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Use prlimit64 unconditionally in the linux_raw backend. #968

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merged 1 commit into from
Dec 8, 2023
Merged

Use prlimit64 unconditionally in the linux_raw backend. #968

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87 changes: 7 additions & 80 deletions src/backend/linux_raw/process/syscalls.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,8 @@ use crate::utils::as_mut_ptr;
use core::mem::MaybeUninit;
use core::ptr::{null, null_mut};
use linux_raw_sys::general::{
membarrier_cmd, membarrier_cmd_flag, rlimit, rlimit64, PRIO_PGRP, PRIO_PROCESS, PRIO_USER,
RLIM64_INFINITY, RLIM_INFINITY,
membarrier_cmd, membarrier_cmd_flag, rlimit64, PRIO_PGRP, PRIO_PROCESS, PRIO_USER,
RLIM64_INFINITY,
};
#[cfg(feature = "fs")]
use {crate::backend::conv::ret_c_uint_infallible, crate::fs::Mode};
Expand Down Expand Up @@ -299,52 +299,17 @@ pub(crate) fn setpriority_process(pid: Option<Pid>, priority: i32) -> io::Result
pub(crate) fn getrlimit(limit: Resource) -> Rlimit {
let mut result = MaybeUninit::<rlimit64>::uninit();
unsafe {
match ret(syscall!(
ret_infallible(syscall!(
__NR_prlimit64,
c_uint(0),
limit,
null::<c::c_void>(),
&mut result
)) {
Ok(()) => rlimit_from_linux(result.assume_init()),
Err(err) => {
debug_assert_eq!(err, io::Errno::NOSYS);
getrlimit_old(limit)
}
}
));
rlimit_from_linux(result.assume_init())
}
}

/// The old 32-bit-only `getrlimit` syscall, for when we lack the new
/// `prlimit64`.
unsafe fn getrlimit_old(limit: Resource) -> Rlimit {
let mut result = MaybeUninit::<rlimit>::uninit();

// On these platforms, `__NR_getrlimit` is called `__NR_ugetrlimit`.
#[cfg(any(
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64",
target_arch = "x86",
))]
{
ret_infallible(syscall!(__NR_ugetrlimit, limit, &mut result));
}

// On these platforms, it's just `__NR_getrlimit`.
#[cfg(not(any(
target_arch = "arm",
target_arch = "powerpc",
target_arch = "powerpc64",
target_arch = "x86",
)))]
{
ret_infallible(syscall!(__NR_getrlimit, limit, &mut result));
}

rlimit_from_linux_old(result.assume_init())
}

#[inline]
pub(crate) fn setrlimit(limit: Resource, new: Rlimit) -> io::Result<()> {
unsafe {
Expand All @@ -357,19 +322,11 @@ pub(crate) fn setrlimit(limit: Resource, new: Rlimit) -> io::Result<()> {
null_mut::<c::c_void>()
)) {
Ok(()) => Ok(()),
Err(io::Errno::NOSYS) => setrlimit_old(limit, new),
Err(err) => Err(err),
}
}
}

/// The old 32-bit-only `setrlimit` syscall, for when we lack the new
/// `prlimit64`.
unsafe fn setrlimit_old(limit: Resource, new: Rlimit) -> io::Result<()> {
let lim = rlimit_to_linux_old(new)?;
ret(syscall_readonly!(__NR_setrlimit, limit, by_ref(&lim)))
}

#[inline]
pub(crate) fn prlimit(pid: Option<Pid>, limit: Resource, new: Rlimit) -> io::Result<Rlimit> {
let lim = rlimit_to_linux(new);
Expand All @@ -391,12 +348,12 @@ pub(crate) fn prlimit(pid: Option<Pid>, limit: Resource, new: Rlimit) -> io::Res
/// Convert a Rust [`Rlimit`] to a C `rlimit64`.
#[inline]
fn rlimit_from_linux(lim: rlimit64) -> Rlimit {
let current = if lim.rlim_cur as u64 == RLIM64_INFINITY as u64 {
let current = if lim.rlim_cur == RLIM64_INFINITY as _ {
None
} else {
Some(lim.rlim_cur)
};
let maximum = if lim.rlim_max as u64 == RLIM64_INFINITY as u64 {
let maximum = if lim.rlim_max == RLIM64_INFINITY as _ {
None
} else {
Some(lim.rlim_max)
Expand All @@ -418,36 +375,6 @@ fn rlimit_to_linux(lim: Rlimit) -> rlimit64 {
rlimit64 { rlim_cur, rlim_max }
}

/// Like `rlimit_from_linux` but uses Linux's old 32-bit `rlimit`.
#[allow(clippy::useless_conversion)]
fn rlimit_from_linux_old(lim: rlimit) -> Rlimit {
let current = if lim.rlim_cur as u32 == RLIM_INFINITY as u32 {
None
} else {
Some(lim.rlim_cur.into())
};
let maximum = if lim.rlim_max as u32 == RLIM_INFINITY as u32 {
None
} else {
Some(lim.rlim_max.into())
};
Rlimit { current, maximum }
}

/// Like `rlimit_to_linux` but uses Linux's old 32-bit `rlimit`.
#[allow(clippy::useless_conversion)]
fn rlimit_to_linux_old(lim: Rlimit) -> io::Result<rlimit> {
let rlim_cur = match lim.current {
Some(r) => r.try_into().map_err(|_e| io::Errno::INVAL)?,
None => RLIM_INFINITY as _,
};
let rlim_max = match lim.maximum {
Some(r) => r.try_into().map_err(|_e| io::Errno::INVAL)?,
None => RLIM_INFINITY as _,
};
Ok(rlimit { rlim_cur, rlim_max })
}

#[inline]
pub(crate) fn wait(waitopts: WaitOptions) -> io::Result<Option<(Pid, WaitStatus)>> {
_waitpid(!0, waitopts)
Expand Down
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