src/shims/foreign_items.rs

   1 use rustc::ty::layout::{Align, LayoutOf, Size};
   2 use rustc::hir::def_id::DefId;
   3 use rustc::mir;
   4 use syntax::attr;
   5 use syntax::symbol::sym;
   6
   7 use rand::RngCore;
   8
   9 use crate::*;
  10
  11 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  12 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  13     /// Returns the minimum alignment for the target architecture for allocations of the given size.
  14     fn min_align(&self, size: u64, kind: MiriMemoryKind) -> Align {
  15         let this = self.eval_context_ref();
  16         // List taken from `libstd/sys_common/alloc.rs`.
  17         let min_align = match this.tcx.tcx.sess.target.target.arch.as_str() {
  18             "x86" | "arm" | "mips" | "powerpc" | "powerpc64" | "asmjs" | "wasm32" => 8,
  19             "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" => 16,
  20             arch => bug!("Unsupported target architecture: {}", arch),
  21         };
  22         // Windows always aligns, even small allocations.
  23         // Source: <https://support.microsoft.com/en-us/help/286470/how-to-use-pageheap-exe-in-windows-xp-windows-2000-and-windows-server>
  24         // But jemalloc does not, so for the C heap we only align if the allocation is sufficiently big.
  25         if kind == MiriMemoryKind::WinHeap || size >= min_align {
  26             return Align::from_bytes(min_align).unwrap();
  27         }
  28         // We have `size < min_align`. Round `size` *down* to the next power of two and use that.
  29         fn prev_power_of_two(x: u64) -> u64 {
  30             let next_pow2 = x.next_power_of_two();
  31             if next_pow2 == x {
  32                 // x *is* a power of two, just use that.
  33                 x
  34             } else {
  35                 // x is between two powers, so next = 2*prev.
  36                 next_pow2 / 2
  37             }
  38         }
  39         Align::from_bytes(prev_power_of_two(size)).unwrap()
  40     }
  41
  42     fn malloc(
  43         &mut self,
  44         size: u64,
  45         zero_init: bool,
  46         kind: MiriMemoryKind,
  47     ) -> Scalar<Tag> {
  48         let this = self.eval_context_mut();
  49         let tcx = &{this.tcx.tcx};
  50         if size == 0 {
  51             Scalar::from_int(0, this.pointer_size())
  52         } else {
  53             let align = this.min_align(size, kind);
  54             let ptr = this.memory_mut().allocate(Size::from_bytes(size), align, kind.into());
  55             if zero_init {
  56                 // We just allocated this, the access cannot fail
  57                 this.memory_mut()
  58                     .get_mut(ptr.alloc_id).unwrap()
  59                     .write_repeat(tcx, ptr, 0, Size::from_bytes(size)).unwrap();
  60             }
  61             Scalar::Ptr(ptr)
  62         }
  63     }
  64
  65     fn free(
  66         &mut self,
  67         ptr: Scalar<Tag>,
  68         kind: MiriMemoryKind,
  69     ) -> InterpResult<'tcx> {
  70         let this = self.eval_context_mut();
  71         if !this.is_null(ptr)? {
  72             let ptr = this.force_ptr(ptr)?;
  73             this.memory_mut().deallocate(
  74                 ptr,
  75                 None,
  76                 kind.into(),
  77             )?;
  78         }
  79         Ok(())
  80     }
  81
  82     fn realloc(
  83         &mut self,
  84         old_ptr: Scalar<Tag>,
  85         new_size: u64,
  86         kind: MiriMemoryKind,
  87     ) -> InterpResult<'tcx, Scalar<Tag>> {
  88         let this = self.eval_context_mut();
  89         let new_align = this.min_align(new_size, kind);
  90         if this.is_null(old_ptr)? {
  91             if new_size == 0 {
  92                 Ok(Scalar::from_int(0, this.pointer_size()))
  93             } else {
  94                 let new_ptr = this.memory_mut().allocate(
  95                     Size::from_bytes(new_size),
  96                     new_align,
  97                     kind.into()
  98                 );
  99                 Ok(Scalar::Ptr(new_ptr))
 100             }
 101         } else {
 102             let old_ptr = this.force_ptr(old_ptr)?;
 103             let memory = this.memory_mut();
 104             if new_size == 0 {
 105                 memory.deallocate(
 106                     old_ptr,
 107                     None,
 108                     kind.into(),
 109                 )?;
 110                 Ok(Scalar::from_int(0, this.pointer_size()))
 111             } else {
 112                 let new_ptr = memory.reallocate(
 113                     old_ptr,
 114                     None,
 115                     Size::from_bytes(new_size),
 116                     new_align,
 117                     kind.into(),
 118                 )?;
 119                 Ok(Scalar::Ptr(new_ptr))
 120             }
 121         }
 122     }
 123
 124     /// Emulates calling a foreign item, failing if the item is not supported.
 125     /// This function will handle `goto_block` if needed.
 126     fn emulate_foreign_item(
 127         &mut self,
 128         def_id: DefId,
 129         args: &[OpTy<'tcx, Tag>],
 130         dest: Option<PlaceTy<'tcx, Tag>>,
 131         ret: Option<mir::BasicBlock>,
 132     ) -> InterpResult<'tcx> {
 133         let this = self.eval_context_mut();
 134         let attrs = this.tcx.get_attrs(def_id);
 135         let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
 136             Some(name) => name.as_str(),
 137             None => this.tcx.item_name(def_id).as_str(),
 138         };
 139         // Strip linker suffixes (seen on 32-bit macOS).
