src/tools/miri/src/shims/unix/linux/foreign_items.rs

   1 use rustc_span::Symbol;
   2 use rustc_target::spec::abi::Abi;
   3
   4 use crate::machine::SIGRTMAX;
   5 use crate::*;
   6 use shims::foreign_items::EmulateByNameResult;
   7 use shims::unix::fs::EvalContextExt as _;
   8 use shims::unix::linux::fd::EvalContextExt as _;
   9 use shims::unix::linux::sync::futex;
  10 use shims::unix::sync::EvalContextExt as _;
  11 use shims::unix::thread::EvalContextExt as _;
  12
  13 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriInterpCx<'mir, 'tcx> {}
  14 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriInterpCxExt<'mir, 'tcx> {
  15     fn emulate_foreign_item_by_name(
  16         &mut self,
  17         link_name: Symbol,
  18         abi: Abi,
  19         args: &[OpTy<'tcx, Provenance>],
  20         dest: &PlaceTy<'tcx, Provenance>,
  21     ) -> InterpResult<'tcx, EmulateByNameResult<'mir, 'tcx>> {
  22         let this = self.eval_context_mut();
  23
  24         // See `fn emulate_foreign_item_by_name` in `shims/foreign_items.rs` for the general pattern.
  25
  26         match link_name.as_str() {
  27             // errno
  28             "__errno_location" => {
  29                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  30                 let errno_place = this.last_error_place()?;
  31                 this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
  32             }
  33
  34             // File related shims (but also see "syscall" below for statx)
  35             "readdir64" => {
  36                 let [dirp] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  37                 let result = this.linux_readdir64(dirp)?;
  38                 this.write_scalar(result, dest)?;
  39             }
  40             // Linux-only
  41             "sync_file_range" => {
  42                 let [fd, offset, nbytes, flags] =
  43                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  44                 let result = this.sync_file_range(fd, offset, nbytes, flags)?;
  45                 this.write_scalar(result, dest)?;
  46             }
  47             "epoll_create1" => {
  48                 let [flag] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  49                 let result = this.epoll_create1(flag)?;
  50                 this.write_scalar(result, dest)?;
  51             }
  52             "epoll_ctl" => {
  53                 let [epfd, op, fd, event] =
  54                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  55                 let result = this.epoll_ctl(epfd, op, fd, event)?;
  56                 this.write_scalar(result, dest)?;
  57             }
  58             "eventfd" => {
  59                 let [val, flag] =
  60                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  61                 let result = this.eventfd(val, flag)?;
  62                 this.write_scalar(result, dest)?;
  63             }
  64             "socketpair" => {
  65                 let [domain, type_, protocol, sv] =
  66                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  67
  68                 let result = this.socketpair(domain, type_, protocol, sv)?;
  69                 this.write_scalar(result, dest)?;
  70             }
  71             "__libc_current_sigrtmax" => {
  72                 let [] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  73
  74                 this.write_scalar(Scalar::from_i32(SIGRTMAX), dest)?;
  75             }
  76
  77             // Threading
  78             "pthread_condattr_setclock" => {
  79                 let [attr, clock_id] =
  80                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  81                 let result = this.pthread_condattr_setclock(attr, clock_id)?;
  82                 this.write_scalar(result, dest)?;
  83             }
  84             "pthread_condattr_getclock" => {
  85                 let [attr, clock_id] =
  86                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  87                 let result = this.pthread_condattr_getclock(attr, clock_id)?;
  88                 this.write_scalar(result, dest)?;
  89             }
  90             "pthread_setname_np" => {
  91                 let [thread, name] =
  92                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
  93                 let max_len = 16;
  94                 let res = this.pthread_setname_np(
  95                     this.read_scalar(thread)?,
  96                     this.read_scalar(name)?,
  97                     max_len,
  98                 )?;
  99                 this.write_scalar(res, dest)?;
 100             }
 101             "pthread_getname_np" => {
 102                 let [thread, name, len] =
 103                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 104                 let res = this.pthread_getname_np(
 105                     this.read_scalar(thread)?,
 106                     this.read_scalar(name)?,
 107                     this.read_scalar(len)?,
 108                 )?;
 109                 this.write_scalar(res, dest)?;
 110             }
 111
 112             // Dynamically invoked syscalls
 113             "syscall" => {
 114                 // We do not use `check_shim` here because `syscall` is variadic. The argument
 115                 // count is checked bellow.
