src/shims/foreign_items/posix.rs

   1 mod linux;
   2 mod macos;
   3
   4 use crate::*;
   5 use rustc::mir;
   6 use rustc::ty::layout::{Align, LayoutOf, Size};
   7
   8 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
   9 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  10     fn emulate_foreign_item_by_name(
  11         &mut self,
  12         link_name: &str,
  13         args: &[OpTy<'tcx, Tag>],
  14         dest: PlaceTy<'tcx, Tag>,
  15         ret: mir::BasicBlock,
  16     ) -> InterpResult<'tcx, bool> {
  17         let this = self.eval_context_mut();
  18         let tcx = &{ this.tcx.tcx };
  19
  20         match link_name {
  21             // Environment related shims
  22             "getenv" => {
  23                 let result = this.getenv(args[0])?;
  24                 this.write_scalar(result, dest)?;
  25             }
  26
  27             "unsetenv" => {
  28                 let result = this.unsetenv(args[0])?;
  29                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  30             }
  31
  32             "setenv" => {
  33                 let result = this.setenv(args[0], args[1])?;
  34                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  35             }
  36
  37             "getcwd" => {
  38                 let result = this.getcwd(args[0], args[1])?;
  39                 this.write_scalar(result, dest)?;
  40             }
  41
  42             "chdir" => {
  43                 let result = this.chdir(args[0])?;
  44                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  45             }
  46
  47             // File related shims
  48             "open" | "open64" => {
  49                 let result = this.open(args[0], args[1])?;
  50                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  51             }
  52
  53             "fcntl" => {
  54                 let result = this.fcntl(args[0], args[1], args.get(2).cloned())?;
  55                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  56             }
  57
  58             "read" => {
  59                 let result = this.read(args[0], args[1], args[2])?;
  60                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  61             }
  62
  63             "write" => {
  64                 let fd = this.read_scalar(args[0])?.to_i32()?;
  65                 let buf = this.read_scalar(args[1])?.not_undef()?;
  66                 let n = this.read_scalar(args[2])?.to_machine_usize(tcx)?;
  67                 trace!("Called write({:?}, {:?}, {:?})", fd, buf, n);
  68                 let result = if fd == 1 || fd == 2 {
  69                     // stdout/stderr
  70                     use std::io::{self, Write};
  71
  72                     let buf_cont = this.memory.read_bytes(buf, Size::from_bytes(n))?;
  73                     // We need to flush to make sure this actually appears on the screen
  74                     let res = if fd == 1 {
  75                         // Stdout is buffered, flush to make sure it appears on the screen.
  76                         // This is the write() syscall of the interpreted program, we want it
  77                         // to correspond to a write() syscall on the host -- there is no good
  78                         // in adding extra buffering here.
  79                         let res = io::stdout().write(buf_cont);
  80                         io::stdout().flush().unwrap();
  81                         res
  82                     } else {
  83                         // No need to flush, stderr is not buffered.
  84                         io::stderr().write(buf_cont)
  85                     };
  86                     match res {
  87                         Ok(n) => n as i64,
  88                         Err(_) => -1,
  89                     }
  90                 } else {
  91                     this.write(args[0], args[1], args[2])?
  92                 };
  93                 // Now, `result` is the value we return back to the program.
  94                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
  95             }
  96
  97             "unlink" => {
  98                 let result = this.unlink(args[0])?;
  99                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 100             }
 101
 102             "symlink" => {
 103                 let result = this.symlink(args[0], args[1])?;
 104                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 105             }
 106
 107             "rename" => {
 108                 let result = this.rename(args[0], args[1])?;
 109                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 110             }
 111
 112             "lseek" | "lseek64" => {
 113                 let result = this.lseek64(args[0], args[1], args[2])?;
 114                 this.write_scalar(Scalar::from_int(result, dest.layout.size), dest)?;
 115             }
 116
 117             // Other shims
 118             "posix_memalign" => {
 119                 let ret = this.deref_operand(args[0])?;
 120                 let align = this.read_scalar(args[1])?.to_machine_usize(this)?;
 121                 let size = this.read_scalar(args[2])?.to_machine_usize(this)?;
 122                 // Align must be power of 2, and also at least ptr-sized (POSIX rules).
