src/shims/foreign_items.rs

   1 use std::convert::TryInto;
   2
   3 use rustc_apfloat::Float;
   4 use rustc::ty::layout::{Align, LayoutOf, Size};
   5 use rustc::hir::def_id::DefId;
   6 use rustc::mir;
   7 use syntax::attr;
   8 use syntax::symbol::sym;
   9
  10 use crate::*;
  11
  12 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  13 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  14     /// Returns the minimum alignment for the target architecture for allocations of the given size.
  15     fn min_align(&self, size: u64, kind: MiriMemoryKind) -> Align {
  16         let this = self.eval_context_ref();
  17         // List taken from `libstd/sys_common/alloc.rs`.
  18         let min_align = match this.tcx.tcx.sess.target.target.arch.as_str() {
  19             "x86" | "arm" | "mips" | "powerpc" | "powerpc64" | "asmjs" | "wasm32" => 8,
  20             "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" => 16,
  21             arch => bug!("Unsupported target architecture: {}", arch),
  22         };
  23         // Windows always aligns, even small allocations.
  24         // Source: <https://support.microsoft.com/en-us/help/286470/how-to-use-pageheap-exe-in-windows-xp-windows-2000-and-windows-server>
  25         // But jemalloc does not, so for the C heap we only align if the allocation is sufficiently big.
  26         if kind == MiriMemoryKind::WinHeap || size >= min_align {
  27             return Align::from_bytes(min_align).unwrap();
  28         }
  29         // We have `size < min_align`. Round `size` *down* to the next power of two and use that.
  30         fn prev_power_of_two(x: u64) -> u64 {
  31             let next_pow2 = x.next_power_of_two();
  32             if next_pow2 == x {
  33                 // x *is* a power of two, just use that.
  34                 x
  35             } else {
  36                 // x is between two powers, so next = 2*prev.
  37                 next_pow2 / 2
  38             }
  39         }
  40         Align::from_bytes(prev_power_of_two(size)).unwrap()
  41     }
  42
  43     fn malloc(
  44         &mut self,
  45         size: u64,
  46         zero_init: bool,
  47         kind: MiriMemoryKind,
  48     ) -> Scalar<Tag> {
  49         let this = self.eval_context_mut();
  50         let tcx = &{this.tcx.tcx};
  51         if size == 0 {
  52             Scalar::from_int(0, this.pointer_size())
  53         } else {
  54             let align = this.min_align(size, kind);
  55             let ptr = this.memory_mut().allocate(Size::from_bytes(size), align, kind.into());
  56             if zero_init {
  57                 // We just allocated this, the access cannot fail
  58                 this.memory_mut()
  59                     .get_mut(ptr.alloc_id).unwrap()
  60                     .write_repeat(tcx, ptr, 0, Size::from_bytes(size)).unwrap();
  61             }
  62             Scalar::Ptr(ptr)
  63         }
  64     }
  65
  66     fn free(
  67         &mut self,
  68         ptr: Scalar<Tag>,
  69         kind: MiriMemoryKind,
  70     ) -> InterpResult<'tcx> {
  71         let this = self.eval_context_mut();
  72         if !this.is_null(ptr)? {
  73             let ptr = this.force_ptr(ptr)?;
  74             this.memory_mut().deallocate(
  75                 ptr,
  76                 None,
  77                 kind.into(),
  78             )?;
  79         }
  80         Ok(())
  81     }
  82
  83     fn realloc(
  84         &mut self,
  85         old_ptr: Scalar<Tag>,
  86         new_size: u64,
  87         kind: MiriMemoryKind,
  88     ) -> InterpResult<'tcx, Scalar<Tag>> {
  89         let this = self.eval_context_mut();
  90         let new_align = this.min_align(new_size, kind);
  91         if this.is_null(old_ptr)? {
  92             if new_size == 0 {
  93                 Ok(Scalar::from_int(0, this.pointer_size()))
  94             } else {
  95                 let new_ptr = this.memory_mut().allocate(
  96                     Size::from_bytes(new_size),
  97                     new_align,
  98                     kind.into()
  99                 );
 100                 Ok(Scalar::Ptr(new_ptr))
 101             }
 102         } else {
 103             let old_ptr = this.force_ptr(old_ptr)?;
 104             let memory = this.memory_mut();
 105             if new_size == 0 {
 106                 memory.deallocate(
 107                     old_ptr,
 108                     None,
 109                     kind.into(),
 110                 )?;
 111                 Ok(Scalar::from_int(0, this.pointer_size()))
 112             } else {
 113                 let new_ptr = memory.reallocate(
 114                     old_ptr,
 115                     None,
 116                     Size::from_bytes(new_size),
 117                     new_align,
 118                     kind.into(),
 119                 )?;
 120                 Ok(Scalar::Ptr(new_ptr))
 121             }
 122         }
 123     }
 124
 125     /// Emulates calling a foreign item, failing if the item is not supported.
 126     /// This function will handle `goto_block` if needed.
