diff options
author | Stefan Hajnoczi <stefanha@redhat.com> | 2025-06-06 09:42:58 -0400 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2025-06-06 09:42:59 -0400 |
commit | 96215036f47403438c7c7869b7cd419bd7a11f82 (patch) | |
tree | 6988fd2516ba3d03c6d01529b155039a2056bf72 /rust | |
parent | fc8da54ec43cf6302ac496d8fe54832812954679 (diff) | |
parent | 3f9bdfb0dc8162cbc080c868625336178ddcda56 (diff) | |
download | qemu-master.zip qemu-master.tar.gz qemu-master.tar.bz2 |
* futex: support Windows
* qemu-thread: Avoid futex abstraction for non-Linux
* migration, hw/display/apple-gfx: replace QemuSemaphore with QemuEvent
* rust: bindings for Error
* hpet, rust/hpet: return errors from realize if properties are incorrect
* rust/hpet: Drop BqlCell wrapper for num_timers
* target/i386: Emulate ftz and denormal flag bits correctly
* i386/kvm: Prefault memory on page state change
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# gpg: Signature made Fri 06 Jun 2025 08:33:12 EDT
# gpg: using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg: issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg: aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4 E2F7 7E15 100C CD36 69B1
# Subkey fingerprint: F133 3857 4B66 2389 866C 7682 BFFB D25F 78C7 AE83
* tag 'for-upstream' of https://gitlab.com/bonzini/qemu: (31 commits)
tests/tcg/x86_64/fma: add test for exact-denormal output
target/i386: Wire up MXCSR.DE and FPUS.DE correctly
target/i386: Use correct type for get_float_exception_flags() values
target/i386: Detect flush-to-zero after rounding
hw/display/apple-gfx: Replace QemuSemaphore with QemuEvent
migration/postcopy: Replace QemuSemaphore with QemuEvent
migration/colo: Replace QemuSemaphore with QemuEvent
migration: Replace QemuSemaphore with QemuEvent
qemu-thread: Document QemuEvent
qemu-thread: Use futex if available for QemuLockCnt
qemu-thread: Use futex for QemuEvent on Windows
qemu-thread: Avoid futex abstraction for non-Linux
qemu-thread: Replace __linux__ with CONFIG_LINUX
futex: Support Windows
futex: Check value after qemu_futex_wait()
i386/kvm: Prefault memory on page state change
rust: make TryFrom macro more resilient
docs: update Rust module status
rust/hpet: Drop BqlCell wrapper for num_timers
rust/hpet: return errors from realize if properties are incorrect
...
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'rust')
-rw-r--r-- | rust/Cargo.lock | 17 | ||||
-rw-r--r-- | rust/Cargo.toml | 1 | ||||
-rw-r--r-- | rust/hw/char/pl011/src/device.rs | 5 | ||||
-rw-r--r-- | rust/hw/timer/hpet/src/device.rs | 62 | ||||
-rw-r--r-- | rust/hw/timer/hpet/src/fw_cfg.rs | 7 | ||||
-rw-r--r-- | rust/meson.build | 4 | ||||
-rw-r--r-- | rust/qemu-api-macros/src/lib.rs | 7 | ||||
-rw-r--r-- | rust/qemu-api/Cargo.toml | 2 | ||||
-rw-r--r-- | rust/qemu-api/meson.build | 3 | ||||
-rw-r--r-- | rust/qemu-api/src/error.rs | 416 | ||||
-rw-r--r-- | rust/qemu-api/src/lib.rs | 3 | ||||
-rw-r--r-- | rust/qemu-api/src/qdev.rs | 12 | ||||
-rw-r--r-- | rust/wrapper.h | 1 |
13 files changed, 492 insertions, 48 deletions
diff --git a/rust/Cargo.lock b/rust/Cargo.lock index bccfe85..b785c71 100644 --- a/rust/Cargo.lock +++ b/rust/Cargo.lock @@ -3,6 +3,12 @@ version = 3 [[package]] +name = "anyhow" +version = "1.0.98" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "e16d2d3311acee920a9eb8d33b8cbc1787ce4a264e85f964c2404b969bdcd487" + +[[package]] name = "arbitrary-int" version = "1.2.7" source = "registry+https://github.com/rust-lang/crates.io-index" @@ -45,6 +51,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index" checksum = "3dca9240753cf90908d7e4aac30f630662b02aebaa1b58a3cadabdb23385b58b" [[package]] +name = "foreign" +version = "0.3.1" +source = "registry+https://github.com/rust-lang/crates.io-index" +checksum = "17ca1b5be8c9d320daf386f1809c7acc0cb09accbae795c2001953fa50585846" +dependencies = [ + "libc", +] + +[[package]] name = "hpet" version = "0.1.0" dependencies = [ @@ -114,6 +129,8 @@ dependencies = [ name = "qemu_api" version = "0.1.0" dependencies = [ + "anyhow", + "foreign", "libc", "qemu_api_macros", ] diff --git a/rust/Cargo.toml b/rust/Cargo.toml index fd4c2fb..0868e1b 100644 --- a/rust/Cargo.toml +++ b/rust/Cargo.toml @@ -67,6 +67,7 @@ missing_safety_doc = "deny" mut_mut = "deny" needless_bitwise_bool = "deny" needless_pass_by_ref_mut = "deny" +needless_update = "deny" no_effect_underscore_binding = "deny" option_option = "deny" or_fun_call = "deny" diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs index 0501fa5..be8387f 100644 --- a/rust/hw/char/pl011/src/device.rs +++ b/rust/hw/char/pl011/src/device.rs @@ -175,7 +175,7 @@ impl DeviceImpl for PL011State { fn vmsd() -> Option<&'static VMStateDescription> { Some(&device_class::VMSTATE_PL011) } - const REALIZE: Option<fn(&Self)> = Some(Self::realize); + const REALIZE: Option<fn(&Self) -> qemu_api::Result<()>> = Some(Self::realize); } impl ResettablePhasesImpl for PL011State { @@ -619,9 +619,10 @@ impl PL011State { } } - fn realize(&self) { + fn realize(&self) -> qemu_api::Result<()> { self.char_backend .enable_handlers(self, Self::can_receive, Self::receive, Self::event); + Ok(()) } fn reset_hold(&self, _type: ResetType) { diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs index e3ba62b..735b2fb 100644 --- a/rust/hw/timer/hpet/src/device.rs +++ b/rust/hw/timer/hpet/src/device.rs @@ -12,7 +12,7 @@ use std::{ use qemu_api::{ bindings::{ address_space_memory, address_space_stl_le, qdev_prop_bit, qdev_prop_bool, - qdev_prop_uint32, qdev_prop_uint8, + qdev_prop_uint32, qdev_prop_usize, }, cell::{BqlCell, BqlRefCell}, irq::InterruptSource, @@ -36,9 +36,9 @@ use crate::fw_cfg::HPETFwConfig; const HPET_REG_SPACE_LEN: u64 = 0x400; // 1024 bytes /// Minimum recommended hardware implementation. -const HPET_MIN_TIMERS: u8 = 3; +const HPET_MIN_TIMERS: usize = 3; /// Maximum timers in each timer block. -const HPET_MAX_TIMERS: u8 = 32; +const HPET_MAX_TIMERS: usize = 32; /// Flags that HPETState.flags supports. const HPET_FLAG_MSI_SUPPORT_SHIFT: usize = 0; @@ -561,8 +561,8 @@ pub struct HPETState { /// HPET timer array managed by this timer block. #[doc(alias = "timer")] - timers: [BqlRefCell<HPETTimer>; HPET_MAX_TIMERS as usize], - num_timers: BqlCell<u8>, + timers: [BqlRefCell<HPETTimer>; HPET_MAX_TIMERS], + num_timers: usize, num_timers_save: BqlCell<u8>, /// Instance id (HPET timer block ID). @@ -570,11 +570,6 @@ pub struct HPETState { } impl HPETState { - // Get num_timers with `usize` type, which is useful to play with array index. - fn get_num_timers(&self) -> usize { - self.num_timers.get().into() - } - const fn has_msi_flag(&self) -> bool { self.flags & (1 << HPET_FLAG_MSI_SUPPORT_SHIFT) != 0 } @@ -636,7 +631,7 @@ impl HPETState { self.hpet_offset .set(ticks_to_ns(self.counter.get()) - CLOCK_VIRTUAL.get_ns()); - for timer in self.timers.iter().take(self.get_num_timers()) { + for timer in self.timers.iter().take(self.num_timers) { let mut t = timer.borrow_mut(); if t.is_int_enabled() && t.is_int_active() { @@ -648,7 +643,7 @@ impl HPETState { // Halt main counter and disable interrupt generation. self.counter.set(self.get_ticks()); - for timer in self.timers.iter().take(self.get_num_timers()) { + for timer in self.timers.iter().take(self.num_timers) { timer.borrow_mut().del_timer(); } } @@ -671,7 +666,7 @@ impl HPETState { let new_val = val << shift; let cleared = new_val & self.int_status.get(); - for (index, timer) in self.timers.iter().take(self.get_num_timers()).enumerate() { + for (index, timer) in self.timers.iter().take(self.num_timers).enumerate() { if cleared & (1 << index) != 0 { timer.borrow_mut().update_irq(false); } @@ -724,19 +719,17 @@ impl HPETState { } } - fn realize(&self) { + fn realize(&self) -> qemu_api::Result<()> { + if self.num_timers < HPET_MIN_TIMERS || self.num_timers > HPET_MAX_TIMERS { + Err(format!