src/shims/foreign_items.rs

   1 use std::{iter, convert::TryInto};
   2
   3 use rustc::mir;
   4 use rustc::ty::layout::{Align, LayoutOf, Size};
   5 use rustc::hir::def_id::DefId;
   6 use rustc_apfloat::Float;
   7 use rustc::ty;
   8 use syntax::attr;
   9 use syntax::symbol::sym;
  10
  11 use crate::*;
  12
  13 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  14 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  15     /// Returns the minimum alignment for the target architecture for allocations of the given size.
  16     fn min_align(&self, size: u64, kind: MiriMemoryKind) -> Align {
  17         let this = self.eval_context_ref();
  18         // List taken from `libstd/sys_common/alloc.rs`.
  19         let min_align = match this.tcx.tcx.sess.target.target.arch.as_str() {
  20             "x86" | "arm" | "mips" | "powerpc" | "powerpc64" | "asmjs" | "wasm32" => 8,
  21             "x86_64" | "aarch64" | "mips64" | "s390x" | "sparc64" => 16,
  22             arch => bug!("Unsupported target architecture: {}", arch),
  23         };
  24         // Windows always aligns, even small allocations.
  25         // Source: <https://support.microsoft.com/en-us/help/286470/how-to-use-pageheap-exe-in-windows-xp-windows-2000-and-windows-server>
  26         // But jemalloc does not, so for the C heap we only align if the allocation is sufficiently big.
  27         if kind == MiriMemoryKind::WinHeap || size >= min_align {
  28             return Align::from_bytes(min_align).unwrap();
  29         }
  30         // We have `size < min_align`. Round `size` *down* to the next power of two and use that.
  31         fn prev_power_of_two(x: u64) -> u64 {
  32             let next_pow2 = x.next_power_of_two();
  33             if next_pow2 == x {
  34                 // x *is* a power of two, just use that.
  35                 x
  36             } else {
  37                 // x is between two powers, so next = 2*prev.
  38                 next_pow2 / 2
  39             }
  40         }
  41         Align::from_bytes(prev_power_of_two(size)).unwrap()
  42     }
  43
  44     fn malloc(&mut self, size: u64, zero_init: bool, kind: MiriMemoryKind) -> Scalar<Tag> {
  45         let this = self.eval_context_mut();
  46         if size == 0 {
  47             Scalar::from_int(0, this.pointer_size())
  48         } else {
  49             let align = this.min_align(size, kind);
  50             let ptr = this
  51                 .memory
  52                 .allocate(Size::from_bytes(size), align, kind.into());
  53             if zero_init {
  54                 // We just allocated this, the access is definitely in-bounds.
  55                 this.memory
  56                     .write_bytes(ptr.into(), iter::repeat(0u8).take(size as usize))
  57                     .unwrap();
  58             }
  59             Scalar::Ptr(ptr)
  60         }
  61     }
  62
  63     fn free(&mut self, ptr: Scalar<Tag>, kind: MiriMemoryKind) -> InterpResult<'tcx> {
  64         let this = self.eval_context_mut();
  65         if !this.is_null(ptr)? {
  66             let ptr = this.force_ptr(ptr)?;
  67             this.memory.deallocate(ptr, None, kind.into())?;
  68         }
  69         Ok(())
  70     }
  71
  72     fn realloc(
  73         &mut self,
  74         old_ptr: Scalar<Tag>,
  75         new_size: u64,
  76         kind: MiriMemoryKind,
  77     ) -> InterpResult<'tcx, Scalar<Tag>> {
  78         let this = self.eval_context_mut();
  79         let new_align = this.min_align(new_size, kind);
  80         if this.is_null(old_ptr)? {
  81             if new_size == 0 {
  82                 Ok(Scalar::from_int(0, this.pointer_size()))
  83             } else {
  84                 let new_ptr =
  85                     this.memory
  86                         .allocate(Size::from_bytes(new_size), new_align, kind.into());
  87                 Ok(Scalar::Ptr(new_ptr))
  88             }
  89         } else {
  90             let old_ptr = this.force_ptr(old_ptr)?;
  91             if new_size == 0 {
  92                 this.memory.deallocate(old_ptr, None, kind.into())?;
  93                 Ok(Scalar::from_int(0, this.pointer_size()))
  94             } else {
  95                 let new_ptr = this.memory.reallocate(
  96                     old_ptr,
  97                     None,
  98                     Size::from_bytes(new_size),
  99                     new_align,
 100                     kind.into(),
 101                 )?;
 102                 Ok(Scalar::Ptr(new_ptr))
 103             }
 104         }
 105     }
 106
 107     /// Emulates calling a foreign item, failing if the item is not supported.
 108     /// This function will handle `goto_block` if needed.
 109     /// Returns Ok(None) if the foreign item was completely handled
 110     /// by this function.
 111     /// Returns Ok(Some(body)) if processing the foreign item
 112     /// is delegated to another function.
