Auto merge of #11866 - Zoxc:fs-non-canon, r=ehuss

Add `try_canonicalize` and use it over `std::fs::canonicalize`

This adds a `try_canonicalize` function that calls `std::fs::canonicalize` and on Windows falls back to getting an absolute path. Uses of `canonicalize` have been replaced with `std::fs::canonicalize`. On Windows `std::fs::canonicalize` may fail due to incomplete drivers. In particular `ImDisk` does not support it.

Combined with https://github.com/rust-lang/rust/pull/109231 this allows compiling crates on an `ImDisk` RAM disk and I've tested that it works with various configuration using [rcb](https://github.com/Zoxc/rcb).

src/cargo/core/compiler/compile_kind.rs

@@ -3,7 +3,7 @@
 use crate::core::Target;
 use crate::util::errors::CargoResult;
 use crate::util::interning::InternedString;
-use crate::util::{Config, StableHasher};
+use crate::util::{try_canonicalize, Config, StableHasher};
 use anyhow::Context as _;
 use serde::Serialize;
 use std::collections::BTreeSet;
@@ -138,8 +138,7 @@ impl CompileTarget {
         // If `name` ends in `.json` then it's likely a custom target
         // specification. Canonicalize the path to ensure that different builds
         // with different paths always produce the same result.
-        let path = Path::new(name)
-            .canonicalize()
+        let path = try_canonicalize(Path::new(name))
             .with_context(|| format!("target path {:?} is not a valid file", name))?;
 
         let name = path

src/cargo/core/compiler/fingerprint/mod.rs

@@ -367,9 +367,9 @@ use serde::{Deserialize, Serialize};
 
 use crate::core::compiler::unit_graph::UnitDep;
 use crate::core::Package;
-use crate::util;
 use crate::util::errors::CargoResult;
 use crate::util::interning::InternedString;
+use crate::util::{self, try_canonicalize};
 use crate::util::{internal, path_args, profile, StableHasher};
 use crate::{Config, CARGO_ENV};
 
@@ -1951,8 +1951,8 @@ pub fn translate_dep_info(
 ) -> CargoResult<()> {
     let depinfo = parse_rustc_dep_info(rustc_dep_info)?;
 
-    let target_root = target_root.canonicalize()?;
-    let pkg_root = pkg_root.canonicalize()?;
+    let target_root = try_canonicalize(target_root)?;
+    let pkg_root = try_canonicalize(pkg_root)?;
     let mut on_disk_info = EncodedDepInfo::default();
     on_disk_info.env = depinfo.env;
 
@@ -1995,7 +1995,7 @@ pub fn translate_dep_info(
         // If canonicalization fails, just use the abs path. There is currently
         // a bug where --remap-path-prefix is affecting .d files, causing them
         // to point to non-existent paths.
-        let canon_file = abs_file.canonicalize().unwrap_or_else(|_| abs_file.clone());
+        let canon_file = try_canonicalize(&abs_file).unwrap_or_else(|_| abs_file.clone());
 
         let (ty, path) = if let Ok(stripped) = canon_file.strip_prefix(&target_root) {
             (DepInfoPathType::TargetRootRelative, stripped)

src/cargo/ops/vendor.rs

@@ -4,7 +4,7 @@ use crate::core::{GitReference, Package, Workspace};
 use crate::ops;
 use crate::sources::path::PathSource;
 use crate::sources::CRATES_IO_REGISTRY;
-use crate::util::{CargoResult, Config};
+use crate::util::{try_canonicalize, CargoResult, Config};
 use anyhow::{bail, Context as _};
 use cargo_util::{paths, Sha256};
 use serde::Serialize;
@@ -83,7 +83,7 @@ fn sync(
     workspaces: &[&Workspace<'_>],
     opts: &VendorOptions<'_>,
 ) -> CargoResult<VendorConfig> {
-    let canonical_destination = opts.destination.canonicalize();
+    let canonical_destination = try_canonicalize(opts.destination);
     let canonical_destination = canonical_destination.as_deref().unwrap_or(opts.destination);
     let dest_dir_already_exists = canonical_destination.exists();
 