 140         let link_name = link_name.get().trim_end_matches("$UNIX2003");
 141         let tcx = &{this.tcx.tcx};
 142
 143         // First: functions that diverge.
 144         match link_name {
 145             "__rust_start_panic" | "panic_impl" => {
 146                 return err!(MachineError("the evaluated program panicked".to_string()));
 147             }
 148             "exit" | "ExitProcess" => {
 149                 // it's really u32 for ExitProcess, but we have to put it into the `Exit` error variant anyway
 150                 let code = this.read_scalar(args[0])?.to_i32()?;
 151                 return err!(Exit(code));
 152             }
 153             _ => if dest.is_none() {
 154                 return err!(Unimplemented(
 155                     format!("can't call diverging foreign function: {}", link_name),
 156                 ));
 157             }
 158         }
 159
 160         // Next: functions that assume a ret and dest.
 161         let dest = dest.expect("we already checked for a dest");
 162         let ret = ret.expect("dest is `Some` but ret is `None`");
 163         match link_name {
 164             "malloc" => {
 165                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 166                 let res = this.malloc(size, /*zero_init:*/ false, MiriMemoryKind::C);
 167                 this.write_scalar(res, dest)?;
 168             }
 169             "calloc" => {
 170                 let items = this.read_scalar(args[0])?.to_usize(this)?;
 171                 let len = this.read_scalar(args[1])?.to_usize(this)?;
 172                 let size = items.checked_mul(len).ok_or_else(|| InterpError::Overflow(mir::BinOp::Mul))?;
 173                 let res = this.malloc(size, /*zero_init:*/ true, MiriMemoryKind::C);
 174                 this.write_scalar(res, dest)?;
 175             }
 176             "posix_memalign" => {
 177                 let ret = this.deref_operand(args[0])?;
 178                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 179                 let size = this.read_scalar(args[2])?.to_usize(this)?;
 180                 // Align must be power of 2, and also at least ptr-sized (POSIX rules).
 181                 if !align.is_power_of_two() {
 182                     return err!(HeapAllocNonPowerOfTwoAlignment(align));
 183                 }
 184                 /*
 185                 FIXME: This check is disabled because rustc violates it.
 186                 See <https://github.com/rust-lang/rust/issues/62251>.
 187                 if align < this.pointer_size().bytes() {
 188                     return err!(MachineError(format!(
 189                         "posix_memalign: alignment must be at least the size of a pointer, but is {}",
 190                         align,
 191                     )));
 192                 }
 193                 */
 194                 if size == 0 {
 195                     this.write_null(ret.into())?;
 196                 } else {
 197                     let ptr = this.memory_mut().allocate(
 198                         Size::from_bytes(size),
 199                         Align::from_bytes(align).unwrap(),
 200                         MiriMemoryKind::C.into()
 201                     );
 202                     this.write_scalar(Scalar::Ptr(ptr), ret.into())?;
 203                 }
 204                 this.write_null(dest)?;
 205             }
 206             "free" => {
 207                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 208                 this.free(ptr, MiriMemoryKind::C)?;
 209             }
 210             "realloc" => {
 211                 let old_ptr = this.read_scalar(args[0])?.not_undef()?;
 212                 let new_size = this.read_scalar(args[1])?.to_usize(this)?;
 213                 let res = this.realloc(old_ptr, new_size, MiriMemoryKind::C)?;
 214                 this.write_scalar(res, dest)?;
 215             }
 216
 217             "__rust_alloc" => {
 218                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 219                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 220                 if size == 0 {
 221                     return err!(HeapAllocZeroBytes);
 222                 }
 223                 if !align.is_power_of_two() {
 224                     return err!(HeapAllocNonPowerOfTwoAlignment(align));
 225                 }
 226                 let ptr = this.memory_mut()
 227                     .allocate(
 228                         Size::from_bytes(size),
 229                         Align::from_bytes(align).unwrap(),
 230                         MiriMemoryKind::Rust.into()
 231                     );
 232                 this.write_scalar(Scalar::Ptr(ptr), dest)?;
 233             }
 234             "__rust_alloc_zeroed" => {
 235                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 236                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 237                 if size == 0 {
 238                     return err!(HeapAllocZeroBytes);
 239                 }
 240                 if !align.is_power_of_two() {
 241                     return err!(HeapAllocNonPowerOfTwoAlignment(align));
 242                 }
 243                 let ptr = this.memory_mut()
 244                     .allocate(
 245                         Size::from_bytes(size),
 246                         Align::from_bytes(align).unwrap(),
 247                         MiriMemoryKind::Rust.into()
 248                     );
 249                 // We just allocated this, the access cannot fail
 250                 this.memory_mut()
 251                     .get_mut(ptr.alloc_id).unwrap()
 252                     .write_repeat(tcx, ptr, 0, Size::from_bytes(size)).unwrap();
 253                 this.write_scalar(Scalar::Ptr(ptr), dest)?;
 254             }
 255             "__rust_dealloc" => {
 256                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 257                 let old_size = this.read_scalar(args[1])?.to_usize(this)?;
 258                 let align = this.read_scalar(args[2])?.to_usize(this)?;
 259                 if old_size == 0 {