 123                 if !align.is_power_of_two() {
 124                     throw_unsup!(HeapAllocNonPowerOfTwoAlignment(align));
 125                 }
 126                 if align < this.pointer_size().bytes() {
 127                     throw_ub_format!(
 128                         "posix_memalign: alignment must be at least the size of a pointer, but is {}",
 129                         align,
 130                     );
 131                 }
 132
 133                 if size == 0 {
 134                     this.write_null(ret.into())?;
 135                 } else {
 136                     let ptr = this.memory.allocate(
 137                         Size::from_bytes(size),
 138                         Align::from_bytes(align).unwrap(),
 139                         MiriMemoryKind::C.into(),
 140                     );
 141                     this.write_scalar(ptr, ret.into())?;
 142                 }
 143                 this.write_null(dest)?;
 144             }
 145
 146             "dlsym" => {
 147                 let _handle = this.read_scalar(args[0])?;
 148                 let symbol = this.read_scalar(args[1])?.not_undef()?;
 149                 let symbol_name = this.memory.read_c_str(symbol)?;
 150                 let err = format!("bad c unicode symbol: {:?}", symbol_name);
 151                 let symbol_name = ::std::str::from_utf8(symbol_name).unwrap_or(&err);
 152                 if let Some(dlsym) = Dlsym::from_str(symbol_name)? {
 153                     let ptr = this.memory.create_fn_alloc(FnVal::Other(dlsym));
 154                     this.write_scalar(Scalar::from(ptr), dest)?;
 155                 } else {
 156                     this.write_null(dest)?;
 157                 }
 158             }
 159
 160             // Hook pthread calls that go to the thread-local storage memory subsystem.
 161             "pthread_key_create" => {
 162                 let key_place = this.deref_operand(args[0])?;
 163
 164                 // Extract the function type out of the signature (that seems easier than constructing it ourselves).
 165                 let dtor = match this.test_null(this.read_scalar(args[1])?.not_undef()?)? {
 166                     Some(dtor_ptr) => Some(this.memory.get_fn(dtor_ptr)?.as_instance()?),
 167                     None => None,
 168                 };
 169
 170                 // Figure out how large a pthread TLS key actually is.
 171                 // This is `libc::pthread_key_t`.
 172                 let key_type = args[0].layout.ty
 173                     .builtin_deref(true)
 174                     .ok_or_else(|| err_ub_format!(
 175                         "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
 176                     ))?
 177                     .ty;
 178                 let key_layout = this.layout_of(key_type)?;
 179
 180                 // Create key and write it into the memory where `key_ptr` wants it.
 181                 let key = this.machine.tls.create_tls_key(dtor) as u128;
 182                 if key_layout.size.bits() < 128 && key >= (1u128 << key_layout.size.bits() as u128)
 183                 {
 184                     throw_unsup!(OutOfTls);
 185                 }
 186
 187                 this.write_scalar(Scalar::from_uint(key, key_layout.size), key_place.into())?;
 188
 189                 // Return success (`0`).
 190                 this.write_null(dest)?;
 191             }
 192             "pthread_key_delete" => {
 193                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 194                 this.machine.tls.delete_tls_key(key)?;
 195                 // Return success (0)
 196                 this.write_null(dest)?;
 197             }
 198             "pthread_getspecific" => {
 199                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 200                 let ptr = this.machine.tls.load_tls(key, tcx)?;
 201                 this.write_scalar(ptr, dest)?;
 202             }
 203             "pthread_setspecific" => {
 204                 let key = this.read_scalar(args[0])?.to_bits(args[0].layout.size)?;
 205                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 206                 this.machine.tls.store_tls(key, this.test_null(new_ptr)?)?;
 207
 208                 // Return success (`0`).
 209                 this.write_null(dest)?;
 210             }
 211
 212             // Stack size/address stuff.
