src/shims/foreign_items/posix.rs

   1 mod linux;
   2 mod macos;
   3
   4 use std::convert::TryFrom;
   5
   6 use log::trace;
   7
   8 use crate::*;
   9 use rustc_middle::mir;
  10 use rustc_target::abi::{Align, LayoutOf, Size};
  11
  12 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  13 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  14     fn emulate_foreign_item_by_name(
  15         &mut self,
  16         link_name: &str,
  17         args: &[OpTy<'tcx, Tag>],
  18         dest: PlaceTy<'tcx, Tag>,
  19         ret: mir::BasicBlock,
  20     ) -> InterpResult<'tcx, bool> {
  21         let this = self.eval_context_mut();
  22
  23         match link_name {
  24             // Environment related shims
  25             "getenv" => {
  26                 let result = this.getenv(args[0])?;
  27                 this.write_scalar(result, dest)?;
  28             }
  29             "unsetenv" => {
  30                 let result = this.unsetenv(args[0])?;
  31                 this.write_scalar(Scalar::from_i32(result), dest)?;
  32             }
  33             "setenv" => {
  34                 let result = this.setenv(args[0], args[1])?;
  35                 this.write_scalar(Scalar::from_i32(result), dest)?;
  36             }
  37             "getcwd" => {
  38                 let result = this.getcwd(args[0], args[1])?;
  39                 this.write_scalar(result, dest)?;
  40             }
  41             "chdir" => {
  42                 let result = this.chdir(args[0])?;
  43                 this.write_scalar(Scalar::from_i32(result), dest)?;
  44             }
  45
  46             // File related shims
  47             "open" | "open64" => {
  48                 let result = this.open(args[0], args[1])?;
  49                 this.write_scalar(Scalar::from_i32(result), dest)?;
  50             }
  51             "fcntl" => {
  52                 let result = this.fcntl(args[0], args[1], args.get(2).cloned())?;
  53                 this.write_scalar(Scalar::from_i32(result), dest)?;
  54             }
  55             "read" => {
  56                 let result = this.read(args[0], args[1], args[2])?;
  57                 this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
  58             }
  59             "write" => {
  60                 let fd = this.read_scalar(args[0])?.to_i32()?;
  61                 let buf = this.read_scalar(args[1])?.not_undef()?;
  62                 let n = this.read_scalar(args[2])?.to_machine_usize(this)?;
  63                 trace!("Called write({:?}, {:?}, {:?})", fd, buf, n);
  64                 let result = if fd == 1 || fd == 2 {
  65                     // stdout/stderr
  66                     use std::io::{self, Write};
  67
  68                     let buf_cont = this.memory.read_bytes(buf, Size::from_bytes(n))?;
  69                     // We need to flush to make sure this actually appears on the screen
  70                     let res = if fd == 1 {
  71                         // Stdout is buffered, flush to make sure it appears on the screen.
  72                         // This is the write() syscall of the interpreted program, we want it
  73                         // to correspond to a write() syscall on the host -- there is no good
  74                         // in adding extra buffering here.
  75                         let res = io::stdout().write(buf_cont);
  76                         io::stdout().flush().unwrap();
  77                         res
  78                     } else {
  79                         // No need to flush, stderr is not buffered.
  80                         io::stderr().write(buf_cont)
  81                     };
  82                     match res {
  83                         Ok(n) => i64::try_from(n).unwrap(),
  84                         Err(_) => -1,
  85                     }
  86                 } else {
  87                     this.write(args[0], args[1], args[2])?
  88                 };
  89                 // Now, `result` is the value we return back to the program.
  90                 this.write_scalar(Scalar::from_machine_isize(result, this), dest)?;
  91             }
  92             "unlink" => {
  93                 let result = this.unlink(args[0])?;
  94                 this.write_scalar(Scalar::from_i32(result), dest)?;
  95             }
  96             "symlink" => {
  97                 let result = this.symlink(args[0], args[1])?;
  98                 this.write_scalar(Scalar::from_i32(result), dest)?;
  99             }
 100             "rename" => {
 101                 let result = this.rename(args[0], args[1])?;
 102                 this.write_scalar(Scalar::from_i32(result), dest)?;
 103             }
 104             "mkdir" => {
 105                 let result = this.mkdir(args[0], args[1])?;
 106                 this.write_scalar(Scalar::from_i32(result), dest)?;
 107             }
 108             "rmdir" => {
 109                 let result = this.rmdir(args[0])?;
 110                 this.write_scalar(Scalar::from_i32(result), dest)?;
 111             }
 112             "closedir" => {
 113                 let result = this.closedir(args[0])?;
 114                 this.write_scalar(Scalar::from_i32(result), dest)?;
 115             }
 116             "lseek" | "lseek64" => {
 117                 let result = this.lseek64(args[0], args[1], args[2])?;
 118                 // "lseek" is only used on macOS which is 64bit-only, so `i64` always works.