 260                     return err!(HeapAllocZeroBytes);
 261                 }
 262                 if !align.is_power_of_two() {
 263                     return err!(HeapAllocNonPowerOfTwoAlignment(align));
 264                 }
 265                 let ptr = this.force_ptr(ptr)?;
 266                 this.memory_mut().deallocate(
 267                     ptr,
 268                     Some((Size::from_bytes(old_size), Align::from_bytes(align).unwrap())),
 269                     MiriMemoryKind::Rust.into(),
 270                 )?;
 271             }
 272             "__rust_realloc" => {
 273                 let ptr = this.read_scalar(args[0])?.to_ptr()?;
 274                 let old_size = this.read_scalar(args[1])?.to_usize(this)?;
 275                 let align = this.read_scalar(args[2])?.to_usize(this)?;
 276                 let new_size = this.read_scalar(args[3])?.to_usize(this)?;
 277                 if old_size == 0 || new_size == 0 {
 278                     return err!(HeapAllocZeroBytes);
 279                 }
 280                 if !align.is_power_of_two() {
 281                     return err!(HeapAllocNonPowerOfTwoAlignment(align));
 282                 }
 283                 let align = Align::from_bytes(align).unwrap();
 284                 let new_ptr = this.memory_mut().reallocate(
 285                     ptr,
 286                     Some((Size::from_bytes(old_size), align)),
 287                     Size::from_bytes(new_size),
 288                     align,
 289                     MiriMemoryKind::Rust.into(),
 290                 )?;
 291                 this.write_scalar(Scalar::Ptr(new_ptr), dest)?;
 292             }
 293
 294             "syscall" => {
 295                 let sys_getrandom = this.eval_path_scalar(&["libc", "SYS_getrandom"])?
 296                     .expect("Failed to get libc::SYS_getrandom")
 297                     .to_usize(this)?;
 298
 299                 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
 300                 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
 301                 match this.read_scalar(args[0])?.to_usize(this)? {
 302                     id if id == sys_getrandom => {
 303                         let ptr = this.read_scalar(args[1])?.not_undef()?;
 304                         let len = this.read_scalar(args[2])?.to_usize(this)?;
 305
 306                         // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
 307                         // neither of which have any effect on our current PRNG
 308                         let _flags = this.read_scalar(args[3])?.to_i32()?;
 309
 310                         this.gen_random(len as usize, ptr)?;
 311                         this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
 312                     }
 313                     id => {
 314                         return err!(Unimplemented(
 315                             format!("miri does not support syscall ID {}", id),
 316                         ))
 317                     }
 318                 }
 319             }
 320
 321             "dlsym" => {
 322                 let _handle = this.read_scalar(args[0])?;
 323                 let symbol = this.read_scalar(args[1])?.to_ptr()?;
 324                 let symbol_name = this.memory().get(symbol.alloc_id)?.read_c_str(tcx, symbol)?;
 325                 let err = format!("bad c unicode symbol: {:?}", symbol_name);
 326                 let symbol_name = ::std::str::from_utf8(symbol_name).unwrap_or(&err);
 327                 if let Some(dlsym) = Dlsym::from_str(symbol_name)? {
 328                     let ptr = this.memory_mut().create_fn_alloc(FnVal::Other(dlsym));
 329                     this.write_scalar(Scalar::from(ptr), dest)?;
 330                 } else {
 331                     this.write_null(dest)?;
 332                 }
 333             }
 334
 335             "__rust_maybe_catch_panic" => {
 336                 // fn __rust_maybe_catch_panic(
 337                 //     f: fn(*mut u8),
 338                 //     data: *mut u8,
 339                 //     data_ptr: *mut usize,
 340                 //     vtable_ptr: *mut usize,
 341                 // ) -> u32
 342                 // We abort on panic, so not much is going on here, but we still have to call the closure.
 343                 let f = this.read_scalar(args[0])?.to_ptr()?;
 344                 let data = this.read_scalar(args[1])?.not_undef()?;
 345                 let f_instance = this.memory().get_fn(f)?.as_instance()?;
 346                 this.write_null(dest)?;
 347                 trace!("__rust_maybe_catch_panic: {:?}", f_instance);
 348
 349                 // Now we make a function call.
 350                 // TODO: consider making this reusable? `InterpCx::step` does something similar
 351                 // for the TLS destructors, and of course `eval_main`.
 352                 let mir = this.load_mir(f_instance.def)?;
 353                 let ret_place = MPlaceTy::dangling(this.layout_of(this.tcx.mk_unit())?, this).into();
 354                 this.push_stack_frame(
 355                     f_instance,
 356                     mir.span,
 357                     mir,
 358                     Some(ret_place),
 359                     // Directly return to caller.
 360                     StackPopCleanup::Goto(Some(ret)),
 361                 )?;
 362                 let mut args = this.frame().body.args_iter();
 363
 364                 let arg_local = args.next().ok_or_else(||
 365                     InterpError::AbiViolation(
 366                         "Argument to __rust_maybe_catch_panic does not take enough arguments."
 367                             .to_owned(),
 368                     ),
 369                 )?;
 370                 let arg_dest = this.eval_place(&mir::Place::Base(mir::PlaceBase::Local(arg_local)))?;
 371                 this.write_scalar(data, arg_dest)?;
 372
 373                 assert!(args.next().is_none(), "__rust_maybe_catch_panic argument has more arguments than expected");
 374
 375                 // We ourselves will return `0`, eventually (because we will not return if we paniced).
