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 let res = this.pthread_setname_np(
73 this.read_scalar(thread)?,
74 this.read_scalar(name)?,
77 this.write_scalar(res, dest)?;
79 "pthread_getname_np" => {
80 let [thread, name, len] =
81 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
82 let res = this.pthread_getname_np(
83 this.read_scalar(thread)?,
84 this.read_scalar(name)?,
85 this.read_scalar(len)?,
87 this.write_scalar(res, dest)?;
90 // Dynamically invoked syscalls
92 // We do not use `check_shim` here because `syscall` is variadic. The argument
93 // count is checked bellow.
94 this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
95 // The syscall variadic function is legal to call with more arguments than needed,
96 // extra arguments are simply ignored. The important check is that when we use an
97 // argument, we have to also check all arguments *before* it to ensure that they
98 // have the right type.
100 let sys_getrandom = this.eval_libc("SYS_getrandom")?.to_machine_usize(this)?;
102 let sys_statx = this.eval_libc("SYS_statx")?.to_machine_usize(this)?;
104 let sys_futex = this.eval_libc("SYS_futex")?.to_machine_usize(this)?;
108 "incorrect number of arguments for syscall: got 0, expected at least 1"
111 match this.read_scalar(&args[0])?.to_machine_usize(this)? {
112 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
113 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
114 id if id == sys_getrandom => {
115 // The first argument is the syscall id, so skip over it.
118 "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
122 getrandom(this, &args[1], &args[2], &args[3], dest)?;
124 // `statx` is used by `libstd` to retrieve metadata information on `linux`
125 // instead of using `stat`,`lstat` or `fstat` as on `macos`.
126 id if id == sys_statx => {
127 // The first argument is the syscall id, so skip over it.
130 "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
135 this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
136 this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
138 // `futex` is used by some synchonization primitives.
139 id if id == sys_futex => {
140 futex(this, &args[1..], dest)?;
143 this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
144 return Ok(EmulateByNameResult::AlreadyJumped);
151 let [ptr, len, flags] =
152 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
153 getrandom(this, ptr, len, flags, dest)?;
155 "sched_getaffinity" => {
156 let [pid, cpusetsize, mask] =
157 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
158 this.read_scalar(pid)?.to_i32()?;
159 this.read_scalar(cpusetsize)?.to_machine_usize(this)?;
160 this.deref_operand(mask)?;
161 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
162 let einval = this.eval_libc("EINVAL")?;
163 this.set_last_error(einval)?;
164 this.write_scalar(Scalar::from_i32(-1), dest)?;
167 // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
168 // These shims are enabled only when the caller is in the standard library.
169 "pthread_getattr_np" if this.frame_in_std() => {
170 let [_thread, _attr] =
171 this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
172 this.write_null(dest)?;
175 _ => return Ok(EmulateByNameResult::NotSupported),
178 Ok(EmulateByNameResult::NeedsJumping)
182 // Shims the linux `getrandom` syscall.
184 this: &mut MiriInterpCx<'_, 'tcx>,
185 ptr: &OpTy<'tcx, Provenance>,
186 len: &OpTy<'tcx, Provenance>,
187 flags: &OpTy<'tcx, Provenance>,
188 dest: &PlaceTy<'tcx, Provenance>,
189 ) -> InterpResult<'tcx> {
190 let ptr = this.read_pointer(ptr)?;
191 let len = this.read_scalar(len)?.to_machine_usize(this)?;
193 // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
194 // neither of which have any effect on our current PRNG.
195 // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
196 let _flags = this.read_scalar(flags)?.to_i32();
198 this.gen_random(ptr, len)?;
199 this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;