src/tools/miri/src/shims/unix/env.rs - third_party/rust - Git at Google

 use std::env;
 use std::ffi::{OsStr, OsString};
 use std::io::ErrorKind;
 use std::mem;

 use rustc_data_structures::fx::FxHashMap;
 use rustc_middle::ty::layout::LayoutOf;
 use rustc_middle::ty::Ty;
 use rustc_target::abi::Size;

 use crate::*;

 pub struct UnixEnvVars<'tcx> {
     /// Stores pointers to the environment variables. These variables must be stored as
     /// null-terminated target strings (c_str or wide_str) with the `"{name}={value}"` format.
     map: FxHashMap<OsString, Pointer>,

     /// Place where the `environ` static is stored. Lazily initialized, but then never changes.
     environ: MPlaceTy<'tcx>,
 }

 impl VisitProvenance for UnixEnvVars<'_> {
     fn visit_provenance(&self, visit: &mut VisitWith<'_>) {
         let UnixEnvVars { map, environ } = self;

         environ.visit_provenance(visit);
         for ptr in map.values() {
             ptr.visit_provenance(visit);
         }
     }
 }

 impl<'tcx> UnixEnvVars<'tcx> {
     pub(crate) fn new(
         ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
         env_vars: FxHashMap<OsString, OsString>,
     ) -> InterpResult<'tcx, Self> {
         // Allocate memory for all these env vars.
         let mut env_vars_machine = FxHashMap::default();
         for (name, val) in env_vars.into_iter() {
             let ptr = alloc_env_var(ecx, &name, &val)?;
             env_vars_machine.insert(name, ptr);
         }

         // This is memory backing an extern static, hence `ExternStatic`, not `Env`.
         let layout = ecx.machine.layouts.mut_raw_ptr;
         let environ = ecx.allocate(layout, MiriMemoryKind::ExternStatic.into())?;
         let environ_block = alloc_environ_block(ecx, env_vars_machine.values().copied().collect())?;
         ecx.write_pointer(environ_block, &environ)?;

         Ok(UnixEnvVars { map: env_vars_machine, environ })
     }

     pub(crate) fn cleanup(ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>) -> InterpResult<'tcx> {
         // Deallocate individual env vars.
         let env_vars = mem::take(&mut ecx.machine.env_vars.unix_mut().map);
         for (_name, ptr) in env_vars {
             ecx.deallocate_ptr(ptr, None, MiriMemoryKind::Runtime.into())?;
         }
         // Deallocate environ var list.
         let environ = &ecx.machine.env_vars.unix().environ;
         let old_vars_ptr = ecx.read_pointer(environ)?;
         ecx.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;

         Ok(())
     }

     pub(crate) fn environ(&self) -> Pointer {
         self.environ.ptr()
     }

     fn get_ptr(
         &self,
         ecx: &InterpCx<'tcx, MiriMachine<'tcx>>,
         name: &OsStr,
     ) -> InterpResult<'tcx, Option<Pointer>> {
         // We don't care about the value as we have the `map` to keep track of everything,
         // but we do want to do this read so it shows up as a data race.
         let _vars_ptr = ecx.read_pointer(&self.environ)?;
         let Some(var_ptr) = self.map.get(name) else {
             return Ok(None);
         };
         // The offset is used to strip the "{name}=" part of the string.
         let var_ptr = var_ptr
             .offset(Size::from_bytes(u64::try_from(name.len()).unwrap().strict_add(1)), ecx)?;
         Ok(Some(var_ptr))
     }

     /// Implementation detail for [`InterpCx::get_env_var`]. This basically does `getenv`, complete
     /// with the reads of the environment, but returns an [`OsString`] instead of a pointer.
     pub(crate) fn get(
         &self,
         ecx: &InterpCx<'tcx, MiriMachine<'tcx>>,
         name: &OsStr,
     ) -> InterpResult<'tcx, Option<OsString>> {
         let var_ptr = self.get_ptr(ecx, name)?;
         if let Some(ptr) = var_ptr {
             let var = ecx.read_os_str_from_c_str(ptr)?;
             Ok(Some(var.to_owned()))
         } else {
             Ok(None)
         }
     }
 }

 fn alloc_env_var<'tcx>(
     ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
     name: &OsStr,
     value: &OsStr,
 ) -> InterpResult<'tcx, Pointer> {
     let mut name_osstring = name.to_os_string();
     name_osstring.push("=");
     name_osstring.push(value);
     ecx.alloc_os_str_as_c_str(name_osstring.as_os_str(), MiriMemoryKind::Runtime.into())
 }