 116                 this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
 117                 // The syscall variadic function is legal to call with more arguments than needed,
 118                 // extra arguments are simply ignored. The important check is that when we use an
 119                 // argument, we have to also check all arguments *before* it to ensure that they
 120                 // have the right type.
 121
 122                 let sys_getrandom = this.eval_libc("SYS_getrandom").to_machine_usize(this)?;
 123
 124                 let sys_statx = this.eval_libc("SYS_statx").to_machine_usize(this)?;
 125
 126                 let sys_futex = this.eval_libc("SYS_futex").to_machine_usize(this)?;
 127
 128                 if args.is_empty() {
 129                     throw_ub_format!(
 130                         "incorrect number of arguments for syscall: got 0, expected at least 1"
 131                     );
 132                 }
 133                 match this.read_machine_usize(&args[0])? {
 134                     // `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
 135                     // is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
 136                     id if id == sys_getrandom => {
 137                         // The first argument is the syscall id, so skip over it.
 138                         if args.len() < 4 {
 139                             throw_ub_format!(
 140                                 "incorrect number of arguments for `getrandom` syscall: got {}, expected at least 4",
 141                                 args.len()
 142                             );
 143                         }
 144                         getrandom(this, &args[1], &args[2], &args[3], dest)?;
 145                     }
 146                     // `statx` is used by `libstd` to retrieve metadata information on `linux`
 147                     // instead of using `stat`,`lstat` or `fstat` as on `macos`.
 148                     id if id == sys_statx => {
 149                         // The first argument is the syscall id, so skip over it.
 150                         if args.len() < 6 {
 151                             throw_ub_format!(
 152                                 "incorrect number of arguments for `statx` syscall: got {}, expected at least 6",
 153                                 args.len()
 154                             );
 155                         }
 156                         let result =
 157                             this.linux_statx(&args[1], &args[2], &args[3], &args[4], &args[5])?;
 158                         this.write_scalar(Scalar::from_machine_isize(result.into(), this), dest)?;
 159                     }
 160                     // `futex` is used by some synchonization primitives.
 161                     id if id == sys_futex => {
 162                         futex(this, &args[1..], dest)?;
 163                     }
 164                     id => {
 165                         this.handle_unsupported(format!("can't execute syscall with ID {id}"))?;
 166                         return Ok(EmulateByNameResult::AlreadyJumped);
 167                     }
 168                 }
 169             }
 170
 171             // Miscelanneous
 172             "getrandom" => {
 173                 let [ptr, len, flags] =
 174                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 175                 getrandom(this, ptr, len, flags, dest)?;
 176             }
 177             "sched_getaffinity" => {
 178                 let [pid, cpusetsize, mask] =
 179                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 180                 this.read_scalar(pid)?.to_i32()?;
 181                 this.read_machine_usize(cpusetsize)?;
 182                 this.deref_operand(mask)?;
 183                 // FIXME: we just return an error; `num_cpus` then falls back to `sysconf`.
 184                 let einval = this.eval_libc("EINVAL");
 185                 this.set_last_error(einval)?;
 186                 this.write_scalar(Scalar::from_i32(-1), dest)?;
 187             }
 188
 189             // Incomplete shims that we "stub out" just to get pre-main initialization code to work.
 190             // These shims are enabled only when the caller is in the standard library.
 191             "pthread_getattr_np" if this.frame_in_std() => {
 192                 let [_thread, _attr] =
 193                     this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
 194                 this.write_null(dest)?;
 195             }
 196
 197             _ => return Ok(EmulateByNameResult::NotSupported),
 198         };
 199
 200         Ok(EmulateByNameResult::NeedsJumping)
 201     }
 202 }
 203
 204 // Shims the linux `getrandom` syscall.
 205 fn getrandom<'tcx>(
 206     this: &mut MiriInterpCx<'_, 'tcx>,
 207     ptr: &OpTy<'tcx, Provenance>,
 208     len: &OpTy<'tcx, Provenance>,
 209     flags: &OpTy<'tcx, Provenance>,
 210     dest: &PlaceTy<'tcx, Provenance>,
 211 ) -> InterpResult<'tcx> {
 212     let ptr = this.read_pointer(ptr)?;
 213     let len = this.read_machine_usize(len)?;
 214
 215     // The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
 216     // neither of which have any effect on our current PRNG.
 217     // See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
 218     let _flags = this.read_scalar(flags)?.to_i32();
 219
 220     this.gen_random(ptr, len)?;
 221     this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;
 222     Ok(())
 223 }