 113     fn emulate_foreign_item(
 114         &mut self,
 115         def_id: DefId,
 116         args: &[OpTy<'tcx, Tag>],
 117         ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
 118         _unwind: Option<mir::BasicBlock>
 119     ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
 120         let this = self.eval_context_mut();
 121         let attrs = this.tcx.get_attrs(def_id);
 122         let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
 123             Some(name) => name.as_str(),
 124             None => this.tcx.item_name(def_id).as_str(),
 125         };
 126         // Strip linker suffixes (seen on 32-bit macOS).
 127         let link_name = link_name.trim_end_matches("$UNIX2003");
 128         let tcx = &{ this.tcx.tcx };
 129
 130         // First: functions that diverge.
 131         let (dest, ret) = match link_name {
 132             // Note that this matches calls to the *foreign* item `__rust_start_panic* -
 133             // that is, calls to `extern "Rust" { fn __rust_start_panic(...) }`.
 134             // We forward this to the underlying *implementation* in the panic runtime crate.
 135             // Normally, this will be either `libpanic_unwind` or `libpanic_abort`, but it could
 136             // also be a custom user-provided implementation via `#![feature(panic_runtime)]`
 137             "__rust_start_panic" => {
 138                 // FIXME we might want to cache this... but it's not really performance-critical.
 139                 let panic_runtime = tcx.crates().iter()
 140                     .find(|cnum| tcx.is_panic_runtime(**cnum))
 141                     .expect("No panic runtime found!");
 142                 let panic_runtime = tcx.crate_name(*panic_runtime);
 143                 let start_panic_instance = this.resolve_path(&[&*panic_runtime.as_str(), "__rust_start_panic"])?;
 144                 return Ok(Some(this.load_mir(start_panic_instance.def, None)?));
 145             }
 146             // Similarly, we forward calls to the `panic_impl` foreign item to its implementation.
 147             // The implementation is provided by the function with the `#[panic_handler]` attribute.
 148             "panic_impl" => {
 149                 let panic_impl_id = this.tcx.lang_items().panic_impl().unwrap();
 150                 let panic_impl_instance = ty::Instance::mono(*this.tcx, panic_impl_id);
 151                 return Ok(Some(this.load_mir(panic_impl_instance.def, None)?));
 152             }
 153
 154             "exit" | "ExitProcess" => {
 155                 // it's really u32 for ExitProcess, but we have to put it into the `Exit` variant anyway
 156                 let code = this.read_scalar(args[0])?.to_i32()?;
 157                 let ti = Box::new(TerminationInfo::Exit(code.into()));
 158                 return Err(InterpError::MachineStop(ti).into());
 159             }
 160             _ => {
 161                 if let Some(p) = ret {
 162                     p
 163                 } else {
 164                     throw_unsup_format!("can't call (diverging) foreign function: {}", link_name);
 165                 }
 166             }
 167         };
 168
 169         // Next: functions that return.
 170         match link_name {
 171             "malloc" => {
 172                 let size = this.read_scalar(args[0])?.to_machine_usize(this)?;
 173                 let res = this.malloc(size, /*zero_init:*/ false, MiriMemoryKind::C);
 174                 this.write_scalar(res, dest)?;
 175             }
 176             "calloc" => {
 177                 let items = this.read_scalar(args[0])?.to_machine_usize(this)?;
 178                 let len = this.read_scalar(args[1])?.to_machine_usize(this)?;
 179                 let size = items
 180                     .checked_mul(len)
 181                     .ok_or_else(|| err_panic!(Overflow(mir::BinOp::Mul)))?;
 182                 let res = this.malloc(size, /*zero_init:*/ true, MiriMemoryKind::C);
 183                 this.write_scalar(res, dest)?;
 184             }
 185             "posix_memalign" => {
 186                 let ret = this.deref_operand(args[0])?;
 187                 let align = this.read_scalar(args[1])?.to_machine_usize(this)?;
 188                 let size = this.read_scalar(args[2])?.to_machine_usize(this)?;
 189                 // Align must be power of 2, and also at least ptr-sized (POSIX rules).