 /// Allocates an `environ` block with the given list of pointers.
 fn alloc_environ_block<'tcx>(
     ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
     mut vars: Vec<Pointer>,
 ) -> InterpResult<'tcx, Pointer> {
     // Add trailing null.
     vars.push(Pointer::null());
     // Make an array with all these pointers inside Miri.
     let vars_layout = ecx.layout_of(Ty::new_array(
         *ecx.tcx,
         ecx.machine.layouts.mut_raw_ptr.ty,
         u64::try_from(vars.len()).unwrap(),
     ))?;
     let vars_place = ecx.allocate(vars_layout, MiriMemoryKind::Runtime.into())?;
     for (idx, var) in vars.into_iter().enumerate() {
         let place = ecx.project_field(&vars_place, idx)?;
         ecx.write_pointer(var, &place)?;
     }
     Ok(vars_place.ptr())
 }

 impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
 pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
     fn getenv(&mut self, name_op: &OpTy<'tcx>) -> InterpResult<'tcx, Pointer> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("getenv");

         let name_ptr = this.read_pointer(name_op)?;
         let name = this.read_os_str_from_c_str(name_ptr)?;

         let var_ptr = this.machine.env_vars.unix().get_ptr(this, name)?;
         Ok(var_ptr.unwrap_or_else(Pointer::null))
     }

     fn setenv(&mut self, name_op: &OpTy<'tcx>, value_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("setenv");

         let name_ptr = this.read_pointer(name_op)?;
         let value_ptr = this.read_pointer(value_op)?;

         let mut new = None;
         if !this.ptr_is_null(name_ptr)? {
             let name = this.read_os_str_from_c_str(name_ptr)?;
             if !name.is_empty() && !name.to_string_lossy().contains('=') {
                 let value = this.read_os_str_from_c_str(value_ptr)?;
                 new = Some((name.to_owned(), value.to_owned()));
             }
         }
         if let Some((name, value)) = new {
             let var_ptr = alloc_env_var(this, &name, &value)?;
             if let Some(var) = this.machine.env_vars.unix_mut().map.insert(name, var_ptr) {
                 this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
             }
             this.update_environ()?;
             Ok(0) // return zero on success
         } else {
             // name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
             let einval = this.eval_libc("EINVAL");
             this.set_last_error(einval)?;
             Ok(-1)
         }
     }

     fn unsetenv(&mut self, name_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("unsetenv");

         let name_ptr = this.read_pointer(name_op)?;
         let mut success = None;
         if !this.ptr_is_null(name_ptr)? {
             let name = this.read_os_str_from_c_str(name_ptr)?.to_owned();
             if !name.is_empty() && !name.to_string_lossy().contains('=') {
                 success = Some(this.machine.env_vars.unix_mut().map.remove(&name));
             }
         }
         if let Some(old) = success {
             if let Some(var) = old {
                 this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
             }
             this.update_environ()?;
             Ok(0)
         } else {
             // name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
             let einval = this.eval_libc("EINVAL");
             this.set_last_error(einval)?;
             Ok(-1)
         }
     }

     fn getcwd(&mut self, buf_op: &OpTy<'tcx>, size_op: &OpTy<'tcx>) -> InterpResult<'tcx, Pointer> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("getcwd");

         let buf = this.read_pointer(buf_op)?;
         let size = this.read_target_usize(size_op)?;

         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
             this.reject_in_isolation("`getcwd`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied.into())?;
             return Ok(Pointer::null());
         }