 127     fn emulate_foreign_item(
 128         &mut self,
 129         def_id: DefId,
 130         args: &[OpTy<'tcx, Tag>],
 131         dest: Option<PlaceTy<'tcx, Tag>>,
 132         ret: Option<mir::BasicBlock>,
 133     ) -> InterpResult<'tcx> {
 134         let this = self.eval_context_mut();
 135         let attrs = this.tcx.get_attrs(def_id);
 136         let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
 137             Some(name) => name.as_str(),
 138             None => this.tcx.item_name(def_id).as_str(),
 139         };
 140         // Strip linker suffixes (seen on 32-bit macOS).
 141         let link_name = link_name.get().trim_end_matches("$UNIX2003");
 142         let tcx = &{this.tcx.tcx};
 143
 144         // First: functions that diverge.
 145         match link_name {
 146             "__rust_start_panic" | "panic_impl" => {
 147                 throw_unsup_format!("the evaluated program panicked");
 148             }
 149             "exit" | "ExitProcess" => {
 150                 // it's really u32 for ExitProcess, but we have to put it into the `Exit` error variant anyway
 151                 let code = this.read_scalar(args[0])?.to_i32()?;
 152                 return Err(InterpError::Exit(code).into());
 153             }
 154             _ => if dest.is_none() {
 155                 throw_unsup_format!("can't call (diverging) foreign function: {}", link_name);
 156             }
 157         }
 158
 159         // Next: functions that assume a ret and dest.
 160         let dest = dest.expect("we already checked for a dest");
 161         let ret = ret.expect("dest is `Some` but ret is `None`");
 162         match link_name {
 163             "malloc" => {
 164                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 165                 let res = this.malloc(size, /*zero_init:*/ false, MiriMemoryKind::C);
 166                 this.write_scalar(res, dest)?;
 167             }
 168             "calloc" => {
 169                 let items = this.read_scalar(args[0])?.to_usize(this)?;
 170                 let len = this.read_scalar(args[1])?.to_usize(this)?;
 171                 let size = items.checked_mul(len).ok_or_else(|| err_panic!(Overflow(mir::BinOp::Mul)))?;
 172                 let res = this.malloc(size, /*zero_init:*/ true, MiriMemoryKind::C);
 173                 this.write_scalar(res, dest)?;
 174             }
 175             "posix_memalign" => {
 176                 let ret = this.deref_operand(args[0])?;
 177                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 178                 let size = this.read_scalar(args[2])?.to_usize(this)?;
 179                 // Align must be power of 2, and also at least ptr-sized (POSIX rules).
 180                 if !align.is_power_of_two() {
 181                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 182                 }
 183                 if align < this.pointer_size().bytes() {
 184                     throw_ub_format!(
 185                         "posix_memalign: alignment must be at least the size of a pointer, but is {}",
 186                         align,
 187                     );
 188                 }
 189
 190                 if size == 0 {
 191                     this.write_null(ret.into())?;
 192                 } else {
 193                     let ptr = this.memory_mut().allocate(
 194                         Size::from_bytes(size),
 195                         Align::from_bytes(align).unwrap(),
 196                         MiriMemoryKind::C.into()
 197                     );
 198                     this.write_scalar(Scalar::Ptr(ptr), ret.into())?;
 199                 }
 200                 this.write_null(dest)?;
 201             }
 202             "free" => {
 203                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 204                 this.free(ptr, MiriMemoryKind::C)?;
 205             }
 206             "realloc" => {
 207                 let old_ptr = this.read_scalar(args[0])?.not_undef()?;
 208                 let new_size = this.read_scalar(args[1])?.to_usize(this)?;
 209                 let res = this.realloc(old_ptr, new_size, MiriMemoryKind::C)?;
 210                 this.write_scalar(res, dest)?;
 211             }
 212
 213             "__rust_alloc" => {
 214                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 215                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 216                 if size == 0 {
 217                     throw_unsup!(HeapAllocZeroBytes);
 218                 }
 219                 if !align.is_power_of_two() {
 220                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 221                 }
 222                 let ptr = this.memory_mut()
 223                     .allocate(
 224                         Size::from_bytes(size),
 225                         Align::from_bytes(align).unwrap(),
 226                         MiriMemoryKind::Rust.into()
 227                     );
 228                 this.write_scalar(Scalar::Ptr(ptr), dest)?;
 229             }
 230             "__rust_alloc_zeroed" => {
 231                 let size = this.read_scalar(args[0])?.to_usize(this)?;
 232                 let align = this.read_scalar(args[1])?.to_usize(this)?;
 233                 if size == 0 {
 234                     throw_unsup!(HeapAllocZeroBytes);
 235                 }
 236                 if !align.is_power_of_two() {
 237                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 238                 }
 239                 let ptr = this.memory_mut()
 240                     .allocate(
 241                         Size::from_bytes(size),
 242                         Align::from_bytes(align).unwrap(),
 243                         MiriMemoryKind::Rust.into()
 244                     );
 245                 // We just allocated this, the access cannot fail
 246                 this.memory_mut()
 247                     .get_mut(ptr.alloc_id).unwrap()
 248                     .write_repeat(tcx, ptr, 0, Size::from_bytes(size)).unwrap();