 190                 if !align.is_power_of_two() {
 191                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 192                 }
 193                 if align < this.pointer_size().bytes() {
 194                     throw_ub_format!(
 195                         "posix_memalign: alignment must be at least the size of a pointer, but is {}",
 196                         align,
 197                     );
 198                 }
 199
 200                 if size == 0 {
 201                     this.write_null(ret.into())?;
 202                 } else {
 203                     let ptr = this.memory.allocate(
 204                         Size::from_bytes(size),
 205                         Align::from_bytes(align).unwrap(),
 206                         MiriMemoryKind::C.into(),
 207                     );
 208                     this.write_scalar(ptr, ret.into())?;
 209                 }
 210                 this.write_null(dest)?;
 211             }
 212             "free" => {
 213                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 214                 this.free(ptr, MiriMemoryKind::C)?;
 215             }
 216             "realloc" => {
 217                 let old_ptr = this.read_scalar(args[0])?.not_undef()?;
 218                 let new_size = this.read_scalar(args[1])?.to_machine_usize(this)?;
 219                 let res = this.realloc(old_ptr, new_size, MiriMemoryKind::C)?;
 220                 this.write_scalar(res, dest)?;
 221             }
 222
 223             "__rust_alloc" => {
 224                 let size = this.read_scalar(args[0])?.to_machine_usize(this)?;
 225                 let align = this.read_scalar(args[1])?.to_machine_usize(this)?;
 226                 if size == 0 {
 227                     throw_unsup!(HeapAllocZeroBytes);
 228                 }
 229                 if !align.is_power_of_two() {
 230                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 231                 }
 232                 let ptr = this.memory.allocate(
 233                     Size::from_bytes(size),
 234                     Align::from_bytes(align).unwrap(),
 235                     MiriMemoryKind::Rust.into(),
 236                 );
 237                 this.write_scalar(ptr, dest)?;
 238             }
 239             "__rust_alloc_zeroed" => {
 240                 let size = this.read_scalar(args[0])?.to_machine_usize(this)?;
 241                 let align = this.read_scalar(args[1])?.to_machine_usize(this)?;
 242                 if size == 0 {
 243                     throw_unsup!(HeapAllocZeroBytes);
 244                 }
 245                 if !align.is_power_of_two() {
 246                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 247                 }
 248                 let ptr = this.memory.allocate(
 249                     Size::from_bytes(size),
 250                     Align::from_bytes(align).unwrap(),
 251                     MiriMemoryKind::Rust.into(),
 252                 );
 253                 // We just allocated this, the access is definitely in-bounds.
 254                 this.memory
 255                     .write_bytes(ptr.into(), iter::repeat(0u8).take(size as usize))
 256                     .unwrap();
 257                 this.write_scalar(ptr, dest)?;
 258             }
 259             "__rust_dealloc" => {
 260                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 261                 let old_size = this.read_scalar(args[1])?.to_machine_usize(this)?;
 262                 let align = this.read_scalar(args[2])?.to_machine_usize(this)?;
 263                 if old_size == 0 {
 264                     throw_unsup!(HeapAllocZeroBytes);
 265                 }
 266                 if !align.is_power_of_two() {
 267                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 268                 }
 269                 let ptr = this.force_ptr(ptr)?;
 270                 this.memory.deallocate(
 271                     ptr,
 272                     Some((
 273                         Size::from_bytes(old_size),
 274                         Align::from_bytes(align).unwrap(),
 275                     )),
 276                     MiriMemoryKind::Rust.into(),
 277                 )?;
 278             }
 279             "__rust_realloc" => {
 280                 let ptr = this.read_scalar(args[0])?.to_ptr()?;
 281                 let old_size = this.read_scalar(args[1])?.to_machine_usize(this)?;
 282                 let align = this.read_scalar(args[2])?.to_machine_usize(this)?;
 283                 let new_size = this.read_scalar(args[3])?.to_machine_usize(this)?;
 284                 if old_size == 0 || new_size == 0 {
 285                     throw_unsup!(HeapAllocZeroBytes);
 286                 }
 287                 if !align.is_power_of_two() {
 288                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 289                 }
 290                 let align = Align::from_bytes(align).unwrap();
 291                 let new_ptr = this.memory.reallocate(
 292                     ptr,
 293                     Some((Size::from_bytes(old_size), align)),
 294                     Size::from_bytes(new_size),
 295                     align,
 296                     MiriMemoryKind::Rust.into(),
 297                 )?;
 298                 this.write_scalar(new_ptr, dest)?;
 299             }
 300
 301             "syscall" => {
 302                 let sys_getrandom = this
 303                     .eval_path_scalar(&["libc", "SYS_getrandom"])?
 304                     .expect("Failed to get libc::SYS_getrandom")
 305                     .to_machine_usize(this)?;
 306
 307                 // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
 308                 // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
 309                 match this.read_scalar(args[0])?.to_machine_usize(this)? {
 310                     id if id == sys_getrandom => {
 311                         // The first argument is the syscall id,
 312                         // so skip over it.
 313                         linux_getrandom(this, &args[1..], dest)?;
 314                     }
 315                     id => throw_unsup_format!("miri does not support syscall ID {}", id),
 316                 }
 317             }
 318
 319             "getrandom" => {
 320                 linux_getrandom(this, args, dest)?;
 321             }
 322
 323             "dlsym" => {
 324                 let _handle = this.read_scalar(args[0])?;
 325                 let symbol = this.read_scalar(args[1])?.not_undef()?;
 326                 let symbol_name = this.memory.read_c_str(symbol)?;
 327                 let err = format!("bad c unicode symbol: {:?}", symbol_name);
 328                 let symbol_name = ::std::str::from_utf8(symbol_name).unwrap_or(&err);
 329                 if let Some(dlsym) = Dlsym::from_str(symbol_name)? {
 330                     let ptr = this.memory.create_fn_alloc(FnVal::Other(dlsym));
 331                     this.write_scalar(Scalar::from(ptr), dest)?;
 332                 } else {
 333                     this.write_null(dest)?;
 334                 }
 335             }
 336
 337             "__rust_maybe_catch_panic" => {
 338                 this.handle_catch_panic(args, dest, ret)?;
 339                 return Ok(None)
 340             }
 341
 342             "memcmp" => {
 343                 let left = this.read_scalar(args[0])?.not_undef()?;
 344                 let right = this.read_scalar(args[1])?.not_undef()?;
 345                 let n = Size::from_bytes(this.read_scalar(args[2])?.to_machine_usize(this)?);
 346
 347                 let result = {
 348                     let left_bytes = this.memory.read_bytes(left, n)?;
 349                     let right_bytes = this.memory.read_bytes(right, n)?;
 350
 351                     use std::cmp::Ordering::*;
 352                     match left_bytes.cmp(right_bytes) {
 353                         Less => -1i32,
 354                         Equal => 0,
 355                         Greater => 1,
 356                     }
 357                 };
 358
 359                 this.write_scalar(Scalar::from_int(result, Size::from_bits(32)), dest)?;
 360             }
 361
 362             "memrchr" => {
 363                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 364                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 365                 let num = this.read_scalar(args[2])?.to_machine_usize(this)?;
 366                 if let Some(idx) = this
 367                     .memory
 368                     .read_bytes(ptr, Size::from_bytes(num))?