 376                 this.write_null(dest)?;
 377
 378                 // Don't fall through, we do *not* want to `goto_block`!
 379                 return Ok(());
 380             }
 381
 382             "memcmp" => {
 383                 let left = this.read_scalar(args[0])?.not_undef()?;
 384                 let right = this.read_scalar(args[1])?.not_undef()?;
 385                 let n = Size::from_bytes(this.read_scalar(args[2])?.to_usize(this)?);
 386
 387                 let result = {
 388                     let left_bytes = this.memory().read_bytes(left, n)?;
 389                     let right_bytes = this.memory().read_bytes(right, n)?;
 390
 391                     use std::cmp::Ordering::*;
 392                     match left_bytes.cmp(right_bytes) {
 393                         Less => -1i32,
 394                         Equal => 0,
 395                         Greater => 1,
 396                     }
 397                 };
 398
 399                 this.write_scalar(
 400                     Scalar::from_int(result, Size::from_bits(32)),
 401                     dest,
 402                 )?;
 403             }
 404
 405             "memrchr" => {
 406                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 407                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 408                 let num = this.read_scalar(args[2])?.to_usize(this)?;
 409                 if let Some(idx) = this.memory().read_bytes(ptr, Size::from_bytes(num))?
 410                     .iter().rev().position(|&c| c == val)
 411                 {
 412                     let new_ptr = ptr.ptr_offset(Size::from_bytes(num - idx as u64 - 1), this)?;
 413                     this.write_scalar(new_ptr, dest)?;
 414                 } else {
 415                     this.write_null(dest)?;
 416                 }
 417             }
 418
 419             "memchr" => {
 420                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 421                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 422                 let num = this.read_scalar(args[2])?.to_usize(this)?;
 423                 let idx = this
 424                     .memory()
 425                     .read_bytes(ptr, Size::from_bytes(num))?
 426                     .iter()
 427                     .position(|&c| c == val);
 428                 if let Some(idx) = idx {
 429                     let new_ptr = ptr.ptr_offset(Size::from_bytes(idx as u64), this)?;
 430                     this.write_scalar(new_ptr, dest)?;
 431                 } else {
 432                     this.write_null(dest)?;
 433                 }
 434             }
 435
 436             "getenv" => {
 437                 let result = {
 438                     let name_ptr = this.read_scalar(args[0])?.to_ptr()?;
 439                     let name = this.memory().get(name_ptr.alloc_id)?.read_c_str(tcx, name_ptr)?;
 440                     match this.machine.env_vars.get(name) {
 441                         Some(&var) => Scalar::Ptr(var),
 442                         None => Scalar::ptr_null(&*this.tcx),
 443                     }
 444                 };
 445                 this.write_scalar(result, dest)?;
 446             }
 447
 448             "unsetenv" => {
 449                 let mut success = None;
 450                 {
 451                     let name_ptr = this.read_scalar(args[0])?.not_undef()?;
 452                     if !this.is_null(name_ptr)? {
 453                         let name_ptr = name_ptr.to_ptr()?;
 454                         let name = this
 455                             .memory()
 456                             .get(name_ptr.alloc_id)?
 457                             .read_c_str(tcx, name_ptr)?
 458                             .to_owned();
 459                         if !name.is_empty() && !name.contains(&b'=') {
 460                             success = Some(this.machine.env_vars.remove(&name));
 461                         }
 462                     }
 463                 }
 464                 if let Some(old) = success {
 465                     if let Some(var) = old {
 466                         this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
 467                     }
 468                     this.write_null(dest)?;
 469                 } else {
 470                     this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 471                 }
 472             }
 473
 474             "setenv" => {
 475                 let mut new = None;
 476                 {
 477                     let name_ptr = this.read_scalar(args[0])?.not_undef()?;
 478                     let value_ptr = this.read_scalar(args[1])?.to_ptr()?;
 479                     let value = this.memory().get(value_ptr.alloc_id)?.read_c_str(tcx, value_ptr)?;
 480                     if !this.is_null(name_ptr)? {
 481                         let name_ptr = name_ptr.to_ptr()?;
 482                         let name = this.memory().get(name_ptr.alloc_id)?.read_c_str(tcx, name_ptr)?;
 483                         if !name.is_empty() && !name.contains(&b'=') {
 484                             new = Some((name.to_owned(), value.to_owned()));
 485                         }
 486                     }
 487                 }
 488                 if let Some((name, value)) = new {
 489                     // `+1` for the null terminator.
 490                     let value_copy = this.memory_mut().allocate(
 491                         Size::from_bytes((value.len() + 1) as u64),
 492                         Align::from_bytes(1).unwrap(),
 493                         MiriMemoryKind::Env.into(),
 494                     );
 495                     // We just allocated these, so the write cannot fail.