 119                 this.write_scalar(Scalar::from_i64(result), dest)?;
 120             }
 121
 122             // Allocation
 123             "posix_memalign" => {
 124                 let ret = this.deref_operand(args[0])?;
 125                 let align = this.read_scalar(args[1])?.to_machine_usize(this)?;
 126                 let size = this.read_scalar(args[2])?.to_machine_usize(this)?;
 127                 // Align must be power of 2, and also at least ptr-sized (POSIX rules).
 128                 if !align.is_power_of_two() {
 129                     throw_ub_format!("posix_memalign: alignment must be a power of two, but is {}", align);
 130                 }
 131                 if align < this.pointer_size().bytes() {
 132                     throw_ub_format!(
 133                         "posix_memalign: alignment must be at least the size of a pointer, but is {}",
 134                         align,
 135                     );
 136                 }
 137
 138                 if size == 0 {
 139                     this.write_null(ret.into())?;
 140                 } else {
 141                     let ptr = this.memory.allocate(
 142                         Size::from_bytes(size),
 143                         Align::from_bytes(align).unwrap(),
 144                         MiriMemoryKind::C.into(),
 145                     );
 146                     this.write_scalar(ptr, ret.into())?;
 147                 }
 148                 this.write_null(dest)?;
 149             }
 150
 151             // Dynamic symbol loading
 152             "dlsym" => {
 153                 let _handle = this.read_scalar(args[0])?;
 154                 let symbol = this.read_scalar(args[1])?.not_undef()?;
 155                 let symbol_name = this.memory.read_c_str(symbol)?;
 156                 let err = format!("bad c unicode symbol: {:?}", symbol_name);
 157                 let symbol_name = ::std::str::from_utf8(symbol_name).unwrap_or(&err);
 158                 if let Some(dlsym) = Dlsym::from_str(symbol_name)? {
 159                     let ptr = this.memory.create_fn_alloc(FnVal::Other(dlsym));
 160                     this.write_scalar(Scalar::from(ptr), dest)?;
 161                 } else {
 162                     this.write_null(dest)?;
 163                 }
 164             }
 165
 166             // Querying system information
 167             "sysconf" => {
 168                 let name = this.read_scalar(args[0])?.to_i32()?;
 169
 170                 let sysconfs = &[
 171                     ("_SC_PAGESIZE", Scalar::from_int(PAGE_SIZE, this.pointer_size())),
 172                     ("_SC_NPROCESSORS_ONLN", Scalar::from_int(NUM_CPUS, this.pointer_size())),
 173                 ];
 174                 let mut result = None;
 175                 for &(sysconf_name, value) in sysconfs {
 176                     let sysconf_name = this.eval_libc_i32(sysconf_name)?;
 177                     if sysconf_name == name {
 178                         result = Some(value);
 179                         break;
 180                     }
 181                 }
 182                 if let Some(result) = result {
 183                     this.write_scalar(result, dest)?;
 184                 } else {
 185                     throw_unsup_format!("unimplemented sysconf name: {}", name)
 186                 }
 187             }
 188
 189             // Thread-local storage
 190             "pthread_key_create" => {
 191                 let key_place = this.deref_operand(args[0])?;
 192
 193                 // Extract the function type out of the signature (that seems easier than constructing it ourselves).
 194                 let dtor = match this.test_null(this.read_scalar(args[1])?.not_undef()?)? {
 195                     Some(dtor_ptr) => Some(this.memory.get_fn(dtor_ptr)?.as_instance()?),
 196                     None => None,
 197                 };
 198
 199                 // Figure out how large a pthread TLS key actually is.
 200                 // To this end, deref the argument type. This is `libc::pthread_key_t`.