 369                     .iter()
 370                     .rev()
 371                     .position(|&c| c == val)
 372                 {
 373                     let new_ptr = ptr.ptr_offset(Size::from_bytes(num - idx as u64 - 1), this)?;
 374                     this.write_scalar(new_ptr, dest)?;
 375                 } else {
 376                     this.write_null(dest)?;
 377                 }
 378             }
 379
 380             "memchr" => {
 381                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 382                 let val = this.read_scalar(args[1])?.to_i32()? as u8;
 383                 let num = this.read_scalar(args[2])?.to_machine_usize(this)?;
 384                 let idx = this
 385                     .memory
 386                     .read_bytes(ptr, Size::from_bytes(num))?
 387                     .iter()
 388                     .position(|&c| c == val);
 389                 if let Some(idx) = idx {
 390                     let new_ptr = ptr.ptr_offset(Size::from_bytes(idx as u64), this)?;
 391                     this.write_scalar(new_ptr, dest)?;
 392                 } else {
 393                     this.write_null(dest)?;
 394                 }
 395             }
 396
 397             "__errno_location" | "__error" => {
 398                 let errno_place = this.machine.last_error.unwrap();
 399                 this.write_scalar(errno_place.to_ref().to_scalar()?, dest)?;
 400             }
 401
 402             "getenv" => {
 403                 let result = this.getenv(args[0])?;
 404                 this.write_scalar(result, dest)?;
 405             }
 406
 407             "unsetenv" => {
 408                 let result = this.unsetenv(args[0])?;
 409                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 410             }
 411
 412             "setenv" => {
 413                 let result = this.setenv(args[0], args[1])?;
 414                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 415             }
 416
 417             "getcwd" => {
 418                 let result = this.getcwd(args[0], args[1])?;
 419                 this.write_scalar(result, dest)?;
 420             }
 421
 422             "chdir" => {
 423                 let result = this.chdir(args[0])?;
 424                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 425             }
 426
 427             "open" | "open64" => {
 428                 let result = this.open(args[0], args[1])?;
 429                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 430             }
 431
 432             "fcntl" => {
 433                 let result = this.fcntl(args[0], args[1], args.get(2).cloned())?;
 434                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 435             }
 436
 437             "close" | "close$NOCANCEL" => {
 438                 let result = this.close(args[0])?;
 439                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 440             }
 441
 442             "read" => {
 443                 let result = this.read(args[0], args[1], args[2])?;
 444                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 445             }
 446
 447             "write" => {
 448                 let fd = this.read_scalar(args[0])?.to_i32()?;
 449                 let buf = this.read_scalar(args[1])?.not_undef()?;
 450                 let n = this.read_scalar(args[2])?.to_machine_usize(tcx)?;
 451                 trace!("Called write({:?}, {:?}, {:?})", fd, buf, n);
 452                 let result = if fd == 1 || fd == 2 {
 453                     // stdout/stderr
 454                     use std::io::{self, Write};
 455
 456                     let buf_cont = this.memory.read_bytes(buf, Size::from_bytes(n))?;
 457                     // We need to flush to make sure this actually appears on the screen
 458                     let res = if fd == 1 {
 459                         // Stdout is buffered, flush to make sure it appears on the screen.
 460                         // This is the write() syscall of the interpreted program, we want it
 461                         // to correspond to a write() syscall on the host -- there is no good
 462                         // in adding extra buffering here.
 463                         let res = io::stdout().write(buf_cont);
 464                         io::stdout().flush().unwrap();
 465                         res
 466                     } else {
 467                         // No need to flush, stderr is not buffered.
 468                         io::stderr().write(buf_cont)
 469                     };
 470                     match res {
 471                         Ok(n) => n as i64,
 472                         Err(_) => -1,
 473                     }
 474                 } else {
 475                     this.write(args[0], args[1], args[2])?
 476                 };
 477                 // Now, `result` is the value we return back to the program.