 496                     let alloc = this.memory_mut().get_mut(value_copy.alloc_id).unwrap();
 497                     alloc.write_bytes(tcx, value_copy, &value).unwrap();
 498                     let trailing_zero_ptr = value_copy.offset(
 499                         Size::from_bytes(value.len() as u64),
 500                         tcx,
 501                     ).unwrap();
 502                     alloc.write_bytes(tcx, trailing_zero_ptr, &[0]).unwrap();
 503
 504                     if let Some(var) = this.machine.env_vars.insert(
 505                         name.to_owned(),
 506                         value_copy,
 507                     )
 508                     {
 509                         this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
 510                     }
 511                     this.write_null(dest)?;
 512                 } else {
 513                     this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 514                 }
 515             }
 516
 517             "write" => {
 518                 let fd = this.read_scalar(args[0])?.to_i32()?;
 519                 let buf = this.read_scalar(args[1])?.not_undef()?;
 520                 let n = this.read_scalar(args[2])?.to_usize(&*this.tcx)?;
 521                 trace!("Called write({:?}, {:?}, {:?})", fd, buf, n);
 522                 let result = if fd == 1 || fd == 2 {
 523                     // stdout/stderr
 524                     use std::io::{self, Write};
 525
 526                     let buf_cont = this.memory().read_bytes(buf, Size::from_bytes(n))?;
 527                     // We need to flush to make sure this actually appears on the screen
 528                     let res = if fd == 1 {
 529                         // Stdout is buffered, flush to make sure it appears on the screen.
 530                         // This is the write() syscall of the interpreted program, we want it
 531                         // to correspond to a write() syscall on the host -- there is no good
 532                         // in adding extra buffering here.
 533                         let res = io::stdout().write(buf_cont);
 534                         io::stdout().flush().unwrap();
 535                         res
 536                     } else {
 537                         // No need to flush, stderr is not buffered.
 538                         io::stderr().write(buf_cont)
 539                     };
 540                     match res {
 541                         Ok(n) => n as i64,
 542                         Err(_) => -1,
 543                     }
 544                 } else {
 545                     eprintln!("Miri: Ignored output to FD {}", fd);
 546                     // Pretend it all went well.
 547                     n as i64
 548                 };
 549                 // Now, `result` is the value we return back to the program.
 550                 this.write_scalar(
 551                     Scalar::from_int(result, dest.layout.size),
 552                     dest,
 553                 )?;
 554             }
 555
 556             "strlen" => {
 557                 let ptr = this.read_scalar(args[0])?.to_ptr()?;
 558                 let n = this.memory().get(ptr.alloc_id)?.read_c_str(tcx, ptr)?.len();
 559                 this.write_scalar(Scalar::from_uint(n as u64, dest.layout.size), dest)?;
 560             }
 561
 562             // math functions
 563
 564             "cbrtf" | "coshf" | "sinhf" |"tanf" => {
 565                 // FIXME: Using host floats.
 566                 let f = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 567                 let f = match link_name {
 568                     "cbrtf" => f.cbrt(),
 569                     "coshf" => f.cosh(),
 570                     "sinhf" => f.sinh(),
 571                     "tanf" => f.tan(),
 572                     _ => bug!(),
 573                 };
 574                 this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
 575             }
 576             // underscore case for windows
 577             "_hypotf" | "hypotf" | "atan2f" => {
 578                 // FIXME: Using host floats.
 579                 let f1 = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 580                 let f2 = f32::from_bits(this.read_scalar(args[1])?.to_u32()?);
 581                 let n = match link_name {
 582                     "_hypotf" | "hypotf" => f1.hypot(f2),
 583                     "atan2f" => f1.atan2(f2),
 584                     _ => bug!(),
 585                 };
 586                 this.write_scalar(Scalar::from_u32(n.to_bits()), dest)?;
 587             }
 588
 589             "cbrt" | "cosh" | "sinh" | "tan" => {
 590                 // FIXME: Using host floats.
 591                 let f = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 592                 let f = match link_name {
 593                     "cbrt" => f.cbrt(),
 594                     "cosh" => f.cosh(),
 595                     "sinh" => f.sinh(),
 596                     "tan" => f.tan(),
 597                     _ => bug!(),
 598                 };
 599                 this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
 600             }
 601             // underscore case for windows
 602             "_hypot" | "hypot" | "atan2" => {
 603                 // FIXME: Using host floats.
 604                 let f1 = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 605                 let f2 = f64::from_bits(this.read_scalar(args[1])?.to_u64()?);
 606                 let n = match link_name {
 607                     "_hypot" | "hypot" => f1.hypot(f2),
 608                     "atan2" => f1.atan2(f2),
 609                     _ => bug!(),
 610                 };
 611                 this.write_scalar(Scalar::from_u64(n.to_bits()), dest)?;
 612             }
 613
 614             // Some things needed for `sys::thread` initialization to go through.
 615             "signal" | "sigaction" | "sigaltstack" => {
 616                 this.write_scalar(Scalar::from_int(0, dest.layout.size), dest)?;
 617             }
 618
 619             "sysconf" => {
 620                 let name = this.read_scalar(args[0])?.to_i32()?;
 621
 622                 trace!("sysconf() called with name {}", name);
 623                 // TODO: Cache the sysconf integers via Miri's global cache.
