compiler/rustc_session/src/filesearch.rs - rust-lang/rust - Git at Google

 //! A module for searching for libraries

 use std::path::{Path, PathBuf};
 use std::{env, fs};

 use rustc_fs_util::try_canonicalize;
 use rustc_target::spec::Target;

 use crate::search_paths::{PathKind, SearchPath};

 #[derive(Clone)]
 pub struct FileSearch {
     cli_search_paths: Vec<SearchPath>,
     tlib_path: SearchPath,
 }

 impl FileSearch {
     pub fn cli_search_paths<'b>(&'b self, kind: PathKind) -> impl Iterator<Item = &'b SearchPath> {
         self.cli_search_paths.iter().filter(move |sp| sp.kind.matches(kind))
     }

     pub fn search_paths<'b>(&'b self, kind: PathKind) -> impl Iterator<Item = &'b SearchPath> {
         self.cli_search_paths
             .iter()
             .filter(move |sp| sp.kind.matches(kind))
             .chain(std::iter::once(&self.tlib_path))
     }

     pub fn new(cli_search_paths: &[SearchPath], tlib_path: &SearchPath, target: &Target) -> Self {
         let this = FileSearch {
             cli_search_paths: cli_search_paths.to_owned(),
             tlib_path: tlib_path.clone(),
         };
         this.refine(&["lib", &target.staticlib_prefix, &target.dll_prefix])
     }
     // Produce a new file search from this search that has a smaller set of candidates.
     fn refine(mut self, allowed_prefixes: &[&str]) -> FileSearch {
         self.cli_search_paths
             .iter_mut()
             .for_each(|search_paths| search_paths.files.retain(allowed_prefixes));
         self.tlib_path.files.retain(allowed_prefixes);

         self
     }
 }

 pub fn make_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
     let rustlib_path = rustc_target::relative_target_rustlib_path(sysroot, target_triple);
     sysroot.join(rustlib_path).join("lib")
 }

 /// Returns a path to the target's `bin` folder within its `rustlib` path in the sysroot. This is
 /// where binaries are usually installed, e.g. the self-contained linkers, lld-wrappers, LLVM tools,
 /// etc.
 pub fn make_target_bin_path(sysroot: &Path, target_triple: &str) -> PathBuf {
     let rustlib_path = rustc_target::relative_target_rustlib_path(sysroot, target_triple);
     sysroot.join(rustlib_path).join("bin")
 }

 #[cfg(unix)]
 fn current_dll_path() -> Result<PathBuf, String> {
     use std::sync::OnceLock;

     // This is somewhat expensive relative to other work when compiling `fn main() {}` as `dladdr`
     // needs to iterate over the symbol table of librustc_driver.so until it finds a match.
     // As such cache this to avoid recomputing if we try to get the sysroot in multiple places.
     static CURRENT_DLL_PATH: OnceLock<Result<PathBuf, String>> = OnceLock::new();
     CURRENT_DLL_PATH
         .get_or_init(|| {
             use std::ffi::{CStr, OsStr};
             use std::os::unix::prelude::*;

             #[cfg(not(target_os = "aix"))]
             unsafe {
                 let addr = current_dll_path as usize as *mut _;
                 let mut info = std::mem::zeroed();
                 if libc::dladdr(addr, &mut info) == 0 {
                     return Err("dladdr failed".into());
                 }
                 #[cfg(target_os = "cygwin")]
                 let fname_ptr = info.dli_fname.as_ptr();
                 #[cfg(not(target_os = "cygwin"))]
                 let fname_ptr = {
                     assert!(!info.dli_fname.is_null(), "dli_fname cannot be null");
                     info.dli_fname
                 };
                 let bytes = CStr::from_ptr(fname_ptr).to_bytes();
                 let os = OsStr::from_bytes(bytes);
                 try_canonicalize(Path::new(os)).map_err(|e| e.to_string())
             }