 478                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 479             }
 480
 481             "unlink" => {
 482                 let result = this.unlink(args[0])?;
 483                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 484             }
 485
 486             "clock_gettime" => {
 487                 let result = this.clock_gettime(args[0], args[1])?;
 488                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 489             }
 490
 491             "gettimeofday" => {
 492                 let result = this.gettimeofday(args[0], args[1])?;
 493                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 494             }
 495
 496             "strlen" => {
 497                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 498                 let n = this.memory.read_c_str(ptr)?.len();
 499                 this.write_scalar(Scalar::from_uint(n as u64, dest.layout.size), dest)?;
 500             }
 501
 502             // math functions
 503             "cbrtf" | "coshf" | "sinhf" | "tanf" | "acosf" | "asinf" | "atanf" => {
 504                 // FIXME: Using host floats.
 505                 let f = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 506                 let f = match link_name {
 507                     "cbrtf" => f.cbrt(),
 508                     "coshf" => f.cosh(),
 509                     "sinhf" => f.sinh(),
 510                     "tanf" => f.tan(),
 511                     "acosf" => f.acos(),
 512                     "asinf" => f.asin(),
 513                     "atanf" => f.atan(),
 514                     _ => bug!(),
 515                 };
 516                 this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
 517             }
 518             // underscore case for windows
 519             "_hypotf" | "hypotf" | "atan2f" => {
 520                 // FIXME: Using host floats.
 521                 let f1 = f32::from_bits(this.read_scalar(args[0])?.to_u32()?);
 522                 let f2 = f32::from_bits(this.read_scalar(args[1])?.to_u32()?);
 523                 let n = match link_name {
 524                     "_hypotf" | "hypotf" => f1.hypot(f2),
 525                     "atan2f" => f1.atan2(f2),
 526                     _ => bug!(),
 527                 };
 528                 this.write_scalar(Scalar::from_u32(n.to_bits()), dest)?;
 529             }
 530
 531             "cbrt" | "cosh" | "sinh" | "tan" | "acos" | "asin" | "atan" => {
 532                 // FIXME: Using host floats.
 533                 let f = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 534                 let f = match link_name {
 535                     "cbrt" => f.cbrt(),
 536                     "cosh" => f.cosh(),
 537                     "sinh" => f.sinh(),
 538                     "tan" => f.tan(),
 539                     "acos" => f.acos(),
 540                     "asin" => f.asin(),
 541                     "atan" => f.atan(),
 542                     _ => bug!(),
 543                 };
 544                 this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
 545             }
 546             // underscore case for windows, here and below
 547             // (see https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/floating-point-primitives?view=vs-2019)
 548             "_hypot" | "hypot" | "atan2" => {
 549                 // FIXME: Using host floats.
 550                 let f1 = f64::from_bits(this.read_scalar(args[0])?.to_u64()?);
 551                 let f2 = f64::from_bits(this.read_scalar(args[1])?.to_u64()?);
 552                 let n = match link_name {
 553                     "_hypot" | "hypot" => f1.hypot(f2),
 554                     "atan2" => f1.atan2(f2),
 555                     _ => bug!(),
 556                 };
 557                 this.write_scalar(Scalar::from_u64(n.to_bits()), dest)?;
 558             }
 559             // For radix-2 (binary) systems, `ldexp` and `scalbn` are the same.
 560             "_ldexp" | "ldexp" | "scalbn" => {
 561                 let x = this.read_scalar(args[0])?.to_f64()?;
 562                 let exp = this.read_scalar(args[1])?.to_i32()?;
 563
 564                 // Saturating cast to i16. Even those are outside the valid exponent range to
 565                 // `scalbn` below will do its over/underflow handling.
 566                 let exp = if exp > i16::max_value() as i32 {
 567                     i16::max_value()
 568                 } else if exp < i16::min_value() as i32 {
 569                     i16::min_value()
 570                 } else {
 571                     exp.try_into().unwrap()
 572                 };
 573
 574                 let res = x.scalbn(exp);
 575                 this.write_scalar(Scalar::from_f64(res), dest)?;
 576             }
 577
 578             // Some things needed for `sys::thread` initialization to go through.
 579             "signal" | "sigaction" | "sigaltstack" => {
 580                 this.write_scalar(Scalar::from_int(0, dest.layout.size), dest)?;
 581             }
 582
 583             "sysconf" => {
 584                 let name = this.read_scalar(args[0])?.to_i32()?;
 585
 586                 trace!("sysconf() called with name {}", name);
 587                 // TODO: Cache the sysconf integers via Miri's global cache.
 588                 let paths = &[
 589                     (
 590                         &["libc", "_SC_PAGESIZE"],
 591                         Scalar::from_int(PAGE_SIZE, dest.layout.size),
 592                     ),
 593                     (
 594                         &["libc", "_SC_GETPW_R_SIZE_MAX"],
 595                         Scalar::from_int(-1, dest.layout.size),
 596                     ),
 597                     (
 598                         &["libc", "_SC_NPROCESSORS_ONLN"],
 599                         Scalar::from_int(NUM_CPUS, dest.layout.size),
 600                     ),
 601                 ];
 602                 let mut result = None;
 603                 for &(path, path_value) in paths {
 604                     if let Some(val) = this.eval_path_scalar(path)? {
 605                         let val = val.to_i32()?;
 606                         if val == name {
 607                             result = Some(path_value);
 608                             break;
 609                         }
 610                     }
 611                 }
 612                 if let Some(result) = result {
 613                     this.write_scalar(result, dest)?;
 614                 } else {
 615                     throw_unsup_format!("Unimplemented sysconf name: {}", name)
 616                 }
 617             }
 618
 619             "sched_getaffinity" => {
 620                 // Return an error; `num_cpus` then falls back to `sysconf`.