 624                 let paths = &[
 625                     (&["libc", "_SC_PAGESIZE"], Scalar::from_int(PAGE_SIZE, dest.layout.size)),
 626                     (&["libc", "_SC_GETPW_R_SIZE_MAX"], Scalar::from_int(-1, dest.layout.size)),
 627                     (&["libc", "_SC_NPROCESSORS_ONLN"], Scalar::from_int(NUM_CPUS, dest.layout.size)),
 628                 ];
 629                 let mut result = None;
 630                 for &(path, path_value) in paths {
 631                     if let Some(val) = this.eval_path_scalar(path)? {
 632                         let val = val.to_i32()?;
 633                         if val == name {
 634                             result = Some(path_value);
 635                             break;
 636                         }
 637
 638                     }
 639                 }
 640                 if let Some(result) = result {
 641                     this.write_scalar(result, dest)?;
 642                 } else {
 643                     return err!(Unimplemented(
 644                         format!("Unimplemented sysconf name: {}", name),
 645                     ));
 646                 }
 647             }
 648
 649             "sched_getaffinity" => {
 650                 // Return an error; `num_cpus` then falls back to `sysconf`.
 651                 this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 652             }
 653
 654             "isatty" => {
 655                 this.write_null(dest)?;
 656             }
 657
 658             // Hook pthread calls that go to the thread-local storage memory subsystem.
 659             "pthread_key_create" => {
 660                 let key_ptr = this.read_scalar(args[0])?.not_undef()?;
 661
 662                 // Extract the function type out of the signature (that seems easier than constructing it ourselves).
 663                 let dtor = match this.test_null(this.read_scalar(args[1])?.not_undef()?)? {
 664                     Some(dtor_ptr) => Some(this.memory().get_fn(dtor_ptr)?.as_instance()?),
 665                     None => None,
 666                 };
 667
 668                 // Figure out how large a pthread TLS key actually is.
 669                 // This is `libc::pthread_key_t`.
 670                 let key_type = args[0].layout.ty
 671                     .builtin_deref(true)
 672                     .ok_or_else(|| InterpError::AbiViolation("wrong signature used for `pthread_key_create`: first argument must be a raw pointer.".to_owned()))?
 673                     .ty;
 674                 let key_layout = this.layout_of(key_type)?;
 675
 676                 // Create key and write it into the memory where `key_ptr` wants it.
 677                 let key = this.machine.tls.create_tls_key(dtor) as u128;
 678                 if key_layout.size.bits() < 128 && key >= (1u128 << key_layout.size.bits() as u128) {
 679                     return err!(OutOfTls);
 680                 }
 681
 682                 let key_ptr = this.memory().check_ptr_access(key_ptr, key_layout.size, key_layout.align.abi)?
 683                     .expect("cannot be a ZST");
 684                 this.memory_mut().get_mut(key_ptr.alloc_id)?.write_scalar(
 685                     tcx,
 686                     key_ptr,
 687                     Scalar::from_uint(key, key_layout.size).into(),
 688                     key_layout.size,
 689                 )?;
 690
 691                 // Return success (`0`).
 692                 this.write_null(dest)?;
 693             }
 694             "pthread_key_delete" => {
 695                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 696                 this.machine.tls.delete_tls_key(key)?;
 697                 // Return success (0)
 698                 this.write_null(dest)?;
 699             }
 700             "pthread_getspecific" => {
 701                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 702                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 703                 this.write_scalar(ptr, dest)?;
 704             }
 705             "pthread_setspecific" => {
 706                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 707                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 708                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 709
 710                 // Return success (`0`).
 711                 this.write_null(dest)?;
 712             }
 713
 714             // Stack size/address stuff.
 715             "pthread_attr_init" | "pthread_attr_destroy" | "pthread_self" |
 716             "pthread_attr_setstacksize" => {
 717                 this.write_null(dest)?;
 718             }
 719             "pthread_attr_getstack" => {
 720                 let addr_place = this.deref_operand(args[1])?;
 721                 let size_place = this.deref_operand(args[2])?;
 722
 723                 this.write_scalar(
 724                     Scalar::from_uint(STACK_ADDR, addr_place.layout.size),
 725                     addr_place.into(),
 726                 )?;
 727                 this.write_scalar(
 728                     Scalar::from_uint(STACK_SIZE, size_place.layout.size),
 729                     size_place.into(),
 730                 )?;
 731
 732                 // Return success (`0`).
 733                 this.write_null(dest)?;
 734             }
 735
 736             // We don't support threading.
 737             "pthread_create" => {
 738                 return err!(Unimplemented(format!("Miri does not support threading")));
 739             }
 740
 741             // Stub out calls for condvar, mutex and rwlock, to just return `0`.
 742             "pthread_mutexattr_init" | "pthread_mutexattr_settype" | "pthread_mutex_init" |
 743             "pthread_mutexattr_destroy" | "pthread_mutex_lock" | "pthread_mutex_unlock" |
 744             "pthread_mutex_destroy" | "pthread_rwlock_rdlock" | "pthread_rwlock_unlock" |
 745             "pthread_rwlock_wrlock" | "pthread_rwlock_destroy" | "pthread_condattr_init" |
 746             "pthread_condattr_setclock" | "pthread_cond_init" | "pthread_condattr_destroy" |
 747             "pthread_cond_destroy" => {
 748                 this.write_null(dest)?;
 749             }
 750
 751             // We don't support fork so we don't have to do anything for atfork.
 752             "pthread_atfork" => {
 753                 this.write_null(dest)?;
 754             }
 755
 756             "mmap" => {
 757                 // This is a horrible hack, but since the guard page mechanism calls mmap and expects a particular return value, we just give it that value.