( + "hpet.num_timers must be between {HPET_MIN_TIMERS} and {HPET_MAX_TIMERS}" + ))?; + } if self.int_route_cap == 0 { - // TODO: Add error binding: warn_report() - println!("Hpet's hpet-intcap property not initialized"); + Err("hpet.hpet-intcap property not initialized")?; } - self.hpet_id.set(HPETFwConfig::assign_hpet_id()); - - if self.num_timers.get() < HPET_MIN_TIMERS { - self.num_timers.set(HPET_MIN_TIMERS); - } else if self.num_timers.get() > HPET_MAX_TIMERS { - self.num_timers.set(HPET_MAX_TIMERS); - } + self.hpet_id.set(HPETFwConfig::assign_hpet_id()?); self.init_timer(); // 64-bit General Capabilities and ID Register; LegacyReplacementRoute. @@ -745,16 +738,17 @@ impl HPETState { 1 << HPET_CAP_COUNT_SIZE_CAP_SHIFT | 1 << HPET_CAP_LEG_RT_CAP_SHIFT | HPET_CAP_VENDER_ID_VALUE << HPET_CAP_VENDER_ID_SHIFT | - ((self.get_num_timers() - 1) as u64) << HPET_CAP_NUM_TIM_SHIFT | // indicate the last timer + ((self.num_timers - 1) as u64) << HPET_CAP_NUM_TIM_SHIFT | // indicate the last timer (HPET_CLK_PERIOD * FS_PER_NS) << HPET_CAP_CNT_CLK_PERIOD_SHIFT, // 10 ns ); self.init_gpio_in(2, HPETState::handle_legacy_irq); self.init_gpio_out(from_ref(&self.pit_enabled)); + Ok(()) } fn reset_hold(&self, _type: ResetType) { - for timer in self.timers.iter().take(self.get_num_timers()) { + for timer in self.timers.iter().take(self.num_timers) { timer.borrow_mut().reset(); } @@ -782,7 +776,7 @@ impl HPETState { GlobalRegister::try_from(addr).map(HPETRegister::Global) } else { let timer_id: usize = ((addr - 0x100) / 0x20) as usize; - if timer_id <= self.get_num_timers() { + if timer_id < self.num_timers { // TODO: Add trace point - trace_hpet_ram_[read|write]_timer_id(timer_id) TimerRegister::try_from(addr & 0x18) .map(|reg| HPETRegister::Timer(&self.timers[timer_id], reg)) @@ -853,12 +847,12 @@ impl HPETState { * also added to the migration stream. Check that it matches the value * that was configured. */ - self.num_timers_save.set(self.num_timers.get()); + self.num_timers_save.set(self.num_timers as u8); 0 } fn post_load(&self, _version_id: u8) -> i32 { - for timer in self.timers.iter().take(self.get_num_timers()) { + for timer in self.timers.iter().take(self.num_timers) { let mut t = timer.borrow_mut(); t.cmp64 = t.calculate_cmp64(t.get_state().counter.get(), t.cmp); @@ -883,7 +877,7 @@ impl HPETState { } fn validate_num_timers(&self, _version_id: u8) -> bool { - self.num_timers.get() == self.num_timers_save.get() + self.num_timers == self.num_timers_save.get().into() } } @@ -910,7 +904,7 @@ qemu_api::declare_properties! { c"timers", HPETState, num_timers, - unsafe { &qdev_prop_uint8 }, + unsafe { &qdev_prop_usize }, u8, default = HPET_MIN_TIMERS ), @@ -1015,16 +1009,16 @@ const VALIDATE_TIMERS_NAME: &CStr = c"num_timers must match"; static VMSTATE_HPET: VMStateDescription = VMStateDescription { name: c"hpet".as_ptr(), version_id: 2, - minimum_version_id: 1, + minimum_version_id: 2, pre_save: Some(hpet_pre_save), post_load: Some(hpet_post_load), fields: vmstate_fields! { vmstate_of!(HPETState, config), vmstate_of!(HPETState, int_status), vmstate_of!(HPETState, counter), - vmstate_of!(HPETState, num_timers_save).with_version_id(2), + vmstate_of!(HPETState, num_timers_save), vmstate_validate!(HPETState, VALIDATE_TIMERS_NAME, HPETState::validate_num_timers), - vmstate_struct!(HPETState, timers[0 .. num_timers], &VMSTATE_HPET_TIMER, BqlRefCell<HPETTimer>, HPETState::validate_num_timers).with_version_id(0), + vmstate_struct!