 621                 this.write_scalar(Scalar::from_int(-1, dest.layout.size), dest)?;
 622             }
 623
 624             "isatty" => {
 625                 this.write_null(dest)?;
 626             }
 627
 628             // Hook pthread calls that go to the thread-local storage memory subsystem.
 629             "pthread_key_create" => {
 630                 let key_place = this.deref_operand(args[0])?;
 631
 632                 // Extract the function type out of the signature (that seems easier than constructing it ourselves).
 633                 let dtor = match this.test_null(this.read_scalar(args[1])?.not_undef()?)? {
 634                     Some(dtor_ptr) => Some(this.memory.get_fn(dtor_ptr)?.as_instance()?),
 635                     None => None,
 636                 };
 637
 638                 // Figure out how large a pthread TLS key actually is.
 639                 // This is `libc::pthread_key_t`.
 640                 let key_type = args[0].layout.ty
 641                     .builtin_deref(true)
 642                     .ok_or_else(|| err_ub_format!(
 643                         "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
 644                     ))?
 645                     .ty;
 646                 let key_layout = this.layout_of(key_type)?;
 647
 648                 // Create key and write it into the memory where `key_ptr` wants it.
 649                 let key = this.machine.tls.create_tls_key(dtor) as u128;
 650                 if key_layout.size.bits() < 128 && key >= (1u128 << key_layout.size.bits() as u128)
 651                 {
 652                     throw_unsup!(OutOfTls);
 653                 }
 654
 655                 this.write_scalar(Scalar::from_uint(key, key_layout.size), key_place.into())?;
 656
 657                 // Return success (`0`).
 658                 this.write_null(dest)?;
 659             }
 660             "pthread_key_delete" => {
 661                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 662                 this.machine.tls.delete_tls_key(key)?;
 663                 // Return success (0)
 664                 this.write_null(dest)?;
 665             }
 666             "pthread_getspecific" => {
 667                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 668                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 669                 this.write_scalar(ptr, dest)?;
 670             }
 671             "pthread_setspecific" => {
 672                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 673                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 674                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 675
 676                 // Return success (`0`).
 677                 this.write_null(dest)?;
 678             }
 679
 680             // Stack size/address stuff.
 681             "pthread_attr_init"
 682             | "pthread_attr_destroy"
 683             | "pthread_self"
 684             | "pthread_attr_setstacksize" => {
 685                 this.write_null(dest)?;
 686             }
 687             "pthread_attr_getstack" => {
 688                 let addr_place = this.deref_operand(args[1])?;
 689                 let size_place = this.deref_operand(args[2])?;
 690
 691                 this.write_scalar(
 692                     Scalar::from_uint(STACK_ADDR, addr_place.layout.size),
 693                     addr_place.into(),
 694                 )?;
 695                 this.write_scalar(
 696                     Scalar::from_uint(STACK_SIZE, size_place.layout.size),
 697                     size_place.into(),
 698                 )?;
 699
 700                 // Return success (`0`).
 701                 this.write_null(dest)?;
 702             }
 703
 704             // We don't support threading. (Also for Windows.)
 705             "pthread_create" | "CreateThread" => {
 706                 throw_unsup_format!("Miri does not support threading");
 707             }
 708
 709             // Stub out calls for condvar, mutex and rwlock, to just return `0`.
 710             "pthread_mutexattr_init"
 711             | "pthread_mutexattr_settype"
 712             | "pthread_mutex_init"
 713             | "pthread_mutexattr_destroy"
 714             | "pthread_mutex_lock"
 715             | "pthread_mutex_unlock"
 716             | "pthread_mutex_destroy"
 717             | "pthread_rwlock_rdlock"
 718             | "pthread_rwlock_unlock"
 719             | "pthread_rwlock_wrlock"
 720             | "pthread_rwlock_destroy"
 721             | "pthread_condattr_init"
 722             | "pthread_condattr_setclock"
 723             | "pthread_cond_init"
 724             | "pthread_condattr_destroy"
 725             | "pthread_cond_destroy" => {
 726                 this.write_null(dest)?;
 727             }
 728
 729             // We don't support fork so we don't have to do anything for atfork.
 730             "pthread_atfork" => {
 731                 this.write_null(dest)?;
 732             }
 733
 734             "mmap" => {
 735                 // 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.
 736                 let addr = this.read_scalar(args[0])?.not_undef()?;
 737                 this.write_scalar(addr, dest)?;
 738             }
 739             "mprotect" => {
 740                 this.write_null(dest)?;
 741             }
 742
 743             // macOS API stubs.
