src/tools/miri/src/shims/unix/linux/foreign_items.rs - toolchain/rustc - Git at Google

 use rustc_span::Symbol;
 use rustc_target::spec::abi::Abi;

 use crate::machine::SIGRTMAX;
 use crate::machine::SIGRTMIN;
 use crate::*;
 use shims::foreign_items::EmulateByNameResult;
 use shims::unix::fs::EvalContextExt as _;
 use shims::unix::linux::fd::EvalContextExt as _;
 use shims::unix::linux::mem::EvalContextExt as _;
 use shims::unix::linux::sync::futex;
 use shims::unix::sync::EvalContextExt as _;
 use shims::unix::thread::EvalContextExt as _;

 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
     fn emulate_foreign_item_by_name(
         &mut self,
         link_name: Symbol,
         abi: Abi,
         args: &[OpTy<'tcx, Provenance>],
         dest: &PlaceTy<'tcx, Provenance>,
     ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
         let this = self.eval_context_mut();

         // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.

         match link_name.as_str() {
             // errno
             "__errno_location" => {
                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let errno_place = this.last_error_place()?;
                 this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
             }

             // File related shims (but also see "syscall" below for statx)
             "readdir64" => {
                 let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.linux_readdir64(dirp)?;
                 this.write_scalar(result, dest)?;
             }
             // Linux-only
             "sync_file_range" => {
                 let [fd, offset, nbytes, flags] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.sync_file_range(fd, offset, nbytes, flags)?;
                 this.write_scalar(result, dest)?;
             }
             "epoll_create1" => {
                 let [flag] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.epoll_create1(flag)?;
                 this.write_scalar(result, dest)?;
             }
             "epoll_ctl" => {
                 let [epfd, op, fd, event] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.epoll_ctl(epfd, op, fd, event)?;
                 this.write_scalar(result, dest)?;
             }
             "epoll_wait" => {
                 let [epfd, events, maxevents, timeout] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.epoll_wait(epfd, events, maxevents, timeout)?;
                 this.write_scalar(result, dest)?;
             }
             "eventfd" => {
                 let [val, flag] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.eventfd(val, flag)?;
                 this.write_scalar(result, dest)?;
             }
             "mremap" => {
                 let [old_address, old_size, new_size, flags] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let ptr = this.mremap(old_address, old_size, new_size, flags)?;
                 this.write_scalar(ptr, dest)?;
             }
             "socketpair" => {
                 let [domain, type_, protocol, sv] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

                 let result = this.socketpair(domain, type_, protocol, sv)?;
                 this.write_scalar(result, dest)?;
             }
             "__libc_current_sigrtmin" => {
                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

                 this.write_scalar(Scalar::from_i32(SIGRTMIN), dest)?;
             }
             "__libc_current_sigrtmax" => {
                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

                 this.write_scalar(Scalar::from_i32(SIGRTMAX), dest)?;
             }

             // Threading
             "pthread_condattr_setclock" => {
                 let [attr, clock_id] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.pthread_condattr_setclock(attr, clock_id)?;
                 this.write_scalar(result, dest)?;
             }
             "pthread_condattr_getclock" => {
                 let [attr, clock_id] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let result = this.pthread_condattr_getclock(attr, clock_id)?;
                 this.write_scalar(result, dest)?;
             }
             "pthread_setname_np" => {
                 let [thread, name] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let max_len = 16;
                 let res = this.pthread_setname_np(
                     this.read_scalar(thread)?,
                     this.read_scalar(name)?,
                     max_len,
                 )?;
                 this.write_scalar(res, dest)?;
             }
             "pthread_getname_np" => {
                 let [thread, name, len] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 let res = this.pthread_getname_np(
                     this.read_scalar(thread)?,
                     this.read_scalar(name)?,
                     this.read_scalar(len)?,
                 )?;
                 this.write_scalar(res, dest)?;
             }

             // Dynamically invoked syscalls
             "syscall" => {
                 // We do not use `check_shim` here because `syscall` is variadic. The argument
                 // count is checked bellow.
                 this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
                 // The syscall variadic function is legal to call with more arguments than needed,
                 // extra arguments are simply ignored. The important check is that when we use an
                 // argument, we have to also check all arguments *before* it to ensure that they
                 // have the right type.