 249                 this.write_scalar(Scalar::Ptr(ptr), dest)?;
 250             }
 251             "__rust_dealloc" => {
 252                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 253                 let old_size = this.read_scalar(args[1])?.to_usize(this)?;
 254                 let align = this.read_scalar(args[2])?.to_usize(this)?;
 255                 if old_size == 0 {
 256                     throw_unsup!(HeapAllocZeroBytes);
 257                 }
 258                 if !align.is_power_of_two() {
 259                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 260                 }
 261                 let ptr = this.force_ptr(ptr)?;
 262                 this.memory_mut().deallocate(
 263                     ptr,
 264                     Some((Size::from_bytes(old_size), Align::from_bytes(align).unwrap())),
 265                     MiriMemoryKind::Rust.into(),
 266                 )?;
 267             }
 268             "__rust_realloc" => {
 269                 let ptr = this.read_scalar(args[0])?.to_ptr()?;
 270                 let old_size = this.read_scalar(args[1])?.to_usize(this)?;
 271                 let align = this.read_scalar(args[2])?.to_usize(this)?;
 272                 let new_size = this.read_scalar(args[3])?.to_usize(this)?;
 273                 if old_size == 0 || new_size == 0 {
 274                     throw_unsup!(HeapAllocZeroBytes);
 275                 }
 276                 if !align.is_power_of_two() {
 277                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 278                 }
 279                 let align = Align::from_bytes(align).unwrap();
 280                 let new_ptr = this.memory_mut().reallocate(
 281                     ptr,
 282                     Some((Size::from_bytes(old_size), align)),
 283                     Size::from_bytes(new_size),
 284                     align,
 285                     MiriMemoryKind::Rust.into(),
 286                 )?;
 287                 this.write_scalar(Scalar::Ptr(new_ptr), dest)?;
 288             }
 289
 290             "syscall" => {
 291                 let sys_getrandom = this.eval_path_scalar(&["libc", "SYS_getrandom"])?
 292                     .expect("Failed to get libc::SYS_getrandom")
 293                     .to_usize(this)?;
 294
 295                 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
 296                 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
 297                 match this.read_scalar(args[0])?.to_usize(this)? {
 298                     id if id == sys_getrandom => {
 299                         // The first argument is the syscall id,
 300                         // so skip over it.
 301                         linux_getrandom(this, &args[1..], dest)?;
 302                     }
 303                     id => {
 304                         throw_unsup_format!("miri does not support syscall ID {}", id)
 305                     }
 306                 }
 307             }
 308
 309             "getrandom" => {
 310                 linux_getrandom(this, args, dest)?;
 311             }
 312
 313             "dlsym" => {
 314                 let _handle = this.read_scalar(args[0])?;
 315                 let symbol = this.read_scalar(args[1])?.not_undef()?;
 316                 let symbol_name = this.memory().read_c_str(symbol)?;
 317                 let err = format!("bad c unicode symbol: {:?}", symbol_name);
 318                 let symbol_name = ::std::str::from_utf8(symbol_name).unwrap_or(&err);
 319                 if let Some(dlsym) = Dlsym::from_str(symbol_name)? {
 320                     let ptr = this.memory_mut().create_fn_alloc(FnVal::Other(dlsym));
 321                     this.write_scalar(Scalar::from(ptr), dest)?;
 322                 } else {
 323                     this.write_null(dest)?;
 324                 }
 325             }
 326
 327             "__rust_maybe_catch_panic" => {
 328                 // fn __rust_maybe_catch_panic(
 329                 //     f: fn(*mut u8),
 330                 //     data: *mut u8,
 331                 //     data_ptr: *mut usize,
 332                 //     vtable_ptr: *mut usize,
 333                 // ) -> u32
 334                 // We abort on panic, so not much is going on here, but we still have to call the closure.
 335                 let f = this.read_scalar(args[0])?.not_undef()?;
 336                 let data = this.read_scalar(args[1])?.not_undef()?;
 337                 let f_instance = this.memory().get_fn(f)?.as_instance()?;
 338                 this.write_null(dest)?;
 339                 trace!("__rust_maybe_catch_panic: {:?}", f_instance);
 340
 341                 // Now we make a function call.
 342                 // TODO: consider making this reusable? `InterpCx::step` does something similar
 343                 // for the TLS destructors, and of course `eval_main`.
 344                 let mir = this.load_mir(f_instance.def)?;
 345                 let ret_place = MPlaceTy::dangling(this.layout_of(this.tcx.mk_unit())?, this).into();
 346                 this.push_stack_frame(
 347                     f_instance,
 348                     mir.span,
 349                     mir,
 350                     Some(ret_place),
 351                     // Directly return to caller.
 352                     StackPopCleanup::Goto(Some(ret)),
 353                 )?;
 354                 let mut args = this.frame().body.args_iter();
 355
 356                 let arg_local = args.next()
 357                     .expect("Argument to __rust_maybe_catch_panic does not take enough arguments.");
 358                 let arg_dest = this.local_place(arg_local)?;
 359                 this.write_scalar(data, arg_dest)?;
 360
 361                 assert!(args.next().is_none(), "__rust_maybe_catch_panic argument has more arguments than expected");
 362
 363                 // We ourselves will return `0`, eventually (because we will not return if we paniced).
 364                 this.write_null(dest)?;
 365
 366                 // Don't fall through, we do *not* want to `goto_block`!
