the element returned by +/// // env::vars_os(); +/// for (key, value) in env::vars_os() { +/// println!("{key:?}: {value:?}"); +/// } +/// ``` +#[must_use] +#[stable(feature = "env", since = "1.0.0")] +pub fn vars_os() -> VarsOs { + VarsOs { inner: os_imp::env() } +} + +#[stable(feature = "env", since = "1.0.0")] +impl Iterator for Vars { + type Item = (String, String); + fn next(&mut self) -> Option<(String, String)> { + self.inner.next().map(|(a, b)| (a.into_string().unwrap(), b.into_string().unwrap())) + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.inner.size_hint() + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for Vars { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Vars").finish_non_exhaustive() + } +} + +#[stable(feature = "env", since = "1.0.0")] +impl Iterator for VarsOs { + type Item = (OsString, OsString); + fn next(&mut self) -> Option<(OsString, OsString)> { + self.inner.next() + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.inner.size_hint() + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for VarsOs { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("VarOs").finish_non_exhaustive() + } +} + +/// Fetches the environment variable `key` from the current process. +/// +/// # Errors +/// +/// This function will return an error if the environment variable isn't set. +/// +/// This function may return an error if the environment variable's name contains +/// the equal sign character (`=`) or the NUL character. +/// +/// This function will return an error if the environment variable's value is +/// not valid Unicode. If this is not desired, consider using [`var_os`]. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// let key = "HOME"; +/// match env::var(key) { +/// Ok(val) => println!("{key}: {val:?}"), +/// Err(e) => println!("couldn't interpret {key}: {e}"), +/// } +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn var<K: AsRef<OsStr>>(key: K) -> Result<String, VarError> { + _var(key.as_ref()) +} + +fn _var(key: &OsStr) -> Result<String, VarError> { + match var_os(key) { + Some(s) => s.into_string().map_err(VarError::NotUnicode), + None => Err(VarError::NotPresent), + } +} + +/// Fetches the environment variable `key` from the current process, returning +/// [`None`] if the variable isn't set or there's another error. +/// +/// Note that the method will not check if the environment variable +/// is valid Unicode. If you want to have an error on invalid UTF-8, +/// use the [`var`] function instead. +/// +/// # Errors +/// +/// This function returns an error if the environment variable isn't set. +/// +/// This function may return an error if the environment variable's name contains +/// the equal sign character (`=`) or the NUL character. +/// +/// This function may return an error if the environment variable's value contains +/// the NUL character. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// let key = "HOME"; +/// match env::var_os(key) { +/// Some(val) => println!("{key}: {val:?}"), +/// None => println!("{key} is not defined in the environment.") +/// } +/// ``` +#[must_use] +#[stable(feature = "env", since = "1.0.0")] +pub fn var_os<K: AsRef<OsStr>>(key: K) -> Option<OsString> { + _var_os(key.as_ref()) +} + +fn _var_os(key: &OsStr) -> Option<OsString> { + os_imp::getenv(key) +} + +/// The error type for operations interacting with environment variables. +/// Possibly returned from [`env::var()`]. +/// +/// [`env::var()`]: var +#[derive(Debug, PartialEq, Eq, Clone)] +#[stable(feature = "env", since = "1.0.0")] +pub enum VarError { + /// The specified environment variable was not present in the current + /// process's environment. + #[stable(feature = "env", since = "1.0.0")] + NotPresent, + + /// The specified environment variable was found, but it did not contain + /// valid unicode data. The found data is returned as a payload of this + /// variant. + #[stable(feature = "env", since = "1.0.0")] + NotUnicode(#[stable(feature = "env", since = "1.0.0")] OsString), +} + +#[stable(feature = "env", since = "1.0.0")] +impl fmt::Display for VarError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + match *self { + VarError::NotPresent => write!(f, "environment variable not found"), + VarError::NotUnicode(ref s) => { + write!