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Merge pull request #3992 from YohDeadfall/android-syscall
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Android: Added syscall support
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RalfJung authored Oct 28, 2024
2 parents 3e8619a + b8618fe commit fb28524
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Showing 7 changed files with 93 additions and 70 deletions.
2 changes: 1 addition & 1 deletion ci/ci.sh
Original file line number Diff line number Diff line change
Expand Up @@ -154,7 +154,7 @@ case $HOST_TARGET in
TEST_TARGET=i686-unknown-freebsd run_tests_minimal $BASIC $UNIX time hashmap random threadname pthread fs libc-pipe
TEST_TARGET=x86_64-unknown-illumos run_tests_minimal $BASIC $UNIX time hashmap random thread sync available-parallelism tls libc-pipe
TEST_TARGET=x86_64-pc-solaris run_tests_minimal $BASIC $UNIX time hashmap random thread sync available-parallelism tls libc-pipe
TEST_TARGET=aarch64-linux-android run_tests_minimal $BASIC $UNIX time hashmap threadname pthread
TEST_TARGET=aarch64-linux-android run_tests_minimal $BASIC $UNIX time hashmap random sync threadname pthread
TEST_TARGET=wasm32-wasip2 run_tests_minimal $BASIC wasm
TEST_TARGET=wasm32-unknown-unknown run_tests_minimal no_std empty_main wasm # this target doesn't really have std
TEST_TARGET=thumbv7em-none-eabihf run_tests_minimal no_std
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4 changes: 4 additions & 0 deletions src/shims/unix/android/foreign_items.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@ use rustc_span::Symbol;
use rustc_target::spec::abi::Abi;

use crate::shims::unix::android::thread::prctl;
use crate::shims::unix::linux::syscall::syscall;
use crate::*;

pub fn is_dyn_sym(_name: &str) -> bool {
Expand All @@ -26,6 +27,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
this.write_scalar(errno_place.to_ref(this).to_scalar(), dest)?;
}

// Dynamically invoked syscalls
"syscall" => syscall(this, link_name, abi, args, dest)?,

// Threading
"prctl" => prctl(this, link_name, abi, args, dest)?,

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51 changes: 2 additions & 49 deletions src/shims/unix/linux/foreign_items.rs
Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,7 @@ use rustc_target::spec::abi::Abi;
use self::shims::unix::linux::epoll::EvalContextExt as _;
use self::shims::unix::linux::eventfd::EvalContextExt as _;
use self::shims::unix::linux::mem::EvalContextExt as _;
use self::shims::unix::linux::sync::futex;
use crate::helpers::check_min_arg_count;
use self::shims::unix::linux::syscall::syscall;
use crate::machine::{SIGRTMAX, SIGRTMIN};
use crate::shims::unix::*;
use crate::*;
Expand Down Expand Up @@ -117,53 +116,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {

// Dynamically invoked syscalls
"syscall" => {
// We do not use `check_shim` here because `syscall` is variadic. The argument
// count is checked bellow.
this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
// The syscall variadic function is legal to call with more arguments than needed,
// extra arguments are simply ignored. The important check is that when we use an
// argument, we have to also check all arguments *before* it to ensure that they
// have the right type.

let sys_getrandom = this.eval_libc("SYS_getrandom").to_target_usize(this)?;
let sys_futex = this.eval_libc("SYS_futex").to_target_usize(this)?;
let sys_eventfd2 = this.eval_libc("SYS_eventfd2").to_target_usize(this)?;

let [op] = check_min_arg_count("syscall", args)?;
match this.read_target_usize(op)? {
// `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
// is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
num if num == sys_getrandom => {
// Used by getrandom 0.1
// The first argument is the syscall id, so skip over it.
let [_, ptr, len, flags] =
check_min_arg_count("syscall(SYS_getrandom, ...)", args)?;

let ptr = this.read_pointer(ptr)?;
let len = this.read_target_usize(len)?;
// The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
// neither of which have any effect on our current PRNG.
// See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
let _flags = this.read_scalar(flags)?.to_i32()?;

this.gen_random(ptr, len)?;
this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
}
// `futex` is used by some synchronization primitives.
num if num == sys_futex => {
futex(this, args, dest)?;
}
num if num == sys_eventfd2 => {
let [_, initval, flags] =
check_min_arg_count("syscall(SYS_evetfd2, ...)", args)?;

let result = this.eventfd(initval, flags)?;
this.write_int(result.to_i32()?, dest)?;
}
num => {
throw_unsup_format!("syscall: unsupported syscall number {num}");
}
}
syscall(this, link_name, abi, args, dest)?;
}