(HPETState, timers[0 .. num_timers_save], &VMSTATE_HPET_TIMER, BqlRefCell<HPETTimer>, HPETState::validate_num_timers).with_version_id(0), }, subsections: vmstate_subsections! { VMSTATE_HPET_RTC_IRQ_LEVEL, @@ -1042,7 +1036,7 @@ impl DeviceImpl for HPETState { Some(&VMSTATE_HPET) } - const REALIZE: Option<fn(&Self)> = Some(Self::realize); + const REALIZE: Option<fn(&Self) -> qemu_api::Result<()>> = Some(Self::realize); } impl ResettablePhasesImpl for HPETState { diff --git a/rust/hw/timer/hpet/src/fw_cfg.rs b/rust/hw/timer/hpet/src/fw_cfg.rs index 6c10316..619d662 100644 --- a/rust/hw/timer/hpet/src/fw_cfg.rs +++ b/rust/hw/timer/hpet/src/fw_cfg.rs @@ -36,7 +36,7 @@ pub static mut hpet_fw_cfg: HPETFwConfig = HPETFwConfig { }; impl HPETFwConfig { - pub(crate) fn assign_hpet_id() -> usize { + pub(crate) fn assign_hpet_id() -> Result<usize, &'static str> { assert!(bql_locked()); // SAFETY: all accesses go through these methods, which guarantee // that the accesses are protected by the BQL. @@ -48,13 +48,12 @@ impl HPETFwConfig { } if fw_cfg.count == 8 { - // TODO: Add error binding: error_setg() - panic!("Only 8 instances of HPET is allowed"); + Err("Only 8 instances of HPET are allowed")?; } let id: usize = fw_cfg.count.into(); fw_cfg.count += 1; - id + Ok(id) } pub(crate) fn update_hpet_cfg(hpet_id: usize, timer_block_id: u32, address: u64) { diff --git a/rust/meson.build b/rust/meson.build index b1b3315..99ae795 100644 --- a/rust/meson.build +++ b/rust/meson.build @@ -1,9 +1,13 @@ +subproject('anyhow-1-rs', required: true) subproject('bilge-0.2-rs', required: true) subproject('bilge-impl-0.2-rs', required: true) +subproject('foreign-0.3-rs', required: true) subproject('libc-0.2-rs', required: true) +anyhow_rs = dependency('anyhow-1-rs') bilge_rs = dependency('bilge-0.2-rs') bilge_impl_rs = dependency('bilge-impl-0.2-rs') +foreign_rs = dependency('foreign-0.3-rs') libc_rs = dependency('libc-0.2-rs') subproject('proc-macro2-1-rs', required: true) diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs index 1034707..c18bb4e 100644 --- a/rust/qemu-api-macros/src/lib.rs +++ b/rust/qemu-api-macros/src/lib.rs @@ -203,8 +203,8 @@ fn derive_tryinto_body( Ok(quote! { #(const #discriminants: #repr = #name::#discriminants as #repr;)*; match value { - #(#discriminants => Ok(#name::#discriminants),)* - _ => Err(value), + #(#discriminants => core::result::Result::Ok(#name::#discriminants),)* + _ => core::result::Result::Err(value), } }) } @@ -236,7 +236,8 @@ fn derive_tryinto_or_error(input: DeriveInput) -> Result<proc_macro2::TokenStrea impl core::convert::TryFrom<#repr> for #name { type Error = #repr; - fn try_from(value: #repr) -> Result<Self, Self::Error> { + #[allow(ambiguous_associated_items)] + fn try_from(value: #repr) -> Result<Self, #repr> { #body } } diff --git a/rust/qemu-api/Cargo.toml b/rust/qemu-api/Cargo.toml index c96cf50..db7000d 100644 --- a/rust/qemu-api/Cargo.toml +++ b/rust/qemu-api/Cargo.toml @@ -15,7 +15,9 @@ rust-version.workspace = true [dependencies] qemu_api_macros = { path = "../qemu-api-macros" } +anyhow = "~1.0" libc = "0.2.162" +foreign = "~0.3.1" [features] default = ["debug_cell"] diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build index b532281..cac8595 100644 --- a/rust/qemu-api/meson.build +++ b/rust/qemu-api/meson.build @@ -19,6 +19,7 @@ _qemu_api_rs = static_library( 'src/cell.rs', 'src/chardev.rs', 'src/errno.rs', + 'src/error.rs', 'src/irq.rs', 'src/memory.rs', 'src/module.rs', @@ -35,7 +36,7 @@ _qemu_api_rs = static_library( override_options: ['rust_std=2021', 'build.rust_std=2021'], rust_abi: 'rust', rust_args: _qemu_api_cfg, - dependencies: [libc_rs, qemu_api_macros, qemuutil_rs, + dependencies: [anyhow_rs, foreign_rs, libc_rs, qemu_api_macros, qemuutil_rs, qom, hwcore, chardev, migration], ) diff --git a/rust/qemu-api/src/error.rs b/rust/qemu-api/src/error.rs new file mode 100644 index 0000000..e114fc4 --- /dev/null +++ b/rust/qemu-api/src/error.rs @@ -0,0 +1,416 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +//! Error propagation for QEMU Rust code +//! +//! This module contains [`Error`], the bridge between Rust errors and +//! [`Result`](std::result::Result)s and QEMU's C [`Error`](bindings::Error) +//! struct. +//! +//! For FFI code, [`Error`] provides functions to simplify conversion between +//! the Rust ([`Result<>`](std::result::Result)) and C (`Error**`) conventions: +//! +//! * [`ok_or_propagate`](crate::Error::ok_or_propagate), +//! [`bool_or_propagate`](crate::Error::bool_or_propagate), +//! [`ptr_or_propagate`](crate::Error::ptr_or_propagate) can be used to build +//! a C return value while also propagating an error condition +//! +//! * [`err_or_else`](crate::Error::err_or_else) and +//! [`err_or_unit`](crate::Error::err_or_unit) can be used to build a `Result` +//! +//! This module is most commonly used at the boundary between C and Rust code; +//! other code will usually access it through the +//! [`qemu_api::Result`](crate::Result) type alias, and will use the +//! [`std::error::Error`] interface to let C errors participate in Rust's error +//! handling functionality. +//! +//! Rust code can also create use this module to create an error object that +//! will be passed up to C code, though in most cases this will be done +//! transparently through the `?` operator. Errors can be constructed from a +//! simple error string, from an [`anyhow::Error`] to pass any other Rust error +//! type up to C code, or from a combination of the two. +//! +//! The third case, corresponding to [`Error::with_error`], is the only one that +//! requires mentioning [`qemu_api::Error`](crate::Error) explicitly. Similar +//! to how QEMU's C code handles errno values, the string and the +//! `anyhow::Error` object will be concatenated with `:` as the separator. + +use std::{ + borrow::Cow, + ffi::{c_char, c_int, c_void, CStr}, + fmt::{self, Display}, + panic, ptr, +}; + +use foreign::{prelude::*, OwnedPointer}; + +use crate::bindings; + +pub type Result<T> = std::result::Result<T, Error>; + +#[derive(Debug)] +pub struct Error { + msg: Option<Cow<'static, str>>, + /// Appends the print string of the error to the msg if not None + cause: Option<anyhow::Error>, + file: &'static str, + line: u32, +} + +impl std::error::Error for Error { + fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { + self.cause.as_ref().map(AsRef::as_ref) + } + + #[allow(deprecated)] + fn description(&self) -> &str { + self.msg + .as_deref() + .or_else(|| self.cause.as_deref().map(std::error::Error::description)) + .expect("no message nor cause?") + } +} + +impl Display for Error { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + let mut prefix = ""; + if let Some(ref msg) = self.msg { + write!(f, "{msg}")?; + prefix = ": "; + } + if let Some(ref cause) = self.cause { + write!(f, "{prefix}{cause}")?; + } else if prefix.is_empty() { + panic!("no message nor cause?"); + } + Ok(()) + } +} + +impl From<String> for Error { + #[track_caller] + fn from(msg: String) -> Self { + let location = panic::Location::caller(); + Error { + msg: Some(Cow::Owned(msg)), + cause: None, + file: location.file(), + line: location.line(), + } + } +} + +impl From<&'static str> for Error { + #[track_caller] + fn from(msg: &'static str) -> Self { + let location = panic::Location::caller(); + Error { + msg: Some(Cow::Borrowed(msg)), + cause: None, + file: location.file(), + line: location.line(), + } + } +} + +impl From<anyhow::Error> for Error { + #[track_caller] + fn from(error: anyhow::Error) -> Self { + let location = panic::Location::caller(); + Error { + msg: None, + cause: Some(error), + file: location.file(), + line: location.line(), + } + } +} + +impl Error { + /// Create a new error, prepending `msg` to the + /// description of `cause` + #[track_caller] + pub fn with_error(msg: impl Into<Cow<'static, str>>, cause: impl Into<anyhow::Error>) -> Self { + let location = panic::Location::caller(); + Error { + msg: Some(msg.into()), + cause: Some(cause.into()), + file: location.file(), + line: location.line(), + } + } + + /// Consume a result, returning `false` if it is an error and + /// `true` if it is successful. The error is propagated into + /// `errp` like the C API `error_propagate` would do. + /// + /// # Safety + /// + /// `errp` must be a valid argument to `error_propagate`; + /// typically it is received from C code and need not be + /// checked further at the Rust↔C boundary. + pub unsafe fn bool_or_propagate(result: Result<()>, errp: *mut *mut bindings::Error) -> bool { + // SAFETY: caller guarantees errp is valid + unsafe { Self::ok_or_propagate(result, errp) }.is_some() + } + + /// Consume a result, returning a `NULL` pointer if it is an error and + /// a C representation of the contents if it is successful. This is + /// similar to the C API `error_propagate`, but it panics if `*errp` + /// is not `NULL`. + /// + /// # Safety + /// + /// `errp` must be a valid argument to `error_propagate`; + /// typically it is received from C code and need not be + /// checked further at the Rust↔C boundary. + /// + /// See [`propagate`](Error::propagate) for more information. + #[must_use] + pub unsafe fn ptr_or_propagate<T: CloneToForeign>( + result: Result<T>, + errp: *mut *mut bindings::Error, + ) -> *mut T::Foreign { + // SAFETY: caller guarantees errp is valid + unsafe { Self::ok_or_propagate(result, errp) }.clone_to_foreign_ptr() + } + + /// Consume a result in the same way as `self.ok()`, but also propagate + /// a possible error into `errp`. This is similar to the C API + /// `error_propagate`, but it panics if `*errp` is not `NULL`. + /// + /// # Safety + /// + /// `errp` must be a valid argument to `error_propagate`; + /// typically it is received from C code and need not be + /// checked further at the Rust↔C boundary. + /// + /// See [`propagate`](Error::propagate) for more information. + pub unsafe fn ok_or_propagate<T>( + result: Result<T>, + errp: *mut *mut bindings::Error, + ) -> Option<T> { + result.map_err(|err| unsafe { err.propagate(errp) }).ok() + } + + /// Equivalent of the C function `error_propagate`. Fill `*errp` + /// with the information container in `self` if `errp` is not NULL; + /// then consume it. + /// + /// This is similar to the C API `error_propagate`, but it panics if + /// `*errp` is not `NULL`. + /// + /// # Safety + /// + /// `errp` must be a valid argument to `error_propagate`; it can be + /// `NULL` or it can point to any of: + /// * `error_abort` + /// * `error_fatal` + /// * a local variable of (C) type `Error *` + /// + /// Typically `errp` is received from C code and need not be + /// checked further at the Rust↔C boundary. + pub unsafe fn propagate(self, errp: *mut *mut bindings::Error) { + if errp.is_null() { + return; + } + + // SAFETY: caller guarantees that errp and *errp are valid + unsafe { + assert_eq!