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Add support for FUTEX_WAIT_BITSET(bitset=MAX).

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This commit is contained in:
Mara Bos 2022-04-06 23:03:52 +02:00
parent fb01df538e
commit 37cefa32d2
1 changed files with 40 additions and 9 deletions
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49
src/shims/posix/linux/sync.rs
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@ -36,6 +36,7 @@ pub fn futex<'tcx>(
let futex_private = this.eval_libc_i32("FUTEX_PRIVATE_FLAG")?;
let futex_wait = this.eval_libc_i32("FUTEX_WAIT")?;
let futex_wait_bitset = this.eval_libc_i32("FUTEX_WAIT_BITSET")?;
let futex_wake = this.eval_libc_i32("FUTEX_WAKE")?;
let futex_realtime = this.eval_libc_i32("FUTEX_CLOCK_REALTIME")?;
@ -45,12 +46,32 @@ pub fn futex<'tcx>(
// FUTEX_WAIT: (int *addr, int op = FUTEX_WAIT, int val, const timespec *timeout)
// Blocks the thread if *addr still equals val. Wakes up when FUTEX_WAKE is called on the same address,
// or *timeout expires. `timeout == null` for an infinite timeout.
op if op & !futex_realtime == futex_wait => {
if args.len() < 5 {
throw_ub_format!(
"incorrect number of arguments for `futex` syscall with `op=FUTEX_WAIT`: got {}, expected at least 5",
args.len()
);
//
// FUTEX_WAIT_BITSET: (int *addr, int op = FUTEX_WAIT_BITSET, int val, const timespec *timeout, int *_ignored, unsigned int bitset)
// When bitset is u32::MAX, this is identical to FUTEX_WAIT, except the timeout is absolute rather than relative.
op if op & !futex_realtime == futex_wait || op & !futex_realtime == futex_wait_bitset => {
let wait_bitset = op & !futex_realtime == futex_wait_bitset;
if wait_bitset {
if args.len() != 7 {
throw_ub_format!(
"incorrect number of arguments for `futex` syscall with `op=FUTEX_WAIT_BITSET`: got {}, expected 7",
args.len()
);
}
let bitset = this.read_scalar(&args[6])?.to_u32()?;
if bitset != u32::MAX {
throw_unsup_format!("Miri does not support `futex` syscall with `op=FUTEX_WAIT_BITSET` with a bitset other than UINT_MAX");
}
} else {
if args.len() < 5 {
throw_ub_format!(
"incorrect number of arguments for `futex` syscall with `op=FUTEX_WAIT`: got {}, expected at least 5",
args.len()
);
}
}
// `deref_operand` but not actually dereferencing the ptr yet (it might be NULL!).
@ -70,10 +91,20 @@ pub fn futex<'tcx>(
return Ok(());
}
};
Some(if op & futex_realtime != 0 {
Time::RealTime(SystemTime::now().checked_add(duration).unwrap())
Some(if wait_bitset {
// FUTEX_WAIT_BITSET uses an absolute timestamp.
if op & futex_realtime != 0 {
Time::RealTime(SystemTime::UNIX_EPOCH.checked_add(duration).unwrap())
} else {
Time::Monotonic(this.machine.time_anchor.checked_add(duration).unwrap())
}
} else {
Time::Monotonic(Instant::now().checked_add(duration).unwrap())
// FUTEX_WAIT uses a relative timestamp.
if op & futex_realtime != 0 {
Time::RealTime(SystemTime::now().checked_add(duration).unwrap())
} else {
Time::Monotonic(Instant::now().checked_add(duration).unwrap())
}
})
};
// Check the pointer for alignment and validity.