(f, "environment variable was not valid unicode: {:?}", s) + } + } + } +} + +#[stable(feature = "env", since = "1.0.0")] +impl Error for VarError { + #[allow(deprecated)] + fn description(&self) -> &str { + match *self { + VarError::NotPresent => "environment variable not found", + VarError::NotUnicode(..) => "environment variable was not valid unicode", + } + } +} + +/// Sets the environment variable `key` to the value `value` for the currently running +/// process. +/// +/// Note that while concurrent access to environment variables is safe in Rust, +/// some platforms only expose inherently unsafe non-threadsafe APIs for +/// inspecting the environment. As a result, extra care needs to be taken when +/// auditing calls to unsafe external FFI functions to ensure that any external +/// environment accesses are properly synchronized with accesses in Rust. +/// +/// Discussion of this unsafety on Unix may be found in: +/// +/// - [Austin Group Bugzilla](https://austingroupbugs.net/view.php?id=188) +/// - [GNU C library Bugzilla](https://sourceware.org/bugzilla/show_bug.cgi?id=15607#c2) +/// +/// # Panics +/// +/// This function may panic if `key` is empty, contains an ASCII equals sign `'='` +/// or the NUL character `'\0'`, or when `value` contains the NUL character. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// let key = "KEY"; +/// env::set_var(key, "VALUE"); +/// assert_eq!(env::var(key), Ok("VALUE".to_string())); +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn set_var<K: AsRef<OsStr>, V: AsRef<OsStr>>(key: K, value: V) { + _set_var(key.as_ref(), value.as_ref()) +} + +fn _set_var(key: &OsStr, value: &OsStr) { + os_imp::setenv(key, value).unwrap_or_else(|e| { + panic!("failed to set environment variable `{key:?}` to `{value:?}`: {e}") + }) +} + +/// Removes an environment variable from the environment of the currently running process. +/// +/// Note that while concurrent access to environment variables is safe in Rust, +/// some platforms only expose inherently unsafe non-threadsafe APIs for +/// inspecting the environment. As a result extra care needs to be taken when +/// auditing calls to unsafe external FFI functions to ensure that any external +/// environment accesses are properly synchronized with accesses in Rust. +/// +/// Discussion of this unsafety on Unix may be found in: +/// +/// - [Austin Group Bugzilla](https://austingroupbugs.net/view.php?id=188) +/// - [GNU C library Bugzilla](https://sourceware.org/bugzilla/show_bug.cgi?id=15607#c2) +/// +/// # Panics +/// +/// This function may panic if `key` is empty, contains an ASCII equals sign +/// `'='` or the NUL character `'\0'`, or when the value contains the NUL +/// character. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// let key = "KEY"; +/// env::set_var(key, "VALUE"); +/// assert_eq!(env::var(key), Ok("VALUE".to_string())); +/// +/// env::remove_var(key); +/// assert!(env::var(key).is_err()); +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn remove_var<K: AsRef<OsStr>>(key: K) { + _remove_var(key.as_ref()) +} + +fn _remove_var(key: &OsStr) { + os_imp::unsetenv(key) + .unwrap_or_else(|e| panic!("failed to remove environment variable `{key:?}`: {e}")) +} + +/// An iterator that splits an environment variable into paths according to +/// platform-specific conventions. +/// +/// The iterator element type is [`PathBuf`]. +/// +/// This structure is created by [`env::split_paths()`]. See its +/// documentation for more. +/// +/// [`env::split_paths()`]: split_paths +#[must_use = "iterators are lazy and do nothing unless consumed"] +#[stable(feature = "env", since = "1.0.0")] +pub struct SplitPaths<'a> { + inner: os_imp::SplitPaths<'a>, +} + +/// Parses input according to platform conventions for the `PATH` +/// environment variable. +/// +/// Returns an iterator over the paths contained in `unparsed`. The iterator +/// element type is [`PathBuf`]. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// let key = "PATH"; +/// match env::var_os(key) { +/// Some(paths) => { +/// for path in env::split_paths(&paths) { +/// println!("'{}'", path.display()); +/// } +/// } +/// None => println!