 758                 let addr = this.read_scalar(args[0])?.not_undef()?;
 759                 this.write_scalar(addr, dest)?;
 760             }
 761             "mprotect" => {
 762                 this.write_null(dest)?;
 763             }
 764
 765             // macOS API stubs.
 766             "pthread_attr_get_np" | "pthread_getattr_np" => {
 767                 this.write_null(dest)?;
 768             }
 769             "pthread_get_stackaddr_np" => {
 770                 let stack_addr = Scalar::from_uint(STACK_ADDR, dest.layout.size);
 771                 this.write_scalar(stack_addr, dest)?;
 772             }
 773             "pthread_get_stacksize_np" => {
 774                 let stack_size = Scalar::from_uint(STACK_SIZE, dest.layout.size);
 775                 this.write_scalar(stack_size, dest)?;
 776             }
 777             "_tlv_atexit" => {
 778                 // FIXME: register the destructor.
 779             },
 780             "_NSGetArgc" => {
 781                 this.write_scalar(Scalar::Ptr(this.machine.argc.unwrap()), dest)?;
 782             },
 783             "_NSGetArgv" => {
 784                 this.write_scalar(Scalar::Ptr(this.machine.argv.unwrap()), dest)?;
 785             },
 786             "SecRandomCopyBytes" => {
 787                 let len = this.read_scalar(args[1])?.to_usize(this)?;
 788                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 789                 this.gen_random(len as usize, ptr)?;
 790                 this.write_null(dest)?;
 791             }
 792
 793             // Windows API stubs.
 794             // HANDLE = isize
 795             // DWORD = ULONG = u32
 796             // BOOL = i32
 797             "GetProcessHeap" => {
 798                 // Just fake a HANDLE
 799                 this.write_scalar(Scalar::from_int(1, this.pointer_size()), dest)?;
 800             }
 801             "HeapAlloc" => {
 802                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 803                 let flags = this.read_scalar(args[1])?.to_u32()?;
 804                 let size = this.read_scalar(args[2])?.to_usize(this)?;
 805                 let zero_init = (flags & 0x00000008) != 0; // HEAP_ZERO_MEMORY
 806                 let res = this.malloc(size, zero_init, MiriMemoryKind::WinHeap);
 807                 this.write_scalar(res, dest)?;
 808             }
 809             "HeapFree" => {
 810                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 811                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 812                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 813                 this.free(ptr, MiriMemoryKind::WinHeap)?;
 814                 this.write_scalar(Scalar::from_int(1, Size::from_bytes(4)), dest)?;
 815             }
 816             "HeapReAlloc" => {
 817                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 818                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 819                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 820                 let size = this.read_scalar(args[3])?.to_usize(this)?;
 821                 let res = this.realloc(ptr, size, MiriMemoryKind::WinHeap)?;
 822                 this.write_scalar(res, dest)?;
 823             }
 824
 825             "SetLastError" => {
 826                 let err = this.read_scalar(args[0])?.to_u32()?;
 827                 this.machine.last_error = err;
 828             }
 829             "GetLastError" => {
 830                 this.write_scalar(Scalar::from_u32(this.machine.last_error), dest)?;
 831             }
 832
 833             "AddVectoredExceptionHandler" => {
 834                 // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
 835                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 836             },
 837             "InitializeCriticalSection" |
 838             "EnterCriticalSection" |
 839             "LeaveCriticalSection" |
 840             "DeleteCriticalSection" => {
 841                 // Nothing to do, not even a return value.
 842             },
 843             "GetModuleHandleW" |
 844             "GetProcAddress" |
 845             "TryEnterCriticalSection" |
 846             "GetConsoleScreenBufferInfo" |
 847             "SetConsoleTextAttribute" => {
 848                 // Pretend these do not exist / nothing happened, by returning zero.
 849                 this.write_null(dest)?;
 850             },
 851             "GetSystemInfo" => {
 852                 let system_info = this.deref_operand(args[0])?;
 853                 let (system_info_ptr, align) = system_info.to_scalar_ptr_align();
 854                 let system_info_ptr = this.memory()
 855                     .check_ptr_access(
 856                         system_info_ptr,
 857                         system_info.layout.size,
 858                         align,
 859                     )?
 860                     .expect("cannot be a ZST");
 861                 // Initialize with `0`.
 862                 this.memory_mut().get_mut(system_info_ptr.alloc_id)?
 863                     .write_repeat(tcx, system_info_ptr, 0, system_info.layout.size)?;
 864                 // Set number of processors.
 865                 let dword_size = Size::from_bytes(4);
 866                 let offset = 2*dword_size + 3*tcx.pointer_size();
 867                 this.memory_mut().get_mut(system_info_ptr.alloc_id)?
 868                     .write_scalar(
 869                         tcx,
 870                         system_info_ptr.offset(offset, tcx)?,
 871                         Scalar::from_int(NUM_CPUS, dword_size).into(),
 872                         dword_size,
 873                     )?;
 874             }
 875
 876             "TlsAlloc" => {
 877                 // This just creates a key; Windows does not natively support TLS destructors.
 878
 879                 // Create key and return it.
 880                 let key = this.machine.tls.create_tls_key(None) as u128;
 881
 882                 // Figure out how large a TLS key actually is. This is `c::DWORD`.
