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Diffstat (limited to 'third_party/rust/tempfile/src/lib.rs')
| -rw-r--r-- | third_party/rust/tempfile/src/lib.rs | 701 |
1 files changed, 701 insertions, 0 deletions
diff --git a/third_party/rust/tempfile/src/lib.rs b/third_party/rust/tempfile/src/lib.rs new file mode 100644 index 0000000000..4b6371d49f --- /dev/null +++ b/third_party/rust/tempfile/src/lib.rs @@ -0,0 +1,701 @@ +//! Temporary files and directories. +//! +//! - Use the [`tempfile()`] function for temporary files +//! - Use the [`tempdir()`] function for temporary directories. +//! +//! # Design +//! +//! This crate provides several approaches to creating temporary files and directories. +//! [`tempfile()`] relies on the OS to remove the temporary file once the last handle is closed. +//! [`TempDir`] and [`NamedTempFile`] both rely on Rust destructors for cleanup. +//! +//! When choosing between the temporary file variants, prefer `tempfile` +//! unless you either need to know the file's path or to be able to persist it. +//! +//! ## Resource Leaking +//! +//! `tempfile` will (almost) never fail to cleanup temporary resources. However `TempDir` and `NamedTempFile` will +//! fail if their destructors don't run. This is because `tempfile` relies on the OS to cleanup the +//! underlying file, while `TempDir` and `NamedTempFile` rely on rust destructors to do so. +//! Destructors may fail to run if the process exits through an unhandled signal interrupt (like `SIGINT`), +//! or if the instance is declared statically (like with [`lazy_static`]), among other possible +//! reasons. +//! +//! ## Security +//! +//! In the presence of pathological temporary file cleaner, relying on file paths is unsafe because +//! a temporary file cleaner could delete the temporary file which an attacker could then replace. +//! +//! `tempfile` doesn't rely on file paths so this isn't an issue. However, `NamedTempFile` does +//! rely on file paths for _some_ operations. See the security documentation on +//! the `NamedTempFile` type for more information. +//! +//! ## Early drop pitfall +//! +//! Because `TempDir` and `NamedTempFile` rely on their destructors for cleanup, this can lead +//! to an unexpected early removal of the directory/file, usually when working with APIs which are +//! generic over `AsRef<Path>`. Consider the following example: +//! +//! ```no_run +//! # use tempfile::tempdir; +//! # use std::io; +//! # use std::process::Command; +//! # fn main() { +//! # if let Err(_) = run() { +//! # ::std::process::exit(1); +//! # } +//! # } +//! # fn run() -> Result<(), io::Error> { +//! // Create a directory inside of `std::env::temp_dir()`. +//! let temp_dir = tempdir()?; +//! +//! // Spawn the `touch` command inside the temporary directory and collect the exit status +//! // Note that `temp_dir` is **not** moved into `current_dir`, but passed as a reference +//! let exit_status = Command::new("touch").arg("tmp").current_dir(&temp_dir).status()?; +//! assert!(exit_status.success()); +//! +//! # Ok(()) +//! # } +//! ``` +//! +//! This works because a reference to `temp_dir` is passed to `current_dir`, resulting in the +//! destructor of `temp_dir` being run after the `Command` has finished execution. Moving the +//! `TempDir` into the `current_dir` call would result in the `TempDir` being converted into +//! an internal representation, with the original value being dropped and the directory thus +//! being deleted, before the command can be executed. +//! +//! The `touch` command would fail with an `No such file or directory` error. +//! +//! ## Examples +//! +//! Create a temporary file and write some data into it: +//! +//! ``` +//! use tempfile::tempfile; +//! use std::io::{self, Write}; +//! +//! # fn main() { +//! # if let Err(_) = run() { +//! # ::std::process::exit(1); +//! # } +//! # } +//! # fn run() -> Result<(), io::Error> { +//! // Create a file inside of `std::env::temp_dir()`. +//! let mut file = tempfile()?; +//! +//! writeln!