1 use rustc_span::Symbol;
2 use rustc_target::spec::abi::Abi;
5 use shims::foreign_items::EmulateByNameResult;
6 use shims::unix::fs::EvalContextExt as _;
7 use shims::unix::linux::sync::futex;
8 use shims::unix::sync::EvalContextExt as _;
9 use shims::unix::thread::EvalContextExt as _;
11 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
12 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
13 fn emulate_foreign_item_by_name(
17 args: &[OpTy<'tcx, Provenance>],
18 dest: &PlaceTy<'tcx, Provenance>,
19 ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
20 let this = self.eval_context_mut();
22 // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
24 match link_name.as_str() {
26 "__errno_location" => {
27 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
28 let errno_place = this.last_error_place()?;
29 this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
32 // File related shims (but also see "syscall" below for statx)
34 let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
35 let result = this.linux_readdir64(dirp)?;
36 this.write_scalar(result, dest)?;
39 "sync_file_range" => {
40 let [fd, offset, nbytes, flags] =
41 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
42 let result = this.sync_file_range(fd, offset, nbytes, flags)?;
43 this.write_scalar(result, dest)?;
48 // This is a POSIX function but it has only been tested on linux.
50 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
51 let result = this.clock_gettime(clk_id, tp)?;
52 this.write_scalar(result, dest)?;
56 "pthread_condattr_setclock" => {
57 let [attr, clock_id] =
58 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
59 let result = this.pthread_condattr_setclock(attr, clock_id)?;
60 this.write_scalar(result, dest)?;
62 "pthread_condattr_getclock" => {
63 let [attr, clock_id] =
64 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
65 let result = this.pthread_condattr_getclock(attr, clock_id)?;
66 this.write_scalar(result, dest)?;
68 "pthread_setname_np" => {
70 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
72 this.pthread_setname_np(this.read_scalar(thread)?, this.read_scalar(name)?)?;
73 this.write_scalar(res, dest)?;
76 // Dynamically invoked syscalls
78 // We do not use `check_shim` here because `syscall` is variadic. The argument
79 // count is checked bellow.
80 this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
81 // The syscall variadic function is legal to call with more arguments than needed,
82 // extra arguments are simply ignored. The important check is that when we use an
83 // argument, we have to also check all arguments *before* it to ensure that they
84 // have the right type.
86 let sys_getrandom = this.eval_libc("SYS_getrandom")?.to_machine_usize(this)?;
88 let sys_statx = this.eval_libc("SYS_statx")?.to_machine_usize(this)?;
90 let sys_futex = this.eval_libc("SYS_futex")?.to_machine_usize(this)?;
94 "incorrect number of arguments for syscall: got 0, expected at least 1"
97 match this.read_scalar(&args[0])?.to_machine_usize(this)? {
98 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
99 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
100 id if id == sys_getrandom => {
101 // The first argument is the syscall id, so skip over it.
104 "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
108 getrandom(this, &args[1], &args[2], &args[3], dest)?;
110 // `statx` is used by `libstd` to retrieve metadata information on `linux`
111 // instead of using `stat`,`lstat` or `fstat` as on `macos`.
112 id if id == sys_statx => {
113 // The first argument is the syscall id, so skip over it.
116 "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
121 this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
122 this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
124 // `futex` is used by some synchonization primitives.
125 id if id == sys_futex => {
126 futex(this, &args[1..], dest)?;
129 this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
130 return Ok(EmulateByNameResult::AlreadyJumped);
137 let [ptr, len, flags] =
138 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
139 getrandom(this, ptr, len, flags, dest)?;
141 "sched_getaffinity" => {
142 let [pid, cpusetsize, mask] =
143 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
144 this.read_scalar(pid)?.to_i32()?;
145 this.read_scalar(cpusetsize)?.to_machine_usize(this)?;
146 this.deref_operand(mask)?;
147 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
148 let einval = this.eval_libc("EINVAL")?;
149 this.set_last_error(einval)?;
150 this.write_scalar(Scalar::from_i32(-1), dest)?;
153 // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
154 // These shims are enabled only when the caller is in the standard library.
155 "pthread_getattr_np" if this.frame_in_std() => {
156 let [_thread, _attr] =
157 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
158 this.write_null(dest)?;
161 _ => return Ok(EmulateByNameResult::NotSupported),
164 Ok(EmulateByNameResult::NeedsJumping)
168 // Shims the linux `getrandom` syscall.
170 this: &mut MiriInterpCx<'_, 'tcx>,
171 ptr: &OpTy<'tcx, Provenance>,
172 len: &OpTy<'tcx, Provenance>,
173 flags: &OpTy<'tcx, Provenance>,
174 dest: &PlaceTy<'tcx, Provenance>,
175 ) -> InterpResult<'tcx> {
176 let ptr = this.read_pointer(ptr)?;
177 let len = this.read_scalar(len)?.to_machine_usize(this)?;
179 // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
180 // neither of which have any effect on our current PRNG.
181 // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
182 let _flags = this.read_scalar(flags)?.to_i32();
184 this.gen_random(ptr, len)?;
185 this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;