src/shims/dlsym.rs

   1 use rustc_middle::mir;
   2
   3 use crate::*;
   4 use helpers::check_arg_count;
   5
   6 #[derive(Debug, Copy, Clone)]
   7 pub enum Dlsym {
   8     GetEntropy,
   9 }
  10
  11 impl Dlsym {
  12     // Returns an error for unsupported symbols, and None if this symbol
  13     // should become a NULL pointer (pretend it does not exist).
  14     pub fn from_str(name: &[u8], target_os: &str) -> InterpResult<'static, Option<Dlsym>> {
  15         use self::Dlsym::*;
  16         let name = String::from_utf8_lossy(name);
  17         Ok(match target_os {
  18             "linux" => match &*name {
  19                 "__pthread_get_minstack" => None,
  20                 _ => throw_unsup_format!("unsupported Linux dlsym: {}", name),
  21             }
  22             "macos" => match &*name {
  23                 "getentropy" => Some(GetEntropy),
  24                 _ => throw_unsup_format!("unsupported macOS dlsym: {}", name),
  25             }
  26             "windows" => match &*name {
  27                 "SetThreadStackGuarantee" => None,
  28                 "AcquireSRWLockExclusive" => None,
  29                 "GetSystemTimePreciseAsFileTime" => None,
  30                 _ => throw_unsup_format!("unsupported Windows dlsym: {}", name),
  31             }
  32             os => bug!("dlsym not implemented for target_os {}", os),
  33         })
  34     }
  35 }
  36
  37 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  38 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  39     fn call_dlsym(
  40         &mut self,
  41         dlsym: Dlsym,
  42         args: &[OpTy<'tcx, Tag>],
  43         ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
  44     ) -> InterpResult<'tcx> {
  45         use self::Dlsym::*;
  46
  47         let this = self.eval_context_mut();
  48         let (dest, ret) = ret.expect("we don't support any diverging dlsym");
  49
  50         match dlsym {
  51             GetEntropy => {
  52                 let &[ptr, len] = check_arg_count(args)?;
  53                 let ptr = this.read_scalar(ptr)?.not_undef()?;
  54                 let len = this.read_scalar(len)?.to_machine_usize(this)?;
  55                 this.gen_random(ptr, len)?;
  56                 this.write_null(dest)?;
  57             }
  58         }
  59
  60         this.dump_place(*dest);
  61         this.go_to_block(ret);
  62         Ok(())
  63     }
  64 }