 201                 let key_type = args[0].layout.ty
 202                     .builtin_deref(true)
 203                     .ok_or_else(|| err_ub_format!(
 204                         "wrong signature used for `pthread_key_create`: first argument must be a raw pointer."
 205                     ))?
 206                     .ty;
 207                 let key_layout = this.layout_of(key_type)?;
 208
 209                 // Create key and write it into the memory where `key_ptr` wants it.
 210                 let key = this.machine.tls.create_tls_key(dtor, key_layout.size)?;
 211                 this.write_scalar(Scalar::from_uint(key, key_layout.size), key_place.into())?;
 212
 213                 // Return success (`0`).
 214                 this.write_null(dest)?;
 215             }
 216             "pthread_key_delete" => {
 217                 let key = this.force_bits(this.read_scalar(args[0])?.not_undef()?, args[0].layout.size)?;
 218                 this.machine.tls.delete_tls_key(key)?;
 219                 // Return success (0)
 220                 this.write_null(dest)?;
 221             }
 222             "pthread_getspecific" => {
 223                 let key = this.force_bits(this.read_scalar(args[0])?.not_undef()?, args[0].layout.size)?;
 224                 let active_thread = this.get_active_thread()?;
 225                 let ptr = this.machine.tls.load_tls(key, active_thread, this)?;
 226                 this.write_scalar(ptr, dest)?;
 227             }
 228             "pthread_setspecific" => {
 229                 let key = this.force_bits(this.read_scalar(args[0])?.not_undef()?, args[0].layout.size)?;
 230                 let active_thread = this.get_active_thread()?;
 231                 let new_ptr = this.read_scalar(args[1])?.not_undef()?;
 232                 this.machine.tls.store_tls(key, active_thread, this.test_null(new_ptr)?)?;
 233
 234                 // Return success (`0`).
 235                 this.write_null(dest)?;
 236             }
 237
 238             // Synchronization primitives
 239             "pthread_mutexattr_init" => {
 240                 let result = this.pthread_mutexattr_init(args[0])?;
 241                 this.write_scalar(Scalar::from_i32(result), dest)?;
 242             }
 243             "pthread_mutexattr_settype" => {
 244                 let result = this.pthread_mutexattr_settype(args[0], args[1])?;
 245                 this.write_scalar(Scalar::from_i32(result), dest)?;
 246             }
 247             "pthread_mutexattr_destroy" => {
 248                 let result = this.pthread_mutexattr_destroy(args[0])?;
 249                 this.write_scalar(Scalar::from_i32(result), dest)?;
 250             }
 251             "pthread_mutex_init" => {
 252                 let result = this.pthread_mutex_init(args[0], args[1])?;
 253                 this.write_scalar(Scalar::from_i32(result), dest)?;
 254             }
 255             "pthread_mutex_lock" => {
 256                 let result = this.pthread_mutex_lock(args[0])?;
 257                 this.write_scalar(Scalar::from_i32(result), dest)?;
 258             }
 259             "pthread_mutex_trylock" => {
 260                 let result = this.pthread_mutex_trylock(args[0])?;
 261                 this.write_scalar(Scalar::from_i32(result), dest)?;
 262             }
 263             "pthread_mutex_unlock" => {
 264                 let result = this.pthread_mutex_unlock(args[0])?;
 265                 this.write_scalar(Scalar::from_i32(result), dest)?;
 266             }
 267             "pthread_mutex_destroy" => {
 268                 let result = this.pthread_mutex_destroy(args[0])?;
 269                 this.write_scalar(Scalar::from_i32(result), dest)?;
 270             }
 271             "pthread_rwlock_rdlock" => {
 272                 let result = this.pthread_rwlock_rdlock(args[0])?;
 273                 this.write_scalar(Scalar::from_i32(result), dest)?;
 274             }
 275             "pthread_rwlock_tryrdlock" => {
 276                 let result = this.pthread_rwlock_tryrdlock(args[0])?;
 277                 this.write_scalar(Scalar::from_i32(result), dest)?;
 278             }
 279             "pthread_rwlock_wrlock" => {
 280                 let result = this.pthread_rwlock_wrlock(args[0])?;
 281                 this.write_scalar(Scalar::from_i32(result), dest)?;
 282             }
 283             "pthread_rwlock_trywrlock" => {
 284                 let result = this.pthread_rwlock_trywrlock(args[0])?;
 285                 this.write_scalar(Scalar::from_i32(result), dest)?;
 286             }