 367                 return Ok(());
 368             }
 369
 370             "memcmp" => {
 371                 let left = this.read_scalar(args[0])?.not_undef()?;
 372                 let right = this.read_scalar(args[1])?.not_undef()?;
 373                 let n = Size::from_bytes(this.read_scalar(args[2])?.to_usize(this)?);
 374
 375                 let result = {
 376                     let left_bytes = this.memory().read_bytes(left, n)?;
 377                     let right_bytes = this.memory().read_bytes(right, n)?;
 378
 379                     use std::cmp::Ordering::*;
 380                     match left_bytes.cmp(right_bytes) {
 381                         Less => -1i32,
 382                         Equal => 0,
 383                         Greater => 1,
 384                     }
 385                 };
 386
 387                 this.write_scalar(
 388                     Scalar::from_int(result, Size::from_bits(32)),
 389                     dest,
 390                 )?;
 391             }
 392
 393             "memrchr" => {
 394                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 395                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 396                 let num = this.read_scalar(args[2])?.to_usize(this)?;
 397                 if let Some(idx) = this.memory().read_bytes(ptr, Size::from_bytes(num))?
 398                     .iter().rev().position(|&c| c == val)
 399                 {
 400                     let new_ptr = ptr.ptr_offset(Size::from_bytes(num - idx as u64 - 1), this)?;
 401                     this.write_scalar(new_ptr, dest)?;
 402                 } else {
 403                     this.write_null(dest)?;
 404                 }
 405             }
 406
 407             "memchr" => {
 408                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 409                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 410                 let num = this.read_scalar(args[2])?.to_usize(this)?;
 411                 let idx = this
 412                     .memory()
 413                     .read_bytes(ptr, Size::from_bytes(num))?
 414                     .iter()
 415                     .position(|&c| c == val);
 416                 if let Some(idx) = idx {
 417                     let new_ptr = ptr.ptr_offset(Size::from_bytes(idx as u64), this)?;
 418                     this.write_scalar(new_ptr, dest)?;
 419                 } else {
 420                     this.write_null(dest)?;
 421                 }
 422             }
 423
 424             "getenv" => {
 425                 let result = {
 426                     let name_ptr = this.read_scalar(args[0])?.not_undef()?;
 427                     let name = this.memory().read_c_str(name_ptr)?;
 428                     match this.machine.env_vars.get(name) {
 429                         Some(&var) => Scalar::Ptr(var),
 430                         None => Scalar::ptr_null(&*this.tcx),
 431                     }
 432                 };
 433                 this.write_scalar(result, dest)?;
 434             }
 435
 436             "unsetenv" => {
 437                 let mut success = None;
 438                 {
 439                     let name_ptr = this.read_scalar(args[0])?.not_undef()?;
 440                     if !this.is_null(name_ptr)? {
 441                         let name = this.memory().read_c_str(name_ptr)?.to_owned();
 442                         if !name.is_empty() && !name.contains(&b'=') {
 443                             success = Some(this.machine.env_vars.remove(&name));
 444                         }
 445                     }
 446                 }
 447                 if let Some(old) = success {
 448                     if let Some(var) = old {
 449                         this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
 450                     }
 451                     this.write_null(dest)?;
 452                 } else {
 453                     this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 454                 }
 455             }
 456
 457             "setenv" => {
 458                 let mut new = None;
 459                 {
 460                     let name_ptr = this.read_scalar(args[0])?.not_undef()?;
 461                     let value_ptr = this.read_scalar(args[1])?.not_undef()?;
 462                     let value = this.memory().read_c_str(value_ptr)?;
 463                     if !this.is_null(name_ptr)? {
 464                         let name = this.memory().read_c_str(name_ptr)?;
 465                         if !name.is_empty() && !name.contains(&b'=') {
 466                             new = Some((name.to_owned(), value.to_owned()));
 467                         }
 468                     }
 469                 }
 470                 if let Some((name, value)) = new {
 471                     // `+1` for the null terminator.
 472                     let value_copy = this.memory_mut().allocate(
 473                         Size::from_bytes((value.len() + 1) as u64),
 474                         Align::from_bytes(1).unwrap(),
 475                         MiriMemoryKind::Env.into(),
 476                     );
 477                     // We just allocated these, so the write cannot fail.
 478                     let alloc = this.memory_mut().get_mut(value_copy.alloc_id).unwrap();
 479                     alloc.write_bytes(tcx, value_copy, &value).unwrap();
 480                     let trailing_zero_ptr = value_copy.offset(
 481                         Size::from_bytes(value.len() as u64),
 482                         tcx,
 483                     ).unwrap();
 484                     alloc.write_bytes(tcx, trailing_zero_ptr, &[0]).unwrap();
 485
 486                     if let Some(var) = this.machine.env_vars.insert(
 487                         name.to_owned(),
 488                         value_copy,
 489                     )
 490                     {
 491                         this.memory_mut().deallocate(var, None, MiriMemoryKind::Env.into())?;
 492                     }
 493                     this.write_null(dest)?;
 494                 } else {
 495                     this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 496                 }
 497             }
 498
 499             "write" => {
 500                 let fd = this.read_scalar(args[0])?.to_i32()?;
 501                 let buf = this.read_scalar(args[1])?.not_undef()?;
 502                 let n = this.read_scalar(args[2])?.to_usize(&*this.tcx)?;
 503                 trace!("Called write({:?}, {:?}, {:?})", fd, buf, n);
 504                 let result = if fd == 1 || fd == 2 {
 505                     // stdout/stderr
 506                     use std::io::{self, Write};
 507
 508                     let buf_cont = this.memory().read_bytes(buf, Size::from_bytes(n))?;
 509                     // We need to flush to make sure this actually appears on the screen
 510                     let res = if fd == 1 {
 511                         // Stdout is buffered, flush to make sure it appears on the screen.