         // If we cannot get the current directory, we return null
         match env::current_dir() {
             Ok(cwd) => {
                 if this.write_path_to_c_str(&cwd, buf, size)?.0 {
                     return Ok(buf);
                 }
                 let erange = this.eval_libc("ERANGE");
                 this.set_last_error(erange)?;
             }
             Err(e) => this.set_last_error_from_io_error(e)?,
         }

         Ok(Pointer::null())
     }

     fn chdir(&mut self, path_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("chdir");

         let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;

         if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
             this.reject_in_isolation("`chdir`", reject_with)?;
             this.set_last_error_from_io_error(ErrorKind::PermissionDenied.into())?;

             return Ok(-1);
         }

         match env::set_current_dir(path) {
             Ok(()) => Ok(0),
             Err(e) => {
                 this.set_last_error_from_io_error(e)?;
                 Ok(-1)
             }
         }
     }

     /// Updates the `environ` static.
     fn update_environ(&mut self) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
         // Deallocate the old environ list.
         let environ = this.machine.env_vars.unix().environ.clone();
         let old_vars_ptr = this.read_pointer(&environ)?;
         this.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;

         // Write the new list.
         let vals = this.machine.env_vars.unix().map.values().copied().collect();
         let environ_block = alloc_environ_block(this, vals)?;
         this.write_pointer(environ_block, &environ)?;

         Ok(())
     }

     fn getpid(&mut self) -> InterpResult<'tcx, i32> {
         let this = self.eval_context_mut();
         this.assert_target_os_is_unix("getpid");

         this.check_no_isolation("`getpid`")?;

         // The reason we need to do this wacky of a conversion is because
         // `libc::getpid` returns an i32, however, `std::process::id()` return an u32.
         // So we un-do the conversion that stdlib does and turn it back into an i32.
         #[allow(clippy::cast_possible_wrap)]
         Ok(std::process::id() as i32)
     }
 }
	use std::env;
	use std::ffi::{OsStr, OsString};
	use std::io::ErrorKind;
	use std::mem;

	use rustc_data_structures::fx::FxHashMap;
	use rustc_middle::ty::layout::LayoutOf;
	use rustc_middle::ty::Ty;
	use rustc_target::abi::Size;

	use crate::*;

	pub struct UnixEnvVars<'tcx> {
	/// Stores pointers to the environment variables. These variables must be stored as
	/// null-terminated target strings (c_str or wide_str) with the `"{name}={value}"` format.
	map: FxHashMap<OsString, Pointer>,

	/// Place where the `environ` static is stored. Lazily initialized, but then never changes.
	environ: MPlaceTy<'tcx>,
	}

	impl VisitProvenance for UnixEnvVars<'_> {
	fn visit_provenance(&self, visit: &mut VisitWith<'_>) {
	let UnixEnvVars { map, environ } = self;

	environ.visit_provenance(visit);
	for ptr in map.values() {
	ptr.visit_provenance(visit);
	}
	}
	}

	impl<'tcx> UnixEnvVars<'tcx> {
	pub(crate) fn new(
	ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
	env_vars: FxHashMap<OsString, OsString>,
	) -> InterpResult<'tcx, Self> {
	// Allocate memory for all these env vars.
	let mut env_vars_machine = FxHashMap::default();
	for (name, val) in env_vars.into_iter() {
	let ptr = alloc_env_var(ecx, &name, &val)?;
	env_vars_machine.insert(name, ptr);
	}

	// This is memory backing an extern static, hence `ExternStatic`, not `Env`.
	let layout = ecx.machine.layouts.mut_raw_ptr;
	let environ = ecx.allocate(layout, MiriMemoryKind::ExternStatic.into())?;
	let environ_block = alloc_environ_block(ecx, env_vars_machine.values().copied().collect())?;
	ecx.write_pointer(environ_block, &environ)?;

	Ok(UnixEnvVars { map: env_vars_machine, environ })
	}

	pub(crate) fn cleanup(ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>) -> InterpResult<'tcx> {
	// Deallocate individual env vars.
	let env_vars = mem::take(&mut ecx.machine.env_vars.unix_mut().map);
	for (_name, ptr) in env_vars {
	ecx.deallocate_ptr(ptr, None, MiriMemoryKind::Runtime.into())?;
	}
	// Deallocate environ var list.
	let environ = &ecx.machine.env_vars.unix().environ;
	let old_vars_ptr = ecx.read_pointer(environ)?;
	ecx.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;