("{key} is not defined in the environment.") +/// } +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn split_paths<T: AsRef<OsStr> + ?Sized>(unparsed: &T) -> SplitPaths<'_> { + SplitPaths { inner: os_imp::split_paths(unparsed.as_ref()) } +} + +#[stable(feature = "env", since = "1.0.0")] +impl<'a> Iterator for SplitPaths<'a> { + type Item = PathBuf; + fn next(&mut self) -> Option<PathBuf> { + self.inner.next() + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.inner.size_hint() + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for SplitPaths<'_> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("SplitPaths").finish_non_exhaustive() + } +} + +/// The error type for operations on the `PATH` variable. Possibly returned from +/// [`env::join_paths()`]. +/// +/// [`env::join_paths()`]: join_paths +#[derive(Debug)] +#[stable(feature = "env", since = "1.0.0")] +pub struct JoinPathsError { + inner: os_imp::JoinPathsError, +} + +/// Joins a collection of [`Path`]s appropriately for the `PATH` +/// environment variable. +/// +/// # Errors +/// +/// Returns an [`Err`] (containing an error message) if one of the input +/// [`Path`]s contains an invalid character for constructing the `PATH` +/// variable (a double quote on Windows or a colon on Unix). +/// +/// # Examples +/// +/// Joining paths on a Unix-like platform: +/// +/// ``` +/// use std::env; +/// use std::ffi::OsString; +/// use std::path::Path; +/// +/// fn main() -> Result<(), env::JoinPathsError> { +/// # if cfg!(unix) { +/// let paths = [Path::new("/bin"), Path::new("/usr/bin")]; +/// let path_os_string = env::join_paths(paths.iter())?; +/// assert_eq!(path_os_string, OsString::from("/bin:/usr/bin")); +/// # } +/// Ok(()) +/// } +/// ``` +/// +/// Joining a path containing a colon on a Unix-like platform results in an +/// error: +/// +/// ``` +/// # if cfg!(unix) { +/// use std::env; +/// use std::path::Path; +/// +/// let paths = [Path::new("/bin"), Path::new("/usr/bi:n")]; +/// assert!(env::join_paths(paths.iter()).is_err()); +/// # } +/// ``` +/// +/// Using `env::join_paths()` with [`env::split_paths()`] to append an item to +/// the `PATH` environment variable: +/// +/// ``` +/// use std::env; +/// use std::path::PathBuf; +/// +/// fn main() -> Result<(), env::JoinPathsError> { +/// if let Some(path) = env::var_os("PATH") { +/// let mut paths = env::split_paths(&path).collect::<Vec<_>>(); +/// paths.push(PathBuf::from("/home/xyz/bin")); +/// let new_path = env::join_paths(paths)?; +/// env::set_var("PATH", &new_path); +/// } +/// +/// Ok(()) +/// } +/// ``` +/// +/// [`env::split_paths()`]: split_paths +#[stable(feature = "env", since = "1.0.0")] +pub fn join_paths<I, T>(paths: I) -> Result<OsString, JoinPathsError> +where + I: IntoIterator<Item = T>, + T: AsRef<OsStr>, +{ + os_imp::join_paths(paths.into_iter()).map_err(|e| JoinPathsError { inner: e }) +} + +#[stable(feature = "env", since = "1.0.0")] +impl fmt::Display for JoinPathsError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.inner.fmt(f) + } +} + +#[stable(feature = "env", since = "1.0.0")] +impl Error for JoinPathsError { + #[allow(deprecated, deprecated_in_future)] + fn description(&self) -> &str { + self.inner.description() + } +} + +/// Returns the path of the current user's home directory if known. +/// +/// # Unix +/// +/// - Returns the value of the 'HOME' environment variable if it is set +/// (including to an empty string). +/// - Otherwise, it tries to determine the home directory by invoking the `getpwuid_r` function +/// using the UID of the current user. An empty home directory field returned from the +/// `getpwuid_r` function is considered to be a valid value. +/// - Returns `None` if the current user has no entry in the /etc/passwd file. +/// +/// # Windows +/// +/// - Returns the value of the 'HOME' environment variable if it is set +/// (including to an empty string). +/// - Otherwise, returns the value of the 'USERPROFILE' environment variable if it is set +/// (including to an empty string). +/// - If both do not exist, [`GetUserProfileDirectory`][msdn] is used to return the path. +/// +/// [msdn]: https://docs.microsoft.com/en-us/windows/win32/api/userenv/nf-userenv-getuserprofiledirectorya +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// match env::home_dir() { +/// Some(path) => println!