 512                         // This is the write() syscall of the interpreted program, we want it
 513                         // to correspond to a write() syscall on the host -- there is no good
 514                         // in adding extra buffering here.
 515                         let res = io::stdout().write(buf_cont);
 516                         io::stdout().flush().unwrap();
 517                         res
 518                     } else {
 519                         // No need to flush, stderr is not buffered.
 520                         io::stderr().write(buf_cont)
 521                     };
 522                     match res {
 523                         Ok(n) => n as i64,
 524                         Err(_) => -1,
 525                     }
 526                 } else {
 527                     eprintln!("Miri: Ignored output to FD {}", fd);
 528                     // Pretend it all went well.
 529                     n as i64
 530                 };
 531                 // Now, `result` is the value we return back to the program.
 532                 this.write_scalar(
 533                     Scalar::from_int(result, dest.layout.size),
 534                     dest,
 535                 )?;
 536             }
 537
 538             "strlen" => {
 539                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 540                 let n = this.memory().read_c_str(ptr)?.len();
 541                 this.write_scalar(Scalar::from_uint(n as u64, dest.layout.size), dest)?;
 542             }
 543
 544             // math functions
 545
 546             "cbrtf" | "coshf" | "sinhf" |"tanf" => {
 547                 // FIXME: Using host floats.
 548                 let f = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 549                 let f = match link_name {
 550                     "cbrtf" => f.cbrt(),
 551                     "coshf" => f.cosh(),
 552                     "sinhf" => f.sinh(),
 553                     "tanf" => f.tan(),
 554                     _ => bug!(),
 555                 };
 556                 this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
 557             }
 558             // underscore case for windows
 559             "_hypotf" | "hypotf" | "atan2f" => {
 560                 // FIXME: Using host floats.
 561                 let f1 = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 562                 let f2 = f32::from_bits(this.read_scalar(args[1])?.to_u32()?);
 563                 let n = match link_name {
 564                     "_hypotf" | "hypotf" => f1.hypot(f2),
 565                     "atan2f" => f1.atan2(f2),
 566                     _ => bug!(),
 567                 };
 568                 this.write_scalar(Scalar::from_u32(n.to_bits()), dest)?;
 569             }
 570
 571             "cbrt" | "cosh" | "sinh" | "tan" => {
 572                 // FIXME: Using host floats.
 573                 let f = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 574                 let f = match link_name {
 575                     "cbrt" => f.cbrt(),
 576                     "cosh" => f.cosh(),
 577                     "sinh" => f.sinh(),
 578                     "tan" => f.tan(),
 579                     _ => bug!(),
 580                 };
 581                 this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
 582             }
 583             // underscore case for windows, here and below
 584             // (see https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/floating-point-primitives?view=vs-2019)
 585             "_hypot" | "hypot" | "atan2" => {
 586                 // FIXME: Using host floats.
 587                 let f1 = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 588                 let f2 = f64::from_bits(this.read_scalar(args[1])?.to_u64()?);
 589                 let n = match link_name {
 590                     "_hypot" | "hypot" => f1.hypot(f2),
 591                     "atan2" => f1.atan2(f2),
 592                     _ => bug!(),
 593                 };
 594                 this.write_scalar(Scalar::from_u64(n.to_bits()), dest)?;
 595             }
 596             // For radix-2 (binary) systems, `ldexp` and `scalbn` are the same.
 597             "_ldexp" | "ldexp" | "scalbn" => {
 598                 let x = this.read_scalar(args[0])?.to_f64()?;
 599                 let exp = this.read_scalar(args[1])?.to_i32()?;
 600                 // Saturating cast to i16. Even those are outside the valid exponent range to
 601                 // `scalbn` below will to its over/underflow handling.
 602                 let exp = if exp > i16::max_value() as i32 {
 603                     i16::max_value()
 604                 } else if exp < i16::min_value() as i32 {
 605                     i16::min_value()
 606                 } else {
 607                     exp.try_into().unwrap()
 608                 };
 609                 let res = x.scalbn(exp);
 610                 this.write_scalar(Scalar::from_f64(res), dest)?;
 611             }
 612
 613             // Some things needed for `sys::thread` initialization to go through.
 614             "signal" | "sigaction" | "sigaltstack" => {
 615                 this.write_scalar(Scalar::from_int(0, dest.layout.size), dest)?;
 616             }
 617
 618             "sysconf" => {
 619                 let name = this.read_scalar(args[0])?.to_i32()?;
 620
 621                 trace!("sysconf() called with name {}", name);
 622                 // TODO: Cache the sysconf integers via Miri's global cache.