 744             "pthread_attr_get_np" | "pthread_getattr_np" => {
 745                 this.write_null(dest)?;
 746             }
 747             "pthread_get_stackaddr_np" => {
 748                 let stack_addr = Scalar::from_uint(STACK_ADDR, dest.layout.size);
 749                 this.write_scalar(stack_addr, dest)?;
 750             }
 751             "pthread_get_stacksize_np" => {
 752                 let stack_size = Scalar::from_uint(STACK_SIZE, dest.layout.size);
 753                 this.write_scalar(stack_size, dest)?;
 754             }
 755             "_tlv_atexit" => {
 756                 // FIXME: register the destructor.
 757             }
 758             "_NSGetArgc" => {
 759                 this.write_scalar(this.machine.argc.expect("machine must be initialized"), dest)?;
 760             }
 761             "_NSGetArgv" => {
 762                 this.write_scalar(this.machine.argv.expect("machine must be initialized"), dest)?;
 763             }
 764             "SecRandomCopyBytes" => {
 765                 let len = this.read_scalar(args[1])?.to_machine_usize(this)?;
 766                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 767                 this.gen_random(ptr, len as usize)?;
 768                 this.write_null(dest)?;
 769             }
 770
 771             // Windows API stubs.
 772             // HANDLE = isize
 773             // DWORD = ULONG = u32
 774             // BOOL = i32
 775             "GetProcessHeap" => {
 776                 // Just fake a HANDLE
 777                 this.write_scalar(Scalar::from_int(1, this.pointer_size()), dest)?;
 778             }
 779             "HeapAlloc" => {
 780                 let _handle = this.read_scalar(args[0])?.to_machine_isize(this)?;
 781                 let flags = this.read_scalar(args[1])?.to_u32()?;
 782                 let size = this.read_scalar(args[2])?.to_machine_usize(this)?;
 783                 let zero_init = (flags & 0x00000008) != 0; // HEAP_ZERO_MEMORY
 784                 let res = this.malloc(size, zero_init, MiriMemoryKind::WinHeap);
 785                 this.write_scalar(res, dest)?;
 786             }
 787             "HeapFree" => {
 788                 let _handle = this.read_scalar(args[0])?.to_machine_isize(this)?;
 789                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 790                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 791                 this.free(ptr, MiriMemoryKind::WinHeap)?;
 792                 this.write_scalar(Scalar::from_int(1, Size::from_bytes(4)), dest)?;
 793             }
 794             "HeapReAlloc" => {
 795                 let _handle = this.read_scalar(args[0])?.to_machine_isize(this)?;
 796                 let _flags = this.read_scalar(args[1])?.to_u32()?;
 797                 let ptr = this.read_scalar(args[2])?.not_undef()?;
 798                 let size = this.read_scalar(args[3])?.to_machine_usize(this)?;
 799                 let res = this.realloc(ptr, size, MiriMemoryKind::WinHeap)?;
 800                 this.write_scalar(res, dest)?;
 801             }
 802
 803             "SetLastError" => {
 804                 this.set_last_error(this.read_scalar(args[0])?.not_undef()?)?;
 805             }
 806             "GetLastError" => {
 807                 let last_error = this.get_last_error()?;
 808                 this.write_scalar(last_error, dest)?;
 809             }
 810
 811             "AddVectoredExceptionHandler" => {
 812                 // Any non zero value works for the stdlib. This is just used for stack overflows anyway.
 813                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 814             }
 815             "InitializeCriticalSection"
 816             | "EnterCriticalSection"
 817             | "LeaveCriticalSection"
 818             | "DeleteCriticalSection" => {
 819                 // Nothing to do, not even a return value.
 820             }
 821             "GetModuleHandleW"
 822             | "GetProcAddress"
 823             | "TryEnterCriticalSection"
 824             | "GetConsoleScreenBufferInfo"
 825             | "SetConsoleTextAttribute" => {
 826                 // Pretend these do not exist / nothing happened, by returning zero.
 827                 this.write_null(dest)?;
 828             }
 829             "GetSystemInfo" => {
 830                 let system_info = this.deref_operand(args[0])?;
 831                 // Initialize with `0`.
 832                 this.memory
 833                     .write_bytes(system_info.ptr, iter::repeat(0u8).take(system_info.layout.size.bytes() as usize))?;
 834                 // Set number of processors.
 835                 let dword_size = Size::from_bytes(4);
 836                 let num_cpus = this.mplace_field(system_info, 6)?;
 837                 this.write_scalar(
 838                     Scalar::from_int(NUM_CPUS, dword_size),
 839                     num_cpus.into(),
 840                 )?;
 841             }
 842
 843             "TlsAlloc" => {
 844                 // This just creates a key; Windows does not natively support TLS destructors.
 845
 846                 // Create key and return it.
 847                 let key = this.machine.tls.create_tls_key(None) as u128;
 848
 849                 // Figure out how large a TLS key actually is. This is `c::DWORD`.