 287             "pthread_rwlock_unlock" => {
 288                 let result = this.pthread_rwlock_unlock(args[0])?;
 289                 this.write_scalar(Scalar::from_i32(result), dest)?;
 290             }
 291             "pthread_rwlock_destroy" => {
 292                 let result = this.pthread_rwlock_destroy(args[0])?;
 293                 this.write_scalar(Scalar::from_i32(result), dest)?;
 294             }
 295
 296             // Threading
 297             "pthread_create" => {
 298                 assert_eq!(args.len(), 4);
 299                 let result = this.pthread_create(args[0], args[1], args[2], args[3])?;
 300                 this.write_scalar(Scalar::from_i32(result), dest)?;
 301             }
 302             "pthread_join" => {
 303                 assert_eq!(args.len(), 2);
 304                 let result = this.pthread_join(args[0], args[1])?;
 305                 this.write_scalar(Scalar::from_i32(result), dest)?;
 306             }
 307             "pthread_detach" => {
 308                 assert_eq!(args.len(), 1);
 309                 let result = this.pthread_detach(args[0])?;
 310                 this.write_scalar(Scalar::from_i32(result), dest)?;
 311             }
 312             "pthread_self" => {
 313                 assert_eq!(args.len(), 0);
 314                 this.pthread_self(dest)?;
 315             }
 316             "prctl" => {
 317                 assert_eq!(args.len(), 5);
 318                 let result = this.prctl(args[0], args[1], args[2], args[3], args[4])?;
 319                 this.write_scalar(Scalar::from_i32(result), dest)?;
 320             }
 321
 322             // Miscellaneous
 323             "isatty" => {
 324                 let _fd = this.read_scalar(args[0])?.to_i32()?;
 325                 // "returns 1 if fd is an open file descriptor referring to a terminal; otherwise 0 is returned, and errno is set to indicate the error"
 326                 // FIXME: we just say nothing is a terminal.
 327                 let enotty = this.eval_libc("ENOTTY")?;
 328                 this.set_last_error(enotty)?;
 329                 this.write_null(dest)?;
 330             }
 331             "pthread_atfork" => {
 332                 let _prepare = this.read_scalar(args[0])?.not_undef()?;
 333                 let _parent = this.read_scalar(args[1])?.not_undef()?;
 334                 let _child = this.read_scalar(args[1])?.not_undef()?;
 335                 // We do not support forking, so there is nothing to do here.
 336                 this.write_null(dest)?;
 337             }
 338
 339             // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
 340             // These shims are enabled only when the caller is in the standard library.
 341             | "pthread_attr_init"
 342             | "pthread_attr_destroy"
 343             | "pthread_attr_setstacksize"
 344             | "pthread_condattr_init"
 345             | "pthread_condattr_setclock"
 346             | "pthread_cond_init"
 347             | "pthread_condattr_destroy"
 348             | "pthread_cond_destroy" if this.frame().instance.to_string().starts_with("std::sys::unix::")
 349             => {
 350                 this.write_null(dest)?;
 351             }
 352             "pthread_attr_getguardsize" if this.frame().instance.to_string().starts_with("std::sys::unix::")
 353             => {
 354                 let guard_size = this.deref_operand(args[1])?;
 355                 let guard_size_layout = this.libc_ty_layout("size_t")?;
 356                 this.write_scalar(Scalar::from_uint(crate::PAGE_SIZE, guard_size_layout.size), guard_size.into())?;
 357
 358                 // Return success (`0`).
 359                 this.write_null(dest)?;
 360             }
 361
 362             | "signal"
 363             | "sigaction"
 364             | "sigaltstack"
 365             | "mprotect" if this.frame().instance.to_string().starts_with("std::sys::unix::")
 366             => {
 367                 this.write_null(dest)?;
 368             }
 369
 370             // Platform-specific shims
 371             _ => {
 372                 match this.tcx.sess.target.target.target_os.as_str() {
 373                     "linux" => return linux::EvalContextExt::emulate_foreign_item_by_name(this, link_name, args, dest, ret),
 374                     "macos" => return macos::EvalContextExt::emulate_foreign_item_by_name(this, link_name, args, dest, ret),
 375                     _ => unreachable!(),
 376                 }
 377             }
 378         };
 379
 380         Ok(true)
 381     }
 382 }