 883                 if dest.layout.size.bits() < 128
 884                         && key >= (1u128 << dest.layout.size.bits() as u128) {
 885                     return err!(OutOfTls);
 886                 }
 887                 this.write_scalar(Scalar::from_uint(key, dest.layout.size), dest)?;
 888             }
 889             "TlsGetValue" => {
 890                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 891                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 892                 this.write_scalar(ptr, dest)?;
 893             }
 894             "TlsSetValue" => {
 895                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 896                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 897                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 898
 899                 // Return success (`1`).
 900                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 901             }
 902             "GetStdHandle" => {
 903                 let which = this.read_scalar(args[0])?.to_i32()?;
 904                 // We just make this the identity function, so we know later in `WriteFile`
 905                 // which one it is.
 906                 this.write_scalar(Scalar::from_int(which, this.pointer_size()), dest)?;
 907             }
 908             "WriteFile" => {
 909                 let handle = this.read_scalar(args[0])?.to_isize(this)?;
 910                 let buf = this.read_scalar(args[1])?.not_undef()?;
 911                 let n = this.read_scalar(args[2])?.to_u32()?;
 912                 let written_place = this.deref_operand(args[3])?;
 913                 // Spec says to always write `0` first.
 914                 this.write_null(written_place.into())?;
 915                 let written = if handle == -11 || handle == -12 {
 916                     // stdout/stderr
 917                     use std::io::{self, Write};
 918
 919                     let buf_cont = this.memory().read_bytes(buf, Size::from_bytes(u64::from(n)))?;
 920                     let res = if handle == -11 {
 921                         io::stdout().write(buf_cont)
 922                     } else {
 923                         io::stderr().write(buf_cont)
 924                     };
 925                     res.ok().map(|n| n as u32)
 926                 } else {
 927                     eprintln!("Miri: Ignored output to handle {}", handle);
 928                     // Pretend it all went well.
 929                     Some(n)
 930                 };
 931                 // If there was no error, write back how much was written.
 932                 if let Some(n) = written {
 933                     this.write_scalar(Scalar::from_u32(n), written_place.into())?;
 934                 }
 935                 // Return whether this was a success.
 936                 this.write_scalar(
 937                     Scalar::from_int(if written.is_some() { 1 } else { 0 }, dest.layout.size),
 938                     dest,
 939                 )?;
 940             }
 941             "GetConsoleMode" => {
 942                 // Everything is a pipe.
 943                 this.write_null(dest)?;
 944             }
 945             "GetEnvironmentVariableW" => {
 946                 // This is not the env var you are looking for.
 947                 this.machine.last_error = 203; // ERROR_ENVVAR_NOT_FOUND
 948                 this.write_null(dest)?;
 949             }
 950             "GetCommandLineW" => {
 951                 this.write_scalar(Scalar::Ptr(this.machine.cmd_line.unwrap()), dest)?;
 952             }
 953             // The actual name of 'RtlGenRandom'
 954             "SystemFunction036" => {
 955                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 956                 let len = this.read_scalar(args[1])?.to_u32()?;
 957                 this.gen_random(len as usize, ptr)?;
 958                 this.write_scalar(Scalar::from_bool(true), dest)?;
 959             }
 960
 961             // We can't execute anything else.
 962             _ => {
 963                 return err!(Unimplemented(
 964                     format!("can't call foreign function: {}", link_name),
 965                 ));
 966             }
 967         }
 968
 969         this.goto_block(Some(ret))?;
 970         this.dump_place(*dest);
 971         Ok(())
 972     }
 973
 974     /// Evaluates the scalar at the specified path. Returns Some(val)
 975     /// if the path could be resolved, and None otherwise
 976     fn eval_path_scalar(&mut self, path: &[&str]) -> InterpResult<'tcx, Option<ScalarMaybeUndef<Tag>>> {
 977         let this = self.eval_context_mut();
 978         if let Ok(instance) = this.resolve_path(path) {
 979             let cid = GlobalId {
 980                 instance,
 981                 promoted: None,
 982             };
 983             let const_val = this.const_eval_raw(cid)?;
 984             let const_val = this.read_scalar(const_val.into())?;
 985             return Ok(Some(const_val));
 986         }
 987         return Ok(None);
 988     }
 989
 990     fn gen_random(
 991         &mut self,
 992         len: usize,
 993         dest: Scalar<Tag>,
 994     ) -> InterpResult<'tcx>  {
 995         if len == 0 {
 996             // Nothing to do
 997             return Ok(());
 998         }
 999         let this = self.eval_context_mut();
1000         let ptr = dest.to_ptr()?;
1001
1002         let data = match &mut this.memory_mut().extra.rng {
1003             Some(rng) => {
1004                 let mut rng = rng.borrow_mut();
1005                 let mut data = vec![0; len];
1006                 rng.fill_bytes(&mut data);
1007                 data
1008             }
1009             None => {
1010                 return err!(Unimplemented(
1011                     "miri does not support gathering system entropy in deterministic mode!
1012                     Use '-Zmiri-seed=<seed>' to enable random number generation.
1013                     WARNING: Miri does *not* generate cryptographically secure entropy -
1014                     do not use Miri to run any program that needs secure random number generation".to_owned(),
1015                 ));
1016             }
1017         };
1018         let tcx = &{this.tcx.tcx};
1019         this.memory_mut().get_mut(ptr.alloc_id)?
1020             .write_bytes(tcx, ptr, &data)
1021     }
1022 }