(file, "Brian was here. Briefly.")?; +//! # Ok(()) +//! # } +//! ``` +//! +//! Create a named temporary file and open an independent file handle: +//! +//! ``` +//! use tempfile::NamedTempFile; +//! use std::io::{self, Write, Read}; +//! +//! # fn main() { +//! # if let Err(_) = run() { +//! # ::std::process::exit(1); +//! # } +//! # } +//! # fn run() -> Result<(), io::Error> { +//! let text = "Brian was here. Briefly."; +//! +//! // Create a file inside of `std::env::temp_dir()`. +//! let mut file1 = NamedTempFile::new()?; +//! +//! // Re-open it. +//! let mut file2 = file1.reopen()?; +//! +//! // Write some test data to the first handle. +//! file1.write_all(text.as_bytes())?; +//! +//! // Read the test data using the second handle. +//! let mut buf = String::new(); +//! file2.read_to_string(&mut buf)?; +//! assert_eq!(buf, text); +//! # Ok(()) +//! # } +//! ``` +//! +//! Create a temporary directory and add a file to it: +//! +//! ``` +//! use tempfile::tempdir; +//! use std::fs::File; +//! use std::io::{self, Write}; +//! +//! # fn main() { +//! # if let Err(_) = run() { +//! # ::std::process::exit(1); +//! # } +//! # } +//! # fn run() -> Result<(), io::Error> { +//! // Create a directory inside of `std::env::temp_dir()`. +//! let dir = tempdir()?; +//! +//! let file_path = dir.path().join("my-temporary-note.txt"); +//! let mut file = File::create(file_path)?; +//! writeln!(file, "Brian was here. Briefly.")?; +//! +//! // By closing the `TempDir` explicitly, we can check that it has +//! // been deleted successfully. If we don't close it explicitly, +//! // the directory will still be deleted when `dir` goes out +//! // of scope, but we won't know whether deleting the directory +//! // succeeded. +//! drop(file); +//! dir.close()?; +//! # Ok(()) +//! # } +//! ``` +//! +//! [`tempfile()`]: fn.tempfile.html +//! [`tempdir()`]: fn.tempdir.html +//! [`TempDir`]: struct.TempDir.html +//! [`NamedTempFile`]: struct.NamedTempFile.html +//! [`std::env::temp_dir()`]: https://doc.rust-lang.org/std/env/fn.temp_dir.html +//! [`lazy_static`]: https://github.com/rust-lang-nursery/lazy-static.rs/issues/62 + +#![doc( + html_logo_url = "https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png", + html_favicon_url = "https://www.rust-lang.org/favicon.ico", + html_root_url = "https://docs.rs/tempfile/3.1.0" +)] +#![cfg_attr(test, deny(warnings))] +#![deny(rust_2018_idioms)] +#![allow(clippy::redundant_field_names)] +#![cfg_attr(all(feature = "nightly", target_os = "wasi"), feature(wasi_ext))] + +#[cfg(doctest)] +doc_comment::doctest!("../README.md"); + +const NUM_RETRIES: u32 = 1 << 31; +const NUM_RAND_CHARS: usize = 6; + +use std::ffi::OsStr; +use std::fs::OpenOptions; +use std::path::Path; +use std::{env, io}; + +mod dir; +mod error; +mod file; +mod spooled; +mod util; + +pub use crate::dir::{tempdir, tempdir_in, TempDir}; +pub use crate::file::{ + tempfile, tempfile_in, NamedTempFile, PathPersistError, PersistError, TempPath, +}; +pub use crate::spooled::{spooled_tempfile, SpooledTempFile}; + +/// Create a new temporary file or directory with custom parameters. +#[derive(Debug, Clone, Eq, PartialEq)] +pub struct Builder<'a, 'b> { + random_len: usize, + prefix: &'a OsStr, + suffix: &'b OsStr, + append: bool, +} + +impl<'a, 'b> Default for Builder<'a, 'b> { + fn default() -> Self { + Builder { + random_len: crate::NUM_RAND_CHARS, + prefix: OsStr::new(".tmp"), + suffix: OsStr::new(""), + append: false, + } + } +} + +impl<'a, 'b> Builder<'a, 'b> { + /// Create a new `Builder`. + /// + /// # Examples + /// + /// Create a named temporary file and write some data into it: + /// + /// ``` + /// # use std::io; + /// # use std::ffi::OsStr; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// use tempfile::Builder; + /// + /// let named_tempfile = Builder::new() + /// .prefix("my-temporary-note") + /// .suffix(".txt") + /// .rand_bytes(5) + /// .tempfile()?; + /// + /// let name = named_tempfile + /// .path() + /// .file_name().and_then(OsStr::to_str); + /// + /// if let Some(name) = name { + /// assert!