@@ -125,7 +125,7 @@ fn sync(
             // Don't delete actual source code!
             if pkg.source_id().is_path() {
                 if let Ok(path) = pkg.source_id().url().to_file_path() {
-                    if let Ok(path) = path.canonicalize() {
+                    if let Ok(path) = try_canonicalize(path) {
                         to_remove.remove(&path);
                     }
                 }

src/cargo/util/config/mod.rs

@@ -72,9 +72,9 @@ use crate::core::{features, CliUnstable, Shell, SourceId, Workspace, WorkspaceRo
 use crate::ops::{self, RegistryCredentialConfig};
 use crate::util::auth::Secret;
 use crate::util::errors::CargoResult;
-use crate::util::validate_package_name;
 use crate::util::CanonicalUrl;
 use crate::util::{internal, toml as cargo_toml};
+use crate::util::{try_canonicalize, validate_package_name};
 use crate::util::{FileLock, Filesystem, IntoUrl, IntoUrlWithBase, Rustc};
 use anyhow::{anyhow, bail, format_err, Context as _};
 use cargo_util::paths;
@@ -433,11 +433,11 @@ impl Config {
                     // commands that use Cargo as a library to inherit (via `cargo <subcommand>`)
                     // or set (by setting `$CARGO`) a correct path to `cargo` when the current exe
                     // is not actually cargo (e.g., `cargo-*` binaries, Valgrind, `ld.so`, etc.).
-                    let exe = self
-                        .get_env_os(crate::CARGO_ENV)
-                        .map(PathBuf::from)
-                        .ok_or_else(|| anyhow!("$CARGO not set"))?
-                        .canonicalize()?;
+                    let exe = try_canonicalize(
+                        self.get_env_os(crate::CARGO_ENV)
+                            .map(PathBuf::from)
+                            .ok_or_else(|| anyhow!("$CARGO not set"))?,
+                    )?;
                     Ok(exe)
                 };
 
@@ -446,7 +446,7 @@ impl Config {
                     // The method varies per operating system and might fail; in particular,
                     // it depends on `/proc` being mounted on Linux, and some environments
                     // (like containers or chroots) may not have that available.
-                    let exe = env::current_exe()?.canonicalize()?;
+                    let exe = try_canonicalize(env::current_exe()?)?;
                     Ok(exe)
                 }
 

src/cargo/util/mod.rs

@@ -1,4 +1,5 @@
 use std::fmt;
+use std::path::{Path, PathBuf};
 use std::time::Duration;
 
 pub use self::canonical_url::CanonicalUrl;
@@ -133,6 +134,79 @@ pub fn truncate_with_ellipsis(s: &str, max_width: usize) -> String {
     prefix
 }
 
+#[cfg(not(windows))]
+#[inline]
+pub fn try_canonicalize<P: AsRef<Path>>(path: P) -> std::io::Result<PathBuf> {
+    std::fs::canonicalize(&path)
+}
+
+#[cfg(windows)]
+#[inline]
+pub fn try_canonicalize<P: AsRef<Path>>(path: P) -> std::io::Result<PathBuf> {
+    use std::ffi::OsString;
+    use std::io::Error;
+    use std::os::windows::ffi::{OsStrExt, OsStringExt};
+    use std::{io::ErrorKind, ptr};
+    use windows_sys::Win32::Foundation::{GetLastError, SetLastError};
+    use windows_sys::Win32::Storage::FileSystem::GetFullPathNameW;
+
+    // On Windows `canonicalize` may fail, so we fall back to getting an absolute path.
+    std::fs::canonicalize(&path).or_else(|_| {
+        // Return an error if a file does not exist for better compatiblity with `canonicalize`
+        if !path.as_ref().try_exists()? {
+            return Err(Error::new(ErrorKind::NotFound, "the path was not found"));
+        }
+
+        // This code is based on the unstable `std::path::absolute` and could be replaced with it
+        // if it's stabilized.
+
+        let path = path.as_ref().as_os_str();
+        let mut path_u16 = Vec::with_capacity(path.len() + 1);
+        path_u16.extend(path.encode_wide());
+        if path_u16.iter().find(|c| **c == 0).is_some() {
+            return Err(Error::new(
+                ErrorKind::InvalidInput,
+                "strings passed to WinAPI cannot contain NULs",
+            ));
+        }
+        path_u16.push(0);
+
+        loop {
+            unsafe {
+                SetLastError(0);
+                let len =
+                    GetFullPathNameW(path_u16.as_ptr(), 0, &mut [] as *mut u16, ptr::null_mut());
+                if len == 0 {
+                    let error = GetLastError();
+                    if error != 0 {
+                        return Err(Error::from_raw_os_error(error as i32));
+                    }
+                }
+                let mut result = vec![0u16; len as usize];
+
+                let write_len = GetFullPathNameW(
+                    path_u16.as_ptr(),
+                    result.len().try_into().unwrap(),
+                    result.as_mut_ptr().cast::<u16>(),
+                    ptr::null_mut(),
+                );
+                if write_len == 0 {
+                    let error = GetLastError();
+                    if error != 0 {
+                        return Err(Error::from_raw_os_error(error as i32));
+                    }
+                }
+
+                if write_len <= len {
+                    return Ok(PathBuf::from(OsString::from_wide(
+                        &result[0..(write_len as usize)],
+                    )));
+                }
+            }
+        }
+    })
+}
+
 #[cfg(test)]
 mod test {
     use super::*;