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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:41:41 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:41:41 +0000 |
commit | 10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87 (patch) | |
tree | bdffd5d80c26cf4a7a518281a204be1ace85b4c1 /vendor/gix-path/src/realpath.rs | |
parent | Releasing progress-linux version 1.70.0+dfsg1-9~progress7.99u1. (diff) | |
download | rustc-10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87.tar.xz rustc-10ee2acdd26a7f1298c6f6d6b7af9b469fe29b87.zip |
Merging upstream version 1.70.0+dfsg2.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/gix-path/src/realpath.rs')
-rw-r--r-- | vendor/gix-path/src/realpath.rs | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/vendor/gix-path/src/realpath.rs b/vendor/gix-path/src/realpath.rs new file mode 100644 index 000000000..807cb74cc --- /dev/null +++ b/vendor/gix-path/src/realpath.rs @@ -0,0 +1,90 @@ +/// The error returned by [`realpath()`][super::realpath()]. +#[derive(Debug, thiserror::Error)] +#[allow(missing_docs)] +pub enum Error { + #[error("The maximum allowed number {} of symlinks in path is exceeded", .max_symlinks)] + MaxSymlinksExceeded { max_symlinks: u8 }, + #[error(transparent)] + ReadLink(std::io::Error), + #[error(transparent)] + CurrentWorkingDir(std::io::Error), + #[error("Empty is not a valid path")] + EmptyPath, + #[error("Ran out of path components while following parent component '..'")] + MissingParent, +} + +/// The default amount of symlinks we may follow when resolving a path in [`realpath()`][crate::realpath()]. +pub const MAX_SYMLINKS: u8 = 32; + +pub(crate) mod function { + use std::path::{ + Component::{CurDir, Normal, ParentDir, Prefix, RootDir}, + Path, PathBuf, + }; + + use super::Error; + use crate::realpath::MAX_SYMLINKS; + + /// Check each component of `path` and see if it is a symlink. If so, resolve it. + /// Do not fail for non-existing components, but assume these are as is. + /// + /// If `path` is relative, the current working directory be used to make it absolute. + pub fn realpath(path: impl AsRef<Path>) -> Result<PathBuf, Error> { + let cwd = path + .as_ref() + .is_relative() + .then(std::env::current_dir) + .unwrap_or_else(|| Ok(PathBuf::default())) + .map_err(Error::CurrentWorkingDir)?; + realpath_opts(path, cwd, MAX_SYMLINKS) + } + + /// The same as [`realpath()`], but allow to configure `max_symlinks` to configure how many symbolic links we are going to follow. + /// This serves to avoid running into cycles or doing unreasonable amounts of work. + pub fn realpath_opts(path: impl AsRef<Path>, cwd: impl AsRef<Path>, max_symlinks: u8) -> Result<PathBuf, Error> { + let path = path.as_ref(); + if path.as_os_str().is_empty() { + return Err(Error::EmptyPath); + } + + let mut real_path = PathBuf::new(); + if path.is_relative() { + real_path.push(cwd); + } + + let mut num_symlinks = 0; + let mut path_backing: PathBuf; + let mut components = path.components(); + while let Some(component) = components.next() { + match component { + part @ RootDir | part @ Prefix(_) => real_path.push(part), + CurDir => {} + ParentDir => { + if !real_path.pop() { + return Err(Error::MissingParent); + } + } + Normal(part) => { + real_path.push(part); + if real_path.is_symlink() { + num_symlinks += 1; + if num_symlinks > max_symlinks { + return Err(Error::MaxSymlinksExceeded { max_symlinks }); + } + let mut link_destination = std::fs::read_link(real_path.as_path()).map_err(Error::ReadLink)?; + if link_destination.is_absolute() { + // pushing absolute path to real_path resets it to the pushed absolute path + } else { + assert!(real_path.pop(), "we just pushed a component"); + } + link_destination.extend(components); + path_backing = link_destination; + components = path_backing.components(); + } + } + } + } + Ok(real_path) + } +} |