 213             | "pthread_attr_init"
 214             | "pthread_attr_destroy"
 215             | "pthread_self"
 216             | "pthread_attr_setstacksize" => {
 217                 this.write_null(dest)?;
 218             }
 219             "pthread_attr_getstack" => {
 220                 let addr_place = this.deref_operand(args[1])?;
 221                 let size_place = this.deref_operand(args[2])?;
 222
 223                 this.write_scalar(
 224                     Scalar::from_uint(STACK_ADDR, addr_place.layout.size),
 225                     addr_place.into(),
 226                 )?;
 227                 this.write_scalar(
 228                     Scalar::from_uint(STACK_SIZE, size_place.layout.size),
 229                     size_place.into(),
 230                 )?;
 231
 232                 // Return success (`0`).
 233                 this.write_null(dest)?;
 234             }
 235
 236             // We don't support threading.
 237             "pthread_create" => {
 238                 throw_unsup_format!("Miri does not support threading");
 239             }
 240
 241             // Stub out calls for condvar, mutex and rwlock, to just return `0`.
 242             | "pthread_mutexattr_init"
 243             | "pthread_mutexattr_settype"
 244             | "pthread_mutex_init"
 245             | "pthread_mutexattr_destroy"
 246             | "pthread_mutex_lock"
 247             | "pthread_mutex_unlock"
 248             | "pthread_mutex_destroy"
 249             | "pthread_rwlock_rdlock"
 250             | "pthread_rwlock_unlock"
 251             | "pthread_rwlock_wrlock"
 252             | "pthread_rwlock_destroy"
 253             | "pthread_condattr_init"
 254             | "pthread_condattr_setclock"
 255             | "pthread_cond_init"
 256             | "pthread_condattr_destroy"
 257             | "pthread_cond_destroy"
 258             => {
 259                 this.write_null(dest)?;
 260             }
 261
 262             // We don't support fork so we don't have to do anything for atfork.
 263             "pthread_atfork" => {
 264                 this.write_null(dest)?;
 265             }
 266
 267             // Some things needed for `sys::thread` initialization to go through.
 268             | "signal"
 269             | "sigaction"
 270             | "sigaltstack"
 271             => {
 272                 this.write_scalar(Scalar::from_int(0, dest.layout.size), dest)?;
 273             }
 274
 275             "sysconf" => {
 276                 let name = this.read_scalar(args[0])?.to_i32()?;
 277
 278                 trace!("sysconf() called with name {}", name);
 279                 // TODO: Cache the sysconf integers via Miri's global cache.
 280                 let paths = &[
 281                     (&["libc", "_SC_PAGESIZE"], Scalar::from_int(PAGE_SIZE, dest.layout.size)),
 282                     (&["libc", "_SC_GETPW_R_SIZE_MAX"], Scalar::from_int(-1, dest.layout.size)),
 283                     (
 284                         &["libc", "_SC_NPROCESSORS_ONLN"],
 285                         Scalar::from_int(NUM_CPUS, dest.layout.size),
 286                     ),
 287                 ];
 288                 let mut result = None;
 289                 for &(path, path_value) in paths {
 290                     if let Some(val) = this.eval_path_scalar(path)? {
 291                         let val = val.to_i32()?;
 292                         if val == name {
 293                             result = Some(path_value);
 294                             break;
 295                         }
 296                     }
 297                 }
 298                 if let Some(result) = result {
 299                     this.write_scalar(result, dest)?;
 300                 } else {
 301                     throw_unsup_format!("Unimplemented sysconf name: {}", name)
 302                 }
 303             }
 304
 305             "isatty" => {
 306                 this.write_null(dest)?;
 307             }
 308
 309             "posix_fadvise" => {
 310                 // fadvise is only informational, we can ignore it.
 311                 this.write_null(dest)?;
 312             }
 313
 314             "mmap" => {
 315                 // 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.
 316                 let addr = this.read_scalar(args[0])?.not_undef()?;
 317                 this.write_scalar(addr, dest)?;
 318             }
 319
 320             "mprotect" => {
 321                 this.write_null(dest)?;
 322             }
 323
 324             _ => {
 325                 match this.tcx.sess.target.target.target_os.as_str() {
 326                     "linux" => return linux::EvalContextExt::emulate_foreign_item_by_name(this, link_name, args, dest, ret),
 327                     "macos" => return macos::EvalContextExt::emulate_foreign_item_by_name(this, link_name, args, dest, ret),
 328                     _ => unreachable!(),
 329                 }
 330             }
 331         };
 332
 333         Ok(true)
 334     }
 335 }