("Your home directory, probably: {}", path.display()), +/// None => println!("Impossible to get your home dir!"), +/// } +/// ``` +#[deprecated( + since = "1.29.0", + note = "This function's behavior is unexpected and probably not what you want. \ + Consider using a crate from crates.io instead." +)] +#[must_use] +#[stable(feature = "env", since = "1.0.0")] +pub fn home_dir() -> Option<PathBuf> { + os_imp::home_dir() +} + +/// Returns the path of a temporary directory. +/// +/// The temporary directory may be shared among users, or between processes +/// with different privileges; thus, the creation of any files or directories +/// in the temporary directory must use a secure method to create a uniquely +/// named file. Creating a file or directory with a fixed or predictable name +/// may result in "insecure temporary file" security vulnerabilities. Consider +/// using a crate that securely creates temporary files or directories. +/// +/// # Platform-specific behavior +/// +/// On Unix, returns the value of the `TMPDIR` environment variable if it is +/// set, otherwise for non-Android it returns `/tmp`. If Android, since there +/// is no global temporary folder (it is usually allocated per-app), it returns +/// `/data/local/tmp`. +/// On Windows, the behavior is equivalent to that of [`GetTempPath2`][GetTempPath2] / +/// [`GetTempPath`][GetTempPath], which this function uses internally. +/// Note that, this [may change in the future][changes]. +/// +/// [changes]: io#platform-specific-behavior +/// [GetTempPath2]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettemppath2a +/// [GetTempPath]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-gettemppatha +/// +/// ```no_run +/// use std::env; +/// +/// fn main() { +/// let dir = env::temp_dir(); +/// println!("Temporary directory: {}", dir.display()); +/// } +/// ``` +#[must_use] +#[stable(feature = "env", since = "1.0.0")] +pub fn temp_dir() -> PathBuf { + os_imp::temp_dir() +} + +/// Returns the full filesystem path of the current running executable. +/// +/// # Platform-specific behavior +/// +/// If the executable was invoked through a symbolic link, some platforms will +/// return the path of the symbolic link and other platforms will return the +/// path of the symbolic link’s target. +/// +/// If the executable is renamed while it is running, platforms may return the +/// path at the time it was loaded instead of the new path. +/// +/// # Errors +/// +/// Acquiring the path of the current executable is a platform-specific operation +/// that can fail for a good number of reasons. Some errors can include, but not +/// be limited to, filesystem operations failing or general syscall failures. +/// +/// # Security +/// +/// The output of this function should not be trusted for anything +/// that might have security implications. Basically, if users can run +/// the executable, they can change the output arbitrarily. +/// +/// As an example, you can easily introduce a race condition. It goes +/// like this: +/// +/// 1. You get the path to the current executable using `current_exe()`, and +/// store it in a variable. +/// 2. Time passes. A malicious actor removes the current executable, and +/// replaces it with a malicious one. +/// 3. You then use the stored path to re-execute the current +/// executable. +/// +/// You expected to safely execute the current executable, but you're +/// instead executing something completely different. The code you +/// just executed run with your privileges. +/// +/// This sort of behavior has been known to [lead to privilege escalation] when +/// used incorrectly. +/// +/// [lead to privilege escalation]: https://securityvulns.com/Wdocument183.html +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// match env::current_exe() { +/// Ok(exe_path) => println!("Path of this executable is: {}", +/// exe_path.display()), +/// Err(e) => println!