(*errp, ptr::null_mut()); + bindings::error_propagate(errp, self.clone_to_foreign_ptr()); + } + } + + /// Convert a C `Error*` into a Rust `Result`, using + /// `Ok(())` if `c_error` is NULL. Free the `Error*`. + /// + /// # Safety + /// + /// `c_error` must be `NULL` or valid; typically it was initialized + /// with `ptr::null_mut()` and passed by reference to a C function. + pub unsafe fn err_or_unit(c_error: *mut bindings::Error) -> Result<()> { + // SAFETY: caller guarantees c_error is valid + unsafe { Self::err_or_else(c_error, || ()) } + } + + /// Convert a C `Error*` into a Rust `Result`, calling `f()` to + /// obtain an `Ok` value if `c_error` is NULL. Free the `Error*`. + /// + /// # Safety + /// + /// `c_error` must be `NULL` or point to a valid C [`struct + /// Error`](bindings::Error); typically it was initialized with + /// `ptr::null_mut()` and passed by reference to a C function. + pub unsafe fn err_or_else<T, F: FnOnce() -> T>( + c_error: *mut bindings::Error, + f: F, + ) -> Result<T> { + // SAFETY: caller guarantees c_error is valid + let err = unsafe { Option::<Self>::from_foreign(c_error) }; + match err { + None => Ok(f()), + Some(err) => Err(err), + } + } +} + +impl FreeForeign for Error { + type Foreign = bindings::Error; + + unsafe fn free_foreign(p: *mut bindings::Error) { + // SAFETY: caller guarantees p is valid + unsafe { + bindings::error_free(p); + } + } +} + +impl CloneToForeign for Error { + fn clone_to_foreign(&self) -> OwnedPointer<Self> { + // SAFETY: all arguments are controlled by this function + unsafe { + let err: *mut c_void = libc::malloc(std::mem::size_of::<bindings::Error>()); + let err: &mut bindings::Error = &mut *err.cast(); + *err = bindings::Error { + msg: format!("{self}").clone_to_foreign_ptr(), + err_class: bindings::ERROR_CLASS_GENERIC_ERROR, + src_len: self.file.len() as c_int, + src: self.file.as_ptr().cast::<c_char>(), + line: self.line as c_int, + func: ptr::null_mut(), + hint: ptr::null_mut(), + }; + OwnedPointer::new(err) + } + } +} + +impl FromForeign for Error { + unsafe fn cloned_from_foreign(c_error: *const bindings::Error) -> Self { + // SAFETY: caller guarantees c_error is valid + unsafe { + let error = &*c_error; + let file = if error.src_len < 0 { + // NUL-terminated + CStr::from_ptr(error.src).to_str() + } else { + // Can become str::from_utf8 with Rust 1.87.0 + std::str::from_utf8(std::slice::from_raw_parts( + &*error.src.cast::<u8>(), + error.src_len as usize, + )) + }; + + Error { + msg: FromForeign::cloned_from_foreign(error.msg), + cause: None, + file: file.unwrap(), + line: error.line as u32, + } + } + } +} + +#[cfg(test)] +mod tests { + use std::ffi::CStr; + + use anyhow::anyhow; + use foreign::OwnedPointer; + + use super::*; + use crate::{assert_match, bindings}; + + #[track_caller] + fn error_for_test(msg: &CStr) -> OwnedPointer<Error> { + // SAFETY: all arguments are controlled by this function + let location = panic::Location::caller(); + unsafe { + let err: *mut c_void = libc::malloc(std::mem::size_of::<bindings::Error>()); + let err: &mut bindings::Error = &mut *err.cast(); + *err = bindings::Error { + msg: msg.clone_to_foreign_ptr(), + err_class: bindings::ERROR_CLASS_GENERIC_ERROR, + src_len: location.file().len() as c_int, + src: location.file().as_ptr().cast::<c_char>(), + line: location.line() as c_int, + func: ptr::null_mut(), + hint: ptr::null_mut(), + }; + OwnedPointer::new(err) + } + } + + unsafe fn error_get_pretty<'a>(local_err: *mut bindings::Error) -> &'a CStr { + unsafe { CStr::from_ptr(bindings::error_get_pretty(local_err)) } + } + + #[test] + #[allow(deprecated)] + fn test_description() { + use std::error::Error; + + assert_eq!(super::Error::from("msg").description(), "msg"); + assert_eq!(super::Error::from("msg".to_owned()).description(), "msg"); + } + + #[test] + fn test_display() { + assert_eq!(&*format!("{}", Error::from("msg")), "msg"); + assert_eq!(&*format!("{}", Error::from("msg".to_owned())), "msg"); + assert_eq!(&*format!("{}", Error::from(anyhow!("msg"))), "msg"); + + assert_eq!( + &*format!("{}", Error::with_error("msg", anyhow!