	Ok(())
	}

	pub(crate) fn environ(&self) -> Pointer {
	self.environ.ptr()
	}

	fn get_ptr(
	&self,
	ecx: &InterpCx<'tcx, MiriMachine<'tcx>>,
	name: &OsStr,
	) -> InterpResult<'tcx, Option<Pointer>> {
	// We don't care about the value as we have the `map` to keep track of everything,
	// but we do want to do this read so it shows up as a data race.
	let _vars_ptr = ecx.read_pointer(&self.environ)?;
	let Some(var_ptr) = self.map.get(name) else {
	return Ok(None);
	};
	// The offset is used to strip the "{name}=" part of the string.
	let var_ptr = var_ptr
	.offset(Size::from_bytes(u64::try_from(name.len()).unwrap().strict_add(1)), ecx)?;
	Ok(Some(var_ptr))
	}

	/// Implementation detail for [`InterpCx::get_env_var`]. This basically does `getenv`, complete
	/// with the reads of the environment, but returns an [`OsString`] instead of a pointer.
	pub(crate) fn get(
	&self,
	ecx: &InterpCx<'tcx, MiriMachine<'tcx>>,
	name: &OsStr,
	) -> InterpResult<'tcx, Option<OsString>> {
	let var_ptr = self.get_ptr(ecx, name)?;
	if let Some(ptr) = var_ptr {
	let var = ecx.read_os_str_from_c_str(ptr)?;
	Ok(Some(var.to_owned()))
	} else {
	Ok(None)
	}
	}
	}

	fn alloc_env_var<'tcx>(
	ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
	name: &OsStr,
	value: &OsStr,
	) -> InterpResult<'tcx, Pointer> {
	let mut name_osstring = name.to_os_string();
	name_osstring.push("=");
	name_osstring.push(value);
	ecx.alloc_os_str_as_c_str(name_osstring.as_os_str(), MiriMemoryKind::Runtime.into())
	}

	/// Allocates an `environ` block with the given list of pointers.
	fn alloc_environ_block<'tcx>(
	ecx: &mut InterpCx<'tcx, MiriMachine<'tcx>>,
	mut vars: Vec<Pointer>,
	) -> InterpResult<'tcx, Pointer> {
	// Add trailing null.
	vars.push(Pointer::null());
	// Make an array with all these pointers inside Miri.
	let vars_layout = ecx.layout_of(Ty::new_array(
	*ecx.tcx,
	ecx.machine.layouts.mut_raw_ptr.ty,
	u64::try_from(vars.len()).unwrap(),
	))?;
	let vars_place = ecx.allocate(vars_layout, MiriMemoryKind::Runtime.into())?;
	for (idx, var) in vars.into_iter().enumerate() {
	let place = ecx.project_field(&vars_place, idx)?;
	ecx.write_pointer(var, &place)?;
	}
	Ok(vars_place.ptr())
	}

	impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
	pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
	fn getenv(&mut self, name_op: &OpTy<'tcx>) -> InterpResult<'tcx, Pointer> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("getenv");

	let name_ptr = this.read_pointer(name_op)?;
	let name = this.read_os_str_from_c_str(name_ptr)?;

	let var_ptr = this.machine.env_vars.unix().get_ptr(this, name)?;
	Ok(var_ptr.unwrap_or_else(Pointer::null))
	}

	fn setenv(&mut self, name_op: &OpTy<'tcx>, value_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("setenv");

	let name_ptr = this.read_pointer(name_op)?;
	let value_ptr = this.read_pointer(value_op)?;