 623                 let paths = &[
 624                     (&["libc", "_SC_PAGESIZE"], Scalar::from_int(PAGE_SIZE, dest.layout.size)),
 625                     (&["libc", "_SC_GETPW_R_SIZE_MAX"], Scalar::from_int(-1, dest.layout.size)),
 626                     (&["libc", "_SC_NPROCESSORS_ONLN"], Scalar::from_int(NUM_CPUS, dest.layout.size)),
 627                 ];
 628                 let mut result = None;
 629                 for &(path, path_value) in paths {
 630                     if let Some(val) = this.eval_path_scalar(path)? {
 631                         let val = val.to_i32()?;
 632                         if val == name {
 633                             result = Some(path_value);
 634                             break;
 635                         }
 636
 637                     }
 638                 }
 639                 if let Some(result) = result {
 640                     this.write_scalar(result, dest)?;
 641                 } else {
 642                     throw_unsup_format!("Unimplemented sysconf name: {}", name)
 643                 }
 644             }
 645
 646             "sched_getaffinity" => {
 647                 // Return an error; `num_cpus` then falls back to `sysconf`.
 648                 this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 649             }
 650
 651             "isatty" => {
 652                 this.write_null(dest)?;
 653             }
 654
 655             // Hook pthread calls that go to the thread-local storage memory subsystem.
 656             "pthread_key_create" => {
 657                 let key_ptr = this.read_scalar(args[0])?.not_undef()?;
 658
 659                 // Extract the function type out of the signature (that seems easier than constructing it ourselves).
 660                 let dtor = match this.test_null(this.read_scalar(args[1])?.not_undef()?)? {
 661                     Some(dtor_ptr) => Some(this.memory().get_fn(dtor_ptr)?.as_instance()?),
 662                     None => None,
 663                 };
 664
 665                 // Figure out how large a pthread TLS key actually is.
 666                 // This is `libc::pthread_key_t`.
 667                 let key_type = args[0].layout.ty
 668                     .builtin_deref(true)
 669                     .ok_or_else(|| err_ub_format!(
 670                         "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
 671                     ))?
 672                     .ty;
 673                 let key_layout = this.layout_of(key_type)?;
 674
 675                 // Create key and write it into the memory where `key_ptr` wants it.
 676                 let key = this.machine.tls.create_tls_key(dtor) as u128;
 677                 if key_layout.size.bits() < 128 && key >= (1u128 << key_layout.size.bits() as u128) {
 678                     throw_unsup!(OutOfTls);
 679                 }
 680
 681                 let key_ptr = this.memory().check_ptr_access(key_ptr, key_layout.size, key_layout.align.abi)?
 682                     .expect("cannot be a ZST");
 683                 this.memory_mut().get_mut(key_ptr.alloc_id)?.write_scalar(
 684                     tcx,
 685                     key_ptr,
 686                     Scalar::from_uint(key, key_layout.size).into(),
 687                     key_layout.size,
 688                 )?;
 689
 690                 // Return success (`0`).
 691                 this.write_null(dest)?;
 692             }
 693             "pthread_key_delete" => {
 694                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 695                 this.machine.tls.delete_tls_key(key)?;
 696                 // Return success (0)
 697                 this.write_null(dest)?;
 698             }
 699             "pthread_getspecific" => {
 700                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 701                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 702                 this.write_scalar(ptr, dest)?;
 703             }
 704             "pthread_setspecific" => {
 705                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 706                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 707                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 708
 709                 // Return success (`0`).
 710                 this.write_null(dest)?;
 711             }
 712
 713             // Stack size/address stuff.
 714             "pthread_attr_init" | "pthread_attr_destroy" | "pthread_self" |
 715             "pthread_attr_setstacksize" => {
 716                 this.write_null(dest)?;
 717             }
 718             "pthread_attr_getstack" => {
 719                 let addr_place = this.deref_operand(args[1])?;
 720                 let size_place = this.deref_operand(args[2])?;
 721
 722                 this.write_scalar(
 723                     Scalar::from_uint(STACK_ADDR, addr_place.layout.size),
 724                     addr_place.into(),
 725                 )?;
 726                 this.write_scalar(
 727                     Scalar::from_uint(STACK_SIZE, size_place.layout.size),
 728                     size_place.into(),
 729                 )?;
 730
 731                 // Return success (`0`).
 732                 this.write_null(dest)?;
 733             }
 734
 735             // We don't support threading. (Also for Windows.)
 736             "pthread_create" | "CreateThread" => {
 737                 throw_unsup_format!("Miri does not support threading");
 738             }
 739
 740             // Stub out calls for condvar, mutex and rwlock, to just return `0`.
 741             "pthread_mutexattr_init" | "pthread_mutexattr_settype" | "pthread_mutex_init" |
 742             "pthread_mutexattr_destroy" | "pthread_mutex_lock" | "pthread_mutex_unlock" |
 743             "pthread_mutex_destroy" | "pthread_rwlock_rdlock" | "pthread_rwlock_unlock" |
 744             "pthread_rwlock_wrlock" | "pthread_rwlock_destroy" | "pthread_condattr_init" |
 745             "pthread_condattr_setclock" | "pthread_cond_init" | "pthread_condattr_destroy" |
 746             "pthread_cond_destroy" => {
 747                 this.write_null(dest)?;
 748             }
 749
 750             // We don't support fork so we don't have to do anything for atfork.