(name.starts_with("my-temporary-note")); + /// assert!(name.ends_with(".txt")); + /// assert_eq!(name.len(), "my-temporary-note.txt".len() + 5); + /// } + /// # Ok(()) + /// # } + /// ``` + /// + /// Create a temporary directory and add a file to it: + /// + /// ``` + /// # use std::io::{self, Write}; + /// # use std::fs::File; + /// # use std::ffi::OsStr; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// use tempfile::Builder; + /// + /// let dir = Builder::new() + /// .prefix("my-temporary-dir") + /// .rand_bytes(5) + /// .tempdir()?; + /// + /// let file_path = dir.path().join("my-temporary-note.txt"); + /// let mut file = File::create(file_path)?; + /// writeln!(file, "Brian was here. Briefly.")?; + /// + /// // By closing the `TempDir` explicitly, we can check that it has + /// // been deleted successfully. If we don't close it explicitly, + /// // the directory will still be deleted when `dir` goes out + /// // of scope, but we won't know whether deleting the directory + /// // succeeded. + /// drop(file); + /// dir.close()?; + /// # Ok(()) + /// # } + /// ``` + /// + /// Create a temporary directory with a chosen prefix under a chosen folder: + /// + /// ```ignore + /// let dir = Builder::new() + /// .prefix("my-temporary-dir") + /// .tempdir_in("folder-with-tempdirs")?; + /// ``` + #[must_use] + pub fn new() -> Self { + Self::default() + } + + /// Set a custom filename prefix. + /// + /// Path separators are legal but not advisable. + /// Default: `.tmp`. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let named_tempfile = Builder::new() + /// .prefix("my-temporary-note") + /// .tempfile()?; + /// # Ok(()) + /// # } + /// ``` + pub fn prefix<S: AsRef<OsStr> + ?Sized>(&mut self, prefix: &'a S) -> &mut Self { + self.prefix = prefix.as_ref(); + self + } + + /// Set a custom filename suffix. + /// + /// Path separators are legal but not advisable. + /// Default: empty. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let named_tempfile = Builder::new() + /// .suffix(".txt") + /// .tempfile()?; + /// # Ok(()) + /// # } + /// ``` + pub fn suffix<S: AsRef<OsStr> + ?Sized>(&mut self, suffix: &'b S) -> &mut Self { + self.suffix = suffix.as_ref(); + self + } + + /// Set the number of random bytes. + /// + /// Default: `6`. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let named_tempfile = Builder::new() + /// .rand_bytes(5) + /// .tempfile()?; + /// # Ok(()) + /// # } + /// ``` + pub fn rand_bytes(&mut self, rand: usize) -> &mut Self { + self.random_len = rand; + self + } + + /// Set the file to be opened in append mode. + /// + /// Default: `false`. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let named_tempfile = Builder::new() + /// .append(true) + /// .tempfile()?; + /// # Ok(()) + /// # } + /// ``` + pub fn append(&mut self, append: bool) -> &mut Self { + self.append = append; + self + } + + /// Create the named temporary file. + /// + /// # Security + /// + /// See [the security][security] docs on `NamedTempFile`. + /// + /// # Resource leaking + /// + /// See [the resource leaking][resource-leaking] docs on `NamedTempFile`. + /// + /// # Errors + /// + /// If the file cannot be created, `Err` is returned. