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)?;
47 "pthread_condattr_setclock" => {
48 let [attr, clock_id] =
49 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
50 let result = this.pthread_condattr_setclock(attr, clock_id)?;
51 this.write_scalar(result, dest)?;
53 "pthread_condattr_getclock" => {
54 let [attr, clock_id] =
55 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
56 let result = this.pthread_condattr_getclock(attr, clock_id)?;
57 this.write_scalar(result, dest)?;
59 "pthread_setname_np" => {
61 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
63 let res = this.pthread_setname_np(
64 this.read_scalar(thread)?,
65 this.read_scalar(name)?,
68 this.write_scalar(res, dest)?;
70 "pthread_getname_np" => {
71 let [thread, name, len] =
72 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
73 let res = this.pthread_getname_np(
74 this.read_scalar(thread)?,
75 this.read_scalar(name)?,
76 this.read_scalar(len)?,
78 this.write_scalar(res, dest)?;
81 // Dynamically invoked syscalls
83 // We do not use `check_shim` here because `syscall` is variadic. The argument
84 // count is checked bellow.
85 this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
86 // The syscall variadic function is legal to call with more arguments than needed,
87 // extra arguments are simply ignored. The important check is that when we use an
88 // argument, we have to also check all arguments *before* it to ensure that they
89 // have the right type.
91 let sys_getrandom = this.eval_libc("SYS_getrandom").to_machine_usize(this)?;
93 let sys_statx = this.eval_libc("SYS_statx").to_machine_usize(this)?;
95 let sys_futex = this.eval_libc("SYS_futex").to_machine_usize(this)?;
99 "incorrect number of arguments for syscall: got 0, expected at least 1"
102 match this.read_scalar(&args[0])?.to_machine_usize(this)? {
103 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
104 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
105 id if id == sys_getrandom => {
106 // The first argument is the syscall id, so skip over it.
109 "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
113 getrandom(this, &args[1], &args[2], &args[3], dest)?;
115 // `statx` is used by `libstd` to retrieve metadata information on `linux`
116 // instead of using `stat`,`lstat` or `fstat` as on `macos`.
117 id if id == sys_statx => {
118 // The first argument is the syscall id, so skip over it.
121 "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
126 this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
127 this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
129 // `futex` is used by some synchonization primitives.
130 id if id == sys_futex => {
131 futex(this, &args[1..], dest)?;
134 this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
135 return Ok(EmulateByNameResult::AlreadyJumped);
142 let [ptr, len, flags] =
143 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
144 getrandom(this, ptr, len, flags, dest)?;
146 "sched_getaffinity" => {
147 let [pid, cpusetsize, mask] =
148 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
149 this.read_scalar(pid)?.to_i32()?;
150 this.read_scalar(cpusetsize)?.to_machine_usize(this)?;
151 this.deref_operand(mask)?;
152 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
153 let einval = this.eval_libc("EINVAL");
154 this.set_last_error(einval)?;
155 this.write_scalar(Scalar::from_i32(-1), dest)?;
158 // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
159 // These shims are enabled only when the caller is in the standard library.
160 "pthread_getattr_np" if this.frame_in_std() => {
161 let [_thread, _attr] =
162 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
163 this.write_null(dest)?;
166 _ => return Ok(EmulateByNameResult::NotSupported),
169 Ok(EmulateByNameResult::NeedsJumping)
173 // Shims the linux `getrandom` syscall.
175 this: &mut MiriInterpCx<'_, 'tcx>,
176 ptr: &OpTy<'tcx, Provenance>,
177 len: &OpTy<'tcx, Provenance>,
178 flags: &OpTy<'tcx, Provenance>,
179 dest: &PlaceTy<'tcx, Provenance>,
180 ) -> InterpResult<'tcx> {
181 let ptr = this.read_pointer(ptr)?;
182 let len = this.read_scalar(len)?.to_machine_usize(this)?;
184 // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
185 // neither of which have any effect on our current PRNG.
186 // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
187 let _flags = this.read_scalar(flags)?.to_i32();
189 this.gen_random(ptr, len)?;
190 this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;