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precise getrandom return type and align_offset arithmetic

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This commit is contained in:
Ralf Jung 2020-03-28 17:47:00 +01:00
parent b7fec6b17f
commit d6795a77b4
2 changed files with 4 additions and 4 deletions
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2
src/shims/foreign_items/posix/linux.rs
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@ -140,6 +140,6 @@ fn getrandom<'tcx>(
let _flags = this.read_scalar(args[2])?.to_i32()?; let _flags = this.read_scalar(args[2])?.to_i32()?;
this.gen_random(ptr, len)?; this.gen_random(ptr, len)?;
this.write_scalar(Scalar::from_uint(len, dest.layout.size), dest)?; this.write_scalar(Scalar::from_machine_usize(len, this), dest)?;
Ok(()) Ok(())
} }

6
src/shims/mod.rs
View File

@ -75,7 +75,7 @@ fn align_offset(
let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?; let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
// Default: no result. // Default: no result.
let mut result = this.truncate(u128::MAX, dest.layout); let mut result = this.usize_max();
if let Ok(ptr) = this.force_ptr(ptr_scalar) { if let Ok(ptr) = this.force_ptr(ptr_scalar) {
// Only do anything if we can identify the allocation this goes to. // Only do anything if we can identify the allocation this goes to.
let cur_align = let cur_align =
@ -84,7 +84,7 @@ fn align_offset(
// If the allocation alignment is at least the required alignment we use the // If the allocation alignment is at least the required alignment we use the
// libcore implementation. // libcore implementation.
// FIXME: is this correct in case of truncation? // FIXME: is this correct in case of truncation?
result = u128::try_from( result = u64::try_from(
(this.force_bits(ptr_scalar, this.pointer_size())? as *const i8) (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
.align_offset(usize::try_from(req_align).unwrap()) .align_offset(usize::try_from(req_align).unwrap())
).unwrap(); ).unwrap();
@ -92,7 +92,7 @@ fn align_offset(
} }
// Return result, and jump to caller. // Return result, and jump to caller.
this.write_scalar(Scalar::from_uint(result, this.pointer_size()), dest)?; this.write_scalar(Scalar::from_machine_usize(result, this), dest)?;
this.go_to_block(ret); this.go_to_block(ret);
Ok(()) Ok(())
} }