             #[cfg(target_os = "aix")]
             unsafe {
                 // On AIX, the symbol `current_dll_path` references a function descriptor.
                 // A function descriptor is consisted of (See https://reviews.llvm.org/D62532)
                 // * The address of the entry point of the function.
                 // * The TOC base address for the function.
                 // * The environment pointer.
                 // The function descriptor is in the data section.
                 let addr = current_dll_path as u64;
                 let mut buffer = vec![std::mem::zeroed::<libc::ld_info>(); 64];
                 loop {
                     if libc::loadquery(
                         libc::L_GETINFO,
                         buffer.as_mut_ptr() as *mut u8,
                         (size_of::<libc::ld_info>() * buffer.len()) as u32,
                     ) >= 0
                     {
                         break;
                     } else {
                         if std::io::Error::last_os_error().raw_os_error().unwrap() != libc::ENOMEM {
                             return Err("loadquery failed".into());
                         }
                         buffer.resize(buffer.len() * 2, std::mem::zeroed::<libc::ld_info>());
                     }
                 }
                 let mut current = buffer.as_mut_ptr() as *mut libc::ld_info;
                 loop {
                     let data_base = (*current).ldinfo_dataorg as u64;
                     let data_end = data_base + (*current).ldinfo_datasize;
                     if (data_base..data_end).contains(&addr) {
                         let bytes = CStr::from_ptr(&(*current).ldinfo_filename[0]).to_bytes();
                         let os = OsStr::from_bytes(bytes);
                         return try_canonicalize(Path::new(os)).map_err(|e| e.to_string());
                     }
                     if (*current).ldinfo_next == 0 {
                         break;
                     }
                     current = (current as *mut i8).offset((*current).ldinfo_next as isize)
                         as *mut libc::ld_info;
                 }
                 return Err(format!("current dll's address {} is not in the load map", addr));
             }
         })
         .clone()
 }

 #[cfg(windows)]
 fn current_dll_path() -> Result<PathBuf, String> {
     use std::ffi::OsString;
     use std::io;
     use std::os::windows::prelude::*;

     use windows::Win32::Foundation::HMODULE;
     use windows::Win32::System::LibraryLoader::{
         GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS, GetModuleFileNameW, GetModuleHandleExW,
     };
     use windows::core::PCWSTR;

     let mut module = HMODULE::default();
     unsafe {
         GetModuleHandleExW(
             GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
             PCWSTR(current_dll_path as *mut u16),
             &mut module,
         )
     }
     .map_err(|e| e.to_string())?;

     let mut filename = vec![0; 1024];
     let n = unsafe { GetModuleFileNameW(Some(module), &mut filename) } as usize;
     if n == 0 {
         return Err(format!("GetModuleFileNameW failed: {}", io::Error::last_os_error()));
     }
     if n >= filename.capacity() {
         return Err(format!("our buffer was too small? {}", io::Error::last_os_error()));
     }

     filename.truncate(n);

     let path = try_canonicalize(OsString::from_wide(&filename)).map_err(|e| e.to_string())?;

     // See comments on this target function, but the gist is that
     // gcc chokes on verbatim paths which fs::canonicalize generates
     // so we try to avoid those kinds of paths.
     Ok(rustc_fs_util::fix_windows_verbatim_for_gcc(&path))
 }

 #[cfg(target_os = "wasi")]
 fn current_dll_path() -> Result<PathBuf, String> {
     Err("current_dll_path is not supported on WASI".to_string())
 }

 /// This function checks if sysroot is found using env::args().next(), and if it
 /// is not found, finds sysroot from current rustc_driver dll.
 pub(crate) fn default_sysroot() -> PathBuf {
     fn default_from_rustc_driver_dll() -> Result<PathBuf, String> {
         let dll = current_dll_path()?;

         // `dll` will be in one of the following two:
         // - compiler's libdir: $sysroot/lib/*.dll
         // - target's libdir: $sysroot/lib/rustlib/$target/lib/*.dll
         //
         // use `parent` twice to chop off the file name and then also the
         // directory containing the dll
         let dir = dll.parent().and_then(|p| p.parent()).ok_or_else(|| {
             format!("Could not move 2 levels upper using `parent()` on {}", dll.display())
         })?;