                 let sys_getrandom = this.eval_libc("SYS_getrandom").to_target_usize(this)?;

                 let sys_statx = this.eval_libc("SYS_statx").to_target_usize(this)?;

                 let sys_futex = this.eval_libc("SYS_futex").to_target_usize(this)?;

                 if args.is_empty() {
                     throw_ub_format!(
                         "incorrect number of arguments for syscall: got 0, expected at least 1"
                     );
                 }
                 match this.read_target_usize(&args[0])? {
                     // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
                     // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
                     id if id == sys_getrandom => {
                         // The first argument is the syscall id, so skip over it.
                         if args.len() < 4 {
                             throw_ub_format!(
                                 "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
                                 args.len()
                             );
                         }
                         getrandom(this, &args[1], &args[2], &args[3], dest)?;
                     }
                     // `statx` is used by `libstd` to retrieve metadata information on `linux`
                     // instead of using `stat`,`lstat` or `fstat` as on `macos`.
                     id if id == sys_statx => {
                         // The first argument is the syscall id, so skip over it.
                         if args.len() < 6 {
                             throw_ub_format!(
                                 "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
                                 args.len()
                             );
                         }
                         let result =
                             this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
                         this.write_scalar(Scalar::from_target_isize(result.into(), this), dest)?;
                     }
                     // `futex` is used by some synchronization primitives.
                     id if id == sys_futex => {
                         futex(this, &args[1..], dest)?;
                     }
                     id => {
                         this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
                         return Ok(EmulateByNameResult::AlreadyJumped);
                     }
                 }
             }

             // Miscellaneous
             "getrandom" => {
                 let [ptr, len, flags] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 getrandom(this, ptr, len, flags, dest)?;
             }
             "sched_getaffinity" => {
                 let [pid, cpusetsize, mask] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 this.read_scalar(pid)?.to_i32()?;
                 this.read_target_usize(cpusetsize)?;
                 this.deref_pointer_as(mask, this.libc_ty_layout("cpu_set_t"))?;
                 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
                 let einval = this.eval_libc("EINVAL");
                 this.set_last_error(einval)?;
                 this.write_scalar(Scalar::from_i32(-1), dest)?;
             }

             // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
             // These shims are enabled only when the caller is in the standard library.
             "pthread_getattr_np" if this.frame_in_std() => {
                 let [_thread, _attr] =
                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
                 this.write_null(dest)?;
             }

             _ => return Ok(EmulateByNameResult::NotSupported),
         };

         Ok(EmulateByNameResult::NeedsJumping)
     }
 }

 // Shims the linux `getrandom` syscall.
 fn getrandom<'tcx>(
     this: &mut MiriInterpCx<'_, 'tcx>,
     ptr: &OpTy<'tcx, Provenance>,
     len: &OpTy<'tcx, Provenance>,
     flags: &OpTy<'tcx, Provenance>,
     dest: &PlaceTy<'tcx, Provenance>,
 ) -> InterpResult<'tcx> {
     let ptr = this.read_pointer(ptr)?;
     let len = this.read_target_usize(len)?;

     // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
     // neither of which have any effect on our current PRNG.
     // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
     let _flags = this.read_scalar(flags)?.to_i32();

     this.gen_random(ptr, len)?;
     this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
     Ok(())
 }
	use rustc_span::Symbol;
	use rustc_target::spec::abi::Abi;

	use crate::machine::SIGRTMAX;
	use crate::machine::SIGRTMIN;
	use crate::*;
	use shims::foreign_items::EmulateByNameResult;
	use shims::unix::fs::EvalContextExt as _;
	use shims::unix::linux::fd::EvalContextExt as _;
	use shims::unix::linux::mem::EvalContextExt as _;
	use shims::unix::linux::sync::futex;
	use shims::unix::sync::EvalContextExt as _;
	use shims::unix::thread::EvalContextExt as _;

	impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
	pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
	fn emulate_foreign_item_by_name(
	&mut self,
	link_name: Symbol,
	abi: Abi,
	args: &[OpTy<'tcx, Provenance>],
	dest: &PlaceTy<'tcx, Provenance>,
	) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
	let this = self.eval_context_mut();

	// See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.

	match link_name.as_str() {
	// errno
	"__errno_location" => {
	let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let errno_place = this.last_error_place()?;
	this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
	}

	// File related shims (but also see "syscall" below for statx)
	"readdir64" => {
	let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.linux_readdir64(dirp)?;
	this.write_scalar(result, dest)?;
	}
	// Linux-only
	"sync_file_range" => {
	let [fd, offset, nbytes, flags] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.sync_file_range(fd, offset, nbytes, flags)?;
	this.write_scalar(result, dest)?;
	}
	"epoll_create1" => {
	let [flag] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.epoll_create1(flag)?;
	this.write_scalar(result, dest)?;
	}
	"epoll_ctl" => {
	let [epfd, op, fd, event] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.epoll_ctl(epfd, op, fd, event)?;
	this.write_scalar(result, dest)?;
	}
	"epoll_wait" => {
	let [epfd, events, maxevents, timeout] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.epoll_wait(epfd, events, maxevents, timeout)?;
	this.write_scalar(result, dest)?;
	}
	"eventfd" => {
	let [val, flag] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.eventfd(val, flag)?;
	this.write_scalar(result, dest)?;
	}
	"mremap" => {
	let [old_address, old_size, new_size, flags] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let ptr = this.mremap(old_address, old_size, new_size, flags)?;
	this.write_scalar(ptr, dest)?;
	}
	"socketpair" => {
	let [domain, type_, protocol, sv] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