 751             "pthread_atfork" => {
 752                 this.write_null(dest)?;
 753             }
 754
 755             "mmap" => {
 756                 // 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.
 757                 let addr = this.read_scalar(args[0])?.not_undef()?;
 758                 this.write_scalar(addr, dest)?;
 759             }
 760             "mprotect" => {
 761                 this.write_null(dest)?;
 762             }
 763
 764             // macOS API stubs.
 765             "pthread_attr_get_np" | "pthread_getattr_np" => {
 766                 this.write_null(dest)?;
 767             }
 768             "pthread_get_stackaddr_np" => {
 769                 let stack_addr = Scalar::from_uint(STACK_ADDR, dest.layout.size);
 770                 this.write_scalar(stack_addr, dest)?;
 771             }
 772             "pthread_get_stacksize_np" => {
 773                 let stack_size = Scalar::from_uint(STACK_SIZE, dest.layout.size);
 774                 this.write_scalar(stack_size, dest)?;
 775             }
 776             "_tlv_atexit" => {
 777                 // FIXME: register the destructor.
 778             },
 779             "_NSGetArgc" => {
 780                 this.write_scalar(Scalar::Ptr(this.machine.argc.unwrap()), dest)?;
 781             },
 782             "_NSGetArgv" => {
 783                 this.write_scalar(Scalar::Ptr(this.machine.argv.unwrap()), dest)?;
 784             },
 785             "SecRandomCopyBytes" => {
 786                 let len = this.read_scalar(args[1])?.to_usize(this)?;
 787                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 788                 this.gen_random(ptr, len as usize)?;
 789                 this.write_null(dest)?;
 790             }
 791
 792             // Windows API stubs.
 793             // HANDLE = isize
 794             // DWORD = ULONG = u32
 795             // BOOL = i32
 796             "GetProcessHeap" => {
 797                 // Just fake a HANDLE
 798                 this.write_scalar(Scalar::from_int(1, this.pointer_size()), dest)?;
 799             }
 800             "HeapAlloc" => {
 801                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 802                 let flags = this.read_scalar(args[1])?.to_u32()?;
 803                 let size = this.read_scalar(args[2])?.to_usize(this)?;
 804                 let zero_init = (flags & 0x00000008) != 0; // HEAP_ZERO_MEMORY
 805                 let res = this.malloc(size, zero_init, MiriMemoryKind::WinHeap);
 806                 this.write_scalar(res, dest)?;
 807             }
 808             "HeapFree" => {
 809                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 810                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 811                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 812                 this.free(ptr, MiriMemoryKind::WinHeap)?;
 813                 this.write_scalar(Scalar::from_int(1, Size::from_bytes(4)), dest)?;
 814             }
 815             "HeapReAlloc" => {
 816                 let _handle = this.read_scalar(args[0])?.to_isize(this)?;
 817                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 818                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 819                 let size = this.read_scalar(args[3])?.to_usize(this)?;
 820                 let res = this.realloc(ptr, size, MiriMemoryKind::WinHeap)?;
 821                 this.write_scalar(res, dest)?;
 822             }
 823
 824             "SetLastError" => {
 825                 let err = this.read_scalar(args[0])?.to_u32()?;
 826                 this.machine.last_error = err;
 827             }
 828             "GetLastError" => {
 829                 this.write_scalar(Scalar::from_u32(this.machine.last_error), dest)?;
 830             }
 831
 832             "AddVectoredExceptionHandler" => {
 833                 // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
 834                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 835             },
 836             "InitializeCriticalSection" |
 837             "EnterCriticalSection" |
 838             "LeaveCriticalSection" |
 839             "DeleteCriticalSection" => {
 840                 // Nothing to do, not even a return value.
 841             },
 842             "GetModuleHandleW" |
 843             "GetProcAddress" |
 844             "TryEnterCriticalSection" |
 845             "GetConsoleScreenBufferInfo" |
 846             "SetConsoleTextAttribute" => {
 847                 // Pretend these do not exist / nothing happened, by returning zero.
 848                 this.write_null(dest)?;
 849             },
 850             "GetSystemInfo" => {
 851                 let system_info = this.deref_operand(args[0])?;
 852                 let system_info_ptr = this.check_mplace_access(system_info, None)?
 853                     .expect("cannot be a ZST");
 854                 // Initialize with `0`.
 855                 this.memory_mut().get_mut(system_info_ptr.alloc_id)?
 856                     .write_repeat(tcx, system_info_ptr, 0, system_info.layout.size)?;
 857                 // Set number of processors.
 858                 let dword_size = Size::from_bytes(4);
 859                 let offset = 2*dword_size + 3*tcx.pointer_size();
 860                 this.memory_mut().get_mut(system_info_ptr.alloc_id)?
 861                     .write_scalar(
 862                         tcx,
 863                         system_info_ptr.offset(offset, tcx)?,
 864                         Scalar::from_int(NUM_CPUS, dword_size).into(),
 865                         dword_size,
 866                     )?;
 867             }
 868
 869             "TlsAlloc" => {
 870                 // This just creates a key; Windows does not natively support TLS destructors.