	let mut new = None;
	if !this.ptr_is_null(name_ptr)? {
	let name = this.read_os_str_from_c_str(name_ptr)?;
	if !name.is_empty() && !name.to_string_lossy().contains('=') {
	let value = this.read_os_str_from_c_str(value_ptr)?;
	new = Some((name.to_owned(), value.to_owned()));
	}
	}
	if let Some((name, value)) = new {
	let var_ptr = alloc_env_var(this, &name, &value)?;
	if let Some(var) = this.machine.env_vars.unix_mut().map.insert(name, var_ptr) {
	this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
	}
	this.update_environ()?;
	Ok(0) // return zero on success
	} else {
	// name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
	let einval = this.eval_libc("EINVAL");
	this.set_last_error(einval)?;
	Ok(-1)
	}
	}

	fn unsetenv(&mut self, name_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("unsetenv");

	let name_ptr = this.read_pointer(name_op)?;
	let mut success = None;
	if !this.ptr_is_null(name_ptr)? {
	let name = this.read_os_str_from_c_str(name_ptr)?.to_owned();
	if !name.is_empty() && !name.to_string_lossy().contains('=') {
	success = Some(this.machine.env_vars.unix_mut().map.remove(&name));
	}
	}
	if let Some(old) = success {
	if let Some(var) = old {
	this.deallocate_ptr(var, None, MiriMemoryKind::Runtime.into())?;
	}
	this.update_environ()?;
	Ok(0)
	} else {
	// name argument is a null pointer, points to an empty string, or points to a string containing an '=' character.
	let einval = this.eval_libc("EINVAL");
	this.set_last_error(einval)?;
	Ok(-1)
	}
	}

	fn getcwd(&mut self, buf_op: &OpTy<'tcx>, size_op: &OpTy<'tcx>) -> InterpResult<'tcx, Pointer> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("getcwd");

	let buf = this.read_pointer(buf_op)?;
	let size = this.read_target_usize(size_op)?;

	if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
	this.reject_in_isolation("`getcwd`", reject_with)?;
	this.set_last_error_from_io_error(ErrorKind::PermissionDenied.into())?;
	return Ok(Pointer::null());
	}

	// If we cannot get the current directory, we return null
	match env::current_dir() {
	Ok(cwd) => {
	if this.write_path_to_c_str(&cwd, buf, size)?.0 {
	return Ok(buf);
	}
	let erange = this.eval_libc("ERANGE");
	this.set_last_error(erange)?;
	}
	Err(e) => this.set_last_error_from_io_error(e)?,
	}

	Ok(Pointer::null())
	}

	fn chdir(&mut self, path_op: &OpTy<'tcx>) -> InterpResult<'tcx, i32> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("chdir");

	let path = this.read_path_from_c_str(this.read_pointer(path_op)?)?;

	if let IsolatedOp::Reject(reject_with) = this.machine.isolated_op {
	this.reject_in_isolation("`chdir`", reject_with)?;
	this.set_last_error_from_io_error(ErrorKind::PermissionDenied.into())?;

	return Ok(-1);
	}

	match env::set_current_dir(path) {
	Ok(()) => Ok(0),
	Err(e) => {
	this.set_last_error_from_io_error(e)?;
	Ok(-1)
	}
	}
	}

	/// Updates the `environ` static.
	fn update_environ(&mut self) -> InterpResult<'tcx> {
	let this = self.eval_context_mut();
	// Deallocate the old environ list.
	let environ = this.machine.env_vars.unix().environ.clone();
	let old_vars_ptr = this.read_pointer(&environ)?;
	this.deallocate_ptr(old_vars_ptr, None, MiriMemoryKind::Runtime.into())?;

	// Write the new list.
	let vals = this.machine.env_vars.unix().map.values().copied().collect();
	let environ_block = alloc_environ_block(this, vals)?;
	this.write_pointer(environ_block, &environ)?;

	Ok(())
	}

	fn getpid(&mut self) -> InterpResult<'tcx, i32> {
	let this = self.eval_context_mut();
	this.assert_target_os_is_unix("getpid");

	this.check_no_isolation("`getpid`")?;

	// The reason we need to do this wacky of a conversion is because
	// `libc::getpid` returns an i32, however, `std::process::id()` return an u32.
	// So we un-do the conversion that stdlib does and turn it back into an i32.
	#[allow(clippy::cast_possible_wrap)]
	Ok(std::process::id() as i32)
	}
	}