	let result = this.socketpair(domain, type_, protocol, sv)?;
	this.write_scalar(result, dest)?;
	}
	"__libc_current_sigrtmin" => {
	let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

	this.write_scalar(Scalar::from_i32(SIGRTMIN), dest)?;
	}
	"__libc_current_sigrtmax" => {
	let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;

	this.write_scalar(Scalar::from_i32(SIGRTMAX), dest)?;
	}

	// Threading
	"pthread_condattr_setclock" => {
	let [attr, clock_id] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.pthread_condattr_setclock(attr, clock_id)?;
	this.write_scalar(result, dest)?;
	}
	"pthread_condattr_getclock" => {
	let [attr, clock_id] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let result = this.pthread_condattr_getclock(attr, clock_id)?;
	this.write_scalar(result, dest)?;
	}
	"pthread_setname_np" => {
	let [thread, name] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let max_len = 16;
	let res = this.pthread_setname_np(
	this.read_scalar(thread)?,
	this.read_scalar(name)?,
	max_len,
	)?;
	this.write_scalar(res, dest)?;
	}
	"pthread_getname_np" => {
	let [thread, name, len] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	let res = this.pthread_getname_np(
	this.read_scalar(thread)?,
	this.read_scalar(name)?,
	this.read_scalar(len)?,
	)?;
	this.write_scalar(res, dest)?;
	}

	// Dynamically invoked syscalls
	"syscall" => {
	// We do not use `check_shim` here because `syscall` is variadic. The argument
	// count is checked bellow.
	this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
	// The syscall variadic function is legal to call with more arguments than needed,
	// extra arguments are simply ignored. The important check is that when we use an
	// argument, we have to also check all arguments before it to ensure that they
	// have the right type.

	let sys_getrandom = this.eval_libc("SYS_getrandom").to_target_usize(this)?;

	let sys_statx = this.eval_libc("SYS_statx").to_target_usize(this)?;

	let sys_futex = this.eval_libc("SYS_futex").to_target_usize(this)?;

	if args.is_empty() {
	throw_ub_format!(
	"incorrect number of arguments for syscall: got 0, expected at least 1"
	);
	}
	match this.read_target_usize(&args[0])? {
	// `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
	// is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
	id if id == sys_getrandom => {
	// The first argument is the syscall id, so skip over it.
	if args.len() < 4 {
	throw_ub_format!(
	"incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
	args.len()
	);
	}
	getrandom(this, &args[1], &args[2], &args[3], dest)?;
	}
	// `statx` is used by `libstd` to retrieve metadata information on `linux`
	// instead of using `stat`,`lstat` or `fstat` as on `macos`.
	id if id == sys_statx => {
	// The first argument is the syscall id, so skip over it.
	if args.len() < 6 {
	throw_ub_format!(
	"incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
	args.len()
	);
	}
	let result =
	this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
	this.write_scalar(Scalar::from_target_isize(result.into(), this), dest)?;
	}
	// `futex` is used by some synchronization primitives.
	id if id == sys_futex => {
	futex(this, &args[1..], dest)?;
	}
	id => {
	this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
	return Ok(EmulateByNameResult::AlreadyJumped);
	}
	}
	}

	// Miscellaneous
	"getrandom" => {
	let [ptr, len, flags] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	getrandom(this, ptr, len, flags, dest)?;
	}
	"sched_getaffinity" => {
	let [pid, cpusetsize, mask] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	this.read_scalar(pid)?.to_i32()?;
	this.read_target_usize(cpusetsize)?;
	this.deref_pointer_as(mask, this.libc_ty_layout("cpu_set_t"))?;
	// FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
	let einval = this.eval_libc("EINVAL");
	this.set_last_error(einval)?;
	this.write_scalar(Scalar::from_i32(-1), dest)?;
	}

	// Incomplete shims that we "stub out" just to get pre-main initialization code to work.
	// These shims are enabled only when the caller is in the standard library.
	"pthread_getattr_np" if this.frame_in_std() => {
	let [_thread, _attr] =
	this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
	this.write_null(dest)?;
	}

	_ => return Ok(EmulateByNameResult::NotSupported),
	};

	Ok(EmulateByNameResult::NeedsJumping)
	}
	}

	// Shims the linux `getrandom` syscall.
	fn getrandom<'tcx>(
	this: &mut MiriInterpCx<'_, 'tcx>,
	ptr: &OpTy<'tcx, Provenance>,
	len: &OpTy<'tcx, Provenance>,
	flags: &OpTy<'tcx, Provenance>,
	dest: &PlaceTy<'tcx, Provenance>,
	) -> InterpResult<'tcx> {
	let ptr = this.read_pointer(ptr)?;
	let len = this.read_target_usize(len)?;

	// The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
	// neither of which have any effect on our current PRNG.
	// See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
	let _flags = this.read_scalar(flags)?.to_i32();

	this.gen_random(ptr, len)?;
	this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
	Ok(())
	}