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let tempfile = Builder::new().tempfile()?; + /// # Ok(()) + /// # } + /// ``` + /// + /// [security]: struct.NamedTempFile.html#security + /// [resource-leaking]: struct.NamedTempFile.html#resource-leaking + pub fn tempfile(&self) -> io::Result<NamedTempFile> { + self.tempfile_in(env::temp_dir()) + } + + /// Create the named temporary file in the specified directory. + /// + /// # Security + /// + /// See [the security][security] docs on `NamedTempFile`. + /// + /// # Resource leaking + /// + /// See [the resource leaking][resource-leaking] docs on `NamedTempFile`. + /// + /// # Errors + /// + /// If the file cannot be created, `Err` is returned. + /// + /// # Examples + /// + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// let tempfile = Builder::new().tempfile_in("./")?; + /// # Ok(()) + /// # } + /// ``` + /// + /// [security]: struct.NamedTempFile.html#security + /// [resource-leaking]: struct.NamedTempFile.html#resource-leaking + pub fn tempfile_in<P: AsRef<Path>>(&self, dir: P) -> io::Result<NamedTempFile> { + util::create_helper( + dir.as_ref(), + self.prefix, + self.suffix, + self.random_len, + |path| file::create_named(path, OpenOptions::new().append(self.append)), + ) + } + + /// Attempts to make a temporary directory inside of `env::temp_dir()` whose + /// name will have the prefix, `prefix`. The directory and + /// everything inside it will be automatically deleted once the + /// returned `TempDir` is destroyed. + /// + /// # Resource leaking + /// + /// See [the resource leaking][resource-leaking] docs on `TempDir`. + /// + /// # Errors + /// + /// If the directory can not be created, `Err` is returned. + /// + /// # Examples + /// + /// ``` + /// use std::fs::File; + /// use std::io::Write; + /// use tempfile::Builder; + /// + /// # use std::io; + /// # fn run() -> Result<(), io::Error> { + /// let tmp_dir = Builder::new().tempdir()?; + /// # Ok(()) + /// # } + /// ``` + /// + /// [resource-leaking]: struct.TempDir.html#resource-leaking + pub fn tempdir(&self) -> io::Result<TempDir> { + self.tempdir_in(env::temp_dir()) + } + + /// Attempts to make a temporary directory inside of `dir`. + /// The directory and everything inside it will be automatically + /// deleted once the returned `TempDir` is destroyed. + /// + /// # Resource leaking + /// + /// See [the resource leaking][resource-leaking] docs on `TempDir`. + /// + /// # Errors + /// + /// If the directory can not be created, `Err` is returned. + /// + /// # Examples + /// + /// ``` + /// use std::fs::{self, File}; + /// use std::io::Write; + /// use tempfile::Builder; + /// + /// # use std::io; + /// # fn run() -> Result<(), io::Error> { + /// let tmp_dir = Builder::new().tempdir_in("./")?; + /// # Ok(()) + /// # } + /// ``` + /// + /// [resource-leaking]: struct.TempDir.html#resource-leaking + pub fn tempdir_in<P: AsRef<Path>>(&self, dir: P) -> io::Result<TempDir> { + let storage; + let mut dir = dir.as_ref(); + if !dir.is_absolute() { + let cur_dir = env::current_dir()?; + storage = cur_dir.join(dir); + dir = &storage; + } + + util::create_helper(dir, self.prefix, self.suffix, self.random_len, dir::create) + } + + /// Attempts to create a temporary file (or file-like object) using the + /// provided closure. The closure is passed a temporary file path and + /// returns an [`std::io::Result`]. The path provided to the closure will be + /// inside of [`std::env::temp_dir()`]. Use [`Builder::make_in`] to provide + /// a custom temporary directory. If the closure returns one of the + /// following errors, then another randomized file path is tried: + /// - [`std::io::ErrorKind::AlreadyExists`] + /// - [`std::io::ErrorKind::AddrInUse`] + /// + /// This can be helpful for taking