("failed to get current exe path: {e}"), +/// }; +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn current_exe() -> io::Result<PathBuf> { + os_imp::current_exe() +} + +/// An iterator over the arguments of a process, yielding a [`String`] value for +/// each argument. +/// +/// This struct is created by [`env::args()`]. See its documentation +/// for more. +/// +/// The first element is traditionally the path of the executable, but it can be +/// set to arbitrary text, and might not even exist. This means this property +/// should not be relied upon for security purposes. +/// +/// [`env::args()`]: args +#[must_use = "iterators are lazy and do nothing unless consumed"] +#[stable(feature = "env", since = "1.0.0")] +pub struct Args { + inner: ArgsOs, +} + +/// An iterator over the arguments of a process, yielding an [`OsString`] value +/// for each argument. +/// +/// This struct is created by [`env::args_os()`]. See its documentation +/// for more. +/// +/// The first element is traditionally the path of the executable, but it can be +/// set to arbitrary text, and might not even exist. This means this property +/// should not be relied upon for security purposes. +/// +/// [`env::args_os()`]: args_os +#[must_use = "iterators are lazy and do nothing unless consumed"] +#[stable(feature = "env", since = "1.0.0")] +pub struct ArgsOs { + inner: sys::args::Args, +} + +/// Returns the arguments that this program was started with (normally passed +/// via the command line). +/// +/// The first element is traditionally the path of the executable, but it can be +/// set to arbitrary text, and might not even exist. This means this property should +/// not be relied upon for security purposes. +/// +/// On Unix systems the shell usually expands unquoted arguments with glob patterns +/// (such as `*` and `?`). On Windows this is not done, and such arguments are +/// passed as-is. +/// +/// On glibc Linux systems, arguments are retrieved by placing a function in `.init_array`. +/// glibc passes `argc`, `argv`, and `envp` to functions in `.init_array`, as a non-standard +/// extension. This allows `std::env::args` to work even in a `cdylib` or `staticlib`, as it +/// does on macOS and Windows. +/// +/// # Panics +/// +/// The returned iterator will panic during iteration if any argument to the +/// process is not valid Unicode. If this is not desired, +/// use the [`args_os`] function instead. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// // Prints each argument on a separate line +/// for argument in env::args() { +/// println!("{argument}"); +/// } +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn args() -> Args { + Args { inner: args_os() } +} + +/// Returns the arguments that this program was started with (normally passed +/// via the command line). +/// +/// The first element is traditionally the path of the executable, but it can be +/// set to arbitrary text, and might not even exist. This means this property should +/// not be relied upon for security purposes. +/// +/// On Unix systems the shell usually expands unquoted arguments with glob patterns +/// (such as `*` and `?`). On Windows this is not done, and such arguments are +/// passed as-is. +/// +/// On glibc Linux systems, arguments are retrieved by placing a function in `.init_array`. +/// glibc passes `argc`, `argv`, and `envp` to functions in `.init_array`, as a non-standard +/// extension. This allows `std::env::args_os` to work even in a `cdylib` or `staticlib`, as it +/// does on macOS and Windows. +/// +/// Note that the returned iterator will not check if the arguments to the +/// process are valid Unicode. If you want to panic on invalid UTF-8, +/// use the [`args`] function instead. +/// +/// # Examples +/// +/// ``` +/// use std::env; +/// +/// // Prints each argument on a separate line +/// for argument in env::args_os() { +/// println!("{argument:?