// Miscellaneous
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1 change: 1 addition & 0 deletions src/shims/unix/linux/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -3,3 +3,4 @@ pub mod eventfd;
pub mod foreign_items;
pub mod mem;
pub mod sync;
pub mod syscall;
63 changes: 63 additions & 0 deletions src/shims/unix/linux/syscall.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,63 @@
use rustc_span::Symbol;
use rustc_target::spec::abi::Abi;

use self::shims::unix::linux::eventfd::EvalContextExt as _;
use crate::helpers::check_min_arg_count;
use crate::shims::unix::linux::sync::futex;
use crate::*;

pub fn syscall<'tcx>(
this: &mut MiriInterpCx<'tcx>,
link_name: Symbol,
abi: Abi,
args: &[OpTy<'tcx>],
dest: &MPlaceTy<'tcx>,
) -> InterpResult<'tcx> {
// We do not use `check_shim` here because `syscall` is variadic. The argument
// count is checked bellow.
this.check_abi_and_shim_symbol_clash(abi, Abi::C { unwind: false }, link_name)?;
// The syscall variadic function is legal to call with more arguments than needed,
// extra arguments are simply ignored. The important check is that when we use an
// argument, we have to also check all arguments *before* it to ensure that they
// have the right type.

let sys_getrandom = this.eval_libc("SYS_getrandom").to_target_usize(this)?;
let sys_futex = this.eval_libc("SYS_futex").to_target_usize(this)?;
let sys_eventfd2 = this.eval_libc("SYS_eventfd2").to_target_usize(this)?;

let [op] = check_min_arg_count("syscall", args)?;
match this.read_target_usize(op)? {
// `libc::syscall(NR_GETRANDOM, buf.as_mut_ptr(), buf.len(), GRND_NONBLOCK)`
// is called if a `HashMap` is created the regular way (e.g. HashMap<K, V>).
num if num == sys_getrandom => {
// Used by getrandom 0.1
// The first argument is the syscall id, so skip over it.
let [_, ptr, len, flags] = check_min_arg_count("syscall(SYS_getrandom, ...)", args)?;

let ptr = this.read_pointer(ptr)?;
let len = this.read_target_usize(len)?;
// The only supported flags are GRND_RANDOM and GRND_NONBLOCK,
// neither of which have any effect on our current PRNG.
// See <https://github.com/rust-lang/rust/pull/79196> for a discussion of argument sizes.
let _flags = this.read_scalar(flags)?.to_i32()?;

this.gen_random(ptr, len)?;
this.write_scalar(Scalar::from_target_usize(len, this), dest)?;
}
// `futex` is used by some synchronization primitives.
num if num == sys_futex => {
futex(this, args, dest)?;
}
num if num == sys_eventfd2 => {
let [_, initval, flags] = check_min_arg_count("syscall(SYS_evetfd2, ...)", args)?;

let result = this.eventfd(initval, flags)?;
this.write_int(result.to_i32()?, dest)?;
}
num => {
throw_unsup_format!("syscall: unsupported syscall number {num}");
}
};

interp_ok(())
}
1 change: 1 addition & 0 deletions tests/pass-dep/concurrency/linux-futex.rs
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
//@only-target: linux
//@only-target: android
//@compile-flags: -Zmiri-disable-isolation

// FIXME(static_mut_refs): Do not allow `static_mut_refs` lint
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41 changes: 21 additions & 20 deletions tests/pass-dep/libc/libc-random.rs
Original file line number Diff line number Diff line change
Expand Up @@ -28,26 +28,27 @@ fn test_getrandom() {

let mut buf = [0u8; 5];
unsafe {
#[cfg(target_os = "linux")]
assert_eq!(
libc::syscall(
libc::SYS_getrandom,
ptr::null_mut::<libc::c_void>(),
0 as libc::size_t,
0 as libc::c_uint,
),
0,
);
#[cfg(target_os = "linux")]
assert_eq!(
libc::syscall(
libc::SYS_getrandom,
buf.as_mut_ptr() as *mut libc::c_void,
5 as libc::size_t,
0 as libc::c_uint,
),
5,
);
#[cfg(any(target_os = "linux", target_os = "android"))]
{
assert_eq!(
libc::syscall(
libc::SYS_getrandom,
ptr::null_mut::<libc::c_void>(),
0 as libc::size_t,
0 as libc::c_uint,
),
0,
);
assert_eq!(
libc::syscall(
libc::SYS_getrandom,
buf.as_mut_ptr() as *mut libc::c_void,
5 as libc::size_t,
0 as libc::c_uint,
),
5,
);
}

assert_eq!(
libc::getrandom(ptr::null_mut::<libc::c_void>(), 0 as libc::size_t, 0 as libc::c_uint),
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