         // if `dir` points to target's dir, move up to the sysroot
         let mut sysroot_dir = if dir.ends_with(crate::config::host_tuple()) {
             dir.parent() // chop off `$target`
                 .and_then(|p| p.parent()) // chop off `rustlib`
                 .and_then(|p| p.parent()) // chop off `lib`
                 .map(|s| s.to_owned())
                 .ok_or_else(|| {
                     format!("Could not move 3 levels upper using `parent()` on {}", dir.display())
                 })?
         } else {
             dir.to_owned()
         };

         // On multiarch linux systems, there will be multiarch directory named
         // with the architecture(e.g `x86_64-linux-gnu`) under the `lib` directory.
         // Which cause us to mistakenly end up in the lib directory instead of the sysroot directory.
         if sysroot_dir.ends_with("lib") {
             sysroot_dir =
                 sysroot_dir.parent().map(|real_sysroot| real_sysroot.to_owned()).ok_or_else(
                     || format!("Could not move to parent path of {}", sysroot_dir.display()),
                 )?
         }

         Ok(sysroot_dir)
     }

     // Use env::args().next() to get the path of the executable without
     // following symlinks/canonicalizing any component. This makes the rustc
     // binary able to locate Rust libraries in systems using content-addressable
     // storage (CAS).
     fn from_env_args_next() -> Option<PathBuf> {
         let mut p = PathBuf::from(env::args_os().next()?);

         // Check if sysroot is found using env::args().next() only if the rustc in argv[0]
         // is a symlink (see #79253). We might want to change/remove it to conform with
         // https://www.gnu.org/prep/standards/standards.html#Finding-Program-Files in the
         // future.
         if fs::read_link(&p).is_err() {
             // Path is not a symbolic link or does not exist.
             return None;
         }

         // Pop off `bin/rustc`, obtaining the suspected sysroot.
         p.pop();
         p.pop();
         // Look for the target rustlib directory in the suspected sysroot.
         let mut rustlib_path = rustc_target::relative_target_rustlib_path(&p, "dummy");
         rustlib_path.pop(); // pop off the dummy target.
         rustlib_path.exists().then_some(p)
     }

     from_env_args_next()
         .unwrap_or_else(|| default_from_rustc_driver_dll().expect("Failed finding sysroot"))
 }
	//! A module for searching for libraries

	use std::path::{Path, PathBuf};
	use std::{env, fs};

	use rustc_fs_util::try_canonicalize;
	use rustc_target::spec::Target;

	use crate::search_paths::{PathKind, SearchPath};

	#[derive(Clone)]
	pub struct FileSearch {
	cli_search_paths: Vec<SearchPath>,
	tlib_path: SearchPath,
	}

	impl FileSearch {
	pub fn cli_search_paths<'b>(&'b self, kind: PathKind) -> impl Iterator<Item = &'b SearchPath> {
	self.cli_search_paths.iter().filter(move \|sp\| sp.kind.matches(kind))
	}

	pub fn search_paths<'b>(&'b self, kind: PathKind) -> impl Iterator<Item = &'b SearchPath> {
	self.cli_search_paths
	.iter()
	.filter(move \|sp\| sp.kind.matches(kind))
	.chain(std::iter::once(&self.tlib_path))
	}

	pub fn new(cli_search_paths: &[SearchPath], tlib_path: &SearchPath, target: &Target) -> Self {
	let this = FileSearch {
	cli_search_paths: cli_search_paths.to_owned(),
	tlib_path: tlib_path.clone(),
	};
	this.refine(&["lib", &target.staticlib_prefix, &target.dll_prefix])
	}
	// Produce a new file search from this search that has a smaller set of candidates.
	fn refine(mut self, allowed_prefixes: &[&str]) -> FileSearch {
	self.cli_search_paths
	.iter_mut()
	.for_each(\|search_paths\| search_paths.files.retain(allowed_prefixes));
	self.tlib_path.files.retain(allowed_prefixes);

	self
	}
	}

	pub fn make_target_lib_path(sysroot: &Path, target_triple: &str) -> PathBuf {
	let rustlib_path = rustc_target::relative_target_rustlib_path(sysroot, target_triple);
	sysroot.join(rustlib_path).join("lib")
	}