}"); +/// } +/// ``` +#[stable(feature = "env", since = "1.0.0")] +pub fn args_os() -> ArgsOs { + ArgsOs { inner: sys::args::args() } +} + +#[stable(feature = "env_unimpl_send_sync", since = "1.26.0")] +impl !Send for Args {} + +#[stable(feature = "env_unimpl_send_sync", since = "1.26.0")] +impl !Sync for Args {} + +#[stable(feature = "env", since = "1.0.0")] +impl Iterator for Args { + type Item = String; + fn next(&mut self) -> Option<String> { + self.inner.next().map(|s| s.into_string().unwrap()) + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.inner.size_hint() + } +} + +#[stable(feature = "env", since = "1.0.0")] +impl ExactSizeIterator for Args { + fn len(&self) -> usize { + self.inner.len() + } + fn is_empty(&self) -> bool { + self.inner.is_empty() + } +} + +#[stable(feature = "env_iterators", since = "1.12.0")] +impl DoubleEndedIterator for Args { + fn next_back(&mut self) -> Option<String> { + self.inner.next_back().map(|s| s.into_string().unwrap()) + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for Args { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("Args").field("inner", &self.inner.inner).finish() + } +} + +#[stable(feature = "env_unimpl_send_sync", since = "1.26.0")] +impl !Send for ArgsOs {} + +#[stable(feature = "env_unimpl_send_sync", since = "1.26.0")] +impl !Sync for ArgsOs {} + +#[stable(feature = "env", since = "1.0.0")] +impl Iterator for ArgsOs { + type Item = OsString; + fn next(&mut self) -> Option<OsString> { + self.inner.next() + } + fn size_hint(&self) -> (usize, Option<usize>) { + self.inner.size_hint() + } +} + +#[stable(feature = "env", since = "1.0.0")] +impl ExactSizeIterator for ArgsOs { + fn len(&self) -> usize { + self.inner.len() + } + fn is_empty(&self) -> bool { + self.inner.is_empty() + } +} + +#[stable(feature = "env_iterators", since = "1.12.0")] +impl DoubleEndedIterator for ArgsOs { + fn next_back(&mut self) -> Option<OsString> { + self.inner.next_back() + } +} + +#[stable(feature = "std_debug", since = "1.16.0")] +impl fmt::Debug for ArgsOs { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + f.debug_struct("ArgsOs").field("inner", &self.inner).finish() + } +} + +/// Constants associated with the current target +#[stable(feature = "env", since = "1.0.0")] +pub mod consts { + use crate::sys::env::os; + + /// A string describing the architecture of the CPU that is currently + /// in use. + /// + /// Some possible values: + /// + /// - x86 + /// - x86_64 + /// - arm + /// - aarch64 + /// - m68k + /// - mips + /// - mips64 + /// - powerpc + /// - powerpc64 + /// - riscv64 + /// - s390x + /// - sparc64 + #[stable(feature = "env", since = "1.0.0")] + pub const ARCH: &str = env!("STD_ENV_ARCH"); + + /// The family of the operating system. Example value is `unix`. + /// + /// Some possible values: + /// + /// - unix + /// - windows + #[stable(feature = "env", since = "1.0.0")] + pub const FAMILY: &str = os::FAMILY; + + /// A string describing the specific operating system in use. + /// Example value is `linux`. + /// + /// Some possible values: + /// + /// - linux + /// - macos + /// - ios + /// - freebsd + /// - dragonfly + /// - netbsd + /// - openbsd + /// - solaris + /// - android + /// - windows + #[stable(feature = "env", since = "1.0.0")] + pub const OS: &str = os::OS; + + /// Specifies the filename prefix used for shared libraries on this + /// platform. Example value is `lib`. + /// + /// Some possible values: + /// + /// - lib + /// - `""` (an empty string) + #[stable(feature = "env", since = "1.0.0")] + pub const DLL_PREFIX: &str = os::DLL_PREFIX; + + /// Specifies the filename suffix used for shared libraries on this + /// platform. Example value is `.so`. + /// + /// Some possible values: + /// + /// - .so + /// - .dylib + /// - .dll + #[stable(feature = "env", since = "1.0.0")] + pub const DLL_SUFFIX: &str = os::DLL_SUFFIX; + + /// Specifies the file extension used for shared libraries on this + /// platform that goes after the dot. Example value is `so`. + /// + /// Some possible values: + /// + /// - so + /// - dylib + /// - dll + #[stable(feature = "env", since = "1.0.0")] + pub const DLL_EXTENSION: &str = os::DLL_EXTENSION; + + /// Specifies the filename suffix used for executable binaries on this + /// platform. Example value is `.exe`. + /// + /// Some possible values: + /// + /// - .exe + /// - .nexe + /// - .pexe + /// - `""` (an empty string) + #[stable(feature = "env", since = "1.0.0")] + pub const EXE_SUFFIX: &str = os::EXE_SUFFIX; + + /// Specifies the file extension, if any, used for executable binaries + /// on this platform. Example value is `exe`. + /// + /// Some possible values: + /// + /// - exe + /// - `""` (an empty string) + #[stable(feature = "env", since = "1.0.0")] + pub const EXE_EXTENSION: &str = os::EXE_EXTENSION; +} |