 850                 if dest.layout.size.bits() < 128
 851                     && key >= (1u128 << dest.layout.size.bits() as u128)
 852                 {
 853                     throw_unsup!(OutOfTls);
 854                 }
 855                 this.write_scalar(Scalar::from_uint(key, dest.layout.size), dest)?;
 856             }
 857             "TlsGetValue" => {
 858                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 859                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 860                 this.write_scalar(ptr, dest)?;
 861             }
 862             "TlsSetValue" => {
 863                 let key = this.read_scalar(args[0])?.to_u32()? as u128;
 864                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 865                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 866
 867                 // Return success (`1`).
 868                 this.write_scalar(Scalar::from_int(1, dest.layout.size), dest)?;
 869             }
 870             "GetStdHandle" => {
 871                 let which = this.read_scalar(args[0])?.to_i32()?;
 872                 // We just make this the identity function, so we know later in `WriteFile`
 873                 // which one it is.
 874                 this.write_scalar(Scalar::from_int(which, this.pointer_size()), dest)?;
 875             }
 876             "WriteFile" => {
 877                 let handle = this.read_scalar(args[0])?.to_machine_isize(this)?;
 878                 let buf = this.read_scalar(args[1])?.not_undef()?;
 879                 let n = this.read_scalar(args[2])?.to_u32()?;
 880                 let written_place = this.deref_operand(args[3])?;
 881                 // Spec says to always write `0` first.
 882                 this.write_null(written_place.into())?;
 883                 let written = if handle == -11 || handle == -12 {
 884                     // stdout/stderr
 885                     use std::io::{self, Write};
 886
 887                     let buf_cont = this
 888                         .memory
 889                         .read_bytes(buf, Size::from_bytes(u64::from(n)))?;
 890                     let res = if handle == -11 {
 891                         io::stdout().write(buf_cont)
 892                     } else {
 893                         io::stderr().write(buf_cont)
 894                     };
 895                     res.ok().map(|n| n as u32)
 896                 } else {
 897                     eprintln!("Miri: Ignored output to handle {}", handle);
 898                     // Pretend it all went well.
 899                     Some(n)
 900                 };
 901                 // If there was no error, write back how much was written.
 902                 if let Some(n) = written {
 903                     this.write_scalar(Scalar::from_u32(n), written_place.into())?;
 904                 }
 905                 // Return whether this was a success.
 906                 this.write_scalar(
 907                     Scalar::from_int(if written.is_some() { 1 } else { 0 }, dest.layout.size),
 908                     dest,
 909                 )?;
 910             }
 911             "GetConsoleMode" => {
 912                 // Everything is a pipe.
 913                 this.write_null(dest)?;
 914             }
 915             "GetEnvironmentVariableW" => {
 916                 // This is not the env var you are looking for.
 917                 this.set_last_error(Scalar::from_u32(203))?; // ERROR_ENVVAR_NOT_FOUND
 918                 this.write_null(dest)?;
 919             }
 920             "GetCommandLineW" => {
 921                 this.write_scalar(this.machine.cmd_line.expect("machine must be initialized"), dest)?;
 922             }
 923             // The actual name of 'RtlGenRandom'
 924             "SystemFunction036" => {
 925                 let ptr = this.read_scalar(args[0])?.not_undef()?;
 926                 let len = this.read_scalar(args[1])?.to_u32()?;
 927                 this.gen_random(ptr, len as usize)?;
 928                 this.write_scalar(Scalar::from_bool(true), dest)?;
 929             }
 930
 931             // We can't execute anything else.
 932             _ => throw_unsup_format!("can't call foreign function: {}", link_name),
 933         }
 934
 935         this.dump_place(*dest);
 936         this.go_to_block(ret);
 937         Ok(None)
 938     }
 939
 940     /// Evaluates the scalar at the specified path. Returns Some(val)
 941     /// if the path could be resolved, and None otherwise
 942     fn eval_path_scalar(
 943         &mut self,
 944         path: &[&str],
 945     ) -> InterpResult<'tcx, Option<ScalarMaybeUndef<Tag>>> {
 946         let this = self.eval_context_mut();
 947         if let Ok(instance) = this.resolve_path(path) {
 948             let cid = GlobalId {
 949                 instance,
 950                 promoted: None,
 951             };
 952             let const_val = this.const_eval_raw(cid)?;
 953             let const_val = this.read_scalar(const_val.into())?;
 954             return Ok(Some(const_val));
 955         }
 956         return Ok(None);
 957     }
 958 }
 959
 960 // Shims the linux 'getrandom()' syscall.
 961 fn linux_getrandom<'tcx>(
 962     this: &mut MiriEvalContext<'_, 'tcx>,
 963     args: &[OpTy<'tcx, Tag>],
 964     dest: PlaceTy<'tcx, Tag>,
 965 ) -> InterpResult<'tcx> {
 966     let ptr = this.read_scalar(args[0])?.not_undef()?;
 967     let len = this.read_scalar(args[1])?.to_machine_usize(this)?;
 968
 969     // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
 970     // neither of which have any effect on our current PRNG.
 971     let _flags = this.read_scalar(args[2])?.to_i32()?;
 972
 973     this.gen_random(ptr, len as usize)?;
 974     this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?;
 975     Ok(())
 976 }