	/// Returns a path to the target's `bin` folder within its `rustlib` path in the sysroot. This is
	/// where binaries are usually installed, e.g. the self-contained linkers, lld-wrappers, LLVM tools,
	/// etc.
	pub fn make_target_bin_path(sysroot: &Path, target_triple: &str) -> PathBuf {
	let rustlib_path = rustc_target::relative_target_rustlib_path(sysroot, target_triple);
	sysroot.join(rustlib_path).join("bin")
	}

	#[cfg(unix)]
	fn current_dll_path() -> Result<PathBuf, String> {
	use std::sync::OnceLock;

	// This is somewhat expensive relative to other work when compiling `fn main() {}` as `dladdr`
	// needs to iterate over the symbol table of librustc_driver.so until it finds a match.
	// As such cache this to avoid recomputing if we try to get the sysroot in multiple places.
	static CURRENT_DLL_PATH: OnceLock<Result<PathBuf, String>> = OnceLock::new();
	CURRENT_DLL_PATH
	.get_or_init(\|\| {
	use std::ffi::{CStr, OsStr};
	use std::os::unix::prelude::*;

	#[cfg(not(target_os = "aix"))]
	unsafe {
	let addr = current_dll_path as usize as *mut _;
	let mut info = std::mem::zeroed();
	if libc::dladdr(addr, &mut info) == 0 {
	return Err("dladdr failed".into());
	}
	#[cfg(target_os = "cygwin")]
	let fname_ptr = info.dli_fname.as_ptr();
	#[cfg(not(target_os = "cygwin"))]
	let fname_ptr = {
	assert!(!info.dli_fname.is_null(), "dli_fname cannot be null");
	info.dli_fname
	};
	let bytes = CStr::from_ptr(fname_ptr).to_bytes();
	let os = OsStr::from_bytes(bytes);
	try_canonicalize(Path::new(os)).map_err(\|e\| e.to_string())
	}

	#[cfg(target_os = "aix")]
	unsafe {
	// On AIX, the symbol `current_dll_path` references a function descriptor.
	// A function descriptor is consisted of (See https://reviews.llvm.org/D62532)
	// * The address of the entry point of the function.
	// * The TOC base address for the function.
	// * The environment pointer.
	// The function descriptor is in the data section.
	let addr = current_dll_path as u64;
	let mut buffer = vec![std::mem::zeroed::<libc::ld_info>(); 64];
	loop {
	if libc::loadquery(
	libc::L_GETINFO,
	buffer.as_mut_ptr() as *mut u8,
	(size_of::<libc::ld_info>() * buffer.len()) as u32,
	) >= 0
	{
	break;
	} else {
	if std::io::Error::last_os_error().raw_os_error().unwrap() != libc::ENOMEM {
	return Err("loadquery failed".into());
	}
	buffer.resize(buffer.len() * 2, std::mem::zeroed::<libc::ld_info>());
	}
	}
	let mut current = buffer.as_mut_ptr() as *mut libc::ld_info;
	loop {
	let data_base = (*current).ldinfo_dataorg as u64;
	let data_end = data_base + (*current).ldinfo_datasize;
	if (data_base..data_end).contains(&addr) {
	let bytes = CStr::from_ptr(&(*current).ldinfo_filename[0]).to_bytes();
	let os = OsStr::from_bytes(bytes);
	return try_canonicalize(Path::new(os)).map_err(\|e\| e.to_string());
	}
	if (*current).ldinfo_next == 0 {
	break;
	}
	current = (current as mut i8).offset((current).ldinfo_next as isize)
	as *mut libc::ld_info;
	}
	return Err(format!("current dll's address {} is not in the load map", addr));
	}
	})
	.clone()
	}