 871
 872                 // Create key and return it.
 873                 let key = this.machine.tls.create_tls_key(None) as u128;
 874
 875                 // Figure out how large a TLS key actually is. This is `c::DWORD`.
 876                 if dest.layout.size.bits() < 128
 877                         && key >= (1u128 << dest.layout.size.bits() as u128) {
 878                     throw_unsup!(OutOfTls);
 879                 }
 880                 this.write_scalar(Scalar::from_uint(key, dest.layout.size), dest)?;
 881             }
 882             "TlsGetValue" => {
 883                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 884                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 885                 this.write_scalar(ptr, dest)?;
 886             }
 887             "TlsSetValue" => {
 888                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 889                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 890                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 891
 892                 // Return success (`1`).
 893                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 894             }
 895             "GetStdHandle" => {
 896                 let which = this.read_scalar(args[0])?.to_i32()?;
 897                 // We just make this the identity function, so we know later in `WriteFile`
 898                 // which one it is.
 899                 this.write_scalar(Scalar::from_int(which, this.pointer_size()), dest)?;
 900             }
 901             "WriteFile" => {
 902                 let handle = this.read_scalar(args[0])?.to_isize(this)?;
 903                 let buf = this.read_scalar(args[1])?.not_undef()?;
 904                 let n = this.read_scalar(args[2])?.to_u32()?;
 905                 let written_place = this.deref_operand(args[3])?;
 906                 // Spec says to always write `0` first.
 907                 this.write_null(written_place.into())?;
 908                 let written = if handle == -11 || handle == -12 {
 909                     // stdout/stderr
 910                     use std::io::{self, Write};
 911
 912                     let buf_cont = this.memory().read_bytes(buf, Size::from_bytes(u64::from(n)))?;
 913                     let res = if handle == -11 {
 914                         io::stdout().write(buf_cont)
 915                     } else {
 916                         io::stderr().write(buf_cont)
 917                     };
 918                     res.ok().map(|n| n as u32)
 919                 } else {
 920                     eprintln!("Miri: Ignored output to handle {}", handle);
 921                     // Pretend it all went well.
 922                     Some(n)
 923                 };
 924                 // If there was no error, write back how much was written.
 925                 if let Some(n) = written {
 926                     this.write_scalar(Scalar::from_u32(n), written_place.into())?;
 927                 }
 928                 // Return whether this was a success.
 929                 this.write_scalar(
 930                     Scalar::from_int(if written.is_some() { 1 } else { 0 }, dest.layout.size),
 931                     dest,
 932                 )?;
 933             }
 934             "GetConsoleMode" => {
 935                 // Everything is a pipe.
 936                 this.write_null(dest)?;
 937             }
 938             "GetEnvironmentVariableW" => {
 939                 // This is not the env var you are looking for.
 940                 this.machine.last_error = 203; // ERROR_ENVVAR_NOT_FOUND
 941                 this.write_null(dest)?;
 942             }
 943             "GetCommandLineW" => {
 944                 this.write_scalar(Scalar::Ptr(this.machine.cmd_line.unwrap()), dest)?;
 945             }
 946             // The actual name of 'RtlGenRandom'
 947             "SystemFunction036" => {
 948                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 949                 let len = this.read_scalar(args[1])?.to_u32()?;
 950                 this.gen_random(ptr, len as usize)?;
 951                 this.write_scalar(Scalar::from_bool(true), dest)?;
 952             }
 953
 954             // We can't execute anything else.
 955             _ => {
 956                 throw_unsup_format!("can't call foreign function: {}", link_name)
 957             }
 958         }
 959
 960         this.goto_block(Some(ret))?;
 961         this.dump_place(*dest);
 962         Ok(())
 963     }
 964
 965     /// Evaluates the scalar at the specified path. Returns Some(val)
 966     /// if the path could be resolved, and None otherwise
 967     fn eval_path_scalar(&mut self, path: &[&str]) -> InterpResult<'tcx, Option<ScalarMaybeUndef<Tag>>> {
 968         let this = self.eval_context_mut();
 969         if let Ok(instance) = this.resolve_path(path) {
 970             let cid = GlobalId {
 971                 instance,
 972                 promoted: None,
 973             };
 974             let const_val = this.const_eval_raw(cid)?;
 975             let const_val = this.read_scalar(const_val.into())?;
 976             return Ok(Some(const_val));
 977         }
 978         return Ok(None);
 979     }
 980 }
 981
 982 // Shims the linux 'getrandom()' syscall.
 983 fn linux_getrandom<'tcx>(
 984     this: &mut MiriEvalContext<'_, 'tcx>,
 985     args: &[OpTy<'tcx, Tag>],
 986     dest: PlaceTy<'tcx, Tag>,
 987 ) -> InterpResult<'tcx> {
 988     let ptr = this.read_scalar(args[0])?.not_undef()?;
 989     let len = this.read_scalar(args[1])?.to_usize(this)?;
 990
 991     // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
 992     // neither of which have any effect on our current PRNG.
 993     let _flags = this.read_scalar(args[2])?.to_i32()?;
 994
 995     this.gen_random(ptr, len as usize)?;
 996     this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
 997     Ok(())
 998 }