full control over the file creation, but + /// leaving the temporary file path construction up to the library. This + /// also enables creating a temporary UNIX domain socket, since it is not + /// possible to bind to a socket that already exists. + /// + /// Note that [`Builder::append`] is ignored when using [`Builder::make`]. + /// + /// # Security + /// + /// This has the same [security implications][security] as + /// [`NamedTempFile`], but with additional caveats. Specifically, it is up + /// to the closure to ensure that the file does not exist and that such a + /// check is *atomic*. Otherwise, a [time-of-check to time-of-use + /// bug][TOCTOU] could be introduced. + /// + /// For example, the following is **not** secure: + /// + /// ``` + /// # use std::io; + /// # use std::fs::File; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// // This is NOT secure! + /// let tempfile = Builder::new().make(|path| { + /// if path.is_file() { + /// return Err(io::ErrorKind::AlreadyExists.into()); + /// } + /// + /// // Between the check above and the usage below, an attacker could + /// // have replaced `path` with another file, which would get truncated + /// // by `File::create`. + /// + /// File::create(path) + /// })?; + /// # Ok(()) + /// # } + /// ``` + /// Note that simply using [`std::fs::File::create`] alone is not correct + /// because it does not fail if the file already exists: + /// ``` + /// # use std::io; + /// # use std::fs::File; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// // This could overwrite an existing file! + /// let tempfile = Builder::new().make(|path| File::create(path))?; + /// # Ok(()) + /// # } + /// ``` + /// For creating regular temporary files, use [`Builder::tempfile`] instead + /// to avoid these problems. This function is meant to enable more exotic + /// use-cases. + /// + /// # Resource leaking + /// + /// See [the resource leaking][resource-leaking] docs on `NamedTempFile`. + /// + /// # Errors + /// + /// If the closure returns any error besides + /// [`std::io::ErrorKind::AlreadyExists`] or + /// [`std::io::ErrorKind::AddrInUse`], then `Err` is returned. + /// + /// # Examples + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// # #[cfg(unix)] + /// use std::os::unix::net::UnixListener; + /// # #[cfg(unix)] + /// let tempsock = Builder::new().make(|path| UnixListener::bind(path))?; + /// # Ok(()) + /// # } + /// ``` + /// + /// [TOCTOU]: https://en.wikipedia.org/wiki/Time-of-check_to_time-of-use + /// [security]: struct.NamedTempFile.html#security + /// [resource-leaking]: struct.NamedTempFile.html#resource-leaking + pub fn make<F, R>(&self, f: F) -> io::Result<NamedTempFile<R>> + where + F: FnMut(&Path) -> io::Result<R>, + { + self.make_in(env::temp_dir(), f) + } + + /// This is the same as [`Builder::make`], except `dir` is used as the base + /// directory for the temporary file path. + /// + /// See [`Builder::make`] for more details and security implications. + /// + /// # Examples + /// ``` + /// # use std::io; + /// # fn main() { + /// # if let Err(_) = run() { + /// # ::std::process::exit(1); + /// # } + /// # } + /// # fn run() -> Result<(), io::Error> { + /// # use tempfile::Builder; + /// # #[cfg(unix)] + /// use std::os::unix::net::UnixListener; + /// # #[cfg(unix)] + /// let tempsock = Builder::new().make_in("./", |path| UnixListener::bind(path))?; + /// # Ok(()) + /// # } + /// ``` + pub fn make_in<F, R, P>(&self, dir: P, mut f: F) -> io::Result<NamedTempFile<R>> + where + F: FnMut(&Path) -> io::Result<R>, + P: AsRef<Path>, + { + util::create_helper( + dir.as_ref(), + self.prefix, + self.suffix, + self.random_len, + move |path| { + Ok(NamedTempFile::from_parts( + f(&path)?, + TempPath::from_path(path), + )) + }, + ) + } +} |