	#[cfg(windows)]
	fn current_dll_path() -> Result<PathBuf, String> {
	use std::ffi::OsString;
	use std::io;
	use std::os::windows::prelude::*;

	use windows::Win32::Foundation::HMODULE;
	use windows::Win32::System::LibraryLoader::{
	GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS, GetModuleFileNameW, GetModuleHandleExW,
	};
	use windows::core::PCWSTR;

	let mut module = HMODULE::default();
	unsafe {
	GetModuleHandleExW(
	GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
	PCWSTR(current_dll_path as *mut u16),
	&mut module,
	)
	}
	.map_err(\|e\| e.to_string())?;

	let mut filename = vec![0; 1024];
	let n = unsafe { GetModuleFileNameW(Some(module), &mut filename) } as usize;
	if n == 0 {
	return Err(format!("GetModuleFileNameW failed: {}", io::Error::last_os_error()));
	}
	if n >= filename.capacity() {
	return Err(format!("our buffer was too small? {}", io::Error::last_os_error()));
	}

	filename.truncate(n);

	let path = try_canonicalize(OsString::from_wide(&filename)).map_err(\|e\| e.to_string())?;

	// See comments on this target function, but the gist is that
	// gcc chokes on verbatim paths which fs::canonicalize generates
	// so we try to avoid those kinds of paths.
	Ok(rustc_fs_util::fix_windows_verbatim_for_gcc(&path))
	}

	#[cfg(target_os = "wasi")]
	fn current_dll_path() -> Result<PathBuf, String> {
	Err("current_dll_path is not supported on WASI".to_string())
	}

	/// This function checks if sysroot is found using env::args().next(), and if it
	/// is not found, finds sysroot from current rustc_driver dll.
	pub(crate) fn default_sysroot() -> PathBuf {
	fn default_from_rustc_driver_dll() -> Result<PathBuf, String> {
	let dll = current_dll_path()?;

	// `dll` will be in one of the following two:
	// - compiler's libdir: $sysroot/lib/*.dll
	// - target's libdir: $sysroot/lib/rustlib/$target/lib/*.dll
	//
	// use `parent` twice to chop off the file name and then also the
	// directory containing the dll
	let dir = dll.parent().and_then(\|p\| p.parent()).ok_or_else(\|\| {
	format!("Could not move 2 levels upper using `parent()` on {}", dll.display())
	})?;

	// if `dir` points to target's dir, move up to the sysroot
	let mut sysroot_dir = if dir.ends_with(crate::config::host_tuple()) {
	dir.parent() // chop off `$target`
	.and_then(\|p\| p.parent()) // chop off `rustlib`
	.and_then(\|p\| p.parent()) // chop off `lib`
	.map(\|s\| s.to_owned())
	.ok_or_else(\|\| {
	format!("Could not move 3 levels upper using `parent()` on {}", dir.display())
	})?
	} else {
	dir.to_owned()
	};

	// On multiarch linux systems, there will be multiarch directory named
	// with the architecture(e.g `x86_64-linux-gnu`) under the `lib` directory.
	// Which cause us to mistakenly end up in the lib directory instead of the sysroot directory.
	if sysroot_dir.ends_with("lib") {
	sysroot_dir =
	sysroot_dir.parent().map(\|real_sysroot\| real_sysroot.to_owned()).ok_or_else(
	\|\| format!("Could not move to parent path of {}", sysroot_dir.display()),
	)?
	}

	Ok(sysroot_dir)
	}

	// Use env::args().next() to get the path of the executable without
	// following symlinks/canonicalizing any component. This makes the rustc
	// binary able to locate Rust libraries in systems using content-addressable
	// storage (CAS).
	fn from_env_args_next() -> Option<PathBuf> {
	let mut p = PathBuf::from(env::args_os().next()?);

	// Check if sysroot is found using env::args().next() only if the rustc in argv[0]
	// is a symlink (see #79253). We might want to change/remove it to conform with
	// https://www.gnu.org/prep/standards/standards.html#Finding-Program-Files in the
	// future.
	if fs::read_link(&p).is_err() {
	// Path is not a symbolic link or does not exist.
	return None;
	}

	// Pop off `bin/rustc`, obtaining the suspected sysroot.
	p.pop();
	p.pop();
	// Look for the target rustlib directory in the suspected sysroot.
	let mut rustlib_path = rustc_target::relative_target_rustlib_path(&p, "dummy");
	rustlib_path.pop(); // pop off the dummy target.
	rustlib_path.exists().then_some(p)
	}

	from_env_args_next()
	.unwrap_or_else(\|\| default_from_rustc_driver_dll().expect("Failed finding sysroot"))
	}