diff options
Diffstat (limited to 'rust/qemu-api/src')
| -rw-r--r-- | rust/qemu-api/src/c_str.rs | 53 | ||||
| -rw-r--r-- | rust/qemu-api/src/lib.rs | 1 | ||||
| -rw-r--r-- | rust/qemu-api/src/vmstate.rs | 2 |
3 files changed, 55 insertions, 1 deletions
diff --git a/rust/qemu-api/src/c_str.rs b/rust/qemu-api/src/c_str.rs new file mode 100644 index 0000000..4cd96da --- /dev/null +++ b/rust/qemu-api/src/c_str.rs @@ -0,0 +1,53 @@ +// Copyright 2024 Red Hat, Inc. +// Author(s): Paolo Bonzini <pbonzini@redhat.com> +// SPDX-License-Identifier: GPL-2.0-or-later + +#[macro_export] +/// Given a string constant _without_ embedded or trailing NULs, return +/// a `CStr`. +/// +/// Needed for compatibility with Rust <1.77. +macro_rules! c_str { + ($str:expr) => {{ + const STRING: &str = concat!($str, "\0"); + const BYTES: &[u8] = STRING.as_bytes(); + + // "for" is not allowed in const context... oh well, + // everybody loves some lisp. This could be turned into + // a procedural macro if this is a problem; alternatively + // Rust 1.72 makes CStr::from_bytes_with_nul a const function. + const fn f(b: &[u8], i: usize) { + if i == b.len() - 1 { + } else if b[i] == 0 { + panic!("c_str argument contains NUL") + } else { + f(b, i + 1) + } + } + f(BYTES, 0); + + // SAFETY: absence of NULs apart from the final byte was checked above + unsafe { std::ffi::CStr::from_bytes_with_nul_unchecked(BYTES) } + }}; +} + +#[cfg(test)] +mod tests { + use std::ffi::CStr; + + use crate::c_str; + + #[test] + fn test_cstr_macro() { + let good = c_str!("🦀"); + let good_bytes = b"\xf0\x9f\xa6\x80\0"; + assert_eq!(good.to_bytes_with_nul(), good_bytes); + } + + #[test] + fn test_cstr_macro_const() { + const GOOD: &CStr = c_str!("🦀"); + const GOOD_BYTES: &[u8] = b"\xf0\x9f\xa6\x80\0"; + assert_eq!(GOOD.to_bytes_with_nul(), GOOD_BYTES); + } +} diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs index ed840ee..e6bd953 100644 --- a/rust/qemu-api/src/lib.rs +++ b/rust/qemu-api/src/lib.rs @@ -29,6 +29,7 @@ unsafe impl Sync for bindings::VMStateDescription {} unsafe impl Sync for bindings::VMStateField {} unsafe impl Sync for bindings::VMStateInfo {} +pub mod c_str; pub mod definitions; pub mod device_class; pub mod vmstate; diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs index 4e06e40..9c252ce 100644 --- a/rust/qemu-api/src/vmstate.rs +++ b/rust/qemu-api/src/vmstate.rs @@ -15,7 +15,7 @@ macro_rules! vmstate_unused_buffer { ($field_exists_fn:expr, $version_id:expr, $size:expr) => {{ $crate::bindings::VMStateField { - name: c"unused".as_ptr(), + name: c_str!("unused").as_ptr(), err_hint: ::core::ptr::null(), offset: 0, size: $size, |