("cause"))), + "msg: cause" + ); + } + + #[test] + fn test_bool_or_propagate() { + unsafe { + let mut local_err: *mut bindings::Error = ptr::null_mut(); + + assert!(Error::bool_or_propagate(Ok(()), &mut local_err)); + assert_eq!(local_err, ptr::null_mut()); + + let my_err = Error::from("msg"); + assert!(!Error::bool_or_propagate(Err(my_err), &mut local_err)); + assert_ne!(local_err, ptr::null_mut()); + assert_eq!(error_get_pretty(local_err), c"msg"); + bindings::error_free(local_err); + } + } + + #[test] + fn test_ptr_or_propagate() { + unsafe { + let mut local_err: *mut bindings::Error = ptr::null_mut(); + + let ret = Error::ptr_or_propagate(Ok("abc".to_owned()), &mut local_err); + assert_eq!(String::from_foreign(ret), "abc"); + assert_eq!(local_err, ptr::null_mut()); + + let my_err = Error::from("msg"); + assert_eq!( + Error::ptr_or_propagate(Err::<String, _>(my_err), &mut local_err), + ptr::null_mut() + ); + assert_ne!(local_err, ptr::null_mut()); + assert_eq!(error_get_pretty(local_err), c"msg"); + bindings::error_free(local_err); + } + } + + #[test] + fn test_err_or_unit() { + unsafe { + let result = Error::err_or_unit(ptr::null_mut()); + assert_match!(result, Ok(())); + + let err = error_for_test(c"msg"); + let err = Error::err_or_unit(err.into_inner()).unwrap_err(); + assert_eq!(&*format!("{err}"), "msg"); + } + } +} diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs index 234a94e..93902fc 100644 --- a/rust/qemu-api/src/lib.rs +++ b/rust/qemu-api/src/lib.rs @@ -19,6 +19,7 @@ pub mod callbacks; pub mod cell; pub mod chardev; pub mod errno; +pub mod error; pub mod irq; pub mod memory; pub mod module; @@ -34,6 +35,8 @@ use std::{ ffi::c_void, }; +pub use error::{Error, Result}; + #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)] extern "C" { fn g_aligned_alloc0( diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs index 1279d7a..0610959 100644 --- a/rust/qemu-api/src/qdev.rs +++ b/rust/qemu-api/src/qdev.rs @@ -12,10 +12,11 @@ use std::{ pub use bindings::{ClockEvent, DeviceClass, Property, ResetType}; use crate::{ - bindings::{self, qdev_init_gpio_in, qdev_init_gpio_out, Error, ResettableClass}, + bindings::{self, qdev_init_gpio_in, qdev_init_gpio_out, ResettableClass}, callbacks::FnCall, cell::{bql_locked, Opaque}, chardev::Chardev, + error::{Error, Result}, irq::InterruptSource, prelude::*, qom::{ObjectClass, ObjectImpl, Owned}, @@ -108,7 +109,7 @@ pub trait DeviceImpl: ObjectImpl + ResettablePhasesImpl + IsA<DeviceState> { /// /// If not `None`, the parent class's `realize` method is overridden /// with the function pointed to by `REALIZE`. - const REALIZE: Option<fn(&Self)> = None; + const REALIZE: Option<fn(&Self) -> Result<()>> = None; /// An array providing the properties that the user can set on the /// device. Not a `const` because referencing statics in constants @@ -134,10 +135,13 @@ pub trait DeviceImpl: ObjectImpl + ResettablePhasesImpl + IsA<DeviceState> { /// readable/writeable from one thread at any time. unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>( dev: *mut bindings::DeviceState, - _errp: *mut *mut Error, + errp: *mut *mut bindings::Error, ) { let state = NonNull::new(dev).unwrap().cast::<T>(); - T::REALIZE.unwrap()(unsafe { state.as_ref() }); + let result = T::REALIZE.unwrap()(unsafe { state.as_ref() }); + unsafe { + Error::ok_or_propagate(result, errp); + } } unsafe impl InterfaceType for ResettableClass { diff --git a/rust/wrapper.h b/rust/wrapper.h index beddd9a..6060d3b 100644 --- a/rust/wrapper.h +++ b/rust/wrapper.h @@ -60,6 +60,7 @@ typedef enum memory_order { #include "hw/qdev-properties-system.h" #include "hw/irq.h" #include "qapi/error.h" +#include "qapi/error-internal.h" #include "migration/vmstate.h" #include "chardev/char-serial.h" #include "exec/memattrs.h" |